Sassi, Mohamed; Sharma, Deepak; Brinsmade, Shaun ,; Felden, Brice; Augagneur, Yoann
We report here the draft genome sequence of Staphylococcus aureus subsp. aureus strain UAMS-1. UAMS-1 is a virulent oxacillin-susceptible clinical isolate. Its genome is composed of 2,763,963 bp and will be useful for further gene expression analysis using RNA sequencing (RNA-seq) technology. S taphylococcus aureus is an opportunistic human bacterial pathogen responsible for nosocomial and community-associated infections. S. aureus subsp. aureus strain UAMS-1 was originally isolated from the ...
Grzegorczyk, Agnieszka; Malm, Anna
The paper presents results on the relatedness of Staphylococcus aureus strains colonizing the upper respiratory tract isolated from healthy persistent carriers. Genotyping was carried out using two methods--multiple-locus variable-number tandem-repeat fingerprinting (MLVF) and pulsed-field gel electrophoresis (PFGE). By comparison of the results obtained by both methods, good correlations between MLVF and PFGE genotyping of strains isolated from the asymptomatic carriers were observed. Further studies are needed to evaluate methods useful for genotyping of S. aureus strains circulating in the community. PMID:24488811
Baumgartner, Andreas; Niederhauser, Isabel; Johler, Sophia
Staphylococcal food poisoning represents the most prevalent foodborne intoxication worldwide. Oral intake of staphylococcal enterotoxins from food can result in emesis and diarrhea and can be fatal in children and the elderly. Few data have been available on the characteristics and sources of Staphylococcus aureus strains isolated from ready-to-eat (RTE) foods. In this study, we used a DNA microarray to determine virulence and antimicrobial resistance gene profiles of S. aureus from RTE foods. A total of 267 S. aureus strains isolated from 244 RTE foods were investigated. The isolates originated from precooked foods (41% of isolates), meat and fish products (17%), cheese (13%), delicatessen salads (8%), sandwiches and canapés (8%), confectionery and bakery products (6%), and various other RTE foods (7%). Eleven samples (5%), of which 9 were raw milk cheeses, contained > 10(5) CFU/g, which is considered a health risk. Four S. aureus strains were associated with intoxications; three cases were linked to consumption of cheese and one case was linked to consumption of potato salad. DNA microarray results revealed that one-third of the tested strains had at least one major enterotoxin gene (sea through see). We also detected the toxic shock syndrome gene (18% of isolates) and various genes conferring antimicrobial resistance, including genes involved in resistance to beta-lactams (blaZ, 72% of isolates), methicillin (mecA, 1% of isolates), and vancomycin (vanB, 1% of isolates). S. aureus strains were most frequently assigned to clonal complex (CC) 30 (17% of isolates), CC8 (12%), CC15 (11%), and CC45 (10%), which are commonly detected in humans colonized or infected with S. aureus. Although a large proportion of the tested food items contained milk, we did not detect CC705, the most prevalent clonal complex among S. aureus isolates from bovine mastitis milk. Our results suggest that S. aureus isolates from RTE foods do not commonly originate from animals but more
Full Text Available Strains of S. aureus were isolated from individual milk samples of 500 lacting cows from different areas in Slovakia (PH 1 - Košice region, 300 samples; PH 2 - Žilina region, 200 samples. The statistical significance between both dairy farms included in the experiment in the presence of genus Staphylococcus isolated on Baird-Parker agar from milk samples was p (*** . Totally, 122 milk samples were positive for the presence of Staphylococcus aureus (83 Košice regions, 52 Žilina regions. All 122 isolates of S. aureus were sensitive for the methicilin as detected by interpretative criteria developed by NCCLS (2002. For 122 S. aureus isolates, we compared antibiotic susceptibility results determined by the standardized agar diffusion assay with the PCR assay for the detection of antibiotic resistance mecA gene. For all isolates, we found a correlation between the results of the PCR and those of classical resistance testing. The obtained results were confirmed by PCR analysis, according to which, any of our tested isolate of S. aureus from all 122 individual milk samples from both experimental dairy farms were not positive for the presence of mecA gene coding the methicilin resistance. doi:10.5219/21
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.
Lahtinen, Sampo J; Jalonen, Lotta; Ouwehand, Arthur C; Salminen, Seppo J
Cell-free, pH-controlled supernatants of thirty-eight Bifidobacterium strains isolated from healthy elderly subjects were subjected to antimicrobial activity assay. Bioluminescent indicator strains Staphylococcus aureus RN4220, Escherichia coli K-12, and Salmonella enterica serovar Typhimurium ATCC 14028 were used as targets of antimicrobial activity. The effect of nutrient depletion on the inhibition was eliminated with spent-culture controls. Three out of thirty-eight Bifidobacterium strains were capable of inhibiting the growth of S. aureus. The inhibition was equal to 23.2+/-19.1% to 50.4+/-26.7% of the inhibition caused by 50 IU/ml nisin. Reuterin-producing positive strain Lactobacillus reuteri SD2112 was capable of 86.0+/-24.6% inhibition, but Bifidobacterium lactis Bb-12, a known probiotic strain, showed no inhibition. None of the strains was capable of inhibiting the growth of E. coli or S. enterica. The observed inhibition by bifidobacteria was related to hydrogen peroxide formation and possible production of heat-stable proteinaceous compounds. The results suggest that production of antimicrobial substances other than organic acids is not common among Bifidobacterium strains typical of elderly subjects. However, specific strains were identified which showed considerable inhibitory activity against S. aureus. PMID:17462772
Juuti, Katri; Ibrahem, Salha; Virolainen-Julkunen, Anni; Vuopio-Varkila, Jaana; Kuusela, Pentti
pls, a gene found in type I staphylococcal cassette chromosome mec (SCCmec) regions of methicillin-resistant Staphylococcus aureus strains, was present in 12 of the 15 human clinical Staphylococcus sciuri isolates studied. Pls was expressed in the S. sciuri isolates, although at a lower level than in S. aureus. Other parts of SCCmec could also be found in the S. sciuri genome.
Full Text Available Background: Staphylococcus aureus is a major nosocomial pathogen world wide. Mupirocin plays a crucial role in strategies designed to control outbreaks of S. aureus. .Objectives: The aim of this study was to determine the frequency of mupirocin resistance in S. aureus strains isolated from nasal carriers among the hospitalized patients at Kermanshah Hospital, Iran..Patients and Methods: A total of 174 S. aureus isolates (sensitive and resistant to methicillin were collected from the nasal anterior nares of hospitalized patients. All isolates were tested for mupirocin susceptibility by a disc diffusion method. The minimum inhibitory concentration (MIC was determined by an E-test and they were also analyzed by a PCR for the presence of ileS-1 and ileS-2 genes..Results: Utilizing the disc diffusion agar method, E-test and PCR, all of the S. aureus strains tested were susceptible to mupirocin. In this study, the range of mupirocin MICs was determined to be between 0.064 and 4 μg/ml. There was a significant association between MIC observed and multi-drug resistant (MDR carriage (P value 0.04, and resistance to oxacillin (P value 0.004..Conclusions: This is a report of an initial survey of mupirocin resistance in S. aureus, in Kermanshah where the use of mupirocin is still limited. Perhaps the sensitivity of all isolates to mupirocin in this study is due to the less common usage of this antibiotic, especially in the form of nasal and site sample collections.
Sotto, Albert; Lina, Gérard; Richard, Jean-Louis; Combescure, Christophe; Bourg, Gisèle; Vidal, Laure; Jourdan, Nathalie; Etienne, Jérôme; Lavigne, Jean-Philippe
OBJECTIVE—The purpose of this study was to assess the virulence potential of Staphylococcus aureus strains isolated from diabetic foot ulcers and to discriminate noninfected from infected ulcers. RESEARCH DESIGN AND METHODS—Diabetic patients hospitalized in a diabetic foot department with a foot ulcer were prospectively enrolled if they had been free of antibiotic treatment over the previous 6 months. At admission, ulcers were classified as infected or noninfected on the basis of clinical exa...
Silva, Danielle Mendes; da Silva, Mônica Pacheco; Vidigal, Pedro M Pereira; Barcelos, Rafael Mazioli; Klein, Raphael Contelli; Aguilar, Ananda Pereira; Fabres-Klein, Mary Hellen; Oliveira, Guilherme; Ribon, Andréa Oliveira Barros
Here, we present the draft genome sequences of four Staphylococcus aureus strains isolated from mastitic milk collected from animals with subclinical manifestations. Three of them were typed as sequence type 126 (ST126), a genotype with no genome sequence available. ST126 is found in several herds of southern Brazil and is described as a bovine pathogen strongly associated with milk around the world. PMID:26893417
Murali, Thokur Sreepathy; Paul, Bobby; Parikh, Hersh; Singh, Rana Pratap; Kavitha, Shettigar; Bhat, Manoj K; Satyamoorthy, Kapaettu
Staphylococcus aureus is a major pathogen associated with diabetic foot ulcer infections. To gain insight into their pathogenicity and virulence potential, we report draft genome sequences of four strains of Staphylococcus aureus, isolated from diabetic foot ulcers, showing profiles with various degrees of resistance to common antibiotics.
Kant, Ravi; Taponen, Suvi; Koort, Joanna; Paulin, Lars; Åvall-Jääskeläinen, Silja; Palva, Airi
Staphylococcus aureus is a major causative agent of mastitis in dairy cows. The pathogenicity of S. aureus may vary; it is able to cause severe clinical mastitis, but most often it is associated with chronic subclinical mastitis. Here, we present the genome assemblies of four S. aureus strains from bovine mastitis.
Kant, Ravi; Taponen, Suvi; Koort, Joanna; Paulin, Lars; Åvall-Jääskeläinen, Silja; Palva, Airi
Staphylococcus aureus is a major causative agent of mastitis in dairy cows. The pathogenicity of S. aureus may vary; it is able to cause severe clinical mastitis, but most often it is associated with chronic subclinical mastitis. Here, we present the genome assemblies of four S. aureus strains from bovine mastitis. PMID:25908141
Wladyka, Benedykt; Wielebska, Katarzyna; Wloka, Marcin; Bochenska, Oliwia; Dubin, Grzegorz; Dubin, Adam; Mak, Pawel
Staphylococcus aureus strain CH-91, isolated from a broiler chicken with atopic dermatitis, has a highly proteolytic phenotype that is correlated with the disease. We describe the isolation and biochemical and molecular characterization of the AI-type lantibiotic BacCH91 from S. aureus CH-91 culture medium. The bacteriocin was purified using a three-stage procedure comprising precipitation with ammonium sulfate, extraction with organic solvents, and reversed-phase HPLC. The BacCH91 peptide is...
Djahmi, N; Messad, N; Nedjai, S; Moussaoui, A; Mazouz, D; Richard, J-L; Sotto, A; Lavigne, J-P
Staphylococcus aureus is the most common pathogen cultured from diabetic foot infection (DFI). The consequence of its spread to soft tissue and bony structures is a major causal factor for lower-limb amputation. The objective of the study was to explore ecological data and epidemiological characteristics of S. aureus strains isolated from DFI in an Algerian hospital setting. Patients were included if they were admitted for DFI in the Department of Diabetology at the Annaba University Hospital from April 2011 to March 2012. Ulcers were classified according to the Infectious Diseases Society of America/International Working Group on the Diabetic Foot classification system. All S. aureus isolates were analysed. Using oligonucleotide arrays, S. aureus resistance and virulence genes were determined and each isolate was affiliated to a clonal complex. Among the 128 patients, 277 strains were isolated from 183 samples (1.51 isolate per sample). Aerobic Gram-negative bacilli were the most common isolated organisms (54.9% of all isolates). The study of ecological data highlighted the extremely high rate of multidrug-resistant organisms (MDROs) (58.5% of all isolates). The situation was especially striking for S. aureus [(85.9% were methicillin-resistant S. aureus (MRSA)], Klebsiella pneumonia (83.8%) and Escherichia coli (60%). Among the S. aureus isolates, 82.2% of MRSA belonged to ST239, one of the most worldwide disseminated clones. Ten strains (13.7%) belonged to the European clone PVL+ ST80. ermA, aacA-aphD, aphA, tetM, fosB, sek, seq, lukDE, fnbB, cap8 and agr group 1 genes were significantly associated with MRSA strains (p <0.01). The study shows for the first time the alarming prevalence of MDROs in DFI in Algeria. PMID:23521557
Lv, GuoPing; Xu, BaoHong; Wei, PeiNan; Song, Jie; Zhang, HongYing; Zhao, Chuan; Qin, LiYun; Zhao, BaoHua
Staphylococcus aureus is an opportunistic pathogen commonly identified from food poisoning-associated foodstuffs. From 1996 to the present, S. aureus isolates have been found to exhibit increasing resistance to antimicrobial drugs. The aim of this study was to assess the molecular epidemiology properties of various S. aureus isolates through molecular typing and to investigate their characterization based on their production of enterotoxins and hemolysins and their resistance to antibiotics. A total of 78 coagulase-positive staphylococcal strains isolated from food or clinical samples were analyzed. Eight VNTR loci were used to genotype the 78 isolates, and this analysis resulted in 39 different multilocus variable number tandem repeat analysis (MLVA) profiles. The isolates recovered from a single outbreak exhibited the same MLVA profile. According to CLSI, 97.4% of the isolates were resistant to penicillin, whereas only 3.8% were methicillin-resistant Staphylococcus aureus strains. Through multiplex PCR, 87.2% of the isolates were shown to be enterotoxigenic (SEs), and the most common genes present were sea, sem, seg, seu, and sek. In conclusion, this study demonstrates the prevalence of staphylococcal enterotoxins, the contents of virulent factors, and the characteristics of β-lactam antibiotic resistance in 78 S. aureus isolates. These findings emphasize the need to prevent the presence of S. aureus strains and SE production in foods. Our results also demonstrate that MLVA is a useful and powerful method for epidemiological studies of S. aureus. In contrast to multilocus sequence typing, the MLVA method is a simpler and more rapid method for epidemiological typing with a higher discriminatory power. PMID:24582576
Schlenker, Gerd; Szabo, Istvan; Roesler, Uwe
Sensitivity to commercial teat dips (nonoxinol-9 iodine complex and chlorhexidine digluconate) of 56 Staphylococcus (S.) aureus strains isolated from quarter milk samples of various German dairy herds treated with different teat dipping schemes was investigated in this study. The minimum inhibitory concentration was determined using a broth macrodilution method according to the German Veterinary Association guidelines. The main objective of the current study was to induce in vitro resistance induction of S. aureus to chemical disinfectants. Ten different strains were repeatedly passed ten times in growth media with sub-lethal concentrations of disinfectants. Nine strains showed a significant reduction in susceptibility to the nonoxinol-9 iodine complex but only one strain developed resistance to chlorhexidine digluconate. Stability of the acquired resistance was observed in all S. aureus strains adapted to the nonoxinol-9 iodine complex and chlorhexidine digluconate. In contrast, simultaneous resistance to different antibiotics was not observed in any of the ten investigated S. aureus strains. However, the isolates exhibited a high degree of resistance to penicillin G. Based on these results, resistance of S. aureus to chemical disinfectants may be more likely to develop if the chemicals are used at concentrations lower than that required for an optimal biocidal effect. PMID:22705737
D'amico, Dennis J; Donnelly, Catherine W
Staphylococcus aureus is an important agent of bacterial mastitis in milking animals and of foodborne intoxication in humans. The purpose of this study was to examine the genetic and phenotypic diversity, enterotoxigenicity, and antimicrobial resistance of S. aureus strains isolated from raw milk used for the production of artisan cheese in Vermont. Cross-tabulations revealed that the 16 ribotypes identified among the 90 milk isolates examined were typically associated with a specific animal species and that more than half of these ribotypes were unique to individual farms. In general, specific EcoRI ribotypes were commonly associated with specific phenotypical characteristics, including staphylococcal enterotoxin production or the lack thereof. Limited antimicrobial resistance was observed among the isolates, with resistance to ampicillin (12.51%) or penicillin (17.04%) most common. Two isolates of the same ribotype obtained from the same farm were resistant to oxacillin with 2% NaCl. More than half (52.22%) of isolates produced toxin, and 31 of the 32 isolates solely produced staphylococcal enterotoxin type C. Although these data demonstrate that S. aureus strains found in raw milk intended for artisan cheese manufacture are capable of enterotoxin production, staphylococcal enterotoxin C is not typically linked to foodborne illness. Because S. aureus is a common contaminant of cheese, an understanding of the ecology of this pathogen and of the antimicrobial susceptibility and toxigenicity of various strains will ultimately contribute to the development of control practices needed to enhance the safety of artisan and farmstead cheese production. PMID:21819666
Aarestrup, Frank Møller; Wegener, Henrik Caspar; Rosdahl, V.T.
Fiftytwo strains of S. aureus isolated from cases of bovine subclinical mastitis in 52 different dairy herds in Denmark, in the peri ods 1952 to 1956 and 1992, were compared with regard to their phage- and EcoRI ribotypes. Furthermore, susceptibility to penicillin and production of fibrinolysin...
Melchior, M.B.; van Osch, M.H.J.; Graat, R.M.; van Duijkeren, E.; Mevius, D.J.; Nielen, M.; Gaastra, W.; Fink-Gremmels, J.
The increasing evidence for a role of biofilm formation in bovine mastitis caused by Staphylococcus aureus led to further investigations on biofilm formation by S. aureus isolates from mastitis in two growth media (TSBg and bovine milk serum). The ability of 99 S. aureus strains that were recently i
Melchior, M.B.; Osch, M.H.J.; Graat, R.; Duijkeren, van E.; Mevius, D.J.; Nielen, M.; Gaastra, W.; Fink, J.
The increasing evidence for a role of biofilm formation in bovine mastitis caused by Staphylococcus aureus led to further investigations on biofilm formation by S. aureus isolates from mastitis in two growth media (TSBg and bovine milk serum). The ability of 99 S. aureus strains that were recently i
Strommenger, B; Braulke, C; Pasemann, B; Schmidt, C; Witte, W
The continuous spread of community-acquired methicillin-resistant Staphylococcus aureus (caMRSA) and the introduction of these highly virulent isolates into hospitals represent increasing threats. The timely recognition of caMRSA strains is crucial for infection control purposes. Thus, we developed a PCR-based assay for the easy and rapid determination of those caMRSA clones that currently are the most prevalent in Germany and Central Europe. This assay was able to correctly identify the majority of the isolates as caMRSA of sequence type 80 (ST80), clonal complex 1 (USA400), and ST8 (USA300). In combination with spa typing-BURP (based upon repeat pattern) analysis and resistance typing, it provides a means for the extensive characterization of suspicious isolates. Thus, this assay represents a reliable tool for monitoring the emergence and spread of different caMRSA clones. The resulting information, in combination with careful interpretation of the epidemiological records, might help to prevent the further spread of those highly virulent caMRSA clones. PMID:18032620
Karima G. Abdel Hameed
Full Text Available Aim: The aim was to investigate cheese samples for the prevalence of Staphylococcus aureus, evaluate multiplex polymerase chain reaction (PCR methods for S. aureus identification, as well as to determine the antibacterial activity of silver nanoparticles against such strains. Materials and Methods: Total of 100 random locally manufactured cheese samples were collected from Qena dairy markets, Egypt, and examined conventionally for the prevalence of S. aureus then, confirmation of these isolates were done using multiplex PCR. The antibacterial activity of silver nanoparticles against such isolates was also checked. Results: Lower prevalence of S. aureus in Damietta cheese (54% than in Kareish cheese (62% was recorded. As well lower frequency distribution for both S. aureus (36% and CNS (8% was also reported for Damietta cheese. Using of multiplex PCR method for S. aureus identification have been confirmed all 58 S. aureus stains that were identified conventionally by detection of two PCR products on agarose gel: The 791 bp and the 638 bp. The correlation coefficient between conventional and multiplex PCR method was 0.91 and was significant at p≤0.001. Regarding antibacterial activity of silver nanoparticles using disk diffusion method on Baird Parker agar it was found that inhibition zone of silver nanoparticles against S. aureus, was 19.2±0.91 mm and it was higher than that produced by gentamicin (400 units/ml 15.2±0.89 mm. Conclusions: The present study illustrated the higher prevalence of S. aureus in cheese samples that may constitute a public health hazard to consumers. According to the results, it can be concluded that silver nanoparticles can be used as an effective antibacterial against S. aureus. Thereby, there is a need for an appropriate study for using silver nanoparticles in cleaning and disinfection of equipment and in food packaging.
Růzicková, Vladislava; Karpísková, Renata; Pantůcek, Roman; Pospísilová, Markéta; Cerníková, Pavla; Doskar, Jirí
Twenty-eight enterotoxin H-positive Staphylococcus aureus strains isolated from food samples collected in eleven districts of the Czech Republic between 2000 and 2005 were genotypically characterized by pulsed-field gel electrophoresis (PFGE) profiling, spa gene polymorphism analysis, enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR) fingerprinting and prophage carriage detection. These strains accounted for about 21% of the food-derived, staphylococcal enterotoxin (SE)-positive isolates. One strain, detected in feta cheese, was implicated in a case of enterotoxinosis. Sixteen of the twenty-eight isolates carried the seh gene alone. The remaining twelve strains harbored the seh gene in combination with other enterotoxin genes, most often the seg and sei genes, followed by the sea, seb, sec and sed genes. Comparison of various genomic profiles resulted in the determination of twenty genotypes designated G-1 to G-20. Two new, to date not defined, spa types (t2000 and t2002) were identified in one strain isolated from raw meat and two strains obtained from prepacked pizza. Evidence has been given that the seh-positive S. aureus isolates from foodstuffs did not originate from a single source or a common ancestor. PMID:18054105
Lee, John Hwa
From May 2001 to April 2003, various types of specimens from cattle, pigs, and chickens were collected and examined for the presence of methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA). S. aureus was isolated and positively identified by using Gram staining, colony morphology, tests for coagulase and urease activities, and an API Staph Ident system. Among 1,913 specimens collected from the animals, 421 contained S. aureus; of these, 28 contained S. aureus resistant to concentrations of oxacillin higher than 2 micro g/ml. Isolates from 15 of the 28 specimens were positive by PCR for the mecA gene. Of the 15 mecA-positive MRSA isolates, 12 were from dairy cows and 3 were from chickens. Antimicrobial susceptibility tests of mecA-positive MRSA strains were performed by the disk diffusion method. All isolates were resistant to members of the penicillin family, such as ampicillin, oxacillin, and penicillin. All isolates were also susceptible to amikacin, vancomycin, and trimethoprim-sulfamethoxazole. To determine molecular epidemiological relatedness of these 15 animal MRSA isolates to isolates from humans, random amplified polymorphic DNA (RAPD) patterns were generated by arbitrarily primed PCR. The RAPD patterns of six of the isolates from animals were identical to the patterns of certain isolates from humans. The antibiotypes of the six animal isolates revealed types similar to those of the human isolates. These data suggested that the genomes of the six animal MRSA isolates were very closely related to those of some human MRSA isolates and were a possible source of human infections caused by consuming contaminated food products made from these animals. PMID:14602604
Mashouf, Rasoul Y.; Seyed M. Hosseini; Arabestani, Mohammad R.
Objectives: The aims of our study were to evaluate the prevalence of Staphylococcus aureus (S. aureus) strains in food samples of animal origin, examine their antibacterial susceptibility pattern, and to detect staphylococcal enterotoxin (SEs) genes and the mecA gene in isolated S. aureus strains using the polymerase chain reaction (PCR). Methods: A total of 1050 food samples including 671 raw milk and dairy products and 379 raw meats were collected between September 2013 and June 2014 in Ham...
Ghaleb Adwan; Mohammad Mhanna
Objective:This study has been done to evaluate the interaction between water extracts of Psidium guajava, Rosmarinus officinalis,Salvia fruticosa,Majorana syriaca,Ocimum basilucum,Syzygium aromaticum,Laurus nobilis,and Rosa damascena alone and then synergy testing of these extracts with known antimicrobial agents including oxytetracycline HCl,gentamicin sulfate,penicillin G,cephalexin and enrofloxacin.This study was conducted against five S.aureus isolates;one is Methicillin -resistant Staphylococcus aureus (MRSA)and 4 Methicillin -sensitive Staphylococcus aureus (MSSA).Methods:Evaluation of the interaction between plant extracts and different antimicrobial agents has been done using well -diffusion and microdilution methods. Results:The results of the conducted experiments using well -diffusion method demonstrate that these plants showed in vitro interactions between antimicrobial agents and plant extracts were additive,while using microdi-lution method showed synergistic effects with significant reduction in the MICs of the test antibiotics against these strains of S.aureus.This change in MIC was noticed in all plant extracts against test antibiotics inclu-ding these plants showed weak antibacterial activity by well diffusion method.Synergism effect was occurred in both sensitive and resistant strains but the magnitude of minimum fold reduction of inhibitory concentration in resistant strains especially MRSA strain was higher than the sensitive strains.Coclusion:This study probably suggests the possibility of concurrent use of these antimicrobial drugs and plant extracts in combination in trea-ting infections caused by S.aureus strains or at least the concomitant administration may not impair the antimi-crobial activity of these antibiotics.
Behiry, Ayman El; Schlenker, Gerd; Szabo, Istvan; Roesler, Uwe
Sensitivity to commercial teat dips (nonoxinol-9 iodine complex and chlorhexidine digluconate) of 56 Staphylococcus (S.) aureus strains isolated from quarter milk samples of various German dairy herds treated with different teat dipping schemes was investigated in this study. The minimum inhibitory concentration was determined using a broth macrodilution method according to the German Veterinary Association guidelines. The main objective of the current study was to induce in vitro resistance ...
Aarestrup, Frank Møller; Wegener, Henrik Caspar; Rosdahl, V.T.
Fiftytwo strains of S. aureus isolated from cases of bovine subclinical mastitis in 52 different dairy herds in Denmark, in the peri ods 1952 to 1956 and 1992, were compared with regard to their phage- and EcoRI ribotypes. Furthermore, susceptibility to penicillin and production of fibrinolysin...... were used as additional phenotypic markers. Fortynine strains (94%) could be separated into 12 phage types. Ribotyping assigned the 52 strains to 21 different types. Both methods showed that 57% of the 1950's strains and between 38-45% of the 1992 strains belonged to 3 dominating types. The remaining...... differences. Penicillin resistance only occurred in a single genotype from the 1950's compared to 6 different genotypes among the 1992 strains....
Chongtrakool, Piriyaporn; Ito, Teruyo; Ma, Xiao Xue; Kondo, Yoko; Trakulsomboon, Suwanna; Tiensasitorn, Chuntima; Jamklang, Mantana; Chavalit, Tavinun; Song, Jae-Hoon; Hiramatsu, Keiichi
A description of staphylococcal cassette chromosome mec (SCCmec) elements carried by 615 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in 11 Asian countries is reported, and a novel nomenclatural system based on their structures is proposed. The 615 strains were classified as type 3A (370 strains), type 2A (207 strains), type 2B (32 strains), type 1B (1 strain), and nontypeable (5 strains). The previously reported type III SCCmec (DDBJ/EMBL/GenBank accession no. AB037671...
We report a study of 35 methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates collected between February and May 1998 from 4 different hospitals in Northern and Southern Palestine. The isolates were recovered from infection and carriage sites of patients and hospital environmental samples. The arbitrarily primed PCR (AP-PCR) method with two primers appears to be a useful tool, provides a fast and simple method for genetic analysis of MRSA infections and allows us to differentiate 22 different AP-PCR patterns. The major cluster, however, sharing common AP-PCR as well as a common PFGE pattern, represented 34% of all MRSA isolates. Isolates of these clusters were spread throughout the neonatal and intensive care units of Rafidya hospital during the entire period. In addition, these isolates were distributed in the southern part of Palestine as well. (author)
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common nosocomial pathogens which can cause a broad spectrum of infections. Objectives: The current study aimed to describe the frequency and antibiotic susceptibility patterns of clonal groups of gentamicin-resistant strains of MRSA isolated from a tertiary care hospital in Tehran, Iran. Materials and Methods: A total of 301 S. aureus isolates were collected during January to November 2012. All of the isolates ...
Lee, John Hwa
From May 2001 to April 2003, various types of specimens from cattle, pigs, and chickens were collected and examined for the presence of methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA). S. aureus was isolated and positively identified by using Gram staining, colony morphology, tests for coagulase and urease activities, and an API Staph Ident system. Among 1,913 specimens collected from the animals, 421 contained S. aureus; of these, 28 contained S. aureus resistant to concentrat...
The aim of the present thesis was to conduct an extensive characterization of S. aureus isolated from small ruminant milk and dairy products. S. aureus is considered a major public health concern because of its ability to give disease in human, after consumption of contaminated foods with enterotoxins. This pathogen can aquire resistance against several antibiotics used in human and veterinary practices. Farms and cheese-making plants can serve as a reservoir of S. aureus and are involved in ...
Holtfreter, Silva; Fiona J Radcliff; Grumann, Dorothee; Read, Hannah; Johnson, Sarah; Monecke, Stefan; Ritchie, Stephen; Clow, Fiona; Goerke, Christiane; Bröker, Barbara M.; Fraser, John D.; Wiles, Siouxsie
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-ad...
Yaser; Hamadeh; Tarazi; Ahmed; Mahmoud; Almajali; Mustafa; Mohammad; Kheer; Ababneh; Humam; Shawket; Ahmed; Adnan; Saleem; Jaran
Objective: To determine the prevalence, genetic relatedness, and pattern of antimicrobial susceptibility in methicillin-resistant Staphylococcus aureus(S. aureus)(MRSA) isolated from household dogs, farm dogs, and stray dogs, compared to isolates from their associated personnel.Methods: MRSA was isolated from 250 nasal swabs(150 swabs from dogs and 100 swabs from humans). PCR assays were used to detect the presence of both the nuc and mec A genes,which con firmed the identity of S. aureus isolates and the presence of methicillin resistance,respectively. Disk diffusion was used to determine the antibiotic susceptibility against 15 antimicrobial agents along with an E-test that determined the minimum inhibitory concentration for oxacillin. Pulsed field gel electrophoresis was conducted to determine the genetic relatedness of MRSA isolates from dogs to those from associated and unassociated personnel.Results: The prevalence of S. aureus in dogs and humans was 12.7% and 10.0%respectively, while the prevalence of MRSA isolates in dogs and humans was 5.3% and5.0%, respectively. The prevalence of MRSA isolates in household dogs, farm dogs, and stray dogs was 7.8%, 4.7%, and 0.0%, respectively. MRSA isolates demonstrated a significantly higher rate of multi-resistance against three or more antimicrobial agents than methicillin-susceptible S. aureus(MSSA). Trimethoprim-sulphamethoxazole and chloramphenicol were the most effective antibiotics against all MRSA isolates. Pulsed field gel electrophoresis revealed a strong association between dog MRSA isolates and MRSA isolates from strongly associated personnel.Conclusions: MRSA is prevalent in house dogs, as well as in dog rearing centers and among their strongly associated personnel. A strong association was found between the MRSA isolates from dogs and those from humans who are in close contact. In addition,MRSA isolates showed a high rate of multi-resistance compared to MSSA isolates.
Yaser Hamadeh Tarazi; Ahmed Mahmoud Almajali; Mustafa Mohammad Kheer Ababneh; Humam Shawket Ahmed; Adnan Saleem Jaran
Objective:To determine the prevalence, genetic relatedness, and pattern of antimicrobial susceptibility in methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA) isolated from household dogs, farm dogs, and stray dogs, compared to isolates from their associated personnel. Methods: MRSA was isolated from 250 nasal swabs (150 swabs from dogs and 100 swabs from humans). PCR assays were used to detect the presence of both the nuc and mecA genes, which confirmed the identity of S. aureus isolates and the presence of methicillin resistance, respectively. Disk diffusion was used to determine the antibiotic susceptibility against 15 antimicrobial agents along with an E-test that determined the minimum inhibitory concentration for oxacillin. Pulsed field gel electrophoresis was conducted to determine the genetic relatedness of MRSA isolates from dogs to those from associated and unassociated personnel. Results:The prevalence of S. aureus in dogs and humans was 12.7%and 10.0%respectively, while the prevalence of MRSA isolates in dogs and humans was 5.3%and 5.0%, respectively. The prevalence of MRSA isolates in household dogs, farm dogs, and stray dogs was 7.8%, 4.7%, and 0.0%, respectively. MRSA isolates demonstrated a significantly higher rate of multi-resistance against three or more antimicrobial agents than methicillin-susceptible S. aureus (MSSA). Trimethoprim-sulphamethoxazole and chloramphenicol were the most effective antibiotics against all MRSA isolates. Pulsed field gel electrophoresis revealed a strong association between dog MRSA isolates and MRSA isolates from strongly associated personnel. Conclusions:MRSA is prevalent in house dogs, as well as in dog rearing centers and among their strongly associated personnel. A strong association was found between the MRSA isolates from dogs and those from humans who are in close contact. In addition, MRSA isolates showed a high rate of multi-resistance compared to MSSA isolates.
Ben Bacha, Abir; Moubayed, Nadine Ms; Al-Assaf, Alaa
In this study, a new strain, ALA1, was identified as Staphylococcus aureus by biochemical tests, and its 16S ribosomal DNA sequence was isolated from dromedary milk. ALA1 lipase production was optimized in shake flask experiments and measured with varying pH (3-11), temperature (20-55 °C) and substrate concentrations. The maximum lipase production was recorded at pH 8 and 30 °C for up to 30 H of culture period for the S. aureus ALA1 strain. Among the substrates tested, selected carbon sources, xylose, nitrogen source, yeast extract, and olive oil (1%) were suitable for maximizing lipase production. The effects of surfactants were investigated and showed that Tween 20, Tween 80, and Triton X-100 prevented lipase production. Interestingly, isolate ALA1 was able to grow in high concentrations of benzene or toluene (up to 50% (v/v)). Moreover, the lipolytic activity of the S. aureus ALA1 lipase was stimulated by diethyl ether, whereas almost 100% of S. aureus ALA1 lipase activity was retained in 25% acetone, acetonitrile, benzene, 2-propanol, ethanol, methanol, or toluene. Because of its stability in organic solvent, the S. aureus ALA1 lipase was used as a biocatalyst to synthesize high levels of added value molecules. S. aureus ALA1 lipase could be considered as an ideal choice for applications in detergent formulations because of its high stability and compatibility with various surfactants, oxidizing agents, and commercial detergents. PMID:25828848
Full Text Available Background: Methicillin-resistant Staphylococcus aureus (MRSA has emerged recently worldwide in production animals, particularly pigs and veal calves, which act as reservoirs for MRSA strains for human infection. The study determined the prevalence of MRSA and other resistant strains of S. aureus isolated from the anterior nares of pigs and human handlers on pig farms in Trinidad. Methods: Isolation of S. aureus was done by concurrently inoculating Baird-Parker agar (BPA and Chromagar MRSA (CHROM with swab samples and isolates were identified using standard methods. Suspect MRSA isolates from Chromagar and BPA were subjected to confirmatory test using Oxoid PBP2 latex agglutination test. The disc diffusion method was used to determine resistance to antimicrobial agents. Results: The frequency of isolation of MRSA was 2.1% (15 of 723 for pigs but 0.0% (0 of 72 for humans. Generally, for isolates of S. aureus from humans there was a high frequency of resistance compared with those from pigs, which had moderate resistance to the following antimicrobials: penicillin G (54.5%, 51.5%, ampicillin (59.1%, 49.5%, and streptomycin (59.1%, 37.1%, respectively. There was moderate resistance to tetracycline (36.4%, 41.2% and gentamycin (27.2%, 23.7% for human and pig S. aureus isolates, respectively, and low resistance to sulfamethoxazole-trimethoprim (4.5%, 6.2% and norfloxacin (9.1%, 12.4%, respectively. The frequency of resistance to oxacillin by the disc method was 36.4 and 34.0% from S. aureus isolates from humans and pigs, respectively. Out of a total of 78 isolates of S. aureus from both human and pig sources that were resistant to oxacillin by the disc diffusion method, only 15 (19.2% were confirmed as MRSA by the PBP'2 latex test kit. Conclusions: The detection of MRSA strains in pigs, albeit at a low frequency, coupled with a high frequency of resistance to commonly used antimicrobial agents in pig and humans could have zoonotic and therapeutic
Full Text Available The antimicrobial activity of the synthetic peptide K9CATH was determined by the Resazurin microtitre Method (RMM against a strain of S. aureus isolated from a case of mastitis. To the antibiogram this bacteria strain showed to be resistant to Ampicillin, Erythromycin, Cefeprime, Dicloxaciline and Penicillin (10 U, while the MIC obtained for the K9CATH was 5.66 &mug/mL. Unlike the reference broth method, visual reading for MIC determination with the RMM showed to be easier, rapid, inexpensive and more sensitive for antimicrobial peptide screening, based in a color change from blue (not growth to pink (growth. This is the first time that the resazurin method is used to determine the MIC of the 38 aa´s K9CATH peptide against a mastitic isolate of S. aureus.
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.
Liu, Xiaoli; Liang, Jiansheng; Jiang, Yuanshan; Wang, Bin; Yuan, Hong; Zhang, Lihua; Zhou, Yanfei; Xu, Huiqiong; Zhou, Wang
This study aims to investigate the antimicrobial susceptibility, molecular characteristics and virulence genes of community-acquired methicillin-resistant ITALIC! Staphylococcus aureus(CA-MRSA) isolates with skin and soft tissue infections (SSTIs). Outpatients with SSTIs visiting five medical and health institutions were enrolled from 2011 to 2013. Available ITALIC! S. aureus isolates were characterized by antimicrobial susceptibility testing, and detection of PVL genes. For CA-MRSA isolates, we performed typing of staphylococcal cassette chromosome ITALIC! mec(SCC ITALIC! mec), multi locus sequence typing (MLST) and carriage of 27 virulence genes. A total of 203 ITALIC! S. aureusstrains were isolated from 1400 outpatients with SSTIs, and 21 (10.3%) were CA-MRSA isolates. The positive rate of PVL genes among ITALIC! S. aureus, CA-MRSA and methicillin-susceptible ITALIC! S. aureus(MSSA) isolates were 39.4%, 71.4% and 35.7%, respectively. CA-MRSA strains had greater sensitivity to non-β-lactam antimicrobial agents. All CA-MRSA isolates belonged to SCC ITALIC! mecIV and V, accounting for 47.6% and 52.4%, respectively. ST59 was the most common lineage accounting for 76.2%; ST59-SCC ITALIC! mecIVa-PVL-positive clone was found to be the predominant clone, accounting for 38.1%. All CA-MRSA isolates were found to be positive for one or more virulence genes, 28.6% of isolates carried PVL, ITALIC! seb, ITALIC! sek, ITALIC! seq, ITALIC! hla, ITALIC! hlb, ITALIC! hldand ITALIC! hlg-2. CA-MRSA infections were relatively uncommon in outpatients with SSTIs, but they carried many virulence genes, ST59-SCC ITALIC! mecIV a-PVL-positive clone was the predominant clone in Wuhan, China. PMID:27060098
Rasoul Y. Mashouf
Full Text Available Objectives: The aims of our study were to evaluate the prevalence of Staphylococcus aureus (S. aureus strains in food samples of animal origin, examine their antibacterial susceptibility pattern, and to detect staphylococcal enterotoxin (SEs genes and the mecA gene in isolated S. aureus strains using the polymerase chain reaction (PCR. Methods: A total of 1050 food samples including 671 raw milk and dairy products and 379 raw meats were collected between September 2013 and June 2014 in Hamadan, Iran. Food samples were analyzed for S. aureus identification. The antibiotic susceptibility pattern of all isolates was determined using the disk agar diffusion method followed by detecting mecA resistance gene using PCR. In addition, harboring of SE genes were determined using a multiplex PCR assay targeting nine genes. Results: A total of 98 (9.3% S. aureus strains were isolated from 1050 food samples. Of the 98 isolates examined, the most frequent resistance was observed to erythromycin (30.6%, followed by tetracycline (29.6%, gentamicin (27.6%, clindamycin (26.5%, ciprofloxacin and rifampin (24.5%, trimethoprim-sulfamethoxazole (14.3%, and cefoxitin (5.1%. All cefoxitin resistant isolates were positive for mecA. The prevalence of SEs was 77.6% (n=76. Among the genes that code classic enterotoxins, sea was the most frequent and was carried by 25.5% of isolates, followed by see in 18.4%, sed in 11.2%, sec in 5.1%, and seb in 4.1% of isolates. Among the detected enterotoxins, seg was the predominantly identified enterotoxin gene in isolates with prevalence of 35.7%. The seh gene with prevalence of 1% and sei gene with 3.1% were other detected enterotoxins with low frequencies. Conclusion: The high prevalence of SE genes detected indicates a potential risk for causing animal-originated food poisoning. The increasing prevalence of community-acquired MRSA and its emerging antibiotic resistance in foods is a serious problem for public health.
Wang, Junfeng; Liu, Yanhong; Wan, Daiwei; Fang, Xiangqun; Li, Tianzhi; Guo, Yinghua; Chang, De; Su, Longxiang; Wang, Yajuan; Zhao, Jiao; Liu, Changting
Staphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. S. aureus is the most common species of Staphylococcus to cause staphylococcal infections, which are very common in clinical medicine. Here we report the genome sequence of S. aureus strain LCT-SA112, which was isolated from S. aureus subsp. aureus CGMCC 1.230.
Pellegrino, MS; Frola, ID; Odierno, LM; Bogni, CI
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.
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.
Avaliação da tolerância à vancomicina em 395 cepas hospitalares de Staphylococcus aureus resistentes à oxacilina Evaluation of the tolerance to vancomycin in 395 oxacillin-resistant Staphylococcus aureus strains isolated from Brazilian hospitals
Geraldo A. Oliveira
Full Text Available O objetivo deste estudo foi avaliar a presença de tolerância à vancomicina em cepas de Staphylococcus aureus resistentes à oxacilina (Orsa isoladas de quatro hospitais da cidade de São Paulo. Foram estudadas 395 cepas Orsa isoladas de pacientes hospitalizados entre outubro de 1998 e maio de 2000. A determinação da concentração inibitória mínima (CIM e da concentração bactericida mínima (CBM para vancomicina foi realizada conforme padronizado pelo National Committee for Clinical Laboratory Standards (NCCLS. A tolerância à vancomicina foi definida como a razão CBM/CIM > ou = 32. Do total de cepas estudadas, 10,4% apresentaram CIM de 0,5µg/ml para vancomicina; 41,3%, CIM de 1µg/ml; 42,2%, CIM de 2µg/ml; e 6,1%, CIM de 4µg/ml. Em média, 49,1% dos Orsa apresentaram tolerância à vancomicina. Em conclusão, a tolerância à vancomicina entre as cepas Orsa foi considerada elevada. Conseqüentemente, aumentam as chances de falhas no tratamento com vancomicina, além de aumentar o risco da emergência de Staphylococcus aureus vancomicina-intermediário.The objective of this study was to evaluate the presence of tolerance to vancomycin in oxacillin-resistant Staphylococcus aureus (Orsa strains isolated from four hospitals in the city of São Paulo. From October/1998 to May/2000 we analysed 395 Orsa strains isolated from hospitalized patients. MIC and MBC to vancomycin were determined as standardised by National Committee for Clinical Laboratory Standards (NCCLS. Tolerance was defined as the ratio MBC/MIC > or = 32. The results showed that 10.4% of the Orsa strains presented a MIC of 0.5µg/mL for vancomycin, 41.3% presented a MIC of 1µg/mL, 42.2% a MIC of 2µg/mL and 6.1% a MIC of 4µg/mL. On average, 49,1% of the Orsa presented tolerance to vancomycin. We conclude that the tolerance to vancomycin amongst the Orsa strains was considered high. These high levels of tolerance augment the chances of failure in the treatment with
Sung, Julia M.-L.; Lindsay, Jodi A
We identified naturally occurring Staphylococcus aureus mutants of the restriction modification pathway SauI, including bovine lineage ST151. In a model of vancomycin resistance transfer from Enterococcus faecalis, ST151 isolates are 500 times more susceptible than human S. aureus isolates. The eradication of “hyperrecipient” strains may reduce the evolution of vancomycin-resistant S. aureus.
Balaram Das; Debasis Mandal; Sandeep Kumar Dash; Sourav Chattopadhyay; Satyajit Tripathy; Durga Pada Dolai; Sankar Kumar Dey; Somenath Roy
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. ...
Holtfreter, Silva; Radcliff, Fiona J; Grumann, Dorothee; Read, Hannah; Johnson, Sarah; Monecke, Stefan; Ritchie, Stephen; Clow, Fiona; Goerke, Christiane; Bröker, Barbara M; Fraser, John D; Wiles, Siouxsie
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. PMID:24023720
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.
Le Maréchal Caroline; Jardin Julien; Jan Gwenaël; Even Sergine; Pulido Coralie; Guibert Jean-Michel; Hernandez David; François Patrice; Schrenzel Jacques; Demon Dieter; Meyer Evelyne; Berkova Nadia; Thiéry Richard; Vautor Eric; Le Loir Yves
Abstract Staphylococcus aureus is a major cause of mastitis in ruminants. In ewe mastitis, symptoms range from subclinical to gangrenous mastitis. S. aureus factors or host-factors contributing to the different outcomes are not completely elucidated. In this study, experimental mastitis was induced on primiparous ewes using two S. aureus strains, isolated from gangrenous (strain O11) or subclinical (strain O46) mastitis. Strains induced drastically distinct clinical symptoms when tested in ew...
Comparison of Virulence Gene Identification, Ribosomal Spacer PCR, and Pulsed-Field Gel Electrophoresis for Typing of Staphylococcus aureus Strains Isolated from Cases of Subclinical Bovine Mastitis in the United States.
Adkins, Pamela R F; Middleton, John R; Fox, Lawrence K
Staphylococcus aureus is one of the most important pathogens causing contagious mastitis in dairy cattle worldwide. The objectives of this study were to determine if recently described S. aureus genotype B was present among previously characterized isolates from cases of bovine intramammary infection in the United States and to compare pulsed-field gel electrophoresis (PFGE) to the combination of ribosomal spacer PCR (RS-PCR) and virulence gene identification for typing of S. aureus strains. The hypothesis was that isolates that were previously characterized as contagious would be identified as genotype B and that the results of the two strain-typing methods would be comparable. Isolates were selected from a collection of S. aureus isolates from eight dairy farms. Mammary quarter milk somatic cell count (SCC) and N-acetyl-β-d-gluconaminidase (NAGase) activity data were known and used to evaluate strain pathogenicity. RS-PCR was performed with conventional gel electrophoresis, and PCR was used for toxin gene identification. RS-PCR patterns were associated with a specific virulence gene pattern, as previously reported. Five RS-PCR banding patterns were identified. None of the isolates were characterized as genotype B. No association between RS-PCR types and milk SCC was found; however, NAGase activity was significantly higher in milk from mammary glands infected with RS-PCR banding type 1 (RSP type 1) than in milk from those infected with RSP type 2. The discriminatory power values were 1.0 and 0.46 for PFGE and RS-PCR, respectively. These data suggest that genotype B may have a limited geographic distribution and that PFGE is more discriminatory than RS-PCR performed with conventional gel electrophoresis for typing of S. aureus isolates of bovine origin. PMID:27194685
Cenci-Goga, B T; Karama, M; Rossitto, P V; Morgante, R A; Cullor, J S
Staphylococcus aureus is an important cause of mastitis in cows. The ability of S. aureus strains to produce one or more enterotoxins in milk and dairy products is linked to staphylococcal food poisoning. To determine whether staphylococci causing bovine mastitis could cause human foodborne intoxication, the production of staphylococcal enterotoxins A through D (SEA, SEB, SEC, and SED) by 160 S. aureus isolates was evaluated with the use of a reverse passive latex agglutination enterotoxin kit. All S. aureus strains were isolated over a 9-month period from 2,343 routine submissions of a composite quarter collection of individual mastitic cows at 18 dairy farms in the San Joaquin Valley in California. Prior to enterotoxin detection, isolates were grown by a method that enhances the in vitro synthesis of enterotoxin. Twenty-two of 160 S. aureus isolates produced enterotoxin. Seven produced SEC, 12 produced SED, and 3 produced both SEC and SED. None of the isolates produced SEA or SEB. PMID:14503727
Subhankari Prasad Chakraborty; Santanu Kar Mahapatra; Somenath Roy
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.
Spreading of genes encoding enterotoxins, haemolysins, adhesin and biofilm among methicillin resistant Staphylococcus aureus strains with staphylococcal cassette chromosome mec type IIIA isolated from burn patients.
Motallebi, Mitra; Jabalameli, Fereshteh; Asadollahi, Kheirollah; Taherikalani, Morovat; Emaneini, Mohammad
The emergence of antibiotic-resistant Staphylococcus aureus in particular methicillin-resistant S. aureus (MRSA) is an important concern in burn medical centers either in Iran or worldwide. A total of 128 S. aureus isolates were collected from wound infection of burn patients during June 2013 to June 2014. Multiplex-polymerase chain reaction (MPCR) assay was performed for the characterization of the staphylococcal cassette chromosome mec (SCCmec). Genes encoding virulence factors and biofilm were targeted by PCR. Of 128 S. aureus isolates, 77 (60.1%) isolates were MRSA. Fifty four (70.1%) isolates were identified as SCCmec type IIIA. The most frequently detected toxin genes among MRSA isolates with SCCmec type IIIA were sea (64.1%) and hla (51.8%). The rate of coexistence of sea with hla and sea with hla and hlb was 37% and12.9%, respectively. The sec, eta, tst, pvl, hla and hlb genes were not detected in any of the MRSA isolates. The most prevalent genes encoding biofilm was eno, found in 61.1% of isolates, followed by fib and icaA found in 48.1% and 38.8% of the isolates, respectively. The rate of coexistence of fib + eno + icaA + icaD and fib + eno was 20.3% and 9.2%, respectively. The ebps gene was not detected in any of the isolates. In conclusion, our study indicated that the sea, hla, fib and icaA were most frequent genes encoding virulence factors among MRSA with SCCmec type IIIA isolated from burn wound infection. Moreover, the results of this study shows that the rate of coexistence of genes encoding different virulence factor were high. PMID:27238459
Nakamura, T.(International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo, Tokyo, Japan); Yamazaki, N; Taniguchi, H; Fujimura, S.
Staphylococci from samples of human saliva were isolated on staphylococcal-selective agar plates. These strains were tested for the inhibition of the growth of Staphylococcus aureus FDA209P. The frequency of inhibitory strains among all of the staphylococcal isolates was 5.2%. Strain IYS2, which formed the biggest inhibitory zone against the growth of the indicator strain, was used as the producer of bacteriocin. IYS2 was identified to be S. aureus, based on its biological properties. The bac...
Comparative Activities of Clinafloxacin, Grepafloxacin, Levofloxacin, Moxifloxacin, Ofloxacin, Sparfloxacin, and Trovafloxacin and Nonquinolones Linozelid, Quinupristin-Dalfopristin, Gentamicin, and Vancomycin against Clinical Isolates of Ciprofloxacin-Resistant and -Susceptible Staphylococcus aureus Strains
Jones, Mark E.; Visser, Maarten R.; Klootwijk, Miriam; Heisig, Peter; Verhoef, Jan; Schmitz, Franz-Josef
The activities of eight fluoroquinolones and linezolid, quinupristin-dalfopristin (Synercid), gentamicin, and vancomycin were tested against 96 ciprofloxacin-susceptible and 205 ciprofloxacin-resistant Staphylococcus aureus strains. Overall, clinafloxacin, followed by moxifloxacin and trovafloxacin, was the most active quinolone tested. For all isolates, linezolid and quinupristin-dalfopristin showed activities that were at least comparable to vancomycin, with no cross-resistance to any other...
Produção de enterotoxinas e da toxina da síndrome do choque tóxico por cepas de Staphylococcus aureus isoladas na mastite bovina Production of enterotoxins and toxic shock syndrome toxin by Staphylococcus aureus strains isolated from bovine mastitis
A. Nader Filho
Full Text Available A total of 72 strains of Staphylococcus aureus were examined for the production of staphylococcal enterotoxins (SE A, B, C, D and toxic shock syndrome toxin (TSST-1. The strains were isolated from milk samples from cows with mastitis in dairy herds of São Paulo State, Brazil. Off 72 isolates, 38 (52.8% produced SEA, 38 (52.8% SEB, 32 (44.4% SED, 28 (38.9% SEC and 27 (37.5% TSST-1. From the 72 strains, 66 (91.7% produced, at least, one or more toxin, including TSST-1.
Aarestrup, Frank Møller; Dangler, C. A.; Sordillo, L. M.
This study was conducted to investigate polymorphism of the coagulase gene of Staphylococcus aureus causing bovine mastitis. One hundred eighty-seven strains of S. aureus were isolated from bovine mastitic milk samples obtained from 187 different Danish dairy farms. The isolates were characterised...
Bardiau, Marjorie; Caplin, Jonathan; Detilleux, Johann; Graber, Hans; Moroni, Paolo; Taminiau, Bernard; Mainil, Jacques G
Staphylococcus (S.) aureus is recognised worldwide as an important pathogen causing contagious acute and chronic bovine mastitis. Chronic mastitis account for a significant part of all bovine cases and represent an important economic problem for dairy producers. Several properties (biofilm formation, intracellular survival, capsular expression and group agr) are thought to be associated with this chronic status. In a previous study, we found the existence of two groups of strains based on the association of these features. The aim of the present work was to confirm on a large international and non-related collection of strains the existence of these clusters and to associate them with case history records. In addition, the genomes of eight strains were sequenced to study the genomic differences between strains of each cluster. The results confirmed the existence of both groups based on capsular typing, intracellular survival and agr-typing: strains cap8-positive, belonging to agr group II, showing a low invasion rate and strains cap5-positive, belonging to agr group I, showing a high invasion rate. None of the two clusters were associated with the chronic status of the cow. When comparing the genomes of strains belonging to both clusters, the genes specific to the group "cap5-agrI" would suggest that these strains are better adapted to live in hostile environment. The existence of these two groups is highly important as they may represent two clusters that are adapted differently to the host and/or the surrounding environment. PMID:26931384
Jung, Byeong Su; Lee, Yong Ju; Lee, Na-Kyoung; Kim, Hyoun Wook; Oh, Mi-Hwa; Paik, Hyun-Dong
The aim of this study was to investigate the antimicrobial resistance profiles of and the enterotoxin gene distribution in 4 strains of Staphylococcus aureus (S10-2, S10-3, S12-2, and S13-2) isolated from 90 bulgogi samples. The S. aureus enterotoxin H gene (seh) was found in all the strains, while the S. aureus enterotoxin A gene (sea) was found only in 3 of the 4 strains. The S10-2 strain expressed a combination of enterotoxin genes - seg, seh, sei, sej, selm, and seln. The strains S10-2 an...
Gutiérrez, Diana; Rodríguez-Rubio, Lorena; García, Pilar; Billington, Craig; Premarante, Aruni; Rodríguez, Ana; Martínez, Beatriz
Bacteriophages (phages) are a promising tool for the biocontrol of pathogenic bacteria, including those contaminating food products and causing infectious diseases. However, the success of phage preparations is limited by the host ranges of their constituent phages. The phage resistance/sensitivity profile of eighty seven Staphylococcus aureus strains isolated in Spain and New Zealand from dairy, meat and seafood sources was determined for six phages (Φ11, K, ΦH5, ΦA72, CAPSa1 and CAPSa3). Most of the S. aureus strains were sensitive to phage K (Myoviridae) and CAPSa1 (Siphoviridae) regardless of their origin. There was a higher sensitivity of New Zealand S. aureus strains to phages isolated from both Spain (ΦH5 and ΦA72) and New Zealand (CAPSa1 and CAPSa3). Spanish phages had a higher infectivity on S. aureus strains of Spanish dairy origin, while Spanish strains isolated from other environments were more sensitive to New Zealand phages. Lysogeny was more prevalent in Spanish S. aureus compared to New Zealand strains. A multiplex PCR reaction, which detected ΦH5 and ΦA72 sequences, indicated a high prevalence of these prophages in Spanish S. aureus strains, but were infrequently detected in New Zealand strains. Overall, the correlation between phage resistance and lysogeny in S. aureus strains was found to be weak. PMID:27111797
Budri, P E; Silva, N C C; Bonsaglia, E C R; Fernandes Júnior, A; Araújo Júnior, J P; Doyama, J T; Gonçalves, J L; Santos, M V; Fitzgerald-Hughes, D; Rall, V L M
Bovine mastitis is an inflammation of the mammary glands of cows and causes significant economic losses in dairy cattle. Staphylococcus aureus is one of the microorganisms most commonly isolated. Novel agents are required in agricultural industries to prevent the development of mastitis. The production of biofilm by Staph. aureus facilitates the adhesion of bacteria to solid surfaces and contributes to the transmission and maintenance of these bacteria. The effect of the essential oils of Syzygium aromaticum (clove; EOSA) and Cinnamomum zeylanicum (cinnamon; EOCZ) and their major components, eugenol and cinnamaldehyde, on Staph. aureus biofilm formation on different surfaces was investigated. The results showed a significant inhibition of biofilm production by EOSA on polystyrene and stainless steel surfaces (69.4 and 63.6%, respectively). However, its major component, eugenol, was less effective on polystyrene and stainless steel (52.8 and 19.6%, respectively). Both EOCZ and its major component, cinnamaldehyde, significantly reduced biofilm formation on polystyrene (74.7 and 69.6%, respectively) and on stainless steel surfaces (45.3 and 44.9%, respectively). These findings suggest that EOSA, EOCZ, and cinnamaldehyde may be considered for applications such as sanitization in the food industry. PMID:26142866
Owens, W E
Bacterial L forms were isolated from milk samples of dairy cattle infected experimentally with Staphylococcus aureus. Initially, bacterial L forms were induced in vitro from 12 of 44 S. aureus strains isolated from bovine mastitis. Cows were experimentally infected in two experiments with strains shown in vitro to be easily inducible to L form and with S. aureus Newbould 305. Each quarter of the mammary gland was infected with either 10(3) or 10(6) CFU of the test strains. Treatment was initi...
Zhang, Lili; Li, Yuchen; Bao, Hongduo; Wei, Ruicheng; Zhou, Yan; Zhang, Hui; Wang, Ran
Staphylococcus aureus is a significant bacterial pathogen associated with bovine mastitis. The aim of the present study was to investigate and characterize of S. aureus strains isolated from the milk of cows suffering from mastitis in the mid-east of China. Among the 200 milk samples analyzed, 58 were positive for S. aureus, of these isolates, 11 isolates were methicillin-resistant Staphylococcus aureus (MRSA). All of the 58 S. aureus strains were classified in agr group I, while seven different sequence type (ST) patterns were identified and among them the most common was ST630 followed by ST188. All of the S. aureus isolates belonging to ST630 were resistant to more than four antimicrobials, and 22.2% of isolates belonging to ST188 were resistant to eight antimicrobials. Interestingly, while strong biofilm producers demonstrated higher resistance to multiple antimicrobials, they exhibited lower intracellular survival rates. The results of this study illustrated the distribution, antimicrobial susceptibility profiles, genotype, and the ability of biofilm production and mammary epithelial cells invasion of these S. aureus isolates. This study can provide the basis for the development of a disease prevention program in dairy farms to reduce the potential risk in both animal and human health. PMID:27265679
Musa, N. O.; Eltom, K.; Gessler, F.; H. Böhnel; Babiker, A.; Sanousi, S. M.
Staphylococcus aureus ssp anaerobius strain S10 was isolated from an outbreak of sheep abscess disease. Sequence of the catalase gene of this strain showed 99 % identity to the catalase gene (katB) sequence of the reference strain (S. aureus ssp. anaerobius strain MVF213) with mismatching of three base pairs. An important substitution located 1036 nucleotides upstream of the initiation codon from “C” in katB to “T” in the catalase gene of strain S10 originated a stop codon. The de...
Full Text Available In China, fosfomycin alone or in combination with other antibiotics is commonly used in the treatment of infections caused by Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA. Although fosfomycin-resistant S. aureus strains have continued to emerge and increase, the research on them is rare. In order to determine the prevalence and mechanisms of fosfomycin resistance in MRSA clinical isolates, a total of 96 non-duplicate MRSA isolates were collected from blood and cerebrospinal fluid samples at Huashan Hospital in Shanghai, China between 2004 and 2014. Antimicrobial susceptibility testing was performed by agar dilution. Meanwhile, the fosfomycin-resistance-related genes, fosB, murA, glpT, and uhpT, were amplified by PCR and subjected to sequencing analysis. Multilocus sequence typing (MLST was conducted to assess strain types. The minimum inhibitory concentration (MIC of fosfomycin for the 96 MRSA strains ranged from 1.0 to >1,024 mg/L, and approximately 70% (67/96 of the isolates were resistant to fosfomycin (MIC ≥ 64.0 mg/L. Nine isolates with MICs ≥ 128 mg/L carried fosB gene. Twenty-five distinct mutations were detected in the murA (7, glpT (10, and uhpT (8 genes. While five of the murA mutations and five of the glpT mutations were observed only in fosfomycin-sensitive isolates and one of the murA mutation was found both in fosfomycin-resistant and fosfomycin-sensitive isolates, the remaining 14 mutations (1 murA, 5 glpT, and all uhpT mutations were present only in fosfomycin-resistant isolates. MLST analysis demonstrated that the majority (46/67 of the glpT and/or uhpT mutants belong to ST5, the predominant sequence type among the fosfomycin-resistant MRSA isolates. In conclusion, there is a high rate of fosfomycin resistance in MRSA strains. The mutations in the murA, glpT, and uhpT genes are common in fosfomycin-resistant MRSA strains, and may play a greater role in the development of fosfomycin
Souza, Viviane; Nader Filho, Antonio; de Castro Melo, Poliana; Ferraudo, Guilherme Moraes; Antônio Sérgio, Ferraudo; de Oliveira Conde, Sandra; Fogaça Junior, Flavio Augusto
The epidemiological relationships between isolated Staphylococcus aureus strains in milk samples of dairy cows, reagent to California Mastitis Test, individual and group milk was demonstrated in different sites of the production fluxogram, in 12 milk-producing farms in the Gameleira region, municipality of Sacramento MG Brazil, so that localization and transmission modes may be identified. Two hundred and forty-four strains out of 446 samples collected at several sites were isolated and bio-chemically characterized as coagulase-positive staphylococcus. Specific chromosome DNA fragment of the species Staphylococcus aureus was amplified to 106 strains and 103 underwent (PFGE). Samples' collection sites with the highest isolation frequency of Staphylococcus aureus strains comprised papillary ostia (31.1%), CMT-reagent cow milk (21.7%), mechanical milking machines' insufflators (21,7%), milk in milk pails (6.6%) and the milk in community bulk tanks (5.6%). Genetic heterogeneity existed among the isolated 103 Staphylococcus aureus strains, since 32 different pulse-types were identified. Pulse-type 1 had the highest similarity among the isolated strains within the different sites of the milk-production fluxogram. Highest occurrence of pulsetype 1 isolates of Staphylococcus aureus strains was reported in samples collected from the papillary ostia (10.6%), followed by milk samples from CMT-reagent dairy cows (5.8%) and mechanical milking machine insufflators (3.8%). The above shows the relevance of these sites in the agents' transmission mechanism within the context of the farms investigated. PMID:24031997
Cosandey, A; Boss, R; Luini, M; Artursson, K; Bardiau, M; Breitenwieser, F; Hehenberger, E; Lam, Th; Mansfeld, M; Michel, A; Mösslacher, G; Naskova, J; Nelson, S; Podpečan, O; Raemy, A; Ryan, E; Salat, O; Zangerl, P; Steiner, A; Graber, H U
Staphylococcus aureus is globally one of the most important pathogens causing contagious mastitis in cattle. Previous studies, however, have demonstrated in Swiss cows that Staph. aureus isolated from bovine intramammary infection is genetically heterogeneous, with Staph. aureus genotype B (GTB) and GTC being the most prominent genotypes. In addition, Staph. aureus GTB was found to be contagious, whereas Staph. aureus GTC and all the remaining genotypes were involved in individual cow disease. The aim of this study was to subtype strains of Staph. aureus isolated from bovine mastitic milk and bulk tank milk to obtain a unified view of the presence of bovine staphylococcal subtypes in 12 European countries. A total of 456 strains of Staph. aureus were subjected to different typing methods: ribosomal spacer PCR, detection of enterotoxin genes, and detection of gene polymorphisms (lukE, coa). Major genotypes with their variants were combined into genotypic clusters (CL). This study revealed 5 major CL representing 76% of all strains and comprised CLB, CLC, CLF, CLI, and CLR. The clusters were characterized by the same genetic properties as the Swiss isolates, demonstrating high clonality of bovine Staph. aureus. Interestingly, CLB was situated in central Europe whereas the other CL were widely disseminated. The remaining 24% of the strains comprised 41 genotypes and variants, some of which (GTAM, GTBG) were restricted to certain countries; many others, however, were observed only once. PMID:26585469
Subhankari Prasad Chakraborty1, Santanu KarMahapatra1, Manjusri Bal2 and Somenath Roy1*
Full Text Available Staphylococcus aureus is most frequently isolated pathogen causing bloodstream infections, skin and soft tissue infections and pneumonia. Recently, S. aureus have evolved resistance to both synthetic and traditional antibiotics. This study was carried out to isolate pathogenic S. aureus from post-operative pus sample, and VRSA was identified by evaluation of resistance patterns using conventional antibiotics. Thirty post operative pus samples were collected from nearby Hospital and species identification was confirmed by Gram staining, standard biochemical tests and PCR amplification of the nuc gene. Antibiotic susceptibility tests were carried out by MIC, MBC, DAD test and BHI vancomycin screening agar. VRSA were confirmed by PCR amplification of the vanA and vanB genes. From this study, it was observed that isolated S. aureus strains are pathogenic; 30% of strains were resistant to penicillin G, ampicillin and erythromycin; 26.67% strains were resistant to cephotaxime, gentamycin, streptomycin, tetracycline, chloramphenicol, norfloxacin, methicillin and vancomycin.
Bouchard, Damien; Peton, Vincent; Almeida, Sintia; Le Maréchal, Caroline; Miyoshi, Anderson; Azevedo, Vasco; Berkova, Nadia; Rault, Lucie; Francois, Patrice; Schrenzel, Jacques; Even, Sergine; Hernandez, David; Le Loir, Yves
Staphylococcus aureus is a major etiological agent of mastitis in ruminants. We report here the genome sequence of bovine strain Newbould 305, isolated in the 1950s in a case of bovine mastitis and now used as a model strain able to reproducibly induce chronic mastitis in cows.
Nagel, M; Dischinger, J; Türck, M; Verrier, D; Oedenkoven, M; Ngoubangoye, B; Le Flohic, G; Drexler, J F; Bierbaum, G; Gonzalez, J-P
The risk of serious infections caused by Staphylococcus aureus is well-known. However, most studies regarding the distribution of (clinically relevant) S. aureus among humans and animals took place in the western hemisphere and only limited data are available from (Central) Africa. In this context, recent studies focused on S. aureus strains in humans and primates, but the question of whether humans and monkeys share related S. aureus strains or may interchange strains remained largely unsolved. In this study we aimed to evaluate the distribution and spread of human-like S. aureus strains among great apes living in captivity. Therefore, a primate facility at the International Centre for Medical Research of Franceville (Gabon) was screened. We detected among the primates a common human S. aureus strain, belonging to the spa-type t148. It was isolated from three different individuals of the western lowland gorilla (Gorilla gorilla gorilla), of which one individual showed a large necrotizing wound. This animal died, most probably of a staphylococcal sepsis. Additionally, we discovered the t148 type among chimpanzees (Pan troglodytes) that were settled in the immediate neighbourhood of the infected gorillas. A detailed analysis by pulsed field gel electrophoresis showed that the gorilla and chimpanzee isolates represented two closely related strains. To our knowledge, this is the first report of a human-associated S. aureus strain causing disease in great apes. The simultaneous detection in gorillas and chimpanzees indicated an interspecies transmission of this S. aureus strain. Our results recommend that protection of wild animals must not only be based on habitat conservation, but also on the assessment of the risk of contact with human pathogens. PMID:23398468
Baum, Cathrin; Haslinger-Löffler, Bettina; Westh, Henrik;
Staphylococcus aureus is a major human pathogen responsible for increasing the prevalence of community- and hospital-acquired infections. Protein A (SpA) is a key virulence factor of S. aureus and is highly conserved. Sequencing of the variable-number tandem-repeat region of SpA (spa typing......) provides a rapid and reliable method for epidemiological studies. Rarely, non-spa-typeable S. aureus strains are encountered. The reason for this is not known. In this study, we characterized eight non-spa-typeable bacteremia isolates. Sequencing of the entire spa locus was successful for five strains...... and revealed various mutations of spa, all of which included a deletion of immunoglobulin G binding domain C, in which the upper primer for spa typing is located, while two strains were truly spa negative. This is the first report demonstrating that nontypeability of S. aureus by spa sequencing is due either...
Baum, Cathrin; Haslinger-Löffler, Bettina; Westh, Henrik; Boye, Kit; Peters, Georg; Neumann, Claudia; Kahl, Barbara C
Staphylococcus aureus is a major human pathogen responsible for increasing the prevalence of community- and hospital-acquired infections. Protein A (SpA) is a key virulence factor of S. aureus and is highly conserved. Sequencing of the variable-number tandem-repeat region of SpA (spa typing......) provides a rapid and reliable method for epidemiological studies. Rarely, non-spa-typeable S. aureus strains are encountered. The reason for this is not known. In this study, we characterized eight non-spa-typeable bacteremia isolates. Sequencing of the entire spa locus was successful for five strains and...... revealed various mutations of spa, all of which included a deletion of immunoglobulin G binding domain C, in which the upper primer for spa typing is located, while two strains were truly spa negative. This is the first report demonstrating that nontypeability of S. aureus by spa sequencing is due either...
Donnio, Pierre-Yves; Février, Frédéric; Bifani, Pablo; Dehem, Marie; Kervégant, Christèle; Wilhelm, Nathalie; Gautier-Lerestif, Anne-Lise; Lafforgue, Nathalie; Cormier, Michel; Le Coustumier, Alain
The excision of the staphylococcal chromosomal cassette mec (SCCmec) from methicillin-resistant Staphylococcus aureus (MRSA) strains results in methicillin-susceptible S. aureus (MSSA) strains. In order to determine the proportion and diversity of multidrug-resistant MSSA (MR-MSSA) strains derived from MRSA strains, 247 mecA-negative isolates recovered in 60 French hospitals between 2002 and 2004 were characterized. The spa types of all strains were determined, and a subset of the strains (n = 30) was further genotyped by multilocus sequence typing. The IDI-MRSA assay was used to test the isolates for the presence of the SCCmec element, which was detected in 68% of all isolates analyzed. Molecular analysis of the samples suggested that 92% of the MR-MSSA isolates were derived from MRSA clones of diverse genetic backgrounds, of which the clone of sequence type 8 and SCCmec type IVA accounted for most of the samples. High variations in incidence data and differences in the molecular characteristics of the isolates from one hospital to another indicate that the emergence of MR-MSSA resulted from independent SCCmec excisions from epidemic MRSA isolates, as well as the diffusion of methicillin-susceptible strains after the loss of SCCmec. MR-MSSA could constitute a useful model for the study of the respective genetic and environmental factors involved in the dissemination of S. aureus in hospitals. PMID:17709473
Salvatore Virdis; Christian Scarano; Francesca Cossu; Vincenzo Spanu; Carlo Spanu; Enrico Pietro Luigi De Santis
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 C...
Kim, Bong-Soo; Yi, Hana; Chun, Jongsik; Cha, Chang-Jun
Background Staphylococcus aureus is a pathogen that causes food poisoning and community-associated infection with antibiotic resistance. This species is an indigenous intestinal microbe found in infants and not found in adult intestine. The relatively small genome size and rapid evolution of antibiotic resistance genes in the species have been drawing an increasing attention in public health. To extend our understanding of the species and use the genome data for comparative genomic studies, w...
Full Text Available Background: The optimal choice of antimicrobial therapy is an important problem in hospital environment in which the selection of resistant and virulent strains easy occurs. S. aureus and especially MRSA(methicillin-resistant S. aureus creates difficulties in both treatment and prevention of nosocomial infections. Aim: The purpose of this study is to determine the sensitivity and the resistance to chemotherapy of staphylococci strains isolated from various pathological products. Material and Method: We identified Staphylococccus species after morphological appearance, culture properties, the production of coagulase, hemolisines and the enzyme activity. The susceptibility tests were performed on Mueller-Hinton medium according to CLSI (Clinical and Laboratory Standards Institute. Results: The strains were: MSSA (methicillin-susceptible S. aureus (74%, MRSA (8%, MLS B (macrolides, lincosamides and type B streptogramines resistance (12% and MRSA and MLS B (6%. MRSA strains were more frequently isolated from sputum. MRSA associated with the MLS B strains were more frequently isolated from pus. MLS B strains were more frequently isolated from sputum and throat secretions. All S. aureus strains were susceptible to vancomycin and teicoplanin. Conclusions: All staphylococcal infections require resistance testing before treatment. MLS B shows a high prevalence among strains of S. aureus. The association between MLS B and MRSA remains a major problem in Romania.
Full Text Available Pseudomonas aeruginosa and Staphylococcus aureus are the most prevalent pathogens in airway infections of cystic fibrosis (CF patients. We studied how these pathogens coexist and interact with each other. Clinical isolates of both species were retrieved from adult CF patients. Culture supernatants from 63 P. aeruginosa isolates triggered a wide range of biofilm-stimulatory activities when added to the culture of a control S. aureus strain. The extent of biofilm formation by S. aureus was positively correlated to the levels of the 2-alkyl-4-(1H-quinolones (AQs Pseudomonas Quinolone Signal (PQS and 2-heptyl-4-hydroxy quinoline N-oxide (HQNO produced by the P. aeruginosa isolates. Supernatants from P. aeruginosa isogenic mutants deficient in PQS and HQNO production stimulated significantly less biofilm formation by S. aureus than that seen with the parental strain PA14. When studying co-isolated pairs of P. aeruginosa and S. aureus retrieved from patients showing both pathogens, P. aeruginosa supernatants stimulated less biofilm production by the S. aureus counterparts compared to that observed using the control S. aureus strain. Accordingly, some P. aeruginosa isolates produced low levels of exoproducts and also some of the clinical S. aureus isolates were not stimulated by their co-isolates or by PA14 despite adequate production of HQNO. This suggests that colonization of the CF lungs promotes some type of strain selection, or that co-existence requires specific adaptations by either or both pathogens. Results provide insights on bacterial interactions in CF.
Watts, Andrew; Ke, Danbing; Wang, Qun; Pillay, Anil; Nicholson-Weller, Anne; Lee, Jean C.
Most isolates of Staphylococcus aureus produce a serotype 5 (CP5) or 8 (CP8) capsular polysaccharide. To investigate whether CP5 and CP8 differ in their biological properties, we created isogenic mutants of S. aureus Reynolds that expressed CP5, CP8, or no capsule. Biochemical analyses of CP5 and CP8 purified from the isogenic S. aureus strains were consistent with published structures. The degree of O acetylation of each polysaccharide was similar, but CP5 showed a greater degree of N acetyl...
Jung, Byeong Su; Lee, Yong Ju; Lee, Na-Kyoung; Kim, Hyoun Wook; Oh, Mi-Hwa; Paik, Hyun-Dong
The aim of this study was to investigate the antimicrobial resistance profiles of and the enterotoxin gene distribution in 4 strains of Staphylococcus aureus (S10-2, S10-3, S12-2, and S13-2) isolated from 90 bulgogi samples. The S. aureus enterotoxin H gene (seh) was found in all the strains, while the S. aureus enterotoxin A gene (sea) was found only in 3 of the 4 strains. The S10-2 strain expressed a combination of enterotoxin genes - seg, seh, sei, sej, selm, and seln. The strains S10-2 and S13-2 were resistant to ampicillin and penicillin G, and all the isolated strains were resistant to tetracycline. The S10-2 strain was the only mecA-positive strain; it was also resistant to β-lactam antibiotics. Thus, genes encoding enterotoxin as well as those conferring antibiotic resistance were identified in the S. aureus strains isolated from pork bulgogi. These results represents the potential occurrence of MRSA in pork bulgogi, and the need for a monitoring system for pork bulgogi in order to prevent an outbreak of staphylococcal food poisoning. PMID:26761872
Dittmann, Karen Kiesbye; Chaul, Luiza; Lee, Sarah;
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...... hygiene practices can be limited. The aim of this study was to determine if Brazilian dairy plants were contaminated by S. aureus, and if any clones were persistent. Four dairy plants were sampled during 8 months (398 samples in total). S. aureus (n=66) was found in all the dairy plants...... presumptive methicillin-sensitive S. aureus. All of the isolates expressed hemolytic activity. The frequent isolation of CC1 strains in Brazilian dairy plants indicates, despite antibiotic sensitivity, a potential health risk to the human consumer....
Johler, Sophia; Stephan, Roger; Althaus, Denise; Ehling-Schulz, Monika; Grunert, Tom
Staphylococcus aureus causes a variety of serious illnesses in humans and animals. Subtyping of S. aureus isolates plays a crucial role in epidemiological investigations. Metabolic fingerprinting by Fourier-transform infrared (FTIR) spectroscopy is commonly used to identify microbes at species as well as subspecies level. In this study, we aimed to assess the suitability of FTIR spectroscopy as a tool for S. aureus subtyping. To this end, we compared the subtyping performance of FTIR spectroscopy to other subtyping methods such as pulsed field gel electrophoresis (PFGE) and spa typing in a blinded experimental setup and investigated the ability of FTIR spectroscopy for identifying S. aureus clonal complexes (CC). A total of 70 S. aureus strains from human, animal, and food sources were selected, for which clonal complexes and a unique virulence and resistance gene pattern had been determined by DNA microarray analysis. FTIR spectral analysis resulted in high discriminatory power similar as obtained by spa typing and PFGE. High directional concordance was found between FTIR spectroscopy based subtypes and capsular polysaccharide expression detected by FTIR spectroscopy and the cap specific locus, reflecting strain specific expression of capsular polysaccharides and/or other surface glycopolymers, such as wall teichoic acid, peptidoglycane, and lipoteichoic acid. Supervised chemometrics showed only limited possibilities for differentiation of S. aureus CC by FTIR spectroscopy with the exception of CC45 and CC705. In conclusion, FTIR spectroscopy represents a valuable tool for S. aureus subtyping, which complements current molecular and proteomic strain typing. PMID:27021524
Nam, Hyang-Mi; Lee, Ae-Li; Jung, Suk-Chan; Kim, Mal-Nam; Jang, Geum-Chan; Wee, Sung-Hwan; Lim, Suk-Kyung
A total of 402 Staphylococcus aureus isolates from bovine mastitis milk collected during 2003-2009 in Korea were tested for susceptibility to 20 antimicrobial agents. All S. aureus isolates were susceptible to 11 of 20 antimicrobials tested; no resistance was observed against pirlimycin, telithromycin, novobiocin, penicillin/novobiocin, quinupristin/dalfopristin, clindamycin, rifampin, ciprofloxacin, trimethprim/sulfamethoxazol, vancomycin, and linezolid. Over 66% of the S. aureus isolates were resistant to penicillin. Resistance was also seen for gentamicin (11.9%), erythromycin (7.7%), methicillin (oxacillin and cefoxitin, 6.2%), and tetracycline (4.2%). No noticeable change was observed in penicillin, gentamicin, and erythromycin resistance over the 7-year period. Tetracycline resistance appeared to decrease consistently, whereas methicillin resistance was observed from 2005. About 2.7% (11/402) were resistant to three or more antimicrobials. Genotyping of the 17 methicillin-resistant S. aureus (MRSA) isolated from each cow revealed two staphylococcal cassette chromosome mec (SCCmec) types (IV and IVa), three spa types (t286, t324, and untypable), and two sequence types (ST1 and ST72). Eleven of 17 (64.7%) MRSA strains belonged to SCCmec IVa-t324-ST72. The rest of strains belonged to SCCmec IVa-t286-ST1 (n = 3) and SCCmec IV-untypable-ST72 (n = 3). None of the MRSA carried the Panton-Valentine leukocidin gene. These characteristics are the same as those found in community-acquired (CA) MRSA strains prevalent in humans in Korea. Three pulsed-field gel electrophoresis types (A-C) were observed among the 17 MRSA strains examined, and 14 strains belonged to the same pulsed-field gel electrophoresis pattern regardless of their geographical origin and year of isolation. The results of this study provide evidence of CA-MRSA infection in dairy cattle for the first time in Korea. PMID:21034263
苏洋; 蒲万霞; 邓海平; 李春慧; 梁红雁; 陈智华
本研究旨在了解甘肃地区奶牛乳房炎金黄色葡萄球菌的耐药性和耐甲氧西林金黄色葡萄球菌的感染情况,为奶牛乳房炎的防制提供理论依据.采用KB纸片扩散法,检测17株金黄色葡萄球菌对8种不同抗菌药物的敏感性；再用琼脂稀释法检测了苯唑西林、万古霉素对金黄色葡萄球菌的最小抑菌浓度(MICs)；头孢西丁纸片扩散法和PCR扩增特异性mecA耐药基因对所有受试菌株进行全面的耐甲氧西林金黄色葡萄球菌检测.结果表明,菌株对青霉素、磺胺异恶唑具有较强抗性,而对环丙沙星、头孢唑啉、万古霉素和苯唑西林全敏感；头孢西丁纸片扩散法未能检测出表型为MRSA的阳性菌株,而PCR方法却检测出8株mecA基因阳性菌株,且这些菌株的苯唑西林MIC均小于2μg/mL.菌株的耐药情况较严重,对甲氧西林敏感而携带mecA基因的菌株高频存在于被调查地区的奶牛场中.%The aim of present study was to investigate the antimicrobial resistance, and the prevalence of methicillin-resistant Staphylococcus aureus (S. aureus) isolated from bovine mastitis in Gansu province, to provide credible theory evidence for prevention and treatment on bovine mastitis. Eight commonly used antimicrobial agents were used for determining antimicrobial susceptibility of 17 total S. aureus strains by disk diffusion method. Agar screen method was used for determining the oxacil-lin and vancomycin minimum inhibitory concentration value as well. Disk diffusion method using the cephamycin antibiotics ce-foxitin and detection of mecA gene by PCR assay were performed to detect the presence of MRSA. Most of strains showed a high resistance for penicillin and sulfafurazole, yet keeping complete sensitivity for ciprofloxacin, cefazolin, vancomycin and ox-acillin. None MRS A isolate was identified by the phenotypic detection method, but eight MRSA isolates with the MIC of oxac-illin lower than 2 μg/mL were
De Oliveira, A. P.; Watts, J. L.; Salmon, S. A.;
Minimum inhibitory concentrations were determined for 811 strains of Staphylococcus aureus isolated from cases of bovine mastitis in 11 countries. The countries and number of isolates included Denmark (105), England (92), Finland (95), Germany (103), Iceland (22), Ireland (42), Norway (101), Swed...... antimicrobial agents tested regardless of country. Given the differences in antimicrobial use in various countries, the widespread adoption of mastitis control programs to prevent infections limits the exposure of S. aureus infected animals to antimicrobial drugs.......Minimum inhibitory concentrations were determined for 811 strains of Staphylococcus aureus isolated from cases of bovine mastitis in 11 countries. The countries and number of isolates included Denmark (105), England (92), Finland (95), Germany (103), Iceland (22), Ireland (42), Norway (101), Sweden...
Detecção da toxina-1 da síndrome do choque tóxico em amostras de Staphylococcus aureus isoladas de mastite bovina Detection of toxic shock syndrome toxin by Staphylococcus aureus strains isolated from bovine mastitis
Full Text Available Este trabalho teve por objetivo caracterizar a produção da toxina da síndrome do choque tóxico (TSST-1 e de enterotoxinas estafilocócicas (SE A, B, C e D em 127 amostras de S. aureus, isoladas de amostras de leite proveniente de vacas com mastite no Estado de Minas Gerais, entre 1994 e 1997. A verificação da produção de toxinas foi feita pela técnica de sensibilidade ótima em placa. Das 127 amostras testadas, 60 (47% eram produtoras de TSST-1 e 54 (43% produtoras de SE, 38 amostras produziram SED (30%, 24 SEB (19%, 8 SEC (6% e 4 SEA (3%. Estes resultados trazem preocupações quanto à saúde pública pela alta prevalência de amostras de S. aureus produtoras de TSST-1 e de enterotoxinas em isolamentos a partir de leite de vacas com mastite.A total of 127 strains of Staphylococcus aureus were examined for the production of toxic shock syndrome toxin (TSST-1 and staphylococcal enterotoxins (SE A, B, C and D. The strains were isolated from milk samples from cows with mastitis in dairy herds of Minas Gerais State, Brazil, from 1994 to 1997. The toxins were detected using the optimum-sensitivity plate method. Of 127 isolates, 60 (47% produced TSST-1 and 54 (43% produced SE, 38 (30% produced SED, 24 (19% SEB, 8 (6% SEC and 4 (3% enterotoxin A..
Atividade antibacteriana de óleos essenciais de plantas frente a linhagens de Staphylococcus aureus e Escherichia coli isoladas de casos clínicos humanos Antibacterial activity of plant essential oils against Staphylococcus aureus and Escherichia coli strains isolated from human specimens
Full Text Available A ação antibacteriana in vitro de óleos essenciais de seis plantas foi verificada por meio da Concentração Inibitória Mínima (CIM=%v/v pela diluição dos óleos em meio de cultura Mueller Hinton Agar, frente a linhagens de Staphylococcus aureus (n=16 e Escherichia coli (n=16 isoladas de casos clínicos humanos, além de 1 amostra padrão ATCC para cada espécie (Sa ATCC 25923 e Ec ATCC 25922, e determinação de curvas de sobrevivência em concentrações equivalentes a CIM90% dos respectivos óleos. O óleo essencial de canela foi o mais eficiente, com valores de CIM90% de 0,047 e 0,09 para S. aureus e E. coli respectivamente, enquanto gengibre (0,09, cravo da índia (0,095 e capim cidreira (0,1 apresentaram eficiências semelhantes para S. aureus. Frente a E. coli, os óleos de gengibre (0,52 e capim cidreira (0,55 foram equivalentes quanto à eficiência. De acordo com as curvas de sobrevivência, foi possível verificar também que os valores de CIM90% obtidos podem ser tanto bactericidas ou bacteriostáticas de acordo com a bactéria testada. Em conclusão, verificou-se que os óleos essenciais testados foram efetivos no controle do desenvolvimento bacteriano, sendo o potencial antimicrobiano diferente em função da espécie bacteriana testada, sendo que a bactéria Gram positiva (S. aureus mostrou-se mais susceptível aos óleos testados que a Gram negativa (E. coli.The in vitro antibacterial activity of essential oils from six plants was verified through minimal inhibitory concentration (MIC=%v/v, determined by diluting the oils in culture medium Mueller Hinton Agar, against Staphylococcus aureus (n=16 and Escherichia coli (n=16 strains isolated from human clinical specimens, besides one standard ATCC strain for each species (Sa 25923 and Ec 25922. Time-kill curves were also determined at concentrations equivalent to MIC90% for the respective oils. Cinnamon oil was the most efficient, with MIC90% values of 0.047 and 0.09 against
Morteza Shojaei Moghadam; Susan Maleki; Esmaeil Darabpour; Hossein Motamedi; Seyyed Mansour Seyyed Nejad
Objective:To assess the antibacterial activity of eight Iranian plant extracts against Staphylococcus aureus (S. aureus)strains which were isolated from infected patients.Methods:The studied strains were isolated from urine, stool, blood and wound of infected patients and identified by biochemical tests. In further, the antibacterial activity of 8 ethanolic local plant extracts includingQuerqus brantii (Q. brantii),Ziziphus spina-christi (Z. spina-christi),Peganum harmala(P. harmala),Oliveira decumbens (O. decumbens),Galium tricornutum(G. tricornutum), Vitex pseudonegundo (Vi. pseudo negundo),Salvia officinalis (S. officinalis) ,Vaccaria pyramidata (V.pyramidata)were then evaluated using agar disc diffusion method.Results:A total of 9 isolates were isolated and identified asS. aureus. Antibacterial profile of the strains showed that the strains were resistant to methicillin and cefixime. The highest antibacterial activity against the studied strains were belong toQ. brantii,P. harmala,Z. spina-christi andO. decumbens vent extracts with 11-40 mm, 15-28 mm, 8-26 mm and 10-20 mm of diameters, respectively. Intermediate antibacterial activity was exhibited byG. tricornutum andVi. pseudo negundo against some of the studied strains with 7-20 mm and 7-13 mm of diameters, respectively. Noteworthy, out of 9 studied strains; 6 and 2 of them were resistant to theG. tricornutum andVi. pseudo negundo extracts, respectively. TheS. officinalis andVa. pyramidata, however, showed no antibacterial activity against the studied strains.Conclusions: TheQ. brantii,P. harmala,Z. spina-christi andO. decumbens extracts were shown to possess strong antibacterial activity against methicillin and cefixime resistant S. aureus strains and can be considered as the promising natural antibiotics for treating the studied strains.
Snel, Gustavo G M; Monecke, Stefan; Ehricht, Ralf; Piccinini, Renata
The biofilm-associated protein (Bap) of Staphylococcus aureus is a high molecular weight cell-wall-anchored protein involved in biofilm formation, first described in bovine mastitis strains from Spain. So far, studies regarding Bap were mainly based on the Spanish strain V329 and its mutants, but no information on the genetic variability of bap-positive Staph. aureus strains is yet available in the literature. The present study investigated the molecular characteristics of 8 bap-positive Staph. aureus strains from subclinical bovine mastitis, isolated in 5 herds; somatic cell counts (SCC) of milk samples were also registered. Strains were characterised using MLST, SPA typing and microarray and the results were compared with V329. All isolates from this study and V329 were assigned to ST126, t605, but some molecular differences were observed. Only herd A and B strains harboured the genes for β-lactams resistance; the leukocidin D/E gene, a type I site-specific deoxyribonuclease subunit, 3rd locus gene and serin-protease A and B were carried by all strains, but not by V329, while serin-protease E was absent in V329 and in another isolate. Four isolates and V329 harboured the fibronectin-binding protein B gene. SCC showed the highest value in the milk sample affected by the only strain carrying all the virulence factors considered. Potential large variability of virulence was evidenced among V329 and all bap-positive Staph. aureus strains considered: the carriage of fnb could enhance the accumulation of biofilm, but the lack of lukD/E and splA, B or E might decrease the invasiveness of strain. PMID:25850658
Full Text Available Objective: The present study investigated phenotypes, virulence genotypes, and antibiotic susceptibility of oral Staphylococcus aureus strains in order to get more information on whether oral infections with this bacterium are associated with certain subtypes or related to an over-growth of the S. aureus variants normally found in the oral cavity of healthy carriers. Materials and methods: A total number of 157 S. aureus strains were investigated. Sixty-two strains were isolated from Swedish adults with oral infections, 25 strains were from saliva of healthy Swedish dental students, and 45 strains were from tongue scrapings of HIV-positive subjects in Thailand, and 25 Thai strains from non-HIV controls. The isolates were tested for coagulase, nitrate, arginine, and hemolysin, and for the presence of the virulence genes: hlg, clfA, can, sdrC, sdrD, sdrE, map/eap (adhesins and sea, seb, sec, tst, eta, etb, pvl (toxins. MIC90 and MIC50 were determined by E-test against penicillin V, oxacillin, amoxicillin, clindamycin, vancomycin, fusidic acid, and cefoxitin. Results: While the hemolytic phenotype was significantly (p<0.001 more common among the Thai strains compared to Swedish strains, the virulence genes were found in a similar frequency in the S. aureus strains isolated from all four subject groups. The Panton-Valentine leukocidin (PVL genotype was found in 73–100% of the strains. More than 10% of the strains from Swedish oral infections and from Thai HIV-positives showed low antibiotic susceptibility, most commonly for clindamycin. Only three methicillin-resistant S. aureus (MRSA strains were identified, two from oral infections and one from a Thai HIV patient. Conclusions: S. aureus is occasionally occurring in the oral cavity in both health and disease in Sweden and Thailand. It is therefore most likely that S. aureus in opportunistic oral infections originate from the oral microbiota. S. aureus should be considered in case of oral
Full Text Available Background Methicillin-resistant Staphylococcus aureus (MRSA is a well-known pathogen that causes serious diseases in humans. As part of the efforts to control this pathogen, an isolated bacteriophage, Siphoviridae, which specifically targets Methicillin-resistant Staphylococcus aureus (MRSA, was characterized. Aims The objective of this study was to characterize of a virulent bacteriophage (Siphoviridae isolated from a NICU bathroom sink. Methods The MRSA strain was isolated from patient blood. The isolated strain was confirmed as MRSA using conventional methods. Phages were isolated from a NICU bathroom sink and activity was lytic as determined by spot test. Titer phage lysate was measured by the Double Layer Agar (DLA technique. The morphology was found with electron microscopy. The single-step growth curve was plotted. Results Electron microscopy showed the phage as a member of the family Siphoviridae, serogroup A and F. The isolated phage was capable of lytic activity against methicillin-resistant Staphylococcus aureus (MRSA strain as shown by spot test. By DLA, the titre of the phages was determined to be 10×108PFU/ml. The single-step growth curve showed that the latent period of the isolated bacteriophage was 30 min and the total number of viable progeny per infected host, burst size, was 2600 PFU/infected host. Conclusion In this study, two phages were isolated and characterized from a NICU bathroom sink, from the Siphoviridae family, which specifically targetsmethicillin-resistant Staphylococcus aureus (MRSA.
Musa, N O; Eltom, K; Gessler, F; Böhnel, H; Babiker, A; El Sanousi, S M
Staphylococcus aureus ssp anaerobius strain S10 was isolated from an outbreak of sheep abscess disease. Sequence of the catalase gene of this strain showed 99% identity to the catalase gene (katB) sequence of the reference strain (S. aureus ssp. anaerobius strain MVF213) with mismatching of three base pairs. An important substitution located 1036 nucleotides upstream of the initiation codon from "C" in katB to "T" in the catalase gene of strain S10 originated a stop codon. The deduced protein (345 amino acids) is 105 amino acids shorter than that of katB. Partial sequence of the catalase gene of other 8 local isolates in addition to another reference strain (DSM 20714/ATCC 35844) revealed the same mutations in all local (African) strains, whereas the sequence of the reference (European) strain was typical to that of katB. Sequence of the catalase gene of S. aureus ssp. anaerobius strain S10 was deposited in GenBank under accession no. EU281993. PMID:20526831
Spanu, Vincenzo; Scarano, Christian; Virdis, Salvatore; Melito, Sara; Spanu, Carlo; De Santis, Enrico Pietro Luigi
The presence of Staphylococcus aureus in raw milk can represent a potential threat to human health, due to the introduction of pathogenic strains into dairy food supply chain. The present study was performed to investigate the genetic variation among S. aureus strains isolated from bulk tank goat's milk. The virulence profiles were also assessed to link the isolates with the potential source of milk contamination. A population study was performed on 60 strains using distance-based methods such as pulsed-field gel electrophoresis (PFGE), and the output was analyzed using Structure statistical software (University of Chicago; http://pritch.bsd.uchicago.edu/structure.html ). This Bayesian clustering model tool allows one to assign individuals into a population with no predefined structure. In order to assess partition of genetic variability among isolates, groups obtained by Structure were also investigated using analysis of molecular variance. S. aureus was recovered in 60 out of 78 samples (76.9%) collected from 26 farms. According to PFGE analysis, the strains were divided into 25 different pulsotypes and grouped into two main clusters. Restriction profiles, analyzed by Structure, allowed us to identify two distinct S. aureus genetic groups. Within each group, the strains showed a high coefficient of membership. A great part of genetic variability was attributable to within-groups variation. On the basis of the virulence profile, 45% of the isolates were linked to "animal" biovar, while 6.7% could be assigned to "human" biovar. Out of 60 strains, 27 were characterized by in vitro production of either enterotoxins A (5.0%), C (38.3%), or D (1.7%). The present study showed a high prevalence of bulk tank goat's milk contamination with S. aureus of animal origin. The presence in goat's milk of S. aureus strains able to produce enterotoxins and their potential introduction into dairy chain may represent a serious threat to human health. PMID:23458027
Ote, Isabelle; Taminiau, Bernard; Duprez, Jean-Noël; Dizier, Isabelle; Mainil, Jacques G
Staphylococcus aureus is recognized worldwide as a pathogen causing many serious diseases in humans and animals, and is the most common aetiological agent of clinical and subclinical bovine mastitis. The importance of evaluating the combination of S. aureus virulence factors has been emphasized both in human and veterinary medicine, and knowledge about the genetic variability within different S. aureus populations would help in the design of efficient treatments. The aim of the present study was to determine the genetic profiles of S. aureus strains isolated from milk of cows suffering from clinical and subclinical mastitis in Belgium. The presence of about forty virulence-associated genes was investigated by specific polymerase chain reaction (PCR) amplification. A high number of genotypic subtypes were observed, demonstrating further the large variation in the presence of virulence genes in S. aureus isolates and the considerable diversity of strains populations that are able to cause mastitis in cows. In accordance with other studies, we showed that some genes are associated with mastitis-causing S. aureus isolates, whereas others are absent or rarely present. We also further highlighted the presence of conserved gene combinations, namely the enterotoxigenic egc-cluster and the bovine pathogenicity island SaPIbov. Importantly, the presence of isolates carrying genes coding for toxins involved in important human infections makes the milk of cows with mastitis a potential reservoir for these toxins, and therefore a potential danger in human health, which strengthens the importance to consider raw milk consumption and its processing very carefully. PMID:21708435
Full Text Available The epidemiological relationships between isolated Staphylococcus aureus strains in milk samples of dairy cows, reagent to California Mastitis Test, individual and group milk was demonstrated in different sites of the production fluxogram, in 12 milk-producing farms in the Gameleira region, municipality of Sacramento MG Brazil, so that localization and transmission modes may be identified. Two hundred and forty-four strains out of 446 samples collected at several sites were isolated and bio-chemically characterized as coagulase-positive staphylococcus. Specific chromosome DNA fragment of the species Staphylococcus aureus was amplified to 106 strains and 103 underwent (PFGE. Samples' collection sites with the highest isolation frequency of Staphylococcus aureus strains comprised papillary ostia (31.1%, CMT-reagent cow milk (21.7%, mechanical milking machines' insufflators (21,7%, milk in milk pails (6.6% and the milk in community bulk tanks (5.6%. Genetic heterogeneity existed among the isolated 103 Staphylococcus aureus strains, since 32 different pulse-types were identified. Pulse-type 1 had the highest similarity among the isolated strains within the different sites of the milk-production fluxogram. Highest occurrence of pulsetype 1 isolates of Staphylococcus aureus strains was reported in samples collected from the papillary ostia (10.6%, followed by milk samples from CMT-reagent dairy cows (5.8% and mechanical milking machine insufflators (3.8%. The above shows the relevance of these sites in the agents' transmission mechanism within the context of the farms investigated.
Martins, Katheryne Benini; Faccioli-Martins, Patricia Yoshida; Riboli, Danilo Flávio Moraes; Pereira, Valéria Cataneli; Fernandes, Simone; Oliveira, Aline A; Dantas, Ariane; Zafalon, Luiz Francisco; da Cunha, Maria de Lourdes Ribeiro de Souza
The objective of this study was to characterize the clonal profile, virulence factors and antimicrobial resistance, particularly oxacillin resistance, of Staphylococcus aureus isolated from sheep milk. Milk samples were collected from all teats for the California Mastitis Test (CMT), somatic cell count, identification of S. aureus, investigation in these strains of genes encoding toxins (sea, seb, sec, sed, tst), biofilm (icaA, icaC, icaD, bap), leukocidin (luk-PV) oxacillin resistance by mecA gene detection and susceptibility testing (12 antibiotics). Messenger RNA expression was evaluated by RT-PCR in isolates carrying toxin and biofilm genes. Biofilm formation was also evaluated phenotypically by adherence to polystyrene plates. The clonal profile of S. aureus was investigated by pulsed-field gel electrophoresis. A total of 473 milk samples were collected from 242 animals on three farms and 20 S. aureus strains were isolated and none carried the mecA gene. The two sec gene-positive isolates and the isolates carrying the tst and luk-PV genes were positive by RT-PCR. Staphylococcus aureus isolated from the three flocks studied showed high susceptibility to the drugs tested and none was biofilm producer, indicating that biofilm formation was not a virulence factor causing infection by these strains. The typing of 17 S. aureus isolates revealed the presence of a common clone on the three farms studied, and the presence and expression of the sec and tst genes in one strain of this clone suggest the possible acquisition of virulence genes by this clone, a fact that is important for animal health and food hygiene. PMID:26273271
Katheryne Benini Martins
Full Text Available The objective of this study was to characterize the clonal profile, virulence factors and antimicrobial resistance, particularly oxacillin resistance, of Staphylococcus aureus isolated from sheep milk. Milk samples were collected from all teats for the California Mastitis Test (CMT, somatic cell count, identification of S. aureus, investigation in these strains of genes encoding toxins (sea, seb, sec, sed, tst, biofilm (icaA, icaC, icaD, bap, leukocidin (luk-PV oxacillin resistance by mecA gene detection and susceptibility testing (12 antibiotics. Messenger RNA expression was evaluated by RT-PCR in isolates carrying toxin and biofilm genes. Biofilm formation was also evaluated phenotypically by adherence to polystyrene plates. The clonal profile of S. aureus was investigated by pulsed-field gel electrophoresis. A total of 473 milk samples were collected from 242 animals on three farms and 20 S. aureus strains were isolated and none carried the mecA gene. The two sec gene-positive isolates and the isolates carrying the tst and luk-PV genes were positive by RT-PCR. Staphylococcus aureus isolated from the three flocks studied showed high susceptibility to the drugs tested and none was biofilm producer, indicating that biofilm formation was not a virulence factor causing infection by these strains. The typing of 17 S. aureus isolates revealed the presence of a common clone on the three farms studied, and the presence and expression of the sec and tst genes in one strain of this clone suggest the possible acquisition of virulence genes by this clone, a fact that is important for animal health and food hygiene.
Full Text Available A total of 108 S. aureus isolates from 16 major hospitals located in 14 different provinces in China were characterized for the profiles of 18 staphylococcal enterotoxin (SE genes, 3 exfoliatin genes (eta, etb and etd, and the toxic shock syndrome toxin gene (tsst by PCR. The genomic diversity of each isolate was also evaluated by pulsed-field gel electrophoresis (PFGE, multilocus sequence typing (MLST, and accessory gene regulator (agr typing. Of these strains, 90.7% (98/108 harbored toxin genes, in which tsst was the most prevalent toxin gene (48.1%, followed by sea (44.4%, sek (42.6% and seq (40.7%. The see and etb genes were not found in any of the isolates tested. Because of high-frequency transfer of toxin gene-containing mobile genetic elements between S. aureus strains, a total of 47 different toxin gene combinations were detected, including a complete egc cluster in 19 isolates, co-occurrence of sea, sek and seq in 38 strains, and sec and sel together in 11 strains. Genetic typing by PFGE grouped all the strains into 25 clusters based on 80% similarity. MLST revealed 25 sequence types (ST which were assigned into 16 clonal complexes (CCs including 2 new singletons. Among these, 11 new and 6 known STs were first reported in the S. aureus strains from China. Overall, the genotyping results showed high genetic diversity of the strains regardless of their geographical distributions, and no strong correlation between genetic background and toxin genotypes of the strains. For genotyping S. aureus, PFGE appears to be more discriminatory than MLST. However, toxin gene typing combined with PFGE or MLST could increase the discriminatory power of genotyping S. aureus strains.
Olukoya, D K; Asielue, J O; Olasupo, N A; Ikea, J K
In an investigation into the problems of infections due to Staphylococcus aureus in Nigeria, 100 strains were isolated from various hospitals in Lagos. The strains were screened for the presence of plasmids and for susceptibility to antimicrobial agents. Plasmids were extracted by modification of the method of Takahashi and Nagono. The plasmids were diverse in nature. The strains were found to be highly resistant to commonly prescribed antibiotics. PMID:8669391
Larner-Svensson, Hanna; Worning, Peder; Bartels, Mette;
We report the genome sequence, in five contigs, of a methicillin-resistant Staphylococcus aureus isolate designated M1. This clinical isolate was from the index patient of a methicillin-resistant Staphylococcus aureus (MRSA) outbreak in Copenhagen, Denmark, that started in 2003. This strain is...
I.V. Babushkina; V.B. Borodulin; G.V. Korshunov; D.M. Puchinjan
Research objective is to study antibacterial action of nanoparticles of iron and copper on polyantibiotically resistant clinical Staphylococcus aureus strains. Materials and methods include antibacterial action of nanoparticles of copper and iron on 10 Staphylococcus au¬reus strains, isolated from patients with purulent complications stayed in the in-patient department of traumatology and orthopedics. Solutions of powders of iron and copper have been prepared directly before the experiment in...
Abazar Pournajaf; Abdollah Ardebili; Leyla Goudarzi; Mahmoud Khodabandeh; Tahmineh Narimani; Hassan Abbaszadeh
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.
Faezizadeh, Zohreh; Gharib, Amir; Godarzee, Masoud
Staphylococcus aureus is an opportunistic pathogen and remains a common cause of burn wound infections. Different studies have shown that entrapment of plant-derived compounds into liposomes could increase their anti-Staphylococcus aureus activity. Silymarin is the bioactive extract from the known plant Silybum marianum L. The objective of this study was to evaluate efficacy of silymarin in free and nanoliposomal forms against isolated methicillin-resistant Staphylococcus aureus (MRSA) strain...
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.
Full Text Available Different clones of methicillin-susceptible (MSSA and methicillin-resistant (MRSA Staphylococcus aureus have been found in humans as well as in animals and retail meat. However, more information about the genetic characteristics and similarities between strains is needed. The aim of this study was to identify and characterize Staphylococcus aureus from humans, and to compare their characteristics with isolates of animal origin. A total of 550 nasal swabs were taken from healthy humans, and S. aureus was isolated and identified. Positive S. aureus isolates were subjected to molecular typing and susceptibility testing. In addition, 108 MRSA isolates recovered from clinical patients in the state of North Dakota and 133 S. aureus isolates from animals and meat previously analyzed were included. The nasal carriage of S. aureus in healthy people was 7.6% and, in general, clones were genetically diverse. None of the S. aureus strains obtained from healthy people were mecA- or PVL-positive. A total of 105 (97.2% MRSA isolates from clinical cases harbored the mecA gene and 11 (10.2% isolated from blood stream infections harbored the PVL gene. The most common resistance profile among S. aureus from healthy people was penicillin, and from clinical cases were erythromycin-penicillin-ciprofloxacin. The rate of multidrug resistance (MDR was 70% in humans. Most of the S. aureus harboring mecA and PVL genes were identified as ST5 and ST8, and exhibited MDR. However, S. aureus isolates of animal origin used for comparison exhibited a lower rate of MDR. The most common resistance profiles in isolates of animal origin were penicillin-tetracycline and penicillin-tetracycline-erythromycin, in animals and raw meat, respectively. The ST5 was also found in animals and meat, with ST9 and ST398 being the major clones. The genetic similarity between clones from humans and meat suggests the risk of spread of S. aureus in the food chain.
Chaves, Fernando; García-Martínez, Jesus; Miguel, Sonia; Otero, Joaquín R.
A total of 15 of 101 (14.8%) nasal methicillin-resistant Staphylococcus aureus (MRSA) isolates exhibited mupirocin resistance (Mupr) compared with 1 of 154 (0.6%) methicillin-susceptible Staphylococcus aureus isolates. A total of 14 (93%) isolates exhibiting high-level Mupr belonged to a single clone. Horizontal plasmid transfer and transmission of Mupr strains contribute to a high incidence of Mupr MRSA at our institution.
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.
Hossein Motamedi; Hadis Mirzabeigi; Tahere Shirali
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.
Chen, Xu; Sun, Kangde; Dong, Danfeng; Luo, Qingqiong; Peng, Yibing; Chen, Fuxiang
Staphylococcus aureus, or methicillin-resistant S. aureus (MRSA), is a significant pathogen in both nosocomial and community infections. Community-associated MRSA (CA-MRSA) strains tend to be multi-drug resistant and to invade hospital settings. This study aimed to assess the antimicrobial resistance and molecular characteristicsof nasal S. aureus among newlyadmitted inpatients.In the present study, 66 S. aureus isolates, including 10 healthcare-associated MRSA (HA-MRSA), 8 CA-MRSA, and 48 methicillin-sensitive S. aureus (MSSA) strains, were found in the nasal cavities of 62 patients by screening 292 newlyadmitted patients. Antimicrobial resistance and molecular characteristics of these isolates, including spa-type, sequence type (ST) and SCCmec type, were investigated. All isolates were sensitive to linezolid, teicoplanin, and quinupristin/dalfopristin, but high levels of resistance to penicillin and erythromycin were detected. According to D-test and erm gene detection results, the cMLS(B) and iMLS(B) phenotypes were detected in 24 and 16 isolates, respectively. All 10 HA-MRSA strains displayed the cMLS(B) phenotypemediated by ermA or ermA/ermC, while the cMLS(B) CA-MRSA and MSSA strains carried the ermB gene. Molecular characterization revealedall 10 HA-MRSA strains were derived from the ST239-SCCmec III clone, and four out of eight CA-MRSA strains were t437-ST59-SCCmec V. The results suggest that patients play an indispensable role in transmitting epidemic CA-MRSA and HA-MRSA strains. PMID:26915614
A total of 108 S. aureus isolates from 16 hospitals located in 14 different provinces in China were characterized for the profiles of 19 staphylococcal enterotoxin (SE) genes by PCR and genotyped by PFGE and MLST. Of these strains, 88.9% (96/108) harbored SE genes, in which tsst was the most prevale...
Le Maréchal Caroline
Full Text Available Abstract Staphylococcus aureus is a major cause of mastitis in ruminants. In ewe mastitis, symptoms range from subclinical to gangrenous mastitis. S. aureus factors or host-factors contributing to the different outcomes are not completely elucidated. In this study, experimental mastitis was induced on primiparous ewes using two S. aureus strains, isolated from gangrenous (strain O11 or subclinical (strain O46 mastitis. Strains induced drastically distinct clinical symptoms when tested in ewe and mice experimental mastitis. Notably, they reproduced mild (O46 or severe (O11 mastitis in ewes. Ewe sera were used to identify staphylococcal immunoreactive proteins commonly or differentially produced during infections of variable severity and to define core and accessory seroproteomes. Such SERological Proteome Analysis (SERPA allowed the identification of 89 immunoreactive proteins, of which only 52 (58.4% were previously identified as immunogenic proteins in other staphylococcal infections. Among the 89 proteins identified, 74 appear to constitute the core seroproteome. Among the 15 remaining proteins defining the accessory seroproteome, 12 were specific for strain O11, 3 were specific for O46. Distribution of one protein specific for each mastitis severity was investigated in ten other strains isolated from subclinical or clinical mastitis. We report here for the first time the identification of staphylococcal immunogenic proteins common or specific to S. aureus strains responsible for mild or severe mastitis. These findings open avenues in S. aureus mastitis studies as some of these proteins, expressed in vivo, are likely to account for the success of S. aureus as a pathogen of the ruminant mammary gland.
Full Text Available The aim of the present study was to investigate the prevalence of S. aureus in raw sheep milk cheese and to assess the enterotoxigenic profile of the isolated strains. N.16 raw milk sheep cheese, collected from 8 artisan dairies, were analyzed to detect the presence of Coagulase Positive Staphylococci (CPS. In the frame of Regulation (EC No 2073/2005 cheese samples were tested for the presence of staphylococcal enterotoxins (SEs when a CPS count >105 cfu/g was detected. CPS isolates identified as S. aureus were analyzed using multiplex PCR for the detection of classical (sea-see and enterotoxins-like (seh, sek, sel, sem, seo, sep genes. S. aureus was recovered in all cheese samples and in 50% with levels >105 cfu/g. 14 strains carried at least one of the genes coding for enterotoxins. In none of the cheese samples SEs were detected. Although a correct acidification (pH 5.1-5.4 at 6 hours was observed in dairies using natural starter culture, in cheese samples obtained from these dairies, CPS counts were greater (P<0.05 as compared with those where starter culture were not used. This result might be related to the main role of microbial competition on the control of S. aureus in early stage of cheesemaking. Further research is needed to better understand the effect of lactic acid bacteria competition on the growth of S. aureus.
Fan, Frank; Yan, Kang; Wallis, Nicola G.; Reed, Shannon; Moore, Terrance D.; Rittenhouse, Stephen F.; DeWolf, Jr., Walter E.; Huang, Jianzhong; McDevitt, Damien; Miller, William H.; Seefeld, Mark A.; Newlander, Kenneth A.; Jakas, Dalia R.; Head, Martha S.; Payne, David J.
The MICs of triclosan for 31 clinical isolates of Staphylococcus aureus were 0.016 μg/ml (24 strains), 1 to 2 μg/ml (6 strains), and 0.25 μg/ml (1 strain). All the strains for which triclosan MICs were elevated (>0.016 μg/ml) showed three- to fivefold increases in their levels of enoyl-acyl carrier protein (ACP) reductase (FabI) production. Furthermore, strains for which triclosan MICs were 1 to 2 μg/ml overexpressed FabI with an F204C alteration. Binding studies with radiolabeled NAD+ demons...
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
Darban-Sarokhalil, Davood; Khoramrooz, Seyed Sajjad; Marashifard, Masoud; Malek Hosseini, Seyed Ali Asghar; Parhizgari, Najmeh; Yazdanpanah, Mahboobeh; Gharibpour, Farzaneh; Mirzaii, Mehdi; Sharifi, Bahman; Haeili, Mehri
Staphylococcus aureus remains a major cause of nosocomial infection worldwide. Characterization of S. aureus isolates circulating in the southwest of Iran will contribute to understand and control the spread of the strains in this area. spa and SCCmec typing methods were used for genotyping of 125 S. aureus isolates obtained from two teaching hospitals in Ahvaz. Drug susceptibility testing was performed by using disk diffusion method. Frequency of the methicillin resistant S. aureus (MRSA) isolates was 39% (n = 34) and 27% (n = 10) in Emam Khomeini and Golestan hospitals, respectively. Except for Erythromycin, MRSA strains showed high rate of resistance to antimicrobial agents including penicillin (100%), norfloxacine (80%), azitromycin (80%), ciprofloxacin (80%), gentamycin (77%), cotrimoxazole (75%), cephotaxime. All isolates were sensitive to vancomycin. Out of 44 MRSA strains, 39 (88.5%) were SCCmec III, three (7%) were IVc and two (4.5%) of them were nontypeable. spa types t037 (26 isolates; 59%), and t1149 (25 isolates; 31%) were the most dominant types found in MRSA and methicillin sensitive S. aureus (MSSA) strains, respectively. We found SCCmec type III as the most prominent type indicating that most of the studied bacterial population had hospital origin. spa type t037, the most frequent genotype in this study were significantly (100%) associated with MRSA. For the first time we are reporting spa types t692, t706 and t018 from Iran and t342, t704, t2622, t5598, t11270 and t2864 from Asia. Moreover we are reporting types t6871 and t2684 for the second time in the world. PMID:27392699
Full Text Available In the research work the results of the study of resistance forming to antibiotics, antiseptics and decametoxine composition with modified polysaccharides in S.aureus strains are presented. The development of resistance to penicillins, cephalosporins, glycopeptides, macrolides is shown. Slow forming of resistance to decasan and decametoxine composition with carboxymethylamylum, oxyethylcellulose was determined.
Full Text Available Abstract Background Staphylococcus aureus is a non-motile, gram positive, non-sporforming, facultative anaerobic microorganism. It is one of the important bacteria as a potential pathogen specifically for nosocomial infections. The sulfonamide derivative medicines are preferred to cure infection caused by S. aureus due to methicillin resistance. Methods Antimicrobial activity of four sulfonamide derivatives have been investigated against 50 clinical isolates of S. aureus and tested by using MIC and disc diffusion methods. 50 clinical isolate which collected from specimens of patients who are given medical treatment in Ondokuz Mayis University Medical School Hospital. A control strain of S. aureus ATCC 29213 was also tested. Results The strongest inhibition was observed in the cases of I [N-(2-hydroxy-4-nitro-phenyl-4-methyl-benzensulfonamid], and II [N-(2-hydroxy-5-nitro-phenyl-4-methyl-benzensulfonamid] against S. aureus. Compound I [N-(2-hydroxy-4-nitro-phenyl-4-methyl-benzensulfonamid] showed higher effect on 21 S. aureus MRSAisolates than oxacillin antibiotic. Introducing an electron withdrawing on the ring increased the antimicrobial activity remarkably. Conclusion This study may help to suggest an alternative possible leading compound for development of new antimicrobial agents against MRSA and MSSA resistant S. aureus. It was also shown here that that clinical isolates of 50 S. aureus have various resistance patterns against to four sulfonamide derivatives. It may also be emphasized here that in vitro antimicrobial susceptibility testing results for S. aureus need standardization with further studies and it should also have a correlation with in vivo therapeutic response experiments.
Sequence type 22 (ST22) and ST672 are the two major emerging clones of community-acquired methicillin-resistant Staphylococcus aureus in India. ST672 strains were found to cause severe ocular infections. We report the draft genome sequences of two emerging strains of methicillin-resistant S. aureus, AMRF1 (ST22) and AMRF2 (ST672), isolated from patients with ocular infections.
Aarestrup, Frank Møller; Wegener, Henrik Caspar; Jensen, N.E.;
This study was conducted to investigate the geographical distribution of phage and ribotypes of Staphylococcus aureus causing bovine mastitis in the 5 Nordic countries. A total of 403 isolates of S. aureus was isolated from 403 different dairy herds. One hundred five strains were isolated in...... the isolates of ribotype 1 belonged to phage type 29/52. This combined type accounted for 17% of all the 403 isolates. These findings show that a large number of different types of S. aureus can be isolated from cases of bovine mastitis. However, few types predominate within different countries. These...... predominating types seem to be specific in each country, however, a single type was common for both Denmark, Sweden and Finland. This could suggest differences in the virulence or in modes of transmission of predominating and rare types of S. aureus associated with bovine mastitis....
苏洋; 蒲万霞; 陈智华; 邓海平
[目的]了解内蒙古地区奶牛乳房炎金黄色葡萄球菌耐药性和耐甲氧西林金黄色葡萄球菌(MRSA)感染的情况,为奶牛乳房炎的防治提供理论依据.[方法]采用K-B纸片扩散法,检测分离自内蒙古地区38株金黄色葡萄球菌对17种药物的敏感性,同时用琼脂稀释法检测苯唑西林、万古霉素对金黄色葡萄球菌的最小抑菌浓度(MIC)；再用头孢西丁、苯唑西林纸片扩散法、苯唑西林盐琼脂筛选法和PCR方法扩增mecA耐药基因对分离菌株进行全面MRSA检测.[结果]分离菌株对每种抗生素都有不同程度抗性,对氨苄西林、头孢拉丁、青霉素、复方新诺明、新生霉素和链霉素的耐药率都高于45％,而对氧氟沙星、丁胺卡那霉素、万古霉素、环丙沙星、庆大霉素和头孢唑林的敏感性高于90％,2株细菌的万古霉素MIC≥16 μg.mL-1；其中8株细菌的苯唑西林MIC≥8μg·mL-1,而其它菌株的苯唑西林MIC≤2μg·mL-1,分离菌株多重耐药情况严重,耐受3种及3种以上药物的菌株占84.21％,其中4株细菌能同时耐受9种不同抗菌药物；16 (42.11％)株细菌被检测携带mecA耐药基因,而仅有其中7株的苯唑西林MIC≥4 μg·mL-1;头孢西丁、苯唑西林纸片扩散法和苯唑西林盐琼脂筛选法分别检出7株、10株和7株表型为MRSA的菌株.[结论]分离菌株的耐药性和多重耐药现象较为严重,被调查地区奶牛场中已经存在MRSA和OS-MRSA感染情况,且感染率高.%[Objective] The aim of the study is to investigate the antimicrobial resistance of S. aureus (Science) and to detect the presence of methicillin-resistant S. aureus (MRSA) among S. aureus strains isolated from bovine mastitis in Inner Mongolia, and to provide credible theory evidence for prevention and treatment of bovine mastitis. [Method] K-B.disk diffusion method was used to test drug sensitivity of 38 total strains of S.aureus to 17 commonly used antibiotics
Cuaron, Jesus A.; Dulal, Santosh; Cooke, Peter H.; Torres, Nathaniel; Gustafson, John E.
Tea tree oil-reduced susceptibility (TTORS) mutants of two Staphylococcus aureus laboratory strains were isolated utilizing TTO gradient plates. Attempts to isolate TTORS mutants employing agar plates containing single TTO concentrations failed. All TTORS mutants demonstrated a small colony variant (SCV) phenotype and produced cells with a smaller diameter, as determined by scanning electron microscopy. The addition of SCV auxotrophic supplements to media did not lead to an increase in TTORS ...
Full Text Available Background: Staphylococcus aureus (S. aureus is one of the major virulence factors of hospital and community acquired infections. Healthcare workers can be the host of S.aureus for many months. And it is very important due to the possibility of transmission to patients. Theaim of this study was to determine the prevalence of S.aureus nasal carriers, the antibiotic susceptibility pattern and its effective factors on Sina Hospital workers in Tehran, Iran.Methods: healthcare workers from different wards of Sina Hospital were studied in Tehran, Iran in 2010. Samples were taken from both nostrils of each individual. After 18-24hr incubation, the isolates were evaluated by gram stain, catalase, coagulase, DNase and manitol salt agar bywhich staphylococci were isolated. Disk diffusion antimicrobial susceptibility tests against oxacillin, cefoxitin and vancomycin was performed. Finally, by using PCR, the mecA gene was studied in methicillin-resistant strains (MRSA.Results: 34of the 166 workers, were nasal carriers of S. aureus and one of them was MRSA. The ratio of carriers in operating room workers was more than other wards, without significant relationship (p.value>0.05. S.aureus was found in 34.3% of operating room, 13.8% of nurses and 22.7% of licensed and other personnel. There was a significant relationship betweenoccupations and S.aureus carriage (p.value:0.03.Conclusion: According to the low prevalence of S. aureus and MRSA carriers in Sina hospital, it can be said that the role of the hospital staff as a source of infections caused by S. aureus especially is very low.
POUTREL, B.; Rainard, P; Sarradin, P.
It was reported previously that two capsular polysaccharides, types 5 and 8 (CP5 and CP8), account for 70 to 80% of Staphylococcus aureus strains isolated from human and animal sources. The capsular material has been shown to play a part in virulence and in resistance to phagocytosis. With a view to investigating the role that CP plays in pathogenicity or protection, relative measurement of cell-associated CP is desirable. Flow cytometry, which permits the analysis of individual bacteria, was...
Campanile, Floriana; Borbone, Sonia; Perez, Marianna; Bongiorno, Dafne; Cafiso, Viviana; Bertuccio, Taschia; Purrello, Simona; Nicolosi, Daria; Scuderi, Cristina; Stefani, Stefania
The prevalence and molecular characterisation of heteroresistant vancomycin-intermediate Staphylococcus aureus (hVISA) strains were determined in a large group of Italian strains isolated between 2005 and mid 2007. Amongst the 1284 strains isolated from documented infections in hospitalised patients (bloodstream infection, pneumonia, and skin and skin-structure infections), 139 S. aureus with vancomycin minimum inhibitory concentrations (MICs) between 1 mg/L and 2 mg/L were screened for the presence of hVISA using three different methods and were confirmed by population analysis profile (PAP). Thirty-six hVISA strains (25.9%) were detected. Amongst the three screening methods used, the macro Etest (MET) demonstrated 100% specificity and 75% sensitivity. hVISA strains were accessory gene regulator (agr) types I and II and belonged to the major nosocomial clones circulating in Italy (ST8, ST239, ST247 and ST228). All strains were susceptible to quinupristin/dalfopristin, linezolid, daptomycin, tigecycline and dalbavancin. In conclusion, we have demonstrated that hVISA isolates are common amongst MRSA isolates with MICs between 1 mg/L and 2 mg/L in Italy. MET, with its high sensitivity and specificity, should be used for early detection of hVISA, especially in patients with serious or prolonged infections sustained by MRSA. Finally, the most recent anti-Gram-positive drugs maintained their full spectrum of in vitro activity against these strains. PMID:20727722
M. Nagel; Dischinger, J.; Türck, M.; Verrier, D.; Oedenkoven, M.; Ngoubangoye, B.; Le Flohic, G.; Drexler, J. F.; Bierbaum, G.; Gonzalez, Jean-Paul
The risk of serious infections caused by Staphylococcus aureus is well-known. However, most studies regarding the distribution of (clinically relevant) S.aureus among humans and animals took place in the western hemisphere and only limited data are available from (Central) Africa. In this context, recent studies focused on S.aureus strains in humans and primates, but the question of whether humans and monkeys share related S.aureus strains or may interchange strains remained largely unsolved....
Objective: To detect genes for enterotoxins, exfoliative and toxic shock syndrome toxins in Staphylococcus aureus (S. aureus) strains isolated from clinical specimens. Study Design: Cross-sectional observational study. Place and Duration of Study: Department of Molecular Genetics, Dr. Ziauddin Hospital, Karachi, from January to December 2010. Methodology: Two hundred and ninety eight S. aureus clinical isolates were obtained from various clinical samples received at Dr. Ziauddin Hospital, Karachi. Out of these, 115 were detected as methicillin resistant (MRSA) by cefoxitin disk diffusion test showing a prevalence rate of 38.6%. Detection of individual toxin genes was performed by Polymerase Chain Reaction (PCR) by using only one primer pair for each tube. Uniplex primers were preferred as multiplex primers are longer in base pairs and have the potential for cross reaction due to non-specific binding and increase in optimization time. Results: The possession of a single gene or more than a single gene in MRSA isolates was found in 61.73% of clinical samples; the highest number was found in pus swab, followed by sputum, blood, urethral swab, and urine. The prevalence of toxin genes was higher in MRSA as compared to methicillin sensitive (MSSA) isolates (19.12%). Conclusion: PCR detects strains possessing toxin genes independent of their expression. The possession of genes for super-antigens seems to be a frequent and habitual trait of S. aureus more so in MRSA. (author)
Moisan, Hélène; Brouillette, Eric; Jacob, Christian Lebeau; Langlois-Bégin, Philippe; Michaud, Sophie; Malouin, François
Staphylococcus aureus small-colony variants (SCVs) are believed to account in part for the persistence of S. aureus during chronic infections. Little is understood about the gene expression profile that may explain the phenotype and distinguish SCVs from prototype S. aureus strains. In this study, DNA array transcriptional profiles of clinical SCVs isolated from the airways of cystic fibrosis patients were obtained and compared to those obtained from a laboratory-derived SCV strain (i.e., a r...
Full Text Available Dairy goat and sheep farms suffer severe economic losses due to intramammary infections, with S. aureus representing the main cause of clinical mastitis in small ruminants. In addition, S. aureus contamination of goat and sheep milk may cause staphylococcal food poisoning, as many traditional caprine and ovine milk products are not subjected to pasteurization. Data on virulence and antimicrobial resistance genes, as well as on the clonality of S. aureus detected in goat and sheep milk is scarce. Therefore, it was the aim of this study to determine i spa types and clonal complexes and ii virulence and resistance gene profiles of S. aureus isolated from goat and sheep milk. A total of 162 milk samples from sheep and goats presenting signs of an intramammary infection and 104 bulk milk samples were collected. While low prevalence rates of S. aureus were detected on single animal level, 46% of the bulk tank milk samples from small ruminants were positive for S. aureus. All isolates were spa typed and clonal complexes and virulence and resistance gene patterns were determined using a DNA microarray. Data from 49 S. aureus isolates was included in the statistical analysis and the construction of a SplitsTree. The analyzed isolates could be assigned to eleven clonal complexes, with the large majority of goat and sheep isolates being assigned to CC130 and CC133. The findings of this study suggest that S. aureus shows pronounced adaptation to small ruminants in general, but not to sheep or goats in particular. Although some common characteristics among S. aureus from caprine, ovine, and bovine milk samples were observed, S. aureus from small ruminants seem to form a distinct population. As 67% of the detected S. aureus strains exhibited at least one enterotoxin gene, many caprine or ovine raw milk products may be contaminated with low levels of enterotoxigenic S. aureus, stressing the importance of strict maintenance of the cold chain.
Merz, Axel; Stephan, Roger; Johler, Sophia
Dairy goat and sheep farms suffer severe economic losses due to intramammary infections, with Staphylococcus aureus representing the main cause of clinical mastitis in small ruminants. In addition, S. aureus contamination of goat and sheep milk may cause staphylococcal food poisoning, as many traditional caprine and ovine milk products are not subjected to pasteurization. Data on virulence and antimicrobial resistance genes, as well as on the clonality of S. aureus detected in goat and sheep milk is scarce. Therefore, it was the aim of this study to determine (i) spa types and clonal complexes (CC) and (ii) virulence and resistance gene profiles of S. aureus isolated from goat and sheep milk. A total of 162 milk samples from sheep and goats presenting signs of an intramammary infection and 104 bulk milk samples were collected. While low prevalence rates of S. aureus was detected on single animal level, 46% of the bulk tank milk samples from small ruminants were positive for S. aureus. All isolates were spa typed and CC and virulence and resistance gene patterns were determined using a DNA microarray. Data from 49 S. aureus isolates was included in the statistical analysis and the construction of a SplitsTree. The analyzed isolates could be assigned to eleven CC, with the large majority of goat and sheep isolates being assigned to CC130 and CC133. The findings of this study suggest that S. aureus shows pronounced adaptation to small ruminants in general, but not to sheep or goats in particular. Although some common characteristics among S. aureus from caprine, ovine, and bovine milk samples were observed, S. aureus from small ruminants seem to form a distinct population. As 67% of the detected S. aureus strains exhibited at least one enterotoxin gene, many caprine, or ovine raw milk products may be contaminated with low levels of enterotoxigenic S. aureus, stressing the importance of strict maintenance of the cold chain. PMID:27014240
Merz, Axel; Stephan, Roger; Johler, Sophia
Dairy goat and sheep farms suffer severe economic losses due to intramammary infections, with Staphylococcus aureus representing the main cause of clinical mastitis in small ruminants. In addition, S. aureus contamination of goat and sheep milk may cause staphylococcal food poisoning, as many traditional caprine and ovine milk products are not subjected to pasteurization. Data on virulence and antimicrobial resistance genes, as well as on the clonality of S. aureus detected in goat and sheep milk is scarce. Therefore, it was the aim of this study to determine (i) spa types and clonal complexes (CC) and (ii) virulence and resistance gene profiles of S. aureus isolated from goat and sheep milk. A total of 162 milk samples from sheep and goats presenting signs of an intramammary infection and 104 bulk milk samples were collected. While low prevalence rates of S. aureus was detected on single animal level, 46% of the bulk tank milk samples from small ruminants were positive for S. aureus. All isolates were spa typed and CC and virulence and resistance gene patterns were determined using a DNA microarray. Data from 49 S. aureus isolates was included in the statistical analysis and the construction of a SplitsTree. The analyzed isolates could be assigned to eleven CC, with the large majority of goat and sheep isolates being assigned to CC130 and CC133. The findings of this study suggest that S. aureus shows pronounced adaptation to small ruminants in general, but not to sheep or goats in particular. Although some common characteristics among S. aureus from caprine, ovine, and bovine milk samples were observed, S. aureus from small ruminants seem to form a distinct population. As 67% of the detected S. aureus strains exhibited at least one enterotoxin gene, many caprine, or ovine raw milk products may be contaminated with low levels of enterotoxigenic S. aureus, stressing the importance of strict maintenance of the cold chain. PMID:27014240
Kosmidis, Christos; Schindler, Bryan D; Jacinto, Pauline L; Patel, Diixa; Bains, Karanpreet; Seo, Susan M; Kaatz, Glenn W
Increased expression of multidrug resistance efflux pump (MDR-EP) genes in clinical isolates of Staphylococcus aureus occurs frequently, but its temporal and geographic variability is unknown. Such strains may contaminate the hospital environment, posing an infection control problem. Nearly 700 clinical isolates from different geographic locales as well as 91 environmental isolates recovered from two Detroit hospitals were studied. Ethidium bromide (EtBr) minimum inhibitory concentration (MIC), quantitative expression of all characterised chromosomal MDR-EP genes, and the presence of qacA/B and smr were determined for all strains. In addition, for norA- and/or mepA-overexpressing strains, the spa type was established. MDR-EP gene overexpression varied temporally and geographically, and overexpressing strains were present in the hospital environment. Increased expression of norA was associated with meticillin resistance and spa type t002, a rare type among control strains, consistent with widespread dissemination of a norA-overexpressing, meticillin-resistant S. aureus (MRSA) clone. Clonal spread also played a role for spa type t008, mepA-overexpressing, meticillin-susceptible strains. An EtBr MIC of ≤12.5 μg/mL was highly specific (>90%) in identifying strains lacking MDR-EP gene overexpression. PMID:22766161
Full Text Available This study was conducted to determine the prevalence rate, enterotoxigenecity, and antimicrobial resistance of S. aureus isolated from dairy products in Iran. From September 2010 to July 2011, a total of 347 samples from various dairy products, traditional and commercial, were collected from randomly selected retail stores. Overall, 20 samples (5.8% were found to be contaminated with S. aureus. The highest prevalence of S. aureus was found in traditional cheese (11.1%, followed by traditional ice-cream (5.9%, cream (5.6%, and butter (5.3%. The ability to synthesize classical staphylococcal enterotoxins (SEA-E was determined in 7 of 20 (35% isolates by using ELISA. SE type C was the most common enterotoxin found in the isolated S. aureus (42.9%, followed by SE type A (28.6%, SEA+SEC and SE type D (14.3%. Of the 20 isolates, 16 (80.0% were positive for one or more entrotoxin genes and 8 different genotypes were observed. Susceptibilities of the isolates were determined for 14 antimicrobial drugs using the disk diffusion assay. Most of the isolates (95.0% were resistant to one or more two antimicrobial agent and 45.0% of the isolates were resistant to three or more of drugs. Resistance to ampicillin was the most common finding (55.0%, followed by tetracycline (40.0% and penicillin G (30.0%. The results of this study showed the wide spread of enterotoxigenic and multidrug-resistant S. aureus strains in traditional dairy products in Iran and highlighted their public health hazards.
Ravinder Kumar; B R Yadav; R S Singh
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.
Full Text Available The objective of this study was to assess in vitro the antimicrobial activity of ethanolic extract of Polish propolis (EEPP against methicillin-sensitive Staphylococcus aureus (MSSA and methicillin-resistant Staphylococcus aureus (MRSA clinical isolates. The combined effect of EEPP and 10 selected antistaphylococcal drugs on S. aureus clinical cultures was also investigated. EEPP composition was analyzed by a High Performance Liquid Chromatography (HPLC method. The flavonoid compounds identified in Polish Propolis included flavones, flavonones, flavonolols, flavonols and phenolic acids. EEPP displayed varying effectiveness against twelve S. aureus strains, with minimal inhibitory concentration (MIC within the range from 0.39 to 0.78 mg/mL, determined by broth microdilution method. The average MIC was 0.54 ± 0.22 mg/mL, while calculated MIC50 and MIC90 were 0.39 mg/mL and 0.78 mg/mL, respectively. The minimum bactericidal concentration (MBC of the EEPP ranged from 0.78 to 3.13 mg/mL. The in vitro combined effect of EEPP and 10 antibacterial drugs was investigated using disk diffusion method-based assay. Addition of EEPP to cefoxitin (FOX, clindamycin (DA, tetracycline (TE, tobramycin (TOB, linezolid (LIN, trimethoprim+sulfamethoxazole (SXT, penicillin (P, erythromycin (E regimen, yielded stronger, cumulative antimicrobial effect, against all tested S. aureus strains than EEPP and chemotherapeutics alone. In the case of ciprofloxacin (CIP and chloramphenicol (C no synergism with EEPP was observed.
Strommenger, B.; Braulke, C.; Pasemann, B.; Schmidt, C.; Witte, W.
The continuous spread of community-acquired methicillin-resistant Staphylococcus aureus (caMRSA) and the introduction of these highly virulent isolates into hospitals represent increasing threats. The timely recognition of caMRSA strains is crucial for infection control purposes. Thus, we developed a PCR-based assay for the easy and rapid determination of those caMRSA clones that currently are the most prevalent in Germany and Central Europe. This assay was able to correctly identify the majo...
Godwin Onyemaechi Egwu
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.
Mamza, Sunday Akidarju; Egwu, Godwin Onyemaechi; Mshelia, Gideon Dauda
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. PMID:20560125
Full Text Available Abstract Background Staphylococcus aureus, one of the most frequently isolated pathogens in both hospitals and the community, has been particularly efficient at developing resistance to antimicrobial agents. In developed countries, as methicillin-resistant S. aureus (MRSA has prevailed and, furthermore, as S. aureus with reduced susceptibility to vancomycin has emerged, the therapeutic options for the treatment of S. aureus infections have become limited. In developing countries and especially African countries very little is known concerning the resistance of S. aureus to antibiotics. In Madagascar no data exist concerning this resistance. Objective To update the current status of antibiotic resistance of S. aureus in Antananarivo, Madagascar. Methods Clinical S. aureus isolates were collected from patients at the Institut Pasteur of Madagascar from January 2001 to December 2005. Susceptibility tests with 18 antibiotics were performed by the disk diffusion method. Results Among a total of 574 isolates, 506 were from community-acquired infections and 68 from nosocomial infections. There was no significant difference in the methicillin resistance rate between community-acquired strains (33 of 506; 6.5% and nosocomial strains (3 of 68, 4.4%. Many MRSA isolates were resistant to multiple classes of antibiotics. Resistance to tetracyclin, trimethoprim-sulfamethoxazole and erythromycin was more common. Among MRSA isolates resistance rates to rifampicin, fusidic acid, gentamicin and ciprofloxacin were lower than that observed with other drugs easily available in Madagascar. No isolates were resistant to glycopeptides. Conclusion The rate of methicillin-resistant S. aureus is not different between community-acquired and nosocomial infections and is still rather low in Madagascar.
Poliana de Castro Melo
Full Text Available Biofilms constitute a physical barrier, protecting the encased bacteria from detergents and sanitizers. The objective of this work was to analyze the effectiveness of sodium hypochlorite (NaOCl against strains of Staphylococcus aureus isolated from raw milk of cows with subclinical mastitis and Staphylococcus aureus isolated from the milking environment (blowers and milk conducting tubes. The results revealed that, in the presence of NaOCl (150ppm, the number of adhered cells of the twelve S. aureus strains was significantly reduced. When the same strains were evaluated in biofilm condition, different results were obtained. It was found that, after a contact period of five minutes with NaOCl (150ppm, four strains (two strains from milk , one from the blowers and one from a conductive rubber were still able to grow. Although with the increasing contact time between the bacteria and the NaOCl (150ppm, no growth was detected for any of the strains. Concerning the efficiency of NaOCl on total biofilm biomass formation by each S. aureus strain, a decrease was observed when these strains were in contact with 150 ppm NaOCl for a total period of 10 minutes. This study highlights the importance of a correct sanitation protocol of all the milk processing units which can indeed significantly reduce the presence of microorganisms, leading to a decrease of cow´s mastitis and milk contamination.
Eriksen, N H; Hartzen, S H; Bangsborg, Jette Marie;
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...
Ouyang, Ping; Chen, Junjie; Sun, Mao; Yin, Zhongqiong; Lin, Juchun; Fu, Hualin; Shu, Gang; He, Changliang; Lv, Cheng; Deng, Xuming; Wang, Kaiyu; Geng, Yi; Yin, Lizi
Both community-associated and hospital-acquired infections with methicillin-resistant Staphylococcus aureus (MRSA) have been increasingly reported around the world in the past 20 years. In 2006, the Centers for Disease Control and Prevention reported that 64 % of MRSA isolates were of the USA300 clonal type in infected patients in USA. The aim of our study was to estimate the in vitro effect of imperatorin on MRSA strain BAA-1717 (USA300). The effects of imperatorin on alpha-hemolysin (Hla) production, when strain BAA-1717 was co-cultured with sub-inhibitory concentrations of imperatorin, were analysed using susceptibility testing, hemolysis assays, western blotting and real-time PCR. Live/Dead analysis and cytotoxicity assays were employed to examine the protective effect of imperatorin against the strain BAA-1717-mediated injury of human alveolar epithelial cells (A549). The results showed that imperatorin has no anti-S. aureus activity at the tested concentrations in vitro. However, imperatorin can observably inhibit the production of Hla in culture supernatants and reduce the transcriptional levels of hla (the gene encoding Hla) and arg (the accessory gene regulator). Imperatorin prevented Hla-mediated A549 epithelial cell injury in a co-culture system. In conclusion, our results suggested that imperatorin has the potential to be developed as a new anti-virulence drug candidate for managing S. aureus infection. PMID:27043440
Full Text Available Background: Staphylococcus aureus (S. aureus has remained always an important pathogen of common infections acquired in community and as well as serious nosocomial infections. With advent of penicillins and cephalosporins, infections could be effectively treated, but with the global emergence of Methicillin Resistant Staphylococcus aureus strains (MRSA physicians were again left with limited treatment options. This scenario of increasing resistance is even more intense and challenging for developing countries like Pakistan. Hence with this background the study was carried out to establish the frequency of MRSA in clinical specimens and look into the available antibiotic treatment options.Methods: Samples of pus, blood, urine, body fluids and catheter tips submitted for culture in Microbiology department between August to September 2012, from outdoor and indoor adult patients of Pakistan Institute of Medical Sciences Islamabad, yielding growth of S. aureus were included in the study. After identification by standard methods, antibiotic susceptibility of the isolates was performed by Kirby Baeur disc diffusion method. The study was retrospective descriptive and observational.Results: Total 106 S. aureus were isolated. 45.3% of them were MRSA and majorities were from pus samples of hospitalized patients. All MRSA were 100% sensitive to vancomycin, whereas 87.5% to chloramphenicol. To rest of the non – beta lactam drugs, resistance of 80% or more was noted.Conclusion: S. aureus is a common clinical isolate from patients in this region ofPakistan and significant number were MRSA especially from hospitalized patients. Treatment options are limited to vancomycin and chloramphenicol.
Debasmita Dubey; Shakti Rath; Mahesh C Sahu; Subhrajita Rout; Nagen K Debata; Rabindra N Padhy
Objective:To investigate the infection of hospital-and community-acquired“erythromycin-induced clindamycin resistant”strains or D-test positives of clinical isolates of Staphylococcus aureus (S. aureus) (with and without methicillin resistance) in a hospital. Methods: Strains of S. aureus isolated from clinical specimens were subjected to D-test and antibiotic profiling. Results: Of the total 278 isolates, 140 (50.35%) were D-test positives and the rest were D-test negatives. Further, of 140 (100%) positives, 87 (62.14%) and 53 (37.85%) strains were from males and females, respectively. Of 140 (100%) positives, 117 (83.57%) were methicillin resistant S. aureus and 23 (16.42%) were methicillin sensitive S. aureus;of 140 strains, 103 (73.57%) strains from persons with and 37 (26.42%) were without related infections;of 140 strains, 91 (65%) and 49 (35%) were from hospital-and community-acquired samples, respectively. In 140 strains, 118 (84.28%) with comorbidities and 22 (15.71%) without comorbidities cases were recorded;similarly, persons with prior antibiotic uses contributed 108 (77.14%) and without 32 (22.85%) positive strains. These binary data of surveillance were analyzed by a univariate analysis. It was evident that the prior antibiotic uses and comorbidities due to other ailments were the determinative factors in D-test positivity, corroborated by low P values, P=0.001 1 and 0.002 4, respectively. All isolates (278) were resistant to 17 antibiotics of nine groups, in varying degrees;the minimum of 28%resistance for vancomycin and the maximum of 97%resistance for gentamicin were recorded. Further, of 278 strains, only 42 (15.1%) strains were resistant constitutively to both antibiotics, erythromycin resistant and clindamycin resistant, while 45 (16.2%) strains were constitutively sensitive to both antibiotics (erythromycin sensitive and clindamycin sensitive). Further, of the rest 191 (68.7%) strains were with erythromycin resistant and clindamycin
HOŞGÖR-LİMONCU, Mine; ERMERTCAN, Şafak; COŞAR, Güner
The present study aimed to determine the correlation between the bactericidal activity of vancomycin and quinupristin/dalfopristin (Q/D) on Staphylococcus aureus isolates and their minimal inhibition concentrations. The in-vitro susceptibilities of the 99 S. aureus isolates to vancomycin and Q/D were investigated by agar dilution. Thirty methicillin-resistant S. aureus (MRSA) and 30 methicillin-susceptible S. aureus (MSSA) vancomycin and Q/D susceptible isolates were involved in time-kill stu...
DU, JIMEI; Chen, Chun; Ding, Baixing; Tu, Jinjing; Qin, Zhiqiang; Parsons, Chris; Salgado, Cassandra; Cai, Qiangjun; SONG, Yulong; Bao, Qiyu; Zhang, Liming; Pan, Jingye; Wang, LiangXing; Yu, Fangyou
Staphylococcus aureus colonization and infection occur more commonly among persons living or working in crowded conditions, but characterization of S. aureus colonization within medical communities in China is lacking. A total of 144 (15.4%, 144/935) S. aureus isolates, including 28 (3.0%, 28/935) MRSA isolates, were recovered from the nares of 935 healthy human volunteers residing on a Chinese medical college campus. All S. aureus isolates were susceptible to vancomycin, quinupristin/dalfopr...
Full Text Available The aim of the presented study was to examine in vitro the antibacterial activity of protocatechuic acid ethyl ester (ethyl 3,4-dihydroxybenzoate, EDHB against Staphylococcus aureus clinical isolates alone and in the combination with four selected antibiotics. The EDHB antimicrobial activity was tested against twenty S. aureus strains isolated from the clinical samples, and three reference strains. The phenotypes and genotypes of resistance to methicillin for the tested strains were defined as well as the phenotypic resistance to macrolides, lincosamides and streptogramin B (MLSB. EDHB displayed diverse activity against examined S. aureus strains with the minimal inhibitory concentration (MIC within the range from 64 to 1024 µg/mL. Addition of ¼ MIC of EDHB into the Mueller-Hinton Agar (MHA resulted in augmented antibacterial effect in the presence of clindamycin. In the case of cefoxitin no synergistic effect with EDHB was noted. For erythromycin and vancomycin the decrease of mean MICs in the presence of EDHB was observed but did not reach statistical significance. The results of the present study showed that in vitro EDHB possesses antibacterial activity against S. aureus clinical strains and triggers a synergistic antimicrobial effect with clindamycin and to the lesser extent with erythromycin and vancomycin.
Full Text Available We report a catalase-negative Staphylococcus aureus isolated from a 56-year-old male diabetic patient with foot ulcer who attended our surgery ward. Species identification was confirmed by Gram staining, standard biochemical tests and PCR amplification of the nuc and fem genes. Antibiotic susceptibility showed that the strain was sensitive to imepenem, chloramphenicol, amoxicillin, vancomycin and resistant to oxacillin, penicillin, ceftriaxone, erythromycin, clindamycin, and amikacin. Clinicians and microbiologists must be encouraged to identify and report these atypical strains and the infections associated with them in order to establish their role in pathogenesis.
WANG Ye Ru; CHEN Qian; CUI Sheng Hui; LI Feng Qin
Objective To develop a matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) approach to identify Staphylococcus aureus (S. aureus) and differentiate methicillin-resistant S. aureus (MRSA) from methicillin-sensitive S. aureus (MSSA). Methods A total of 100 S. aureus strains isolated from clinical specimens and farm workers were collected and analyzed by MALDI-TOF-MS. And data obtained were interpreted with biotyper software. Results Ninety-two strains were identified by MALDI-TOF-MS as S. aureus at a level of secure genus and probable species, and 4 strains were identified at probable genus after their cultivation, spectral collection and data preprocessing. One strain was identified as S. aureus with lower score. It was revealed that identification of S. aureus by MALDI-TOF-MS was highly correlated with typing by biochemical and serological methods with an accuracy as high as 97%. The biotyper cluster analysis showed that 100 isolates were divided into 2 types at the distance level of 400. Higher peak intensity in the mass of both 3784 Da and 5700 Da was observed in MRSA, whereas that was absent from MSSA. Conclusion MALDI-TOF-MS is considered as a simple, rapid and highly reproducible technique with high-throughput and accuracy for the identification of S. aureus and it can reliably differentiate MRSA from MSSA.
Full Text Available Periodic monitoring of Staphylococcus aureus characteristics in a locality is imperative as their drug-resistant variants cause treatment problem. In this study, antibiograms, prevalence of toxin genes (sea-see, seg-ser, seu, tsst-1, eta, etb, and etd, PFGE types, accessory gene regulator (agr groups, and ability to form biofilm of 92 S. aureus Thailand clinical isolates were investigated. They were classified into 10 drug groups: groups 1–7 (56 isolates were methicillin resistant (MRSA and 8–10 (36 isolates were methicillin sensitive (MSSA. One isolate did not have any toxin gene, 4 isolates carried one toxin gene (seq, and 87 isolates had two or more toxin genes. No isolate had see, etb, or tsst-1; six isolates had eta or etd. Combined seg-sei-sem-sen-seo of the highly prevalent egc locus was 26.1%. The seb, sec, sel, seu, and eta associated significantly with MSSA; sek was more in MRSA. The sek-seq association was 52.17% while combined sed-sej was not found. Twenty-three PFGE types were revealed, no association of toxin genes with PFGE types. All four agr groups were present; agr group 1 was predominant (58.70% but agr group 2 strains carried more toxin genes and were more frequent toxin producers. Biofilm formation was found in 72.83% of the isolates but there was no association with antibiograms. This study provides insight information on molecular and phenotypic markers of Thailand S. aureus clinical isolates which should be useful for future active surveillance that aimed to control a spread of existing antimicrobial resistant bacteria and early recognition of a newly emerged variant.
Porcine brain coated vesicles were isolated from crude fractions of tissue homogenates by affinity separation using anticlathrin-coated STaphylococcus aureus (Staph A) cells as a solid-phase immunoadsorbent. The specificity of the immunoadsorption was monitored by SDS PAGE analysis and by competitive ELISA assays. SDS PAGE of the material immunoadsorbed from a fraction of porcine bran smooth microsomes showed a selective enrichment in a 180,000 mol wt protein. In an ELISA assay, this protein ...
Alexopoulos, A; Kimbaris, A C; Plessas, S; Mantzourani, I; Theodoridou, I; Stavropoulou, E; Polissiou, M G; Bezirtzoglou, E
Aromatic plants have been used widely to extend the shelf life of foods but at the same time research is undergoes for their properties as antibacterial agents in clinical use. Although there are promising results for the antimicrobial properties of various essential oils against environmental or food-isolated strains of Staphylococcus aureus, limited work has been done concerning these properties against clinical isolates of this pathogen. S. aureus is responsible for an increase number of nosocomial infections and at the same time exhibits increased resistance to synthetic agents. In this study, essential oils from eight aromatic plants common in Greece were isolated by hydrodistillation, analyzed by gas chromatography (GC) and GC/mass spectrometry (GC/MS) for their chemical components and tested for their antimicrobial activities against 24 clinical isolates of S. aureus. The methods used were disk diffusion and broth dilution in order to determine the Minimum Inhibitory Concentration (MIC). Our results showed that essential oils from Origanum vulgare and Origanum dictamnus were active against S. aureus when tested by disk diffusion, but exhibited increased MIC values (>256 mg/L) with the dilution method. In contrast, the reference strain NCTC 6571 showed to be extremely sensitive in most of the oils tested (MICs 0.25-32.0 mg/L) and resistant only to the essential oil from Ocimum basilicum. Therefore, there is no evidence of a potential clinical use for those essential oils and further research is needed in order to determine if they could substitute efficiently synthetic antibiotics or, perhaps be used in combination. PMID:21521657
Yoon, Jaewoo; Adachi, Kyoko; Kasai, Hiroaki
A facultatively anaerobic, Gram-stain negative, golden-yellow pigmented, non-motile and rod-shaped bacterium, designated strain A5Q-67(T) was isolated from leaf litter collected at the mangrove estuary of Nakama River, Japan. Phylogenetic analysis based on the 16S rRNA gene sequence revealed the novel isolate was affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes and that it showed highest sequence similarity (94.2 %) to Imtechella halotolerans K1(T). The strain could be differentiated phenotypically from recognized members of the family Flavobacteriaceae. The major fatty acids of strain A5Q-67(T) were identified as iso-C17:0 3-OH, summed feature 1 (iso-C15:1 H and/or C13:0 3-OH) and iso-C15:0 as defined by the MIDI system. The DNA G+C content was determined to be 36.7 mol%, the major respiratory quinone was identified as menaquinone 6 (MK-6) and a polar lipid profile was present consisting of phosphatidylethanolamine, two unidentified aminolipids and an unidentified lipid. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, the strain is considered to represent a novel genus for which the name Frondibacter aureus gen. nov., sp. nov. is proposed. The type strain of F. aureus is A5Q-67(T) (=KCTC 32991(T) = NBRC 110021(T)). PMID:25385000
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.
Full Text Available Background: Staphylococcus aureus is a gram positive coccus which is able to cause different kinds of infection in certain condition. The function of this bacteria is to provide the conditions for the invasion of it to the host with the secretion of different sorts of toxins such as Staphylococcus aureus enterotoxin, including important virulence factors that super antigens are all factors digestive inconvenience. Staphylococcus aureus enterotoxin-secreting toxins such conditions provides invasion of host genes. There are different types of SE, but type A enterotoxin (SEA and type B enterotoxin (SEB are the most important types. Therefore, in this study, the prevalence of Staphylococcus aureus toxin-producing enterotoxin genes (SEB, SEA in clinical strains isolated from patients in teaching hospitals of Shahrekord city, Iran, were studied. Methods: This cross-sectional and descriptive study, which was conducted from May 2014 to December 2014. A hundred and ten isolates of Staphylococcus aureus from patients collected over a period of 8 months and were first identified using standard biochemical methods and laboratory. Using standard methods and laboratory tests were identified and compared with the antibiotic oxacillin minimum inhibitory concentration were determined by broth micro dilution, and then they were assessed by polymerase chain reaction (PCR technique. Results: The results indicated that, 110 samples of dairy products infected by Staphylococcus aureus were detected. Two cases (1.8% of these infected samples were carrying both enterotoxin A and enterotoxin B genes. The frequencies of enterotoxin A genes were twenty-six cases (23/6% and The frequencies of enterotoxin B genes were two cases (1/8%, respectively. Conclusion: The detection of enterotoxin A and enterotoxin B genes, shows the most important role they have in bringing about superinfection. The detection of enterotoxin A and B genes, shows the most important role they have in
Lee, S H I; Cappato, L P; Corassin, C H; Cruz, A G; Oliveira, C A F
This research investigated the removal of adherent cells of 4 strains of Staphylococcus aureus and 1 Listeria monocytogenes strain (previously isolated from dairy plants) from polystyrene microtiter plates using peracetic acid (PAA, 0.5%) for 15, 30, 60, and 120 s, and the inactivation of biofilms formed by those strains on stainless steel coupons using the same treatment times. In the microtiter plates, PAA removed all S. aureus at 15 s compared with control (no PAA treatment). However, L. monocytogenes biofilm was not affected by any PAA treatment. On the stainless steel surface, epifluorescence microscopy using LIVE/DEAD staining (BacLight, Molecular Probes/Thermo Fisher Scientific, Eugene, OR) showed that all strains were damaged within 15 s, with almost 100% of cells inactivated after 30 s. Results of this trial indicate that, although PAA was able to inactivate both S. aureus and L. monocytogenes monospecies biofilms on stainless steel, it was only able to remove adherent cells of S. aureus from polystyrene microplates. The correct use of PAA is critical for eliminating biofilms formed by S. aureus strains found in dairy plants, although further studies are necessary to determine the optimal PAA treatment for removing biofilms of L. monocytogenes. PMID:26723125
Full Text Available ABSTRACT: BACKGROUND: Methicillin Resistant Staphylococcus aureus (MRSA has emerged as one of the most important nosocomial pathogen. Its remarkable ability to develop resistance to a variety of antibiotics makes it a major threat to public health. OBJECTIVES: - To detect the prevalence and in vitro antimicrobial susceptibility pattern of the MRSA isolates. MATERIALS & METHODS: - 202 Staphylococcus aureus strains isolated from c linical samples like blood, pus, sputum & body fluids were screened for Methicillin r esistance by standard disk diffusion method and then confirmed with Oxacillin Screening agar. Antibiotic susceptibility of both the MRSA and Methicillin sensitive Staphylococcus aureu s (MSSA for other antibiotics was subsequently carried out by standard disc diffusion method. RESULTS: Methicillin resistance was detected in 114 strains of Staphylococcus aureus giving a prevalence rate of 56.44%. More than 80% of the MRSA isolates were resistant to ant ibiotics such as Penicillins, Cephalosporins, Aminoglycosides, Macrolides and Quinolones. All str ains were uniformly sensitive to Vancomycin & Linezolid. Coexisting resistance to mo st of the antibiotics was significantly higher in the MRSA isolates as compared to the MSSA (Methic illin sensitive Staphylococcus aureus isolates (p < 0.001. INTERPRETATION & CONCLUSIONS: Multi drug resistance among the MRSA isolates poses a major hurdle in treating syste mic infections. Monitoring antibiotic sensitivity pattern, implementing aggressive surveill ance measures & good infection control practices would be helpful in reducing the prevalence of MRSA and its multi drug resistance
Antibiotic activity of the extract of Punica granatum Linn. over bovine strains of Staphylococcus aureus Atividade antimicrobiana do extrato de Punica granatum Linn. em linhagens de Staphylococcus aureus de origem bovina
Maria A. R. Silva; Jane S. Higino; Jozinete V. Pereira; José P. Siqueira-Júnior; Maria S.V. Pereira
Human and veterinary medicines have not been so well succeeded in order to achieving their goals concerning the treatment of infections for long term caused by Staphylococcus aureus linked to resistance development against antibiotic agents. The antibiotic activity of the Punica granatum Linn. fresh fruit pericarp extract was evaluated by the agar diffusion method on 38 S. aureus strains, isolated from apparently healthy lactating cows in farms situated in counties of the semi-arid region of ...
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.
Murat Karahan, Mehmet Nuri Acik1* and Burhan Cetinkaya
Full Text Available The aim of the present study was to characterize coagulase (coa positive Staphylococcus aureus strains (n=92 isolated from bovine subclinical mastitis in Turkey by PCR amplification of clumping factor A (clfA and protein A (spa genes. All the coa-positive S. aureus isolates were determined to harbor the genes encoding the IgG binding region (spa-IgG and the X region (spa-X of spa. On the other hand, 84 (91.3% isolates were positive for clfA gene. These three genes displayed size polymorphisms. It was concluded that spa gene polymorphisms for S. aureus, when used together with coa-PCR, can be proposed as good alternatives to conventional methods in typing S. aureus isolates of bovine origin which may provide valuable data for the development of effective control strategies against staphylococcal mastitis. The results of the present study showed that S. aureus isolates responsible for the mastitis cases in Turkey were genetically diverse.
Abdulazziz Zorgani; Omar Elahmer; Hisham Ziglam; Khalifa Sifaw Ghenghesh
Objectives: Tigecycline is a new glycylcycline group antibiotic with broad-spectrum activity. In the present study wereport on in vitro activity of tigecycline as well as the comparator antimicrobials linezolid and quinupristin/dalfopristinagainst methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin resistant Staphylococcus aureus (MRSA)strains isolated from burn wounds in Tripoli-Libya.Materials and methods: Included in the study 155 MSSA and 144 MRSA isolates from wounds of ...
Full Text Available Methicillin-resistant Staphylococcus aureus (S. aureus (MRSA, resistant to all antibiotics including Vancomycin, has been reported in Japan, USA, Canada and Brazil. Hence, the main objective of this study was to evaluate the possible presence of Vancomycin resistant or intermediate S.aureus in Karachi. A total of 850 clinical isolates were collected from two civil hospitals in the city between February 2006 and January 2007. They were identified using standard bacteriological methods. Sensitivity to recommended antibiotics was determined by disc diffusion, agar dilution, and E-test quantitative minimum inhibitory concentration (MIC. Susceptibility to natural or semi-natural products was determined by the agar dilution method. Out of 850 isolates, 250 were MRSA, of which 22% were resistant to 4 mg/ml Vancomycin, 24% to 8 mg/ml, 15.2% to 16 mg/ml, 10% to 20 mg/ml, and 13.2% to 30 mg/ml; the remaining 15.6% were sensitive to all used concentrations. Although we did not detect any Vancomycin-resistant S. aureus (VRSA, we found that 13% of the strains were intermediates (VISA, i.e. resistant to 30 mg/ml of Vancomycin. Because of the continuously increasing prevalence of VISA, it is imperative to minimize the use of Vancomycin. Indeed, the drug should only be prescribed for the treatment of documented, culture-proven infections with MRSA that are not susceptible to routine or alternative agents. This should help avoid the consequences of the development of Vancomycin resistant S. aureus (VRSA in our environment.
Liu, Ying; Zhang, Jiang; Zhong, Dengke; Ji, Lu; Yang, Junshu; Phillips, James; Ji, Yinduo
Staphylococcus aureus is one of the major respiratory pathogens associated with cystic fibrosis (CF) patients. In this study, we collected sputum and isolated fifty S. aureus isolates from CF patients with the median age of 9.5 years old. Then we determined the profiles of these isolates by antibiotic susceptibility testing, examining their cytotoxicity and ability to internalize into an epithelial cell line (A549), as well as multiple loci sequencing typing. Predominant CF S. aureus isolates were resistant to penicillin; however, these isolates were sensitive to various antibiotics, such as vancomycin and minocycline. Different CF S. aureus isolates showed distinct cytotoxic activities, and 90 % of CF S. aureus isolates possessed the enterotoxin genes, sea and hlg. Moreover, we found that multiple different CF S. aureus isolates appeared to have the distinct capacity of invading A549 cells. ST5 (14 %), ST30 (14 %), and ST8 (10 %) were prevalent ST types in these isolates. Further analysis revealed that ST5 and ST30 isolates were less toxic than ST8 and ST15 isolates, and that the ST5, ST15, ST59, and ST87 types of CF S. aureus were less capable of invading A549 cells. Our results suggest that the ST typing method may be useful in predicting cytotoxicity and the invading capacity of S. aureus isolates from patients with CF. PMID:27562596
Full Text Available Methicillin resistant Staphylococcus aureus (MRSA is an important cause of infections in hospitals and pose a great challenge to the treating clinicians; even emergence of vancomycin resistance has been reported. Therefore the knowledge of prevalence of MRSA and their antimicrobial profile becomes necessary. This study is aimed to determine prevalence of MRSA and their antimicrobial sensitivity pattern in Dakshina Kannada.Clinical specimens and carrier samples were cultured as per standard methods. The isolates were identified by using catalase test, coagulase tube test, mannitol fermentation and DNAase test. Antimicrobial susceptibility test was done for the isolates as per Kirby-Bauer disc diffusion method; the isolates were also tested for methicillin resistance using oxacillin and cefoxitin discs.A total of 250 isolates were tested (200 clinical isolates and 50 from carriers and 67 MRSA isolates were obtained (52 clinical samples and 15 from carriers. The degree of resistance to penicillin, ampicillin, ciprofloxacin, clindamycin and erythromycin were 100%, 100%, 53-56%, 14-16 % and 45-48% respectively. Resistance to vancomycin was not found. As the degree of resistance of MRSA towards antibiotics varies from region to region, in vitro susceptibility testing of every isolate of MRSA in clinical laboratories is inevitable.
Madzgalla, S; Syed, M A; Khan, M A; Rehman, S S; Müller, E; Reissig, A; Ehricht, R; Monecke, S
Comparatively few studies have been published describing Staphylococcus aureus/MRSA epidemiology in Central Asia including Pakistan. Here, we report the genotyping of Staphylococcus aureus strains (that include both methicillin-susceptible and methicillin-resistant Staphylococcus aureus) from community- and hospital-acquired skin and soft-tissue infections in a tertiary care hospital in the Malakand district of the Khyber Pakhtunkhwa Province of Pakistan. Forty-five isolates of Staphylococcus aureus were characterized by microarray hybridization. Twenty isolates (44 %) were MRSA, whereas 22 (49 %) were PVL-positive. Fourteen isolates (31 %) harboured both mecA and PVL genes. The dominant clones were CC121-MSSA (n = 15, 33 %) and the PVL-positive "Bengal Bay Clone" (ST772-MRSA-V; n = 13, 29 %). The PVL-positive CC8-MRSA-IV strain "USA300" was found once. The pandemic ST239-MRSA-III strain was absent, although it has previously been observed in Pakistan. These observations require a re-assessment of schemes for initial antibiotic therapy to cover MRSA and they emphasise the need for a rapid and non-molecular test for PVL. PMID:27262852
Silveira-Filho, Vladimir M; Luz, Isabelle S; Campos, Ana Paula F; Silva, Wellington M; Barros, Maria Paloma S; Medeiros, Elizabeth S; Freitas, Manuela F L; Mota, Rinaldo A; Sena, Maria J; Leal-Balbino, Tereza C
This work aimed to assess the clonal distribution among 94 strains of Staphylococcus aureus isolated from cow's milk, raw cheese, and a milking machine in 12 dairy farms in northeast Brazil, by analyzing different typing methods and detecting resistance and toxigenic profiles. For the first time, isolates of this region were assessed simultaneously by the polymorphism of the 3'-end coa gene and 16S-23S rDNA, pulsed-field gel electrophoresis, antibiotic resistance phenotyping, and toxigenic arsenal. Although pulsed-field gel electrophoresis patterns showed a wider variation (discriminatory index 0.83) than the PCR-based methods, the internal transcribed spacer-PCR proved to be a useful and inexpensive procedure for conducting epidemiological surveys of S. aureus on a regional scale. Each dairy farm had its own resistance profile, and in two herds, 63% of the strains were multiresistant, probably due to the indiscriminate use of antibiotics in bovine mastitis treatment. No methicillin-resistant S. aureus strains were detected in this study; however, 93.6% of S. aureus strains harbored variable profiles of staphylococcal enterotoxin genes seg, seh, sei, and sej. Transcriptional analysis revealed that 53.3% of staphylococcal enterotoxin genes actually transcribed, pointing out the food poisoning risk of these dairy products to consumers in the region. Based on the detection of the most prevalent clones in a herd or region, appropriate antibiotic therapy and specific immunization can be used for the treatment and control of staphylococcal mastitis. PMID:24680069
Full Text Available The study was intended for identification and characterization of Staphylococcus aureus isolated from raw cow milk. A total of 47 milk samples were collected from Sheshmore, Shutiakhali and Bangladesh Agricultural University Dairy Farm, Mymensingh. Using bacteriological, biochemical and PCR-based identification schemes, 12 (25.53% isolates were confirmed as S. aureus. All the isolates showed β-hemolysis on 5% sheep blood agar. S. aureus specific nuc gene (target size 279-bp was amplified in the cases of all isolates. The isolates were found as resistant to Penicillin (100%, Erythromycin (75% and Amoxicillin (100%. On the other hand, the isolates were sensitive to Ciprofloxacin (83.33%, Oxacillin (100%, Cloxacillin (100% and Neomycin (100%. The isolated S. aureus showed increased resistance to broad spectrum antibiotic (e.g., Ciprofloxacin. As many people have a tendency to drink raw milk and raw milk products, there is high risk of S. aureus infection in human.
Bicart-See, A; Rottman, M; Cartwright, M; Seiler, B; Gamini, N; Rodas, M; Penary, M; Giordano, G; Oswald, E; Super, M; Ingber, D E
Here we describe how Staphylococcus aureus bacteria can be rapidly isolated from clinical samples of articular fluid and synovial tissue using magnetic beads coated with the engineered chimeric human opsonin protein, Fc-mannose-binding lectin (FcMBL). The FcMBL-beads were used to capture and magnetically remove bacteria from purified cultures of 12 S. aureus strains, and from 8 articular fluid samples and 4 synovial tissue samples collected from patients with osteoarthritis or periprosthetic infections previously documented by positive S. aureus cultures. While the capture efficiency was high (85%) with purified S. aureus strains grown in vitro, direct FcMBL-bead capture from the clinical samples was initially disappointing (viscosity of these complex biological samples. Importantly, capture of pathogens using the FcMBL-beads was increased to 76% efficiency by pretreating clinical specimens with hypotonic washes, hyaluronidase and a protease cocktail. Using this approach, S. aureus bacteria could be isolated from infected osteoarthritic tissues within 2 hours after sample collection. This FcMBL-enabled magnetic method for rapid capture and concentration of pathogens from clinical samples could be integrated upstream of current processes used in clinical microbiology laboratories to identify pathogens and perform antibiotic sensitivity testing when bacterial culture is not possible or before colonies can be detected. PMID:27275840
Full Text Available Here we describe how Staphylococcus aureus bacteria can be rapidly isolated from clinical samples of articular fluid and synovial tissue using magnetic beads coated with the engineered chimeric human opsonin protein, Fc-mannose-binding lectin (FcMBL. The FcMBL-beads were used to capture and magnetically remove bacteria from purified cultures of 12 S. aureus strains, and from 8 articular fluid samples and 4 synovial tissue samples collected from patients with osteoarthritis or periprosthetic infections previously documented by positive S. aureus cultures. While the capture efficiency was high (85% with purified S. aureus strains grown in vitro, direct FcMBL-bead capture from the clinical samples was initially disappointing (< 5% efficiency. Further analysis revealed that inhibition of FcMBL binding was due to coating of the bacteria by immunoglobulins and immune cells that masked FcMBL binding sites, and to the high viscosity of these complex biological samples. Importantly, capture of pathogens using the FcMBL-beads was increased to 76% efficiency by pretreating clinical specimens with hypotonic washes, hyaluronidase and a protease cocktail. Using this approach, S. aureus bacteria could be isolated from infected osteoarthritic tissues within 2 hours after sample collection. This FcMBL-enabled magnetic method for rapid capture and concentration of pathogens from clinical samples could be integrated upstream of current processes used in clinical microbiology laboratories to identify pathogens and perform antibiotic sensitivity testing when bacterial culture is not possible or before colonies can be detected.
Vintov, Jan; Aarestrup, Frank Møller; Zinn, C. E.;
A total of 292 bovine Staphylococcus aureus isolates obtained from the 1950s (86 isolates), 1992 (107 isolates), and 2000 (99 isolates) were examined for antimicrobial susceptibility and phage typing. The same types of S. aureus (80, 52, 3A, 3A/3C, 42E, 77) were found among the isolates from all...... three time periods, representing 43.3% of the typeable isolates. This indicates that the Danish S. aureus population related to bovine mastitis has remained relatively unchanged over the last 50 years. The occurrence of antimicrobial resistance has remained low in Denmark in comparison to other...
Seventy one samples were randomly collected from patients suffering from different bacterial skin infections. Forty isolates could not grow on the artificial media after second subculture while 31 isolates were able to survive. Twenty six of them were identified as Staphylococcus aureus and 5 were identified as Pseudomonas aeruginosa. The isolated strains were tested for their susceptibilities to gentamycin, ampicillin, ciprofloxacin and amoxicillin antibiotics .Up to 88.4% of S. aureus and of 80% of P.aeruginosa isolates were found to be resistant to ampicillin. On the other. hand, about 30.7% of S. aureus and 20% of P. aeruginosa were resistant to ciprofloxacin reveals the lowest antibiotic resistance . The antibiotic sensitivity was retested for the most resistant bacterial isolates after irradiated by different doses of gamma radiation (0.5,1, 2 Gy). The previous doses increased S .aureus inhibition zone to gentamycin, from 7.5 mm for unirradiated cells to 25 mm for irradiated one. While ciprofloxacin inhibition zone increased from 1.5 cm to 3 cm in doses of 0.5 to 2.0 Gy. S. aureus sensitivity to amoxicillin increased from 0.0 to 1.0 cm inhibition zone with increase in dose from 0.5 to 2.0 Gy.While the previous doses had no effect on ampicillin resistance. The same doses increased P. aeruginosa isolate resistance. Very low doses of gamma irradiation increased S.aureus and P. aeruginosa capsule production, also increased the release rate of capsule content in both types of bacteria.
Seyed Asghar Havaei
Full Text Available Methicillin Resistant Staphylococcus aureus (MRSA strains are divided into Community Associated (CA- and Hospital Associated (HA- MRSA. These strains vary in antimicrobial resistance and pathogenicity. S. aureus is one of the most common microorganisms in ocular infections. This study was aimed to determine antimicrobial resistance patterns and genetic characteristics of MRSA strains isolated from ocular infections in Iran.Out of 171 S. aureus strains isolated from various clinical samples during September-December 2011 at Mashhad Emam Reza Hospital, 3 were cultured from eye discharge samples. Antimicrobial resistance tests were performed with MIC and disk diffusion methods and also genetic evaluation was done with Staphylococcal Cassette Chromosome mec (SCCmec, Accessory Gene Regulator (agr and Staphylococcal Protein A (spa typing, Multi Locus Sequence Typing (MLST and determination of toxin gene profile.All strains were MRSA and showed resistance to tetracycline, gentamicin and clindamycin too. Vancomycin, minocyclin and trimethoprim/sulfamethoxazole were effective on all ocular isolates. All isolates belonged to SCCmec IV type. MRSA1 belonged to ST239, CC8, Spa type t7688 and agrIII and had tst1 and hla toxin genes. MRSA2 belonged to ST239, CC8, Spa type t037 and agrI and had the hla toxin gene. Finally, MRSA3 belonged to ST291, CC398, Spa type t304, and agrI and had pvl and hla toxin genes.Phenotypic and genotypic evaluation of the isolated MRSA strains revealed that these strains belong to endemic Asian and livestock related clones that could reach from other body sites or environment to the eye of patients and developed ocular infection.
Coelho, Céline; Torres, Carmen; Radhouani, Hajer; Pinto, Luís; Lozano, Carmen; Gómez-Sanz, Elena; Zaragaza, Myriam; Igrejas, Gilberto; Poeta, Patrícia
Fifty-four healthy dogs were screened in Portugal for the presence of nasal methicillin-resistant Staphylococcus aureus (MRSA) carriage. Sixteen MRSA isolates (one/sample) were recovered from nasal samples of dogs, and they were typed by molecular methods (S. aureus protein A [spa]-, multilocus sequence typing-, staphylococcal cassette chromosome mec-typing). MRSA isolates were investigated for their susceptibility to antimicrobial agents by disk-diffusion test. The presence of resistance genes and of the Panton-Valentine leukocidin gene (lukF-lukS) was analyzed by PCR. Four different spa-types were identified among our MRSA isolates (t032, t432, t747, and t4726), with t032 as the most frequently detected. The sequence-type ST22 was identified in four tested MRSA isolates with different spa-types. All 16 isolates presented the staphylococcal cassette chromosome mec type IV. Most of MRSA isolates were resistant to ciprofloxacin, erythromycin, and clindamycin (94%-100%), and no resistance was identified to chloramphenicol, mupirocin, and trimethoprim-sulfametoxazole. The ermC and tetM resistance genes were detected in all MRSA isolates. The amino acid changes Ser84Leu in GyrA protein and Ser80Phe in GrlA protein were the most prevalent ones in our MRSA isolates. None of the MRSA strains carried the lukF-lukS genes. The results presented in this study indicate that healthy dogs may be a reservoir of MRSA that could be transmitted to humans by direct contact. PMID:21254810
Among the samples received in pathology laboratory, Pakistan institute of Medical Science, Islamabad, 5069 samples had bacterial growth, among these 2580 (51%) samples were Gram-positive cocci and 1688 were Staphylococcus aureus during a period of two years. Out of these Gram-positive cocci 56% were resistant to penicillin group, 27% were resistant to cephalosporin group, 22% were resistant to aminoglycoside group 15% were resistant to quinolone group and 31% were resistant to other antibiotics (cotrimaxazole, erythromycin, aztreonam, vancomycin, nitrofurantion and meropenam). Antibio-grams of Gram-positive cocci were determined against various antibiotics by disc diffusion method. The rate of resistance to most of the antibiotics such as ampicillin, piperacillin, carbenicillin, penicillin, cephradine, cefotaxime, erythromycin, ceclor, ofloxacin, pefloxacin, ciprofloxacin, cotrimexazole (septran), gentamicin, meropenem, ceftazidime, erythromycin, tobramycin, enoxacin was higher when tested against the isolates collected from pus as compared to those from blood and urine. Antibiotic resistant strains were more prevalent in pus samples than other clinical isolates (blood and urine). The randomly selected 155 strains of Staphylococcus aureus when tested against five groups of antibiotics showed resistance rate against ampicillin (92%), cephradine (92%), cephradine (60%), and gentamicin (58%). However intermediate resistance was found in case of vancomicin (38%), in hospitalized and non-hospitalized patients. (author)
Østergaard, Claus; Grønvall Kjær Hansen, Sanne; Møller, Jens K
Fast and reliable discrimination of methicillin-resistant Staphylococcus aureus (MRSA) isolates is essential in identifying an outbreak. Molecular typing methods, such as S. aureus protein A (spa) typing, multi locus sequence typing (MLST) and pulse field gel electrophoresis (PFGE) are generally...
Full Text Available Objective: The purpose of this study was to determine the prevalence of vancomycin-resistant Staphylococcus aureus isolated from clinical samples in Shiraz hospitals. Methods: From March to December 2012, 100 S. aureus isolates (mainly from wound and blood were collected from three hospitals in Shiraz, south of Iran. After identification of Staphylococcus aureus by biochemical, microbiological and molecular methods, antibiotic susceptibility testing was performed by Kirby-Bauer disc diffusion test for 13 different antibiotics. Vancomycin-resistant Staphylococcus aureus isolates were determined by vancomycin agar screening test and PCR for vancomycin resistant genes (vanA and vanB. Results: The lowest and highest resistance was seen for quinupristin-dalfopristin (n=1 and ampicillin (n=95, respectively. Vancomycin agar screening test showed that 37 isolates can grow on these media. Further study by PCR also detected vanA and/or vanB genes in all of these strains. Also, 19 isolates showed either vanA or vanB but were susceptible according to vancomycin agar screening test. In total, vanA and vanB resistant genes were detected in 34% and 37% of clinical isolates, respectively. Conclusion: The results showed that the frequency of vancomycin resistance genes (vanA, vanB is very high in Staphylococcus aureus strains isolated from patients in south of Iran. Thus, urgent interventions are needed to keep the emergence and transmission of these isolates to a minimum.
Popoola, Victor O; Carroll, Karen C.; Ross, Tracy; Reich, Nicholas G.; Perl, Trish M.; Aaron M Milstone
We studied the transmissibility of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and healthcare-associated methicillin-resistant S. aureus (HA-MRSA) strains and the association of MRSA colonization pressure and MRSA transmission in critically ill children. Importantly, we found that in hospitalized children MRSA colonization pressure above 10% increases the risk of MRSA transmission 3-fold, and CA-MRSA and HA-MRSA strains have similar transmission dynamics.
Evaluation of Vancomycin in Combination with Piperacillin-Tazobactam or Oxacillin against Clinical Methicillin-Resistant Staphylococcus aureus Isolates and Vancomycin-Intermediate S. aureus Isolates In Vitro
Dilworth, Thomas J.; Sliwinski, Jora; Ryan, Keenan; Dodd, Monique
Vancomycin with piperacillin-tazobactam is used as empirical therapy for critically ill patients. Studies of this combination against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-intermediate S. aureus (VISA) are limited, but β-lactams in combination with vancomycin have shown synergistic activity against MRSA and VISA. The goal of this study was to evaluate whether piperacillin-tazobactam and vancomycin were synergistic against MRSA and VISA in vitro. Bloodstream MRSA (n = 20) and VISA (n = 4) strains were selected. In vitro antimicrobial activities of piperacillin-tazobactam and oxacillin were evaluated by disk diffusion, and MICs were determined by Etest using Muller-Hinton agar with and without vancomycin at one-half the MIC. Time-kill studies evaluated 14 MRSA and all 4 VISA isolates using piperacillin-tazobactam at 300/35 mg/liter or oxacillin at 40 mg/liter alone and with vancomycin at one-half the MIC. Mean zones of inhibition for piperacillin-tazobactam and oxacillin increased with vancomycin against MRSA and VISA (P < 0.001 for all), and the MIC90 decreased with vancomycin against MRSA and VISA to values meeting susceptibility criteria for S. aureus (P < 0.001 for both antibiotics against MRSA). In MRSA time-kill studies, the mean 24-h reductions in inoculum for piperacillin-tazobactam, piperacillin-tazobactam with vancomycin, and oxacillin with vancomycin were 3.53, 3.69, and 2.62 log10 CFU/ml, respectively. The mean 24-h reductions in VISA inoculum for piperacillin-tazobactam, piperacillin-tazobactam with vancomycin, and oxacillin with vancomycin were 2.85, 2.93, and 3.45 log10 CFU/ml, respectively. Vancomycin with piperacillin-tazobactam or oxacillin demonstrated synergistic activity against MRSA and VISA. The clinical implications of these combinations against MRSA and VISA should be investigated. PMID:24277036
Zorgani, Abdulazziz; Elahmer, Omar; Ziglam, Hisham; Ghenghesh, Khalifa Sifaw
Objectives: Tigecycline is a new glycylcycline group antibiotic with broad-spectrum activity. In the present study we report on in vitro activity of tigecycline as well as the comparator antimicrobials linezolid and quinupristin/dalfopristin against methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin resistant Staphylococcus aureus (MRSA) strains isolated from burn wounds in Tripoli-Libya. Materials and methods: Included in the study 155 MSSA and 144 MRSA ...
Lee, Soomin; Ahn, Sooyeon; Lee, Heeyoung; Kim, Won-Il; Kim, Hwang-Yong; Ryu, Jae-Gee; Kim, Se-Ri; Choi, Kyoung-Hee; Yoon, Yohan
This study investigated the effect of adaptation of Staphylococcus aureus strains to the acidic condition of tomato in response to environmental stresses, such as heat and acid. S. aureus ATCC 13565, ATCC 14458, ATCC 23235, ATCC 27664, and NCCP10826 habituated in tomato extract at 35°C for 24 h were inoculated in tryptic soy broth. The culture suspensions were then subjected to heat challenge or acid challenge at 60°C and pH 3.0, respectively, for 60 min. In addition, transcriptional analysis using quantitative real-time PCR was performed to evaluate the expression level of acid-shock genes, such as clpB, zwf, nuoF, and gnd, from five S. aureus strains after the acid habituation of strains in tomato at 35°C for 15 min and 60 min in comparison with that of the nonhabituated strains. In comparison with the nonhabituated strains, the five tomato-habituated S. aureus strains did not show cross protection to heat, but tomato-habituated S. aureus ATCC 23235 showed acid resistance. In quantitative real-time-PCR analysis, the relative expression levels of acid-shock genes (clpB, zwf, nuoF, and gnd) were increased the most in S. aureus ATCC 23235 after 60 min of tomato habituation, but there was little difference in the expression levels among the five S. aureus strains after 15 min of tomato habituation. These results indicate that the variation of acid resistance of S. aureus is related to the expression of acid-shock genes during acid habituation. PMID:25285500
Nwankwo Emmanuel Onwubiko
Full Text Available BACKGROUND: The importance of Staphylococcus aureus as a persistent nosocomial and community acquired pathogen has become a global health concern. It has a remarkable capability of evolving different mechanisms of resistance to most antimicrobial agents. The aim of the present study is to establish the incidence of S. aureus in clinical specimens and its antibiotic sensitivity pattern to various antibiotics in this locality. METHODS: One hundred and fifty consecutive isolates of S. aureus obtained from various clinical specimens between January and December 2009 sent to the Medical Microbiology Laboratory Department of Aminu Kano Teaching Hospital (AKTH were confirmed by standard bacteriological procedures. Antibiotic sensitivity pattern was carried out by disc diffusion method. RESULTS: The age group with the highest number of isolates was (0-10yrs while wound infection had the highest frequency of S. aureus isolates (30.7% in the study. Males (62.0% were more infected than females (38.0%. The sensitivity pattern of S. aureus to the following antibiotics; Gentamicin, Amoxycillin/clavulanate, Streptomycin, Cloxacillin, Erythromycin, Chloramphenicol, Cotrimoxazole, Tetracycline, Penicillin, Ciprofloxacin, Ofloxacin, Levofloxacin, Ceftriaxone, Amoxycillin and vancomycin were 92.4%, 63.0%, 44.2%, 35.8%, 52.4%, 61.9%, 15.5%, 31.2%, 7.1%, 78.9%, 76.6%, 100%, 71.4%, 30.7% and 100% respectively. Methicillin resistant isolates were sensitive to Levofloxacin 93.7% and Ofloxacin 68.7%. CONCLUSION: The results of the present study show that the fluoroquinolones are effective in the management of Staphylococcus aureus infections including methicillin resistant strains in this environment.
Yan, Xiaomei; Wang, Bing; Tao, Xiaoxia; Hu, Qinghua; Cui, Zhigang; Zhang, Jianzhong; Lin, Yiman; You, Yuanhai; Shi, Xiaolu; Grundmann, Hajo
To characterize isolates of Staphylococcus aureus that were associated with staphylococcal food poisoning between 2006 and 2009 in Shenzhen, Southern China, a total of 52 Staphylococcus aureus isolates from 11 outbreaks were analyzed by using multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE). PCR analysis was used to analyze the staphylococcal enterotoxin (SE) genes sea to sei, and antimicrobial susceptibility testing was also performed. ST6 was the mo...
Ho, J.; O'Donoghue, M.; Guardabassi, Luca;
This study describes the isolation and characterization of methicillin-resistant Staphylococcus aureus (MRSA) from slaughtered pigs sampled from local markets in Hong Kong. The nares of 400 slaughtered pigs were cultured and MRSA isolates characterized for the presence of antibiotic-resistance...... predominant, with only 5/170 isolates displaying closely related types (t4474, t1939, t2922 and t5390). PFGE with sma1 and MLST confirmed the strains as ST9. Most isolates were multidrug resistant. Tetracycline resistance (97%) was mainly attributable to tet(K) with only 3% of isolates additionally harbouring...... tet(M). Resistance to erythromycin (89%) and chloramphenicol (71%) was associated with the presence of erm(C), and fex(A), respectively. No strains carried cfr and there was no resistance to linezolid, although minimum inhibitory concentration (MICs) were close to the resistance break point...
Full Text Available Aims: Emergence of resistant isolates of Staphylococcus aureus (S. aureus has resulted in failure of clindamycin therapy. The prevalence of inducible clindamycin resistance in S. aureus isolated from nursing students and pharmacy students (representing carriers exposed and not exposed to hospital environment respectively was evaluated. Materials and Methods: Nasal, throat, and palmar swabs were collected from 119 nursing students and 100 pharmacy students. S. aureus was identified and antibiogram obtained by Clinical and Laboratory Standards Institute guidelines. Inducible clindamycin resistance was detected by the D-test. Results: 36 and 34 individuals in the exposed and non-exposed groups respectively were carriers of S. aureus. 16.7% and 5.9% isolates showed inducible clindamycin resistance in exposed and non-exposed groups, respectively. The percentage of inducible clindamycin resistance was higher among methicillin-resistant S. aureus (MRSA (27.8% compared to methicillin-sensitive S. aureus (5.8%. Conclusion: S. aureus isolates resistant to β-lactams can also show inducible clindamycin resistance. Exposure to hospital environment was not found to be a risk factor for carriage of S. aureus with MLSBi phenotype.
Full Text Available Background: With emergence of multidrug-resistant strains of Staphylococcus aureus, there is an urgent need for the development of new antimicrobials which are narrow and pathogen specific. In this context, pyruvate kinase (PK an important enzyme in the glycolysis, which catalyses the formation of pyruvate which is the key intersection in the network of metabolic pathways was isolated and purified from Staphylococcus aureus ATCC12600. Methods: Purification steps included 10%-20% ammonium sulphate fractionation, diethyl aminoethyl cellulose ion exchange chromatography followed by gel filtration on Sephadex G-100. The pure PK molecular weight was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE and Km and Vmax for the PK was demonstrated. Results: The pure PK obtained from Sephadex G-100 gel filtration column exhibited Km of 0.78+0.18 µM and Vmax 76.47+0.82 µM NADH/mg/min and molecular weight of 250 kDa in solution. However, in SDS-PAGE showed single band with a molecular weight of 63 kDa confirming the homotetramer nature. In all steps of purification the Km remained constant indicating presence of only one kind of enzyme. The PK gene searched in the genomic sequences of Staphylococcus aureus also confirmed the same. Interpretation and conclusions: In Staphylococcus aureus presence of only one kind of PK unlike in other Gram positive bacteria exhibiting distinct differences in enzyme kinetics. This enzyme also showed the functionality of PK is found to be different from its human host. Therefore, PK probably is regarded as an ideal drug target in the development of new potent antimicrobials.
Intracellular Activity of Antibiotics in a Model of Human THP-1 Macrophages Infected by a Staphylococcus aureus Small-Colony Variant Strain Isolated from a Cystic Fibrosis Patient: Pharmacodynamic Evaluation and Comparison with Isogenic Normal-Phenotype and Revertant Strains▿ †
Nguyen, Hoang Anh; Denis, Olivier; Vergison, Anne; Theunis, Anne; Tulkens, Paul M.; Struelens, Marc J.; Van Bambeke, Françoise
Small-colony variant (SCV) strains of Staphylococcus aureus show reduced antibiotic susceptibility and intracellular persistence, potentially explaining therapeutic failures. The activities of oxacillin, fusidic acid, clindamycin, gentamicin, rifampin, vancomycin, linezolid, quinupristin-dalfopristin, daptomycin, tigecycline, moxifloxacin, telavancin, and oritavancin have been examined in THP-1 macrophages infected by a stable thymidine-dependent SCV strain in comparison with normal-phenotype...
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.
Zhang, Wanjiang; Hao, Zhihui; Wang, Yang; Cao, Xingyuan; Logue, Catherine M; Wang, Bing; Yang, Jing; Shen, Jianzhong; Wu, Congming
The aim of this study was to determine the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) isolates from pet animals and veterinary staff and the characteristics of these isolates. A total of 22 MRSA isolates were isolated from nasal swabs from dogs, cats and veterinary staff in six pet hospitals in six cities, and examined for antimicrobial susceptibility, the presence of resistance genes, Panton-Valentine leukocidin gene lukF-lukS, staphylococcal chromosomal cassette (SCC) mec typing, spa tying, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Of 22 MRSA isolates, 21 were recovered from pet animals, and one was isolated from a member of sstaff. All 22 MRSA strains were resistant to penicillin, oxacillin, azithromycin, clindamycin and ceftriaxone, and harboured mecA, ermB and linA genes. The lukF-lukS gene was not detected in any of the MRSA isolates. Eighteen MRSA strains from Qingdao belonged to ST59-MRSA-IV-spa t437. Of four MRSA isolates from Beijing, one belonged to ST398-MRSA-V-spa t034, and three belonged to ST239-MRSA-III-spa t030 profiles. Two PFGE types (A and B) were identified. Two isolates originating from dogs and one isolate originating from a staff member in Beijing shared similar PFGE patterns. Our cumulative data suggested that cross-transmission of MRSA may have occurred between pet animals and veterinary staff. PMID:21382731
Rahimi, Fateh; Shokoohizadeh, Leili
Methicillin resistant Staphylococcus aureus is one of the most common causes of a variety of infections ranging from wound infections to urinary tract infections (UTI) in hospital and community. In this study during 3 years we characterized the antibiotic resistance patterns of 491 hospital acquired MRSA and community associated MRSA strains by the guidelines of clinical and laboratory standard institute. A combination of high resolution PhP typing method and SCCmec typing were used for clonal dissemination of isolates. Among all 491 MRSA strains, diverse PhP types consisting of 29 common types (CTs) and 4 single types (STs) and also 2 different SCCmec types (III and IVa) were detected. In addition, 18 CTs were common among CA- and HA-MRSA strains and the presence of all 4 STs was limited to HA-MRSA strains. All isolates were resistant to penicillin and high level resistance was observed against ciprofloxacin, erythromycin, tobramycin and kanamycin and the rate of resistance to most of the antibiotic tested among HA-MRSA was significantly higher than CA-MRSA isolates. Moreover, all isolates showed susceptibility to linezolid, vancomycin and quinupristin-dalfopristin and very low resistance to fusidic acid, nitrofurantoin and chloramphenicol were detected. Our findings illustrated the increasing rate of clonal dissemination and persistence of highly antibiotic resistant CA-MRSA strains in Tehran hospitals, and also indicated the important role of the hospitals as the reservoir of MRSA strains. PMID:27265678
Piechowicz, Lidia; Garbacz, Katarzyna; Wisniewska, Katarzyna; Dajnowska-Stanczewa, Agata; Galiński, Janusz
The aim of study was to determine a production of proteinA in coagulase-negative Staphylococcus aureus (CNSA) or CF-negative S. aureus (CFNSA) strains. 59 CNSA and 18 CFNSA strains were isolated between 1997 and 2003 from different clinical specimens. The Protein A production was determined by immunoblotting method. The presence of protein A gene (spa) was investigated using the polymerase chain reaction (PCR). Two sets of phages and RFLP (Restriction Fragment Lenth Polymorphism) of coa gene method were used for typing strains. The results proved that the lack of ability of protein A production occurs more frequently in protein A-negative CFNSA strains with compare to the CNSA, which are protein A-positive for the majority of strains. Deficiencies of protein A, doesn't seem to be caused by the loss of spa gene. Protein A-negative CFNSA strains have phagotypes, RFLP and antibiotic resistant patterns which differ them from protein A-negative CNSA strains. Almost all of protein A-negative CFNSA and CNSA strains are resistant to methicillin. PMID:16494201
Smyth, Davida S; Kennedy, Jean; Twohig, Jane; Miajlović, Helen; Bolton, Declan; Smyth, Cyril J
A previous study carried out by the National Food Centre in Dublin on bacterial contamination of Irish domestic refrigeration systems revealed that 41% were contaminated with Staphylococcus aureus. One hundred fifty-seven S. aureus isolates were screened by multiplex PCR analysis for the presence of 15 staphylococcal enterotoxin and enterotoxin-like genes (sea-see, seg-sei, selj-selo, and selq) and the toxic shock toxin superantigen tst gene. Of the refrigerator isolates, 64.3% possessed more than one staphylococcal enterotoxin or staphylococcal enterotoxin-like gene. All bar one of the 101 staphylococcal enterotoxin or staphylococcal enterotoxin-like gene-positive strains possessed the egc locus bearing the seg, sei, selm, seln, and selo genes. Twelve random amplified polymorphic DNA (RAPD) types accounted for 119 (75.8%) of the strains, two of these types accounting for 25 (RAPD type 1, 15.9%) and 52 (RAPD type 5, 33.1%), respectively. All of the RAPD type 5 isolates possessed the egc gene cluster only. The RAPD type 5 amplicon profile was identical to that of S. aureus isolates associated with osteomyelitis in broiler chickens in Northern Ireland that also possessed the egc locus only. However, the RAPD type 5 domestic refrigerator and chicken isolates differed in penicillin G sensitivity, production of Protein A and staphylokinase, and crystal violet agar growth type. These findings highlight that the average Irish household refrigerator harbors potential enterotoxin-producing S. aureus that may or may not be of animal origin and, accordingly, is a potential reservoir for staphylococcal food poisoning. PMID:16541679
Hedin, Göran; Fang, Hong
Thirty-nine methicillin-resistant Staphylococcus aureus (MRSA) isolates with diverse genetic backgrounds and two reference strains were correctly identified as S. aureus on CHROMagar MRSA and S. aureus ID media. Growth inhibition on CHROMagar MRSA was noted. A combination of cefoxitin disk and S. aureus ID was found suitable for rapid MRSA screening.
Faezizadeh, Zohreh; Gharib, Amir; Godarzee, Masoud
Staphylococcus aureus is an opportunistic pathogen and remains a common cause of burn wound infections. Different studies have shown that entrapment of plant-derived compounds into liposomes could increase their anti-Staphylococcus aureus activity. Silymarin is the bioactive extract from the known plant Silybum marianum L. The objective of this study was to evaluate efficacy of silymarin in free and nanoliposomal forms against isolated methicillin-resistant Staphylococcus aureus (MRSA) strain. Silymarin-loaded nanoliposomes were prepared by extrusion method. The minimum inhibitory concentrations (MICs) of silymarin in free and nanoliposomal forms against MRSA were determined by broth dilution method. The killing rate of free and nanoliposomal forms of silymarin were analyzed. Ultimately, in-vivo therapeutic efficacy of nanoliposomes in burned mice infected by isolated MRSA was examined. The MICs of free and nanoliposomal forms of silymarin against isolated strain were 500 and 125 mg/L, respectively. The killing rate of silymarin-loaded nanoliposomes was higher than those of free silymarin. Topically treatment by silymarin in free and nanoliposomal forms resulted in almost 20 and 100% survival rates, respectively. The results suggest that silymarin-loaded nanoliposomes may provide a basis for future treatment of MRSA infections. PMID:25901172
Chen, Chunhui; Guo, Yan; Ma, Ying; Yang, Yang; Hu, Fupin; Xu, Xiaogang; Wang, Minggui
To investigate the prevalence, location and genetic environments of fosfomycin-resistance (fos) genes in methicillin-resistant Staphylococcus aureus (MRSA) clinical strains, 67 fosfomycin-resistant MRSA strains were isolated from the blood and cerebrospinal fluid samples at a teaching hospital in Shanghai. The presence of fos genes in these clinical strains was detected by PCR and sequencing. The locations of fos genes were determined by Southern blotting and genetic environments were analyzed by primer walking sequencing. Multiple locus sequence typing (MLST) was used to characterize genetic diversity. Conjugation was performed to evaluate the transferability of fos genes. Among 67 fosfomycin-resistant MRSA strains, nine high level fosfomycin resistant strains (≥128 μg/ml) were fosB-positive. Three new subtypes of fosB, designated as fosB4, fosB5, and fosB6, were identified. fosB1, fosB4 or fosB6 genes were located on small plasmids (ca. 2.5 kb) and flanked by an analogous replication gene (rep). Differently, the fosB5 gene was surrounded by a shorter rep gene and two copies of a transposon gene (tnp) that shared high identity with the IS257-like transposon. Four MLST types were found among the nine fosB-positive strains. Transconjugants with the fosB genes were resistant to fosfomycin with MIC 64 or 128 μg/ml. In conclusion, different subtypes and genetic environment of fosB genes indicate that gene heterogeneity for fosfomycin resistance in MRSA isolates. PMID:27144405
Full Text Available To investigate the prevalence, location and genetic environments of fosfomycin-resistance (fos genes in methicillin-resistant Staphylococcus aureus (MRSA clinical strains, 67 fosfomycin-resistant MRSA strains were isolated from the blood and cerebrospinal fluid samples at a teaching hospital in Shanghai. The presence of fos genes in these clinical strains was detected by PCR and sequencing. The locations of fos genes were determined by Southern blotting and genetic environments were analyzed by primer walking sequencing. Multiple locus sequence typing (MLST was used to characterize genetic diversity. Conjugation was performed to evaluate the transferability of fos genes. Among 67 fosfomycin-resistant MRSA strains, nine high level fosfomycin resistant strains (≥128 μg/ml were fosB-positive. Three new subtypes of fosB, designated as fosB4, fosB5, and fosB6, were identified. fosB1, fosB4 or fosB6 genes were located on small plasmids (ca. 2.5 kb and flanked by an analogous replication gene (rep. Differently, the fosB5 gene was surrounded by a shorter rep gene and two copies of a transposon gene (tnp that shared high identity with the IS257-like transposon. Four MLST types were found among the nine fosB-positive strains. Transconjugants with the fosB genes were resistant to fosfomycin with MIC 64 or 128 μg/ml. In conclusion, different subtypes and genetic environment of fosB genes indicate that gene heterogeneity for fosfomycin resistance in MRSA isolates.
Groves, Mitchell D; Crouch, Bethany; Coombs, Geoffrey W; Jordan, David; Pang, Stanley; Barton, Mary D; Giffard, Phil; Abraham, Sam; Trott, Darren J
This work investigated the molecular epidemiology and antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolated from veterinarians in Australia in 2009. The collection (n = 44) was subjected to extensive molecular typing (MLST, spa, SCCmec, dru, PFGE, virulence and antimicrobial resistance genotyping) and antimicrobial resistance phenotyping by disk diffusion. MRSA was isolated from Australian veterinarians representing various occupational emphases. The isolate collection was dominated by MRSA strains belonging to clonal complex (CC) 8 and multilocus sequence type (ST) 22. CC8 MRSA (ST8-IV [2B], spa t064; and ST612-IV [2B], spa variable,) were strongly associated with equine practice veterinarians (OR = 17.5, 95% CI = 3.3-92.5, P < 0.001) and were often resistant to gentamicin and rifampicin. ST22-IV [2B], spa variable, were strongly associated with companion animal practice veterinarians (OR = 52.5, 95% CI = 5.2-532.7, P < 0.001) and were resistant to ciprofloxacin. A single pig practice veterinarian carried ST398-V [5C2], spa t1451. Equine practice and companion animal practice veterinarians frequently carried multiresistant-CC8 and ST22 MRSA, respectively, whereas only a single swine specialist carried MRSA ST398. The presence of these strains in veterinarians may be associated with specific antimicrobial administration practices in each animal species. PMID:26735694
Full Text Available Abstract Background Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA, is an important cause of pyogenic skin and soft tissue infections (SSTIs. The aim of present study is to investigate the molecular characteristic of Staphylococcus aureus isolates isolated from the pus samples from the patients with purulent skin and soft tissue infections in Wenzhou, China. Methods Between December 2002 and June 2008, a total of 111 nonduplicate S. aureus isolates were collected from the pus samples of the patients with SSTIs in a teaching hospital in Wenzhou, China. All the tested isolates were confirmed as S. aureus using a Staph SPA agglutination kit, Gram's stain and a Vitek-60 microbiology analyzer. The homology among the tested isolates was determined by pulsed-field gel electrophoresis (PFGE. Multilocus sequence typing (MLST was used to determine the sequence types (STs of the selected isolates. The genotypes of SCCmec were determined by a multiplex PCR in the MRSA isolates. Panton-Valentine leukocidin (PVL genes and mecA were also determined by another multiplex PCR. Results Among the 111 S. aureus isolates, 48 and 63 isolates were community-acquired and hospital-acquired respectively. Sixty isolates were confirmed as MRSA harboring mecA detected by PCR. A total of 32 PFGE clonal types were obtained by PFGE, with 10 predominant patterns (types A to J. Twenty-five different STs including ST398 and three novel STs were found among 51 selected isolates. The main STs were ST239, ST1018, ST59, ST7 and ST88. Of 60 MRSA isolates, SCCmec II, III, IV and SCCmec V were found in three, 50, three and two isolates, respectively. The positive rates of PVL genes in overall isolates, HA-isolates, CA-isolates, MRSA isolates and MSSA isolates were 23.4% (26/111, 20.6% (13/63, 27.1% (13/48, 21.7% (13/60 and 25.5% (13/51, respectively. Eight (33.3%, 8/24 of 24 CA-MRSA isolates and 5 (13.9%, 5/36 of 36 HA-MRSA isolates were positive for PVL genes
Liaqat, Fakhra; Sheikh, Ali Ahmad; Nazir, Jawad; Hussain, Tanveer; Rabbani, Masood; Shaheen, Arfat Yousaf; Muhammad, Javed
Vancomycin resistant Staphylococcus aureus (VRSA) has been reported from many parts of the world including Asian countries. Hence, main objective of study was to evaluate the possible occurrence of VRSA in hospitals of Lahore city and to ensure the effectiveness of various substitute therapeutic options. A total of 150 samples of pus/wounds were collected from three hospitals of the city and VRSA were isolated and confirmed through recommended method of Clinical and Laboratory Standards Institute. Out of 51 (49.04%) methicillin resistant S. aureus (MRSA) isolates, 5 (9.8%) were found resistant to vancomycin. Minimum inhibitory concentration (MIC) of Linezolid (LZD), Moxifloxacin (MFX) and Clindamycin (CD) were calculated against VRSA isolates by broth microdilution test. All 5 (100%) isolates were susceptible to Linezolid and Clindamycin, while 4 (80%) were susceptible to Moxifloxacin. Ethanolic extracts of Turmeric, Mint, Coriander, Garlic, Kalonji, Cinnamon and Cloves illustrate average MIC values of 140.8 μg/mL, 563.2 μg/mL, 486.4 μg/mL, 614.4 μg/mL, 409.6 μg/mL, 281.6 μg/mL and 64 μg/mL, respectively against 5 VRSA strains. Concentration dependent increase in growth inhibition zones of ethanolic plant extract was recorded by agar well diffusion test. This study was helpful to find out the effective antibiotic against VRSA. Plant extracts encompass anti-staphylococcal activity and this finding demands necessity of further exploration of potential found in these natural herb. PMID:26004734
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
Poliana de Castro Melo
Full Text Available Biofilm formation is considered to be a selective advantage for Staphylococcus aureus mastitis isolates by facilitating bacterial persistence in the udder. It requires attachment to mammary epithelium, proliferation and accumulation of cells in multilayers. The objective of this study was to determine the sensitivity and specificity of three techniques for the detection of S. aureus biofilm-positive strains. Two phenotypic tests, including growth on microtitre plates and Congo red agar, were compared with a PCR technique using 94 S. aureus strains obtained from cows with subclinical mastitis from two farms in the state of São Paulo. These strains were characterised by in vitro slime production on Congo red agar, biofilm formation on microtitre plates and the presence of the icaA and icaD genes. The results revealed that 85% of the isolates tested produced slime on the Congo red agar, 98.9% of the isolates produced biofilms in vitro by adhering to sterile 96-well "U" bottom polystyrene tissue culture plates, and 95.7% of the isolates carried the icaA and icaD genes. The results of the phenotypic tests for biofilm formation were compared with those of the molecular analysis, and the sensitivity and specificity of the Congo red agar test were 88.9% and 100%, respectively, while those of the microtitre plate test were 100% and 25%, respectively. When the phenotypic methods for the detection of biofilm producers, namely growth on microtitre plates and Congo red agar, were compared, the sensitivity and specificity were 86% and 100%, respectively. Therefore, growth on Congo red agar and the microtitre plate test are methods that could be used to determine whether an isolate has the potential for biofilm production.
Katayama, Yuki; Sekine, Miwa; Hishinuma, Tomomi; Aiba, Yoshifumi; Hiramatsu, Keiichi
Complete reconstitution of the vancomycin-intermediate Staphylococcus aureus (VISA) phenotype of strain Mu50 was achieved by sequentially introducing mutations into six genes of vancomycin-susceptible S. aureus (VSSA) strain N315ΔIP. The six mutated genes were detected in VISA strain Mu50 but not in N315ΔIP. Introduction of the mutation Ser329Leu into vraS, encoding the sensor histidine kinase of the vraSR two-component regulatory (TCR) system, and another mutation, Glu146Lys, into msrR, belonging to the LytR-CpsA-Psr (LCP) family, increased the level of vancomycin resistance to that detected in heterogeneous vancomycin-intermediate S. aureus (hVISA) strain Mu3. Introduction of two more mutations, Asn197Ser into graR of the graSR TCR system and His481Tyr into rpoB, encoding the β subunit of RNA polymerase, converted the hVISA strain into a VISA strain with the same level of vancomycin resistance as Mu50. Surprisingly, however, the constructed quadruple mutant strain ΔIP4 did not have a thickened cell wall, a cardinal feature of the VISA phenotype. Subsequent study showed that cell wall thickening was an inducible phenotype in the mutant strain, whereas it was a constitutive one in Mu50. Finally, introduction of the Ala297Val mutation into fdh2, which encodes a putative formate dehydrogenase, or a 67-amino-acid sequence deletion into sle1 [sle1(Δ67aa)], encoding the hydrolase of N-acetylmuramyl-l-alanine amidase in the peptidoglycan, converted inducible cell wall thickening into constitutive cell wall thickening. sle1(Δ67aa) was found to cause a drastic decrease in autolysis activity. Thus, all six mutated genes required for acquisition of the VISA phenotype were directly or indirectly involved in the regulation of cell physiology. The VISA phenotype seemed to be achieved through multiple genetic events accompanying drastic changes in cell physiology. PMID:27067329
Chung, Hee-Jung; Jeon, Hong-Seon; Sung, Heungsup; Kim, Mi-Na; Hong, Soo-Jong
In this study, we investigated the rate of colonization of skin of children with atopic dermatitis (AD) by methicillin-resistant Staphylococcus aureus (MRSA) and characterized the isolates. Active skin lesions in pediatric AD patients were cultured with Rodac Staph (Komed, Korea). S. aureus isolates were examined for drug susceptibilities, analyzed for the eta, etb, tst, and pvl genes, and typed using agr polymorphism, pulsed-field gel electrophoresis of SmaI-restricted chromosomal DNA, and s...
N.B.Dhayanithi; T. T. Ajith Kumar; R. Ganesha Murthy; K. Kathiresan
Objective: leaf extract of A. marina was tested on the growth of clinically isolated multi-drug resistant Staphylococcus aureus and its bioactive compounds were attempted. Method: Clinical strain of Staphylococcus aureus, were isolated from sputum, pus and blood of different patients and 22 strains were screened for antibiotic susceptibility. Avicennia marina was extracted in different solvents and antibacterial assay was carried out using Kirby-Bauer’s disk diffusion method. Crude methanol extract of the mangrove was loaded on a silica gel column and eluted with chloroform and methanol (9:1 to 1:9) followed by ethyl acetate and methanol (9:1 to 1:9). Based on in vitro assay, the 12th fraction was subjected for minimum inhibitory concentration (MIC). The active fraction was analysed by using a Clarus 500 Perkin Elmer gas chromatography. Result: Based on the antibiotic susceptibility test, six strains (RMSA 6, RMSA12, RMSA16, RMSA18, RMSA19 and RMSA21) were resistance against methicillin, vancomycin and ciprofloxacin. The results indicated that the methanolic leaf extract showed the highest antibacterial activity against all the tested strains RMSA 6 (16mm), RMSA12 (15 mm), RMSA16 (13 mm), RMSA18 (10 mm), RMSA19 (17 mm) and RMSA21 (16 mm). The MIC of the partially purified extract showed potential results against all the multidrug resistant strains however, the lowest concentration was recorded against RMSA 6, RMSA19 and RMSA21 strain. In the GC-MS results, 5 bioactive compounds were identified from the partially purified extract of A.marina. Conclusion:The methanolic extract of A. marina has the more potential candidate to inhibit against multidrug resistant S. aureus.
Barboza-Corona, José Eleazar; de la Fuente-Salcido, Norma; Alva-Murillo, Nayeli; Ochoa-Zarzosa, Alejandra; López-Meza, Joel E
Antimicrobial therapy is a useful tool to control bovine mastitis caused by Staphylococcus aureus, as consequence an increase in staphylococci resistant cases has been registered. Alternative strategies are desirable and bacteriocins represent attractive control agents to prevent bovine mastitis. The aim of this work was to evaluate the activity of five bacteriocins synthesized by Bacillus thuringiensis against S. aureus isolates associated to bovine mastitis. Fifty S. aureus isolates were recovered from milk composite samples of 26 Holstein lactating cows from one herd during September 2007 to February 2008 in México and susceptibility of those isolates to 12 antibiotics and 5 bacteriocins from B. thuringiensis was evaluated. S. aureus isolates were mainly resistant to penicillin (92%), dicloxacillin (86%), ampicillin (74%) and erythromycin (74%); whereas susceptibility to gentamicin, trimethoprim and tetracycline was detected at, respectively, 92%, 88%, and 72%. All S. aureus isolates showed susceptibility to the five bacteriocins synthesized by B. thuringiensis, mainly to morricin 269 and kurstacin 287 followed by kenyacin 404, entomocin 420 and tolworthcin 524. Our results showed that S. aureus isolates had differences in the antimicrobial resistance patterns and were susceptible to bacteriocins produced by B. thuringiensis, which could be useful as an alternative method to control bovine mastitis. PMID:19359107
Full Text Available Research objective is to study antibacterial action of nanoparticles of iron and copper on polyantibiotically resistant clinical Staphylococcus aureus strains. Materials and methods include antibacterial action of nanoparticles of copper and iron on 10 Staphylococcus au¬reus strains, isolated from patients with purulent complications stayed in the in-patient department of traumatology and orthopedics. Solutions of powders of iron and copper have been prepared directly before the experiment in concentra¬tion from 0,001 to 1 mg/ml. it has been revealed that the influence of nanoparticles on growth of clinical strains and the intensity of antibacterial effect depends on the form of nanoparticles, their concentration and action time. concentration of 0,1 mg/ml and 1 mg/ ml of iron nanoparticles has provoked the decrease in quantity of microbe cells from 3 to 34 % (p <0,01. in smaller concentrations the reliable antibacterial effect has not been observed. Antibacterial activity of copper nanoparticles has been expressed in a wide range of concentrations from 0,001 mg/ml to 1 mg/ml, even during short-term action (30 minutes it has provoked reduction of quantity of the microbe cells grown on the firm nutrient medium, 97-100 % in comparison with the control (p <0,001. in conclusion it is to point out that copper nanoparticles have more expressed inhibitory effect on growth of clini��cal strains of golden staphylococcus than iron nanoparticle suspension. inhibition degree depends on superdispersed powder dosage and incubation period
Baffoni, Marina; Bessa, Lucinda J; Grande, Rossella; Di Giulio, Mara; Mongelli, Matteo; Ciarelli, Antonio; Cellini, Luigina
Chronic wounds, including diabetic foot ulcers, pressure ulcers and venous leg ulcers, represent a significant cause of morbidity in developed countries, predominantly in older patients. The aetiology of these wounds is probably multifactorial, but the role of bacteria in their pathogenesis is still unclear. Moreover, the presence of bacterial biofilms has been considered an important factor responsible for wounds chronicity. We aimed to investigate the laser action as a possible biofilm eradicating strategy, in order to attempt an additional treatment to antibiotic therapy to improve wound healing. In this work, the effect of near-infrared (NIR) laser was evaluated on mono and polymicrobial biofilms produced by two pathogenic bacterial strains, Staphylococcus aureus PECHA10 and Pseudomonas aeruginosa PECHA9, both isolated from a chronic venous leg ulcer. Laser effect was assessed by biomass measurement, colony forming unit count and cell viability assay. It was shown that the laser treatment has not affected the biofilms biomass neither the cell viability, although a small disruptive action was observed in the structure of all biofilms tested. A reduction on cell growth was observed in S. aureus and in polymicrobial biofilms. This work represents an initial in vitro approach to study the influence of NIR laser treatment on bacterial biofilms in order to explain its potentially advantageous effects in the healing process of chronic infected wounds. PMID:22182280
Karahan, Murat; Cetinkaya, Burhan
The genetic relatedness of coagulase (coa) positive Staphylococcus aureus isolated from cows with subclinical mastitis in Turkey was investigated by polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) analysis. Among 700 milk samples positive in the California Mastitis Test (CMT), species specific PCR identified 200 (28.6%) isolates as S. aureus and 161 (80.5%) of these isolates were positive for the 3' end of the coa gene by PCR. Most isolates (n=135, 83.9%) produced a single band on coa PCR, with molecular sizes ranging from 500 to 1400bp, whereas a small number of isolates (n=26, 16.1%) yielded two amplification products. Coa RFLP analysis using AluI and Hin6I revealed 23 and 22 band patterns, respectively. The detection of double bands by coa PCR, previously reported in human isolates, suggests that milking personnel can play a role in the transmission of S. aureus. PMID:16901735
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.
Watts, J L; Owens, W E
A latex agglutination test system (Rapid Mastitis Test [RMT]; Immucell, Portland, Maine) containing reagents for the identification of Staphylococcus aureus and Streptococcus agalactiae from bovine intramammary infections was evaluated with 527 staphylococcal and 267 streptococcal isolates. The RMT Staphylococcus aureus reagent detected 94.2% of 242 Staphylococcus aureus isolates, 80% of 25 Staphylococcus intermedius isolates, and 42.8% of 21 tube coagulase-positive Staphylococcus hyicus isol...
Valéria Cataneli Pereira
Full Text Available Objective: To determine, by phenotypic and genotypic methods, oxacillin susceptibility in Staphylococcus aureus strains isolated from pediatric and neonatal intensive care unit patients seen at the University Hospital of the Botucatu School of Medicine.Methods: A total of 100 S. aureus strains isolated from the following materials were studied: 25 blood cultures, 21 secretions, 12 catheters, 3 cannulae and one chest drain from 62 patients in the neonatal unit, and 36 blood cultures, one pleural fluid sample and one peritoneal fluid sample from 38 patients in the pediatric unit. Resistance of the S. aureus isolates to oxacillin was evaluated by the disk diffusion method with oxacillin (1 μg and cefoxitin (30 μg, agar screening test using Mueller-Hinton agar supplemented with 6 μg/ml oxacillin and 4% NaCl, and detection of the mecA gene by PCR. In addition, the isolates were tested for β-lactamase production using disks impregnated with Nitrocefin and hyperproduction of β-lactamase using amoxicillin (20 μg and clavulanic acid (10 μg disks.Results: Among the 100 S. aureus strains included in the study, 18.0% were resistant to oxacillin, with 16.1% MRSA being detected in the neonatal unit and 21.0% in the pediatric unit. The oxacillin (1 μg and cefoxitin (30 μg disk diffusion methods presented 94.4% and 100% sensitivity, respectively, and 98.8% specificity. The screening test showed 100% sensitivity and 98.8% specificity. All isolates produced β-lactamase and one of these strains was considered to be a hyperproducer.Conclusions: The 30 μg cefoxitin disk diffusion method presented the best result when compared to the 1 μg oxacillin disk. The sensitivity of the agar screening test was similar to that of the cefoxitin disk diffusion method and higher than that of the oxacillin disk diffusion method. We observed variations in the percentage of oxacillin-resistant isolates during the study period, with a decline over the last years which
Ballhausen, Britta; Kriegeskorte, André; Schleimer, Nina; Peters, Georg; Becker, Karsten
In staphylococci, methicillin resistance is mediated by mecA-encoded penicillin-binding protein 2a (PBP2a), which has a low affinity for beta-lactams. Recently, a novel PBP2a homolog was described as being encoded by mecC, which shares only 70% similarity to mecA. To prove that mecC is the genetic determinant that confers methicillin resistance in Staphylococcus aureus, a mecC knockout strain was generated. The S. aureus ΔmecC strain showed considerably reduced oxacillin and cefoxitin MICs (0.25 and 4 μg/ml, respectively) compared to those of the corresponding wild-type methicillin-resistant S. aureus (MRSA) strain (8 and 16 μg/ml, respectively). Complementing the mutant in trans with wild-type mecC restored the resistance to oxacillin and cefoxitin. By expressing mecC and mecA in different S. aureus clonal lineages, we found that mecC mediates resistance irrespective of the genetic strain background, yielding oxacillin and cefoxitin MIC values comparable to those with mecA. In addition, we showed that mecC expression is inducible by oxacillin, which supports the assumption that a functional beta-lactam-dependent regulatory system is active in MRSA strains possessing staphylococcal cassette chromosome mec (SCCmec) type XI. In summary, we showed that mecC is inducible by oxacillin and mediates beta-lactam resistance in SCCmec type XI-carrying strains as well as in different S. aureus genetic backgrounds. Furthermore, our results could explain the comparatively low MICs for clinical mecC-harboring S. aureus isolates. PMID:24752255
Full Text Available In 2008, an unusual strain of methicillin-sensitive Staphylococcus aureus (MSSA68111, producing both Panton-Valentine leukocidin (PVL and toxic shock syndrome toxin-1 (TSST-1, was isolated from a fatal case of necrotizing pneumonia. Because PVL/TSST-1 co-production in S. aureus is rare, we characterized the molecular organization of these toxin genes in strain 68111. MSSA68111 carries the PVL genes within a novel temperate prophage we call ФPVLv68111 that is most similar, though not identical, to phage ФPVL--a phage type that is relatively rare worldwide. The TSST-1 gene (tst in MSSA68111 is carried on a unique staphylococcal pathogenicity island (SaPI we call SaPI68111. Features of SaPI68111 suggest it likely arose through multiple major recombination events with other known SaPIs. Both ФPVLv68111 and SaPI68111 are fully mobilizable and therefore transmissible to other strains. Taken together, these findings suggest that hypervirulent S. aureus have the potential to emerge worldwide.
Full Text Available This study was an attempt at developing, establishing, validating and comparing the modified PAP method for detection of hetero-vancomycin resistant Staphylococcus aureus (h-VRSA with the routine antimicrobial susceptibility testing (using the BSAC standardized disc diffusion method, minimum inhibitory concentrations of vancomycin using standard E-test methodology and the Hiramatsu′s screening method. A total of 50 methicillin resistant Staphylococcus aureus obtained from various clinical specimens, along with the Mu 3 and Mu 50 strains as controls, were studied. No VRSA isolates were obtained. However, four of the test strains were positive by the Hiramatsu′s screening method, of which only one isolate could be confirmed by the modified PAP analysis method. This isolate was a coloniser from the drain fluid of a liver transplant recipient. The sensitivity, specificity, positive predictive value and the overall efficiency of the Hiramatsu′s screening method with the modified PAP analysis as the gold standard were found to be 100, 93.8, 25 and 94%, respectively. It is very essential for clinical laboratories to screen for h-VRSA, given the increasing use of glycopeptide antibiotics in therapy and the potential for failed therapy in patients infected with these strains.
Kwiecinski, Jakub; Kahlmeter, Gunnar; Jin, Tao
Many diseases caused by Staphylococcus aureus are associated with biofilm formation. However, the ability of S. aureus isolates from skin and soft tissue infections to form biofilms has not yet been investigated. We tested 160 isolates from patients with various skin infections for biofilm-forming capacity in different growth media. All the isolates formed biofilms, the extent of which depended on the type of growth medium. The thickest biofilms were formed when both plasma and glucose were present in the broth; in this case, S. aureus incorporated host fibrin into the biofilm's matrix. There were no differences in the biofilm formation between isolates from different types of skin infections, except for a particularly good biofilm formation by isolates from diabetic wounds and a weaker biofilm formation by isolates from impetigo. In conclusion, biofilm formation is a universal behavior of S. aureus isolates from skin infections. In some cases, such as in diabetic wounds, a particularly strong biofilm formation most likely contributes to the chronic and recurrent character of the infection. Additionally, as S. aureus apparently uses host fibrin as part of the biofilm structure, we suggest that plasma should be included more frequently in in vitro biofilm studies. PMID:25586078
Tenover, Fred C; Sinner, Scott W; Segal, Robert E; Huang, Vanthida; Alexandre, Shandline S; McGowan, John E; Weinstein, Melvin P
Following an initial response to vancomycin therapy, a patient with meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia developed endocarditis, failed a second course of vancomycin and then failed daptomycin therapy. An increase in the vancomycin minimum inhibitory concentrations of four consecutive MRSA blood isolates from 2 microg/mL to 8 microg/mL was shown by Etest. Population analysis of four successive blood culture isolates recovered over the 10-week period showed that the MRSA strain became progressively less susceptible to both vancomycin and daptomycin. Retrospectively, the macro Etest method using teicoplanin indicated a decrease in vancomycin susceptibility in the second blood isolate. The patient improved after treatment with various courses of trimethoprim/sulfamethoxazole, quinupristin/dalfopristin and linezolid. Early detection of vancomycin-heteroresistant S. aureus isolates, which appeared to have clinical significance in this case, continues to be a challenge for the clinical laboratory. Development of suitable practical methods for this should be given priority. Concurrent development of resistance to vancomycin and daptomycin, whilst rare, must be considered in a patient who is unresponsive to daptomycin following vancomycin therapy. PMID:19233622
K T Lim
Full Text Available The objective of this study was to determine the expression and transferability of tetracycline and erythromycin resistance among 188 MRSA strains from a Malaysian tertiary hospital. The minimum inhibitory concentrations (MICs for oxacillin, erythromycin, tetracycline and ciprofloxacin ranged from 4 to 512 μg/ml, 0.25 to 256 μg/ml, 0.5 to 256 μg/ml and 0.5 to 512 μg/ml, respectively. Tetracycline-resistant strains showed co-resistance towards ciprofloxacin and erythromycin. There was a significant increase (P<0.05 of high-level tetracycline (≥MIC 256 μg/ml and erythromycin (≥MIC 128 μg/ml resistant strains in between the years 2003 and 2008. All erythromycin-resistant strains harboured ermA or ermC gene and all tetracycline-resistant strains harboured tetM or tetK gene. The blaZ was detected in all MRSA strains, whereas ermA, tetM, ermC, tetK and msrA genes were detected in 157 (84%, 92 (49%, 40 (21%, 39 (21% and 4 (2% MRSA strains, respectively. The blaZ, tetM, ermC and tetK genes were plasmid-encoded, with ermC gene being easily transmissible. Tn5801-like transposon was present in 78 tetM-positive strains. ermA and tetM genes were the most prevalent erythromycin and tetracycline resistance determinants, respectively, in MRSA strains. The association of resistance genes with mobile genetic elements possibly enhances the spread of resistant traits in MRSA.
Suat Moi Puah; Kek Heng Chua; Jin Ai Mary Anne Tan
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 ...
R. Kasra Kermanshahi
Full Text Available Nowadays, the multiple drug resistance and resistance to different antimicrobial are observed in a wide variety of bacteria. One of these agents is U.V. ray that sometimes used to sterilize the operation room space and utensils and gamma ray to sterilize some medical Instruments such as disposal syringes & cottons and etc. If resistance emerges against the above mentioned factor, fighting microbs by these factors will encounter more problems.Therefore, In this research the multiple resistance of pathogenic strains of S. aureus isolated from different infections were studied. The M.I.C and M.B.C to penicillins were determined, using dilution tube method and plate cultured respectively. The influence of U.V ray on the growth of bacteria under hood of laminator flow was measured by photon-meter, during different times (0, 30, 60, 120, 240 Sec at intensity of radiation 0.25 J/m2.S-1. The study of gamma ray on the growth of these bacteria were done by Iridium 192 source projector sentinel 660 as a gamma ray generator. Gamma irradiation was used at the intensity of 20 Gy/min and with dose of 500, 750 and 1000 Gray. The statistical study of the results obtained in different experiments was processed using S.A.S software. The standard strains were used as control and comparison.In these results, the strains of S. aureus showed maximum and minimum of MIC = 0.125% - 65 µg/ml and MBC = 1-128 µg/ml, respectively. For the study of bacterial level of resistance to U.V. ray, The most important resistance strains to antibiotics have been selected. The mean number of the colonies grown in the culture medium area after 120 and 240 seconds of U.V. radiation were Log N/No = 21.8, 6.9 respectively in the strain of Staphylococcus.Resistance of isolated strains of S. aureus in this research was higher than those of standard strains.
Kroning, Isabela Schneid; Iglesias, Mariana Almeida; Sehn, Carla Pohl; Valente Gandra, Tatiane Kuka; Mata, Marcia Magalhães; da Silva, Wladimir Padilha
Staphylococcus aureus is the second most important pathogen involved in foodborne outbreaks in Brazil. Because of their widespread distribution and biofilm forming ability, handmade sweets are easily contaminated with S. aureus. The aim of this study was to isolate and identify coagulase-positive staphylococci (CPS) from handmade sweets produced in Pelotas City/Brazil. The virulence potential was checked by evaluating the presence of the staphylococcal enterotoxin genes, icaA and icaD genes, the biofilm forming potential and antimicrobial resistance of the isolates. It was find just S. aureus among the CPS isolates. All the S. aureus isolates had biofilm forming ability on stainless steel and more than half of them on polystyrene surfaces. The majority of the isolates carried the icaA (66.6%) and icaD (58.4%) genes and some of them had the genes encoding enterotoxins A (33.4%) and B (16.6%). Furthermore, the majority of the isolates (83%) were resistant to at least one of the tested antimicrobials and multidrug resistance was observed in 8.4% of the isolates. The isolates had virulence potential, and half of them were enterotoxigenic. In addition, the ability of all the isolates to produce biofilms highlights the danger posed by these potentially virulent microorganisms persisting in food manufacturing environments. PMID:27217365
Full Text Available The cassette chromosome mec (SCCmec present in methicillin-resistant Staphylococcus aureus (MRSA has two essential components, the ccr gene complex and the mec gene complex. Additionally, SCCmec has non-essential components called J regions which are used for MRSA subtyping. This study was performed to determine subtypes MRSA strains carrying SCCmec type I based on polymorphism of regions located downstream of the mecA gene. A total of 98 MRSA strains carrying SCCmec type I isolated from patients hospitalized at the County Hospital of Valdivia (Chile between May 2007 and May 2008, were analyzed by multiplex PCR designed to amplify the mecA gene and 7 DNA hypervariable regions located around the mecA gene. MRSA strains were classified into seventeen genotypes accordingly to amplification patterns of DNA hypervariable regions. Five genotypes showed amplification patterns previously described. The remaining twelve genotypes showed new amplification patterns. Genotypes 18 and Genotype 19 were the most frequently detected. Regions HVR, Ins117 and pI258 stand out as being present in more than 60% of tested isolates. The acquisition of hypervariable regions by MRSA is a continuous horizontal transfer process through which the SCCmec have been preserved intact, or even may give rise to new types and subtypes of SCCmec. Therefore it is possible to infer that most MRSA strains isolated at the County Hospital of Valdivia (Chile were originated from two local clones which correspond to Genotype 18 and Genotype 19.
Gongora, Carmen Espinosa; Moodley, Arshnee; Lipinska, Urszula;
INTRODUCTION: Staphylococcus aureus sequence type ST398 has recently gained attention due to the spread of methicillin-resistant strains among people exposed to livestock. The aim of this study was to explore temporal changes in the population structure of S. aureus in pigs over the last 40 years...... historical isolates from 1973-1974 (n = 19) and from 1991-2003 (n = 13), and 59 contemporary isolates from 2004-2009. The latter isolates represented the most common MLST types (ST1, ST9, ST97 and ST433) and spa types isolated from pigs in Europe. RESULTS AND DISCUSSION: S. aureus sequence type ST398...... isolates are occasionally reported in pigs today (ST8, ST30, ST97, ST387, ST1092, ST2468) or have never been described in this animal host (ST12, ST133, ST1343). These results indicate that the population structure of porcine S. aureus has changed over the last 40 years and confirm the current theory...
Du, Jimei; Chen, Chun; Ding, Baixing; Tu, Jinjing; Qin, Zhiqiang; Parsons, Chris; Salgado, Cassandra; Cai, Qiangjun; Song, Yulong; Bao, Qiyu; Zhang, Liming; Pan, Jingye; Wang, Liangxing; Yu, Fangyou
Staphylococcus aureus colonization and infection occur more commonly among persons living or working in crowded conditions, but characterization of S. aureus colonization within medical communities in China is lacking. A total of 144 (15.4%, 144/935) S. aureus isolates, including 28 (3.0%, 28/935) MRSA isolates, were recovered from the nares of 935 healthy human volunteers residing on a Chinese medical college campus. All S. aureus isolates were susceptible to vancomycin, quinupristin/dalfopristin and linezolid but the majority were resistant to penicillin (96.5%), ampicillin/sulbactam (83.3%) and trimethoprim/sulfamethoxazole (93.1%). 82%, (23/28) of the MRSA isolates and 66% (77/116) of the MSSA isolates were resistant to multiple antibiotics, and 3 MRSA isolates were resistant to mupirocin--an agent commonly used for nasal decolonization. 16 different sequence types (STs), as well as SCCmec genes II, III, IVd, and V, were represented among MRSA isolates. We also identified, for the first time, two novel STs (ST1778 and ST1779) and 5 novel spa types for MRSA. MRSA isolates were distributed in different sporadic clones, and ST59-MRSA-VId- t437 was found within 3 MRSA isolates. Moreover, one isolate with multidrug resistance belonging to ST398-MRSA-V- t571 associated with animal infections was identified, and 3 isolates distributed in three different clones harbored PVL genes. Collectively, these data indicate a high prevalence of nasal MRSA carriage and molecular heterogeneity of S. aureus isolates among persons residing on a Chinese medical college campus. Identification of epidemic MRSA clones associated with community infection supports the need for more effective infection control measures to reduce nasal carriage and prevent dissemination of MRSA to hospitalized patients and health care workers in this community. PMID:22114670
Full Text Available Staphylococcus aureus colonization and infection occur more commonly among persons living or working in crowded conditions, but characterization of S. aureus colonization within medical communities in China is lacking. A total of 144 (15.4%, 144/935 S. aureus isolates, including 28 (3.0%, 28/935 MRSA isolates, were recovered from the nares of 935 healthy human volunteers residing on a Chinese medical college campus. All S. aureus isolates were susceptible to vancomycin, quinupristin/dalfopristin and linezolid but the majority were resistant to penicillin (96.5%, ampicillin/sulbactam (83.3% and trimethoprim/sulfamethoxazole (93.1%. 82%, (23/28 of the MRSA isolates and 66% (77/116 of the MSSA isolates were resistant to multiple antibiotics, and 3 MRSA isolates were resistant to mupirocin--an agent commonly used for nasal decolonization. 16 different sequence types (STs, as well as SCCmec genes II, III, IVd, and V, were represented among MRSA isolates. We also identified, for the first time, two novel STs (ST1778 and ST1779 and 5 novel spa types for MRSA. MRSA isolates were distributed in different sporadic clones, and ST59-MRSA-VId- t437 was found within 3 MRSA isolates. Moreover, one isolate with multidrug resistance belonging to ST398-MRSA-V- t571 associated with animal infections was identified, and 3 isolates distributed in three different clones harbored PVL genes. Collectively, these data indicate a high prevalence of nasal MRSA carriage and molecular heterogeneity of S. aureus isolates among persons residing on a Chinese medical college campus. Identification of epidemic MRSA clones associated with community infection supports the need for more effective infection control measures to reduce nasal carriage and prevent dissemination of MRSA to hospitalized patients and health care workers in this community.
Voravuthikunchai, S P; Kitpipit, L
Aqueous and ethanolic extracts of ten traditional Thai medicinal plants were investigated for their ability to inhibit 35 hospital isolates of methicillin-resistant Staphylococcus aureus (MRSA). Nine medicinal plants displayed activity against all isolates tested. Ethanolic extracts of Garcinia mangostana, Punica granatum and Quercus infectoria were most effective, with MICs for MRSA isolates of 0.05-0.4, 0.2-0.4 and 0.2-0.4 mg/mL, respectively, and for S. aureus ATCC 25923 of 0.1, 0.2 and 0.1 mg/mL, respectively. MBCs for MRSA isolates were 0.1-0.4, 1.6-3.2 and 0.4-1.6 mg/mL, and for S. aureus ATCC 25923 were 0.4, 3.2 and 1.6 mg/mL, respectively. PMID:15882206
Zenão, S.; Aires, A.; Dias, Carla; Saavedra, M. J.; Fernandes, Conceição
Diabetic foot ulcers are often complicated by infection and among pathogens the Gram-positive Staphylococcus aureus is the most common isolated. Also concomitantly, the high prevalence of methicillin-resistant S. aureus (MRSA) was significant impact on successful treatment of infected foot ulcers. In this context, the purpose of the present study was to evaluate the antibacterial properties of Kefigel®, a natural product composed by nettle (Urtica dioica L), lavender (Lavandula angustifolia M...
de los Santos, R.; Fernández, M.; Carro, S.; P. Zunino
The aim of this work was to identify and to characterise Staphylococcus aureus isolates associated with subclinical mastitis obtained from milk of lactating cows showing a California Mastitis Test (CMT) score result of traces, 1, 2, or 3. Coagulase, hemolysis, presence of capsule, slime formation, biofilm production, autoaggregation, hemagglutination and antibiotic susceptibility were assessed to evaluate S. aureus virulence factors expression potentially associated to bovine subclinical mast...
Mukherjee, Sandipan; Ramesh, Aiyagari
In the present study, the adhesion of bacteriocin-producing probiotic strains of Lactobacillus plantarum onto extracellular matrix (ECM) proteins such as collagen and mucin and their potential to prevent pathogen invasion onto the ECM was ascertained. Fluorescence-based in vitro assays indicated that L. plantarum strains CRA21, CRA38 and CRA52 displayed considerable adhesion to ECM molecules, which was comparable to the probiotic Lactobacillus rhamnosus GG. Flow cytometry-based quantitative assessment of the adhesion potential suggested that L. plantarum CRA21 exhibited superior adhesion onto the ECM as compared with other lactic acid bacteria strains. Furthermore, fluorescence-based assays suggested that the highest inhibition of Staphylococcus aureus adhesion onto collagen and mucin by bacteriocin-producing L. plantarum strains was observed in the exclusion mode as compared with the competition and displacement modes. This observation was supported by the higher binding affinity (k(d)) for the ECM exhibited by the L. plantarum strains as compared with S. aureus. Interestingly, a crude plantaricin A extract from food isolates of L. plantarum displayed potent antibacterial activity on ECM-adhered S. aureus cells. It is envisaged that the L. plantarum isolates displaying bacteriocinogenic and ECM-adhering traits can perhaps be explored to develop safe antibacterial therapeutic agents. PMID:26445850
Ansari, Shamshul; Gautam, Rajendra; Shrestha, Sony; Ansari, Safiur Rahman; Subedi, Shankar Nanda; Chhetri, Muni Raj
Background Staphylococcus aureus (S. aureus), a normal flora of nasal cavity, can cause minor to life threatening invasive diseases and nosocomial infections. Methicillin resistant strains of S. aureus are causing a great challenge for treatment options. Therefore, the purpose of this study was to assess the nasal carriage rate of S. aureus, its methicillin resistant strains and risk factors in medical students prior to clinical exposure. Methods The bacterial growth of S. aureus from nasal s...
Full Text Available Background: In fact the biofilms are composed of bacterial cells living inmulticellular structures such as tissues and organs embedded within a self-produced matrix of extracellular polymeric substance (EPS. Ability to attach and biofilm formation are the most important virulence factors Staphylococcus aureus isolates. The aims of this study were to detect intracellular adhesion (ica locus and its relation to the biofilm formation phenotype in clinical isolates of S. aureus isolated from bloodcultures.Methods: A total of 31 clinical S. aureus isolates were collected from Loghman Hospital of Tehran, Iran. In vitro biofilm formation ability was determined by microliter tissue culture plates. All clinical isolates were examined for determination the ica locus by using PCR method.Results: Twelve (38.7% of the isolates were strong biofilm producers. The results showed that 18(80.6% of the isolates carried icaD gene, whereas the prevalence of icaA, icaB and icaC were 51.6%, 45.1% and 77.4% respectively.Conclusions: S. aureus clinical isolates have different ability to form biofilm. This may be caused by the differences in the expression of biofilm related genes, genetic make-up and physiological conditions.
Heijer, C.D.J. den; Bijnen, E.M.E. van; Paget, W.J.; Stobberingh, E.E.
Aim: To evaluate fusidic acid resistance pheno- and geno-typically in nasal carriage Staphylococcus aureus isolated from general practice patients in nine European countries. Materials & methods: Phenotypic fusidic acid resistance was determined by disc diffusion and MIC values, and genotypically by
Heijer, C.D. den; Bijnen, E.M. van; Paget, W.J.; Stobberingh, E.E.
AIM: To evaluate fusidic acid resistance pheno- and geno-typically in nasal carriage Staphylococcus aureus isolated from general practice patients in nine European countries. MATERIALS & METHODS: Phenotypic fusidic acid resistance was determined by disc diffusion and MIC values, and genotypically by
Mogahid M. Elhassan
Full Text Available Absolute dependence on mecA gene as the defining standard in determining the resistance of S. aureus to methicillin became the subject of distrust by many researchers. The present study aimed to determine the frequency of mecA gene in methicillin resistant S. aureus (MRSA isolates using polymerase chain reaction and to correlate its presence to conventional method. In this regard, two hundred S. aureus isolates were collected from patients with different diseases attending different hospitals in Shandi City, Sudan. Phenotypic Kirby-Bauer method confirmed the existence of methicillin resistant S. aureus in 61.5% of the subjected isolates with MICs ranging from 4 μg/mL to 256 μg/mL when using E-test. However, when amplifying a 310 bp fragment of the mecA gene by PCR, twelve out of the 123 MRSA isolates (9.8% were mecA negative, whereas all the 77 methicillin sensitive S. aureus (MSSA were mecA negative. In conclusion, this study drew attention to the credibility of the mecA gene and its usefulness in the detection of all MRSA strains without referring to the traditional methods. Hence, it is highly recommended to consider alternative mechanisms for β-lactam resistance that may compete with mecA gene in the emergence of MRSA phenomenon in the community.
Ünal, Nilgün; Askar, Şinasi; Macun, Hasan Ceyhun; Sakarya, Fatma; Altun, Belgin; Yıldırım, Murat
The aims of this study were to determine the existence of pvl gene, some toxin genes, and mecA gene in Staphylococcus aureus strains isolated from sheep milk and to examine antimicrobial resistance profiles in staphylococci from sheep and goats' milk. The milk samples were collected from 13 different small ruminant farms in Kirikkale province from February to August 2009. A total of 1,604 half-udder milk samples from 857 ewes and 66 half-udder milk samples from 33 goats were collected. Staphylococcus spp. were isolated and identified from the samples. Toxin genes and mecA gene among S. aureus strains were determined by PCR. Antimicrobial susceptibility of staphylococci was examined by the disk diffusion method on Mueller-Hinton agar, and interpreted according to the Clinical Laboratory Standards Institute (CLSI) guidelines. The prevalence of subclinical intramammary infection in both ewes and goats was 5.2%. The most prevalent subclinical mastitis agents were coagulase-negative staphylococci and S. aureus with prevalences 2.8% (n:46) and 1.3% (n = 21), respectively. The prevalence of resistances in isolated Staphylococcus spp. to penicilin G, tetracycline, erythromycin, gentamicin, and enrofloxacin were found as 26.9% (18), 7.5% (5), 6.0% (4), 3.0% (2), and 1.5% (1), respectively. Only 3 of the 21 S. aureus ewe isolates (13.4%) were shown to harbor enterotoxin genes being either seh, sej or sec. However, fourteen (66.6%) of the 21 S. aureus isolates had pvl gene while none of the isolates harbored mecA gene. In conclusion, Staphylococci were shown to be the most prevalent bacteria isolated from subclinical mastitis of ewes and goats and these isolates were susceptible to most of the antibiotics. In addition, S. aureus strains isolated from ewes were harboring few staphylococcal enterotoxin genes. However, Panton-Valentine leukocidin produced by S. aureus could be an important virulence factor and contribute to subclinical mastitis pathogenicity. PMID:21800213
Full Text Available Abstract Background There has been considerable effort to discover plant-derived antibacterials against methicillin-resistant strains of Staphylococcus aureus (MRSA which have developed resistance to most existing antibiotics, including the last line of defence, vancomycin. Pentacyclic triterpenoid, a biologically diverse plant-derived natural product, has been reported to show anti-staphylococcal activities. The objective of this study is to evaluate the interaction between three pentacyclic triterpenoid and standard antibiotics (methicillin and vancomycin against reference strains of Staphylococcus aureus. Methods and Results The activity of the standard antibiotics and compounds on reference methicillin-sensitive and resistant strains of S. aureus were determined using the macrodilution broth method. The minimum inhibitory concentration (MIC of the compounds was compared with that of the standard antibiotics. The interaction between any two antimicrobial agents was estimated by calculating the fractional inhibitory concentration (FIC index of the combination. The various combinations of antibiotics and compounds reduced the MIC to a range of 0.05 to 50%. Conclusion Pentacyclic triterpenoids have shown anti-staphylococcal activities and although individually weaker than common antibiotics produced from bacteria and fungi, synergistically these compounds may use different mechanism of action or pathways to exert their antimicrobial effects, as implicated in the lowered MICs. Therefore, the use of current antibiotics could be maintained in their combination with plant-derived antibacterial agents as a therapeutic option in the treatment of S. aureus infections.
Al-Ashmawy, Maha Abdou; Sallam, Khalid Ibrahim; Abd-Elghany, Samir Mohammed; Elhadidy, Mohamed; Tamura, Tomohiro
The present work was undertaken to study the prevalence, molecular characterization, virulence factors, and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) in raw milk and dairy products in Mansoura City, Egypt. MRSA was detected in 53% (106/200) among all milk and dairy products with prevalence rates of 75%, 65%, 40%, 50%, and 35% in raw milk, Damietta cheese, Kareish cheese, ice cream, and yogurt samples, respectively. The mean S. aureus counts were 3.49, 3.71, 2.93, 3.40, and 3.23 log10 colony-forming units (CFU)/g among tested raw milk, Damietta cheese, Kareish cheese, ice cream and yogurt, respectively, with an overall count of 3.41 log10 CFU/g. Interestingly, all recovered S. aureus isolates were genetically verified as MRSA strains by molecular detection of the mecA gene. Furthermore, genes encoding α-hemolysin (hla) and staphylococcal enterotoxins (sea, seb, sec) were detected in all isolates. The antimicrobial susceptibility pattern of recovered MRSA isolates against 13 tested antimicrobials revealed that the least effective drugs were penicillin G, cloxacillin, tetracycline, and amoxicillin with bacterial resistance percentages of 87.9%, 75.9%, 65.2%, and 55.6%, respectively. These findings suggested that milk and dairy products represent a potential infection risk threat of multidrug-resistant and toxigenic S. aureus in Egypt due to neglected hygienic practices during production, retail, or storage stages. These findings highlighted the crucial importance of applying more restrictive hygienic measures in dairy production in Egypt for food safety. PMID:26836943
Francois, Patrice; Huyghe, Antoine; Charbonnier, Yvan; Bento, Manuela; Herzig, Sébastien; Topolski, Ivan; Fleury, Bénédicte; Lew, Daniel; Vaudaux, Pierre; Harbarth, Stephan; van Leeuwen, Willem; van Belkum, Alex; Blanc, Dominique S.; Pittet, Didier; Schrenzel, Jacques
Fast and reliable genotyping methods that allow real-time epidemiological surveillance would be instrumental to monitoring of the spread of methicillin-resistant Staphylococcus aureus. We describe an automated variable-number tandem repeat-based method for the rapid genotyping of Staphylococcus aureus. Multiplex PCR amplifications with eight primer pairs that target gene regions with variable numbers of tandem repeats were resolved by microcapillary electrophoresis and automatically assessed by cluster analysis. This genotyping technique was evaluated for its discriminatory power and reproducibility with clinical isolates of various origins, including a panel of control strains previously characterized by several typing methods and collections from either long-term carriers or defined nosocomial outbreaks. All steps of this new procedure were developed to ensure a rapid turnaround time and moderate cost. The results obtained suggest that this rapid approach is a valuable tool for the genotyping of S. aureus isolates in real time. PMID:16000459
Saito, Etsuko; Yoshida, Nanako; Kawano, Junichi; Shimizu, Akira; Igimi, Shizunobu
Five hundred and fifty fish samples from various stages in the course of distribution in Hyogo Prefecture (209 retailed in super markets, 173 obtained from fishery cooperatives at a harbor, 91 caught by trawling and 77 caught by rod fishing) were examined for contamination with Staphylococcus aureus (S. aureus). S. aureus was detected in 41 (19.6%) of the retail fish samples and 46 (26.6%) of the samples from the fishery cooperatives. No S. aureus was isolated from the live fish (91 trawled and 77 fished by rod). With regard to the retail fish, the contamination rate of processed fish (26.0%) was significantly higher than that of unprocessed fish (14.2%). For 88 samples, the efficacy of the selective medium was compared using Baird-Parker agar and mannitol salt agar supplemented with egg yolk (MSEY agar) by the direct plate and enrichment culture methods. Using the direct culture method, the S. aureus positive rate with the Baird-Parker agar (30.7%) was significantly higher (Pagar (6.8%). The enrichment culture method remarkably raised the S. aureus detection rate. Seventy-eight (85.7%) of 91 isolates belonged to the human ecovar. Sixty-two (68.1%) of the 91 isolates had some enterotoxin genes, including 44 (48.4%) with the sea gene. These data showed that the fish were contaminated with S. aureus after landing and that Baird-Parker agar had an advantage in detecting S. aureus with a direct plate culture. PMID:20953131
Assadian, Ojan; Wehse, Katrin; Hübner, Nils-Olaf; Koburger, Torsten; Bagel, Simone; Jethon, Frank; Kramer, Axel
Background: An in-vitro study was conducted investigating the antimicrobial efficacy of polihexanide and triclosan against clinical isolates and reference laboratory strains of Staphylococcus aureus and E scherich ia coli. Methods: The minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC) were determined following DIN 58940-81 using a micro-dilution assay and a quantitative suspension test following EN 1040. Polihexanide was tested in polyethylene glycol 4000...
Pumarola, J; Berástegui, E; Canalda, C; Brau, E
The mean goal of this study is the determination of the conduct of 120 strains of Staphylococcus aureus against seven root canal sealers: Traitement Spad, Endométhasone, N2 Universal, AH26 with silver, Diaket-A, Tubli Seal and Sealapex. The agar diffusion test was employed in the determination of its bacterial growth inhibition. The results obtained have demonstrated values very different between the tested strains. Therefore we recommended to employ strains with reference in the investigation of the bacterial growth inhibition in order to repeat equal experimentation conditions. PMID:1659856
Full Text Available Essential oils extracted by microwave assisted hydrodistillation technique from Ocinum basilicum and Mentha piperita were characterized by GC-MS. An adapted diffusion method was used in order to assess the potentiator effect of the essential oils on the susceptibility of Staphylococcus aureus clinical and reference strains to some of the currently used antibiotics, i.e. clindamycin, ciprofloxacin, tetracycline, gentamicin, penicillin and erythromycin.. The Ocimum basilicum and Mentha piperita essential oils, exhibited a strong, strain specific influence on the antibiotic susceptibility of the tested strains.
Ghasemzadeh-Moghaddam, H; Neela, V; van Wamel, W; Hamat, R A; Shamsudin, M Nor; Hussin, N Suhaila Che; Aziz, M N; Haspani, M S Mohammad; Johar, A; Thevarajah, S; Vos, M; van Belkum, A
We performed a prospective observational study in a clinical setting to test the hypothesis that prior colonization by a Staphylococcus aureus strain would protect, by colonization interference or other processes, against de novo colonization and, hence, possible endo-infections by newly acquired S. aureus strains. Three hundred and six patients hospitalized for >7 days were enrolled. For every patient, four nasal swabs (days 1, 3, 5, and 7) were taken, and patients were identified as carriers when a positive nasal culture for S. aureus was obtained on day 1 of hospitalization. For all patients who acquired methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus via colonization and/or infection during hospitalization, strains were collected. We note that our study may suffer from false-negative cultures, local problems with infection control and hospital hygiene, or staphylococcal carriage at alternative anatomical sites. Among all patients, 22% were prior carriers of S. aureus, including 1.9% whom carried MRSA upon admission. The overall nasal staphylococcal carriage rate among dermatology patients was significantly higher than that among neurosurgery patients (n = 25 (55.5%) vs. n = 42 (16.1%), p 0.005). This conclusion held when the carriage definition included individuals who were nasal culture positive on day 1 and day 3 of hospitalization (p 0.0001). All MRSA carriers were dermatology patients. There was significantly less S. aureus acquisition among non-carriers than among carriers during hospitalization (p 0.005). The mean number of days spent in the hospital before experiencing MRSA acquisition in nasal carriers was 5.1, which was significantly lower than the score among non-carriers (22 days, p 0.012). In conclusion, we found that nasal carriage of S. aureus predisposes to rather than protects against staphylococcal acquisition in the nose, thereby refuting our null hypothesis. PMID:26183299
Koh, Young Rae; Kim, Kye-Hyung; Chang, Chulhun L.
Background We estimated the prevalence and clinical impact of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA). The concordance between macromethod and glycopeptide resistance detection (GRD) E tests was determined. In addition, predictors of clinical outcomes in hospitalized patients with S. aureus bacteremia (SAB) or pneumonia (SAP) were evaluated. Methods We obtained 229 consecutive S. aureus isolates from all hospitalized patients at two university hospitals located in Busan and Yangsan, Korea. Standard, macromethod, and GRD E tests were performed. Additionally, we reviewed the medical records of all patients. Among the 229 patients, predictors of clinical outcomes were analyzed for 107 patients with SAB and 39 with SAP. Results Among the 229 isolates, 34.5% of S. aureus isolates and 50.7% of methicillin-resistant S. aureus isolates exhibited the hVISA phenotype based on the macromethod E test. hVISA was nearly associated with treatment failure in patients with SAB (P=0.054) and was significantly associated with treatment failure in patients with SAP (P=0.014). However, hVISA was not associated with 30-day mortality in patients with SAB or SAP. The concordance between the macromethod and GRD E tests was 84.2%. Conclusions hVISA is quite common in the southeastern part of Korea. hVISA is associated with treatment failure in patients with SAP. PMID:26915612
Full Text Available Staphylococcus aureus is an important infection in hemodialysis patients. We studied the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA and its antibiotic resistance pattern in patients receiving hemodialysis as well as in dialysis unit staff.From June to September 2012, we evaluated 74 cases including 61 patients on hemodialysis and 13 dialysis unit staff. Nasal swabs were taken from all cases and were cultured on a blood medium agar. We identified S. aureus based on conventional laboratory methods. For antimicrobial resistance patterns, we used disk diffusion method. Oxacillin MIC, oxacillin and cefoxcitin disk diffusion methods were used for detection of MRSA. Disk approximation test (D-test was applied for the frequency of erythromycin induced clindamycin resistance.S. aureus carrier state was determined in 12 of the 61 patients on hemodialysis (19.67% and 5 of the 13 dialysis unit staffs (38.46%. In hemodialyzed patients, MRSA and MSSA carrier of S. aureus were 6.56% and 13.11%, respectively. All nasal carriage states in studied staffs were MSSA. All isolated S. aureus were found to be sensitive to vancomycin, teicoplanin, and rifampin. However, reduced sensitivity of MRSA isolates to other antibiotics was noted. Resistance frequencies to tested antibiotic was as follows: cefteriaxone and penicillin (100%, tetracycline and doxycilin (75%, gentamicin, cloxacillin, and cefazolin (50%, ciprofloxacin, trimethoprim-sulfamethoxazol, erythromycin, and clindamycin (25%. The resistance rate of isolated MSSA against tested antibiotics was lower than isolated MRSA. Inducible clindamycin resistance was shown in 25% of identified MRSA strains.S. aureus nasal carrier state was lower than former reports from other parts of Iran. The antibiotic resistance patterns also differed, perhaps due to different pattern of administering antibiotics at our hospital. Screening of these patients should be noted as a health priority
Nicholas P Vitko; Richardson, Anthony R.
Staphylococcus aureus is an important bacterial pathogen in the hospital and community settings, especially Staphylococcus aureus clones that exhibit methicillin-resistance (MRSA). Many strains of S. aureus are utilized in the laboratory, underscoring the genetic differences inherent in clinical isolates. S. aureus grows quickly at 37°C with aeration in rich media (e.g. BHI) and exhibits a preference for glycolytic carbon sources. Furthermore, S. aureus has a gold pigmentation, exhibits β-hem...
Deboye O Kolawole
Full Text Available In contrast to developed countries, only limited data on the prevalence, resistance and clonal structure of Staphylococcus aureus are available for African countries. Since S. aureus carriage is a risk factor for postoperative wound infection, patients who had been hospitalized in surgical wards in a Nigerian University Teaching Hospital were screened for S. aureus carriage. All S. aureus isolates were genotyped (spa, agr and assigned to multilocus sequence types (MLST. Species affiliation, methicillin-resistance, and the possession of pyrogenic toxin superantigens (PTSAg, exfoliative toxins (ETs and Panton-Valentine Leukocidin (PVL were analyzed. Of 192 patients screened, the S. aureus carrier rate was 31.8 % (n = 61. Of these isolates, 7 (11.5% were methicillin-resistant (MRSA. The isolates comprised 24 spa types. The most frequent spa types were t064, t084, t311, and t1931, while the most prevalent MLST clonal complexes were CC5 and CC15. The most frequent PTSAg genes detected were seg/sei (41.0% followed by seb (29.5%, sea (19.7%, seh (14.7% and sec (11.5. The difference between the possession of classical and newly described PTSAg genes was not significant (63.9% versus 59.0% respectively; P = 0.602. PVL encoding genes were found in 39.3% isolates. All MRSA isolates were PVL negative, SCCmec types I and VI in MLST CC 5 and CC 30, respectively. Typing of the accessory gene regulator (agr showed the following distribution: agr group 1 (n = 20, group II (n = 17, group III (n = 14 and group IV (n = 10. Compared to European data, enterotoxin gene seb and PVL-encoding genes were more prevalent in Nigerian methicillin-susceptible S. aureus isolates, which may therefore act as potential reservoir for PVL and PTSAg genes.
Bruno F. Robles
Full Text Available The objectives of the study were to evaluate the presence/production of beta-lactamases by both phenotypic and genotypic methods, verify whether results are dependent of bacteria type (Staphylococcus aureus versus coagulase-negative Staphylococcus - CNS and verify the agreement between tests. A total of 200 bacteria samples from 21 different herds were enrolled, being 100 CNS and 100 S. aureus. Beta-lactamase presence/detection was performed by different tests (PCR, clover leaf test - CLT, Nitrocefin disk, and in vitro resistance to penicillin. Results of all tests were not dependent of bacteria type (CNS or S. aureus. Several S. aureus beta-lactamase producing isolates were from the same herd. Phenotypic tests excluding in vitro resistance to penicillin showed a strong association measured by the kappa coefficient for both bacteria species. Nitrocefin and CLT are more reliable tests for detecting beta-lactamase production in staphylococci.
Alexander, Ashlin J; Susan E. Richardson; Alok Sharma; Paolo Campisi
OBJECTIVE: To retrospectively review trends in clindamycin resistance among Staphylococcus aureus head and neck abscesses between January 2000 and June 2008.METHODS: Between January 2000 and June 2008, inpatient and out-patient S aureus isolates were reviewed for antibiotic susceptibility. In particular, cultures from 153 abscesses in the head and neck region were assessed for clindamycin and methicillin resistance patterns.RESULTS: Annual clindamycin resistance rates for all S aureus isolate...
Vautor, Eric; Cockfield, Joshua; Le Maréchal, Caroline; Le Loir, Yves; Chevalier, Marlène; Robinson, D. Ashley; Thiery, Richard; Lindsay, Jodi
Staphylococcus aureus mastitis in dairy sheep ranges from subclinical mastitis to lethal gangrenous mastitis. Neither the S. aureus virulence factors nor the host-factors or the epidemiological events contributing to the different outcomes are known. In a field study in a dairy sheep farm over 21 months, 16 natural isolates of S. aureus were collected from six subclinical mastitis cases, one lethal gangrenous mastitis case, nasal carriage from eight ewes and one isolate from ambient air in th...
Lutterbach, Marcia T.S.; Contador, Luciana S.; Oliveira, Ana Lucia C.; Galvao, Mariana M. [National Institute of Technology (INT), Rio de Janeiro, RJ (Brazil); Pimenta, Gutemberg S. [PETROBRAS, Rio de Janeiro, RJ (Brazil)
Black powder is a term frequently used to refer to residues formed by various types of iron sulfides mixed with contaminants eventually present in the natural gas flow. According to some researchers, the occurrence of black powder in gas pipelines, besides its chemical corrosion origin, can be directly related to the sulfate-reducing bacteria (SRB) metabolism in this environment. A black powder sample was inoculated in a Post gate E medium modified with the addition of thioglycolate. The resulting positive culture was kept in the laboratory for four years until its use. A dilution technique was then performed aiming to isolate an SRB strain. The bacterial strain isolated and identified through DNA sequencing was not an SRB but rather a Shewanella sp. Compared to the sulfate-reducing bacteria group-traditionally considered the foremost responsible for microbially-influenced corrosion (MIC) - Shewanella is a facultative anaerobe and has a versatile metabolism. Shewanella is able to reduce ferric iron and sulfite, oxidize hydrogen gas, and produce hydrogen sulfide; therefore, these bacteria can be responsible for MIC and pit formation. The isolated Shewanella was used in a corrosion experiment, and the corrosion products were characterized by X-ray diffraction, identifying iron sulfides, iron oxides, and sulfur. Our results indicate that the strain isolated, S. putrefaciens, plays a key role in corrosion problems in gas pipelines. (author)