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Sample records for antibiotic-resistant staphylococcus aureus

  1. Determining of antibiotic resistance profile inStaphylococcus aureus isolates

    Institute of Scientific and Technical Information of China (English)

    Hossein Motamedi; Hadis Mirzabeigi; Tahere Shirali

    2010-01-01

    Objective:To determine the pattern of antibiotic resistance amongStaphylococcus aureus (S. aureus) isolates from clinical specimens and to identify community-acquired methicillin-resistantStaphylococcus aureus(CA-MRSA)in specimens that have been collected from patients referring to one of the hospitals of Ahvaz.Methods:S. aureus isolates from a hospital in Ahvaz were screened for resistance to various antibiotics including methicillin. The susceptibility of the isolates was determined by Kirby-Bauer disc diffusion method. TheMRSA was also treated with ethidium bromide to find the origin of resistance.Results: Among the bacterial isolates, all of 11S. aureus were resistant to methicillin and cefixime,2 were resistant to ciprofloxacine,6 were resistant to tetracycline and the reminder were sensitive or intermediate to other antibiotics. The treated isolates were reminded resistant to methicillin and this suggested that the plasmid was not the origin of resistance in these isolates.Conclusions: These results showed that infection due toMRSA is widespread in Ahvaz and with respect to the spread of vancomycin resistance among MRSA and appearance of overwhelming infections. It is necessary to identify continuously the profile of antibiotic resistance amongS. aureus isolates in other regions and finding appropriate antibiotic for infection control and eradication.

  2. Facing antibiotic resistance: Staphylococcus aureus phages as a medical tool.

    Science.gov (United States)

    Kaźmierczak, Zuzanna; Górski, Andrzej; Dąbrowska, Krystyna

    2014-07-01

    Staphylococcus aureus is a common and often virulent pathogen in humans. This bacterium is widespread, being present on the skin and in the nose of healthy people. Staphylococcus aureus can cause infections with severe outcomes ranging from pustules to sepsis and death. The introduction of antibiotics led to a general belief that the problem of bacterial infections would be solved. Nonetheless, pathogens including staphylococci have evolved mechanisms of drug resistance. Among current attempts to address this problem, phage therapy offers a promising alternative to combat staphylococcal infections. Here, we present an overview of current knowledge on staphylococcal infections and bacteriophages able to kill Staphylococcus, including experimental studies and available data on their clinical use.

  3. Facing Antibiotic Resistance: Staphylococcus aureus Phages as a Medical Tool

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    Zuzanna Kaźmierczak

    2014-07-01

    Full Text Available Staphylococcus aureus is a common and often virulent pathogen in humans. This bacterium is widespread, being present on the skin and in the nose of healthy people. Staphylococcus aureus can cause infections with severe outcomes ranging from pustules to sepsis and death. The introduction of antibiotics led to a general belief that the problem of bacterial infections would be solved. Nonetheless, pathogens including staphylococci have evolved mechanisms of drug resistance. Among current attempts to address this problem, phage therapy offers a promising alternative to combat staphylococcal infections. Here, we present an overview of current knowledge on staphylococcal infections and bacteriophages able to kill Staphylococcus, including experimental studies and available data on their clinical use.

  4. Staphylococcus aureus phage types and their correlation to antibiotic resistance

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    Mehndiratta P

    2010-10-01

    Full Text Available Context: Staphylococcus aureus is one of the most devastating human pathogen. The organism has a differential ability to spread and cause outbreak of infections. Characterization of these strains is important to control the spread of infection in the hospitals as well as in the community. Aim: To identify the currently existing phage groups of Staphylococcus aureus, their prevalence and resistance to antibiotics. Materials and Methods: Study was undertaken on 252 Staphylococcus aureus strains isolated from clinical samples. Strains were phage typed and their resistance to antibiotics was determined following standard microbiological procedures. Statistical Analysis: Chi square test was used to compare the antibiotic susceptibility between methicillin resistant Staph. aureus (MRSA and methicillin sensitive S. aureus (MSSA strains. Results: Prevalence of MRSA and MSSA strains was found to be 29.36% and 70.65% respectively. Of these 17.56% of MRSA and 40.44% of MSSA strains were community acquired. All the MSSA strains belonging to phage type 81 from the community were sensitive to all the antibiotics tested including clindamycin and were resistant to penicillin. Forty five percent strains of phage group III and 39% of non-typable MRSA strains from the hospital were resistant to multiple antibiotics. Conclusion: The study revealed that predominant phage group amongst MRSA strains was phage group III and amongst MSSA from the community was phage group NA (phage type 81. MSSA strains isolated from the community differed significantly from hospital strains in their phage type and antibiotic susceptibility. A good correlation was observed between community acquired strains of phage type 81 and sensitivity to gentamycin and clindamycin.

  5. Short communication: prevalence and antibiotic resistance of Staphylococcus aureus isolated from bovine clinical mastitis.

    Science.gov (United States)

    Jamali, Hossein; Radmehr, Behrad; Ismail, Salmah

    2014-01-01

    The aims of this study were to determine the prevalence and antibiotic resistance of Staphylococcus aureus isolated from bovine clinical mastitis in Varamin, Tehran Province, Iran. All of the isolated Staph. aureus were identified by morphology and culture and confirmed using the API Staph identification system (bioMérieux, Marcy-l'Étoile, France). Antibiotic resistance genes were detected by PCR with oligonucleotide primers specific for each gene. Staphylococcus aureus was recovered from 43 of 207 (20.1%) bovine clinical milk samples. Using disk diffusion, methicillin-resistant Staph. aureus was detected in 5 of 43 (11.6%) samples. The pathogen showed high resistance against penicillin G (86%) and tetracycline (76.7%). The blaZ (penicillin) (86%), tetM (tetracycline), and ermC (erythromycin) genes (39.5% each) were the most prevalent antibiotic resistance genes. The findings of this study are useful for designing specific control programs for bovine clinical mastitis caused by Staph. aureus in this region of Iran.

  6. Bacteriophage-mediated acquisition of antibiotic resistance by Staphylococcus aureus type 88.

    OpenAIRE

    Schaefler, S.

    1982-01-01

    Antibiotic-resistant Staphylococcus aureus strains of phage type 88, lysogenic for phage 188, when grown in mixed culture with a nonlysogenic novobiocin-resistant strain, acquired novobiocin resistance at a high rate from the nonlysogenic strain. With most strains of phage type 88, there was no detectable transfer of resistance from lysogenic to nonlysogenic cells. Lysogenization with phage 188 of phage-sensitive strains conferred on the lysogenized cells the ability to acquire chromosome and...

  7. Prevalence of Staphylococcus aureus in Imported Fish and Correlations between Antibiotic Resistance and Enterotoxigenicity.

    Science.gov (United States)

    Obaidat, Mohammad M; Salman, Alaa E Bani; Lafi, Shawkat Q

    2015-11-01

    A total of 156 Staphylococcus aureus isolates were obtained from 330 imported fresh fish samples from three countries. Selective media were used for the isolation of S. aureus, and the isolates were confirmed by PCR. The isolates were tested for mecA gene, antibiotic resistance, and enterotoxin genes (sea, seb, sec, sed, see, seg, seh, and sei). Most isolates carried sea, seg, and sei genes, and seg-sei was the most frequent enterotoxin profile. About 88.5% of the S. aureus exhibited resistance to at least one antibiotic. High resistance to penicillin and ampicillin; low resistance to tetracycline, erythromycin, rifampin, and clindamycin; and very low resistance to cefotaxime, amoxicillin-clavulanic acid, gentamicin, and ciprofloxacin were exhibited by S. aureus from the three countries. In addition, some antibiotic resistance exhibited a strong correlation (P ≤ 0.01) with enterotoxigenicity in S. aureus. The study concluded that the large amount of globally traded fish increases the possibility of intercontinental transmission of enterotoxigenic and multidrug-resistant S. aureus through fish and highlights the potential influence of local fish handling and processing on consumer health worldwide. The introduction of periodic training in food safety and hygiene is essential to increase fish handlers' awareness of good hygienic practices in handling fish. These findings also enrich the ongoing debate about the risk of methicillin- and multidrug-resistant S. aureus as a foodborne pathogen compared with drug-susceptible S. aureus.

  8. Isolation and identification of antibiotic resistance genes in Staphylococcus aureus isolates from respiratory system infections in shahrekord, Iran

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    Maryam Reisi

    2014-07-01

    Full Text Available   Introduction : Staphylococcus aureus is considered as one of pathogenic agents in humans, that engages different body parts including respiratory system and causes to spend lots of costs and extending patient’s treatment period. This study which is performed to separate and investigate the pattern of antibiotic resistance in Staphylococcus aureus isolates from upper respiratory system infections in Shahrekord.   Materials and methods: This study was done by sectional-descriptive method On 200 suspicious persons to the upper respiratory system infections who were referred to the Imam Ali clinic in Shahrekord in 2012. After isolation of Staphylococcus aureus from cultured nose discharges, antibiotic resistance genes were identified by polymerase chain reaction (PCR by using defined primer pairs .   Results : Among 200 investigated samples in 60 cases (30% Staphylococcus aureus infection (by culturing and PCR method was determined. Isolates showed the lowest amount of antibiotic resistance to vancomycin (0.5% and the highest amount of resistance to the penicillin G and cefotaxime (100%. mecA gene (encoding methicillin resistance with frequency of 85.18% and aacA-D gene (encoding resistance to aminoglycosides with frequency of 28.33% showed the highest and lowest frequency of antibiotic resistance genes coding in Staphylococcus aureus isolates respectively .   Discussion and conclusion : Notable prevalence of resistant Staphylococcus aureus isolates in community acquired respiratory infections, recommend continuous control necessity to impede the spreading of these bacteria and their infections.  

  9. Antibiotic resistance and pathogenicity factors in Staphylococcus aureus isolated from mastitic Sahiwal cattle

    Indian Academy of Sciences (India)

    Ravinder Kumar; B R Yadav; R S Singh

    2011-03-01

    Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious problem in dairy animals suffering from mastitis. In the present study, the distribution of mastitic MRSA and antibiotic resistance was studied in 107 strains of S. aureus isolated from milk samples from 195 infected udders. The characterizations pathogenic factors (adhesin and toxin genes) and antibiotic susceptibility of isolates were carried out using gene amplification and disc diffusion assays, respectively. A high prevalence of MRSA was observed in the tested isolates (13.1%). The isolates were also highly resistant to antibiotics, i.e. 36.4% were resistant to streptomycin, 33.6% to oxytetracycline, 29.9% to gentamicin and 26.2% each to chloramphenicol, pristinomycin and ciprofloxacin. A significant variation in the expression of pathogenic factors (Ig, coa and clf) was observed in these isolates. The overall distribution of adhesin genes ebp, fib, bbp, fnbB, cap5, cap8, map and cna in the isolates was found to be 69.1, 67.2, 6.5, 20.5, 60.7, 26.1, 81.3 and 8.4%, respectively. The presence of fib, fnbB, bbp and map genes was considerably greater in MRSA than in methicillin-susceptible S. aureus (MSSA) isolates. The proportions of toxin genes, namely, hlb, seb, sec, sed, seg and sei, in the isolates were found to be 94.3, 0.9, 8.4, 0.9, 10.2 and 49.5%, respectively. The proportions of agr genes I, II, III and IV were found to be 39.2, 27.1, 21.5 and 12.1%, respectively. A few isolates showed similar antibiotic-resistance patterns, which could be due to identical strains or the dissemination of the same strains among animals. These findings can be utilized in mastitis treatment programmes and antimicrobials strategies in organized herds.

  10. Lab on a chip sensor for rapid detection and antibiotic resistance determination of Staphylococcus aureus.

    Science.gov (United States)

    Abeyrathne, Chathurika D; Huynh, Duc H; Mcintire, Thomas W; Nguyen, Thanh C; Nasr, Babak; Zantomio, Daniela; Chana, Gursharan; Abbott, Iain; Choong, Peter; Catton, Mike; Skafidas, Efstratios

    2016-03-21

    The Gram-positive bacterium, Staphylococcus aureus (S. aureus), is a major pathogen responsible for a variety of infectious diseases ranging from cellulitis to more serious conditions such as septic arthritis and septicaemia. Timely treatment with appropriate antibiotic therapy is essential to ensure clinical defervescence and to prevent further complications such as infective endocarditis or organ impairment due to septic shock. To date, initial antibiotic choice is empirical, using a "best guess" of likely organism and sensitivity- an approach adopted due to the lack of rapid identification methods for bacteria. Current culture based methods take up to 5 days to identify the causative bacterial pathogen and its antibiotic sensitivity. This paper provides proof of concept for a biosensor, based on interdigitated electrodes, to detect the presence of S. aureus and ascertain its sensitivity to flucloxacillin rapidly (within 2 hours) in a cost effective manner. The proposed method is label-free and uses non-faradic measurements. This is the first study to successfully employ interdigitated electrodes for the rapid detection of antibiotic resistance. The method described has important potential outcomes of faster definitive antibiotic treatment and more rapid clinical response to treatment.

  11. Metabolic profiling for detection of Staphylococcus aureus infection and antibiotic resistance.

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    Henrik Antti

    Full Text Available Due to slow diagnostics, physicians must optimize antibiotic therapies based on clinical evaluation of patients without specific information on causative bacteria. We have investigated metabolomic analysis of blood for the detection of acute bacterial infection and early differentiation between ineffective and effective antibiotic treatment. A vital and timely therapeutic difficulty was thereby addressed: the ability to rapidly detect treatment failures because of antibiotic-resistant bacteria. Methicillin-resistant Staphylococcus aureus (MRSA and methicillin-sensitive S. aureus (MSSA were used in vitro and for infecting mice, while natural MSSA infection was studied in humans. Samples of bacterial growth media, the blood of infected mice and of humans were analyzed with combined Gas Chromatography/Mass Spectrometry. Multivariate data analysis was used to reveal the metabolic profiles of infection and the responses to different antibiotic treatments. In vitro experiments resulted in the detection of 256 putative metabolites and mice infection experiments resulted in the detection of 474 putative metabolites. Importantly, ineffective and effective antibiotic treatments were differentiated already two hours after treatment start in both experimental systems. That is, the ineffective treatment of MRSA using cloxacillin and untreated controls produced one metabolic profile while all effective treatment combinations using cloxacillin or vancomycin for MSSA or MRSA produced another profile. For further evaluation of the concept, blood samples of humans admitted to intensive care with severe sepsis were analyzed. One hundred thirty-three putative metabolites differentiated severe MSSA sepsis (n = 6 from severe Escherichia coli sepsis (n = 10 and identified treatment responses over time. Combined analysis of human, in vitro, and mice samples identified 25 metabolites indicative of effective treatment of S. aureus sepsis. Taken together, this

  12. Antibiotic resistant pattern of methicillin resistant and sensitive Staphylococcus aureus isolated from patients durining 2009-2010, Ahvaz, Iran.

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    N Parhizgari

    2013-12-01

    Full Text Available Abstract Background & aim: Staphylococcus aureus is one of the most important nosocomial infecting agents resistant to commonly used antibiotics. Nowadays, methicillin-resistant S. aureus (MRSA is considered one of the main causes of nosocomial infections. The aim of this study was to identify the antibiotic resistance pattern of methicicllin- resistant and susceptible strains in Ahwaz, Iran. Methods: In the present cross - sectional study, a number of 255 clinically suspected cases of Staphylococcus aureus were collected during a 19 month period. The bacteria were investigated using standard biochemical tests such as catalase, mannitol fermentation, coagulase and Dnase. Sensitive strains were confirmed by disk diffusion method compared to commonly used antibiotics. The collected data were analyzed using descriptive statistical tests. Results: of 255 suspected cases, 180 were confirmed as S.aureus, a total of 59 strains of S. aureus (2/37 percent were resistant to methicillin. Resistance to S. aureus strains resistant to methicillin included: chloramphenicol (3.38%, rifampin (45.76%, norfloxacin (89.83%, gentamicin (89.83%, ciprofloxacin, (91.52%, azithromycin, (88.13%, cotrimoxazole (86.44% and all isolates strains were sensitive to vancomycin and nitrofurantoin. A total of 10 different patterns of antibiotic resistance in methicillin-resistant Staphylococcus aureus strains were identified. Conclusion: Expression of new resistance factor in nosocomial infection is one of the major challenges in treating these infections. This study showed a high prevalence of resistance against some class of antibiotics in MRSA isolated from Imam Khomeini and Golestan hospital of Ahwaz, Iran. Key words: Nosocomial infection, Methicillin Resistant Staphylococcus aureus (MRSA, Antibiotic Resistant Pattern

  13. Insights on Virulence and Antibiotic Resistance: A Review of the Accessory Genome of Staphylococcus aureus.

    Science.gov (United States)

    Shittu, Adebayo O; Udo, Edet E; Lin, Johnson

    2007-09-01

    Staphylococcus aureus continues to be a serious health problem worldwide due to its intrinsic nature of virulence, ability to cause a wide array of infection, and its capacity to develop resistance to a number of antibiotics. The S aureus genome has continually evolved through both mutation and acquisition of exogenous genes, leading to the emergence of antibiotic-resistant strains with the ability for clonal dissemination across nations and continents. Methicillin-resistant S aureus (MRSA) is one of the most commonly identified antibiotic-resistant pathogens in the hospital and community settings with substantial mortality and morbidity. This review examines the accessory genome of 8 sequenced S aureus strains regarding the variety of virulence factors and mechanisms of antibiotic resistance. The remarkable nature of this organism to acquire and disseminate an array of mobile genetic elements (MBEs) through horizontal gene transfer illustrates the mechanisms for evolution and its fitness level in the face of constant environmental challenges. The relative ease of transfer of genetic materials, especially antibiotic-resistant genes, across staphylococcal species indicates that there is a potential pandemic problem in the hospital and community environment.

  14. Molecular Characterization of Staphylococcus aureus Isolated from Meat and Their Antibiotic Resistance Profiles

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    Ziad W Jaradat

    2014-01-01

    Full Text Available The aims of this study were to characterize S. aureus isolates from different meat sources in Jordan and study their genetic relationship using PCR-RFLP in addition to their antibiotic resistance profiles. Thirty S. aureus isolates were identified and confirmed by PCR techniques. The isolates from goat and camel meats were sensitive to the majority of the tested antibiotics. Plasmid profiling revealed that 26 isolates contained at least one plasmid with no correlation between the number of plasmids and the resistance profiles. PCR-RFLP of the coagulase gene (coa classified the isolates to several clusters upon digestion with Alu I or Cfo I restriction enzymes. This study concluded that the 30 S. aureus isolates were genetically diverse and comprised heterogeneous population with 7 genotypes at both 33.1 and 51.2 similarity levels.

  15. Investigation of the antibiotic resistance and biofilm-forming ability of Staphylococcus aureus from subclinical bovine mastitis cases.

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    Aslantaş, Özkan; Demir, Cemil

    2016-11-01

    A total of 112 Staphylococcus aureus isolates obtained from subclinical bovine mastitis cases were examined for antibiotic susceptibility and biofilm-forming ability as well as genes responsible for antibiotic resistance, biofilm-forming ability, and adhesin. Antimicrobial susceptibility of the isolates were determined by disk diffusion method. Biofilm forming ability of the isolates were investigated by Congo red agar method, standard tube method, and microplate method. The genes responsible for antibiotic resistance, biofilm-forming ability, and adhesion were examined by PCR. Five isolates (4.5%) were identified as methicillin-resistant Staph. aureus by antibiotic susceptibility testing and confirmed by mecA detection. The resistance rates to penicillin, ampicillin, tetracycline, erythromycin, trimethoprim-sulfamethoxazole, enrofloxacin, and amoxicillin-clavulanic acid were 45.5, 39.3, 33, 26.8, 5.4, 0.9, and 0.9%, respectively. All isolates were susceptible against vancomycin and gentamicin. The blaZ (100%), tetK (67.6%), and ermA (70%) genes were the most common antibiotic-resistance genes. Using Congo red agar, microplate, and standard tube methods, 70.5, 67, and 62.5% of the isolates were found to be biofilm producers, respectively. The percentage rate of icaA, icaD, and bap genes in Staph. aureus isolates were 86.6, 86.6, and 13.4%, respectively. The adhesion molecules fnbA, can, and clfA were detected in 87 (77.7%), 98 (87.5%), and 75 (70%) isolates, respectively. The results indicated that Staph. aureus from sublinical bovine mastitis cases were mainly resistant to β-lactams and, to a lesser extent, to tetracycline and erythromycin. Also, biofilm- and adhesion-related genes, which are increasingly accepted as an important virulence factor in the pathogenesis of Staph. aureus infections, were detected at a high rate.

  16. Partial Sequencing of 16S rRNA Gene of Selected Staphylococcus aureus Isolates and its Antibiotic Resistance

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    Harsi Dewantari Kusumaningrum

    2016-08-01

    Full Text Available The choice of primer used in 16S rRNA sequencing for identification of Staphylococcus species found in food is important. This study aimed to characterize Staphylococcus aureus isolates by partial sequencing based on 16S rRNA gene employing primers 16sF, 63F or 1387R. The isolates were isolated from milk, egg dishes and chicken dishes and selected based on the presence of sea gene that responsible for formation of enterotoxin-A. Antibiotic susceptibility of the isolates towards six antibiotics was also tested. The use of 16sF resulted generally in higher identity percentage and query coverage compared to the sequencing by 63F or 1387R. BLAST results of all isolates, sequenced by 16sF, showed 99% homology to complete genome of four S. aureus strains, with different characteristics on enterotoxin production and antibiotic resistance. Considering that all isolates were carrying sea gene, indicated by the occurence of 120 bp amplicon after PCR amplification using primer SEA1/SEA2,  the isolates were most in agreeing to S. aureus subsp. aureus ST288. This study indicated that 4 out of 8 selected isolates were resistant towards streptomycin. The 16S rRNA gene sequencing using 16sF is useful for identification of S. aureus. However, additional analysis such as PCR employing specific gene target, should give a valuable supplementary information, when specific characteristic is expected.

  17. Streptokinase Treatment Reverses Biofilm-Associated Antibiotic Resistance in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Jørgensen, Nis Pedersen; Zobek, Natalia; Dreier, Cindy;

    2016-01-01

    Biofilms formed by Staphylococcus aureus is a serious complication to the use of medical implants. A central part of the pathogenesis relies on S. aureus’ ability to adhere to host extracellular matrix proteins, which adsorb to medical implants and stimulate biofilm formation. Being coagulase...

  18. Staphylococcus aureus bacteraemia in a tropical setting: patient outcome and impact of antibiotic resistance.

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    Emma K Nickerson

    Full Text Available BACKGROUND: Most information on invasive Staphylococcus aureus infections comes from temperate countries. There are considerable knowledge gaps in epidemiology, treatment, drug resistance and outcome of invasive S. aureus infection in the tropics. METHODS: A prospective, observational study of S. aureus bacteraemia was conducted in a 1000-bed regional hospital in northeast Thailand over 1 year. Detailed clinical data were collected and final outcomes determined at 12 weeks, and correlated with antimicrobial susceptibility profiles of infecting isolates. PRINCIPAL FINDINGS: Ninety-eight patients with S. aureus bacteraemia were recruited. The range of clinical manifestations was similar to that reported from temperate countries. The prevalence of endocarditis was 14%. The disease burden was highest at both extremes of age, whilst mortality increased with age. The all-cause mortality rate was 52%, with a mortality attributable to S. aureus of 44%. Methicillin-resistant S. aureus (MRSA was responsible for 28% of infections, all of which were healthcare-associated. Mortality rates for MRSA and methicillin-susceptible S. aureus (MSSA were 67% (18/27 and 46% (33/71, respectively (p = 0.11. MRSA isolates were multidrug resistant. Only vancomycin or fusidic acid would be suitable as empirical treatment options for suspected MRSA infection. CONCLUSIONS: S. aureus is a significant pathogen in northeast Thailand, with comparable clinical manifestations and a similar endocarditis prevalence but higher mortality than industrialised countries. S. aureus bacteraemia is frequently associated with exposure to healthcare settings with MRSA causing a considerable burden of disease. Further studies are required to define setting-specific strategies to reduce mortality from S. aureus bacteraemia, prevent MRSA transmission, and to define the burden of S. aureus disease and emergence of drug resistance throughout the developing world.

  19. Antibiotic resistance of Staphylococcus aureus strains isolated from fish processing factory workers

    OpenAIRE

    1988-01-01

    One hundred and twenty two strains of Staphylococcus aureus isolated from throats and palms of 39 workers from 6 fish processing factories situated in and around Cochin were tested for their sensitivity to nine commonly used antibiotics-ampicillin, chloramphenicol, erythromycin, kanamycin, neomycin, penicillin, polymyxin-B, streptomycin and tetracycline. Highest percentage of resistance was observed towards ampicillin followed by penicillin i.e. 64.75% and 59.84%. Resistance towards other ant...

  20. PCR-based identification of methicillin-resistant Staphylococcus aureus strains and their antibiotic resistance profiles

    Institute of Scientific and Technical Information of China (English)

    Abazar Pournajaf; Abdollah Ardebili; Leyla Goudarzi; Mahmoud Khodabandeh; Tahmineh Narimani; Hassan Abbaszadeh

    2014-01-01

    Objective: To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification. Methods: A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates.Results:activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA- positive in the PCR assay. Among antibiotics used in our study, penicillin showed the least anti-staphylococcal Conclusions: This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic.

  1. Antibiotic Resistance in Staphylococcus aureus and Coagulase Negative Staphylococci Isolated from Goats with Subclinical Mastitis

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    Salvatore Virdis

    2010-01-01

    Full Text Available Antimicrobial resistance patterns and gene coding for methicillin resistance (mecA were determined in 25 S. aureus and 75 Coagulase Negative Staphylococci (CNS strains isolates from half-udder milk samples collected from goats with subclinical mastitis. Fourteen (56.0% S. aureus and thirty-one (41.3% CNS isolates were resistant to one or more antimicrobial agents. S. aureus showed the highest resistance rate against kanamycin (28.0%, oxytetracycline (16.0%, and ampicillin (12.0%. The CNS tested were more frequently resistant to ampicillin (36.0% and kanamycin (6.7%. Multiple antimicrobial resistance was observed in eight isolates, and one Staphylococcus epidermidis was found to be resistant to six antibiotics. The mecA gene was not found in any of the tested isolates. Single resistance against β-lactamics or aminoglicosides is the most common trait observed while multiresistance is less frequent.

  2. Streptokinase Treatment Reverses Biofilm-Associated Antibiotic Resistance in Staphylococcus aureus

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    Nis Pedersen Jørgensen

    2016-09-01

    Full Text Available Biofilms formed by Staphylococcus aureus is a serious complication to the use of medical implants. A central part of the pathogenesis relies on S. aureus’ ability to adhere to host extracellular matrix proteins, which adsorb to medical implants and stimulate biofilm formation. Being coagulase positive, S. aureus furthermore induces formation of fibrin fibers from fibrinogen in the blood. Consequently, we hypothesized that fibrin is a key component of the extracellular matrix of S. aureus biofilms under in vivo conditions, and that the recalcitrance of biofilm infections can be overcome by combining antibiotic treatment with a fibrinolytic drug. We quantified S. aureus USA300 biofilms grown on peg-lids in brain heart infusion (BHI broth with 0%–50% human plasma. Young (2 h and mature (24 h biofilms were then treated with streptokinase to determine if this lead to dispersal. Then, the minimal biofilm eradication concentration (MBEC of 24 h old biofilms was measured for vancomycin and daptomycin alone or in combination with 10 µg/mL rifampicin in the presence or absence of streptokinase in the antibiotic treatment step. Finally, biofilms were visualized by confocal laser scanning microscopy. Addition of human plasma stimulated biofilm formation in BHI in a dose-dependent manner, and biofilms could be partially dispersed by streptokinase. The biofilms could be eradicated with physiologically relevant concentrations of streptokinase in combination with rifampicin and vancomycin or daptomycin, which are commonly used antibiotics for treatment of S. aureus infections. Fibronolytic drugs have been used to treat thromboembolic events for decades, and our findings suggest that their use against biofilm infections has the potential to improve the efficacy of antibiotics in treatment of S. aureus biofilm infections.

  3. Streptokinase Treatment Reverses Biofilm-Associated Antibiotic Resistance in Staphylococcus aureus

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    Jørgensen, Nis Pedersen; Zobek, Natalia; Dreier, Cindy; Haaber, Jakob; Ingmer, Hanne; Larsen, Ole Halfdan; Meyer, Rikke L.

    2016-01-01

    Biofilms formed by Staphylococcus aureus is a serious complication to the use of medical implants. A central part of the pathogenesis relies on S. aureus’ ability to adhere to host extracellular matrix proteins, which adsorb to medical implants and stimulate biofilm formation. Being coagulase positive, S. aureus furthermore induces formation of fibrin fibers from fibrinogen in the blood. Consequently, we hypothesized that fibrin is a key component of the extracellular matrix of S. aureus biofilms under in vivo conditions, and that the recalcitrance of biofilm infections can be overcome by combining antibiotic treatment with a fibrinolytic drug. We quantified S. aureus USA300 biofilms grown on peg-lids in brain heart infusion (BHI) broth with 0%–50% human plasma. Young (2 h) and mature (24 h) biofilms were then treated with streptokinase to determine if this lead to dispersal. Then, the minimal biofilm eradication concentration (MBEC) of 24 h old biofilms was measured for vancomycin and daptomycin alone or in combination with 10 µg/mL rifampicin in the presence or absence of streptokinase in the antibiotic treatment step. Finally, biofilms were visualized by confocal laser scanning microscopy. Addition of human plasma stimulated biofilm formation in BHI in a dose-dependent manner, and biofilms could be partially dispersed by streptokinase. The biofilms could be eradicated with physiologically relevant concentrations of streptokinase in combination with rifampicin and vancomycin or daptomycin, which are commonly used antibiotics for treatment of S. aureus infections. Fibronolytic drugs have been used to treat thromboembolic events for decades, and our findings suggest that their use against biofilm infections has the potential to improve the efficacy of antibiotics in treatment of S. aureus biofilm infections. PMID:27681928

  4. Characterization of SCCmec types, antibiotic resistance, and toxin gene profiles of Staphylococcus aureus strains.

    Science.gov (United States)

    Szczuka, Ewa; Grabska, Katarzyna; Trawczyński, Krzysztof; Bosacka, Karolina; Kaznowski, Adam

    2013-09-01

    Methicillin-resistant Staphylococcus aureus (MRSA) causes serious nosocomial and community acquired infections. Resistance to methicillin is mediated by the mecA gene, which is inserted in a mobile genetic element called staphylococcal cassette chromosome mec (SCCmec). We determined the SCCmec types, the occurrence of genes encoding toxic shock syndrome toxin (tst), exfoliative toxin (eta, etb), Panton-Valentine leukocidin (pvl) as well as antibiotic susceptibility of these isolates. Among 65 hospital-acquired methicillin-resistant S. aureus (HA-MRSA) strains, SCCmec types II, III and IV were identified. Type III SCCmec was the most prevalent (62%), followed by mec types II (24%) and IV (14%). Four community acquired methicillin-resistant S. aureus (CA-MRSA) strains carried SCCmec type IV and were pvl-positive. The most prevalent gene among HA-MRSA was pvl. The toxic shock syndrome toxin and exfoliative toxin genes were found only in hospital-acquired methicillin-resistant S. aureus. The results of this study demonstrate that the SCCmec type III is predominant among strains recovered from hospitalized patients with infections and that these strains were resistant to many antibiotics used in the treatment of staphylococcal infections.

  5. Bacterial Contamination and Antibiotic Resistance of Staphylococcus Aureus Isolated from Automated Teller Machine

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    Moshtaghi, H. (PhD

    2015-05-01

    Full Text Available Background and Objective: Automated Teller Machine (ATMs is likely to be contaminated with various microorganisms specially pathogen germs. This may be due to their exposure to dust and their vast dermal contact with multiple users. This study investigated the bacterial contamination on the keyboard of ATMs and drug resistance of the bacteria isolated from them. Material and Methods: the keyboards of 50 ATMs in Shahrekord city, Iran, were examined from October 2012 to February 2013. The sterile swab sticks moistened with Triptose soy broth were used for sampling. The bacteriological tests used were culture, biochemical test and agar disk diffusion method for antibiogram. Results: All the samples were found to be contaminated with Coagulase negative staphylococci (57.54%, Bacillus species (21.92%, Staphylococcus aureus (19.18% and coliform bacteria (1.36%. The resistance of Staphylococcus aureus was 92.8% to penicillin, 85.7% to amoxicilin، 71.4% to ampicillin, 57.1% to nytrofuran, 50% to tetracycline, 42.8% to erythromycin, 42.8% to gentamycin, 14.2 % to ciprofloxacin, 7.1% to trimethoprim and sulfamtuksazul. All species were susceptible to, ofloxacine, chloramphenicol, clindamycin, tobramycin, vancomycin and cefotaxime. Conclusion: given the presence of pathogens on ATMs and their role in transferring the contamination, we recommend considering personal hygiene and periodically disinfecting the keyboards to reduce contamination

  6. Antibiotic-resistance Staphylococcus aureus isolated from cow’s milk in the Hawassa area, South Ethiopia

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    Daka Deresse

    2012-09-01

    Full Text Available Abstract Background Quarter milk samples from cows were examined to determine the prevalence of Staphylococcus aureus (SA and different antibiotic resistant pattern were determined in a cross-sectional study design. Objective The objective of this study was to isolate Staphylococcus aureus from samples of cow’s milk obtained from Hawassa area and to determine their antibiotic susceptibility patterns. Method A total of 160 milk (CCP1-CCP5 samples were collected and screened for the presence of S. aureus. Gram staining, oxidase, catalase, DNase, haemolysis and coagulase tests were employed for bacterial identification. Results All the samples were contaminated with S. aureus. A total of 78 S. aureus isolates were obtained during this study. The levels of contamination with S. aureus were higher in milk obtained from CCP1, CCP2, CCP3, CCP4 and CCP5 at Hawassa area farms (18.0%, 25.6%, 27.0%, 21.8% and 7.7% respectively. A large percentage of the S. aureus isolates (25.6% and 27.0% were from CCP2 and CCP3. All strains were resistant to Penicillin G (PG (10 μg, Ampicillin (AP (10 μg, Amoxicillin-Clavulanic acid (AC (30 μg, Ciprofloxacin (CIP (5 μg, Erythromycin (E (15 μg, Ceftriaxone (CRO (30 μg, Trimethoprime-Sulfamethoxazole (TMP-SMZ (25 μg Oxacillin (Ox (1 μg and Vancomycin (V (30 μg, 67.9%, 70.9%, 30.9%, 0%, 32.1%, 23.1%, 7.7%, 60.3% and 38.5% respectively. Conclusion The proportion of isolates resistant to CIP, TMP-SMZ, CRO, AC, E and V were low compared to AP, PG and Ox. S. aureus is normally resident in humans; therefore, the S. aureus present in the cow’s milk may have resulted from transmission between the two species, emphasizing the need to improve sanitary conditions in the milking environment.

  7. Characterization of a Bacteriophage-Derived Murein Peptidase for Elimination of Antibiotic-Resistant Staphylococcus aureus.

    Science.gov (United States)

    Keary, Ruth; Sanz-Gaitero, Marta; van Raaij, Mark J; O'Mahony, Jim; Fenton, Mark; McAuliffe, Olivia; Hill, Colin; Ross, R Paul; Coffey, Aidan

    2016-01-01

    Staphylococcus aureus is a major cause of infection in humans and animals, causing a wide variety of diseases, from local inflammations to fatal sepsis. The bacterium is commonly multi-drug resistant and thus many front-line antibiotics have been rendered ineffective for treating such infections. Research on murein/peptidoglycan hydrolases, derived from bacterial viruses (bacteriophages), has demonstrated that such proteins are attractive candidates for development as novel antibacterial agents for combatting Gram-positive pathogens. Here we review the research produced to-date on the bacteriophage-derived CHAPK murein peptidase. Initially, we sequenced and annotated the genome of anti-staphylococcal bacteriophage K and cloned the gene for the bacteriophage endolysin, a murein hydrolase which plays a role in cell killing during the bacteriophage life cycle. An highly active domain of the enzyme, a cysteine, histidine-dependent amido hydrolase/peptidase (CHAPK), was cloned, overexpressed in E. coli and purified. This CHAPK enzyme was demonstrated to rapidly lyse several strains of methicillin resistant S. aureus and both disrupted and prevented the formation of a staphylococcal biofilm. The staphylolytic activity of the peptidase was demonstrated in vivo using a mouse model, without adverse effects on the animals. The crystal structure of the enzyme was elucidated, revealing a calcium ion close to the active site. Site-directed mutagenesis indicated that this calcium ion is involved in the catalytic mechanism of the enzyme. The crystal structure of this enzyme is a valuable source of information for efficient engineering of this and similar CHAP-domain-containing proteins. Overall, the data collected to date on CHAPK has demonstrated its strong potential as a novel therapeutic candidate for treatment of staphylococcal infections and has provided us with insight into the fundamental enzymatic mechanisms of CHAP domain-containing peptidoglycan hydrolases.

  8. Metabolic activity, urease production, antibiotic resistance and virulence in dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus

    Science.gov (United States)

    Vandecandelaere, Ilse; Van Nieuwerburgh, Filip; Deforce, Dieter

    2017-01-01

    In this paper, the metabolic activity in single and dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus isolates was investigated. Our results demonstrated that there was less metabolic activity in dual species biofilms compared to S. aureus biofilms. However, this was not observed if S. aureus and S. epidermidis were obtained from the same sample. The largest effect on metabolic activity was observed in biofilms of S. aureus Mu50 and S. epidermidis ET-024. A transcriptomic analysis of these dual species biofilms showed that urease genes and genes encoding proteins involved in metabolism were downregulated in comparison to monospecies biofilms. These results were subsequently confirmed by phenotypic assays. As metabolic activity is related to acid production, the pH in dual species biofilms was slightly higher compared to S. aureus Mu50 biofilms. Our results showed that S. epidermidis ET-024 in dual species biofilms inhibits metabolic activity of S. aureus Mu50, leading to less acid production. As a consequence, less urease activity is required to compensate for low pH. Importantly, this effect was biofilm-specific. Also S. aureus Mu50 genes encoding virulence-associated proteins (Spa, SplF and Dps) were upregulated in dual species biofilms compared to monospecies biofilms and using Caenorhabditis elegans infection assays, we demonstrated that more nematodes survived when co-infected with S. epidermidis ET-024 and S. aureus mutants lacking functional spa, splF or dps genes, compared to nematodes infected with S. epidermidis ET-024 and wild- type S. aureus. Finally, S. epidermidis ET-024 genes encoding resistance to oxacillin, erythromycin and tobramycin were upregulated in dual species biofilms and increased resistance was subsequently confirmed. Our data indicate that both species in dual species biofilms of S. epidermidis and S. aureus influence each other’s behavior, but additional studies are required necessary to elucidate the exact

  9. Prevalence of Staphylococcus aureus and antibiotic resistance in children with atopic dermatitis in Arar, Saudi Arabia

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    Dhaifallah A. Alenizi

    2014-01-01

    Conclusion: 65% of Saudi children with atopic dermatitis are colonized with S. aureus in their skin lesions. The rate of colonization is affected by severity of the disease and by the age of the patient.

  10. Analysis of the Clinical Characteristics and Antibiotics Resistance of Community-acquired Methicillin-resistant Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    章税锋; 徐志江; 王林峰

    2004-01-01

    The purpose of this investigation is to study the clinical characteristics of infections by community-acquired methicillin-resistant Staphylococcus aureus (MRSA) and the condition of antibiotics resistance of the clinical isolates in order to guide for the rational use of antibiotics. With the clinical isolates from cases of hospital-acquired MRSA at the same period as contro|s, the clinical characteristics of infections by community-acquired MRSA in Hangzhou area and the pattern of non-β-lactamase antibiotics resistance were determined in this study. It was found that the average age of patients with community-acquired MRSA infections was 30.89 + 13.3, in comparison with those of the hospital-acquired patients of 56.0 + 11.8, appearing to be younger than those of the latter, and the former showing no any basic illness. Both of the former and the latter were sensitive to vancomycin ( 100% vs 100% ), and they had the same degrees of sensitivity to rifampicin, fosfomycin, and STM/TMP (86.8%vs88.1%, P>0.05; 81.6% vs 82.9%, P>0.05; and 52.6% vs 61.9%, P>0.05, respectively). The former was more sensitive to netimycin, chndamycin, erythromycin and minocycline than those of the latter (73.7% vs50.5%, P<0.01; 60.5% vs45.7%, P<0.05; 28.9% vs 11.4%, P<0.01; and81.6% vs58.6%, P<0.01 respectively). Meanwhile, the incidence of multi-resistant strain of isolates in the former was significantly lowerthan that of the latter (31.6% vs 81.0%, P < 0.01). In conclusion, it appears that the strains of clinical isolates isolated from patients with the community-acquired MRSA infections show different clinical characteristics and antimicrobial susceptibility in comparison with those of the hospital-acquired cases of infection, and this necessitates an alteration in the chemotherapy of infections suspected to be caused by community-acquired MRSA.

  11. Detection of Antibiotic Resistant Staphylococcus aureus from Milk: A Public Health Implication.

    Science.gov (United States)

    Akindolire, Muyiwa Ajoke; Babalola, Olubukola Oluranti; Ateba, Collins Njie

    2015-08-25

    The aim of this study was to investigate the occurrence, antibiotic susceptibility profiles, and virulence genes determinants of S. aureus isolated from milk obtained from retail outlets of the North-West Province, South Africa. To achieve this, 200 samples of raw, bulk and pasteurised milk were obtained randomly from supermarkets, shops and some farms in the North-West Province between May 2012 and April 2013. S. aureus was isolated and positively identified using morphological (Gram staining), biochemical (DNase, catalase, haemolysis and rapid slide agglutination) tests, protein profile analysis (MALDI-TOF mass spectrometry) and molecular (nuc specific PCR) methods. The antimicrobial resistance profiles of the isolates were determined using the phenotypic agar diffusion method. Genes encoding enterotoxins, exfoliative toxins and collagen adhesins were also screened using PCR. Among all the samples examined, 30 of 40 raw milk samples (75%), 25 of 85 bulk milk samples (29%) and 10 of 75 pasteurised milk samples (13%) were positive for S. aureus. One hundred and fifty-six PCR-confirmed S. aureus isolates were obtained from 75 contaminated milk samples. A large proportion (60%-100%) of the isolates was resistant to penicillin G, ampicillin, oxacillin, vancomycin, teicoplanin and erythromycin. On the contrary, low level resistance (8.3%-40%) was observed for gentamicin, kanamycin and sulphamethoxazole. Methicillin resistance was detected in 59% of the multidrug resistant isolates and this was a cause for concern. However, only a small proportion (20.6%) of these isolates possessed PBP2a which codes for Methicillin resistance in S. aureus. In addition, 32.7% of isolates possessed the sec gene whereas the sea, seb sed, see, cna, eta, etb genes were not detected. The findings of this study showed that raw, bulk and pasteurised milk in the North-West Province is contaminated with toxigenic and multi-drug resistant S. aureus strains. There is a need to implement

  12. Quantitative differences in antibiotic resistance between methicillin-resistant and methicillin-susceptible Staphylococcus aureus strains isolated in Hungary, Austria and Macedonia.

    Science.gov (United States)

    Horvath, A; Rozgonyi, F; Pesti, N; Kocsis, E; Malmos, G; Kristof, K; Nagy, K; Lagler, H; Presterl, E; Stich, K; Gattringer, R; Kotolacsi, G; Cekovska, Z; Graninger, W

    2010-08-01

    The aim of this study was to compare the quantitative susceptibility of methicillin-resistant and -susceptible Staphylococcus aureus (MRSA and MSSA) strains from three European countries to nine antistaphylococcal agents. The antibiotic susceptibility of 274 MRSA and 284 MSSA strains from Hungary, Austria and macedonia was tested by the broth microdilution method. The clonal relationship of strains was determined by pulsed-field gel electrophoresis. Intermediate susceptibility to vancomycin appeared in Macedonian MRSA strains. Macedonian MRSA strains had high-level amikacin and gentamicin resistance. MSSA strains generally were susceptible to all drugs at minimum inhibitory concentrations (MIC(50)) except for gentamicin resistance in Macedonian strains. In Hungary and Austria a common antibiotic resistance phenotype of MRSA predominated, while in macedonia three other phenotypes were also prevalent. Geographical differences in the resistance of S. aureus are still high. Since resistance levels of MRSA and MSSA strains differ extensively, they should be considered separately for antibiotic resistance analysis.

  13. Streptokinase Treatment Reverses Biofilm-Associated Antibiotic Resistance in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Jørgensen, Nis Pedersen; Zobek, Natalia; Dreier, Cindy

    2016-01-01

    by combining antibiotic treatment with a fibrinolytic drug. We quantified S. aureus USA300 biofilms grown on peg-lids in brain heart infusion (BHI) broth with 0%–50% human plasma. Young (2 h) and mature (24 h) biofilms were then treated with streptokinase to determine if this lead to dispersal. Then......, the minimal biofilm eradication concentration (MBEC) of 24 h old biofilms was measured for vancomycin and daptomycin alone or in combination with 10 µg/mL rifampicin in the presence or absence of streptokinase in the antibiotic treatment step. Finally, biofilms were visualized by confocal laser scanning...... or daptomycin, which are commonly used antibiotics for treatment of S. aureus infections. Fibronolytic drugs have been used to treat thromboembolic events for decades, and our findings suggest that their use against biofilm infections has the potential to improve the efficacy of antibiotics in treatment of S...

  14. Frequency and Antibiotic Resistance Pattern in Staphylococcus aureus Strains Isolated from Clinical Samples of Tehran’s Araad Hospital in 2007-2011

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    Hamed Molaabaszadeh

    2014-01-01

    Full Text Available ABSTRACT Background and objective: Todays, the resistance to antibiotics among of pathogen bacteria is one of the main concerns of doctors all around the world, with consideration to different reports about Staphylococcus aureus bacteria’s sensitivity, this study was done to examine the pattern of sensitivity and antibiotic resistance of Staphylococcus aureus strains collected from clinical samples of patients hospitalized in Tehran’s Araad hospital. Materials and methods: In this descriptive examination, after extracting Staphylococcus aureus derivations from clinical samples (urine, catheter, phlegm, wound, bronchial and blood, their sensitivity was measured using standard Kirby-Bauer test, in contract with following antibiotics Amikacin, Ciprofloxacin, Vancomycin, Imipenem, Sulfametoxazole Trimetoprime, Tetracycline, Oxacillin, Ceftriaxone and Penicillin. Results: In this study 260 samples of Staphylococcus aureus isolated from clinical specimens in three years. The most sensivity was to Vancomycin and the most resistance was to Penicillin and Oxacillin. Conclusion: The results of this study are indicating that Staphylococcus aureus strains resistance has increased against Penicillin and Oxacillin; presumably it is due to excessive consumption of these antibiotics. It is obvious that, with regard to increasing consumption of antibiotics and consequently, augmentation of antibacterial resistance, control of this resistance factor is necessary and inevitable, so it is recommended to avoid unnecessary usage of antibiotics.

  15. The Relationship Between Antibiotic Resistance and Agr Type in Methicillin-Resistant Staphylococcus aureus (MRSA Isolated From Burn Wound of Hospitalized Patient in Tehran

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    Mohammad Sadegh Vaziri

    2015-12-01

    Full Text Available Introduction: Staphylococcus aureus is the major cause of hospital and community-acquired infections. This bacterium possesses an accessory gene regulator (agr that plays role in colonization, expression of virulence factors and antibiotic resistance. It’s four major polypeptide with variable sequences lead to at least four agr type in S. aureus.The aim of this study was to determine the relationship between the antibiogram patterns with agr type of clinical S. aureus.Methods: Detection of methicillin-resistant Staphylococcus aureus (MRSA from burn wounds was performed by phenotypic and genotypic profiles. The antibiotics resistance pattern was determined by disk agar diffusion (Tigecycline (TGC, Ciprofloxacin(CIP, Erythromycin(E, Cloxacillin(CX, Clindamycin(CD, Imipenem(IMI, Co-trimoxazole(SXT, Kanamycin(K, Teicoplanin(TEC, Gentamicin(GM, Mupirocin(MUP, Ceftriaxone (CTR. The agr typing by PCR-RFLP method using the Restriction endonuclease ScaI was performed and spss19 was used for data analysis.Results: The total of 76 MRSA isolates was studied. The agr type distribution was 75.6% Type I, 8.2% Type II, 5.4% Type III, 10.8% type IV. The most antibiotics resistant agr type belongs to the type I. There was no significance relationship between every agr type and antibiotics but only a statistically significant association exist between CX, E, CTR, SXT, GM, CIP antibiotics and all agr types (P<0.05.Conclusion: There was no significance relationship between every agr type and antibiotics but significant relationship observed between resistance to some antibiotics with all agr types could be related to the number and source of isolated bacteria or extra use of these antibiotics. By considering that agr locus belongs to upstream genes so it may use the Quorum Sensing (QS system to induce the most drug resistance.

  16. Toward an Alternative Therapeutic Approach for Skin Infections: Antagonistic Activity of Lactobacilli Against Antibiotic-Resistant Staphylococcus aureus and Pseudomonas aeruginosa.

    Science.gov (United States)

    Hafez, Mohamed M; Maghrabi, Ibrahim A; Zaki, Noha M

    2013-09-01

    The wide spread of antimicrobial resistance has urged the need of alternative therapeutic approach. In this context, probiotic lactobacilli have been reported for the prevention and treatment of many gastrointestinal and urogenital infections. However, very little is known about their antagonistic activity against skin pathogens. Accordingly, the present study aimed to investigate the potential of lactobacilli to interfere with pathogenesis features of two antibiotic-resistant skin pathogens, namely methicillin-resistant Staphylococcus aureus and multiple-resistant Pseudomonas aeruginosa. A total of 49 lactobacilli were recovered, identified and tested for their antagonistic activities against the aforementioned pathogens. Of these, eight isolates were capable of blocking the adherence of pathogens to mammalian cells independent of the skin pathogen tested or model adopted. Moreover, three Lactobacillus isolates (LRA4, LC2 and LR5) effectively prevented the pathogen internalization into epithelial cells in addition to potentiating phagocyte-mediated pathogen killing. Interestingly, the lactobacilli LC2, LF9 and LRA4 markedly inhibited the growth of P. aeruginosa and S. aureus isolates in coculture experiments. Besides, the lactobacilli LRA4, LC2, LR5 and LF9 have counteracted pathogen cytotoxicity. Taken together, the present study revealed some inhibitory activities of lactobacilli against two antibiotic-resistant skin pathogens. Moreover, it revealed two lactobacilli, namely LC2 and LRA4, with antagonistic capacity against different virulence determinants of skin pathogens. These lactobacilli are considered promising probiotic candidates that may represent an alternative therapeutic approach for skin infections.

  17. Multilocus Sequence Typing And Antibiotic Resistance Of Staphylococcus Aureus Isolated From The Brazilian Dairy Industry

    DEFF Research Database (Denmark)

    Dittmann, Karen Kiesbye; Chaul, Luiza; Lee, Sarah

    2015-01-01

    Staphylococcus aureus is a common cause of food poisoning due to enterotoxin production. This is particularly an issue in the dairy industry, where S. aureus can contaminate the product e.g. from raw milk or the handlers. In Brazil, soft cheese is mainly produced in small dairy plants where good...... but the contamination rate varied between the processing plants. Multilocus Sequence Typing was used to type and assess potential persisting sequence types (ST). Seven known STs (ST1, ST5, ST30, ST97, ST126, ST188, ST398) were identified. Three new STs were identified and they all belong to clonal complex (CC) 1, which...

  18. Bactericidal effect of bovine lactoferrin, LFcin, LFampin and LFchimera on antibiotic-resistant Staphylococcus aureus and Escherichia coli

    NARCIS (Netherlands)

    Flores-Villaseñor, H.; Canizalez-Román, A.; Reyes-Lopez, M.; Nazmi, K.; de la Garza, M.; Zazueta-Beltrán, J.; León-Sicairos, N.; Bolscher, J.G.M.

    2010-01-01

    Increased prevalence of antibiotic-resistant bacteria has become a major threat to the health sector worldwide due to their virulence, limited therapeutic options and distribution in both hospital and community settings. Discovery and development of new agents to combat antibiotic-resistant bacteria

  19. Prevalence of antibiotic-resistant S.aureus among general practice patients.

    NARCIS (Netherlands)

    Donker, G.A.; Nys, S.; Driessen, C.; Deurenberg, R.H.; Stobberingh, E.E.

    2006-01-01

    Background: Worldwide, the prevalence of antibiotic-resistant Staphylococcus aureus is an increasing problem both inside and outside the hospital. As antibiotic prescription by general practitioners is mainly an empiric therapy, actual data on antibiotic resistance of the microorganisms involved are

  20. Antibiotic resistance of Staphylococcus aureus isolated from enteral diets in a public hospital of Minas Gerais Resistência a antibióticos de Staphylococcus aureus isolados de dietas enterais em um hospital público de Minas Gerais

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    Nélio José de Andrade

    2007-10-01

    Full Text Available Enteral diets constitute an excellent means for microbial growth due to its composition rich in nutrients and its time of exposure to room temperature during application. Among the pathogenic bacteria there is the Staphylococcus aureus that is an opportunist microorganism found in the humans’ mucous membrane (buccal, nasal and oral. Samples of enteral diet after application as well as of the environment used for the preparation of the diets, were collected in a public hospital in Minas Gerais and analyzed for the presence of S. aureus. The contamination by S. aureus was evidenced in 83% of the enteral diet samples. As for the environment, the values found were in conformity with APHA recommendation. The isolated strains were submitted to the evaluation of the resistance to different antibiotics. Resistance was observed for tetracycline (100%, erythromycin (90,9%, chloramphenicol (59,1%, estreptomycin (22,72%, penicillin 18,8%, vancomycin (13,63%, ampicillin (13,63%, amoxilin (9,09% and gentamicin (4,54%. Due to the versatility in the resistance development to several antibiotics the S. aureus survives in hospital environments and can be diffused among patients. Dietas enterais constituem um excelente meio para crescimento microbiano, devido à sua composição rica em nutrientes e ao tempo de exposição à temperatura ambiente durante a administração. Dentre as bactérias patogênicas que podem ser encontradas nessas dietas, cita-se o Staphylococcus aureus, microrganismo oportunista encontrado na microbiota da membrana mucosa (bucal, nasal e oral em seres humanos. Amostras de dieta enteral pós-administração e do ambiente utilizado para o seu preparo foram coletadas em um hospital público e analisadas quanto à presença de S. aureus. A contaminação foi evidenciada em 83% das amostras de dietas enterais, e, quanto ao ambiente, os valores encontrados se apresentam de acordo com a recomendação da APHA. As cepas isoladas foram

  1. Prevalence of antibiotic resistant Staphylococcus aureus from raw milk samples collected from the local vendors in the region of Tirupathi, India

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    Sudhanthirakodi Sudhanthiramani

    2015-04-01

    Full Text Available Aim: The study was carried out with the aim to identify the suitability of the milk for consumer use with special reference to Staphylococcus aureus from milk samples collected from various local vendors and determine the antibiotic susceptibility pattern of those positive isolates. Materials and Methods: A total of 110 milk samples were collected from the local milk vendors in and around Tirupathi region of India. All the samples were enriched with buffered peptone water in 9:1 ratio and the then inoculated on baird parker agar medium with added 2% egg yolk tellurite emulsion as selective medium for S.aureus and confirmed with mannitol salt agar, Gram’s staining and biochemical tests. The typical cultural characters with coagulase-positive samples were taken as positive samples the positive samples were tested for antibiotic susceptibility with 10 different antibiotics by employing disc diffusion method. Results: Prevalence of coagulase-positive S. aureus was 39.09% (43/110 from the milk samples. The antibiotic susceptibility test of positive isolates showed high resistant toward penicillin G 37/43 (86.04% and ampicillin 32/43 (74.42%, and also showed resistant to methicillin 6/43 (13.95%, cephalothin 6/43 (13.95%, tetracycline 6/43 (13.95%, ciprofloxacin 4/43 (9.30%, enrofloxacin 3/43 (6.97%, cefoxitin 2/43 (4.65%, gentamicin 2/43 (4.65%, and co-trimoxazole 2/43 (4.65%. Many individual isolates showed resistant against two or more antibiotics in our study. Conclusion: The above study results show that the milk samples collected from local vendor having S. aureus, which can induce disease condition as well as antibiotic resistant to the humans particularly young children and old age peoples by means of consumption of raw milk and its products. This is the public health issue, which needs to be solved by educating the local vendors regarding health problems related to unhygienic milk supply and make the awareness among the consumers about this

  2. Mortality and hospital stay associated with resistant Staphylococcus aureus and Escherichia coli bacteremia: estimating the burden of antibiotic resistance in Europe.

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    Marlieke E A de Kraker

    2011-10-01

    Full Text Available BACKGROUND: The relative importance of human diseases is conventionally assessed by cause-specific mortality, morbidity, and economic impact. Current estimates for infections caused by antibiotic-resistant bacteria are not sufficiently supported by quantitative empirical data. This study determined the excess number of deaths, bed-days, and hospital costs associated with blood stream infections (BSIs caused by methicillin-resistant Staphylococcus aureus (MRSA and third-generation cephalosporin-resistant Escherichia coli (G3CREC in 31 countries that participated in the European Antimicrobial Resistance Surveillance System (EARSS. METHODS AND FINDINGS: The number of BSIs caused by MRSA and G3CREC was extrapolated from EARSS prevalence data and national health care statistics. Prospective cohort studies, carried out in hospitals participating in EARSS in 2007, provided the parameters for estimating the excess 30-d mortality and hospital stay associated with BSIs caused by either MRSA or G3CREC. Hospital expenditure was derived from a publicly available cost model. Trends established by EARSS were used to determine the trajectories for MRSA and G3CREC prevalence until 2015. In 2007, 27,711 episodes of MRSA BSIs were associated with 5,503 excess deaths and 255,683 excess hospital days in the participating countries, whereas 15,183 episodes of G3CREC BSIs were associated with 2,712 excess deaths and 120,065 extra hospital days. The total costs attributable to excess hospital stays for MRSA and G3CREC BSIs were 44.0 and 18.1 million Euros (63.1 and 29.7 million international dollars, respectively. Based on prevailing trends, the number of BSIs caused by G3CREC is likely to rapidly increase, outnumbering the number of MRSA BSIs in the near future. CONCLUSIONS: Excess mortality associated with BSIs caused by MRSA and G3CREC is significant, and the prolongation of hospital stay imposes a considerable burden on health care systems. A foreseeable shift in

  3. Antibiotic Resistance Profiling of Staphylococcus aureus Isolated from Clinical Specimens in a Tertiary Hospital from 2010 to 2012

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    Alain C. Juayang

    2014-01-01

    Full Text Available MRSA infection can affect a wide array of individuals that may lead to treatment failure. Also, the infection has the potential to spread from one area to another particularly health care facilities or communities eventually causing minor outbreaks. With this premise, the study aimed to describe MRSA infections using the hospital-based data of a tertiary hospital in Bacolod City, Philippines, from 2010 to 2012. Specifically, this study aimed to evaluate the antimicrobial resistance of S. aureus isolated from clinical specimens and to put emphasis on the prevalence of MRSA and Inducible Clindamycin Resistance. A total of 94 cases from 2010 to 2012 were diagnosed to have S. aureus infection using conventional bacteriologic methods. From these cases, 38 (40.6% were identified as MRSA and 37 (39.4% were inducible clindamycin resistant. Wounds and abscesses were considered to be the most common specimens with MRSA infections having 71.05% while blood was the least with 5.3%. For drug susceptibility, out of the 94 S. aureus cases, including MRSA, 100% were susceptible to linezolid making it the drug of choice for this study. It was then followed by tetracycline having a mean susceptibility of 95%;, while penicillin G was ineffective with 94 cases having 0% susceptibility.

  4. 重症监护室MRSA耐药性及RAPD分析%Antibiotics resistance and RAPD analysis of methicillin - resistant Staphylococcus aureus isolated from ICU

    Institute of Scientific and Technical Information of China (English)

    周秀萍; 杨长顺; 李争鸣; 邱宏

    2012-01-01

    Objective; To investigate the status of antibiotics resistance and the genetic homology of methicillin -resistant staphylococcus aureus in ICU and provide scientific evidence for controlling MRSA infection. Methods; MRSA was identified by mecA PCR. Drug resistance was perfomed using K - B method. The RAPD technique was used to identify the genotypes. Results; The separation rate of MRSA was 58. 5%. MRSA was resistant to many drugs. But all strains were susceptible to vancomycin and teicoplanin. All 24 stains of MRSA produced fingerprints by RAPD, and was classified into four genotypes. 15 strains were II type which was the dominant type. Conclusion; The MRSA isolated from ICU has high and multi drug resistance, we should reasonablly choose drugs according to the susceptibility test. RAPD results reveal the special epidemic genotypes of MRSA and this study can provide molecular epidemiological evidence for control of MRSA infection.%目的:调查重症监护室耐甲氧西林金黄色葡萄球菌的耐药及分子流行病学情况,为控制感染提供科学依据.方法:ICU分离的金黄色葡萄球菌采用mecA基因检测法确定MRSA,对筛选出的MRSA采用纸片法检测其耐药性,用随机扩增多态性DNA( RAPD)进行分子流行病学分析.结果:MRSA的分离率为58.5%,对多种抗生素均耐药,没有发现耐万古霉素和替考拉宁的菌株.24株MRSA经RAPD分型,均获得稳定的条带,可分为四型,以Ⅱ型为主,共检出15株.结论:ICU分离MRSA菌株具有多重耐药性,应根据药敏试验结果合理选用抗生素进行治疗;通过RAPD分型研究,可了解MRSA的基因型流行特征,为控制感染提供分子流行病学依据.

  5. Identification of gene clusters associated with host adaptation and antibiotic resistance in Chinese Staphylococcus aureus isolates by microarray-based comparative genomics.

    Directory of Open Access Journals (Sweden)

    Henan Li

    Full Text Available A comparative genomic microarray comprising 2,457 genes from two whole genomes of S. aureus was employed for the comparative genome hybridization analysis of 50 strains of divergent clonal lineages, including methicillin-resistant S. aureus (MRSA, methicillin-susceptible S. aureus (MSSA, and swine strains in China. Large-scale validation was confirmed via polymerase chain reaction in 160 representative clinical strains. All of the 50 strains were clustered into seven different complexes by phylogenetic tree analysis. Thirteen gene clusters were specific to different S. aureus clones. Ten gene clusters, including seven known (vSa3, vSa4, vSaα, vSaβ, Tn5801, and phage ϕSa3 and three novel (C8, C9, and C10 gene clusters, were specific to human MRSA. Notably, two global regulators, sarH2 and sarH3, at cluster C9 were specific to human MRSA, and plasmid pUB110 at cluster C10 was specific to swine MRSA. Three clusters known to be part of SCCmec, vSa4 or Tn5801, and vSaα as well as one novel gene cluster C12 with homology with Tn554 of S. epidermidis were identified as MRSA-specific gene clusters. The replacement of ST239-spa t037 with ST239-spa t030 in Beijing may be a result of its acquisition of vSa4, phage ϕSa1, and ϕSa3. In summary, thirteen critical gene clusters were identified to be contributors to the evolution of host specificity and antibiotic resistance in Chinese S. aureus.

  6. Simultaneous breakdown of multiple antibiotic resistance mechanisms in S. aureus.

    Science.gov (United States)

    Kaneti, Galoz; Sarig, Hadar; Marjieh, Ibrahim; Fadia, Zaknoon; Mor, Amram

    2013-12-01

    In previous studies, the oligo-acyl-lysyl (OAK) C12(ω7)K-β12 added to cultures of gram-positive bacteria exerted a bacteriostatic activity that was associated with membrane depolarization, even at high concentrations. Here, we report that multidrug-resistant Staphylococcus aureus strains, unlike other gram-positive species, have reverted to the sensitive phenotype when exposed to subminimal inhibitory concentrations (sub-MICs) of the OAK, thereby increasing antibiotics potency by up to 3 orders of magnitude. Such chemosensitization was achieved using either cytoplasm or cell-wall targeting antibiotics. Moreover, eventual emergence of resistance to antibiotics was significantly delayed. Using the mouse peritonitis-sepsis model, we show that on single-dose administration of oxacillin and OAK combinations, death induced by a lethal staphylococcal infection was prevented in a synergistic manner, thereby supporting the likelihood for synergism to persist under in vivo conditions. Toward illuminating the molecular basis for these observations, we present data arguing that sub-MIC OAK interactions with the plasma membrane can inhibit proton-dependent signal transduction responsible for expression and export of resistance factors, as demonstrated for β-lactamase and PBP2a. Collectively, the data reveal a potentially useful approach for overcoming antibiotic resistance and for preventing resistance from emerging as readily as when bacteria are exposed to an antibiotic alone.

  7. Mortality and Hospital Stay Associated with Resistant Staphylococcus aureus and Escherichia coli Bacteremia : Estimating the Burden of Antibiotic Resistance in Europe

    NARCIS (Netherlands)

    de Kraker, Marlieke E. A.; Davey, Peter G.; Grundmann, Hajo

    2011-01-01

    Background: The relative importance of human diseases is conventionally assessed by cause-specific mortality, morbidity, and economic impact. Current estimates for infections caused by antibiotic-resistant bacteria are not sufficiently supported by quantitative empirical data. This study determined

  8. Insertion sequence IS256 in canine pyoderma isolates of Staphylococcus pseudintermedius associated with antibiotic resistance.

    Science.gov (United States)

    Casagrande Proietti, P; Bietta, A; Coletti, M; Marenzoni, M L; Scorza, A V; Passamonti, F

    2012-06-15

    Staphylococcus pseudintermedius is the most frequent staphylococcal species isolated from canine pyoderma. The control of S. pseudintermedius infection is often difficult due to the expanded antimicrobial resistance phenotypes. Antibiotic resistance in staphylococcal pathogens is often associated to mobile genetic elements such as the insertion sequence IS256 that was first described as a part of the transposon Tn4001, which confers aminoglycoside resistance in Staphylococcus aureus and in Staphylococcus epidermidis. In this study a collection of 70 S. pseudintermedius isolates from canine pyoderma was used to investigate antimicrobial susceptibility to 15 antibiotics and the presence of IS256, not revealed in S. pseudintermedius yet. Antibiotic resistance profiling demonstrated that all S. pseudintermedius isolates had a multi-drug resistance phenotype, exhibiting simultaneous resistance to at least five antibiotics; indeed methicillin resistant S. pseudintermedius isolates were simultaneously resistant to at least nine antibiotics and all were also gentamicin resistant. PCR analyses revealed the presence of IS256 in 43/70 S. pseudintemedius isolates. The association between the presence of IS256 and the resistance was particularly significant for certain antibiotics: cefovecin, amikacin, gentamicin and oxacillin (χ(2)p-valuepseudintermedius isolates and its association with antibiotic resistance. Our findings suggest that S. pseudintermedius may acquire antibiotic resistance genes through mobile genetic elements which may play a predominant role in the dissemination of multi-drug resistance.

  9. Nanoparticles functionalized with ampicillin destroy multiple-antibiotic-resistant isolates of Pseudomonas aeruginosa and Enterobacter aerogenes and methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Brown, Ashley N; Smith, Kathryn; Samuels, Tova A; Lu, Jiangrui; Obare, Sherine O; Scott, Maria E

    2012-04-01

    We show here that silver nanoparticles (AgNP) were intrinsically antibacterial, whereas gold nanoparticles (AuNP) were antimicrobial only when ampicillin was bound to their surfaces. Both AuNP and AgNP functionalized with ampicillin were effective broad-spectrum bactericides against Gram-negative and Gram-positive bacteria. Most importantly, when AuNP and AgNP were functionalized with ampicillin they became potent bactericidal agents with unique properties that subverted antibiotic resistance mechanisms of multiple-drug-resistant bacteria.

  10. Sensitivity of antibiotic resistant and antibiotic susceptible Escherichia coli, Enterococcus and Staphylococcus strains against ozone.

    Science.gov (United States)

    Heß, Stefanie; Gallert, Claudia

    2015-12-01

    Tolerance of antibiotic susceptible and antibiotic resistant Escherichia coli, Enterococcus and Staphylococcus strains from clinical and wastewater samples against ozone was tested to investigate if ozone, a strong oxidant applied for advanced wastewater treatment, will affect the release of antibiotic resistant bacteria into the aquatic environment. For this purpose, the resistance pattern against antibiotics of the mentioned isolates and their survival after exposure to 4 mg/L ozone was determined. Antibiotic resistance (AR) of the isolates was not correlating with higher tolerance against ozone. Except for ampicillin resistant E. coli strains, which showed a trend towards increased resistance, E. coli strains that were also resistant against cotrimoxazol, ciprofloxacin or a combination of the three antibiotics were similarly or less resistant against ozone than antibiotic sensitive strains. Pigment-producing Enterococcus casseliflavus and Staphylococcus aureus seemed to be more resistant against ozone than non-pigmented species of these genera. Furthermore, aggregation or biofilm formation apparently protected bacteria in subsurface layers from inactivation by ozone. The relatively large variance of tolerance against ozone may indicate that resistance to ozone inactivation most probably depends on several factors, where AR, if at all, does not play a major role.

  11. Staphylococcus aureus and Pregnancy

    Science.gov (United States)

    Staphylococcus aureus and Pregnancy In every pregnancy, a woman starts out with a 3-5% chance of having a ... This sheet talks about whether exposure to staphylococcus aureus may increase the risk for birth defects over ...

  12. Analysis of antibiotic-resistant gene mecA and pathogenic genes in Staphylococcus aureus%金黄色葡萄球菌耐药基因及致病毒素基因的研究

    Institute of Scientific and Technical Information of China (English)

    王凤玲; 刘静; 杨青

    2009-01-01

    目的 研究金葡菌耐药基因及致病因子中毒休克综合征毒素-Ⅰ(TSST-Ⅰ)基因和杀白细胞毒素 (PVL) 基因的分布特征.方法 收集临床分离的74株金葡菌,PCR法检测毒素基因TSST-Ⅰ、PVL和mecA耐药基因.结果 74株金葡菌 PCR法对其行mecA基因检测,检出率为55.4% (41/74).PVL阳性菌株的分离率为29.7%(22/74),PVL阳性的MRSA为15株(15/41,36.6%), PVL阳性的MSSA为7株(7/33,21.2%),差异无统计学意义(P>0.05).TSST-Ⅰ基因检出率为6.8%, MSSA中未检出TSST-Ⅰ基因.结论 MRSA呈多重耐药性,易造成医院内暴发流行,携带PVL和TSST-Ⅰ的金葡菌其致病力更强,应加强医院感染控制,防止其播散流行.%Objective To investigate the antibiotic-resistant gene mecA and the prevalence of Panton-Valentine leukocidin (PVL) gene, toxic shock syndrome toxin (TSST-Ⅰ) gene in S. aureus. Methods A total of 74 S. aureus were collected from clinical specimens. The mecA, PVL and TSST-Ⅰ genes were detected by PCR.Results PVL gene was identified in 22 S. aureus isolates. The prevalence of PVL was 29.7% in S. aureus, 36.6% in MRSA and 21.2% in MSSA. The difference was not statistically significant (P>0.05). The prevalence of MRSA was 55.4% in 74 S. aureus. The prevalence of TSST-Ⅰ gene was 6.8%. TSST-Ⅰ gene was not detected in MSSA.Conclusions MRSA strains show highly resistant to antibiotics. PVL- and TSST-Ⅰ-positive S. aureus are more pathogenic.

  13. Effect of Shuanghuanglian Combined with Levofloxacin on Antibiotic Resistance of Staphylococcus Aureus ATCC29213 in Rabbit Tissue Cage Infection Model%双黄连联用左氧氟沙星对兔组织笼感染模型中金黄色葡萄球菌ATCC29213耐药性的影响

    Institute of Scientific and Technical Information of China (English)

    王国俊; 叶云; 冯碧敏; 李虹

    2014-01-01

    Objective To explore effects of shuanghuanglian combined with levofloxacin on antibiotic resistance of Staphylococcus Aureus ATCC29213 to levofloxacin. Methods Tissue cage infection model with Staphylococcus aureus was established in rabbits, and the infected animals were given with levofloxacin alone ( group A ) or in combination with shuanghuanglian ( group B) for 5 days respectively. Steady-state concentration of levofloxacin in tissue cage, bacteria recovery and bacterial resistance in tissue cage infection model were studied. Results Steady-state concentration of levofloxacin in tissue cage was not significantly different between group A and group B. The recovery rate of bacteria was significantly lower in group B than in group A (20. 0% vs. 100. 0%). The minimum inhibitory concentration (MIC) was lower in group B than in group A. Conclusion Shuanghuanglian combined with levofloxacin is helpful to reduce antibiotic resistance of Staphylococcus aureus to levofloxacin, indicating that some Chinese traditional medicine combined with antibiotics can reduce antibiotic resistance.%目的探讨双黄连联合左氧氟沙星对兔组织笼感染模型中金黄色葡萄球菌ATCC29213对左氧氟沙星的耐药性的影响。方法建立兔组织笼感染模型,分别用左氧氟沙星单独处理(A组)及双黄连联合左氧氟沙星处理(B组)5 d,探讨兔组织笼感染模型中左氧氟沙星在组织液中稳态浓度及经处理后兔组织笼中细菌恢复生长的情况和细菌耐药性变化。结果两组左氧氟沙星在组织液中浓度差异无统计学意义。 B组兔组织笼内细菌恢复生长发生率(20%)明显低于A组(100.0%),而左氧氟沙星对B组兔组织笼内细菌的最低抑菌浓度(MIC)值明显低于A组。结论双黄连与左氧氟沙星联合治疗有助于减少金黄色葡萄球菌对左氧氟沙星的耐药现象,提示中药联合抗菌药物可降低细菌对抗菌药物的耐药性。

  14. Epidemiology and antibiotic resistance of methicillin-resistant Staphylococcus aureus in Jingzhou%荆州地区耐甲氧西林金黄色葡萄球菌的流行和耐药特征分析

    Institute of Scientific and Technical Information of China (English)

    周义正; 李艳; 王昌富

    2014-01-01

    目的 调查荆州地区社区相关性和医院相关性耐甲氧西林金黄色葡萄球菌(CA-MRSA和HA-MRSA)的流行和耐药特征.方法 连续收集2012年1月至2013年12月分离自荆州市中心医院门诊和住院患者送检样本的MRSA 159株.检测16种抗菌药物对所有菌株的最小抑菌浓度,采用多重PCR检测所有菌株的SCCmec分子型别,并分别以脉冲场凝胶电泳(PFGE)和耐药谱聚类分析对ICU的MRSA进行同源性分析.采用WHONET 5.6和SPSS 19.0软件对相关数据进行统计分析.结果 159株MRSA中,HA-MRSA 131株(82.4%),CA-MRSA 28株(17.6%).HA-MRSA和CA-MRSA在患者年龄、病区分布、来源样本类型、住院时间、抗感染治疗时间、感染类型和基础疾病的构成上差异有统计学意义(x2=19.103,31.372,59.756,71.703,54.153,59.756和54.232,P<0.01).159株MRSA中未检出对万古霉素、利奈唑胺、替加环素和呋喃妥因耐药的菌株,但所有菌株对青霉素、头孢西丁和苯唑两林均耐药.HA-MRSA对莫西沙星、利福平、左氧氟沙星、环丙沙星和庆大霉素的耐药性高于CA-MRSA(x2=30.179,27.352,28.523,28.523和25.987,P<0.01),但对红霉素和克林霉素的耐药性低于CA-MRSA(x2=13.106和11.743,P<0.01).159株MRSA中,SCCmecⅡ型12株(7.5%),Ⅲ型113株(71.1%),Ⅳ型26株(16.4%),未能分型8株,CA-MRSA和HA-MRSA分别以Ⅳ(26/28,92.9%)型和Ⅲ型(113/131,86.3%)为主.ICU病区分离的49株HA-MRSA,经PFGE分型可分为6型,以Al(24株,49.0%)、A2亚型(9株,18.4%)和B型(9株,18.4%)为主;耐药谱聚类分析发现3群相关性很高的HA-MRSA,其对应的PFGE型别显示其分属于A1、A2亚型和B型.结论 荆州地区流行的MRSA以HA-MRSA为主,其与CA-MRSA在患者年龄、病区分布、感染类型以及耐药性等方面均显示出差异.HA-MRSA以SCCmecⅢ型为主,且在ICU病区存在HA-MRSA暴发流行.%Objective To investigate the epidemiology and antibiotic resistance of communityassociated

  15. Controlling antibiotic resistance in the ICU

    NARCIS (Netherlands)

    Derde, L.P.G.

    2013-01-01

    Patients admitted to intensive care units (ICUs) are frequently colonized with (antibiotic-resistant) bacteria, which may lead to healthcare associated infections. Antimicrobial-resistant bacteria (AMRB), such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (V

  16. Antibiotic resistance of Streptococcus pneumoniae and Staphylococcus aureus isolates from children's throat swab and sputum%儿童呼吸道肺炎链球菌和金黄色萄萄球菌的耐药性研究

    Institute of Scientific and Technical Information of China (English)

    邱素清; 向华国; 莆荣

    2011-01-01

    目的 了解儿童感染肺炎链球菌和金黄色萄萄球菌耐药情况,为临床合理用药提供理论依据.方法 对年龄为1个月~12岁的上呼吸道感染的儿童鼻咽分泌物或痰进行培养,分离肺炎链球菌和金黄色萄萄球菌;采用纸片扩散法及E-test法对分离株进行常用的10种抗生素敏感性检测.结果 从2250例呼吸道感染儿童鼻咽部、痰液分离出肺炎链球菌共120株,金黄色葡萄球菌共151株.120株肺炎链球菌对常用抗菌药物耐药率分别为青霉素41.7% (50/120)、苯唑西林26.7%(32/120)、头孢曲松9.2%(11/120)、红霉素95.8%(115/120)、克林霉素90.0% (108/120)、四环素70.8% (85/120)、氯霉素6.7%(8/120)、利福平0.8%(1/120)和氧氟沙星0.8%(1/120),肺炎链球菌青霉素不敏感株对β-内酰胺酶类耐药率明显高于青霉素敏感株.151株金黄色葡萄球菌中对常用抗菌药物耐药率分别为青霉素97.4%(147/151)、苯唑西林9.9%(15/151)、头孢曲松9.3%( 14/151),对红霉素52.3%(79/151)、四环素31.8% (48/151)、克林霉素24.5%(37/151)、氯霉素9.9%( 15/151)、氧氟沙星3.3% (5/151)和利福平2.0%(3/151).未检出耐万古霉素菌株.结论 肺炎链球菌对红霉素、克林霉素高度耐药;而金黄色葡萄球菌对青霉素高度耐药,临床应尽量减少此类药物的经验性用药,依据药敏结果选择抗菌药物进行治疗.%Objective To investigate the drug resistance of Streptococcus pneumoniae (SP) and Staphylococcus aureus isolated from children in order to provide clinical guidelines for the rational using of antimicrobial drugs. Method The Sp and Staphylococcus aureus were cultured, isolated and identified from throat swabs or sputum specimens of children aging 1 month to 12 years with respiratory infection. Kirby-Bauer disc diffusion and E-test for antibiotic susceptibility were performed for these clinical isolates. Result Totally 120 and 151 strains of SP

  17. Retail ready-to-eat food as a potential vehicle for Staphylococcus spp. harboring antibiotic resistance genes.

    Science.gov (United States)

    Chajęcka-Wierzchowska, Wioleta; Zadernowska, Anna; Nalepa, Beata; Sierpińska, Magda; Laniewska-Trokenheim, Lucja

    2014-06-01

    Ready-to-eat (RTE) food, which does not need thermal processing before consumption, could be a vehicle for the spread of antibiotic-resistant microorganisms. As part of general microbiological safety checks, staphylococci are routinely enumerated in these kinds of foods. However, the presence of antibiotic-resistant staphylococci in RTE food is not routinely investigated, and data are only available from a small number of studies. The present study evaluated the pheno- and genotypical antimicrobial resistance profile of Staphylococcus spp. isolated from 858 RTE foods (cheeses, cured meats, sausages, smoked fishes, salads). Of 113 strains isolated, S. aureus was the most prevalent species, followed by S. xylosus, S. saprophyticus, and S. epidermidis. More than half (54.9%) of the isolates were resistant to at least one class of tested antibiotic; of these, 35.4% of the strains were classified as multidrug resistant. Most of the isolates were resistant to cefoxitin (49.6%), followed by clindamycin (39.3%), tigecycline (27.4%), quinupristin-dalfopristin (22.2%), rifampin (20.5%), tetracycline (17.9%), and erythromycin (8.5%). All methicillin-resistant staphylococci harbored the mecA gene. Among the isolates resistant to at least one antibiotic, 38 harbored tetracycline resistance determinant tet (M), 24 harbored tet (L), and 9 harbored tet (K). Of the isolates positive for tet (M) genes, 34.2% were positive for the Tn916-Tn1545-like integrase family gene. Our results indicated that retail RTE food could be considered an important route for the transmission of antibiotic-resistant bacteria harboring multiple antibiotic resistance genes.

  18. Isolation,Indentification and Antibiotic Resistance Analysis of Methicillin-resistant Staphylococcus aureus (MRSA)from Raw Cow Milk%奶牛源MRSA菌株的分离鉴定和耐药性分析

    Institute of Scientific and Technical Information of China (English)

    冯清; 秦爱建; 金文杰; 林伟东; 张大帅; 戴迪; 廖俊; 王仙; 汪怿旸; 梁祥焕; 张军

    2016-01-01

    本研究对部分奶牛场采集的502份隐性乳房炎试验(california mastitis test,CMT)检测呈阳性的奶样进行细菌分离、鉴定,运用多重 PCR 方法筛选出耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus au-reus ,MRSA),并对分离出的MRSA用纸片扩散法进行药敏试验,检测其对19种抗菌药物的敏感性。结果显示,分离到细菌的奶样有452份,其中检出葡萄球菌338株,MRSA 89株;MRSA 分离株主要对万古霉素、磷霉素、氯霉素和克拉霉素敏感,对青霉素、多黏菌素、大观霉素及头孢他啶具有较强的耐药性。本研究为指导奶牛乳房炎用药、MRSA菌株的快速鉴定及制定 MRSA感染的防控措施提供参考。%In this study,we collected 502 california mastitis test (CMT)positive milk samples from several cattle farms and then the bacteria were isolated and identified from them.After that, we used multiplex-PCR for screening out methicillin-resistant Staphylococcus aureus (MRSA). Then we investigated the MRSA’s antibiotics susceptibility to 1 9 kinds of antibiotics by discdiffu-sion method.The results showed that 338 strains of Staphylococci including 89 strains of MRSA were detected out from the 452 milk samples with bacteria.Additionally,most MRSA showed high sensitivity to vancomycin,fosfomycin,chloramphenicol and clarithromycin,while resistant to penicillin,polymyxin,spectinomycin and ceftazidime.The results provided certain factual basis and method for guiding the use of antibiotics in bovine mastitis,rapid identification of MRSA strains and prevention or control of MRSA infection.

  19. Antibiotic resistance and molecular characterization of ophthalmic Staphylococcus pseudintermedius isolates from dogs.

    Science.gov (United States)

    Kang, Min-Hee; Chae, Min-Joo; Yoon, Jang-Won; Kim, Seung-Gon; Lee, So-Young; Yoo, Jong-Hyun; Park, Hee-Myung

    2014-01-01

    The prevalence, virulence potential, and antibiotic resistance of ophthalmic Staphylococcus pseudintermedius (SP) isolated from dogs were examined. Sixty-seven Staphylococcus species were isolated from ophthalmic samples and surveyed for species-specific sequences in the Staphylococcus intermedius group (SIG) nuclease gene (SInuc), exfoliative toxin gene for SIG (siet), and antibiotic resistance genes (blaZ and mecA). PCR-restriction fragment length polymorphism analysis of the pta gene was also performed. Fifty isolates were identified as SIG strains, all of which were found to be SP. The blaZ gene was detected in 42 of the 50 SP strains and mecA gene was observed in 18 of the 50 SP strains. The 50 SP strains were most susceptible to amoxicillin/clavulanic acid (94%) and chlorampenicol (70%), and highly resistant to tetracycline (94%) and penicillin (92%). It was also found that 16 (88.9%) mecA-positive SP strains were resistant to oxacillin, tetracycline and penicillin. All mecA-positive SP were resistant to more than four of the eight tested antibiotics and therefore considered SP with multi-drug resistance (MDR). Our results indicate a high prevalence of antibiotic resistance genes in ophthalmic SP along with a close relationship between MDR SP strains and the mecA gene. Based on our findings, judicious administration of antibiotics to companion dogs is necessary.

  20. Staphylococcus aureus toxins.

    Science.gov (United States)

    Otto, Michael

    2014-02-01

    Staphylococcus aureus is a dangerous pathogen that causes a variety of severe diseases. The virulence of S. aureus is defined by a large repertoire of virulence factors, among which secreted toxins play a preeminent role. Many S. aureus toxins damage biological membranes, leading to cell death. In particular, S. aureus produces potent hemolysins and leukotoxins. Among the latter, some were recently identified to lyse neutrophils after ingestion, representing an especially powerful weapon against bacterial elimination by innate host defense. Furthermore, S. aureus secretes many factors that inhibit the complement cascade or prevent recognition by host defenses. Several further toxins add to this multi-faceted program of S. aureus to evade elimination in the host. This review will give an overview over S. aureus toxins focusing on recent advances in our understanding of how leukotoxins work in receptor-mediated or receptor-independent fashions.

  1. Phenotypic and genotypic antimicrobial resistance traits of foodborne Staphylococcus aureus isolates from Shanghai

    Science.gov (United States)

    Staphylococcus aureus is a recognized pathogen in humans, which causes nosocomial infections and food poisoning. The transmission of antibiotic resistant S. aureus (ARSA), especially methicillin-resistant S. aureus (MRSA), between food products and humans has become a serious problem. Hence, it is n...

  2. Phenotype Switching Is a Natural Consequence of Staphylococcus aureus Replication

    OpenAIRE

    Edwards, Andrew M.

    2012-01-01

    The pathogen Staphylococcus aureus undergoes phenotype switching in vivo from its normal colony phenotype (NCP) to a slow-growing, antibiotic-resistant small-colony-variant (SCV) phenotype that is associated with persistence in host cells and tissues. However, it is not clear whether phenotype switching is the result of a constitutive process that is selected for under certain conditions or is triggered by particular environmental stimuli. Examination of cultures of diverse S. aureus strains ...

  3. Prevalence of the Antibiotic Resistance Genes in Coagulase-Positive-and Negative-Staphylococcus in Chicken Meat Retailed to Consumers

    Science.gov (United States)

    Osman, Kamelia; Badr, Jihan; Al-Maary, Khalid S.; Moussa, Ihab M. I.; Hessain, Ashgan M.; Girah, Zeinab M. S. Amin; Abo-shama, Usama H.; Orabi, Ahmed; Saad, Aalaa

    2016-01-01

    The use of antibiotics in farm management (growing crops and raising animals) has become a major area of concern. Its implications is the consequent emergence of antibiotic resistant bacteria (ARB) and accordingly their access into the human food chain with passage of antibiotic resistance genes (ARG) to the normal human intestinal microbiota and hence to other pathogenic bacteria causative human disease. Therefore, we pursued in this study to unravel the frequency and the quinolone resistance determining region, mecA and cfr genes of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), methicillin-resistant coagulase-negative staphylococci (MRCNS) and methicillin-susceptible coagulase-negative staphylococci (MSCNS) isolated from the retail trade of ready-to-eat raw chicken meat samples collected during 1 year and sold across the Great Cairo area. The 50 Staphylococcus isolated from retail raw chicken meat were analyzed for their antibiotic resistance phenotypic profile on 12 antibiotics (penicillin, oxacillin, methicillin, ampicillin-sulbactam, erythromycin, tetracycline, clindamycin, gentamicin, ciprofloxacin, chloramphenicol, sulfamethoxazole-trimethoprim, and vancomycin) and their endorsement of the quinolone resistance determining region, mecA and cfr genes. The isolation results revealed 50 isolates, CPS (14) and CNS (36), representing ten species (S. aureus, S. hyicus, S. epidermedius, S. lugdunensis, S. haemolyticus, S. hominus, S. schleiferi, S. cohnii, S. intermedius, and S. lentus). Twenty seven isolates were methicillin-resistant. Out of the characterized 50 staphylococcal isolates, three were MRSA but only 2/3 carried the mecA gene. The ARG that bestows resistance to quinolones, β-lactams, macrolides, lincosamides, and streptogramin B [MLS(B)] in MRSA and MR-CNS were perceived. According to the available literature, the present investigation was a unique endeavor into the identification of the quinolone

  4. Prevalence of the antibiotic resistance genes in coagulase-positive- and negative-Staphylococcus in chicken meat retailed to consumers

    Directory of Open Access Journals (Sweden)

    Kamelia Mahmoud Osman

    2016-11-01

    Full Text Available The use of antibiotics in farm management (growing crops and raising animals has become a major area of concern. Its implications is the consequent emergence of antibiotic resistant bacteria (ARB and accordingly their access into the human food chain with passage of antibiotic resistance genes (ARG to the normal human intestinal microbiota and hence to other pathogenic bacteria causative human disease. Therefore, we pursued in this study to unravel the frequency and the quinolone resistance determining region, mecA and cfr genes of methicillin-susceptible Staphylococcus aureus (MSSA, methicillin-resistant S. aureus (MRSA, methicillin-resistant coagulase-negative staphylococci (MRCNS and methicillin-susceptible coagulase-negative staphylococci (MSCNS isolated from the retail trade of ready-to-eat raw chicken meat samples collected during one year and sold across the Great Cairo area. The 50 Staphylococcus isolated from retail raw chicken meat were analyzed for their antibiotic resistance phenotypic profile on 12 antibiotics (penicillin, oxacillin, methicillin, ampicillin-sulbactam, erythromycin, tetracycline, clindamycin, gentamicin, ciprofloxacin, chloramphenicol, sulfamethoxazole-trimethoprim and vancomycin and their endorsement of the quinolone resistance determining region, mecA and cfr genes. The isolation results revealed 50 isolates, CPS (14 and CNS (36, representing ten species (S. aureus, S. hyicus, S. epidermedius, S. lugdunensis, S. haemolyticus, S. hominus, S. schleiferi, S. cohnii, S. intermedius and S. lentus. Twenty seven isolates were methicillin-resistant. Out of the characterized 50 staphylococcal isolates, three were MRSA but only 2/3 carried the mecA gene. The ARG that bestows resistance to quinolones, β-lactams, macrolides, lincosamides and streptogramin B (MLS(B in MRSA and MR-CNS were perceived. According to the available literature, the present investigation was a unique endeavor into the identification of the quinolone

  5. Eugenol Provokes ROS-Mediated Membrane Damage-Associated Antibacterial Activity Against Clinically Isolated Multidrug-Resistant Staphylococcus aureus Strains

    OpenAIRE

    2016-01-01

    Due to the indiscriminate use of antibiotics, resistance to antibiotics has increased remarkably in Staphylococcus aureus. Vancomycin is the final drug to treat the S. aureus infection, but nowadays, resistance to this antibiotic is also increasing. So, the investigation of antibiotic resistance pattern is important. As there is already resistance to vancomycin, there is an urgent need to develop a new kind of antimicrobial to treat S. aureus infection. Eugenol may be the new drug of choice. ...

  6. 耐甲氧西林金黄色葡萄球菌耐药表型分型与耐药基因检测分析研究%Antibiotic resistance phenotype and gene detection of methicillin-resistant staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    郭云龙; 赵先进; 韩宏艳; 孙静; 张丽珍; 戎建荣

    2012-01-01

    Objective To identify the phenotypes and genes of antibiotic resistance in methicillin-resistant staphylococcus aureus (MRSA), and to explore the effective approach for control of MRSA infection. Methods Van-comycin, linezolid and oxacillin resistance tests and gene detections were performed on the clinically isolated MRSA strains using trace broth diluting technique and multiple polymerase chain reaction that were in line with standardized operating procedures established by American Clinical Laboratory Standardization Institute (CLSI). Results MRSA strains were divided into phenotypes I ~\\1, which had developed multiple antibiotic resistance. The resistance rate of vancomycin, linezolid, chloramphenicol, compound trimethoprim-sulfamethoxazole, rifampicin and β-lactams was 0, 7.0%, 40.8%, 47.9%, 60.6% and 100%, respectively. Detectable rate of strains containing resistance genes of mecA, mecA、ermA、ermC、tetK、tetM、ratA was 98.6%>60.6%>18.3%>100%>7.0% and 0, respectively. Conclusion MRSA strains were sensitive to vancomycin and linezolid but resistant to multiple antibiotics. Clinical reports concerning intensive monitoring on minimal inhibitory concentration of antibiotics including vancomycin, linezolid, chloramphenicol, compound trimethoprim-sulfamethoxazole and rifampicin needs to be directed. Attention should also be attached to those with poor response to vancomycin.%目的 分析研究耐甲氧西林金黄色葡萄球菌(methicillin-resistant staphylococcus aureus,MRSA)的耐药表型及耐药基因,探索治疗MRSA感染的有效手段.方法 对临床分离的耐甲氧西林金黄色葡萄球菌株,依据美国临床实验室标准化研究所(CLSI)标准操作规程进行万古霉素、利奈唑胺和苯唑西林等药物的药物敏感性试验和耐药基因检测,分别采用微量肉汤稀释法和多重聚合酶链反应(PCR)扩增法.结果 MRSA耐药表型分为Ⅰ~Ⅶ型,MRSA对抗生素产生多重耐药,万古霉素、利奈唑胺、

  7. Antibiotic resistance and enterotoxin genes in Staphylococcus sp. isolates from polluted water in Southern Brazil

    Directory of Open Access Journals (Sweden)

    ANA P. BASSO

    2014-12-01

    Full Text Available The aim of this study was to evaluate the species distribution, antibiotic-resistance profile and presence of enterotoxin (SE genes in staphylococci isolated from the Dilúvio stream in South Brazil. Eighty-eight staphylococci were identified, 93.18% were identified as coagulase-negative (CNS and 6.82% coagulase-positive (CPS. Fourteen Staphylococcus species were detected and the most frequently were Staphylococcus cohnii (30.48% and S. haemolyticus (21.95%. Resistance to erythromycin was verified in 37.50% of the strains, followed by 27.27% to penicillin, 12.50% to clindamycin, 6.81% to trimethoprim-sulfamethoxazole, 5.68% to chloramphenicol and 2.27% to norfloxacin. None of the investigated strains showed gentamicin and ciprofloxacin resistance. The strains were tested for the presence of sea, seb, sec, sed and see genes by PCR and only CNS strains (43.18% showed positive results to one or more SE genes. The scientific importance of our results is due to the lack of data about these topics in polluted waters in Brazil. In conclusion, polluted waters from the Dilúvio stream may constitute a reservoir for disseminating antibiotic-resistance and enterotoxin into the community. In addition, the detection of staphylococci in the polluted waters of the Dilúvio stream indicated a situation of environmental contamination and poor sanitation conditions.

  8. Staphylococcus aureus: resistance pattern and risk factors

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    Mohammad Naghavi-Behzad

    2015-03-01

    Full Text Available Introduction: Methicillin resistant Staphylococcus aureus (MRSA has emerged as a nosocomial pathogen of major worldwide importance and is an increasingly frequent cause of community-acquired infections. In this study, different risk factors and MRSA resistance pattern were investigated. Methods: In a 24 months period, all of the patients who were confined to bed in the surgery ward were included in the study. Then they were assessed to find out as if they had MRSA infection when hospitalized and once when they were discharged. Almost 48 h after admission, when patients were discharged, social and medical histories were acquired. Acquired samples were examined. Results: During the present study of 475 patients, 108 patients (22.8% had S. aureus. About frequency of antibiotic resistance among collected S. aureus colonies, erythromycin resistance, was the most frequent antibiotic resistance, also resistance to vancomycin was 0.4% that was the least. Only hospitalization duration had statistically significant correlation with antibiotic resistance, also resistance to erythromycin had statistically significant relation with history of surgery and alcohol consumption. Of all 34 MRSA species, 22 (64.7% samples were resistant to erythromycin, 17 (50.0% resistant to cefoxitin, 5 (14.7% resistant to mupirocin, 1 (2.9% resistant to vancomycin and 1 (2.9% resistant to linezolid. Conclusion: The results of the current study show that among hospitalized patients, there is resistance against methicillin. Since based on results of the study there is resistance against oxacillin and erythromycin in most cases, administering appropriate antibiotics have an important role in minimizing the resistance burden among bacterial species.

  9. Norlichexanthone Reduces Virulence Gene Expression and Biofilm Formation in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Baldry, Mara; Nielsen, Anita; Bojer, Martin S.;

    2016-01-01

    Staphylococcus aureus is a serious human pathogen and antibiotic resistant, community-associated strains, such as the methicillin resistant S. aureus (MRSA) strain USA300, continue to spread. To avoid resistance, anti-virulence therapy has been proposed where toxicity is targeted rather than viab...

  10. The Effect of Essential Oils on Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Seda Ozdikmenli

    2014-05-01

    Full Text Available Diseases caused by Staphylococcus aureus are widespread through the world in spite of developing technology. S. aureus is an important pathogen causing food intoxications besides hospital infections by its antibiotic resistant strains. Nowadays, there has been worldwide increasing concern on usage of natural products to control microorganisms. One of these natural products is essential oils. They are produced from plants especially from spices and composed of many components and volatiles. This review summarizes informative literature on essential oils and their mode of antimicrobial action. In addition, current knowledge on in vitro researches on antibacterial activity of essential oils and food applications to control S. aureus has been discussed.

  11. Linezolid resistant Staphylococcus aureus

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    Pavani Gandham

    2014-08-01

    Full Text Available Linezolid is the only antibiotic available as an oral formulation for resistant staphylococcal infections. It is effective in skin and soft tissue infections, nosocomial pneumonias including VAP, infective endocarditis and MRSA meningitis. It is also effective in the eradication of both nasal and throat colonization of MRSA. Its high bioavailability and post antibiotic effect, ease of switching to oral therapy during its use and the fact that it can be used in patients of all ages, also in patients with liver disease and poor kidney function and its increased effectiveness over glycopeptides makes this drug a precious drug in the treatment of resistant staphylococcal infections. Linezolid resistance in staphylococcus is defined as a linezolid MIC of and #8805;8 mg/L. Reported Linezolid resistance in India and elsewhere is 2-20%. There is clonal dissemination of Linezolid Resistant Staphylococcus aureus (LRSA within or across health care settings which demands continuous surveillance to determine the emergent risk of resistance strains and to establish guidelines for appropriate use. Clinical laboratories should confirm any LRSA preferably by a second method, prior to using linezolid for serious infections. Effective surveillance, more judicious use of this antibiotic, avoiding linezolid usage for empiric therapy in hospital acquired staphylococcus infections, optimization of the pharmacological parameters of the antibiotics in specific clinical situation, decreasing bacterial load by timely surgical debridement or drainage of collections, use of combination therapies would prevent the emergence of resistance to linezolid in staphylococcus aureus. [Int J Res Med Sci 2014; 2(4.000: 1253-1256

  12. Epidemiological survey and antibiotic resistance analysis of methicillin-resistant staphylococcus aureus in comprehensive hospitals from 2011 to 2014%综合性医院2011-2014年MRSA感染流行病学调查和耐药性分析

    Institute of Scientific and Technical Information of China (English)

    纵帅; 徐萍萍; 康海全; 冯倚帆; 郝婷婷; 徐银海

    2016-01-01

    Objective To retrospectively analyze the epidemiological characteristics and drug resistance of methicil-lin-resistant Staphylococcus aureus ( MRSA) which was isolated from nosocomial infection .Methods Clinical data a-bout MRSA infection in hospitals were collected from 2011 to 2014.Then, the detection rate, clinical distribution, sources of specimens and antibiotic resistance of MRSA were analyzed .Results The main departments where MRSA was detected were ICU ( including emergency ICU ) and Departments of Neurology , Neurosurgery , Pediatrics and Respiratory . MRSA infection was detected in 61.3%of sputum samples and 20.2%of blood samples.All MRSA strains were sensi-tive to vancomycin, linezolid, syncercid and teicoplanin, but resistant to the selected β-lactam antibiotics.More than 50%of the stains were resistant to other antibiotics .However , the ratio of MIC =2 mg/L of vancomycin to MRSA is gradually increased .Conclusion Hospital MRSA has a high infection rate and serious multiple antibiotic resistance , but no strain was resistant or intermediate to vancomycin .The monitoring and management to major distribution departments should be strengthened to prevent the outbreak .Patients with MRSA infection, whose MIC≥1.0 mg/L (broth microdilu-tion method), should be given more intensive monitoring and active antibiotic therapy .%目的:回顾性分析耐甲氧西林金黄色葡萄球菌( MRSA)医院感染的流行病学特征和耐药性特点。方法收集和统计2011—2014年徐州医学院附属医院MRSA感染的相关数据,分析其检出率、临床科室分布、标本来源和耐药性特点等。结果近4年MRSA的检出主要分布在ICU(含急诊ICU)、神经内科、神经外科、儿科和呼吸科等科室;检出标本中以痰液和血液为主,分别占61.3%和20.2%;对万古霉素、替考拉宁和利奈唑胺等100%敏感,对所选β-内酰胺类抗生素100%耐药,对其他抗生素耐药多在50%

  13. Fighting antibiotic resistance in the intensive care unit using antibiotics.

    Science.gov (United States)

    Plantinga, Nienke L; Wittekamp, Bastiaan H J; van Duijn, Pleun J; Bonten, Marc J M

    2015-01-01

    Antibiotic resistance is a global and increasing problem that is not counterbalanced by the development of new therapeutic agents. The prevalence of antibiotic resistance is especially high in intensive care units with frequently reported outbreaks of multidrug-resistant organisms. In addition to classical infection prevention protocols and surveillance programs, counterintuitive interventions, such as selective decontamination with antibiotics and antibiotic rotation have been applied and investigated to control the emergence of antibiotic resistance. This review provides an overview of selective oropharyngeal and digestive tract decontamination, decolonization of methicillin-resistant Staphylococcus aureus and antibiotic rotation as strategies to modulate antibiotic resistance in the intensive care unit.

  14. Depression of biofilm formation and antibiotic resistance by sarA disruption in Staphylococcus epidermidis

    Institute of Scientific and Technical Information of China (English)

    Ju-Hong Tao; Chang-Sheng Fan; Shan-E Gao; Hai-Jiao Wang; Guo-Xin Liang; Qing Zhang

    2006-01-01

    AIM: To study the effects of disruption of sarA gene on biofilm formation and antibiotic resistance of Staphylococcus epidermidis (S. epidermidis ).METHODS: In order to disrupt sarA gene, the doublecrossover homologous recombination was applied in S. epidermidis RP62A, and tetracycline resistance gene (tet) was used as the selective marker which was amplified by PCR from the pBR322 and inserted into the locus between sarA upstream and downstream,resulting in pBT2△sarA. By electroporation, the plasmid pBT2△sarA was transformed into S. epidermidis.Gene transcription was detected by real-time reverse transcription-PCR (RT-PCR). Determination of biofilm was performed in 96-well flat-bottomed culture plates, and antibiotic resistance was analyzed with test tube culture by spectrophotometry at 570 nm respectively.RESULTS: A sarA disrupted strain named S. epidermidis RP62A△sarA was constructed, which was completely defective in biofilm formation, while the sarA complement strain RP62A△sarA (pHPS9sarA) restored the biofilm formation phenotype. Additionally, the knockout of sarA resulted in decreased erythromycin and kanamycin resistance of S. epidermidis RP62A. Compared to the original strain, S. epidermidis RP62A△sarA had an increase of the sensitivity to erythromycin at 200-400 μg/mL and kanamycin at 200-800 μg/mL respectively.CONCLUSION: The knockout of sarA can result in the defect in biofilm formation and the decreased erythromycin and kanamycin resistance in S. epidermidis RP62A.

  15. Microbiological air quality in some kindergartens and antibiotic resistance of bacteria of the Staphylococcus spp. genus

    Directory of Open Access Journals (Sweden)

    Łukasz Kubera

    2015-02-01

    Full Text Available Background: Microbiological contamination of the air and the acquisition of the antibiotic resistance by pathogenic bacteria is a growing phenomenon that has a substantial impact on the quality of our health. This problem applies mainly to public areas where we spend a large part of our lives. This study was focused on the microbiological analysis of the air in some kindergartens and antibiotic resistance of bacteria of the Stephylococcus spp. genus. The identification of the isolated mould fungi has been also made. Material and Methods: Air samples were collected from classrooms in the seasonal cycle in the mornings and afternoons using 2 methods, sedimentation and impact. Air samples collected outside the kindergartens served as controls. Air quality assessments were based on the groups of indicator microorganisms, according to Polish standards. The susceptibility of isolated staphylococci was assessed with the disc-diffusion method, using 8 different classes of antibiotics, in line with the recommendations of the European Committee on Antimicrobial Susceptibility Testing (EUCAST. Results: The analyses show that, regardless of the method, the total number of heterothropic bacteria and staphylococci in the air of the analyzed kindergartens exceeded the allowable limits. There was no air pollution with the fungal infection. Based on the antibiogram, it was found that Staphylococcus spp. strains showed the highest sensitivity to chloramphenicol and the lowest to penicillin and gentamicin. Among the fungi moulds of the genus Cladosporium predominated. Conclusions: The results of the analyses highlight the need for regular health checks and further research to help identify biological factors that may significantly affect the quality of health of people living in public spaces. Med Pr 2015;66(1:49–56

  16. Staphylococcus aureus bacteremia.

    Science.gov (United States)

    Jensen, Allan Garlik

    2003-11-01

    Staphylococcus aureus bacteremia (SAB) is still associated with a high mortality, and knowledge on risk factors and the clinical and the therapeutic aspects of SAB is still limited. This thesis focuses on the clinical aspects of SAB and its metastatic infections. In a study of all patients with bacteremia in Copenhagen County October 1992 through April 1993 (study I) we emphasized previous findings, that S. aureus is one of the most frequent pathogens in bacteremia, and in a case control study also in Copenhagen County 1994-95 (study II) we demonstrated, that not only an inserted central venous catheter and nasal S. aureus carriage but also hyponatremia and anemia are important risk factors for hospital-acquired SAB (study II). Studies on the treatment of SAB have pointed out, that the eradication of a primary is important, but there are only limited clinical studies dealing with antibiotic treatment. By logistic regression analysis, we were able to demonstrate that focus eradication is essential, but also that treatment with dicloxacillin 1 g x 4 or 2 g x 3 are superior to 1 g x 3 (studie III), indicating that the time for serum concentration above the Minimal Inhibitory Concentration (MIC) for the bacteria plays a role in the outcome of SAB treatment. S. aureus osteomyelitis secondary to SAB is frequently observed. No other countries, however, have a centralized registration, which make it possible to evaluate a large number of these patients. Since 1960, The Staphylococcal Laboratory, Statens Serum Institut in Copenhagen, has registrated selected clinical informations from nearly all patients with positive blood cultures of S. aureus. Based on this registration, we were able to show an increased number of S. aureus osteomyelitis among older patients and a decreased number of S. aureus osteomyelitis of femur and tibia among younger infants in the period 1980-90 (study IV). By reviewing the records of a large number of patients with vertebral S. aureus

  17. Spread of invasive Spanish Staphylococcus aureus spa-type t067 associated with a high prevalence of the aminoglycoside-modifying enzyme gene ant(4')-Ia and the efflux pump genes msrA/msrB

    NARCIS (Netherlands)

    Perez-Vazquez, Maria; Vindel, Ana; Marcos, Carmen; Oteo, Jesus; Cuevas, Oscar; Trincado, Pilar; Bautista, Veronica; Grundmann, Hajo; Campos, Jose

    2009-01-01

    We carried out a nationwide study aimed at the determination of the molecular epidemiology and antibiotic resistance mechanisms of invasive Staphylococcus aureus in 21 Spanish hospitals. The distributions of molecular markers, including antibiotic resistance genes, were investigated in 203 S. aureus

  18. NVC-422 inactivates Staphylococcus aureus toxins.

    Science.gov (United States)

    Jekle, Andreas; Yoon, Jungjoo; Zuck, Meghan; Najafi, Ramin; Wang, Lu; Shiau, Timothy; Francavilla, Charles; Rani, Suriani Abdul; Eitzinger, Christian; Nagl, Markus; Anderson, Mark; Debabov, Dmitri

    2013-02-01

    Bacterial pathogens have specific virulence factors (e.g., toxins) that contribute significantly to the virulence and infectivity of microorganisms within the human hosts. Virulence factors are molecules expressed by pathogens that enable colonization, immunoevasion, and immunosuppression, obtaining nutrients from the host or gaining entry into host cells. They can cause pathogenesis by inhibiting or stimulating certain host functions. For example, in systemic Staphylococcus aureus infections, virulence factors such as toxic shock syndrome toxin 1 (TSST-1), staphylococcal enterotoxin A (SEA), and staphylococcal enterotoxin B (SEB) cause sepsis or toxic shock by uncontrolled stimulation of T lymphocytes and by triggering a cytokine storm. In vitro, these superantigens stimulate the proliferation of human peripheral blood mononuclear cells (PBMC) and the release of many cytokines. NVC-422 (N,N-dichloro-2,2-dimethyltaurine) is a broad-spectrum, fast-acting topical anti-infective agent against microbial pathogens, including antibiotic-resistant microbes. Using mass spectrometry, we demonstrate here that NVC-422 oxidizes methionine residues of TSST-1, SEA, SEB, and exfoliative toxin A (ETA). Exposure of virulence factors to 0.1% NVC-422 for 1 h prevented TSST-1-, SEA-, SEB-, and ETA-induced cell proliferation and cytokine release. Moreover, NVC-422 also delayed and reduced the protein A- and clumping factor-associated agglutination of S. aureus cultures. These results show that, in addition to its well-described direct microbicidal activity, NVC-422 can inactivate S. aureus virulence factors through rapid oxidation of methionines.

  19. Genome-Wide Transcriptional Profiling of the Response of Staphylococcus aureus to Cryptotanshinone

    Directory of Open Access Journals (Sweden)

    Haihua Feng

    2009-01-01

    Full Text Available Staphylococcus aureus (S. aureus strains with multiple antibiotic resistances are increasingly widespread, and new agents are required for the treatment of S. aureus. Cryptotanshinone (CT, a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated effective in vitro antibacterial activity against all 21 S. aureus strains tested in this experiment. Affymetrix GeneChips were utilized to determine the global transcriptional response of S. aureus ATCC 25923 to treatment with subinhibitory concentrations of CT. Transcriptome profiling indicated that the antibacterial action of CT may be associated with its action as active oxygen radical generator; S. aureus undergoes an oxygen-limiting state upon exposure to CT.

  20. Prevalence and antibiotic susceptibility of Staphylococcus aureus from bovine mastitis

    Directory of Open Access Journals (Sweden)

    C. G. Unakal and B. B. Kaliwal

    2010-04-01

    Full Text Available The primary objective of this study was to determine the prevalence and antimicrobial susceptibility of mastitic Staphylococcus aureus in dairy cows. Milk samples for microbiological culture were collected from dairy herds. A total of 105 samples were screened and 68 confirmed Staphylococcus aureus were obtained. The a, ß and non haemolytic activity revealed 20.58%, 75% and 4.41% respectively in 68 isolated strains of Staphylococcus aureus. Resistance of Staphylococcus aureus against 10 antimicrobial agents was tested using the disc diffusion method. The highest 86.76% isolates were resistant to penicillin followed by ampicillin 70.50%, amoxicillin 63.23%, gentamycin 47.05%, amikacin 30.80%, erythromycin 27.94%, Ciprofloxacin 26.47%, methicillin 23.52%, cefotaxime 20.58% and the lowest resistant was shown in ceftriaxone 19.11%. The study revealed that the increase in prevalence and antibiotic resistance pattern of the Staphylococcus aureus isolated from bovine mastitis. [Vet. World 2010; 3(2.000: 65-67

  1. Staphylococcus aureus Bacteraemia

    Directory of Open Access Journals (Sweden)

    James Price

    2010-01-01

    Full Text Available Staphylococcus aureus bacteraemia (SAB is commonly complicated by metastatic infection or relapse after treatment. Objectives. The study aim was to determine the role of bacterial, host, and management factors in development of complicated SAB. Methods. A prospectively-conducted observational study gathered data on predisposition, management and outcome of 100 consecutive SAB cases. Antibiotic susceptibilities and genetic lineage of bacterial isolates were determined. Further clinical and microbiological data were gathered on two retrospective series from 1999–2000 (n=57 and 2004 (n=116. Results. In the prospective cases, 27% met our definition of complicated disease. Expressed as RR and 95% CI, complicated disease was associated with diabetes (1.58, 1.00–2.48, injecting-drug use (5.48, 0.88–33.49, community-onset of symptoms (1.4, 1.02–1.92, and symptom duration ≥48 hours prior to starting effective antibiotic therapy (2.10, 1.22–3.61. Uncomplicated disease was associated with the presence of a central line (0.69, 0.55–0.88 and prompt removal of a primary focus (0.71, 0.57–0.90. Neither methicillin resistance nor genetic lineage was associated with complicated disease, but methicillin resistance was associated with higher mortality. Conclusions. This study demonstrates that clinical rather than microbial factors are the major determinants of SAB outcome and underscores the importance of early treatment.

  2. Flucloxacillin, still the empirical choice for putative Staphylococcus aureus infections in intensive care units in the Netherlands.

    NARCIS (Netherlands)

    Rijnders, M.I.; Deurenberg, R.H.; Boumans, M.L.; Hoogkamp-Korstanje, J.A.A.; Beisser, P.S.; Stobberingh, E.E.

    2009-01-01

    OBJECTIVES: To determine the usefulness of flucloxacillin as empirical therapy for putative Staphylococcus aureus infections in intensive care unit (ICU) patients in the Netherlands, the antibiotic resistance of S. aureus isolates from ICUs over a 13 year period was investigated. METHODS: From 1996

  3. [Protein toxins of Staphylococcus aureus].

    Science.gov (United States)

    Shamsutdinov, A F; Tiurin, Iu A

    2014-01-01

    Main scientific-research studies regarding protein bacterial toxins of the most widespread bacteria that belong to Staphylococcus spp. genus and in particular the most pathogenic species for humans--Staphylococcus aureus, are analyzed. Structural and biological properties of protein toxins that have received the name of staphylococcus pyrogenic toxins (PTSAg) are presented. Data regarding genetic regulation of secretion and synthesis of these toxins and 3 main regulatory genetic systems (agr--accessory gene regulator, xpr--extracellular protein regulator, sar--staphylococcal accessory regulator) that coordinate synthesis of the most important protein toxins and enzymes for virulence of S. aureus, are presented.

  4. 儿童吸入性和血源性金黄色葡萄球菌肺炎临床特点及其致病株耐药性分析%Clinical features of inhaled and blood-borne Staphylococcus aureus pneumonia and analysis of antibiotic resistance of the pathogen in children

    Institute of Scientific and Technical Information of China (English)

    张光莉; 刘茹; 张慧; 李颖; 张东伟; 李俊奇; 张思颖; 朱军; 罗征秀

    2014-01-01

    Objective To compare the clinical manifestations between inhaled and blood-borne Staphylococcus aureus pneumonia (SAP) and the antibiotic resistance between the isolates of inhaled and blood-borne Staphylococcus aureus. Methods The clinical data of 44 pediatric SAP cases in the Children's Hospital, Chongqing Medical University from January 2008 to December 2013 were retrospectively analyzed. Twenty-four cases were identified as inhaled SAP, and 20 cases as blood-borne SAP. Results Inhaled SAP was more common in children younger than 3 years of age, while blood-borne SAP was more prevalent in children older than 6 years of age. Patients with inhaled SAP had signiifcantly higher incidence rates of cough, wheeze, moist rales, dyspnea and empyema than those with blood-borne SAP (P<0.05). The patients with blood-borne SAP were more vulnerable to severe fever, unconsciousness, dysfunction of liver and kidney, pyogenic osteomyelitis, septic arthritis, sepsis, and abscess of skin and soft tissues (P<0.05). Inhaled SAP isolates had signiifcantly higher rates of resistance to amoxicillin/clavulanic acid, oxacillin, and cefoxitin than blood-borne SAP isolates (P<0.05), while the latter had a higher rate of resistance to cotrimoxazole (P<0.05). Conclusions Inhaled SAP often occurs in children younger than 3 years of age, and the respiratory manifestations are commonly seen. Blood-borne SAP often occurs in children older than 6 years of age, with the infectious-toxic symptoms that result in multiple organ infection and dysfunction. The isolates of inhaled and blood-borne SAP have different antibiograms.%目的:比较吸入性和血源性金黄色葡萄球菌肺炎(Staphy1ococcus aureus pneumonia, SAP)的临床特点及分离菌株的耐药性。方法回顾分析该院2008年1月至2013年12月确诊为SAP的44例患儿的临床资料。44例患儿中,24例为吸入性感染,20例为血源性感染。结果吸入性SAP以3岁以下婴幼儿多见,血源性SAP以6

  5. Phytochemical Analysis, Antibacterial Activity of Marrubium vulgare L against Staphylococcus aureus in vitro

    OpenAIRE

    Saeide Saeidi; Mohammad Bokaeian; Elham Saboori; Abbas Ali Niazi; Negar Amini-Borojeni; Hamde Khaje; Saphora Bazi

    2014-01-01

    Background: Herbal medicines are the major remedy in traditional medical systems and made a great contribution in maintaining human health and in preventing many infectious diseases. The present study was carried out to determine the potential antibacterial effect of ethanol extracts and essential oil of Marrubium vulgare L. against Staphylococcus aureus which is antibiotic resistant. Materials and Methods: All 17 strains of S. aureus isolated from nose and throat sample from 160 healthy s...

  6. Staphylococcus aureus CC398

    DEFF Research Database (Denmark)

    Price, Lance B.; Stegger, Marc; Hasman, Henrik

    2012-01-01

    -associated MRSA possessing three different staphylococcal cassette chromosome mec element (SCCmec) types (IV, V, and VII-like) including nine subtypes. The human-associated isolates from the basal clades carried phages encoding human innate immune modulators that were largely missing among the livestock...... by densely concentrated animals and routine antibiotic use, which may facilitate the emergence of novel antibiotic-resistant zoonotic pathogens. Our findings strongly support the idea that livestock-associated MRSA CC398 originated as MSSA in humans. The jump of CC398 from humans to livestock was accompanied...... by the loss of phage-carried human virulence genes, which likely attenuated its zoonotic potential, but it was also accompanied by the acquisition of tetracycline and methicillin resistance. Our findings exemplify a bidirectional zoonotic exchange and underscore the potential public health risks of widespread...

  7. Antibiotic Resistance

    Science.gov (United States)

    ... lives. But there is a growing problem of antibiotic resistance. It happens when bacteria change and become able ... resistant to several common antibiotics. To help prevent antibiotic resistance Don't use antibiotics for viruses like colds ...

  8. Phagocytosis and killing of Staphylococcus aureus by human neutrophils.

    Science.gov (United States)

    Lu, Thea; Porter, Adeline R; Kennedy, Adam D; Kobayashi, Scott D; DeLeo, Frank R

    2014-01-01

    Neutrophils are essential for host defense against Staphylococcus aureus infections. Although significant progress has been made, our understanding of neutrophil interactions with S. aureus remains incomplete. To provide a more comprehensive view of this process, we investigated phagocytosis and killing of S. aureus by human neutrophils using varied assay conditions in vitro. A greater percentage of bacteria were internalized by adherent neutrophils compared to those in suspension, and, unexpectedly, uptake of S. aureus by adherent neutrophils occurred efficiently in the absence of opsonins. An antibody specific for S. aureus promoted uptake of unopsonized bacteria in suspension, but had little or no capacity to enhance phagocytosis of S. aureus opsonized with normal human serum or by adherent neutrophils. Collectively, these results indicate that assay conditions can have a significant influence on the phagocytosis and killing of S. aureus by neutrophils. More importantly, the results suggest a vaccine approach directed to enhance opsonophagocytosis alone is not sufficient to promote increased killing of S. aureus by human neutrophils. With the emergence and reemergence of antibiotic-resistant microorganisms, establishing parameters that are optimal for studying neutrophil-S. aureus interactions will pave the way towards developing immune-directed strategies for anti-staphylococcal therapies.

  9. Phenotype switching is a natural consequence of Staphylococcus aureus replication.

    Science.gov (United States)

    Edwards, Andrew M

    2012-10-01

    The pathogen Staphylococcus aureus undergoes phenotype switching in vivo from its normal colony phenotype (NCP) to a slow-growing, antibiotic-resistant small-colony-variant (SCV) phenotype that is associated with persistence in host cells and tissues. However, it is not clear whether phenotype switching is the result of a constitutive process that is selected for under certain conditions or is triggered by particular environmental stimuli. Examination of cultures of diverse S. aureus strains in the absence of selective pressure consistently revealed a small gentamicin-resistant SCV subpopulation that emerged during exponential-phase NCP growth and increased in number until NCP stationary phase. Treatment of replicating bacteria with the antibiotic gentamicin, which inhibited NCP but not SCV replication, resulted in an initial decrease in SCV numbers, demonstrating that SCVs arise as a consequence of NCP replication. However, SCV population expansion in the presence of gentamicin was reestablished by selection of phenotype-stable SCVs and subsequent SCV replication. In the absence of selective pressure, however, phenotype switching was bidirectional and occurred at a high frequency during NCP replication, resulting in SCV turnover. In summary, these data demonstrate that S. aureus phenotype switching occurs via a constitutive mechanism that generates a dynamic, antibiotic-resistant subpopulation of bacteria that can revert to the parental phenotype. The emergence of SCVs can therefore be considered a normal part of the S. aureus life cycle and provides an insurance policy against exposure to antibiotics that would otherwise eliminate the entire population.

  10. Exfoliative toxin serotype genes and antibiotic resistance of staphylococcus aureus isolated from children with staphylococcal scalded skin syndrome%葡萄球菌性烫伤样皮肤综合征的致病金黄色葡萄球菌剥脱毒素基因型及耐药研究

    Institute of Scientific and Technical Information of China (English)

    苏怡帆; 王华; 肖异珠; 欧阳莹; 李咏梅; 罗晓燕; 谭琦; 向娟

    2008-01-01

    Objective To investigate the exfoliative toxin serotype genes and antibiotic resistance of Staphylococcus aureus (SA) isolated from children with staphylococcal scalded skin syndrome (SSSS). Methods In total, 108 strains of SA were isolated from 36 patients with SSSS, 36 patients with impetigo and 36 patients with abscess. Multiplex PCR was used to detect the staphylococcal exfoliative toxin A, B and D genes, Kirby-Baner method to test the susceptibilities of SA strains to 20 antibiotics. Results All the 36 SA isolates from SSSS patients were ET-positive, and 2 (6%) produced ETA, 7 (19%) ETB, 27 (75%) both ETA and ETB; of the 36 isolates from patients with impetigo, 78% produced ET, and 14% produced ETA, 64% produced both ETA and ETB, while no single ETB-producing strain was found; ET was detected in only one (2.8%) SA isolate from abscess patients, which produced both ETA and ETB. ETD was detected in none of the SA isolates. There was a statistical difference in the distribution of ET serotype among the three diseases (χ2=89.4, P < 0.01) and the proportion of ET-producing strains in SSSS group was signifi-cantly higher than that in impetigo group (χ2=9.0, P < 0.01) and abscess group (χ2= 68.1, P < 0.01). All the SA isolates were highly resistant to penicilin, ampicillin, macrolides and clindamycin, but sensitive to other 15 common antibiotics such as cephalosporin. Two strains of MRSA were found in patients with abscess. Conclusion In Chongqing, ET-producing SA is the common pathogenic bacteria of SSSS and impetigo, and most of SA strains produce both ETA and ETB.%目的 探讨葡萄球菌性烫伤样皮肤综合征(SSSS)致病的金黄色葡萄球菌(简称金葡菌)分泌表皮剥脱毒素(ET)的主要类型及耐药情况.方法 108株金葡菌分离自SSSS(36例)、脓疱疮(36例)及皮肤脓肿(36例).用多重PCR法测定致病金葡菌菌株产ETA、ETB、ETD基因型,Kirby-Bauer纸片法检测其对20种抗生素的敏感性.结果 36

  11. Gene typing and antibiotic resistance of methicillin-resistant Staphylococcus aureus isolated from lower respiratory tract at two hospitals in Shanghai%上海不同级别医院下呼吸道耐甲氧西林金黄色葡萄球菌的基因型及其耐药性

    Institute of Scientific and Technical Information of China (English)

    王仁; 万欢英; 时国朝; 李敏; 韩立中; 金晓燕; 孙晴; 何平; 周敏

    2016-01-01

    目的 研究上海不同级别医院下呼吸道标本中耐甲氧西林金黄色葡萄球菌(MRSA)的基因型及耐药性.方法 研究对象为2013年1月至2014年6月2家不同级别医院(瑞金医院及同仁医院)155例住院患者,男108例,女47例,平均年龄为(68±17)岁.收集患者下呼吸道痰液标本中分离的155株MRSA菌株,用PCR法对所有菌株进行多位点序列分型(MLST)和葡萄球菌A蛋白(Spa)分型,采用VITEK-32全自动微生物分析仪进行13种抗生素的体外药敏试验,并采用Fisher确切概率法进行统计学分析.结果 从155株MRSA菌株中共分离出28种MLST-spa分子克隆分型,其中ST764-t002(64株,41.3%)、ST239-t037(27株,17.4%)和ST239-t030(16株,10.3%)为主要型别.所有MRSA菌株对利奈唑胺、万古霉素、替考拉宁均敏感,敏感度均为100%,对磺胺甲噁唑/甲氧苄啶和利福平耐药度较低,敏感度分别为83.9%(130株)和83.2%(129株),但对青霉素、苯唑西林及头孢唑林显示高度耐药或全耐药,敏感度分别为0%(0株)、0%(0株)及3.9%(6株).ST239-t037型对磺胺甲噁唑/甲氧苄啶的耐药度高于其他型别,ST239-t030对利福平的耐药度高于其他型别,差异均有统计学意义(P<0.001).155例患者平均住院时间为(97±84)d,78例(50.3%)患者有机械通气史,108例(69.7%)有侵袭性操作史,136例(87.1%)患者病程中使用过广谱抗生素.通过对2家医院患者的危险因素分析,年龄、住院天数、吸烟史、慢阻肺病史、机械通气及手术史比较差异有统计学意义(P<0.05).结论 瑞金医院和同仁医院分离出的MRSA菌株多为多重耐药菌,共有28种MLST-spa克隆型,不同基因型的药敏试验谱有所差异.%Objective To study the genotyping characteristics and antibiotic resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolated from lower respiratory tract at 2 different level hospitals in Shanghai.Methods The subjects included 155

  12. An overview of Staphylococcus epidermidis and Staphylococcus aureus with a focus on developing countries.

    Science.gov (United States)

    Chessa, Daniela; Ganau, Giulia; Mazzarello, Vittorio

    2015-07-04

    Most nosocomial infections by Staphylococcus epidermidis and Staphylococcus aureus have gained considerable attention due to an increase of infections caused by these strains that have been reported in recent years throughout the world. Most notably, it is important to underline the presence of S. epidermidis and S. aureus in the human epithelia microflora and to highlight that it is impossible to eradicate them from humans. There are various virulence factors that normally sustain the infection life cycle, such as antibiotic resistance (methicillin resistance). Furthermore, it is important to evaluate the usefulness of typing the spa gene from isolated strains in order to study genotypes and geographical distributions. In the present review, different cases related to patients infected by Staphylococci and an overview of this problem worldwide are reported.

  13. Monoclonal Antibody Targeting Staphylococcus aureus Surface Protein A (SasA) Protect Against Staphylococcus aureus Sepsis and Peritonitis in Mice.

    Science.gov (United States)

    Yang, Yilong; Qian, Mengying; Yi, Shaoqiong; Liu, Shuling; Li, Bing; Yu, Rui; Guo, Qiang; Zhang, Xiaopeng; Yu, Changming; Li, Jianmin; Xu, Junjie; Chen, Wei

    2016-01-01

    Epidemic methicillin-resistant Staphylococcus aureus (MRSA) imposes an increasing impact on public health. Due to multi-antibiotics resistance in MRSA strains, there is an urgent need to develop novel therapeutics such as effective monoclonal antibodies (mAbs) against MRSA infections. Staphylococcus aureus surface protein A (SasA), a large surface-located protein (~240 kDa), is one of MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) and a potential target for immunotherapeutic approaches against S. aureus infections. In the present study, we analyzed the sequence of SasA with bioinformatics tools and generated a protective monoclonal antibody (2H7) targeting the conserved domain of SasA. 2H7 was shown to recognize wild-type S. aureus and promote opsonophagocytic killing of S. aureus. In both sepsis and peritoneal infection models, prophylactic administration of 2H7 improved the survival of BALB/c mice challenged by S. aureus strain USA300 and ST239 (prevalent MRSA clones in North America and Asian countries, respectively) and enhanced bacterial clearance in kidneys. Additionally, 2H7 prophylaxis prevented the formation of intraperitoneal abscess in a murine model of peritoneal infection and therapeutic administration of 2H7 showed protective efficacy in a murine sepsis model. Our results presented here provide supporting evidences that an anti-SasA mAb might be a potential component in an antibody-based immunotherapeutic treatment of MRSA infections.

  14. The Lytic SA Phage Demonstrate Bactericidal Activity against Mastitis Causing Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Hamza Ameer

    2016-01-01

    Full Text Available Staphylococcus aureus is the major causative agent of mastitis among dairy animals as it causes intramammary gland infection. Due to antibiotic resistance and contamination of antibiotics in the milk of diseased animals; alternative therapeutic agents are required to cure mastitis. Lytic bacteriophages and their gene products can be potential therapeutic agents against bacteria as they are host specific and less harmful than antibiotics. In this study, Staphylococcus aureus were isolated from milk samples of the infected animals and identified biochemically. SA phage was isolated from sewage water showing lytic activity against Staphylococcus aureus isolates. The highest lytic activity of bacteriophages was observed at 37°C and pH 7, and the most suitable storage condition was at 4°C. SA phage efficiently reduced bacterial growth in the bacterial reduction assay. The characterization and bacterial growth reduction activity of the bacteriophages against Staphylococcus aureus signifies their underlying potential of phage therapy against mastitis.

  15. Analysis of Antibiotics Resistance of Staphylococcus aureus Isolated from Bovine Mastitis in Shandong Province and Detection of mecA Gene%山东省牛源金黄色葡萄球菌耐药谱分析及mecA耐药基因检测

    Institute of Scientific and Technical Information of China (English)

    李秀梅; 杨宏军; 肖红; 王慧红; 王青泉; 何洪彬; 宋玲玲; 侯佩莉; 田晶

    2012-01-01

    采用纸片扩散法测定金黄色葡萄球菌(以下简称金葡菌)对6种抗生素的敏感性.结果表明,在测定的121株金葡菌中,耐苯唑西林金葡菌(MRSA)为26株,占21.5%;对苯唑西林敏感菌(MSSA)为93株,占76.9%;中介菌株为2株,占1.6%.金葡菌对6种抗生素耐药率最低的是头孢噻肟为2株,占1.6%.mecA基因的PCR扩增结果显示:所有的MSSA mecA基因均阴性,中介株mecA基因阳性1株,而MRSA中mecA基因阳性株为9株.MSSA对大部分抗生素仍保持良好的敏感性,而MRSA表现为多重耐药性,PCR技术可以作为快速检测金葡菌耐药基因的有效方法.%The susceptibility of 121 strains of Staphylococcus aureus isolated from bovine mastitis to six kinds of antibiotics was determined by disk diffusion method. The results showed that 26 strains occupied 21. 5% were methicillin - resistant Staphylococcus aureus (MRSA), while 93 strains occupied 76. 9% were susceptible to oxacillin( MSSA), and 2 strains were intermediary. There were only 2 strains of Staphylococcus aureus had the lowest resistant rate to cefotaxime, which occupied 1. 6%. The PCR results showed that the mecA gene of all oxacillin - sensitive strains were negative,. While that of one intermediary strain and 9 MRSA strains was positive. The MSSA strains still maintained good susceptibility to most of antibiotics, but the MRSA strains showed multi - drug resistance. PCR technology can be used as a rapid and effective way to detectthe drug resistant genes of Staphylococcus aureus.

  16. Undetectable bacterial resistance to phage lytic proteins from the Staphylococcus aureus bacteriophage vB_SauS-phiIPLA88

    Science.gov (United States)

    The increase in antibiotic resistance world-wide revitalized the interest in the use of phage lysins to combat pathogenic bacteria. In this work, we tested for the emergence of resistant Staphylococcus aureus to any of three phage lytic proteins constructs. The investigated cell wall lytic enzymes w...

  17. Pathogenesis of Staphylococcus aureus abscesses.

    Science.gov (United States)

    Kobayashi, Scott D; Malachowa, Natalia; DeLeo, Frank R

    2015-06-01

    Staphylococcus aureus causes many types of human infections and syndromes-most notably skin and soft tissue infections. Abscesses are a frequent manifestation of S. aureus skin and soft tissue infections and are formed, in part, to contain the nidus of infection. Polymorphonuclear leukocytes (neutrophils) are the primary cellular host defense against S. aureus infections and a major component of S. aureus abscesses. These host cells contain and produce many antimicrobial agents that are effective at killing bacteria, but can also cause non-specific damage to host tissues and contribute to the formation of abscesses. By comparison, S. aureus produces several molecules that also contribute to the formation of abscesses. Such molecules include those that recruit neutrophils, cause host cell lysis, and are involved in the formation of the fibrin capsule surrounding the abscess. Herein, we review our current knowledge of the mechanisms and processes underlying the formation of S. aureus abscesses, including the involvement of polymorphonuclear leukocytes, and provide a brief overview of therapeutic approaches.

  18. CHROMOSOMAL MAPPING IN STRAINS OF STAPHYLOCOCCUS AUREUS,

    Science.gov (United States)

    STAPHYLOCOCCUS AUREUS , CHROMOSOMES), (*CHROMOSOMES, MAPPING), NITROSO COMPOUNDS, GUANIDINES, GENETICS, MUTATIONS, DRUGS, TOLERANCES(PHYSIOLOGY), TEST METHODS, DEOXYRIBONUCLEIC ACIDS, INHIBITION, RESISTANCE(BIOLOGY).

  19. FabH Mutations Confer Resistance to FabF-Directed Antibiotics in Staphylococcus aureus

    OpenAIRE

    Parsons, Joshua B.; Yao, Jiangwei; Frank, Matthew W.; Rock, Charles O.

    2014-01-01

    Delineating the mechanisms for genetically acquired antibiotic resistance is a robust approach to target validation and anticipates the evolution of clinical drug resistance. This study defines a spectrum of mutations in fabH that render Staphylococcus aureus resistant to multiple natural products known to inhibit the elongation condensing enzyme (FabF) of bacterial type II fatty acid synthesis. Twenty independently isolated clones resistant to platensimycin, platencin, or thiolactomycin were...

  20. Modulation of drug resistance in Staphylococcus aureus by extract of mango (Mangifera indica L., Anacardiaceae) peel

    OpenAIRE

    Susy Mary Souto de Oliveira; Falcão-Silva, Vivyanne S; Siqueira-Junior,José P.; Maria José de Carvalho Costa; Margareth de Fátima F. Melo Diniz

    2011-01-01

    In an ongoing project to evaluate natural compounds isolated from by-products or wastes from vegetables and fruits (edible plants) as modulators of antibiotic resistance, ethanol extract from mango peel was investigated using Staphylococcus aureus strains possessing efflux mechanisms of resistance to norfloxacin, erythromycin and tetracycline. The minimum inhibitory concentrations (MIC) of the antibiotics were determined by the micro dilution assay in the absence and in the presence of sub-in...

  1. In Vitro Antibacterial and Antibiotic Resistance Modifying Effect of Bioactive Plant Extracts on Methicillin-Resistant Staphylococcus epidermidis

    Directory of Open Access Journals (Sweden)

    Romana Chovanová

    2013-01-01

    Full Text Available The crude extracts of plants from Asteraceae and Lamiaceae family and essential oils from Salvia officinalis and Salvia sclarea were studied for their antibacterial as well as antibiotic resistance modifying activity. Using disc diffusion and broth microdilution assays we determined higher antibacterial effect of three Salvia spp. and by evaluating the leakage of 260 nm absorbing material we detected effect of extracts and, namely, of essential oils on the disruption of cytoplasmic membrane. The evaluation of in vitro interactions between plant extracts and oxacillin described in terms of fractional inhibitory concentration (FIC indices revealed synergistic or additive effects of plant extracts and clearly synergistic effects of essential oil from Salvia officinalis with oxacillin in methicillin-resistant Staphylococcus epidermidis.

  2. The Recombinant Bacteriophage Endolysin HY-133 Exhibits In Vitro Activity against Different African Clonal Lineages of the Staphylococcus aureus Complex, Including Staphylococcus schweitzeri

    Science.gov (United States)

    Idelevich, Evgeny A.; Schaumburg, Frieder; Knaack, Dennis; Scherzinger, Anna S.; Mutter, Wolfgang; Peters, Georg; Peschel, Andreas

    2016-01-01

    HY-133 is a recombinant bacteriophage endolysin with bactericidal activity against Staphylococcus aureus. Here, HY-133 showed in vitro activity against major African methicillin-susceptible and methicillin-resistant S. aureus lineages and ceftaroline/ceftobiprole- and borderline oxacillin-resistant isolates. HY-133 was also active against Staphylococcus schweitzeri, a recently described species of the S. aureus complex. The activity of HY-133 on the tested isolates (MIC50, 0.25 μg/ml; MIC90, 0.5 μg/ml; range, 0.125 to 0.5 μg/ml) was independent of the species and strain background or antibiotic resistance. PMID:26833148

  3. Staphylococcus aureus isolated from tonsillectomized adult patients with recurrent tonsillitis.

    Science.gov (United States)

    Katkowska, Marta; Garbacz, Katarzyna; Stromkowski, Józef

    2017-01-01

    The aim of this study was to analyze the prevalence and antibiotic resistance of Staphylococcus aureus strains from 118 tonsillectomized adults due to recurrent tonsillitis (RT). The study included strains isolated from the tonsillar surface prior to tonsillectomy, recovered from the tonsillar core at the time of surgery, and from the posterior throat 2-4 weeks after the procedure. Susceptibility of isolates to 19 antibiotics was tested in line with the Clinical and Laboratory Standards Institute recommendations. Irrespective of the stage, the most commonly isolated bacteria were gram-positive cocci, and among them S. aureus. The tonsillar core was the most common site of S. aureus isolation (30.5%), followed by the tonsillar surface (10.8%) and the posterior pharynx (5.9%). This difference turned out to be statistically significant (p aureus seems to be the most common pathogen isolated from patients tonsillectomized due to RT. Staphylococcal isolates associated with RT are present mostly within the tonsillar core and susceptible to most antibiotics. They are typically isolated from patients between 21 and 30 years of age. Tonsillectomy results in less frequent isolation of S. aureus strains.

  4. Analysis of the features of 45 identified CRISPR loci in 32 Staphylococcus aureus.

    Science.gov (United States)

    Yang, Siyu; Liu, Jing; Shao, Fuye; Wang, Pengfei; Duan, Guangcai; Yang, Haiyan

    2015-08-28

    Staphylococcus aureus (S. aureus) is a common pathogen that can cause serious infections, even death. Because of the horizontal gene transfer (HGT) of antibiotic resistance genes, the drug resistant condition is becoming increasingly prevalent. Recently, an adaptive immunity system, named clustered regularly interspaced short palindromic repeats (CRISPR), was discovered and demonstrated to confer a defense against foreign invading elements that may carry the antibiotic resistance genes. In this study, we reveal the features of 45 identified CRISPR loci and the CRISPR associated gene (Cas) in 32 S. aureus strains from CRISPR database. Five spacers of S. aureus 08BA02176 and MSHR1132 were homologous with foreign genetic sequences from phages or plasmids, even containing a spacer sequence identical to part of some phages' genomes containing lukPV gene that encodes the PVL toxin. Many S. aureus strains with the same CRISPR type shared the same MLST type. CRISPR loci that had 3 or more similar protein loci mostly belonged to the same CRISPR type. We came to the conclusion that the CRISPR/Cas of strains 08BA02176 and MSHR1132 were inherited from a common ancestor or recombined from Staphylococcus lugdunensis. CRISPR loci can be mobilized and can transfer among different but closely related species, and the same types of MLST strains exhibit a higher affinity to the same types of CRISPR loci. Bacteriophages may be the predominant challenge facing S. aureus. The CRISPR/Cas structure may limit the transmission of bacterial virulence among S. aureus.

  5. Antibiotic-Resistant Bacteria.

    Science.gov (United States)

    Longenecker, Nevin E.; Oppenheimer, Dan

    1982-01-01

    A study conducted by high school advanced bacteriology students appears to confirm the hypothesis that the incremental administration of antibiotics on several species of bacteria (Escherichia coli, Staphylococcus epidermis, Bacillus sublitus, Bacillus megaterium) will allow for the development of antibiotic-resistant strains. (PEB)

  6. Molecular Characterization of Staphylococcus aureus Isolates Transmitted between Patients with Buruli Ulcer.

    Directory of Open Access Journals (Sweden)

    Nana Ama Amissah

    Full Text Available Buruli ulcer (BU is a skin infection caused by Mycobacterium ulcerans. The wounds of most BU patients are colonized with different microorganisms, including Staphylococcus aureus.This study investigated possible patient-to-patient transmission events of S. aureus during wound care in a health care center. S. aureus isolates from different BU patients with overlapping visits to the clinic were whole-genome sequenced and analyzed by a gene-by-gene approach using SeqSphere(+ software. In addition, sequence data were screened for the presence of genes that conferred antibiotic resistance.SeqSphere(+ analysis of whole-genome sequence data confirmed transmission of methicillin resistant S. aureus (MRSA and methicillin susceptible S. aureus among patients that took place during wound care. Interestingly, our sequence data show that the investigated MRSA isolates carry a novel allele of the fexB gene conferring chloramphenicol resistance, which had thus far not been observed in S. aureus.

  7. Staphylococcus aureus in the community: colonization versus infection.

    Directory of Open Access Journals (Sweden)

    Maureen Miller

    Full Text Available BACKGROUND: Antibiotic-resistant Staphylococcus aureus infections have increased dramatically in the community, yet S. aureus nasal colonization has remained stable. The objectives of this study were to determine if S. aureus colonization is a useful proxy measure to study disease transmission and infection in community settings, and to identify potential community reservoirs. METHODOLOGY/PRINCIPAL FINDINGS: Randomly selected households in Northern Manhattan, completed a structured social network questionnaire and provided nasal swabs that were typed by pulsed field gel electrophoresis to identify S. aureus colonizing strains. The main outcome measures were: 1 colonization with S. aureus; and 2 recent serious skin infection. Risk factor analyses were conducted at both the individual and the household levels; logistic regression models identified independent risks for household colonization and infection. RESULTS: 321 surveyed households contained 914 members. The S. aureus prevalence was 25% and MRSA was 0.4%. More than 40% of households were colonized. Recent antibiotic use was the only significant correlate for household colonization (p = .002. Seventy-eight (24% households reported serious skin infection. In contrast with colonization, five of the six risk factors that increased the risk of skin infection in the household at the univariate level remained independently significant in multivariable analysis: international travel, sports participation, surgery, antibiotic use and towel sharing. S. aureus colonization was not significantly associated with serious skin infection in any analysis. Among multiperson households with more than one person colonized, 50% carried the same strain. CONCLUSIONS/SIGNIFICANCE: The lack of association between S. aureus nasal colonization and serious skin infection underscores the need to explore alternative venues or body sites that may be crucial to transmission. Moreover, the magnitude of colonization and

  8. Staphylococcus aureus nasal carriage in hemodialysis centers of Fez, Morocco.

    Directory of Open Access Journals (Sweden)

    Idrissa Diawara

    2014-06-01

    Full Text Available Staphylococcus aureus (S. aureus nasal carriage may be responsible for some serious infections in hemodialyzed patients. The main target of this study was to estimate the prevalence of S. aureus nasal carriage in hemodialysis outpatients and medical staff in hemodialysis centers specifically in Fez region. The second target is to identify the risks of colonization, resistance pattern of isolates and their virulence toxin genes.Nasal swab specimens were obtained from 143 hemodialyzed outpatients and 32 medical staff from January to June 2012. Each participant completed a short questionnaire. Nasal carriage of S. aureus was demographically related (age, gender, hemodialysis duration, comorbidity (diabetes, malignancy and exposure to health care (dialysis staff, hospitalization. PCR (Polymerase Chain Reaction were used on all the isolates in the research of twelve staphylococcal enterotoxins genes. Also the PCR was used to investigate on the three factors epidermal cell differentiation inhibitors; three exfoliatin toxins; two leukotoxins; the toxic shock syndrome toxin-1 and the hemolysin beta genes.Nasal screening revealed 38.16%, 50% and 18.75% S. aureus carries in chronic, acute hemodialysis patients and medical staff, respectively. Only young participants were likely to be S. aureus carries (p = 0.002. But there were no gender differences between the isolate carriers and non-carriers or some comorbidity factors such as viral hepatitis B and C, HIV (Human Immunodeficiency Virus infections, diabetes, chronic smoking, recent hospitalization or antibiotic therapy. Out of all isolates, only one (1.61% was methicillin-resistant and Twenty-one (33.87% had at least two virulence toxin genes.Knowledge and monitoring of antibiotic resistance profile and virulence of S. aureus carriage are essential in the treatment of infections generated by this pathogen, as well as in the control of clonal dissemination and prevent the spread of S. aureus resistance.

  9. Exfoliative Toxins of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Michal Bukowski

    2010-05-01

    Full Text Available Staphylococcus aureus is an important pathogen of humans and livestock. It causes a diverse array of diseases, ranging from relatively harmless localized skin infections to life-threatening systemic conditions. Among multiple virulence factors, staphylococci secrete several exotoxins directly associated with particular disease symptoms. These include toxic shock syndrome toxin 1 (TSST-1, enterotoxins, and exfoliative toxins (ETs. The latter are particularly interesting as the sole agents responsible for staphylococcal scalded skin syndrome (SSSS, a disease predominantly affecting infants and characterized by the loss of superficial skin layers, dehydration, and secondary infections. The molecular basis of the clinical symptoms of SSSS is well understood. ETs are serine proteases with high substrate specificity, which selectively recognize and hydrolyze desmosomal proteins in the skin. The fascinating road leading to the discovery of ETs as the agents responsible for SSSS and the characterization of the molecular mechanism of their action, including recent advances in the field, are reviewed in this article.

  10. 21 CFR 866.3700 - Staphylococcus aureus serological reagents.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Staphylococcus aureus serological reagents. 866... Staphylococcus aureus serological reagents. (a) Identification. Staphylococcus aureus serological reagents are... epidemiological information on these diseases. Certain strains of Staphylococcus aureus produce an...

  11. Study of antibiotic resistance of staph aureus and coagulase negative staphylococci isolated from patient samples

    Directory of Open Access Journals (Sweden)

    M Anvary

    2006-04-01

    Full Text Available Introduction: Drug resistant Staphylococci are the most important agents of nosocomial infections. In this survey, effect of different antibiotics on these bacteria and their drug resistance was investigated. Methods: The study included 500 strains of Staphylococci. Minimum Inhibitory Concentrations of all antibiotics was determined by the broth macro dilution technique and standard methods from the National Committee for Clinical Laboratory Standards. Result : Oxacillin resistance of S. aureus was 14.2% and that of coagulase-negative staphylococci was 53.4%. The activity of different antibiotics is presented in detail. Conclusion: Surveillance of strains resistant to methicillin is necessary.

  12. Phenotypic and genotypic antimicrobial resistance traits of foodborne Staphylococcus aureus isolates from Shanghai.

    Science.gov (United States)

    Xu, Jie; Shi, Chunlei; Song, Minghui; Xu, Xuebin; Yang, Puyu; Paoli, George; Shi, Xianming

    2014-04-01

    Staphylococcus aureus is a recognized pathogen in humans, which causes nosocomial infections and food poisoning. The transmission of antibiotic resistant S. aureus (ARSA), especially methicillin-resistant S. aureus, between food products and humans has become a serious problem. Hence, it is necessary to monitor S. aureus through the food supply chain. In this study, the disk diffusion method and epsilometer test were performed to determine the prevalence of ARSA in 78 foodborne isolates using 18 antibiotics. The highest resistance frequency was found for penicillin G (74.4%), followed by erythromycin (59.0%) and clindamycin (44.9%), whereas no vancomycin-resistant isolates were found. The 78 isolates could be subtyped into 31 resistance profiles and 11 clusters based on their antimicrobial susceptibility. Furthermore, Polymerase chain reaction (PCR) screening for the presence of 13 genes conferring antibiotic resistance was conducted. The presence of resistance genes was relatively high: blaTEM (80.8%), ermB (41.0%), grlA (38.5%), ermC (35.9%), and aac6'/aph2" (35.9%). The incidence of antibiotic resistance was significantly correlated to food types (p = 0.018), with isolates from meat and raw milk more resistant to antibiotics than those from frozen food and vegetables.

  13. Staphylococcus aureus and hand eczema severity

    DEFF Research Database (Denmark)

    Haslund, P; Bangsgaard, N; Jarløv, J O

    2009-01-01

    BACKGROUND: The role of bacterial infections in hand eczema (HE) remains to be assessed. OBJECTIVES: To determine the prevalence of Staphylococcus aureus in patients with HE compared with controls, and to relate presence of S. aureus, subtypes and toxin production to severity of HE. METHODS......: Bacterial swabs were taken at three different visits from the hand and nose in 50 patients with HE and 50 controls. Staphylococcus aureus was subtyped by spa typing and assigned to clonal complexes (CCs), and isolates were tested for exotoxin-producing S. aureus strains. The Hand Eczema Severity Index...... was used for severity assessment. RESULTS: Staphylococcus aureus was found on the hands in 24 patients with HE and four controls (P hands...

  14. Direction of aminoacylated transfer RNAs into antibiotic synthesis and peptidoglycan-mediated antibiotic resistance.

    Science.gov (United States)

    Shepherd, Jennifer; Ibba, Michael

    2013-09-17

    Prokaryotic aminoacylated-transfer RNAs often need to be efficiently segregated between translation and other cellular biosynthetic pathways. Many clinically relevant bacteria, including Streptococcus pneumoniae, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa direct some aminoacylated-tRNA species into peptidoglycan biosynthesis and/or membrane phospholipid modification. Subsequent indirect peptidoglycan cross-linkage or change in membrane permeability is often a prerequisite for high-level antibiotic resistance. In Streptomycetes, aminoacylated-tRNA species are used for antibiotic synthesis as well as antibiotic resistance. The direction of coding aminoacylated-tRNA molecules away from translation and into antibiotic resistance and synthesis pathways are discussed in this review.

  15. Modulation of Drug Resistance in Staphylococcus aureus with Coumarin Derivatives

    Directory of Open Access Journals (Sweden)

    Rodrigo Santos Aquino de Araújo

    2016-01-01

    Full Text Available Semisynthetic and commercial coumarins were investigated for their antibacterial and adjuvant properties with antibiotic agents against norfloxacin, erythromycin, and tetracycline resistant Staphylococcus aureus as based on efflux mechanisms. The coumarins and certain commercial antibiotics had their Minimum Inhibitory Concentrations determined by broth microdilution assay against resistant S. aureus strains which overexpress efflux pump proteins. For evaluation of the modulatory activity, the antibiotics MICs were determined in the presence of the coumarin derivatives at subinhibitory concentration. Although the coumarins did not display relevant antibacterial activity (MIC ≥ 128 µg/mL, they did modulate the antibiotics activities. Various coumarins, especially the alkylated derivatives in combination with antibiotics at subinhibitory concentrations, modulated antibiotic activity, reducing the MIC for tetracycline and norfloxacin by 2 to 8 times. Polar Surface Area (PSA studies were performed and the fact that the presence of apolar groups is an important factor for the modulatory activity of coumarins was corroborated. Docking on the Penicillin-Binding Protein from MRSA identified that 18 is a potential ligand presenting low Ebinding. The results indicate that coumarin derivatives modulated antibiotic resistance and may be used as potential antibiotic adjuvants, acting by bacterial efflux pump inhibition in S. aureus.

  16. New epidemiology of Staphylococcus aureus infection in Asia.

    Science.gov (United States)

    Chen, C-J; Huang, Y-C

    2014-07-01

    Not only is Asia the most populous region in the world, but inappropriate therapy, including self-medication with over-the-counter antimicrobial agents, is a common response to infectious diseases. The high antibiotic selective pressure among the overcrowded inhabitants creates an environment that is suitable for the rapid development and efficient spread of numerous multidrug-resistant pathogens. Indeed, Asia is among the regions with the highest prevalence rates of healthcare-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) and community-associated methicillin-resistant S. aureus (CA-MRSA) in the world. Most hospitals in Asia are endemic for multidrug-resistant methicillin-resistant S. aureus (MRSA), with an estimated proportion from 28% (in Hong Kong and Indonesia) to >70% (in Korea) among all clinical S. aureus isolates in the early 2010s. Isolates with reduced susceptibility or a high level of resistance to glycopeptides have also been increasingly identified in the past few years. In contrast, the proportion of MRSA among community-associated S. aureus infections in Asian countries varies markedly, from 35%. Two pandemic HA-MRSA clones, namely multilocus sequence type (ST) 239 and ST5, are disseminated internationally in Asia, whereas the molecular epidemiology of CA-MRSA in Asia is characterized by clonal heterogeneity, similar to that in Europe. In this review, the epidemiology of S. aureus in both healthcare facilities and communities in Asia is addressed, with an emphasis on the prevalence, clonal structure and antibiotic resistant profiles of the MRSA strains. The novel MRSA strains from livestock animals have been considered to constitute a public health threat in western countries. The emerging livestock-associated MRSA strains in Asia are also included in this review.

  17. Immunogenicity of toxins during Staphylococcus aureus infection

    NARCIS (Netherlands)

    N.J. Verkaik (Nelianne); O. Dauwalder (Olivier); K. Antri (Kenza); I. Boubekri (Ilhem); C.P. de Vogel (Corné); C. Badiou (Cédric); M. Bes (Michèle); F. Vandenesch (François); M. Tazir (Mohammed); H. Hooijkaas (Herbert); H.A. Verbrugh (Henri); A.F. van Belkum (Alex); J. Etienne (Jerome); G. Lina (Gérard); N. Ramdani-Bouguessa (Nadjia); W.J.B. van Wamel (Willem)

    2010-01-01

    textabstractAB - BACKGROUND: Toxins are important Staphylococcus aureus virulence factors, but little is known about their immunogenicity during infection. Here, additional insight is generated. METHODS: Serum samples from 206 S. aureus-infected patients and 201 hospital-admitted control subjects we

  18. Testing the efficacy of a molecular surveillance network: methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREF) genotypes in six hospitals in the metropolitan New York City area. The BARG Initiative Pilot Study Group. Bacterial Antibiotic Resistance Group.

    Science.gov (United States)

    de Lencastre, H; Severina, E P; Roberts, R B; Kreiswirth, B N; Tomasz, A

    1996-01-01

    Molecular fingerprinting techniques are rapidly becoming indispensable tools for hospital epidemiology. On the other hand, the relative complexity and unfamiliarity of these techniques to most hospital diagnostic laboratories limit their usefulness. In an attempt to provide a solution for this dilemma, we tested the feasibility and efficacy of a cooperative venture in which molecular typing of isolates recovered from patients in six hospitals was performed at two microbiology research laboratories with expertise in these techniques. In a small preliminary study, 30 methicillin-resistant Staphylococcus aureus (MRSA) and 30 vancomycin-resistant Enterococcus faecium (VREF) isolates were collected over a 3-week period from six hospitals in the metropolitan New York area and transported to the Laboratory of Microbiology at The Rockefeller University during the summer months of 1994. Nineteen of the 27 confirmed MRSA isolates were closely related strains carrying the same mecA and the same Tn554 polymorphs in a pulsed-field gel electrophoresis (PFGE) background represented by closely related subtypes of a single pattern, indicating the wide distribution of this MRSA clone among the participating hospitals. Typing of the same 27 MRSA isolates was also performed at the Tuberculosis Center of the Public Health Research Institute and identical results were obtained. The 29 confirmed VREF isolates were highly heterogeneous and belonged to as many as 23 distinct clonal types as defined by PFGE patterns and probing with vanA. Characterization of the 60 isolates by these methods was completed in one month of full-time effort by a single experienced laboratory assistant guided by a doctoral-level expert in molecular fingerprinting techniques. The collection of samples for both MRSA and VREF was not intended to address epidemiological questions but to determine the feasibility of a multicenter study. On the basis of our preliminary findings we are encouraged that a larger

  19. Carotenoid Formation by Staphylococcus aureus

    Science.gov (United States)

    Hammond, Ray K.; White, David C.

    1970-01-01

    The carotenoid pigments of Staphylococcus aureus U-71 were identified as phytoene; ζ-carotene; δ-carotene; phytofluenol; a phytofluenol-like carotenoid, rubixanthin; and three rubixanthin-like carotenoids after extraction, saponification, chromatographic separation, and determination of their absorption spectra. There was no evidence of carotenoid esters or glycoside ethers in the extract before saponification. During the aerobic growth cycle the total carotenoids increased from 45 to 1,000 nmoles per g (dry weight), with the greatest increases in the polar, hydroxylated carotenoids. During the anaerobic growth cycle, the total carotenoids increased from 20 nmoles per g (dry weight) to 80 nmoles per g (dry weight), and only traces of the polar carotenoids were formed. Light had no effect on carotenoid synthesis. About 0.14% of the mevalonate-2-14C added to the culture was incorporated into the carotenoids during each bacterial doubling. The total carotenoids did not lose radioactivity when grown in the absence of 14C for 2.5 bacterial doublings. The total carotenoids did not lose radioactivity when grown in the absence of 14C for 2.5 bacterial doublings. The incorporation and turnover of 14C indicated the carotenes were sequentially desaturated and hydroxylated to form the polar carotenoids. PMID:5423369

  20. [Antibiotic resistance and biofilm formation in Staphylococcus saprophyticus strains isolated from urine].

    Science.gov (United States)

    Cernohorská, L; Votava, M

    2010-04-01

    Eighty-seven Staphylococcus saprophyticus strains isolated from urine of 87 patients with cystitis were examined in 2005-2009. All strains were tested for resistance to vancomycin, nitrofurantoin, doxycycline, oxacillin, amoxicillin/clavulanate, cefoxitin and sulfamethoxazole/trimethoprim and for biofilm formation by a modified Christensen method. None of the tested strains of S. saprophyticus showed resistance to vancomycin, while 2 strains (2.3 %) were resistant to nitrofurantoin, 9 (10.3%) to doxycycline, 20 (23.0 %) to oxacillin, 6 (6.9%) to amoxicillin/clavulanate, 6 (6.9%) to cefoxitin and 1 (1.1%) to sulfamethoxazole/trimethoprim. S. saprophyticus was detected as the causative agent of cystitis in 0.4 % of 20,375 culture positive urine samples analyzed in our laboratory between 2005 and 2009. Most 67 (77.0%) S. saprophyticus strains were recovered from women, particularly from young women. Biofilm formation was detected in 16 (18.4 %) out of 87 S. saprophyticus strains.

  1. 9 CFR 113.115 - Staphylococcus Aureus Bacterin-Toxoid.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Staphylococcus Aureus Bacterin-Toxoid... REQUIREMENTS Inactivated Bacterial Products § 113.115 Staphylococcus Aureus Bacterin-Toxoid. Staphylococcus... Staphylococcus aureus which has been inactivated and is nontoxic. Each serial of biological product...

  2. Assessing Antibiotic Resistance of Staphyloccocus: Students Use Their Own Microbial Flora To Explore Antibiotic Resistance.

    Science.gov (United States)

    Omoto, Charlotte K.; Malm, Kirstin

    2003-01-01

    Describes a microbiology laboratory experiment in which students test their own microbial flora of Staphylococcus for antibiotic resistance. Provides directions on how to conduct the experiment. (YDS)

  3. Aminoglycoside inhibition of Staphylococcus aureus biofilm formation is nutrient dependent.

    Science.gov (United States)

    Henry-Stanley, Michelle J; Hess, Donavon J; Wells, Carol L

    2014-06-01

    Biofilms represent microbial communities, encased in a self-produced matrix or extracellular polymeric substance. Microbial biofilms are likely responsible for a large proportion of clinically significant infections and the multicellular nature of biofilm existence has been repeatedly associated with antibiotic resistance. Classical in vitro antibiotic-susceptibility testing utilizes artificial growth media and planktonic microbes, but this method may not account for the variability inherent in environments subject to biofilm growth in vivo. Experiments were designed to test the hypothesis that nutrient concentration can modulate the antibiotic susceptibility of Staphylococcus aureus biofilms. Developing S. aureus biofilms initiated on surgical sutures, and in selected experiments planktonic cultures, were incubated for 16 h in 66 % tryptic soy broth, 0.2 % glucose (1× TSBg), supplemented with bactericidal concentrations of gentamicin, streptomycin, ampicillin or vancomycin. In parallel experiments, antibiotics were added to growth medium diluted one-third (1/3× TSBg) or concentrated threefold (3× TSBg). Following incubation, viable bacteria were enumerated from planktonic cultures or suture sonicates, and biofilm biomass was assayed using spectrophotometry. Interestingly, bactericidal concentrations of gentamicin (5 µg gentamicin ml(-1)) and streptomycin (32 µg streptomycin ml(-1)) inhibited biofilm formation in samples incubated in 1/3× or 1× TSBg, but not in samples incubated in 3× TSBg. The nutrient dependence of aminoglycoside susceptibility is not only associated with biofilm formation, as planktonic cultures incubated in 3× TSBg in the presence of gentamicin also showed antibiotic resistance. These findings appeared specific for aminoglycosides because biofilm formation was inhibited in all three growth media supplemented with bactericidal concentrations of the cell wall-active antibiotics, ampicillin and vancomycin. Additional experiments

  4. ω-Hydroxyemodin Limits Staphylococcus aureus Quorum Sensing-Mediated Pathogenesis and Inflammation

    Science.gov (United States)

    Daly, Seth M.; Elmore, Bradley O.; Kavanaugh, Jeffrey S.; Triplett, Kathleen D.; Figueroa, Mario; Raja, Huzefa A.; El-Elimat, Tamam; Crosby, Heidi A.; Femling, Jon K.; Cech, Nadja B.; Horswill, Alexander R.; Oberlies, Nicholas H.

    2015-01-01

    Antibiotic-resistant pathogens are a global health threat. Small molecules that inhibit bacterial virulence have been suggested as alternatives or adjuncts to conventional antibiotics, as they may limit pathogenesis and increase bacterial susceptibility to host killing. Staphylococcus aureus is a major cause of invasive skin and soft tissue infections (SSTIs) in both the hospital and community settings, and it is also becoming increasingly antibiotic resistant. Quorum sensing (QS) mediated by the accessory gene regulator (agr) controls virulence factor production essential for causing SSTIs. We recently identified ω-hydroxyemodin (OHM), a polyhydroxyanthraquinone isolated from solid-phase cultures of Penicillium restrictum, as a suppressor of QS and a compound sought for the further characterization of the mechanism of action. At concentrations that are nontoxic to eukaryotic cells and subinhibitory to bacterial growth, OHM prevented agr signaling by all four S. aureus agr alleles. OHM inhibited QS by direct binding to AgrA, the response regulator encoded by the agr operon, preventing the interaction of AgrA with the agr P2 promoter. Importantly, OHM was efficacious in a mouse model of S. aureus SSTI. Decreased dermonecrosis with OHM treatment was associated with enhanced bacterial clearance and reductions in inflammatory cytokine transcription and expression at the site of infection. Furthermore, OHM treatment enhanced the immune cell killing of S. aureus in vitro in an agr-dependent manner. These data suggest that bacterial disarmament through the suppression of S. aureus QS may bolster the host innate immune response and limit inflammation. PMID:25645827

  5. Genetic effects of an air discharge plasma on Staphylococcus aureus at the gene transcription level

    Science.gov (United States)

    Xu, Zimu; Wei, Jun; Shen, Jie; Liu, Yuan; Ma, Ronghua; Zhang, Zelong; Qian, Shulou; Ma, Jie; Lan, Yan; Zhang, Hao; Zhao, Ying; Xia, Weidong; Sun, Qiang; Cheng, Cheng; Chu, Paul K.

    2015-05-01

    The dynamics of gene expression regulation (at transcription level) in Staphylococcus aureus after different doses of atmospheric-pressure room-temperature air plasma treatments are investigated by monitoring the quantitative real-time polymerase chain reaction. The plasma treatment influences the transcription of genes which are associated with several important bio-molecular processes related to the environmental stress resistance of the bacteria, including oxidative stress response, biofilm formation, antibiotics resistance, and DNA damage protection/repair. The reactive species generated by the plasma discharge in the gas phase and/or induced in the liquid phase may account for these gene expression changes.

  6. Evasion of Neutrophil Killing by Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Will A. McGuinness

    2016-03-01

    Full Text Available Staphylococcus aureus causes many types of infections, ranging from self-resolving skin infections to severe or fatal pneumonia. Human innate immune cells, called polymorphonuclear leukocytes (PMNs or neutrophils, are essential for defense against S. aureus infections. Neutrophils are the most prominent cell type of the innate immune system and are capable of producing non-specific antimicrobial molecules that are effective at eliminating bacteria. Although significant progress has been made over the past few decades, our knowledge of S. aureus-host innate immune system interactions is incomplete. Most notably, S. aureus has the capacity to produce numerous molecules that are directed to protect the bacterium from neutrophils. Here we review in brief the role played by neutrophils in defense against S. aureus infection, and correspondingly, highlight selected S. aureus molecules that target key neutrophil functions.

  7. Bacterial viruses enable their host to acquire antibiotic resistance genes from neighbouring cells

    DEFF Research Database (Denmark)

    Haaber, Jakob; Leisner, Jørgen J; Cohn, Marianne T;

    2016-01-01

    Prophages are quiescent viruses located in the chromosomes of bacteria. In the human pathogen, Staphylococcus aureus, prophages are omnipresent and are believed to be responsible for the spread of some antibiotic resistance genes. Here we demonstrate that release of phages from a subpopulation of S...

  8. Bacterial viruses enable their host to acquire antibiotic resistance genes from neighbouring cells

    DEFF Research Database (Denmark)

    Haaber, Jakob Krause; Leisner, Jørgen; Cohn, Marianne Thorup;

    2016-01-01

    Prophages are quiescent viruses located in the chromosomes of bacteria. In the human pathogen, Staphylococcus aureus, prophages are omnipresent and are believed to be responsible for the spread of some antibiotic resistance genes. Here we demonstrate that release of phages from a subpopulation of...

  9. Stress Responses in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Frees, Dorte; Ingmer, Hanne

    2016-01-01

    stress responses allowing it to sense and adapt to its very different niches. The stress responses often involve dramatic cellular reprogramming, and the technological advances provided by the access to whole genome sequences have let to an unprecedented insight into the global reorganization of gene...... and protein expression following stress-exposure. Characterization of global gene responses has been very helpful both in identifying regulators sensing specific environmental stress signals and overlaps between different stress responses. In this chapter we review the recent progress in our understanding...... of the specific and general S. aureusstress responses, with a special emphasis on how stress responses contribute to virulence and antibiotic resistance in this important human pathogen....

  10. Etudes structurales du ribosome de Staphylococcus aureus

    OpenAIRE

    Khusainov, Iskander

    2015-01-01

    The ribosome is a large cellular machinery that performs the protein synthesis in every living cell. Therefore, the ribosome is one of the major targets of naturally produced antibiotics, which can kill bacterial cells by blocking protein synthesis. However, some bacteria are resistant to these antibiotics due to small modifications of their ribosomes. Among them, Staphylococcus aureus (S. aureus) is a severe pathogen that causes numerous infections in humans. The crystal structures of comple...

  11. The Recombinant Bacteriophage Endolysin HY-133 Exhibits In Vitro Activity against Different African Clonal Lineages of the Staphylococcus aureus Complex, Including Staphylococcus schweitzeri.

    Science.gov (United States)

    Idelevich, Evgeny A; Schaumburg, Frieder; Knaack, Dennis; Scherzinger, Anna S; Mutter, Wolfgang; Peters, Georg; Peschel, Andreas; Becker, Karsten

    2016-04-01

    HY-133 is a recombinant bacteriophage endolysin with bactericidal activity againstStaphylococcus aureus Here, HY-133 showedin vitroactivity against major African methicillin-susceptible and methicillin-resistantS. aureuslineages and ceftaroline/ceftobiprole- and borderline oxacillin-resistant isolates. HY-133 was also active againstStaphylococcus schweitzeri, a recently described species of theS. aureuscomplex. The activity of HY-133 on the tested isolates (MIC50, 0.25 μg/ml; MIC90, 0.5 μg/ml; range, 0.125 to 0.5 μg/ml) was independent of the species and strain background or antibiotic resistance.

  12. Antibiotic Resistance

    DEFF Research Database (Denmark)

    Hansen, Malene Plejdrup; Hoffmann, Tammy C; McCullough, Amanda R

    2015-01-01

    Numerous opportunities are available in primary care for alleviating the crisis of increasing antibiotic resistance. Preventing patients from developing an acute respiratory infection (ARI) will obviate any need for antibiotic use downstream. Hygiene measures such as physical barriers and hand...... wrong. Shared decision making might be a solution, as it enables clinician and patient to participate jointly in making a health decision, having discussed the options together with the evidence for their harms as well as benefits. Furthermore, GPs' diagnostic uncertainty - often leading...... will greatly improve the use of antibiotics for ARIs. However, used in concert, combinations are likely to enable clinicians and health care systems to implement the strategies that will reduce antimicrobial resistance in the future....

  13. Antibiotic Resistance

    DEFF Research Database (Denmark)

    Munck, Christian

    morbidity and mortality as well as an increase in the cost of treatment. Understanding how bacteria respond to antibiotic exposure gives the foundations for a rational approach to counteract antimicrobial resistance. In the work presented in this thesis, I explore the two fundamental sources...... of antimicrobial resistance: (1) adaptive mutations and (2) horizontal acquisition of resistance genes from antibiotic gene reservoirs. By studying the geno- and phenotypic changes of E. coli in response to single and drug-pair exposures, I uncover the evolutionary trajectories leading to adaptive resistance. I...... to rationally design drug combinations that limit the evolution of antibiotic resistance due to counteracting evolutionary trajectories. My results highlight that an in-depth knowledge about the genetic responses to the individual antimicrobial compounds enables the prediction of responses to drug combinations...

  14. Triclosan promotes Staphylococcus aureus nasal colonization.

    Science.gov (United States)

    Syed, Adnan K; Ghosh, Sudeshna; Love, Nancy G; Boles, Blaise R

    2014-04-08

    The biocide triclosan is used in many personal care products, including toothpastes, soaps, clothing, and medical equipment. Consequently, it is present as a contaminant in the environment and has been detected in some human fluids, including serum, urine, and milk. Staphylococcus aureus is an opportunistic pathogen that colonizes the noses and throats of approximately 30% of the population. Colonization with S. aureus is known to be a risk factor for several types of infection. Here we demonstrate that triclosan is commonly found in the nasal secretions of healthy adults and the presence of triclosan trends positively with nasal colonization by S. aureus. We demonstrate that triclosan can promote the binding of S. aureus to host proteins such as collagen, fibronectin, and keratin, as well as inanimate surfaces such as plastic and glass. Lastly, triclosan-exposed rats are more susceptible to nasal colonization with S. aureus. These data reveal a novel factor that influences the ability of S. aureus to bind surfaces and alters S. aureus nasal colonization. IMPORTANCE Triclosan has been used as a biocide for over 40 years, but the broader effects that it has on the human microbiome have not been investigated. We demonstrate that triclosan is present in nasal secretions of a large portion of a test population and its presence correlates with Staphylococcus aureus nasal colonization. Triclosan also promotes the binding of S. aureus to human proteins and increases the susceptibility of rats to nasal colonization by S. aureus. These findings are significant because S. aureus colonization is a known risk factor for the development of several types of infections. Our data demonstrate the unintended consequences of unregulated triclosan use and contribute to the growing body of research demonstrating inadvertent effects of triclosan on the environment and human health.

  15. Sn doping induced enhancement in the activity of ZnO nanostructures against antibiotic resistant S. aureus bacteria

    Directory of Open Access Journals (Sweden)

    Jan T

    2013-09-01

    Full Text Available Tariq Jan,1 Javed Iqbal,1 Muhammad Ismail,2 M Zakaullah,3 Sajjad Haider Naqvi,4 Noor Badshah51Laboratory of Nanoscience and Technology, Department of Physics, International Islamic University, Islamabad, Pakistan; 2Institute of Biomedical and Genetic Engineering, Islamabad, Pakistan; 3Department of Physics, Quaid-i-Azam University, Islamabad, Pakistan; 4Department of Biochemistry, University of Karachi, Karachi, Pakistan; 5Department of Basic Science, University of Engineering and Technology, Peshawar, PakistanAbstract: Highly ionic metal oxide nanostructures are attractive, not only for their physiochemical properties but also for antibacterial activity. Zinc oxide (ZnO nanostructures are known to have inhibitory activity against many pathogens but very little is known about doping effects on it. The antibacterial activity of undoped ZnO and tin (Sn doped ZnO nanostructures synthesized by a simple, versatile, and wet chemical technique have been investigated against Escherichia coli, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa bacterial strains. It has been interestingly observed that Sn doping enhanced the inhibitory activity of ZnO against S. aureus more efficiently than the other two bacterial strains. From cytotoxicity and reactive oxygen species (ROS production studies it is found that Sn doping concentration in ZnO does not alter the cytotoxicity and ROS production very much. It has also been observed that undoped and Sn doped ZnO nanostructures are biosafe and biocompatible materials towards SH-SY5Y Cells. The observed behavior of ZnO nanostructures with Sn doping is a new way to prevent bacterial infections of S. aureus, especially on skin, when using these nanostructures in creams or lotions in addition to their sunscreen property as an ultraviolet filter. Structural investigations have confirmed the formation of a single phase wurtzite structure of ZnO. The morphology of ZnO nanostructures is found to vary

  16. Characterisation of Staphylococcus aureus bacteraemia at Tygerberg hospital

    NARCIS (Netherlands)

    Orth, H.; Dreyer, Z.S.; Makgotlho, E.; Oosthuysen, W.; Sinha, B.; Wasserman, E.

    2013-01-01

    To elucidate the local epidemiology of Staphylococcus aureus bacteraemia, we characterised blood culture isolates using molecular methods and prospectively collected clinical data to determine the occurrence of community-acquired, methicillinresistant S. aureus (MRSA). Consecutive S. aureus blood cu

  17. The complex biology and contribution of Staphylococcus aureus in atopic dermatitis, current and future therapies.

    Science.gov (United States)

    Hepburn, L; Hijnen, D J; Sellman, B R; Mustelin, T; Sleeman, M A; May, R D; Strickland, I

    2016-10-25

    Atopic dermatitis (AD) is a complex, chronic inflammatory skin disorder affecting more than 10% of UK children and is a major cause of occupation-related disability. A subset of patients, particularly those with severe AD, are persistently colonised with Staphylococcus aureus (S. aureus) and exacerbation of disease is commonly associated with this bacterium by virtue of increased inflammation and allergic sensitisation, aggravated by skin barrier defects. Understanding the complex biology of S. aureus is an important factor when developing new drugs to combat infection. S. aureus generates exoproteins that enable invasion and dissemination within the host skin but can also damage the skin and activate the host immune system. Antibiotics are often used by dermatologists to aid clearance of S. aureus; however, these are becoming less effective and chronic usage discouraged with the emergence of multiple antibiotic-resistant strains. New ways to target S. aureus using monoclonal antibodies and vaccines are now being developed. This review will attempt to evaluate the key biology of S. aureus, current treatment of S. aureus infections in atopic dermatitis and recent advances in developing new anti-S. aureus therapies that have potential in severe AD. This article is protected by copyright. All rights reserved.

  18. Structure of the 70S ribosome from human pathogen Staphylococcus aureus.

    Science.gov (United States)

    Khusainov, Iskander; Vicens, Quentin; Bochler, Anthony; Grosse, François; Myasnikov, Alexander; Ménétret, Jean-François; Chicher, Johana; Marzi, Stefano; Romby, Pascale; Yusupova, Gulnara; Yusupov, Marat; Hashem, Yaser

    2016-12-01

    Comparative structural studies of ribosomes from various organisms keep offering exciting insights on how species-specific or environment-related structural features of ribosomes may impact translation specificity and its regulation. Although the importance of such features may be less obvious within more closely related organisms, their existence could account for vital yet species-specific mechanisms of translation regulation that would involve stalling, cell survival and antibiotic resistance. Here, we present the first full 70S ribosome structure from Staphylococcus aureus, a Gram-positive pathogenic bacterium, solved by cryo-electron microscopy. Comparative analysis with other known bacterial ribosomes pinpoints several unique features specific to S. aureus around a conserved core, at both the protein and the RNA levels. Our work provides the structural basis for the many studies aiming at understanding translation regulation in S. aureus and for designing drugs against this often multi-resistant pathogen.

  19. Identification of potential anti-infectives against Staphylococcus aureus using a Caenorhabditis elegans infection model

    Science.gov (United States)

    Kong, Cin; Rahman, Noorsaadah Abd; Nathan, Sheila

    2014-09-01

    The alarming increase of antibiotic-resistant Staphylococcus aureus and a delay in antibiotics development point to the need for novel therapeutic approaches to combat infection. To discover novel anti-infective agents, we screened a number of synthetic compounds comprising mainly of chalcone derivatives to explore their potential in promoting the survival of the nematode Caenorhabditis elegans upon infection by S. aureus. Screening of seven chalcone derivatives using both agar- and liquid-based assays revealed three positive hits that significantly prolonged the survival of S. aureus-infected nematodes. All the hits did not interfere with bacterial growth in vitro, proposing that the three compounds identified most probably act through mechanisms distinct from conventional antibiotics that target bacterial replication.

  20. Synergism between Medihoney and rifampicin against methicillin-resistant Staphylococcus aureus (MRSA.

    Directory of Open Access Journals (Sweden)

    Patrick Müller

    Full Text Available Skin and chronic wound infections caused by highly antibiotic resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA are an increasing and urgent health problem worldwide, particularly with sharp increases in obesity and diabetes. New Zealand manuka honey has potent broad-spectrum antimicrobial activity, has been shown to inhibit the growth of MRSA strains, and bacteria resistant to this honey have not been obtainable in the laboratory. Combinational treatment of chronic wounds with manuka honey and common antibiotics may offer a wide range of advantages including synergistic enhancement of the antibacterial activity, reduction of the effective dose of the antibiotic, and reduction of the risk of antibiotic resistance. The aim of this study was to investigate the effect of Medihoney in combination with the widely used antibiotic rifampicin on S. aureus. Using checkerboard microdilution assays, time-kill curve experiments and agar diffusion assays, we show a synergism between Medihoney and rifampicin against MRSA and clinical isolates of S. aureus. Furthermore, the Medihoney/rifampicin combination stopped the appearance of rifampicin-resistant S. aureus in vitro. Methylglyoxal (MGO, believed to be the major antibacterial compound in manuka honey, did not act synergistically with rifampicin and is therefore not the sole factor responsible for the synergistic effect of manuka honey with rifampicin. Our findings support the idea that a combination of honey and antibiotics may be an effective new antimicrobial therapy for chronic wound infections.

  1. Epidemiology of Staphylococcus aureus in Italy: First nationwide survey, 2012.

    Science.gov (United States)

    Campanile, Floriana; Bongiorno, Dafne; Perez, Marianna; Mongelli, Gino; Sessa, Laura; Benvenuto, Sabrina; Gona, Floriana; Varaldo, Pietro E; Stefani, Stefania

    2015-12-01

    A 3-month epidemiological study to determine the prevalence and antibiotic resistance of Staphylococcus aureus nosocomial infections was performed in 52 centres throughout Italy in 2012. A total of 21,873 pathogens were analysed. The prevalence of S. aureus among all nosocomial pathogens isolated in that period was 11.6% (n=2541), whilst the prevalence of methicillin-resistant S. aureus (MRSA) among the S. aureus was 35.8% (n=910). All tested antimicrobials demonstrated ≥92.2% susceptibility against methicillin-susceptible S. aureus, with the exception of clindamycin (89.7%) and erythromycin (84.2%). Among MRSA, percentages of resistance ranged from 12.6% to >39% for tetracycline, rifampicin, clindamycin and gentamicin; higher percentages were found for erythromycin (65.4%) and fluoroquinolones (72.3-85.8%). Overall, the glycopeptide minimum inhibitory concentration (MIC) distribution showed that 58.3% of strains possessed MICs of 1-2mg/L and few strains were linezolid- or daptomycin-resistant. Molecular characterisation was performed on 102 MRSA selected from Northern, Central and Southern regions. Five major clones were found: Italian/ST228-I (t001-t023-t041-t1686-t3217), 33.3%; USA500/ST8-IV (t008), 17.6%; E-MRSA15/ST22-IVh (t020-t025-t032-t223), 16.7%; USA100/ST5-II (t002-t653-t1349-t2164-t3217-t388), 14.7%; and Brazilian/ST239/241-III (t030-t037), 3.9%. Five PVL-positive CA-MRSA isolates, belonging to USA300 and minor clones, were also identified. In conclusion, this first nationwide surveillance study showed that in Italy, S. aureus infections accounted for 11.6% of all nosocomial infections; MRSA accounted for approximately one-third of the S. aureus isolates and these were multidrug-resistant organisms. Five major MRSA epidemic clones were observed and were inter-regionally distributed, with ST228-SCCmecI becoming predominant.

  2. Bacterial viruses enable their host to acquire antibiotic resistance genes from neighbouring cells

    DEFF Research Database (Denmark)

    Haaber, Jakob Krause; Leisner, Jørgen; Cohn, Marianne Thorup

    2016-01-01

    Prophages are quiescent viruses located in the chromosomes of bacteria. In the human pathogen, Staphylococcus aureus, prophages are omnipresent and are believed to be responsible for the spread of some antibiotic resistance genes. Here we demonstrate that release of phages from a subpopulation of S....... aureus cells enables the intact, prophage-containing population to acquire beneficial genes from competing, phage-susceptible strains present in the same environment. Phage infection kills competitor cells and bits of their DNA are occasionally captured in viral transducing particles. Return...... of such particles to the prophage-containing population can drive the transfer of genes encoding potentially useful traits such as antibiotic resistance. This process, which can be viewed as ‘auto-transduction’, allows S. aureus to efficiently acquire antibiotic resistance both in vitro and in an in vivo virulence...

  3. Meningitis causada por staphylococcus aureus catalasa negativa

    OpenAIRE

    Álvarez Moreno, Carlos Arturo; Arroyo A., Claudia Patricia; Rodríguez, Elizabeth; Martínez R., Luz Marina; Quevedo S., Ruth

    2011-01-01

    En un paciente con cáncer se aisló del liquido cefaloraquideo y ascitico un coco gram positivo coagulasa positivo. El germen aislado mostró las características típicas de un Staphylococcus aureus, a excepción de la actividad de la catalasa, la cual no pudo ser encontrada.

  4. Staphylococcus aureus spa type t437

    DEFF Research Database (Denmark)

    Glasner, C; Pluister, G; Westh, H;

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) belonging to the multilocus sequence type clonal complex 59 (MLST CC59) is the predominant community-associated MRSA clone in Asia. This clone, which is primarily linked with the spa type t437, has so far only been reported in low numbers among...

  5. Meticillin-resistant Staphylococcus aureus (MRSA)

    DEFF Research Database (Denmark)

    Stefani, Stefania; Chung, Doo Ryeon; Lindsay, Jodi A;

    2012-01-01

    This article reviews recent findings on the global epidemiology of healthcare-acquired/associated (HA), community-acquired/associated (CA) and livestock-associated (LA) meticillin-resistant Staphylococcus aureus (MRSA) and aims to reach a consensus regarding the harmonisation of typing methods...

  6. Methicillin-resistant Staphylococcus aureus transmission

    DEFF Research Database (Denmark)

    Andersen, Leif Percival; Nielsen, Xiaohui

    2015-01-01

    INTRODUCTION: Even though methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial infections, it may often be difficult to evaluate the exact route of transmission. METHODS: In this study, we describe four cases of nosocomial transmission of MRSA in a hospital with a low...

  7. Profiling the surfacome of Staphylococcus aureus

    NARCIS (Netherlands)

    Dreisbach, Annette; Hempel, Kristina; Buist, Girbe; Hecker, Michael; Becher, Doerte; van Dijl, Jan Maarten

    2010-01-01

    Staphylococcus aureus is a widespread opportunistic pathogen that can cause a wide variety of life-threatening diseases. Especially for the colonization of human tissues and the development of invasiveness, surface-exposed proteins are of major importance. In the present studies, we optimized a prot

  8. Staphylococcus aureus resistente a la meticilina (SARM)

    Centers for Disease Control (CDC) Podcasts

    2007-10-22

    Datos importantes sobre las infecciones por SARM en Estados Unidos, en las escuelas y los entornos médicos. (Title: Methicillin-resistant Staphylococcus aureus (MRSA)Created: 10/2007).  Created: 10/22/2007 by National Center for Preparedness, Detection, and Control of Infectious Diseases.   Date Released: 11/9/2007.

  9. Methicillin-resistant Staphylococcus aureus: a new zoonotic agent?

    Science.gov (United States)

    Springer, Burkhard; Orendi, Ulrike; Much, Peter; Höger, Gerda; Ruppitsch, Werner; Krziwanek, Karina; Metz-Gercek, Sigrid; Mittermayer, Helmut

    2009-01-01

    Staphylococcus aureus is a major cause of infection in hospitals and the community. One third of the general population is colonized by the bacterium, constituting a risk factor for acquisition of infection with this pathogen. Worldwide, the increasing antibiotic resistance of S. aureus complicates treatment of infection and control measures. Soon after the introduction of methicillin, the first isolates resistant to this antibiotic were reported and named methicillin-resistant S. aureus (MRSA). During the past decade a major change in MRSA epidemiology has been observed: whereas in the past MRSA was almost exclusively regarded a hospital pathogen, the advent of community-acquired MRSA has led to infections in people without hospital-related risk factors. Recent evidence has also identified a link between colonization of livestock and MRSA carriage and infections in people who work with animals. Screening of pigs and pig farmers in the Netherlands revealed high prevalence of MRSA sequence type (ST) 398 and it has become clear that the emergence of ST398 is not just a Dutch problem, as reports on livestock colonization and human infections are appearing worldwide. In Austria, the ST398 lineage has been detected in dust samples from pig breeding facilities and in food samples. Since the first Austrian detection of this emerging lineage in 2006, 21 human isolates, partially associated with infections, have been observed. MRSA has to be regarded as a new emerging zoonotic agent and livestock may constitute a growing reservoir of the ST398 lineage. More information is needed so that control measures to reduce the impact of the emerging MRSA ST398 lineage on public health can be developed and implemented.

  10. Postoperative Staphylococcus aureus infections in Medicare beneficiaries.

    Directory of Open Access Journals (Sweden)

    Moaven Razavi

    Full Text Available Staphylococcus aureus (S. aureus infections are important because of their increasing frequency, resistance to antibiotics, and high associated rates of disabilities and deaths. We examined the incidence and correlates of S. aureus infections following 219,958 major surgical procedures in a 5% random sample of fee-for-service Medicare beneficiaries from 2004-2007. Of these surgical patients, 0.3% had S. aureus infections during the hospitalizations when index surgical procedures were performed; and 1.7% and 2.3%, respectively, were hospitalized with infections within 60 days or 180 days following admissions for index surgeries. S. aureus infections occurred within 180 days in 1.9% of patients following coronary artery bypass graft surgery, 2.3% following hip surgery, and 5.9% following gastric or esophageal surgery. Of patients first hospitalized with any major infection reported during the first 180 days after index surgery, 15% of infections were due to S. aureus, 18% to other documented organisms, and no specific organism was reported on claim forms in 67%. Patient-level predictors of S. aureus infections included transfer from skilled nursing facilities or chronic hospitals and comorbid conditions (e.g., diabetes, congestive heart failure, chronic obstructive pulmonary disease, and chronic renal disease. In a logarithmic regression, elective index admissions with S. aureus infection stayed 130% longer than comparable patients without that infection. Within 180 days of the index surgery, 23.9% of patients with S. aureus infection and 10.6% of patients without this infection had died. In a multivariate logistic regression of death within 180 days of admission for the index surgery with adjustment for demographics, co-morbidities, and other risks, S. aureus was associated with a 42% excess risk of death. Due to incomplete documentation of organisms in Medicare claims, these statistics may underestimate the magnitude of S. aureus infection

  11. Catalase-negative, methicillin-resistant Staphylococcus aureus as a cause of septicemia Staphylococcus aureus catalase-negativo resistente a meticilina como causa de septicemia

    Directory of Open Access Journals (Sweden)

    Ana Lúcia Innaco de Carvalho

    2003-01-01

    Full Text Available A catalase-negative methicillin-resistant Staphylococcus aureus (MRSA was isolated from blood, venous catheter spike and bone marrow collected from an HIV-positive man with lobar pneumonia and sepsis after ten days of hospitalization. The isolate was resistant to oxacillin (positive for penicillin-binding protein 2', ceftriaxone, clindamycin and clarithromycin, and susceptible to vancomycin. This is the first case of septicemia due to a catalase-negative S. aureus reported in Brazil, and, to our knowledge, it is the first case of catalase-negative MRSA reported in the literature. We believe that the patient acquired the S. aureus infection within the hospital environment since it was isolated ten days after hospitalization, it was isolated in a venous catheter spike, and the antibiotic resistance profile is similar to other S. aureus isolates recovered from infections in our hospital.Em um paciente HIV-positivo, com pneumonia lobar e septicemia, foi isolada, após dez dias de internação, uma cepa de Staphylococcus aureus catalase-negativa, resistente a meticilina/oxacilina (MRSA, de culturas de sangue, cateter venoso central e medula óssea. A cepa era resistente a oxacilina (PBP 2' positivo, ceftriaxona, clindamicina e claritromicina, e sensível a vancomicina. Este é o primeiro caso, reportado no Brasil, de uma septicemia por S. aureus catalase-negativo e, em nosso conhecimento, o primeiro caso de um S. aureus catalase-negativo resistente a meticilina. Nós acreditamos que o paciente tenha adquirido a infecção no ambiente hospitalar, uma vez que esta cepa foi isolada aos dez dias de internação, foi isolada em cateter venoso central e o perfil de sensibilidade aos antimicrobianos é semelhante ao dos S. aureus de infecções nosocomiais que ocorrem em nosso hospital.

  12. Clonal expansion during Staphylococcus aureus infection dynamics reveals the effect of antibiotic intervention.

    Directory of Open Access Journals (Sweden)

    Gareth McVicker

    2014-02-01

    Full Text Available To slow the inexorable rise of antibiotic resistance we must understand how drugs impact on pathogenesis and influence the selection of resistant clones. Staphylococcus aureus is an important human pathogen with populations of antibiotic-resistant bacteria in hospitals and the community. Host phagocytes play a crucial role in controlling S. aureus infection, which can lead to a population "bottleneck" whereby clonal expansion of a small fraction of the initial inoculum founds a systemic infection. Such population dynamics may have important consequences on the effect of antibiotic intervention. Low doses of antibiotics have been shown to affect in vitro growth and the generation of resistant mutants over the long term, however whether this has any in vivo relevance is unknown. In this work, the population dynamics of S. aureus pathogenesis were studied in vivo using antibiotic-resistant strains constructed in an isogenic background, coupled with systemic models of infection in both the mouse and zebrafish embryo. Murine experiments revealed unexpected and complex bacterial population kinetics arising from clonal expansion during infection in particular organs. We subsequently elucidated the effect of antibiotic intervention within the host using mixed inocula of resistant and sensitive bacteria. Sub-curative tetracycline doses support the preferential expansion of resistant microorganisms, importantly unrelated to effects on growth rate or de novo resistance acquisition. This novel phenomenon is generic, occurring with methicillin-resistant S. aureus (MRSA in the presence of β-lactams and with the unrelated human pathogen Pseudomonas aeruginosa. The selection of resistant clones at low antibiotic levels can result in a rapid increase in their prevalence under conditions that would previously not be thought to favor them. Our results have key implications for the design of effective treatment regimes to limit the spread of antimicrobial

  13. Microbial Quality and Antimicrobial Resistance of Staphylococcus aureus and Escherichia coli Isolated from Traditional Ice Cream in Hamadan City, West of Iran

    Directory of Open Access Journals (Sweden)

    Ghadimi

    2016-10-01

    Full Text Available Background Foodborne diseases are one of the most major public health concerns in the world. Ice cream flavors, especially the traditional ones, have a high potential for the transmission of the pathogenic bacteria. Objectives The aim of the current study is to investigate the microbiological status and antibiotic resistance of Escherichia coli and Staphylococcus aureus isolated from traditional ice cream. Methods A total of 114 traditional ice creams were randomly collected from retail stores in Hamadan, Iran. Samples were investigated for the total bacteria count (TBC and contamination with the coliform, Enterobacteriaceae and Salmonella as well as the prevalence and antibiotic resistance of Staphylococcus aureus and Escherichia coli. Results The count of Enterobacteriaceae (89.47%, mold and yeast (50%, coliform (40.35% and TBC (28.07% of samples was higher than Iran’s standard. Salmonella was not found in all samples. The prevalence of Staphylococcus aureus and Escherichia coli was confirmed in 50% and 37.72% of samples, respectively. Collected Escherichia coli had the highest antibiotic resistance to ampicillin 67.44%, nalidixic acid 39.53% and co-amoxyclav 37.21%. Staphylococcus aureus showed a higher antibiotic resistance to penicillin (82.46% of isolates and oxacillin (38% of isolates. Conclusions The results showed high contamination levels of traditional ice cream with spoilage and pathogenic microorganisms as well as considerable resistance of isolated Staphylococcus aureus and Escherichia coli to common antibiotics. Therefore, good hygienic practice during processing and personal hygiene should be considered to improve the quality of ice cream. In addition, it is necessary that the regulatory authorities carry out more control on the production centers of traditional ice cream.

  14. Killing of Staphylococcus aureus via Magnetic Hyperthermia Mediated by Magnetotactic Bacteria.

    Science.gov (United States)

    Chen, Changyou; Chen, Linjie; Yi, Yong; Chen, Chuanfang; Wu, Long-Fei; Song, Tao

    2016-02-12

    Staphylococcus aureus is a common hospital and household pathogen. Given the emergence of antibiotic-resistant derivatives of this pathogen resulting from the use of antibiotics as general treatment, development of alternative therapeutic strategies is urgently needed. Here, we assess the feasibility of killing S. aureus cells in vitro and in vivo through magnetic hyperthermia mediated by magnetotactic bacteria that possess magnetic nanocrystals and demonstrate magnetically steered swimming. The S. aureus suspension was added to magnetotactic MO-1 bacteria either directly or after coating with anti-MO-1 polyclonal antibodies. The suspensions were then subjected to an alternating magnetic field (AMF) for 1 h. S. aureus viability was subsequently assessed through conventional plate counting and flow cytometry. We found that approximately 30% of the S. aureus cells mixed with uncoated MO-1 cells were killed after AMF treatment. Moreover, attachment between the magnetotactic bacteria and S. aureus increased the killing efficiency of hyperthermia to more than 50%. Using mouse models, we demonstrated that magnetic hyperthermia mediated by antibody-coated magnetotactic MO-1 bacteria significantly improved wound healing. These results collectively demonstrated the effective eradication of S. aureus both in vitro and in vivo, indicating the potential of magnetotactic bacterium-mediated magnetic hyperthermia as a treatment for S. aureus-induced skin or wound infections.

  15. Epidemiology of antibiotic resistance in Burkina Faso

    Institute of Scientific and Technical Information of China (English)

    Simpore J; Zeba B; Karou D; Ilboudo D; Pignatelli S; Nacoulma OG; Musumeci S

    2008-01-01

    Burkina Faso (West Africa)is a tropical country with a high incidence of infectious diseases.The uncontrolled use of antibiotics against bacterial pathogens has given rise to the emergence of antibiotic resistance in this country.The aims of this study were.i)to determine the prevalences of the most important pathogenic bacteri-a,isolated in the town of Ouagadougou.ii)to identify the bacterial species which have acquired resistance as a result of antibiotic selection.iii)to compare antibiotic-resistances ofEscherichia coli isolated from stool cul-ture in the present study,with results obtained in 2002 from strains collected in the same structure in Burkina Faso.iv)to determine the trend of antibiotic resistance in Burkina Faso in order to give local advice on the most appropriate empiric antibiotic therapy.Six thousand two hundred and sixty four samples of blood,stools, urine,sputum,pus and vaginal secretion were collected and analyzed in Saint Camille Medical Center (SC-MC)laboratory from May 2001 to May 2006.Out of the 6264 samples tested no pathogen was identified in 1583 (25.31%),whilst 4681 (74.73%)were positive,with the incidence of the microrganisms isolated be-ing as follows:Escherichia coli 1291 (27.6%),Staphylococcus aureus 922 (19.7%),Salmonella spp 561 (12.0%),Streptococcus spp 499 (10.7%),Klebsiella spp 359 (7.7%),Shigella spp (6.3%),Acineto-bacter spp 266 (5.7%)and others 783 (16.7%).Among the isolated pathogens,the highest resistance was found to Amoxycillin:Proteus spp 95.6%,Escherichia coli 78.2%,Salmonella spp 62.2%,Shigella spp 73. 4% and Klebsiella spp 89.9%,followed by resistance to Ampicillin and cotrimoxazole.Comparing the preva-lence of antibiotic resistance of Escherichia coli from stool cultures isolated during 1999-2000 to that of 2001-2006,a significant reduction was found,which could be due to the improved use of antibiotics in recent years. The reduced antibiotic-resistance observed in pathogens isolated in Burkina Faso during this

  16. In vivo killing of Staphylococcus aureus using a light-activated antimicrobial agent

    Science.gov (United States)

    2009-01-01

    Background The widespread problem of antibiotic resistance in pathogens such as Staphylococcus aureus has prompted the search for new antimicrobial approaches. In this study we report for the first time the use of a light-activated antimicrobial agent, methylene blue, to kill an epidemic methicillin-resistant Staphylococcus aureus (EMRSA-16) strain in two mouse wound models. Results Following irradiation of wounds with 360 J/cm2 of laser light (670 nm) in the presence of 100 μg/ml of methylene blue, a 25-fold reduction in the number of viable EMRSA was seen. This was independent of the increase in temperature of the wounds associated with the treatment. Histological examination of the wounds revealed no difference between the photodynamic therapy (PDT)-treated wounds and the untreated wounds, all of which showed the same degree of inflammatory infiltration at 24 hours. Conclusion The results of this study demonstrate that PDT is effective at reducing the total number of viable EMRSA in a wound. This approach has promise as a means of treating wound infections caused by antibiotic-resistant microbes as well as for the elimination of such organisms from carriage sites. PMID:19193212

  17. In vivo killing of Staphylococcus aureus using a light-activated antimicrobial agent

    Directory of Open Access Journals (Sweden)

    Bennett Jon

    2009-02-01

    Full Text Available Abstract Background The widespread problem of antibiotic resistance in pathogens such as Staphylococcus aureus has prompted the search for new antimicrobial approaches. In this study we report for the first time the use of a light-activated antimicrobial agent, methylene blue, to kill an epidemic methicillin-resistant Staphylococcus aureus (EMRSA-16 strain in two mouse wound models. Results Following irradiation of wounds with 360 J/cm2 of laser light (670 nm in the presence of 100 μg/ml of methylene blue, a 25-fold reduction in the number of viable EMRSA was seen. This was independent of the increase in temperature of the wounds associated with the treatment. Histological examination of the wounds revealed no difference between the photodynamic therapy (PDT-treated wounds and the untreated wounds, all of which showed the same degree of inflammatory infiltration at 24 hours. Conclusion The results of this study demonstrate that PDT is effective at reducing the total number of viable EMRSA in a wound. This approach has promise as a means of treating wound infections caused by antibiotic-resistant microbes as well as for the elimination of such organisms from carriage sites.

  18. In Vitro Antibacterial and Antibiotic Resistance Modifying Effect of Bioactive Plant Extracts on Methicillin-Resistant Staphylococcus epidermidis

    OpenAIRE

    Romana Chovanová; Mária Mikulášová; Štefánia Vaverková

    2013-01-01

    The crude extracts of plants from Asteraceae and Lamiaceae family and essential oils from Salvia officinalis and Salvia sclarea were studied for their antibacterial as well as antibiotic resistance modifying activity. Using disc diffusion and broth microdilution assays we determined higher antibacterial effect of three Salvia spp. and by evaluating the leakage of 260 nm absorbing material we detected effect of extracts and, namely, of essential oils on the disruption of cytoplasmic membrane. ...

  19. Occurrence of methicillin-resistant Staphylococcus aureus in surface waters near industrial hog operation spray fields.

    Science.gov (United States)

    Hatcher, S M; Myers, K W; Heaney, C D; Larsen, J; Hall, D; Miller, M B; Stewart, J R

    2016-09-15

    Industrial hog operations (IHOs) have been identified as a source of antibiotic-resistant Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). However, few studies have investigated the presence of antibiotic-resistant S. aureus in the environment near IHOs, specifically surface waters proximal to spray fields where IHO liquid lagoon waste is sprayed. Surface water samples (n=179) were collected over the course of approximately one year from nine locations in southeastern North Carolina and analyzed for the presence of presumptive MRSA using CHROMagar MRSA media. Culture-based, biochemical, and molecular tests, as well as matrix-assisted laser desorption/ionization-time of flight mass spectrometry were used to confirm that isolates that grew on CHROMagar MRSA media were S. aureus. Confirmed S. aureus isolates were then tested for susceptibility to 16 antibiotics and screened for molecular markers of MRSA (mecA, mecC) and livestock adaptation (absence of scn). A total of 12 confirmed MRSA were detected in 9 distinct water samples. Nine of 12 MRSA isolates were also multidrug-resistant (MDRSA [i.e., resistant to ≥3 antibiotic classes]). All MRSA were scn-positive and most (11/12) belonged to a staphylococcal protein A (spa) type t008, which is commonly associated with humans. Additionally, 12 confirmed S. aureus that were methicillin-susceptible (MSSA) were recovered, 7 of which belonged to spa type t021 and were scn-negative (a marker of livestock-adaptation). This study demonstrated the presence of MSSA, MRSA, and MDRSA in surface waters adjacent to IHO lagoon waste spray fields in southeastern North Carolina. To our knowledge, this is the first report of waterborne S. aureus from surface waters proximal to IHOs.

  20. Epidemiology of Staphylococcus aureus during space flight

    Science.gov (United States)

    Pierson, D. L.; Chidambaram, M.; Heath, J. D.; Mallary, L.; Mishra, S. K.; Sharma, B.; Weinstock, G. M.

    1996-01-01

    Staphylococcus aureus was isolated over 2 years from Space Shuttle mission crewmembers to determine dissemination and retention of bacteria. Samples before and after each mission were from nasal, throat, urine, and feces and from air and surface sampling of the Space Shuttle. DNA fingerprinting of samples by digestion of DNA with SmaI restriction endonuclease followed by pulsed-field gel electrophoresis showed S. aureus from each crewmember had a unique fingerprint and usually only one strain was carried by an individual. There was only one instance of transfer between crewmembers. Strains from interior surfaces after flight matched those of crewmembers, suggesting microbial fingerprinting may have forensic application.

  1. Facts about Antibiotic Resistance

    Science.gov (United States)

    ... Cost References Español: Datos breves Facts about Antibiotic Resistance Antibiotic resistance is one of the world’s most pressing public ... antibiotic use is a key strategy to control antibiotic resistance. Antibiotic resistance in children and older adults are ...

  2. Multiple drug resistant Staphylococcus aureus strains isolated from a fish market and from fish handlers Multiresistência a antimicrobianos de cepas de Staphylococcus aureus isoladas de uma feira de pescado e de seus manipuladores

    Directory of Open Access Journals (Sweden)

    W.F. Albuquerque

    2007-03-01

    Full Text Available The aim of this study was to investigate the presence of antibiotic resistant Staphylococcus aureus strains in fish stalls and in hands and nasal and oral cavities of fish handlers of the Mucuripe Fish Market, Fortaleza, Ceará, Brazil. All S. aureus isolates were resistant to Ampicillin and 44 % were multi-drug resistant.O objetivo da pesquisa foi investigar a presença de Staphylococcus aureus resistente a antibióticos nos boxes de venda de peixe e nas mãos e cavidades nasal e oral de manipuladores de pescado da Feira de Pescado do Mucuripe, Fortaleza, Ceará. Todas as cepas isoladas foram resistentes à ampicilina e 44% apresentaram multiresistência.

  3. Potential relationship between phenotypic and molecular characteristics in revealing livestock-associated Staphylococcus aureus in Chinese humans without occupational livestock contact

    Directory of Open Access Journals (Sweden)

    Yanping Fan

    2016-09-01

    Full Text Available While some studies have defined Staphylococcus aureus based on its clonal complex and resistance pattern, few have explored the relations between the genetic lineages and antibiotic resistance patterns and immune evasion cluster (IEC genes. Our aim was to investigate the potential relationship between phenotypic and molecular characteristics so as to reveal livestock-associated S. aureus in humans. The study participants were interviewed, and they provided two nasal swabs for S. aureus analysis. All S. aureus and methicillin-resistant S. aureus (MRSA were tested for antibiotic susceptibility, multilocus sequence type and IEC genes. Of the 1162 participants, 9.3% carried S. aureus, including MRSA (1.4% and multidrug-resistant S. aureus (MDRSA, 2.8%. The predominant multidrug-resistant pattern among MDRSA isolates was nonsusceptibility to erythromycin, clindamycin and tetracycline. The most common S. aureus genotypes were ST7, ST6, ST188 and ST59, and the predominant MRSA genotype was ST7. Notably, the livestock-associated S. aureus isolates (IEC-negative CC9, IEC-negative tetracycline-resistant CC398, and IEC-negative tetracycline-resistant CC5 were found in people with no occupational livestock contact. These findings reveal a potential relationship between S. aureus CCs and IEC genes and antibiotic resistance patterns in defining livestock-associated S. aureus in humans and support growing concern about the potential livestock-to-human transmission of livestock-associated S. aureus by non-occupational livestock contact.

  4. Structural insights into the anti-methicillin-resistant Staphylococcus aureus (MRSA) activity of ceftobiprole.

    Science.gov (United States)

    Lovering, Andrew L; Gretes, Michael C; Safadi, Susan S; Danel, Franck; de Castro, Liza; Page, Malcolm G P; Strynadka, Natalie C J

    2012-09-14

    Methicillin-resistant Staphylococcus aureus (MRSA) is an antibiotic-resistant strain of S. aureus afflicting hospitals and communities worldwide. Of greatest concern is its development of resistance to current last-line-of-defense antibiotics; new therapeutics are urgently needed to combat this pathogen. Ceftobiprole is a recently developed, latest generation cephalosporin and has been the first to show activity against MRSA by inhibiting essential peptidoglycan transpeptidases, including the β-lactam resistance determinant PBP2a, from MRSA. Here we present the structure of the complex of ceftobiprole bound to PBP2a. This structure provides the first look at the molecular details of an effective β-lactam-resistant PBP interaction, leading to new insights into the mechanism of ceftobiprole efficacy against MRSA.

  5. Improved accuracy of cell surface shaving proteomics in Staphylococcus aureus using a false-positive control

    DEFF Research Database (Denmark)

    Solis, Nestor; Larsen, Martin Røssel; Cordwell, Stuart J

    2010-01-01

    Proteolytic treatment of intact bacterial cells is an ideal means for identifying surface-exposed peptide epitopes and has potential for the discovery of novel vaccine targets. Cell stability during such treatment, however, may become compromised and result in the release of intracellular proteins...... that complicate the final analysis. Staphylococcus aureus is a major human pathogen, causing community and hospital-acquired infections, and is a serious healthcare concern due to the increasing prevalence of multiple antibiotic resistances amongst clinical isolates. We employed a cell surface "shaving" technique...... lysis and were removed from the trypsin-shaved data set. We identified 42 predicted S. aureus COL surface proteins from 260 surface-exposed peptides. Trypsin and proteinase-K digests were highly complementary with ten proteins identified by both, 16 specific to proteinase-K treatment, 13 specific...

  6. Staphylococcus aureus survival in human blood.

    Science.gov (United States)

    Malachowa, Natalia; DeLeo, Frank R

    2011-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is abundant in hospitals and in the United States is a leading cause of mortality due to infectious agents. Community-associated MRSA (CA-MRSA) strains such as USA300, which typically cause disease outside of healthcare settings, are also prevalent in the United States. Although most CA-MRSA infections affect skin and soft tissue, the pathogen can enter the bloodstream and ultimately cause severe disease. In a recent paper, we used USA300-specific microarrays to generate a comprehensive view of the molecules that facilitate S. aureus immune evasion and survival in human blood. Notably, genes encoding proteins involved in iron-uptake and utilization and gamma-hemolysin (hlgABC) are highly up-regulated by USA300 during culture in human blood. Here we discuss the potential implication of these findings and the possible role of gamma-hemolysin in the success of S. aureus as a human pathogen.

  7. Genomics of Natural Populations of Staphylococcus aureus.

    Science.gov (United States)

    Fitzgerald, J Ross; Holden, Matthew T G

    2016-09-01

    Staphylococcus aureus is a major human pathogen and an important cause of livestock infections. The first S. aureus genomes to be published, 15 years ago, provided the first view of genome structure and gene content. Since then, thousands of genomes from a wide array of strains from different sources have been sequenced. Comparison of these sequences has resulted in broad insights into population structure, bacterial evolution, clone emergence and expansion, and the molecular basis of niche adaptation. Furthermore, this information is now being applied clinically in outbreak investigations to inform infection control measures and to determine appropriate treatment regimens. In this review, we summarize some of the broad insights into S. aureus biology gained from the analysis of genomes and discuss future directions and opportunities in this dynamic field of research.

  8. Eugenol Provokes ROS-Mediated Membrane Damage-Associated Antibacterial Activity Against Clinically Isolated Multidrug-Resistant Staphylococcus aureus Strains.

    Science.gov (United States)

    Das, Balaram; Mandal, Debasis; Dash, Sandeep Kumar; Chattopadhyay, Sourav; Tripathy, Satyajit; Dolai, Durga Pada; Dey, Sankar Kumar; Roy, Somenath

    2016-01-01

    Due to the indiscriminate use of antibiotics, resistance to antibiotics has increased remarkably in Staphylococcus aureus. Vancomycin is the final drug to treat the S. aureus infection, but nowadays, resistance to this antibiotic is also increasing. So, the investigation of antibiotic resistance pattern is important. As there is already resistance to vancomycin, there is an urgent need to develop a new kind of antimicrobial to treat S. aureus infection. Eugenol may be the new drug of choice. This study was conducted to evaluate the antibacterial activity of eugenol against vancomycin-resistant S. aureus isolated from clinical pus samples. Thirty six pus samples were included in the study. Samples were isolated, identified and antimicrobial susceptibility tests were performed as per routine laboratory protocol. The antimicrobial activity and mechanisms of killing of eugenol were studied. Out of 36 pus samples, only 20 isolates were confirmed as S. aureus strains and 6 isolates exhibited vancomycin resistance. Eugenol successfully destroyed the vancomycin-resistant strains via reactive oxygen species generation and membrane damage. The prevalence of vancomycin resistance is increased day by day in different countries, and necessary steps to prevent the spread and emergence of resistance should be taken. The findings of the study suggested that eugenol might be used to treat vancomycin-resistant S. aureus.

  9. Effects of Melaleuca alternifolia (Tea Tree) Essential Oil and the Major Monoterpene Component Terpinen-4-ol on the Development of Single- and Multistep Antibiotic Resistance and Antimicrobial Susceptibility

    OpenAIRE

    Hammer, Katherine A.; Carson, Christine F.; Riley, Thomas V

    2012-01-01

    This study examined the effect of subinhibitory Melaleuca alternifolia (tea tree) essential oil on the development of antibiotic resistance in Staphylococcus aureus and Escherichia coli. Frequencies of single-step antibiotic-resistant mutants were determined by inoculating bacteria cultured with or without subinhibitory tea tree oil onto agar containing 2 to 8 times the MIC of each antibiotic and with or without tea tree oil. Whereas most differences in resistance frequencies were relatively ...

  10. Evolution of methicillin-resistant Staphylococcus aureus towards increasing resistance

    DEFF Research Database (Denmark)

    Strommenger, Birgit; Bartels, Mette Damkjær; Kurt, Kevin

    2014-01-01

    To elucidate the evolutionary history of Staphylococcus aureus clonal complex (CC) 8, which encompasses several globally distributed epidemic lineages, including hospital-associated methicillin-resistant S. aureus (MRSA) and the highly prevalent community-associated MRSA clone USA300....

  11. Clp chaperones and proteases are central in stress survival, virulence and antibiotic resistance of Staphylococcus aureus

    DEFF Research Database (Denmark)

    Frees, Dorte; Gerth, Ulf; Ingmer, Hanne

    2014-01-01

    , and cell division. These observations together with recent findings that Clp proteins contribute to adaptation to antibiotics highlights the importance of this interesting proteolytic machinery both for understanding pathogenicity of the organism and for treating staphylococcal infections....

  12. Incidence of Staphylococcus aureus and analysis of associated bacterial communities on food industry surfaces.

    Science.gov (United States)

    Gutiérrez, Diana; Delgado, Susana; Vázquez-Sánchez, Daniel; Martínez, Beatriz; Cabo, Marta López; Rodríguez, Ana; Herrera, Juan J; García, Pilar

    2012-12-01

    Biofilms are a common cause of food contamination with undesirable bacteria, such as pathogenic bacteria. Staphylococcus aureus is one of the major bacteria causing food-borne diseases in humans. A study designed to determine the presence of S. aureus on food contact surfaces in dairy, meat, and seafood environments and to identify coexisting microbiota has therefore been carried out. A total of 442 samples were collected, and the presence of S. aureus was confirmed in 6.1% of samples. Sixty-three S. aureus isolates were recovered and typed by random amplification of polymorphic DNA (RAPD). Profiles were clustered into four groups which were related to specific food environments. All isolates harbored some potential virulence factors such as enterotoxin production genes, biofilm formation-associated genes, antibiotic resistance, or lysogeny. PCR-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprints of bacterial communities coexisting with S. aureus revealed the presence of bacteria either involved in food spoilage or of concern for food safety in all food environments. Food industry surfaces could thus be a reservoir for S. aureus forming complex communities with undesirable bacteria in multispecies biofilms. Uneven microbiological conditions were found in each food sector, which indicates the need to improve hygienic conditions in food processing facilities, particularly the removal of bacterial biofilms, to enhance the safety of food products.

  13. Epidemiology and antibiotic sensitivity of Staphylococcus aureus nasal carriage in children in Hungary.

    Science.gov (United States)

    Laub, Krisztina; Tóthpál, Adrienn; Kardos, Szilvia; Dobay, Orsolya

    2017-02-21

    The aim of this study was to assess the Staphylococcus aureus nasal carriage rate in healthy children all over Hungary and to specify some risk factors, the antibiotic resistance patterns of the bacteria, and their genetic relatedness. In total, 878 children (aged 3-6 years) were screened at 21 day-care centers in 16 different cities in Hungary, between February 2009 and December 2011. Samples taken from both nostrils were cultured on blood agar, and suspected S. aureus isolates were identified by β-hemolysis, catalase positivity, clump test, and nucA PCR. Methicillin-resistant strains were screened by mecA and mecC PCR. Antibiotic susceptibility was determined by agar dilution or gradient test strips. Pulsed-field gel electrophoresis was used for genotyping. S. aureus carriage rate was found to be 21.3%, which correlates well with international data. We found no statistically significant correlation between the gender or the sibling status and S. aureus carriage. All isolates were sensitive to oxacillin, trimethoprim-sulfamethoxazole, and mupirocin. The resistance rates for erythromycin, ciprofloxacin, clindamycin, gentamicin, and tetracycline were 7.5%, 0.5%, 1.1%, 3.7%, and 4.3%, respectively. The isolates showed very high genetic diversity. In summary, carried S. aureus isolates are more sensitive to antibiotics compared with clinical isolates in Hungary, and methicillin-resistant S. aureus carriage rate is very low yet.

  14. Biofilm Formation in Staphylococcus Aureus and its Relation to Phenotypic and Genotypic Criteria

    Directory of Open Access Journals (Sweden)

    Hasannejad Bibalan, M. (MSc

    2014-09-01

    Full Text Available Background and Objective: Biofilm is a complex microbial community embedded in a self-produced extracellular polymeric matrix. We aimed to study the extent of biofilm formation by S. Areas isolates and its relation to some phenotypic and genotypic criteria. Material and Methods: One hundred-fifty strains of Staphylococcus aureus isolated from Gorgan were studied. Microtiter plate assay method was used for investigation of biofilm formation.The biofilm formation of strains were recorded and its relation to accessory gene regulator (agr and antibiotic resistance were assessed by X2 test. Results: Eighty-four isolates (56% were able to form biofilm. The strength of biofilm formation in agr group I was more than that of other groups. The biofilm formation among S. Areas isolated from the wound and urine (both with 75 % had the highest capability. Methicillin-resistant isolates had a greater ability to biofilm formation. Conclusion: Methicillin resistant isolates had a greater ability to biofilm formation. Given the importance and treatment related problems of Methicillin-Resistant Staphylococcus Aureus (MRSA especially Community Acquired-Methicillin-Resistant Staphylococcus Aureus (CA-MRSA, it is a necessity to control or remove the biofilm formation alongside antibiotic treatment.

  15. Phenotypic and genotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA) from different sources in China.

    Science.gov (United States)

    Chao, Guoxiang; Zhang, Xiaoping; Zhang, Xiaorong; Huang, Yao; Xu, Lan; Zhou, Liping; Yang, Weixia; Jiang, Yuan; Xue, Feng; Wu, Yantao

    2013-03-01

    A diverse collection of 261 Staphylococcus aureus strains from human, animal, food, and environmental sources were tested for the presence and type of SCCmec elements, antibiotic susceptibility to various antibiotics, and non-ß-lactam antibiotic resistance genes. About 18.39% (48/261) of strains were methicillin-resistant S. aureus (MRSA) including 29.75% (36/121) human strains of which 29 strains were hospital-acquired MRSA (HA-MRSA) and 7 strains were community-associated MRSA (CA-MRSA) and 19.67% (12/61) animal strains that all were CA-MRSA strains. The percentage of CA-MRSA strains from animals was significantly higher than that from human (pMRSA strains and a part of methicillin-susceptible S. aureus (MSSA) strains harbored unique combinations of non-ß-lactamase genes aac(6')/aph(2″), aph(3')-III, ant (4',4″), ermA, ermC, mrsA, tetM, and tetK. Antibiotic resistance genes were detected more frequently in HA-MRSA strains than in CA-MRSA strains (pMRSA strains and MSSA strains had 22 and 39 antibiotic profiles to 15 tested antibiotics, respectively. The resistant proportion was higher in HA-MRSA strains than in CA-MSSA strains for various antibiotics, as well as higher in MRSA strains than in MSSA strains. Animal MRSA reservoirs (particularly pigs and cows) might represent an important source of human CA-MRSA. CA-MRSA strains might acquire more different resistance genes gradually, depending on the selective pressure of antibiotics in different regions or environments. CA-MRSA is not yet endemic in China, but could be prevalent in future, contributing to its acquiring more resistance genes and huge animal sources. Infection with multidrug-resistant MSSA strains acquired from food, animal, and human sources might also become a significant problem for human medicine, which warrants further study.

  16. Virulence determinants in clinical Staphylococcus aureus from monomicrobial and polymicrobial infections of diabetic foot ulcers.

    Science.gov (United States)

    Shettigar, Kavitha; Jain, Spoorthi; Bhat, Deepika V; Acharya, Raviraj; Ramachandra, Lingadakai; Satyamoorthy, Kapaettu; Murali, Thokur Sreepathy

    2016-12-01

    Antibiotic resistance in Staphylococcus aureus is a major public health concern, and methicillin-resistant S. aureus has emerged as an important pathogen. We characterized S. aureus isolates from monomicrobial and polymicrobial wound infections from 200 diabetic individuals with foot ulcers to understand their underlying diversity and pathogenicity. Staphylococcal cassette chromosome mec typing was performed, and genes coding for production of biofilm, Panton-Valentine leukocidin, toxic shock syndrome toxin and leukotoxins DE and M were screened. Biofilm production was also quantified by the tissue culture plate method. Strains were genotyped using multilocus sequence typing, multiple-locus variable number tandem repeat analysis and repetitive sequence PCR methods. Polymicrobial infections were present in 115 samples, 61 samples showed monomicrobial infection and 24 samples were culture negative. Polymicrobial infections were significantly higher in patients with previous amputation history. Of the 86 samples infected with S. aureus, virulence genes were found in 81 isolates, and 41 isolates possessed more than one virulence gene. Strains which contained pvl gene alone or luk-DE alone were significantly higher in polymicrobial wounds. Based on biofilm production, 18.6 % of isolates were classified as high, 24.4 % as moderate and 57 % as low biofilm producers. Genotyping of 30 strains revealed 10 different sequence types with a strong association among sequence types, specific virulence markers and antibiotic resistance profiles. Moreover, isolates from monomicrobial and polymicrobial wounds differed significantly in their virulence potential and the sequence types to which they belonged, and these are helpful in mapping the evolution of the identified strains of S. aureus.

  17. In vitro activity of Inula helenium against clinical Staphylococcus aureus strains including MRSA.

    LENUS (Irish Health Repository)

    O'Shea, S

    2009-01-01

    The present study aims to investigate the bactericidal activity (specifically antistaphylococcal) of Inula helenium. The antimicrobial activity of the extract is tested against 200 clinically significant Irish Staphylococcus aureus isolates consisting of methicillin-resistant (MRSA) and -sensitive (MSSA) S. aureus using a drop test method and a microbroth dilution method. The antibacterial effect is evaluated by measuring the area of the inhibition zone against the isolates. Results proved I. helenium to be 100% effective against the 200 staphylococci tested, with 93% of isolates falling within the ++ and +++ groups. The minimum bactericidal concentration of I. helenium was examined on a subset of isolates and values ranged from 0.9 mg\\/mL to 9.0 mg\\/mL. The extract was equally effective against antibiotic-resistant and -sensitive strains. This plant therefore possesses compounds with potent antistaphylococcal properties, which in the future could be used to complement infection control policies and prevent staphylococcal infection and carriage. This research supports other studies wherein herbal plants exhibiting medicinal properties are being examined to overcome the problems of antibiotic resistance and to offer alternatives in the treatment and control of infectious diseases.

  18. Minimum inhibitory concentration of ciprofloxacin in combination with hexahydroquinoline derivatives against Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    F Amin Harati

    2012-12-01

    Full Text Available Background: Staphylococcus aureus is the most common pathogen responsible for skin and soft tissue infections worldwide. Methicillin-resistant S. aureus is a major cause of both nosocomial and community acquired infections. The emergence of antimicrobial-resistant S. aureus is of global concern. Fluoroquinolone antimicrobials including ciprofloxacin, levofloxacin, and moxifloxacin are used to treat skin and soft tissue infections due to S. aureus. Emergence of ciprofloxacin resistance has increased in community acquired methicillin-resistant S. aureus strains. The aim of this study was to evaluate the minimum inhibitory concentration of ciprofloxacin and hexahydroquino-line derivatives against methicillin- and ciprofloxacin-resistant S. aureus.Methods: Identification of S. aureus was performed by routine microbiological tests in the Department of Pathobiology in Winter 2012. The susceptibility of S. aureus strains to both methicillin and ciprofloxacin was examined by the Kirby-Bauer disk-diffusion method. The minimum inhibitory concentration of ciprofloxacin, hexahydroquinoline derivatives and their combination were separately determined by broth microdilution method against methicillin- and ciprofloxacin-resistant S. aureus.Results: The minimum inhibitory concentration of ciprofloxacin decreased in the presence of hexahydroquinolinein derivatives in comparison with ciprofloxacin alone.Conclusion: This study showed that hexahydroquinoline derivatives enhance the antibacterial effect of ciprofloxacin against methicillin- and ciprofloxacin-resistant S. aureus. Therefore, these derivatives could be used as inhibitors of antibiotic resistance in combination therapies. This enhancement may be related to the inhibitory effect of hexahydroquinoline derivatives on the expression of antibiotic efflux pump in the bacteria. However, the structural features of a fluoroquinolone that determine whether it is affected by efflux transporters are not fully

  19. Methicillin-resistant Staphylococcus aureus laryngitis.

    Science.gov (United States)

    Liakos, Tracey; Kaye, Keith; Rubin, Adam D

    2010-09-01

    Infections due to methicillin-resistant Staphylococcus aureus (MRSA) have become more prevalent, in part because of the emergence and spread of community-acquired MRSA. This trend is particularly concerning because of the significant rates of morbidity and mortality associated with MRSA infections, and because MRSA strains are often resistant to many classes of antibiotics. Reports of infections of the head and neck, including wound infections, cellulitis, sinusitis, otitis media, and otitis externa, are well documented. However, to our knowledge, there have been no reports of bacterial laryngitis due to MRSA. We report the first published case of bacterial laryngitis caused by MRSA.

  20. Effects of prophylactic administration of bacteriophages to immunosuppressed mice infected with Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Borysowski Jan

    2009-08-01

    Full Text Available Abstract Background Bacteriophages can be successfully applied to treat infections caused by antibiotic-resistant bacteria. Until now no attempts have been undertaken to treat infections in immunosuppressed patients with phages. In this work we investigated the prophylactic efficacy of specific bacteriophages in CBA mice treated with cyclophosphamide (CP and infected with Staphylococcus aureus. Results High numbers of bacterial colony-forming units in the organs as well as elevated tumor necrosis factor and interleukin-6 serum concentrations in CP-treated and S. aureus-infected mice were significantly lowered upon application of phages. The phages markedly increased the percentage of circulating neutrophils and immature cells from the myelocytic and lymphocytic lineages in CP-treated, S. aureus-infected mice as well as of myelocytes and immature neutrophils in the bone marrow. In addition, phages stimulated in such mice generation of specific agglutinins against S. aureus. Conclusion Application of specific phages to immunosuppressed mice prior to infection with S. aureus proved very effective, suggesting a potential benefit of phage therapy in immunocompromised patients experiencing bacterial infections.

  1. Screening of Molecular Virulence Markers in Staphylococcus aureus and Pseudomonas aeruginosa Strains Isolated from Clinical Infections

    Science.gov (United States)

    Cotar, Ani-Ioana; Chifiriuc, Mariana-Carmen; Dinu, Sorin; Bucur, Marcela; Iordache, Carmen; Banu, Otilia; Dracea, Olguta; Larion, Cristina; Lazar, Veronica

    2010-01-01

    Staphylococcus (S.) aureus and Pseudomonas (Ps.) aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections. PMID:21614207

  2. Screening of Molecular Virulence Markers in Staphylococcus aureus and Pseudomonas aeruginosa Strains Isolated from Clinical Infections

    Directory of Open Access Journals (Sweden)

    Veronica Lazar

    2010-12-01

    Full Text Available Staphylococcus (S. aureus and Pseudomonas (Ps. aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections.

  3. Interventions for wound healing among diabetic patients infected with Staphylococcus aureus: a systematic review

    Directory of Open Access Journals (Sweden)

    Anacássia Fonseca Lima

    Full Text Available CONTEXT AND OBJECTIVE: Staphylococcus aureus is the most frequent agent isolated in diabetic foot infections and may be associated with changes to wound healing times. The aim of this study was to perform a systematic review of the literature, including studies that assessed the efficacy of any clinical or surgical intervention, as well as oral or topical therapy for diabetic ulcers infected with S. aureus. DESIGN AND SETTING: Systematic review with a search conducted in databases. METHODS: We conducted a systematic review with a comprehensive search in the Lilacs, SciELO, PubMed/Medline, Old Medline, Embase and Cochrane Library databases, for articles published from 1966 to 2010. The articles selected were limited to studies on diabetic patients with wounds infected with S. aureus for whom their healing was followed up, with the use of either antibiotics or experimental treatments. Animal studies and those that did not report the wound healing, as well as review articles, were excluded. RESULTS: Five studies that met the inclusion and exclusion criteria were analyzed. CONCLUSIONS: There are few studies reporting the healing of wounds infected with S. aureus in diabetic patients, although this is the most commonly found pathogen in this type of wound and it frequently consists of methicillin-resistant S. aureus (MRSA. There is insufficient evidence to support early use of broad-spectrum antibiotics against MRSA to promote healing of diabetic ulcers, since antibiotic resistance may develop from such treatment. This highlights the need for further studies on the subject.

  4. Mild Staphylococcus aureus skin infection improves the course of subsequent endogenous S. aureus bacteremia in mice

    NARCIS (Netherlands)

    S. van den Berg (Sanne); C.P. de Vogel (Corné); A.F. van Belkum (Alex); I.A.J.M. Bakker-Woudenberg (Irma)

    2015-01-01

    textabstractStaphylococcus aureus carriers with S. aureus bacteremia may have a reduced mortality risk compared to non-carriers. A role for the immune system is suggested. Here, we study in mice the effect of mild S. aureus skin infection prior to endogenous or exogenous S. aureus bacteremia, and ev

  5. Survival of Staphylococcus aureus on fomites.

    Science.gov (United States)

    Cuesta, Alicia; Nastri, Natalia; Bernat, Maria; Brusca, Maria; Turcot, Liliana; Nastri, Maria; Rosa, Alcira C

    2008-01-01

    The aim of this study was to evaluate duration of survival of Staphylococcus aureus on contaminated standardized fomites, such as sterilization paper (SP) and polyester previously sterilized in a steam autoclave, and to determine the potential inhibitory effects of the substrates (fabrics used to manufacture garments and special wrapping paper used in the dental setting) using the bacteriostasis test. The test was performed on two types of sterile standardized samples (T1 and T2). Sterility of the samples was validated following the protocol in use at the Department of Microbiology, after which the samples were inoculated with 50 microl of a calibrated suspension of Staphylococcus aureus (reference strain ATCC 25923) in the exponential growth phase, in a final concentration of 10(7) cfu/ml and 10(6) cfu/ml). The samples were incubated at 27 degrees C and survival and concentration of microorganisms attached to the surface of the substrates was determined at the following experimental time points: immediately post-contamination, and 3 hours, 24 hours, 3 days, and 7 days post-contamination. Recovery was determined and expressed as a percentage; the bacteriostasis test was performed and showed negative results. Our results suggest that the quantity of recovered microorganisms varies according to the type of substrate and that there is a relation between survival and incubation time of the inoculated substrate serving as an artificial niche.

  6. Low Fluid Shear Culture of Staphylococcus Aureus Represses hfq Expression and Induces an Attachment-Independent Biofilm Phenotype

    Science.gov (United States)

    Ott, C. Mark; Castro, S. L.; Nickerson, C. A.; Nelman-Gonzalez, M.

    2011-01-01

    Background: The opportunistic pathogen, Staphylococcus aureus, experiences fluctuations in fluid shear during infection and colonization of a human host. Colonization frequently occurs at mucus membrane sites such as in the gastrointestinal tract where the bacterium may experience low levels of fluid shear. The response of S. aureus to low fluid shear remains unclear. Methods: S. aureus was cultured to stationary phase using Rotating-Wall Vessel (RWV) bioreactors which produce a physiologically relevant low fluid shear environment. The bacterial aggregates that developed in the RWV were evaluated by electron microscopy as well as for antibiotic resistance and other virulence-associated stressors. Genetic expression profiles for the low-shear cultured S. aureus were determined by microarray analysis and quantitative real-time PCR. Results: Planktonic S. aureus cultures in the low-shear environment formed aggregates completely encased in high amounts of extracellular polymeric substances. In addition, these aggregates demonstrated increased antibiotic resistance indicating attachment-independent biofilm formation. Carotenoid production in the low-shear cultured S. aureus was significantly decreased, and these cultures displayed an increased susceptibility to oxidative stress and killing by whole blood. The hfq gene, associated with low-shear growth in Gram negative organisms, was also found to be down-regulated in S. aureus. Conclusions: Collectively, this data suggests that S. aureus decreases virulence characteristics in favor of a biofilm-dwelling colonization phenotype in response to a low fluid shear environment. Furthermore, the identification of an Hfq response to low-shear culture in S. aureus, in addition to the previously reported responses in Gram negative organisms, strongly suggests an evolutionarily conserved response to mechanical stimuli among structurally diverse prokaryotes.

  7. Low-shear modelled microgravity alters expression of virulence determinants of Staphylococcus aureus

    Science.gov (United States)

    Rosado, Helena; Doyle, Marie; Hinds, Jason; Taylor, Peter W.

    2010-02-01

    Microbiological monitoring of air and surfaces within the ISS indicate that bacteria of the genus Staphylococcus are found with high frequency. Staphylococcus aureus, an opportunistic pathogen with the capacity to cause severe debilitating infection, constitutes a significant proportion of these isolates. Experiments conducted during short-term flight suggest that growth in microgravity leads to increases in bacterial antibiotic resistance and to cell wall changes. Growth under low-shear modelled microgravity (LSMMG) indicated that a reduced gravitational field acts as an environmental signal for expression of enhanced bacterial virulence in gram-negative pathogens. We therefore examined the effect of simulated microgravity on parameters of antibiotic susceptibility and virulence in methicillin-susceptible S. aureus isolates RF1, RF6 and RF11; these strains were grown in a high aspect ratio vessel under LSMMG and compared with cells grown under normal gravity (NG). There were no significant differences in antibiotic susceptibility of staphylococci grown under LSMMG compared to NG. LSMMG-induced reductions in synthesis of the pigment staphyloxanthin and the major virulence determinant α-toxin were noted. Significant changes in global gene expression were identified by DNA microarray analysis; with isolate RF6, the expression of hla and genes of the regulatory system saeR/saeS were reduced approximately two-fold. These data provide strong evidence that growth of S. aureus under modelled microgravity leads to a reduction in expression of virulence determinants.

  8. Efektivitas Ekstrak Daun Jambu Biji Buah Putih Terhadap Pertumbuhan Staphylococcus aureus Dari Abses Dan Staphylococcus aureus (ATCC® 29213™)

    OpenAIRE

    Sinurat, Jojor

    2016-01-01

    Daun jambu biji mengandung senyawa aktif seperti tanin, triterpenoid, flavonoid, saponin yang mempunyai efek antibakteri. Mekanisme tanin sebagai antibakteri dengan mengkerutkan dinding sel dan membran sel, inaktivasi enzim, inaktivasi fungsi materi genetik bakteri. Flavonoid merusak sel bakteri, denaturasi protein, inaktivasi enzim dan menyebabkan lisis. Triterpenoid dan saponin menghambat pertumbuhan Staphylococcus aureus dengan cara merusak struktur membran sel. Staphylococcus aureus adala...

  9. SAMMD: Staphylococcus aureus Microarray Meta-Database

    Directory of Open Access Journals (Sweden)

    Elasri Mohamed O

    2007-10-01

    Full Text Available Abstract Background Staphylococcus aureus is an important human pathogen, causing a wide variety of diseases ranging from superficial skin infections to severe life threatening infections. S. aureus is one of the leading causes of nosocomial infections. Its ability to resist multiple antibiotics poses a growing public health problem. In order to understand the mechanism of pathogenesis of S. aureus, several global expression profiles have been developed. These transcriptional profiles included regulatory mutants of S. aureus and growth of wild type under different growth conditions. The abundance of these profiles has generated a large amount of data without a uniform annotation system to comprehensively examine them. We report the development of the Staphylococcus aureus Microarray meta-database (SAMMD which includes data from all the published transcriptional profiles. SAMMD is a web-accessible database that helps users to perform a variety of analysis against and within the existing transcriptional profiles. Description SAMMD is a relational database that uses MySQL as the back end and PHP/JavaScript/DHTML as the front end. The database is normalized and consists of five tables, which holds information about gene annotations, regulated gene lists, experimental details, references, and other details. SAMMD data is collected from the peer-reviewed published articles. Data extraction and conversion was done using perl scripts while data entry was done through phpMyAdmin tool. The database is accessible via a web interface that contains several features such as a simple search by ORF ID, gene name, gene product name, advanced search using gene lists, comparing among datasets, browsing, downloading, statistics, and help. The database is licensed under General Public License (GPL. Conclusion SAMMD is hosted and available at http://www.bioinformatics.org/sammd/. Currently there are over 9500 entries for regulated genes, from 67 microarray

  10. Aspartate inhibits Staphylococcus aureus biofilm formation.

    Science.gov (United States)

    Yang, Hang; Wang, Mengyue; Yu, Junping; Wei, Hongping

    2015-04-01

    Biofilm formation renders Staphylococcus aureus highly resistant to conventional antibiotics and host defenses. Four D-amino acids (D-Leu, D-Met, D-Trp and D-Tyr) have been reported to be able to inhibit biofilm formation and disassemble established S. aureus biofilms. We report here for the first time that both D- and L-isoforms of aspartate (Asp) inhibited S. aureus biofilm formation on tissue culture plates. Similar biofilm inhibition effects were also observed against other staphylococcal strains, including S. saprophyticus, S. equorum, S. chromogenes and S. haemolyticus. It was found that Asp at high concentrations (>10 mM) inhibited the growth of planktonic N315 cells, but at subinhibitory concentrations decreased the cellular metabolic activity without influencing cell growth. The decreased cellular metabolic activity might be the reason for the production of less protein and DNA in the matrix of the biofilms formed in the presence of Asp. However, varied inhibition efficacies of Asp were observed for biofilms formed by clinical staphylococcal isolates. There might be mechanisms other than decreasing the metabolic activity, e.g. the biofilm phenotypes, affecting biofilm formation in the presence of Asp.

  11. Toxin-Antitoxin Systems of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Christopher F. Schuster

    2016-05-01

    Full Text Available Toxin-antitoxin (TA systems are small genetic elements found in the majority of prokaryotes. They encode toxin proteins that interfere with vital cellular functions and are counteracted by antitoxins. Dependent on the chemical nature of the antitoxins (protein or RNA and how they control the activity of the toxin, TA systems are currently divided into six different types. Genes comprising the TA types I, II and III have been identified in Staphylococcus aureus. MazF, the toxin of the mazEF locus is a sequence-specific RNase that cleaves a number of transcripts, including those encoding pathogenicity factors. Two yefM-yoeB paralogs represent two independent, but auto-regulated TA systems that give rise to ribosome-dependent RNases. In addition, omega/epsilon/zeta constitutes a tripartite TA system that supposedly plays a role in the stabilization of resistance factors. The SprA1/SprA1AS and SprF1/SprG1 systems are post-transcriptionally regulated by RNA antitoxins and encode small membrane damaging proteins. TA systems controlled by interaction between toxin protein and antitoxin RNA have been identified in S. aureus in silico, but not yet experimentally proven. A closer inspection of possible links between TA systems and S. aureus pathophysiology will reveal, if these genetic loci may represent druggable targets. The modification of a staphylococcal TA toxin to a cyclopeptide antibiotic highlights the potential of TA systems as rather untapped sources of drug discovery.

  12. Toxin-Antitoxin Systems of Staphylococcus aureus.

    Science.gov (United States)

    Schuster, Christopher F; Bertram, Ralph

    2016-05-05

    Toxin-antitoxin (TA) systems are small genetic elements found in the majority of prokaryotes. They encode toxin proteins that interfere with vital cellular functions and are counteracted by antitoxins. Dependent on the chemical nature of the antitoxins (protein or RNA) and how they control the activity of the toxin, TA systems are currently divided into six different types. Genes comprising the TA types I, II and III have been identified in Staphylococcus aureus. MazF, the toxin of the mazEF locus is a sequence-specific RNase that cleaves a number of transcripts, including those encoding pathogenicity factors. Two yefM-yoeB paralogs represent two independent, but auto-regulated TA systems that give rise to ribosome-dependent RNases. In addition, omega/epsilon/zeta constitutes a tripartite TA system that supposedly plays a role in the stabilization of resistance factors. The SprA1/SprA1AS and SprF1/SprG1 systems are post-transcriptionally regulated by RNA antitoxins and encode small membrane damaging proteins. TA systems controlled by interaction between toxin protein and antitoxin RNA have been identified in S. aureus in silico, but not yet experimentally proven. A closer inspection of possible links between TA systems and S. aureus pathophysiology will reveal, if these genetic loci may represent druggable targets. The modification of a staphylococcal TA toxin to a cyclopeptide antibiotic highlights the potential of TA systems as rather untapped sources of drug discovery.

  13. The molecular evolution of methicillin-resistant Staphylococcus aureus

    NARCIS (Netherlands)

    Deurenberg, R H; Vink, C; Kalenic, S; Friedrich, A W; Bruggeman, C A; Stobberingh, E E

    2007-01-01

    Staphylococcus aureus is a potentially pathogenic bacterium that causes a broad spectrum of diseases. S. aureus can adapt rapidly to the selective pressure of antibiotics, and this has resulted in the emergence and spread of methicillin-resistant S. aureus (MRSA). Resistance to methicillin and other

  14. A pig model of acute Staphylococcus aureus induced pyemia

    DEFF Research Database (Denmark)

    Nielsen, O. L.; Iburg, T.; Aalbæk, B.;

    2009-01-01

    Background: Sepsis caused by Staphylococcus aureus constitutes an important cause of morbidity and mortality in humans, and the incidence of this disease-entity is increasing. In this paper we describe the initial microbial dynamics and lesions in pigs experimentally infected with S. aureus....... aureus isolated from man and an extension of the timeframe aiming at inducing sepsis, severe sepsis and septic shock....

  15. A novel class of cysteine protease inhibitors: solution structure of staphostatin A from Staphylococcus aureus.

    Science.gov (United States)

    Dubin, Grzegorz; Krajewski, Marcin; Popowicz, Grzegorz; Stec-Niemczyk, Justyna; Bochtler, Matthias; Potempa, Jan; Dubin, Adam; Holak, Tad A

    2003-11-25

    A series of secreted proteases are included among the virulence factors documented for Staphylococcus aureus. In light of increasing antibiotic resistance of this dangerous human pathogen, these proteases are considered as suitable targets for the development of novel therapeutic strategies. The recent discovery of staphostatins, endogenous, highly specific, staphylococcal cysteine protease inhibitors, opened a possibility for structure-based design of low molecular weight analogues. Moreover, the crystal structure of staphostatin B revealed a distinct folding pattern and an unexpected, substrate-like binding mode. The solution structure of staphostatin A reported here confirms that staphostatins constitute a novel, distinct class of cysteine protease inhibitors. In addition, the structure knowledge-based mutagenesis studies shed light on individual structural features of staphostatin A, the inhibition mechanism, and the determinants of distinct specificity of staphostatins toward their target proteases.

  16. Effect of Biosynthesized Silver Nanoparticles on Staphylococcus aureus Biofilm Quenching and Prevention of Biofilm Formation

    Institute of Scientific and Technical Information of China (English)

    Pratik R. Chaudhari∗; Shalaka A. Masurkar; Vrishali B. Shidore; Suresh P. Kamble

    2012-01-01

    The development of green experimental processes for the synthesis of nanoparticles is a need in the field of nanotechnology. The synthesis of silver nanoparticles was achieved using Bacillus cereus supernatant and 1 mM silver nitrate. 100 mM glucose was found to quicken the rate of reaction of silver nanoparticles synthesis. UV-visible spectrophotometric analysis was carried out to assess the synthesis of silver nanoparticles. The synthesized silver nanoparticles were further characterized by using Nanoparticle Tracking Analyzer (NTA), Transmission Electron Microscope and Energy Dispersive X-ray spectra. These silver nanoparticles showed enhanced quorum quenching activity against Staphylococcus aureus biofilm and prevention of biofilm formation which can be seen under inverted microscope (40 X). The synergistic effect of silver nanoparticles along with antibiotics in biofilm quenching was found to be effective. In the near future, silver nanoparticles could be used in the treatment of infections caused by highly antibiotic resistant biofilm.

  17. Community-acquired methicillin-resistant Staphylococcus aureus in Central Australia.

    Science.gov (United States)

    Stevens, Claire L; Ralph, Anna; McLeod, James E T; McDonald, Malcolm I

    2006-01-01

    To date, there has been scant information about the burden of methicillin-resistant Staphylococcus aureus infections in Central Australia. Our aims were to determine the proportion of Staphylococcus aureus infections due to methicillin-resistant strains in Central Australia, to characterise resistance to non-beta lactam antibiotics and to correlate findings with available demographic information. We retrospectively reviewed S. aureus isolates identified by the Microbiology Laboratory of the Pathology Department, Alice Springs Hospital between September 2005 and February 2006. Multi-resistance was defined as resistance to three or more non-beta lactam antibiotics. We identified the recovery site and extended antibiotic resistance profile of each isolate. Demographic data included place of residence, discharge diagnosis and ethnicity. There were 524 S. aureus isolates: 417 (79.6%) methicillin-sensitive S. aureus, 104 (19.7%) non-multi-resistant MRSA (nmrMRSA) and 3 (0.7%) multi-resistant MRSA (mrMRSA). MRSA accounted for 7/22 (32%) invasive infections and 91/474 (19.2%) cases of staphylococcal skin infections. Aboriginal people comprised 89 per cent (93/104) of patients with nmrMRSA; 57 per cent lived in remote communities, 21 per cent in suburban Alice Springs, and 18 per cent in Alice Springs Town Camps. Six per cent (6/104) of nmrMRSA were hospital-acquired. Of the nmrMRSA isolates, 57 per cent (59/104) were resistant to erythromycin and 7 per cent (7/104) to fusidic acid. All MRSA isolates were susceptible to co-trimoxazole. In conclusion, Central Australia has high rates of community-acquired nmrMRSA and low rates of multi-resistant MRSA. Erythromycin resistance in S. aureus is also common. These findings should prompt the review of antimicrobial prescribing guidelines for the region, especially for treatment of skin and soft tissue infections.

  18. SURVEILLANCE AND CONTROL OF ANTIBIOTIC RESISTANCE IN THE MEDITERRANEAN REGION

    Directory of Open Access Journals (Sweden)

    Walter Ricciardi

    2016-07-01

    Full Text Available Antibiotic resistance is one of the most relevant problems in the healthcare: the growth of resistant micro-organisms in healthcare settings is a worrisome threat, raising length to stay (LOS, morbidity and mortality in those patients. The importance of the antibiotic resistance and its spread around the world, gave rise to the activation of several surveillance systems, based especially on the collection of laboratory data to local or national level. The objective of this work is to carry out a review of the scientific literature existing on the topic and scientific activities related to surveillance on antibiotic resistance in countries bordering the Mediterranean Sea. Recent Data from European Centre for Disease Prevention and Control (November 2015 show, for different combinations bacterium-drug, an increase of resistance from North to South and from West to East of Europe; it is particularly worrying the phenomenon of resistance carried out by some gram negative, specifically Klebsiella pneumoniae and Escherichia coli to third-generation cephalosporin, often combined in opposition to fluoroquinolones and amino glycosides. Is particularly relevant the incidence of resistance to carbapenems by strains of Enterobacteriaceae (Klebsiella included. The resistance exerted by MRSA (Methicillin-resistant Staphylococcus aureus continues to be relevant, albeit showing some decline in recent years. The incidence of resistance carried on by Streptococcus pneumoniae is stable and is mainly relevant to macrolides. Finally, a significant increase in recording relatively exercised by Enterococcus faecium to Vancomycin. Detecting, preventing, and controlling antibiotic resistance requires strategic, coordinated, and sustained efforts. It also depends on the engagement of governments, academia, industry, healthcare providers, the general public, and the agricultural community, as well as international partners. Committing to combating antibiotic-resistant

  19. Phenotypic and genotypic characterization of methicillin-resistant Staphylococcus aureus from bovine mastitis

    Directory of Open Access Journals (Sweden)

    S. Hamid

    2017-03-01

    Full Text Available Aim: This study was conducted to determine the occurrence of methicillin-sensitive and Staphylococcus aureus (MSSA methicillin-resistant S. aureus (MRSA from bovine mastitis and to characterize them with respect to antibiotic resistance gene mecA. Materials and Methods: A total of 160 mastitic milk samples were screened for the presence of S. aureus. The presumptive positive isolates were confirmed using nuc and 23S rRNA gene-based polymerase chain reaction. All the confirmed isolates were subjected to in vitro antibiogram using a number of antibiotics. Isolates which showed resistance against methicillin were characterized for the presence of mecA gene. Results: Out of the total 160 milk samples, 36 (22.5% samples yielded S. aureus. The in vitro antibiogram revealed that 16.6% S. aureus isolates were resistant to all antibiotics screened for and 5.5% isolates were sensitive to all of them. Furthermore, the study found 94.4%, 83.3%, 77.7%, 66.6%, 50%, and 27.7% of S. aureus isolates resistant to penicillin, ampicillin, amoxicillin-sulbactam, enrofloxacin, ceftriaxone, and methicillin, respectively. Out of the 36 S. aureus isolates, only 6 (16.6% isolates were confirmed as MRSA while rest were MSSA. Conclusion: The higher occurrence of S. aureus-mediated mastitis was concluded due to improper hygienic and poor farm management. The multiple drug resistance reveals the indiscriminate use of drugs and presence of methicillin resistance gene determinant is an alarming situation as such infections are difficult to treat.

  20. Beta-lactamase Escherichia coli and Staphylococcus aureus isolated from chickens in Nigeria

    Directory of Open Access Journals (Sweden)

    Godwin Onyemaechi Egwu

    2010-06-01

    Full Text Available The occurrence of beta-lactamase-producing Escherichia coli and Staphylococcus aureus in chickens was investigated. Specimens (n = 1 300 were collected from 400 chickens and were streaked on MacConkey agar plates. From each plate, presumptive growths of organisms were picked and streaked on eosin methylene blue and Baird-Parker agars, respectively. Typical colonies of E. coli and S. aureus with similar morphologies were identified by biochemical tests. Isolates were tested for beta-lactamase production and antimicrobial susceptibilities. Results indicated that 805 E. coli isolates from which 89 (11% were beta-lactamase-positive and 660 S. aureus from which 58 (8.8% were beta-lactamase-positive. Both isolates showed a high level of resistance to all twelve antibiotics screened. The increased prevalence of antibiotic resistance amongst bacterial organisms is undoubtedly correlated with the discovery and characterisation of multiple, transferrable resistance determinants, such as beta-lactamases, corresponding to their respective phenotypes. The implications of this for humans when handling and/or consuming chickens and chicken products contaminated with strains of such isolates, is a risk of transferrable multi-drug resistance and a failure of treatment. The results of our study indicated that beta-lactamase-producing E. coli and S. aureus are prevalent in chickens in Nigeria.

  1. Development of ebsulfur analogues as potent antibacterials against methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Ngo, Huy X; Shrestha, Sanjib K; Green, Keith D; Garneau-Tsodikova, Sylvie

    2016-12-15

    Antibiotic resistance is a worldwide problem that needs to be addressed. Staphylococcus aureus is one of the dangerous "ESKAPE" pathogens that rapidly evolve and evade many current FDA-approved antibiotics. Thus, there is an urgent need for new anti-MRSA compounds. Ebselen (also known as 2-phenyl-1,2-benzisoselenazol-3(2H)-one) has shown promising activity in clinical trials for cerebral ischemia, bipolar disorder, and noise-induced hearing loss. Recently, there has been a renewed interest in exploring the antibacterial properties of ebselen. In this study, we synthesized an ebselen-inspired library of 33 compounds where the selenium atom has been replaced by sulfur (ebsulfur derivatives) and evaluated them against a panel of drug-sensitive and drug-resistant S. aureus and non-S. aureus strains. Within our library, we identified three outstanding analogues with potent activity against all S. aureus strains tested (MIC values mostly ⩽2μg/mL), and numerous additional ones with overall very good to good antibacterial activity (1-7.8μg/mL). We also characterized the time-kill analysis, anti-biofilm ability, hemolytic activity, mammalian cytotoxicity, membrane-disruption ability, and reactive oxygen species (ROS) production of some of these analogues.

  2. RNA-Seq reveals changes in the Staphylococcus aureus transcriptome following blue light illumination.

    Science.gov (United States)

    Adair, Tamarah L; Drum, Bayless E

    2016-09-01

    In an effort to better understand the mechanism by which blue light inhibits the growth of Staphylococcus aureus in culture, a whole transcriptome analysis of S. aureus isolate BUSA2288 was performed using RNA-Seq to analyze the differential gene expression in response to blue light exposure. RNA was extracted from S. aureus cultures pooled from 24 1 ml well samples that were each illuminated with a dose of 250 J/cm(2) of 465 nm blue light and from control cultures grown in the dark. Complementary DNA libraries were generated from enriched mRNA samples and sequenced using the Illumina MiSeq Next Generation Sequencer. Here we report one type of analysis that identified 32 candidate genes for further investigation. Blue light has been shown to be bactericidal against S. aureus and is a potential alternative therapy for antibiotic resistant organisms. The mechanism for the inactivation of bacteria is hypothesized to involve reactive oxygen species. These RNA-Seq results provide data that may be used to test this hypothesis. The RNA-Seq data generated by these experiments is deposited in Gene Expression Omnibus (Gene accession GSE62055) and may be found at NCBI (http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE62055).

  3. Characterization of Methicillin-Resistant Staphylococcus aureus Isolated from Healthy Turkeys and Broilers Using DNA Microarrays

    Science.gov (United States)

    El-Adawy, Hosny; Ahmed, Marwa; Hotzel, Helmut; Monecke, Stefan; Schulz, Jochen; Hartung, Joerg; Ehricht, Ralf; Neubauer, Heinrich; Hafez, Hafez M.

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a major human health problem and recently, domestic animals are described as carriers and possible reservoirs. Twenty seven S. aureus isolates from five turkey farms (n = 18) and two broiler farms (n = 9) were obtained by culturing of choana and skin swabs from apparently healthy birds, identified by Taqman-based real-time duplex nuc-mecA-PCR and characterized by spa typing as well as by a DNA microarray based assay which covered, amongst others, a considerable number of antibiotic resistance genes, species controls, and virulence markers. The antimicrobial susceptibility profiles were tested by agar diffusion assays and genotypically confirmed by the microarray. Five different spa types (3 in turkeys and 2 in broilers) were detected. The majority of MRSA isolates (24/27) belonged to clonal complex 398-MRSA-V. The most frequently occurring spa types were accordingly t011, t034, and t899. A single CC5-MRSA-III isolated from turkey and CC398-MRSA with an unidentified/truncated SCCmec element in turkey and broiler were additionally detected. The phenotypic antimicrobial resistance profiles of S. aureus isolated from both turkeys and broilers against 14 different antimicrobials showed that all isolates were resistant to ampicillin, cefoxitin, oxacillin, doxycycline, and tetracycline. Moreover, all S. aureus isolated from broilers were resistant to erythromycin and azithromycin. All isolates were susceptible to gentamicin, chloramphenicol, sulphonamides, and fusidic acid. The resistance rate against ciprofloxacin was 55.6% in broiler isolates and 42.1% in turkey isolates. All tetracycline resistant isolates possessed genes tetK/M. All erythromycin-resistant broiler isolates carried ermA. Only one broiler isolate (11.1%) carried genes ermA, ermB, and ermC, while 55.6% of turkey isolates possessed ermA and ermB genes. Neither PVL genes (lukF/S-PV), animal-associated leukocidin (lukM and luk-P83) nor the gene encoding

  4. Antibiotic resistance in Chlamydiae.

    Science.gov (United States)

    Sandoz, Kelsi M; Rockey, Daniel D

    2010-09-01

    There are few documented reports of antibiotic resistance in Chlamydia and no examples of natural and stable antibiotic resistance in strains collected from humans. While there are several reports of clinical isolates exhibiting resistance to antibiotics, these strains either lost their resistance phenotype in vitro, or lost viability altogether. Differences in procedures for chlamydial culture in the laboratory, low recovery rates of clinical isolates and the unknown significance of heterotypic resistance observed in culture may interfere with the recognition and interpretation of antibiotic resistance. Although antibiotic resistance has not emerged in chlamydiae pathogenic to humans, several lines of evidence suggest they are capable of expressing significant resistant phenotypes. The adept ability of chlamydiae to evolve to antibiotic resistance in vitro is demonstrated by contemporary examples of mutagenesis, recombination and genetic transformation. The isolation of tetracycline-resistant Chlamydia suis strains from pigs also emphasizes their adaptive ability to acquire antibiotic resistance genes when exposed to significant selective pressure.

  5. Identification and Characterization of Staphylococcus aureus Strains with an Incomplete Hemolytic Phenotype

    Directory of Open Access Journals (Sweden)

    Haifang Zhang

    2016-11-01

    Full Text Available Staphylococcus aureus is a common pathogen causing both hospital and community-acquired infections. Hemolysin is one of the important virulence factors for S. aureus and causes the typical β-hemolytic phenotype which is called complete hemolytic phenotype as well. Recently, Staphylococcus aureus with an incomplete hemolytic phenotype (SIHP was isolated from clinical samples. To study the microbiologic characteristics of SIHP, SIHP was inoculated on the sheep blood agar plates supplied by different manufacturers to compare their hemolytic phenotype. Expression of hemolysin genes hla, hlb, hlgC and hld of SIHP was detected by qRT-PCR. In addition, the alpha-hemolysin encoded by gene hla was analyzed by western blot. At the same time, the antimicrobial susceptibility of SIHP was tested using the broth dilution method. The main antibiotic resistance gene mecA and virulence genes tst were detected by PCR in SIHP strains. Furthermore, the virulence of SIHP strains was detected through comparing their intracellular survival in macrophage. The cytokines and chemokines secreted by macrophage were measured by flow cytometry. Finally, the genotyping of SIHP was performed by multilocus sequence typing (MLST analysis. The results showed that the incomplete hemolytic phenotype of SIHP could be observed on the sheep blood agar plates from different suppliers. The relative mRNA expression of hlb in SIHP was obviously increased compared to the control Staphylococcus aureus strains, while the expression of hla, hlgC and hld in SIHP was significantly decreased. In addition, it was shown that the alpha-hemolysin of SIHP was less than that of control strains as well. All sixty SIHP strains were identified to be the methicillin resistant Staphylococcus aureus (MRSA, and moreover these SIHP strains all contains mecA gene. The virulence gene tst were all present in SIHP, and the intracellular survival ability of SIHP was much greater than that of the gene tst negative

  6. Antibiotic resistance genes detected by multiplex PCR assays in Staphylococcus epidermidis strains isolated from dialysis fluid and needles in a dialysis service.

    Science.gov (United States)

    Chaieb, Kamel; Zmantar, Tarek; Chehab, Olfa; Bouchami, Ons; Ben Hasen, Assia; Mahdouani, Kacem; Bakhrouf, Amina

    2007-07-01

    The rate of the onset of methicillin-resistant Staphylococcus epidermidis infections is increasing in Tunisia. We have isolated 32 S. epidermidis strains from dialysis fluid and needle cultures in dialysis service. The strains were identified by classic methods (colonial morphology, Gram staining, catalase test, coagulase test, and DNase test) as well as by API ID32 Staph. Susceptibilities to 18 antibiotics were tested with the ATB Staph kit. Most of the tested strains were resistant to penicillin. In addition, the presence of multidrug resistant strains that showed resistance to different antibiotics was recorded. We have characterized these strains by multiplex PCR assay to identify intercellular adhesion genes icaA/icaD associated with the adhesiveness of staphylococci in biomaterials, and to identify representative resistant genes: oxacillin resistance, mecA; erythromycin methylase (ermA, ermB, and ermC), and macrolide efflux gene (msrA and mef). The frequency of the carriage of these genes was icaA/icaD (71.9%), mecA (78.1%), ermA (12.5%), ermB (31.3%), ermC (53.1%), msrA (68.8%), and mef (O%). Although the carriage of the genes and the results of susceptibility testing did not match exactly, it could be judged that the PCR identification of antibiotic resistance genes is rapid and supplementary methods for identifying staphylococci or epidemiological study used for the control of nosocomial infection.

  7. Comparative Whole-Genome Mapping To Determine Staphylococcus aureus Genome Size, Virulence Motifs, and Clonality

    Science.gov (United States)

    Pantrang, Madhulatha; Stahl, Buffy; Briska, Adam M.; Stemper, Mary E.; Wagner, Trevor K.; Zentz, Emily B.; Callister, Steven M.; Lovrich, Steven D.; Henkhaus, John K.; Dykes, Colin W.

    2012-01-01

    Despite being a clonal pathogen, Staphylococcus aureus continues to acquire virulence and antibiotic-resistant genes located on mobile genetic elements such as genomic islands, prophages, pathogenicity islands, and the staphylococcal chromosomal cassette mec (SCCmec) by horizontal gene transfer from other staphylococci. The potential virulence of a S. aureus strain is often determined by comparing its pulsed-field gel electrophoresis (PFGE) or multilocus sequence typing profiles to that of known epidemic or virulent clones and by PCR of the toxin genes. Whole-genome mapping (formerly optical mapping), which is a high-resolution ordered restriction mapping of a bacterial genome, is a relatively new genomic tool that allows comparative analysis across entire bacterial genomes to identify regions of genomic similarities and dissimilarities, including small and large insertions and deletions. We explored whether whole-genome maps (WGMs) of methicillin-resistant S. aureus (MRSA) could be used to predict the presence of methicillin resistance, SCCmec type, and Panton-Valentine leukocidin (PVL)-producing genes on an S. aureus genome. We determined the WGMs of 47 diverse clinical isolates of S. aureus, including well-characterized reference MRSA strains, and annotated the signature restriction pattern in SCCmec types, arginine catabolic mobile element (ACME), and PVL-carrying prophage, PhiSa2 or PhiSa2-like regions on the genome. WGMs of these isolates accurately characterized them as MRSA or methicillin-sensitive S. aureus based on the presence or absence of the SCCmec motif, ACME and the unique signature pattern for the prophage insertion that harbored the PVL genes. Susceptibility to methicillin resistance and the presence of mecA, SCCmec types, and PVL genes were confirmed by PCR. A WGM clustering approach was further able to discriminate isolates within the same PFGE clonal group. These results showed that WGMs could be used not only to genotype S. aureus but also to

  8. Curcumin Reverse Methicillin Resistance in Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Su-Hyun Mun

    2014-11-01

    Full Text Available Curcumin, a natural polyphenolic flavonoid extracted from the rhizome of Curcuma longa L., was shown to possess superior potency to resensitize methicillin-resistant Staphylococcus aureus (MRSA to antibiotics. Previous studies have shown the synergistic activity of curcumin with β-lactam and quinolone antibiotics. Further, to understand the anti-MRSA mechanism of curcumin, we investigated the potentiated effect of curcumin by its interaction in diverse conditions. The mechanism of anti-MRSA action of curcumin was analyzed by the viability assay in the presence of detergents, ATPase inhibitors and peptidoglycan (PGN from S. aureus, and the PBP2a protein level was analyzed by western blotting. The morphological changes in the curcumin-treated MRSA strains were investigated by transmission electron microscopy (TEM. We analyzed increased susceptibility to MRSA isolates in the presence of curcumin. The optical densities at 600 nm (OD600 of the suspensions treated with the combinations of curcumin with triton X-100 and Tris were reduced to 63% and 59%, respectively, compared to curcumin without treatment. N,N'-dicyclohexylcarbodiimide (DCCD and sodium azide (NaN3 were reduced to 94% and 55%, respectively. When peptidoglycan (PGN from S. aureus was combined with curcumin, PGN (0–125 μg/mL gradually blocked the antibacterial activity of curcumin (125 μg/mL; however, at a concentration of 125 µg/mL PGN, it did not completely block curcumin. Curcumin has a significant effect on the protein level of PBP2a. The TEM images of MRSA showed damage of the cell wall, disruption of the cytoplasmic contents, broken cell membrane and cell lysis after the treatment of curcumin. These data indicate a remarkable antibacterial effect of curcumin, with membrane permeability enhancers and ATPase inhibitors, and curcumin did not directly bind to PGN on the cell wall. Further, the antimicrobial action of curcumin involved in the PBP2a-mediated resistance mechanism was

  9. A porcine model of haematogenous brain infectionwith staphylococcus aureus

    DEFF Research Database (Denmark)

    Astrup, Lærke Boye; Agerholm, Jørgen Steen; Nielsen, Ole Lerberg;

    2012-01-01

    A PORCINE MODEL OF HAEMATOGENOUS BRAIN INFECTION WITH STAPHYLOCOCCUS AUREUS Astrup Lærke1, Agerholm Jørgen1, Nielsen Ole1, Jensen Henrik1, Leifsson Páll1, Iburg Tine2. 1: Faculty of Health and Medical Sciences, University of Copenhagen, Denmark boye@life.ku.dk 2: National Veterinary Institute......, Uppsala, Sweden Introduction Staphylococcus aureus (S.aureus) is a common cause of sepsis and brain abscesses in man and a frequent cause of porcine pyaemia. Here we present a porcine model of haematogenous S. aureus-induced brain infection. Materials and Methods Four pigs had two intravenous catheters...

  10. Staphylococcus aureus methicillin resistance detected by HPLC-MS/MS targeted metabolic profiling.

    Science.gov (United States)

    Schelli, Katie; Rutowski, Joshua; Roubidoux, Julia; Zhu, Jiangjiang

    2017-03-15

    Recently, novel bioanalytical methods, such as NMR and mass spectrometry based metabolomics approaches, have started to show promise in providing rapid, sensitive and reproducible detection of Staphylococcus aureus antibiotic resistance. Here we performed a proof-of-concept study focused on the application of HPLC-MS/MS based targeted metabolic profiling for detecting and monitoring the bacterial metabolic profile changes in response to sub-lethal levels of methicillin exposure. One hundred seventy-seven targeted metabolites from over 20 metabolic pathways were specifically screened and one hundred and thirty metabolites from in vitro bacterial tests were confidently detected from both methicillin susceptible and methicillin resistant Staphylococcus aureus (MSSA and MRSA, respectively). The metabolic profiles can be used to distinguish the isogenic pairs of MSSA strains from MRSA strains, without or with sub-lethal levels of methicillin exposure. In addition, better separation between MSSA and MRSA strains can be achieved in the latter case using principal component analysis (PCA). Metabolite data from isogenic pairs of MSSA and MRSA strains were further compared without and with sub-lethal levels of methicillin exposure, with metabolic pathway analyses additionally performed. Both analyses suggested that the metabolic activities of MSSA strains were more susceptible to the perturbation of the sub-lethal levels of methicillin exposure compared to the MRSA strains.

  11. Improving Diagnosis and Treatment of Staphylococcus aureus Infections : Experimental Studies

    NARCIS (Netherlands)

    S. van den Berg (Sanne)

    2015-01-01

    markdownabstract__Abstract__ Staphylococcus aureus is an opportunistic pathogen that causes a variety of infections, ranging from mild skin infections like furuncles and impetigo, to severe, lifethreatening infections including endocarditis, osteomyelitis and pneumonia. Invasive infections are freq

  12. Long-term mortality after Staphylococcus aureus spondylodiscitis

    DEFF Research Database (Denmark)

    Aagaard, Theis; Larsen, Anders R; Roed-Petersen, Casper;

    2014-01-01

    Patients diagnosed with Staphylococcus aureus spondylodiscitis have increased long-term mortality compared with the background population mainly due to infectious, endocrine, cardiovascular, gastrointestinal and alcohol and drug abuse-related diseases.......Patients diagnosed with Staphylococcus aureus spondylodiscitis have increased long-term mortality compared with the background population mainly due to infectious, endocrine, cardiovascular, gastrointestinal and alcohol and drug abuse-related diseases....

  13. IDENTIFIKASI MIKROORGANISE STAPHYLOCOCCUS AUREUS PADA PENDERITA ANGULAR CHEILITIS

    OpenAIRE

    MINARTI, NURHAERATUL

    2012-01-01

    2011 Pada suatu penelitian tentang Angular cheilitis ditemukan Staphylococcus aureus hampir dua kali dari candida albicans. Oleh karena itu tujuan penelitian ini adalah untuk mengidentifikasi pengaruh Staphylococcus aureus pada penyakit Angular cheilitis. Sampel penelitian adalah 30 pasien yang datang ke Rumah Sakit Gigi dan Mulut Halimah Daeng Sikati Kandea Bagian Penyakit Gigi dan Mulut dalam periode waktu bulan Oktober-November 2011. Apusan pada permukaan lesi angular cheilitis dima...

  14. Pathogenic Staphylococcus aureus Isolates from Postoperative Wounds of Hospitalized Patients

    Directory of Open Access Journals (Sweden)

    Smritikana Biswas

    2010-07-01

    Full Text Available Staphylococcus sp., gram positive pyogenic bacteria located on skin, nose etc, secretes toxin that causes toxic shock syndrome, abscess, food poisoning and other infectious diseases. This study was carried out to identify and characterize the type of Staphylococcus sp. bacteria especially Staphylococcus aureus in the pus from postoperative wounds of hospitalized patients. From pus samples collected from twenty-four patients from Kharagpur Hospital, Paschim Medinipur, West Bengal, twenty-eight bacterial isolates were obtained. Among them twenty-five (89.2% were appeared with golden yellow colonies which is usually formed by Staphylococcus aureus. Twenty-three (82.14% of the bacterial isolates were Gram positive. Among them twenty isolates (86.9% were further confirmed to be Staphylococcus aureus by their ability to produce Catalase enzyme (positive in Catalase test and Coagulase enzyme (positive in Coagulase Test. Eighteen (90.00% of these Staphylococcus aureus were found to liquefy gelatin (Gelatin hydrolysis test, were able to hydrolyze urea (Urea hydrolysis test and were also l positive in Mannitol Fermentation Test. But there was no growth found of these isolates on MacConkey Agar, while sixteen isolates (80.00% of Staphylococcus aureus were resistant to penicillin (50µg/ml. Moreover eighteen (90.00% Staphylococcus aureus isolates were able to elaborate Hemolysin (Hemolysis test on Blood Agar media. Hence the bacterial isolates obtained from pus of postoperative wounds were predominantly pathogenic Staphylococcus aureus. So it can be concluded that careful treatment and postoperative measures to be taken to avoid serious health problem that may often be life threatening.

  15. Antibacterial effect of silver nanoparticles along with protein synthesis-inhibiting antibiotics on Staphylococcus aureus isolated from cattle mastitis

    Directory of Open Access Journals (Sweden)

    Malahat Ahmadi

    2014-01-01

    Full Text Available Introduction: Staphylococcus aureus is an opportunistic pathogen in dairy ruminants which is also found in healthy carriage and can be a major cause of mastitis. Various mastitis control programs have been used to combat the problem but have not always been efficient. In most countries, antibiotic resistance is extremely common. Silver nanoparticles have shown antimicrobial activity against S. aureus. In the present study the effect of silver nanoparticles on S. aureus isolated from cattle mastitis along with antibiotics of operative on protein bacterial synthesis investigated. Materials and methods: Three hundred eleven milk samples were collected from the cow farms. Each milk sample was cultured on mannitol salt agar and was incubated. A total of 72 isolates of S. aureus were isolated from the bovine mastitis milk samples. S. aureus DNA extracted by DNA purification kit according to the manufacturer protocol. 58 isolates were confirmed as S. aureus by biochemical tests as well as nuc gene detection. MIC and MBC determined for silver nanoparticles with antibiotics on 50 isolates. Results: The resistance of S. aureus isolates against erythromycin, gentamicin, streptomycin and doxycycline were 100, 22, 100 and 8%, respectively. 8 of all isolates were sensitive to 25 µg/ml concentration of silver nanoparticles. The 92% growth of the samples were inhibited at concentrations between 50-100 µg/ml. Discussion and conclusion: The present study suggests that antibiotics which can inhibit protein synthesis have significant synergistic effect along with silver nanoparticles.

  16. Amidase, a cell wall hydrolase, elicits protective immunity against Staphylococcus aureus and S. epidermidis.

    Science.gov (United States)

    Nair, Nisha; Vinod, Vivek; Suresh, Maneesha K; Vijayrajratnam, Sukhithasri; Biswas, Lalitha; Peethambaran, Reshmi; Vasudevan, Anil Kumar; Biswas, Raja

    2015-01-01

    The morbidity and the mortality associated with Staphylococcus aureus and S. epidermidis infections have greatly increased due to the rapid emergence of highly virulent and antibiotic resistant strains. Development of a vaccine-based therapy is greatly desired. However, no staphylococcal vaccine is available till date. In this study, we have identified Major amidase (Atl-AM) as a prime candidate for future vaccine design against these pathogens. Atl-AM is a multi-functional non-covalently cell wall associated protein which is involved in staphylococcal cell separation after cell division, host extracellular matrix adhesion and biofilm formation. Atl-AM is present on the surface of diverse S. aureus and S. epidermidis strains. When used in combination with Freund's adjuvant, Atl-AM generated a mixed Th1 and Th2 mediated immune response which is skewed more toward Th1; and showed increased production of opsonophagocytic IgG2a and IgG2b antibodies. Significant protective immune response was observed when vaccinated mice were challenged with S. aureus or S. epidermidis. Vaccination prevented the systemic dissemination of both organisms. Our results demonstrate the remarkable efficacy of Atl-AM as a vaccine candidate against both of these pathogens.

  17. Detection of methicillin-resistant Staphylococcus aureus (MRSA) using the NanoLantern Biosensor

    Science.gov (United States)

    Strohsahl, Christopher M.; Miller, Benjamin L.; Krauss, Todd D.

    2009-02-01

    Staphylococcus aureus is a leading cause of human illness, and has developed the remarkable ability to resist the bactericidal capabilities of many of the world's leading antibiotics (i.e. MRSA). In an effort to enable rapid detection and treatment of MRSA infections, we have developed a DNA detection technology termed the NanoLantern(TM). The NanoLantern(TM) biosensor technology is based on the simple immobilization of a fluorophore-terminated DNA hairpin onto a gold chip. This produces a label-free sensor that allows for a positive response to be obtained without extensive processing of the sample, saving cost and increasing accuracy. We will also discuss a newly developed method of partial gene analysis, used to develop a DNA hairpin probe that is capable of detecting the presence of the mecR gene, a gene necessary for methicillin resistance to be present in S. aureus, with 100% sequence specificity. The successful incorporation of this probe into the NanoLantern(TM) platform, along with the concomitant development of the paired PCR assay has allowed for the successful detection of methicillin-resistance directly from a culture of S. aureus. These results represent an important step forward in terms of developing the ability to rapidly and effectively detect the presence of antibiotic resistance in bacterial infections.

  18. Microbiological and molecular assessment of bacteriophage ISP for the control of Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Katrien Vandersteegen

    Full Text Available The increasing antibiotic resistance in bacterial populations requires alternatives for classical treatment of infectious diseases and therefore drives the renewed interest in phage therapy. Methicillin resistant Staphylococcus aureus (MRSA is a major problem in health care settings and live-stock breeding across the world. This research aims at a thorough microbiological, genomic, and proteomic characterization of S. aureus phage ISP, required for therapeutic applications. Host range screening of a large batch of S. aureus isolates and subsequent fingerprint and DNA microarray analysis of the isolates revealed a substantial activity of ISP against 86% of the isolates, including relevant MRSA strains. From a phage therapy perspective, the infection parameters and the frequency of bacterial mutations conferring ISP resistance were determined. Further, ISP was proven to be stable in relevant in vivo conditions and subcutaneous as well as nasal and oral ISP administration to rabbits appeared to cause no adverse effects. ISP encodes 215 gene products on its 138,339 bp genome, 22 of which were confirmed as structural proteins using tandem electrospray ionization-mass spectrometry (ESI-MS/MS, and shares strong sequence homology with the 'Twort-like viruses'. No toxic or virulence-associated proteins were observed. The microbiological and molecular characterization of ISP supports its application in a phage cocktail for therapeutic purposes.

  19. Orthosiphon stamineus protects Caenorhabditis elegans against Staphylococcus aureus infection through immunomodulation

    Directory of Open Access Journals (Sweden)

    Cin Kong

    2014-06-01

    Full Text Available Amidst growing concerns over the spread of antibiotic-resistant Staphylococcus aureus strains, the identification of alternative therapeutic molecules has become paramount. Previously, we utilized a Caenorhabditis elegans–S. aureus screening platform to identify potential anti-infective agents from a collection of natural extracts and synthetic compounds. One of the hits obtained from the screen was the aqueous extract of Orthosiphon stamineus leaves (UE-12 that enhanced the survival of infected nematodes without interfering with bacterial growth. In this study, we used a fluorescent transgenic reporter strain and observed that the repressed expression of the lys-7 defense gene in infected nematodes was restored in the presence of UE-12. Analysis of a selected panel of PMK-1 and DAF-16-regulated transcripts and loss-of-function mutants in these pathways indicates that the protective role of UE-12 is mediated via the p38 MAP kinase and insulin-like signaling pathways. Further analysis of a panel of known bioactive compounds of UE-12 proposed eupatorin (C18H16O7 as the possible candidate active molecule contributing to the anti-infective property of UE-12. Taken together, these findings strongly suggest that the O. stamineus leaf extract is a promising anti-infective agent that confers an advantage in survival against S. aureus infection by modulating the immune response of the infected host.

  20. Detection and identification of methicillin resistant and sensitive strains of Staphylococcus aureus using tandem measurements.

    Science.gov (United States)

    Guntupalli, Rajesh; Sorokulova, Iryna; Olsen, Eric; Globa, Ludmila; Pustovyy, Oleg; Moore, Timothy; Chin, Bryan; Barbaree, James; Vodyanoy, Vitaly

    2012-09-01

    Discrimination of methicillin resistant (MRSA) and sensitive (MSSA) strains of Staphylococcus aureus, was achieved by the specially selected lytic bacteriophage with a wide host range of S. aureus strains and a penicillin-binding protein (PBP 2a) specific antibody. A quartz crystal microbalance with dissipation monitoring (QCM-D) was employed to analyze bacteria-phage interactions. The lytic phages were transformed into phage spheroids by exposure to water-chloroform interface. Phage spheroid monolayers were transferred onto QCM-D sensors by Langmuir-Blodgett (LB) technique. Biosensors were tested in the flow mode with bacterial water suspensions, while collecting frequency and energy dissipation changes. Bacteria-spheroid interactions resulted in decreased resonance frequency and an increase in dissipation energy for both MRSA and MSSA strains. Following the bacterial binding, these sensors were further exposed to a flow of the penicillin-binding protein (PBP 2a) specific antibody conjugated latex beads. Sensors tested with MRSA responded to PBP 2a antibody beads; while sensors examined with MSSA gave no response. This experimental difference establishes an unambiguous discrimination between methicillin resistant and sensitive S. aureus strains. Both free and immobilized bacteriophages strongly inhibit bacterial growth on solid/air interfaces and in water suspensions. After lytic phages are transformed into spheroids, they retain their strong lytic activity and demonstrate high bacterial capture efficiency. The phage and phage spheroids can be used for screening and disinfection of antibiotic resistant bacteria. Other applications may include use on biosensors, bacteriophage therapy, and antimicrobial surfaces.

  1. Regulatory Mutations Impacting Antibiotic Susceptibility in an Established Staphylococcus aureus Biofilm.

    Science.gov (United States)

    Atwood, Danielle N; Beenken, Karen E; Lantz, Tamara L; Meeker, Daniel G; Lynn, William B; Mills, Weston B; Spencer, Horace J; Smeltzer, Mark S

    2016-01-11

    We previously determined the extent to which mutations of different Staphylococcus aureus regulatory loci impact biofilm formation as assessed under in vitro conditions. Here we extend these studies to determine the extent to which those regulatory loci that had the greatest effect on biofilm formation also impact antibiotic susceptibility. The experiments were done under in vitro and in vivo conditions using two clinical isolates of S. aureus (LAC and UAMS-1) and two functionally diverse antibiotics (daptomycin and ceftaroline). Mutation of the staphylococcal accessory regulator (sarA) or sigB was found to significantly increase susceptibilities to both antibiotics and in both strains in a manner that could not be explained by changes in the MICs. The impact of a mutation in sarA was comparable to that of a mutation in sigB and greater than the impact observed with any other mutant. These results suggest that therapeutic strategies targeting sarA and/or sigB have the greatest potential to facilitate the ability to overcome the intrinsic antibiotic resistance that defines S. aureus biofilm-associated infections.

  2. Implantation of Corynebacterium pseudodiphtheriticum for elimination of Staphylococcus aureus from the nasal cavity in volunteers

    Science.gov (United States)

    Viacheslav, Ilyin; Kiryukhina, Nataliya

    Nasal carriage of Staphylococcus aureus is a well-documented risk factor of infection and inflammation of the skin, soft tissues and bacteremia. It is also known that most often etiology of these disorders is associated with autoinfection. The present-day methods of opportunistic pathogens eradication from the nasal cavity are based principally on the use of antiseptic and antibacterial agents. For instance, a local antibiotic mupirocin in the form of nasal ointment is considered to be the gold standard for the treatment of S. aureus carriage. The literature describes investigations showing how mupirocin can strengthen antibiotic resistance in S. aureus strains, including those with methicillin resistance (MRSA). It is also common knowledge that recolonization of the nasal mucous membrane takes place within several months after mupirocin treatment. This circumstance dictates the necessity to look for alternative ways of preventing the S. aureus carriage and methods of elimination. One of the methods of nasal S. aureus elimination is implantation of nonpathogenic microorganisms which will extrude opportunistic pathogens without impinging the symbiotic microbiota. Effectiveness of saline suspension of Corynebacterium pseudodiphtheriticum containing spray was assessed in a several chamber experiments with simulation of some spaceflight factors (dry immersion, isolation). Various schemes of application of preparations were applied. In all cases of corynebacteria application the strong inhibiting effect against S. aureus was detected. This fact opens a prospect of using nonpathogenic corynebacteria as a nasal probiotic. Administration of the nasal corynebacteria spray possibly prevented cross-infection by MRSA and appearance of staphylococcal infection. Further pre-clinical and clinical study of this bacterial therapy method is under development.

  3. Staphylococcus aureus: methicillin-susceptible S. aureus to methicillin-resistant S. aureus and vancomycin-resistant S. aureus.

    Science.gov (United States)

    Rehm, Susan J; Tice, Alan

    2010-09-15

    The evolution of methicillin-resistant and vancomycin-resistant Staphylococcus aureus has demanded serious review of antimicrobial use and development of new agents and revised approaches to prevent and overcome drug resistance. Depending on local conditions and patient risk factors, empirical therapy of suspected S. aureus infection may require coverage of drug-resistant organisms with newer agents and novel antibiotic combinations. The question of treatment with inappropriate antibiotics raises grave concerns with regard to methicillin-resistant S. aureus selection, overgrowth, and increased virulence. Several strategies to reduce the nosocomial burden of resistance are suggested, including shortened hospital stays and outpatient parenteral antimicrobial therapy of the most serious infections.

  4. Bacillithiol: a key protective thiol in Staphylococcus aureus.

    Science.gov (United States)

    Perera, Varahenage R; Newton, Gerald L; Pogliano, Kit

    2015-01-01

    Bacillithiol is a low-molecular-weight thiol analogous to glutathione and is found in several Firmicutes, including Staphylococcus aureus. Since its discovery in 2009, bacillithiol has been a topic of interest because it has been found to contribute to resistance during oxidative stress and detoxification of electrophiles, such as the antibiotic fosfomycin, in S. aureus. The rapid increase in resistance of methicillin-resistant Staphylococcus aureus (MRSA) to available therapeutic agents is a great health concern, and many research efforts are focused on identifying new drugs and targets to combat this organism. This review describes the discovery of bacillithiol, studies that have elucidated the physiological roles of this molecule in S. aureus and other Bacilli, and the contribution of bacillithiol to S. aureus fitness during pathogenesis. Additionally, the bacillithiol biosynthesis pathway is evaluated as a novel drug target that can be utilized in combination with existing therapies to treat S. aureus infections.

  5. Staphylococcus aureus and the ecology of the nasal microbiome

    DEFF Research Database (Denmark)

    Liu, Cindy M; Price, Lance B; Hungate, Bruce A

    2015-01-01

    The human microbiome can play a key role in host susceptibility to pathogens, including in the nasal cavity, a site favored by Staphylococcus aureus. However, what determines our resident nasal microbiota-the host or the environment-and can interactions among nasal bacteria determine S. aureus...

  6. The changing epidemiology of Staphylococcus aureus bloodstream infection

    DEFF Research Database (Denmark)

    Laupland, K B; Lyytikäinen, O; Søgaard, M;

    2012-01-01

    Clin Microbiol Infect ABSTRACT: Although the epidemiology of Staphylococcus aureus bloodstream infection (BSI) has been changing, international comparisons are lacking. We sought to determine the incidence of S. aureus BSI and assess trends over time and by region. Population-based surveillance...

  7. Pneumonia and new methicillin-resistant Staphylococcus aureus clone.

    NARCIS (Netherlands)

    Garnier, Fabien; Tristan, Anne; François, Bruno; Etienne, Jerome; Delage-Corre, Manuella; Martin, Christian; Liassine, Nadia; Wannet, Wim; Denis, François; Ploy, Marie-Cécile

    2006-01-01

    Necrotizing pneumonia caused by Staphylococcus aureus strains carrying the Panton-Valentin leukocidin gene is a newly described disease entity. We report a new fatal case of necrotizing pneumonia. An S. aureus strain with an agr1 allele and of a new sequence type 377 was recovered, representing a ne

  8. Intracellular Staphylococcus aureus : live-in and let die

    NARCIS (Netherlands)

    Fraunholz, Martin; Sinha, Bhanu

    2012-01-01

    Staphylococcus aureus uses a plethora of virulence factors to accommodate a diversity of niches in its human host. Aside from the classical manifestations of S. aureus-induced diseases, the pathogen also invades and survives within mammalian host cells. The survival strategies of the pathogen are as

  9. Structural features and kinetic characterization of alanine racemase from Staphylococcus aureus (Mu50).

    Science.gov (United States)

    Scaletti, Emma R; Luckner, Sylvia R; Krause, Kurt L

    2012-01-01

    Staphylococcus aureus is an opportunistic Gram-positive bacterium which causes a wide variety of diseases ranging from minor skin infections to potentially fatal conditions such as pneumonia, meningitis and septicaemia. The pathogen is a leading cause of nosocomial acquired infections, a problem that is exacerbated by the existence of methicillin- and glycopeptide antibiotic-resistant strains which can be challenging to treat. Alanine racemase (Alr) is a pyridoxal-5'-phosphate-dependent enzyme which catalyzes reversible racemization between enantiomers of alanine. As D-alanine is an essential component of the bacterial cell-wall peptidoglycan, inhibition of Alr is lethal to prokaryotes. Additionally, while ubiquitous amongst bacteria, this enzyme is absent in humans and most eukaryotes, making it an excellent antibiotic drug target. The crystal structure of S. aureus alanine racemase (Alr(Sas)), the sequence of which corresponds to that from the highly antibiotic-resistant Mu50 strain, has been solved to 2.15 Å resolution. Comparison of the Alr(Sas) structure with those of various alanine racemases demonstrates a conserved overall fold, with the enzyme sharing most similarity to those from other Gram-positive bacteria. Structural examination indicates that the active-site binding pocket, dimer interface and active-site entryway of the enzyme are potential targets for structure-aided inhibitor design. Kinetic constants were calculated in this study and are reported here. The potential for a disulfide bond in this structure is noted. This structural and biochemical information provides a template for future structure-based drug-development efforts targeting Alr(Sas).

  10. Antimicrobial Resistance of Escherichia coli, Enterococci, Pseudomonas aeruginosa, and Staphylococcus aureus from Raw Fish and Seafood Imported into Switzerland.

    Science.gov (United States)

    Boss, Renate; Overesch, Gudrun; Baumgartner, Andreas

    2016-07-01

    A total of 44 samples of salmon, pangasius (shark catfish), shrimps, and oysters were tested for the presence of Escherichia coli, enterococci, Pseudomonas aeruginosa, and Staphylococcus aureus, which are indicator organisms commonly used in programs to monitor antibiotic resistance. The isolated bacterial strains, confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectroscopy, were tested against a panel of 29 antimicrobial agents to obtain MICs. Across the four sample types, Enterococcus faecalis (59%) was most common, followed by E. coli (55%), P. aeruginosa (27%), and S. aureus (9%). All bacterial species were resistant to some antibiotics. The highest rates of resistance were in E. faecalis to tetracycline (16%), in E. coli to ciprofloxacin (22%), and in S. aureus to penicillin (56%). Antibiotic resistance was found among all sample types, but salmon and oysters were less burdened than were shrimps and pangasius. Multidrug-resistant (MDR) strains were exclusively found in shrimps and pangasius: 17% of pangasius samples (MDR E. coli and S. aureus) and 64% of shrimps (MDR E. coli, E. faecalis, and S. aureus). Two of these MDR E. coli isolates from shrimps (one from an organic sample) were resistant to seven antimicrobial agents. Based on these findings, E. coli in pangasius, shrimps, and oysters, E. faecalis in pangasius, shrimps, and salmon, and P. aeruginosa in pangasius and shrimps are potential candidates for programs monitoring antimicrobial resistance. Enrichment methods for the detection of MDR bacteria of special public health concern, such as methicillin-resistant S. aureus and E. coli producing extended-spectrum β-lactamases and carbapenemases, should be implemented.

  11. Propionibacterium acnes biofilm - A sanctuary for Staphylococcus aureus?

    Science.gov (United States)

    Tyner, Harmony; Patel, Robin

    2016-08-01

    The purpose of this study was to measure the effect of combined culture of Propionibacterium acnes and Staphylococcus aureus on biofilm formation under different oxygen concentrations. We measured planktonic growth and biofilm formation of P. acnes and S. aureus alone and together under aerobic and anaerobic conditions. Both P. acnes and S. aureus grew under anaerobic conditions. When grown under anaerobic conditions, P. acnes with or without S. aureus formed a denser biomass biofilm than did S. aureus alone. Viable S. aureus was recovered from a16-day old combined P. acnes and S. aureus biofilm, but not a monomicrobial S. aureus biofilm.

  12. Phagocytosis and Killing of Staphylococcus aureus by Human Neutrophils

    OpenAIRE

    Lu, Thea; Porter, Adeline R.; Kennedy, Adam D.; Kobayashi, Scott D.; Frank R DeLeo

    2014-01-01

    Neutrophils are essential for host defense against Staphylococcus aureus infections. Although significant progress has been made, our understanding of neutrophil interactions with S. aureus remains incomplete. To provide a more comprehensive view of this process, we investigated phagocytosis and killing of S. aureus by human neutrophils using varied assay conditions in vitro. A greater percentage of bacteria were internalized by adherent neutrophils compared to those in suspension, and unexpe...

  13. Combination of silver nanoparticles and Drosera binata extract as a possible alternative for antibiotic treatment of burn wound infections caused by resistant Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Marta Krychowiak

    Full Text Available Staphylococcus aureus is the most common infectious agent involved in the development of skin infections that are associated with antibiotic resistance, such as burn wounds. As drug resistance is a growing problem it is essential to establish novel antimicrobials. Currently, antibiotic resistance in bacteria is successfully controlled by multi-drug therapies. Here we demonstrate that secondary metabolites present in the extract obtained from Drosera binata in vitro cultures are effective antibacterial agents against S. aureus grown in planktonic culture and in biofilm. Moreover, this is the first report demonstrating the synergistic interaction between the D. binata extract and silver nanoparticles (AgNPs, which results in the spectacular enhancement of the observed bactericidal activity, while having no cytotoxic effects on human keratinocytes. Simultaneous use of these two agents in significantly reduced quantities produces the same effect, i.e. by killing 99.9% of bacteria in inoculum or eradicating the staphylococcal biofilm, as higher amounts of the agents used individually. Our data indicates that combining AgNPs with either the D. binata extract or with its pure compound (3-chloroplumbagin may provide a safe and highly effective alternative to commonly used antibiotics, which are ineffective towards the antibiotic-resistant S. aureus.

  14. Combination of Silver Nanoparticles and Drosera binata Extract as a Possible Alternative for Antibiotic Treatment of Burn Wound Infections Caused by Resistant Staphylococcus aureus

    Science.gov (United States)

    Krychowiak, Marta; Grinholc, Mariusz; Banasiuk, Rafal; Krauze-Baranowska, Miroslawa; Głód, Daniel; Kawiak, Anna; Królicka, Aleksandra

    2014-01-01

    Staphylococcus aureus is the most common infectious agent involved in the development of skin infections that are associated with antibiotic resistance, such as burn wounds. As drug resistance is a growing problem it is essential to establish novel antimicrobials. Currently, antibiotic resistance in bacteria is successfully controlled by multi-drug therapies. Here we demonstrate that secondary metabolites present in the extract obtained from Drosera binata in vitro cultures are effective antibacterial agents against S. aureus grown in planktonic culture and in biofilm. Moreover, this is the first report demonstrating the synergistic interaction between the D. binata extract and silver nanoparticles (AgNPs), which results in the spectacular enhancement of the observed bactericidal activity, while having no cytotoxic effects on human keratinocytes. Simultaneous use of these two agents in significantly reduced quantities produces the same effect, i.e. by killing 99.9% of bacteria in inoculum or eradicating the staphylococcal biofilm, as higher amounts of the agents used individually. Our data indicates that combining AgNPs with either the D. binata extract or with its pure compound (3-chloroplumbagin) may provide a safe and highly effective alternative to commonly used antibiotics, which are ineffective towards the antibiotic-resistant S. aureus. PMID:25551660

  15. Control of Staphylococcus aureus pathogenicity island excision.

    Science.gov (United States)

    Mir-Sanchis, Ignacio; Martínez-Rubio, Roser; Martí, Miguel; Chen, John; Lasa, Íñigo; Novick, Richard P; Tormo-Más, María Ángeles; Penadés, José R

    2012-09-01

    Staphylococcus aureus pathogenicity islands (SaPIs) are a group of related 15-17 kb mobile genetic elements that commonly carry genes for superantigen toxins and other virulence factors. The key feature of their mobility is the induction of SaPI excision and replication by certain phages and their efficient encapsidation into specific small-headed phage-like infectious particles. Previous work demonstrated that chromosomal integration depends on the SaPI-encoded recombinase, Int. However, although involved in the process, Int alone was not sufficient to mediate efficient SaPI excision from chromosomal sites, and we expected that SaPI excision would involve an Xis function, which could be encoded by a helper phage or by the SaPI, itself. Here we report that the latter is the case. In vivo recombination assays with plasmids in Escherichia coli demonstrate that SaPI-coded Xis is absolutely required for recombination between the SaPI att(L) and att(R) sites, and that both sites, as well as their flanking SaPI sequences, are required for SaPI excision. Mutational analysis reveals that Xis is essential for efficient horizontal SaPI transfer to a recipient strain. Finally, we show that the master regulator of the SaPI life cycle, Stl, blocks expression of int and xis by binding to inverted repeats present in the promoter region, thus controlling SaPI excision.

  16. High prevalence of class 1 integrons in clinical isolates of methicillin-resistant Staphylococcus aureus from India

    Directory of Open Access Journals (Sweden)

    N P Marathe

    2015-01-01

    Full Text Available Introduction: Class1 integrons are one of the prevalent mechanisms of antibiotic resistance gene transfer in Gram-negative organisms, but their prevalence and role in the spread of antibiotic resistance genes in methicillin-resistant Staphylococcus aureus (MRSA is unexplored. The purpose of this study was to investigate the prevalence of class 1 integrons in clinical isolates of MRSA. Materials and Methods: Total 143 MRSA isolates obtained from two different cities in India (Pune and Mumbai were characterized by biochemical tests, and the antibiotic sensitivity was performed using the Clinical and Laboratory Standards Institute (CLSI guidelines. The presence of class 1 integrons, sul1/qacE0Δ1 region of class 1 integron and mecA gene among these isolates was determined by polymerase chain reaction (PCR. Results: All 143 isolates were mecA positive and coagulase-positive. Overall, 71% of the MRSA isolates carried class 1 integrons; 58% (45/77 of the isolates obtained from Mumbai and 85% (56/66 of the isolates from Pune carried class 1 integrons. In all, 39% of these isolates carried sul1/qacEΔ1 region, thus confirming the association of class 1 integrons with antibiotic resistance genes. Along with β-lactam antibiotics the MRSA isolates were resistant to several other antibiotics, with resistance to erythromycin, ciprofloxacin and trimethoprim-sulfamethoxazole being observed in 75%, 66% and 60% of the isolates, respectively. Conclusion: To the best of our knowledge, this is the first report of class 1 integrons in MRSA isolates from India. The study provides insights into the prevalence of a novel mechanism adapted by MRSA for the propagation of antibiotic resistance genes.

  17. Virulence Factors and Antibiotic Susceptibility of Staphylococcus aureus Isolates in Ready-to-Eat Foods: Detection of S. aureus Contamination and a High Prevalence of Virulence Genes

    Directory of Open Access Journals (Sweden)

    Suat Moi Puah

    2016-02-01

    Full Text Available Staphylococcus aureus is one of the leading causes of food poisoning. Its pathogenicity results from the possession of virulence genes that produce different toxins which result in self-limiting to severe illness often requiring hospitalization. In this study of 200 sushi and sashimi samples, S. aureus contamination was confirmed in 26% of the food samples. The S. aureus isolates were further characterized for virulence genes and antibiotic susceptibility. A high incidence of virulence genes was identified in 96.2% of the isolates and 20 different virulence gene profiles were confirmed. DNA amplification showed that 30.8% (16/52 of the S. aureus carried at least one SE gene which causes staphylococcal food poisoning. The most common enterotoxin gene was seg (11.5% and the egc cluster was detected in 5.8% of the isolates. A combination of hla and hld was the most prevalent coexistence virulence genes and accounted for 59.6% of all isolates. Antibiotic resistance studies showed tetracycline resistance to be the most common at 28.8% while multi-drug resistance was found to be low at 3.8%. In conclusion, the high rate of S. aureus in the sampled sushi and sashimi indicates the need for food safety guidelines.

  18. Vaccination with a recombinant fragment of collagen adhesin provides protection against Staphylococcus aureus-mediated septic death.

    Science.gov (United States)

    Nilsson, I M; Patti, J M; Bremell, T; Höök, M; Tarkowski, A

    1998-06-15

    Staphylococcus aureus is a major cause of nosocomial and community-acquired infections. Morbidity and mortality due to infections such as sepsis, osteomyelitis, septic arthritis, and invasive endocarditis remain high despite the use of antibiotics. The emergence of antibiotic resistant super bugs mandates that alternative strategies for the prevention and treatment of S. aureus infections are developed. We investigated the ability of vaccination with a recombinant fragment of the S. aureus collagen adhesin to protect mice against sepsis-induced death. Actively immunized NMRI mice were intravenously inoculated with the S. aureus clinical isolate strain Phillips. 14 d after inoculation, mortality in the collagen adhesin-vaccinated group was only 13%, compared with 87% in the control antigen immunized group (P < 0.001). To determine if the protective effect was antibody mediated, we passively immunized naive mice with collagen adhesin-specific antibodies. Similar to the active immunization strategy, passive transfer of collagen adhesin-specific antibodies protected mice against sepsis-induced death. In vitro experiments indicated that S. aureus opsonized with sera from collagen adhesin immunized mice promoted phagocytic uptake and enhanced intracellular killing compared with bacteria opsonized with sera from control animals. These results indicate that the collagen adhesin is a viable target in the development of immunotherapeutics against S. aureus.

  19. One-year mortality in coagulase-negative Staphylococcus and Staphylococcus aureus infective endocarditis

    DEFF Research Database (Denmark)

    Rasmussen, Rasmus V; Snygg-Martin, Ulrika; Olaison, Lars;

    2009-01-01

    The aim of this study was to investigate in-hospital mortality and 12-month mortality in patients with coagulase-negative Staphylococcus (CoNS) compared to Staphylococcus aureus (S. aureus) infective endocarditis (IE). We used a prospective cohort study of 66 consecutive CoNS and 170 S. aureus IE...... patients, collected at 2 tertiary university hospitals in Copenhagen (Denmark) and at 1 tertiary university hospital in Gothenburg (Sweden). Median (range) C-reactive protein at admission was higher in patients with S. aureus IE (150 mg/l (1-521) vs 94 mg/l (6-303); p

  20. Antimicrobial drug resistance ofStaphylococcus aureus in dairy products

    Institute of Scientific and Technical Information of China (English)

    Sasidharan S; Prema B; Yoga Latha L

    2011-01-01

    Objective:To evaluate the prevalence of multidrug resistantStaphylococcus aureus(S. aureus) in dairy products.Methods:Isolation and identification ofS. aureus were performed in3 dairy-based food products. The isolates were tested for their susceptibility to5 different common antimicrobial drugs.Results:Of50 samples examined,5 (10%) were contaminated with S. aureus. Subsequently, the5 isolates were subjected to antimicrobial resistance pattern using five antibiotic discs (methicillin, vancomycin, kanamycin, chloramphenicol and tetracycline). Sample 29 showed resistance to methicillin and vancomycin. Sample18 showed intermediate response to tetracycline. The other samples were susceptible to all the antibiotics tested.Conclusions:The results provide preliminary data on sources of food contamination which may act as vehicles for the transmission of antimicrobial-resistantStaphylococcus.Therefore, it enables us to develop preventive strategies to avoid the emergence of new strains of resistantS. aureus.

  1. Resistance in Staphylococcus Aureus: The Never-Ending Story

    Directory of Open Access Journals (Sweden)

    Orlović Jovan

    2016-09-01

    Full Text Available Combating Staphylococcus aureus (S. aureus infections using antibacterial drugs is actually an ongoing effort to overcome resistance mechanism of this microorganism. In this paper, we discussed (1 the mechanisms of resistance to some of the most commonly used antimicrobial agents in the treatment of S. aureus: methicillin, vancomicyn and quinolones. In addition, (2 efflux pump mechanisms involved in maintaining homeostasis in the presence of compounds that inhibit S. aureus growth and reproduction, as well as mechanisms of resistance to a number of antibiotics, have been reviewed.

  2. Prevention of Healthcare Associated Staphylococcus aureus Infections

    NARCIS (Netherlands)

    L.G.M. Bode (Lonneke)

    2014-01-01

    markdownabstract__Abstract__ S. aureus colonizes the skin and mucosae of a proportion of the human population. Carriers of S. aureus are at increased risk of developing infections with this pathogen. The aim of this thesis was to add to the prevention of healthcare associated S. aureus infections.

  3. Antibodies to Staphylococcus aureus capsular polysaccharides 5 and 8 perform similarly in vitro but are functionally distinct in vivo.

    Science.gov (United States)

    Liu, Bo; Park, Saeyoung; Thompson, Christopher D; Li, Xue; Lee, Jean C

    2016-12-09

    The capsular polysaccharide (CP) produced by Staphylococcus aureus is a virulence factor that allows the organism to evade uptake and killing by host neutrophils. Polyclonal antibodies to the serotype 5 (CP5) and type 8 (CP8) capsular polysaccharides are opsonic and protect mice against experimental bacteremia provoked by encapsulated staphylococci. Thus, passive immunotherapy using CP antibodies has been considered for the prevention or treatment of invasive antibiotic-resistant S. aureus infections. In this report, we generated monoclonal antibodies (mAbs) against S. aureus CP5 or CP8. Backbone specific mAbs reacted with native and O-deacetylated CPs, whereas O-acetyl specific mAbs reacted only with native CPs. Reference strains of S. aureus and a selection of clinical isolates reacted by colony immunoblot with the CP5 and CP8 mAbs in a serotype-specific manner. The mAbs mediated in vitro CP type-specific opsonophagocytic killing of S. aureus strains, and mice passively immunized with CP5 mAbs were protected against S. aureus bacteremia. Neither CP8-specific mAbs or polyclonal antibodies protected mice against bacteremia provoked by serotype 8 S. aureus clinical isolates, although these same antibodies did protect against a serotype 5 S. aureus strain genetically engineered to produce CP8. We detected soluble CP8 in culture supernatants of serotype 8 clinical isolates and in the plasma of infected animals. Serotype 5 S. aureus released significantly less soluble CP5 in vitro and in vivo. The release of soluble CP8 by S. aureus may contribute to the inability of CP8 vaccines or antibodies to protect against serotype 8 staphylococcal infections.

  4. Inhibition of β-lactamase-mediated oxacillin resistance in Staphylococcus aureus by a deoxyribozyme

    Institute of Scientific and Technical Information of China (English)

    Zheng HOU; Jing-ru MENG; Jin-rong ZHAO; Ben-quan HU; Jie LIU; Xiao-jun YAN; Min JIA; Xiao-xing LUO

    2007-01-01

    Aim:To investigate the oxacillin susceptibility restoration of methicillin-resistant Staphylococcus aureus (MRSA) by targeting the signaling pathway of blaR1blaZ with a DNAzyme. Methods:A DNAzyme (named PS-DP,z602) targeting blaR1 mRNA was designed and synthesized. After DRz602 was introduced into a MRSA strain WHO-2,the colony-forming units of WHO-2 on the Mueller-Hinton agar containing 6 mg/L oxacillin and the minimum inhibitory concentrations of oxacillin were determined. The inhibitory effects of DRz602 on the expressions of antibiotic-resistant gene blaR1 and its downstream gene blaZ were detected by real time RT-PCR. Results:PS-DRz602 significantly decreased the transcription of blaR1 mRNA and led to the significant reduction of blaZ in a concentrationdependent manner. Consequently,the resistance of S aureus WHO-2 to the β-lactam antibiotic oxacillin was significantly inhibited. Conclusion:Our results indicated that blocking the blaRl-blaZ signaling pathway via DNAzyme might provide a viable strategy for inhibiting the resistance of MRSA to β-lactam antibiotics and that BIaR1 might be a potential target for pharmacological agents combating MRSA.

  5. Comparison of antibiotic resistance, biofilm formation and conjugative transfer of Staphylococcus and Enterococcus isolates from International Space Station and Antarctic Research Station Concordia.

    Science.gov (United States)

    Schiwon, Katarzyna; Arends, Karsten; Rogowski, Katja Marie; Fürch, Svea; Prescha, Katrin; Sakinc, Türkan; Van Houdt, Rob; Werner, Guido; Grohmann, Elisabeth

    2013-04-01

    The International Space Station (ISS) and the Antarctic Research Station Concordia are confined and isolated habitats in extreme and hostile environments. The human and habitat microflora can alter due to the special environmental conditions resulting in microbial contamination and health risk for the crew. In this study, 29 isolates from the ISS and 55 from the Antarctic Research Station Concordia belonging to the genera Staphylococcus and Enterococcus were investigated. Resistance to one or more antibiotics was detected in 75.8 % of the ISS and in 43.6 % of the Concordia strains. The corresponding resistance genes were identified by polymerase chain reaction in 86 % of the resistant ISS strains and in 18.2 % of the resistant Concordia strains. Plasmids are present in 86.2 % of the ISS and in 78.2 % of the Concordia strains. Eight Enterococcus faecalis strains (ISS) harbor plasmids of about 130 kb. Relaxase and/or transfer genes encoded on plasmids from gram-positive bacteria like pIP501, pRE25, pSK41, pGO1 and pT181 were detected in 86.2 % of the ISS and in 52.7 % of the Concordia strains. Most pSK41-homologous transfer genes were detected in ISS isolates belonging to coagulase-negative staphylococci. We demonstrated through mating experiments that Staphylococcus haemolyticus F2 (ISS) and the Concordia strain Staphylococcus hominis subsp. hominis G2 can transfer resistance genes to E. faecalis and Staphylococcus aureus, respectively. Biofilm formation was observed in 83 % of the ISS and in 92.7 % of the Concordia strains. In conclusion, the ISS isolates were shown to encode more resistance genes and possess a higher gene transfer capacity due to the presence of three vir signature genes, virB1, virB4 and virD4 than the Concordia isolates.

  6. Comparative genomic analysis of the genus Staphylococcus including Staphylococcus aureus and its newly described sister species Staphylococcus simiae

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    Suzuki Haruo

    2012-01-01

    Full Text Available Abstract Background Staphylococcus belongs to the Gram-positive low G + C content group of the Firmicutes division of bacteria. Staphylococcus aureus is an important human and veterinary pathogen that causes a broad spectrum of diseases, and has developed important multidrug resistant forms such as methicillin-resistant S. aureus (MRSA. Staphylococcus simiae was isolated from South American squirrel monkeys in 2000, and is a coagulase-negative bacterium, closely related, and possibly the sister group, to S. aureus. Comparative genomic analyses of closely related bacteria with different phenotypes can provide information relevant to understanding adaptation to host environment and mechanisms of pathogenicity. Results We determined a Roche/454 draft genome sequence for S. simiae and included it in comparative genomic analyses with 11 other Staphylococcus species including S. aureus. A genome based phylogeny of the genus confirms that S. simiae is the sister group to S. aureus and indicates that the most basal Staphylococcus lineage is Staphylococcus pseudintermedius, followed by Staphylococcus carnosus. Given the primary niche of these two latter taxa, compared to the other species in the genus, this phylogeny suggests that human adaptation evolved after the split of S. carnosus. The two coagulase-positive species (S. aureus and S. pseudintermedius are not phylogenetically closest but share many virulence factors exclusively, suggesting that these genes were acquired by horizontal transfer. Enrichment in genes related to mobile elements such as prophage in S. aureus relative to S. simiae suggests that pathogenesis in the S. aureus group has developed by gene gain through horizontal transfer, after the split of S. aureus and S. simiae from their common ancestor. Conclusions Comparative genomic analyses across 12 Staphylococcus species provide hypotheses about lineages in which human adaptation has taken place and contributions of horizontal

  7. Resistencia antimicrobiana de cepas de Staphylococcus aureus, Costa Rica Antimicrobial resistance of Staphylococcus aureus, Costa Rica

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    Víctor Hugo Alvarado

    2011-12-01

    Full Text Available Objetivo: Determinar y comparar los perfiles de resistencia de cepas de S. aureus aisladas de quesos, producidos en la Zona Sur de Costa Rica y de un centro hospitalario de la misma región. Materiales y Métodos: Se analizaron 35 muestras de queso fresco, adquiridas durante los meses de setiembre y octubre del 2010 en la zona de San Vito de Coto Brus. A cada muestra se le realizaron recuentos de coliformes totales, coliformes fecales y Staphylococcus aureus. Adicionalmente se analizó presencia/ausencia de Listeria monocytogenes en 25 gramos del producto. A las cepas identificadas como S. aureus se les realizó la prueba de sensibilidad a los antibióticos mediante el sistema automatizado Vitek y la interpretación de los datos se realizó siguiendo las pautas del Clinical and Laboratory Standards Institute antimicrobial susceptibility testing 2011. Adicional a esto se recolectaron datos acerca de la sensibilidad de las cepas de S. aureus aisladas e identificadas en el Hospital de San Vito de Coto Brus en el mismo período. Resultados: El promedio obtenido para el recuento de coliformes totales fue de 9,7 X 10(6 UFC/g, para coliformes fecales de 6,7 X 10(5 y para S. aureus de 2,8 X 10(5 UFC/g, obteniéndose un 83 % de muestras positivas por esta bacteria. En cuanto a la resistencia antimicrobiana, se obtuvieron porcentajes de resistencia mayores en las cepas de origen clínico. Se encontró también que 23 de las cepas (96% provenientes de muestras clínicas, presentaban resistencia a más de un antibiótico, mientras que siete de las obtenidas a partir de queso (27% presentaban esta característica. Con respecto a los betalactamicos (ampicilina, oxacilina y penicilina se observó la existencia de una diferencia estadísticamente significativa (pObjective: determined and compared the resistance patters of S. aureus strains isolated from cheese produced in the southern zone of Costa Rica and from clinical samples isolated at the hospital center

  8. Detection of methicillin-resistant Staphylococcus aureus using phage amplification combined with matrix-assisted laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Rees, Jon C; Barr, John R

    2017-02-01

    Antibiotic resistance continues to contribute significantly to morbidity and mortality across the world. Developing new tests for antibiotic-resistant bacteria is a core action to combat resistant infections. We describe a method that uses phage amplification detection (PAD) combined with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) to rapidly identify Staphylococcus aureus and determine phenotypic susceptibility to cefoxitin. Samples tested for S. aureus are incubated together with bacteriophage in the presence and absence of cefoxitin and subjected to rapid trypsin digestion followed by MALDI-MS analysis. Tryptic peptides derived from amplified phage proteins can be detected by MALDI-MS, as validated by time-of-flight (TOF)/TOF analysis of each peptide combined with database searching. Methicillin-resistant S. aureus show significant phage amplification in the presence of cefoxitin, while methicillin-sensitive S. aureus show no phage amplification relative to a no-antibiotic control. We also show that PAD methodology can be implemented on an FDA-approved commercial MALDI-MS bacterial identification system to identify S. aureus and determine antibiotic susceptibility. The novelty of this assay includes the use of phage-derived tryptic peptides as detected by MALDI-MS to monitor the results of PAD on an instrument common to many modern microbiology laboratories.

  9. Prevalence of Staphylococcus aureus and Staphylococcus saprophyticus in Imam Khomayni Hospital, Ilam, 2011-2012

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    Reza Azizian

    2014-01-01

    Full Text Available Abstract Background and objective: Staphylococcus aureus is one of the main causes of hospital infections. Staphylococcus saprophyticus is a common agent of urinary tract infections. Hospital acquired infection as an old challenge has high importance in hospital infection control and Staphylococcus spp. play main role among routine pathogens. this study designed to investigate the of Staphylococcus aureus and Staphylococcus saprophyticus among ICU, Men and Children wards. Materials and methods: Samples collected randomly from ICU, Men and Children wards. Through 203 sampling of wall, floor, bed, pillow and blanket, 75 Staphylococcus spp. isolated. Species recognizes base on culture on Mannitol salt agar and Novobiocin susceptibility determination. Result: Among 75 positive samples, 62 (82.7%, and 13 isolates were Staphylococcus saprophyticus, Staphylococcus aureus, respectively. 51% of bacteria isolated from ICU, 29% from children ward and 20% from men surgery ward. Staphylococcus saprophyticus comprised 87%, 82% and 73% of isolates pertaining to ICU, pediatric and men surgery wards, in a row. Conclusion: Our funding indicate there is an inappropriate instrument to deal with infection in hospital specially ICU. Regards to this issue that Staphylococcus spp. as a main pathogen which has potency to form biofilm and show high resistance to extended broad antibiotics therefore it is suggested to prepare proper guideline to cope with bacteria dissemination and resistance emergence in hospital.

  10. Small changes in environmental parameters lead to alterations in antibiotic resistance, cell morphology and membrane fatty acid composition in Staphylococcus lugdunensis.

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    Marcus J Crompton

    Full Text Available Staphylococcus lugdunensis has emerged as a major cause of community-acquired and nosocomial infections. This bacterium can rapidly adapt to changing environmental conditions to survive and capitalize on opportunities to colonize and infect through wound surfaces. It was proposed that S. lugdunensis would have underlying alterations in metabolic homeostasis to provide the necessary levels of adaptive protection. The aims of this project were to examine the impacts of subtle variations in environmental conditions on growth characteristics, cell size and membrane fatty acid composition in S. lugdunensis. Liquid broth cultures of S. lugdunensis were grown under varying combinations of pH (6-8, temperature (35-39°C and osmotic pressure (0-5% sodium chloride w/w to reflect potential ranges of conditions encountered during transition from skin surfaces to invasion of wound sites. The cells were harvested at the mid-exponential phase of growth and assessed for antibiotic minimal inhibitory concentration (MIC, generation time, formation of small colony variants, cell size (by scanning electron microscopy and membrane fatty acid composition. Stress regimes with elevated NaCl concentrations resulted in significantly higher antibiotic resistance (MIC and three of the combinations with 5% NaCl had increased generation times (P<0.05. It was found that all ten experimental growth regimes, including the control and centroid cultures, yielded significantly different profiles of plasma membrane fatty acid composition (P<0.0001. Alterations in cell size (P<0.01 were also observed under the range of conditions with the most substantial reduction occurring when cells were grown at 39°C, pH 8 (514±52 nm, mean ± Standard Deviation compared with cells grown under control conditions at 37°C with pH 7 (702±76 nm, P<0.01. It was concluded that S. lugdunensis responded to slight changes in environmental conditions by altering plasma membrane fatty acid composition

  11. Botryomycosis Due to Staphylococcus Aureus-A Case Report

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    Manjula A.Vagarali

    2012-04-01

    Full Text Available Objectives: To study Staphylococcus aureus as the causative organism of botryomycosis. Background: the botryomycosis is a chronic purulent granulomatous lesion of the skin, subcutaneous tissue and visceral organs caused by several bacterial species. This condition clinically and histopathologically resembles with that of mycetoma and Actinomycosis. Method: A 51 year old male presented to us with swelling over medial aspect of the right foot with multiple sinuses. He gave a history of trauma 3 years back at the same site. The sample was examined directly by KOH preparation and grams stain. The culture was put up on blood, chocolate, lowenstein Jensen (LJ and sabouraud dextrose agar (SDA media. Fungal culture was negative. Result: Staphylococcus aureus was isolated in aerobic culture. Conclusion: the patient with botryomycosis caused by Staphylococcus aureus was subsequently treated with antibiotics and he recovered completely.

  12. Contribution of the nos-pdt operon to virulence phenotypes in methicillin-sensitive Staphylococcus aureus.

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    April M Sapp

    Full Text Available Nitric oxide (NO is emerging as an important regulator of bacterial stress resistance, biofilm development, and virulence. One potential source of endogenous NO production in the pathogen Staphylococcus aureus is its NO-synthase (saNOS enzyme, encoded by the nos gene. Although a role for saNOS in oxidative stress resistance, antibiotic resistance, and virulence has been recently-described, insights into the regulation of nos expression and saNOS enzyme activity remain elusive. To this end, transcriptional analysis of the nos gene in S. aureus strain UAMS-1 was performed, which revealed that nos expression increases during low-oxygen growth and is growth-phase dependent. Furthermore, nos is co-transcribed with a downstream gene, designated pdt, which encodes a prephenate dehydratase (PDT enzyme involved in phenylalanine biosynthesis. Deletion of pdt significantly impaired the ability of UAMS-1 to grow in chemically-defined media lacking phenylalanine, confirming the function of this enzyme. Bioinformatics analysis revealed that the operon organization of nos-pdt appears to be unique to the staphylococci. As described for other S. aureus nos mutants, inactivation of nos in UAMS-1 conferred sensitivity to oxidative stress, while deletion of pdt did not affect this phenotype. The nos mutant also displayed reduced virulence in a murine sepsis infection model, and increased carotenoid pigmentation when cultured on agar plates, both previously-undescribed nos mutant phenotypes. Utilizing the fluorescent stain 4-Amino-5-Methylamino-2',7'-Difluorofluorescein (DAF-FM diacetate, decreased levels of intracellular NO/reactive nitrogen species (RNS were detected in the nos mutant on agar plates. These results reinforce the important role of saNOS in S. aureus physiology and virulence, and have identified an in vitro growth condition under which saNOS activity appears to be upregulated. However, the significance of the operon organization of nos-pdt and

  13. Incidenza della meticillino-resistenza in Staphylococcus aureus e stafilococchi coagulasi-negativi isolati da emocolture

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    Alessandra Siddi

    2007-12-01

    Full Text Available Background: Staphylococci are major cause of nosocomial blood stream infections.This local surveillance study was carry out to monitor frequency of occurrence of Staphylococcus aureus and coagulase-negative staphylococci (CoNS in blood stream infections and the incidence of methicillin-resistant (MET-R strains. Materials and methods: During the period January – December 2006, 9840 blood specimens were analyzed and microrganisms from positive samples were collected. Bacterial identifications were performed according to the standard methods (Murray, 2003.We evaluated, in particular, the antibiotic-resistance phenotype of staphylococci employing disk diffusion test as suggested by the CLSI (2006. The following antimicrobial agents were tested: oxacillin, penicillin, amoxiciclin-clavulanate, cefalotin, cefamandole, imipenem, teicoplanin, linezolid, ciprofloxacin, erythromycin, clindamicin, rifampicin, trimethoprim-sulfamethoxazole, gentamicin, doxiciclin, fosfomycin. Results: The microrganisms isolated were 551: 370 Gram-positives (67%, 131 Gram-negatives (24%, 11 anaerobes (2% and 39 mycetes (7%. In particular, 121 S. epidermidis, 75 S. aureus, 42 S. haemolyticus and other 39 CoNS were analyzed: methicillin-resistance occurred in more than 80% of S.aureus strains collected from Intensive Care Units (ICU and in about 50 % of those isolated from other divisions. In CoNS the incidence of MET-R ranged from 30 to 80 %, the higher values were registered among S. epidermidis and S. haemolyticus. MET-R strains were characterized by high resistance rates even to ciprofloxacin (from 47 to 100%, erythromycin (from 70 to 100%, and in same cases to gentamicin (from 23 to 86% also. Conclusions: Staphylococci are the prevalent cause of blood stream infections.The distinctive feature of MET-R strains is their resistance not only to all b-lactam antibiotics, but also to a wide range of other antimicrobial agents. However, the glycopeptide teicoplanin remains 100

  14. Molecular characterization of methicillin resistant Staphylococcus aureus isolated from hospitals environments and patients in Northern Palestine

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    Ghaleb Adwan

    2015-09-01

    Full Text Available BACKGROUND: Staphylococcus aureus (S. aureus is considered one of the most common pathogen to humans. Infections caused by this mocroorganism can be acquired through both hospital and community settings. This study was carried out to investigate molecular characterization of MRSA strains isolated from the patients and their environment in two hospitals (Rafidia hospital and Thabet hospital inNorthern Palestine, and to determine the clonal identity between these strains and their possible contribution to nosocomial infections.METHODS: Two hundred sixty five swabbed samples were collected from these hospitals, S. aureus was isolated,  antibiotic resistant genes were Panton–Valentin leukocidin (PVL gene were detected and SCCmec and spA were typed by PCR and/or sequencing.RESULTS: The prevalence of MRSA among S. aureus isolates was 29% and 8.2% in Rafidia hospital and Thabet hospital, respectively. All strains resistant to oxacilllin disk were carried mecA gene. Majority of strains (84.6% carried SCCmec type II (n = 11, type IVa and non-typeable were also detected. In addition, PVL was detected in 2 (14.3% clinical strains. ERIC PCR patterns revealed that 2 strains recovered from patient bed and nasal swab isolated from Thabet Hospital were nontypeable, spA typing showed that they belonged to type t386 and have identical DNA sequences. Other 2 clinical isolates were spa typed, one belonged to clone t044, while the other is new clone not exist in database.CONCLUSIONS: Results may give evidence that environmental contamination possibly contributing to nosocomial infections.

  15. The evolution of vancomycin intermediate Staphylococcus aureus (VISA) and heterogenous-VISA.

    Science.gov (United States)

    Howden, Benjamin P; Peleg, Anton Y; Stinear, Timothy P

    2014-01-01

    Resistance to new antimicrobials is generally recognized in Staphylococcus aureus soon after they are released for clinical use. In the case of vancomycin, which was first released in the 1950s, resistance was not reported until the mid 1990s, with the description of vancomycin-intermediate S. aureus (VISA), and heterogenous-VISA (hVISA). Unraveling the complex genetic and cell wall structural changes conferring low-level vancomycin resistance in S. aureus has proved challenging. However the recent advances in high throughput whole-genome sequencing has played a key role in determining the breadth of bacterial chromosomal changes linked with resistance. Diverse mutations in a small number of staphylococcal regulatory genes, in particular walKR, graRS, vraSR and rpoB, have been associated with hVISA and VISA. Only a small number of these mutations have been experimentally proven to confer the resistance phenotype and some of these only partially contribute to resistance. It also appears that the evolution of VISA from VSSA is a step-wise process. Transcriptomics studies, and analysis of host pathogen interactions, indicate that the evolution of vancomycin-susceptible S. aureus to VISA is associated not only with antibiotic resistance, but with other changes likely to promote persistent infection. These include predicted alterations in central metabolism, altered expression of virulence associated factors, attenuated virulence in vivo, and alterations in susceptibility to host innate immune responses, together with reduced susceptibility to other antibiotics. In fact, current data suggests that hVISA and VISA represent a bacterial evolutionary state favoring persistence in the face of not only antibiotics, but also the host environment. The additional knowledge of staphylococcal biology that has been uncovered during the study of hVISA and VISA is significant. The present review will detail the current understanding of the evolutionary process in the generation of h

  16. Quality control of direct molecular diagnostics for methicillin-resistant Staphylococcus aureus.

    NARCIS (Netherlands)

    A.F. van Belkum (Alex); H.G.M. Niesters (Bert); W.G. MacKay (William); W.B. van Leeuwen (Willem)

    2007-01-01

    textabstractTen samples containing various amounts of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus, methicillin-resistant Staphylococcus epidermidis (MRSE), and combinations thereof were distributed to 51 laboratories for molecular diagnostics testing. Sample

  17. Quality control of direct molecular diagnostics for methicillin-resistant Staphylococcus aureus

    NARCIS (Netherlands)

    van Belkum, Alex; Niesters, Hubert G M; MacKay, William G; van Leeuwen, Willem B

    2007-01-01

    Ten samples containing various amounts of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus, methicillin-resistant Staphylococcus epidermidis (MRSE), and combinations thereof were distributed to 51 laboratories for molecular diagnostics testing. Samples containing

  18. Simultaneous Identification and Susceptibility Determination to Multiple Antibiotics of Staphylococcus aureus by Bacteriophage Amplification Detection Combined with Mass Spectrometry.

    Science.gov (United States)

    Rees, Jon C; Pierce, Carrie L; Schieltz, David M; Barr, John R

    2015-07-01

    The continued advance of antibiotic resistance in clinically relevant bacterial strains necessitates the development and refinement of assays that can rapidly and cost-effectively identify bacteria and determine their susceptibility to a panel of antibiotics. A methodology is described herein that exploits the specificity and physiology of the Staphylococci bacteriophage K to identify Staphylococcus aureus (S. aureus) and determine its susceptibility to clindamycin and cefoxitin. The method uses liquid chromatography-mass spectrometry to monitor the replication of bacteriophage after it is used to infect samples thought to contain S. aureus. Amplification of bacteriophage K indicates the sample contains S. aureus, for it is only in the presence of a suitable host that bacteriophage K can amplify. If bacteriophage amplification is detected in samples containing the antibiotics clindamycin or cefoxitin, the sample is deemed to be resistant to these antibiotics, respectively, for bacteriophage can only amplify in a viable host. Thus, with a single work flow, S. aureus can be detected in an unknown sample and susceptibility to clindamycin and cefoxitin can be ascertained. This Article discusses implications for the use of bacteriophage amplification in the clinical laboratory.

  19. The screening of Staphylococcus with reduced susceptibility to vancomycin and the detection of the clinically relevant antibiotic resistant genes%万古霉素敏感性减低葡萄球菌筛选及抗生素耐药相关基因检测

    Institute of Scientific and Technical Information of China (English)

    茅挺; 王敬华; 邹静雯

    2011-01-01

    Objective To determine the existence of the clinically relevant antibiotic resistant genes in clinical isolates of Staphylococcus with reduced susceptibility to vancomycin.Methods 100 stains of clinical isolates staphylococci were subjected to Brain Heart Infusion (BHI) vancomycin screen agar to screen vancomycin intermediate Staphylococcus or vancomycin resistant Staphylococcus, and then performed population analysis to detect heterogeneous vancomycin-resistant staphylococci (hVRS).MICs of the staphylococci with reduced susceptibility to vancomycin were detected by E-test and by Mueller-Hinton agar Micro-dilution; Antibiotic resistant genes including mecaA, aac(6’)/aph(2″) aph(3’)-Ⅲ, tetM, vanA, vanB and vanC were detected by PCR, and PCR products were sequenced.Results No vancomycin intermediate or resistant Staphylococcus was detected, but 7 strains of heterogeneous vancomycin-resistant staphylococci were isolated; the detective rates of mecaA and aph(3’)-Ⅲ were both 85.7%, but 57.1% for aac(6’)/aph(2″); no vanA, vanB, vanC or terM gene was detected from hVRS by PCR.Conclusions It is similar to methicillin resistant Staphylococcus aureus that heterogeneous vancomycin-resistant staphylococci carry many clinically relevant antibiotic resistant genes and resistant to most of antibiotics.So, furtherstudy of the antibiotics resistance mechanism of Staphylococcus with reduced susceptibility to vancomycin should be kept focus on.%目的 了解万古霉素敏感性减低葡萄球菌临床分离株对-内酰胺类、氨基糖苷类、四环素以及万古霉素耐药相关基因存在状况.方法 采用含61tg/mL万古霉素脑心浸液琼脂从临床分离的葡萄球菌中筛选万古霉素中介葡萄球菌和万古霉素耐药葡萄球菌;采用菌谱分析法筛选异质性万古霉素耐药葡萄球菌:E-test法和琼脂稀释法检测其MIC值;PCR技术扩增mecA,aac(6')/aph(2'),aph(3)-Ⅲ,tetM,vanA.vanB和vanC基因,并对阳性

  20. METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS STRAINS IN FOOD AND ANIMAL

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    A. Traversa

    2010-03-01

    Full Text Available Some authors reported the possibility of a methicillin-resistant Staphylococcus aureus (MRSA human infections from meat and dairy products and methicillin-resistant Staphylococcus intermedius isolation in animals. The aim of this study is to investigate the methicillin-resistance in S. aureus strains and in S. intermedius strains (food and wild animals. 236 S.aureus strains from food, 36 S.aureus strains and 1 S. intermedius strain from wild animals were analyzed. 2 (0.74% MRSA strains from bovine milk were phenotipically resistant to cefoxitin, grew on chromogenic medium (MRSA Brilliance Oxoid and were mecA positive. All MRSA strains had the spa-type t899. All mecA positive strains showed at least resistance to eight of the antibiotics tested but none to glicopeptides. Both MRSA strains were enterotoxigenic.

  1. Sequence diversities of serine-aspartate repeat genes among Staphylococcus aureus isolates from different hosts presumably by horizontal gene transfer.

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    Huping Xue

    Full Text Available BACKGROUND: Horizontal gene transfer (HGT is recognized as one of the major forces for bacterial genome evolution. Many clinically important bacteria may acquire virulence factors and antibiotic resistance through HGT. The comparative genomic analysis has become an important tool for identifying HGT in emerging pathogens. In this study, the Serine-Aspartate Repeat (Sdr family has been compared among different sources of Staphylococcus aureus (S. aureus to discover sequence diversities within their genomes. METHODOLOGY/PRINCIPAL FINDINGS: Four sdr genes were analyzed for 21 different S. aureus strains and 218 mastitis-associated S. aureus isolates from Canada. Comparative genomic analyses revealed that S. aureus strains from bovine mastitis (RF122 and mastitis isolates in this study, ovine mastitis (ED133, pig (ST398, chicken (ED98, and human methicillin-resistant S. aureus (MRSA (TCH130, MRSA252, Mu3, Mu50, N315, 04-02981, JH1 and JH9 were highly associated with one another, presumably due to HGT. In addition, several types of insertion and deletion were found in sdr genes of many isolates. A new insertion sequence was found in mastitis isolates, which was presumably responsible for the HGT of sdrC gene among different strains. Moreover, the sdr genes could be used to type S. aureus. Regional difference of sdr genes distribution was also indicated among the tested S. aureus isolates. Finally, certain associations were found between sdr genes and subclinical or clinical mastitis isolates. CONCLUSIONS: Certain sdr gene sequences were shared in S. aureus strains and isolates from different species presumably due to HGT. Our results also suggest that the distributional assay of virulence factors should detect the full sequences or full functional regions of these factors. The traditional assay using short conserved regions may not be accurate or credible. These findings have important implications with regard to animal husbandry practices that may

  2. Antibiotic-specific differences in the response of Staphylococcus aureus to treatment with antimicrobials combined with manuka honey

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    Michael eLiu

    2015-01-01

    Full Text Available Skin infections caused by antibiotic resistant Staphylococcus aureus are a significant health problem worldwide; often associated with high treatment cost and mortality rate. Complex natural products like New Zealand (NZ manuka honey have been revisited and studied extensively as an alternative to antibiotics due to their potent broad-spectrum antimicrobial activity, and the inability to isolate honey-resistant S. aureus. Previous studies showing synergistic effects between manuka-type honeys and antibiotics have been demonstrated against the growth of one methicillin-resistant S. aureus (MRSA strain. We have previously demonstrated strong synergistic activity between NZ manuka-type honey and rifampicin against growth and biofilm formation of multiple S. arueus strains. Here, we have expanded our investigation using multiple S. aureus strains and four different antibiotics commonly used to treat S. aureus-related skin infections: rifampicin, oxacillin, gentamicin and clindamycin. Using checkerboard microdilution and agar diffusion assays with S. aureus strains including clinical isolates and MRSA we demonstrate that manuka-type honey combined with these four antibiotics frequently produces a synergistic effect. In some cases when synergism was not observed, there was a significant enhancement in antibiotic susceptibility. Some strains that were highly resistant to an antibiotic when present alone become sensitive to clinically-achievable concentrations when combined with honey. However, not all of the S. aureus strains tested responded in the same way to these combinational treatments. Our findings support the use of NZ manuka-type honeys in clinical treatment against S. aureus-related infections and extend their potential use as an antibiotic adjuvant in combinational therapy. Our data also suggest that manuka-type honeys may not work as antibiotic adjuvants for all strains of S. aureus, and this may help determine the mechanistic processes

  3. Staphylococcus aureus sternal osteomyelitis: a rare cause of chest pain

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    Kaur M

    2015-10-01

    Full Text Available Chest pain is a common presenting symptom with a broad differential. Life-threatening cardiac and pulmonary etiologies of chest pain should be evaluated first. However, it is critical to perform a thorough assessment for other sources of chest pain in order to limit morbidity and mortality from less common causes. We present a rare case of a previously healthy 45 year old man who presented with focal, substernal, reproducible chest pain and Staphylococcus aureus bacteremia who was later found to have primary Staphylococcus aureus sternal osteomyelitis.

  4. Tea Tree Oil-Induced Transcriptional Alterations in Staphylococcus aureus

    OpenAIRE

    Cuaron, Jesus A.; Dulal, Santosh; Song, Yang; Singh, Atul K; Montelongo, Cesar E.; Yu, Wanqin; Nagarajan, Vijayaraj; Jayaswal, Radheshyam K.; Wilkinson, Brian J; Gustafson, John E.

    2012-01-01

    Tea tree oil (TTO) is a steam distillate of Melaleuca alternifolia that demonstrates broad-spectrum antibacterial activity. This study was designed to document how TTO challenge influences the Staphylococcus aureus transcriptome. Overall, bioinformatic analyses (S. aureus microarray meta-database) revealed that both ethanol and TTO induce related transcriptional alterations. TTO challenge led to the down-regulation of genes involved with energy-intensive transcription and translation, and alt...

  5. Prevalence of Staphylococcus aureus in Shrimps in Tehran during 2013

    OpenAIRE

    Mohammad Mehdi Soltan Dallal; Abbas Rahimi Foroushani; Sara Sharifi –Yazdi; Mohammad Kazem Sharifi -Yazdi; Noushin Arfatahery

    2016-01-01

    Background During fishing and transport, preservation and quality of fish products are importantas well as storage to prevent the growth of pathogenic and toxin producing bacteria.Staphylococcus aureus is one of the most common causes of sea food-borne diseases worldwidedue to contamination of food by preformed enterotoxins. The aim of this study was to compare theprevalence and contamination of S. aureus in marine and farmed shrimps in Tehran fishery center.Methods: A total of 300 samples, i...

  6. Staphylococcus aureus Shifts toward Commensalism in Response to Corynebacterium Species.

    Science.gov (United States)

    Ramsey, Matthew M; Freire, Marcelo O; Gabrilska, Rebecca A; Rumbaugh, Kendra P; Lemon, Katherine P

    2016-01-01

    Staphylococcus aureus-human interactions result in a continuum of outcomes from commensalism to pathogenesis. S. aureus is a clinically important pathogen that asymptomatically colonizes ~25% of humans as a member of the nostril and skin microbiota, where it resides with other bacteria including commensal Corynebacterium species. Commensal Corynebacterium spp. are also positively correlated with S. aureus in chronic polymicrobial diabetic foot infections, distinct from acute monomicrobial S. aureus infections. Recent work by our lab and others indicates that microbe-microbe interactions between S. aureus and human skin/nasal commensals, including Corynebacterium species, affect S. aureus behavior and fitness. Thus, we hypothesized that S. aureus interactions with Corynebacterium spp. diminish S. aureus virulence. We tested this by assaying for changes in S. aureus gene expression during in vitro mono- versus coculture with Corynebacterium striatum, a common skin and nasal commensal. We observed a broad shift in S. aureus gene transcription during in vitro growth with C. striatum, including increased transcription of genes known to exhibit increased expression during human nasal colonization and decreased transcription of virulence genes. S. aureus uses several regulatory pathways to transition between commensal and pathogenic states. One of these, the quorum signal accessory gene regulator (agr) system, was strongly inhibited in response to Corynebacterium spp. Phenotypically, S. aureus exposed to C. striatum exhibited increased adhesion to epithelial cells, reflecting a commensal state, and decreased hemolysin activity, reflecting an attenuation of virulence. Consistent with this, S. aureus displayed diminished fitness in experimental in vivo coinfection with C. striatum when compared to monoinfection. These data support a model in which S. aureus shifts from virulence toward a commensal state when exposed to commensal Corynebacterium species.

  7. Strain Specific Phage Treatment for Staphylococcus aureus Infection Is Influenced by Host Immunity and Site of Infection.

    Directory of Open Access Journals (Sweden)

    Nathan B Pincus

    Full Text Available The response to multi-drug resistant bacterial infections must be a global priority. While mounting resistance threatens to create what the World Health Organization has termed a "post-antibiotic era", the recent discovery that antibiotic use may adversely impact the microbiome adds further urgency to the need for new developmental approaches for anti-pathogen treatments. Methicillin-resistant Staphylococcus aureus (MRSA, in particular, has declared itself a serious threat within the United States and abroad. A potential solution to the problem of antibiotic resistance may not entail looking to the future for completely novel treatments, but instead looking into our history of bacteriophage therapy. This study aimed to test the efficacy, safety, and commercial viability of the use of phages to treat Staphylococcus aureus infections using the commercially available phage SATA-8505. We found that SATA-8505 effectively controls S. aureus growth and reduces bacterial viability both in vitro and in a skin infection mouse model. However, this killing effect was not observed when phage was cultured in the presence of human whole blood. SATA-8505 did not induce inflammatory responses in peripheral blood mononuclear cultures. However, phage did induce IFN gamma production in primary human keratinocyte cultures and induced inflammatory responses in our mouse models, particularly in a mouse model of chronic granulomatous disease. Our findings support the potential efficacy of phage therapy, although regulatory and market factors may limit its wider investigation and use.

  8. Ultraviolet disinfection of antibiotic resistant bacteria and their antibiotic resistance genes in water and wastewater.

    Science.gov (United States)

    McKinney, Chad W; Pruden, Amy

    2012-12-18

    Disinfection of wastewater treatment plant effluent may be an important barrier for limiting the spread of antibiotic-resistant bacteria (ARBs) and antibiotic resistance genes (ARGs). While ideally disinfection should destroy ARGs, to prevent horizontal gene transfer to downstream bacteria, little is known about the effect of conventional water disinfection technologies on ARGs. This study examined the potential of UV disinfection to damage four ARGs, mec(A), van(A), tet(A), and amp(C), both in extracellular form and present within a host ARBs: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE), Escherichia coli SMS-3-5, and Pseudomonas aeruginosa 01, respectively. An extended amplicon-length quantitative polymerase chain reaction assay was developed to enhance capture of ARG damage events and also to normalize to an equivalent length of target DNA (∼1000 bp) for comparison. It was found that the two Gram-positive ARBs (MRSA and VRE) were more resistant to UV disinfection than the two Gram-negative ARBs (E. coli and P. aeruginosa). The two Gram-positive organisms also possessed smaller total genome sizes, which could also have reduced their susceptibility to UV because of fewer potential pyrimidine dimer targets. An effect of cell type on damage to ARGs was only observed in VRE and P. aeruginosa, the latter potentially because of extracellular polymeric substances. In general, damage of ARGs required much greater UV doses (200-400 mJ/cm² for 3- to 4-log reduction) than ARB inactivation (10-20 mJ/cm² for 4- to 5-log reduction). The proportion of amplifiable ARGs following UV treatment exhibited a strong negative correlation with the number of adjacent thymines (Pearson r 0.85; p disinfection technologies should be explored.

  9. Structural and functional characterization of Staphylococcus aureus dihydrodipicolinate synthase.

    Science.gov (United States)

    Girish, Tavarekere S; Sharma, Eshita; Gopal, B

    2008-08-20

    Lysine biosynthesis is crucial for cell-wall formation in bacteria. Enzymes involved in lysine biosynthesis are thus potential targets for anti-microbial therapeutics. Dihydrodipicolinate synthase (DHDPS) catalyzes the first step of this pathway. Unlike its homologues, Staphylococcus aureus DHDPS is a dimer both in solution and in the crystal and is not feedback inhibited by lysine. The crystal structure of S. aureus DHDPS in the free and substrate bound forms provides a structural rationale for its catalytic mechanism. The structure also reveals unique conformational features of the S. aureus enzyme that could be crucial for the design of specific non-competitive inhibitors.

  10. Evaluation of phenotypic and genotypic methods for epidemiological typing of Staphylococcus aureus isolates from bovine mastitis in Denmark

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Wegener, H. C.; Rosdahl, V. T.

    1995-01-01

    The value of five different typing methods (antibiogram typing, biotyping, phage typing, plasmid profiling and restriction fragment length polymorphism of the gene encoding 16S and 23S ribosomal RNA (ribotyping)), in discriminating 105 Staphylococcus aureus strains from bovine milk samples obtained...... from 105 different Danish dairy herds was investigated. A total of 85 strains (81%) proved susceptible to all of the 11 antibiotics tested, and the remaining 20 strains could be divided into 5 different antibiogram patterns. The predominant resistance pattern, penicillin resistance, was observed in 15...... (75%) of the 20 antibiotic resistant strains. Biotyping assigned the strains to 14 different types, with the most common type accounting for 25.7% of the strains. Ninety eight (93.3%) strains could be typed by phages, assigning them to 19 different phage types. The predominant phage type accounted...

  11. Mild Staphylococcus aureus Skin Infection Improves the Course of Subsequent Endogenous S. aureus Bacteremia in Mice.

    Directory of Open Access Journals (Sweden)

    Sanne van den Berg

    Full Text Available Staphylococcus aureus carriers with S. aureus bacteremia may have a reduced mortality risk compared to non-carriers. A role for the immune system is suggested. Here, we study in mice the effect of mild S. aureus skin infection prior to endogenous or exogenous S. aureus bacteremia, and evaluate protection in relation to anti-staphylococcal antibody levels. Skin infections once or twice by a clinical S. aureus isolate (isolate P or S. aureus strain 8325-4 were induced in mice free of S. aureus and anti-staphylococcal antibodies. Five weeks later, immunoglobulin G (IgG levels in blood against 25 S. aureus antigens were determined, and LD50 or LD100 bacteremia caused by S. aureus isolate P was induced. S. aureus skin infections led to elevated levels of anti-staphylococcal IgG in blood. One skin infection improved the course of subsequent severe endogenous bacteremia only. A second skin infection further improved animal survival rate, which was associated with increased pre-bacteremia IgG levels against Efb, IsaA, LukD, LukE, Nuc, PrsA and WTA. In conclusion, S. aureus isolate P skin infection in mice reduces the severity of subsequent endogenous S. aureus bacteremia only. Although cellular immune effects cannot be rules out, anti-staphylococcal IgG against specified antigens may contribute to this effect.

  12. Quantitation of Staphylococcus aureus in seawater using CHROMagar SA.

    Science.gov (United States)

    Tice, Alan D; Pombo, David; Hui, Jennifer; Kurano, Michelle; Bankowski, Matthew J; Seifried, Steven E

    2010-01-01

    A microbiological algorithm has been developed to analyze beach water samples for the determination of viable colony forming units (CFU) of Staphylococcus aureus (S. aureus). Membrane filtration enumeration of S. aureus from recreational beach waters using the chromogenic media CHROMagar SA alone yields a positive predictive value (PPV) of 70%. Presumptive CHROMagar SA colonies were confirmed as S. aureus by 24-hour tube coagulase test. Combined, these two tests yield a PPV of 100%. This algorithm enables accurate quantitation of S. aureus in seawater in 72 hours and could support risk-prediction processes for recreational waters. A more rapid protocol, utilizing a 4-hour tube coagulase confirmatory test, enables a 48-hour turnaround time with a modest false negative rate of less than 10%.

  13. Specificity for human hemoglobin enhances Staphylococcus aureus infection

    Science.gov (United States)

    Pishchany, Gleb; McCoy, Amanda L.; Torres, Victor J.; Krause, Jens C.; Crowe, James E.; Fabry, Mary E.; Skaar, Eric P.

    2010-01-01

    SUMMARY Iron is required for bacterial proliferation and Staphylococcus aureus steals this metal from host hemoglobin during invasive infections. This process involves hemoglobin binding to the cell wall of S. aureus, heme extraction, passage through the cell envelope, and degradation to release free iron. Herein we demonstrate an enhanced ability of S. aureus to bind hemoglobin derived from humans as compared to other mammals. Increased specificity for human hemoglobin (hHb) translates into an improved ability to acquire iron and is entirely dependent on the staphylococcal hemoglobin receptor IsdB. This feature affects host-pathogen interaction as demonstrated by the increased susceptibility of hHb expressing mice to systemic staphylococcal infection. Interestingly, enhanced utilization of human hemoglobin is not a uniform property of all bacterial pathogens. These results suggest a step in the evolution of S. aureus to better colonize the human host and establish hHb expressing mice as a model of S. aureus pathogenesis. PMID:21147468

  14. Staphylococcus aureus shifts towards commensalism in response to Corynebacterium species

    Directory of Open Access Journals (Sweden)

    Matthew M Ramsey

    2016-08-01

    Full Text Available Staphylococcus aureus–human interactions result in a continuum of outcomes from commensalism to pathogenesis. S. aureus is a clinically important pathogen that asymptomatically colonizes ~25% of humans as a member of the nostril and skin microbiota, where it resides with other bacteria including commensal Corynebacterium species. Commensal Corynebacterium spp. are also positively correlated with S. aureus in chronic polymicrobial diabetic foot infections, distinct from acute monomicrobial S. aureus infections. Recent work by our lab and others indicates that microbe-microbe interactions between S. aureus and human skin/nasal commensals, including Corynebacterium species, affect S. aureus behavior and fitness. Thus, we hypothesized that S. aureus interactions with Corynebacterium spp. diminish S. aureus virulence. We tested this by assaying for changes in S. aureus gene expression during in vitro mono- versus coculture with Corynebacterium striatum, a common skin and nasal commensal. We observed a broad shift in S. aureus gene transcription during in vitro growth with C. striatum, including increased transcription of genes known to exhibit increased expression during human nasal colonization and decreased transcription of virulence genes. S. aureus uses several regulatory pathways to transition between commensal and pathogenic states. One of these, the quorum signal accessory gene regulator (agr system, was strongly inhibited in response to Corynebacterium spp. Phenotypically, S. aureus exposed to C. striatum exhibited increased adhesion to epithelial cells, reflecting a commensal state, and decreased hemolysin activity, reflecting an attenuation of virulence. Consistent with this, S. aureus displayed diminished fitness in experimental in vivo coinfection with C. striatum when compared to monoinfection. These data support a model in which S. aureus shifts from virulence towards a commensal state when exposed to commensal Corynebacterium species.

  15. [Epidemiological overview of antibiotic resistance in France and worldwide].

    Science.gov (United States)

    Arlet, Guillaume

    2012-09-01

    Antibiotic resistance appeared early after the introduction of these molecules in therapeutic. But, this resistance has long been confined to care facilities. Twenty years ago, resistance emerged in community with the methicillin resistance in Staphylococcus aureus and also with the reduced susceptibility to penicillin in pneumococci, which are good examples. Fortunately, for these two species, in France, the situation appears to be controlled. The most worrying now is the emergence of resistance to major antimicrobial agents in Escherichia coli both in community and in hospitals. The third-generation cephalosporins and the fluoroquinolones are concerned. This situation is currently not well controlled here and worldwide. The only recourse remaining carbapenems, antibiotics reserved for hospital use. Unfortunately, new mechanisms of resistance to these molecules are emerging.

  16. Staphylococcus aureus bacteriuria as a prognosticator for outcome of Staphylococcus aureus bacteremia: a case-control study

    Directory of Open Access Journals (Sweden)

    Weinstein Robert A

    2010-07-01

    Full Text Available Abstract Background When Staphylococcus aureus is isolated in urine, it is thought to usually represent hematogenous spread. Because such spread might have special clinical significance, we evaluated predictors and outcomes of S. aureus bacteriuria among patients with S. aureus bacteremia. Methods A case-control study was performed at John H. Stroger Jr. Hospital of Cook County among adult inpatients during January 2002-December 2006. Cases and controls had positive and negative urine cultures, respectively, for S. aureus, within 72 hours of positive blood culture for S. aureus. Controls were sampled randomly in a 1:4 ratio. Univariate and multivariable logistic regression analyses were done. Results Overall, 59% of patients were African-American, 12% died, 56% of infections had community-onset infections, and 58% were infected with methicillin-susceptible S. aureus (MSSA. Among 61 cases and 247 controls, predictors of S. aureus bacteriuria on multivariate analysis were urological surgery (OR = 3.4, p = 0.06 and genitourinary infection (OR = 9.2, p = 0.002. Among patients who died, there were significantly more patients with bacteriuria than among patients who survived (39% vs. 17%; p = 0.002. In multiple Cox regression analysis, death risks in bacteremic patients were bacteriuria (hazard ratio 2.9, CI 1.4-5.9, p = 0.004, bladder catheter use (2.0, 1.0-4.0, p = 0.06, and Charlson score (1.1, 1.1-1.3, p = 0.02. Neither length of stay nor methicillin-resistant Staphylococcus aureus (MRSA infection was a predictor of S. aureus bacteriuria or death. Conclusions Among patients with S. aureus bacteremia, those with S. aureus bacteriuria had 3-fold higher mortality than those without bacteriuria, even after adjustment for comorbidities. Bacteriuria may identify patients with more severe bacteremia, who are at risk of worse outcomes.

  17. Threat of multidrug resistant Staphylococcus aureus in Western Nepal

    DEFF Research Database (Denmark)

    Bhatta, Dharm R.; Cavaco, Lina; Nath, Gopal;

    2015-01-01

    ObjectiveTo determine the prevalence of methicillin resistant Staphylococcus aureus (MRSA) and antimicrobial susceptibility patterns of the isolates from Manipal Teaching Hospital, Pokhara, Nepal. MethodsThis study was conducted over a period of 11 months (September 2012–August 2013) at the Manip...

  18. Methicillin-Resistant Staphylococcus aureus Colonization among Medical Residents

    Directory of Open Access Journals (Sweden)

    Pascale Trépanier

    2013-01-01

    Full Text Available BACKGROUND: Medical residents may be at risk of becoming colonized by methicillin-resistant Staphylococcus aureus (MRSA during their training. The occupational risk of this specific population is unknown. Furthermore, there are no data regarding MRSA colonization among health care professionals in Quebec.

  19. Multilocus sequence typing of Staphylococcus aureus with DNA array technology

    NARCIS (Netherlands)

    W.B. van Leeuwen (Willem); C. Jay (Corinne); S.V. Snijders (Susan); N. Durin (Nathalia); B. Lacroix (Bruno); H.A. Verbrugh (Henri); M.C. Enright (Mark); A. Troesch (Alain); A.F. van Belkum (Alex)

    2003-01-01

    textabstractA newly developed oligonucleotide array suited for multilocus sequence typing (MLST) of Staphylococcus aureus strains was analyzed with two strain collections in a two-center study. MLST allele identification for the first strain collection fully agreed with conventiona

  20. Surveillance van meticilline resistente Staphylococcus aureus in Nederland in 1990

    NARCIS (Netherlands)

    Frenay HME; van Leeuwen WJ; van Klingeren B; Rost JA; Schot CS

    1991-01-01

    Follow-up studies on the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in Dutch hospitals were continued in 1990. The number of MRSA-isolates in 1990 compared to 1989 is approximately the same. Phage-type pattern and antibiogram were determined for 168 MRSA-isolates from 42 hosp

  1. USA300 Methicillin-resistant Staphylococcus aureus in Cuba

    Directory of Open Access Journals (Sweden)

    Hopman Joost

    2012-01-01

    Full Text Available Abstract Background Methicillin-resistant Staphylococcus aureus is an increasing problem in the Caribbean. We investigated the molecular epidemiology of MRSA isolates on Cuba. Findings The predominant clone was of the spa type t149, followed by community-associated MRSA USA300. Conclusions We report the first molecular typing results of MRSA isolates from Cuba.

  2. Pulsed-field gel electrophoresis typing of Staphylococcus aureus isolates

    Science.gov (United States)

    Pulsed-field gel electrophoresis (PFGE) is the most applied and effective genetic typing method for epidemiological studies and investigation of foodborne outbreaks caused by different pathogens, including Staphylococcus aureus. The technique relies on analysis of large DNA fragments generated by th...

  3. An Interdisciplinary Experiment: Azo-Dye Metabolism by "Staphylococcus Aureus"

    Science.gov (United States)

    Brocklesby, Kayleigh; Smith, Robert; Sharp, Duncan

    2012-01-01

    An interdisciplinary and engaging practical is detailed which offers great versatility in the study of a qualitative and quantitative metabolism of azo-dyes by "Staphylococcus aureus". This practical has broad scope for adaptation in the number and depth of variables to allow a focused practical experiment or small research project. Azo-dyes are…

  4. Increased risk of arterial thromboembolic events after Staphylococcus aureus bacteremia

    DEFF Research Database (Denmark)

    Mejer, N; Gotland, N; Uhre, M L;

    2015-01-01

    OBJECTIVES: An association between infection and arterial thromboembolic events (ATE) has been suggested. Here we examined the risk of myocardial infarction (MI), stroke and other ATE after Staphylococcus aureus bacteremia (SAB). METHODS: Danish register-based nation-wide observational cohort study...

  5. Staphylococcus aureus causing tropical pyomyositis, Amazon Basin, Peru.

    NARCIS (Netherlands)

    Garcia, C.; Hallin, M.; Deplano, A.; Denis, O.; Sihuincha, M.; Groot, R. de; Gotuzzo, E.; Jacobs, J.

    2013-01-01

    We studied 12 Staphylococcus aureus isolates causing tropical pyomyositis in the Amazon Basin of Peru. All isolates were methicillin-susceptible; 11 carried Panton-Valentine leukocidin-encoding genes, and 5 belonged to multilocus sequence type 25 and possessed an extensive set of enterotoxins. Our f

  6. Diabetes and risk of community-acquired Staphylococcus aureus bacteremia

    DEFF Research Database (Denmark)

    Smit, Jesper; Søgaard, Mette; Schønheyder, Henrik Carl;

    2016-01-01

    OBJECTIVE: Patients with diabetes may experience higher risk of Staphylococcus aureus bacteremia (SAB) than patients without diabetes due to decreased immunity or coexisting morbidities. We investigated the risk of community-acquired (CA) SAB in persons with and without diabetes. DESIGN: Using...

  7. Transmissibility of Livestock-associated Methicillin-Resistant Staphylococcus aureus

    NARCIS (Netherlands)

    Hetem, D.J.; Bootsma, M.C.J.; Troelstra, A.; Bonten, M.J.M.

    2013-01-01

    Previous findings have suggested that the nosocomial transmission capacity of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is lower than that of other MRSA genotypes. We therefore performed a 6-month (June 1–November 30, 2011) nationwide study to quantify the single-adm

  8. Genetic Diversity of Staphylococcus aureus in Buruli Ulcer

    NARCIS (Netherlands)

    Amissah, Nana Ama; Glasner, Corinna; Ablordey, Anthony; Tetteh, Caitlin S.; Kotey, Nana Konama; Prah, Isaac; van der Werf, Tjip; Rossen, John W.; van Dijl, Jan Maarten; Stienstra, Ymkje

    2015-01-01

    Background Buruli ulcer (BU) is a necrotizing skin disease caused by Mycobacterium ulcerans. Previous studies have shown that wounds of BU patients are colonized with M. ulcerans and several other microorganisms, including Staphylococcus aureus, which may interfere with wound healing. The present st

  9. Efficacy of extended cefquinome treatment of clinical Staphylococcus aureus mastitis

    NARCIS (Netherlands)

    Swinkels, J. M.; Cox, P.; Schukken, Y. H.; Lam, T. J G M

    2013-01-01

    Clinical Staphylococcus aureus mastitis is difficult to cure. Extended antimicrobial treatment is often advocated as a practical approach to improve cure rates; however, scientific evidence of this hypothesis is lacking. A multi-centered, nonblinded, randomized, positive-controlled clinical trial wa

  10. spa typing for epidemiological surveillance of Staphylococcus aureus

    NARCIS (Netherlands)

    Hallin, Marie; Friedrich, Alexander W; Struelens, Marc J; Caugant, Dominique A.

    2009-01-01

    The spa typing method is based on sequencing of the polymorphic X region of the protein A gene (spa), present in all strains of Staphylococcus aureus. The X region is constituted of a variable number of 24-bp repeats flanked by well-conserved regions. This single-locus sequence-based typing method c

  11. Low efficacy of tobramycin in experimental Staphylococcus aureus endocarditis

    DEFF Research Database (Denmark)

    Lerche, C. J.; Christophersen, L. J.; Trøstrup, H.;

    2015-01-01

    The empiric treatment of infective endocarditis (IE) varies widely and, in some places, a regimen of penicillin in combination with an aminoglycoside is administered. The increasing incidence of Staphylococcus aureus IE, poor tissue penetration by aminoglycosides and low frequency of penicillin...

  12. Natural Population Dynamics and Carriage of Staphylococcus aureus

    NARCIS (Netherlands)

    D.C. Melles (Damian)

    2008-01-01

    textabstractStaphylococcus aureus is a major human pathogen capable of causing a wide range of infections, from relatively mild skin infections such as folliculitis and furunculosis to life-threatening conditions, including sepsis, deep abscesses, pneumonia, osteomyelitis, and infective endocarditis

  13. Methicillin‐resistant Staphylococcus aureus and the media.

    Science.gov (United States)

    Perencevich, Eli N; Treise, Debbie M

    2010-11-01

    How the media communicate and how the scientific community influences the media are important factors to consider in the public health response to emerging pathogens, including methicillin-resistant Staphylococcus aureus. Social representation theory suggests that the media link "the threatening" to commonplace "anchor representations" which can serve to educate or to create fear.

  14. Antibiotic resistance rates in causative agents of infections in diabetic patients: rising concerns.

    Science.gov (United States)

    Boyanova, Lyudmila; Mitov, Ivan

    2013-04-01

    The vicious cycle is that hyperglycemia (≥11.1 mmol/l) or other diabetes-associated factors facilitate or worsen the development of infections and vice versa, the infections deteriorate the glycemic control of the patients. Diabetic patients are prone to some infections, infection recurrences and poor outcomes. Immunocompromised state and frequent antibiotic use are associated with antibiotic resistance of the bacterial pathogens, such as Mycobacterium tuberculosis (in some studies), methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, Gram-negative bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii, bacteria in diabetic foot infections and different opportunistic and rare pathogens or multidrug-resistant strains. Prompt diagnostics and susceptibility testing, early and aggressive surgical and/or antibiotic therapy, and, importantly, good glycemic control are of utmost importance for treatment of antibiotic-resistant infections in diabetic patients.

  15. Tropical Atlantic marine macroalgae with bioactivity against virulent and antibiotic resistant Vibrio

    Directory of Open Access Journals (Sweden)

    Giselle Cristina Silva

    2013-03-01

    Full Text Available The antibacterial activity of ethanol, methanol, hexane and acetone-based extracts of the macroalgae Padina gymnospora (PG, Hypnea musciformes (HM, Ulva fasciata (UF and Caulerpa prolifera (CP was investigated. The disk diffusion method was used to evaluate the algae antimicrobial effect against standard strains of Vibrio parahaemolyticus, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella enterica and five virulent antibiotic-resistant strains of V. brasiliensis, V. xuii and V. navarrensis (isolated from the hemolymph of Litopenaeus vannamei. Ethanol extracts of PG and HM inhibited all Vibrio strains. E. coli and P. aeruginosa were only susceptible to ethanol extracts of PG. Among the methanol extracts, only UF was bioactive, inhibiting V. navarrensis. The observed inhibitory effect of ethanol extracts of PG, HM and UF against virulent antibiotic-resistant bacteria suggests these macroalgal species constitute a potential source of bioactive compounds.

  16. Phytochemical Analysis, Antibacterial Activity of Marrubium vulgare L against Staphylococcus aureus in vitro

    Directory of Open Access Journals (Sweden)

    Saeide Saeidi

    2014-10-01

    Full Text Available Background: Herbal medicines are the major remedy in traditional medical systems and made a great contribution in maintaining human health and in preventing many infectious diseases. The present study was carried out to determine the potential antibacterial effect of ethanol extracts and essential oil of Marrubium vulgare L. against Staphylococcus aureus which is antibiotic resistant. Materials and Methods: All 17 strains of S. aureus isolated from nose and throat sample from 160 healthy subjects, hospital staffs and inpatient in the city of Zabol (Amir Al-Momenin hospital, Zabol, south-eastern Iran were screened during years 2010-2011. In this study, the essential oil of Marrubium vulgare L. obtained by hydrodistillation was analyzed by gas chromatography coupled to mass spectrometry (GC-MS in order to determine their chemical composition. The minimum inhibitory concentrations were investigated to characterize the antimicrobial activities of this essential oil and extract. Results: Thirty-one components in the oil of Marrubium vulgare were identified. The results demonstrated that the major components of the essential oil were γ-Eudesmol (11%, Germacrene (10%, D-Citronelly formate (10%, β-Citronellol (8%, Geranyl tiglate (7.1%, Geranyl formate (6.02%. The least MIC value of extract M. vulgare was 2.5 mg/mL and the highest MIC value of essential oil M. vulgare was 2.5 mg/mL. Conclusion: This investigation showed that the M. vulgare essential oil and extract has a potent antimicrobial activity against S. aureus. The present studies confirm the use of this essential oil and extract as antibacterial agent. Further research is required to evaluate the practical values of therapeutic applications.

  17. Effect of silver nanoparticle geometry on methicillin susceptible and resistant Staphylococcus aureus, and osteoblast viability.

    Science.gov (United States)

    Actis, Lisa; Srinivasan, Anand; Lopez-Ribot, Jose L; Ramasubramanian, Anand K; Ong, Joo L

    2015-07-01

    Orthopedic implant failure as a result of bacterial infection affects approximately 0.5-5% of patients. These infections are often caused by Staphylococcus aureus which is capable of attaching and subsequently forming a biofilm on the implant surface, making it difficult to eradicate with systemic antibiotics. Further, with the emergence of antibiotic-resistant bacteria, alternative treatments are necessary. Silver nanoparticles have received much attention for their broad spectrum antibacterial activity which has been reported to be both size and shape dependent. The purpose of this study was therefore to evaluate the effect of three different geometries on their effect on microbial susceptibility as well as evaluate their effect on bone cell viability. Silver nanoparticles of spherical, triangular and cuboid shapes were synthesized by chemical reduction methods. The susceptibility of S. aureus and methicillin-resistant S. aureus was evaluated a 24 h period and determined using a colorimetric assay. Further, the viability of human fetal osteoblast (hFOB) cells in the presence of the silver nanoparticles was evaluated over a period of 7 days by AlmarBlue fluorescence assay. hFOB morphology was also evaluated by light microscopy imaging. Results indicated that silver nanoparticle geometry did not have an effect on microbiota susceptibility or hFOB viability. However, high concentrations of silver nanoparticles (0.5 nM) conferred significant susceptibility towards the bacteria and significantly reduced hFOB viability. It was also found that the hFOBs exhibited an increasingly reduced viability to lower silver nanoparticle concentrations with an increase in exposure time.

  18. Omics Approaches for the Study of Adaptive Immunity to Staphylococcus aureus and the Selection of Vaccine Candidates

    Science.gov (United States)

    Holtfreter, Silva; Kolata, Julia; Stentzel, Sebastian; Bauerfeind, Stephanie; Schmidt, Frank; Sundaramoorthy, Nandakumar; Bröker, Barbara M.

    2016-01-01

    Staphylococcus aureus is a dangerous pathogen both in hospitals and in the community. Due to the crisis of antibiotic resistance, there is an urgent need for new strategies to combat S. aureus infections, such as vaccination. Increasing our knowledge about the mechanisms of protection will be key for the successful prevention or treatment of S. aureus invasion. Omics technologies generate a comprehensive picture of the physiological and pathophysiological processes within cells, tissues, organs, organisms and even populations. This review provides an overview of the contribution of genomics, transcriptomics, proteomics, metabolomics and immunoproteomics to the current understanding of S. aureus‑host interaction, with a focus on the adaptive immune response to the microorganism. While antibody responses during colonization and infection have been analyzed in detail using immunoproteomics, the full potential of omics technologies has not been tapped yet in terms of T-cells. Omics technologies promise to speed up vaccine development by enabling reverse vaccinology approaches. In consequence, omics technologies are powerful tools for deepening our understanding of the “superbug” S. aureus and for improving its control.

  19. Beyond the chromosome: the prevalence of unique extra-chromosomal bacteriophages with integrated virulence genes in pathogenic Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Bryan Utter

    Full Text Available In Staphylococcus aureus, the disease impact of chromosomally integrated prophages on virulence is well described. However, the existence of extra-chromosomal prophages, both plasmidial and episomal, remains obscure. Despite the recent explosion in bacterial and bacteriophage genomic sequencing, studies have failed to specifically focus on extra-chromosomal elements. We selectively enriched and sequenced extra-chromosomal DNA from S. aureus isolates using Roche-454 technology and uncovered evidence for the widespread distribution of multiple extra-chromosomal prophages (ExPΦs throughout both antibiotic-sensitive and -resistant strains. We completely sequenced one such element comprised of a 43.8 kbp, circular ExPΦ (designated ФBU01 from a vancomycin-intermediate S. aureus (VISA strain. Assembly and annotation of ФBU01 revealed a number of putative virulence determinants encoded within a bacteriophage immune evasion cluster (IEC. Our identification of several potential ExPΦs and mobile genetic elements (MGEs also revealed numerous putative virulence factors and antibiotic resistance genes. We describe here a previously unidentified level of genetic diversity of stealth extra-chromosomal elements in S. aureus, including phages with a larger presence outside the chromosome that likely play a prominent role in pathogenesis and strain diversity driven by horizontal gene transfer (HGT.

  20. Molecular Typing of Staphylococcus aureus Isolated From Clinical Specimens During an Eight-Year Period (2005 - 2012 in Tabriz, Iran

    Directory of Open Access Journals (Sweden)

    Ahangarzadeh Rezaee

    2016-03-01

    Full Text Available Background Antibiotic resistant Staphylococcus aureus is a serious public health problem worldwide. Objectives This study aimed to investigate the susceptibility pattern and molecular typing of S. aureus isolated from clinical specimens of hospitalized patients during eight years, from 2005 to 2012. Materials and Methods A total of 151 randomly selected S. aureus isolates, identified with phenotypic tests and detection of nuc gene, were subjected to antimicrobial susceptibility testing using the disk diffusion method. Moreover, molecular typing of the isolates was carried out by PCR-RFLP based on coa and spa genes. Results All isolates were susceptible to vancomycin and teicoplanin. High rates of susceptibility were also observed with rifampin (98.1%, imipenem (94.7%, and linezolid (94.1%. On the other hand, most of the isolates were resistant against penicillin (95.4%, erythromycin (68.9% and clindamycin (57.6%. Four types of spa and coa were distinguished among the isolates based on PCR results; however, the HaeII digestion resulted in a total of sixteen and nine RFLP patterns for spa and coa genes, respectively. Conclusions The outcome of this study indicates a higher discriminatory power of the RFLP analysis based on the spa gene compared to the coa gene. Moreover, the results of our study reveal that the resistance rate of S. aureus to some antimicrobial agents including linezolid is a growing concern.

  1. Omics Approaches for the Study of Adaptive Immunity to Staphylococcus aureus and the Selection of Vaccine Candidates

    Directory of Open Access Journals (Sweden)

    Silva Holtfreter

    2016-03-01

    Full Text Available Staphylococcus aureus is a dangerous pathogen both in hospitals and in the community. Due to the crisis of antibiotic resistance, there is an urgent need for new strategies to combat S. aureus infections, such as vaccination. Increasing our knowledge about the mechanisms of protection will be key for the successful prevention or treatment of S. aureus invasion. Omics technologies generate a comprehensive picture of the physiological and pathophysiological processes within cells, tissues, organs, organisms and even populations. This review provides an overview of the contribution of genomics, transcriptomics, proteomics, metabolomics and immunoproteomics to the current understanding of S. aureus‑host interaction, with a focus on the adaptive immune response to the microorganism. While antibody responses during colonization and infection have been analyzed in detail using immunoproteomics, the full potential of omics technologies has not been tapped yet in terms of T-cells. Omics technologies promise to speed up vaccine development by enabling reverse vaccinology approaches. In consequence, omics technologies are powerful tools for deepening our understanding of the “superbug” S. aureus and for improving its control.

  2. Antibiotic susceptibility of vancomyin and nitrofurantoin in Staphylococcus aureus isolated from burnt patients in Sulaimaniyah, Iraqi Kurdistan.

    Science.gov (United States)

    Babakir-Mina, Muhammed; Othman, Nasih; Najmuldeen, Hastyar Hamarashid; Noori, Chia Kamil; Fatah, Choman Faraj; Perno, Carlo-Federico; Ciotti, Marco

    2012-10-01

    Burns remain a significant public health problem in terms of morbidity and mortality throughout the world, especially in low and middle-income countries. Burning raptures the skin barriers that normally prevent invasion by microorganisms and infection is a major complication in burn patients. Methicillin resistant Staphylococcus aureus (MRSA) is the most important nosocomial pathogen. This retrospective analysis was conducted in the burn unit of the Department of Microbiology in the Sulamaini Plastic Surgery and Burns Hospital. The analysis is based on data collected from the medical records of 2938 burn patients, hospitalized between May 2008 and December 2011. The clinical samples were taken from various body sources for microbiological tests. Patients with a high percentage of total body surface area burnt (P<0.001) and a longer hospital stay (P<0.001) were more likely to have infection compared to other patients. In addition, among all tested antibiotics, vancomycin and nitrofurantion seem to be the most effective antibiotics for MR- SA. Furthermore there was a significant association between age and antibiotic resistance for all antibiotics except for vancomycin and nitrofurantoin. Resistance to antibiotics increased with advancing age. The wide use of antibiotics in the treatment of bacterial infections has probably led to the emergence and spread of resistant strains. Routine microbiological surveillance and careful in vitro testing prior to antibiotic use and strict adherence to hospital antibiotic policy may help in the prevention and treatment of antibiotic resistant pathogens in burn infections.

  3. Mission Critical: Preventing Antibiotic Resistance

    Science.gov (United States)

    ... Button Past Emails CDC Features Mission Critical: Preventing Antibiotic Resistance Recommend on Facebook Tweet Share Compartir Can you ... spp. So, what can we do to prevent antibiotic resistance in healthcare settings? Patients, healthcare providers, healthcare facility ...

  4. Antibiotic-Resistant Gonorrhea (ARG)

    Science.gov (United States)

    ... Twitter STD on Facebook Sexually Transmitted Diseases (STDs) Antibiotic-Resistant Gonorrhea Basic Information Recommend on Facebook Tweet ... Page Surveillance Trends and Treatment Challenges Laboratory Issues Antibiotic resistance (AR) is the ability of bacteria to ...

  5. Nosocomial infection and its molecular mechanisms of antibiotic resistance.

    Science.gov (United States)

    Xia, Jufeng; Gao, Jianjun; Tang, Wei

    2016-02-01

    Nosocomial infection is a kind of infection, which is spread in various hospital environments, and leads to many serious diseases (e.g. pneumonia, urinary tract infection, gastroenteritis, and puerperal fever), and causes higher mortality than community-acquired infection. Bacteria are predominant among all the nosocomial infection-associated pathogens, thus a large number of antibiotics, such as aminoglycosides, penicillins, cephalosporins, and carbapenems, are adopted in clinical treatment. However, in recent years antibiotic resistance quickly spreads worldwide and causes a critical threat to public health. The predominant bacteria include Methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii. In these bacteria, resistance emerged from antibiotic resistant genes and many of those can be exchanged between bacteria. With technical advances, molecular mechanisms of resistance have been gradually unveiled. In this review, recent advances in knowledge about mechanisms by which (i) bacteria hydrolyze antibiotics (e.g. extended spectrum β-lactamases, (ii) AmpC β-lactamases, carbapenemases), (iii) avoid antibiotic targeting (e.g. mutated vanA and mecA genes), (iv) prevent antibiotic permeation (e.g. porin deficiency), or (v) excrete intracellular antibiotics (e.g. active efflux pump) are summarized.

  6. Duplex Identification of Staphylococcus aureus by Aptamer and Gold Nanoparticles.

    Science.gov (United States)

    Chang, Tianjun; Wang, Libo; Zhao, Kexu; Ge, Yu; He, Meng; Li, Gang

    2016-06-01

    Staphylococcus aureus is the top common pathogen causing infections and food poisoning. Identification of S. aureus is crucial for the disease diagnosis and regulation of food hygiene. Herein, we report an aptamer-AuNPs based method for duplex identification of S. aureus. Using AuNPs as an indicator, SA23, an aptamer against S. aureus, can well identify its target from Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa. Furthermore, we find citrate-coated AuNPs can strongly bind to S. aureus, but not bind to Salmonella enterica and Proteus mirabilis, which leads to different color changes in salt solution. This colorimetric response is capable of distinguishing S. aureus from S. enteritidis and P. mirabilis. Thus, using the aptasensor and AuNPs together, S. aureus can be accurately identified from the common pathogens. This duplex identification system is a promising platform for simple visual identification of S. aureus. Additionally, in the aptasensing process, bacteria are incubated with aptamers and then be removed before the aptamers adding to AuNPs, which may avoid the interactions between bacteria and AuNPs. This strategy can be potentially applied in principle to detect other cells by AuNPs-based aptasensors.

  7. Relationship between antibiotic resistance and sickle cell anemia: preliminary evidence from a pediatric carriage study in Ghana

    Directory of Open Access Journals (Sweden)

    Donkor ES

    2013-07-01

    Full Text Available Eric S Donkor,1 Ebenezer Foster-Nyarko,2 Christabel C Enweronu-Laryea3 1Department of Microbiology, University of Ghana Medical School, Accra, Ghana; 2Department of Medical Laboratory Science, School of Allied Health Sciences, University of Ghana, Accra, Ghana; 3Department of Child Health, University of Ghana Medical School, Accra, GhanaBackground: Antibiotics are frequently used among people with sickle cell anemia (homozygous SS or HbSS disease, especially for prophylaxis. However, the relationship between antibiotic resistance and people with HbSS disease has not been adequately studied, especially in the developing world. The objectives of the study were (1 to compare antibiotic resistance patterns of nasal Staphylococcus aureus between children with HbSS disease and children without HbSS disease (healthy children and (2 to evaluate nasopharyngeal carriage of antibiotic-resistant Streptococcus pneumoniae among children with HbSS disease.Methods: This was a prospective cross-sectional study, and the subjects were children under 12 years old. Nasal swabs were collected from 50 children with HbSS disease and 50 children without HbSS disease. Nasopharyngeal swabs were collected from another group of 92 children with HbSS disease. The nasal and nasopharyngeal swabs were cultured for S. aureus and S. pneumoniae, respectively. Susceptibility testing was carried out on the S. aureus and S. pneumoniae isolates for various antibiotics, including penicillin, ampicillin, cefuroxime, erythromycin, cloxacillin, and cotrimoxazole.Results: The carriage rates of S. aureus among pediatric subjects with HbSS disease and those without HbSS disease were 48% and 50%, respectively (P > 0.05. S. pneumoniae carriage among the pediatric subjects with HbSS disease was 10%. Antibiotic resistance patterns of S. aureus carried by children with HbSS disease and children without HbSS disease were similar, and the S. aureus resistance rates were >40% for the various

  8. Preparation and characterization of chitosan-silver nanocomposite films and their antibacterial activity against Staphylococcus aureus

    Science.gov (United States)

    Regiel, Anna; Irusta, Silvia; Kyzioł, Agnieszka; Arruebo, Manuel; Santamaria, Jesus

    2013-01-01

    In this work different variables have been analyzed in order to optimize the bactericidal properties of chitosan films loaded with silver nanoparticles. The goal was to achieve complete elimination of antibiotic resistant and biofilm forming strains of Staphylococcus aureus after short contact times. The films were produced by solution casting using chitosan as both a stabilizing and reducing agent for the in situ synthesis of embedded silver nanoparticles. We have applied an innovative approach: the influence of the chitosan molecular weight and its deacetylation degree (DD) were analyzed together with the influence of the bacterial concentration and contact time. The best results were obtained with high DD chitosan where a fast reduction was favored; leading to smaller nanoparticles (nucleation is promoted), and a sufficiently high polymer viscosity prevented the resulting nanoparticles from undesired agglomeration. In addition, for the first time, potential detachment of the silver nanoparticles from the films was evaluated and neglected, demonstrating that uncontrolled release of silver nanoparticles from the chitosan films is prevented. The influence of the ionic silver released from the films, silver loading, nanoparticle sizes, contact, and initial number of bacteria was also analyzed to elucidate the mechanism responsible for the strong bactericidal action observed.

  9. Riboflavin-sensitized photooxidation of Ceftriaxone and Cefotaxime. Kinetic study and effect on Staphylococcus aureus.

    Science.gov (United States)

    Reynoso, Eugenia; Spesia, Mariana B; García, Norman A; Biasutti, María A; Criado, Susana

    2015-01-01

    Trace amounts of the widely used β-lactam antibiotics (Atbs) in waste water may cause adverse effects on the ecosystems and contribute to the proliferation of antibiotic-resistant bacteria. On these grounds, kinetic and mechanistic aspects of photosensitized degradation of Ceftriaxone (Cft) and Cefotaxime (Ctx), have been studied in pure water by stationary and time-resolved techniques. Additionally, possible implications of these photoprocesses on the antimicrobial activity of the Atbs have also been investigated. Photoirradiation of aqueous solutions of Cft and Ctx produces the degradation of both Atbs in the presence of Riboflavin (vitamin B2), a well known pigment dissolved in natural aquatic systems. The process occurs through Type I and Type II mechanisms, with effective prevalence of the former. The participation of O2(-), OH and O2((1)Δg) is supported by experiments of oxygen consumption carried out in the presence of specific scavengers for such reactive oxygen species. Microbiological assays exhibit a parallelism between the rate of Cft and Ctx photodegradation and the loss of their bactericidal capacity on Staphylococcus aureus strains. Results contribute to both understanding kinetic and mechanism aspects of the degradation and predicting on natural decay of Atbs waste water-contaminants.

  10. Survival of methicillin-resistant Staphylococcus aureus during thermal processing of frankfurters, summer sausage, and ham.

    Science.gov (United States)

    Campbell, Jonathan A; Dickson, James S; Cordray, Joseph C; Olson, Dennis G; Mendonca, Aubrey F; Prusa, Kenneth J

    2014-01-01

    Infections from antibiotic-resistant bacteria are a major concern for human health professionals around the world. Methicillin-resistant Staphylococcus aureus (MRSA) is just one of the resistant organisms of concern. MRSA prevalence has also been recently reported in retail meat products at rates higher than originally thought. Although the risk of contracting an infection from handling contaminated meat products is thought to be low, very little is known about this organism from a food safety perspective. The objective of this study was to determine the survival of MRSA during thermal processing of frankfurters, summer sausage, and boneless ham. Frankfurters, summer sausage, and boneless ham were manufactured using formulations and processing procedures developed at the Iowa State University meat laboratory. Thermal processing resulted in a significant log reduction (psausage, and frankfurters when compared to uncooked, positive controls for each of the three processed meat products. All products were thermally processed to an internal temperature of 70°C and promptly cooled to 7.2°C. Boneless ham showed the highest log reduction (7.28 logs) from cooking, followed by summer sausage (6.75 logs) and frankfurters (5.53 logs). The results of this study indicate that thermal processing of ham, summer sausage, and frankfurters to 70°C is sufficient to reduce the risk of MRSA as a potential food safety hazard.

  11. Cefazolin-loaded mesoporous silicon microparticles show sustained bactericidal effect against Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Iman K Yazdi

    2014-05-01

    Full Text Available Cefazolin is an antibiotic frequently used in preoperative prophylaxis of orthopedic surgery and to fight secondary infections post-operatively. Although its systemic delivery in a bulk or bolus dose is usually effective, the local and controlled release can increase its effectiveness by lowering dosages, minimizing total drug exposure, abating the development of antibiotic resistance and avoiding the cytotoxic effect. A delivery system based on mesoporous silicon microparticles was developed that is capable of efficiently loading and continuously releasing cefazolin over several days. The in vitro release kinetics from mesoporous silicon microparticles with three different nanopore sizes was evaluated, and minimal inhibitory concentration of cefazolin necessary to eliminate a culture of Staphylococcus aureus was identified to be 250 µg/mL. A milder toxicity toward mesenchymal stem cells was observed from mesoporous silicon microparticles over a 7-day period. Medium pore size-loaded mesoporous silicon microparticles exhibited long-lasting bactericidal properties in a zone inhibition assay while they were able to kill all the bacteria growing in suspension cultures within 24 h. This study demonstrates that the sustained release of cefazolin from mesoporous silicon microparticles provides immediate and long-term control over bacterial growth both in suspension and adhesion while causing minimal toxicity to a population of mesenchymal stem cell. Mesoporous silicon microparticles offer significant advantageous properties for drug delivery applications in tissue engineering as it favorably extends drug bioavailability and stability, while reducing concomitant cytotoxicity to the surrounding tissues.

  12. Effect of biologically synthesised silver nanoparticles on Staphylococcus aureus biofilm quenching and prevention of biofilm formation.

    Science.gov (United States)

    Masurkar, S A; Chaudhari, P R; Shidore, V B; Kamble, S P

    2012-09-01

    The development of green experimental processes for the synthesis of nanoparticles is a need in the field of nanotechnology. In the present study, the authors reported rapid synthesis of silver nanoparticles using fresh leaves extract of Cymbopogan citratus (lemongrass) with increased stability. The synthesised silver nanoparticles were found to be stable for several months. UV-visible spectrophotometric analysis was carried out to assess the synthesis of silver nanoparticles. The synthesised silver nanoparticles were further characterised by using nanoparticle tracking analyser (NTA), transmission electron microscope (TEM) and energy-dispersive x-ray spectra (EDX). The NTA results showed that the mean size was found to be 32 nm. Silver nanoparticles with controlled size and shape were observed under TEM micrograph. The EDX of the nanoparticles confirmed the presence of elemental silver. These silver nanoparticles showed enhanced quorum quenching activity against Staphylococcus aureus biofilm and prevention of biofilm formation which can be seen under inverted microscope (40X). In the near future, silver nanoparticles synthesised using green methods may be used in the treatment of infections caused by a highly antibiotic resistant biofilm.

  13. Staphylococcus aureus and wounds: a review of tea tree oil as a promising antimicrobial.

    Science.gov (United States)

    Halcón, Linda; Milkus, Kelly

    2004-11-01

    Antibiotic-resistant bacteria continue to be a major health concern worldwide. In particular, Staphylococcus aureus, both methicillin-resistant and -sensitive, are of concern in their ability to cause difficult skin and underlying tissue infections. Melaleuca alternifolia oil (tea tree oil), an essential oil, has demonstrated promising efficacy in treating these infections. Tea tree oil has been used for centuries as a botanical medicine, and has only in recent decades surfaced in the scientific literature as a promising adjunctive wound treatment. Tea tree oil is antimicrobial, anti-inflammatory, and has demonstrated ability to activate monocytes. There are few apparent side effects to using tea tree oil topically in low concentrations, with contact dermatitis being the most common. Tea tree oil has been effective as an adjunctive therapy in treating osteomyelitis and infected chronic wounds in case studies and small clinical trials. There is a need for larger clinical trials to further examine efficacy of tea tree oil as an adjunctive wound therapy, as well as improved guidelines for developing plant-based medicines.

  14. Modulation of drug resistance in Staphylococcus aureus by a kaempferol glycoside from Herissantia tiubae (Malvaceae).

    Science.gov (United States)

    Falcão-Silva, Vivyanne S; Silva, Davi A; Souza, Maria de Fátima V; Siqueira-Junior, José P

    2009-10-01

    In an ongoing project to evaluate natural compounds isolated from plants from the Brazilian biodiversity as modulators of antibiotic resistance, kaempferol-3-O-beta-d-(6''-E-p-coumaroyl) glucopyranoside (tiliroside), isolated from Herissantia tiubae (Malvaceae) was investigated using the strain SA-1199B of Staphylococcus aureus, which overexpresses the norA gene encoding the NorA efflux protein which extrudes hydrophilic fluorquinolones and some biocides, such as benzalkonium chloride, cetrimide, acriflavine and ethidium bromide. The minimum inhibitory concentrations (MICs) of the antibiotics and biocides were determined by the microdilution assay in the absence and in the presence of sub-inhibitory concentration of tiliroside. Although tiliroside did not display relevant antibacterial activity (MIC = 256 microg/mL), it modulated the activity of antibiotics, i.e. in combination with antibiotics a reduction in the MIC was observed for norfloxacin (16-fold), ciprofloxacin (16-fold), lomefloxacin (four-fold) and ofloxacin (two-fold), and an impressive reduction in the MICs for the biocides (up to 128-fold). The results presented here represent the first report of a kaempferol glycoside as a putative efflux pump inhibitor in bacteria. The present finding indicates that H. tiubae (and broadly Malvaceae) could serve as a source of plant-derived natural products that modulate bacterial resistance, i.e. a source of potential adjuvants of antibiotics.

  15. Structural and functional analysis of betaine aldehyde dehydrogenase from Staphylococcus aureus.

    Science.gov (United States)

    Halavaty, Andrei S; Rich, Rebecca L; Chen, Chao; Joo, Jeong Chan; Minasov, George; Dubrovska, Ievgeniia; Winsor, James R; Myszka, David G; Duban, Mark; Shuvalova, Ludmilla; Yakunin, Alexander F; Anderson, Wayne F

    2015-05-01

    When exposed to high osmolarity, methicillin-resistant Staphylococcus aureus (MRSA) restores its growth and establishes a new steady state by accumulating the osmoprotectant metabolite betaine. Effective osmoregulation has also been implicated in the acquirement of a profound antibiotic resistance by MRSA. Betaine can be obtained from the bacterial habitat or produced intracellularly from choline via the toxic betaine aldehyde (BA) employing the choline dehydrogenase and betaine aldehyde dehydrogenase (BADH) enzymes. Here, it is shown that the putative betaine aldehyde dehydrogenase SACOL2628 from the early MRSA isolate COL (SaBADH) utilizes betaine aldehyde as the primary substrate and nicotinamide adenine dinucleotide (NAD(+)) as the cofactor. Surface plasmon resonance experiments revealed that the affinity of NAD(+), NADH and BA for SaBADH is affected by temperature, pH and buffer composition. Five crystal structures of the wild type and three structures of the Gly234Ser mutant of SaBADH in the apo and holo forms provide details of the molecular mechanisms of activity and substrate specificity/inhibition of this enzyme.

  16. Staphylococcus aureus reservoirs during traditional Austrian raw milk cheese production.

    Science.gov (United States)

    Walcher, Georg; Gonano, Monika; Kümmel, Judith; Barker, Gary C; Lebl, Karin; Bereuter, Othmar; Ehling-Schulz, Monika; Wagner, Martin; Stessl, Beatrix

    2014-11-01

    Sampling approaches following the dairy chain, including microbiological hygiene status of critical processing steps and physicochemical parameters, contribute to our understanding of how Staphylococcus aureus contamination risks can be minimised. Such a sampling approach was adopted in this study, together with rapid culture-independent quantification of Staph. aureus to supplement standard microbiological methods. A regional cheese production chain, involving 18 farms, was sampled on two separate occasions. Overall, 51·4% of bulk milk samples were found to be Staph. aureus positive, most of them (34·3%) at the limit of culture-based detection. Staph. aureus positive samples >100 cfu/ml were recorded in 17·1% of bulk milk samples collected mainly during the sampling in November. A higher number of Staph. aureus positive bulk milk samples (94·3%) were detected after applying the culture-independent approach. A concentration effect of Staph. aureus was observed during curd processing. Staph. aureus were not consistently detectable with cultural methods during the late ripening phase, but >100 Staph. aureus cell equivalents (CE)/ml or g were quantifiable by the culture-independent approach until the end of ripening. Enterotoxin gene PCR and pulsed-field gel electrophoresis (PFGE) typing provided evidence that livestock adapted strains of Staph. aureus mostly dominate the post processing level and substantiates the belief that animal hygiene plays a pivotal role in minimising the risk of Staph. aureus associated contamination in cheese making. Therefore, the actual data strongly support the need for additional sampling activities and recording of physicochemical parameters during semi-hard cheese-making and cheese ripening, to estimate the risk of Staph. aureus contamination before consumption.

  17. Disruption of Methicillin-resistant Staphylococcus aureus Biofilms with Enzymatic Therapeutics

    Science.gov (United States)

    2015-04-29

    NAVAL MEDICAL RESEARCH UNIT SAN ANTONIO Disruption of Methicillin-resistant Staphylococcus aureus Biofilms with Enzymatic...fold lower than that needed to thoroughly disrupt biofilms in the current investigation. A previous study of α-amylase applied to S. aureus biofilms...Staphylococcus aureus biofilms. Open Microbiology Journal, 2011. 5: p. 21-31. 36. Wu, J.A., et al., Lysostaphin disrupts Staphylococcus aureus and

  18. New epidemiology of Staphylococcus aureus infection in Africa.

    Science.gov (United States)

    Schaumburg, F; Alabi, A S; Peters, G; Becker, K

    2014-07-01

    Research on African Staphylococcus aureus has been largely neglected in the past, despite the cultural and geographical diversity in Africa, which has a significant impact on the epidemiology of this pathogen. The polarity between developed urban societies and remote rural populations (e.g. Pygmies), combined with close contact with animals (e.g. livestock and domestic animals, and wildlife), makes the epidemiology of S. aureus on the African continent unique and fascinating. Here, we try to draw an epidemiological picture of S. aureus colonization and infection in Africa, and focus on the wide spread of Panton-Valentine leukocidin-positive isolates, the emergence of the hypervirulent methicillin-resistant S. aureus (MRSA) clone USA300, and the dissemination of the typical African clone MRSA sequence type 88.

  19. [Recovery of Staphylococcus aureus after acid injury in milk products].

    Science.gov (United States)

    Assis, E M; De Carvalho, E P; Asquieri, E R; Robbs, P G

    1994-01-01

    The growth behavior of Staphylococcus aureus in fresh Cheese (Minas and Muzzarella) during their shelf-life was studied. The possible injury of this microorganism caused by the increasing acidity was also investigated. Raw milk was inoculated with 10(6) cells/ml (S. aureus FRIA-100) and the cheese production was performed according to normal procedures. Minas and muzzarella cheese were stored at 7 degrees C for 40 and 60 days, respectively. At 2-3 days intervals, the following analysis were performed: acidity, pH, S. aureus counting using agar Baird Parker by the traditional methods and by the method recommended by the American Public Health Association to evaluate the reparation of injured cells. We had a secure indication of the presence of injured S. aureus when acidity was in the range of 0.7 to 0.8% expressed in lactic acid and when the cycle was 1.3 log higher than the traditional one.

  20. Environmental Staphylococcus aureus contamination in a Tunisian hospital.

    Science.gov (United States)

    Gharsa, Haythem; Dziri, Raoudha; Klibi, Naouel; Chairat, Sarra; Lozano, Carmen; Torres, Carmen; Bellaaj, Ridha; Slama, Karim Ben

    2016-12-01

    One hundred hospital environment samples were obtained in 2012 in a Tunisian hospital and tested for Staphylococcus aureus recovery. Antimicrobial resistance profile and virulence gene content were determined. Multilocus-sequence-typing (MLST), spa-typing, agr-typing and SmaI-pulsed-field gel electrophoresis (PFGE) were performed. Two methicillin-resistant S. aureus (MRSA) isolates typed as: ST247-t052-SCCmecI-agrI were recovered from the intensive care unit (ICU). Ten samples contained methicillin-susceptible S. aureus (MSSA) and these samples were collected in different services, highlighting the presence of the tst gene encoding the toxic shock syndrome toxin as well as the lukED, hla, hlb, hld and hlgv virulence genes in some of the isolates. In conclusion, we have shown that the hospital environment could be a reservoir contributing to dissemination of virulent S. aureus and MRSA.

  1. Staphylococcus aureus with reduced susceptibility to vancomycin in healthcare settings.

    Science.gov (United States)

    Spagnolo, A M; Orlando, P; Panatto, D; Amicizia, D; Perdelli, F; Cristina, M L

    2014-12-01

    Glycopeptide resistance in Staphylococcus aureus is a source of great concern because, especially in hospitals, this class of antibiotics, particularly vancomycin, is one of the main resources for combating infections caused by methicillin-resistant Staphylococcus aureus strains (MRSA). Reduced susceptibility to vancomycin (VISA) was first described in 1996 in Japan; since then, a phenotype with heterogeneous resistance to vancomycin (h-VISA) has emerged. H-VISA isolates are characterised by the presence of a resistant subpopulation, typically at a rate of 1 in 10(5) organisms, which constitutes the intermediate stage betweenfully vancomycin-susceptible S. aureus (VSSA) and VISA isolates. As VISA phenotypes are almost uniformly cross-resistant to teicoplanin, they are also called Glycopeptides-intermediate Staphylococcus aureus strains (GISA) and, in the case of heterogeneous resistance to glycopeptides, h-GISA. The overall prevalence of h-VISA is low, accounting for approximately 1.3% of all MRSA isolates tested. Mortality due to h-GISA infections is very high (about 70%), especially among patients hospitalised in high-risk departments, such as intensive care units (ICU). Given the great clinical relevance of strains that are heteroresistant to glycopeptides and the possible negative impact on treatment choices, it is important to draw up and implement infection control practices, including surveillance, the appropriate use of isolation precautions, staff training, hand hygiene, environmental cleansing and good antibiotic stewardship.

  2. Problems with rapid agglutination methods for identification of Staphylococcus aureus when Staphylococcus saprophyticus is being tested.

    OpenAIRE

    Gregson, D B; Low, D E; Skulnick, M; Simor, A. E.

    1988-01-01

    Six rapid agglutination tests for identification of Staphylococcus aureus were evaluated by using 62 strains of S. aureus, 63 strains of S. saprophyticus, and 67 strains of other coagulase-negative staphylococci. S. saprophyticus was responsible for 19 of 26 false-positive results and 20 uninterpretable reactions. Thus, urinary staphylococcal isolates that are positive by rapid agglutination tests may require other confirmatory tests for the identification of possible S. saprophyticus.

  3. Ecological Overlap and Horizontal Gene Transfer in Staphylococcus aureus and Staphylococcus epidermidis

    OpenAIRE

    Méric, Guillaume; Miragaia, Maria; de Been, Mark; Yahara, Koji; Pascoe, Ben; Mageiros, Leonardos; Mikhail, Jane; Harris, Llinos G; Wilkinson, Thomas S.; Rolo, Joana; Lamble, Sarah; Bray, James E.; Jolley, Keith A.; Hanage, William P.; Bowden, Rory

    2015-01-01

    The opportunistic pathogens Staphylococcus aureus and Staphylococcus epidermidis represent major causes of severe nosocomial infection, and are associated with high levels of mortality and morbidity worldwide. These species are both common commensals on the human skin and in the nasal pharynx, but are genetically distinct, differing at 24% average nucleotide divergence in 1,478 core genes. To better understand the genome dynamics of these ecologically similar staphylococcal species, we carrie...

  4. Crystal structure of YwpF from Staphylococcus aureus reveals its architecture comprised of a β-barrel core domain resembling type VI secretion system proteins and a two-helix pair.

    Science.gov (United States)

    Lee, Sang Jae; Lee, Kyu-Yeon; Lee, Ki-Young; Kim, Dong-Gyun; Kim, Soon-Jong; Lee, Bong-Jin

    2015-04-01

    The ywpF gene (SAV2097) of the Staphylococcus aureus strain Mu50 encodes the YwpF protein, which may play a role in antibiotic resistance. Here, we report the first crystal structure of the YwpF superfamily from S. aureus at 2.5-Å resolution. The YwpF structure consists of two regions: an N-terminal core β-barrel domain that shows structural similarity to type VI secretion system (T6SS) proteins (e.g., Hcp1, Hcp3, and EvpC) and a C-terminal two-helix pair. Although the monomer structure of S. aureus YwpF resembles those of T6SS proteins, the dimer/tetramer model of S. aureus YwpF is distinct from the functionally important hexameric ring of T6SS proteins. We therefore suggest that the S. aureus YwpF may have a different function compared to T6SS proteins.

  5. Salicylic acid enhances Staphylococcus aureus extracellular adhesin protein expression.

    Science.gov (United States)

    Alvarez, Lucía P; Barbagelata, María S; Cheung, Ambrose L; Sordelli, Daniel O; Buzzola, Fernanda R

    2011-11-01

    One of the virulence factors required by Staphylococcus aureus at the early stages of infection is Eap, a secreted adhesin that binds many host proteins and is upregulated by the two-component regulatory system saeRS. The S. aureus Newman strain harbors a mutation in saeS that is thought to be responsible for the high level of Eap expression in this strain. This study was designed to ascertain whether salicylic acid (SAL) affects the expression of Eap and the internalization of S. aureus into epithelial cells. The strain Newman treated with SAL exhibited increased levels of eap transcription and protein expression. Furthermore, SAL treatment increased the eap promoter activity. SAL treatment enhanced Eap expression in the Newman and in other S. aureus strains that do not carry the mutation in saeS. Internalization of S. aureus eap and sae mutants into the MAC-T epithelial cells was significantly decreased compared with the wild-type counterparts. In conclusion, we demonstrated that a low concentration of SAL increased S. aureus Eap expression possibly due to enhancement of sae. SAL may create the conditions for S. aureus persistence in the host, not only by decreasing the capsular polysaccharide expression as shown before, but also by enhancing Eap expression.

  6. Detection of Staphylococcus Aureus Enterotoxin Genes A-E

    Directory of Open Access Journals (Sweden)

    Dadgar, T. (PhD

    2014-06-01

    Full Text Available Background and Objective: The main cause of spreading staphylococcal infections among patients is the healthy carriers working in hospitals. With the secretion of different sorts of toxins such as entrotoxin, this bacteria can provide the conditions for attacking on the host. The main objective of this study is identification of the characteristics and differences in the Staphylococcus aureus isolated from healthy carriers and from the patients on the basis of enterotoxin genes (sea-see. Material and Methods: One hundred and twenty of the patients and 80 of healthy carriers worked in health centers of Gorgan, north of Iran, were investigated for S. aureus isolate. The isolates were evaluated by PCR for Enterotoxin Genes A-E (SEA to SEE. Results: Enterotoxin genes (SEA to SEE was found in 87.5% of the total isolates and the most frequent one was enterotoxin gene sea (N= 124. The prevalence of these isolates in healthy carriers was significantly higher than those of the patients. Conclusion: Based on the results, the high percentage of S. aureus isolated from clinical samples contains enterotoxin genes. Therefore, Human as the source and carrier of S. aureus is paramount importance, which is due to significant relationship between being toxigenic strains and the source of isolation. Key words: Staphylococcus Aureus; Enterotoxin; Patient; Carrier

  7. In vitro antimicrobial activity of Combretum molle (Combretaceae) against Staphylococcus aureus and Streptococcus agalactiae isolated from crossbred dairy cows with clinical mastitis.

    Science.gov (United States)

    Regassa, Fekadu; Araya, Mengistu

    2012-08-01

    Following the rapidly expanding dairy enterprise, mastitis has remained the most economically damaging disease. The objective of this study was mainly to investigate the in vitro antibacterial activities of ethanol extracts of Combretum molle (R.Br.Ex.G.Don) Engl & Diels (Combretaceae) against antibiotic-resistant and susceptible Staphylococcus aureus and Streptococcus agalactiae isolated from clinical cases of bovine mastitis using agar disc diffusion method. The leaf and bark extracts showed antibacterial activity against S. aureus at concentrations of 3 mg/ml while the stem and seed extract did not show any bioactivity. Although both leaf and bark extracts were handled in the same manner, the antibacterial activity of the bark extract against the bacterial strains had declined gradually to a lower level as time advanced after extraction. The leaf extract had sustained bioactivity for longer duration. The susceptibility of the bacteria to the leaf extract is not obviously different between S. aureus and S. agalactiae. Also, there was no difference in susceptibility to the leaf extract between the antibiotic-resistant and antibiotic-sensitive bacteria. Further phytochemical and in vivo efficacy and safety studies are required to evaluate the therapeutic value of the plant against bovine mastitis.

  8. [recovery Of Staphylococcus Aureus After Acid Injury In Milk Products].

    OpenAIRE

    Assis, E M; CARVALHO, E.P. de; E.R. Asquieri; Robbs, P G

    2015-01-01

    The growth behavior of Staphylococcus aureus in fresh Cheese (Minas and Muzzarella) during their shelf-life was studied. The possible injury of this microorganism caused by the increasing acidity was also investigated. Raw milk was inoculated with 10(6) cells/ml (S. aureus FRIA-100) and the cheese production was performed according to normal procedures. Minas and muzzarella cheese were stored at 7 degrees C for 40 and 60 days, respectively. At 2-3 days intervals, the following analysis were p...

  9. CHARACTERISATION OF METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS ISOLATES FROM SHINGLES PATIENTS

    Directory of Open Access Journals (Sweden)

    Jasmine R. et al.

    2011-11-01

    Full Text Available Even after treating Shingles patients with antiviral drugs, they are found to suffer from secondary bacterial infections. With this background as a guide, we undertook an investigation to isolate the bacterial pathogens from the pus of Shingles patients. Among the isolates obtained during the one year study period, Staphylococcus aureus sp. was found to be multi drug resistant and hence it was chosen for the study. The antibiogram pattern of the methicillin resistant S. aureus was obtained, since this could serve as a tool for suggesting useful drugs.

  10. Epidemic Increase in Methicillin-resistant Staphylococcus aureus in Copenhagen

    DEFF Research Database (Denmark)

    Westh, Henrik; Boye, Kit; Bartels, Mette Damkjær;

    2006-01-01

    in 2004. All isolates have been spa-typed and epidemiologic information collected. RESULTS: The number of MRSA cases has a doubling time of about six months. The epidemic has been caused by many different MRSA types and 31 staphylococcus protein A genotypes (spa types). MRSA has caused several hospital......INTRODUCTION: We have found an epidemic increase in methicillin-resistant Staphylococcus aureus (MRSA) in Copenhagen. The increase has a complex background and involves hospitals, nursing homes and persons nursed in their own home. MATERIAL AND METHODS: We found 33 MRSA patients in 2003 and 121...

  11. Mastitis Bovina: Resistencia a antibióticos de cepas de Staphylococcus aureus asiladas de leche (Bovine Mastitis: Antimicrobial resistance of Staphylococcus aureus strains isolated from milk

    Directory of Open Access Journals (Sweden)

    Pellegrino, MS

    2011-07-01

    Full Text Available ResumenLa mastitis bovina es considerada la enfermedad infecciosa del ganado lechero de mayor impacto económico mundial, siendo Staphylococcus aureus el principal agente patógeno en muchos países.SummaryBovine mastitis is a frequent cause of economic loss in worldwide dairy herds, being Staphylococcus aureus the main etiological agent in many countries.

  12. Mastitis Bovina: Resistencia a antibióticos de cepas de Staphylococcus aureus asiladas de leche (Bovine Mastitis: Antimicrobial resistance of Staphylococcus aureus strains isolated from milk)

    OpenAIRE

    Pellegrino, MS; Frola, ID; Odierno, LM; Bogni, CI

    2011-01-01

    ResumenLa mastitis bovina es considerada la enfermedad infecciosa del ganado lechero de mayor impacto económico mundial, siendo Staphylococcus aureus el principal agente patógeno en muchos países.SummaryBovine mastitis is a frequent cause of economic loss in worldwide dairy herds, being Staphylococcus aureus the main etiological agent in many countries.

  13. Staphylococcus epidermidis Esp inhibits Staphylococcus aureus biofilm formation and nasal colonization.

    Science.gov (United States)

    Iwase, Tadayuki; Uehara, Yoshio; Shinji, Hitomi; Tajima, Akiko; Seo, Hiromi; Takada, Koji; Agata, Toshihiko; Mizunoe, Yoshimitsu

    2010-05-20

    Commensal bacteria are known to inhibit pathogen colonization; however, complex host-microbe and microbe-microbe interactions have made it difficult to gain a detailed understanding of the mechanisms involved in the inhibition of colonization. Here we show that the serine protease Esp secreted by a subset of Staphylococcus epidermidis, a commensal bacterium, inhibits biofilm formation and nasal colonization by Staphylococcus aureus, a human pathogen. Epidemiological studies have demonstrated that the presence of Esp-secreting S. epidermidis in the nasal cavities of human volunteers correlates with the absence of S. aureus. Purified Esp inhibits biofilm formation and destroys pre-existing S. aureus biofilms. Furthermore, Esp enhances the susceptibility of S. aureus in biofilms to immune system components. In vivo studies have shown that Esp-secreting S. epidermidis eliminates S. aureus nasal colonization. These findings indicate that Esp hinders S. aureus colonization in vivo through a novel mechanism of bacterial interference, which could lead to the development of novel therapeutics to prevent S. aureus colonization and infection.

  14. Reducing Staphylococcus aureus bacterial counts in a dental clinic using an Ionic Breeze air purifier: a preliminary study.

    Science.gov (United States)

    Hubar, J Sean; Pelon, William; Strother, Elizabeth A; Sicard, F Scott

    2009-01-01

    Aerosols and droplets generated by dental procedures are contaminated with blood and bacteria and represent a potential route for the transmission of disease. This study sought to determine if Ionic Breeze air purifiers are effective in collecting and destroying bacteria found in dental aerosols (such as Staphylococcus aureus). This study placed one Sharper Image Professional Series Ionic Breeze Quadra unit and one Ionic Breeze GP unit (with germicidal protection) in dental operatories within the Louisiana State University School of Dentistry. After six hours of operation, bacterial samples were collected and streaked over surfaces of petri dishes containing trypticase soy sucrose bacitracin agar that had been supplemented with 5% sheep blood. The samples were incubated at 37 degrees C for 48 hours; at that point, the microbial colonies were counted. Additional testing was performed on suspect colonies to identify S. aureus strains and to determine if any of those isolates were pathogenic with or without antibiotic resistance. The Ionic Breeze GP unit killed more than 99% of all bacteria on the stainless steel collecting blades. The non-germicidal Ionic Breeze Quadra air purifier collected numerous bacteria that were found to include some pathogenic strains of S. aureus; however, none of these were resistant to antibiotics.

  15. Genotyping of methicillin resistant staphylococcus aureus from tertiary care hospitals in Coimbatore, South India

    Directory of Open Access Journals (Sweden)

    Toms John Peedikayil Neetu

    2016-01-01

    Full Text Available Background: Globally, methicillin resistant Staphylococcus aureus (MRSA is one of the most common pathogens that causes hospital- and community-acquired infections. The use of molecular typing methods is essential for determining the origin of the isolates, their clonal relations, and also epidemiological investigations. Objective: The purpose of this study was to determine the prevalence of antibiotic-resistant MRSA investigate the accessory gene regulator (agr and staphylococcal cassette chromosome mec (SCCmec types and perform multilocus sequence typing (MLST. Furthermore, the minimum inhibitory concentration of MRSA isolates was determined for vancomycin and daptomycin. Materials and Methods: Two hundred and fifty-nine MRSA isolates were collected from Tertiary Care Hospitals in Coimbatore. Disk diffusion method was employed to assess the sensitivity of MRSA isolates to selected antibiotics and genetic analysis was performed using SCCmec, agr, and MLST typing by multiplex-polymerase chain reaction strategy. Minimal inhibitory concentration (MIC was determined using Ezy MIC (vancomycin and Biomerieux (daptomycin E-test strip. Results: Of 259 MRSA isolates, 209 (80.7% were confirmed as methicillin resistant. Antibiotic susceptibility pattern revealed that all the MRSA isolates were 100% sensitive to linezolid, rifampicin, teicoplanin, and vancomycin. MIC results showed that of 209 MRSA isolates, 10 were found to be vancomycin intermediate S. aureus and 100% of the MRSA isolates were daptomycin-susceptible. The agr group I and SCCmec Type III were the major type among MRSA isolates. In addition to these MLST typing revealed the prevalence of sequence type (ST 239 (SLV of ST8 among the MRSA isolates. Conclusion: This study confirms that ST239 (Brazilian clone of MRSA is predominant in this region which is responsible for the hospital-acquired MRSA infections. Thus, the study also suggests that vancomycin and daptomycin can still be used as an

  16. Comparative genome-scale modelling of Staphylococcus aureus strains identifies strain-specific metabolic capabilities linked to pathogenicity

    Science.gov (United States)

    Bosi, Emanuele; Monk, Jonathan M.; Aziz, Ramy K.; Fondi, Marco; Nizet, Victor; Palsson, Bernhard Ø.

    2016-01-01

    Staphylococcus aureus is a preeminent bacterial pathogen capable of colonizing diverse ecological niches within its human host. We describe here the pangenome of S. aureus based on analysis of genome sequences from 64 strains of S. aureus spanning a range of ecological niches, host types, and antibiotic resistance profiles. Based on this set, S. aureus is expected to have an open pangenome composed of 7,411 genes and a core genome composed of 1,441 genes. Metabolism was highly conserved in this core genome; however, differences were identified in amino acid and nucleotide biosynthesis pathways between the strains. Genome-scale models (GEMs) of metabolism were constructed for the 64 strains of S. aureus. These GEMs enabled a systems approach to characterizing the core metabolic and panmetabolic capabilities of the S. aureus species. All models were predicted to be auxotrophic for the vitamins niacin (vitamin B3) and thiamin (vitamin B1), whereas strain-specific auxotrophies were predicted for riboflavin (vitamin B2), guanosine, leucine, methionine, and cysteine, among others. GEMs were used to systematically analyze growth capabilities in more than 300 different growth-supporting environments. The results identified metabolic capabilities linked to pathogenic traits and virulence acquisitions. Such traits can be used to differentiate strains responsible for mild vs. severe infections and preference for hosts (e.g., animals vs. humans). Genome-scale analysis of multiple strains of a species can thus be used to identify metabolic determinants of virulence and increase our understanding of why certain strains of this deadly pathogen have spread rapidly throughout the world. PMID:27286824

  17. Micheliolide provides protection of mice against Staphylococcus aureus and MRSA infection by down-regulating inflammatory response

    Science.gov (United States)

    Jiang, Xinru; Wang, Yuli; Qin, Yifei; He, Weigang; Benlahrech, Adel; Zhang, Qingwen; Jiang, Xin; Lu, Zhenhui; Ji, Guang; Zheng, Yuejuan

    2017-01-01

    A major obstacle to therapy in intensive care units is sepsis caused by severe infection. In recent years gram-positive (G+) bacteria, most commonly staphylococci, are thought to be the main pathogens. Micheliolide (MCL) was demonstrated to provide a therapeutic role in rheumatoid arthritis, inflammatory intestinal disease, colitis-associated cancer, and lipopolysaccharide (LPS, the main component of G− bacterial cell wall) induced septic shock. We proved here that MCL played an anti-inflammatory role in Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA) induced peritonitis. It inhibited the expression of inflammatory cytokines and chemokines in macrophages and dendritic cells upon stimulation with peptidoglycan (PGN, the main cell wall composition of G+ bacteria). PI3K/Akt and NF-κB pathways account for the anti-inflammatory role of MCL after PGN stimulation. MCL reduced IL-6 secretion through down-regulating NF-κB activation and improved the survival status in mice challenged with a lethal dose of S. aureus. In MRSA infection mouse model, MCL down-regulated the expression of IL-6, TNF-α, MCP-1/CCL2 and IFN-γ in sera, and ameliorated the organ damage of liver and kidney. In conclusion, MCL can help maintain immune equilibrium and decrease PGN, S. aureus and MRSA-triggered inflammatory response. These provide the rationality for the potential usage of MCL in sepsis caused by G+ bacteria (e.g., S. aureus) and antibiotic-resistant bacteria (e.g., MRSA). PMID:28165033

  18. Comparative genome-scale modelling of Staphylococcus aureus strains identifies strain-specific metabolic capabilities linked to pathogenicity.

    Science.gov (United States)

    Bosi, Emanuele; Monk, Jonathan M; Aziz, Ramy K; Fondi, Marco; Nizet, Victor; Palsson, Bernhard Ø

    2016-06-28

    Staphylococcus aureus is a preeminent bacterial pathogen capable of colonizing diverse ecological niches within its human host. We describe here the pangenome of S. aureus based on analysis of genome sequences from 64 strains of S. aureus spanning a range of ecological niches, host types, and antibiotic resistance profiles. Based on this set, S. aureus is expected to have an open pangenome composed of 7,411 genes and a core genome composed of 1,441 genes. Metabolism was highly conserved in this core genome; however, differences were identified in amino acid and nucleotide biosynthesis pathways between the strains. Genome-scale models (GEMs) of metabolism were constructed for the 64 strains of S. aureus These GEMs enabled a systems approach to characterizing the core metabolic and panmetabolic capabilities of the S. aureus species. All models were predicted to be auxotrophic for the vitamins niacin (vitamin B3) and thiamin (vitamin B1), whereas strain-specific auxotrophies were predicted for riboflavin (vitamin B2), guanosine, leucine, methionine, and cysteine, among others. GEMs were used to systematically analyze growth capabilities in more than 300 different growth-supporting environments. The results identified metabolic capabilities linked to pathogenic traits and virulence acquisitions. Such traits can be used to differentiate strains responsible for mild vs. severe infections and preference for hosts (e.g., animals vs. humans). Genome-scale analysis of multiple strains of a species can thus be used to identify metabolic determinants of virulence and increase our understanding of why certain strains of this deadly pathogen have spread rapidly throughout the world.

  19. Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus.

    Science.gov (United States)

    Gottschalk, Sanne; Gottlieb, Caroline T; Vestergaard, Martin; Hansen, Paul R; Gram, Lone; Ingmer, Hanne; Thomsen, Line E

    2015-12-01

    The rapid rise in antibiotic-resistant pathogens is causing increased health concerns, and consequently there is an urgent need for novel antimicrobial agents. Antimicrobial peptides (AMPs), which have been isolated from a wide range of organisms, represent a very promising class of novel antimicrobials. In the present study, the analogue FL9, based on the amphibian AMP fallaxin, was studied to elucidate its mode of action and antibacterial activity against the human pathogen Staphylococcus aureus. Our data showed that FL9 may have a dual mode of action against S. aureus. At concentrations around the MIC, FL9 bound DNA, inhibited DNA synthesis and induced the SOS DNA damage response, whereas at concentrations above the MIC the interaction between S. aureus and FL9 led to membrane disruption. The antibacterial activity of the peptide was maintained over a wide range of NaCl and MgCl(2) concentrations and at alkaline pH, while it was compromised by acidic pH and exposure to serum. Furthermore, at subinhibitory concentrations of FL9, S. aureus responded by increasing the expression of two major virulence factor genes, namely the regulatory rnaIII and hla, encoding α-haemolysin. In addition, the S. aureus-encoded natural tolerance mechanisms included peptide cleavage and the addition of positive charge to the cell surface, both of which minimized the antimicrobial activity of FL9. Our results add new information about FL9 and its effect on S. aureus, which may aid in the future development of analogues with improved therapeutic potential.

  20. Frequency of Antiseptic Resistance Among Staphylococcus aureus and Coagulase-Negative Staphylococci Isolated From a University Hospital in Central Iran

    Science.gov (United States)

    Taheri, Nona; Ardebili, Abdollah; Amouzandeh-Nobaveh, Alireza; Ghaznavi-Rad, Ehsanollah

    2016-01-01

    Objectives Reduced biocide susceptibility in Staphylococci is associated with various antiseptic resistance genes encoding efflux systems. Our aim was to determine the susceptibility to three disinfectant agents, including benzalkonium chloride (BAC), benzethonium chloride (BZT), and chlorhexidine digluconate (CHDG) among clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococci (CoNS). Methods The minimum inhibitory concentration (MIC) of 60 methicillin-resistant S. aureus (MRSA), 54 methicillin-sensitive S. aureus (MSSA) and 51 CoNS isolates from a single hospital to three biocidal agents (BAC, BZT, and CHDG) was determined. Biocide resistance genes (qacA/B, smr, qacG, qacH, qacJ, and norA) were analyzed by the polymerase chain reaction assay. Results All isolates had MICs for BAC and BZT from 0.25 to 8 µg/mL, and for CHDG from 0.5 to 64 µg/mL. qacA/B was the most common biocide resistance gene among all 165 Staphylococcus isolates (76; 46%), which comprised 38 (63.3%) MRSA, 14 (25.9%) MSSA, and 24 (47%) CoNS. Eleven (6.7%) and 24 (14.5%) isolates among the 165 Staphylococci carried smr and norA genes, respectively. In contrast, other resistance genes such as qacG, qacH, and qacJ were absent in all Staphylococci studied. The qacA/B and smr genes were detected concomitantly in 3% of isolates, and 23.6% strains of the total 165 Staphylococcus isolates were negative for each studied gene. Conclusions The carriage of several biocide resistance genes, including qacA/B, smr, and norA, alone or concurrently, is associated with reduced susceptibility. Use of antiseptics may select for antibiotic-resistant strains and assist their survival in the healthcare environment. PMID:27974958

  1. Multilocus sequence typing of Staphylococcus aureus with DNA array technology

    OpenAIRE

    2003-01-01

    textabstractA newly developed oligonucleotide array suited for multilocus sequence typing (MLST) of Staphylococcus aureus strains was analyzed with two strain collections in a two-center study. MLST allele identification for the first strain collection fully agreed with conventional strain typing. Analysis of strains from the second collection revealed that chip-defined MLST was concordant with conventional MLST. Array-mediated MLST data were reproducible, exchangeable, and epidemiologically ...

  2. Methicillin-resistente Staphylococcus aureus (MRSA) in der medizinischen Rehabilitation

    OpenAIRE

    Hergenröder, H.; Mielke, Martin; Höller, C.; Herr, C.

    2012-01-01

    Reha-Kliniken legen im Umgang mit Methicillin-resistentem Staphylococcus aureus (MRSA) häufig das Hygienemanagement der akutmedizinischen Versorgung zugrunde, was Patienten mit positivem MRSA-Status den Zugang in die stationäre Rehabilitation erschwert. In einer Arbeitsgruppe der Bayerischen Landesarbeitsgemeinschaft Multiresistente Erreger (LARE) wurde die Problematik auf Basis einer systematischen Literaturrecherche, der Gründung eines Expertengremiums sowie der Auswertung vorliegender Hygi...

  3. Staphylococcus aureus nasal and pharyngeal carriage in Senegal.

    Science.gov (United States)

    Fall, C; Richard, V; Dufougeray, A; Biron, A; Seck, A; Laurent, F; Breurec, S

    2014-04-01

    Nasal and pharyngeal swabs were collected from 132 patients admitted to the Principal Hospital in Dakar (Senegal), in January and February 2012. The prevalence of Staphylococcus aureus carriage was 56.1% (n = 74): 40.2% for pharyngeal samples and 36.4% for nasal samples. None of the isolates was methicillin-resistant. Carriage was independently associated with being female (p Senegal as compared with industrialized countries.

  4. Phagotherapy faced with Staphylococcus aureus methicilin resistant infections in mice

    OpenAIRE

    Tamariz, Jesús H.; Universidad Peruana Cayetano Heredia. Lima, Perú. Biólogo, doctor en Ciencias Biológicas.; Lezameta, Lizet; Universidad Peruana Cayetano Heredia. Lima, Perú. licenciada en Tecnología Médica.; Guerra, Humberto; Universidad Peruana Cayetano Heredia. Lima

    2014-01-01

    Objectives. To assess the bacteriophage activity in localized and systemic infections caused by Staphylococcus aureus resistant to methicilin (MRSA). Materials and methods. An experimental study was performed in 45 mice of the Balb/c strain divided in nine groups of five individuals. Ten naive bacteriophages were isolated through clinical samples and hospital effluents. Lytic capacity and spectrum activity was evaluated on the basis of which six phages were selected for phagotherapy trials. A...

  5. Extensive Spinal Cord Injury following Staphylococcus aureus Septicemia and Meningitis

    Directory of Open Access Journals (Sweden)

    Nicolas De Schryver

    2011-06-01

    Full Text Available Bacterial meningitis is rarely complicated by spinal cord involvement in adults. We report a case of Staphylococcus aureus septicemia complicated by meningitis and extensive spinal cord injury, leading to ascending brain stem necrosis and death. This complication was investigated by magnetic resonance imaging which demonstrated intramedullary hyperintensity on T2-weighted images and by multimodality evoked potentials. Postmortem microscopic examination confirmed that the extensive spinal cord injury was of ischemic origin, caused by diffuse leptomeningitis and endarteritis.

  6. Nanoscale Plasma Coating Inhibits Formation of Staphylococcus aureus Biofilm

    OpenAIRE

    2015-01-01

    Staphylococcus aureus commonly infects medical implants or devices, with devastating consequences for the patient. The infection begins with bacterial attachment to the device, followed by bacterial multiplication over the surface of the device, generating an adherent sheet of bacteria known as a biofilm. Biofilms resist antimicrobial therapy and promote persistent infection, making management difficult to futile. Infections might be prevented by engineering the surface of the device to disco...

  7. Fatal pneumoni med Panton-Valentine-leukocidinproducerende Staphylococcus aureus

    DEFF Research Database (Denmark)

    Rabøl, Peter Hedelund; Dessau, Ram Benny; Warnecke, Mads

    2010-01-01

    We describe a case of fatal pneumonia in a previously healthy 14-year-old boy. The patient was severely affected at the time of admission with high fever, tachypnea, tachycardia and peripheral cyanosis. The condition worsened despite treatment with antibiotics as well as respiratory and pressure ...... support. Acidosis and critical leucopenia supervened and the patient died just short of 24 hours after admission. Subsequent bacterial cultivation showed Panton-Valentine Leucocidin-producing Staphylococcus aureus....

  8. Changing patterns among the subgroups of strains of Staphylococcus aureus of phage group II in Danish hospitals from 1961-91

    DEFF Research Database (Denmark)

    Eriksen, N H; Hartzen, S H; Bangsborg, Jette Marie

    1994-01-01

    During the period 1961-91 a total of 567,635 strains of Staphylococcus aureus from hospitalized patients in Denmark have been characterized according to their antibiotic resistance, site of isolation and phage type. Strains of phage group II (typed by the phages 3A, 3C, 55 and 71) have been...... analysed further. The occurrence of group II strains was relatively constant (approximately 16%) from 1961 until 1983. Since then the frequency of group II strains increased; in 1991 they accounted for 22.7% of all S. aureus strains isolated. Strains of group II can, on the basis of their phage types......, be divided in four subgroups: 3A, 71, 71+ and the 'rest of group II'. Furthermore, within these groups strains may differ from one another in respect to their sensitivity to phages. The increased isolation of group II strains during recent years was because of an increase in strains of subgroups 71...

  9. Diversity of Staphylococcus aureus Isolates in European Wildlife

    Science.gov (United States)

    Monecke, Stefan; Gavier-Widén, Dolores; Hotzel, Helmut; Peters, Martin; Guenther, Sebastian; Lazaris, Alexandros; Loncaric, Igor; Müller, Elke; Reissig, Annett; Ruppelt-Lorz, Antje; Shore, Anna C.; Walter, Birgit; Coleman, David C.; Ehricht, Ralf

    2016-01-01

    Staphylococcus aureus is a well-known colonizer and cause of infection among animals and it has been described from numerous domestic and wild animal species. The aim of the present study was to investigate the molecular epidemiology of S. aureus in a convenience sample of European wildlife and to review what previously has been observed in the subject field. 124 S. aureus isolates were collected from wildlife in Germany, Austria and Sweden; they were characterized by DNA microarray hybridization and, for isolates with novel hybridization patterns, by multilocus sequence typing (MLST). The isolates were assigned to 29 clonal complexes and singleton sequence types (CC1, CC5, CC6, CC7, CC8, CC9, CC12, CC15, CC22, CC25, CC30, CC49, CC59, CC88, CC97, CC130, CC133, CC398, ST425, CC599, CC692, CC707, ST890, CC1956, ST2425, CC2671, ST2691, CC2767 and ST2963), some of which (ST2425, ST2691, ST2963) were not described previously. Resistance rates in wildlife strains were rather low and mecA-MRSA isolates were rare (n = 6). mecC-MRSA (n = 8) were identified from a fox, a fallow deer, hares and hedgehogs. The common cattle-associated lineages CC479 and CC705 were not detected in wildlife in the present study while, in contrast, a third common cattle lineage, CC97, was found to be common among cervids. No Staphylococcus argenteus or Staphylococcus schweitzeri-like isolates were found. Systematic studies are required to monitor the possible transmission of human- and livestock-associated S. aureus/MRSA to wildlife and vice versa as well as the possible transmission, by unprotected contact to animals. The prevalence of S. aureus/MRSA in wildlife as well as its population structures in different wildlife host species warrants further investigation. PMID:27992523

  10. Detoxification of toxins by bacillithiol in Staphylococcus aureus.

    Science.gov (United States)

    Newton, Gerald L; Fahey, Robert C; Rawat, Mamta

    2012-04-01

    Bacillithiol (BSH), an α-anomeric glycoside of l-cysteinyl-d-glucosaminyl-l-malate, is a major low-molecular-mass thiol found in bacteria such as Bacillus sp., Staphylococcus aureus and Deinococcus radiodurans. Like other low-molecular-mass thiols such as glutathione and mycothiol, BSH is likely to be involved in protection against environmental toxins including thiol-reactive antibiotics. We report here a BSH-dependent detoxification mechanism in S. aureus. When S. aureus Newman strain was treated with monobromobimane and monochlorobimane, the cellular BSH was converted to the fluorescent S-conjugate BS-bimane. A bacillithiol conjugate amidase activity acted upon the BS-bimane to produce Cys-bimane, which was then acetylated by an N-acetyltransferase to generate N-acetyl-Cys-bimane, a mercapturic acid. An S. aureus mutant lacking BSH did not produce mercapturic acid when treated with monobromobimane and monochlorobimane, confirming the involvement of bacillithiol. Furthermore, treatment of S. aureus Newman with rifamycin, the parent compound of the first-line anti-tuberculosis drug, rifampicin, indicated that this thiol-reactive antibiotic is also detoxified in a BSH-dependent manner, since mercapturic acids of rifamycin were observed in the culture medium. These data indicate that toxins and thiol-reactive antibiotics are detoxified to less potent mercapturic acids in a BSH-dependent manner and then exported out of the cell in S. aureus.

  11. Contribution of coagulases towards Staphylococcus aureus disease and protective immunity.

    Directory of Open Access Journals (Sweden)

    Alice G Cheng

    Full Text Available The bacterial pathogen Staphylococcus aureus seeds abscesses in host tissues to replicate at the center of these lesions, protected from host immune cells via a pseudocapsule. Using histochemical staining, we identified prothrombin and fibrin within abscesses and pseudocapsules. S. aureus secretes two clotting factors, coagulase (Coa and von Willebrand factor binding protein (vWbp. We report here that Coa and vWbp together are required for the formation of abscesses. Coa and vWbp promote the non-proteolytic activation of prothrombin and cleavage of fibrinogen, reactions that are inhibited with specific antibody against each of these molecules. Coa and vWbp specific antibodies confer protection against abscess formation and S. aureus lethal bacteremia, suggesting that coagulases function as protective antigens for a staphylococcal vaccine.

  12. Staphylococcus aureus biofilms: recent developments in biofilm dispersal.

    Science.gov (United States)

    Lister, Jessica L; Horswill, Alexander R

    2014-01-01

    Staphylococcus aureus is a major cause of nosocomial and community-acquired infections and represents a significant burden on the healthcare system. S. aureus attachment to medical implants and host tissue, and the establishment of a mature biofilm, play an important role in the persistence of chronic infections. The formation of a biofilm, and encasement of cells in a polymer-based matrix, decreases the susceptibility to antimicrobials and immune defenses, making these infections difficult to eradicate. During infection, dispersal of cells from the biofilm can result in spread to secondary sites and worsening of the infection. In this review, we discuss the current understanding of the pathways behind biofilm dispersal in S. aureus, with a focus on enzymatic and newly described broad-spectrum dispersal mechanisms. Additionally, we explore potential applications of dispersal in the treatment of biofilm-mediated infections.

  13. Genetically enhanced cows resist intramammary Staphylococcus aureus infection.

    Science.gov (United States)

    Wall, Robert J; Powell, Anne M; Paape, Max J; Kerr, David E; Bannerman, Douglas D; Pursel, Vernon G; Wells, Kevin D; Talbot, Neil; Hawk, Harold W

    2005-04-01

    Mastitis, the most consequential disease in dairy cattle, costs the US dairy industry billions of dollars annually. To test the feasibility of protecting animals through genetic engineering, transgenic cows secreting lysostaphin at concentrations ranging from 0.9 to 14 micrograms/ml [corrected] in their milk were produced. In vitro assays demonstrated the milk's ability to kill Staphylococcus aureus. Intramammary infusions of S. aureus were administered to three transgenic and ten nontransgenic cows. Increases in milk somatic cells, elevated body temperatures and induced acute phase proteins, each indicative of infection, were observed in all of the nontransgenic cows but in none of the transgenic animals. Protection against S. aureus mastitis appears to be achievable with as little as 3 micrograms/ml [corrected] of lysostaphin in milk. Our results indicate that genetic engineering can provide a viable tool for enhancing resistance to disease and improve the well-being of livestock.

  14. Repurposing the antihistamine terfenadine for antimicrobial activity against Staphylococcus aureus.

    Science.gov (United States)

    Perlmutter, Jessamyn I; Forbes, Lauren T; Krysan, Damian J; Ebsworth-Mojica, Katherine; Colquhoun, Jennifer M; Wang, Jenna L; Dunman, Paul M; Flaherty, Daniel P

    2014-10-23

    Staphylococcus aureus is a rapidly growing health threat in the U.S., with resistance to several commonly prescribed treatments. A high-throughput screen identified the antihistamine terfenadine to possess, previously unreported, antimicrobial activity against S. aureus and other Gram-positive bacteria. In an effort to repurpose this drug, structure-activity relationship studies yielded 84 terfenadine-based analogues with several modifications providing increased activity versus S. aureus and other bacterial pathogens, including Mycobacterium tuberculosis. Mechanism of action studies revealed these compounds to exert their antibacterial effects, at least in part, through inhibition of the bacterial type II topoisomerases. This scaffold suffers from hERG liabilities which were not remedied through this round of optimization; however, given the overall improvement in activity of the set, terfenadine-based analogues provide a novel structural class of antimicrobial compounds with potential for further characterization as part of the continuing process to meet the current need for new antibiotics.

  15. Local inflammation exacerbates the severity of Staphylococcus aureus skin infection.

    Directory of Open Access Journals (Sweden)

    Christopher P Montgomery

    Full Text Available Staphylococcus aureus is the leading cause of skin infections. In a mouse model of S. aureus skin infection, we found that lesion size did not correlate with bacterial burden. Athymic nude mice had smaller skin lesions that contained lower levels of myeloperoxidase, IL-17A, and CXCL1, compared with wild type mice, although there was no difference in bacterial burden. T cell deficiency did not explain the difference in lesion size, because TCR βδ (-/- mice did not have smaller lesions, and adoptive transfer of congenic T cells into athymic nude mice prior to infection did not alter lesion size. The differences observed were specific to the skin, because mortality in a pneumonia model was not different between wild type and athymic nude mice. Thus, the clinical severity of S. aureus skin infection is driven by the inflammatory response to the bacteria, rather than bacterial burden, in a T cell independent manner.

  16. Synergistic antibacterial activity of Curcumin with antibiotics against Staphylococcus aureus.

    Science.gov (United States)

    Teow, Sin-Yeang; Ali, Syed Atif

    2015-11-01

    This study evaluated the synergistic antibacterial activity of Curcumin with 8 different antibiotic groups. Two reference, one clinical and ten environmental strains of Staphylococcus aureus (S. aureus) were tested. Disc diffusion assay with 25 μg/mL Curcumin demonstrated synergism in combination with a majority of tested antibiotics against S. aureus. However, checkerboard micro dilution assay only showed synergism, fractional inhibitory concentration index (FICI) indifferent interactions but no antagonism was observed. In time-kill curve, appreciable reduction of bacterial cells was also observed in combination therapy (Curcumin + antibiotics) compared to monotherapy (Curcumin or antibiotic(s) alone). The antibiotics with higher synergistic interaction with Curcumin are arranged in a decreasing order: Amikacin > Gentamicin > Ciprofloxacin.

  17. Antimicrobial susceptibility of Staphylococcus aureus and Staphylococcus pseudintermedius isolated from various animals.

    Science.gov (United States)

    Rubin, Joseph E; Ball, Katherine R; Chirino-Trejo, Manuel

    2011-02-01

    This study characterized the antimicrobial susceptibility of 221 Staphylococcus aureus isolated from various species, and 60 canine Staphylococcus pseudintermedius isolated from 1986 through 2000 at the Western College of Veterinary Medicine (WCVM). Resistance of S. aureus was most common to penicillin (31%) and tetracycline (14%); resistance of S. pseudintermedius to penicillin was present in 8% and to tetracycline in 34% of isolates. Resistance to trimethoprim/sulfamethoxazole was only seen among S. pseudintermedius, and there was no resistance to amoxicillin/clavulanate, ampicillin/sulbactam, cephalothin, amikacin, gentamicin, enrofloxacin, chloramphenicol, or rifampin among any isolate. Inducible clindamycin resistance was found in both S. aureus and S. pseudintermedius, highlighting the need for careful interpretation of culture and susceptibility test results. There were significant differences in the minimum inhibitory concentrations of penicillin, ciprofloxacin, enrofloxacin, clindamycin, erythromycin, chloramphenicol, and tetracycline between avian, bovine, equine, and porcine isolates.

  18. Neutrophil-mediated phagocytosis of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Jos A.G. Van Strijp

    2014-09-01

    Full Text Available For invading staphylococci, phagocytosis an killing bij human neutrophils is the biggest threat. Neutrophils are the only cells that can effectively kill staphylococci by engulfment and subsequent bombardment with proteases, amidases, antimicrobial peptides and proteins in concert with reactive oxygen species that are generated during the metabolic burst.Both complement and antibodies are crucial for effective uptake and neutrophil activation. S. aureus is not an innocent bystander in this process. It actively secretes several proteins to impair every single step in this process from receptor modulation, to complement inhibition to neutrophil lysis to protease, antimicrobial peptide inhibition and resistance to reactive oxygen species. For the design of future novel antimicrobial strategies: therapeutic antibodies, vaccines, novel antibiotics, all this should be taken into account. Still the best way to treat diseases is to help to enhance the natural defence mechanism that are already in place.

  19. Effect of Substance P in Staphylococcus aureus and Staphylococcus epidermidis virulence: Implication for skin homeostasis

    Directory of Open Access Journals (Sweden)

    Awa eNdiaye

    2016-04-01

    Full Text Available Staphylococcus aureus and Staphylococcus epidermidis are two major skin associated bacteria, and Substance P (SP is a major skin neuropeptide. Since bacteria are known to sense and response to many human hormones, we investigated the effects of SP on Staphylococci virulence in reconstructed human epidermis model and HaCaT keratinocytes. We show that SP is stimulating the virulence of Staphylococcus aureus and Staphylococcus epidermidis in a reconstructed human epidermis model. qRT-PCR array analysis of 64 genes expressed by keratinocytes in the response to bacterial infection revealed a potential link between the action of SP on Staphylococci and skin physiopathology. qRT-PCR and direct assay of cathelicidin and human β-defensin 2 secretion also provided that demonstration that the action of SP on bacteria is independent of antimicrobial peptide expression by keratinocytes. Considering an effect of SP on S. aureus and S. epidermidis, we observed that SP increases the adhesion potential of both bacteria on keratinocytes. However, SP modulates the virulence of S. aureus and S. epidermidis through different mechanisms. The response of S. aureus is associated with an increase in Staphylococcal Enterotoxin C2 (SEC2 production and a reduction of exolipase processing whereas in S. epidermidis the effect of SP appears mediated by a rise in biofilm formation activity. The Thermo unstable ribosomal Elongation factor Ef-Tu was identified as the SP-interacting protein in S. aureus and S. epidermidis. SP appears as an inter-kingdom communication factor involved in the regulation of bacterial virulence and essential for skin microflora homeostasis.

  20. PREVALENCIA DE Staphylococcus epidermidis Y Staphylococcus aureus EN PACIENTES CON CONJUNTIVITIS

    Directory of Open Access Journals (Sweden)

    P. Hernández-Rodríguez

    2005-12-01

    Full Text Available Con el fin de establecer la prevalencia de Staphylococcus epidermidis y Staphylococcus aureus en pacientes con conjuntivitis, se evaluaron clínica y bacteriológicamente 131 pacientes con diagnóstico clínico presuntivo de conjuntivitis. A cada participante se le tomó muestra de secreción ocular, para la coloración de Gram y cultivo; además, se probó la susceptibilidad de los aislamientos frente a Oxacilina (Ox, Gentamicina (GM, Vancomicina (Va, Trimetoprim Sulfamethoxazole (SXT, Tetraciclina (Te, Cefalothin (CF, Ceftriaxone (CRO y Ciprofloxacina (CIP. El 53% de los cultivos bacteriológicos fueron positivos, donde el 87% de los aislamientos correspondieron a Gram positivos, siendo los más frecuentes Staphylococcus epidermidis (43%, Staphylococcus aureus (30%, Streptococcus sp. (15%, Enterococcus (7%, Corynebacterium sp. 5%. Se observó multirresistencia frente a 3 ó más antibióticos en S. epidermidis (44% y S.aureus (42%. La alta frecuencia de estos microorganismos y la multirresistencia encontrada en este estudio, determinan la importancia que tienen, como posibles patógenos oculares, y la necesidad de implementar las pruebas de susceptibilidad bacteriana en el ámbito oftalmológico. Este es el primer estudio publicado en Colombia sobre la prevalencia de Staphylococcus epidermidis y Staphylococcus aureus en pacientes con conjuntivitis, el cual seguramente originará la iniciación de posteriores investigaciones, encaminadas a determinar el verdadero papel de estos microorganismos, en el proceso infeccioso ocular.

  1. ANTISTAPHYBASE: database of antimicrobial peptides (AMPs) and essential oils (EOs) against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus.

    Science.gov (United States)

    Zouhir, Abdelmajid; Taieb, Malek; Lamine, Mohamed Ashraf; Cherif, Ammar; Jridi, Taoufik; Mahjoubi, Basma; Mbarek, Sarra; Fliss, Ismail; Nefzi, Adel; Sebei, Khaled; Ben Hamida, Jeannette

    2017-03-01

    Staphylococcus aureus and methicillin-resistant S. aureus are major pathogens. The antimicrobial peptides and essential oils (EOs) display narrow- or broad-spectrum activity against bacteria including these strains. A centralized resource, such as a database, designed specifically for anti-S. aureus/anti-methicillin-resistant S. aureus antimicrobial peptides and EOs is therefore needed to facilitate the comprehensive investigation of their structure/activity associations and combinations. The database ANTISTAPHYBASE is created to facilitate access to important information on antimicrobial peptides and essential peptides against methicillin-resistant S. aureus and S. aureus. At the moment, the database contains 596 sequences of antimicrobial peptides produced by diverse organisms and 287 essential oil records. It permits a quick and easy search of peptides based on their activity as well as their general, physicochemical properties and literature data. These data are very useful to perform further bioinformatic or chemometric analysis and would certainly be useful for the development of new drugs for medical use. The ANTISTAPHYBASE database is freely available at: https://www.antistaphybase.com/ .

  2. Staphylococcus aureus adherence to Candida albicans hyphae is mediated by the hyphal adhesin Als3p

    NARCIS (Netherlands)

    Peters, Brian M.; Ovchinnikova, Ekaterina S.; Krom, Bastiaan P.; Schlecht, Lisa Marie; Zhou, Han; Hoyer, Lois L.; Busscher, Henk J.; van der Mei, Henny C.; Jabra-Rizk, Mary Ann; Shirtliff, Mark E.

    2012-01-01

    The bacterium Staphylococcus (St.) aureus and the opportunistic fungus Candida albicans are currently among the leading nosocomial pathogens, often co-infecting critically ill patients, with high morbidity and mortality. Previous investigations have demonstrated preferential adherence of St. aureus

  3. Prevalence of infective endocarditis in patients with Staphylococcus aureus bacteraemia: the value of screening with echocardiography

    DEFF Research Database (Denmark)

    Rasmussen, Rasmus V; Høst, Ulla; Arpi, Magnus;

    2011-01-01

    Staphylococcus aureus infective endocarditis (IE) is a critical medical condition associated with a high morbidity and mortality. In the present study, we prospectively evaluated the importance of screening with echocardiography in an unselected S. aureus bacteraemia (SAB) population....

  4. Mupirocin prophylaxis against nosocomial Staphylococcus aureus infections in nonsurgical patients: a randomized study

    NARCIS (Netherlands)

    M.C. Vos (Margreet); A. Ott (Alewijn); A. Voss (Andreas); J.A.J.W. Kluytmans (Jan); C.M.J.E. Vandenbroucke-Grauls (Christina); M.H.M. Meester (Marlene); P.H.J. van Keulen (Peter); H.A. Verbrugh (Henri); H.F.L. Wertheim (Heiman)

    2004-01-01

    textabstractBACKGROUND: Staphylococcus aureus nasal carriage is a major risk factor for nosocomial S. aureus infection. Studies show that intranasal mupirocin can prevent nosocomial surgical site infections. No data are available on the efficacy of mupirocin in nonsurgical patients

  5. The Significance of Nasal Carriage of Staphylococcus Aureus and the Incidence of Postoperative Wound Infection

    NARCIS (Netherlands)

    R.P. Wenzel (Richard); T. M. Perl

    1995-01-01

    textabstractStaphylococcus aureus infections are associated with considerable morbidity and, in certain situations, mortality. The association between the nasal carriage of S. aureus and subsequent infection has been comprehensively established in a variety of clinical settings, in particular, patie

  6. Correlation between clinical data and antibiotic resistance in coagulase-negative Staphylococcus species isolated from 68 patients with acute post-cataract endophthalmitis.

    Science.gov (United States)

    Chiquet, C; Maurin, M; Altayrac, J; Aptel, F; Boisset, S; Vandenesch, F; Cornut, P L; Romanet, J P; Gain, P; Carricajo, A

    2015-06-01

    Coagulase-negative staphylococci (CNS) cause the majority of post-cataract endophthalmitis, which can lead to anatomical and/or functional loss of the eye. This study reports the antibiotic susceptibilities of CNS isolates associated with acute post-cataract endophthalmitis cases and correlates antibiotic resistance with severity and outcome of infection in these patients. Clinical data (initial ocular examination, final prognosis, antibiotic treatment) and the antibiotic susceptibilities of the isolated CNS strains were obtained from 68 patients with post-surgical endophthalmitis recruited during a 7-year period by the FRench Institutional ENDophthalmitis Study (FRIENDS) group. The CNS strains displayed 100% susceptibility to vancomycin, 70% to fluoroquinolones, 83% to fosfomycin, 46% to imipenem and 18% to piperacillin. The most effective antibiotic combinations were fosfomycin plus a fluoroquinolone and imipenem plus a fluoroquinolone, which were considered adequate in 80% and 58% of patients, respectively. Methicillin resistance was significantly associated with older age (p 0.001), diabetes mellitus (p 0.004), absence of fundus visibility (p 0.06), and poor visual prognosis (p 0.03). Resistance to fluoroquinolones was significantly associated with absence of fundus visibility (p 0.05) and diabetes mellitus (p 0.02). This large prospective study demonstrates that methicillin resistance and, to a lesser extent, fluoroquinolone resistance in CNS strains causing postoperative endophthalmitis are both prevalent in France and associated with a poorer visual prognosis. These results emphasize the need for an effective surveillance of this antibiotic resistance and the development of new diagnostic tools for rapid detection for early optimization of antibiotic therapy in endophthalmitis patients.

  7. Protection of mice against Staphylococcus aureus infection by a recombinant protein ClfA-IsdB-Hlg as a vaccine candidate.

    Science.gov (United States)

    Delfani, Somayeh; Mohabati Mobarez, Ashraf; Imani Fooladi, Abbas Ali; Amani, Jafar; Emaneini, Mohammad

    2016-02-01

    Staphylococcus aureus is one of the most important causes of nosocomial infections. An effective vaccine to prevent S. aureus infections is urgently required due to the dramatic increase in the number of antibiotic-resistant strains. In this report, we evaluated a newly recombinant protein composed of selected antigenic regions of clumping factor A (ClfA), iron surface determinant B (IsdB) and gamma hemolysin B (HlgB) of S. aureus and sequence coding for hydrophobic linkers between three domains. The recombinant gene was constructed in pET-28a (+) and expressed in Escherichia coli BL21. In addition, sequence coding for a His(6)-tag was added followed by a hybrid procedure of nickel chelate protein purification. Immunization of BALB/c mice with the recombinant protein ClfA-IsdB-Hlg evoked antigen-specific antibodies that could opsonize S. aureus cells, enhancing in vitro phagocytosis by macrophages. Vaccination with the recombinant protein also reduced the bacterial load recovered from mice spleen samples and increased survival following the intraperitoneal challenge with pathogenic S. aureus compared to the control mice. Our results showed that the recombinant protein ClfA-IsdB-Hlg is a promising vaccine candidate for the prevention of S. aureus bacteremia infections.

  8. Antibacterial Action of Curcumin against Staphylococcus aureus: A Brief Review

    Science.gov (United States)

    Liew, Kitson; Ali, Syed A.; Khoo, Alan Soo-Beng; Peh, Suat-Cheng

    2016-01-01

    Curcumin, the major constituent of Curcuma longa L. (Zingiberaceae family) or turmeric, commonly used for cooking in Asian cuisine, is known to possess a broad range of pharmacological properties at relatively nontoxic doses. Curcumin is found to be effective against Staphylococcus aureus (S. aureus). As demonstrated by in vitro experiment, curcumin exerts even more potent effects when used in combination with various other antibacterial agents. Hence, curcumin which is a natural product derived from plant is believed to have profound medicinal benefits and could be potentially developed into a naturally derived antibiotic in the future. However, there are several noteworthy challenges in the development of curcumin as a medicine. S. aureus infections, particularly those caused by the multidrug-resistant strains, have emerged as a global health issue and urgent action is needed. This review focuses on the antibacterial activities of curcumin against both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). We also attempt to highlight the potential challenges in the effort of developing curcumin into a therapeutic antibacterial agent. PMID:27956904

  9. Antibacterial Action of Curcumin against Staphylococcus aureus: A Brief Review

    Directory of Open Access Journals (Sweden)

    Sin-Yeang Teow

    2016-01-01

    Full Text Available Curcumin, the major constituent of Curcuma longa L. (Zingiberaceae family or turmeric, commonly used for cooking in Asian cuisine, is known to possess a broad range of pharmacological properties at relatively nontoxic doses. Curcumin is found to be effective against Staphylococcus aureus (S. aureus. As demonstrated by in vitro experiment, curcumin exerts even more potent effects when used in combination with various other antibacterial agents. Hence, curcumin which is a natural product derived from plant is believed to have profound medicinal benefits and could be potentially developed into a naturally derived antibiotic in the future. However, there are several noteworthy challenges in the development of curcumin as a medicine. S. aureus infections, particularly those caused by the multidrug-resistant strains, have emerged as a global health issue and urgent action is needed. This review focuses on the antibacterial activities of curcumin against both methicillin-sensitive S. aureus (MSSA and methicillin-resistant S. aureus (MRSA. We also attempt to highlight the potential challenges in the effort of developing curcumin into a therapeutic antibacterial agent.

  10. Superantigen Profiling of Staphylococcus aureus Infective Endocarditis Isolates

    Science.gov (United States)

    Chung, Jin-Won; Karau, Melissa J.; Greenwood-Quaintance, Kerryl E.; Ballard, Alessandro D.; Tilahun, Ashenafi; Khaleghi, Shahryar Rostamkolaei; David, Chella S.; Patel, Robin; Rajagopalan, Govindarajan

    2014-01-01

    The frequency of superantigen production among Staphylococcus aureus isolates associated with endocarditis is not well defined. We tested 154 S. aureus isolates from definite infective endocarditis cases for the presence of staphylococcal enterotoxins A-E, H and TSST-1 by PCR, ELISA and using an HLA-DR3 transgenic mouse splenocyte proliferation assay. Sixty-three isolates (50.8%) tested positive for at least one superantigen gene, with 21 (16.9%) testing positive for more than two. tst (28.6%) was most common, followed by seb (27%), sea (22.2%), sed (20.6%), see (17.5%), and sec (11.1%). Of 41 methicillin-resistant S. aureus, 21 had superantigen genes, with sed being more frequently detected in this group compared to methicillin-susceptible S. aureus (P<0.05). Superantigen genes were not associated with mortality (P=0.81). 75% of PCR-positive isolates induced robust splenocyte proliferation. Overall, more than half of S. aureus isolates causing endocarditis carry superantigen genes of which most are functional. PMID:24745820

  11. Prevalence of Staphylococcus aureus in Shrimps in Tehran during 2013

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Soltan Dallal

    2015-12-01

    Full Text Available Background During fishing and transport, preservation and quality of fish products are importantas well as storage to prevent the growth of pathogenic and toxin producing bacteria.Staphylococcus aureus is one of the most common causes of sea food-borne diseases worldwidedue to contamination of food by preformed enterotoxins. The aim of this study was to compare theprevalence and contamination of S. aureus in marine and farmed shrimps in Tehran fishery center.Methods: A total of 300 samples, including 150 marine, 150 farmed shrimps were selected duringSeptember 2013 to December 2013. Isolation and identification of S. aureus from isolated sampleswere carried out according to conventional methods, and antibiotic susceptibility test wasperformed by modified Kirby-Bauer disc diffusion methodResults: The results of this study showed that 30% of marine and 20% off armed shrimps werecontaminated with S. aureus. The highest resistance was observed with penicillin and ampicillin,whereas 100% were sensitive to vancomycin, clindamycin, ciprofloxacin, and rifampin.Conclusions: Due to relatively high contamination of shrimp by S. aureus more attention shouldbe given during processing and manufacturing.

  12. Prevalence of Staphylococcus aureus in Shrimps in Tehran during 2013

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Soltan Dallal

    2016-02-01

    Full Text Available Background During fishing and transport, preservation and quality of fish products are importantas well as storage to prevent the growth of pathogenic and toxin producing bacteria.Staphylococcus aureus is one of the most common causes of sea food-borne diseases worldwidedue to contamination of food by preformed enterotoxins. The aim of this study was to compare theprevalence and contamination of S. aureus in marine and farmed shrimps in Tehran fishery center.Methods: A total of 300 samples, including 150 marine, 150 farmed shrimps were selected duringSeptember 2013 to December 2014. Isolation and identification of S. aureus from isolated sampleswere carried out according to conventional methods, and antibiotic susceptibility test wasperformed by modified Kirby-Bauer disc diffusion method.Results: The results of this study showed that 30% of marine and 20% off armed shrimps werecontaminated with S. aureus. The highest resistance was observed with penicillin and ampicillin,whereas 100% were sensitive to vancomycin, clindamycin, ciprofloxacin, and rifampin.Conclusions: Due to relatively high contamination of shrimp by S. aureus more attention shouldbe given during processing and manufacturing.

  13. A systematic review of animal models for Staphylococcus aureus osteomyelitis

    Directory of Open Access Journals (Sweden)

    W Reizner

    2014-03-01

    Full Text Available Staphylococcus aureus (S. aureus osteomyelitis is a significant complication for orthopaedic patients undergoing surgery, particularly with fracture fixation and arthroplasty. Given the difficulty in studying S. aureus infections in human subjects, animal models serve an integral role in exploring the pathogenesis of osteomyelitis, and aid in determining the efficacy of prophylactic and therapeutic treatments. Animal models should mimic the clinical scenarios seen in patients as closely as possible to permit the experimental results to be translated to the corresponding clinical care. To help understand existing animal models of S. aureus, we conducted a systematic search of PubMed and Ovid MEDLINE to identify in vivo animal experiments that have investigated the management of S. aureus osteomyelitis in the context of fractures and metallic implants. In this review, experimental studies are categorised by animal species and are further classified by the setting of the infection. Study methods are summarised and the relevant advantages and disadvantages of each species and model are discussed. While no ideal animal model exists, the understanding of a model’s strengths and limitations should assist clinicians and researchers to appropriately select an animal model to translate the conclusions to the clinical setting.

  14. Characterization of Haemolysin of Staphylococcus aureus Isolated from Food of Animal Origin

    Directory of Open Access Journals (Sweden)

    Dwi Ariyanti

    2015-11-01

    Full Text Available Staphylococcus aureus is an important pathogen bacteria causing food poisoning and various infection in animals and humans. Haemolysin is one of the virulence factors of Staphylococcus aureus. The aims of the research were to characterize haemolysins of Staphylococcus aureus isolated from various food of animal origin, phenotypic- and genotypically. In the present study, eleven Staphylococcus aureus isolated from various food of animal origins from traditional markets and supermarkets in Yogyakarta, Sidoarjo, Jakarta, and Bandung were characterized for haemolysin, pheno- and genotypically. Characterization of haemolysin phenotypically based on haemolysis pattern of Staphylococcus aureus on sheep blood agar plate. Genes encoding hemolysin were amplified with specific primers by using polymerase chain reaction (PCR technique. The results of the studies showed that Staphylococcus aureus on sheep blood agar plates revealed an alpha haemolysis pattern (18,18%, beta haemolysis (27,27% and gamma haemolysis (54,55%. Based on amplification of the gene encoding haemolysin of Staphylococcus aureus with specific primers showed hla genes (81,81%, and hla combined with hlb genes (18,18%. The amplification of gene hla and hlb had a single amplicon with a size of approximately 534 bp and 833 bp, respectively. The haemolysin characteristics of Staphylococcus aureus from various food of animal origin could be used as important information to control staphylococcal food poisoning.Keywords : Staphylococcus aureus, haemolysin, PCR, food of animal origins

  15. Prevalence of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus in Retail Ready-to-Eat Foods in China.

    Science.gov (United States)

    Yang, Xiaojuan; Zhang, Jumei; Yu, Shubo; Wu, Qingping; Guo, Weipeng; Huang, Jiahui; Cai, Shuzhen

    2016-01-01

    Staphylococcus aureus, particularly methicillin-resistant S.aureus (MRSA), is a life-threatening pathogen in humans, and its presence in food is a public health concern. MRSA has been identified in foods in China, but little information is available regarding MRSA in ready-to-eat (RTE) foods. We aimed to investigate the prevalence of S. aureus and MRSA in Chinese retail RTE foods. All isolated S. aureus were tested for antimicrobial susceptibility, and MRSA isolates were further characterized by multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) typing. Of the 550 RTE foods collected from 2011 to 2014, 69 (12.5%) were positive for S. aureus. Contamination levels were mostly in the range of 0.3-10 most probable number (MPN)/g, with five samples exceeding 10 MPN/g. Of the 69 S. aureus isolates, seven were identified as MRSA by cefoxitin disc diffusion test. Six isolates were mecA-positive, while no mecC-positive isolates were identified. In total, 75.8% (47/62) of the methicillin-susceptible S. aureus isolates and all of the MRSA isolates were resistant to three or more antibiotics. Amongst the MRSA isolates, four were identified as community-acquired strains (ST59-MRSA-IVa (n = 2), ST338-MRSA-V, ST1-MRSA-V), while one was a livestock-associated strain (ST9, harboring an unreported SCCmec type 2C2). One novel sequence type was identified (ST3239), the SCCmec gene of which could not be typed. Overall, our findings showed that Chinese retail RTE foods are likely vehicles for transmission of multidrug-resistant S. aureus and MRSA lineages. This is a serious public health risk and highlights the need to implement good hygiene practices.

  16. Staphylococcus aureus small colony variants in diabetic foot infections

    Directory of Open Access Journals (Sweden)

    Estrella Cervantes-García

    2015-03-01

    Full Text Available Background: Staphylococcus aureus (S. aureus is one of the major pathogens causing chronic infections. The ability of S. aureus to acquire resistance to a diverse range of antimicrobial compounds results in limited treatment options, particularly in methicillin-resistant S. aureus (MRSA. A mechanism by which S. aureus develops reduced susceptibility to antimicrobials is through the formation of small colony variants (SCVs. Infections by SCVs of S. aureus are an upcoming problem due to difficulties in laboratory diagnosis and resistance to antimicrobial therapy. Methods: A prospective study was performed on 120 patients diagnosed with both type 2 diabetes mellitus and infected diabetic foot ulcers. The study was carried out from July 2012 to December 2013 in Hospital General de Mexico. The samples were cultured in blood agar, mannitol salt agar, and MacConkey agar media, and incubated at 37°C in aerobic conditions. Results: We describe the first known cases of diabetic foot infections caused by MRSA-SCVs in patients diagnosed with type 2 diabetes mellitus and infected diabetic foot ulcers. In all of our cases, the patients had not received any form of gentamicin therapy. Conclusions: The antibiotic therapy commonly used in diabetic patients with infected diabetic foot ulcers fails in the case of MRSA-SCVs because the intracellular location protects S. aureus-SCVs from the host's defenses and also helps them resist antibiotics. The cases studied in this article add to the spectrum of persistent and relapsing infections attributed to MRSA-SCVs and emphasizes that these variants may also play a relevant role in diabetic foot infections.

  17. Staphylococcus aureus small colony variants in diabetic foot infections

    Science.gov (United States)

    Cervantes-García, Estrella; García-Gonzalez, Rafael; Reyes-Torres, Angélica; Resendiz-Albor, Aldo Arturo; Salazar-Schettino, Paz María

    2015-01-01

    Background Staphylococcus aureus (S. aureus) is one of the major pathogens causing chronic infections. The ability of S. aureus to acquire resistance to a diverse range of antimicrobial compounds results in limited treatment options, particularly in methicillin-resistant S. aureus (MRSA). A mechanism by which S. aureus develops reduced susceptibility to antimicrobials is through the formation of small colony variants (SCVs). Infections by SCVs of S. aureus are an upcoming problem due to difficulties in laboratory diagnosis and resistance to antimicrobial therapy. Methods A prospective study was performed on 120 patients diagnosed with both type 2 diabetes mellitus and infected diabetic foot ulcers. The study was carried out from July 2012 to December 2013 in Hospital General de Mexico. The samples were cultured in blood agar, mannitol salt agar, and MacConkey agar media, and incubated at 37°C in aerobic conditions. Results We describe the first known cases of diabetic foot infections caused by MRSA-SCVs in patients diagnosed with type 2 diabetes mellitus and infected diabetic foot ulcers. In all of our cases, the patients had not received any form of gentamicin therapy. Conclusions The antibiotic therapy commonly used in diabetic patients with infected diabetic foot ulcers fails in the case of MRSA-SCVs because the intracellular location protects S. aureus-SCVs from the host's defenses and also helps them resist antibiotics. The cases studied in this article add to the spectrum of persistent and relapsing infections attributed to MRSA-SCVs and emphasizes that these variants may also play a relevant role in diabetic foot infections. PMID:25787018

  18. New antimicrobial contact catalyst killing antibiotic resistant clinical and waterborne pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Guridi, A. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Diederich, A.-K. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Aguila-Arcos, S.; Garcia-Moreno, M. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Blasi, R.; Broszat, M. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Schmieder, W.; Clauss-Lendzian, E. [Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Sakinc-Gueler, T. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Andrade, R. [Advanced Research Facilities (SGIker), University of the Basque Country, UPV/EHU, 48940 Leioa (Spain); Alkorta, I. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Meyer, C.; Landau, U. [Largentec GmbH, Am Waldhaus 32, 14129 Berlin (Germany); Grohmann, E., E-mail: elisabeth.grohmann@googlemail.com [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany)

    2015-05-01

    Microbial growth on medical and technical devices is a big health issue, particularly when microorganisms aggregate to form biofilms. Moreover, the occurrence of antibiotic-resistant bacteria in the clinical environment is dramatically growing, making treatment of bacterial infections very challenging. In search of an alternative, we studied a novel antimicrobial surface coating based on micro galvanic elements formed by silver and ruthenium with surface catalytic properties. The antimicrobial coating efficiently inhibited the growth of the nosocomial pathogens Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium as demonstrated by the growth inhibition on agar surface and in biofilms of antibiotic resistant clinical E. faecalis, E. faecium, and S. aureus isolates. It also strongly reduced the growth of Legionella in a drinking water pipeline and of Escherichia coli in urine. We postulate a mode of action of the antimicrobial material, which is independent of the release of silver ions. Thus, the novel antimicrobial coating could represent an alternative to combat microbial growth avoiding the toxic side effects of high levels of silver ions on eukaryotic cells. - Highlights: • The novel antimicrobial inhibits growth of clinical staphylococci and enterococci. • The novel antimicrobial inhibits growth of Legionella in drinking water. • A putative mode of action of the antimicrobial coating is presented.

  19. The sortase A substrates FnbpA, FnbpB, ClfA and ClfB antagonize colony spreading of Staphylococcus aureus.

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    Eleni Tsompanidou

    Full Text Available Staphylococcus aureus is an important human pathogen that is renowned both for its rapid transmission within hospitals and the community, and for the formation of antibiotic resistant biofilms on medical implants. Recently, it was shown that S. aureus is able to spread over wet surfaces. This motility phenomenon is promoted by the surfactant properties of secreted phenol-soluble modulins (PSMs, which are also known to inhibit biofilm formation. The aim of the present studies was to determine whether any cell surface-associated S. aureus proteins have an impact on colony spreading. To this end, we analyzed the spreading capabilities of strains lacking non-essential components of the protein export and sorting machinery. Interestingly, our analyses reveal that the absence of sortase A (SrtA causes a hyper-spreading phenotype. SrtA is responsible for covalent anchoring of various proteins to the staphylococcal cell wall. Accordingly, we show that the hyper-spreading phenotype of srtA mutant cells is an indirect effect that relates to the sortase substrates FnbpA, FnbpB, ClfA and ClfB. These surface-exposed staphylococcal proteins are known to promote biofilm formation, and cell-cell interactions. The hyper-spreading phenotype of srtA mutant staphylococcal cells was subsequently validated in Staphylococcus epidermidis. We conclude that cell wall-associated factors that promote a sessile lifestyle of S. aureus and S. epidermidis antagonize the colony spreading motility of these bacteria.

  20. Predictors of Staphylococcus aureus Colonization and Results after Decolonization

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    Tennison L. Malcolm

    2016-01-01

    Full Text Available Protocols for the screening and decolonization of Staphylococcus aureus prior to total joint arthroplasty (TJA have become widely adopted. The goals of this study were to determine: (1 whether implementation of a screening protocol followed by decolonization with mupirocin/vancomycin and chlorhexidine reduces the risk of revision compared with no screening protocol (i.e., chlorhexidine alone and (2 whether clinical criteria could reliably predict colonization with MSSA and/or MRSA. Electronic medical records of primary patients undergoing TJA that were screened (n=3,927 and were not screened (n=1,751 for Staphylococcus aureus at least 4 days prior to surgery, respectively, were retrospectively reviewed. All patients received chlorhexidine body wipes preoperatively. Patients carrying MSSA and MRSA were treated preoperatively with mupirocin and vancomycin, respectively, along with the standard preoperative antibiotics and chlorhexidine body wipes. Screened patients were 50% less likely to require revision due to prosthetic joint infection compared to those not screened (p=0.04. Multivariate regression models were poorly accurate in predicting colonization with MSSA (AUC = 0.58 and MRSA (AUC = 0.62. These results support the routine screening and decolonization of S. aureus prior to TJA.

  1. Nanoscale Plasma Coating Inhibits Formation of Staphylococcus aureus Biofilm.

    Science.gov (United States)

    Xu, Yuanxi; Jones, John E; Yu, Haiqing; Yu, Qingsong; Christensen, Gordon D; Chen, Meng; Sun, Hongmin

    2015-12-01

    Staphylococcus aureus commonly infects medical implants or devices, with devastating consequences for the patient. The infection begins with bacterial attachment to the device, followed by bacterial multiplication over the surface of the device, generating an adherent sheet of bacteria known as a biofilm. Biofilms resist antimicrobial therapy and promote persistent infection, making management difficult to futile. Infections might be prevented by engineering the surface of the device to discourage bacterial attachment and multiplication; however, progress in this area has been limited. We have developed a novel nanoscale plasma coating technology to inhibit the formation of Staphylococcus aureus biofilms. We used monomeric trimethylsilane (TMS) and oxygen to coat the surfaces of silicone rubber, a material often used in the fabrication of implantable medical devices. By quantitative and qualitative analysis, the TMS/O2 coating significantly decreased the in vitro formation of S. aureus biofilms; it also significantly decreased in vivo biofilm formation in a mouse model of foreign-body infection. Further analysis demonstrated TMS/O2 coating significantly changed the protein adsorption, which could lead to reduced bacterial adhesion and biofilm formation. These results suggest that TMS/O2 coating can be used to effectively prevent medical implant-related infections.

  2. Ocorrência de Staphylococcus aureus em queijo tipo "frescal"

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    Almeida Filho Edvaldo Sampaio de

    2000-01-01

    Full Text Available OBJETIVO: Verificar a ocorrência de Staphylococcus aureus em uma amostra de queijo tipo Minas "frescal" comercializado na cidade de Poços de Caldas, MG, de modo a obter subsídios que permitam avaliar o risco potencial que este produto pode representar para a saúde da população consumidora. MÉTODOS: Foi investigada a presença e o número de cepas de Staphylococcus aureus em 80 amostras de queijo tipo Minas "frescal" produzido artesanalmente e comercializado na cidade de Poços de Caldas, MG, Brasil. RESULTADOS: Os resultados obtidos evidenciaram a presença de S. aureus em 40 (50,0% amostras, cujas contagens revelaram valores médios em torno de 10(5/g. CONCLUSÕES: Tais achados parecem ser extremamente preocupantes, pois além de se situarem acima do limite máximo de 10³/g estabelecido pelo Ministério da Saúde, estes valores mostraram-se muito próximos dos requeridos para a produção de enterotoxinas em quantidades suficientes para a ocorrência de surtos de intoxicação alimentar estafilocócica.

  3. Evolutionary Dynamics of Pandemic Methicillin-Sensitive Staphylococcus aureus ST398 and Its International Spread via Routes of Human Migration

    Science.gov (United States)

    McAdam, Paul R.; Sullivan, Sean B.; Knox, Justin R.; Khiabanian, Hossein; Rabadan, Raul; Davies, Peter R.; Fitzgerald, J. Ross; Lowy, Franklin D.

    2017-01-01

    ABSTRACT Methicillin-susceptible Staphylococcus aureus (MSSA) accounts for the majority of S. aureus infections globally, and yet surprisingly little is known about its clonal evolution. We applied comparative whole-genome sequencing (WGS) analyses to epidemiologically and geographically diverse ST398-MSSA, a pandemic lineage affecting both humans and livestock. Bayesian phylogenetic analysis predicted divergence of human-associated ST398-MSSA ~40 years ago. Isolates from Midwestern pigs and veterinarians differed substantially from those in New York City (NYC). Pig ST398 strains contained a large region of recombination representing imports from multiple sequence types (STs). Phylogeographic analyses supported the spread of ST398-MSSA along local cultural and migratory links between parts of the Caribbean, North America, and France, respectively. Applying pairwise single-nucleotide polymorphism (SNP) distances as a measure of genetic relatedness between isolates, we observed that ST398 not only clustered in households but also frequently extended across local social networks. Isolates collected from environmental surfaces reflected the full diversity of colonizing individuals, highlighting their potentially critical role as reservoirs for transmission and diversification. Strikingly, we observed high within-host SNP variability compared to our previous studies on the dominant methicillin-resistant Staphylococcus aureus (MRSA) clone USA300. Our data indicate that the dynamics of colonization, persistence, and transmission differ substantially between USA300-MRSA and ST398-MSSA. Taken together, our study reveals local and international routes of transmission for a major MSSA clone, indicating key impacts of recombination and mutation on genetic diversification and highlighting important ecological differences from epidemic USA300. Our study demonstrates extensive local and international routes of transmission for a major MSSA clone despite the lack of substantial

  4. Effect of clpP and clpC deletion on persister cell number in Staphylococcus aureus.

    Science.gov (United States)

    Springer, Matthew T; Singh, Vineet K; Cheung, Ambrose L; Donegan, Niles P; Chamberlain, Neal R

    2016-08-01

    Staphylococcus aureus is responsible for a wide variety of infections that include superficial skin and soft tissue infections, septicaemia, central nervous system infections, endocarditis, osteomyelitis and pneumonia. Others have demonstrated the importance of toxin-antitoxin (TA) modules in the formation of persisters and the role of the Clp proteolytic system in the regulation of these TA modules. This study was conducted to determine the effect of clpP and clpC deletion on S. aureus persister cell numbers following antibiotic treatment. Deletion of clpP resulted in a significant decrease in persister cells following treatment with oxacillin and erythromycin but not with levofloxacin and daptomycin. Deletion of clpC resulted in a decrease in persister cells following treatment with oxacillin. These differences were dependent on the antibiotic class and the CFU ml-1 in which the cells were treated. Persister revival assays for all the bacterial strains in these studies demonstrated a significant delay in resumption of growth characteristic of persister cells, indicating that the surviving organisms in this study were not likely due to spontaneous antibiotic resistance. Based on our results, ClpP and possibly ClpC play a role in persister cell formation or maintenance, and this effect is dependent on antibiotic class and the CFU ml-1 or the growth phase of the cells.

  5. Structural basis for the beta lactam resistance of PBP2a from methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Lim, Daniel; Strynadka, Natalie C J

    2002-11-01

    The multiple antibiotic resistance of methicillin-resistant strains of Staphylococcus aureus (MRSA) has become a major clinical problem worldwide. The key determinant of the broad-spectrum beta-lactam resistance in MRSA strains is the penicillin-binding protein 2a (PBP2a). Because of its low affinity for beta-lactams, PBP2a provides transpeptidase activity to allow cell wall synthesis at beta-lactam concentrations that inhibit the beta-lactam-sensitive PBPs normally produced by S. aureus. The crystal structure of a soluble derivative of PBP2a has been determined to 1.8 A resolution and provides the highest resolution structure for a high molecular mass PBP. Additionally, structures of the acyl-PBP complexes of PBP2a with nitrocefin, penicillin G and methicillin allow, for the first time, a comparison of an apo and acylated resistant PBP. An analysis of the PBP2a active site in these forms reveals the structural basis of its resistance and identifies features in newly developed beta-lactams that are likely important for high affinity binding.

  6. Nordihydroguaiaretic acid enhances the activities of aminoglycosides against methicillin- sensitive and resistant Staphylococcus aureus in vitro and in vivo.

    Science.gov (United States)

    Cunningham-Oakes, Edward; Soren, Odel; Moussa, Caroline; Rathor, Getika; Liu, Yingjun; Coates, Anthony; Hu, Yanmin

    2015-01-01

    Infections caused by methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) are prevalent. MRSA infections are difficult to treat and there are no new classes of antibiotics produced to the market to treat infections caused by the resistant bacteria. Therefore, using antibiotic enhancers to rescue existing classes of antibiotics is an attractive strategy. Nordihydroguaiaretic acid (NDGA) is an antioxidant compound found in extracts from plant Larrea Tridentata. It exhibits antimicrobial activity and may target bacterial cell membrane. Combination efficacies of NDGA with many classes of antibiotics were examined by chequerboard method against 200 clinical isolates of MRSA and MSSA. NDGA in combination with gentamicin, neomycin, and tobramycin was examined by time-kill assays. The synergistic combinations of NDGA and aminoglycosides were tested in vivo using a murine skin infection model. Calculations of the fractional inhibitory concentration index (FICI) showed that NDGA when combined with gentamicin, neomycin, or tobramycin displayed synergistic activities in more than 97% of MSSA and MRSA, respectively. Time kill analysis demonstrated that NDGA significantly augmented the activities of these aminoglycosides against MRSA and MSSA in vitro and in murine skin infection model. The enhanced activity of NDGA resides on its ability to damage bacterial cell membrane leading to accumulation of the antibiotics inside bacterial cells. We demonstrated that NDGA strongly revived the therapeutic potencies of aminoglycosides in vitro and in vivo. This combinational strategy could contribute major clinical implications to treat antibiotic resistant bacterial infections.

  7. Investigating the Antibiotic Resistance Problem.

    Science.gov (United States)

    Lawson, Michael; Lawson, Amy L.

    1998-01-01

    Seeks to give teachers useful information on the extent of the problem of antibiotic-resistant bacteria, mechanisms bacteria use to resist antibiotics, the causes of the emergence of antibiotic-resistant organisms, and practices that can prevent or reverse this trend. Contains 19 references. (DDR)

  8. Highly sensitive detection of Staphylococcus aureus directly from patient blood.

    Directory of Open Access Journals (Sweden)

    Padmapriya P Banada

    Full Text Available BACKGROUND: Rapid detection of bloodstream infections (BSIs can be lifesaving. We investigated the sample processing and assay parameters necessary for highly-sensitive detection of bloodstream bacteria, using Staphylococcus aureus as a model pathogen and an automated fluidic sample processing-polymerase chain reaction (PCR platform as a model diagnostic system. METHODOLOGY/PRINCIPAL FINDINGS: We compared a short 128 bp amplicon hemi-nested PCR and a relatively shorter 79 bp amplicon nested PCR targeting the S. aureus nuc and sodA genes, respectively. The sodA nested assay showed an enhanced limit of detection (LOD of 5 genomic copies per reaction or 10 colony forming units (CFU per ml blood over 50 copies per reaction or 50 CFU/ml for the nuc assay. To establish optimal extraction protocols, we investigated the relative abundance of the bacteria in different components of the blood (white blood cells (WBCs, plasma or whole blood, using the above assays. The blood samples were obtained from the patients who were culture positive for S. aureus. Whole blood resulted in maximum PCR positives with sodA assay (90% positive as opposed to cell-associated bacteria (in WBCs (71% samples positive or free bacterial DNA in plasma (62.5% samples positive. Both the assays were further tested for direct detection of S. aureus in patient whole blood samples that were contemporaneous culture positive. S. aureus was detected in 40/45 of culture-positive patients (sensitivity 89%, 95% CI 0.75-0.96 and 0/59 negative controls with the sodA assay (specificity 100%, 95% CI 0.92-1. CONCLUSIONS: We have demonstrated a highly sensitive two-hour assay for detection of sepsis causing bacteria like S. aureus directly in 1 ml of whole blood, without the need for blood culture.

  9. Staphylococcus aureus resistance to topical antimicrobials in atopic dermatitis*

    Science.gov (United States)

    Bessa, Giancarlo Rezende; Quinto, Vanessa Petry; Machado, Daiane Corrêa; Lipnharski, Caroline; Weber, Magda Blessmann; Bonamigo, Renan Rangel; D'Azevedo, Pedro Alves

    2016-01-01

    Background Topical antimicrobial drugs are indicated for limited superficial pyodermitis treatment, although they are largely used as self-prescribed medication for a variety of inflammatory dermatoses, including atopic dermatitis. Monitoring bacterial susceptibility to these drugs is difficult, given the paucity of laboratory standardization. Objective To evaluate the prevalence of Staphylococcus aureus topical antimicrobial drug resistance in atopic dermatitis patients. Methods We conducted a cross-sectional study of children and adults diagnosed with atopic dermatitis and S. aureus colonization. We used miscellaneous literature reported breakpoints to define S. aureus resistance to mupirocin, fusidic acid, gentamicin, neomycin and bacitracin. Results A total of 91 patients were included and 100 S. aureus isolates were analyzed. All strains were methicillin-susceptible S. aureus. We found a low prevalence of mupirocin and fusidic acid resistance (1.1% and 5.9%, respectively), but high levels of neomycin and bacitracin resistance (42.6% and 100%, respectively). Fusidic acid resistance was associated with more severe atopic dermatitis, demonstrated by higher EASI scores (median 17.8 vs 5.7, p=.009). Our results also corroborate the literature on the absence of cross-resistance between the aminoglycosides neomycin and gentamicin. Conclusions Our data, in a southern Brazilian sample of AD patients, revealed a low prevalence of mupirocin and fusidic acid resistance of S. aureus atopic eczema colonizer strains. However, for neomycin and bacitracin, which are commonly used topical antimicrobial drugs in Brazil, high levels of resistance were identified. Further restrictions on the use of these antimicrobials seem necessary to keep resistance as low as possible. PMID:27828633

  10. Staphylococcus aureus in locally produced white cheese in Tirana market

    Directory of Open Access Journals (Sweden)

    ELVIRA BELI

    2014-06-01

    Full Text Available Cheese has nutritional value, its consumption is very common in Albania, but is also excellent medium for bacterial growth, source of bacterial infection, particularly when it is produced from raw poor quality or unpasteurized milk. Microbial safety of cheeses may be enhanced by usage good quality raw milk, pasteurized milk, following GMP in aim to prevent cross-contamination. The aim of this study was to evaluate the presence and amount of Staphylococcus aureus in white cheeses, as an Albanian traditional product. Totally 120 samples of white cheese, produced in small big plant at different Albanian district, by raw milk or pasteurized milk, were collected from Tirana market. All samples were tested by phosphatase test to determine whether raw milk or pasteurized milk it was used for cheese production. 53/120 samples (44% resulted produced by pasteurized milk, 67/120 samples (56 % resulted produced by raw milk. The S. aureus was isolated in Baird Parker agar, and submitted to coagulase and API-staph test. Out of 120 cheese samples, 47 showed contamination by S. aureus coagulase-positive corresponding to 39.16%, otherwise 58 out of 120, 48.33 % of cheeses samples being contaminated with coagulase-negative strain of S. aureus. The occurrence S. aureus coagulase-positive in cheeses produced by pasteurized milk and raw milk it was respectively 7/53 (13.2 % and 40/67 (59.7%. 10% of the samples had high levels 105- 106cfu/g of S. aureus coagulase-positive, suggested that white cheese, may represent a health risk for the consumers

  11. Cavity Forming Pneumonia Due to Staphylococcus aureus Following Dengue Fever.

    Science.gov (United States)

    Miyata, Nobuyuki; Yoshimura, Yukihiro; Tachikawa, Natsuo; Amano, Yuichiro; Sakamoto, Yohei; Kosuge, Youko

    2015-11-01

    While visiting Malaysia, a 22-year-old previously healthy Japanese man developed myalgia, headache, and fever, leading to a diagnosis of classical dengue fever. After improvement and returning to Japan after a five day hospitalization, he developed productive cough several days after defervescing from dengue. Computed tomography (CT) thorax scan showed multiple lung cavities. A sputum smear revealed leukocytes with phagocytized gram-positive cocci in clusters, and grew an isolate Staphylococcus aureus sensitive to semi-synthetic penicillin; he was treated successfully with ceftriaxone and cephalexin. This second reported case of pneumonia due to S. aureus occurring after dengue fever, was associated both with nosocomial exposure and might have been associated with dengue-associated immunosuppression. Clinicians should pay systematic attention to bacterial pneumonia following dengue fever to establish whether such a connection is causally associated.

  12. Fluorescent reporters for markerless genomic integration in Staphylococcus aureus

    Science.gov (United States)

    de Jong, Nienke W. M.; van der Horst, Thijs; van Strijp, Jos A. G.; Nijland, Reindert

    2017-01-01

    We present integration vectors for Staphylococcus aureus encoding the fluorescent reporters mAmetrine, CFP, sGFP, YFP, mCherry and mKate. The expression is driven either from the sarA-P1 promoter or from any other promoter of choice. The reporter can be inserted markerless in the chromosome of a wide range of S. aureus strains. The integration site chosen does not disrupt any open reading frame, provides good expression, and has no detectable effect on the strains physiology. As an intermediate construct, we present a set of replicating plasmids containing the same fluorescent reporters. Also in these reporter plasmids the sarA-P1 promoter can be replaced by any other promoter of interest for expression studies. Cassettes from the replication plasmids can be readily swapped with the integration vector. With these constructs it becomes possible to monitor reporters of separate fluorescent wavelengths simultaneously. PMID:28266573

  13. A pig model of acute Staphylococcus aureus induced pyemia

    DEFF Research Database (Denmark)

    Nielsen, O. L.; Iburg, T.; Aalbæk, B.

    2009-01-01

    Background: Sepsis caused by Staphylococcus aureus constitutes an important cause of morbidity and mortality in humans, and the incidence of this disease-entity is increasing. In this paper we describe the initial microbial dynamics and lesions in pigs experimentally infected with S. aureus......, with the aim of mimicking human sepsis and pyemia. Methods: The study was conducted in anaesthetized and intravenously inoculated pigs, and was based on bacteriological examination of blood and testing of blood for IL-6 and C-reactive protein. Following killing of the animals and necropsy bacteriological...... and histological examinations of different organs were performed 4, 5 or 6 h after inoculation. Results: Clearance of bacteria from the blood was completed within the first 2 h in some of the pigs and the highest bacterial load was recorded in the lungs as compared to the spleen, liver and bones. This probably...

  14. An Aromatic Hydroxyamide Attenuates Multiresistant Staphylococcus aureus Toxin Expression.

    Science.gov (United States)

    Vomacka, Jan; Korotkov, Vadim S; Bauer, Bianca; Weinandy, Franziska; Kunzmann, Martin H; Krysiak, Joanna; Baron, Oliver; Böttcher, Thomas; Lorenz-Baath, Katrin; Sieber, Stephan A

    2016-01-26

    Methicillin-resistant Staphylococcus aureus (MRSA) causes severe infections with only few effective antibiotic therapies currently available. To approach this challenge, chemical entities with a novel and resistance-free mode of action are desperately needed. Here, we introduce a new hydroxyamide compound that effectively reduces the expression of devastating toxins in various S. aureus and MRSA strains. The molecular mechanism was investigated by transcriptome analysis as well as by affinity-based protein profiling. Down-regulation of several pathogenesis associated genes suggested the inhibition of a central virulence-related pathway. Mass spectrometry-based chemical proteomics revealed putative molecular targets. Systemic treatment with the hydroxyamide showed significant reduction of abscess sizes in a MRSA mouse skin infection model. The absence of resistance development in vitro further underlines the finding that targeting virulence could lead to prolonged therapeutic options in comparison to antibiotics that directly address bacterial survival.

  15. A pig model of acute Staphylococcus aureus induced pyemia

    DEFF Research Database (Denmark)

    Nielsen, O. L.; Iburg, T.; Aalbæk, B.;

    2009-01-01

    Background: Sepsis caused by Staphylococcus aureus constitutes an important cause of morbidity and mortality in humans, and the incidence of this disease-entity is increasing. In this paper we describe the initial microbial dynamics and lesions in pigs experimentally infected with S. aureus......, with the aim of mimicking human sepsis and pyemia. Methods: The study was conducted in anaesthetized and intravenously inoculated pigs, and was based on bacteriological examination of blood and testing of blood for IL-6 and C-reactive protein. Following killing of the animals and necropsy bacteriological...... was not detected in the blood and C-reactive protein did not increase, probably because of the short time course of the study. Conclusion: This study demonstrates the successful induction of acute pyemia (microabscesses), and forms a basis for future experiments that should include inoculation with strains of S...

  16. Staphylococcus aureus colonization related to severity of hand eczema.

    Science.gov (United States)

    Mernelius, S; Carlsson, E; Henricson, J; Löfgren, S; Lindgren, P-E; Ehricht, R; Monecke, S; Matussek, A; Anderson, C D

    2016-08-01

    Knowledge on Staphylococcus aureus colonization rates and epidemiology in hand eczema is limited. The aim of this study was to clarify some of these issues. Samples were collected by the "glove juice" method from the hands of 59 patients with chronic hand eczema and 24 healthy individuals. Swab samples were taken from anterior nares and throat from 43 of the 59 patients and all healthy individuals. S. aureus were spa typed and analysed by DNA-microarray-based genotyping. The extent of the eczema was evaluated by the hand eczema extent score (HEES). The colonization rate was higher on the hands of hand eczema patients (69 %) compared to healthy individuals (21 %, p eczema (HEES ≥ 13) had a significantly higher S. aureus density on their hands compared to those with milder eczema (HEES = 1 to 12, p = 0.004). There was no difference between patients and healthy individuals regarding colonization rates in anterior nares or throat. spa typing and DNA-microarray-based genotyping indicated certain types more prone to colonize eczematous skin. Simultaneous colonization, in one individual, with S. aureus of different types, was identified in 60-85 % of the study subjects. The colonization rate and density indicate a need for effective treatment of eczema and may have an impact on infection control in healthcare.

  17. Menaquinone biosynthesis potentiates haem toxicity in Staphylococcus aureus.

    Science.gov (United States)

    Wakeman, Catherine A; Hammer, Neal D; Stauff, Devin L; Attia, Ahmed S; Anzaldi, Laura L; Dikalov, Sergey I; Calcutt, M Wade; Skaar, Eric P

    2012-12-01

    Staphylococcus aureus is a pathogen that infects multiple anatomical sites leading to a diverse array of diseases. Although vertebrates can restrict the growth of invading pathogens by sequestering iron within haem, S. aureus surmounts this challenge by employing high-affinity haem uptake systems. However, the presence of excess haem is highly toxic, necessitating tight regulation of haem levels. To overcome haem stress, S. aureus expresses the detoxification system HrtAB. In this work, a transposon screen was performed in the background of a haem-susceptible, HrtAB-deficient S. aureus strain to identify the substrate transported by this putative pump and the source of haem toxicity. While a recent report indicates that HrtAB exports haem itself, the haem-resistant mutants uncovered by the transposon selection enabled us to elucidate the cellular factors contributing to haem toxicity. All mutants identified in this screen inactivated the menaquinone (MK) biosynthesis pathway. Deletion of the final steps of this pathway revealed that quinone molecules localizing to the cell membrane potentiate haem-associated superoxide production and subsequent oxidative damage. These data suggest a model in which membrane-associated haem and quinone molecules form a redox cycle that continuously generates semiquinones and reduced haem, both of which react with atmospheric oxygen to produce superoxide.

  18. Putative link between Staphylococcus aureus bacteriophage serotype and community association.

    Science.gov (United States)

    Mohamed, D H; Saberesheikh, S; Kearns, A M; Saunders, N A

    2012-07-01

    Methicillin-resistant Staphylococcus aureus (MRSA) from humans can be broadly separated into 3 groups: healthcare-associated (HA), community-associated (CA), and livestock-associated (LA) MRSA. Initially based on epidemiological features, division into these classes is becoming increasingly problematic. The sequencing of S. aureus genomes has highlighted variations in their accessory components, which likely account for differences in pathogenicity and epidemicity. In particular, temperate bacteriophages have been regarded as key players in bacterial pathogenesis. Bacteriophage-associated Panton-Valentine leukocidin genes (luk-PV) are regarded as epidemiological markers of the CA-MRSA due to their high prevalence in CA strains. This paper describes the development and application of a partial composite S. aureus virulence-associated gene microarray. Epidemic, pandemic, and sporadic lineages of UK HA and CA S. aureus were compared. Phage structural genes linked with CA isolates were identified and in silico analysis revealed these to be correlated with phage serogroup. CA strains predominantly carried a PVL-associated phage either of the A or Fb serogroup, whilst HA strains predominantly carried serogroup Fa or B phages. We speculate that carriage of a serogroup A/Fb PVL-associated phage rather than the luk-PV genes specifically is correlated with CA status.

  19. Superantigens in Staphylococcus aureus isolated from prosthetic joint infection

    Science.gov (United States)

    Kim, Choon K.; Karau, Melissa J.; Greenwood-Quaintance, Kerryl E.; Tilahun, Ashenafi Y.; David, Chella S.; Mandrekar, Jayawant N.; Patel, Robin; Rajagopalan, Govindarajan

    2014-01-01

    Staphylococcus aureus is a common cause of prosthetic joint infection (PJI). The prevalence of superantigens (SAgs) among PJI-associated S. aureus is unknown. Eighty-four S. aureus isolates associated with PJI isolated between 1999 and 2006 were studied. SAg genes, sea, seb, sec, sed, see, seg, seh, sei and tst, were assayed by PCR. Seventy-eight (92.9%) isolates carried at least one SAg gene studied, with 61 (72.6%) harboring more than one. seg was most commonly (70.2%) and seh was least frequently (4.8%) detected. tst-positive isolates were associated with early infection and increased ESR at diagnosis (P = 0.006 and P = 0.021, respectively). seg and sei were associated with methicillin resistance (P = 0.008 and 0.002, respectively). SAg genes are prevalent in S. aureus causing PJI; a majority of PJI-associated isolates produce biologically active SAgs in both planktonic and biofilm growth modes. PMID:25619753

  20. Human Staphylococcus aureus lineages among Zoological Park residents in Greece

    Directory of Open Access Journals (Sweden)

    E. Drougka

    2015-10-01

    Full Text Available Staphylococcus aureus is a part of the microbiota flora in many animal species. The clonal spread of S. aureus among animals and personnel in a Zoological Park was investigated. Samples were collected from colonized and infected sites among 32 mammals, 11 birds and eight humans. The genes mecA, mecC, lukF/lukS-PV (encoding Panton-Valentine leukocidin, PVL and tst (toxic shock syndrome toxin-1 were investigated by PCR. Clones were defined by Multilocus Sequence Typing (MLST, spa type and Pulsed-Field Gel Electrophoresis (PFGE. Seven S. aureus isolates were recovered from four animals and one from an employee. All were mecA, mecC and tst–negative, whereas, one carried the PVL genes and was isolated from an infected Squirrel monkey. Clonal analysis revealed the occurrence of seven STs, eight PFGE and five spa types including ones of human origin. Even though a variety of genotypes were identified among S. aureus strains colonizing zoo park residents, our results indicate that colonization with human lineages has indeed occurred.

  1. Staphylococcus aureus α toxin potentiates opportunistic bacterial lung infections.

    Science.gov (United States)

    Cohen, Taylor S; Hilliard, Jamese J; Jones-Nelson, Omari; Keller, Ashley E; O'Day, Terrence; Tkaczyk, Christine; DiGiandomenico, Antonio; Hamilton, Melissa; Pelletier, Mark; Wang, Qun; Diep, Binh An; Le, Vien T M; Cheng, Lily; Suzich, JoAnn; Stover, C Kendall; Sellman, Bret R

    2016-03-01

    Broad-spectrum antibiotic use may adversely affect a patient's beneficial microbiome and fuel cross-species spread of drug resistance. Although alternative pathogen-specific approaches are rationally justified, a major concern for this precision medicine strategy is that co-colonizing or co-infecting opportunistic bacteria may still cause serious disease. In a mixed-pathogen lung infection model, we find that the Staphylococcus aureus virulence factor α toxin potentiates Gram-negative bacterial proliferation, systemic spread, and lethality by preventing acidification of bacteria-containing macrophage phagosomes, thereby reducing effective killing of both S. aureus and Gram-negative bacteria. Prophylaxis or early treatment with a single α toxin neutralizing monoclonal antibody prevented proliferation of co-infecting Gram-negative pathogens and lethality while also promoting S. aureus clearance. These studies suggest that some pathogen-specific, antibody-based approaches may also work to reduce infection risk in patients colonized or co-infected with S. aureus and disparate drug-resistant Gram-negative bacterial opportunists.

  2. Strain Discrimination of Staphylococcus aureus Using Superantigen Profiles.

    Science.gov (United States)

    Tsen, Hau-Yang; Li, Sheng-Chih; Chiang, Yu-Cheng; Tsai, Shuo-Wen

    2016-01-01

    Staphylococcus aureus is one of the major bacterial species that may cause clinical infection and food-poisoning cases. Strains of this species may produce a series of superantigens (SAgs). Due to the importance of staphylococcal infections, reliable methods for the discrimination of strains of this species are important. Such data may allow us to trace the infection origins and be used for epidemiological study. For strain discrimination, genotyping methods, such as pulsed-field gel electrophoresis (PFGE), random amplified polymorphic DNA (RAPD), and multi-locus sequence typing (MLST), etc., could be used. Recently, toxin gene profiles, which can be used for the elucidation of the genetic and pathogenic relatedness between strains, also have been used to improve the strain discrimination. For S. aureus, as more SAg genes were discovered, the SAg profiles become more useful for the strain discrimination of S. aureus. In this chapter, a method for the discrimination of S. aureus strains using superantigen profiles will be described in detail.

  3. Staphylococcus aureus redirects central metabolism to increase iron availability.

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    David B Friedman

    2006-08-01

    Full Text Available Staphylococcus aureus pathogenesis is significantly influenced by the iron status of the host. However, the regulatory impact of host iron sources on S. aureus gene expression remains unknown. In this study, we combine multivariable difference gel electrophoresis and mass spectrometry with multivariate statistical analyses to systematically cluster cellular protein response across distinct iron-exposure conditions. Quadruplicate samples were simultaneously analyzed for alterations in protein abundance and/or post-translational modification state in response to environmental (iron chelation, hemin treatment or genetic (Deltafur alterations in bacterial iron exposure. We identified 120 proteins representing several coordinated biochemical pathways that are affected by changes in iron-exposure status. Highlighted in these experiments is the identification of the heme-regulated transport system (HrtAB, a novel transport system which plays a critical role in staphylococcal heme metabolism. Further, we show that regulated overproduction of acidic end-products brought on by iron starvation decreases local pH resulting in the release of iron from the host iron-sequestering protein transferrin. These findings reveal novel strategies used by S. aureus to acquire scarce nutrients in the hostile host environment and begin to define the iron and heme-dependent regulons of S. aureus.

  4. Synthesis and function of phospholipids in Staphylococcus aureus.

    Science.gov (United States)

    Kuhn, Sebastian; Slavetinsky, Christoph J; Peschel, Andreas

    2015-02-01

    Phospholipids are the major components of bacterial membranes, and changes in phospholipid composition affect important cellular processes such as metabolism, stress response, antimicrobial resistance, and virulence. The most prominent phospholipids in Staphylococcus aureus are phosphatidylglycerol, lysyl-phosphatidylglycerol, and cardiolipin, whose biosynthesis is mediated by a complex protein machinery. Phospholipid composition of the staphylococcal membrane has to be continuously adjusted to changing external conditions, which is achieved by a series of transcriptional and biochemical regulatory mechanisms. This mini-review outlines the current state of knowledge concerning synthesis, regulation, and function of the major staphylococcal phospholipids.

  5. Molecular mechanisms of methicillin resistance in Staphylococcus aureus.

    Science.gov (United States)

    Domínguez, M A; Liñares, J; Martín, R

    1997-09-01

    Methicillin-resistant Staphylococcus aureus (MRSA) strains are among the most common nosocomial pathogens. The most significant mechanism of resistance to methicillin in this-species is the acquisition of a genetic determinant (mecA gene). However, resistance seems to have a more complex molecular basis, since additional chromosomal material is involved in such resistance. Besides, overproduction of penicillinase and/or alterations in the PBPs can contribute to the formation of resistance phenotypes. Genetic and environmental factors leading to MRSA are reviewed.

  6. Pseudomembranous colitis secondary to methicillin-resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Pressly, Kalynn B; Hill, Emilie; Shah, Kairav J

    2016-05-10

    A 37-year-old woman with a history of type II diabetes and Crohn's disease, status postcholecystectomy, presented with a >2-week history of cramping abdominal pain, nausea, non-bloody/non-bilious emesis and, later, diarrhoea. A flexible sigmoidoscopy was performed, revealing that 'a segmental pseudomembrane was found from rectum to sigmoid colon'. Clostridium difficile PCR on the stool was repeated twice and resulted negative both times. A food history prior to onset of symptoms was consistent with Staphylococcal food poisoning and a stool culture was positive for heavy growth of methicillin-resistant Staphylococcus aureus and the absence of enteric flora. The patient was successfully treated with oral vancomycin.

  7. Antibacterial activity of alimentary plants against Staphylococcus aureus growth.

    Science.gov (United States)

    Pérez, C; Anesini, C

    1994-01-01

    Alimentary plants were screened for antibacterial activity against a penicillin G resistant strain of Staphylococcus aureus. Twenty-five samples of plant material corresponding to 21 species from 13 families were used. Both aqueous and ethanol extracts were obtained from them. Antibacterial activity was determined by the agar-well diffusion method, using cephazolin as a standard antibiotic. Seventeen ethanol extracts were found active. Eugenia caryophyllata (clavo de olor*) flowers, Myristica fragans (nuez moscada*) seeds, Theobroma cacao (cacao*) seed bark, Triticum sp (trigo*) fruit, Zea mays (maíz*) fruit and Piper nigrum (pimienta*) ripe fruit produced some of the more active extracts (* = Argentine vulgar names).

  8. Drugs resistance and penicillinase activity in skin isolated Staphylococcus aureus

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    Bhat K

    1990-01-01

    Full Text Available A study was carried out to evaluate the drug resistance pattern and penicillinase production in skin isolated Staphylococcus aurpus. The disk diffusion method showed prevalence of: multidrug resistance among S. aureus, strains, isolated from locafised skin abscesses. method for detection of penicilfinase could detect this enzyme m 98.60/o of the isolates all fo which were resistant to penicillin and ampicillin. C16xacillin resistance as detected by the agar dilution method was found in 1.4% of the isolates. On the whole cloxacillin and gentamy′cin were found to be the most effective ′antistaphylococcal antibotics.

  9. Pyrazole Based Inhibitors against Enzymes of Staphylococcus aureus

    DEFF Research Database (Denmark)

    Jagadeesan, G.; Vijayakuma, Vinodhkumar; Palayam, Malathy

    2015-01-01

    Pyrazole derivatives display a wide variety of biological activities such as antimicrobial, anti-inflammatory and anti-tumor activities. Its biological prominence has intrigued chemists and biologists in recent years to synthesize new pyrazole derivatives as antiviral, antibacterial and anticancer...... agents. The current study focuses on molecular docking and dynamics studies of pyrazole derivatives against Nucleosidase and DNA gyrase B of Staphylococcus aureus. Molecular docking and dynamics studies reveal that some of these derivatives show better binding abilities than some of the current drugs...

  10. Colonization of nursing professionals by Staphylococcus aureus La colonización de los profesionales de enfermería por Staphylococcus aureus A colonização dos profissionais de enfermagem por Staphylococcus aureus

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    Josely Pinto de Moura

    2011-04-01

    Full Text Available This cross-sectional study aimed to investigate the presence of Staphylococcus aureus in the saliva of the nursing team of a teaching hospital in the interior of São Paulo State. Three saliva samples were collected from 351 individuals with an interval of two months between each collection. All ethical aspects were considered. In 867 (82.3% cultures there was no identification of Staphylococcus aureus in the saliva, in 88 (17.7% cultures Staphylococcus aureus was isolated, 26 (2.5% of which were resistant to methicillin. The prevalence of professionals colonized by Staphylococcus aureus was 41.0% (144/351, of which 7.1% (25/351 were characterized as methicillin-resistant Staphylococcus aureus. Transient carriers represented 81.2% and persistent carriers 18.8%. Resistance to mupirocin was 73.1% of MRSA and 9.3% of MSSA. The results demonstrate that it is the nurse and nursing technician that are the professional categories most susceptible to MRSA. Broader discussion on the thematic and interventions are needed.Se trata de un estudio transversal que tuvo como objetivo investigar la presencia de Staphylococcus aureus en la saliva del equipo de enfermería de un hospital escuela del interior del estado de Sao Paulo. Fueron recolectadas tres muestras de saliva de 351 individuos con intervalo de dos meses. Todos los aspectos éticos fueron contemplados. En 867 (82,3% culturas no hubo identificación de Staphylococcus aureus en la saliva, en 88 (17,7% culturas fue aislado Staphylococcus aureus, siendo 26 (2,5% resistentes a la meticilina. La prevalencia de profesionales colonizados por Staphylococcus aureus fue de 41,0% (144/351, de los cuales 7,1% (25/351 fueron caracterizados como Staphylococcus aureus resistentes a la meticilina. Los portadores transitorios representaron 81,2% y los persistentes 18,8%. La resistencia a la mupirocina fue de 73,1% entre los resistentes a la meticilina y 9,3% en los sensibles a la meticilina. Los resultados

  11. Staphylococcus aureus detection in the mouth of housekeepers Detección de Staphylococcus aureus en la boca de trabajadores de la limpieza hospitalaria Detecção de Staphylococcus aureus na boca de trabalhadores da limpeza hospitalar

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    Elaine Drehmer de Almeida Cruz

    2011-02-01

    Full Text Available This study assessed the prevalence of colonization by Staphylococcus aureus in hospital housekeepers, and their knowledge and beliefs regarding this problem. Three saliva samples were collected and a questionnaire regarding knowledge and beliefs was applied. Of the 92 workers, 63 (68.5% participated in the study; 20 were not and 43 were colonized; 13 by methicillin resistant Staphylococcus aureus and 30 by methicillin sensitive Staphylococcus aureus. Persistent carrier status of methicillin resistant Staphylococcus aureus was detected in 15.4% of cases. Low knowledge and perception of occupational risk were observed. The mouth was identified as an important reservoir of methicillin resistant Staphylococcus aureus. Analyzing knowledge and beliefs, as well as the state of carrier, is an important strategy to be added to educational actions for the prevention of workers' colonization.Este estudio evaluó la prevalencia de la colonización por Staphylococcus aureus en trabajadores de limpieza hospitalaria, y su conocimiento y creencias acerca de la problemática. Fueron recolectadas tres muestras de saliva y aplicado un cuestionario referente al conocimiento y creencias. De 92 trabajadores, 63 (68,5% participaron del estudio; 20 se presentaron no colonizados y 43 colonizados; 13 para Staphylococcus aureus resistente a la meticilina y 30 para Staphylococcus aureus sensibles a la meticilina. El estado de portador persistente por Staphylococcus aureus resistente a la meticilina fue detectado en 15,4% de los casos. Bajo conocimiento y percepción del riesgo ocupacional fueron observados. La boca fue identificada como importante reservatorio de Staphylococcus aureus resistente a la meticilina. Analizar el conocimiento y creencias juntamente con la investigación del estado de portador es una importante estrategia a ser agregada a las acciones educativas para la prevención de la colonización de trabajadores.Este estudo avaliou a prevalência da coloniza

  12. Antibacterial Activity and Antibiotic-Enhancing Effects of Honeybee Venom against Methicillin-Resistant Staphylococcus aureus

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    Sang Mi Han

    2016-01-01

    Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA, along with other antibiotic resistant bacteria, has become a significant social and clinical problem. There is thus an urgent need to develop naturally bioactive compounds as alternatives to the few antibiotics that remain effective. Here we assessed the in vitro activities of bee venom (BV, alone or in combination with ampicillin, penicillin, gentamicin or vancomycin, on growth of MRSA strains. The antimicrobial activity of BV against MRSA strains was investigated using minimum inhibitory concentrations (MIC, minimum bactericidal concentrations (MBC and a time-kill assay. Expression of atl which encodes murein hydrolase, a peptidoglycan-degrading enzyme involved in cell separation, was measured by reverse transcription-polymerase chain reaction. The MICs of BV were 0.085 µg/mL and 0.11 µg/mL against MRSA CCARM 3366 and MRSA CCARM 3708, respectively. The MBC of BV against MRSA 3366 was 0.106 µg/mL and that against MRSA 3708 was 0.14 µg/mL. The bactericidal activity of BV corresponded to a decrease of at least 3 log CFU/g cells. The combination of BV with ampicillin or penicillin yielded an inhibitory concentration index ranging from 0.631 to 1.002, indicating a partial and indifferent synergistic effect. Compared to ampicillin or penicillin, both MRSA strains were more susceptible to the combination of BV with gentamicin or vancomycin. The expression of atl gene was increased in MRSA 3366 treated with BV. These results suggest that BV exhibited antibacterial activity and antibiotic-enhancing effects against MRSA strains. The atl gene was increased in MRSA exposed to BV, suggesting that cell division was interrupted. BV warrants further investigation as a natural antimicrobial agent and synergist of antibiotic activity.

  13. Sampling, prevalence and characterization of methicillin-resistant Staphylococcus aureus on two Belgian pig farms

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    Isabelle Dewaele

    2011-02-01

    Full Text Available This study investigated the spread of MRSA (methicillin-resistant Staphylococcus aureus on two Belgian pig farms. Pigs of different ages (from farrowing to slaughter age and sows as well as the barn environment were screened extensively on two occasions three months apart. A subset of MRSA isolates was tested for antimicrobial susceptibility to 16 antibiotics and was further characterized by pulsed-field gel electrophoresis. Ninety-five percent and 77% of the tested pigs on farm A and farm B, respectively, were colonized with MRSA. MRSA positive animals were detected in all age categories sampled on each sampling day. Piglets were already colonized in the farrowing unit with the same or other MRSA strains than their mother. The prevalence of MRSA colonized pigs increased significantly after weaning and decreased during the fattening period. Pigs carried MRSA mainly in the nares, followed by the perineum and skin and to a lesser degree the rectum. A pig could be contaminated or colonized with different MRSA strains at the same time. The barn environment was also found to be contaminated with different MRSA strains, including the air inlet and outlet. All isolates tested on both farms were resistant to both tetracycline and trimethoprim, while they were susceptible to rifampicin, mupirocin and linezolid. There was a significant difference in resistance prevalence between the two farms for the antibiotics gentamicin, kanamycin, tobramycin, tylosin, lincomycin and quinupristin/dalfopristin. Furthermore, several antibiotic resistance profiles were observed within one farm. This study clearly indicates that several MRSA strains circulate on one farm, from the nursery unit to the fattening unit. This is important to consider when attempts are made to remediate these farms.

  14. Synergistic action of gentamicin and bacteriophage in a continuous culture population of Staphylococcus aureus.

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    Amy E Kirby

    Full Text Available With the increasing frequency of antibiotic resistance and the decreasing frequency of new antibiotics entering the market, interest has returned to developing bacteriophage as a therapeutic agent. Acceptance of phage therapy, however, is limited by the unknown pharmacodynamics of a replicating agent, as well as the potential for the evolution of resistant bacteria. One way to overcome some of these limitations is to incorporate phage and antibiotics into a dual therapy regimen; however, this increases the complexity of the pharmacodynamics. The aim of this study is to develop an experimental system to evaluate the pharmacodynamics of dual phage-drug therapy. A continuous culture system for Staphylococcus aureus is used to simulate the pharmacokinetics of periodic antibiotic dosing alone and in combination with lytic phage. A computer model representation of the system allows further evaluation of the conditions governing the observed pharmacodynamics. The results of this experimental/modeling approach suggest that dual therapy can be more efficacious than single therapies, particularly if there is an overlap in the physiological pathways targeted by the individual agents. In this case, treatment with gentamicin induces a population of cells with a strong aggregation phenotype. These aggregators also have an increased ability to form biofilm, which is a well-known, non-genetic mechanism of drug resistance. However, the aggregators are also more susceptible than the parental strain to the action of the phage. Thus, dual treatment with gentamicin and phage resulted in lower final cell densities than either treatment alone. Unlike in the phage-only treatment, phage-resistant isolates were not detected in the dual treatment.

  15. Photodynamic inactivation of multidrug-resistant Staphylococcus aureus by chlorin e6 and red light (λ=670nm).

    Science.gov (United States)

    Winkler, Katrin; Simon, Carole; Finke, Melanie; Bleses, Katharina; Birke, Martina; Szentmáry, Nora; Hüttenberger, Dirk; Eppig, Timo; Stachon, Tanja; Langenbucher, Achim; Foth, Hans-Jochen; Herrmann, Mathias; Seitz, Berthold; Bischoff, Markus

    2016-09-01

    Multidrug-resistant Staphylococcus aureus (MDR-SA) are a frequent cause of antibiotic treatment refractory bacterial corneal infections. Photodynamic therapy (PDT) is being discussed as a putative treatment option to cure this type of bacterial infection. Here we tested the in vitro susceptibility of a set of 12 clinically derived MDR-SA isolates with differing genetic backgrounds and antibiotic resistance profiles against photodynamic inactivation (PDI) by the porphyrin chlorin e6 (Ce6) and red light (λ=670nm). All tested clinical isolates displayed a 5-log10 reduction in viable cells by Ce6 and red light, when cells were preincubated with the photosensitizer at concentrations ≥128μM for 30min in the dark, and a subsequent irradiation with light at λ=670nm (power density: 31mW/cm(2), absorbed dose: 18,6J/cm(2)) was applied. Similarly, cells of the laboratory strain Newman required the same Ce6 pre-incubation and light dose for a 5-log10 reduction in cell viability. Inactivation of crtM in strain Newman, which interferes with pigment production in S. aureus, rendered the mutant more susceptible to this PDT procedure, indicating that the level of resistance of S. aureus to this therapy form is affected by ability of the pathogen to produce the carotenoid pigment staphyloxanthin. Incubation of freshly explanted porcine corneas with a 0.5% Ce6 gel demonstrated that the photosensitizer can diffuse into and accumulate within the stroma of the cornea in concentrations found to be sufficient to yield a 5-log10 reduction of the S. aureus cell pool in vitro. These data suggest that PDI with Ce6 and red light might be a promising new option for the treatment of MDR-SA induced corneal infections.

  16. Staphylococcus aureus Small Colony Variants (SCVs: A Road Map for the Metabolic Pathways Involved in Persistent Infections

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    Richard Allan Proctor

    2014-07-01

    Full Text Available Persistent and relapsing infections, despite apparently adequate antibiotic therapy, occur frequently with many pathogens, but it is an especially prominent problem with Staphylococcus aureus infections. For the purposes of this review, persistence will encompass both of the concepts of long term survival within the host, including colonization, and the concept of resisting antibiotic therapy even when susceptible in the clinical microbiology laboratory. Over the past two decades, the mechanisms whereby bacteria achieve persistence are slowly being unraveled. S. aureus small colony variants (SCVs are linked to chronic, recurrent, and antibiotic-resistant infections, and the study of SCVs has contributed significantly to understanding of persistence. In our earlier work, defects in electron transport and thymidylate biosynthesis were linked to the development of the SCV phenotype (reviewed in 2006, thus this work will be discussed only briefly. Since 2006, it has been found that persistent organisms including SCVs are part of the normal life cycle of bacteria, and often they arise in response to harsh conditions, e.g., antibiotics, starvation, host cationic peptides. Many of the changes found in these early SCVs have provided a map for the discovery mechanisms (pathways for the development of persistent organisms. For example, changes in RNA processing, stringent response, toxin-antitoxin, ribosome protein L6 (RplF, and cold shock protein B (CspB found in SCVs are also found in other persisters. In addition, many classic persister organisms also show slow growth, hence SCVs. Recent work on S. aureus USA300 has elucidated the impact of aerobic expression of arginine deiminase genes on its ability to chronically colonize the skin and survive in abscesses. S. aureus SCVs also express arginine deiminase genes aerobically as well. Thus, many pathways found activated in electron transport type of SCVs are also increased in persisters that have intact

  17. Identification of putative drug targets in Vancomycin-resistant Staphylococcus aureus (VRSA) using computer aided protein data analysis.

    Science.gov (United States)

    Hasan, Md Anayet; Khan, Md Arif; Sharmin, Tahmina; Hasan Mazumder, Md Habibul; Chowdhury, Afrin Sultana

    2016-01-01

    Vancomycin-resistant Staphylococcus aureus (VRSA) is a Gram-positive, facultative aerobic bacterium which is evolved from the extensive exposure of Vancomycin to Methicillin resistant S. aureus (MRSA) that had become the most common cause of hospital and community-acquired infections. Due to the emergence of different antibiotic resistance strains, there is an exigency to develop novel drug targets to address the provocation of multidrug-resistant bacteria. In this study, in-silico genome subtraction methodology was used to design potential and pathogen specific drug targets against VRSA. Our study divulged 1987 proteins from the proteome of 34,549 proteins, which have no homologues in human genome after sequential analysis through CD-HIT and BLASTp. The high stringency analysis of the remaining proteins against database of essential genes (DEG) resulted in 169 proteins which are essential for S. aureus. Metabolic pathway analysis of human host and pathogen by KAAS at the KEGG server sorted out 19 proteins involved in unique metabolic pathways. 26 human non-homologous membrane-bound essential proteins including 4 which were also involved in unique metabolic pathway were deduced through PSORTb, CELLO v.2.5, ngLOC. Functional classification of uncharacterized proteins through SVMprot derived 7 human non-homologous membrane-bound hypothetical essential proteins. Study of potential drug target against Drug Bank revealed pbpA-penicillin-binding protein 1 and hypothetical protein MQW_01796 as the best drug target candidate. 2D structure was predicted by PRED-TMBB, 3D structure and functional analysis was also performed. Protein-protein interaction network of potential drug target proteins was analyzed by using STRING. The identified drug targets are expected to have great potential for designing novel drugs against VRSA infections and further screening of the compounds against these new targets may result in the discovery of novel therapeutic compounds that can be

  18. Caracterização de Staphylococcus aureus isolados da barra de mão de carrinhos e alças de cestas de supermercados

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    Daiane Buzzatto Oliveira

    2016-07-01

    Full Text Available Staphylococcus aureus é um dos agentes patogênicos mais notórios, sendo responsável por 45% das toxinfecções em todo o mundo. Um dos grandes problemas atuais é o desenvolvimento de cepas resistentes a antibióticos. Considerando a importância da disseminação desses micro-organismos na comunidade, o presente trabalho teve por objetivo determinar a presença de Staphylococcus aureus na barra de mão dos carrinhos e alças de cestas de supermercados da cidade de Campo Mourão - PR, e caracterizar a susceptibilidade dos isolados à oxacilina. Foram analisadas 120 amostras, sendo 60 coletadas das barras de mão de carrinhos e 60 coletadas das alças de cestas. Esse micro-organismo foi isolado em 75 amostras (62,5%, sendo que, desse total, 35 amostras (46,7% foram isoladas de carrinhos e 40 (53,3% de cestas de compras. As amostras positivas para Staphylococcus aureus foram submetidas aos testes de susceptibilidade, pelo método de disco-difusão, à oxacilina (cefoxitina e todas as amostras foram consideradas sensíveis a essa droga. Constatou que as barras de mãos e as alças de cestas de supermercados, podem ser consideradas como fômites, na disseminação de Staphylococcus aureus, sendo de extrema importância a higienização desses objetos, a fim de diminuir os riscos de contaminação na comunidade.Palavras-chave: Staphylococcus aureus. Contaminação. Superfícies. Oxacilina. ABSTRACTCharacterization of Staphylococcus aureus Isolated of shopping carts hand bars and handles of handheld shopping baskets in supermarketsStaphylococcus aureus is one of the most notorious pathogens, accounting for 45% of intoxications worldwide. One of the major problems today is the development of antibiotic-resistant strains. Considering the importance of dissemination of these micro- organisms in the community, this study aimed to determine the presence of Staphylococcus aureus in shopping carts hand bars and handles of handheld shopping baskets in

  19. Chamaecyparis obtusa Essential Oil Inhibits Methicillin-Resistant Staphylococcus aureus Biofilm Formation and Expression of Virulence Factors.

    Science.gov (United States)

    Kim, Eun-Sook; Kang, Sun-Young; Kim, Young-Hoi; Lee, Young-Eun; Choi, Na-Young; You, Yong-Ouk; Kim, Kang-Ju

    2015-07-01

    The emergence of antibiotic-resistant bacteria has caused difficulty in treating infectious diseases. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most commonly recognized antibiotic-resistant bacteria. Novel antibiotics are urgently required to treat these bacteria. Raw materials derived from natural sources can be used for the development of novel antibiotics, such as Chamaecyparis obtusa (C. obtusa), which has been traditionally used in treating asthmatic disease. In this study, the antibacterial activity of the essential oil (EO) extracted from C. obtusa leaves against MRSA was investigated. MRSA growth and acid production from glucose metabolism were inhibited at concentrations greater than 0.1 mg/mL C. obtusa EO. MRSA biofilm formation was observed using scanning electron microscopy and safranin staining. C. obtusa EO inhibited MRSA biofilm formation at concentrations greater than 0.1 mg/mL. Using real-time polymerase chain reaction, mRNA expression of virulence factor genes, sea, agrA, and sarA, was observed. agrA expression was inhibited with C. obtusa EO concentrations greater than 0.2 mg/mL, whereas inhibition of sea and sarA expression was also observed at a concentration of 0.3 mg/mL. C. obtusa EO was analyzed by gas chromatography (GC) and GC coupled for mass spectrometry, which identified 59 constituents, accounting to 98.99% of the total EO. These findings suggest that C. obtusa EO has antibacterial effects against MRSA, which might be associated with the major components of C. obtusa EO, such as sabinene (19.06%), α-terpinyl acetate (16.99%), bornyl acetate (10.48%), limonene (8.54%), elemol (7.47%), myrcene (5.86%), γ-terpinene (4.04%), and hibaene (3.01%).

  20. Community-Acquired Methicillin-Resistant "Staphylococcus aureus": Considerations for School Nurses

    Science.gov (United States)

    Alex, Aniltta; Letizia, MariJo

    2007-01-01

    Methicillin-resistant "Staphylococcus aureus" (MRSA) is a disease-causing organism that has been present in hospital settings since the 1960s. However, a genetically distinct strain of MRSA, called community-acquired methicillin-resistant "Staphylococcus aureus" (CA-MRSA), has emerged in recent years in community settings among healthy…

  1. Staphylococcus aureus and Staphylococcus epidermidis Virulence Strains as Causative Agents of Persistent Infections in Breast Implants.

    Directory of Open Access Journals (Sweden)

    Daniela Chessa

    Full Text Available Staphylococcus epidermidis and Staphylococcus aureus are currently considered two of the most important pathogens in nosocomial infections associated with catheters and other medical implants and are also the main contaminants of medical instruments. However because these species of Staphylococcus are part of the normal bacterial flora of human skin and mucosal surfaces, it is difficult to discern when a microbial isolate is the cause of infection or is detected on samples as a consequence of contamination. Rapid identification of invasive strains of Staphylococcus infections is crucial for correctly diagnosing and treating infections. The aim of the present study was to identify specific genes to distinguish between invasive and contaminating S. epidermidis and S. aureus strains isolated on medical devices; the majority of our samples were collected from breast prostheses. As a first step, we compared the adhesion ability of these samples with their efficacy in forming biofilms; second, we explored whether it is possible to determine if isolated pathogens were more virulent compared with international controls. In addition, this work may provide additional information on these pathogens, which are traditionally considered harmful bacteria in humans, and may increase our knowledge of virulence factors for these types of infections.

  2. Response of Staphylococcus Aureus to a Spaceflight Analogue

    Science.gov (United States)

    Castro, S. L.; Ott, C. M.

    2010-01-01

    The decreased gravity of the spaceflight environment creates quiescent, low fluid shear conditions. This environment can impart considerable effects on the physiology of microorganisms as well as their interactions with potential hosts. Using the rotating wall vessel (RWV), as a spaceflight analogue, the consequence of low fluid shear culture on microbial pathogenesis has provided a better understanding of the risks to the astronaut crew from infectious microorganisms. While the outcome of low fluid shear culture has been investigated for several bacterial pathogens, little has been done to understand how this environmental factor affects Staphylococcus aureus. S. aureus is an opportunistic human pathogen which presents a high level of infection risk to the crew, as it has been isolated from both the space shuttle and International Space Station. Given that approximately forty percent of the population are carriers of the bacteria, eradication of this organism from in flight environments is impractical. These reasons have lead to us to assess the response of S. aureus to a reduced fluid shear environment. Culture in the RWV demonstrated that S. aureus grown under the low-shear condition had lower cell concentrations after 10 hours when compared to the control culture. Furthermore, the low-shear cultured bacteria displayed a reduction in carotenoid production, pigments responsible for their yellow/gold coloration. When exposed to various environmental stressors, post low-shear culture, a decrease in the ability to survive oxidative assault was observed compared to control cultures. The low fluid shear environment also resulted in a decrease in hemolysin secretion, a staphylococcal toxin responsible for red blood cell lysis. When challenged by the immune components present in human whole blood, low-shear cultured S. aureus demonstrated significantly reduced survival rates as compared to the control culture. Assays to determine the duration of these alterations

  3. Staphylococcus pseudintermedius expresses surface proteins that closely resemble those from Staphylococcus aureus.

    Science.gov (United States)

    Geoghegan, Joan A; Smith, Emma J; Speziale, Pietro; Foster, Timothy J

    2009-09-18

    Staphylococcus pseudintermedius is a commensal of dogs that is implicated in the pathogenesis of canine pyoderma. This study aimed to determine if S. pseudintermedius expresses surface proteins resembling those from Staphylococcus aureus and to characterise them. S. pseudintermedius strain 326 was shown to adhere strongly to purified fibrinogen, fibronectin and cytokeratin 10. It adhered to the alpha-chain of fibrinogen which, along with binding to cytokeratin 10, is the hallmark of clumping factor B of S. aureus, a surface protein that is in part responsible for colonisation of the human nares. Ligand-affinity blotting with cell-wall extracts demonstrated that S. pseudintermedius 326 expressed a cell-wall anchored fibronectin binding protein which recognised the N-terminal 29kDa fragment. The ability to bind fibronectin is an important attribute of pathogenic S. aureus and is associated with the ability of S. aureus to colonise skin of human atopic dermatitis patients. S. pseudintermedius genomic DNA was probed with labelled DNA amplified from the serine-aspartate repeat encoding region of clfA of S. aureus. This probe hybridised to a single SpeI fragment of S. pseudintermedius DNA. In the cell-wall extract of S. pseudintermedius 326, a 180kDa protein was discovered which bound to fibrinogen by ligand-affinity blotting and reacted in a Western blot with antibodies raised against the serine-aspartate repeat region of ClfA and the B-repeats of SdrD of S. aureus. It is proposed that this is an Sdr protein with B-repeats that has an A domain that binds to fibrinogen. Whether it is the same protein that binds cytokeratin 10 is not clear.

  4. Emergence of vancomycin resistant Staphylococcus aureus (VRSA from a tertiary care hospital from northern part of India

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    Sen Malay

    2006-10-01

    Full Text Available Abstract Background Glycopeptides such as vancomycin are frequently the antibiotics of choice for the treatment of infections caused by methicillin resistant Staphylococcus aureus (MRSA. For the last 7 years incidence of vancomycin intermediate S. aureus and vancomycin resistant S. aureus (VISA and VRSA respectively has been increasing in various parts of the world. The present study was carried out to find out the presence of VISA and VRSA in the northern part of India. Methods A total 1681 staphylococcal isolates consisting of 783 S. aureus and 898 coagulase negative staphylococci (CoNS were isolated from different clinical specimens from various outpatient departments and wards. All S. aureus and 93 CoNS were subjected to MIC testing (against vancomycin, teicolplanin and oxacillin; Brain Heart Infusion (BHI vancomycin screen agar test; disc diffusion testing, and PCR for mecA, vanA and vanB genes detection. Results Out of 783 S. aureus two S. aureus strains were found to be vancomycin and teicoplanin resistant (one strain with MIC 32 μg/ml and the other strain with MIC 64 μg/ml; six strains of S. aureus have shown to be vancomycin intermediate (two strains with MIC 16 μg/ml and four strains with MIC 8 μg/ml; and two strains with teicoplanin intermediate (MIC 16 μg/ml. One CoNS strain was resistant to vancomycin and teicoplanin (MIC 32 μg/ml, and two CoNS strains were intermediate to vancomycin and teicoplanin (MIC 16 μg/ml. All VRSA, VISA and vancomycin resistant CoNS had shown growth on BHI vancomycin screen agar (vancomycin 6 μg/ml and were mecA PCR positive. None of these isolates have demonstrated vanA/vanB gene by PCR. Conclusion The present study reveals for the first time emergence of VISA/VRSA from this part of world and indicates the magnitude of antibiotic resistance in and around the study area. The major cause of this may be unawareness and indiscriminate use of broad-spectrum antibiotics.

  5. Heme Recognition By a Staphylococcus Aureus IsdE

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    Grigg, J.C.; Vermeiren, C.L.; Heinrichs, D.E.; Murphy, M.E.P.

    2009-06-03

    Staphylococcus aureus is a Gram-positive bacterial pathogen and a leading cause of hospital acquired infections. Because the free iron concentration in the human body is too low to support growth, S. aureus must acquire iron from host sources. Heme iron is the most prevalent iron reservoir in the human body and a predominant source of iron for S. aureus. The iron-regulated surface determinant (Isd) system removes heme from host heme proteins and transfers it to IsdE, the cognate substrate-binding lipoprotein of an ATP-binding cassette transporter, for import and subsequent degradation. Herein, we report the crystal structure of the soluble portion of the IsdE lipoprotein in complex with heme. The structure reveals a bi-lobed topology formed by an N- and C-terminal domain bridged by a single {alpha}-helix. The structure places IsdE as a member of the helical backbone metal receptor superfamily. A six-coordinate heme molecule is bound in the groove established at the domain interface, and the heme iron is coordinated in a novel fashion for heme transporters by Met{sup 78} and His{sup 229}. Both heme propionate groups are secured by H-bonds to IsdE main chain and side chain groups. Of these residues, His{sup 299} is essential for IsdE-mediated heme uptake by S. aureus when growth on heme as a sole iron source is measured. Multiple sequence alignments of homologues from several other Gram-positive bacteria, including the human pathogens pyogenes, Bacillus anthracis, and Listeria monocytogenes, suggest that these other systems function equivalently to S. aureus IsdE with respect to heme binding and transport.

  6. Characterization of a mouse-adapted Staphylococcus aureus strain.

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    Silva Holtfreter

    Full Text Available More effective antibiotics and a protective vaccine are desperately needed to combat the 'superbug' Staphylococcus aureus. While in vivo pathogenicity studies routinely involve infection of mice with human S. aureus isolates, recent genetic studies have demonstrated that S. aureus lineages are largely host-specific. The use of such animal-adapted S. aureus strains may therefore be a promising approach for developing more clinically relevant animal infection models. We have isolated a mouse-adapted S. aureus strain (JSNZ which caused a severe outbreak of preputial gland abscesses among male C57BL/6J mice. We aimed to extensively characterize this strain on a genomic level and determine its virulence potential in murine colonization and infection models. JSNZ belongs to the MLST type ST88, rare among human isolates, and lacks an hlb-converting phage encoding human-specific immune evasion factors. Naive mice were found to be more susceptible to nasal and gastrointestinal colonization with JSNZ than with the human-derived Newman strain. Furthermore, naïve mice required antibiotic pre-treatment to become colonized with Newman. In contrast, JSNZ was able to colonize mice in the absence of antibiotic treatment suggesting that this strain can compete with the natural flora for space and nutrients. In a renal abscess model, JSNZ caused more severe disease than Newman with greater weight loss and bacterial burden. In contrast to most other clinical isolates, JSNZ can also be readily genetically modified by phage transduction and electroporation. In conclusion, the mouse-adapted strain JSNZ may represent a valuable tool for studying aspects of mucosal colonization and for screening novel vaccines and therapies directed at preventing colonization.

  7. Population structure of Staphylococcus aureus from remote African Babongo Pygmies.

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    Frieder Schaumburg

    Full Text Available BACKGROUND: Pandemic community-acquired methicillin-resistant Staphylococcus aureus isolates (CA-MRSA predominantly encode the Panton-Valentine leukocidin (PVL, which can be associated with severe infections. Reports from non-indigenous Sub-Saharan African populations revealed a high prevalence of PVL-positive isolates. The objective of our study was to investigate the S. aureus carriage among a remote indigenous African population and to determine the molecular characteristics of the isolates, particularly those that were PVL-positive. METHODOLOGY/PRINCIPAL FINDINGS: Nasal S. aureus carriage and risk factors of colonization were systematically assessed in remote Gabonese Babongo Pygmies. Susceptibility to antibiotics, possession of toxin-encoding genes (i.e., PVL, enterotoxins, and exfoliative toxins, S. aureus protein A (spa types and multi-locus sequence types (MLST were determined for each isolate. The carriage rate was 33%. No MRSA was detected, 61.8% of the isolates were susceptible to penicillin. Genes encoding PVL (55.9%, enterotoxin B (20.6%, exfoliative toxin D (11.7% and the epidermal cell differentiation inhibitor B (11.7% were highly prevalent. Thirteen spa types were detected and were associated with 10 STs predominated by ST15, ST30, ST72, ST80, and ST88. CONCLUSIONS: The high prevalence of PVL-positive isolates among Babongo Pygmies demands our attention as PVL can be associated with necrotinzing infection and may increase the risk of severe infections in remote Pygmy populations. Many S. aureus isolates from Babongo Pygmies and pandemic CA-MRSA-clones have a common genetic background. Surveillance is needed to control the development of resistance to antibiotic drugs and to assess the impact of the high prevalence of PVL in indigenous populations.

  8. Methicillin-resistant Staphylococcus aureus (mrsa) in a Malaysian hospital.

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    Cheong, I; Tan, S C; Wong, Y H; Zainudin, B M; Rahman, M Z

    1994-03-01

    Between August 1990 to November 1991, 905 of 2583 (35.4%) isolates of Staphylococcus aureus were found to be methicillin-resistant in a general hospital in Malaysia. A detailed study of 539 of these isolates showed a high prevalence of methicillin resistant Staphylococcus aureus (MRSA) in the surgical/orthopaedic wards, paediatric wards and the special care unit. The yield of MRSA was highest from wounds/ulcers/skin swabs accounting for 64.2 per cent followed by 6.9 per cent in blood cultures. Vancomycin remains the drug of choice with no resistance detected. The resistance to ciprofloxacin was 6.7 per cent, rifampicin 4.5 per cent and fusidic acid 2.0 per cent. Most isolates were resistant to aminoglycosides. In view of the high prevalence of MRSA in this hospital, the authorities must introduce more effective measures to control its spread as a nosocomial pathogen. Otherwise it may seriously disrupt the efficient delivery of health care services in the country.

  9. Antimicrobial blue light inactivation of Methicillin-resistant Staphylococcus aureus

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    Wang, Yucheng; Dai, Tianhong; Gu, Ying

    2016-10-01

    Background: With the increasing emergence of multidrug-resistant (MDR) bacterial strains, there is a pressing need for the development of alternative treatment for infections. Antimicrobial blue light (aBL) has provided a simple and effective approach. Methods: We first investigated the effectiveness of aBL (415 nm) inactivation of USA300 LAClux (a communityacquired Methicillin-resistant Staphylococcus aureus strain) both in the planktonic and biofilm forms. The survival of the bacteria in suspensions was determined by serial dilution and that of the biofilm-embedded bacteria was determined by bioluminescence quantification. Using a mouse model of thermal burn infected with USA300 LAClux, we further assessed the effectiveness of aBL for treating localized infections. Bioluminescence imaging was performed to monitor in real time bacterial viability in vivo. Results: In vitro study showed that, for the planktonic counterpart of the bacteria or the 24-h-old biofilms, an irradiance of 55 mW/cm2 for 60 min resulted in a 4.61 log10 or 2.56 log10 inactivation, respectively. In vivo study using infected mouse burns demonstrated that a 2.56-log10 inactivation was achieved after 100-mW/cm2 irradiation for 62 min. Conclusions: aBL is a potential alternative approach for treating Methicillin-resistant Staphylococcus aureus infections.

  10. Staphylococcus aureus entrance into the dairy chain: Tracking S. aureus from dairy cow to cheese

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    Judith Kümmel

    2016-10-01

    Full Text Available Staphylococcus aureus is one of the most important contagious mastitis pathogens in dairy cattle. Due to its zoonotic potential, control of S. aureus is not only of great economic importance in the dairy industry but also a significant public health concern. The aim of this study was to decipher the potential of bovine udder associated S. aureus as reservoir for S. aureus contamination in dairy production and processing. From 18 farms, delivering their milk to an alpine dairy plant for the production of smeared semi-hard and hard cheese. 1176 quarter milk (QM samples of all cows in lactation (n = 294 and representative samples form bulk tank milk (BTM of all farms were surveyed for coagulase positive (CPS and coagulase negative Staphylococci (CNS. Furthermore, samples from different steps of the cheese manufacturing process were tested for CPS and CNS. As revealed by chemometric-assisted FTIR spectroscopy and molecular subtyping (spa typing and multi locus sequence typing, dairy cattle represent indeed an important, yet underreported, entrance point of S. aureus into the dairy chain. Our data clearly show that certain S. aureus subtypes are present in primary production as well as in the cheese processing at the dairy plant. However, although a considerable diversity of S. aureus subtypes was observed in QM and BTM at the farms, only certain S. aureus subtypes were able to enter and persist in the cheese manufacturing at the dairy plant and could be isolated from cheese until day fourteen of ripening. Farm strains belonging to the FTIR cluster B1 and B3, which show genetic characteristics (t2953, ST8, enterotoxin profile: sea/sed/sej of the recently described S. aureus genotype B, most successfully contaminated the cheese production at the dairy plant. Thus our study fosters the hypothesis that genotype B S. aureus represent a specific challenge in control of S. aureus in the dairy chain that requires effective clearance strategies and hygienic

  11. Staphylococcus aureus Entrance into the Dairy Chain: Tracking S. aureus from Dairy Cow to Cheese

    Science.gov (United States)

    Kümmel, Judith; Stessl, Beatrix; Gonano, Monika; Walcher, Georg; Bereuter, Othmar; Fricker, Martina; Grunert, Tom; Wagner, Martin; Ehling-Schulz, Monika

    2016-01-01

    Staphylococcus aureus is one of the most important contagious mastitis pathogens in dairy cattle. Due to its zoonotic potential, control of S. aureus is not only of great economic importance in the dairy industry but also a significant public health concern. The aim of this study was to decipher the potential of bovine udder associated S. aureus as reservoir for S. aureus contamination in dairy production and processing. From 18 farms, delivering their milk to an alpine dairy plant for the production of smeared semi-hard and hard cheese. one thousand hundred seventy six one thousand hundred seventy six quarter milk (QM) samples of all cows in lactation (n = 294) and representative samples form bulk tank milk (BTM) of all farms were surveyed for coagulase positive (CPS) and coagulase negative Staphylococci (CNS). Furthermore, samples from different steps of the cheese manufacturing process were tested for CPS and CNS. As revealed by chemometric-assisted FTIR spectroscopy and molecular subtyping (spa typing and multi locus sequence typing), dairy cattle represent indeed an important, yet underreported, entrance point of S. aureus into the dairy chain. Our data clearly show that certain S. aureus subtypes are present in primary production as well as in the cheese processing at the dairy plant. However, although a considerable diversity of S. aureus subtypes was observed in QM and BTM at the farms, only certain S. aureus subtypes were able to enter and persist in the cheese manufacturing at the dairy plant and could be isolated from cheese until day 14 of ripening. Farm strains belonging to the FTIR cluster B1 and B3, which show genetic characteristics (t2953, ST8, enterotoxin profile: sea/sed/sej) of the recently described S. aureus genotype B, most successfully contaminated the cheese production at the dairy plant. Thus, our study fosters the hypothesis that genotype B S. aureus represent a specific challenge in control of S. aureus in the dairy chain that requires

  12. Eliminação de resistência a drogas por fluorquinolonas em Staphylococcus aureus de origem bovina Elimination of resistance to drugs by fluoroquinolones in bovine strains of Staphylococcus aureus

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    Maria S.V. Pereira

    2004-03-01

    Full Text Available Cepas de Staphylococcus aureus de origem bovina foram submetidas ao tratamento com quatro fluoquinolonas na concentração subinibitória (1/2 x CMI, para avaliar a influência desses agentes sobre plasmídios. A ciprofloxacina mostrou ser a fluorquinolona mais eficiente, eliminando marcas de resistência para estreptomicina, tetraciclina, penicilina e cádmio. A norfloxacina e a pefloxacina eliminaram resistência para penicilina e tetraciclina, respectivamente; no entanto, não foi evidenciada a eliminação de plasmídio com ofloxacina. Os resultados confirmam a eficácia das fluor-quinolonas em eliminar plasmídios de resistência mostrando a importância desses estudos como contribuição para o entendimento da prevenção de linhagens multiresistentes, uma vez que as quinolonas em concentrações subinibitórias podem aumentar a sensibilidade das linhagens a outros agentes antimicrobianos.Bovine strains of Staphylococcus aureus were submitted to treatment with four fluoro-quinolones in subinhibitory concentrations (1/2 x MICs to evaluate their influence on the curing of plasmids. Ciprofloxacin showed to be the most efficient by eliminating resistance to streptomycin, tetracyclin, penicillin, and cadmium nitrate. Norfloxacin and pefloxacin eliminated penicillin- and tetracyclin-resistance respectively. Otherwise, plasmids elimination by ofloxacin was not evidenced. The results obtained in this study confirm the potential of fluoroquinolones to eliminate antibiotic-resistant plasmids, and showed to be a valuable contribution for the prevention of multi-resistant strains, and may even enhance their sensitivity to other chemotherapeutic agents.

  13. Proteome changes of Caenorhabditis elegans upon a Staphylococcus aureus infection

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    Schoofs Liliane

    2010-02-01

    Full Text Available Abstract Background The success of invertebrates throughout evolution is an excellent illustration of the efficiency of their defence strategies. Caenorhabditis elegans has proven to be an appropriate model for transcriptome studies of host-pathogen interactions. The aim of this paper is to complement this knowledge by investigating the worm's response to a Staphylococcus aureus infection through a 2-dimensional differential proteomics approach. Results Different types of growth media in combination with either E. coli OP50 or Staphylococcus aureus were tested for an effect on the worm's lifespan. LB agar was chosen and C. elegans samples were collected 1 h, 4 h, 8 h and 24 h post S. aureus infection or E. coli incubation. Proteomics analyses resulted in the identification of 130 spots corresponding to a total of 108 differentially expressed proteins. Conclusions Exploring four time-points discloses a dynamic insight of the reaction against a gram-positive infection at the level of the whole organism. The remarkable upregulation after 8 h and 24 h of many enzymes involved in the citric acid cycle might illustrate the cost of fighting off an infection. Intriguing is the downregulation of chaperone molecules, which are presumed to serve a protective role. A comparison with a similar experiment in which C. elegans was infected with the gram-negative Aeromonas hydrophila reveals that merely 9% of the identified spots, some of which even exhibiting an opposite regulation, are present in both studies. Hence, our findings emphasise the complexity and pathogen-specificity of the worm's immune response and form a firm basis for future functional research. Reviewers This article was reviewed by Itai Yanai, Dieter Wolf and Torben Luebke (nominated by Walter Lutz.

  14. Detection of enterotoxigenic Staphylococcus aureus isolates in domestic dairy products

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    HR Tavakoli

    2010-12-01

    Full Text Available Background and objectives: Staphylococcus aureusis a one of THE most frequent causes of food poisoning (FP in dairy products. The main etiologic agents of FP are staphylococcal enterotoxins (SE. There are different types of SE; types A (SEA and B (SEB are the most clinically important enterotoxins. Traditional dairy products are still produced in small batches and sold by some vendors without a permit from the Ministry of Health. This study focuses on the molecular and serological detection of enterotoxigenic Staphylococcus aureus SEA and SEB genes and its products, respectively from samples of such traditional products."nMaterials and Methods: 100 samples from dairy products were produced under sterile conditions via traditional methods and were transported to the laboratory. The samples were cultured and identified by routine bacteriological methods. The isolated bacteria were evaluated by PCR tests for detection of the genes encoding SEA and SEB. Subsequently, the ability of these strains to produce enterotoxin was examined by Sac's culture method and was confirmed by Sigel Radial Immounodiffussion (SRID."nResults: The results indicated that 32% of the dairy products were contaminated by S. aureus (cream 18% , cheese 10%, milk 4%. The PCR results showed that 15.6% of the S. aureus isolates possessed the SEA gene, 9.3% had the SEB gene, and 6.2% possessed both genes. The evaluation of enterotoxin production indicated that 80% of SEA and 33% of SEB genes were expressed."nConclusion: Enterotoxins SEA and SEB are heat stable and consequently; heating has no effect on dairy products contaminated by entertoxins. Subsequently, gastritis may occur within several hours after consumption. Our findings suggest that PCR is a rapid, sensitive, specific, and inexpensive method for detecting SE and can replace the traditional assays.

  15. Preventing Staphylococcus aureus Bacteremia and Sepsis in Patients With Staphylococcus aureus Colonization of Intravascular Catheters A Retrospective Multicenter Study and Meta-Analysis

    NARCIS (Netherlands)

    Hetem, David J.; de Ruiter, Susanne C.; Buiting, Anton G. M.; Kluytmans, Jan A. J. W.; Thijsen, Steven F.; Vlaminckx, Bart J. M.; Wintermans, Robert G. F.; Bonten, Marc J. M.; Ekkelenkamp, Miquel B.

    2011-01-01

    Two previous studies in tertiary care hospitals identified Staphylococcus aureus colonization of intravascular (IV) catheters as a strong predictor of subsequent S. aureus bacteremia (SAB), even in the absence of clinical signs of systemic infection. Bacteremia was effectively prevented by timely an

  16. In Vitro Susceptibility of Methicillin-Resistant Staphylococcus aureus and Methicillin-Susceptible Staphylococcus aureus to a New Antimicrobial, Copper Silicate▿

    OpenAIRE

    2007-01-01

    The soluble copper silicate (CS) MIC of 100 strains of methicillin-resistant Staphylococcus aureus and 100 strains of methicillin-susceptible S. aureus (MSSA) was 175 mg Cu/liter. Bactericidal and postantibiotic effects (≥1 h) were seen at 2× MIC and 4× MIC. The frequency of mutation was

  17. Improved lux reporters for use in Staphylococcus aureus.

    Science.gov (United States)

    Mesak, Lili Rosana; Yim, Grace; Davies, Julian

    2009-05-01

    The use of luxABCDE (lux) offers certain advantages over other reporters, such as: lacZ and xylE. It is real time and its signal generation is produced without the requirement for any additional substrates. In some bacteria such as Staphylococcus spp, light production by luciferase is restricted because of a limited availability of endogenous substrates such as fatty acid aldehyde. We describe the construction of promoterless-lux cloning vectors, pGYlux and pAmilux. S. aureus carrying B. subtilis xyl/tetO promoter fused to the lux genes of pGYlux gave up to a 2.5-fold enhancement of luminescence over S. aureus carrying the xyl/tetO promoter fused to lux genes of the previously published parent vector pAL2. Furthermore, pAmilux showed a 6-fold enhancement of lux expression when compared to pGYlux in S. aureus. This was achieved by cloning the constitutive ami promoter upstream of the luxCDE genes to increase endogenous fatty acid aldehyde production while maintaining its reporter functionality by fusing promoters to the luxAB genes.

  18. Persister formation in Staphylococcus aureus is associated with ATP depletion

    Energy Technology Data Exchange (ETDEWEB)

    Conlon, Brian P.; Rowe, Sarah E.; Gandt, Autumn Brown; Nuxoll, Austin S.; Donegan, Niles P.; Zalis, Eliza A.; Clair, Geremy; Adkins, Joshua N.; Cheung, Ambrose L.; Lewis, Kim

    2016-04-18

    Persisters are dormant phenotypic variants of bacterial cells that are tolerant to killing by antibiotics1. Persisters are associated with chronic bacterial infection and antibiotic treatment failure. In Escherichia coli, toxin/antitoxin (TA) modules are responsible for persister formation. The mechanism of persister formation in Gram positive bacteria is unknown. Staphylococcus aureus is a major human pathogen, responsible for a variety of chronic and relapsing infections such as osteomyelitis, endocarditis and infections of implanted devices. Deleting TA modules in S. aureus did not affect the level of persisters. Here we show that S. aureus persisters are produced due to a stochastic entrance to stationary phase accompanied by a drop in intracellular ATP. Cells expressing stationary state markers are present throughout the growth phase, increasing in frequency with cell density. Cell sorting revealed that expression of stationary markers was associated with a 100-1000 fold increased likelihood of survival to antibiotic challenge. We find that the antibiotic tolerance of these cells is due to a drop in intracellular ATP. The ATP level of the cell is predictive of bactericidal antibiotic efficacy and explains bacterial tolerance to antibiotic treatment.

  19. Tea tree oil-induced transcriptional alterations in Staphylococcus aureus.

    Science.gov (United States)

    Cuaron, Jesus A; Dulal, Santosh; Song, Yang; Singh, Atul K; Montelongo, Cesar E; Yu, Wanqin; Nagarajan, Vijayaraj; Jayaswal, Radheshyam K; Wilkinson, Brian J; Gustafson, John E

    2013-03-01

    Tea tree oil (TTO) is a steam distillate of Melaleuca alternifolia that demonstrates broad-spectrum antibacterial activity. This study was designed to document how TTO challenge influences the Staphylococcus aureus transcriptome. Overall, bioinformatic analyses (S. aureus microarray meta-database) revealed that both ethanol and TTO induce related transcriptional alterations. TTO challenge led to the down-regulation of genes involved with energy-intensive transcription and translation, and altered the regulation of genes involved with heat shock (e.g. clpC, clpL, ctsR, dnaK, groES, groEL, grpE and hrcA) and cell wall metabolism (e.g. cwrA, isaA, sle1, vraSR and vraX). Inactivation of the heat shock gene dnaK or vraSR which encodes a two-component regulatory system that responds to peptidoglycan biosynthesis inhibition led to an increase in TTO susceptibility which demonstrates a protective role for these genes in the S. aureus TTO response. A gene (mmpL) encoding a putative resistance, nodulation and cell division efflux pump was also highly induced by TTO. The principal antimicrobial TTO terpene, terpinen-4-ol, altered ten genes in a transcriptional direction analogous to TTO. Collectively, this study provides additional insight into the response of a bacterial pathogen to the antimicrobial terpene mixture TTO.

  20. Biochemical characters and antibiotic susceptibility of Staphylococcus aureus isolates

    Institute of Scientific and Technical Information of China (English)

    Subhankari Prasad Chakraborty; Santanu Kar Mahapatra; Somenath Roy

    2011-01-01

    Objective: To observe the biochemical characters and antibiotic susceptibility of isolated Staphylococcus aureus (S. auerus) strains against some conventional and traditional antibiotics.Methods:Bacterial culture was done in Mueller-Hinton broth at 37 ℃. Characters of these strains were determined by traditional biochemical tests such as hydrolysis test of gelatin, urea, galactose, starch and protein, and fermentation of lactose and sucrose. Antibiotic susceptibility were carried out by minimum inhibitory concentration test, minium bactericidal concentration test, disc agar diffusion test and brain heart infusion oxacillin screening agar. Results: From this study, it was observed that 100% S. aureus isolates showed positive results in gelatin, urea and galactose hydrolysis test, 50% isolates were positive in starch hydrolysis test, 35% in protein hydrolysis test, 100% isolates in lactose fermenting test, but no isolate was positive in sucrose fermenting test. Antibiotic susceptibility testing suggested that 20% of isolates were resistant to kanamycin and 46.67% were resistant to oxacillin. Conclusions: These findings show that all these isolates have gelatin, urea, galactose hydrolysis and lactose fermenting activity. 20% of these isolates were resistant to kanamycin and 46.67% were resistant to oxacillin. Thirty post operative pathogenic isolated S. aureus strains were used in this study.

  1. Necroptosis Promotes Staphylococcus aureus Clearance by Inhibiting Excessive Inflammatory Signaling

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    Kipyegon Kitur

    2016-08-01

    Full Text Available Staphylococcus aureus triggers inflammation through inflammasome activation and recruitment of neutrophils, responses that are critical for pathogen clearance but are associated with substantial tissue damage. We postulated that necroptosis, cell death mediated by the RIPK1/RIPK3/MLKL pathway, would function to limit pathological inflammation. In models of skin infection or sepsis, Mlkl−/− mice had high bacterial loads, an inability to limit interleukin-1b (IL-1b production, and excessive inflammation. Similarly, mice treated with RIPK1 or RIPK3 inhibitors had increased bacterial loads in a model of sepsis. Ripk3−/− mice exhibited increased staphylococcal clearance and decreased inflammation in skin and systemic infection, due to direct effects of RIPK3 on IL-1b activation and apoptosis. In contrast to Casp1/4−/− mice with defective S. aureus killing, the poor outcomes of Mlkl−/− mice could not be attributed to impaired phagocytic function. We conclude that necroptotic cell death limits the pathological inflammation induced by S. aureus.

  2. Rot is a key regulator of Staphylococcus aureus biofilm formation

    Science.gov (United States)

    Mootz, Joe M.; Benson, Meredith A.; Heim, Cortney E.; Crosby, Heidi A.; Kavanaugh, Jeffrey S.; Dunman, Paul M.; Kielian, Tammy; Torres, Victor J.; Horswill, Alexander R.

    2015-01-01

    AUTHOR SUMMARY Staphylococcus aureus is a significant cause of chronic biofilm infections on medical implants. We investigated the biofilm regulatory cascade and discovered that the repressor of toxins (Rot) is part of this pathway. A USA300 community-associated methicillin-resistant S. aureus (CA-MRSA) strain deficient in Rot was unable to form a biofilm using multiple different assays, and we found rot mutants in other strain lineages were also biofilm deficient. By performing a global analysis of transcripts and protein production controlled by Rot, we observed that all the secreted protease genes were upregulated in a rot mutant, and we hypothesized that this regulation could be responsible for the biofilm phenotype. To investigate this question, we determined that Rot bound to the protease promoters, and we observed that activity levels of these enzymes, in particular the cysteine proteases, were increased in a rot mutant. By inactivating these proteases, biofilm capacity was restored to the mutant, demonstrating they are responsible for the biofilm negative phenotype. Finally, we tested the rot mutant in a mouse catheter model of biofilm infection and observed a significant reduction in biofilm burden. Thus S. aureus uses the transcription factor Rot to repress secreted protease levels in order to build a biofilm. PMID:25612137

  3. Inhibitory effects of antibiofilm compound 1 against Staphylococcus aureus biofilms.

    Science.gov (United States)

    Shrestha, Looniva; Kayama, Shizuo; Sasaki, Michiko; Kato, Fuminori; Hisatsune, Junzo; Tsuruda, Keiko; Koizumi, Kazuhisa; Tatsukawa, Nobuyuki; Yu, Liansheng; Takeda, Kei; Sugai, Motoyuki

    2016-03-01

    A novel benzimidazole molecule that was identified in a small-molecule screen and is known as antibiofilm compound 1 (ABC-1) has been found to prevent bacterial biofilm formation by multiple bacterial pathogens, including Staphylococcus aureus, without affecting bacterial growth. Here, the biofilm inhibiting ability of 156 μM ABC-1 was tested in various biofilm-forming strains of S. aureus. It was demonstrated that ABC-1 inhibits biofilm formation by these strains at micromolar concentrations regardless of the strains' dependence on Polysaccharide Intercellular Adhesin (PIA), cell wall-associated protein dependent or cell wall- associated extracellular DNA (eDNA). Of note, ABC-1 treatment primarily inhibited Protein A (SpA) expression in all strains tested. spa gene disruption showed decreased biofilm formation; however, the mutants still produced more biofilm than ABC-1 treated strains, implying that ABC-1 affects not only SpA but also other factors. Indeed, ABC-1 also attenuated the accumulation of PIA and eDNA on cell surface. Our results suggest that ABC-1 has pleotropic effects on several biofilm components and thus inhibits biofilm formation by S. aureus.

  4. Clonal complex 398 methicillin susceptible Staphylococcus aureus: a frequent unspecialized human pathogen with specific phenotypic and genotypic characteristics.

    Directory of Open Access Journals (Sweden)

    Tomasz Chroboczek

    Full Text Available Clonal complex 398 livestok-associated-MRSA (CC398 LA-MRSA clone is described as a major animal pathogen that can also colonize and infect humans. CC398 methicillin susceptible Staphylococcus aureus (CC398 MSSA is less described. We identified 126 CC398 MSSA strains of human origin within 6380 S. aureus isolates gathered between 2009 and 2011, from the French National Reference Centre for Staphylococci. They were characterized using antimicrobial susceptibility testing, spa typing, DNA microarrays (Identibac S. aureus Genotyping ®, Alere, CC398-specific sequence PCR, ermT (encoding macrolides résistance PCR. Fifty-three CC398 LA-MRSA collected from French pigs and veal were used as comparators, and phylogenetic relations between human CC398 MSSA and animal CC398 MRSA populations were explored on the basis of spa-typing and DNA microarrays. CC398 MSSA were able to induce a large spectrum of infections (especially skin, bloodstream, and pneumonias. The prevalence rate of this clone was high in MSSA population, i.e., 24.7% in a local prospective study on nasal colonization, and 7.5% in a national prospective study on infective endocarditis. CC398 MSSA isolates were frequently (89% erythromycin resistant, due to the presence of the ermT gene, a gene not detected in erythromycin resistant CC398 LA-MRSA strains. Expression of staphylococcal complement inhibitor (scn and the chemotaxis inhibitory protein (chp, was also specific to this population. The CC398 MRSA signature included also a panel of antibiotic resistance genes, especially a type IV or V cassette mec and tetM. CC398 MSSA and CC398 LA-MRSA populations were closely related based on spa-typing and DNA microarrays, with the MRSA strains forming the most derived lineage in phylogenic trees. Both MSSA and MRSA populations may come from common ancestors, which would have evolved in the settings of different selective pressures, explaining the acquisition of ermT, chp and scn for MSSA, and

  5. Familial Clustering of Staphylococcus aureus Bacteremia in First-Degree Relatives

    DEFF Research Database (Denmark)

    Oestergaard, Louise B.; Christiansen, Mia N.; Schmiegelow, Michelle D.

    2016-01-01

    BACKGROUND: A genetic predisposition to Staphylococcus aureus bacteremia has been demonstrated in animals, suggesting that genetic differences might influence susceptibility to S aureus in humans. OBJECTIVE: To determine whether a history of S aureus bacteremia in first-degree relatives increases...

  6. Long-term cortisol levels are not associated with nasal carriage of Staphylococcus aureus

    NARCIS (Netherlands)

    L. Manenschijn (Laura); A.M. Jetten; W.J.B. van Wamel (Willem); M. Tavakol (Mehri); E.L.T. van den Akker (Erica); J.W. Koper (Jan); A.F. van Belkum (Alex); E.F.C. van Rossum (Liesbeth)

    2012-01-01

    textabstractStaphylococcus aureus (S. aureus) colonizes the anterior nares in part of the population and the persistent carrier state is associated with increased infection risk. Knowledge concerning the determinants of S. aureus nasal carriage is limited. Previously, we found that glucocorticoid re

  7. Antibiotic-mediated selection of quorum-sensing-negative Staphylococcus aureus

    DEFF Research Database (Denmark)

    Paulander, Wilhelm Erik Axel; Varming, Anders Nissen; Bæk, Kristoffer Torbjørn;

    2012-01-01

    -acquired S. aureus infections and suggest that the adaptability of S. aureus to antibiotics involves the agr locus. IMPORTANCE: Staphylococcus aureus is the most frequently isolated pathogen in intensive care units and a common cause of nosocomial infections, resulting in a high degree of morbidity...

  8. The molecular changing mechanism of Ampicillin-Sulbactam resistant Staphylococcus aureus towards Methicillin resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Mieke Hemiawati Satari

    2005-12-01

    Full Text Available The aim of this study was to determine the molecular changing of S.aureus, which is resistant to Ampicillin-Sulbactam and then become resistant to Methicillin as a result of improper dosage. The study was conducted by isolating Ampicillin-Sulbactam resistant and Methicillin Resistant S.aureus (MRSA, afterwards an amplification process was performed by PCR (Polymerase Chain Reaction. to isolate the betalactamase enzyme regulator and PBP 2a genes. The result of this research showed that there were a deletion of few amino acids from the regulator gene, and a suspicion that the DNA sequence had been substituted from PBP 2 gene into PBP 2a (gen mec. This process had formed MRSA.

  9. Surgimiento y diseminación de Staphylococcus aureus meticilinorresistente Staphylococcus aureus methicillin-resistant: emergence and dissemination

    Directory of Open Access Journals (Sweden)

    Maria Elena Velázquez-Meza

    2005-10-01

    Full Text Available Las infecciones nosocomiales ocasionadas por cepas de Staphylococcus aureus meticilinorresistentes (SAMR son un problema de salud importante en todo el mundo. Este microorganismo produce una gran variedad de infecciones incluyendo osteomielitis, endocarditis invasora, artritis séptica y septicemia. La multirresistencia es un factor que influye en la persistencia de los SAMR dentro del ámbito hospitalario. La introducción de técnicas de tipificación molecular dentro de las investigaciones epidemiológicas ha provisto nuevas herramientas para conocer el origen y las vías de diseminación de este microorganismo. Una de las conclusiones importantes que han surgido de este tipo de estudios es que un número pequeño de clonas son las responsables de las infecciones estafilocócicas en todo el mundo.Nosocomial infections due to methicillin-resistant Staphylococcus aureus (MRSA is an important health problem worldwide. This microorganism causes a variety of clinical infections, including osteomyelitis, invasive endocarditis, septic arthritis and septicemia. Antimicrobial resistance is a factor that influences the persistence of MRSA in the hospital environment. The introduction of molecular typing techniques in epidemiological investigations has provided new tools for identifying the microorganism's origin and routes of dissemination. One of the most important conclusions that have resulted from these types of studies is that a small number of clones are responsible for most of the staphylococcal infections throughout the world.

  10. Antibiotic surgical prophylaxis increases nasal carriage of antibiotic-resistant staphylococci.

    Science.gov (United States)

    McMurray, Claire L; Hardy, Katherine J; Verlander, Neville Q; Hawkey, Peter M

    2015-12-01

    Staphylococci are a significant cause of hospital-acquired infection. Nasal carriage of Staphylococcus aureus is an important risk factor for infection in surgical patients and coagulase-negative staphylococci (CNS) are a major cause of prosthetic joint infections. The impact that antibiotic surgical prophylaxis has on the nasal carriage of staphylococci has not been studied. Daily nasal swabs were taken from 63 patients who received antibiotic surgical prophylaxis and 16 patients who received no antibiotics. Total aerobic bacterial count, S. aureus and CNS were enumerated by culture from nasal swabs. Representative isolates were typed by staphylococcal interspersed repeat units (SIRU) typing and PFGE, and MICs to nine antibiotics were determined. After antibiotic administration, there was a reduction in S. aureus counts (median - 2.3 log(10)c.f.u. ml(- 1)) in 64.0 % of S. aureus carriers, compared with only a 0.89 log(10)c.f.u. ml(- 1) reduction in 75.0 % of S. aureus carriers who did not receive antibiotics. A greater increase in the nasal carriage rate of meticillin-resistant CNS was observed after antibiotic surgical prophylaxis compared with hospitalization alone, with increases of 16.4 and 4.6 %, respectively. Antibiotic-resistant S. epidermidis carriage rate increased by 16.6 % after antibiotic administration compared with 7.5 % with hospitalization alone. Antibiotic surgical prophylaxis impacts the nasal carriage of both S. aureus and CNS.

  11. Small Changes in Environmental Parameters Lead to Alterations in Antibiotic Resistance, Cell Morphology and Membrane Fatty Acid Composition in Staphylococcus lugdunensis

    OpenAIRE

    Crompton, Marcus J; R Hugh Dunstan; Macdonald, Margaret M.; Johan Gottfries; Christof von Eiff; Timothy K Roberts

    2014-01-01

    Staphylococcus lugdunensis has emerged as a major cause of community-acquired and nosocomial infections. This bacterium can rapidly adapt to changing environmental conditions to survive and capitalize on opportunities to colonize and infect through wound surfaces. It was proposed that S. lugdunensis would have underlying alterations in metabolic homeostasis to provide the necessary levels of adaptive protection. The aims of this project were to examine the impacts of subtle variations in envi...

  12. Mammary Gland Pathology Subsequent to Acute Infection with Strong versus Weak Biofilm Forming Staphylococcus aureus Bovine Mastitis Isolates: A Pilot Study Using Non-Invasive Mouse Mastitis Model

    Science.gov (United States)

    Gogoi-Tiwari, Jully; Williams, Vincent; Waryah, Charlene Babra; Costantino, Paul; Al-Salami, Hani; Mathavan, Sangeetha; Wells, Kelsi; Tiwari, Harish Kumar; Hegde, Nagendra; Isloor, Shrikrishna; Al-Sallami, Hesham; Mukkur, Trilochan

    2017-01-01

    Background Biofilm formation by Staphylococcus aureus is an important virulence attribute because of its potential to induce persistent antibiotic resistance, retard phagocytosis and either attenuate or promote inflammation, depending upon the disease syndrome, in vivo. This study was undertaken to evaluate the potential significance of strength of biofilm formation by clinical bovine mastitis-associated S. aureus in mammary tissue damage by using a mouse mastitis model. Methods Two S. aureus strains of the same capsular phenotype with different biofilm forming strengths were used to non-invasively infect mammary glands of lactating mice. Biofilm forming potential of these strains were determined by tissue culture plate method, ica typing and virulence gene profile per detection by PCR. Delivery of the infectious dose of S. aureus was directly through the teat lactiferous duct without invasive scraping of the teat surface. Both bacteriological and histological methods were used for analysis of mammary gland pathology of mice post-infection. Results Histopathological analysis of the infected mammary glands revealed that mice inoculated with the strong biofilm forming S. aureus strain produced marked acute mastitic lesions, showing profuse infiltration predominantly with neutrophils, with evidence of necrosis in the affected mammary glands. In contrast, the damage was significantly less severe in mammary glands of mice infected with the weak biofilm-forming S. aureus strain. Although both IL-1β and TNF-α inflammatory biomarkers were produced in infected mice, level of TNF-α produced was significantly higher (p<0.05) in mice inoculated with strong biofilm forming S. aureus than the weak biofilm forming strain. Conclusion This finding suggests an important role of TNF-α in mammary gland pathology post-infection with strong biofilm-forming S. aureus in the acute mouse mastitis model, and offers an opportunity for the development of novel strategies for reduction of

  13. Prevalence of Staphylococcus aureus Nasal Carriage in Human Immunodeficiency Virus-Infected and Uninfected Children in Botswana: Prevalence and Risk Factors.

    Science.gov (United States)

    Reid, Michael J A; Fischer, Rebecca S B; Mannathoko, Naledi; Muthoga, Charles; McHugh, Erin; Essigmann, Heather; Brown, Eric L; Steenhoff, Andrew P

    2017-02-06

    Staphylococcus aureus is an important cause of morbidity and mortality in children in sub-Saharan Africa (SSA). A major risk factor for staphylococcal infection is S. aureus colonization of the anterior nares. We sought to define risk factors for S. aureus carriage and characterize antimicrobial resistance patterns in children in Botswana. A cross-sectional study was conducted at two clinical sites in southern Botswana. Patients under 18 years of age underwent two nasal swabs and brief interviews, 4 weeks apart. Standard microbiological techniques were used. For persistent carriers, S. aureus was isolated from swabs at both time points, and for intermittent carriers, S. aureus was isolated from only one swab. Poisson regression with robust variance estimator was used to compare prevalence of carriage and the resistance phenotypes. Among 56 enrollees, prevalence of S. aureus colonization was 55% (N = 31), of whom 42% (N = 13) were persistent carriers. Of human immunodeficiency virus-infected children, 64% (N = 9) were carriers. Risk factors for nasal carriage included a history of tuberculosis (prevalence ratio [PR] = 1.60; 95% confidence interval [CI] = 1.02, 2.51; P = 0.040) and closer proximity to health care (PR = 0.89; 95% CI = 0.80, 0.99; P = 0.048). Prior pneumonia was more common among persistent rather than intermittent carriers (PR = 2.64; 95% CI = 1.64, 4.23; P < 0.001). Methicillin-resistant S. aureus (MRSA) prevalence was 13%. Of isolates tested, 16% were resistant to three or more drugs (N = 7/44). In summary, children in southern Botswana are frequently colonized with S. aureus Antibiotic resistance, especially MRSA, is also widespread. Antibiotic recommendations for treatment of staphylococcal infections in SSA should take cognizance of these resistance patterns.

  14. Antibiotic Resistance Questions and Answers

    Science.gov (United States)

    ... on the Farm Get Smart About Antibiotics Week Antibiotic Resistance Questions and Answers Language: English Español (Spanish) ... a los antibióticos Questions about Bacteria, Viruses, and Antibiotics Q: What are bacteria and viruses? A: Bacteria ...

  15. Graphene oxide-silver nanocomposite as a promising biocidal agent against methicillin-resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    de Moraes ACM

    2015-11-01

    Full Text Available Ana Carolina Mazarin de Moraes,1 Bruna Araujo Lima,2 Andreia Fonseca de Faria,1 Marcelo Brocchi,2 Oswaldo Luiz Alves1 1Laboratory of Solid State Chemistry, Institute of Chemistry, University of Campinas, Campinas, São Paulo, Brazil; 2Department of Genetics, Evolution and Bioagents, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil Background: Methicillin-resistant Staphylococcus aureus (MRSA has been responsible for serious hospital infections worldwide. Nanomaterials are an alternative to conventional antibiotic compounds, because bacteria are unlikely to develop microbial resistance against nanomaterials. In the past decade, graphene oxide (GO has emerged as a material that is often used to support and stabilize silver nanoparticles (AgNPs for the preparation of novel antibacterial nanocomposites. In this work, we report the synthesis of the graphene-oxide silver nanocomposite (GO-Ag and its antibacterial activity against relevant microorganisms in medicine. Materials and methods: GO-Ag nanocomposite was synthesized through the reduction of silver ions (Ag+ by sodium citrate in an aqueous GO dispersion, and was extensively characterized using ultraviolet-visible absorption spectroscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. The antibacterial activity was evaluated by microdilution assays and time-kill experiments. The morphology of bacterial cells treated with GO-Ag was investigated via transmission electron microscopy. Results: AgNPs were well distributed throughout GO sheets, with an average size of 9.4±2.8 nm. The GO-Ag nanocomposite exhibited an excellent antibacterial activity against methicillin-resistant S. aureus, Acinetobacter baumannii, Enterococcus faecalis, and Escherichia coli. All (100% MRSA cells were inactivated after 4 hours of exposure to GO-Ag sheets. In addition, no toxicity was found for either pristine GO or bare Ag

  16. Applying Convergent Immunity to Innovative Vaccines Targeting Staphylococcus aureus

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    Michael R Yeaman

    2014-09-01

    Full Text Available Recent perspectives forecast a new paradigm for future 3rd generation vaccines based on commonalities found in diverse pathogens or convergent immune defenses to such pathogens. For Staphylococcus aureus, recurring infections and a limited success of vaccines containing S. aureus antigens imply that native antigens induce immune responses insufficient for optimal efficacy. These perspectives exemplify the need to apply novel vaccine strategies to high priority pathogens. One such approach can be termed convergent immunity, where antigens from non-target organisms that contain epitope homologues found in the target organism are applied in vaccines. This approach aims to evoke atypical immune defenses via synergistic processes that 1 afford protective efficacy; 2 target an epitope from one organism that contributes to protective immunity against another; 3 cross-protect against multiple pathogens occupying a common anatomic or immunologic niche; and/or 4 overcome immune subversion or avoidance strategies of target pathogens. Thus, convergent immunity has a potential to promote protective efficacy not usually elicited by native antigens from a target pathogen. Variations of this concept have been mainstays in the history of viral and bacterial vaccine development. A more far-reaching example is the pre–clinical evidence that specific fungal antigens can induce cross-kingdom protection against bacterial pathogens. This trans-kingdom protection has been demonstrated in preclinical studies of the recombinant Candida albicans agglutinin-like sequence 3 protein (rAls3 where it was shown that a vaccine containing rAls3 provides homologous protection against C. albicans, heterologous protection against several other Candida species, and convergent protection against several strains of S. aureus. Convergent immunity reflects an intriguing new approach to designing and developing vaccine antigens and is considered here in the context of vaccines to target

  17. Global distribution and diversity of ovine-associated Staphylococcus aureus.

    Science.gov (United States)

    Smith, Edward M; Needs, Polly F; Manley, Grace; Green, Laura E

    2014-03-01

    Staphylococcus aureus is an important pathogen of many species, including sheep, and impacts on both human and animal health, animal welfare, and farm productivity. Here we present the widest global diversity study of ovine-associated S. aureus to date. We analysed 97 S. aureus isolates from sheep and sheep products from the UK, Turkey, France, Norway, Australia, Canada and the USA using multilocus sequence typing (MLST) and spa typing. These were compared with 196 sheep isolates from Europe (n=153), Africa (n=28), South America (n=14) and Australia (n=1); 172 bovine, 68 caprine and 433 human S. aureus profiles. Overall there were 59 STs and 87 spa types in the 293 ovine isolates; in the 97 new ovine isolates there were 22 STs and 37 spa types, including three novel MLST alleles, four novel STs and eight novel spa types. Three main CCs (CC133, CC522 and CC700) were detected in sheep and these contained 61% of all isolates. Four spa types (t002, t1534, t2678 and t3576) contained 31% of all isolates and were associated with CC5, CC522, CC133 and CC522 respectively. spa types were consistent with MLST CCs, only one spa type (t1403) was present in multiple CCs. The three main ovine CCs have different but overlapping patterns of geographical dissemination that appear to match the location and timing of sheep domestication and selection for meat and wool production. CC133, CC522 and CC700 remained ovine-associated following the inclusion of additional host species. Ovine isolates clustered separately from human and bovine isolates and those from sheep cheeses, but closely with caprine isolates. As with cattle isolates, patterns of clonal diversification of sheep isolates differ from humans, indicative of their relatively recent host-jump.

  18. Distribution of food-borne Staphylococcus aureus enterotoxin genes.

    Science.gov (United States)

    Hu, W D

    2016-01-29

    We identified and analyzed 5 new-type enterotoxin genes, including SEj, SEl, SEq, SEm, and SEr, to explore the distribution of 5 enterotoxin genes in Staphylococcus aureus of different origins as well as their correlations and differences. We examined the distribution of the S. aureus enterotoxin genes and their pathogenic mechanisms. A total of 660 specimens were collected from January 2011 to December 2014, and 217 strains of S. aureus were isolated. The template DNA of S. aureus was extracted. The Primer6.0 and Oligo7 software were used to design and synthesize polymerase chain reaction primers. Amplification results were analyzed by electrophoresis, and the amplification products were recovered and sequenced. Thirty-six bacterial strains contained the SEj gene (16.6%), including 15, 8, 8, 4, and 1 strains in fresh meat, quick-frozen food, raw milk, human purulent tissue, and living environment, respectively. Thirty-one bacterial strains contained the SEr gene (14.3%), including 16, 9, and 6 strains in fresh meat, quick-frozen food, and raw milk, respectively. Twenty-one bacterial strains contained the enterotoxin SEq gene (9.7%), including 8, 6, 6, and 1 strains in fresh meat, quick-frozen food, raw milk, and human purulent tissue, respectively. No SEm and SEl genes were detected. Different types of foods carry different types of enterotoxins, providing a basis for quick tracing for food poisoning. Three enterotoxin genes, SEj, SEr, and SEq, showed the highest carrier rate in quick-frozen food. It is imperative to improve their detection in quick-frozen food.

  19. Shedding of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus from adult and pediatric bathers in marine waters

    Directory of Open Access Journals (Sweden)

    Sinigalliano Christopher D

    2011-01-01

    Full Text Available Abstract Background Staphylococcus aureus including methicillin resistant S. aureus, MRSA, are human colonizing bacteria that commonly cause opportunistic infections primarily involving the skin in otherwise healthy individuals. These infections have been linked to close contact and sharing of common facilities such as locker rooms, schools and prisons Waterborne exposure and transmission routes have not been traditionally associated with S. aureus infections. Coastal marine waters and beaches used for recreation are potential locations for the combination of high numbers of people with close contact and therefore could contribute to the exposure to and infection by these organisms. The primary aim of this study was to evaluate the amount and characteristics of the shedding of methicillin sensitive S. aureus, MSSA and MRSA by human bathers in marine waters. Results Nasal cultures were collected from bathers, and water samples were collected from two sets of pools designed to isolate and quantify MSSA and MRSA shed by adults and toddlers during exposure to marine water. A combination of selective growth media and biochemical and polymerase chain reaction analysis was used to identify and perform limited characterization of the S. aureus isolated from the water and the participants. Twelve of 15 MRSA isolates collected from the water had identical genetic characteristics as the organisms isolated from the participants exposed to that water while the remaining 3 MRSA were without matching nasal isolates from participants. The amount of S. aureus shed per person corresponded to 105 to 106 CFU per person per 15-minute bathing period, with 15 to 20% of this quantity testing positive for MRSA. Conclusions This is the first report of a comparison of human colonizing organisms with bacteria from human exposed marine water attempting to confirm that participants shed their own colonizing MSSA and MRSA into their bathing milieu. These findings clearly

  20. Prevalence of Multiple Antibiotic Resistant Infections in Diabetic versus Nondiabetic Wounds

    Directory of Open Access Journals (Sweden)

    Urvish Trivedi

    2014-01-01

    Full Text Available Diabetes mellitus (DM affects 23.6 million people in the USA and approximately 20–25% of diabetic patients will develop foot ulceration during the course of their disease. Up to a quarter of these patients will develop infections that will necessitate amputation. Although many studies report that the rates of antibiotic resistant infections have increased dramatically in the DM population over the last decade, to our knowledge there have been no reports directly comparing the rates of antibiotic resistant infections in DM versus non-DM wounds. We performed a retrospective study comparing the wound infections of 41 DM patients to those of 74 non-DM patients to test the hypothesis that infections with multidrug resistant organisms (MDRO were more prevalent in the DM population. We found that 63.4% of DM and 50% of non-DM patients had MDRO infections, which was not statistically different. However, 61% of the DM patients had Pseudomonas infections compared to only 18.9% of non-DM patients. Furthermore, DM patients had significantly more coinfections with both Pseudomonas and Staphylococcus aureus. Though our initial hypothesis was incorrect, we demonstrated a significant correlation between Pseudomonas and Pseudomonas/S. aureus coinfections within DM wounds.

  1. Removal of total and antibiotic resistant bacteria in advanced wastewater treatment by ozonation in combination with different filtering techniques.

    Science.gov (United States)

    Lüddeke, Frauke; Heß, Stefanie; Gallert, Claudia; Winter, Josef; Güde, Hans; Löffler, Herbert

    2015-02-01

    Elimination of bacteria by ozonation in combination with charcoal or slow sand filtration for advanced sewage treatment to improve the quality of treated sewage and to reduce the potential risk for human health of receiving surface waters was investigated in pilot scale at the sewage treatment plant Eriskirch, Baden-Wuerttemberg/Germany. To determine the elimination of sewage bacteria, inflowing and leaving wastewater of different treatment processes was analysed in a culture-based approach for its content of Escherichia coli, enterococci and staphylococci and their resistance against selected antibiotics over a period of 17 month. For enterococci, single species and their antibiotic resistances were identified. In comparison to the established flocculation filtration at Eriskirch, ozonation plus charcoal or sand filtration (pilot-scale) reduced the concentrations of total and antibiotic resistant E. coli, enterococci and staphylococci. However, antibiotic resistant E. coli and staphylococci apparently survived ozone treatment better than antibiotic sensitive strains. Neither vancomycin resistant enterococci nor methicillin resistant Staphylococcus aureus (MRSA) were detected. The decreased percentage of antibiotic resistant enterococci after ozonation may be explained by a different ozone sensitivity of species: Enterococcus faecium and Enterococcus faecalis, which determined the resistance-level, seemed to be more sensitive for ozone than other Enterococcus-species. Overall, ozonation followed by charcoal or sand filtration led to 0.8-1.1 log-units less total and antibiotic resistant E. coli, enterococci and staphylococci, as compared to the respective concentrations in treated sewage by only flocculation filtration. Thus, advanced wastewater treatment by ozonation plus charcoal or sand filtration after common sewage treatment is an effective tool for further elimination of microorganisms from sewage before discharge in surface waters.

  2. Variabilidades fenotípica e genotípica de estirpes de Staphylococcus aureus isoladas em casos de mastite subclínica bovina Phenotypic and genotypic variabilities of Staphylococcus aureus strains isolated from bovine subclinical mastitis

    Directory of Open Access Journals (Sweden)

    Luciano Menezes Ferreira

    2006-08-01

    Full Text Available Foram submetidas a PCR-Ribotipagem e aos testes de sensibilidade in vitro frente a 12 antimicrobianos 77 estirpes de Staphylococcus aureus isoladas em amostras de leite procedentes de 40 vacas da raça holandesa que apresentaram mastite subclínica, em uma propriedade rural localizada no Estado de São Paulo, Brasil. Os resultados obtidos revelaram quatro diferentes padrões de resistência a antimicrobianos, sendo observada a predominância de resistência à lincomicina entre 19 (24,7% estirpes de S.aureus. As 58 (75,3% estirpes restantes foram sensíveis aos 12 antimicrobianos testados. A PCR-ribotipagem revelou a ocorrência de nove padrões genotípicos distintos, além de apresentar uma capacidade discriminatória maior (D = 0,82 que a obtida nos antibiogramas (D = 0,42. Entre as 19 estirpes resistentes aos antimicrobianos, 14 (73,7% foram agrupadas em três padrões de ribotipagem e, destas, 13 (92,9% apresentaram resistência à eritromicina e à lincomicina, isoladamente ou em associação. O grande número de ribotipos e de padrões de resistência a antimicrobianos observados nesta propriedade demonstrou que há grande heterogeneidade genética em populações naturais de S. aureus, fato este que deve ser levado em consideração em programas de controle da mastite bovina.Seventy-seven S. aureus strains, isolated in milk samples obtained from 40 Holstein cows suffering from subclinical mastitis in a dairy herd in the state of São Paulo - Brazil, were undergone to PCR-ribotyping and in vitro susceptibility testing to 12 antimicrobial drugs. PCR-ribotyping revealed nine different patterns and presented a higher discriminatory power (D = 0.82 in comparison with the in vitro antibiotic susceptibility test (D = 0.42. Moreover,, the results showed four antibiotic resistance patterns, with the resistance to lincomycin being the most predominant and comprising 19 (24.7% S. aureus strains. The other 58 (75.3% isolates were sensitive to all

  3. Staphylococcus epidermidis ΔSortase A strain elicits protective immunity against Staphylococcus aureus infection.

    Science.gov (United States)

    Tan, Chao; Wang, Jun; Hu, Yifang; Wang, Peng; Zou, Lili

    2017-01-01

    Staphylococcus aureus and Staphylococcus epidermidis are two of the most significant opportunistic human pathogens, causing medical implant and nosocomial infections worldwide. These bacteria contain surface proteins that play crucial roles in multiple biological processes. It has become apparent that they have evolved a number of unique mechanisms by which they can immobilise proteins on their surface. Notably, a conserved cell membrane-anchored enzyme, sortase A (SrtA), can catalyse the covalent attachment of precursor bacterial cell wall-attached proteins to peptidoglycan. Considering its indispensable role in anchoring substrates to the cell wall and its effects on virulence, SrtA has attracted great attention. In this study, a 549-bp gene was cloned from a pathogenic S. epidermidis strain, YC-1, which shared high identity with srtA from other Staphylococcus spp. A mutant strain, YC-1ΔsrtA, was then constructed by allelic exchange mutagenesis. The direct survival rate assay suggested that YC-1ΔsrtA had a lower survival capacity in healthy mice blood compare with the wild-type strain, indicating that the deletion of srtA affects the virulence and infectious capacity of S. epidermidis YC-1. YC-1ΔsrtA was then administered via intraperitoneal injection and it provided a relative percent survival value of 72.7 % in mice against S. aureus TC-1 challenge. These findings demonstrate the possbility that YC-1ΔsrtA might be used as a live attenuated vaccine to produce cross-protection against S. aureus.

  4. Minimum inhibitory concentration of ciprofloxacin in combination with hexahydroquinoline derivatives against Staphylococcus aureus

    OpenAIRE

    F Amin Harati; M Amini; Shahverdi AR; Pourmand, MR; Yousefi, M.

    2012-01-01

    Background: Staphylococcus aureus is the most common pathogen responsible for skin and soft tissue infections worldwide. Methicillin-resistant S. aureus is a major cause of both nosocomial and community acquired infections. The emergence of antimicrobial-resistant S. aureus is of global concern. Fluoroquinolone antimicrobials including ciprofloxacin, levofloxacin, and moxifloxacin are used to treat skin and soft tissue infections due to S. aureus. Emergence of ciprofloxacin resistance has inc...

  5. Changes in the Staphylococcus aureus Transcriptome during Early Adaptation to the Lung

    OpenAIRE

    Chaffin, Donald O.; Destry Taylor; Skerrett, Shawn J.; Craig E Rubens

    2012-01-01

    Staphylococcus aureus is a common inhabitant of the human nasopharynx. It is also a cause of life-threatening illness, producing a potent array of virulence factors that enable survival in normally sterile sites. The transformation of S. aureus from commensal to pathogen is poorly understood. We analyzed S. aureus gene expression during adaptation to the lung using a mouse model of S. aureus pneumonia. Bacteria were isolated by bronchoalveolar lavage after residence in vivo for up to 6 hours....

  6. Epidemic Increase in Methicillin-resistant Staphylococcus aureus in Copenhagen

    DEFF Research Database (Denmark)

    Westh, Henrik; Boye, Kit; Bartels, Mette Damkjær

    2006-01-01

    outbreaks and is endemic in 10 nursing homes. Five staff members from nursing homes have been infected with MRSA. MRSA commonly causes skin and soft tissue infections (76%), but serious infections such as septicaemia and pneumonia are also found. CONCLUSION: Treatment of MRSA-infected patients is costly due......INTRODUCTION: We have found an epidemic increase in methicillin-resistant Staphylococcus aureus (MRSA) in Copenhagen. The increase has a complex background and involves hospitals, nursing homes and persons nursed in their own home. MATERIAL AND METHODS: We found 33 MRSA patients in 2003 and 121...... resources for handling the epidemic are not available. Without active intervention, this situation will have serious implications for the health care system....

  7. Quinupristin/dalfopristin in Staphylococcus aureus endophthalmitis: a case report

    Directory of Open Access Journals (Sweden)

    Hernandez-Da Mota Sergio E

    2011-03-01

    Full Text Available Abstract Introduction The intravitreal injection of antibiotics remains the mainstay of therapy for postoperative endophthalmitis. Bacterial resistance, however, is still a pitfall in achieving an adequate response to treatment. Quinupristin/dalfopristin might be a feasible therapeutic option in these cases. Case presentation A 55-year-old Hispanic man had endophthalmitis secondary to Staphylococcus aureus in his right eye and was treated with intravitreal 0.4 mg/0.1 ml quinupristin/dalfopristin injection. Inflammation and pain remission were observed at four days after injection. The final best-corrected visual acuity was 20/40. Conclusion Although vancomycin remains the first-line intravitreal antibiotic therapy against infectious endophthalmitis caused by Gram-positive bacteria, quinupristin/dalfopristin exhibits similar efficacy and is theoretically more active against vancomycin-resistant strains, with no apparent retinal toxicity.

  8. Colonization of Cimex lectularius with methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Barbarin, Alexis M; Hu, Baofeng; Nachamkin, Irving; Levy, Michael Z

    2014-05-01

    A recent paper published by Lowe and Romney in Emerging Infectious Diseases titled, Bed bugs as Vectors for Drug-Resistant Bacteria has sparked a renewed interest in bed bug vector potential. We followed a pyrethroid resistant strain of the human bed bug (Cimex lectularius, L.) fed either human blood or human blood with added methicillin resistant Staphylococcus aureus (MRSA) for 9 days post-feeding. Results indicated that while the bed bug midgut is a hospitable environment for MRSA, the bacteria does not survive longer than 9 days within the midgut. Additionally, MRSA is not amplified within the midgut of the bug as the infection was cleared within 9 days. Due to the weekly feeding behaviours of bed bugs, these results suggest that bed bug transmission of MRSA is highly unlikely.

  9. Strategies for controlling methicillin-resistant Staphylococcus aureus in hospitals.

    Science.gov (United States)

    Boyce, J M

    1995-07-01

    In areas where the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) is very low, aggressive strategies, which appear to have been effective, such as those used in the Netherlands and western Australia, may be feasible. In hospitals where MRSA is epidemic or highly endemic, less rigorous strategies are appropriate. However, which isolation techniques and barrier precautions are optimal is controversial. In addition, there is no consensus regarding the epidemiological importance of environmental contamination. Rapid detection of MRSA, prompt implementation of barrier precautions and prospective surveillance are essential components of a successful control programme. Eradicating nasal carriage of MRSA among patients and personnel can be useful during epidemics, but the cost-effectiveness of using this approach in hospitals where the prevalence of MRSA is low is unknown. Additional studies of this issue need to include surveillance for mupirocin-resistant strains.

  10. Bilateral sudden sensorineural hearing loss in Staphylococcus aureus endocarditis.

    Science.gov (United States)

    Lau, Joanne Wai Ling; Ceranic, Borka; Harris, Robert; Timehin, Elwina

    2015-09-14

    This case highlights the diagnostic challenges in patients presenting with bilateral sudden sensorinueral hearing loss (SNHL). The aetiology of bilateral sudden SNHL may span several medical disciplines. Therefore, clinicians should be mindful of such presentations, and consider aetiologies beyond otological and neurological causes. We present a case of a previously healthy 51-year-old woman who presented with coryzal symptoms and sudden audiovestibular failure. Examination revealed fever, tachycardia, bilateral profound hearing loss and nystagmus. Following investigations, an initial working diagnosis of vasculitis was made. Later, blood cultures revealed methicillin-sensitive Staphylococcus aureus (MSSA) and a transoesophageal echocardiogram confirmed endocarditis. The patient made a good recovery, but the hearing loss was permanent and managed with a cochlear implant.

  11. Ceftobiprole- and ceftaroline-resistant methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Chan, Liana C; Basuino, Li; Diep, Binh; Hamilton, Stephanie; Chatterjee, Som S; Chambers, Henry F

    2015-05-01

    The role of mecA mutations in conferring resistance to ceftobiprole and ceftaroline, cephalosporins with anti-methicillin-resistant Staphylococcus aureus (MRSA) activity, was determined with MRSA strains COL and SF8300. The SF8300 ceftaroline-passaged mutant carried a single mecA mutation, E447K (E-to-K change at position 447), and expressed low-level resistance. This mutation in COL conferred high-level resistance to ceftobiprole but only low-level resistance to ceftaroline. The COL ceftaroline-passaged mutant, which expressed high-level resistance to ceftobiprole and ceftaroline, had mutations in pbp2, pbp4, and gdpP but not mecA.

  12. Evolution of Staphylococcus aureus during human colonization and infection.

    Science.gov (United States)

    Fitzgerald, J Ross

    2014-01-01

    The diversification of bacterial pathogens during infection is central to their capacity to adapt to different anatomical niches, evade the host immune system, and overcome therapeutic challenges. For example, antimicrobial treatment may fail due to the development of resistance during infection, which is often accompanied by transition to a less virulent state during chronic, persistent infection. In this review, the adaptation of the major human pathogen Staphylococcus aureus to its host environment during infection will be discussed, particularly in the context of new sequencing technologies which have opened a gateway towards understanding of the molecular processes underlying those adaptations. We now have the capacity to address previously intractable questions regarding bacterial diversification during infection which will ultimately lead to enhanced understanding of pathogenesis and the nature of epidemics, and will inform the design of effective therapeutic measures.

  13. Reversal of methicillin resistance in Staphylococcus aureus by thioridazine

    DEFF Research Database (Denmark)

    Klitgaard, Janne K; Skov, Marianne N; Kallipolitis, Birgitte H;

    2008-01-01

    Objectives Thioridazine has been shown to reverse oxacillin resistance in methicillin-resistant Staphylococcus aureus (MRSA) in vitro. The aim of this study was to investigate whether thioridazine alone or in combination with oxacillin affects the transcription of the methicillin resistance gene...... mecA and the protein level of the encoded protein PBP2a. Methods Viability of MRSA was determined in liquid media in the presence of oxacillin or thioridazine alone or in combination. Transcription of mecA was analysed by primer extension, and the protein level of PBP2a was analysed by western...... of thioridazine in the presence of a fixed amount of oxacillin. Furthermore, the protein level of PBP2a was reduced when bacteria were treated with the combination of oxacillin and thioridazine. The two drugs also affected the mRNA level of the beta-lactamase gene, blaZ. Conclusions The present study indicates...

  14. Petrifilm rapid S. aureus Count Plate method for rapid enumeration of Staphylococcus aureus in selected foods: collaborative study.

    Science.gov (United States)

    Silbernagel, K M; Lindberg, K G

    2001-01-01

    A rehydratable dry-film plating method for Staphylococcus aureus in foods, the 3M Petrifilm Rapid S. aureus Count Plate method, was compared with AOAC Official Method 975.55 (Staphylococcus aureus in Foods). Nine foods-instant nonfat dried milk, dry seasoned vegetable coating, frozen hash browns, frozen cooked chicken patty, frozen ground raw pork, shredded cheddar cheese, fresh green beans, pasta filled with beef and cheese, and egg custard-were analyzed for S. aureus by 13 collaborating laboratories. For each food tested, the collaborators received 8 blind test samples consisting of a control sample and 3 levels of inoculated test sample, each in duplicate. The mean log counts for the methods were comparable for pasta filled with beef and cheese; frozen hash browns; cooked chicken patty; egg custard; frozen ground raw pork; and instant nonfat dried milk. The repeatability and reproducibility variances of the Petrifilm Rapid S. aureus Count Plate method were similar to those of the standard method.

  15. Phenazine antibiotic inspired discovery of potent bromophenazine antibacterial agents against Staphylococcus aureus and Staphylococcus epidermidis.

    Science.gov (United States)

    Borrero, Nicholas V; Bai, Fang; Perez, Cristian; Duong, Benjamin Q; Rocca, James R; Jin, Shouguang; Huigens, Robert W

    2014-02-14

    Nearly all clinically used antibiotics have been (1) discovered from microorganisms (2) using phenotype screens to identify inhibitors of bacterial growth. The effectiveness of these antibiotics is attributed to their endogenous roles as bacterial warfare agents against competing microorganisms. Unfortunately, every class of clinically used antibiotic has been met with drug resistant bacteria. In fact, the emergence of resistant bacterial infections coupled to the dismal pipeline of new antibacterial agents has resulted in a global health care crisis. There is an urgent need for innovative antibacterial strategies and treatment options to effectively combat drug resistant bacterial pathogens. Here, we describe the implementation of a Pseudomonas competition strategy, using redox-active phenazines, to identify novel antibacterial leads against Staphylococcus aureus and Staphylococcus epidermidis. In this report, we describe the chemical synthesis and evaluation of a diverse 27-membered phenazine library. Using this microbial warfare inspired approach, we have identified several bromophenazines with potent antibacterial activities against S. aureus and S. epidermidis. The most potent bromophenazine analogue from this focused library demonstrated a minimum inhibitory concentration (MIC) of 0.78-1.56 μM, or 0.31-0.62 μg mL(-1), against S. aureus and S. epidermidis and proved to be 32- to 64-fold more potent than the phenazine antibiotic pyocyanin in head-to-head MIC experiments. In addition to the discovery of potent antibacterial agents against S. aureus and S. epidermidis, we also report a detailed structure-activity relationship for this class of bromophenazine small molecules.

  16. Antibiotic resistance profiles among mesophilic aerobic bacteria in Nigerian chicken litter and associated antibiotic resistance genes1.

    Science.gov (United States)

    Olonitola, Olayeni Stephen; Fahrenfeld, Nicole; Pruden, Amy

    2015-05-01

    The effect of global antibiotic use practices in livestock on the emergence of antibiotic resistant pathogens is poorly understood. There is a paucity of data among African nations, which suffer from high rates of antibiotic resistant infections among the human population. Escherichia (29.5%), Staphylococcus (15.8%), and Proteus (15.79%) were the dominant bacterial genera isolated from chicken litter from four different farms in Zaria, Nigeria, all of which contain human pathogenic members. Escherichia isolates were uniformly susceptible to augmentin and cefuroxime, but resistant to sulfamethoxazole (54.5%), ampicillin (22.7%), ciprofloxacin (18.2%), cephalothin (13.6%) and gentamicin (13.6%). Staphylococcus isolates were susceptible to ciprofloxacin, gentamicin, and sulfamethoxazole, but resistant to tetracycline (86.7%), erythromycin (80%), clindamycin (60%), and penicillin (33.3%). Many of the isolates (65.4%) were resistant to multiple antibiotics, with a multiple antibiotic resistance index (MARI) ≥ 0.2. sul1, sul2, and vanA were the most commonly detected antibiotic resistance genes among the isolates. Chicken litter associated with antibiotic use and farming practices in Nigeria could be a public health concern given that the antibiotic resistant patterns among genera containing pathogens indicate the potential for antibiotic treatment failure. However, the MARI values were generally lower than reported for Escherichia coli from intensive poultry operations in industrial nations.

  17. Efficacy of Linezolid and Fosfomycin in Catheter-Related Biofilm Infection Caused by Methicillin-Resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Dong Chai

    2016-01-01

    Full Text Available As long-standing clinical problems, catheter-related infections and other chronic biofilm infections are more difficult to treat due to the high antibiotic resistance of biofilm. Therefore, new treatments are needed for more effective bacteria clearance. In this study, we evaluated the antibacterial activities of several common antibiotics alone and their combinations against biofilm-embedded methicillin-resistant staphylococcus aureus (MRSA infections, both in vitro and in vivo. In brief, fosfomycin, levofloxacin, and rifampin alone or in combination with linezolid were tested in vitro against planktonic and biofilm-embedded MRSA infection in three MRSA stains. The synergistic effects between linezolid and the other three antibiotics were assessed by fractional inhibitory concentration index (FICI and time-kill curves, where the combination of linezolid plus fosfomycin showed the best synergistic effect in all strains. For further evaluation in vivo, we applied the combination of linezolid and fosfomycin in a catheter-related biofilm rat model and found that viable bacteria counts in biofilm were significantly reduced after treatment (P<0.05. In summary, we have shown here that the combination of linezolid and fosfomycin treatment had improved therapeutic effects on biofilm-embedded MRSA infection both in vitro and in vivo, which provided important basis for new clinical therapy development.

  18. Investigation of signal transduction routes within the sensor/transducer protein BlaR1 of Staphylococcus aureus.

    Science.gov (United States)

    Staude, Michael W; Frederick, Thomas E; Natarajan, Sivanandam V; Wilson, Brian D; Tanner, Carol E; Ruggiero, Steven T; Mobashery, Shahriar; Peng, Jeffrey W

    2015-03-03

    The transmembrane antibiotic sensor/signal transducer protein BlaR1 is part of a cohort of proteins that confer β-lactam antibiotic resistance in methicillin-resistant Staphylococcus aureus (MRSA) [Fisher, J. F., Meroueh, S. O., and Mobashery, S. (2005) Chem. Rev. 105, 395-424; Llarrull, L. I., Fisher, J. F., and Mobashery, S. (2009) Antimicrob. Agents Chemother. 53, 4051-4063; Llarrull, L. I., Toth, M., Champion, M. M., and Mobashery, S. (2011) J. Biol. Chem. 286, 38148-38158]. Specifically, BlaR1 regulates the inducible expression of β-lactamases that hydrolytically destroy β-lactam antibiotics. The resistance phenotype starts with β-lactam antibiotic acylation of the BlaR1 extracellular domain (BlaRS). The acylation activates the cytoplasmic protease domain through an obscure signal transduction mechanism. Here, we compare protein dynamics of apo versus antibiotic-acylated BlaRS using nuclear magnetic resonance. Our analyses reveal inter-residue interactions that relay acylation-induced perturbations within the antibiotic-binding site to the transmembrane helix regions near the membrane surface. These are the first insights into the process of signal transduction by BlaR1.

  19. Whole-Genome Sequencing for Routine Pathogen Surveillance in Public Health: a Population Snapshot of Invasive Staphylococcus aureus in Europe

    Directory of Open Access Journals (Sweden)

    David M. Aanensen

    2016-05-01

    Full Text Available The implementation of routine whole-genome sequencing (WGS promises to transform our ability to monitor the emergence and spread of bacterial pathogens. Here we combined WGS data from 308 invasive Staphylococcus aureus isolates corresponding to a pan-European population snapshot, with epidemiological and resistance data. Geospatial visualization of the data is made possible by a generic software tool designed for public health purposes that is available at the project URL (http://www.microreact.org/project/EkUvg9uY?tt=rc. Our analysis demonstrates that high-risk clones can be identified on the basis of population level properties such as clonal relatedness, abundance, and spatial structuring and by inferring virulence and resistance properties on the basis of gene content. We also show that in silico predictions of antibiotic resistance profiles are at least as reliable as phenotypic testing. We argue that this work provides a comprehensive road map illustrating the three vital components for future molecular epidemiological surveillance: (i large-scale structured surveys, (ii WGS, and (iii community-oriented database infrastructure and analysis tools.

  20. Nordihydroguaiaretic acid enhances the activities of aminoglycosides against methicillin- sensitive and resistant Staphylococcus aureus in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Edward eCunningham-Oakes

    2015-10-01

    Full Text Available Infections caused by methicillin-sensitive (MSSA and methicillin-resistant Staphylococcus aureus (MRSA are prevalent. MRSA infections are difficult to treat and there are no new classes of antibiotics produced to the market to treat infections caused by the resistant bacteria. Therefore, using antibiotic enhancers to rescue existing classes of antibiotics is an attractive strategy. Nordihydroguaiaretic acid (NDGA is an antioxidant compound