Jesline, A.; John, Neetu P.; Narayanan, P. M.; Vani, C.; Murugan, Sevanan
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major nosocomial pathogens responsible for a wide spectrum of infections and the emergence of bacterial resistance to antibiotics has lead to treatment drawbacks towards large number of drugs. Formation of biofilms is the main contributing factor to antibiotic resistance. The development of reliable processes for the synthesis of zinc oxide nanoparticles is an important aspect of nanotechnology today. Zinc oxide and titanium dioxide nanoparticles comprise well-known inhibitory and bactericidal effects. Emergence of antimicrobial resistance by pathogenic bacteria is a major health problem in recent years. This study was designed to determine the efficacy of zinc and titanium dioxide nanoparticles against biofilm producing methicillin-resistant S. aureus. Biofilm production was detected by tissue culture plate method. Out of 30 MRSA isolates, 22 isolates showed strong biofilm production and 2 showed weak and moderate biofilm formation. Two strong and weak biofilm-producing methicillin-resistant S. aureus isolates were subjected to antimicrobial activity using commercially available zinc and titanium dioxide nanoparticles. Thus, the nanoparticles showed considerably good activity against the isolates, and it can be concluded that they may act as promising, antibacterial agents in the coming years.
Fluorescent amplified fragment length polymorphism (FAFLP genotyping demonstrates the role of biofilm-producing methicillin-resistant periocular Staphylococcus epidermidis strains in postoperative endophthalmitis
Hasnain Seyed E
Full Text Available Abstract Background An observational case series was used to study the virulence characteristics and genotypes of paired Staphylococcus epidermidis isolates cultured from intraocular samples and from periocular environment of patients with postcataract surgery endophthalmitis. Methods Eight S. epidermidis isolates were obtained from three patients (2 from patients #1 and 2 and 4 from patient #3 whose vitreous and/or anterior chamber (AC specimens and preoperative lid/conjunctiva samples were culture positive. Cultures were identified by API-Staph phenotypic identification system and genotypically characterized by Fluorescent Amplified Fragment Length Polymorphism (FAFLP and checked for their antimicrobial susceptibility. The isolates were tested for biofilm-production and methicillin-resistance (MR by PCR amplification of icaAB and mecA gene respectively. Results Four out of eight S. epidermidis strains showed multiple drug resistance (MDR. All the eight strains were PCR positive for mecA gene whereas seven out of eight strains were positive for icaAB genes. In all three patients FAFLP typing established vitreous isolates of S. epidermidis strains to be indistinguishable from the strains isolated from the patient's conjunctival swabs. However, from patient number three there was one isolate (1030b from lid swab, which appeared to be nonpathogenic and ancestral having minor but significant differences from other three strains from the same patient. This strain also lacked icaAB gene. In silico analysis indicated possible evolution of other strains from this strain in the patient. Conclusion Methicillin-resistant biofilm positive S. epidermidis strains colonizing the conjunctiva and eyelid were responsible for postoperative endophthalmitis (POE.
Kirkland, Eugene Brent; Adams, Brian B
Methicillin-resistant Staphylococcus aureus infections have become an increasingly common condition among athletes. Physical contact, shared facilities and equipment, and hygienic practices of athletes all contribute to methicillin-resistant S. aureus transmission among sports participants. This review elucidates the risk factors predisposing to methicillin-resistant S. aureus infection in athletes and provides guidance for treatment and prevention.
Methicillin-resistant Staphylococcus aureus; Hospital-acquired MRSA (HA-MRSA); Staph - MRSA; Staphylococcal - MRSA ... Que YA, Moreillon P. Staphylococcus aureus (including ... MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice ...
Helen W. Boucher; G. Ralph Corey
The frequency of methicillin-resistant Staphylococcus aureus (MRSA) infections continues to grow in hospital-associated settings and, more recently, in community settings in the United States and globally...
Andersen, Leif Percival; Nielsen, Xiaohui
INTRODUCTION: Even though methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial infections, it may often be difficult to evaluate the exact route of transmission. METHODS: In this study, we describe four cases of nosocomial transmission of MRSA in a hospital with a low...
Liakos, Tracey; Kaye, Keith; Rubin, Adam D
Infections due to methicillin-resistant Staphylococcus aureus (MRSA) have become more prevalent, in part because of the emergence and spread of community-acquired MRSA. This trend is particularly concerning because of the significant rates of morbidity and mortality associated with MRSA infections, and because MRSA strains are often resistant to many classes of antibiotics. Reports of infections of the head and neck, including wound infections, cellulitis, sinusitis, otitis media, and otitis externa, are well documented. However, to our knowledge, there have been no reports of bacterial laryngitis due to MRSA. We report the first published case of bacterial laryngitis caused by MRSA.
Strommenger, Birgit; Bartels, Mette Damkjær; Kurt, Kevin
To elucidate the evolutionary history of Staphylococcus aureus clonal complex (CC) 8, which encompasses several globally distributed epidemic lineages, including hospital-associated methicillin-resistant S. aureus (MRSA) and the highly prevalent community-associated MRSA clone USA300....
Eshetie, Setegn; Tarekegn, Fentahun; Moges, Feleke; Amsalu, Anteneh; Birhan, Wubet; Huruy, Kahsay
The burden of methicillin resistant Staphylococcus aureus is a major public health concern worldwide; however the overall epidemiology of multidrug resistant strains is neither coordinated nor harmonized, particularly in developing countries including Ethiopia. Therefore, the aim of this meta-analysis was to assess the burden of methicillin resistant Staphylococcos aureus and its antibiotic resistance pattern in Ethiopia at large. PubMed, Google Scholar, and lancet databases were searched and a total of 20 studies have been selected for meta-analysis. Six authors have independently extracts data on the prevalence of methicillin resistant Staphylococcus aureus among clinical isolates of Staphylococcus aureus. Statistical analysis was achieved by using Open meta-analyst (version 3.13) and Comprehensive meta-analysis (version 3.3) softwares. The overall prevalence of methicillin resistant Staphylococcus aureus and its antibiotic resistance pattern were pooled by using the forest plot, table and figure with 95% CI. The pooled prevalence of methicillin resistant Staphylococcus aureus was 32.5% (95% CI, 24.1 to 40.9%). Moreover, methicillin resistant Staphylococcus aureus strains were found to be highly resistant to penicillin, ampicillin, erythromycin, and amoxicillin, with a pooled resistance ratio of 99.1, 98.1, 97.2 and 97.1%, respectively. On the other hand, comparably low levels of resistance ratio were noted to vancomycin, 5.3%. The overall burden of methicillin resistant Staphylococcus aureus is considerably high, besides these strains showed extreme resistance to penicillin, ampicillin, erythromycin and amoxicillin. In principle, appropriate use of antibiotics, applying safety precautions are the key to reduce the spread of multidrug resistant strains, methicillin resistant Staphylococcus aureus in particular.
Full Text Available Aim: 127 S.aureus and 65 CoNS strains were isolated from patients noses%u2019. To produce a biofilm ability was investigated using three different methods. Slime-positive and negative staphylococcies%u2019 resistance were evaluated against different antibiotics. Material and Method: Swap samples puted 7% blood agar. Staphylococcus aureus and coagulase-negative staphylococci (CoNS isolates biofilm produced ability were investigated using Congo Red Agar (CRA, microplates (MP and Standard Tube (ST methods. In addition to that, presence of antibiotic resistance of the staphylococcal isolates are determined agar disc diffusion method. Results: The rate of biofilm producing Staphylococcus spp strains was found to be 72.4%, 67.7%, and 62.9%, respectively with CRA, MP, and ST tests. There was no significant relationship among the tests (p>0.05. In addition, antibiotic resistance of Staphylococcus spp. against various antibiotics was also determined by the agar disk diffusion method. Resistance rates of biofilm positive (BP Staphylococcus spp for penicilin G, ampicilin, amocycilin/clavulanic acid, tetracyclin, eritromycin, gentamycin, and enrofloxacin 71.7%, 69.7%, 6.2%, 20.7%, 21.4%, 1.4%, and 0.7%, respectively. Resistance rates of biofilm negative (BN spp for 42.6%, 23.4%, 4.3%, 14.9%, 19.1%, 0.0%, 0.0% respectively. All Staphylococcus isolates were found to be susceptible to vancomycin and teicaplonin. Although BP strains antibiotic resistance rates were observed higher than BN strains. But resistance rates were not found statistically significant (p>0.05. Discussion: CRA is the reliablity and specifity method to determine Staphylococcus spp. biofilm produce ability.
Full Text Available Curcumin, a natural polyphenolic flavonoid extracted from the rhizome of Curcuma longa L., was shown to possess superior potency to resensitize methicillin-resistant Staphylococcus aureus (MRSA to antibiotics. Previous studies have shown the synergistic activity of curcumin with β-lactam and quinolone antibiotics. Further, to understand the anti-MRSA mechanism of curcumin, we investigated the potentiated effect of curcumin by its interaction in diverse conditions. The mechanism of anti-MRSA action of curcumin was analyzed by the viability assay in the presence of detergents, ATPase inhibitors and peptidoglycan (PGN from S. aureus, and the PBP2a protein level was analyzed by western blotting. The morphological changes in the curcumin-treated MRSA strains were investigated by transmission electron microscopy (TEM. We analyzed increased susceptibility to MRSA isolates in the presence of curcumin. The optical densities at 600 nm (OD600 of the suspensions treated with the combinations of curcumin with triton X-100 and Tris were reduced to 63% and 59%, respectively, compared to curcumin without treatment. N,N'-dicyclohexylcarbodiimide (DCCD and sodium azide (NaN3 were reduced to 94% and 55%, respectively. When peptidoglycan (PGN from S. aureus was combined with curcumin, PGN (0–125 μg/mL gradually blocked the antibacterial activity of curcumin (125 μg/mL; however, at a concentration of 125 µg/mL PGN, it did not completely block curcumin. Curcumin has a significant effect on the protein level of PBP2a. The TEM images of MRSA showed damage of the cell wall, disruption of the cytoplasmic contents, broken cell membrane and cell lysis after the treatment of curcumin. These data indicate a remarkable antibacterial effect of curcumin, with membrane permeability enhancers and ATPase inhibitors, and curcumin did not directly bind to PGN on the cell wall. Further, the antimicrobial action of curcumin involved in the PBP2a-mediated resistance mechanism was
A.F. van Belkum (Alex); H.G.M. Niesters (Bert); W.G. MacKay (William); W.B. van Leeuwen (Willem)
textabstractTen samples containing various amounts of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus, methicillin-resistant Staphylococcus epidermidis (MRSE), and combinations thereof were distributed to 51 laboratories for molecular diagnostics testing. Sample
van Belkum, Alex; Niesters, Hubert G M; MacKay, William G; van Leeuwen, Willem B
Ten samples containing various amounts of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus, methicillin-resistant Staphylococcus epidermidis (MRSE), and combinations thereof were distributed to 51 laboratories for molecular diagnostics testing. Samples containing
Full Text Available Some authors reported the possibility of a methicillin-resistant Staphylococcus aureus (MRSA human infections from meat and dairy products and methicillin-resistant Staphylococcus intermedius isolation in animals. The aim of this study is to investigate the methicillin-resistance in S. aureus strains and in S. intermedius strains (food and wild animals. 236 S.aureus strains from food, 36 S.aureus strains and 1 S. intermedius strain from wild animals were analyzed. 2 (0.74% MRSA strains from bovine milk were phenotipically resistant to cefoxitin, grew on chromogenic medium (MRSA Brilliance Oxoid and were mecA positive. All MRSA strains had the spa-type t899. All mecA positive strains showed at least resistance to eight of the antibiotics tested but none to glicopeptides. Both MRSA strains were enterotoxigenic.
Westh, Henrik; Boye, Kit; Bartels, Mette Damkjær
INTRODUCTION: We have found an epidemic increase in methicillin-resistant Staphylococcus aureus (MRSA) in Copenhagen. The increase has a complex background and involves hospitals, nursing homes and persons nursed in their own home. MATERIAL AND METHODS: We found 33 MRSA patients in 2003 and 121...
Hetem, D.J.; Bootsma, M.C.J.; Troelstra, A.; Bonten, M.J.M.
Previous findings have suggested that the nosocomial transmission capacity of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is lower than that of other MRSA genotypes. We therefore performed a 6-month (June 1–November 30, 2011) nationwide study to quantify the single-adm
Full Text Available BACKGROUND: Medical residents may be at risk of becoming colonized by methicillin-resistant Staphylococcus aureus (MRSA during their training. The occupational risk of this specific population is unknown. Furthermore, there are no data regarding MRSA colonization among health care professionals in Quebec.
Deurenberg, R H; Vink, C; Kalenic, S; Friedrich, A W; Bruggeman, C A; Stobberingh, E E
Staphylococcus aureus is a potentially pathogenic bacterium that causes a broad spectrum of diseases. S. aureus can adapt rapidly to the selective pressure of antibiotics, and this has resulted in the emergence and spread of methicillin-resistant S. aureus (MRSA). Resistance to methicillin and other
Full Text Available Abstract Background Methicillin-resistant Staphylococcus aureus is an increasing problem in the Caribbean. We investigated the molecular epidemiology of MRSA isolates on Cuba. Findings The predominant clone was of the spa type t149, followed by community-associated MRSA USA300. Conclusions We report the first molecular typing results of MRSA isolates from Cuba.
Gilani, Mehreen; Usman, Javaid; Latif, Mahwish; Munir, Tehmina; Gill, Maria Mushtaq; Anjum, Rabia; Babar, Nazish
The objective of our study was to determine the frequency of methicillin resistance in coagulase negative Staphylococcus (CoNS) and to determine its in-vitro antimicrobial susceptibility to various other routinely used antibiotics. It was a cross sectional study conducted at the department of Microbiology, Army Medical College, Rawalpindi, Pakistan from June 2011 to May 2012. The organisms were identified on the basis of colony morphology, Gram staining, catalase, DNAase and slide/tube coagulase tests. The organisms were considered to be methicillin resistant when the diameter of zone of inhibition was less than 25mm around 30μg cefoxitin disc. Antibiotic sensitivity was determined using the Modified Kirby-Bauer disc diffusion method. From a total of 337 CoNS, 201 were methicillin resistant and were included in the study. All were resistant to Penicillin, followed by Erythromycin (93•1%), Ciprofloxacin (77%), Co-trimoxazole (74•8%), Gentamicin (68•3%), Clindamycin (51•06%), Tetracycline (44•6%), Fusidic acid (40%), Rifampicin (39•5%), Chloramphenicol (19•3%), Linezolid (2%), Minocycline (1•1%), and Vancomycin (0%). More than half of CoNS were methicillin resistant. Vancomycin is the only drug to which all of the MRCoNS were sensitive, with more than 98% of the isolates being sensitive to Linezolid and Minocycline.
Full Text Available Ahmad M Mansour,1,2 Haytham I Salti11Department of Ophthalmology, American University of Beirut, 2Rafic Hariri University Hospital, Beirut, LebanonAbstract: We present two patients with active, foul-smelling, methicillin-resistant Staphylococcus aureus (MRSA wounds of the forehead and sternum following craniotomy or open heart surgery. Both had debilitating cataracts and were told by the infectious diseases team that cataract surgery is very risky. Both underwent sequential bilateral phacoemulsification with no sign of infection. Patients with active MRSA wound infections may safely undergo cataract surgery with additional precautions observed intraoperatively (good wound construction and postoperatively (topical antibiotics and close observation. Banning such surgeries can unnecessarily jeopardize the lifestyles of such patients.Keywords: cataract, infection, methicillin-resistant Staphylococcus aureus, phacoemulsification
Full Text Available Prostatic abscess is a rarely described condition and is commonly caused by gram-negative organisms such as enterobacteria. However, as the prevalence of methicillin resistant Staphylococcus aureus (MRSA increases in the community, unusual infections due to this organism have been recently published. In this report, we describe a patient with diabetes mellitus type 2, who presents with diabetic ketoacidosis—later found to be due to a prostatic abscess from which MRSA was cultured.
DiCicco, Matthew; Weese, Scott; Neethirajan, Suresh; Rousseau, Joyce; Singh, Ameet
The effectiveness of fosfomycin was examined across 31 methicillin-resistant Staphylococcus pseudintermedius (MRSP) strains by agar dilution. Prevalence of the fosfomycin-resistance determinant gene, fosB, was assessed by PCR analysis. Results found that 84% of isolates were fosfomycin-susceptible. Interestingly, 87% of isolates possessed fosB, indicating no association between this putative staphylococci resistance gene and phenotypic resistance. Further evaluation of fosfomycin as a potential treatment of MRSP in dogs is warranted.
Klitgaard, Janne K; Skov, Marianne N; Kallipolitis, Birgitte H;
Objectives Thioridazine has been shown to reverse oxacillin resistance in methicillin-resistant Staphylococcus aureus (MRSA) in vitro. The aim of this study was to investigate whether thioridazine alone or in combination with oxacillin affects the transcription of the methicillin resistance gene...... mecA and the protein level of the encoded protein PBP2a. Methods Viability of MRSA was determined in liquid media in the presence of oxacillin or thioridazine alone or in combination. Transcription of mecA was analysed by primer extension, and the protein level of PBP2a was analysed by western...... of thioridazine in the presence of a fixed amount of oxacillin. Furthermore, the protein level of PBP2a was reduced when bacteria were treated with the combination of oxacillin and thioridazine. The two drugs also affected the mRNA level of the beta-lactamase gene, blaZ. Conclusions The present study indicates...
Jotić, Ana; Božić, Dragana D; Milovanović, Jovica; Pavlović, Bojan; Ješić, Snežana; Pelemiš, Mijomir; Novaković, Marko; Ćirković, Ivana
Bacterial biofilm formation has been implicated in the high incidence of persistent otorrhoea after tympanostomy tube insertion. The aim of the study was to investigate whether biofilm formation on tympanostomy tubes depends on the genetic profile of methicillin-resistant Staphylococcus aureus (MRSA) strains. Capacity of biofilm formation on fluoroplastic tympanostomy tubes (TTs) was tested on 30 MRSA strains. Identification and methicillin resistance were confirmed by PCR for nuc and mecA genes. Strains were genotypically characterised (SCCmec, agr and spa typing). Biofilm formation was tested in microtiter plate and on TTs. Tested MRSA strains were classified into SCCmec type I (36.7 %), III (23.3 %), IV (26.7 %) and V (13.3 %), agr type I (50 %), II (36.7 %) and III (13.3 %), and 5 clonal complexes (CCs). All tested MRSA strains showed ability to form biofilm on microtiter plate. Capacity of biofilm formation on TTs was as following: 13.3 % of strains belonged to the category of no biofilm producers, 50 % to the category of weak biofilm producers and 36.7 % to moderate biofilm producers. There was a statistically significant difference between CC, SCCmec and agr types and the category of biofilm production on TTs tubes (p biofilm, and CC8 and agrI type with a low amount of biofilm. Biofilm formation by MRSA on TTs is highly dependent on genetic characteristics of the strains. Therefore, MRSA genotyping may aid the determination of the possibility of biofilm-related post-tympanostomy tube otorrhea.
Westh, Henrik; Boye, Kit; Bartels, Mette Damkjær;
in 2004. All isolates have been spa-typed and epidemiologic information collected. RESULTS: The number of MRSA cases has a doubling time of about six months. The epidemic has been caused by many different MRSA types and 31 staphylococcus protein A genotypes (spa types). MRSA has caused several hospital......INTRODUCTION: We have found an epidemic increase in methicillin-resistant Staphylococcus aureus (MRSA) in Copenhagen. The increase has a complex background and involves hospitals, nursing homes and persons nursed in their own home. MATERIAL AND METHODS: We found 33 MRSA patients in 2003 and 121...
Sasaki, Takashi; Kikuchi, Ken; Tanaka, Yoshikazu; Takahashi, Namiko; Kamata, Shinichi; Hiramatsu, Keiichi
We surveyed methicillin-resistant coagulase-positive staphylococcus (MRCPS) strains from 57 (26 inpatient and 31 outpatient) dogs and 20 veterinary staff in a veterinary teaching hospital. From the staff, three MRCPS strains were isolated, and two were methicillin-resistant Staphylococcus aureus (MRSA). In contrast, 18 MRCPS strains were detected in both inpatient (12 of 26 [46.2%]) and outpatient (6 of 31 [19.4%]) dogs. Among them, only one strain was MRSA. Using direct sequencing of sodA and hsp60 genes, the 18 MRCPS strains other than MRSA from a staff and 17 dogs, were finally identified as Staphylococcus pseudintermedius, a novel species of Staphylococcus from a cat. All of the methicillin-resistant S. pseudintermedius (MRSP) strains were multidrug resistant to erythromycin, clindamycin, trimethoprim-sulfamethoxazole, and levofloxacin. Most of the MRSP strains showed high-level resistance to oxacillin (>/=128 mug/ml, 15 of 18 [83.3%]), and 10 of 15 (66.7%) high-level oxacillin-resistant MRSP strains carried type III SCCmec. DNA fingerprinting of MRSP strains by pulsed-field gel electrophoresis yielded eight clusters: clone A with four subtypes, clone B with four subtypes, clone C with three subtypes, and five other different single clones. MRSP strains from the staff and some inpatient and outpatient dogs shared three major clones (clones A, B, and C), but the strains of the other five different clusters were distributed independently among inpatient or outpatient dogs. This genetic diversity suggested that the MRSP strains were not only acquired in this veterinary teaching hospital but also acquired in primary veterinary clinics in the community. To our knowledge, this is the first report of MRSP in dogs and humans in a veterinary institution.
Mansour, Ahmad M; Salti, Haytham I
We present two patients with active, foul-smelling, methicillin-resistant Staphylococcus aureus (MRSA) wounds of the forehead and sternum following craniotomy or open heart surgery. Both had debilitating cataracts and were told by the infectious diseases team that cataract surgery is very risky. Both underwent sequential bilateral phacoemulsification with no sign of infection. Patients with active MRSA wound infections may safely undergo cataract surgery with additional precautions observed intraoperatively (good wound construction) and postoperatively (topical antibiotics and close observation). Banning such surgeries can unnecessarily jeopardize the lifestyles of such patients.
Westh, Henrik; Boye, Kit; Bartels, Mette Damkjær
INTRODUCTION: We have found an epidemic increase in methicillin-resistant Staphylococcus aureus (MRSA) in Copenhagen. The increase has a complex background and involves hospitals, nursing homes and persons nursed in their own home. MATERIAL AND METHODS: We found 33 MRSA patients in 2003 and 121...... to isolation regimes, increase in bed-days and treatment with special antibiotics. After treatment of the infection and in cases of MRSA carriage, MRSA is found on the skin and in the nose. Carriage of MRSA can be eradicated by washing with chlorhexidine and nasal administration of mupirocin. The necessary...
Domínguez, M A; Liñares, J; Martín, R
Methicillin-resistant Staphylococcus aureus (MRSA) strains are among the most common nosocomial pathogens. The most significant mechanism of resistance to methicillin in this-species is the acquisition of a genetic determinant (mecA gene). However, resistance seems to have a more complex molecular basis, since additional chromosomal material is involved in such resistance. Besides, overproduction of penicillinase and/or alterations in the PBPs can contribute to the formation of resistance phenotypes. Genetic and environmental factors leading to MRSA are reviewed.
Pressly, Kalynn B; Hill, Emilie; Shah, Kairav J
A 37-year-old woman with a history of type II diabetes and Crohn's disease, status postcholecystectomy, presented with a >2-week history of cramping abdominal pain, nausea, non-bloody/non-bilious emesis and, later, diarrhoea. A flexible sigmoidoscopy was performed, revealing that 'a segmental pseudomembrane was found from rectum to sigmoid colon'. Clostridium difficile PCR on the stool was repeated twice and resulted negative both times. A food history prior to onset of symptoms was consistent with Staphylococcal food poisoning and a stool culture was positive for heavy growth of methicillin-resistant Staphylococcus aureus and the absence of enteric flora. The patient was successfully treated with oral vancomycin.
Jasmine R. et al.
Full Text Available Even after treating Shingles patients with antiviral drugs, they are found to suffer from secondary bacterial infections. With this background as a guide, we undertook an investigation to isolate the bacterial pathogens from the pus of Shingles patients. Among the isolates obtained during the one year study period, Staphylococcus aureus sp. was found to be multi drug resistant and hence it was chosen for the study. The antibiogram pattern of the methicillin resistant S. aureus was obtained, since this could serve as a tool for suggesting useful drugs.
Alex, Aniltta; Letizia, MariJo
Methicillin-resistant "Staphylococcus aureus" (MRSA) is a disease-causing organism that has been present in hospital settings since the 1960s. However, a genetically distinct strain of MRSA, called community-acquired methicillin-resistant "Staphylococcus aureus" (CA-MRSA), has emerged in recent years in community settings among healthy…
Wang, Yucheng; Dai, Tianhong; Gu, Ying
Background: With the increasing emergence of multidrug-resistant (MDR) bacterial strains, there is a pressing need for the development of alternative treatment for infections. Antimicrobial blue light (aBL) has provided a simple and effective approach. Methods: We first investigated the effectiveness of aBL (415 nm) inactivation of USA300 LAClux (a communityacquired Methicillin-resistant Staphylococcus aureus strain) both in the planktonic and biofilm forms. The survival of the bacteria in suspensions was determined by serial dilution and that of the biofilm-embedded bacteria was determined by bioluminescence quantification. Using a mouse model of thermal burn infected with USA300 LAClux, we further assessed the effectiveness of aBL for treating localized infections. Bioluminescence imaging was performed to monitor in real time bacterial viability in vivo. Results: In vitro study showed that, for the planktonic counterpart of the bacteria or the 24-h-old biofilms, an irradiance of 55 mW/cm2 for 60 min resulted in a 4.61 log10 or 2.56 log10 inactivation, respectively. In vivo study using infected mouse burns demonstrated that a 2.56-log10 inactivation was achieved after 100-mW/cm2 irradiation for 62 min. Conclusions: aBL is a potential alternative approach for treating Methicillin-resistant Staphylococcus aureus infections.
Cheong, I; Tan, S C; Wong, Y H; Zainudin, B M; Rahman, M Z
Between August 1990 to November 1991, 905 of 2583 (35.4%) isolates of Staphylococcus aureus were found to be methicillin-resistant in a general hospital in Malaysia. A detailed study of 539 of these isolates showed a high prevalence of methicillin resistant Staphylococcus aureus (MRSA) in the surgical/orthopaedic wards, paediatric wards and the special care unit. The yield of MRSA was highest from wounds/ulcers/skin swabs accounting for 64.2 per cent followed by 6.9 per cent in blood cultures. Vancomycin remains the drug of choice with no resistance detected. The resistance to ciprofloxacin was 6.7 per cent, rifampicin 4.5 per cent and fusidic acid 2.0 per cent. Most isolates were resistant to aminoglycosides. In view of the high prevalence of MRSA in this hospital, the authorities must introduce more effective measures to control its spread as a nosocomial pathogen. Otherwise it may seriously disrupt the efficient delivery of health care services in the country.
Qin, Li; Da, Fei; Tan, Daniel C. S.; Nguyen, Thuan H.; Fu, Chih-Lung; Tan, Vee Y.; Sturdevant, Daniel E.
Bacterial sepsis is a major killer in hospitalized patients. Coagulase-negative staphylococci (CNS) with the leading species Staphylococcus epidermidis are the most frequent causes of nosocomial sepsis, with most infectious isolates being methicillin-resistant. However, which bacterial factors underlie the pathogenesis of CNS sepsis is unknown. While it has been commonly believed that invariant structures on the surface of CNS trigger sepsis by causing an over-reaction of the immune system, we show here that sepsis caused by methicillin-resistant S. epidermidis is to a large extent mediated by the methicillin resistance island-encoded peptide toxin, PSM-mec. PSM-mec contributed to bacterial survival in whole human blood and resistance to neutrophil-mediated killing, and caused significantly increased mortality and cytokine expression in a mouse sepsis model. Furthermore, we show that the PSM-mec peptide itself, rather than the regulatory RNA in which its gene is embedded, is responsible for the observed virulence phenotype. This finding is of particular importance given the contrasting roles of the psm-mec locus that have been reported in S. aureus strains, inasmuch as our findings suggest that the psm-mec locus may exert effects in the background of S. aureus strains that differ from its original role in the CNS environment due to originally “unintended” interferences. Notably, while toxins have never been clearly implied in CNS infections, our tissue culture and mouse infection model data indicate that an important type of infection caused by the predominant CNS species is mediated to a large extent by a toxin. These findings suggest that CNS infections may be amenable to virulence-targeted drug development approaches. PMID:28151994
Boyce, J M
In areas where the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) is very low, aggressive strategies, which appear to have been effective, such as those used in the Netherlands and western Australia, may be feasible. In hospitals where MRSA is epidemic or highly endemic, less rigorous strategies are appropriate. However, which isolation techniques and barrier precautions are optimal is controversial. In addition, there is no consensus regarding the epidemiological importance of environmental contamination. Rapid detection of MRSA, prompt implementation of barrier precautions and prospective surveillance are essential components of a successful control programme. Eradicating nasal carriage of MRSA among patients and personnel can be useful during epidemics, but the cost-effectiveness of using this approach in hospitals where the prevalence of MRSA is low is unknown. Additional studies of this issue need to include surveillance for mupirocin-resistant strains.
Full Text Available We collected and analyzed 500 samples of human milk, from five Brazilian cities (100 from each to detect methicillin-resistant strains of Staphylococcus aureus (MRSA producing enterotoxins. We found 57 strains of MRSA, and the mecA gene, responsible for resistance, was detected in all of them using a specific molecular probe. We examined 40 strains for the presence of four enterotoxins, after selecting a subset that included all strains from each region, except for the largest sample, from which 10 were randomly selected. Among these two presented enterotoxin B, and growth in human colostrum and trypicase soy broth. After 5 h of incubation at 37°C, population sizes were already higher than 9.4 x 105 UFC/ml and enterotoxin was released into culture medium and colostrum. Our results stress the importance of hygiene, sanitary measures, and appropriate preservation conditions to avoid the proliferation of S. aureus in human milk.
Atkinson Smith, Mary
In the specialty of orthopaedics, methicillin-resistant Staphylococcus aureus (MRSA) is a major contributor to infections of the soft tissues, surgical sites, and joints, in addition to increasing disability, mortality, and healthcare costs. Inappropriate prescribing and misuse of antibiotics have led to bacterial resistance and the rapid emergence of MRSA. It is imperative for healthcare providers and facilities to improve quality, promote safety, and decrease costs related to MRSA infections. The healthcare profession and society as a whole play an important role in minimizing the transmission of pathogens, reducing the incidence of MRSA infections, and decreasing the development of future antibiotic resistant pathogens. This article discusses the epidemiology of MRSA and describes evidence-based guidelines pertaining to the prevention, minimization, and treatment of MRSA-related infections. Specific application to orthopaedics are discussed in the context of patient risk factors, perioperative and postoperative prophylaxis, and current trends regarding education and reporting strategies.
Barbarin, Alexis M; Hu, Baofeng; Nachamkin, Irving; Levy, Michael Z
A recent paper published by Lowe and Romney in Emerging Infectious Diseases titled, Bed bugs as Vectors for Drug-Resistant Bacteria has sparked a renewed interest in bed bug vector potential. We followed a pyrethroid resistant strain of the human bed bug (Cimex lectularius, L.) fed either human blood or human blood with added methicillin resistant Staphylococcus aureus (MRSA) for 9 days post-feeding. Results indicated that while the bed bug midgut is a hospitable environment for MRSA, the bacteria does not survive longer than 9 days within the midgut. Additionally, MRSA is not amplified within the midgut of the bug as the infection was cleared within 9 days. Due to the weekly feeding behaviours of bed bugs, these results suggest that bed bug transmission of MRSA is highly unlikely.
Sowash, Madeleine G.; Uhlemann, Anne-Catrin
Over the past decade, the emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has changed the landscape of S. aureus infections around the globe. Initially recognized for its ability to cause disease in young and healthy individuals without healthcare exposures as well as for its distinct genotype and phenotype, this original description no longer fully encompasses the diversity of CA-MRSA as it continues to expand its niche. Using four case studies, we highlight a wide range of the clinical presentations and challenges of CA-MRSA. Based on these cases we further explore the globally polygenetic background of CA-MRSA with a special emphasis on generally less characterized populations. PMID:24085688
Chan, Liana C; Basuino, Li; Diep, Binh; Hamilton, Stephanie; Chatterjee, Som S; Chambers, Henry F
The role of mecA mutations in conferring resistance to ceftobiprole and ceftaroline, cephalosporins with anti-methicillin-resistant Staphylococcus aureus (MRSA) activity, was determined with MRSA strains COL and SF8300. The SF8300 ceftaroline-passaged mutant carried a single mecA mutation, E447K (E-to-K change at position 447), and expressed low-level resistance. This mutation in COL conferred high-level resistance to ceftobiprole but only low-level resistance to ceftaroline. The COL ceftaroline-passaged mutant, which expressed high-level resistance to ceftobiprole and ceftaroline, had mutations in pbp2, pbp4, and gdpP but not mecA.
Soong, Grace; Paulino, Franklin; Wachtel, Sarah; Parker, Dane; Wickersham, Matthew; Zhang, Dongni; Brown, Armand; Lauren, Christine; Dowd, Margaret; West, Emily; Horst, Basil; Planet, Paul; Prince, Alice
Skin is the most common site of Staphylococcus aureus infection. While most of these infections are self-limited, recurrent infections are common. Keratinocytes and recruited immune cells participate in skin defense against infection. We postulated that S. aureus is able to adapt to the milieu within human keratinocytes to avoid keratinocyte-mediated clearance. From a collection of S. aureus isolated from chronically infected patients with atopic dermatitis, we noted 22% had an agr mutant-like phenotype. Using several models of human skin infection, we demonstrate that toxin-deficient, agr mutants of methicillin-resistant S. aureus (MRSA) USA300 are able to persist within keratinocytes by stimulating autophagy and evading caspase-1 and inflammasome activation. MRSA infection induced keratinocyte autophagy, as evidenced by galectin-8 and LC3 accumulation. Autophagy promoted the degradation of inflammasome components and facilitated staphylococcal survival. The recovery of more than 58% agr or RNAIII mutants (P keratinocytes compared to control keratinocytes reflected the survival advantage for mutants no longer expressing agr-dependent toxins. Our results illustrate the dynamic interplay between S. aureus and keratinocytes that can result in the selection of mutants that have adapted specifically to evade keratinocyte-mediated clearance mechanisms. Human skin is a major site of staphylococcal infection, and keratinocytes actively participate in eradication of these pathogens. We demonstrate that methicillin-resistant Staphylococcus aureus (MRSA) is ingested by keratinocytes and activates caspase-1-mediated clearance through pyroptosis. Toxin-deficient MRSA mutants are selected within keratinocytes that fail to induce caspase-1 activity and keratinocyte-mediated clearance. These intracellular staphylococci induce autophagy that enhances their intracellular survival by diminishing inflammasome components. These findings suggest that S. aureus mutants, by exploiting
H.F.L. Wertheim (Heiman); H.A. Verbrugh (Henri); C. van Pelt (Cindy); P. de Man (Peter); A.F. van Belkum (Alex); M.C. Vos (Margreet)
textabstractWe tested a phenyl mannitol broth containing ceftizoxime and aztreonam (PHMB(+)) for detection of methicillin-resistant Staphylococcus aureus (MRSA) with reference MRSA strains and, subsequently, with clinical samples (n = 1,098). All reference MRSA strains
H.S.M. Ammerlaan; J.A.J.W. Kluytmans; H. Berkhout; A. Buiting; E.I.G.B. de Brauwer; P.J. van den Broek; P. van Gelderen; S.C.A.P. Leenders; A. Ott; C.J.J. Richter; L. Spanjaard; I.J.B. Spijkerman; F.H. van Tiel; G.P. Voorn; M.W.H. Wulf; J. van Zeijl; A. Troelstra; M.J.M. Bonten
Background: Using data from an observational study in which the effectiveness of a guideline for eradication of methicillin-resistant Staphylococcus aureus (MRSA) carriage was evaluated, we identified variables that were associated with treatment failure. Methods: A multivariate logistic regression
H.F.L. Wertheim (Heiman); H.A. Verbrugh (Henri); C. van Pelt (Cindy); P. de Man (Peter); A.F. van Belkum (Alex); M.C. Vos (Margreet)
textabstractWe tested a phenyl mannitol broth containing ceftizoxime and aztreonam (PHMB(+)) for detection of methicillin-resistant Staphylococcus aureus (MRSA) with reference MRSA strains and, subsequently, with clinical samples (n = 1,098). All reference MRSA strains
P L Mehndiratta
Full Text Available Increasing prevalence of Methicillin-resistant Staphylococcus aureus (MRSA worldwide is a growing public health concern. MRSA typing is an essential component of an effective surveillance system to describe epidemiological trends and infection control strategies. Current challenges for MRSA typing are focused on selecting the most appropriate technique in terms of efficiency, reliability, ease of performance and cost involved. This review summarises the available information on application, potential and problems of various typing techniques in discriminating the strains and understanding the epidemiology of MRSA strains. The phenotypic methods in general are easier to perform, easier to interpret, cost effective and are widely available, however less discriminatory. The genotypic methods are expensive and technically demanding, however more discriminatory. Newer technologies involving sequencing of various genes are coming up as broadly applicable and high throughput typing systems. Still there is no consensus regarding the single best method for typing of MRSA strains. Phage typing is recommended as first line approach in epidemiological investigation of MRSA strains. PFGE remains the gold standard for characterisation of outbreak strains. DNA sequencing methods including MLST, spa typing, SCCmec typing and toxin gene profile typing are more practical methods for detecting evolutionary changes and transmission events. The choice of typing technique further depends on the purpose of the study, the facilities available and the utility of data generated to answer a desirable research question. A need for harmonisation of typing techniques by following standard protocols is emphasised to establish surveillance networks and facilitate global MRSA control.
Wendlandt, Sarah; Schwarz, Stefan; Silley, Peter
Prior to the 1990s, most methicillin-resistant Staphylococcus aureus (MRSA) was hospital-associated (HA-MRSA); community-associated MRSA (CA-MRSA) then began to cause infections outside the health-care environment. The third significant emergence of MRSA has been in livestock animals [livestock-associated MRSA (LA-MRSA)]. The widespread and rapid growth in CA-MRSA and LA-MRSA has raised the question as to whether MRSA is indeed a food-borne pathogen. The observations on animal-to-animal and animal-to-human transfer of LA-MRSA have prompted research examining the origin of LA-MRSA and its capacity to cause zoonotic disease in humans. This review summarizes the current knowledge about MRSA from food-producing animals and foods with respect to the role of these organisms to act as food-borne pathogens and considers the available tools to track the spread of these organisms. It is clear that LA-MRSA and CA-MRSA and even HA-MRSA can be present in/on food intended for human consumption, but we conclude on the basis of the published literature that this does not equate to MRSA being considered a food-borne pathogen.
Okuda, Ken-ichi; Zendo, Takeshi; Sugimoto, Shinya; Iwase, Tadayuki; Tajima, Akiko; Yamada, Satomi; Sonomoto, Kenji; Mizunoe, Yoshimitsu
Control of biofilms formed by microbial pathogens is an important subject for medical researchers, since the development of biofilms on foreign-body surfaces often causes biofilm-associated infections in patients with indwelling medical devices. The present study examined the effects of different kinds of bacteriocins, which are ribosomally synthesized antimicrobial peptides produced by certain bacteria, on biofilms formed by a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA). The activities and modes of action of three bacteriocins with different structures (nisin A, lacticin Q, and nukacin ISK-1) were evaluated. Vancomycin, a glycopeptide antibiotic used in the treatment of MRSA infections, showed bactericidal activity against planktonic cells but not against biofilm cells. Among the tested bacteriocins, nisin A showed the highest bactericidal activity against both planktonic cells and biofilm cells. Lacticin Q also showed bactericidal activity against both planktonic cells and biofilm cells, but its activity against biofilm cells was significantly lower than that of nisin A. Nukacin ISK-1 showed bacteriostatic activity against planktonic cells and did not show bactericidal activity against biofilm cells. Mode-of-action studies indicated that pore formation leading to ATP efflux is important for the bactericidal activity against biofilm cells. Our results suggest that bacteriocins that form stable pores on biofilm cells are highly potent for the treatment of MRSA biofilm infections.
Porrero, M C; Wassenaar, T M; Gómez-Barrero, S; García, M; Bárcena, C; Alvarez, J; Sáez-Llorente, J L; Fernández-Garayzábal, J F; Moreno, M A; Domínguez, L
Iberian pigs are bred in Spain for the production of high-value dry-cured products, whose export volumes are increasing. Animals are typically reared outdoors, although indoor farming is becoming popular. We compared carriage of methicillin-resistant Staphylococcus aureus (MRSA) in Iberian pigs, raised indoors and outdoors, with intensively farmed Standard White pigs. From June 2007 to February 2008, 106 skin swabs were taken from Iberian pigs and 157 samples from SWP at slaughterhouses in Spain. We found that Iberian pigs carried MRSA, although with a significantly lower prevalence (30/106; 28%) than SWP (130/157; 83%). A higher prevalence of indoor Iberian pigs compared with animals reared under outdoor conditions was not significant; however, all but one positive indoor Iberian pig samples were detected from one slaughterhouse. Overall, 16 different spa types were identified, with t011 predominating in all three animal populations. A subset of isolates was characterized by MLST. Most of these belonged to ST398. MRSA isolates from Iberian pigs presented a higher susceptibility to antibiotics than those isolated from SWP. Despite limited contact with humans, pigs raised outdoors are colonized by an MRSA population that genetically overlaps with that of intensively farmed pigs, although antimicrobial resistance is lower. To our knowledge, this is the first detection of MRSA in food animals raised in free-range conditions. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.
Full Text Available From the mid-2000s on, numerous studies have shown that methicillin-resistant Staphylococcus aureus (MRSA, renowned as human pathogen, has a reservoir in pigs and other livestock. In Europe and North America, clonal complex (CC 398 appears to be the predominant lineage involved. Especially worrisome is its capacity to contaminate humans in close contact with affected animals. Indeed, the typical multi-resistant phenotype of MRSA CC398 and its observed ability of easily acquiring genetic material suggests that MRSA CC398 strains with an increased virulence potential may emerge, for which few therapeutic options would remain. This questions the need to implement interventions to control the presence and spread of MRSA CC398 among pigs. MRSA CC398 shows a high but not fully understood transmission potential in the pig population and is able to persist within that population. Although direct contact is probably the main route for MRSA transmission between pigs, also environmental contamination, the presence of other livestock, the herd size and farm management are factors that may be involved in the dissemination of MRSA CC398. The current review aims at summarizing the research that has so far been done on the transmission dynamics and risk factors for introduction and persistence of MRSA CC398 in farms.
Keli Cristine Reiter
Full Text Available INTRODUCTION: Antimicrobial activity on biofilms depends on their molecular size, positive charges, permeability coefficient, and bactericidal activity. Vancomycin is the primary choice for methicillin-resistant Staphylococcus aureus (MRSA infection treatment; rifampicin has interesting antibiofilm properties, but its effectivity remains poorly defined. METHODS: Rifampicin activity alone and in combination with vancomycin against biofilm-forming MRSA was investigated, using a twofold serial broth microtiter method, biofilm challenge, and bacterial count recovery. RESULTS: Minimal inhibitory concentration (MIC and minimal bactericidal concentration for vancomycin and rifampicin ranged from 0.5 to 1mg/l and 0.008 to 4mg/l, and from 1 to 4mg/l and 0.06 to 32mg/l, respectively. Mature biofilms were submitted to rifampicin and vancomycin exposure, and minimum biofilm eradication concentration ranged from 64 to 32,000 folds and from 32 to 512 folds higher than those for planktonic cells, respectively. Vancomycin (15mg/l in combination with rifampicin at 6 dilutions higher each isolate MIC did not reach in vitro biofilm eradication but showed biofilm inhibitory capacity (1.43 and 0.56log10 CFU/ml reduction for weak and strong biofilm producers, respectively; p<0.05. CONCLUSIONS: In our setting, rifampicin alone failed to effectively kill biofilm-forming MRSA, demonstrating stronger inability to eradicate mature biofilm compared with vancomycin.
Popoola, Victor O.; Carroll, Karen C.; Ross, Tracy; Reich, Nicholas G.; Perl, Trish M; Milstone, Aaron M.
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.
Lersy López Gutierrez; Alfonso Bettin Martinez; Héctor Suárez Mahecha
To determine the prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) isolated in establishments that commercialize raw ground beef and pork chops in Cartagena- Colombia. 160 samples were analyzed through microbiological cultures in Baire Parcker agar, and it was determined the presence of mecA gen that codifies the methicillin resistance and the pvl that codifies the Panton- Valentine leukocidin toxin (PVL) by the multiplex PCR technique. The antibiotic susceptibility profile for...
Laura M Laarhoven
Full Text Available Methicillin-resistant Staphylococcus pseudintermedius (MRSP is an emerging pathogen in dogs and has been found in Europe, Asia and North America. To date most studies are one-point prevalence studies and therefore little is known about the dynamics of MRSP in dogs and their surrounding. In this longitudinal study MRSP colonization in dogs and the transmission of MRSP to humans, contact animals and the environment was investigated. Sixteen dogs with a recent clinical MRSP infection were included. The index dogs, contact animals, owners and environments were sampled once a month for six months. Samples taken from the nose, perineum and infection site (if present of the index cases and contact animals, and the nares of the owners were cultured using pre-enrichment. Index cases were found positive for prolonged periods of time, in two cases during all six samplings. In five of the 12 households that were sampled during six months, the index case was intermittently found MRSP-positive. Contact animals and the environment were also found MRSP-positive, most often in combination with a MRSP-positive index dog. In four households positive environmental samples were found while no animals or humans were MRSP-positive, indicating survival of MRSP in the environment for prolonged periods of time. Genotyping revealed that generally similar or indistinguishable MRSP isolates were found in patients, contact animals and environmental samples within the same household. Within two households, however, genetically distinct MRSP isolates were found. These results show that veterinarians should stay alert with (former MRSP patients, even after repeated MRSP-negative cultures or after the disappearance of the clinical infection. There is a considerable risk of transmission of MRSP to animals in close contact with MRSP patients. Humans were rarely MRSP-positive and never tested MRSP-positive more than once suggesting occasional contamination or rapid elimination of
Springer, Burkhard; Orendi, Ulrike; Much, Peter; Höger, Gerda; Ruppitsch, Werner; Krziwanek, Karina; Metz-Gercek, Sigrid; Mittermayer, Helmut
Staphylococcus aureus is a major cause of infection in hospitals and the community. One third of the general population is colonized by the bacterium, constituting a risk factor for acquisition of infection with this pathogen. Worldwide, the increasing antibiotic resistance of S. aureus complicates treatment of infection and control measures. Soon after the introduction of methicillin, the first isolates resistant to this antibiotic were reported and named methicillin-resistant S. aureus (MRSA). During the past decade a major change in MRSA epidemiology has been observed: whereas in the past MRSA was almost exclusively regarded a hospital pathogen, the advent of community-acquired MRSA has led to infections in people without hospital-related risk factors. Recent evidence has also identified a link between colonization of livestock and MRSA carriage and infections in people who work with animals. Screening of pigs and pig farmers in the Netherlands revealed high prevalence of MRSA sequence type (ST) 398 and it has become clear that the emergence of ST398 is not just a Dutch problem, as reports on livestock colonization and human infections are appearing worldwide. In Austria, the ST398 lineage has been detected in dust samples from pig breeding facilities and in food samples. Since the first Austrian detection of this emerging lineage in 2006, 21 human isolates, partially associated with infections, have been observed. MRSA has to be regarded as a new emerging zoonotic agent and livestock may constitute a growing reservoir of the ST398 lineage. More information is needed so that control measures to reduce the impact of the emerging MRSA ST398 lineage on public health can be developed and implemented.
Full Text Available Amicoumacin A exhibits strong antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA, hence we sought to uncover its mechanism of action. Genome-wide transcriptome analysis of S. aureus COL in response to amicoumacin A showed alteration in transcription of genes specifying several cellular processes including cell envelope turnover, cross-membrane transport, virulence, metabolism, and general stress response. The most highly induced gene was lrgA, encoding an antiholin-like product, which is induced in cells undergoing a collapse of Δψ. Consistent with the notion that LrgA modulates murein hydrolase activity, COL grown in the presence of amicoumacin A showed reduced autolysis, which was primarily caused by lower hydrolase activity. To gain further insight into the mechanism of action of amicoumacin A, a whole genome comparison of wild-type COL and amicoumacin A-resistant mutants isolated by a serial passage method was carried out. Single point mutations generating codon substitutions were uncovered in ksgA (encoding RNA dimethyltransferase, fusA (elongation factor G, dnaG (primase, lacD (tagatose 1,6-bisphosphate aldolase, and SACOL0611 (a putative glycosyl transferase. The codon substitutions in EF-G that cause amicoumacin A resistance and fusidic acid resistance reside in separate domains and do not bring about cross resistance. Taken together, these results suggest that amicoumacin A might cause perturbation of the cell membrane and lead to energy dissipation. Decreased rates of cellular metabolism including protein synthesis and DNA replication in resistant strains might allow cells to compensate for membrane dysfunction and thus increase cell survivability.
Recent efforts to combat infections have focused on pharmaceutical interventions. However, the global spread of antimicrobial resistance calls for the reappraisal of personal and institutional hygiene. Hygiene embodies behavioural and procedural rules that prevent bacterial transmission. Consequently, the chance of spreading bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) is significantly reduced. Hygiene is part of the primacy and totality of patient care, ensuring that no harm is done. Any prevention and control strategy must be underpinned by changes in attitude, embraced by all. The major components of preventing and controlling MRSA include hand and environmental hygiene (as part of standard precautions), patient isolation, and patient\\/staff decolonization. Improving hand hygiene practice is especially important where the risk of infection is highest, e.g. in intensive care. Physical isolation has two advantages: the physical barrier interrupts transmission, and this barrier emphasizes that precautions are required. With limited isolation facilities, risk assessment should be conducted to indicate which patients should be isolated. Environmental hygiene, although important, has a lower priority than standard precautions. When a patient is ready for discharge (home) or transfer (to another healthcare facility), the overall interests of the patient should take priority. All patients should be informed of their MRSA-positive status as soon as possible. Because of increased mupirocin resistance, a selective approach to decolonization should be taken. When MRSA-positive staff are identified, restricting their professional activity will depend on the nature of their work. Finally, politicians and others need to commit to providing the necessary resources to maximize MRSA prevention and control.
Bartels, Mette Damkjaer; Boye, Kit; Rhod Larsen, Anders;
by pulsed-field gel electrophoresis, Staphylococcus protein A (spa) typing, multilocus sequence typing, staphylococcal chromosome cassette (SCC) mec typing, and detection of Panton-Valentine leukocidin (PVL) genes. Seventy-one percent of cases were community-onset MRSA (CO-MRSA); of these, 36% had......In Copenhagen, methicillin-resistant Staphylococcus aureus (MRSA) accounted for
Bartels, Mette Damkjær; Boye, Kit; Larsen, Anders Rhod;
by pulsed-field gel electrophoresis, Staphylococcus protein A (spa) typing, multilocus sequence typing, staphylococcal chromosome cassette (SCC) mec typing, and detection of Panton-Valentine leukocidin (PVL) genes. Seventy-one percent of cases were community-onset MRSA (CO-MRSA); of these, 36% had......In Copenhagen, methicillin-resistant Staphylococcus aureus (MRSA) accounted for
Dayane de Melo Costa
Full Text Available The aim of the study was to analyze epidemiological and microbiological aspects of oral colonization by methicillin-resistant Staphylococcus of health care workers in a cancer hospital. Interview and saliva sampling were performed with 149 health care workers. Antimicrobial resistance was determined by disk diffusion and minimum inhibitory concentration. Polymerase Chain Reaction, Internal Transcribed Spacer-Polymerase Chain Reaction and Pulsed Field Gel Electrophoresis were performed for genotypic characterization of methicillin-resistant Staphylococcus. Risk factors were determined by logistic regression. Methicillin-resistant Staphylococcus colonization prevalence was 19.5%, denture wearing (p = 0.03, habit of nail biting (p = 0.04 and preparation and administration of antimicrobial (p = 0.04 were risk factors identified. All methicillin-resistant Staphylococcus were S. epidermidis, 94.4% of them had mecA gene. Closely related and indistinguishable methicillin-resistant S. epidermidis were detected. These results highlight that HCWs which have contact with patient at high risk for developing infections were identified as colonized by MRSE in the oral cavity, reinforcing this cavity as a reservoir of these bacteria and the risk to themselves and patients safety, because these microorganisms may be spread by coughing and talking.
Costa, Dayane de Melo; Kipnis, André; Leão-Vasconcelos, Lara Stefânia Netto de Oliveira; Rocha-Vilefort, Larissa Oliveira; Telles, Sheila Araújo; André, Maria Cláudia Dantas Porfírio Borges; Tipple, Anaclara Ferreira Veiga; Lima, Ana Beatriz Mori; Ribeiro, Nádia Ferreira Gonçalves; Pereira, Mayara Regina; Prado-Palos, Marinésia Aparecida
The aim of the study was to analyze epidemiological and microbiological aspects of oral colonization by methicillin-resistant Staphylococcus of health care workers in a cancer hospital. Interview and saliva sampling were performed with 149 health care workers. Antimicrobial resistance was determined by disk diffusion and minimum inhibitory concentration. Polymerase Chain Reaction, Internal Transcribed Spacer-Polymerase Chain Reaction and Pulsed Field Gel Electrophoresis were performed for genotypic characterization of methicillin-resistant Staphylococcus. Risk factors were determined by logistic regression. Methicillin-resistant Staphylococcus colonization prevalence was 19.5%, denture wearing (p = 0.03), habit of nail biting (p = 0.04) and preparation and administration of antimicrobial (p = 0.04) were risk factors identified. All methicillin-resistant Staphylococcus were S. epidermidis, 94.4% of them had mecA gene. Closely related and indistinguishable methicillin-resistant S. epidermidis were detected. These results highlight that HCWs which have contact with patient at high risk for developing infections were identified as colonized by MRSE in the oral cavity, reinforcing this cavity as a reservoir of these bacteria and the risk to themselves and patients safety, because these microorganisms may be spread by coughing and talking. PMID:25477910
Renata Tavares Gomes
Full Text Available Methicillin-resistant Staphylococcus aureus has emerged as a pathogen associated with community-acquired infections worldwide. We report the spectrum of community-acquired S. aureus infections and compare the patients infected with methicillin-susceptible or methicillin-resistant strains among patients aged <20 years. Overall, 90 cases of community acquired S. aureus were detected in an 11-year period. Clinical and microbiological data were registered. Fifty-nine (66% patients were male and the median age was two years. The majority (87% of the patients were hospitalized and chronic underlying illnesses were detected in 27 (30% cases. Overall, 34 (37.8% patients had skin/soft tissue infections and 56 (62.2% patients had deep-seated infection. Four (5.1% patients were transferred to the intensive care unit and two (2.6% died. Complications were detected in 17 (18.9% cases, such as pleural effusion (41.2%, osteomyelitis (23.5%, and sepsis (17.6%. Six (6.7% methicillin-resistant strains were detected. Patients infected with methicillin-susceptible or methicillin-resistant strains had similar baseline characteristics and treatment outcomes. Approximately 93% of the cases received systemic antibiotics, out of which 59 (65.5% used oxacillin or cefalotin. Both methicillin-susceptible and methicillin-resistant S. aureus strains resulted in morbidity and death among children in this setting where methicillin-resistant strains are infrequent.
Spoor, Laura E.; McAdam, Paul R.; Weinert, Lucy A.;
ABSTRACT The importance of livestock as a source of bacterial pathogens with the potential for epidemic spread in human populations is unclear. In recent years, there has been a global increase in community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections of healthy...... of emergent clones of methicillin-resistant Staphylococcus aureus (MRSA) that originated in livestock and switched to humans, followed by host-adaptive evolution and epidemic spread in global human populations. Our findings demonstrate that livestock can act as a reservoir for the emergence of new human...
Sergelidis, D; Abrahim, A; Papadopoulos, T; Soultos, N; Martziou, E; Koulourida, V; Govaris, A; Pexara, A; Zdragas, A; Papa, A
A hundred samples from ready-to-eat (RTE) fish products were examined for the presence and antimicrobial susceptibility of Staphylococcus spp. Staphylococci were isolated from 43% of these samples (n = 100). The identified species in the samples were Staphylococcus aureus (7%), Staphylococcus epidermidis (13%), Staphylococcus xylosus (12%), Staphylococcus sciuri (4%), Staphylococcus warneri (3%), Staphylococcus saprophyticus (2%), Staphylococcus schleiferi (1%) and Staphylococcus auricularis (1%). Two Staph. aureus (MRSA) isolates, three Staph. epidermidis (MRSE), five Staph. xylosus, four Staph. sciuri, one Staph. schleiferi and one Staph. saprophyticus isolates were resistant to oxacillin and all of them carried the mecA gene. The two MRSA isolates belonged to the spa types t316 (ST359) and t548 (ST5) and none of them was able to produce enterotoxins. Pulsed field gel electrophoresis for Staph. aureus and Staph. epidermidis isolates revealed 6 and 11 distinct PFGE types, respectively, reflecting diversity. The presence of methicillin-resistant staphylococci, especially MRSA and MRSE, in RTE fish products may constitute a potential health risk for consumers. This study provides the first data on the occurrence of methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci in salted and smoked fish products in Greece. These results are important and useful for Staphylococcus spp. risk assessment and management programmes for ready-to-eat fish products. © 2014 The Society for Applied Microbiology.
Paul, Narayan Chandra; Moodley, Arshnee; Ghibaudo, G.
Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is increasingly reported in small animals and cases of human infections have already been described despite its recent emergence in veterinary practice. We investigated the prevalence of MRSP and methicillin-resistant Staphylococcus...... aureus (MRSA) among small animal dermatologists attending a national veterinary conference in Italy. Nasal swabs were obtained from 128 veterinarians, seven of which harboured MRSP (n = 5; 3.9%) or MRSA (n = 2; 1.6%). A follow-up study of two carriers revealed that MRSP persisted for at least 1 month...... by spa typing. Methicillin-resistant isolates were further typed by antimicrobial susceptibility testing, SCCmec and multi-locus sequence typing. Two lineages previously associated with pets were identified among the five MRSP isolates; the European epidemic clone ST71-SCCmec II-III and ST106-SCCmec IV...
NAVAL MEDICAL RESEARCH UNIT SAN ANTONIO Disruption of Methicillin-resistant Staphylococcus aureus Biofilms with Enzymatic...fold lower than that needed to thoroughly disrupt biofilms in the current investigation. A previous study of α-amylase applied to S. aureus biofilms...Staphylococcus aureus biofilms. Open Microbiology Journal, 2011. 5: p. 21-31. 36. Wu, J.A., et al., Lysostaphin disrupts Staphylococcus aureus and
Vergara, Alberto; Normanno, Giovanni; Di Ciccio, Pierluigi; Pedonese, Francesca; Nuvoloni, Roberta; Parisi, Antonio; Santagada, Gianfranco; Colagiorgi, Angelo; Zanardi, Emanuela; Ghidini, Sergio; Ianieri, Adriana
The capability to produce biofilm is an important persistence and dissemination mechanism of some foodborne bacteria. This paper investigates the relationship between some molecular characteristics (SCCmec, ST, spa-type, agr-type, cna, sarA, icaA, icaD, clfA, fnbA, fnbB, hla, hlb) of 22 food-related methicillin-resistant Staphylococcus aureus (MRSA) strains and their ability to form biofilm on stainless steel and polystyrene. Five (22.7%, 5/22) strains were able to synthesize biofilm on polystyrene, and one of these (4.5%, 1/22) strains was also able to synthesize biofilm on stainless steel. The largest amount of biofilm was formed on polystyrene by 2 MRSA strains isolated from cows' milk, thus raising concern about the dairy industry. The majority of MRSA biofilm producers carried SCCmec type IVa, suggesting that the presence of SCCmecIVa and/or agr type III could be related to the ability to form biofilm. In conclusion, in order to achieve an acceptable level of food safety, Good Hygiene Practices should be strictly implemented along the food chain to reduce the risk of colonization and dissemination of MRSA biofilm-producing strains in the food industry. © 2017 Institute of Food Technologists®.
Full Text Available Background: Methicillin-resistant Staphylococcus aureus (MRSA has been an important nosocomial pathogen worldwide for more than four decades. Community-acquired MRSA infections, generally occurring in previously healthy persons without recognizable risk factors for health care setting-related MRSA, are emerging as serious clinical and public health concerns. The most frequent of these community-based infections include skin and soft tissue infections and necrotizing pneumonias. A majority of causative community-acquired MRSA (CA-MRSA isolates are associated with genes that encode the virulence factor, Panton-Valentine leukocidin (PVL toxin. Aims & Objectives: To describe six cases of CA-MRSA pneumonia recently admitted to our community hospital in Florida, and discuss the epidemiology, clinical features, and management of these expanding infections. Methods/Study Design: The medical records of six patients with radiographically-confirmed pneumonia and positive sputum cultures for MRSA at the time of hospitalization at the Lawnwood Regional Medical Center and Heart Institute, Fort Pierce, Florida, from December 2006 through January 2007, were retrospectively reviewed. All patients were seen by one of the authors (DO, an infectious diseases consultant. Lawnwood Regional Medical Center is a 341-bed, acute care institution and regional referral center for four counties of Treasure Coast, FL. The hospital institution review board gave permission for this study. Results/Findings: Six patients (5 men, 1 woman with CA-MRSA pneumonia were identified. The mean patient age was 57 years (range, 32-79 years. Three patients had no history of previous hospital admission, while two patients had been last hospitalized two years prior to the study admission. Three elderly patients had known co-morbidities predisposing to pneumonia including carcinoma of the lung (2 patients, and cirrhosis, diabetes mellitus, chronic renal failure, COPD, and cardiomyopathy (1
Hur, Jong-Moon; Yang, Chun-Ho; Han, Seung-Ho; Lee, Sook-Hee; You, Yong-Ouk; Park, Jong-Cheol; Kim, Kang-Ju
Methanol extract and its fractions (CHCl3, n-BuOH and H2O) of the fruit body of Phellinus linteus mushroom were investigated for antibacterial activity against methicillin-resistant Staphylococcus aureus. The n-BuOH fraction showed a good antibacterial activity (MIC, 63-125 microg/ml) against all tested strains.
Starlander, Gustaf; Börjesson, Stefan; Grönlund-Andersson, Ulrika; Tellgren-Roth, Christian; Melhus, Asa
The dog-associated Staphylococcus pseudintermedius is a rare pathogen in humans. Here we describe a cluster of infections caused by the methicillin-resistant S. pseudintermedius clone ST71-J-t02-II-III. It involved four elderly patients at a tertiary hospital. Three patients had wound infections, and the strain had a tendency to cause bullous skin lesions.
An 8-year-old, neutered male Labrador retriever dog with generalized pruritis had a history of recurring atopic dermatitis and superficial pyoderma. Cocci and yeast were found on cytology and methicillin-resistant Staphylococcus pseudintermedius was cultured. A regimen of marbofloxacin, dexamethasone, ketoconazole, and cyclosporine in addition to bathing with 2% chlorhexidine shampoo resulted in marked improvement.
Riley, Matthew C.; Bemis, David A.
We report the first complete genome sequences of three predominant clones (ST68, ST71, and ST84) of methicillin-resistant Staphylococcus pseudintermedius in North America. All strains were isolated from canine infections and have different SCCmec elements and antibiotic resistance gene patterns. PMID:27795289
Duijkeren, van E.; Moleman, M.; Oldruitenborgh-Oosterbaan, M.M.S.; Multem, J.; Troelstra, A.; Fluit, A.C.; Wamel, W.J.B.; Houwers, D.J.; Neeling, de A.J.; Wagenaar, J.A.
At the Veterinary Microbiological Diagnostic Center, the Netherlands, the percentage of methicillin-resistant Staphylococcus aureus (MRSA) isolates found in equine clinical samples increased from 0% in 2002 to 37% in 2008. MRSA of spa-type t064, belonging to MLST ST8 and spa-types t011 and t2123, bo
Krziwanek, Karina; Metz-Gercek, Sigrid; Mittermayer, Helmut
Methicillin-resistant Staphylococcus aureus (MRSA) clonal type ST398 is usually associated with animals. We examined 1,098 confirmed MRSA samples from human patients and found that 21 were MRSA ST398. Most (16) patients were farmers. Increasing prevalence from 1.3% (2006) to 2.5% (2008) shows emergence of MRSA ST398 in humans in Austria.
Walther, Birgit; Monecke, Stefan; Ruscher, Claudia; Friedrich, Alexander W; Ehricht, Ralf; Slickers, Peter; Soba, Alexandra; Wleklinski, Claus-G; Wieler, Lothar H; Lübke-Becker, Antina
Despite the increasing importance of methicillin-resistant Staphylococcus aureus (MRSA) in veterinary medicine, knowledge about the epidemiology of the pathogen in horses is still poor. The phylogenetic relationship of strains of human and equine origins has been addressed before, usually by analyzi
Verstappen, Koen M.; Tulinski, Pawel; Duim, Birgitta; Fluit, Ad C.; Carney, Jennifer; Nes, Van Arie; Wagenaar, Jaap A.
Methicillin-resistant Staphylococcus aureus (MRSA) is an important colonizer in animals and an opportunistic pathogen in humans. In humans, MRSA can cause infections that might be difficult to treat because of antimicrobial resistance. The use of bacteriophages has been suggested as a potential a
Harkins, Catriona P; Pichon, Bruno; Doumith, Michel
BACKGROUND: The spread of drug-resistant bacterial pathogens poses a major threat to global health. It is widely recognised that the widespread use of antibiotics has generated selective pressures that have driven the emergence of resistant strains. Methicillin-resistant Staphylococcus aureus (MR...
Many, Patricia S.
Methicillin-resistant "Staphylococcus aureus" (MRSA) was once thought to be a bacterium causing infections in only hospitalized patients. However, a new strain of MRSA has emerged among healthy individuals who have not had any recent exposure to a hospital or to medical procedures. This new strain is known as "community-associated…
The main goal of this study was to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA), particularly livestock-associated (LA)-MRSA in pigs and pork. Genotypic relatedness of isolates on-farm, at slaughter and retail was assessed. Paired nasal and peri-anal swab samples we...
Gomes, AR; Westh, Henrik; Lancastre, H de
Most methicillin-resistant Staphylococcus aureus (MRSA) isolates identified among blood isolates collected in Denmark between 1957 and 1970 belonged to either phage group III or the closely related 83A complex and had a PSTM antibiotype (resistance to penicillin [P], streptomycin [S], tetracycline...
Battisti, A.; Franco, A.; Merialdi, G.;
A survey for methicillin-resistant Staphylococcus aureus (MRSA) in finishing pig holdings was carried out in Italy in 2008. MRSA isolates were characterised by spa-. SCCmec- and antimicrobial susceptibility typing. A prevalence of 38% (45/118, 95% CI 29.4-46.9%) positive holdings was observed...
Strains of methicillin resistant Staphylococcus aureus (MRSA), a frequent human pathogen, may also be found in the flora of healthy persons and in the environments that they frequent. Strains of MRSA circulating in the community classified as USA 300 are now found not only in the community but also...
Hetem, David J; Westh, Henrik; Boye, Kit;
The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has changed the epidemiology of MRSA infections worldwide. In contrast to hospital-associated MRSA (HA-MRSA), CA-MRSA more frequently affects healthy individuals, both with and without recent healthcare...
Mogensen, Christian Backer; Kjældgaard, Poul; Jensen, Charlotte;
INTRODUCTION: All patients admitted to Danish hospitals are screened for methicillin-resistant Staphylococcus aureus (MRSA) by a questionnaire consisting of 19 questions issued by the Danish Health and Medicines Authority (DHMA). This study aimed to evaluate which of the questions were most useful...
The aim of this thesis was to evaluate the clinical impact of methicillin-resistant Staphylococcus aureus [MRSA] infections on the total burden of disease. A guideline on empirical antimicrobial eradication of MRSA in carriers was developed based on a systematic review of literature. A distinction w
Many, Patricia S.
Methicillin-resistant "Staphylococcus aureus" (MRSA) was once thought to be a bacterium causing infections in only hospitalized patients. However, a new strain of MRSA has emerged among healthy individuals who have not had any recent exposure to a hospital or to medical procedures. This new strain is known as "community-associated…
Larsen, Jesper; Stegger, Marc; Andersen, Paal S.;
We investigated the evolution and epidemiology of a novel live-stock-associated methicillin-resistant Staphylococcus aureus strain, which colonizes and infects urban-dwelling Danes even without a Danish animal reservoir. Genetic evidence suggests both poultry and human adaptation, with poultry meat...
Mogensen, Christian Backer; Kjældgaard, Poul; Jensen, Charlotte
INTRODUCTION: All patients admitted to Danish hospitals are screened for methicillin-resistant Staphylococcus aureus (MRSA) by a questionnaire consisting of 19 questions issued by the Danish Health and Medicines Authority (DHMA). This study aimed to evaluate which of the questions were most useful...
Deurenberg, Ruud H; Nulens, Eric; Valvatne, Havard; Sebastian, Silvie; Driessen, Christel; Craeghs, Jos; De Brauwer, Els; Heising, Bernhard; Kraat, Yvette J; Riebe, Joachim; Stals, Frans S; Trienekens, Thera A; Scheres, Jacques; Friedrich, Alexander W; van Tiel, Frank H; Beisser, Patrick S; Stobberingh, Ellen E
Because the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) differs among the 3 countries forming the Euregio Meuse-Rhin (EMR) region (Belgium, Germany, and the Netherlands), cross-border healthcare requires information about the spread of MRSA in the EMR. We investigated the emerge
Siddiqui, Sorath Noorani; Zafar, Saemah Nuzhat
Methicillin-resistant Staphylococcus aureus is one of the toughest organisms to treat, especially in cases where intraocular surgery is contemplated, because the risks are aggravated. Conjunctival swab culture and sensitivity tests are significant when there is history of recent hospitalization. In this report, an infant with successful cataract surgery after elimination of the organism is presented.
Koeck, Robin; Mellmann, Alexander; Schaumburg, Frieder; Friedrich, Alexander W.; Kipp, Frank; Becker, Karsten
Background: For decades, methicillin-resistant Staphylococcus aureus (MRSA) has been a major cause of infection in hospitals and nursing homes (health care-associated MRSA, HA-MRSA). Beginning in the late 1990s, many countries have also experienced a rising incidence of MRSA infection outside of the
Wassenberg, M. W. M.; Bootsma, M. C. J.; Troelstra, A.; Kluytmans, J. A. J. W.; Bonten, M. J. M.
P>We quantified nosocomial transmission rates of sequence type (ST) 398 methicillin-resistant Staphylococcus aureus (MRSA) (an emerging livestock-associated MRSA clone) and non-ST398 MRSA isolates in patients hospitalized without infection control measures in 51 Dutch hospitals. Identification of 17
Hetem, D.J.; Westh, H.; Boye, K.; Jarlov, J.O.; Bonten, M.J.M.; Bootsma, M.C.J.
Objectives The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has changed the epidemiology of MRSA infections worldwide. In contrast to hospital-associated MRSA (HA-MRSA), CA-MRSA more frequently affects healthy individuals, both with and without recent healt
Verstappen, Koen M; Tulinski, Pawel; Duim, Birgitta; Fluit, Ad C; Carney, Jennifer; van Nes, Arie; Wagenaar, Jaap A
UNLABELLED: Methicillin-resistant Staphylococcus aureus (MRSA) is an important colonizer in animals and an opportunistic pathogen in humans. In humans, MRSA can cause infections that might be difficult to treat because of antimicrobial resistance. The use of bacteriophages has been suggested as a
Verstappen, Koen M.; Tulinski, Pawel; Duim, Birgitta; Fluit, Ad C.; Carney, Jennifer; Nes, Van Arie; Wagenaar, Jaap A.
Methicillin-resistant Staphylococcus aureus (MRSA) is an important colonizer in animals and an opportunistic pathogen in humans. In humans, MRSA can cause infections that might be difficult to treat because of antimicrobial resistance. The use of bacteriophages has been suggested as a potential
M. Pujol (Miquel); C. Pena; R. Pallares (Roman); J. Ayats (Josefina); J. Ariza (Javier); F. Gudiol (Francesc)
textabstractIn a prospective surveillance study (February 1990–December 1991) performed at a 1000-bed teaching hospital to identify risk factors for nosocomial methicillin-resistantStaphylococcus aureus (MRSA) bacteremia, 309 patients were found to be colonized (n=103; 33 %) or infected (n=206; 67 %
Schaumburg, Frieder; Koeck, Robin; Mellmann, Alexander; Richter, Laura; Hasenberg, Felicitas; Kriegeskorte, Andre; Friedrich, Alexander W.; Gatermann, Soeren; von Eiff, Christof; Becker, Karsten; Peters, Georg
Methicillin-resistant Staphylococcus aureus (MRSA) originated from the health care setting but is now emerging in communities without health care contact (CA-MRSA) or in livestock (LA-MRSA). The impact on the whole MRSA population was assessed in a German prospective multicenter study. Thirty-three
H.S.M. Ammerlaan; J.A.J.W. Kluytmans; H. Berkhout; A. Buiting; E.I.G.B. de Brauwer; P.J. van den Broek; P. van Gelderen; S.C.A.P. Leenders; A. Ott; C.J.J. Richter; L. Spanjaard; I.J.B. Spijkerman; F.H. van Tiel; G.P. Voorn; M.W.H. Wulf; J. van Zeijl; A. Troelstra; M.J.M. Bonten
Background: We evaluated the effectiveness of eradication of methicillin-resistant Staphylococcus aureus (MRSA) carriage in the Netherlands after the introduction of a guideline in 2006. The guideline distinguishes complicated (defined as the presence of MRSA infection, skin lesions, foreign-body ma
Hsu, Li-Yang; Harris, Simon R.; Chlebowicz, Monika A.; Lindsay, Jodi A.; Koh, Tse-Hsien; Krishnan, Prabha; Tan, Thean-Yen; Hon, Pei-Yun; Grubb, Warren B.; Bentley, Stephen D.; Parkhill, Julian; Peacock, Sharon J.; Holden, Matthew T. G.
Background: In the past decade, several countries have seen gradual replacement of endemic multi-resistant healthcare-associated methicillin-resistant Staphylococcus aureus (MRSA) with clones that are more susceptible to antibiotic treatment. One example is Singapore, where MRSA ST239, the dominant
Moodley, Arshnee; Damborg, Peter Panduro; Nielsen, Søren Saxmose
Staphylococcus pseudintermedius is a commensal and a common opportunistic pathogen causing mainly infections of the integumentary system in dogs. The recent emergence of multidrug-resistant S. pseudintermedius isolates, in particular methicillin-resistant strains (MRSP) is a threat to small anima...
Hartmeyer, Gitte Nyvang; Gahrn-Hansen, Bente; Skov, Robert L
Abstract Carriage of pig-associated methicillin-resistant Staphylococcus aureus (MRSA) is known to occur in pig farmers. Zoonotic lineages of MRSA have been considered of low virulence and with limited capacity for inter-human spread. We present a case of family transmission of pig-associated MRS...
Walther, Birgit; Monecke, Stefan; Ruscher, Claudia; Friedrich, Alexander W; Ehricht, Ralf; Slickers, Peter; Soba, Alexandra; Wleklinski, Claus-G; Wieler, Lothar H; Lübke-Becker, Antina
Despite the increasing importance of methicillin-resistant Staphylococcus aureus (MRSA) in veterinary medicine, knowledge about the epidemiology of the pathogen in horses is still poor. The phylogenetic relationship of strains of human and equine origins has been addressed before, usually by
Carmen S Arriola
Full Text Available We report the first detection of methicillin-resistant Staphylococcus aureus isolates in pigs in Peru. The isolates belong to a livestock-associated lineage previously reported in North America and Europe, CC398, and a highly virulent USA300-like ST8-IV variant, which is the predominant community-associated lineage in Latin America.
Hanley, Patrick W; Barnhart, Kirstin F; Abee, Christian R; Lambeth, Susan P; Weese, J Scott
Methicillin-resistant Staphylococcus aureus (MRSA) infection in humans and animals is concerning. In 2012, our evaluation of a captive chimpanzee colony in Texas revealed MRSA prevalence of 69%. Animal care staff should be aware of possible zoonotic MRSA transmission resulting from high prevalence among captive chimpanzees.
An 8-year-old, neutered male Labrador retriever dog with generalized pruritis had a history of recurring atopic dermatitis and superficial pyoderma. Cocci and yeast were found on cytology and methicillin-resistant Staphylococcus pseudintermedius was cultured. A regimen of marbofloxacin, dexamethasone, ketoconazole, and cyclosporine in addition to bathing with 2% chlorhexidine shampoo resulted in marked improvement. PMID:25392557
The aim of this thesis was to evaluate the clinical impact of methicillin-resistant Staphylococcus aureus [MRSA] infections on the total burden of disease. A guideline on empirical antimicrobial eradication of MRSA in carriers was developed based on a systematic review of literature. A distinction
Bootsma, M.C.; Diekmann, O.; Bonten, M.J.M.
Control of nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) has been unsuccessful in most countries. Yet, some countries have maintained low endemic levels by implementing nationwide MRSA-specific infection control measures, such as ‘‘search & destroy’’ (S&D). These
S. Petti; N. Kakisina; C.M.C. Volgenant; G.A. Messano; E. Barbato; C. Passariello; J.J. de Soet
We assessed methicillin-resistant Staphylococcus aureus (MRSA) carriage rate among dental students from an Italian university. A total of 157 subjects participated (67 preclinical students and 90 clinical students); samples were collected from the nose, mouth, and skin. Five preclinical students and
Argudin, Maria Angeles; Lauzat, Birgit; Kraushaar, Britta;
Livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has emerged in animal production worldwide. Most LA-MRSA in Europe belong to the clonal complex (CC)398. The reason for the LA-MRSA emergence is not fully understood. Besides antimicrobial agents used for therapy, other su...
Full Text Available Antibacterial activity of organic and aqueous extracts of Acacia aroma was evaluated against methicillin-resistant Staphylococcus aureus (MRSA, methicillin sensitive Staphylococcus aureus (MSSA and methicillin-resistant Staphylococcus epidermidis. Inhibition of bacterial growth was determined using agar diffusion and bioautographic methods. Among all assayed organic extracts only ethanolic and ethyl acetate extracts presented highest activities against all tested Staphylococcus strains with minimal inhibitory concentration (MIC values ranging from 2.5 to 10 mg/ml and from 2.5 to 5 mg/ml respectively. The aqueous extracts show little antibacterial activity against Staphylococcus strains. The bioautography assay demonstrated well-defined growth inhibition zones against S. aureus in correspondence with flavonoids and saponins. A. aroma would be an interesting topic for further study and possibly for an alternative treatment for skin infections.
Nubel, U.; Roumagnac, P.; Feldkamp, M.;
A small number of clonal lineages dominates the global population structure of methicillin-resistant Staphylococcus aureus (MRSA), resulting in the concept that MRSA has emerged on a few occasions after penicillinase-stable beta-lactam antibiotics were introduced to clinical practice, followed...... of mutational steps that define geographically associated clades. These clades are not concordant with previously described groupings based on staphylococcal protein A gene (spa) typing. By mapping the number of independent imports of the staphylococcal cassette chromosome methicillin-resistance island, we also...
The presence of antibiotic resistant bacteria and antibiotic resistance genes in rural sewage treatment plants are not well reported in the literature. The aim of the present study was to study the frequency occurrence of Methicillin Resistant Staphylococcus aureus (MRSA) in a rural sewage treatment plant. This study was conducted using raw sewage as well as treated sewage from a small town sewage treatment plant in rural southeast Louisiana of USA. Results showed the presence of MRSA consistently in both raw and treated sewage. The presence of mecA gene responsible for methicillin resistance was confirmed in the raw and treated sewage water samples. Copyright © 2017 Elsevier Ltd. All rights reserved.
Brief report Longitudinal characterization of Acinetobacter baumannii-calcoaceticus complex, Klebsiella pneumoniae , and methicillin-resistant...resistant Acinetobacter baumannii-calcoaceticus complex Klebsiella pneumoniae Methicillin-resistant Staphylococcus aureus MRSA Drug-resistant...Acinetobacter baumannii-calcoaceticus complex, Klebsiella pneumoniae , and methicillin- resistant Staphylococcus aureus colonize and infect combat casualties
Duim, Birgitta; Verstappen, Koen M.; Broens, E.M.; Laarhoven, Laura M.; Duijkeren, Van Engeline; Hordijk, Joost; Heus, De Phebe; Spaninks, Mirlin; Timmerman, Arjen J.; Wagenaar, J.A.
Methicillin-resistant Staphylococcus pseudintermedius (MRSP), which is often multidrug resistant (MDR), has recently emerged as a threat to canine health worldwide. Knowledge of the temporal distribution of specific MRSP lineages, their antimicrobial resistance phenotypes, and their association w
Moodley, Arshnee; Riley, Matthew C; Kania, Stephen A; Guardabassi, Luca
We report the first genome sequence of the methicillin-resistant Staphylococcus pseudintermedius (MRSP) strain E140, isolated from a canine bite wound infection in Denmark. This strain represents the dominant clonal lineage associated with canine MRSP infections in Europe.
Kolenda, Camille; Dupieux, Céline; Decousser, Jean-Winoc; Larsen, Anders Rhod; Pichon, Bruno; Holmes, Mark; Bès, Michèle; Teale, Christopher; Dickson, Elizabeth; Hill, Robert; Skov, Robert; Kearns, Angela; Laurent, Frédéric
Methicillin-resistance in Staphylococcus aureus is classically mediated by the mecA gene carried on a mobile genetic element, called staphylococcal cassette chromosome mec (SCCmec).…. Copyright © 2017 American Society for Microbiology.
Worldwide, reports document the increasing frequency of methicillin resistant Staphylococcus aureus (MRSA) infections. Other human pathogens are recognized as unresponsive to antibiotics of last resort. These previously treatable infections now account for increased numbers of human disease and de...
Tsironi Evangelia E
Full Text Available Abstract Background Methicillin-resistant Staphylococcus aureus is a serious cause of morbidity and mortality in hospital environment, but also, lately, in the community. This case report is, to our knowledge, the first detailed description of a community-associated methicillin-resistant S. aureus ST80 orbital cellulitis in a previously healthy neonate. Possible predisposing factors of microbial acquisition and treatment selection are also discussed. Case presentation A 28-day-old Caucasian boy was referred to our hospital with the diagnosis of right orbital cellulitis. His symptoms included right eye proptosis, periocular edema and redness. Empirical therapy of intravenous daptomycin, rifampin and ceftriaxone was initiated. The culture of pus yielded a methicillin-resistant S. aureus isolate and the molecular analysis revealed that it was a Panton-Valentine leukocidine-positive ST80 strain. The combination antimicrobial therapy was continued for 42days and the infection was successfully controlled. Conclusions Clinicians should be aware that young infants, even without any predisposing condition, are susceptible to orbital cellulitis caused by community-associated methicillin-resistant S. aureus. Prompt initiation of the appropriate empirical therapy, according to the local epidemiology, should successfully address the infection, preventing ocular and systemic complications.
B A Fomda
Full Text Available Background: Nasal colonisation with community acquired methicillin resistant Staphylococcus aureus (CA-MRSA is being increasingly reported, especially in places where people are in close contact and where hygiene is compromised. The aim of this study was to find out prevalence of methicillin resistant S.aureus (MRSA colonising anterior nares of healthy subjects. Materials and Methods: Nasal swabs of healthy subjects were collected aseptically and cultured using standard microbiological protocols. Antibiotic susceptibility was done by Kirby-Bauer disc diffusion method according to CLSI guidelines. Methicillin resistance was detected by cefoxitin disc diffusion method and confirmed by minimum inhibitory concentration (MIC and amplification of mecA gene by PCR. Strain typing of MRSA strains was done by PFGE. Results: Out of 820 samples, S.aureus was isolated from 229 (27.92% subjects. Of the 229 isolates, 15 were methicillin resistant. All S. aureus isolates were susceptible to vancomycin. Nasal carriage of MRSA was found to be 1.83% among healthy population. The isolates were found to be polyclonal by PFGE analysis. Conclusion: High prevalence of MRSA is a cause of concern and strategies to interrupt transmission should be implemented.
Bartels, Mette Damkjær; Boye, Kit; Larsen, Anders Rhod
In Copenhagen, methicillin-resistant Staphylococcus aureus (MRSA) accounted for <15 isolates per year during 1980-2002. However, since 2003 an epidemic increase has been observed, with 33 MRSA cases in 2003 and 110 in 2004. We analyzed these 143 cases epidemiologically and characterized isolates ...... and soft tissue infections dominated. CO-MRSA with diverse genetic backgrounds is rapidly emerging in a low MRSA prevalence area. Udgivelsesdato: October...
Bartels, Mette Damkjaer; Boye, Kit; Rhod Larsen, Anders
In Copenhagen, methicillin-resistant Staphylococcus aureus (MRSA) accounted for <15 isolates per year during 1980-2002. However, since 2003 an epidemic increase has been observed, with 33 MRSA cases in 2003 and 110 in 2004. We analyzed these 143 cases epidemiologically and characterized isolates ...... and soft tissue infections dominated. CO-MRSA with diverse genetic backgrounds is rapidly emerging in a low MRSA prevalence area....
Poovelikunnel, Toney Thomas
Methicillin-resistant Staphylococcus aureus (MRSA) is an endemic pathogen of public health concern in Ireland, as in many other health systems. For the nasal clearance of MRSA, the site that is often colonised in humans, the antibiotic mupirocin remains one of the most successful topical antibiotics to date. However, increasing bacterial resistance to mupirocin and limited effective alternate antibiotic options necessitate the need for unconventional approaches to eradicate nasal MRSA. Coloni...
Nemeghaire, Stéphanie; Argudín, M Angeles; Haesebrouck, Freddy; Butaye, Patrick
Background: Staphylococcus aureus is a common bacterium usually found on skin and mucous membranes of warm blooded animals. Resistance in S. aureus has been increasingly reported though depending on the clonal lineage. Indeed, while hospital acquired (HA)-methicillin resistant S. aureus (MRSA) are typically multi-resistant, community associated (CA)-MRSA are by large more susceptible to many antibiotics. Although S. aureus isolated from animals are often susceptible to most antibiotics, multi...
Caelli, M; Porteous, J; Carson, C F; Heller, R; Riley, T V
The combination of a 4% tea tree oil nasal ointment and 5% tea tree oil body wash was compared with a standard 2% mupirocin nasal ointment and triclosan body wash for the eradication of methicillin-resistant Staphylococcus aureus carriage. The tea tree oil combination appeared to perform better than the standard combination, although the difference was not statistically significant due to the small number of patients.
Full Text Available Of 259 college students in northern Taiwan surveyed, nasal carriage rate of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA was 22.4% and 1.54%, respectively and no significant difference was found between athlete students and non-athlete students. Three of four MRSA isolates belonged to sequence type 59, the endemic community clone.
Marcelle Aquino Rabelo
Full Text Available INTRODUCTION: Staphylococcus spp. is an important healthcare-associated pathogen and the identification of methicillin-resistant strains in samples of colonization may provide data to assist in the antimicrobial therapy success. OBJECTIVES: To determine the occurrence of colonization by methicillin-resistant Staphylococcus spp. (MRS, through the detection of the mecA gene and to evaluate different phenotypic methods for the presumptive detection of methicillin resistance in samples of the anterior nasal cavity and hands of the health care personnel of a university hospital in the state of Pernambuco, Brazil. METHODS: We selected the 28 isolates of Staphylococcus spp., which showed an intermediate or resistant phenotypic profile for oxacillin, detected by the Kirby Bauer technique. The methods used were disk-diffusion tests for cefoxitin, minimal inhibitory concentration by E-test for oxacillin, screening for oxacillin resistance and mecA gene detection by polymerase chain reaction (PCR. RESULTS: About the phenotypic methods utilized, only the E-test of oxacillin did not show a statistically significant difference in relation to PCR for the mecA gene detection, considered the gold standard. CONCLUSION: The E-test of oxacillin was the best of the phenotypic methods utilized. It is necessary to correctly detect MRS in healthy individuals, because they can act as carriers and can therefore be a potential source of microorganisms involved in hospital infections.
Full Text Available Objectives: The aim of this study was to evaluate the distribution of Staphylococcus species in bloodstream infections and to assess their susceptibility to methicillin. Material and Methods: Between January 1st 2008 - December 31st 2010, 7424 blood culture sets were submitted to the Laboratory Department of the Hospital for Clinical Infectious Diseases in Cluj-Napoca, Romania. The blood cultures were performed using BacT/Alert until January 2010 and BacT/Alert 3D automated system (bioMérieux after that date. The blood culture bottles were incubated at 37°C in a continuously monitoring system for up to 7 days. The strain identifications were performed by conventional methods, ApiStaph galleries and Vitek 2 Compact system. Susceptibility to methicillin was determined by disk diffusion method with cefoxitin disk and by using Vitek 2 Compact system. Results: From the total number of performed blood cultures, 568 were positive with Staphylococcus species. From 168 bacteriemic episodes 103 were with Staphylococcus aureus. Among 65 coagulase-negative staphylococci isolates, Staphylococcus epidermidis was the most frequently isolated species (34, followed by Staphylococcus hominis (15, Staphylococcus haemolyticus (8, Staphylococcus saprophyticus (3, Staphylococcus cohnii (1, Staphylococcus auricularis (1, and 3 strains that were not identified at species level. Methicillin resistance was encountered in 53.40% of Staphylococcus aureus strains and in 80% of coagulase-negative staphylococci. Conclusions: An important percentage of blood cultures were contaminated with Staphylococcus species. The main species identified in true bacteriemia cases were Staphylococcus aureus and Staphylococcus epidermidis. The percentage of methicillin-resistance, proved to be high not only for coagulase-negative staphylococci but also for Staphylococcus aureus.
Full Text Available Although conventional antibiotic susceptibility tests are most commonly performed for methicillin-resistant Staphylococcus aureus (MRSA, the results of these phenotypic tests are dependent on the standardization of the culture conditions. The aim of the study was to evaluate the conventional phenotypic screening tests in comparison to the mecA gene polymerase chain reaction (PCR. One hundred and two clinical isolates of MRSA identified by the oxacillin disk diffusion were subjected to PCR for the mecA gene and by the cefoxitin disk diffusion test and culture on oxacillin screen agar, mannitol salt agar, and methicillin-resistant Staphylococcus aureus Agar (MeReSA selective medium, for MRSA. Although all 102 isolates were resistant in oxacillin and cefoxitin disk diffusion, 92 (90.1% isolates were positive for the mecA gene. The sensitivities of the mannitol salt agar, MeReSA agar, and oxacillin screen agar were 89.13, 97.82, and 98.91%, respectively. The oxacillin screen agar may be recommended for confirming methicillin resistance in the disk diffusion test in resource-poor settings, where molecular methods are not available.
Full Text Available Background & Aims of the Study: Methicillin-resistant staphylococcus aureus (MRSA is considered as a major pathogen in public health concern. The objectives of this study were to firstly determine antibiotic sensitivity among Staphylococcus aureus isolated from traditional Iranian white cheese during 2015 from Hamedan province of Iran; and secondly to estimate the presence of methicillin-resistant S. aureus. Materials &Methods: This cross-sectional study was done by collecting 120 Iranian white cheeses (traditional and industrial which were available in different markets; and tested for the presence of S. aureus by culture methods. The obtained isolates were subjected to disc diffusion antimicrobial susceptibility tests followed by PCR detection of the mecA gene. Results: Out of 120 examined cheese samples, 19 samples (31.67% were contaminated with S. aureus. The highest rate of antibiotic resistance was observed for penicillin, as all of the 19 isolates (100% were found to be resistant to this antibiotic using disk diffusion method. Three out of 19 S. aureus isolates (15.7% were phenotypically resistant to methicillin (disk diffusion, while 4 (21.05% of them were genotypically confirmed as MRSA strains. Furthermore, none of the isolates were found resistant to vancomycin. Conclusion: The results of the study confirm the presence of methicillin resistant strains of S. aureus in Iranian white cheese. It should be considered to constitute a potential health risk for consumers, suggesting usage of more stringent hygiene measures.
Oyetunji I. Ajoke
Full Text Available This study investigated the prevalence of Methicillin-resistant Staphylococcus aureus (MRSA from the nasal swabs of healthy community individual volunteers in Jos South, Nigeria and its susceptibility pattern to seven other antibiotics. Standard procedures were employed for isolation, screening, and susceptibility testing. The result of this study reveal that 98 (49 % S. aureus were isolated from 200 nasal swab samples collected. The prevalence rate for male and female group was 48 % and 50 % respectively. Sixty two isolates (63.3 % were found to be methicillin resistant. The MRSA isolated were highly resistant to Ampicillin (88.7 %, Amoxicillin (85.5 %, Tetracycline (80.6 %, Cotrimoxazole (80.6 % but had low resistance to Erythromycin (35.5%. The MRSA isolated showed high susceptibility to Ofloxacin (98.4 % and Gentamicin (83.9 %. While 55 (88.7 % of the MRSA isolated showed multidrug resistance and only 3 (4.8 % were susceptible to all other tested antibiotics.
Aung, Kyaw Thu; Hsu, Li Yang; Koh, Tse Hsien; Hapuarachchi, Hapuarachchige Chanditha; Chau, Man Ling; Gutiérrez, Ramona Alikiiteaga; Ng, Lee Ching
We characterised 227 Staphylococcus aureus isolates from retail food and food handlers' gloves samples obtained through food surveillance and risk assessment studies between 2011 and 2014. Of 227 isolates, five (2.2%) were methicillin-resistant and belonged to sequence types ST80 (n = 3) and ST6 (n = 2). All five isolates belonged to SCCmec type IV, were Panton-Valentine leukocidin (pvl)-negative and staphylococcal enterotoxin genes-positive. Resistance to azithromycin was found in ST80 isolates, in addition to resistance to beta-lactams. Our finding of two clinically relevant methicillin-resistant S. aureus (MRSA) strains (ST80 and ST6) in ready-to-eat food and food contact surfaces at retail in Singapore suggests food and food contact surfaces as potential environmental sources of MRSA in the community.
Full Text Available In this work there was evaluated the method of detection of methicillin resistant Staphylococcus aureus (MRSA by using two molecular and three phenotypic tests in investigation procedure of 70 strains of S.aureus isolated from animals. Recent findings of the new mecA homologue, mecALGA251, minimise the significance of mecA gene presence detection as a confirmation method of methicillin resistant Staphylococcus aureus identification. For this reason, along with multiplex PCR set of primers(165rDNK, nuc, mecA for detection mecA gene, there was also used multiplex PCR set of primers (spa, mecA, pvl, mecALGA251 for differentiation mecALGA251 from mecA, with simultaneous detection of luk-PV and spa gene fragments. In all 70 investigated isolates there was detected the presence of specific 16 SrDNK fragment and nuc gene which encodes a thermostable S. aureus nuclease, while in 5 out of 70 S. aureus isolates, there was proven mecA gene presence using two multiplex PCR tests. In the investigated strains there was determined neither mecC (mecALGA251gene presence, nor Panton Valentine Leukocidin encoding gene. By application cefoxitin disk-diffusion, latex-agglutination and two multiplex PCR tests, the identical results in identification 5 methicillin resistant out of 70 investigated S. aureus strains were obtained. In our investigation there was determined a complete correlation between the results of phenotypic and genotypic identification of methicillin resistant S. aureus. [Projekat Ministarstva nauke Republike Srbije, br. TR 31079
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.
Garnier, Fabien; Tristan, Anne; François, Bruno; Etienne, Jerome; Delage-Corre, Manuella; Martin, Christian; Liassine, Nadia; Wannet, Wim; Denis, François; Ploy, Marie-Cécile
Necrotizing pneumonia caused by Staphylococcus aureus strains carrying the Panton-Valentin leukocidin gene is a newly described disease entity. We report a new fatal case of necrotizing pneumonia. An S. aureus strain with an agr1 allele and of a new sequence type 377 was recovered, representing a ne
Ishihara, Kanako; Shimokubo, Natsumi; Sakagami, Akie; Ueno, Hiroshi; Muramatsu, Yasukazu; Kadosawa, Tsuyoshi; Yanagisawa, Chie; Hanaki, Hideaki; Nakajima, Chie; Suzuki, Yasuhiko; Tamura, Yutaka
Recently, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) have been increasingly isolated from veterinarians and companion animals. With a view to preventing the spread of MRSA and MRSP, we evaluated the occurrence and molecular characteristics of each in a veterinary college. MRSA and MRSP were isolated from nasal samples from veterinarians, staff members, and veterinary students affiliated with a veterinary hospital. Using stepwise logistic regression, we identified two factors associated with MRSA carriage: (i) contact with an identified animal MRSA case (odds ratio [OR], 6.9; 95% confidence interval [95% CI], 2.2 to 21.6) and (ii) being an employee (OR, 6.2; 95% CI, 2.0 to 19.4). The majority of MRSA isolates obtained from individuals affiliated with the veterinary hospital and dog patients harbored spa type t002 and a type II staphylococcal cassette chromosome mec (SCCmec), similar to the hospital-acquired MRSA isolates in Japan. MRSA isolates harboring spa type t008 and a type IV SCCmec were obtained from one veterinarian on three different sampling occasions and also from dog patients. MRSA carriers can also be a source of MRSA infection in animals. The majority of MRSP isolates (85.2%) carried hybrid SCCmec type II-III, and almost all the remaining MRSP isolates (11.1%) carried SCCmec type V. MRSA and MRSP were also isolated from environmental samples collected from the veterinary hospital (5.1% and 6.4%, respectively). The application of certain disinfection procedures is important for the prevention of nosocomial infection, and MRSA and MRSP infection control strategies should be adopted in veterinary medical practice.
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.
Traversa, A; Gariano, G R; Gallina, S; Bianchi, D M; Orusa, R; Domenis, L; Cavallerio, P; Fossati, L; Serra, R; Decastelli, L
Following the detection of methicillin-resistant Staphylococcus aureus (MRSA) ST398 in food-producing animals, both livestock and wildlife, and derived products, are considered potential sources of MRSA in humans. There is a paucity of data on MRSA in foods in Italy, and the data regarding wild animals are particularly scarce. A total of 2162 food samples collected during official monitoring activities in 2008 were analyzed for the detection of S. aureus. Also, samples from 1365 wild animals collected by the National Reference Center for Wild Animal Diseases in 2003-2009 were subjected to anatomopathological examination. S. aureus isolates were processed for phenotypic and molecular methicillin resistance determinations. S. aureus was found in 2.0% of wild animal carcasses and in 3.2% of wild boar lymph nodes: none showed methicillin resistance. The prevalence of S. aureus in food was 17.1%. Two MRSA strains, both from bulk tank milk (prevalence 0.77%) were isolated: the strains were resistant to tetracycline, had spa-type t899, and were negative for the Panton-Valentine leukocidin gene. The low prevalence of MRSA suggests that the risk of transmission to humans via food is limited. However, attention should be paid to the cattle food chain, which may be a potential route of transmission of LA-MRSA.
Durão, D; Fernandes, AP; Marum, S; Marcelino, P; Mourão, L
As pericardites bacterianas, apesar da sua baixa incidência e das terapêuticas actuais, apresentam um prognóstico desfavorável, sobretudo quando causadas por Staphylococcus aureus meticilino resistente (MRSA). O Tamponamento cardíaco é uma complicação potencialmente letal nos doentes com pericardites por este agente. Numa Unidade de Cuidados Intensivos, para além da imunossupressão, constituem factores predisponentes para este tipo de infecção, a elevada taxa ...
Christiansen, Mette Theilgaard
Staphylococcus aureus is an opportunistic pathogen that colonizes the nares and skin surfaces of several animal species, including man. S. aureus can cause a wide variety of infections ranging from superficial soft tissue and skin infections to severe and deadly systemic infections. Traditionally S...... for LA-MRSA ST398 survival on porcine skin and nasal epithelium ex vivo were identified. These genes could represent targets for de-colonization, which could help prevent further spread and adaption of LA-MRSA ST398. Manuscript III describes the construction of the S. aureus VirulenceFinder database....... The database can be applied for identification of virulence genes in S. aureus using whole genome 5 sequence data. The S. aureus VirulenceFinder will be part of the tool package generated for the Centre for Genomic Epidemiology (CGE) (www.genomicepidemiology.org)....
Ruzauskas, M; Couto, N; Belas, A; Klimiene, I; Siugzdiniene, R; Pomba, C
During 2011, 160 nasal samples were taken from pigs on 8 different farms in Lithuania. Four methicillin-resistant Staphylococcus aureus (MRSA) isolates were obtained. The isolates were ST398, spa type t011 and SCCmec V and none carried the lukF/lukS genes. Strains were resistant to tetracycline, attributed to tetK and tetM genes, and to erythromycin owing to the ermB gene. One MRSA strain was resistant to trimethoprim/sulfamethoxazole and carried the dfrK gene. This is the first report on the presence and characteristics of livestock-associated MRSA isolated from pigs in Lithuania.
Furukawa, Kenei; Tsutsumi, Jun; Takayama, Sumio; Mashiko, Hiroshi; Shiba, Hiroaki; Yanaga, Katsuhiko
A 68-year-old man underwent total gastrectomy and splenectomy for adenocarcinoma and low anterior resection for carcinoma in tubulo-villous adenoma of the rectum. Broad-spectrum antibiotics were administered for postoperative pancreatic fistula. Methicillin-resistant Staphylococcus aureus enteritis occurred on the 50th postoperative day and cecal perforation followed. The patient underwent construction of cecostomy with peritoneal drainage, and vancomycin was administered orally and per cecostomy for 2 weeks. The patient recovered well and was discharged at 35 days after re-operation in good general condition.
Furukawa, Kenei; Tsutsumi, Jun; Takayama, Sumio; Mashiko, Hiroshi; Shiba, Hiroaki; Yanaga, Katsuhiko
A 68-year-old man underwent total gastrectomy and splenectomy for adenocarcinoma and low anterior resection for carcinoma in tubulo-villous adenoma of the rectum. Broad-spectrum antibiotics were administered for postoperative pancreatic fistula. Methicillin-resistant Staphylococcus aureus enteritis occurred on the 50th postoperative day and cecal perforation followed. The patient underwent construction of cecostomy with peritoneal drainage, and vancomycin was administered orally and per cecostomy for 2 weeks. The patient recovered well and was discharged at 35 days after re-operation in good general condition. PMID:25785319
Nimmo, Graeme R.; Schooneveldt, Jacqueline; O'Kane, Gabrielle; McCall, Brad; Vickery, Alison
Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) susceptible to gentamicin has been reported in a number of countries in the 1990s. To study the acquisition of gentamicin-sensitive MRSA (GS-MRSA) in southeast Queensland and the relatedness of GS-MRSA to other strains of MRSA, 35 cases of infection due to GS-MRSA from October 1997 through September 1998 were examined retrospectively to determine the mode of acquisition and risk factors for MRSA acquisition. Thirty-one isol...
Full Text Available Prostatic abscesses are usually related to gram-negative bacilli. However, methicillin-resistant Staphylococcus aureus (MRSA has emerged as a substantial cause of prostatic abscesses in recent years. Herein, we report the case of a 31-year-old man with a history of orthotopic liver transplantation 10 years ago who presented with acute onset dysuria and abdominal pain and was diagnosed with a MRSA prostatic abscess. To our knowledge, this is the first case describing a prostatic abscess in a liver transplant recipient and the first reporting MRSA as the causative organism of a prostatic abscess in a solid organ transplant recipient.
Hansen, Julie Elvekjær; Rhod Larsen, Anders; Skov, Robert Leo
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) clonal complex (CC) 398 is widespread in the Danish pig production with around 90% of herds being positive. Since 2009, cases of CC398 LA-MRSA infections in Danish mink farmers have been observed. The objective of the study...... slaughter offal is used for mink feed. The spa-types, the high prevalence of LA-MRSA on paws and in pharynx, and its detection in feed samples, suggest feed as a possible source of LA-MRSA in mink....
Saphyakhajon, Phisit; Joshi, Avni Y; Huskins, W Charles; Henry, Nancy K; Boyce, Thomas G
The bacterial agents causing bone and joint infections have been changing. Currently, methicillin-resistant Staphylococcus aureus (MRSA) and Kingella kingae are emerging pathogens. For treatment of MRSA infections, clindamycin, vancomycin, and linezolid are commonly prescribed antibiotics. Kingella are sensitive to most penicillins and cephalosporins. Because MRSA osteoarticular infections tend to be severe, longer periods of antibiotic treatment with more frequent monitoring of inflammatory markers are sometimes required to obtain a complete cure with no residual complications. To assist management, we have included a clinical decision tree with antibiotic treatment protocols.
Cavaco, Lina; Hasman, Henrik; Aarestrup, Frank Møller
This study was conducted to determine the occurrence of zinc and copper resistances in methicillin-resistant Staphylococcus aureus (MRSA) from swine and veal calves in a global strain collection.The test population consisted of 476 porcine MRSA isolates from ten European countries, 18 porcine MRSA...... isolates from Canada and seven MRSA from China, 92 MRSA and 60 methicillin-susceptible S. aureus (MSSA) isolates from veal calves in the Netherlands and 88 porcine MSSA isolates from four European countries. Most porcine MRSA (n=454) and all bovine MRSA belonged to clonal complex (CC) 398 whereas 37...
Weaver, Alan J; Shepard, Joyce B; Wilkinson, Royce A; Watkins, Robert L; Walton, Sarah K; Radke, Amanda R; Wright, Thomas J; Awel, Milat B; Cooper, Catherine; Erikson, Elizabeth; Labib, Mohamed E; Voyich, Jovanka M; Teintze, Martin
This study investigated the potential antibacterial activity of three series of compounds synthesized from 12 linear and branched polyamines with 2-8 amino groups, which were substituted to produce the corresponding guanides, biguanides, or phenylguanides, against Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Antibacterial activity was measured for each compound by determining the minimum inhibitory concentration against the bacteria, and the toxicity towards mammalian cells was determined. The most effective compound, THAM trisphenylguanide, was studied in time-to-kill and cytoplasmic leakage assays against methicillin-resistant Staphylococcus aureus (MRSA, USA300) in comparison to chlorhexidine. Preliminary toxicity and MRSA challenge studies in mice were also conducted on this compound. THAM trisphenylguanide showed significant antibacterial activity (MIC ∼1 mg/L) and selectivity against MRSA relative to all the other bacteria examined. In time-to-kill assays it showed increased antimicrobial activity against MRSA versus chlorhexidine. It induced leakage of cytoplasmic content at concentrations that did not reduce cell viability, suggesting the mechanism of action may involve membrane disruption. Using an intraperitoneal mouse model of invasive MRSA disease, THAM trisphenylguanide reduced bacterial burden locally and in deeper tissues. This study has identified a novel guanide compound with selective microbicidal activity against Staphylococcus aureus, including a methicillin-resistant (MRSA) strain.
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA continues to be a major problem, causing severe and intractable infections worldwide. MRSA is resistant to all beta-lactam antibiotics, and alternative treatments are limited. A very limited number of new antibiotics have been discovered over the last half-century, novel agents for the treatment of MRSA infections are urgently needed. Marinopyrrole A was reported to show antibiotic activity against MRSA in 2008. After we reported the first total synthesis of (±-marinopyrrole A, we designed and synthesized a series of marinopyrrole derivatives. Our structure activity relationship (SAR studies of these novel derivatives against a panel of Gram-positive pathogens in antibacterial assays have revealed that a para-trifluoromethyl analog (33 of marinopyrrole A is ≥63-, 8-, and 4-fold more potent than vancomycin against methicillin-resistant Staphylococcus epidermidis (MRSE, methicillin-susceptible Staphylococcus aureus (MSSA and MRSA, respectively. The results provide valuable information in the search for new-generation antibiotics.
Alan J Weaver
Full Text Available This study investigated the potential antibacterial activity of three series of compounds synthesized from 12 linear and branched polyamines with 2-8 amino groups, which were substituted to produce the corresponding guanides, biguanides, or phenylguanides, against Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Antibacterial activity was measured for each compound by determining the minimum inhibitory concentration against the bacteria, and the toxicity towards mammalian cells was determined. The most effective compound, THAM trisphenylguanide, was studied in time-to-kill and cytoplasmic leakage assays against methicillin-resistant Staphylococcus aureus (MRSA, USA300 in comparison to chlorhexidine. Preliminary toxicity and MRSA challenge studies in mice were also conducted on this compound. THAM trisphenylguanide showed significant antibacterial activity (MIC ∼1 mg/L and selectivity against MRSA relative to all the other bacteria examined. In time-to-kill assays it showed increased antimicrobial activity against MRSA versus chlorhexidine. It induced leakage of cytoplasmic content at concentrations that did not reduce cell viability, suggesting the mechanism of action may involve membrane disruption. Using an intraperitoneal mouse model of invasive MRSA disease, THAM trisphenylguanide reduced bacterial burden locally and in deeper tissues. This study has identified a novel guanide compound with selective microbicidal activity against Staphylococcus aureus, including a methicillin-resistant (MRSA strain.
Full Text Available Staphylococcus aureus is the most common bacterial pathogen implicated in pyomyositis. There are increasing reports of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA infections. The present case report brings out the diverse clinical manifestations of MRSA infection in the form of paraspinal pyomyositis, myelitis, spinal osteomyelitis, and pneumonia. Molecular typing of the organism confirmed the diagnosis. Patient was successfully treated with vancomycin and surgical drainage. Consideration of the possibility of methicillin-resistance and appropriate antibiotic selection is vital in the treatment of serious community-acquired staphylococcal infections.
Full Text Available Mao Hagihara1, Takumi Umemura1, Takeshi Mori1,2, Hiroshige Mikamo11Department of Infection Control and Prevention, Aichi Medical University School of Medicine, Nagakute, Aichi, Japan; 2Division of Pharmaceutical Science, Faculty of Pharmacy, Meijo University, Nagoya, Aichi, JapanAbstract: Daptomycin is a lipoglycopeptide antibacterial drug that is rapidly bactericidal for methicillin-resistant Staphylococcus aureus (MRSA infection and has antibiotic activity against a wide range of Gram-positive organisms. It has been approved by the Ministry of Health, Labor and Welfare in Japan for the treatment for bacteremia, right-sided endocarditis, and skin and skin-structure infections, such as necrotizing fasciitis, due to MRSA on the basis of a Phase III trial conducted in Japan since July, 2011. In Japanese Phase I and III trials, daptomycin therapy given at 4 mg/kg and 6 mg/kg once per day was well tolerated and effective as standard therapy for the treatment of acute bacterial skin and skin-structure infections and bacteremia caused by MRSA, but side effects remain to be evaluated in large-scale trials.Keywords: daptomycin, methicillin-resistant Staphylococcus aureus (MRSA, Japan
William J Peppard
Full Text Available William J Peppard1, Anne Daniels1, Lynne Fehrenbacher2, Jamie Winner31Froedtert Hospital Milwaukee, Wisconsin, USA; 2Aurora St Luke’s Medical Center Milwaukee, Wisconsin, USA; 3Clement J Zablocki VA Medical Center, Milwaukee, Wisconsin, USAAbstract: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA infections have increased dramatically over the last two decades. The types of infections can range from complicated skin and skin structure infections (cSSSI to pneumonia and endocarditis. Oral antimicrobial therapy, such as trimethoprim-sulfamethoxazole, clindamycin, long-acting tetracyclines, or linezolid may provide enhanced benefit to those with uncomplicated cutaneous lesions when used in conjunction with incision and drainage in an outpatient setting. However, resistance, susceptibilities, patient-specific circumstances, and adverse effects can impact a healthcare professional’s choice of antibiotics. In patients with complicated infections requiring hospitalization or parenteral treatment, vancomycin remains the drug of choice, even though increased resistance and decreased efficacy have crept into clinical practice. Linezolid, quinupristin/dalfopristin, daptomycin, and tigecycline are alternative intravenous agents for the treatment of CA-MRSA. Investigational agents such as dalbavancin, telavancin, oritivancin, iclaprim, ceftobiprole, ceftaroline, and others may expand our therapeutic armamentarium for the treatment of infections caused by CA-MRSA in the future.Keywords: community-associated methicillin-resistant Staphylococcus aureus, CA-MRSA, complicated skin and skin structure infections, cSSSI, Panton-Valentine leukocidin, PVL, in vitro activity
Full Text Available A marked increase in the infection incidence caused by methicillin-resistant Staphylococcus aureus (MRSA strains has been noted in medical practice in recent years. This study was conducted to study the biological and characterize of MRSA-phage. Methicillin resistance of Staphylococcus aureus was detected and confirmed by determining of the MIC of oxacillin by the standard agar dilution method. Phage was biologically purified using single plaque technique, then phage characterization were studied using host range, adsorption time, particle morphology and its structural protein. MRSA phage showing lytic nature was purified by repeated plating after picking of single isolated plaques. This phage is active against all 11 isolates either of S. aureus or MRSA tested as hosts. Phage produced clear plaques indicating their lytic nature. This phage was concentrated employing polyethylene glycol (PEG-NaCl precipitation method. Morphologically, MRSA Phage has a hexagonal head having a long non-contractile tail, indicating his icosahedral nature. Adsorption studies showed 100% adsorption of MRSA-Phage after 35 minutes of exposure. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE experimentation indicated that the phage particles contain one major structural protein (about 30 Kda.
Bemis, David A; Jones, Rebekah D; Videla, Ricardo; Kania, Stephen A
Cefoxitin disk diffusion susceptibility testing is a recommended screening method for the detection of methicillin resistance in human isolates of Staphylococcus aureus and coagulase-negative staphylococci. A retrospective analysis of 1,146 clinical isolates of Staphylococcus pseudintermedius from dogs was conducted to determine if screening by the cefoxitin disk method can be similarly useful with S. pseudintermedius. The distribution of cefoxitin growth inhibition zone diameters within this collection was bimodal and correlated well with the results of methicillin resistance gene (mecA) detection by polymerase chain reaction. Of the isolates, 5% had discordant results and, when retested, 84% of these were in agreement. While a greater diversity of isolates and interlaboratory comparisons must be tested, the current study suggests that an epidemiological breakpoint (of approximately ≤ 30 mm = resistant; ≥ 31 = susceptible) can be established to predict methicillin resistance in S. pseudintermedius.
Bispo, Paulo J M; Hofling-Lima, Ana Luisa; Pignatari, Antonio C C
Staphylococcus epidermidis is an abundant member of the microbiota of the human skin and wet mucosa, which is commonly associated with sight-threatening infections in eyes with predisposing factors. Ocular S. epidermidis has become notorious because of its capability to form biofilms on different ocular devices and due to the evolving rates of antimicrobial resistance. In this study, the molecular epidemiology of 30 ocular methicillin-resistant S. epidermidis (MRSE) isolates was assessed using multilocus sequence typing (MLST). Antimicrobial resistance, accessory gene-regulator and staphylococcal cassette chromosome mec (SCCmec) types, biofilm formation, and the occurrence of biofilm-associated genes were correlated with MLST clonal complexes. Sequence types (STs) frequently found in the hospital setting were rarely found in our collection. Overall, 12 different STs were detected with a predominance of ST59 (30%), ST5 and ST6 (13.3% each). Most of the isolates (93.3%) belonged to the clonal complex 2 (CC2) and grouped mainly within subcluster CC2-II (92.9%). Isolates grouped within this subcluster were frequently biofilm producers (92.3%) with a higher occurrence of the aap (84.5%) and bhp (46.1%) genes compared to icaA (19.2%). SCCmec type IV (53.8%) was predominant within CC2-II strains, while 38.4% were nontypeable. In addition, CC2-II strains were frequently multidrug resistant (80.7%) and demonstrated to be particularly resistant to ciprofloxacin (80.8%), ofloxacin (77%), azithromycin (61.5%), and gentamicin (57.7%). Our findings demonstrate the predominance of a particular MRSE cluster causing ocular infections, which was associated with high rates of antimicrobial resistance and particularly the carriage of biofilm-related genes coding for proteinaceous factors implicated in biofilm accumulation.
Full Text Available High rate of resistance among Staphylococcus infection initiates scientists to discover new antibiotics. The objective of this study is to determine the effect of tannins isolated from the Pimenta dioica leaves on Staphylococcus aureus and methicillin resistant S. aureus as well as to evaluate their effect on hemolysin production. The antimicrobial activity of 4,6-(S-hexahydroxydiphenoyl-(α/β-D-glucopyranose and casuarinin, pedunculagin and nilocitin tannins from P. dioica was examined using agar diffusion method. Moreover, minimum inhibitory concentrations were evaluated by microtiter plate assay method. Pedunculagin and nilocitin exhibited antibacterial and anti-hemolytic effect against S. aureus. This will open the era for in vivo assessment of such compounds for clinical applications.
Full Text Available Abstract Background Surgical site infections (SSIs caused by biofilm-forming methicillin-resistant Staphylococcus pseudintermedius (MRSP have emerged as the most common hospital-acquired infections in companion animals. No methods currently exist for the therapeutic remediation of SSIs caused by MRSP in biofilms. Clarithromycin (CLA has been shown to prevent biofilm formation by Staphylococcus aureus. This study aims to assess the in vitro activity of CLA in eradicating MRSP biofilm formation on various materials. Results Quantitative assay results (P = 0.5126 suggest that CLA does not eradicate MRSP biofilm formation on polystyrene after 4 – 24 h growth periods. Scanning electron micrographs confirmed that CLA did not eradicate MRSP biofilm formed on orthopaedic implants. Conclusions By determining the in vitro characteristics and activities of MRSP isolates alone and against antibiotics, in vitro models of biofilm related infections can be made. In vitro data suggests that CLA does not effectively eradicate S. pseudintermedius biofilms in therapeutic doses.
Unnerstad Helle Ericsson
Full Text Available Abstract Background Hitherto, methicillin-resistant Staphylococcus aureus (MRSA has not been detected in Swedish cattle. However, due to the report of mecC, a novel homologue to the mecA gene, there was reason to re-evaluate susceptibility results from strain collections of Staphylococcus aureus and test suspected isolates for the presence of mecC. Findings Bovine isolates of S. aureus with elevated minimum inhibitory concentrations of beta-lactams were retrospectively tested for presence of mecC. In four of the isolates mecC was detected. Conclusion In Sweden, this is the first finding of MRSA in cattle and the first detection of MRSA harbouring mecC of domestic animal origin. MRSA in animal populations has implications as a potential reservoir with risk for spread to humans. Occurrence of MRSA among Swedish cattle appears still very limited.
Ceftobiprole is a novel broad-spectrum cephalosporin that binds with high affinity to PBP 2a, the methicillin-resistance determinant of staphylococci, and is active against methicillin- and vancomycin-resistant Staphylococcus aureus. Ceftobiprole was compared to vancomycin in a rabbit model of methicillin-resistant S. aureus aortic valve endocarditis. Ceftobiprole and vancomycin were equally effective against endocarditis caused by methicillin-resistant S. aureus strain 76, whereas ceftobipro...
Boyle, A G; Rankin, S C; Duffee, L A; Morris, D
Methicillin-resistant Staphylococcus aureus (MRSA) is recognized as a cause of nosocomial infections in both human and veterinary medicine. Studies that examine the nasopharynx and guttural pouches of the horse as carriage sites for MRSA have not been reported. MRSA colonizes the nasopharynx and guttural pouch of horses. To determine the prevalence of MRSA in equine nasopharyngeal wash (NPW) and guttural pouch lavage (GPL) samples in a field population of horses. One hundred seventy-eight samples (123 NPW and 55 GPL) from 108 horses. Prospective study. Samples were collected from a convenience population of clinically ill horses with suspected Streptococcus equi subsp. equi (S. equi) infection, horses convalescing from a known S. equi infection, and asymptomatic horses undergoing S. equi screening. Samples were submitted for S. aureus aerobic bacterial culture with mannitol salt broth and two selective agars (cefoxitin CHROMagar as the PBP2a inducer and mannitol salt agar with oxacillin). Biochemical identification of Staphylococcus species and pulsed-field gel electrophoresis (PFGE), to determine clonal relationships between isolates, were performed. Methicillin-resistant Staphylococcus (MRS) was isolated from the nasopharynx of 7/108 (4%) horses. Three horses had MRSA (2.7%), and 4 had MR-Staphylococcus pseudintermedius (MRSP). MRSA was isolated from horses on the same farm. PFGE revealed the 3 MRSA as USA 500 strains. Sampling the nasopharynx and guttural pouch of community-based horses revealed a similarly low prevalence rate of MRSA as other studies sampling the nares of community-based horses. More study is required to determine the need for sampling multiple anatomic sites when screening horses for MRSA. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.
Price, Lance B; Stegger, Marc; Hasman, Henrik; Aziz, Maliha; Larsen, Jesper; Andersen, Paal Skytt; Pearson, Talima; Waters, Andrew E; Foster, Jeffrey T; Schupp, James; Gillece, John; Driebe, Elizabeth; Liu, Cindy M; Springer, Burkhard; Zdovc, Irena; Battisti, Antonio; Franco, Alessia; Zmudzki, Jacek; Schwarz, Stefan; Butaye, Patrick; Jouy, Eric; Pomba, Constanca; Porrero, M Concepción; Ruimy, Raymond; Smith, Tara C; Robinson, D Ashley; Weese, J Scott; Arriola, Carmen Sofia; Yu, Fangyou; Laurent, Frederic; Keim, Paul; Skov, Robert; Aarestrup, Frank M
Since its discovery in the early 2000s, methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 398 (CC398) has become a rapidly emerging cause of human infections, most often associated with livestock exposure. We applied whole-genome sequence typing to characterize a diverse collection of CC398 isolates (n = 89), including MRSA and methicillin-susceptible S. aureus (MSSA) from animals and humans spanning 19 countries and four continents. We identified 4,238 single nucleotide polymorphisms (SNPs) among the 89 core genomes. Minimal homoplasy (consistency index = 0.9591) was detected among parsimony-informative SNPs, allowing for the generation of a highly accurate phylogenetic reconstruction of the CC398 clonal lineage. Phylogenetic analyses revealed that MSSA from humans formed the most ancestral clades. The most derived lineages were composed predominantly of livestock-associated MRSA possessing three different staphylococcal cassette chromosome mec element (SCCmec) types (IV, V, and VII-like) including nine subtypes. The human-associated isolates from the basal clades carried phages encoding human innate immune modulators that were largely missing among the livestock-associated isolates. Our results strongly suggest that livestock-associated MRSA CC398 originated in humans as MSSA. The lineage appears to have undergone a rapid radiation in conjunction with the jump from humans to livestock, where it subsequently acquired tetracycline and methicillin resistance. Further analyses are required to estimate the number of independent genetic events leading to the methicillin-resistant sublineages, but the diversity of SCCmec subtypes is suggestive of strong and diverse antimicrobial selection associated with food animal production. Modern food animal production is characterized by densely concentrated animals and routine antibiotic use, which may facilitate the emergence of novel antibiotic-resistant zoonotic pathogens. Our findings strongly support the idea
Full Text Available (1 Background: Several triterpenoids were found to act synergistically with classes of antibiotic, indicating that plant-derived chemicals have potential to be used as therapeutics to enhance the activity of antibiotics against multidrug-resistant pathogens. However, the mode of action of triterpenoids against bacterial pathogens remains unclear. The objective of this study is to evaluate the interaction between ursolic acid against methicillin-resistant Staphylococcus aureus (MRSA; (2 Methods: The ability of ursolic acid to damage mammalian and bacterial membranes was examined. The proteomic response of methicillin-resistant S. aureus in ursolic acid treatment was investigated using two-dimensional (2D proteomic analysis; (3 Results: Ursolic acid caused the loss of staphylococcal membrane integrity without hemolytic activity. The comparison of the protein pattern of ursolic acid–treated and normal MRSA cells revealed that ursolic acid affected a variety of proteins involved in the translation process with translational accuracy, ribonuclease and chaperon subunits, glycolysis and oxidative responses; (4 Conclusion: The mode of action of ursolic acid appears to be the influence on the integrity of the bacterial membrane initially, followed by inhibition of protein synthesis and the metabolic pathway. These findings reflect that the pleiotropic effects of ursolic acid against MRSA make it a promising antibacterial agent in pharmaceutical research.
Fogarty, Lisa R.; Haack, Sheridan K.; Johnson, Heather E.; Brennan, Angela K.; Isaacs, Natasha M.; Spencer, Chelsea
Methicillin-resistant Staphylococcus aureus (MRSA) are a threat to human health worldwide, and although detected at marine beaches, they have been largely unstudied at freshwater beaches. Genes indicating S. aureus (SA; femA) and methicillin resistance (mecA) were detected at 11 and 12 of 13 US Great Lakes beaches and in 18% or 27% of 287 recreational water samples, respectively. Eight beaches had mecA + femA (potential MRSA) detections. During an intensive study, higher bather numbers, staphylococci concentrations, and femA detections were found in samples collected after noon than before noon. Local population density, beach cloud cover, and beach wave height were significantly correlated with SA or MRSA detection frequency. The Panton-Valentine leukocidin gene, associated with community-acquired MRSA, was detected in 12 out of 27 potential MRSA samples. The femA gene was detected less frequently at beaches that met US enterococci criteria or EU enterococci ‘excellent’ recreational water quality, but was not related to Escherichia coli-defined criteria. Escherichia coli is often the only indicator used to determine water quality at US beaches, given the economic and healthcare burden that can be associated with infections caused by SA and MRSA, monitoring of recreational waters for non-fecal bacteria such as staphylococci and/or SA may be warranted.
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA is an important cause of infection, both in hospitalised patients with significant healthcare exposure and in patients without healthcare risk factors. Community-acquired methicillin-resistant S. aureus (CA-MRSA are known for their rapid community transmission and propensity to cause aggressive skin and soft tissue infections and community-acquired pneumonia. The distinction between the healthcare-associated (HA-MRSA and CA-MRSA is gradually fading owing to the acquisition of multiple virulence factors and genetic elements. The movement of CA-MRSA strains into the nosocomial setting limits the utility of using clinical risk factors alone to designate community or HA status. Identification of unique genetic characteristics and genotyping are valuable tools for MRSA epidemiological studies. Although the optimum pharmacotherapy for CA-MRSA infections has not been determined, many CA-MRSA strains remain broadly susceptible to several non-β-lactam antibacterial agents. This review aimed at illuminating the characteristic features of CA-MRSA, virulence factors, changing clinical settings and molecular epidemiology, insurgence into the hospital settings and therapy with drug resistance.
Guntupalli, Rajesh; Sorokulova, Iryna; Olsen, Eric; Globa, Ludmila; Pustovyy, Oleg; Moore, Timothy; Chin, Bryan; Barbaree, James; Vodyanoy, Vitaly
Discrimination of methicillin resistant (MRSA) and sensitive (MSSA) strains of Staphylococcus aureus, was achieved by the specially selected lytic bacteriophage with a wide host range of S. aureus strains and a penicillin-binding protein (PBP 2a) specific antibody. A quartz crystal microbalance with dissipation monitoring (QCM-D) was employed to analyze bacteria-phage interactions. The lytic phages were transformed into phage spheroids by exposure to water-chloroform interface. Phage spheroid monolayers were transferred onto QCM-D sensors by Langmuir-Blodgett (LB) technique. Biosensors were tested in the flow mode with bacterial water suspensions, while collecting frequency and energy dissipation changes. Bacteria-spheroid interactions resulted in decreased resonance frequency and an increase in dissipation energy for both MRSA and MSSA strains. Following the bacterial binding, these sensors were further exposed to a flow of the penicillin-binding protein (PBP 2a) specific antibody conjugated latex beads. Sensors tested with MRSA responded to PBP 2a antibody beads; while sensors examined with MSSA gave no response. This experimental difference establishes an unambiguous discrimination between methicillin resistant and sensitive S. aureus strains. Both free and immobilized bacteriophages strongly inhibit bacterial growth on solid/air interfaces and in water suspensions. After lytic phages are transformed into spheroids, they retain their strong lytic activity and demonstrate high bacterial capture efficiency. The phage and phage spheroids can be used for screening and disinfection of antibiotic resistant bacteria. Other applications may include use on biosensors, bacteriophage therapy, and antimicrobial surfaces.
Salaheen, Serajus; Peng, Mengfei; Joo, Jungsoo; Teramoto, Hironori; Biswas, Debabrata
The therapeutic roles of phenolic blueberry (Vaccinium corymbosum) and blackberry (Rubus fruticosus) pomace (commercial byproduct) extracts (BPE) and their mechanism of actions were evaluated against methicillin resistant Staphylococcus aureus (MRSA). Five major phenolic acids of BPE, e.g., protocatechuic, p. coumaric, vanillic, caffeic, and gallic acids, as well as crude BPE completely inhibited the growth of vegetative MRSA in vitro while BPE+methicillin significantly reduced MRSA biofilm formation on plastic surface. In addition, BPE restored the effectiveness of methicillin against MRSA by down-regulating the expression of methicillin resistance (mecA) and efflux pump (norA, norB, norC, mdeA, sdrM, and sepA) genes. Antibiogram with broth microdilution method showed that MIC of methicillin reduced from 512 μg/mL to 4 μg/mL when combined with only 200 μg Gallic Acid Equivalent (GAE)/mL of BPE. Significant reduction in MRSA adherence to and invasion into human skin keratinocyte Hek001 cells were also noticed in the presence of BPE. BPE induced anti-apoptosis and anti-autophagy pathways through overexpression of Bcl-2 gene and down-regulation of TRADD and Bax genes (inducers of apoptosis pathway) in Hek001 cells. In summary, novel and sustainable prophylactic therapy can be developed with BPE in combination with currently available antibiotics, especially methicillin, against skin and soft tissue infections with MRSA. PMID:28270804
Strohsahl, Christopher M.; Miller, Benjamin L.; Krauss, Todd D.
Staphylococcus aureus is a leading cause of human illness, and has developed the remarkable ability to resist the bactericidal capabilities of many of the world's leading antibiotics (i.e. MRSA). In an effort to enable rapid detection and treatment of MRSA infections, we have developed a DNA detection technology termed the NanoLantern(TM). The NanoLantern(TM) biosensor technology is based on the simple immobilization of a fluorophore-terminated DNA hairpin onto a gold chip. This produces a label-free sensor that allows for a positive response to be obtained without extensive processing of the sample, saving cost and increasing accuracy. We will also discuss a newly developed method of partial gene analysis, used to develop a DNA hairpin probe that is capable of detecting the presence of the mecR gene, a gene necessary for methicillin resistance to be present in S. aureus, with 100% sequence specificity. The successful incorporation of this probe into the NanoLantern(TM) platform, along with the concomitant development of the paired PCR assay has allowed for the successful detection of methicillin-resistance directly from a culture of S. aureus. These results represent an important step forward in terms of developing the ability to rapidly and effectively detect the presence of antibiotic resistance in bacterial infections.
Zouhir, Abdelmajid; Taieb, Malek; Lamine, Mohamed Ashraf; Cherif, Ammar; Jridi, Taoufik; Mahjoubi, Basma; Mbarek, Sarra; Fliss, Ismail; Nefzi, Adel; Sebei, Khaled; Ben Hamida, Jeannette
Staphylococcus aureus and methicillin-resistant S. aureus are major pathogens. The antimicrobial peptides and essential oils (EOs) display narrow- or broad-spectrum activity against bacteria including these strains. A centralized resource, such as a database, designed specifically for anti-S. aureus/anti-methicillin-resistant S. aureus antimicrobial peptides and EOs is therefore needed to facilitate the comprehensive investigation of their structure/activity associations and combinations. The database ANTISTAPHYBASE is created to facilitate access to important information on antimicrobial peptides and essential peptides against methicillin-resistant S. aureus and S. aureus. At the moment, the database contains 596 sequences of antimicrobial peptides produced by diverse organisms and 287 essential oil records. It permits a quick and easy search of peptides based on their activity as well as their general, physicochemical properties and literature data. These data are very useful to perform further bioinformatic or chemometric analysis and would certainly be useful for the development of new drugs for medical use. The ANTISTAPHYBASE database is freely available at: https://www.antistaphybase.com/ .
Moure, Raquel; Cañizares, Ángeles; Muíño, María; Lobato, Margarita; Fernández, Ana; Rodríguez, María; Gude, Maria José; Tomás, Maria; Bou, Germán
The new cobas® Cdiff and cobas® MRSA/SA tests were compared with conventional methods for the rapid detection of toxigenic Clostridium difficile and methicillin-resistant Staphylococcus aureus. The final concordance between cobas Cdiff Test and GDH/toxin gene screening was 97.62% and between cobas MRSA/SA Test and chromogenic culture, 91.30%, respectively.
W.B. van Leeuwen (Willem); C. van Pelt (Cindy); A. Luijendijk (Ad); H.A. Verbrugh (Henri); W.H.F. Goessens (Wil)
textabstractThe slide agglutination test MRSA-Screen (Denka Seiken Co., Niigata, Japan) was compared with the mecA PCR ("gold standard") for the detection of methicillin resistance in Staphylococcus aureus. The MRSA-Screen test detected the penicillin-binding protein 2a
Bondt, N.; Vijver, van de L.P.L.; Tulinski, P.; Mevius, D.; Verwer, C.
The prevalence of the methicillin-resistant Staphylococcus aureus (MRSA) among conventional pig herds in the Netherlands is high (around 71%). Nevertheless, information about the prevalence of MRSA among organic pig herds is lacking. Here, we report a study on 24 of the 49 organic pig herds in the N
VAN CLEEF, B. A G L; VAN BENTHEM, B. H B; VERKADE, E. J M; VAN RIJEN, M. M L; KLUYTMANS-VAN DEN BERGH, M. F Q; GRAVELAND, H.; BOSCH, T.; VERSTAPPEN, K. M H W; WAGENAAR, J. A.; HEEDERIK, D.; Kluijtmans, JAJW
There is limited knowledge about the effect of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) carriage on health-related quality of life (QoL). With this study, we explored whether LA-MRSA causes infections or affects health-related QoL in pig farmers. This prospective co
Cleef, van B.A.G.L.; Benthem, van B.H.B.; Verkade, E.J.M.; Rijen, van M.M.L.; Kluytmans-van den Bergh, M.F.Q.; Graveland, H.; Bosch, T.; Verstappen, K.M.H.W.; WAGENAAR, J.A.; Heederik, D.; Kluytmans, J.A.J.W.
There is limited knowledge about the effect of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) carriage on health-related quality of life (QoL). With this study, we explored whether LA-MRSA causes infections or affects health-related QoL in pig farmers. This prospective
Dodémont, Magali; Verhulst, Carlo; Nonhoff, Claire; Nagant, Carole; Denis, Olivier; Kluytmans, Jan
Three chromogenic media, chromID MRSA SMART (SMART), chromID MRSA first generation (chromID), and Brilliance MRSA (OX2), were evaluated for methicillin-resistant Staphylococcus aureus (MRSA) screening using 1,220 samples. The sensitivity at 24 h was significantly better with the SMART agar (66.4%) t
Harrison, Ewan M.; Ludden, Catherine; Brodrick, Hayley J.; Blane, Beth; Brennan, Gráinne; Morris, Dearbháile; Coll, Francesc; Reuter, Sandra; Brown, Nicholas M.; Holmes, Mark A.; O’Connell, Brian; Parkhill, Julian; Török, M.E.; Cormican, Martin; Sharon J Peacock
Abstract Background Long-term care facilities (LTCF) are potential reservoirs for methicillin-resistant Staphylococcus aureus (MRSA), control of which may reduce MRSA transmission and infection elsewhere in the healthcare system. Whole-genome sequencing (WGS) has been used successfully to understand MRSA epidemiology and transmission in hospitals and has the potential to identify transmission between these and LTCF. ...
MRS926 is a livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) strain of sequence type (ST) 398. In order to facilitate in vitro and in vivo studies of this strain, we sought to tag it with a fluorescent marker. We cloned a codon-optimized gene for TurboGFP into a shuttle vector...
Nulens, E; Stobberingh, E E; Smeets, E; van Dessel, H; Welling, M A; Sebastian, S; van Tiel, F H; Beisser, P S; Deurenberg, R H
The aim of this study was to investigate the methicillin-resistant Staphylococcus aureus (MRSA) clones isolated in a Dutch university hospital, situated near the borders of Belgium and Germany, between 2002 and 2006. MRSA strains (n = 175) were characterized using spa and SCCmec typing. The presence
Full Text Available BACKGROUND: The purpose of the present study was to describe the clinical characteristics and management of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA infections among a cohort of men who have sex with men.
Hubben, Gijs; Bootsma, Martin; Luteijn, Michiel; Glynn, Diarmuid; Bishai, David; Bonten, Marc; Postma, Maarten
Background: Screening at hospital admission for carriage of methicillin-resistant Staphylococcus aureus (MRSA) has been proposed as a strategy to reduce nosocomial infections. The objective of this study was to determine the long-term costs and health benefits of selective and universal screening fo
Bosch, T; Verkade, E; van Luit, M; Landman, F; Kluytmans, J; Schouls, L M
After the first isolation of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in 2003, this MRSA variant quickly became the predominant MRSA obtained from humans as part of the Dutch national MRSA surveillance. Previous studies have suggested that human-to-human transmissio
Full Text Available BACKGROUND: First-generation cephalosporins and antistaphylococcal penicillins are typically the first choice for treating skin and soft tissue infections (SSTI, but are not effective for infections caused by methicillin-resistant Staphylococcus aureus (MRSA. It is currently unclear what percentage of SSTIs is caused by community-associated MRSA in different regions in Canada.
Gurieva, T.; Bootsma, M.C.; Bonten, M.J.M.
Background Control of methicillin-resistant Staphylococcus aureus (MRSA) transmission has been unsuccessful in many hospitals. Recommended control measures include isolation of colonized patients, rather than decolonization of carriage among patients and/or health care workers. Yet, the potential ef
R. Coello; J. Jimenez; M. Garcia (Melissa); P. Arroyo; D. Minguez; C. Fernandez; F. Cruzet; C. Gaspar
textabstractIn the three years between November 1989 and October 1992, an outbreak of methicillin-resistantStaphylococcus aureus (MRSA) affected 990 patients at a university hospital. The distribution of patients with carriage, colonization or infection was investigated prospectively. Nosocomial acq
Nübel, Ulrich; Dordel, Janina; Kurt, Kevin
or antibiotic resistance, together with the forces driving pathogen spread. Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of hospital-acquired infections. We have investigated an MRSA strain (ST225) that is highly prevalent in hospitals in Central Europe. By using mutation discovery...
Cheryl L Main
Full Text Available BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA has been identified in prison settings in the United States. The present study investigated two clusters of skin and soft tissue infection caused by community-acquired (CA MRSA in a correctional facility in southern Ontario.
Stam-Bolink, E. M.; Mithoe, D.; Arends, J. P.; Moller, A. V. M.
Infections caused by community-acquired methicillin-resistant Staphylococcus aureus (MRSA) are emerging as a major public health problem. In this study, we describe the distribution of 54 Panton-Valentine leucocidin (PVL)-carrying MRSA isolates in the northern Netherlands between 1998 and 2005, of w
Sunkesula, Venkata; Kundrapu, Sirisha; Macinga, David R; Donskey, Curtis J
Of 82 patients with methicillin-resistant Staphylococcus aureus (MRSA) colonization, 67 (82%) had positive hand cultures for MRSA. A single application of alcohol gel (2 mL) consistently reduced the burden of MRSA on hands. However, incomplete removal of MRSA was common, particularly in those with a high baseline level of recovery.
Leroyer, Camille; Lehours, Philippe; Tristan, Anne; Boyer, Frederique; Marie, Veronique; Elleau, Christophe; Nolent, Paul; Venier, Anne-Gaelle; Brissaud, Olivier; de Barbeyrac, Bertille; Megraud, Francis; Rogues, Anne-Marie
We describe the first nosocomial outbreak of a toxic shock syndrome-positive methicillin-resistant Staphylococcus aureus (MRSA) sequence type 5 Geraldine clone. Infection control interventions that are usually successful were implemented to control the outbreak. Spread of this virulent MRSA strain highlights the need to be vigilant to MRSA antibiotic susceptibilities.
Eriksson, Jacob; Gongora, Carmen Espinosa; Stamphøj, Inga
The ecology of Staphylococcus aureus in animals has recently gained attention by the research community due to the emergence of livestock-associated methicillin-resistant strains (MRSA). We investigated carriage frequency and clonal diversity of S. aureus in 179 sheep and 17 goats in Denmark using...
Boye, Kit; Bartels, Mette Damkjær; Andersen, Ina S
A multiplex PCR with four primer-pairs was designed to identify the five main known SCCmec types. A clear and easily discriminated band pattern was obtained for all five types. The SCCmec type was identified for 98% of 312 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA...
Full Text Available ABSTRACT OBJECTIVE: In the post-sternotomy mediastinitis patients, Staphylococcus aureus is the pathogenic microorganism encountered most often. In our study, we aimed to determine the efficacy of antibiotic treatment with vancomycin and tigecycline, alone or in combination with hyperbaric oxygen treatment, on bacterial elimination in experimental S. aureus mediastinitis. METHODS: Forty-nine adult female Wistar rats were used. They were randomly divided into seven groups, as follows: non-contaminated, contaminated control, vancomycin, tigecycline, hyperbaric oxygen, hyperbaric oxygen + vancomycin and hyperbaric oxygen + tigecycline. The vancomycin rat group received 10 mg/kg/day of vancomycin twice a day through intramuscular injection. The tigecycline group rats received 7 mg/kg/day of tigecycline twice a day through intraperitoneal injection. The hyperbaric oxygen group underwent 90 min sessions of 100% oxygen at 2.5 atm pressure. Treatment continued for 7 days. Twelve hours after the end of treatment, tissue samples were obtained from the upper part of the sternum for bacterial count assessment. RESULTS: When the quantitative bacterial counts of the untreated contaminated group were compared with those of the treated groups, a significant decrease was observed. However, comparing the antibiotic groups with the same antibiotic combined with hyperbaric oxygen, there was a significant reduction in microorganisms identified (P<0.05. Comparing hyperbaric oxygen used alone with the vancomycin and tigecycline groups, it was seen that the effect was not significant (P<0.05. CONCLUSION: We believe that the combination of hyperbaric oxygen with antibiotics had a significant effect on mediastinitis resulting from methicillin-resistant Staphylococcus aureus. Methicillin-resistant Staphylococcus aureus mediastinitis can be treated without requiring a multidrug combination, thereby reducing the medication dose and concomitantly decreasing the side effects.
Bruna Gerardon Batista
Full Text Available Background and Objectives: The increased incidence of multiresistant microorganisms allied with the emergence of new mechanisms of bacterial resistance has ted treatment-related health care infections. Staphylococcus aureus has shown therapeutic limitations due to high prevalence of isolates resistant to methicillin (MRSA. The constant evolution of microorganisms in relation to antimicrobial susceptibility and rapid dissemintaion requires the introduction of new drugs in clinical practice to control infections caused by multiresistant microorganisms. In recent years, it has developed a limited number of new antimicrobial agents, among them are the 5th generation cephalosporins, ceftobiprole and ceftarolina, which have proven effective against MRSA isolates. The aim of this study was to review the literature about the characteristics and evolution of resistance in S. aureus, and about new antimicrobials used in clinical practice, featuring the main advantages and limitations of current treatment options. Methods: A literature review was performed in the MEDLINE and Scielo with papers published until the year 2014 survey was grouped according to the thematic focus following: cephalosporins, methicillin-resistant Staphylococcus aureus, combined modality therapy. Results: This study included nine scientific papers published in national and international journals for review. The articles included in this review were selected according to the information that is desired to be obtained, as follows regarding the use of antimicrobials in new anti-MRSA therapy, the main features and the advantages and limitations of current alternatives vailable. Conclusion: It is concluded that cephalosporins 5th generation is a viable therapeutic option due to the satisfactory results reported in different studies to the treatment of infections, with each hospital, determine and adapt in their clinical practice, the use of new options treatment of MRSA infections
Rehm, Susan J; Tice, Alan
The evolution of methicillin-resistant and vancomycin-resistant Staphylococcus aureus has demanded serious review of antimicrobial use and development of new agents and revised approaches to prevent and overcome drug resistance. Depending on local conditions and patient risk factors, empirical therapy of suspected S. aureus infection may require coverage of drug-resistant organisms with newer agents and novel antibiotic combinations. The question of treatment with inappropriate antibiotics raises grave concerns with regard to methicillin-resistant S. aureus selection, overgrowth, and increased virulence. Several strategies to reduce the nosocomial burden of resistance are suggested, including shortened hospital stays and outpatient parenteral antimicrobial therapy of the most serious infections.
Full Text Available Staphylococcus epidermidis is the most important member of coagulase negative staphylococci responsible for community and hospital acquired infections. Most clinical isolates of S. epidermidis are resistant to methicillin making these infections difficult to treat. In this study, correlation of methicillin resistance phenotype was compared with methicillin resistance (mecA gene carriage in 55 clinical isolates of S. epidermidis. Susceptibility was measured by disc diffusion using methicillin discs, and minimum inhibitory concentrations (MIC were measured using broth microdilution. Methicillin resistance gene (MecA gene carriage was detected by specific primers and PCR. Disc susceptibility results showed 90.9% resistance to methicillin. Considering a MIC of 4 µg/ml, 78.1% of the isolates were methicillin resistant, 76.36% of which carried the mecA gene. On the other hand, when a breakpoint of 0.5 µg/ml was used, 89.09% were methicillin resistant, of which 93.75% were mecA positive. There was a better correlation between MIC of 0.5 µg/ml with disc diffusion results and mecA gene carriage. The findings suggest that despite the usefulness of molecular methods for rapid diagnosis of virulence genes, gene carriage does not necessarily account for virulence phenotype. Ultimately, gene expression, which is controlled by the environment, would determine the outcome
Chanchaithong, Pattrarat; Prapasarakul, Nuvee
This study aimed to detect inducible clindamycin (iCLI) resistance in Staphylococcus pseudintermedius isolated from dogs in Thailand using D-zone testing. Strains that were iCLI-resistant were characterized by molecular typing and antibiogram and were detected in 10/200 S. pseudintermedius isolates (5%) from 7/41 dogs (17%). All were methicillin-resistant S. pseudintermedius (MRSP) and demonstrated multidrug resistance. The iCLI-resistant MRSP contained erm(B) and had identical or closely related DNA fingerprint patterns by pulsed-field gel electrophoresis. All iCLI-resistant MRSP strains belonged to the same clonal complex 112 (sequence types 111 and 112) by multilocus sequence typing. To avoid misinterpretation of clindamycin susceptibility, D-zone testing is recommended to promote rational antimicrobial selection and limit the clonal expansion of multidrug resistant bacteria.
Nina M. Haste
Full Text Available There is an urgent need for new antibiotics to treat hospital- and community-associated methicillin-resistant Staphylococcus aureus (MRSA infections. Previous work has indicated that both terrestrial and marine-derived members of the napyradiomycin class possess potential anti-staphylococcal activities. These compounds are unique meroterpenoids with unusual levels of halogenation. In this paper we report the evaluation of two previously described napyradiomycin derivatives, A80915A (1 and A80915B (2 produced by the marine-derived actinomycete, Streptomyces sp. strain CNQ-525, for their specific activities against contemporary and clinically relevant MRSA. Reported are studies of the in vitro kinetics of these chemical scaffolds in time-kill MRSA assays. Both napyradiomycin derivatives demonstrate potent and rapid bactericidal activity against contemporary MRSA strains. These data may help guide future development and design of analogs of the napyradiomycins that could potentially serve as useful anti-MRSA therapeutics.
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...... used for this purpose. These methods are all relatively time-consuming and not performed routinely in all laboratories. The aim of this study is to examine whether MALDI-TOF MS can be used as a fast, simple and easily implemented method for first-line discrimination of MRSA isolates. Mass spectra from...... 600 clinical MRSA isolates were included in the study, representing 89 spa types, associated with 16 different known clonal complexes. All spectra were obtained directly from colony material obtained from overnight cultures without prior protein extraction. We identified 43 useful discriminatory m/z...
Qadri, S M; Halim, M; Ueno, Y; Saldin, H
The incidence of methicillin-resistant Staphylococcus aureus (MRSA) is on the rise, especially in nosocomial and intravenous-drug-abuse-related infections, with a concomitant increase in morbidity, mortality and health care costs. At present the drug of choice, vancomycin, which must be administered intravenously, is expensive and can cause serious side effects in vancomycin-intolerant patients. Recently, minocycline has received much attention as an antibiotic to combat the increasing frequency of MRSA-related infections. We tested 102 recent clinical isolates of MRSA from tertiary-care patients and found none to be resistant to minocycline, with minimum inhibitory concentrations of < 1-2 micrograms/ml. The only other drug that inhibited all the strains was vancomycin, followed by ciprofloxacin (87%), clindamycin (55%) and chloramphenicol (52%). Gentamicin, beta-lactams, tetracycline and trimethoprim-sulfamethoxazole had little or no activity against our isolates of MRSA.
Mah, Francis S; Davidson, Richard; Holland, Edward J; Hovanesian, John; John, Thomas; Kanellopoulos, John; Shamie, Neda; Starr, Christopher; Vroman, David; Kim, Terry
Staphylococcus aureus is the most important and common pathogen that infects patients following cataract surgery, laser in situ keratomileusis, and photorefractive keratectomy. It is reported to be the second most common pathogen causing bacterial keratitis around the world. Of special concern are increasing reports of postoperative methicillin-resistant S aureus (MRSA) infection. For example, MRSA wound infections have been reported with clear corneal phacoemulsification wounds, penetrating keratoplasty, lamellar keratoplasty, and following ex vivo epithelial transplantation associated with amniotic membrane grafts. These and other data suggest that MRSA has become increasingly prevalent worldwide. In this article, we review the current medical literature and describe the current challenge of ocular MRSA infections. Recommendations are made based on an evidence-based review to identify, treat, and possibly reduce the overall problem of this organism. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.
Jensen, Jens Ulrik; Jensen, ET; Larsen, AR;
This article describes an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in two institutions for multi-handicapped children in Copenhagen. The aim of the study was to determine whether it was possible to eradicate MRSA in a setting with multi-handicapped children and staff where...... there was a high degree of physical interaction. This was a prospective interventional uncontrolled cohort study that took place from January 2003 to March 2005. All individuals in close contact with the two institutions and/or in close contact with an MRSA-colonized subject from the outbreak were included...... in the study: 38 children, 60 staff members and 12 close relatives of colonized subjects. Infection control measures included screening all individuals. When MRSA infection or colonization was found, an attempt was made to eradicate MRSA, staff education was undertaken and attempts were made to determine...
Zuo, Guo Ying; Meng, Fan Yan; Hao, Xiao Yan; Zhang, Yun Ling; Wang, Gen Chun; Xu, Gui Li
This study describes the antibacterial effect of extracts and compounds isolated from the aerial part of Chelidonium majus Linn. (Papaveraceae) acting against clinical strains of methicillin-resistant Staphylococcus aureus (MRSA). The activities were evaluated by using the macrobroth dilution method and reported as the MICs/MBCs. Bioassay-guided fractionation of the most active extract from the aerial parts (EtOAc) led to the isolation of benzo[c]phenanthridine-type alkaloids 8-hydroxydihydrosanguinarine (hhS), 8-hydroxydihydrochelerythrine (hhC), which were potently active against MRSA strains. The selective antibacterial activity reported in this paper for 8-hydroxylated benzo[c]phenanthridine-type alkaloids isolated from C.majus opens the possibility that they could be helpful for the developing of new antibacterial agents for treating the infection of MRSA which has created nosocomial problem worldwide.
Full Text Available Staphylococcus aureus is one of the most common causes of nosocomial infections. The purpose of this study was the synthesis and in vitro evaluation of antimicrobial activity of 10 new 3-oxazolidin-2-one analogues on 12 methicillin resistant S. aureus (MRSA clinical isolates. S. aureus confirmation was achieved via catalase and coagulase test. Molecular characterization of MRSA was performed by amplification of the mecA gene. Antimicrobial susceptibility was evaluated via the Kirby-Bauer disc diffusion susceptibility test protocol, using commonly applied antibiotics and the oxazolidinone analogues. Only (R-5-((S-1-dibenzylaminoethyl-1,3-oxazolidin-2-one (7a exhibited antibacterial activity at 6.6 μg. These results, allow us to infer that molecules such as 7a can be potentially used to treat infections caused by MRSA strains.
Pompilio, Arianna; Riviello, Antonella; Crocetta, Valentina; Di Giuseppe, Fabrizio; Pomponio, Stefano; Sulpizio, Marilisa; Di Ilio, Carmine; Angelucci, Stefania; Barone, Luana; Di Giulio, Andrea; Di Bonaventura, Giovanni
To evaluate the antibacterial and antibiofilm mechanisms of usnic acid (USN) against methicillin-resistant Staphylococcus aureus from cystic fibrosis patients. The effects exerted by USN at subinhibitory concentrations on S. aureus Sa3 strain was evaluated by proteomic, real-time PCR and electron microscopy analyses. Proteomic analysis showed that USN caused damage in peptidoglycan synthesis, as confirmed by microscopy. Real-time PCR analysis showed that antibiofilm activity of USN is mainly due to impaired adhesion to the host matrix binding proteins, and decreasing lipase and thermonuclease expression. Our data show that USN exerts anti-staphylococcal effects through multitarget inhibitory effects, thus confirming the rationale for considering it 'lead compound' for the treatment of cystic fibrosis infections.
Fasihi, Yasser; Fooladi, Saba; Mohammadi, Mohammad Ali; Emaneini, Mohammad; Kalantar-Neyestanaki, Davood
Molecular typing is an important tool for control and prevention of infection. A suitable molecular typing method for epidemiological investigation must be easy to perform, highly reproducible, inexpensive, rapid and easy to interpret. In this study, two molecular typing methods including the conventional PCR-sequencing method and high resolution melting (HRM) analysis were used for staphylococcal protein A (spa) typing of 30 Methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered from clinical samples. Based on PCR-sequencing method results, 16 different spa types were identified among the 30 MRSA isolates. Among the 16 different spa types, 14 spa types separated by HRM method. Two spa types including t4718 and t2894 were not separated from each other. According to our results, spa typing based on HRM analysis method is very rapid, easy to perform and cost-effective, but this method must be standardized for different regions, spa types, and real-time machinery.
van Hal, Sebastiaan J; Fowler, Vance G
For more than 4 decades, vancomycin has been the antibiotic of choice for methicillin-resistant Staphylococcus aureus (MRSA) infections. Recently, infections due to isolates with high but susceptible vancomycin minimum inhibitory concentrations have been associated with additional treatment failures and patient mortality. These poorer outcomes may in part be explained by the inability of attaining appropriate vancomycin levels in these patients. However, assumptions that these poor outcomes are solely due to failure to achieve optimal serum levels of vancomycin are premature. The availability of effective alternatives further erodes the position of vancomycin as first-line therapy. The emergence of resistance and cost considerations, however, favor a more measured approach when using alternative antimicrobials. Collectively, the current available data suggest that the optimal therapy for MRSA infections remains unclear. In the absence of further data, the Infectious Diseases Society of America guidelines remain relevant and inform clinicians of best practice for treating patients with MRSA infections.
Córdova-Guerrero, Jesús; Hernández-Guevara, Esteban; Ramírez-Zatarain, Sandy; Núñez-Bautista, Marco; Ochoa-Terán, Adrián; Muñiz-Salazar, Raquel; Montes-Ávila, Julio; López-Angulo, Gabriela; Paniagua-Michel, Armando; Nuño Torres, Gustavo A.
Staphylococcus aureus is one of the most common causes of nosocomial infections. The purpose of this study was the synthesis and in vitro evaluation of antimicrobial activity of 10 new 3-oxazolidin-2-one analogues on 12 methicillin resistant S. aureus (MRSA) clinical isolates. S. aureus confirmation was achieved via catalase and coagulase test. Molecular characterization of MRSA was performed by amplification of the mecA gene. Antimicrobial susceptibility was evaluated via the Kirby-Bauer disc diffusion susceptibility test protocol, using commonly applied antibiotics and the oxazolidinone analogues. Only (R)-5-((S)-1-dibenzylaminoethyl)-1,3-oxazolidin-2-one (7a) exhibited antibacterial activity at 6.6 μg. These results, allow us to infer that molecules such as 7a can be potentially used to treat infections caused by MRSA strains. PMID:24675696
Puneet S. Braich
Full Text Available A 47-year-old African-American woman was admitted to the intensive care unit of our community hospital for respiratory failure secondary to severe decompensated heart failure, requiring intubation. In the ensuing days, she developed a methicillin-resistant Staphylococcus aureus (MRSA infection of the cornea, despite no growth of MRSA in multiple blood, sputum, and urine cultures. This unexpected corneal infection complicated her hospital stay, and increased morbidity and disease-related cost. Risk factors, warning signs, and preventative measures for MRSA keratitis secondary to lagophthalmos (inability to completely close one's eyelids are outlined in this case report. Implementing simple precautions such as taping eyelids shut or using artificial lubrication may reduce patient morbidity and disease-related costs. These recommendations are directed to non-ophthalmic clinicians who provide care to patients in settings where MRSA colonization is widespread.
Cui, Haiying; Li, Wei; Li, Changzhu; Vittayapadung, Saritporn; Lin, Lin
The global burden of bacterial disease remains high and is set against a backdrop of increasing antimicrobial resistance. There is a pressing need for highly effective and natural antibacterial agents. In this work, the anti-biofilm effect of cinnamon oil on methicillin-resistant Staphylococcus aureus was evaluated. Then, cinnamon oil was encapsulated in liposomes to enhance its chemical stability. The anti-biofilm activities of the liposome-encapsulated cinnamon oil against MRSA biofilms on stainless steel, gauze, nylon membrane and non-woven fabrics were evaluated by colony forming unit determination. Scanning electron microscopy and laser scanning confocal microscopy analyses were employed to observe the morphological changes in MRSA biofilms treated with the encapsulated cinnamon oil. As a natural and safe spice, the cinnamon oil exhibited a satisfactory antibacterial performance on MRSA and its biofilms. The application of liposomes further improves the stability of antimicrobial agents and extends the action time.
Lovering, Andrew L; Gretes, Michael C; Safadi, Susan S; Danel, Franck; de Castro, Liza; Page, Malcolm G P; Strynadka, Natalie C J
Methicillin-resistant Staphylococcus aureus (MRSA) is an antibiotic-resistant strain of S. aureus afflicting hospitals and communities worldwide. Of greatest concern is its development of resistance to current last-line-of-defense antibiotics; new therapeutics are urgently needed to combat this pathogen. Ceftobiprole is a recently developed, latest generation cephalosporin and has been the first to show activity against MRSA by inhibiting essential peptidoglycan transpeptidases, including the β-lactam resistance determinant PBP2a, from MRSA. Here we present the structure of the complex of ceftobiprole bound to PBP2a. This structure provides the first look at the molecular details of an effective β-lactam-resistant PBP interaction, leading to new insights into the mechanism of ceftobiprole efficacy against MRSA.
Borer, Abraham; Gilad, Jacob; Yagupsky, Pablo; Peled, Nechama; Porat, Nurith; Trefler, Ronit; Shprecher-Levy, Hannah; Riesenberg, Klaris; Shipman, Miriam
Methicillin-resistant Staphylococcus aureus (MRSA) has recently been reported to emerge in the community setting. We describe the investigation and control of a community-acquired outbreak of MRSA skin infections in a closed community of institutionalized adults with developmental disabilities. In a 9-month period in 1997, 20 (71%) of 28 residents had 73 infectious episodes. Of the cultures, 60% and 32% obtained from residents and personnel, respectively, grew S. aureus; 96% and 27% were MRSA. All isolates were genetically related by pulsed-field gel electrophoresis and belonged to a phage type not previously described in the region. No known risk factors for MRSA acquisition were found. However, 58 antibiotic courses had been administered to 16 residents during the preceding 9 months. Infection control measures, antibiotic restriction, and appropriate therapy resulted in successful termination of this outbreak. Selective antibiotic pressure may result in the emergence, persistence, and dissemination of MRSA strains, causing prolonged disease. PMID:12194775
Liu, Yan; Haste, Nina M; Thienphrapa, Wdee; Li, Jerry; Nizet, Victor; Hensler, Mary; Li, Rongshi
The marine natural product, marinopyrrole A (1), was previously shown to have significant antibiotic activity against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). Although compound (1) exhibits a significant reduction in MRSA activity in the presence of human serum, we have identified key modifications that partially restore activity. We previously reported our discovery of a chloro-derivative of marinopyrrole A (1a) featuring a 2-4 fold improved minimum inhibitory concentration (MIC) against MRSA, significantly less susceptibility to serum inhibition and rapid and concentration-dependent killing of MRSA. Here, we report a novel fluoro-derivative of marinopyrrole A (1e) showing an improved profile of potency, less susceptibility to serum inhibition, as well as rapid and concentration-dependent killing of MRSA.
Sizemore, Elizabeth Nicole; Rivas, Kenya Maria; Valdes, Jose; Caballero, Joshua
A geriatric patient status post intraabdominal surgery presented with persistent diarrhoea and heavy intestinal methicillin-resistant Staphylococcus aureus (MRSA) growth after multiple courses of antibiotic therapy. Additionally, swab cultures of the anterior nares tested positive for MRSA. In order to impede infection and prevent future complications, the patient received a 10-day course of vancomycin oral solution 250 mg every 6 h, 15-day course of Saccharomyces boulardii 250 mg orally twice daily and a 5-day course of topical mupirocin 2% twice daily intranasally. Diarrhoea ceased during therapy and repeat cultures 11 days after initiating therapy demonstrated negative MRSA growth from the stool and nares. Further repeat cultures 5 months later revealed negative MRSA growth in the stools and minimal MRSA growth in the nares. Overall, enteral vancomycin and probiotics successfully eradicated MRSA infection without intestinal recurrence. Although the results were beneficial treating MRSA diarrhoea for our patient, these agents remain highly controversial.
Full Text Available Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA has become one of the most widespread causes of nosocomial infections worldwide. Recently, reports have emerged that S. aureus strains recovered from community-acquired infections are also methicillin-resistant. This study was undertaken to analyze the prevalence of methicillin resistance among isolates at a regional hospital in Trinidad, and document the current resistance profile of MRSA and methicillin-sensitive Staphylococcus aureus (MSSA to the commonly used anti-staphylococcal agents. Methods Over a 6-year period we analyzed 2430 isolates of S. aureus strains recovered from various clinical sources, from hospital and community practices. Antimicrobial susceptibility testing was done according to guideline recommendations of the National Committee for Clinical Laboratory Standards. Results The prevalence of MRSA from surgical/burn wounds, urine and pus/abscess were 60.1%, 15.5% and 6.6%, respectively. The major sources of MSSA were surgical/burn wounds, pus/abscess and upper respiratory tract specimens with rates of 32.9%, 17.1% and 14.3%, respectively. The greatest prevalence of resistance of MRSA was seen for erythromycin (86.7%, and clindamycin (75.3%. Resistance rates among MSSA were highest for ampicillin (70%. Resistance rates for tetracycline were similar among both MRSA (78.7% and MSSA (73.5%. The MRSA recovery rates from nosocomial sources (20.8% was significantly higher than that of previous years (12.5% (p Conclusion The prevalence of MRSA in the hospital increased from 12.5% in 1999 to 20.8% in 2004. Most isolates were associated with infected surgical/burn wounds which may have become infected via the hands of HCPs during dressing exercises. Infection control measures aimed at the proper hand hygiene procedures may interrupt the spread of MRSA. HCPs may also be carriers of MRSA in their anterior nares. Surveillance cultures of both patients and HCPs may help
Stevens, Claire L; Ralph, Anna; McLeod, James E T; McDonald, Malcolm I
To date, there has been scant information about the burden of methicillin-resistant Staphylococcus aureus infections in Central Australia. Our aims were to determine the proportion of Staphylococcus aureus infections due to methicillin-resistant strains in Central Australia, to characterise resistance to non-beta lactam antibiotics and to correlate findings with available demographic information. We retrospectively reviewed S. aureus isolates identified by the Microbiology Laboratory of the Pathology Department, Alice Springs Hospital between September 2005 and February 2006. Multi-resistance was defined as resistance to three or more non-beta lactam antibiotics. We identified the recovery site and extended antibiotic resistance profile of each isolate. Demographic data included place of residence, discharge diagnosis and ethnicity. There were 524 S. aureus isolates: 417 (79.6%) methicillin-sensitive S. aureus, 104 (19.7%) non-multi-resistant MRSA (nmrMRSA) and 3 (0.7%) multi-resistant MRSA (mrMRSA). MRSA accounted for 7/22 (32%) invasive infections and 91/474 (19.2%) cases of staphylococcal skin infections. Aboriginal people comprised 89 per cent (93/104) of patients with nmrMRSA; 57 per cent lived in remote communities, 21 per cent in suburban Alice Springs, and 18 per cent in Alice Springs Town Camps. Six per cent (6/104) of nmrMRSA were hospital-acquired. Of the nmrMRSA isolates, 57 per cent (59/104) were resistant to erythromycin and 7 per cent (7/104) to fusidic acid. All MRSA isolates were susceptible to co-trimoxazole. In conclusion, Central Australia has high rates of community-acquired nmrMRSA and low rates of multi-resistant MRSA. Erythromycin resistance in S. aureus is also common. These findings should prompt the review of antimicrobial prescribing guidelines for the region, especially for treatment of skin and soft tissue infections.
Maluping, R P; Paul, N C; Moodley, A
Staphylococcus pseudintermedius is a leading aetiologic agent of pyoderma and other body tissue infections in dogs and cats. In recent years, an increased prevalence of methicillin-resistant S. pseudintermedius (MRSP) has been reported. Isolation of MRSP in serious infections poses a major therapeutic challenge as strains are often resistant to all forms of systemic antibiotic used to treat S. pseudintermedius -related infections. This study investigates the occurrence of MRSP from a total of 7183 clinical samples submitted to the authors' laboratories over a 15-month period. Identification was based on standard microbiological identification methods, and by S. pseudintermedius-specific nuc polymerase chain reaction (PCR). Methicillin resistance was confirmed by PBP2a latex agglutination and mecA PCR. Susceptibility against non-beta-lactam antibiotics was carried out using a disc-diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. In addition, susceptibility to pradofloxacin--a new veterinary fluoroquinolone--was also investigated. SCCmec types were determined by multiplex PCR. Staphylococcus pseudintermedius was isolated from 391 (5%) samples and 20 were confirmed as MRSP from cases of pyoderma, otitis, wound infections, urinary tract infection and mastitis in dogs only. All 20 isolates were resistant to clindamycin and sulphamethoxazole/trimethoprim. Nineteen were resistant to chloramphenicol, enrofloxacin, gentamicin, marbofloxacin and pradofloxacin; additionally, seven isolates were resistant to tetracycline. Fifteen isolates carried SCCmec type II-III, four isolates had type V and one harboured type IV. To date, only a few scientific papers on clinical MRSP strains isolated from the UK have been published, thus the results from this study would provide additional baseline data for further investigations.
Montazeri, Effat Abbasi; Khosravi, Azar Dokht; Jolodar, Abbas; Ghaderpanah, Mozhgan; Azarpira, Samireh
Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS) as important human pathogens are causes of nosocomial infections worldwide. Burn patients are at a higher risk of local and systemic infections with these microorganisms. A screening method for MRSA by using a multiplex polymerase chain reaction (PCR) targeting the 16S ribosomal RNA (rRNA), mecA, and nuc genes was developed. The aim of the present study was to investigate the potential of this PCR assay for the detection of MRSA strains in samples from burn patients. During an 11-month period, 230 isolates (53.11%) of Staphylococcus spp. were collected from burn patients. The isolates were identified as S. aureus by using standard culture and biochemical tests. DNA was extracted from bacterial colonies and multiplex PCR was used to detect MRSA and MRCoNS strains. Of the staphylococci isolates, 149 (64.9%) were identified as S. aureus and 81 (35.21%) were described as CoNS. Among the latter, 51 (62.97%) were reported to be MRCoNS. From the total S. aureus isolates, 132 (88.6%) were detected as MRSA and 17 (11.4%) were methicillin-susceptible S. aureus (MSSA). The presence of the mecA gene in all isolates was confirmed by using multiplex PCR as a gold standard method. This study presented a high MRSA rate in the region under investigation. The 16S rRNA-mecA-nuc multiplex PCR is a good tool for the rapid characterization of MRSA strains. This paper emphasizes the need for preventive measures and choosing effective antimicrobials against MRSA and MRCoNS infections in the burn units. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.
Keni Istasaputri M.
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA is found in moderate to severe atopic dermatitis (AD and is multiresistant against topical antibiotic. Gentamycin is widely used while mupirocin is the first line therapy to eliminate MRSA. This research is intended to observe the colonization of MSRA case in AD patients and its sensitivity to mupirocin compared to gentamycin in Dermato-venereology Clinic Dr. Hasan Sadikin General Hospital Bandung. An analytical cross sectional survey was intended from 19th September–31st October 2011 in 22 moderate to severe AD patients based on objective Scoring Atopic Dermatitis and 22 healthy persons. All subjects went through skin-scraping, MSRA was detected and sensitivity test was done for mupirocin and gentamycin. The subjects consisted of 10 boys and 12 girls in both group. Based on severity, 10/22 of AD subjects were in moderate AD and 12/22 were severe AD, 14/22 of AD subjects presented with acute lesions and 8/22 subjects had chronic lesions. In the group of AD patients, 17/22 growth of S. aureus were found with sensitivity against mupirocin 14/17 and gentamycin 11/17. In healthy individual group, no S. aureus growth was found. Methicillin-resistant Staphylococcus aureus strain in AD patients was observed on 3/17 patients, and this was declared significantly different compared to healthy individuals (p <0.01. The isolates in 2/3 patients were sensitive to mupirocin and all patients were resistant to gentamycin. In conclusion, the patients of moderate to severe AD are prone to MRSA colonization and therefore requires mupirocin topical antibiotic treatment.
Full Text Available The ability to rapidly differentiate coagulase-negative staphylococcus (CoNS from Staphylococcus aureus and to determine methicillin resistance is important as it affects the decision to treat empiric antibiotic selection. The objective of this study was to evaluate CHROMagar S. aureus and CHROMagar MRSA (Becton Dickinson for rapid identification of Staphylococcus spp. directly from blood cultures. Consecutive blood culture bottles (BacT Alert 3D SA and SN, bioMérieux growing gram-positive cocci in clusters were evaluated. An aliquot was plated onto CHROMagar MRSA (C-MRSA and CHROMagar S. aureus (C-SA plates, which were read at 12 to 16 hours. C-SA correctly identified 147/147 S. aureus (100% sensitivity; 2 CoNS were misidentified as S. aureus (98% specificity. C-MRSA correctly identified 74/77 MRSA (96% sensitivity. None of the MSSA isolates grew on C-MRSA (100% specificity. In conclusion, CHROMagar is a rapid and sensitive method to distinguish MRSA, MSSA, and coagulase-negative Staphylococcus and may decrease time of reporting positive results.
Mbah, Andreas N.; Isokpehi, Raphael D
Resistance to methicillin by Staphylococcus aureus is a persistent clinical problem worldwide. A mechanism for resistance has been proposed in which methicillin resistant Staphylococcus aureus (MRSA) isolates acquired a new protein called β -lactam inducible penicillin binding protein (PBP-2′). The PBP-2′ functions by substituting other penicillin binding proteins which have been inhibited by β -lactam antibiotics. Presently, there is no structural and regulatory information on PBP-2′ protein...
Hammad, Ahmed M; Watanabe, Wataru; Fujii, Tomoko; Shimamoto, Tadashi
Staphylococci are not part of the normal fish microflora. The presence of staphylococci on fish is an indication of (a) post-harvest contamination due to poor personnel hygiene, or (b) disease in fish. The aim of this study was to determine the prevalence, molecular genetic characteristics, antibiotic resistance and virulence factors of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) isolated from 200 samples of retail ready-to-eat raw fish (sashimi) collected from the Japanese prefecture of Hiroshima. We characterized 180 staphylococcal strains. A majority of the grocery stores surveyed (92%, 23/25) contained fish contaminated with Staphylococcus species. We recovered 175 S. aureus isolates from 174 (87%, 174/200) samples, with 170 isolates of MSSA. For the MRSA and MR-CoNS, 10 isolates were obtained from 10 samples (5%, 10/200) collected from 10 shops (40%, 10/25) belonging to four supermarket chains. SCCmec typing revealed the presence of a type IV.1 SCCmec cassette in S. warneri isolates, a type II.1 SCCmec cassette in S. haemolyticus isolates and a cassette in methicillin-resistant S. aureus (MRSA) isolates that could not be typed. Molecular typing of two MRSA isolates by spa sequencing and multilocus sequence typing (MLST) identified t1767 and ST8, respectively. Antibiotic resistance genes that confer resistance to aminoglycosides, tetracyclines, β-lactams, macrolides, lincosamides and streptogramin B (MLS(B)) antibiotics were detected. Genes encoding one or more of the following virulence factors: staphylococcal enterotoxins (seb, and sed), toxic shock syndrome toxin 1 (tst), exfoliative toxin (etaA) were detected in 14.2% (25/175) of S. aureus isolates. The accessory gene regulator (agr) typing of S. aureus isolates revealed that agr type 1 was most prevalent (96.5%, 169/175) followed by type 2 (2.2%, 4/175) and type 3 (1.1%, 2/175). None of
B A Fomda
Full Text Available Background: Methicillin-resistant Staphylococcus aureus (MRSA is the most common multidrug-resistant pathogen causing nosocomial infections across the world. MRSA is not only associated with significant mortality and morbidity but also places a large economic strain on our health care system. MRSA isolates are also typically resistant to multiple, non-β-lactam antibiotics. We conducted a prospective study in a tertiary care hospital, to determine the prevalence of MRSA and to establish the clonal distribution of MRSA isolates recovered from various clinical specimens. Materials and Methods: Clinical samples were cultured and S. aureus was identified as per standard microbiological procedures. Susceptibility testing was done by agar disk diffusion and minimum inhibitory concentration (MIC method as recommended by CLSI. Methicillin resistance was detected by phenotypic methods namely, oxacillin disc diffusion (ODD, minimum inhibitory concentration (MIC of oxacillin, cefoxitin disk diffusion (CDD, and MIC of cefoxitin. Amplification of mecA gene by PCR was used as gold standard for detection of methicillin resistance. Pulsed field gel electrophoresis (PFGE typing was performed for MRSA isolates. Results: Out of 390 S. aureus isolates, 154 (39.48% isolates were MRSA and 236 (60.51% isolates were MSSA. Penicillin was the least effective antibacterial drug against the hospital associated S. aureus isolates with 85.64% resistance rate. All the isolates were susceptible to vancomycin. The MRSA showed a high level of resistance to all antimicrobials in general in comparison to the MSSA and the difference was statistically significant (P < 0.05. Multiplex PCR performed for all strains showed amplification of both the mecA and nucA genes in MRSA strains whereas MSSA strains showed amplification of only nucA gene. PFGE of these isolates showed 10 different patterns. Conclusion: Prevalence of MRSA in our hospital was 39.48%. Most of these isolates were
Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Soper, Steven A
Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital-acquired (HA-MRSA) infection worldwide. As a result, the rapid and specific detection of MRSA is crucial not only for early prevention of disease spread, but also for the effective treatment of these infections. We report here an integrated modular-based microfluidic system for MRSA identification, which can carry out the multi-step assay used for MRSA identification in a single disposable fluidic cartridge. The multi-step assay included PCR amplification of the mecA gene harboring methicillin resistance loci that can provide information on drug susceptibility, ligase detection reaction (LDR) to generate fluorescent ligation products appended with a zip-code complement that directs the ligation product to a particular address on a universal array containing zip-code probes and a universal DNA array, which consisted of a planar waveguide for evanescent excitation. The fluidic cartridge design was based on a modular format, in which certain steps of the molecular processing pipeline were poised on a module made from a thermoplastic. The cartridge was comprised of a module interconnected to a fluidic motherboard configured in a 3-dimensional network; the motherboard was made from polycarbonate, PC, and was used for PCR and LDR, while the module was made from poly(methylmethacrylate), PMMA, and contained an air-embedded waveguide serving as the support for the universal array. Fluid handling, thermal management and optical readout hardware were situated off-chip and configured into a small footprint instrument. In this work, the cartridge was used to carry out a multiplexed PCR/LDR coupled with the universal array allowed for simultaneous detection of five genes that encode for 16S ribosomal RNA (SG16S), protein A (spa), the femA protein of S. epidermidis (femA), the virulence factor of Panton-Valentine leukocidin (PVL) and the gene that confers methicillin resistance (mecA). Results
Turk, Ryen; Singh, Ameet; Rousseau, Joyce; Weese, J Scott
Methicillin resistant Staphylococcus pseudintermedius (MRSP) is an important canine pathogen that has been shown to produce biofilm in vitro. Biofilm production may be an important virulence factor and methods to eliminate biofilm-associated infections are required. An enzyme of Aggregatibacter actinomycetemcomitans, DispersinB, has been shown to degrade the extracellular matrix in the biofilm of a variety of bacteria including Staphylococcus aureus and Staphylococcus epidermidis. The objective of this study was to determine the effect of DispersinB on MRSP biofilm production and eradication in vitro. A quantitative microtitre plate assay was used to assess the impact of DispersinB on 30 MRSP isolates from dogs. While DispersinB did not have any effect on MRSP growth (P=0.98), it reduced biofilm formation (P=0.0002) and degraded established biofilm (P=0.0001). These data indicate that in vivo study of the effect of this enzyme in indicated to determine if it may be a useful treatment option for MRSP biofilm-associated infections.
Full Text Available Background: Methicillin resistant Staphylococcus aureus (MRSA nasal carriers play role in development of nosocomial infections and may increase treatment costs and mortality rate. These isolates, in addition to beta lactamase, is resistant to other drugs. Carrier frequency and spectrum awareness of drug sensitivity in these isolates will be useful in choosing more effective methods of control and treatment.Methods: Nasal anterior parts samples collected from 160 hemodialysis patients in Imam Reza hospital. After diagnosis of Staphylococcus aureus, their sensitivity to 11 different antibiotics was determined using Kirby-bauer method and oxacillin strips. MRSA isolates, MIC was determined by microdilution method.Results: Twenty-eight percent of hemodialysis patients were Staphylococcus aureus nasal carriage and 31% of the isolates were MRSA type. Penicillin was the most resistance (96% and vancomycin was the lowest resistance (0% antibiotics. Frequency of resistance to azithromycin, ciprofloxacin, cloxacillin, doxycycline, gentamicin and co-trimoxazole was 20-29% and chloramphenicol, clindamycin and rifampin was less than 10%. Most of MRSA isolates were resistance than MSSA isolates. 86% of MRSA isolates were identified as MDR. Oxacillin MIC for all MRSA isolates was more than 64 micg/ml.Conclusion: Antibiotic resistance patterns of isolated MRSA and MSSA was intirely different from each other so unlike MRSA, MSSA isolates were sensitive to the most antibiotics. Penicillin was totally ineffective and vancomycin was recognized as the most effective antibiotic in this study.
Juan Manuel Talia
Full Text Available Staphylococcus aureus, the most virulent Staphylococcus species, is also the prevalent pathogen isolated from hospitalized patients and the second most common from patients in outpatient settings. In general, bacteria have the genetic ability to transmit and acquire resistance to drugs, which are utilized as therapeutic agents. Related studies of antimicrobial activity indicate that crude extracts containing flavonoids, triterpenes and steroids have showed significative activity against several Staphylococcus aureus strains. Combination effects between flavonoids and antibiotics also have been reported. The aim of the present work was to investigate in vitro synergism between several chalcones substituted in combination with oxacillin, an antibiotic used conventionally against S. aureus ATCC 43 300 that is resistant to meticillin, using the kinetic turbidimetric method developed earlier. The results were satisfactory for all assayed combinations and in accordance with the mechanism of bacteriostatic inhibition previously proposed, except for 2´,4´-dihydroxy-3´-methoxychalcone - oxacillin. The best combination was 2´,3´-dihydroxychalcone - oxacillin (MIC: 11.2 μg/mL. Further investigations are needed to characterize the interaction mechanism with antibiotics. Thus, chalcones - oxacillin combination could lead to the development of new antibiotics against methicillin resistant S. aureus infection.
Full Text Available Aim: This study was conducted to determine the occurrence of methicillin-sensitive and Staphylococcus aureus (MSSA methicillin-resistant S. aureus (MRSA from bovine mastitis and to characterize them with respect to antibiotic resistance gene mecA. Materials and Methods: A total of 160 mastitic milk samples were screened for the presence of S. aureus. The presumptive positive isolates were confirmed using nuc and 23S rRNA gene-based polymerase chain reaction. All the confirmed isolates were subjected to in vitro antibiogram using a number of antibiotics. Isolates which showed resistance against methicillin were characterized for the presence of mecA gene. Results: Out of the total 160 milk samples, 36 (22.5% samples yielded S. aureus. The in vitro antibiogram revealed that 16.6% S. aureus isolates were resistant to all antibiotics screened for and 5.5% isolates were sensitive to all of them. Furthermore, the study found 94.4%, 83.3%, 77.7%, 66.6%, 50%, and 27.7% of S. aureus isolates resistant to penicillin, ampicillin, amoxicillin-sulbactam, enrofloxacin, ceftriaxone, and methicillin, respectively. Out of the 36 S. aureus isolates, only 6 (16.6% isolates were confirmed as MRSA while rest were MSSA. Conclusion: The higher occurrence of S. aureus-mediated mastitis was concluded due to improper hygienic and poor farm management. The multiple drug resistance reveals the indiscriminate use of drugs and presence of methicillin resistance gene determinant is an alarming situation as such infections are difficult to treat.
Guilhermetti, M; Hernandes, S E; Fukushigue, Y; Garcia, L B; Cardoso, C L
The effectiveness of hand-cleansing agents in removing a hospital strain of methicillin-resistant Staphylococcus aureus from artificially contaminated hands of five volunteers was studied. The products used were plain liquid soap, ethyl alcohol 70% (by weight), 10% povidone-iodine liquid soap (PVP-I), and chlorhexidine gluconate (4%) detergent. The experiments were performed using a Latin square statistical design, with two 5x4 randomized blocks. The removal rates of S aureus cells from contaminated fingertips were estimated by analysis of variance, the response variable being the log10 reduction factor (RF), ie, log10 of the initial counts minus log10 of the final counts. In the first and second blocks, the fingertips of the volunteers were contaminated in mean with 3.76 log10 colony-forming units ([CFU] light-contamination hand) and 6.82 log10 CFU (heavy-contamination hand), respectively. In the first block, there were significant differences between treatments (Pliquid soap (RF, 1.96) and 4% chlorhexidine (RF, 1.91). In the second block, 10% PVP-I (RF, 4.39) and 70% ethyl alcohol (RF, 3.27) also were significantly more effective than plain liquid soap (RF, 1.77) and 4% chlorhexidine (RF, 1.37; Pliquid soap was significantly more effective than chlorhexidine (4%) detergent. The results suggest that 10% PVP-I and 70% ethyl alcohol may be the most effective hand-cleansing agents for removing methicillin-resistant S aureus strain from either lightly or heavily contaminated hands.
Hell, M; Bauer, J W; Laimer, M
Methicillin-resistant Staphylococcus aureus (MRSA) isolates are a serious public health problem whose ever-increasing rate is commensurate with the pressure it is exerting on the healthcare system. At present, more than 20% of clinical S. aureus isolates in German hospitals are methicillin-resistant, in Austria less than 10%. Strategies from low-prevalence countries show that this development is not necessarily inevitable. In the Scandinavian countries and the Netherlands, thanks to a rigorous prevention programme, MRSA prevalence has been kept at an acceptably low level (< 1-3%). Central to these search-and-destroy control strategies is an admission screening using several MRSA swabs taken from mucocutaneous colonisation sites of high-risk patients (MRSA surveillance). It has also been reported that the speed with which MRSA carriage is detected has an important role, as it is a key component of any effective strategy to prevent the pathogen from spreading. Since MRSA culturing involves a 2-3 day delay before the final results are available, rapid detection techniques (commonly referred to as MRSA rapid tests) using polymerase chain reaction (PCR) methods and, most recently, rapid culturing methods have been developed. The implementation of rapid tests reduces the time of detection of MRSA carriers from 48-72 to 2-5 h. Clinical evaluation data have shown that MRSA can thus be detected with very high sensitivity. Specificity, however, is sometimes impaired due to false-positive PCR signals occurring in mixed flora specimens. In order to rule out false-positive PCR results, a culture screen must always be carried out simultaneously. The data provide preliminary evidence that a PCR assay can reduce nosocomial MRSA transmission in high-risk patients or high-risk areas, whereas an approach that screens all patients admitted to the hospital is probably not effective. Information concerning the cost effectiveness of rapid MRSA tests is still sparse and thus the issue
Pooi Yin Chung
Full Text Available Staphylococcus aureus is an important human pathogen in both hospital and the community that has demonstrated resistance to all currently available antibiotics over the last two decades. Multidrug-resistant isolates of methicillin-resistant S. aureus (MRSA exhibiting decreased susceptibilities to glycopeptides has also emerged, representing a crucial challenge for antimicrobial therapy and infection control. The availability of complete whole-genome nucleotide sequence data of various strains of S. aureus presents an opportunity to explore novel compounds and their targets to address the challenges presented by antimicrobial drug resistance in this organism. Study compounds α-amyrin [3β-hydroxy-urs-12-en-3-ol (AM], betulinic acid [3β-hydroxy-20(29-lupaene-28-oic acid (BA] and betulinaldehyde [3β-hydroxy-20(29-lupen-28-al (BE] belong to pentacyclic triterpenoids and were reported to exhibit antimicrobial activities against bacteria and fungi, including S. aureus. The MIC values of these compounds against a reference strain of methicillin-resistant S. aureus (MRSA (ATCC 43300 ranged from 64 µg/ml to 512 µg/ml. However, the response mechanisms of S. aureus to these compounds are still poorly understood. The transcription profile of reference strain of MRSA treated with sub-inhibitory concentrations of the three compounds was determined using Affymetrix GeneChips. The findings showed that these compounds regulate multiple desirable targets in cell division, two-component system, ABC transporters, fatty acid biosynthesis, peptidoglycan biosynthesis, aminoacyl-tRNA synthetase, ribosome and β-lactam resistance pathways which could be further explored in the development of therapeutic agents for the treatment of S. aureus infections.
de Moraes, Ana Carolina Mazarin; Lima, Bruna Araujo; de Faria, Andreia Fonseca; Brocchi, Marcelo; Alves, Oswaldo Luiz
Methicillin-resistant Staphylococcus aureus (MRSA) has been responsible for serious hospital infections worldwide. Nanomaterials are an alternative to conventional antibiotic compounds, because bacteria are unlikely to develop microbial resistance against nanomaterials. In the past decade, graphene oxide (GO) has emerged as a material that is often used to support and stabilize silver nanoparticles (AgNPs) for the preparation of novel antibacterial nanocomposites. In this work, we report the synthesis of the graphene-oxide silver nanocomposite (GO-Ag) and its antibacterial activity against relevant microorganisms in medicine. GO-Ag nanocomposite was synthesized through the reduction of silver ions (Ag(+)) by sodium citrate in an aqueous GO dispersion, and was extensively characterized using ultraviolet-visible absorption spectroscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. The antibacterial activity was evaluated by microdilution assays and time-kill experiments. The morphology of bacterial cells treated with GO-Ag was investigated via transmission electron microscopy. AgNPs were well distributed throughout GO sheets, with an average size of 9.4±2.8 nm. The GO-Ag nanocomposite exhibited an excellent antibacterial activity against methicillin-resistant S. aureus, Acinetobacter baumannii, Enterococcus faecalis, and Escherichia coli. All (100%) MRSA cells were inactivated after 4 hours of exposure to GO-Ag sheets. In addition, no toxicity was found for either pristine GO or bare AgNPs within the tested concentration range. Transmission electronic microscopy images offered insights into how GO-Ag nanosheets interacted with bacterial cells. Our results indicate that the GO-Ag nanocomposite is a promising antibacterial agent against common nosocomial bacteria, particularly antibiotic-resistant MRSA. Morphological injuries on MRSA cells revealed a likely loss of viability as a result of the
Full Text Available AIM: In this study, we determined the antimicrobial susceptibility of Staphylococcus aureus strains lead to nosocomial infections in a three year period including 2006, 2007 and 2008 in a 1000-bed teaching hospital. We aimed to help clinicians while choosing the appropriate antimicrobial agent in empiric theraphy and to gain epidemiological data in addition to other regional studies. METHOD: We included 408 S.aureus strains, 216 (52.9% from surgical and 192 (47.1% from medical wards. Susceptibility of isolates to methicillin and other 12 antimicrobial agents used for treatment was determined by using Kirby-Bauer disk diffusion method according to “Clinical and Laboratory Standards Institute” criteria. RESULTS: Ratio of S.aureus to all isolated strains from inpatients was 6.3% for 2006, 6.2% for 2007, 8.2% for 2008. Among all S.aureus isolates, 45.6% (186/408 were resistant to methicillin and ratio of methicillin resistant S.aureus (MRSA was 56.6% for 2006, 39.3% for 2007, 42.0% for 2008. All tested antimicrobials except trimethoprim/sulfamethoxazole exhibited higher resistance rates in methicillin resistant S.aureus strains compared to methicillin susceptible S.aureus. CONCLUSION: Enhanced surveillance and rational infection control measures should be adopted by healthcare institutions to address infections especially caused by MRSA in health-care settings. We concluded that antimicrobial susceptibility patterns of isolates from clinical materials, specific microbial profiles of hospitals and well coordinated practice between clinicians and laboratory stuff are powerful tools in guiding empirical treatment as well as pathogen spesific treatment of infectious diseases. *Bu calisma, XXXIII. Turk Mikrobiyoloji Kongresi (21-25 Ekim 2008, Bodrum’nde sunulmustur. [TAF Prev Med Bull 2010; 9(6.000: 585-590
Taherirad, Akram; Jahanbakhsh, Roghayeh; Shakeri, Fatemeh; Anvary, Shaghayegh; Ghaemi, Ezzat Allah
Background Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial and community-acquired infections around the world. Staphylococcal cassette chromosome mec (SCCmec) typing methods are often used to study MRSA molecular epidemiology. Objectives The current study was designed to explore the distribution profiles of different SCCmec types among methicillin-resistant S. aureus strains isolated from hospitals in Gorgan, in northern Iran, and to correlate the types into observed bacterial virulence factors. Materials and Methods Staphylococcal cassette chromosome mec typing of 62 MRSA strains isolated from patients and health-care workers in Gorgan was performed using multiplex polymerase chain reaction (PCR) assay. The prevalence of the strains was then compared according to isolation source, antibiotic susceptibility profiles, biofilm production, and the presence of the Panton-Valentine gene in isolates. Results The most common SCCmec type was type III, with a frequency rate of 76%, followed by types IV, I, and V, with frequency rates of 11.2%, 4.8%, and 3.2%, respectively; three isolates (4.8%) were not typeable by this method. SCCmec type I was only isolated from blood culture, and types IV and V were mainly isolated from wounds and urine samples; SCCmec type III was isolated from all of the clinically samples. All of the MRSA strains that were isolated from healthy carriers were type III. Multidrug resistance in the type III strains was higher compared to the other types. The frequencies of Panton-Valentine and biofilm production were significantly lower in the type III strains compared to the other SCCmec types (P < 0.05). Conclusions Similarly to other geographical regions of Iran, the SCCmec type III MRSA strain was the most frequently isolated strain from patients in Gorgan. Staphylococcal cassette chromosome mec type III showed fewer virulence factors compared to other SCCmec types. PMID:27800133
Toms John Peedikayil Neetu
Full Text Available Background: Globally, methicillin resistant Staphylococcus aureus (MRSA is one of the most common pathogens that causes hospital- and community-acquired infections. The use of molecular typing methods is essential for determining the origin of the isolates, their clonal relations, and also epidemiological investigations. Objective: The purpose of this study was to determine the prevalence of antibiotic-resistant MRSA investigate the accessory gene regulator (agr and staphylococcal cassette chromosome mec (SCCmec types and perform multilocus sequence typing (MLST. Furthermore, the minimum inhibitory concentration of MRSA isolates was determined for vancomycin and daptomycin. Materials and Methods: Two hundred and fifty-nine MRSA isolates were collected from Tertiary Care Hospitals in Coimbatore. Disk diffusion method was employed to assess the sensitivity of MRSA isolates to selected antibiotics and genetic analysis was performed using SCCmec, agr, and MLST typing by multiplex-polymerase chain reaction strategy. Minimal inhibitory concentration (MIC was determined using Ezy MIC (vancomycin and Biomerieux (daptomycin E-test strip. Results: Of 259 MRSA isolates, 209 (80.7% were confirmed as methicillin resistant. Antibiotic susceptibility pattern revealed that all the MRSA isolates were 100% sensitive to linezolid, rifampicin, teicoplanin, and vancomycin. MIC results showed that of 209 MRSA isolates, 10 were found to be vancomycin intermediate S. aureus and 100% of the MRSA isolates were daptomycin-susceptible. The agr group I and SCCmec Type III were the major type among MRSA isolates. In addition to these MLST typing revealed the prevalence of sequence type (ST 239 (SLV of ST8 among the MRSA isolates. Conclusion: This study confirms that ST239 (Brazilian clone of MRSA is predominant in this region which is responsible for the hospital-acquired MRSA infections. Thus, the study also suggests that vancomycin and daptomycin can still be used as an
Buzaid, Najat; Elzouki, Abdel-Naser; Taher, Ibrahim; Ghenghesh, Khalifa Sifaw
Methicillin resistant Staphylococcus aureus (MRSA) is a multidrug resistant organism that threatens the continued effectiveness of antibiotics worldwide and causes a threat almost exclusively in hospitals and long-term care settings. This study investigated the prevalence of MRSA strains and their sensitivity patterns against various antibiotics used for treating hospitalized patients in a major tertiary surgical hospital in Benghazi, Libya. We investigated 200 non-duplicate S. aureus strains isolated from different clinical specimens submitted to the Microbiology Laboratory at Aljala Surgical and Trauma Hospital, Benghazi, Libya from April to July 2007. Isolates were tested for methicillin resistance by the oxacillin disc-diffusion assay according to Clinical and Laboratory Standards Institute guidelines. MRSA strains were tested for antimicrobial resistance (i.e., vancomycin, ciprofloxacin, erythromycin, chloramphenicol and fusidic acid) using commercial discs. Information on patient demographics and clinical disease was also collected. Of the isolates examined 31% (62/200) were MRSA. No significant differences were observed in the prevalence of MRSA among S. aureus from females or males or from different age groups. Most MRSA were isolated from burns and surgical wound infections. Antibiotic resistance patterns of 62 patients with MRSA to vancomycin, ciprofloxacin, fusidic acid, chloramphenicol and erythromycin were 17.7%, 33.9%, 41.9%, 38.7% and 46.8% of cases, respectively. MRSA prevalence in our hospital was high and this may be the case for other hospitals in Libya. A sound surveillance program of nosocomial infections is urgently needed to reduce the incidence of infections due to MRSA and other antimicrobial-resistant pathogens in Libyan hospitals.
Objective To investigate the change and significance of vancomycin minimal inhibitory concentration(MIC) against methicillin-resistant Staphylococcus aureus(MRSA)isolates.Methods We analyzed the data of
de Kraker, Marlieke E. A.; Wolkewitz, Martin; Davey, Peter G.; Grundmann, Hajo
Antimicrobial resistance is threatening the successful management of nosocomial infections worldwide. Despite the therapeutic limitations imposed by methicillin-resistant Staphylococcus aureus (MRSA), its clinical impact is still debated. The objective of this study was to estimate the excess mortal
Teoh, Kar H; Jones, Sian A; Gurunaidu, Subramaniam; Pritchard, Mark G
.... Subacromial septic bursitis is a recognized but rare complication. There have been no reports of methicillin-resistant Staphylococcus aureus infections of the subacromial bursa after subacromial injections in the literature...
Full Text Available Resistance of methicillin resistant Staphylococcus aureus (MRSA were based mainly on insertion of mobile genetic elements namely Staphylococcal cassette chromosome mec (SCCmec in the chromosome of Staphylococcus aureus. SCCmec consists of recombinase genes (ccr, mec genes complex, additional resistance genes, and insertion sequences. Recombinase genes structure mediates transfer of SCCmec from one bacteria to another. Identification of SCCmec is very important to know basic genetic resistance and to predict spreading of MRSA. The aim of this research was to analyze SCCmec type and antimicrobial susceptibility patterns. The design of this study was observational analytic study by typing SCCmec and antimicrobial susceptibility testing on July– December 2007. Isolation and identification of 45 MRSA isolates was performed in the Department of Microbiology, Faculty of Medicine, University of Padjadjaran, whereas identification of mecA gene and typing of SCCmec by multiplex PCR was performed in the Department of Microbiology, Faculty of Medicine, Sriwijaya University, Palembang. The result showed that all isolates contained mecA gene. Multiplex PCR revealed that 40 MRSA isolates had SCCmec type III and 5 isolates with type IV. All SCCmec type III isolates were multiresistant and all of the type IV were not multiresistant. In conclusion, MRSA isolates with SCCmec type III was associated with multiresistant whereas type IV was not.
Schelli, Katie; Rutowski, Joshua; Roubidoux, Julia; Zhu, Jiangjiang
Recently, novel bioanalytical methods, such as NMR and mass spectrometry based metabolomics approaches, have started to show promise in providing rapid, sensitive and reproducible detection of Staphylococcus aureus antibiotic resistance. Here we performed a proof-of-concept study focused on the application of HPLC-MS/MS based targeted metabolic profiling for detecting and monitoring the bacterial metabolic profile changes in response to sub-lethal levels of methicillin exposure. One hundred seventy-seven targeted metabolites from over 20 metabolic pathways were specifically screened and one hundred and thirty metabolites from in vitro bacterial tests were confidently detected from both methicillin susceptible and methicillin resistant Staphylococcus aureus (MSSA and MRSA, respectively). The metabolic profiles can be used to distinguish the isogenic pairs of MSSA strains from MRSA strains, without or with sub-lethal levels of methicillin exposure. In addition, better separation between MSSA and MRSA strains can be achieved in the latter case using principal component analysis (PCA). Metabolite data from isogenic pairs of MSSA and MRSA strains were further compared without and with sub-lethal levels of methicillin exposure, with metabolic pathway analyses additionally performed. Both analyses suggested that the metabolic activities of MSSA strains were more susceptible to the perturbation of the sub-lethal levels of methicillin exposure compared to the MRSA strains.
Romero-Urbina, Dulce; Velazquez-Salazar, J. Jesus; Lara, Humberto H.; Arellano-Jimenez, Josefina; Larios, Eduardo; Yuan, Tony T.; Hwang, Yoon; Desilva, Mauris N.; Jose-Yacaman, Miguel
The increased number of infections due to antibiotic-resistant bacteria is a major concern to society. The objective of this work is to determine the effect of positively charged AgNPs on methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus(MRSA) cell wall using advanced electron microscopy techniques. Positively charged AgNPs suspensions were synthesized via a microwave heating technique. The suspensions were then characterized by Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) showing AgNPs size range from 5 to 30 nm. MSSA and MRSA were treated with positively charged AgNPs concentrations ranging from 0.06 mM to 31 mM. The MIC50 studies showed that viability of MSSA and MRSA could be reduced by 50% at a positively charged AgNPs concentration of 0.12 mM supported by Scanning-TEM (STEM) images demonstrating bacteria cell wall disruption leading to lysis after treatment with AgNPs. The results provide insights into one mechanism in which positively charged AgNPs are able to reduce the viability of MSSA and MRSA. This research is supported by National Institute on Minority Health and Health Disparities (G12MD007591) from NIH, NSF-PREM Grant No. DMR-0934218, The Welch Foundation and NAMRU-SA work number G1009.
Karasartova, Djursun; Cavusoglu, Zeynep Burcin; Turegun, Buse; Ozsan, Murat T; Şahin, Fikret
Bacteriophages play an important role in the pathogenicity of Staphylococcus aureus (S. aureus) either by carrying accessory virulence factors or several superantigens. Despite their importance, there are not many studies showing the actual distribution of the virulence genes carried by the prophages obtained from the clinically isolated Staphylococcus. In this study, we investigated prophages obtained from methicillin-resistant S. aureus (MRSA) strains isolated from hospital- and community-associated (HA-CA) infections for the virulence factors. In the study, 43 phages isolated from 48 MRSA were investigated for carrying toxin genes including the sak, eta, lukF-PV, sea, selp, sek, seg, seq chp, and scn virulence genes using polymerase chain reaction (PCR) and Southern blot. Restriction fragment length polymorphism was used to analyze phage genomes to investigate the relationship between the phage profiles and the toxin genes' presence. MRSA strains isolated from HA infections tended to have higher prophage presence than the MRSA strains obtained from the CA infections (97% and 67%, respectively). The study showed that all the phages with the exception of one phage contained one or more virulence genes in their genomes with different combinations. The most common toxin genes found were sea (83%) followed by sek (77%) and seq (64%). The study indicates that prophages encode a significant proportion of MRSA virulence factors.
Full Text Available Plant extracts are a valuable source of novel antibacterial compounds to combat pathogenic isolates of methicillin-resistant Staphylococcus aureus (MRSA, a global nosocomial infection. In this study, the alcoholic extract from Thai mango (Mangifera indica L. cv. ‘Fahlun’ seed kernel extract (MSKE and its phenolic principles (gallic acid, methyl gallate and pentagalloylglucopyranose demonstrated potent in vitro antibacterial activity against Staphylococcus aureus and 19 clinical MRSA isolates in studies of disc diffusion, broth microdilution and time-kill assays. Electron microscopy studies using scanning electron microscopy and transmission electron microscopy revealed impaired cell division and ultra-structural changes in bacterial cell morphology, including the thickening of cell walls, of microorganisms treated with MSKE; these damaging effects were increased with increasing concentrations of MSKE. MSKE and its phenolic principles enhanced and intensified the antibacterial activity of penicillin G against 19 clinical MRSA isolates by lowering the minimum inhibitory concentration by at least 5-fold. The major phenolic principle, pentagalloylglucopyranose, was demonstrated to be the major contributor to the antibacterial activity of MSKE. These results suggest that MSKE may potentially be useful as an alternative therapeutic agent or an adjunctive therapy along with penicillin G in the treatment of MRSA infections.
Jiamboonsri, Pimsumon; Pithayanukul, Pimolpan; Bavovada, Rapepol; Chomnawang, Mullika T
Plant extracts are a valuable source of novel antibacterial compounds to combat pathogenic isolates of methicillin-resistant Staphylococcus aureus (MRSA), a global nosocomial infection. In this study, the alcoholic extract from Thai mango (Mangifera indica L. cv. 'Fahlun') seed kernel extract (MSKE) and its phenolic principles (gallic acid, methyl gallate and pentagalloylglucopyranose) demonstrated potent in vitro antibacterial activity against Staphylococcus aureus and 19 clinical MRSA isolates in studies of disc diffusion, broth microdilution and time-kill assays. Electron microscopy studies using scanning electron microscopy and transmission electron microscopy revealed impaired cell division and ultra-structural changes in bacterial cell morphology, including the thickening of cell walls, of microorganisms treated with MSKE; these damaging effects were increased with increasing concentrations of MSKE. MSKE and its phenolic principles enhanced and intensified the antibacterial activity of penicillin G against 19 clinical MRSA isolates by lowering the minimum inhibitory concentration by at least 5-fold. The major phenolic principle, pentagalloylglucopyranose, was demonstrated to be the major contributor to the antibacterial activity of MSKE. These results suggest that MSKE may potentially be useful as an alternative therapeutic agent or an adjunctive therapy along with penicillin G in the treatment of MRSA infections.
Association of Panton Valentine Leukocidin (PVL) genes with methicillin resistant Staphylococcus aureus (MRSA) in Western Nepal: a matter of concern for community infections (a hospital based prospective study)
Bhatta, Dharm R.; Cavaco, Lina; Nath, Gopal;
Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections. Panton Valentine leukocidin (PVL) is considered one of the important virulence factors of S. aureus responsible for destruction of white blood cells, necrosis and apop......Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections. Panton Valentine leukocidin (PVL) is considered one of the important virulence factors of S. aureus responsible for destruction of white blood cells, necrosis...
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 se...... is sequence type 8 (ST8), spa type t024, and staphylococcal cassette chromosome mec element (SCCmec) type IVa....
Full Text Available Background: Methicillin-resistant Staphylococcus aureus is a bacterium that is resistance towards β-lactam antibiotics, and it seems to be one of the leading causes of nosocomial infections. Hands of the health care workers are said to be the main source for the nosocomial transmission. Thus, the study aims to determine methicillin-resistant S. aureus from the hands of Jatinangor Community Health Center’s health care workers. Methods: Samples were taken from the hands of 30 Jatinangor Community Health Center’s staffs, including medical and paramedical; from October 2012 to November 2012. Then, these samples underwent further laboratory examinations, starting from culture, identification and susceptibility test towards cefoxitin, in identifying methicillin-resistant S. aureus. Results: Out of the 30 samples taken, 6 samples (20% were positive for S. aureus isolates. In which, 4 (13.33% of the samples were positive for methicillin-resistant S. aureus. Conclusions: Since, health care workers are the main people in contact with patients and maintaining proper hand hygiene makes a huge difference; hand hygiene should be given adequate attention for the benefit of all.
Lindsay K. Drewes
@@ Background Methicillin-resistant Staphylococcus aureus (MRSA) is a type of bacteria, commonly manifesting itself in the form of skin infections, and resistant to beta-lactum antibiotics. These infections were seen in hospital settings starting in the 1960s in patients that had recently been hospitalized or undergone a medical procedure. In the 1980s reports were first published in the literature of MRSA acquired in otherwise healthy individuals from community settingsr[4,5]. An increased occurrence of community-associated Methicillin-resistant Staphylococcus aureus (CA-MRSA) has been on the rise since the late 1990s and manifests itself as a skin infection in populations without other previously known risk factors[6-8].
Full Text Available Staphylococcus aureus and coagulase-negative Staphylococcus (CoNS are frequently found in nosocomial environments as the main pathogen in several infections. In 1961, reports of nosocomial S. aureus resistant to methicillin, the drug of choice against penicillin-resistant strains, required new alternatives and vancomycin started being used to treat infections caused by methicillin-resistant S. aureus (MRSA. Community-acquired methicillin-resistant S. aureus (CA-MRSA was first reported in 1990 affecting patients without risk factors for infection with MRSA of hospital origin. MRSA of community origin harbor the genes responsible for the synthesis of Panton-Valentine leukocidin (PVL, a toxin associated with skin and soft tissue infections and that carries the staphylococcal cassette chromosome mec (SCCmec type IV. CA-MRSA emergence has caused great impact on the worldwide medical community since the presence of this pathogen in patients without risk factors represents a high risk to public health.
Weiss, Sonja; Kadlec, Kristina; Fessler, Andrea T; Schwarz, Stefan
The aim of this study was to isolate and characterize methicillin-resistant staphylococci (MRS) in a small animal clinic and to investigate their distribution and possible transmission. Swabs (n=72) were taken from hospitalized pets, the environment and employees of a small animal clinic and screened for the presence of MRS. The staphylococcal species was confirmed biochemically or by 16S rDNA sequencing. Susceptibility to antimicrobial agents was tested by broth dilution. The presence of mecA and other resistance genes was confirmed by PCR. Molecular typing of the isolates followed standard procedures. In total, 34 MRS belonging to the four species Staphylococcus aureus (n=5), Staphylococcus epidermidis (n=21), Staphylococcus haemolyticus (n=6) or Staphylococcus pettenkoferi (n=2) were isolated. All isolates were multidrug-resistant with resistance to at least three classes of antimicrobial agents. Among the five methicillin-resistant S. aureus (MRSA) isolates, four belonged to the clonal complex CC398; two of them were isolated from cats, the remaining two from pet cages. Overall, the MRS isolates differed in their characteristics, except for one S. epidermidis clone (n=9) isolated from hospitalized cats without clinical staphylococcal infections, pet cages, the clinic environment as well as from a healthy employee. This MRSE clone was resistant to 10 classes of antimicrobial agents, including aminocyclitols, β-lactams, fluoroquinolones, lincosamides, macrolides, phenicols, pleuromutilins, sulfonamides, tetracyclines and trimethoprim. These findings suggest a possible transmission of specific MRS isolates between animal patients, employees and the clinic environment.
Pohlentz, Gottfried; Xia, Guoqing; Hussain, Muzaffar; Foster, Simon; Peters, Georg
Most bacterial glycoproteins identified to date are virulence factors of pathogenic bacteria, i.e. adhesins and invasins. However, the impact of protein glycosylation on the major human pathogen Staphylococcus aureus remains incompletely understood. To study protein glycosylation in staphylococci, we analyzed lysostaphin lysates of methicillin-resistant Staphylococcus aureus (MRSA) strains by SDS-PAGE and subsequent periodic acid-Schiff’s staining. We detected four (>300, ∼250, ∼165, and ∼120 kDa) and two (>300 and ∼175 kDa) glycosylated surface proteins with strain COL and strain 1061, respectively. The ∼250, ∼165, and ∼175 kDa proteins were identified as plasmin-sensitive protein (Pls) by mass spectrometry. Previously, Pls has been demonstrated to be a virulence factor in a mouse septic arthritis model. The pls gene is encoded by the staphylococcal cassette chromosome (SCC)mec type I in MRSA that also encodes the methicillin resistance-conferring mecA and further genes. In a search for glycosyltransferases, we identified two open reading frames encoded downstream of pls on the SCCmec element, which we termed gtfC and gtfD. Expression and deletion analysis revealed that both gtfC and gtfD mediate glycosylation of Pls. Additionally, the recently reported glycosyltransferases SdgA and SdgB are involved in Pls glycosylation. Glycosylation occurs at serine residues in the Pls SD-repeat region and modifying carbohydrates are N-acetylhexosaminyl residues. Functional characterization revealed that Pls can confer increased biofilm formation, which seems to involve two distinct mechanisms. The first mechanism depends on glycosylation of the SD-repeat region by GtfC/GtfD and probably also involves eDNA, while the second seems to be independent of glycosylation as well as eDNA and may involve the centrally located G5 domains. Other previously known Pls properties are not related to the sugar modifications. In conclusion, Pls is a glycoprotein and Pls glycosyl
Silva, N C C; Guimarães, F F; Manzi, M P; Júnior, A Fernandes; Gómez-Sanz, E; Gómez, P; Langoni, H; Rall, V L M; Torres, C
The objective of this study was to analyse the prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) in milk of cows with mastitis. The California mastitis test (CMT) was used to detect the presence of mastitis in all 100 cows of a farm in Brazil. The CMT was positive in milk of 115 mammary quarters from 36 cows (36%). MRSA isolates were recovered from 4 of these 36 cows with mastitis (11%), and they were further characterized (one MRSA/sample). The four MRSA isolates were typed as t011-ST398-agr1-SCCmecV and presented two different pulsed-field-gel-electrophoresis-ApaI patterns. These four MRSA isolates showed resistance to tetracycline, streptomycin and ciprofloxacin, carried the mecA, blaZ, tet(K), and tet(M) resistance genes, and presented the S84L and S80F amino acid substitutions in GyrA and GrlA proteins, respectively. Two ST398 isolates exhibited resistance to gentamicin and tobramycin [with aac(6)-aph(2") and ant(4)-Ia genes] and one isolate resistance to clindamycin [with lnu(B) and lsa(E) genes]; this latter isolate also carried the spectinomycin/streptomycin resistance genes spw and aadE. MRSA of lineage ST398 is worldwide spread, normally multidrug resistant and may be responsible for bovine mastitis. To our knowledge, this is the first detection of MRSA-ST398 in Brazil. Few studies on the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) from bovine isolates have been performed in Brazil. MRSA of lineage ST398 is worldwide spread and associated with farm animals. Multidrug-resistant MRSA-ST398 isolates were recovered in 11% of mastitic cows from a single farm, with one isolate carrying the unusual lsa(E), spw and aadE genes. To our knowledge, this is the first detection of MRSA-ST398 isolates in milk samples of cows with mastitis in Brazil. © 2014 The Society for Applied Microbiology.
Moreno, Luisa Z; Dutra, Mauricio C; Moreno, Marina; Ferreira, Thais SP; da Silva, Givago FR; Matajira, Carlos EC; Silva, Ana Paula S; Moreno, Andrea M
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has been mainly related with pig farming, in Europe and North America, with the ST398 as the most commonly identified type of LA-MRSA. Here we present the draft genome of the first vancomycin-intermediate MRSA ST398/t9538 isolated from a swine presenting exudative epidermitis in Brazil. PMID:27759766
Paniagua-Contreras, Gloria Luz; Monroy-Pérez, Eric; Vaca-Paniagua, Felipe; RODRÍGUEZ-MOCTEZUMA,JOSÉ RAYMUNDO; Vaca, Sergio
Background Methicillin-resistant Staphylococcus aureus (MRSA) causes severe catheter-related infections in haemodialysis patients ranging from local-site infections and septic thrombophlebitis to bacteraemia but the associated virulence factors and exotoxins remain unclear. Findings We employed an in vitro infection model using reconstituted human epithelium (RHE) to analyse the expression profiles of 4 virulence genes and 12 exotoxin-coding virulence genes in 21 MRSA strains isolated from ca...
Full Text Available BACKGROUND: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA has increasingly been isolated from individuals with no predisposing risk factors; however, such strains have rarely been linked to outbreaks in the hospital setting. The present study describes the investigation of an outbreak of CA-MRSA that occurred in the maternal-newborn unit of a large community teaching hospital in Toronto, Ontario.
Paul J Planet; Diaz, Lorena; Kolokotronis, Sergios-Orestis; Narechania, Apurva; Reyes, Jinnethe; Xing, Galen; Rincon, Sandra; Smith, Hannah; Panesso, Diana; Ryan, Chanelle; Smith, Dylan P.; Guzman, Manuel De; Zurita, Jeannete; Sebra, Robert; Deikus, Gintaras
Background. The community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) epidemic in the United States is attributed to the spread of the USA300 clone. An epidemic of CA-MRSA closely related to USA300 has occurred in northern South America (USA300 Latin-American variant, USA300-LV). Using phylogenomic analysis, we aimed to understand the relationships between these 2 epidemics.
Ito, Teruyo; Katayama, Yuki; Asada, Kazumi; Mori, Namiko; Tsutsumimoto, Kanae; Tiensasitorn, Chuntima; Hiramatsu, Keiichi
The β-lactam resistance gene mecA of Staphylococcus aureus is carried by a novel mobile genetic element, designated staphylococcal cassette chromosome mec (SCCmec), identified in the chromosome of a Japanese methicillin-resistant S. aureus (MRSA) strain. We now report identification of two additional types of mecA-carrying genetic elements found in the MRSA strains isolated in other countries of the world. There were substantial differences in the size and nucleotide sequences between the ele...
Leonard, Steven N; Cheung, Chrissy M; Rybak, Michael J
We evaluated the activity of ceftobiprole against 100 community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and 100 hospital-associated MRSA (HA-MRSA) isolates. Eight isolates were evaluated by time-kill studies for kill rate and potential for synergy with tobramycin. Ceftobiprole MIC(50) and MIC(90) values were 1 and 2 microg/ml, respectively, against CA-MRSA and HA-MRSA. In time-kill analysis, ceftobiprole was bactericidal at all concentrations tested.
We evaluated the activity of ceftobiprole against 100 community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and 100 hospital-associated MRSA (HA-MRSA) isolates. Eight isolates were evaluated by time-kill studies for kill rate and potential for synergy with tobramycin. Ceftobiprole MIC50 and MIC90 values were 1 and 2 μg/ml, respectively, against CA-MRSA and HA-MRSA. In time-kill analysis, ceftobiprole was bactericidal at all concentrations tested.
Shang, Wenchi; Davies, Todd A; Flamm, Robert K; Bush, Karen
Induction of mecA by ceftobiprole and oxacillin in 18 methicillin-resistant Staphylococcus aureus clinical isolates with various SCCmec cassettes was examined using reverse transcriptase PCR. The magnitude of mecA induction, 3- to 65-fold for ceftobiprole and 2- to 69-fold for oxacillin, did not correlate with ceftobiprole MICs (or=256 microg/ml. No correlation between magnitude of induction and SCCmec type was found.
Full Text Available Abstract Background & aim: Staphylococcus aureus is one of the most important nosocomial infecting agents resistant to commonly used antibiotics. Nowadays, methicillin-resistant S. aureus (MRSA is considered one of the main causes of nosocomial infections. The aim of this study was to identify the antibiotic resistance pattern of methicicllin- resistant and susceptible strains in Ahwaz, Iran. Methods: In the present cross - sectional study, a number of 255 clinically suspected cases of Staphylococcus aureus were collected during a 19 month period. The bacteria were investigated using standard biochemical tests such as catalase, mannitol fermentation, coagulase and Dnase. Sensitive strains were confirmed by disk diffusion method compared to commonly used antibiotics. The collected data were analyzed using descriptive statistical tests. Results: of 255 suspected cases, 180 were confirmed as S.aureus, a total of 59 strains of S. aureus (2/37 percent were resistant to methicillin. Resistance to S. aureus strains resistant to methicillin included: chloramphenicol (3.38%, rifampin (45.76%, norfloxacin (89.83%, gentamicin (89.83%, ciprofloxacin, (91.52%, azithromycin, (88.13%, cotrimoxazole (86.44% and all isolates strains were sensitive to vancomycin and nitrofurantoin. A total of 10 different patterns of antibiotic resistance in methicillin-resistant Staphylococcus aureus strains were identified. Conclusion: Expression of new resistance factor in nosocomial infection is one of the major challenges in treating these infections. This study showed a high prevalence of resistance against some class of antibiotics in MRSA isolated from Imam Khomeini and Golestan hospital of Ahwaz, Iran. Key words: Nosocomial infection, Methicillin Resistant Staphylococcus aureus (MRSA, Antibiotic Resistant Pattern
Stefańska, Joanna; Antoszczak, Michał; Stępień, Karolina; Bartoszcze, Michał; Mirski, Tomasz; Huczyński, Adam
For the first time, a series of tertiary amides of polyether antibiotic-Salinomycin have been obtained and screened for their antibacterial activity against different strains of bacteria, including Bacillus anthracis and clinical methicillin-resistant Staphylococcus epidermidis (MRSE). Moreover, biofilm inhibition of MRSE and genotoxicity tests against Bacillus subtilis have been performed. Our studies show that Salinomycin and its some derivatives are active against tested bacteria and exhibited definitely bacteriostatic, not bactericidal activity.
Full Text Available Daptomycin has been used with success for the treatment of right-sided methicillin-resistant Staphylococcus aureus (MRSA endocarditis. However, its efficacy has not been completely assessed for the treatment of MRSA endocarditis when it is associated with pulmonary septic emboli. Hereby, we present a case of MRSA mitral and tricuspid native valve endocarditis with pulmonary septic emboli, which was treated with daptomycin as a sole agent, resulting in worsening pulmonary infiltrates and treatment failure.
Background & objectives: Multidrug-resistance of methicillin-resistant Staphylococcus aureus (MRSA) is a serious therapeutical problem. Chalcones belong to a group of naturally occurring flavonoids, usually found in various plant species, and have potent antibacterial, antiviral and antifungal activities. The goal of this study was to evaluate the antibacterial effect of three newly-synthesized chalcones against clinical isolates of MRSA, and their synergism with β-lactam and non- β-lactam an...
von Salm, Jacqueline L; Witowski, Christopher G; Fleeman, Renee M; McClintock, James B; Amsler, Charles D; Shaw, Lindsey N; Baker, Bill J
A new rearranged spongian diterpene, darwinolide, has been isolated from the Antarctic Dendroceratid sponge Dendrilla membranosa. Characterized on the basis of spectroscopic and crystallographic analysis, the central seven-membered ring is hypothesized to originate from a ring-expansion of a spongian precursor. Darwinolide displays 4-fold selectivity against the biofilm phase of methicillin-resistant Staphylococcus aureus compared to the planktonic phase and may provide a scaffold for the development of therapeutics for this difficult to treat infection.
Halebeedu Prakash, Pradeep; Rajan, Vineeth; Gopal, Shubha
Device associated infections caused by Staphylococcus aureus in hospitalised patients is a serious healthcare problem. The present study was designed to determine the prevalence of biofilm-producing MRSA in device-associated infections. Device-associated S. aureus strains (n=200) obtained from two tertiary care hospitals in Mysuru city, India were screened for biofilm production, antibiotic resistance, Panton-Valentine Leucocidin genes, SCCmec-types, spa-types, and intercellular adhesion (icaAD) dependent and independent genes. The efficacy of antibiotics (linezolid, vancomycin and rifampicin) on biofilms was studied using MTT assay, and the results were correlated with the occurrence of ica-dependent and independent factors. Multidrug resistance was observed in 155 strains (77.5%), and 124 strains (62%) were identified as biofilm producers. Methicillin resistance was identified in 145 strains (72.5%), and SCCmec typing of these isolates revealed high prevalence of type IV and type V. They also showed increased prevalence of pvl gene. icaAD was identified in 65 isolates, with 37 isolates showing both icaAD and ica-independent genes. spa types t852 and t657 were predominantly observed in MRSA isolates. Those isolates that had both ica-dependent and ica-independent genes showed more resistance to the screened antibiotics than the ica-dependent alone. This study reports a high prevalence of SCCmec type IV and V in biofilm producing S. aureus strains isolated from device-associated infections. Increased prevalence of pvl in SCCmec types IV and V strains suggests the role of community associated S. aureus in device-associated infections. The simultaneous presence of ica-dependent and independent genes increased the antibiotic resistance in established biofilms. Thus, S. aureus on medical devices is a potential risk for patients. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.
Cooper, Celia; Ochota, Meredith A
In September 2001, the South Australian state-wide methicillin-resistant Staphylococcus aureus (MRSA) surveillance system was expanded to include three surveillance indicators namely: estimated MRSA burden, MRSA morbidity and estimated MRSA acquisition. The last two indicator rates have been stratified into intensive care unit (ICU) versus non-ICU. Between September 2001 and March 2002, state-wide MRSA burden rates (prevalence) ranged from 27.5 to 39.8 per 10,000 occupied bed days (OBDs). Acquisition rates ranged from 28.2 to 69.0 per 10,000 OBDs (ICU) and 6.3 to 10.1 per 10,000 OBDs (non-ICU). Morbidity rates ranged from 12.9 to 43.1 per 10,000 OBDs (ICU) and 3.0 to 5.0 per 10,000 OBDs (non-ICU). In association with the changes to surveillance indicators, a new monthly surveillance report was developed. Assuring confidentiality to individual contributing hospitals has been a major consideration in the development of the data collection system. Individual contributors have access only to their own indicator rates and pooled state-wide indicator rates. Contributing institutions are urged to use great caution if wishing to compare their own rates with state-wide rates. In particular, contributors are asked to take inter-institutional differences in MRSA burden and casemix complexity into account when making such comparisons.
Lawrence A. Lavery
Full Text Available Objective: The purpose of this study was to evaluate risk factors for methicillin-resistant Staphylococcus aureus (MRSA in patients hospitalized for diabetic foot infections. Methods: We reviewed hospital admissions for foot infections in patients with diabetes which had nasal swabs, and anaerobic and aerobic tissue cultures at the time of admission. Data collected included patient characteristics and medical history to determine risk factors for developing an MRSA infection in the foot. Results: The prevalence of MRSA in these infections was 29.8%. Risk factors for MRSA diabetic foot infections were history of MRSA foot infection, MRSA nasal colonization, and multidrug-resistant organisms (p<0.05. Positive predictive value (PPV and negative predictive value (NPV of nasal colonization with MRSA to identify MRSA diabetic foot infections were 66.7% and 80.0% (sensitivity 41%, specificity 90%. Admission from a nursing home was not a significant risk factor. Conclusion: Positive nasal swabs are not predictive of the infecting agent; however, a negative nasal swab rules out MRSA as the infecting agent in foot wounds with 90% accuracy.
Full Text Available Methicillin-resistant Staphylococcus pseudintermedius (MRSP is of worldwide concern in veterinary medicine. The identification of resistant strains is necessary for proper treatment and the prevention of its propagation among animals. This study aimed to identify S. pseudintermedius isolated from canine pyoderma and evaluate their resistance profiles. Lesions from 25 dogs with pyoderma were sampled. Bacterial isolates were subjected to phenotypic and genotypic analysis for identification of the causative agent. S. pseudintermedius isolates were subjected to SmaI macrorestriction analysis and PFGE for genetic grouping, and PCR to identify the presence of the mecA gene. Their resistance profiles against 12 antimicrobials were also assessed. According to the microbiological analysis, 70 of the 75 isolates obtained were S. pseudintermedius. The isolates presented PFGE patterns, with similarity varying between 84.6 and 100%, and were grouped into 19 clusters. Despite a high frequency of mecA-positive isolates (66 out 70, only 12 presented resistances to oxacillin. Multi-resistance was identified in 29 isolates. The high frequency of MRSP isolated in this study highlights the relevance of identifying resistant strains to lead proper clinical treatment.
Gücükoğlu, Ali; Çadirci, Özgür; Terzi, Göknur; Kevenk, T Onur; Alişarli, Mustafa
The aim of this study was to determine the prevalence of enterotoxigenic and methicillin-resistant Staphylococcus aureus in ice creams. After culture-based identification of isolates, the presence of 16S rRNA and nuc was confirmed by mPCR. S. aureus was identified in 18 of 56 fruity (32.1%), 4 of 32 vanilla (12.5%), and 1 of 12 chocolate (8.3%) ice creams. S. aureus was identified as 38 isolates in 23 ice cream samples by culture-based techniques, but only 35 isolates were confirmed by PCR as S. aureus. To determine the enterotoxigenic properties of PCR-confirmed S. aureus isolates, a toxin detection kit was used (SET RPLA®). Of the 12 enterotoxigenic S. aureus isolates, 9 SEB (75%), 1 SED (8.3%), 1 SEB+SED (8.3%), and 1 SEA+SEB+SED (8.3%) expressing isolates were found. The presence of enterotoxin genes (sea, seb, sed) was identified in 13 (37.1%) out of 35 isolates by the mPCR technique. In the ice cream isolates, the sea, seb, and sed genes were detected: 1 sea (7.6%), 9 seb (69.2%), 1 sed (7.6%), 1 seb+sed (7.6%), and 1 sea+seb+sed (7.6%), respectively. The sec gene was not detected in any of these isolates. One of the 35 (2.8%) S. aureus strain was mecA positive.
Chu, Ming; Zhang, Ming-Bo; Liu, Yan-Chen; Kang, Jia-Rui; Chu, Zheng-Yun; Yin, Kai-Lin; Ding, Ling-Yu; Ding, Ran; Xiao, Rong-Xin; Yin, Yi-Nan; Liu, Xiao-Yan; Wang, Yue-Dan
Berberine is an isoquinoline alkaloid widely used in the treatment of microbial infections. Recent studies have shown that berberine can enhance the inhibitory efficacy of antibiotics against clinical multi-drug resistant isolates of methicillin-resistant Staphylococcus aureus (MRSA). However, the underlying mechanisms are poorly understood. Here, we demonstrated that sub-minimum inhibitory concentrations (MICs) of berberine exhibited no bactericidal activity against MRSA, but affected MRSA biofilm development in a dose dependent manner within the concentration ranging from 1 to 64 μg/mL. Further study indicated that berberine inhibited MRSA amyloid fibrils formation, which consist of phenol-soluble modulins (PSMs). Molecular dynamics simulation revealed that berberine could bind with the phenyl ring of Phe19 in PSMα2 through hydrophobic interaction. Collectively, berberine can inhibit MRSA biofilm formation via affecting PSMs’ aggregation into amyloid fibrils, and thereby enhance bactericidal activity of antibiotics. These findings will provide new insights into the multiple pharmacological properties of berberine in the treatment of microbial-generated amyloid involved diseases.
Full Text Available In the present study, the leaves of Rhus javanica (R. javanica were extracted with ethanol, and we investigated the antimicrobial activity of the ethanol extract of R. javanica against methicillin-resistant Staphylococcus aureus (MRSA. Control groups were treated with media containing 0.1% DMSO. The ethanol extract of R. javanica inhibited the growth of MRSA at concentrations ranging from 0.05 to 0.2 mg/mL and inhibited acid production at concentrations higher than 0.1 mg/mL (P<0.05. MRSA biofilm formation was determined by scanning electron microscopy and safranin staining. The ethanol extract of R. javanica inhibited the formation of MRSA biofilms at concentrations higher than 0.05 mg/mL. In confocal laser scanning microscopy, high concentration (0.4–1.6 mg/mL of R. javanica extract showed bactericidal effect in a dose-dependent manner. In real-time PCR analysis, R. javanica extract showed the inhibition of the genetic expression of virulence factors such as mecA, sea, agrA, and sarA in MRSA. Preliminary phytochemical analysis revealed the strong presence of phenolics. These results suggest that R. javanica may be a useful medicinal plant for inhibiting MRSA, which may be related to the presence of phenolics in the R. javanica extract.
Ozkurt, Zulal; Erkut, Bilgehan; Kadanali, Ayten; Ates, Azman; Yekeler, Ibrahim
A 36-year-old, 7-week-gravida patient with catheter-related nosocomial infective endocarditis due to methicillin-resistant Staphylococcus aureus (MRSA) is presented in this paper. The patient was admitted to our hospital because of carbon monoxide intoxication. After 14 days, MRSA catheter-related bacteremia developed. The central venous catheter was immediately removed, and teicoplanin therapy was started. Because of persistent fever, leukocytosis, and high C-reactive protein values, endocarditis was suspected. A transesophageal echocardiogram revealed 19-mm vegetation on her mitral valve, confirming the diagnosis of endocarditis. Gentamicin and rifampicin were added to the therapy regimen, and the dose of teicoplanin was increased to 12 mg/kg-day. After 8 days, a splenic abscess was detected by ultrasonography. Vegetation excision, mitral valve replacement by open-heart surgery and splenectomy were performed in the same operation. Antibiotherapy was continued for 6 weeks after surgery, and the patient's condition improved. The development of endocarditis could be prevented by proper clinical practices.
VanEperen, Alison S; Segreti, John
Methicillin-resistant Staphylococcus aureus (MRSA) continues to be an important pathogen worldwide, with high prevalence of infection in both community and hospital settings. Timely and appropriate choice of empirical therapy in the setting of MRSA infection is imperative due to the high rate of associated morbidity and mortality with MRSA infections. Initial choices should be made based on the site and severity of the infection, most notably moderate skin and soft tissue infections which may be treated with oral antibiotics (trimethoprim-sulfamethoxazole, clindamycin, doxycycline/minocycline, linezolid) in the outpatient setting, versus choice of parenteral therapy in the inpatient setting of more invasive or severe disease. Though the current recommendations continue to strongly rely on vancomycin as a standard empiric choice in the setting of severe/invasive infections, alternative therapies exist with studies supporting their non-inferiority. This includes the use of linezolid in pneumonia and severe skin and skin structure infections (SSSI) and daptomycin for MRSA bacteremia, endocarditis, SSSIs and bone/joint infections. Additionally, concerns continue to arise in regards to vancomycin, such as increasing isolate MICs, and relatively high rates of clinical failures with vancomycin. Thus, the growing interest in vanomycin alternatives, such as ceftaroline, ceftobribole, dalbavancin, oritavancin, and tedizolid, and their potential role in treating MRSA infections.
Ouchenane, Z; Smati, F; Rolain, J-M; Raoult, D
The epidemiology of Staphylococcus aureus has changed radically since 1999, in particular, methicillin-resistant S. aureus (MRSA), originally restricted to hospital, has emerged as a significant pathogen in the community, and true community-acquired MRSA (CA-MRSA) infections have been reported in patients with no clear risk factors. CA-MRSA strains frequently produce Panton-Valentine leukocidin (PVL). The objectives of this study were: (i) to monitor the prevalence of PVL and toxic shock syndrome toxin-1 (TSST-1) isolates MRSA; (ii) to identify the staphylococcal cassette chromosome (SCCmec) types of MRSA isolates. Sixty-four isolates, collected between 2005 and 2007 in Didouche Mourad hospital of Algeria. The isolates were identified by conventional methods. The antibiotic susceptibility of the isolates was performed using the disk diffusion method and automat Vitek2. The presence of gene mecA, the genes encoding SCCmec type, PVL and TSST-1 toxins were investigated by real-time PCR. All strains were gene mecA positives, 32 (50%) harboured SCCmec IV type, 28 (43.75%) harboured SCCmec V type. 19 (29.68%) have been identified positive for the leukocidin toxin (PVL), they harboured SCCmec type IV. The virulence factor TSST-1 was not present among these isolates. These results show a high prevalence of PVL-positive H-MRSA in our wards. Copyright © 2010. Published by Elsevier SAS.
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA has been emerging worldwide as one of the most important problems in communities and hospitals. Therefore, new agents are needed to treat acute oral infections from MRSA. In this study, antibacterial compounds from the roots of Atractylodes japonica (A. japonica were isolated and characterized. The compounds were isolated from the root extracts using HPLC-piloted activity-guided fractionations. Four A. japonica compounds were isolated and identified as atractylenolide III (1, atractylenolide I (2, diacetylatractylodiol [(6E,12E-tetradeca-6,12-diene-8,10-diyne-1,3-diol diacetate, TDEYA, 3. and (6E,12E-tetradecadiene-8,10-diyne-1,3-diol (TDEA, 4, which was obtained by hydrolysis of TDEYA. The minimum inhibitory concentrations (MICs was determined in the setting of clinical MRSA isolates. Compound 4 showed anti-MRSA activity with a MIC value of 4-32 μg/mL. The overall results provide promising baseline information for the potential use of the extract of A. japonica as well as some of the isolated compounds in the treatment of bacterial infections.
Full Text Available Objective:Methicillin-resistant Staphylococcus aureus (MRSA widely distributed in hospitals around the world. There is strong relationship between disease development and S. aureus nasal carriage. The aim of this study was to evaluate the prevalence and epidemiology of nasal colonization with S. aureus and MRSA in the community of Duhok city, Iraq. Methods: 489 students aged 16 to18 years were included. Nasal swab samples were collected followed by antimicrobial susceptibility test. MRSA isolates were selected and investigated for the mecA gene. Also the prevalence of PantonValentine Leukocidin (PVL gene was also studied. Results: A total of 90 (18.4% out of 489 (18.4% of the students were found to be colonized by S. aureus . Only 10 (2.04% of the students were found to be MRSA carrier. All MRSA isolates were sensitive to Vancomycin. PLV gene was detected in one MRSA strain. Conclusion: This is the first study investigating S. aureus colonization in students in the Duhok city. Nasal carriage of S. aureus and MRSA is comparable with reports from elsewhere. Fortunately, all trains included in our study were sensitive to vancomycin. Further research is needed to examine the SCCmec elements and the evolution of MRSA over the time. J Microbiol Infect Dis 2014;4(2: 59-63
Porrero, M Concepción; Mentaberre, Gregorio; Sánchez, Sergio; Fernández-Llario, Pedro; Gómez-Barrero, Susana; Navarro-Gonzalez, Nora; Serrano, Emmanuel; Casas-Díaz, Encarna; Marco, Ignasi; Fernández-Garayzabal, José-Francisco; Mateos, Ana; Vidal, Dolors; Lavín, Santiago; Domínguez, Lucas
Methicillin-resistant Staphylococcus aureus (MRSA) is a life-threatening pathogen in humans and its presence in animals is a public health concern. The aim of this study was to measure the prevalence of MRSA in free-living wild animals. Samples from red deer (n=273), Iberian ibex (n=212), Eurasian Griffon vulture (n=40) and wild boar (n=817) taken from different areas in Spain between June 2008 and November 2011 were analyzed. Characterization of the isolates was performed by spa typing, multi-locus sequence typing (MLST) and antimicrobial susceptibility testing. A low prevalence of MRSA was found with 13 isolates obtained from 12 animals (0.89%; 95% CI: 0.46-1.56). All MRSA sequence types belonged to ST398 (t011 and t1451) and ST1 (t127). Genotypes and antimicrobial susceptibility patterns (tetracycline resistance in ST398 and clindamycin-erythromycin-tetracycline resistance in ST1) suggest that the MRSA found probably originated in livestock (ST398) or humans (ST1). This is the first report of MRSA carriers in free-living wild animals in Europe. Although our data showed that MRSA prevalence is currently low, free-living wild animals might act as reservoir and represent a potential risk for human health.
Rutala, W A; Katz, E B; Sherertz, R J; Sarubbi, F A
During an outbreak of infections caused by methicillin-resistant (MR) Staphylococcus aureus in our burn unit, we conducted an extensive 10-week study to define the environmental epidemiology of the organism. The inanimate environment in patient rooms and adjacent areas was examined by using volumetric air samplers and Rodac plates. Airborne and surface level contamination with MR S. aureus was quantitated, and overall, MR S. aureus comprised 16, 31, and 40% of all bacterial growth from air, elevated surfaces, and floor surfaces, respectively. Mean air, elevated surface, and floor surface MR S. aureus contamination in rooms of MR S. aureus-infected burn patients were 1.9 MR S. aureus per ft3 (ca. 0.028 m3), 20 MR S. aureus per Rodac plate and 48 MR S. aureus per Rodac plate, respectively. Peak patient room environmental contamination levels were 6.9 MR S. aureus per ft3 of air, 70 MR S. aureus per Rodac plate per elevated surface and 138 MR S. aureus per Rodac plate per floor surface. Environmental contamination levels in the adjacent work areas were considerably lower than in infected patient rooms. There was ample opportunity for contamination of personnel through the inanimate environment in this unit. PMID:6630447
Rebic, Velma; Budimir, Ana; Aljicevic, Mufida; Bektas, Sabaheta; Vranic, Sabina Mahmutovic; Rebic, Damir
Background: Methicillin resistant Staphylococcus aureus (MRSA) is responsible for a wide spectrum of nosocomial and community associated infections worldwide. The aim of this study was to analyze MRSA strains from the general population in Canton Sarajevo, B&H. Methods: Our investigation including either phenotypic and genotypic markers such as antimicrobial resistance, pulsed-field gel electrophoresis (PFGE), SCC typing, and Panton-Valentine leukocidin (PVL) detection. Results: Antimicrobial susceptibility: all MRSA isolates were resistant to the β-lactam antibiotics tested, and all isolates were susceptible trimethoprim sulphamethoxazole, rifampicin, fusidic acid, linezolid and vancomycin. Sixty-eight per cent of the MRSA isolates were resistant to erythromycin, 5% to clindamycin, 5% to gentamicin and 4% to ciprofloxacin. After the PFGE analysis, the isolates were grouped into five similarity groups: A-E. The largest number of isolates belonged to one of two groups: C: 60 (60%) and D: 27 (27%). In both groups C and D, SCCmec type IV was predominant (60% and 88, 8%, respectively). A total of 24% of the isolates had positive expression of PVL genes, while 76% showed a statistically significantly greater negative expression of PVL genes. Conclusion: SCCmec type IV, together with the susceptibility profile and PFGE grouping, is considered to be typical of CA-MRSA PMID:27708486
Guntupalli, Rajesh; Sorokulova, Iryna; Krumnow, April; Pustovyy, Oleg; Olsen, Eric; Vodyanoy, Vitaly
Staphylococcus aureus (S. aureus)-specific bacteriophage was used as a probe for detection of methicillin-resistant S. aureus (MRSA) in aqueous solution using a novel optical method. Biorecognition phage monolayers transferred to glass substrates using Langmuir-Blodgett (LB) technique were exposed individually to MRSA in solution at logarithmic concentrations ranging from 10(6) to 10(9)cfu/ml, and observed for real-time binding using a CytoViva optical light microscope system. Results indicate that LB monolayers possessed high levels of elasticity (K), measuring 22 and 29 mN/m for 10(9) and 10(11)pfu/ml phage concentrations, respectively. Near-instantaneous MRSA-phage binding produced 33+/-5%, 10+/-1%, 1.1+/-0.1%, and 0.09+/-0.01% coverage of the substrate that directly correlated to a decrease in MRSA concentrations of 10(9), 10(8), 10(7), and 10(6)cfu/ml. The exclusive selectivity of phage monolayers was verified with Salmonella enterica subsp. enterica serovar typhimurium (S. typhimurium) and Bacillus subtilis.
Tohidpour, A; Sattari, M; Omidbaigi, R; Yadegar, A; Nazemi, J
Antimicrobial properties of plants essential oils (EOs) have been investigated through several observations and clinical studies which purpose them as potential tools to overcome the microbial drug resistance problem. The aim of this research is to study the antibacterial effect of two traditional plants essential oils, Thymus vulgaris and Eucalyptus globulus against clinical isolates of Methicillin resistant Staphylococcus aureus (MRSA) and other standard bacterial strains through disk diffusion and agar dilution methods. Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GC/MS) analysis examined the chemical composition of the oils. Results revealed both of oils to possess degrees of antibacterial activity against Gram (+) and Gram (-) bacteria. T. vulgaris EO showed better inhibitory effects than E. globulus essential oil. GC analysis of T. vulgaris resulted in thymol as the oil major compound whereas GC/MS assay exhibited eucalyptol as the most abundant constitute of E. globulus EO. These results support previous studies on these oils and suggest an additional option to treat MRSA infections. Clinical and further analytical trials of these data are necessary to confirm the obtained outcomes. Copyright 2009. Published by Elsevier GmbH.
Markus K Diener; Alexis Ulrich; Theresia Weber; Moritz N Wente; Markus W Büchler; Helmut Friess
AIM: To present a case of methicillin-resistant Staphylococcus aureus (MRSA) infection following bile duct stenting in a patient with malignant biliary obstruction.METHODS: A 78-year-old male patient was admitted to a community hospital with progredient painless jaundice lasting over two weeks, weight loss and sweating at night.Whether a stent should be implanted pre-operatively in jaundiced patients or whether these patients should directly undergo surgical resection, was discussed.RESULTS: ERC and a biopsy from the papilla of Vater revealed an adenocarcinoma. In addition, a 7-Ch plastic stent was placed into the common bile duct. Persistent abdominal pain, increasing jaundice, weakness and indigestion led to the transfer of the patient to our hospital.A pylorus-preserving pancreatoduodenectomy wasperformed. Intraoperatively, bile leaked out of the transected choledochus andthe stent was found to be dislocated in the duodenum. A smear of the bile revealed an infection with MRSA, leading to post-operative isolation of the patient.CONCLUSION:As biliary stents can cause severe infection of the bile, the need for pre-operative placement of biliary stents should be carefully evaluated in each individual case.
Shariq, Ali; Tanvir, Syed Bilal; Zaman, Atif; Khan, Salman; Anis, Armeena; Khan, Misha Aftab; Ahmed, Sumaira
Objective: To determine the resistance and sensitivity pattern of methicillin-resistant Staphylococcus aureus (MRSA) isolates to linezolid (LZD) along with its prevalence in a tertiary care hospital of Karachi, Pakistan. Materials and Methods: A cross-sectional study was carried out. This study lasted for about 1 year. Prevalence and sensitivity of LZD, vancomycin, and oxacillin was tested against isolates of MRSA. Results: Out of total 369 specimens 165 were found to be MRSA making the prevalence in our study 44.7%. All of the isolates which were tested positive for MRSA were susceptible to LZD and no resistance was noted when compared with previous studies performed in Europe and USA. Conclusion: Stringent implementation of infection control measures along with screening for resistance in patients on prolonged LZD therapy or who previously went under LZD therapy should be performed, coupled with judicious usage of the aforementioned antibiotic should be undertaken, as sufficient data is not available at this point for the clinical spectrum of LZD resistant S. aureus, antimicrobial resistance.
Woon, Colin Yl; Patel, Kushal R; Goldberg, Benjamin A
Gluteal compartment syndrome (GCS) is a rare condition. We present a case of gluteal muscle strain with hematoma formation, methicillin-resistant Staphylococcus aureus (MRSA) superinfection, leading to acute GCS, rhabdomyolysis and acute kidney injury. This combination of diagnoses has not been reported in the literature. A 36-year-old Caucasian male presented with buttock pain, swelling and fever after lifting weights. Gluteal compartment pressure was markedly elevated compared with the contralateral side. Investigations revealed elevated white blood cell, erythrocyte sedimentation rate, C-reactive protein, creatine kinase, creatinine and lactic acid. Urinalysis was consistent with myoglobinuria. Magnetic resonance imaging showed increased T2 signal in the gluteus maximus and a central hematoma. Cultures taken from the emergency debridement and fasciotomy revealed MRSA. He had repeat, debridement 2 d later, and delayed primary closure 3 d after. GCS is rare and must be suspected when patients present with pain and swelling after an inciting event. They are easily diagnosed with compartment pressure monitoring. The treatment of gluteal abscess and compartment syndrome is the same and involves rapid surgical debridement.
Davis, J S; Van Hal, S; Tong, S Y C
Outcomes from methicillin-resistant Staphylococcus aureus (MRSA) infections are relatively poor, at least in part due to the limitations of vancomycin (the current standard treatment for MRSA). Combination antibiotic treatment for MRSA infections is an attractive alternative as it could address most of vancomycin's shortcomings, including poor tissue penetration, slow bacterial killing, and emerging resistance in some strains of MRSA. However, the theoretical promise of combination therapy for MRSA infections has not been borne out in most in vitro and animal studies. Multiple combinations have been tested and have been either antagonistic, indifferent, or have had conflicting findings in various studies. This includes combinations of two primarily active agents (such as vancomycin plus daptomycin or linezolid), or the addition of gentamicin or rifampin to either vancomycin or daptomycin. However, hope on this front has come from an unexpected quarter. Although MRSA is by definition inherently resistant to nearly all β-lactam antibiotics, this class of drugs has consistently shown evidence of synergy with either daptomycin or vancomycin in over 25 separate in vitro studies, and a limited number of animal and human observational studies. However, there are currently insufficient data to recommend β-lactam combination therapy in routine clinical use. Results of current and planned randomized controlled trials of this strategy are awaited.
Full Text Available Purpose: It is necessary to define the problem of methicillin resistant Staphylococcus aureus (MRSA in every hospital to evolve control strategies. The objectives of this study were to determine factors influencing the persistence of MRSA in patients with hospital acquired infection and to identify alternate cost effective antibiotics. Methods: A six month study was carried out for 50 patients with MRSA infection. Treatment modalities and risk factors were determined by a preset protocol. Minimum inhibitory concentration of commonly used antibiotics was determined. Results: The risk factors were prolonged postoperative morbidity, prior antibiotic therapy and emergency admissions. Seventy percent of the isolates were from postoperative cases undergoing emergency surgeries. Isolation was highest during the second week of hospital stay. Emergency admissions had a significantly higher chance of early isolation. Prior treatment with multiple antibiotics in 38% was found to be another major risk factor. Ofloxacin was seen to be efficacious in a small percentage of cases. Rifampicin in combination with ofloxacin and clindamycin were found to be other good alternatives. Ofloxacin was found to be the cheapest and vancomycin the most expensive, for a full course of treatment. Conclusions: Minimizing risk factors and attention to alternate cost effective combination therapy may ease the problem of management of infections with MRSA.
Sallam, Khalid Ibrahim; Abd-Elghany, Samir Mohammed; Elhadidy, Mohamed; Tamura, Tomohiro
The emergence of livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) in food-producing animals is of increasing interest, raising questions about the presence of MRSA in food of animal origin and potential sources of transmission to humans via the food chain. In this study, the prevalence, molecular characterization, virulence factors, and antimicrobial susceptibility patterns of MRSA isolates from 200 retail raw chicken samples in Egypt were determined. MRSA was detected by positive amplification of the mecA gene in 38% (76 of 200) of chicken samples analyzed. This represents a potential public health threat in Egypt, as this contamination rate seems to be the highest among other studies reported worldwide. Furthermore, genes encoding α-hemolysin (hla) and staphylococcal enterotoxins (sea, seb, and sec) were detected in all of the 288 MRSA isolates. Nonetheless, none of the strains tested carried tst, the gene encoding toxic shock syndrome toxin 1. Antimicrobial resistance of MRSA isolates was most frequently detected against penicillin (93.4%), ampicillin (88.9%), and cloxacillin (83.3%). These results suggest that retail chicken might be a significant potential source for transmission of multidrug-resistant and toxigenic S. aureus in Egypt. This underlines the need for stricter hygienic measures in chicken production in Egypt to minimize the risk of transmission of these strains to consumers. To the best of our knowledge, this is the first study that reports the isolation and molecular characterization of MRSA in retail chicken samples in Egypt.
Obed, Mora; García-Vidal, Carolina; Pessacq, Pedro; Mykietiuk, Analia; Viasus, Diego; Cazzola, Laura; Domínguez, M Angeles; Calmaggi, Anibal; Carratalà, Jordi
The aim of this study is to describe the epidemiological and clinical features, treatment and prognosis of community-acquired pneumonia (CAP) caused by methicillin-resistant Staphylococcus aureus (MRSA) in two different geographic regions where community-acquired MRSA (CA-MRSA) infections have different frequencies. Observational study of patients admitted to two hospitals (one in Argentina, the other in Spain) between March 2008 and June 2012. We documented 16 cases of CAP caused by MRSA. MRSA accounted for 15 of 547 (2.7%) cases of CAP in Hospital Rodolfo Rossi and 1 of 1258 (0,08%) cases at the Hospital Universitari de Bellvitge (P ≤ .001). Most patients were young and previously healthy. Multilobar infiltrates, cavitation and skin and soft tissue involvement were frequent. All patients had positive blood cultures. Five patients required admission to the intensive care unit. Early mortality (≤ 48 hours) was 19%, and overall mortality (≤ 30 days) was 25%. CAP caused by MRSA causes high morbidity and mortality rates. It should be suspected in areas with a high prevalence of CA-MRSA infections, and especially in young and healthy patients who present with multilobar pneumonia with cavitation. Mortality is mainly related to septic shock and respiratory failure and occurs early in most cases. Copyright © 2012 Elsevier España, S.L. All rights reserved.
Warrack, S; Panjikar, P; Duster, M; Safdar, N
Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen of major public health importance. Colonisation precedes infection; thus reducing MRSA carriage may be of benefit for reducing infection. Probiotics represent a novel approach to reducing MRSA carriage. We undertook a pilot feasibility randomised controlled trial of the tolerability and acceptability of probiotics for reducing nasal and intestinal carriage of MRSA. In addition, subjects were screened for vancomycin-resistant enterocococci (VRE). Subjects with a history of MRSA were recruited from a large, academic medical center and randomised to take either a placebo or probiotic (Lactobacillus rhamnosus HN001). Subjects returned to the clinic after four weeks for further testing to determine adherence to the probiotic regimen and colonisation of MRSA. 48 subjects were enrolled and randomised. Nearly 25% were transplant recipients and 30% had diabetes. The probiotic was well tolerated in the study population though minor side effects, such as nausea and bloating, were observed. A majority of the subjects randomised to HN001 had good adherence to the regimen. At the four week time point among subjects randomised to the probiotic, MRSA was detected in 67 and 50% of subjects colonised in the nares and the gastrointestinal tract, respectively. Three subjects who initially tested positive for VRE were negative after four weeks of probiotic exposure. Probiotics were well tolerated in our study population of largely immunocompromised subjects with multiple comorbidities. Adherence to the intervention was good. Probiotics should be studied further for their potential to reduce colonisation by multidrug resistant bacteria.
Hend M. Abdulghany
Full Text Available The current study aimed to use Coagulase gene polymorphism to identify methicillin-resistant Staphylococcus aureus (MRSA subtypes isolated from nasal carriers in Minia governorate, Egypt, evaluate the efficiency of these methods in discriminating variable strains, and compare these subtypes with antibiotypes. A total of 400 specimens were collected from nasal carriers in Minia governorate, Egypt, between March 2012 and April 2013. Fifty-eight strains (14.5% were isolated and identified by standard microbiological methods as MRSA. The identified isolates were tested by Coagulase gene RFLP typing. Out of 58 MRSA isolates 15 coa types were classified, and the amplification products showed multiple bands (1, 2, 3, 4, 5, and 8 bands. Coagulase gene PCR-RFLPs exhibited 10 patterns that ranged from 1 to 8 fragments with AluI digestion. Antimicrobial susceptibility testing with a panel of 8 antimicrobial agents showed 6 different antibiotypes. Antibiotype 1 was the most common phenotype with 82.7%. The results have demonstrated that many new variants of the coa gene are present in Minia, Egypt, different from those reported in the previous studies. So surveillance of MRSA should be continued.
Athanasopoulos, A; Devogel, P; Beken, C; Pille, C; Bernier, I; Gavage, P
Rapid detection of Methicillin-Resistant Staphylococcus aureus (MRSA) is of major importance in hospital hygiene. In order to reduce the response time from screening laboratories, new selective chromogenic media have been developed and marketed by major microbiology companies. In this context, an evaluation of their performances was needed. Media produced by Bio-Rad Laboratories (MRSASelect), Becton Dickinson (CHROMagar MRSA) and bioMérieux (chromID MRSA) were studied by 203screening samples, 110 of which were MRSA positive. Each Stahylococcus aureus was identified by catalase detection, Staphytect Plus Dryspot latex agglutination test and free coagulase detection, in addition to mannitol fermentation and Voges-Proskauer tests in the case of doubtful identification. Resistance was verified by checking the inhibition zone diameter of under 20 mm on 30 microg cefoxitin disks. Bio-Rad Laboratories, Becton Dickinson and bioMérieux media read at 24 or 24/48 hours have a respective sensitivity of 91, 71 and 85/92%. The specificity of these media is 99, 100 and 99/93%. These media proved to be new powerful and rapid tools used in screening for MRSA detection. MRSASelect is one of the most effective media showing high sensitivity and specificity and the easiest interpretation. chromID MRSA exhibits similar performance but needs more time to be as effective as Bio-Rad media while CHROMagar MRSA isn't enough efficient with its slightly lack of sensitivity to perform a reliable screening.
Kraushaar, Britta; Fetsch, Alexandra
Staphylococcus aureus is an important food-borne pathogen due to the ability of enterotoxigenic strains to produce staphylococcal enterotoxins (SEs) in food. Methicillin-resistant S. aureus (MRSA) is also an important pathogen for humans, causing severe and hard to treat diseases in hospitals and in the community due to its multiresistance against antimicrobials. In particular, strains harbouring genes encoding for the Panton-Valentine leukocidin (PVL) toxin are of concern from a public health perspective as they are usually capable of causing severe skin and soft tissue infections (sSSTIs) and occasionally necrotizing pneumonia which is associated with high mortality. This is the first report on the detection of MRSA with genes encoding for PVL in wild boar meat. Among the 28 MRSA isolated from wild boar meat in the course of a national monitoring programme in Germany, seven harboured PVL-encoding genes. Six of the isolates were identical according to the results of spa-, MLST-, microarray- and PFGE-typing. They could be assigned to the epidemic MRSA clone USA300. Epidemiological investigations revealed that people handling the food were the most likely common source of contamination with these MRSA. These findings call again for suitable hygienic measures at all processing steps of the food production chain. The results of the study underline that monitoring along the food chain is essential to closely characterise the total burden of MRSA for public health.
Full Text Available Skin and chronic wound infections caused by highly antibiotic resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA are an increasing and urgent health problem worldwide, particularly with sharp increases in obesity and diabetes. New Zealand manuka honey has potent broad-spectrum antimicrobial activity, has been shown to inhibit the growth of MRSA strains, and bacteria resistant to this honey have not been obtainable in the laboratory. Combinational treatment of chronic wounds with manuka honey and common antibiotics may offer a wide range of advantages including synergistic enhancement of the antibacterial activity, reduction of the effective dose of the antibiotic, and reduction of the risk of antibiotic resistance. The aim of this study was to investigate the effect of Medihoney in combination with the widely used antibiotic rifampicin on S. aureus. Using checkerboard microdilution assays, time-kill curve experiments and agar diffusion assays, we show a synergism between Medihoney and rifampicin against MRSA and clinical isolates of S. aureus. Furthermore, the Medihoney/rifampicin combination stopped the appearance of rifampicin-resistant S. aureus in vitro. Methylglyoxal (MGO, believed to be the major antibacterial compound in manuka honey, did not act synergistically with rifampicin and is therefore not the sole factor responsible for the synergistic effect of manuka honey with rifampicin. Our findings support the idea that a combination of honey and antibiotics may be an effective new antimicrobial therapy for chronic wound infections.
Cadena, Jose; Sreeramoju, Pranavi; Nair, Shalini; Henao-Martinez, Andres; Jorgensen, James; Patterson, Jan E
In this prospective, observational study of 618 consecutive adult patients with skin and soft tissue infections (SSTI) caused by methicillin-resistant Staphylococcus aureus (MRSA), the clinical characteristics, molecular epidemiology, and outcome of patients with clindamycin-resistant MRSA (n = 64) and clindamycin-susceptible MRSA (n = 554) were compared (including factors predictive of clindamycin-resistant MRSA SSTI). Patients with clindamycin-resistant MRSA were more likely to have had antibiotic exposure within 3 months (37.5% versus 17%, P < 0.01), surgery (25% versus 8%, P < 0.01), MRSA infection/colonization within 12 months (23% versus 7%, P < 0.01), or intravascular catheters (5% versus 0.5%, P = 0.02). On multivariate analysis, previous surgery (adjusted odds ratio [AOR] 2.97; 95% confidence interval [CI] 1.5-6.0), history of MRSA (AOR 3.4; 95% CI 1.7-7.1), and exposure to clindamycin (AOR 8.5; 95% CI 2.3-32) and to macrolides (AOR 7.2, 95% CI 1.6-31.8) were independently associated with presence of clindamycin-resistant MRSA. Clinical resolution was similar between groups (77% versus 68%; P = 0.26). Clindamycin-resistant MRSA was less often USA-300 (82% versus 98%, P = 0.004). Clindamycin resistance did not affect MRSA-SSTI clinical outcomes.
In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements.
Kizerwetter-Świda, Magdalena; Chrobak-Chmiel, Dorota; Rzewuska, Magdalena; Binek, Marian
We investigated in vitro activity of a novel veterinary fluoroquinolone, pradofloxacin, against methicillin-resistant Staphylococcus pseudintermedius (MRSP) isolates and compared with other fluoroquinolones. A total of 38 MRSP isolates were subjected to agar disk diffusion tests for sensitivity to pradofloxacin, orbifloxacin, marbofloxacin, enrofloxacin, and ciprofloxacin. The minimal inhibitory concentration (MIC) values of pradofloxacin, ciprofloxacin, and enrofloxacin were determined. Mutations in the genes encoding DNA gyrase subunit A (GyrA) and topoisomerase IV (GrlA) proteins associated with fluoroquinolone resistance were studied by an analysis of partial sequences of the genes encoding these proteins. Two MRSP isolates were susceptible in disk diffusion and microdilution test to all fluoroquinolones tested, including pradofloxacin. Based on the results of the disk diffusion testing, 33 of 38 isolates showed resistance to pradofloxacin and 3 were intermediate, whereas, by pradofloxacin MIC testing, 35 isolates were classified as resistant and 1 as intermediate. Single alterations in GyrA and GrlA proteins were observed in the 35 resistant isolates and the 1 intermediate isolate (MIC results). These same 36 isolates were also resistant to the other tested fluoroquinolones. The results of the current study showed that MRSP isolates are usually resistant to all fluoroquinolones, including pradofloxacin. Therefore, in routine susceptibility testing to pradofloxacin by disk diffusion, the results should be carefully interpreted for MRSP isolates, especially those resistant to other fluoroquinolones and, in questionable cases, the pradofloxacin MIC should be determined to confirm the susceptibility testing results. © 2016 The Author(s).
Cao, Huiliang; Qin, Hui; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Meng, Fanhao; Zhang, Xianlong; Liu, Xuanyong
Since the use of systemic antibiotics for preventing acute biomaterial-associated infections (BAIs) may build up bacterial resistance and result in huge medical costs and unpredictable mortality, new precaution strategies are required. Here, it demonstrated that titanium armed with a nano-thick calcium oxide layer was effective on averting methicillin-resistant Staphylococcus aureus (MRSA) infections in rabbits. The calcium oxide layer was constructed by, firstly, injecting of metallic calcium into titanium via a plasma immersion ion implantation process, and then transforming the outer most surface into oxide by exposing to the atmosphere. Although the calcium oxide armed titanium had a relative low reduction rate (~74%) in growth of MRSA in vitro, it could markedly promote the osteogenic differentiation of bone marrow stem cells (BMSCs), restore local bone integration against the challenge of MRSA, and decrease the incidence of MRSA infection with a rate of 100% (compared to the titanium control). This study demonstrated for the first time that calcium, as one of the major elements in a human body, could be engineered to avert MRSA infections, which is promising as a safe precaution of disinfection for implantable biomedical devices.
F.C. de Sousa-Junior
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA is a major agent of hospital infections worldwide. In Brazil, a multiresistant MRSA lineage (ST239-SCCmecIIIA, the so-called Brazilian epidemic clone (BEC, has predominated in all regions. However, an increase in nosocomial infections caused by non-multiresistant MRSA clones has recently been observed. In the present study, 45 clinical isolates of MRSA obtained from a university hospital located in Natal city, Brazil, were identified by standard laboratory methods and molecularly characterized using staphylococcal chromosome cassette mec (SCCmec typing and pulsed-field gel electrophoresis. Antimicrobial susceptibility testing was carried out using CLSI methods. The MRSA isolates studied displayed a total of 8 different pulsed-field gel electrophoresis patterns (types A to H with predominance (73% of pattern A (BEC-related. However, MRSA harboring SCCmec type IV were also identified, 3 (7% of which were genetically related to the pediatric clone - USA800 (ST5-SCCmecIV. In addition, we found a considerable genetic diversity within BEC isolates. MRSA displaying SCCmecIV are frequently susceptible to the majority of non-β-lactam antibiotics. However, emergence of multiresistant variants of USA800 was detected.
Monecke, Stefan; Coombs, Geoffrey; Shore, Anna C.; Coleman, David C.; Akpaka, Patrick; Borg, Michael; Chow, Henry; Ip, Margaret; Jatzwauk, Lutz; Jonas, Daniel; Kadlec, Kristina; Kearns, Angela; Laurent, Frederic; O'Brien, Frances G.; Pearson, Julie; Ruppelt, Antje; Schwarz, Stefan; Scicluna, Elizabeth; Slickers, Peter; Tan, Hui-Leen; Weber, Stefan; Ehricht, Ralf
In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements. PMID:21494333
Full Text Available In recent years, methicillin-resistant Staphylococcus aureus (MRSA have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements.
Benedito Prado Dias Filho
Full Text Available Piper regnellii (Miq. C. DC. var. pallescens (C. DC. Yunck (Piperaceae is a medicinal plant traditionally used in Brazil to treat infectious diseases. The extracts obtained of the leaves from P. regnellii were investigated for their antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA. The ethyl acetate extract presented a good activity against MRSA, with minimal inhibitory concentration (MIC and minimal bactericidal concentration (MBC of 16 μg/mL. Based on this finding, the ethyl acetate extract was fractionated by silica gel column chromatography into nine fractions. The hexane fraction was active against MRSA (MIC at 4 μg/mL. Further column chromatography separation of the hexane fraction afforded the pure compound eupomatenoid-5. The structure of the compound was established by spectral data (1H and 13C NMR HSQC, HMBC, gNOE, IR and MS. Eupomatenoid-5 was the only compound active on the bacterium. The antibacterial property of P. regnellii extract provides preliminary scientific validation for the traditional medicinal use of this plant. The active compound eupomatenoid-5 should be further studied in animal models to verify in vivo efficacy and toxicity.
Rivero-Pérez, Belinda; Alcoba-Flórez, Julia; Méndez-Álvarez, Sebastián
With the recent detection of MRSA (methicillin-resistant Staphylococcus aureus) infections in patients lacking health care-related risk factors, the term community-acquired MRSA (CA-MRSA) has been become widely recognised. Many cases of CA-MRSA spreading to the community have been described worldwide. The aim of this study was to determine the features of CA-MRSA isolates from Tenerife Island. Toward this end, one hundred MRSA isolates were collected from eight different health regions, and their molecular features were investigated. This study revealed a wide variety of MRSA clones, including an emergent ST: ST1434 (CC8) and two new spa types, t7575 (ST125) and t7678 (ST22). The PVL genes were found in only five isolates belonging to unrelated lineages, ST8, ST30 and ST22, which could indicate at least three independent introductions of PVL(+) strains to Tenerife. Moreover, we detected that hospital MRSA clones, like EMRSA-15 and EMRSA-16, had spread to the community and are now circulating in both environments. Therefore, in our study, the CDC's rules were not specific enough to distinguish CA-MRSA from HA-MRSA. Thus, we think that the current epidemiological information is not enough to discriminate between both MRSAs, and it is necessary for prevention guidelines to include the routine determination of at least the genetic background, the antimicrobial susceptibility profile, and the PVL genes of each MRSA isolate.
Full Text Available Background: Methicillin-resistant Staphylococcus aureus (MRSA is a major nosocomial pathogen. Indiscriminate and increased use of systemic antibiotics has led to the emergence of MRSA. Infected or colonized ward patients are the main reservoir of infection. Once colonized, the risk of subsequent local and systemic infections is high, especially in the elderly, and in debilitated and immunosuppressed patients. Methods: We report an outbreak of MRSA in the dermatology ward of a tertiary care hospital and describe measures taken to control it. Results: Ten patients were found to be MRSA positive over a span of three months while screening swabs from wet lesions in indoor patients. On the basis of risk assessment, they were treated with appropriate systemic and topical therapy. One patient died while the remaining nine patients showed a good response to therapy. All the MRSA isolates were found to be sensitive to vancomycin, teicoplanin and linezolid. Conclusion: This is the first case report of MRSA infection in dermatology indoor patients in India.
Bühlmann, Manuela; Bögli-Stuber, Katja; Droz, Sara; Mühlemann, Kathrin
PCR tests for the rapid and valid detection of methicillin-resistant Staphylococcus aureus (MRSA) are now available. We evaluated the costs associated with contact screening for MRSA carriage in a tertiary-care hospital with low MRSA endemicity. Between 1 October 2005 and 28 February 2006, 232 patients were screened during 258 screening episodes (644 samples) for MRSA carriage by GenoType MRSA Direct (Hain Lifescience GmbH, Nehren, Germany). Conventional culture confirmed all PCR results. According to in-house algorithms, 34 of 258 screening episodes (14.7%) would have qualified for preemptive contact isolation, but such isolation was not done upon negative PCR results. MRSA carriage was detected in 4 (1.5%) of 258 screening episodes (i.e., in four patients), of which none qualified for preemptive contact isolation. The use of PCR for all 258 screening episodes added costs (in Swiss francs [CHF]) of CHF 104,328.00 and saved CHF 38,528.00 (for preemptive isolation). The restriction of PCR screening to the 34 episodes that qualified for preemptive contact isolation and screening all others by culture would have lowered costs for PCR to only CHF 11,988.00, a savings of CHF 38,528.00. Therefore, PCR tests are valuable for the rapid detection of MRSA carriers, but high costs require the careful evaluation of their use. In patient populations with low MRSA endemicity, the broad use of PCR probably is not cost-effective.
Alaa Al Amiry
Methicillin-resistantStaphylococcus aureus (MRSA) is a serious nosocomial infection within healthcare settings, and with its community version worldwide (i.e. community-acquired-MRSA), it is safe now to classify it as an epidemic. The aim of this paper is to build the logic for the reader to understand why this drug-resistant infection can impose an occupational hazard towards emergency health services personnel in the prehospital settings. This logic started with a model, the author conceptualizes as a cross-transmission continuum, in which the author explains the role of emergency medical service personnel in possibly contributing to the transmission of MRSA back and forth the community. A solution to interrupt this continuum, particularly surveillance systems within the emergency medical service field, is suggested and discussed. This is especially important in the light of bioterrorism as surveillance can become a necessity in preparation for biological disasters whether they are intentional (i.e. bioterrorism) or natural (i.e. outbreaks).
Full Text Available We developed, tested, and applied a TaqMan real-time PCR assay for interrogation of three single-nucleotide polymorphisms that differentiate a clade (termed 't003-X' within the radiation of methicillin-resistant Staphylococcus aureus (MRSA ST225. The TaqMan assay achieved 98% typeability and results were fully concordant with DNA sequencing. By applying this assay to 305 ST225 isolates from an international collection, we demonstrate that clade t003-X is endemic in a single acute-care hospital in Germany at least since 2006, where it has caused a substantial proportion of infections. The strain was also detected in another hospital located 16 kilometers away. Strikingly, however, clade t003-X was not found in 62 other hospitals throughout Germany nor among isolates from other countries, and, hence, displayed a very restricted geographical distribution. Consequently, our results show that SNP-typing may be useful to identify and track MRSA clones that are specific to individual healthcare institutions. In contrast, the spatial dissemination pattern observed here had not been resolved by other typing procedures, including multilocus sequence typing (MLST, spa typing, DNA macrorestriction, and multilocus variable-number tandem repeat analysis (MLVA.
Cheng, Nai-Chen; Wang, Jann-Tay; Chang, Shan-Chwen; Tai, Hao-Chih; Tang, Yueh-Bih
Staphylococcus aureus is an uncommon causative agent of monomicrobial necrotizing fasciitis, but we have noted several cases over the years. The patients treated for necrotizing fasciitis between January 1998 and December 2008 in our institution were identified, and their medical records were reviewed. Of 105 necrotizing fasciitis cases during the study period, 18 were caused by monomicrobial S. aureus infection (17%). The median age was 62 years (range, 12-81 years). Among this cohort, 10 patients had coexisting medical conditions or risk factors, including diabetes and hypertension. Lower limbs and upper limbs are the most commonly involved sites. Among the bacterial isolates from these cases, 8 were methicillin-sensitive S. aureus (MSSA) and 10 were methicillin-resistant S. aureus (MRSA). One patient died in the MSSA group, and 5 patients died in the MRSA group. The mortality rate and other clinical characteristics were not significantly different between the 2 groups. However, all MRSA necrotizing fasciitis developed after the year 2000, and it was significantly different from MSSA necrotizing fasciitis that predominantly took place before the year 2000. In conclusion, S. aureus is an important pathogen of monomicrobial necrotizing fasciitis, and MRSA has emerged as the predominant causative agent in recent years. Therefore, MRSA-directed antibiotic therapy should be considered when treating patients suspected with necrotizing fasciitis in endemic areas.
Full Text Available Purpose: We report a case of methicillin-resistant Staphylococcus aureus (MRSA keratitis after Descemet's stripping automated endothelial keratoplasty (DSAEK. Case Report: An 87-year-old woman who had undergone a DSAEK 4 months previously was referred to Tokushima University Hospital with a diagnosis of infectious keratitis after DSAEK. A white abscess and infiltration in the inferior cornea of the right eye were observed. We started an empiric therapy using topical levofloxacin and chloramphenicol on the basis of the microscopic findings of the corneal scraping concurrently with cultivation of the cornea. Results: A strain of MRSA was isolated from the corneal sample. Although the strain was susceptible to chloramphenicol, it was resistant to quinolone. The keratitis improved rapidly due to empiric therapy, and topical steroids could be resumed 6 days after initiation of the empiric therapy. Conclusions: To our knowledge, this is the first case of MRSA keratitis, and the second case of bacterial keratitis, after DSAEK. MRSA keratitis can occur following uneventful DSAEK. The empiric therapy on the basis of results from a light microscopic examination of a Gram-stained corneal scraping and restarting topical steroids in the early stages of medication contributed to the good clinical course of this case.
Campbell, Jonathan A; Dickson, James S; Cordray, Joseph C; Olson, Dennis G; Mendonca, Aubrey F; Prusa, Kenneth J
Infections from antibiotic-resistant bacteria are a major concern for human health professionals around the world. Methicillin-resistant Staphylococcus aureus (MRSA) is just one of the resistant organisms of concern. MRSA prevalence has also been recently reported in retail meat products at rates higher than originally thought. Although the risk of contracting an infection from handling contaminated meat products is thought to be low, very little is known about this organism from a food safety perspective. The objective of this study was to determine the survival of MRSA during thermal processing of frankfurters, summer sausage, and boneless ham. Frankfurters, summer sausage, and boneless ham were manufactured using formulations and processing procedures developed at the Iowa State University meat laboratory. Thermal processing resulted in a significant log reduction (psausage, and frankfurters when compared to uncooked, positive controls for each of the three processed meat products. All products were thermally processed to an internal temperature of 70°C and promptly cooled to 7.2°C. Boneless ham showed the highest log reduction (7.28 logs) from cooking, followed by summer sausage (6.75 logs) and frankfurters (5.53 logs). The results of this study indicate that thermal processing of ham, summer sausage, and frankfurters to 70°C is sufficient to reduce the risk of MRSA as a potential food safety hazard.
Christianson, Sara; Golding, George R.; Campbell, Jennifer; Mulvey, Michael R.
Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen that has disseminated throughout Canadian hospitals and communities. Pulsed-field gel electrophoresis of over 9,300 MRSA isolates obtained from the Canadian Nosocomial Infection Surveillance Program has identified 10 epidemic strain types in Canada (CMRSA1 to CMRSA10). In an attempt to determine specific genetic factors that have contributed to their high prevalence in community and/or hospital settings, the genomic content of representative isolates for each of the 10 Canadian epidemic types was compared using comparative genomic hybridizations. Comparison of the community-associated Canadian epidemic isolates (CMRSA7 and CMRSA10) with the hospital-associated Canadian epidemic isolates revealed one open reading frame (ORF) (SACOL0046) encoding a putative protein belonging to a metallo-beta-lactamase family, which was present only in the community-associated Canadian epidemic isolates. A more restricted comparison involving only the most common hospital-associated Canadian epidemic isolates (CMRSA1 and CMRSA2) with the community-associated Canadian epidemic isolates did reveal additional factors that might be contributing to their prevalence in the community and hospital settings, which included ORFs encoding potential virulence factors involved in capsular biosynthesis, serine proteases, epidermin, adhesion factors, regulatory functions, leukotoxins, and exotoxins. PMID:17428941
Bueso-Bordils, Jose I; Perez-Gracia, Maria T; Suay-Garcia, Beatriz; Duart, Maria J; Martin Algarra, Rafael V; Lahuerta Zamora, Luis; Anton-Fos, Gerardo M; Aleman Lopez, Pedro A
Molecular topology was used to develop a mathematical model capable of classifying compounds according to antimicrobial activity against methicillin resistant Staphylococcus aureus (MRSA). Topological indices were used as structural descriptors and their relation to antimicrobial activity was determined by using linear discriminant analysis. This topological model establishes new structure activity relationships which show that the presence of cyclopropyl, chlorine and ramification pairs at a distance of two bonds favor this activity, while the presence of tertiary amines decreases it. This model was applied to a combinatorial library of a thousand and one 6-fluoroquinolones, from which 117 theoretical active molecules were obtained. The compound 10 and five new quinolones were tested against MRSA. They all showed some activity against MRSA, although compounds 6, 8 and 9 showed anti-MRSA activity similar to ciprofloxacin. This model was also applied to 263 theoretical antibacterial agents described by us in a previous work, from which 34 were predicted as theoretically active. Anti-MRSA activity was found bibliographically in 9 of them (ensuring at least 26% of success), and from the rest, 3 compounds were randomly chosen and tested, finding mitomycin C to be more active than ciprofloxacin. The results demonstrate the utility of the molecular topology approaches for identifying new drugs active against MRSA. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
Peyrani, P; Allen, M; Seligson, D; Roberts, C; Chen, A; Haque, N; Zervos, M; Wiemken, T; Harting, J; Christensen, D; Ramirez, R
Methicillin-resistant Staphylococcus aureus (MRSA) USA-300 strains have emerged as an important cause of community-acquired infections. These strains have been recognized as an etiology of osteomyelitis but data on their incidence and outcomes are limited. We retrospectively studied the incidence and clinical outcomes of MRSA USA-300 osteomyelitis in patients at the University of Louisville Hospital and the Henry Ford Health System between January 2007 and March 2008. Pulsed-field gel electrophoresis was used to determine USA type. Clinical outcomes were defined as management success versus failure at 12 months. Chi-square tests, Fisher exact tests, and Mann-Whitney tests were used to compare patient characteristics on the basis of clinical outcomes and USA type. Of the 50 patients with MRSA osteomyelitis, 27 (54%) had the USA-300 strain. Clinical failure was identified in 22% (6/27) of the patients with MRSA USA-300 and in 30% (7/23) of the patients with MRSA non-USA-300 osteomyelitis (P = .509). Our results showed that MRSA USA-300 is a significant etiology of MRSA osteomyelitis. With current surgical and medical management, outcomes of patients with MRSA USA-300 osteomyelitis are similar to those of patients with MRSA non-USA-300 osteomyelitis.
Monecke, Stefan; Coombs, Geoffrey; Shore, Anna C; Coleman, David C; Akpaka, Patrick; Borg, Michael; Chow, Henry; Ip, Margaret; Jatzwauk, Lutz; Jonas, Daniel; Kadlec, Kristina; Kearns, Angela; Laurent, Frederic; O'Brien, Frances G; Pearson, Julie; Ruppelt, Antje; Schwarz, Stefan; Scicluna, Elizabeth; Slickers, Peter; Tan, Hui-Leen; Weber, Stefan; Ehricht, Ralf
In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements.
Many countries have national guidelines for the prevention and control of methicillin-resistant Staphylococcus aureus (MRSA) that are similar in approach. The evidence base for many recommendations is variable, and often, in the drafting of such guidelines, the evidence is either not analysed or not specifically reviewed. Guidelines usually recommend screening and early detection, hand hygiene, patient isolation or cohorting, and decolonization. Although many components of a prevention and control programme appear to be self-evident, e.g. patient isolation, the scientific base underpinning these is poor, and scientifically rigorous studies are required. Nonetheless, where measures, based on what evidence there is and on common sense, are implemented, and where the necessary resources are provided, MRSA can be controlled. In The Netherlands and in other low-prevalence countries, these measures have largely kept healthcare facilities MRSA-free. In MRSA-endemic countries, such as Spain and Ireland, national guidelines are often not fully implemented, owing to apparently inadequate resources or a lack of will. However, recent studies from France and Australia demonstrate what is possible in high-prevalence countries when best practice is effectively implemented, with potentially major benefits for patients, the respective health services, and society.
Huda A Bukharie
Full Text Available Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA infections among young people without healthcare-associated risk factors have emerged during the past decade. Reported prevalence rates of CA-MRSA vary widely among studies, largely because of the different definitions employed and different settings in which the studies have been performed. Although the majority of CA-MRSA infections are mild skin and soft tissue infections, severe life-threatening cases have been reported. CA-MRSA infections have mostly been associated with staphylococcal strains bearing the staphylococcal cassette chromosome mec type IV element and Panton-Valentine leukocidin genes. These strains are more frequently susceptible to a variety of non-beta-lactam antibiotics. Clinicians must be aware of the wide spectrum of disease caused by CA-MRSA. Continued emergence of MRSA in the community is a public health problem, and therefore warrants increased vigilance in the diagnosis and management of suspected and confirmed staphylococcal infections.
Calderwood, Michael S.; Desjardins, Christopher A.; Sakoulas, George; Nicol, Robert; DuBois, Andrea; Delaney, Mary L.; Kleinman, Ken; Cosimi, Lisa A.; Feldgarden, Michael; Onderdonk, Andrew B.; Birren, Bruce W.; Platt, Richard; Huang, Susan S.
Background. Methicillin-resistant Staphylococcus aureus (MRSA) colonization predicts later infection, with both host and pathogen determinants of invasive disease. Methods. This nested case-control study evaluates predictors of MRSA bacteremia in an 8–intensive care unit (ICU) prospective adult cohort from 1 September 2003 through 30 April 2005 with active MRSA surveillance and collection of ICU, post-ICU, and readmission MRSA isolates. We selected MRSA carriers who did (cases) and those who did not (controls) develop MRSA bacteremia. Generating assembled genome sequences, we evaluated 30 MRSA genes potentially associated with virulence and invasion. Using multivariable Cox proportional hazards regression, we assessed the association of these genes with MRSA bacteremia, controlling for host risk factors. Results. We collected 1578 MRSA isolates from 520 patients. We analyzed host and pathogen factors for 33 cases and 121 controls. Predictors of MRSA bacteremia included a diagnosis of cancer, presence of a central venous catheter, hyperglycemia (glucose level, >200 mg/dL), and infection with a MRSA strain carrying the gene for staphylococcal enterotoxin P (sep). Receipt of an anti-MRSA medication had a significant protective effect. Conclusions. In an analysis controlling for host factors, colonization with MRSA carrying sep increased the risk of MRSA bacteremia. Identification of risk-adjusted genetic determinants of virulence may help to improve prediction of invasive disease and suggest new targets for therapeutic intervention. PMID:24041793
Lassok, Birgit; Tenhagen, Bernd-Alois
Methicillin-resistant Staphylococcus aureus (MRSA) is a major global public health concern and could be a food safety issue. Recurrent reports have documented that pig herds are an important reservoir for MRSA, specifically the livestock-associated sequence type 398. The high prevalence of MRSA in pig primary production facilities and the frequent detection of MRSA of the same types in pork and pig meat products raise the question of underlying mechanisms behind the introduction and transmission of MRSA along the pork production chain. A comprehensive review of current literature on the worldwide presence of livestock-associated MRSA in various steps of the pork production chain revealed that the slaughter process plays a decisive role in MRSA transmission from farm to fork. Superficial heat treatments such as scalding and flaming during the slaughter process can significantly reduce the burden of MRSA on the carcasses. However, recontamination with MRSA might occur via surface treating machinery, as a result of fecal contamination at evisceration, or via increased human handling during meat processing. By optimizing processes for carcass decontamination and avoiding recontamination by effective cleaning and personal hygiene management, transmission of MRSA from pig to pork can be minimized.
Ferrara, Anna M
Nosocomial pneumonia and ventilator-assisted pneumonia may be polymicrobial and can be caused by a wide spectrum of pathogens. Potentially multidrug-resistant microorganisms often represent the 'core' pathogens of the most severe infections. Among Gram-positive pathogens, methicillin-resistant Staphylococcus aureus (MRSA) plays a key role, mainly in mechanically ventilated patients or in patients with specific risk factors. The mainstay of treatment for MRSA pneumonia has been glycopeptide antibiotics, i.e. vancomycin and, to a lesser extent, teicoplanin. However, owing to its insufficient penetration into lung compartments, vancomycin may result in therapeutic failure or slow clinical responses. Moreover, vancomycin serum levels must be monitored in order to minimise nephrotoxicity and to maximise the concentration in the lung. Finally, the emergence of staphylococci isolates with reduced susceptibility to vancomycin suggests that glycopeptides should no longer be considered as first-line antibacterial agents for Gram-positive lung infections. Among new therapeutic options, linezolid may be an appropriate choice for MRSA pulmonary infections owing to its good pharmacokinetic profile in the lung and its acceptable tolerability, especially in patients with renal insufficiency or in those receiving other nephrotoxic agents. However, to contain the increasing emergence of drug resistance among hospitalised patients, these novel antimicrobial agents should be used judiciously, restricting their use to patients not responsive to, or intolerant of, glycopeptides. Other new drugs under development appear to be promising and deserve further evaluation.
Haste, Nina M; Thienphrapa, Wdee; Tran, Dan N; Loesgen, Sandra; Sun, Peng; Nam, Sang-Jip; Jensen, Paul R; Fenical, William; Sakoulas, George; Nizet, Victor; Hensler, Mary E
The rapid rise in antimicrobial resistance in bacteria has generated an increased demand for the development of novel therapies to treat contemporary infections, especially those caused by methicillin-resistant Staphylococcus aureus (MRSA). However, antimicrobial development has been largely abandoned by the pharmaceutical industry. We recently isolated the previously described thiopeptide antibiotic nosiheptide from a marine actinomycete strain and evaluated its activity against contemporary clinically relevant bacterial pathogens. Nosiheptide exhibited extremely potent activity against all contemporary MRSA strains tested including multiple drug-resistant clinical isolates, with MIC values 0.25 mg l(-1). Nosiheptide was also highly active against Enterococcus spp. and the contemporary hypervirulent BI/NAP1/027 strain of Clostridium difficile but was inactive against most Gram-negative strains tested. Time-kill analysis revealed nosiheptide to be rapidly bactericidal against MRSA in a concentration- and time-dependent manner, with a nearly 2-log kill noted at 6 h at 10 × MIC. Furthermore, nosiheptide was found to be non-cytotoxic against mammalian cells at >100 × MIC, and its anti-MRSA activity was not inhibited by 20% human serum. Notably, nosiheptide exhibited a significantly prolonged post-antibiotic effect against both healthcare- and community-associated MRSA compared with vancomycin. Nosiheptide also demonstrated in vivo activity in a murine model of MRSA infection, and therefore represents a promising antibiotic for the treatment of serious infections caused by contemporary strains of MRSA.
de Moraes ACM
Full Text Available Ana Carolina Mazarin de Moraes,1 Bruna Araujo Lima,2 Andreia Fonseca de Faria,1 Marcelo Brocchi,2 Oswaldo Luiz Alves1 1Laboratory of Solid State Chemistry, Institute of Chemistry, University of Campinas, Campinas, São Paulo, Brazil; 2Department of Genetics, Evolution and Bioagents, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil Background: Methicillin-resistant Staphylococcus aureus (MRSA has been responsible for serious hospital infections worldwide. Nanomaterials are an alternative to conventional antibiotic compounds, because bacteria are unlikely to develop microbial resistance against nanomaterials. In the past decade, graphene oxide (GO has emerged as a material that is often used to support and stabilize silver nanoparticles (AgNPs for the preparation of novel antibacterial nanocomposites. In this work, we report the synthesis of the graphene-oxide silver nanocomposite (GO-Ag and its antibacterial activity against relevant microorganisms in medicine. Materials and methods: GO-Ag nanocomposite was synthesized through the reduction of silver ions (Ag+ by sodium citrate in an aqueous GO dispersion, and was extensively characterized using ultraviolet-visible absorption spectroscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. The antibacterial activity was evaluated by microdilution assays and time-kill experiments. The morphology of bacterial cells treated with GO-Ag was investigated via transmission electron microscopy. Results: AgNPs were well distributed throughout GO sheets, with an average size of 9.4±2.8 nm. The GO-Ag nanocomposite exhibited an excellent antibacterial activity against methicillin-resistant S. aureus, Acinetobacter baumannii, Enterococcus faecalis, and Escherichia coli. All (100% MRSA cells were inactivated after 4 hours of exposure to GO-Ag sheets. In addition, no toxicity was found for either pristine GO or bare Ag
The soluble copper silicate (CS) MIC of 100 strains of methicillin-resistant Staphylococcus aureus and 100 strains of methicillin-susceptible S. aureus (MSSA) was 175 mg Cu/liter. Bactericidal and postantibiotic effects (≥1 h) were seen at 2× MIC and 4× MIC. The frequency of mutation was
Mieke Hemiawati Satari
Full Text Available The aim of this study was to determine the molecular changing of S.aureus, which is resistant to Ampicillin-Sulbactam and then become resistant to Methicillin as a result of improper dosage. The study was conducted by isolating Ampicillin-Sulbactam resistant and Methicillin Resistant S.aureus (MRSA, afterwards an amplification process was performed by PCR (Polymerase Chain Reaction. to isolate the betalactamase enzyme regulator and PBP 2a genes. The result of this research showed that there were a deletion of few amino acids from the regulator gene, and a suspicion that the DNA sequence had been substituted from PBP 2 gene into PBP 2a (gen mec. This process had formed MRSA.
Bonde, Mette; Jacobsen, Kirstine; Kolmos, Hans Jørn
Few drugs are available against methicillin-resistant S. aureus (MRSA), and decreased susceptibility among staphylococci to newly introduced agents such as linezolid, daptomycin, and tigecycline has been observed [1-3]. Consequently, new treatment strategies are urgently needed. Thioridazine...
Chambers, Henry F
Ceftobiprole is a novel broad-spectrum cephalosporin that binds with high affinity to PBP 2a, the methicillin-resistance determinant of staphylococci, and is active against methicillin- and vancomycin-resistant Staphylococcus aureus. Ceftobiprole was compared to vancomycin in a rabbit model of methicillin-resistant S. aureus aortic valve endocarditis. Ceftobiprole and vancomycin were equally effective against endocarditis caused by methicillin-resistant S. aureus strain 76, whereas ceftobiprole was more effective than vancomycin against the vancomycin-intermediate S. aureus strain HIP5836. The activity of ceftobiprole against drug-resistant strains of S. aureus warrants its further clinical development.
Taneike, Ikue; Otsuka, Taketo; Dohmae, Soshi; Saito, Kohei; Ozaki, Kyoko; Takano, Misao; Higuchi, Wataru; Takano, Tomomi; Yamamoto, Tatsuo
Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) with Panton-Valentine leukocidin (PVL) genes is increasing worldwide. Nosocomial outbreak-derived (hospital-acquired) MRSA (HA-MRSA) in Japan in the 1980s was also largely PVL(+). PVL(+) HA-MRSA and CA-MRSA shared the same multi-locus sequence type (ST30) and methicillin resistance cassette (SCCmecIV), but were divergent in oxacillin resistance, spa typing, PFGE analysis or clfA gene analysis. PVL(+) HA-MRSA, which probably originated in PVL(+)S. aureus ST30, was highly adhesive (carrying cna and bbp genes), highly-toxic (carrying luk(PV) and sea genes) and highly drug-resistant. PVL(+) HA-MRSA was once replaced by other PVL(-) HA-MRSA (e.g., ST5), and is re-emerging as CA-MRSA.
Stewart, Audra; Dyamenahalli, Umesh; Greenberg, S Bruce; Drummond-Webb, Jonathan
We present the case of a 6-month-old previously healthy girl who presented with high fever, labored breathing, and an enlarged cardiac silhouette on her chest radiograph. Comprehensive evaluation discovered a ductus arteriosus aneurysm and pericardial effusion with methicillin-resistant Staphylococcus aureus bacteremia. Despite pericardiocentesis and appropriate intravenous antibiotics, there was rapid enlargement of the aneurysm and accumulation of echogenic material within the ductus arteriosus aneurysm. Infected aneurysm rupture was identified during emergency surgery. This infant also had vocal cord paresis, a likely complication of the surgery. The clinical course, diagnosis, and treatment of this patient are discussed. Infection of a ductus arteriosus or an infected ductal arteriosus aneurysm is a rare and potentially fatal clinical entity. In the era of increasing community-acquired methicillin-resistant S aureus infections, this is a diagnosis that requires a high index of suspicion.
Full Text Available Staphylococcus pseudintermedius is a commensal organism of companion animals that is a significant source of opportunistic infections in dogs. With the emergence of clinical isolates of S. pseudintermedius (chiefly methicillin-resistant S. pseudintermedius (MRSP exhibiting increased resistance to nearly all antibiotic classes, new antimicrobials and therapeutic strategies are urgently needed. Thiazole compounds have been previously shown to possess potent antibacterial activity against multidrug-resistant strains of Staphylococcus aureus of human and animal concern. Given the genetic similarity between S. aureus and S. pseudintermedius, this study explores the potential use of thiazole compounds as novel antibacterial agents against methicillin-sensitive S. pseudintermedius (MSSP and MRSP. A broth microdilution assay confirmed these compounds exhibit potent bactericidal activity (at sub-microgram/mL concentrations against both MSSA and MRSP clinical isolates while the MTS assay confirmed three compounds (at 10 μg/mL were not toxic to mammalian cells. A time-kill assay revealed two derivatives rapidly kill MRSP within two hours. However, this rapid bactericidal activity was not due to disruption of the bacterial cell membrane indicating an alternative mechanism of action for these compounds against MRSP. A multi-step resistance selection analysis revealed compounds 4 and 5 exhibited a modest (two-fold shift in activity over ten passages. Furthermore, all six compounds (at a subinihibitory concentration demonstrated the ability to re-sensitize MRSP to oxacillin, indicating these compounds have potential use for extending the therapeutic utility of β-lactam antibiotics against MRSP. Metabolic stability analysis with dog liver microsomes revealed compound 3 exhibited an improved physicochemical profile compared to the lead compound. In addition to this, all six thiazole compounds possessed a long post-antibiotic effect (at least 8 hours against
Mohammad, Haroon; Reddy, P V Narasimha; Monteleone, Dennis; Mayhoub, Abdelrahman S; Cushman, Mark; Hammac, G Kenitra; Seleem, Mohamed N
Staphylococcus pseudintermedius is a commensal organism of companion animals that is a significant source of opportunistic infections in dogs. With the emergence of clinical isolates of S. pseudintermedius (chiefly methicillin-resistant S. pseudintermedius (MRSP)) exhibiting increased resistance to nearly all antibiotic classes, new antimicrobials and therapeutic strategies are urgently needed. Thiazole compounds have been previously shown to possess potent antibacterial activity against multidrug-resistant strains of Staphylococcus aureus of human and animal concern. Given the genetic similarity between S. aureus and S. pseudintermedius, this study explores the potential use of thiazole compounds as novel antibacterial agents against methicillin-sensitive S. pseudintermedius (MSSP) and MRSP. A broth microdilution assay confirmed these compounds exhibit potent bactericidal activity (at sub-microgram/mL concentrations) against both MSSA and MRSP clinical isolates while the MTS assay confirmed three compounds (at 10 μg/mL) were not toxic to mammalian cells. A time-kill assay revealed two derivatives rapidly kill MRSP within two hours. However, this rapid bactericidal activity was not due to disruption of the bacterial cell membrane indicating an alternative mechanism of action for these compounds against MRSP. A multi-step resistance selection analysis revealed compounds 4 and 5 exhibited a modest (two-fold) shift in activity over ten passages. Furthermore, all six compounds (at a subinihibitory concentration) demonstrated the ability to re-sensitize MRSP to oxacillin, indicating these compounds have potential use for extending the therapeutic utility of β-lactam antibiotics against MRSP. Metabolic stability analysis with dog liver microsomes revealed compound 3 exhibited an improved physicochemical profile compared to the lead compound. In addition to this, all six thiazole compounds possessed a long post-antibiotic effect (at least 8 hours) against MRSP
Tang, Yi-Tong; Cao, Rui; Xiao, Na; Li, Zhi-Shan; Wang, Rong; Zou, Jiu-Ming; Pei, Jiao
Methicillin-resistant Staphylococcus aureus (MRSA) is a public health problem worldwide. This study aimed to investigate the antimicrobial susceptibilities and molecular epidemiological characteristics of MRSA strains in Xiangyang, China, during 2012-2014. Eighty non-duplicate S. aureus isolates from clinical specimens were collected from four tertiary hospitals. MRSA strains were identified and tested for antibacterial susceptibility. Staphylococcus cassette chromosome mec (SCCmec) typing, Pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST) and spa typing were performed to explore molecular characteristics. Forty-three MRSA strains were detected at a detection rate of 53.75%. MRSA strains exhibited resistance against non-β-lactam antibiotics at varying degrees. SCCmec III was the predominant type (39/43, 90.70%), and the rest were SCCmec IVa type (4, 9.30%). Thirteen types found in MLST were mainly ST239 (27.9%) and ST59 (16.27%). Fifteen types found in spa typing were mainly t437 (30.23%) and t030 (13.95%). PFGE grouped 43 MRSA isolates into five types. SCCmecIII-ST239-t030/t632 and SCCmec III-ST59/ST338-t437 were the dominant epidemic clones in this region. ST239-t030/t632/t037 were the epidemic clones with the most serious drug resistance. This region presented a high MRSA detection rate, and MRSA demonstrated strong antimicrobial resistance. The existence of four strains of community-acquired MRSA (SCCmec IVa type) induced the dissemination of MRSA strains from community to hospital. The epidemic situation and drug resistance of MRSA should be regularly monitored. Effective measures should be adopted to prevent and control the occurrence of infection in hospitals. Copyright © 2017. Published by Elsevier Ltd.
Holzknecht, B.J.; Hardardottir, H.; Haraldsson, Gustav Helgi;
and microbiological data of all MRSA patients from the years 2000 to 2008 were collected prospectively. Isolates were characterized by pulsed-field gel electrophoresis (PFGE), sequencing of the repeat region of the Staphylococcus protein A gene (spa typing), staphylococcal cassette chromosome mec (SCCmec) typing......The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) is continuously changing. Iceland has a low incidence of MRSA. A "search and destroy" policy (screening patients with defined risk factors and attempting eradication in carriers) has been implemented since 1991. Clinical...
Cartwright, Edward J. P.; Paterson, Gavin K.; Raven, Kathy E.; Harrison, Ewan M.; Gouliouris, Theodore; Kearns, Angela; Pichon, Bruno; Edwards, Giles; Skov, Robert L.; Larsen, Anders R.; Holmes, Mark A.; Parkhill, Julian; Peacock, Sharon J.
The emergence of mecC methicillin-resistant Staphylococcus aureus (MRSA) poses a diagnostic challenge for clinical microbiology laboratories. Using the Vitek 2 system, we tested a panel of 896 Staphylococcus aureus isolates and found that an oxacillin-sensitive/cefoxitin-resistant profile had a sensitivity of 88.7% and a specificity of 99.5% for the identification of mecC MRSA isolates. The presence of the mecC gene, determined by bacterial whole-genome sequencing, was used as the gold standard. This profile could provide a zero-cost screening method for identification of mecC-positive MRSA strains. PMID:23720794
Dar Mohammad J
Full Text Available Abstract Background The study was conducted between 2000 and 2003 on 750 human subjects, yielding 850 strains of staphylococci from clinical specimens (575, nasal cultures of hospitalized patients (100 and eye & nasal sources of hospital workers (50 & 125 respectively in order to determine their epidemiology, acquisition and dissemination of resistance genes. Methods Organisms from clinical samples were isolated, cultured and identified as per the standard routine procedures. Susceptibility was measured by the agar diffusion method, as recommended by the Nat ional Committee for Clinical Laboratory Standards (NCCLS. The modified method of Birnboin and Takahashi was used for isolation of plasmids from staphylococci. Pulsed-field gel electrophoresis (PFGE typing of clinical and carrier Methicillin resistant Staphylococcus aureus (MRSA strains isolated during our study was performed as described previously. Results It was shown that 35.1% of Staphylococcus aureus and 22.5% of coagulase-negative staphylococcal isolates were resistant to methicillin. Highest percentage of MRSA (35.5% was found in pus specimens (n = 151. The multiple drug resistance of all MRSA (n = 180 and Methicillin resistant Coagulase-negative Staphylococcus aureus (MRCNS (n = 76 isolates was detected. In case of both methicillin-resistant as well as methicillin-sensitive Saphylococcal isolates zero resistance was found to vancomycin where as highest resistance was found to penicillin G followed by ampicillin. It was shown that the major reservoir of methicillin resistant staphylococci in hospitals are colonized/infected inpatients and colonized hospital workers, with carriers at risk for developing endogenous infection or transmitting infection to health care workers and patients. The results were confirmed by molecular typing using PFGE by SmaI-digestion. It was shown that the resistant markers G and T got transferred from clinical S. aureus (JS-105 to carrier S. aureus (JN-49
Full Text Available The objective of this study was to find the prevalence of Staphylococcus spp. carriage among hospital personnel and hospital environment and their antibiogram with special emphasis on methicillin resistance. A total of 205 samples from hospital personnel and environment were collected from casualty, oncology and multidisciplinary cardiac unit ward of Kasturba Medical College Hospital, Manipal. Samples were collected using sterile cotton wool swabs and inoculated into brain heart infusion broth. Subcultures were done onto blood agar and MacConkey′s agar. Isolates were identified by standard methods up to species level. Antimicrobial susceptibility test was performed according to standardized disc diffusion Kirby-Bauer method. Each of the isolates was screened for methicillin resistance using oxacillin disc on Mueller Hinton agar plate followed by MIC for methicillin and cefoxitin susceptibility test by disc diffusion method. Sixty five out of 205 strains (31.7% were Staphylococcus spp. and all of them were coagulase negative. Most of the strains belonged to S.epidermidis 49.23%(32/65 followed by S. saprophyticus 26.15%(17/65. Maximum isolates of S.epidermidis were from anterior nares 28.12%(9/32 strains of S.epidermidis . Highest number of methicillin resistant coagulase negative strains (3/9, 33.33% were isolated from stethoscope of multidisciplinary cardiac unit ward followed by carriers in the anterior nares (2/9, 22.22%. Methicillin resistant coagulase negative staphylococci are prevalent in anterior nares of hospital personnel and in the hospital environment thereby providing a definite source for hospital acquired infection. All isolates were sensitive to vancomycin, ciprofloxacin and amikacin.
Short communication: Prevalence of methicillin resistance in coagulase-negative staphylococci and Staphylococcus aureus isolated from bulk milk on organic and conventional dairy farms in the United States.
Cicconi-Hogan, K M; Belomestnykh, N; Gamroth, M; Ruegg, P L; Tikofsky, L; Schukken, Y H
The objective of this study was to evaluate the presence of methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus spp. in bulk tank milk samples from 288 organic and conventional dairy farms located in New York, Wisconsin, and Oregon from March 2009 to May 2011. Due to recent publications reporting the presence mecC (a mecA homolog not detected by traditional mecA-based PCR methods), a combination of genotypic and phenotypic approaches was used to enhance the recovery of methicillin-resistant organisms from bulk tank milk. In total, 13 isolates were identified as methicillin resistant: Staph. aureus (n=1), Staphylococcus sciuri (n=5), Staphylococcus chromogenes (n=2), Staphylococcus saprophyticus (n=3), Staphylococcus agnetis (n=1), and Macrococcus caseolyticus (n=1). The single methicillin-resistant Staph. aureus isolate was identified from an organic farm in New York, for an observed 0.3% prevalence at the farm level. The methicillin-resistant coagulase-negative staphylococci prevalence was 2% in the organic population and 5% in the conventional population. We did not identify mecC in any of the isolates from our population. Of interest was the relatively high number of methicillin-resistant Staph. sciuri recovered, as the number of isolates from our study was considerably higher than those recovered from other recent studies that also assessed milk samples. Our research suggests that the presence of a potential methicillin-resistant Staphylococcus reservoir in milk, and likely the dairy farm population in the United States, is independent of the organic or conventional production system.
Scerri, Jeanesse; Monecke, Stefan; Borg, Michael A
Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen worldwide. Malta is one of the countries with the highest MRSA prevalence in Europe, as identified from hospital blood cultures . However, community prevalence of MRSA has never previously been investigated. This study aimed at establishing the prevalence of community MRSA nasal colonization in Maltese individuals and identifying the clonal characteristics of the detected isolates. Nasal swabs were collected from 329 healthy individuals who were also asked to complete a brief questionnaire about risk factors commonly associated with MRSA carriage and infection. The swabs were transported and enriched in a nutrient broth supplemented with NaCl. The presence of MRSA was then determined by culturing on MRSA Select chromogenic agar and then confirming by several assays, including catalase, coagulase and PBP2a agglutination tests. The isolates were assayed for antibiotic susceptibilities and typed by microarray analysis to determine the clonal characteristics of each strain. The prevalence of MRSA nasal colonization in the healthy Maltese population was found to be 8.81% (95% confidence interval [CI], 5.75-11.87%), much higher than that found in other studies carried out in several countries. No statistical association was found between MRSA carriage and demographics or risk factors; however, this was hindered by the small sample size. Almost all the isolates were fusidic-acid resistant. The majority were found to belong to a local endemic clone (CC5) which seems to be replacing the previously prevalent European clone UK-EMRSA-15 in the country. A new clone (CC50-MRSA-V) was also characterized. The presence of such a significant community reservoir of MRSA increases the burdens already faced by the local healthcare system to control the MRSA epidemic. Colonization of MRSA in otherwise healthy individuals may represent a risk for endogenous infection and transmission to hospitalized
Background Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is a well defined risk factor for subsequent bacteremia and death in various groups of patients, but its impact on outcome in patients receiving long-term hemodialysis (HD) is under debate. Methods This prospective interventional cohort study (performed 2004 to 2010) enrolled 289 HD outpatients of an urban dialysis-unit. Nasal swab cultures for MRSA were performed in all patients upon first admission, at transfer from another dialysis facility or readmission after hospitalisation. Nasal MRSA carriers were treated in a separate ward and received mupirocin nasal ointment. Concomitant extra-nasal MRSA colonization was treated with 0.2% chlorhexidine mouth rinse (throat) or octenidine dihydrochloride containing antiseptic soaps and 2% chlorhexidine body washes (skin). Clinical data and outcome of carriers and noncarriers were systematically analyzed. Results The screening approach identified 34 nasal MRSA carriers (11.7%). Extra-nasal MRSA colonization was observed in 11/34 (32%) nasal MRSA carriers. History of malignancy and an increased Charlson Comorbidity Index were significant predictors for nasal MRSA carriers, whereas traditional risk factors for MRSA colonization or markers of inflammation or malnutrition were not able to discriminate. Kaplan-Meier analysis demonstrated significant survival differences between MRSA carriers and noncarriers. Mupirocin ointment persistently eliminated nasal MRSA colonization in 26/34 (73.5%) patients. Persistent nasal MRSA carriers with failure of this eradication approach had an extremely poor prognosis with an all-cause mortality rate >85%. Conclusions Nasal MRSA carriage with failure of mupirocin decolonization was associated with increased mortality despite a lack of overt clinical signs of infection. Further studies are needed to demonstrate whether nasal MRSA colonization represents a novel predictor of worse outcome or just another
Bardiau, Marjorie; Yamazaki, Kazuko; Ote, Isabelle; Misawa, Naoaki; Mainil, Jacques G
The aim of this study was to explore the presence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in a collection of S. pseudintermedius strains isolated from dogs and cats with dermatitis in Japan and to compare their genotypic and phenotypic characteristics. Clonal relationships were determined by pulse field gel electrophoresis (PFGE), staphylococcal chromosomal cassette mec (SCCmec) typing, and multilocus sequence typing (MLST). Biofilm formation assay was performed using safranin staining in microplates. Three virulence genes coding for S. intermedius exfoliative toxin and Panton-Valentine leukocidin (siet, lukS-PV and lukF-PV) were searched for in a collection of strains. Antimicrobial resistance against 15 antibiotics was studied by a disc diffusion method. Twenty-seven MRSP were isolated. According to PFGE results the isolates were not closely related except for a few strains. MLST showed that the strains belonged to five groups, ST71 and ST26 being the two most prevalent. Three types of SCCmec (II, II-III and V) were identified. All isolates were siet-positive but PVL-negative. Most strains (except for two) produced strong biofilm in tryptic soy broth with glucose. Seventy-eight percent of the isolates were resistant or intermediate to twelve or more antibiotics. Our study demonstrates that the ST71 lineage is widespread in Japan and that ST26 could represent an emerging lineage. Moreover, most of our strains are capable of forming strong biofilm and possess siet gene, two virulence characteristics that probably help the bacteria to persist and spread. Finally, our MRSP strains show a strong resistance profile to antibiotics commonly used in veterinary medicine.
Latronico, Francesca; Moodley, Arshnee; Nielsen, Søren Saxmose; Guardabassi, Luca
The recent worldwide spread of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in dogs is a reason for concern due to the typical multidrug resistance patterns displayed by some MRSP lineages such as sequence type (ST) 71. The objective of this study was to compare the in vitro adherence properties between MRSP and methicillin-susceptible (MSSP) strains. Four MRSP, including a human and a canine strain belonging to ST71 and two canine non-ST71 strains, and three genetically unrelated MSSP were tested on corneocytes collected from five dogs and six humans. All strains were fully characterized with respect to genetic background and cell wall-anchored protein (CWAP) gene content. Seventy-seven strain-corneocyte combinations were tested using both exponential- and stationary-phase cultures. Negative binomial regression analysis of counts of bacterial cells adhering to corneocytes revealed that adherence was significantly influenced by host and strain genotype regardless of bacterial growth phase. The two MRSP ST71 strains showed greater adherence than MRSP non-ST71 (p pseudintermedius adherence to canine corneocytes was significantly higher compared to human corneocytes (p < 0.0001), but the MRSP ST71 strain of human origin adhered equally well to canine and human corneocytes, suggesting that MRSP ST71 may be able to adapt to human skin. The genetic basis of the enhanced in vitro adherence of ST71 needs to be elucidated as this phenotypic trait may be associated to the epidemiological success and zoonotic potential of this epidemic MRSP clone.
Oliveira, C J B; Tiao, N; de Sousa, F G C; de Moura, J F P; Santos Filho, L; Gebreyes, W A
The aim of this study was to investigate the phenotypic and genotypic diversity and anti-microbial resistance among staphylococci of dairy herds that originated from Paraiba State, north-eastern Brazil, a region where such studies are rare. Milk samples (n = 552) were collected from 15 dairy farms. Isolates were evaluated for anti-microbial susceptibility by Kirby-Bauer disc diffusion method. Confirmation of methicillin-resistant Staphylococcus aureus (MRSA) was performed using multiplex PCR targeting mecA and nuc genes in addition to phenotypic assay based on PBP-2a latex agglutination. Clonal relatedness of isolates was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) genotyping. Staphylococci were detected in 269 (49%) of the samples. Among these, 65 (24%) were S. aureus. The remaining 204 isolates were either coagulase-negative staphylococci (n = 188; 70%) or coagulase positive other than S. aureus (n = 16; 6%). Staphylococci were cultured in seven (35%) of the 20 hand swab samples, from which five isolates were S. aureus. The isolates were most commonly resistant against penicillin (43%), ampicillin (38%) and oxacillin (27%). The gene mecA was detected in 21 S. aureus from milk and in one isolate from a milker's hand. None of the isolates were resistant to vancomycin. PFGE findings showed high clonal diversity among the isolates. Based on MLST, we identified a total of 11 different sequence types (STs 1, 5, 6, 83, 97, 126, 1583, 1622, 1623, 1624 and 1625) with four novel STs (ST1622-ST1625). The findings show that MRSA is prevalent in milk from semi-extensive dairy cows in north-eastern Brazil, and further investigation on its extent in various types of milk production systems and the farm-to-table continuum is warranted.
Full Text Available The information of molecular characteristics and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus (MRSA is essential for control and treatment of diseases caused by this medically important pathogen. A total of 577 clinical MRSA bloodstream isolates from six major hospitals in Taiwan were determined for molecular types, carriage of Panton-Valentine leukocidin (PVL and sasX genes and susceptibilities to 9 non-beta-lactam antimicrobial agents. A total of 17 genotypes were identified in 577 strains by pulsotyping. Five major pulsotypes, which included type A (26.2%, belonging to sequence type (ST 239, carrying type III staphylococcal chromosomal cassette mec (SCCmec, type F (18.9%, ST5-SCCmecII, type C (18.5%, ST59-SCCmecIV, type B (12.0%, ST239-SCCmecIII and type D (10.9%, ST59-SCCmecVT/IV, prevailed in each of the six sampled hospitals. PVL and sasX genes were respectively carried by ST59-type D strains and ST239 strains with high frequencies (93.7% and 99.1%, respectively but rarely detected in strains of other genotypes. Isolates of different genotypes and from different hospitals exhibited distinct antibiograms. Multi-resistance to ≥3 non-beta-lactams was more common in ST239 isolates (100% than in ST5 isolates (97.2%, P = 0.0347 and ST59 isolates (8.2%, P<0.0001. Multivariate analysis further indicated that the genotype, but not the hospital, was an independent factor associated with muti-resistance of the MRSA strains. In conclusion, five common MRSA clones with distinct antibiograms prevailed in the major hospitals in Taiwan in 2010. The antimicrobial susceptibility pattern of invasive MRSA was mainly determined by the clonal distribution.
Full Text Available This study investigated the spread of MRSA (methicillin-resistant Staphylococcus aureus on two Belgian pig farms. Pigs of different ages (from farrowing to slaughter age and sows as well as the barn environment were screened extensively on two occasions three months apart. A subset of MRSA isolates was tested for antimicrobial susceptibility to 16 antibiotics and was further characterized by pulsed-field gel electrophoresis. Ninety-five percent and 77% of the tested pigs on farm A and farm B, respectively, were colonized with MRSA. MRSA positive animals were detected in all age categories sampled on each sampling day. Piglets were already colonized in the farrowing unit with the same or other MRSA strains than their mother. The prevalence of MRSA colonized pigs increased significantly after weaning and decreased during the fattening period. Pigs carried MRSA mainly in the nares, followed by the perineum and skin and to a lesser degree the rectum. A pig could be contaminated or colonized with different MRSA strains at the same time. The barn environment was also found to be contaminated with different MRSA strains, including the air inlet and outlet. All isolates tested on both farms were resistant to both tetracycline and trimethoprim, while they were susceptible to rifampicin, mupirocin and linezolid. There was a significant difference in resistance prevalence between the two farms for the antibiotics gentamicin, kanamycin, tobramycin, tylosin, lincomycin and quinupristin/dalfopristin. Furthermore, several antibiotic resistance profiles were observed within one farm. This study clearly indicates that several MRSA strains circulate on one farm, from the nursery unit to the fattening unit. This is important to consider when attempts are made to remediate these farms.
Hand hygiene is a key component in reducing infection. There are few reports on the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) on healthcare workers\\' (HCWs\\') hands. The aim of this study was to establish whether HCWs\\' fingertips were contaminated with MRSA in a clinical hospital setting. The study was conducted in an acute tertiary referral hospital on four MRSA wards that were part of a larger research study on MRSA epidemiology and four other wards not included in the study. The fingertips from all categories of 523 HCWs were sampled on 822 occasions by the imprinting of fingertips on MRSA chromogenic agar plates. The type of hand hygiene agent used, if any, and the immediate prior activity of the HCW were recorded. Overall, 38\\/822 (5%) fingertips from 523 HCWs were MRSA-positive; 12\\/194 (6%) after clinical contact, 10\\/138 (10%) after contact with the patient\\'s environment and 15\\/346 (4%) after no specific contact. MRSA was recovered on 2\\/61 (3%) occasions after use of alcohol hand rub, 2\\/35 (6%) after 4% chlorhexidine detergent, 7\\/210 (3%) hand washing with soap and water, and 27\\/493 (5%) when no hand hygiene had been performed. MRSA was recovered from HCWs on seven of the eight wards. MRSA was more frequently present on fingertips on the four non-study wards vs the four MRSA study wards [18\\/250 (7%), 3\\/201 (1%), respectively; P
Geva, Alon; Wright, Sharon B.; Baldini, Linda M.; Smallcomb, Jane A.; Safran, Charles
OBJECTIVE: Methicillin-resistant Staphylococcus aureus (MRSA) colonization in NICUs increases the risk of nosocomial infection. Network analysis provides tools to examine the interactions among patients and staff members that put patients at risk of colonization. METHODS: Data from MRSA surveillance cultures were combined with patient room locations, nursing assignments, and sibship information to create patient- and unit-based networks. Multivariate models were constructed to quantify the risk of incident MRSA colonization as a function of exposure to MRSA-colonized infants in these networks. RESULTS: A MRSA-negative infant in the NICU simultaneously with a MRSA-positive infant had higher odds of becoming colonized when the colonized infant was a sibling, compared with an unrelated patient (odds ratio: 8.8 [95% confidence interval [CI]: 5.3–14.8]). Although knowing that a patient was MRSA-positive and was placed on contact precautions reduced the overall odds of another patient becoming colonized by 35% (95% CI: 20%–47%), having a nurse in common with that patient still increased the odds of colonization by 43% (95% CI: 14%–80%). Normalized group degree centrality, a unitwide network measure of connectedness between colonized and uncolonized patients, was a significant predictor of incident MRSA cases (odds ratio: 18.1 [95% CI: 3.6–90.0]). CONCLUSIONS: Despite current infection-control strategies, patients remain at significant risk of MRSA colonization from MRSA-positive siblings and from other patients with whom they share nursing care. Strategies that minimize the frequency of staff members caring for both colonized and uncolonized infants may be beneficial in reducing the spread of MRSA colonization. PMID:22007011
Binh An Diep
Full Text Available Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA strains typically carry genes encoding Panton-Valentine leukocidin (PVL. We used wild-type parental and isogenic PVL-deletion (Delta pvl strains of USA300 (LAC and SF8300 and USA400 (MW2 to test whether PVL alters global gene regulatory networks and contributes to pathogenesis of bacteremia, a hallmark feature of invasive staphylococcal disease. Microarray and proteomic analyses revealed that PVL does not alter gene or protein expression, thereby demonstrating that any contribution of PVL to CA-MRSA pathogenesis is not mediated through interference of global gene regulatory networks. Inasmuch as a direct role for PVL in CA-MRSA pathogenesis remains to be determined, we developed a rabbit bacteremia model of CA-MRSA infection to evaluate the effects of PVL. Following experimental infection of rabbits, an animal species whose granulocytes are more sensitive to the effects of PVL compared with the mouse, we found a contribution of PVL to pathogenesis over the time course of bacteremia. At 24 and 48 hours post infection, PVL appears to play a modest, but measurable role in pathogenesis during the early stages of bacteremic seeding of the kidney, the target organ from which bacteria were not cleared. However, the early survival advantage of this USA300 strain conferred by PVL was lost by 72 hours post infection. These data are consistent with the clinical presentation of rapid-onset, fulminant infection that has been associated with PVL-positive CA-MRSA strains. Taken together, our data indicate a modest and transient positive effect of PVL in the acute phase of bacteremia, thereby providing evidence that PVL contributes to CA-MRSA pathogenesis.
Hatcher, S M; Myers, K W; Heaney, C D; Larsen, J; Hall, D; Miller, M B; Stewart, J R
Industrial hog operations (IHOs) have been identified as a source of antibiotic-resistant Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). However, few studies have investigated the presence of antibiotic-resistant S. aureus in the environment near IHOs, specifically surface waters proximal to spray fields where IHO liquid lagoon waste is sprayed. Surface water samples (n=179) were collected over the course of approximately one year from nine locations in southeastern North Carolina and analyzed for the presence of presumptive MRSA using CHROMagar MRSA media. Culture-based, biochemical, and molecular tests, as well as matrix-assisted laser desorption/ionization-time of flight mass spectrometry were used to confirm that isolates that grew on CHROMagar MRSA media were S. aureus. Confirmed S. aureus isolates were then tested for susceptibility to 16 antibiotics and screened for molecular markers of MRSA (mecA, mecC) and livestock adaptation (absence of scn). A total of 12 confirmed MRSA were detected in 9 distinct water samples. Nine of 12 MRSA isolates were also multidrug-resistant (MDRSA [i.e., resistant to ≥3 antibiotic classes]). All MRSA were scn-positive and most (11/12) belonged to a staphylococcal protein A (spa) type t008, which is commonly associated with humans. Additionally, 12 confirmed S. aureus that were methicillin-susceptible (MSSA) were recovered, 7 of which belonged to spa type t021 and were scn-negative (a marker of livestock-adaptation). This study demonstrated the presence of MSSA, MRSA, and MDRSA in surface waters adjacent to IHO lagoon waste spray fields in southeastern North Carolina. To our knowledge, this is the first report of waterborne S. aureus from surface waters proximal to IHOs.
Wang, Xiaoguang; Ouyang, Lin; Luo, Lingfei; Liu, Jiqian; Song, Chiping; Li, Cuizhen; Yan, Hongjing; Wang, Ping
Methicillin-resistant Staphylococcus aureus (MRSA) strains are now common both in the health care setting and in the community. Active surveillance is critical for MRSA control and prevention. Specimens of patients (200 patients with 1119 specimens) as well as medical staff and hospital setting (1000 specimens) were randomly sampled in a level 2 hospital in Shanghai from September 2011 to August 2012. Isolation, cultivation and identification of S. aureus were performed. Totally, 67 S. aureus strains were isolated. 32 S. aureus strains were isolated from patient samples; 13 (13/32, 40.6%) of the 32 S. aureus isolates were MRSA; sputum sample and patients in the department of general internal medicine were the most frequent specimen and patient group for S. aureus strains isolation. Remaining 35 S. aureus strains were isolated from the medical staff and hospital setting; 20 (20/35, 57.1%) of the 35 S. aureus isolates were MRSA; specimens sampled from doctors and nurses' hands and nose and hospital facilities were the most frequent samples to isolate S. aureus. Resistant and virulent genes detection showed that, all 33 MRSA strains were mecA positive which accounts for 49.3% of the 67 S. aureus strains; 38 isolates were Panton-Valentine leukocidin (PVL) gene positive which accounts for 56.7% of the 67 S. aureus strains; and 17 (17/67, 25.4%) isolates are mecA and PVL genes dual positive. Multidrug-resistant strains of MRSA and PVL positive S. aureus are common in patients, medical staff and hospital setting, the potential health threat is worthy of our attention.
Rudkin, Justine K; Laabei, Maisem; Edwards, Andrew M; Joo, Hwang-Soo; Otto, Michael; Lennon, Katrina L; O'Gara, James P; Waterfield, Nicholas R; Massey, Ruth C
The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a growing cause for concern. These strains are more virulent than health care-associated MRSA (HA-MRSA) due to higher levels of toxin expression. In a previous study, we showed that the high-level expression of PBP2a, the alternative penicillin binding protein encoded by the mecA gene on type II staphylococcal cassette chromosome mec (SCCmec) elements, reduced toxicity by interfering with the Agr quorum sensing system. This was not seen in strains carrying the CA-MRSA-associated type IV SCCmec element. These strains express significantly lower levels of PBP2a than the other MRSA type, which may explain their relatively high toxicity. We hypothesized that as oxacillin is known to increase mecA expression levels, it may be possible to attenuate the toxicity of CA-MRSA by using this antibiotic. Subinhibitory oxacillin concentrations induced PBP2a expression, repressed Agr activity, and, as a consequence, decreased phenol-soluble modulin (PSM) secretion by CA-MRSA strains. However, consistent with other studies, oxacillin also increased the expression levels of alpha-toxin and Panton-Valentine leucocidin (PVL). The net effect of these changes on the ability to lyse diverse cell types was tested, and we found that where the PSMs and alpha-toxin are important, oxacillin reduced overall lytic activity, but where PVL is important, it increased lytic activity, demonstrating the pleiotropic effect of oxacillin on toxin expression by CA-MRSA.
Hoet, Armando E; Johnson, Amanda; Nava-Hoet, Rocio C; Bateman, Shane; Hillier, Andrew; Dyce, John; Gebreyes, Wondwossen A; Wittum, Thomas E
Concurrent to reports of zoonotic and nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) in veterinary settings, recent evidence indicates that the environment in veterinary hospitals may be a potential source of MRSA. The present report is a cross-sectional study to determine the prevalence of MRSA on specific human and animal contact surfaces at a large veterinary hospital during a nonoutbreak period. A total of 156 samples were collected using Swiffers(®) or premoistened swabs from the small animal, equine, and food animal sections. MRSA was isolated and identified by pre-enrichment culture and standard microbiology procedures, including growth on Mueller-Hinton agar supplemented with NaCl and oxacillin, and by detection of the mecA gene. Staphylococcal chromosome cassette mec (SCCmec) typing and pulsed-field gel electrophoresis profile were also determined. MRSA was detected in 12% (19/157) of the hospital environments sampled. The prevalence of MRSA in the small animal, equine, and food animal areas were 16%, 4%, and 0%, respectively. Sixteen of the MRSA isolates from the small animal section were classified as USA100, SCCmec type II, two of which had pulsed-field gel electrophoresis pattern that does not conform to any known type. The one isolate obtained from the equine section was classified as USA500, SCCmec type IV. The molecular epidemiological analysis revealed a very diverse population of MRSA isolates circulating in the hospital; however, in some instances, multiple locations/surfaces, not directly associated, had the same MRSA clone. No significant difference was observed between animal and human contact surfaces in regard to prevalence and type of isolates. Surfaces touched by multiple people (doors) and patients (carts) were frequently contaminated with MRSA. The results from this study indicate that MRSA is present in the environment even during nonoutbreak periods. This study also identified specific surfaces in a
Nakaminami, Hidemasa; Ito, Teruyo; Han, Xiao; Ito, Ayumu; Matsuo, Miki; Uehara, Yuki; Baba, Tadashi; Hiramatsu, Keiichi; Noguchi, Norihisa
SasX is a known virulence factor of Staphylococcus aureus involved in colonisation and immune evasion of the bacterium. The sasX gene, which is located on the ϕSPβ prophage, is frequently found in the sequence type (ST) 239 S. aureus lineage, which is the predominant healthcare-associated clone in Asian countries. In Japan, ST239 clones have rarely been identified, and sasX-positive strains have not been reported to date. Here, we report the first identification of 18 sasX-positive methicillin-resistant S. aureus (MRSA) strains in Japanese hospitals between 2009 and 2011. All sasX-positive isolates belonged to an ST239-staphylococcal cassette chromosome mec type III (ST239-III) lineage. However, we were unable to identify additional sasX-positive MRSA strains from 2012 to 2016, indicating that the small epidemic of sasX-positive isolates observed in this study was temporary. The sequence surrounding sasX in the strain TOHH628 lacked 51 genes that encode phage packaging and structural proteins, and no bacteriophage was induced by mitomycin C. Additionally, in the TOHH628 strain, the region (64.6 kb) containing sasX showed high identity to the ϕSPβ-like element (71.3 kb) of the Taiwanese MRSA strain Z172. The data strongly suggest that the present sasX-positive isolates found in Japanese hospitals were transmitted incidentally from other countries. © FEMS 2017. All rights reserved. For permissions, please e-mail: email@example.com.
Kannappan, Arunachalam; Gowrishankar, Shanmugaraj; Srinivasan, Ramanathan; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera
Methicillin-resistant Staphylococcus aureus (MRSA) is a leading human pathogen responsible for causing chronic clinical manifestation worldwide. In addition to antibiotic resistance genes viz. mecA and vanA, biofilm formation plays a prominent role in the pathogenicity of S. aureus by enhancing its resistance to existing antibiotics. Considering the role of folk medicinal plants in the betterment of human health from the waves of multidrug resistant bacterial infections, the present study was intended to explore the effect of Vetiveria zizanioides root on the biofilm formation of MRSA and its clinical counterparts. V. zizanioides root extract (VREX) showed a concentration-dependent reduction in biofilm formation without hampering the cellular viability of the tested strains. Micrographs of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) portrayed the devastating impact of VREX on biofilm formation. In addition to antibiofilm activity, VREX suppresses the production of biofilm related phenotypes such as exopolysaccharide, slime and α-hemolysin toxin. Furthermore, variation in FT-IR spectra evidenced the difference in cellular factors of untreated and VREX treated samples. Result of mature biofilm disruption assay and down regulation of genes like fnbA, fnbB, clfA suggested that VREX targets these adhesin genes responsible for initial adherence. GC-MS analysis revealed the presence of sesquiterpenes as a major constituent in VREX. Thus, the data of present study strengthen the ethnobotanical value of V. zizanioides and concludes that VREX contain bioactive molecules that have beneficial effect over the biofilm formation of MRSA and its clinical isolates. Copyright © 2017 Elsevier Ltd. All rights reserved.
Sang Mi Han
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA, along with other antibiotic resistant bacteria, has become a significant social and clinical problem. There is thus an urgent need to develop naturally bioactive compounds as alternatives to the few antibiotics that remain effective. Here we assessed the in vitro activities of bee venom (BV, alone or in combination with ampicillin, penicillin, gentamicin or vancomycin, on growth of MRSA strains. The antimicrobial activity of BV against MRSA strains was investigated using minimum inhibitory concentrations (MIC, minimum bactericidal concentrations (MBC and a time-kill assay. Expression of atl which encodes murein hydrolase, a peptidoglycan-degrading enzyme involved in cell separation, was measured by reverse transcription-polymerase chain reaction. The MICs of BV were 0.085 µg/mL and 0.11 µg/mL against MRSA CCARM 3366 and MRSA CCARM 3708, respectively. The MBC of BV against MRSA 3366 was 0.106 µg/mL and that against MRSA 3708 was 0.14 µg/mL. The bactericidal activity of BV corresponded to a decrease of at least 3 log CFU/g cells. The combination of BV with ampicillin or penicillin yielded an inhibitory concentration index ranging from 0.631 to 1.002, indicating a partial and indifferent synergistic effect. Compared to ampicillin or penicillin, both MRSA strains were more susceptible to the combination of BV with gentamicin or vancomycin. The expression of atl gene was increased in MRSA 3366 treated with BV. These results suggest that BV exhibited antibacterial activity and antibiotic-enhancing effects against MRSA strains. The atl gene was increased in MRSA exposed to BV, suggesting that cell division was interrupted. BV warrants further investigation as a natural antimicrobial agent and synergist of antibiotic activity.
Megan R Kiedrowski
Full Text Available Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA is an emerging contributor to biofilm-related infections. We recently reported that strains lacking sigma factor B (sigB in the USA300 lineage of CA-MRSA are unable to develop a biofilm. Interestingly, when spent media from a USA300 sigB mutant was incubated with other S. aureus strains, biofilm formation was inhibited. Following fractionation and mass spectrometry analysis, the major anti-biofilm factor identified in the spent media was secreted thermonuclease (Nuc. Considering reports that extracellular DNA (eDNA is an important component of the biofilm matrix, we investigated the regulation and role of Nuc in USA300. The expression of the nuc gene was increased in a sigB mutant, repressed by glucose supplementation, and was unaffected by the agr quorum-sensing system. A FRET assay for Nuc activity was developed and confirmed the regulatory results. A USA300 nuc mutant was constructed and displayed an enhanced biofilm-forming capacity, and the nuc mutant also accumulated more high molecular weight eDNA than the WT and regulatory mutant strains. Inactivation of nuc in the USA300 sigB mutant background partially repaired the sigB biofilm-negative phenotype, suggesting that nuc expression contributes to the inability of the mutant to form biofilm. To test the generality of the nuc mutant biofilm phenotypes, the mutation was introduced into other S. aureus genetic backgrounds and similar increases in biofilm formation were observed. Finally, using multiple S. aureus strains and regulatory mutants, an inverse correlation between Nuc activity and biofilm formation was demonstrated. Altogether, our findings confirm the important role for eDNA in the S. aureus biofilm matrix and indicates Nuc is a regulator of biofilm formation.
Loncaric, Igor; Künzel, Frank; Licka, Theresia; Simhofer, Hubert; Spergser, Joachim; Rosengarten, Renate
The aim of this study was to investigate the antimicrobial resistance, resistance gene patterns and genetic relatedness of a collection of Austrian methicillin-resistant Staphylococcus aureus (MRSA) isolates from companion animals and horses. A total of 89 non-repetitive MRSA isolates collected during routine veterinary microbiological examinations from April 2004 to the end of 2012, and one isolate from 2013 were used for this study. The presence of mecA and other resistance genes was confirmed by PCR. Isolates were genotyped by spa typing, two multiple-locus variable-number tandem repeat analyses (MLVA) analyses, SCCmec typing and multilocus sequence typing (MLST). PCR targeting Panton-Valentine leukocidin (PVL) and detection of staphylococcal enterotoxins (SE), toxic shock syndrome toxin (TSST) was performed using PCR assays. Antimicrobial susceptibility testing was performed. Five sequence types (STs-ST398, ST254, ST22, ST5 and ST1), SCCmec types II, IVa, V, and non-type-abele, 8 spa-types (t003, t011, t036, t127, t386, t1348, and t4450), and two isolates could not be assigned, 21 MLVA-14Orsay types Multiplex-PCR MLVA (mMLVA) displayed 17 different MLVA types. The present study is the most comprehensive dealing with MRSA from Austrian companion animals and horses. The results confirm that MRSA ST398 is present in a wide range of animal species and is predominant especially in horses. In other companion animals it is unclear whether the infections with the different MRSA isolates investigated in the present study truly represents a rare phenomenon or may be an emerging problem in companion animals.
Sopena-Galindo, Nieves; Hornero-Lopez, Anna; Freixas-Sala, Núria; Bella-Cueto, Feliu; Pérez-Jové, Josefa; Limon-Cáceres, Enric; Gudiol-Munté, Francesc
VINCat is a nosocomial infection surveillance program in hospitals in Catalonia. The aim of the study was to determine the surveillance and control measures of methicillin-resistant Staphylococcus aureus (MRSA) in these centres. An e-mail survey was carried out from January to March 2013 with questions related to the characteristics of the hospitals and their control measures for MRSA. A response was received from 53 hospitals (>500 beds: 7; 200-500 beds: 14;<200 beds: 32; had ICU: 29). Computer alert of readmissions was available in 63%. There was active surveillance of patients admitted from another hospital (46.2%) or a long-term-care centre (55.8%), both being significantly more common measures in hospitals with a rate of MRSA≤22% (global median). Compliance with hand hygiene was observed in 77.4% of the centres, and was greater than 50% in 69.7% of them. All hospitals had contact precautions, although 62.3% did not have exclusive frequently used clinical material in bedrooms. The room cleaning was performed more frequently in 54.7% of hospitals, and 67.9% of them had programs for the appropriate use of antibiotics. This study provides information on the implementation of measures to prevent MRSA in hospitals participating in the VINCat program. Most of the centres have an MRSA protocol, however compliance with it should be improved, especially in areas such as active detection on admission in patients at risk, hand hygiene adherence, cleaning frequency and optimising the use of antibiotics. Copyright © 2015 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.
Althaqafi, Abdulhakeem O; Matar, Madonna J; Moghnieh, Rima; Alothman, Adel F; Alenazi, Thamer H; Farahat, Fayssal; Corman, Shelby; Solem, Caitlyn T; Raghubir, Nirvana; Macahilig, Cynthia; Haider, Seema; Stephens, Jennifer M
The objective of this study is to describe the real-world treatment patterns and burden of suspected or confirmed methicillin-resistant Staphylococcus aureus (MRSA) pneumonia in Saudi Arabia and Lebanon. A retrospective chart review study evaluated 2011-2012 data from hospitals in Saudi Arabia and Lebanon. Patients were included if they had been discharged with a diagnosis of MRSA pneumonia, which was culture proven or suspected based on clinical criteria. Hospital data were abstracted for a random sample of patients to capture demographics (eg, age and comorbidities), treatment patterns (eg, timing and use of antimicrobials), hospital resource utilization (eg, length of stay), and clinical outcomes (eg, clinical status at discharge and mortality). Descriptive results were reported using frequencies or proportions for categorical variables and mean and standard deviation for continuous variables. Chart-level data were collected for 93 patients with MRSA pneumonia, 50 in Saudi Arabia and 43 in Lebanon. The average age of the patients was 56 years, and 60% were male. The most common comorbidities were diabetes (39%), congestive heart failure (30%), coronary artery disease (29%), and chronic obstructive pulmonary disease (28%). Patients most frequently had positive cultures from pulmonary (87%) and blood (27%) samples. All isolates were sensitive to vancomycin, teicoplanin, and linezolid, and only one-third of the isolates tested were sensitive to ciprofloxacin. Beta-lactams (inactive therapy for MRSA) were prescribed 21% of the time across all lines of therapy, with 42% of patients receiving first-line beta-lactams. Fifteen percent of patients did not receive any antibiotics that were considered to be MRSA active. The mean hospital length of stay was 32 days, and in-hospital mortality was 30%. The treatment for MRSA pneumonia in Saudi Arabia and Lebanon may be suboptimal with inactive therapy prescribed a substantial proportion of the time. The information gathered
Kadlec, Kristina; Schwarz, Stefan; Goering, Richard V; Weese, J Scott
Methicillin-resistant Staphylococcus pseudintermedius (MRSP) has emerged in a remarkable manner as an important problem in dogs and cats. However, limited molecular epidemiological information is available. The aims of this study were to apply direct repeat unit (dru) typing in a large collection of well-characterized MRSP isolates and to use dru typing to analyze a collection of previously uncharacterized MRSP isolates. Two collections of MRSP isolates from dogs and cats were included in this study. The first collection comprised 115 well-characterized MRSP isolates from North America and Europe. The data for these isolates included multilocus sequence typing (MLST) and staphylococcal protein A gene (spa) typing results as well as SmaI macrorestriction patterns after pulsed-field gel electrophoresis (PFGE). The second collection was a convenience sample of 360 isolates from North America. The dru region was amplified by PCR, sequenced, and analyzed. For the first collection, the discriminatory indices of the typing methods were calculated. All isolates were successfully dru typed. The discriminatory power for dru typing (D = 0.423) was comparable to that of spa typing (D = 0.445) and of MLST (D = 0.417) in the first collection. Occasionally, dru typing was able to further discriminate between isolates that shared the same spa type. Among all 475 isolates, 26 different dru types were identified, with 2 predominant types (dt9a and dt11a) among 349 (73.4%) isolates. The results of this study underline that dru typing is a useful tool for MRSP typing, being an objective, standardized, sequence-based method that is relatively cost-efficient and easy to perform.
Kizerwetter-Świda, Magdalena; Chrobak-Chmiel, Dorota; Rzewuska, Magdalena; Binek, Marian
Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is being reported with an increasing frequency in small animal veterinary practice. The molecular typing of MRSP isolates revealed that the dominating European multidrug-resistant lineage is the sequence type 71 (ST71), associated with staphylococcal chromosomal cassette SCCmec type II-III. However, the recent reports indicated the emergence of other clones. The study aimed to determine the genetic properties of MRSP isolates obtained from dogs in Poland over a ten-year period. A total of 42 clinical MRSP isolates were subjected to multilocus-sequence typing (MLST) and SCCmec typing. MLST typing of 42 MRSP isolates yielded six STs belonging to two major clonal complexes (CCs): CC71 and CC551, associated with SCCmec element II-III and V, respectively. CC71 comprising ST71 and its newly described single locus variant (SLV) ST680. The second dominating CC551was represented by ST551 and newly described SLV ST771. The other, ST258 and ST85 were detected in single MRSP isolates. This is the first report concerning MLST typing of MRSP isolates in Poland. The results confirmed the domination of ST71 among MRSP until 2015, and the emergence of ST551 in 2015. Furthermore, in 2016 ST551 was identified in the majority of the strains, indicating the changes in the population structure of MRSP in Poland. Polish clinical MRSP isolates showed a shift in the population structure during the period of 2007 and 2016. The dominating MRSP lineage until 2015 was multidrug-resistant ST71-SCCmecII-III. The other lineage ST551-SCCmecV emerged in Poland since 2015, and in 2016 was found in the majority of MRSP isolates. Copyright © 2017 Elsevier B.V. All rights reserved.
Zoraghi, Roya; See, Raymond H; Axerio-Cilies, Peter; Kumar, Nag S; Gong, Huansheng; Moreau, Anne; Hsing, Michael; Kaur, Sukhbir; Swayze, Richard D; Worrall, Liam; Amandoron, Emily; Lian, Tian; Jackson, Linda; Jiang, Jihong; Thorson, Lisa; Labriere, Christophe; Foster, Leonard; Brunham, Robert C; McMaster, William R; Finlay, B Brett; Strynadka, Natalie C; Cherkasov, Artem; Young, Robert N; Reiner, Neil E
Novel classes of antimicrobials are needed to address the challenge of multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA). Using the architecture of the MRSA interactome, we identified pyruvate kinase (PK) as a potential novel drug target based upon it being a highly connected, essential hub in the MRSA interactome. Structural modeling, including X-ray crystallography, revealed discrete features of PK in MRSA, which appeared suitable for the selective targeting of the bacterial enzyme. In silico library screening combined with functional enzymatic assays identified an acyl hydrazone-based compound (IS-130) as a potent MRSA PK inhibitor (50% inhibitory concentration [IC50] of 0.1 μM) with >1,000-fold selectivity over human PK isoforms. Medicinal chemistry around the IS-130 scaffold identified analogs that more potently and selectively inhibited MRSA PK enzymatic activity and S. aureus growth in vitro (MIC of 1 to 5 μg/ml). These novel anti-PK compounds were found to possess antistaphylococcal activity, including both MRSA and multidrug-resistant S. aureus (MDRSA) strains. These compounds also exhibited exceptional antibacterial activities against other Gram-positive genera, including enterococci and streptococci. PK lead compounds were found to be noncompetitive inhibitors and were bactericidal. In addition, mutants with significant increases in MICs were not isolated after 25 bacterial passages in culture, indicating that resistance may be slow to emerge. These findings validate the principles of network science as a powerful approach to identify novel antibacterial drug targets. They also provide a proof of principle, based upon PK in MRSA, for a research platform aimed at discovering and optimizing selective inhibitors of novel bacterial targets where human orthologs exist, as leads for anti-infective drug development.
Baines, Sarah L.; Holt, Kathryn E.; Schultz, Mark B.; Seemann, Torsten; Howden, Brian O.; Jensen, Slade O.; van Hal, Sebastiaan J.; Coombs, Geoffrey W.; Firth, Neville; Powell, David R.; Stinear, Timothy P.
ABSTRACT Infections caused by highly successful clones of hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) are a major public health burden. The globally dominant sequence type 239 (ST239) HA-MRSA clone has persisted in the health care setting for decades, but the basis of its success has not been identified. Taking a collection of 123 ST239 isolates spanning 32 years, we have used population-based functional genomics to investigate the evolution of this highly persistent and successful clone. Phylogenetic reconstruction and population modeling uncovered a previously unrecognized distinct clade of ST239 that was introduced into Australia from Asia and has perpetuated the epidemic in this region. Functional analysis demonstrated attenuated virulence and enhanced resistance to last-line antimicrobials, the result of two different phenomena, adaptive evolution within the original Australian ST239 clade and the introduction of a new clade displaying shifts in both phenotypes. The genetic diversity between the clades allowed us to employ genome-wide association testing and identify mutations in other essential regulatory systems, including walKR, that significantly associate with and may explain these key phenotypes. The phenotypic convergence of two independently evolving ST239 clades highlights the very strong selective pressures acting on HA-MRSA, showing that hospital environments have favored the accumulation of mutations in essential MRSA genes that increase resistance to antimicrobials, attenuate virulence, and promote persistence in the health care environment. Combinations of comparative genomics and careful phenotypic measurements of longitudinal collections of clinical isolates are giving us the knowledge to intelligently address the impact of current and future antibiotic usage policies and practices on hospital pathogens globally. PMID:25736880
Wang, Xiaoguang; Ouyang, Lin; Luo, Lingfei; Liu, Jiqian; Song, Chiping; Li, Cuizhen; Yan, Hongjing; Wang, Ping
Methicillin-resistant Staphylococcus aureus (MRSA) strains are now common both in the health care setting and in the community. Active surveillance is critical for MRSA control and prevention. Specimens of patients (200 patients with 1119 specimens) as well as medical staff and hospital setting (1000 specimens) were randomly sampled in a level 2 hospital in Shanghai from September 2011 to August 2012. Isolation, cultivation and identification of S. aureus were performed. Totally, 67 S. aureus strains were isolated. 32 S. aureus strains were isolated from patient samples; 13 (13/32, 40.6%) of the 32 S. aureus isolates were MRSA; sputum sample and patients in the department of general internal medicine were the most frequent specimen and patient group for S. aureus strains isolation. Remaining 35 S. aureus strains were isolated from the medical staff and hospital setting; 20 (20/35, 57.1%) of the 35 S. aureus isolates were MRSA; specimens sampled from doctors and nurses’ hands and nose and hospital facilities were the most frequent samples to isolate S. aureus. Resistant and virulent genes detection showed that, all 33 MRSA strains were mecA positive which accounts for 49.3% of the 67 S. aureus strains; 38 isolates were Panton-Valentine leukocidin (PVL) gene positive which accounts for 56.7% of the 67 S. aureus strains; and 17 (17/67, 25.4%) isolates are mecA and PVL genes dual positive. Multidrug-resistant strains of MRSA and PVL positive S. aureus are common in patients, medical staff and hospital setting, the potential health threat is worthy of our attention. PMID:28030828
Full Text Available The spread of methicillin-resistant Staphylococcus aureus (MRSA is a critical health issue that has drawn greater attention to the potential use of immunotherapy. Toll-like receptor 2 (TLR2, a pattern recognition receptor, is an essential component in host innate defense system against S. aureus infection. However, little is known about the innate immune response, specifically TLR2 activation, against MRSA infection. Here, we evaluate the protective effect and the mechanism of MRSA murine pneumonia after pretreatment with Pam3CSK4, a TLR2 agonist. We found that the MRSA-pneumonia mouse model, pretreated with Pam3CSK4, had reduced bacteria and mortality in comparison to control mice. As well, lower protein and mRNA levels of TNF-α, IL-1β and IL-6 were observed in lungs and bronchus of the Pam3CSK4 pretreatment group. Conversely, expression of anti-inflammatory cytokine IL-10, but not TGF-β, increased in Pam3CSK4-pretreated mice. Our additional studies showed that CXCL-2 and CXCL1, which are necessary for neutrophil recruitment, were less evident in the Pam3CSK4-pretreated group compared to control group, whereas the expression of Fcγ receptors (FcγⅠ/Ⅲ and complement receptors (CR1/3 increased in murine lungs. Furthermore, we found that increased survival and improved bacterial clearance were not a result of higher levels of neutrophil infiltration, but rather a result of enhanced phagocytosis and bactericidal activity of neutrophils in vitro and in vivo as well as increased robust oxidative activity and release of lactoferrin. Our cumulative findings suggest that Pam3CSK4 could be a novel immunotherapeutic candidate against MRSA pneumonia.
Kaur, Sandeep; Harjai, Kusum; Chhibber, Sanjay
Phage therapy presents an alternative approach against the emerging methicillin-resistant Staphylococcus aureus (MRSA) threat. Some of the problems encountered during isolation of MRSA phages include the high prevalence of enteric phages in natural sources, nonspecific absorption of viable phage, and the formation of pinpoint or tiny plaques. The phage isolated in this study, MR-5, also formed tiny plaques against its host S. aureus ATCC 43300 (MRSA), making its detection and enumeration difficult. An improved method of increasing the plaque size of MRSA phage by incorporating sublethal concentrations of three different classes of antibiotics (inhibitors of protein synthesis) in the classical double-layer agar (DLA) method was investigated. The β-lactam and quinolone antibiotics commonly employed in earlier studies for increasing the plaque size did not show any significant effect on the plaque size of isolated MR-5 phage. Linezolid (oxazolidinone class), tetracycline, and ketolide antibiotics brought significant enhancements (3 times the original size) in the plaque size of MR-5 phage. Prior treatment with these antibiotics resulted in significant reductions in the time of adsorption and the latent period of MR-5 phage. To rule out whether the action of linezolid (which brought the maximum increase in plaque size) was specific for a single phage only, its effect on the plaque size of seven other S. aureus-specific phages was also assessed. Significant enhancements in the plaque size of these phages were observed. These results indicate that this modification can therefore safely be incorporated in the traditional DLA overlay method to search for new MRSA-virulent phages.
Ekambaram, Sanmuga Priya; Perumal, Senthamil Selvan; Balakrishnan, Ajay; Marappan, Nathiya; Gajendran, Sabari Srinivasan; Viswanathan, Vinodhini
Aim/Background: Medicinal plants have ability to resist microorganisms by synthesizing secondary metabolites such as phenols. Rosmarinic acid (RA) is a phenylpropanoid widely distributed in plants and well known as therapeutic and cosmetic agent. Methicillin-resistant Staphylococcus aureus (MRSA) which is resistant to all kinds of β-lactams, threatens even most potent antibiotics. To improve the efficiency of antibiotics against multi-drug resistant bacteria and to reduce the antibiotic dose, the antibacterial activity and the synergistic effect of RA with standard antibiotics against S. aureus and MRSA was investigated. Materials and Methods: Antibacterial activity of RA against S. aureus and a clinical isolate of MRSA was evaluated by agar well diffusion method. Minimum inhibitory concentration (MIC) of RA was determined by broth dilution method. Synergism of RA with various antibiotics against S. aureus and MRSA was studied by broth checkerboard method and time-kill kinetic assay. Effect of RA on microbial surface components recognizing adhesive matrix molecules (MSCRAMM’s) of S. aureus and MRSA was studied using sodium dodecyl sulfate - polyacrylamide gel electrophoresis. Results: MIC of RA was found to be 0.8 and 10 mg/ml against S. aureus and MRSA, respectively. RA was synergistic with vancomycin, ofloxacin, and amoxicillin against S. aureus and only with vancomycin against MRSA. The time-kill analysis revealed that synergistic combinations were a more effective than individual antibiotics. MSCRAMM’s protein expression of S. aureus and MRSA was markedly suppressed by RA + vancomycin combination rather than RA alone. Conclusion: The synergistic effects of RA with antibiotics were observed against S. aureus and MRSA. RA showed inhibitory effect on the surface proteins MSCRAMM’s. Even though RA was shown to exhibit a synergistic effect with antibiotics, the MIC was found to be higher. Thus, further studies on increasing the efficacy of RA can develop it
Chelsea G Himsworth
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA is an important cause of multi-drug-resistant infections in people, particularly indigent populations. MRSA can be transmitted between people and domestic animals, but the potential for transmission between people and commensal pests, particularly rodents, had not been investigated. The objective of this study was to identify the presence and characterize the ecology of MRSA in rats (Rattus spp. from in an impoverished, inner-city neighborhood. Oropharyngeal swabs were collected from rats trapped in 33 city blocks and one location within the adjacent port. Bacterial culture was performed and MRSA isolates were characterized using a variety of methods, including whole-genome sequencing (WGS. The ecology of MRSA in rats was described using phylogenetic analysis, geospatial analysis, and generalized linear mixed models. MRSA was identified 22 of 637 (3.5% rats tested, although prevalence varied from 0 - 50% among blocks. Isolates belonged to 4 clusters according to WGS, with the largest cluster (n = 10 containing isolates that were genetically indistinguishable from community-acquired USA300 MRSA strains isolated from people within the study area. MRSA strains demonstrated both geographic clustering and dispersion. The odds of an individual rat carrying MRSA increased with increased body fat (OR = 2.53, 95% CI = 1.33-4.82, and in the winter (OR = 5.29, 95% CI = 1.04-26.85 and spring (OR = 5.50, 95% CI = 1.10-27.58 compared to the fall. The results show that urban rats carried the same MRSA lineages occurring in local human and/or animal populations, supporting recent transmission from external sources. MRSA carriage was influenced by season, most likely as a result of temporal variation in rat behavior and rat-human interactions.
Rodríguez-Mirones, Cristina; Acosta, Felix; Icardo, Jose M.; Martínez-Martínez, Luis; Ramos-Vivas, José
Ceftaroline (CPT) is a novel cephalosporin with in vitro activity against Staphylococcus aureus. Ceftaroline exhibits a level of binding affinity for PBPs in S. aureus including PBP2a of methicillin-resistant S. aureus (MRSA). The aims of this study were to investigate the morphological, physiological and molecular responses of MRSA clinical strains and MRSA biofilms to sub-MICs (1/4 and 1/16 MIC) of ceftaroline by using transmission, scanning and confocal microscopy. We have also used quantitative Real-Time PCR to study the effect of sub-MICs of ceftaroline on the expression of the staphylococcal icaA, agrA, sarA and sasF genes in MRSA biofilms. In one set of experiments, ceftaroline was able to inhibit biofilm formation in all strains tested at MIC, however, a strain dependent behavior in presence of sub-MICs of ceftaroline was shown. In a second set of experiments, destruction of preformed biofilms by addition of ceftaroline was evaluated. Ceftaroline was able to inhibit biofilm formation at MIC in all strains tested but not at the sub-MICs. Destruction of preformed biofilms was strain dependent because the biofilm formed by a matrix-producing strain was resistant to a challenge with ceftaroline at MIC, whereas in other strains the biofilm was sensitive. At sub-MICs, the impact of ceftaroline on expression of virulence genes was strain-dependent at 1/4 MIC and no correlation between ceftaroline-enhanced biofilm formation and gene regulation was established at 1/16 MIC. Our findings suggest that sub-MICs of ceftaroline enhance bacterial attachment and biofilm formation by some, but not all, MRSA strains and, therefore, stress the importance of maintaining effective bactericidal concentrations of ceftaroline to fight biofilm-MRSA related infections. PMID:26800524
Hawes Alicia C
Full Text Available Abstract Background Community acquired (CA methicillin-resistant Staphylococcus aureus (MRSA increasingly causes disease worldwide. USA300 has emerged as the predominant clone causing superficial and invasive infections in children and adults in the USA. Epidemiological studies suggest that USA300 is more virulent than other CA-MRSA. The genetic determinants that render virulence and dominance to USA300 remain unclear. Results We sequenced the genomes of two pediatric USA300 isolates: one CA-MRSA and one CA-methicillin susceptible (MSSA, isolated at Texas Children's Hospital in Houston. DNA sequencing was performed by Sanger dideoxy whole genome shotgun (WGS and 454 Life Sciences pyrosequencing strategies. The sequence of the USA300 MRSA strain was rigorously annotated. In USA300-MRSA 2658 chromosomal open reading frames were predicted and 3.1 and 27 kilobase (kb plasmids were identified. USA300-MSSA contained a 20 kb plasmid with some homology to the 27 kb plasmid found in USA300-MRSA. Two regions found in US300-MRSA were absent in USA300-MSSA. One of these carried the arginine deiminase operon that appears to have been acquired from S. epidermidis. The USA300 sequence was aligned with other sequenced S. aureus genomes and regions unique to USA300 MRSA were identified. Conclusion USA300-MRSA is highly similar to other MRSA strains based on whole genome alignments and gene content, indicating that the differences in pathogenesis are due to subtle changes rather than to large-scale acquisition of virulence factor genes. The USA300 Houston isolate differs from another sequenced USA300 strain isolate, derived from a patient in San Francisco, in plasmid content and a number of sequence polymorphisms. Such differences will provide new insights into the evolution of pathogens.
Full Text Available BACKGROUND: The incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA infection is rising in the developed world but appears to be rare in developing countries. One explanation for this difference is that resource poor countries lack the diagnostic microbiology facilities necessary to detect the presence of CA-MRSA carriage and infection. METHODOLOGY AND PRINCIPAL FINDINGS: We developed diagnostic microbiology capabilities at the Angkor Hospital for Children, Siem Reap, western Cambodia in January 2006 and in the same month identified a child with severe community-acquired impetigo caused by CA-MRSA. A study was undertaken to identify and describe additional cases presenting between January 2006 and December 2007. Bacterial isolates underwent molecular characterization using multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec typing, and PCR for the presence of the genes encoding Panton-Valentine Leukocidin (PVL. Seventeen children were identified with CA-MRSA infection, of which 11 had skin and soft tissue infection and 6 had invasive disease. The majority of cases were unrelated in time or place. Molecular characterization identified two independent MRSA clones; fifteen isolates were sequence type (ST 834, SCCmec type IV, PVL gene-negative, and two isolates were ST 121, SCCmec type V, PVL gene-positive. CONCLUSIONS: This represents the first ever report of MRSA in Cambodia, spread of which would pose a significant threat to public health. The finding that cases were mostly unrelated in time or place suggests that these were sporadic infections in persons who were CA-MRSA carriers or contacts of carriers, rather than arising in the context of an outbreak.
Full Text Available BACKGROUND: The screening of hospital admission patients for methicillin resistant Staphylococcus aureus (MRSA is of undisputed value in controlling and reducing the overall MRSA burden; yet, a concerted parallel universal screening intervention throughout all hospitals of an entire German Federal State has not yet been performed. METHODOLOGY/PRINCIPAL FINDINGS: During a four-week period, all 24 acute care hospitals of the State of Saarland participated in admission prevalence screening. Overall, 436/20,027 screened patients revealed MRSA carrier status (prevalence, 2.2/100 patients with geriatrics and intensive care departments associated with highest prevalence (7.6/100 and 6.3/100, respectively. Risk factor analysis among 17,975 admission patients yielded MRSA history (OR, 4.3; CI₉₅ 2.7-6.8, a skin condition (OR, 3.2; CI₉₅ 2.1-5.0, and/or an indwelling catheter (OR, 2.2; CI₉₅ 1.4-3.5 among the leading risks. Hierarchical risk factor ascertainment of the six risk factors associated with highest odd's ratios would require 31% of patients to be laboratory screened to allow for detection of 67% of all MRSA positive admission patients in the State. CONCLUSIONS/SIGNIFICANCE: State-wide admission prevalence screening in conjunction with risk factor ascertainment yields important information on the distribution of the MRSA burden for hospitals, and allows for data-based decisions on local or institutional MRSA screening policies considering risk factor prevalence and expected MRSA identification rates.
Althaqafi, Abdulhakeem O; Matar, Madonna J; Moghnieh, Rima; Alothman, Adel F; Alenazi, Thamer H; Farahat, Fayssal; Corman, Shelby; Solem, Caitlyn T; Raghubir, Nirvana; Macahilig, Cynthia; Haider, Seema; Stephens, Jennifer M
Objectives The objective of this study is to describe the real-world treatment patterns and burden of suspected or confirmed methicillin-resistant Staphylococcus aureus (MRSA) pneumonia in Saudi Arabia and Lebanon. Methods A retrospective chart review study evaluated 2011–2012 data from hospitals in Saudi Arabia and Lebanon. Patients were included if they had been discharged with a diagnosis of MRSA pneumonia, which was culture proven or suspected based on clinical criteria. Hospital data were abstracted for a random sample of patients to capture demographics (eg, age and comorbidities), treatment patterns (eg, timing and use of antimicrobials), hospital resource utilization (eg, length of stay), and clinical outcomes (eg, clinical status at discharge and mortality). Descriptive results were reported using frequencies or proportions for categorical variables and mean and standard deviation for continuous variables. Results Chart-level data were collected for 93 patients with MRSA pneumonia, 50 in Saudi Arabia and 43 in Lebanon. The average age of the patients was 56 years, and 60% were male. The most common comorbidities were diabetes (39%), congestive heart failure (30%), coronary artery disease (29%), and chronic obstructive pulmonary disease (28%). Patients most frequently had positive cultures from pulmonary (87%) and blood (27%) samples. All isolates were sensitive to vancomycin, teicoplanin, and linezolid, and only one-third of the isolates tested were sensitive to ciprofloxacin. Beta-lactams (inactive therapy for MRSA) were prescribed 21% of the time across all lines of therapy, with 42% of patients receiving first-line beta-lactams. Fifteen percent of patients did not receive any antibiotics that were considered to be MRSA active. The mean hospital length of stay was 32 days, and in-hospital mortality was 30%. Conclusion The treatment for MRSA pneumonia in Saudi Arabia and Lebanon may be suboptimal with inactive therapy prescribed a substantial proportion
Ahmed, Mohamed O.; Abuzweda, Abdulbaset R.; Alghazali, Mohamed H.; Elramalli, Asma K.; Amri, Samira G.; Aghila, Ezzeddin Sh.; Abouzeed, Yousef M.
Background Methicillin-resistant Staphylococcus aureus (MRSA) is a nosocomial (hospital-acquired) pathogen of exceptional concern. It is responsible for life-threatening infections in both the hospital and the community. Aims To determine the frequency of MRSA misidentification in hospitals in Tripoli, Libya using current testing methods. Methods One hundred and seventy S. aureus isolates previously identified as MRSA were obtained from three hospitals in Tripoli. All isolates were reidentified by culturing on mannitol salt agar, API 20 Staph System and retested for resistance to methicillin using the cefoxitin disk diffusion susceptibility test and PBP2a. D-tests and vancomycin E-tests (Van-E-tests) were also performed for vancomycin-resistant isolates. Results Of the 170 isolates examined, 86 (51%) were confirmed as MRSA (i.e. 49% were misidentified as MRSA). Fifteen (17%) of the confirmed MRSA strains exhibited inducible clindamycin resistance. Of the 86 confirmed MRSA isolates, 13 (15%) were resistant to mupirocin, 53 (62%) were resistant to ciprofloxacin, 41 (48%) were resistant to trimethoprim-sulfamethoxazole, and none were resistant to linezolid. Although disc-diffusion testing indicated that 23 (27%) of the isolates were resistant to vancomycin, none of the isolates were vancomycin-resistant by Van-E-test. Conclusions Misidentification of nosocomial S. aureus as MRSA is a serious problem in Libyan hospitals. There is an urgent need for the proper training of microbiology laboratory technicians in standard antimicrobial susceptibility procedures and the implementation of quality control programs in microbiology laboratories of Libyan hospitals. PMID:21483574
Ueno, Tsuyoshi; Toyooka, Shinichi; Soh, Junichi; Miyoshi, Kentaroh; Sugimoto, Seiichiro; Yamane, Masaomi; Oto, Takahiro; Miyoshi, Shinichiro
OBJECTIVES Empyema is a well-known complication following lung resection. In particular, empyema caused by methicillin-resistant Staphylococcus aureus (MRSA) is difficult to treat. Here, we present our experience of MRSA empyema treated with local irrigation using arbekacin. METHODS Six patients consisted of 4 males and 2 females with an average age of 65.7 years. They developed MRSA empyema following lung resection and were treated at our institution between 2007 and 2011. Cases comprised four primary and one metastatic lung cancer, and 1 patient was a living lung transplantation donor. The surgical procedure consisted of four lobectomies, one segmentectomy and one wedge resection. After diagnosis of MRSA empyema, anti-MRSA drugs were administered intravenously in all cases. In addition, arbekacin irrigation at a dose of 100 mg dissolved in saline was performed after irrigation with saline only. RESULTS The average number of postoperative days for the diagnosis of MRSA empyema was 13 (range 4–19). The period of irrigation ranged from 6 to 46 days. Arbekacin irrigation did not induce nephrotoxicity or other complications, and no bacteria resistant to arbekacin was detected in the thoracic cavity. We re-operated on 1 case because he had pulmonary fistula and severe wound infection. At the time of removing the thoracic catheter, MRSA in the pleural effusion disappeared completely in 3 patients. The period until MRSA concentration in the pleural effusion became negative after starting arbekacin irrigation ranged from 4 to 9 days. In the remaining cases, in which MRSA did not disappear, the catheter was removed because of no inflammatory reaction after stopping irrigation and clamping the catheters. All patients were discharged from our institution without thoracic catheterization and no patients had relapsed during the follow-up period ranging from 6 to 44 months. CONCLUSIONS Irrigation of the thoracic cavity with arbekacin proved to be an effective, safe and
Full Text Available BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA infection is an important public health issue. The study aimed to determine the prevalence of ocular infections caused by MRSA and to identify the clinical characteristics and antibiotic susceptibility of ocular MRSA infections by comparing those of ocular methicillin-sensitive S. aureus (MSSA infections. METHODOLOGY/PRINCIPAL FINDINGS: The medical records of the patients (n = 519 with culture-proven S. aureus ocular infections seen between January 1, 1999 and December 31, 2008 in Chang Gung Memorial Hospital were retrospectively reviewed. Two hundred and seventy-four patients with MRSA and 245 with MSSA ocular infections were identified. The average rate of MRSA in S. aureus infections was 52.8% and the trend was stable over the ten years (P value for trend = 0.228. MRSA ocular infections were significantly more common among the patients with healthcare exposure (P = 0.024, but 66.1% (181/274 patients with MRSA ocular infections had no healthcare exposure. The most common clinical presentation for both MRSA and MSSA ocular infections was keratitis; MRSA and MSSA caused a similar disease spectrum except for lid infections. MRSA was significantly more resistant than MSSA to clindamycin, erythromycin and sulfamethoxazole/trimethoprim (all P<0.001. CONCLUSIONS/SIGNIFICANCE: We demonstrated a paralleled trend of ocular MRSA infection in a highly prevalent MRSA country by hospital-based survey. Except for lid disorder, MRSA shared similar spectrum of ocular pathology with MSSA. Since S. aureus is a common ocular pathogen, our results raise clinician's attention to the existence of highly prevalent MRSA.
Foucault, Marie-Laure; Courvalin, Patrice; Grillot-Courvalin, Catherine
We have quantified the biological cost of VanA-type glycopeptide resistance due to the acquisition of the resistance operon by methicillin-resistant Staphylococcus aureus (MRSA) from Enterococcus sp. Exponential growths of recipient strain HIP11713, its transconjugant VRSA-1, VRSA-5, and VRSA-6 were compared in the absence or, except for HIP11713, in the presence of vancomycin. Induction of resistance was performed by adding vancomycin in both the preculture and the culture or the culture at only 1/50 the MIC. In the absence of vancomycin, the growth rates of the vancomycin-resistant S. aureus (VRSA) strains were similar to that of susceptible MRSA strain HIP11713. When resistance was induced, and under both conditions, there was a significant reduction of the growth rate of the VRSA strains relative to that of HIP11713 and to those of their noninduced counterparts, corresponding to a ca. 20% to 38% reduction in fitness. Competition experiments between isogenic VRSA-1 and HIP11713 mixed at a 1:1, 1:100, or 100:1 ratio revealed a competitive disadvantage of 0.4% to 3% per 10 generations of the transconjugant versus the recipient. This slight fitness burden can be attributed to the basal level of expression of the van genes in the absence of induction combined with a gene dosage effect due to the presence of the van operon on multicopy plasmids. These data indicate that VanA-type resistance, when induced, is highly costly for the MRSA host, whereas in the absence of induction, its biological cost is minimal. Thus, the potential for the dissemination of VRSA clinical isolates should not be underestimated.
Hamed Haddad Kashani
Full Text Available Cysteine/histidine-dependent amidohydrolase/peptidase (CHAP and amidase are known as catalytic domains of the bacteriophage-derived endolysin LysK and were previously reported to show lytic activity against methicillin-resistant Staphylococcus aureus (MRSA. In the current study, the in silico design and analysis of chimeric CHAP-amidase model was applied to enhance the stability and solubility of protein, which was achieved through improving the properties of primary, secondary and tertiary structures. The coding gene sequence of the chimeric CHAP-amidase was synthesized and subcloned into the pET-22(+ expression vector, and the recombinant protein was expressed in E. coli BL21 (DE3 strain. Subsequent affinity-based purification yielded ~12 mg soluble protein per liter of E. coli culture. Statistical analysis indicated that concentrations of ≥1 μg/mL of the purified protein have significant antibacterial activity against S. aureus MRSA252 cells. The engineered chimeric CHAP-amidase exhibited 3.2 log reduction of MRSA252 cell counts at the concentration of 10 μg/mL. A synergistic interaction between CHAP-amidase and vancomycin was detected by using checkerboard assay and calculating the fractional inhibitory concentration (FIC index. This synergistic effect was shown by 8-fold reduction in the minimum inhibitory concentration of vancomycin. The chimeric CHAP-amidase displayed strong antibacterial activity against S. aureus, S. epidermidis, and enterococcus. However, it did not indicate any significant antibacterial activity against E. coli and Lactococcus lactis. Taken together, these findings suggest that our chimeric CHAP-amidase might represent potential to be used for the development of efficient antibacterial therapies targeting MRSA and certain Gram-positive bacteria.
Full Text Available Introduction Infections caused by methicillin-resistant Staphylococcus aureus (MRSA present the growing problem in the whole world. Carriage of MRSA is most frequent in the nose, and medical students come in contact both with patients and different persons in the community. Therefore, they may be significant for the transmission of MRSA from hospitals to out- of-hospital communities and vice versa. Objective. The aim of this study was to establish the carriage rate among students of the second, third and fourth year of study at the School of Medicine in Belgrade and to analyze their genotypic and phenotypic characteristics. Methods. In total 533 nasal samples were taken. The samples were incubated in Trypcase-soy broth supplemented with 6.5% NaCl, and thereafter the swabs were inoculated on mannitol salt agar supplemented with 2 µg/mL of oxacillin. The presence of nuc, mecA and Panton-Valentine leukocidin genes was examined by PCR. The characteristics of the MRSA strains were determined using: antibiotic susceptibility testing by Vitek2 System, SCCmec, agr typing and MLST. Results. MRSA was isolated from two of 533 investigated samples (0.37%. MRSA were isolated from the students of the second and third year of study. Profiles of strains were: ST80 (SCCmec type IV, agr type 3 and ST152 (SCCmec type V, agr type 1. MRSA strains were multiresistant. Conclusion. The nasal carriage rate of MRSA in population of medical students of the first year of study in Belgrade is low. Genotypic and phenotypic characteristics of MRSA strains indicate their community origin. MLST typing revealed that isolates belong to ST80 and ST152. [Projekat Ministarstva nauke Republike Srbije, br. ON175039
Street, Cale N.; Pedigo, Lisa; Gibbs, Aaron; Loebel, Nicolas G.
The nosocomial infection rate has increased dramatically due to emergence of antibiotic resistant bacterial strains such as methicillin resistant Staphylococcus aureus (MRSA). The primary anatomical site of MRSA colonization is the anterior nares, and this reservoir represents a primary vector of transmission from non-infected carriers to susceptible individuals. Antimicrobial photodynamic therapy (aPDT) has been used successfully for topical disinfection in the oral cavity. The aim of this study was to evaluate the utility of aPDT for nasal MRSA decolonization at the preclinical and clinical level. The nasal aPDT system consists of a 670 nm diode laser fibre-optically coupled to a disposable light diffusing tip, used to activate a methylene blue based photosensitizer formulation. Preclinical testing was done both in a custom nasal reservoir model and on human skin cultures colonized on the epithelial surface with MRSA. Human clinical testing was performed by clinicians in regions in which the system is approved by the regulatory authority. In vitro testing demonstrated that aPDT eradicated planktonic MRSA in an energy and photosensitizer concentration dependent manner. Furthermore, aPDT eliminated sustained colonization of MRSA on cultured human epithelial surfaces, an effect that was sustained over multiple days post-treatment. In preliminary human testing, aPDT eradicated MRSA completely from the nose with total treatment times <10 minutes. aPDT is effective against MRSA when used topically in the nose. Energy dose and photosensitizer parameters have been optimized for the nasal environment. Controlled clinical studies are currently underway to further evaluate safety and efficacy.
Nishith Kumar Pal
Full Text Available Objective: To explore the in vitro antibacterial activity of ethanolic extracts of cinnamon (Cinnamomum zeylanicum; CIN, clove (Syzygium aromaticum, CLV and cumin (Cuminum cyminum, CMN against clinical isolates of methicillin resistant Staphylococcus aureus (MRSA, from Kolkata, India.Methods: The CIN, CLV and CMN were tested for their antibacterial activity against MRSA by in vitro methods. Minimum inhibitory concentration (MIC values of the three extracts were determined, and time-kill studies were performed in order to investigate the bactericidal activity of the extracts (at the MIC level for the isolates. The killing efficacy of the extracts was determined at various concentrations.Results: The zone diameter of inhibition (ZDI obtained due to CIN, CLV and CMN ranged between 22-27 mm, 19-23 mm and 9-15 mm, respectively; while the MICs, for the isolates, were in the range of 64-256, 64-512 and 128-512 µg/ml, respectively. When tested for their MIC levels; the CIN and CLV were found to be bactericidal after 6 hrs of incubation, while CMN showed bactericidal activity after 24 hrs. However, when tested at various concentrations; CIN, CLV and CMN displayed bactericidal activity against S. aureus, after 24 hrs of incubation, at 200, 200 and 300 µg/ml, respectively.Conclusion: The C. zeylanicum and S. aromaticum showed the strongest in vitro antibacterial activity followed by C. cyminum against MRSA, and such findings could be considered a valuable support in the treatment of infection and may contribute to the development of potential antimicrobial agents for inclusion in anti- S. aureus regimens.
Buultjens, Andrew H.; Giulieri, Stefano; Owusu-Mireku, Evelyn; Aboagye, Samuel Y.; Baines, Sarah L.; Gonçalves da Silva, Anders; Howden, Benjamin P.; Pluschke, Gerd; Yeboah-Manu, Dorothy
Background The emergence and evolution of community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) strains in Africa is poorly understood. However, one particular MRSA lineage called ST88, appears to be rapidly establishing itself as an “African” CA-MRSA clone. In this study, we employed whole genome sequencing to provide more information on the genetic background of ST88 CA-MRSA isolates from Ghana and to describe in detail ST88 CA-MRSA isolates in comparison with other MRSA lineages worldwide. Methods We first established a complete ST88 reference genome (AUS0325) using PacBio SMRT sequencing. We then used comparative genomics to assess relatedness among 17 ST88 CA-MRSA isolates recovered from patients attending Buruli ulcer treatment centres in Ghana, three non-African ST88s and 15 other MRSA lineages. Results We show that Ghanaian ST88 forms a discrete MRSA lineage (harbouring SCCmec-IV [2B]). Gene content analysis identified five distinct genomic regions enriched among ST88 isolates compared with the other S. aureus lineages. The Ghanaian ST88 isolates had only 658 core genome SNPs and there was no correlation between phylogeny and geography, suggesting the recent spread of this clone. The lineage was also resistant to multiple classes of antibiotics including β-lactams, tetracycline and chloramphenicol. Discussion This study reveals that S. aureus ST88-IV is a recently emerging and rapidly spreading CA-MRSA clone in Ghana. The study highlights the capacity of small snapshot genomic studies to provide actionable public health information in resource limited settings. To our knowledge this is the first genomic assessment of the ST88 CA-MRSA clone. PMID:28265515
Full Text Available Staphylococcus aureus is a typical human pathogen. Some animal S. aureus lineages have derived from human strains following profound genetic adaptation determining a change in host specificity. Due to the close relationship of animals with the environmental microbioma and resistoma, animal staphylococcal strains also represent a source of resistance determinants. Methicillin-resistant S. aureus (MRSA emerged fifty years ago as a nosocomial pathogen but in the last decade it has also become a frequent cause of infections in the community. The recent finding that MRSA frequently colonizes animals, especially livestock, has been a reason for concern, as it has revealed an expanded reservoir of MRSA. While MRSA strains recovered from companion animals are generally similar to human nosocomial MRSA, MRSA strains recovered from food animals appear to be specific animal-adapted clones. Since 2005, MRSA belonging to ST398 was recognized as a colonizer of pigs and human subjects professionally exposed to pig farming. The pig MRSA was also found to colonize other species of farmed animals, including horses, cattle and poultry and was therefore designated livestock-associated (LA-MRSA. LA-MRSA ST398 can cause infections in humans in contact with animals, and can infect hospitalized people, although at the moment this occurrence is relatively rare. Other animal-adapted MRSA clones have been detected in livestock, such as ST1 and ST9. Recently, ST130 MRSA isolated from bovine mastitis has been found to carry a novel mecA gene that eludes detection by conventional PCR tests. Similar ST130 strains have been isolated from human infections in UK, Denmark and Germany at low frequency. It is plausible that the increased attention to animal MRSA will reveal other strains with peculiar characteristics that can pose a risk to human health.
Juan Manuel J. Favela-Hernández
Full Text Available Bacterial infections represent one of the main threats to global public health. One of the major causative agents associated with high morbidity and mortality infections in hospitals worldwide is methicillin-resistant Staphylococcus aureus. Therefore, there is a need to develop new antibacterial agents to treat these infections, and natural products are a rich source of them. In previous studies, we reported that lignan 3′-demethoxy-6-O-demethylisoguaiacin, isolated and characterized from Larrea tridentate, showed the best activity towards methicillin-resistant S. aureus. Thus, the aim of this study was to determine the potential molecular mechanism of the antibacterial activity of 3′-demethoxy-6-O-demethylisoguaiacin against methicillin-resistant S. aureus using microarray technology. Results of microarray genome expression were validated by real-time polymerase chain reaction (RT-PCR. The genetic profile expression results showed that lignan 3′-demethoxy-6-O-demethylisoguaiacin had activity on cell membrane affecting proteins of the ATP-binding cassette (ABC transport system causing bacteria death. This molecular mechanism is not present in any antibacterial commercial drug and could be a new target for the development of novel antibacterial agents.
Full Text Available This study aimed to correlate the presence of ica genes, biofilm formation and antimicrobial resistance in 107 strains of Staphylococcus epidermidis isolated from blood cultures. The isolates were analysed to determine their methicillin resistance, staphylococcal cassette chromosome mec (SCCmec type, ica genes and biofilm formation and the vancomycin minimum inhibitory concentration (MIC was measured for isolates and subpopulations growing on vancomycin screen agar. The mecA gene was detected in 81.3% of the S. epidermidis isolated and 48.2% carried SCCmec type III. The complete icaADBC operon was observed in 38.3% of the isolates; of these, 58.5% produced a biofilm. Furthermore, 47.7% of the isolates grew on vancomycin screen agar, with an increase in the MIC in 75.9% of the isolates. Determination of the MIC of subpopulations revealed that 64.7% had an MIC ≥ 4 μg mL-1, including 15.7% with an MIC of 8 μg mL-1 and 2% with an MIC of 16 μg mL-1. The presence of the icaADBC operon, biofilm production and reduced susceptibility to vancomycin were associated with methicillin resistance. This study reveals a high level of methicillin resistance, biofilm formation and reduced susceptibility to vancomycin in subpopulations of S. epidermidis. These findings may explain the selection of multidrug-resistant isolates in hospital settings and the consequent failure of antimicrobial treatment.
Ashizawa, Nobuyuki; Tsuji, Yasuhiro; Kawago, Koyomi; Higashi, Yoshitsugu; Tashiro, Masato; Nogami, Makiko; Gejo, Ryuichi; Narukawa, Munetoshi; Kimura, Tomoatsu; Yamamoto, Yoshihiro
Linezolid is an effective antibiotic against most gram-positive bacteria including drug-resistant strains such as methicillin-resistant Staphylococcus aureus. Although linezolid therapy is known to result in thrombocytopenia, dosage adjustment or therapeutic drug monitoring of linezolid is not generally necessary. In this report, however, we describe the case of a 79-year-old woman with recurrent methicillin-resistant S. aureus osteomyelitis that was successfully treated via surgery and combination therapy using linezolid and rifampicin under therapeutic drug monitoring for maintaining an appropriate serum linezolid concentration. The patient underwent surgery for the removal of the artificial left knee joint and placement of vancomycin-impregnated bone cement beads against methicillin-resistant S. aureus after total left knee implant arthroplasty for osteoarthritis. We also initiated linezolid administration at a conventional dose of 600 mg/h at 12-h intervals, but reduced it to 300 mg/h at 12-h intervals on day 9 because of a decrease in platelet count and an increase in serum linezolid trough concentration. However, when the infection exacerbated, we again increased the linezolid dose to 600 mg/h at 12-h intervals and performed combination therapy with rifampicin, considering their synergistic effects and the control of serum linezolid trough concentration via drug interaction. Methicillin-resistant S. aureus infection improved without reducing the dose of or discontinuing linezolid. The findings in the present case suggest that therapeutic drug monitoring could be useful for ensuring the therapeutic efficacy and safety of combination therapy even in patients with osteomyelitis who require long-term antibiotic administration.
Maria Elena Velázquez-Meza
Full Text Available Las infecciones nosocomiales ocasionadas por cepas de Staphylococcus aureus meticilinorresistentes (SAMR son un problema de salud importante en todo el mundo. Este microorganismo produce una gran variedad de infecciones incluyendo osteomielitis, endocarditis invasora, artritis séptica y septicemia. La multirresistencia es un factor que influye en la persistencia de los SAMR dentro del ámbito hospitalario. La introducción de técnicas de tipificación molecular dentro de las investigaciones epidemiológicas ha provisto nuevas herramientas para conocer el origen y las vías de diseminación de este microorganismo. Una de las conclusiones importantes que han surgido de este tipo de estudios es que un número pequeño de clonas son las responsables de las infecciones estafilocócicas en todo el mundo.Nosocomial infections due to methicillin-resistant Staphylococcus aureus (MRSA is an important health problem worldwide. This microorganism causes a variety of clinical infections, including osteomyelitis, invasive endocarditis, septic arthritis and septicemia. Antimicrobial resistance is a factor that influences the persistence of MRSA in the hospital environment. The introduction of molecular typing techniques in epidemiological investigations has provided new tools for identifying the microorganism's origin and routes of dissemination. One of the most important conclusions that have resulted from these types of studies is that a small number of clones are responsible for most of the staphylococcal infections throughout the world.
Gómez, Paula; Lozano, Carmen; Benito, Daniel; Estepa, Vanesa; Tenorio, Carmen; Zarazaga, Myriam; Torres, Carmen
The objective of this study was to determine the prevalence of Staphylococcus in urban wastewater treatment plants (UWTP) of La Rioja (Spain), and to characterize de obtained isolates. 16 wastewater samples (8 influent, 8 effluent) of six UWTPs were seeded on mannitol-salt-agar and oxacillin-resistance-screening-agar-base for staphylococci and methicillin-resistant Staphylococcus aureus recovery. Antimicrobial susceptibility profile was determined for 16 antibiotics and the presence of 35 antimicrobial resistance genes and 14 virulence genes by PCR. S. aureus was typed by spa, agr, and multilocus-sequence-typing, and the presence of immune-evasion-genes cluster was analyzed. Staphylococcus spp. were detected in 13 of 16 tested wastewater samples (81%), although the number of CFU/mL decreased after treatment. 40 staphylococci were recovered (1-5/sample), and 8 of them were identified as S. aureus being typed as (number of strains): spa-t011/agr-II/ST398 (1), spa-t002/agr-II/ST5 (2), spa-t3262/agr-II/ST5 (1), spa-t605/agr-II/ST126 (3), and spa-t878/agr-III/ST2849 (1). S. aureus ST398 strain was methicillin-resistant and showed a multidrug resistance phenotype. Virulence genes tst, etd, sea, sec, seg, sei, sem, sen, seo, and seu, were detected among S. aureus and only ST5 strains showed genes of immune evasion cluster. Thirty-two coagulase-negative Staphylococcus of 12 different species were recovered (number of strains): Staphylococcus equorum (7), Staphylococcus vitulinus (4), Staphylococcus lentus (4), Staphylococcus sciuri (4), Staphylococcus fleurettii (2), Staphylococcus haemolyticus (2), Staphylococcus hominis (2), Staphylococcus saprophyticus (2), Staphylococcus succinus (2), Staphylococcus capitis (1), Staphylococcus cohnii (1), and Staphylococcus epidermidis (1). Five presented a multidrug resistance phenotype. The following resistance and virulence genes were found: mecA, lnu(A), vga(A), tet(K), erm(C), msr(A)/(B), mph(C), tst, and sem. We found that
Full Text Available Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA has become increasingly prevalent worldwide since it was first reported in a British hospital. The prevalence however, varies markedly in hospitals in the same country, and from one country to another. We therefore sought to document comprehensively the prevalence and antimicrobial susceptibility pattern of MRSA isolates in Trinidad and Tobago. Methods All Staphylococcus aureus isolates encountered in routine clinical specimens received at major hospitals in the country between 2000 and 2001 were identified morphologically and biochemically by standard laboratory procedures including latex agglutination test (Staphaurex Plus; Murex Diagnostics Ltd; Dartford, England; tube coagulase test with rabbit plasma (Becton, Dickinson & Co; Sparks, MD, USA, and DNase test using DNase agar (Oxoid Ltd; Basingstoke, Hampshire, England. MRSA screening was performed using Mueller-Hinton agar containing 6 μg oxacillin and 4% NaCl, latex agglutination test (Denka Seiken Co. Ltd, Tokyo, Japan and E-test system (AB Biodisk, Solna, Sweden. Susceptibility to antimicrobial agents was determined by the modified Kirby Bauer disc diffusion method while methicillin MICs were determined with E-test system. Results Of 1,912 S. aureus isolates received, 12.8% were methicillin (oxacillin resistant. Majority of the isolates were recovered from wound swabs (86.9% and the least in urine (0.4% specimens. Highest number of isolates was encountered in the surgical (62.3% and the least from obstetrics and gynaecology (1.6% facilities respectively. Large proportions of methicillin sensitive isolates are >85% sensitive to commonly used and available antimicrobials in the country. All MRSA isolates were resistant to ceftriaxone, erythromycin, gentamicin and penicillin but were 100% sensitive to vancomycin, rifampin and chloramphenicol. Conclusion There is a progressive increase in MRSA prevalence in the country but
Full Text Available John Chipolombwe,1 Mili Estee Török,2 Nontombi Mbelle,3 Peter Nyasulu,4,51Department of Internal Medicine, Mzuzu Central Hospital, Ministry of Health, Mzuzu, Malawi; 2Department of Medicine, University of Cambridge, Cambridge, UK; 3Department of Medical Microbiology, University of Pretoria, Pretoria, South Africa; 4School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 5Department of Public Health, School of Health Sciences, Monash University, Johannesburg, South Africa Purpose: The objective of this study was to evaluate the optimal number of sampling sites for detection of methicillin-resistant Staphylococcus aureus (MRSA colonization. Methods: We performed a Medline search from January 1966 to February 2014 for articles that reported the prevalence of MRSA at different body sites. Studies were characterized by study design, country and period of the study, number of patients and/or isolates of MRSA, specimen type, sites of MRSA isolation, study population sampled, diagnostic testing method, and percentage of the MRSA isolates at each site in relation to the total number of sites. Results: We reviewed 3,211 abstracts and 177 manuscripts, of which 17 met the criteria for analysis (n=52,642 patients. MRSA colonization prevalence varied from 8% to 99% at different body sites. The nasal cavity as a single site had MRSA detection sensitivity of 68% (34%–91%.The throat and nares gave the highest detection rates as single sites. A combination of two swabs improved MRSA detection rates with the best combination being groin/throat (89.6%; 62.5%–100%. A combination of three swab sites improved MRSA detection rate to 94.2% (81%–100% with the best combination being groin/nose/throat. Certain combinations were associated with low detection rates. MRSA detection rates also varied with different culture methods. Conclusion: A combination of three swabs from different body sites resulted in the highest detection rate for
Co-infection of methicillin-resistant Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus and extended spectrum β-lactamase producing Escherichia coli in bovine mastitis--three cases reported from India.
Bandyopadhyay, Samiran; Samanta, Indranil; Bhattacharyya, Debaraj; Nanda, Pramod Kumar; Kar, Debasish; Chowdhury, Jayanta; Dandapat, Premanshu; Das, Arun Kumar; Batul, Nayan; Mondal, Bimalendu; Dutta, Tapan Kumar; Das, Gunjan; Das, Bikash Chandra; Naskar, Syamal; Bandyopadhyay, Uttam Kumar; Das, Suresh Chandra; Bandyopadhyay, Subhasish
Emergence of antimicrobial resistance among bovine mastitis pathogens is the major cause of frequent therapeutic failure and a cause of concern for veterinary practitioners. This study describes intra-mammary infection of methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum β-lactamase (ESBL) producing Escherichia coli in two Holstein Friesian crossbred cows with subclinical mastitis and one non-descript cow with clinical mastitis in two different districts of West Bengal, India. In total, three MRSE, one MRSA and three ESBL producing E. coli were isolated from these cases. Both the crossbreds were detected with MRSE (HFSE1 and HFSE2) and ESBL producing E. coli (HFEC1 and HFEC2), whereas, simultaneous infection of three pathogens viz. MRSA (NDSA1), MRSE (NDSE1) and ESBL producing E. coli (NDEC1) was found in the non-descript cow. The methicillin-resistant isolates possessed mecA gene and exhibited resistance to various antibiotics such as amikacin, tetracycline and glycopeptides. The ESBL producers were positive for blaCTX-M and blaTEM genes; in addition, HFEC1 and HFEC2 were positive for blaSHV and possessed the genes for class I integron (int1), sulphonamide resistance (sul1), quinolone resistance (qnrS) and other virulence factors (papC, iucD and ESTA1). All the ESBL producers exhibited resistance to a variety of antibiotics tested including third- and fourth-generation cephalosporins and were also intermediately resistant to carbapenems. This is the first ever report on simultaneous occurrence of MRSE, MRSA and ESBL producing E. coli in bovine mastitis indicating a major concern for dairy industry and public health as well.
Shiokawa, Yuichi; Nakashima, Atsuhiro; Tanoue, Yoshihisa; Tominaga, Ryuji
We report a very rare case of successful surgical treatment for methicillin-resistant Staphylococcus aureus endocarditis on the Dacron patch utilized for ventricular rerouting in a Rastelli operation. Vegetations were found on the right side of the patch associated with a large laceration. The patient underwent removal of the patch followed by reventricular rerouting and replacement of the right ventricle to pulmonary artery conduit. The postoperative course was uneventful. To the best of our knowledge, this is the first reported case of postoperative infective endocarditis on this location.
Bartels, M.D.; Nanuashvili, A.; Boye, K.;
The purpose of this study was to characterise methicillin-resistant Staphylococcus aureus (MRSA) isolates from the Republic of Georgia, part of the former Soviet Union. Thirty-two non-duplicate MRSA isolates were collected in the period from May 2006 to February 2007. The patient data were analysed...... and the isolates were characterised by staphylococcal protein A (spa) typing, staphylococcal chromosome cassette mec (SCCmec) typing, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE) and the detection of Panton-Valentine leukocidin (PVL) genes. Only two closely related spa types were...
Adnalizawati, A. Siti Noor; Nazlina, I.; Yaacob, W. A.
The in vitro activity of methanolic extract from Phyllanthus columnaris stem bark was studied against Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300 and MRSA BM1 (clinical strain) using time-kill curves in conjunction with scanning and transmission electron microscopy. The extract showed more markedly bactericidal activity in MRSA BM1 clinical strain within less than 4 h by 6.25-12.5 mg/mL and within 6 h by 1.56 mg/mL. Scanning electron microscopy of MRSA BM1 revealed distortion of cell whilst transmission electron microscopy revealed disruption in cell wall division.
Clock, Sarah A; Jia, Haomiao; Patel, Sameer; Ferng, Yu-Hui; Alba, Luis; Whittier, Susan; DeLaMora, Patricia; Tabibi, Setareh; Perlman, Jeffrey; Paul, David; Zaoutis, Theoklis; Larson, Elaine; Saiman, Lisa
Rates of colonization with methicillin-resistant Staphylococcus aureus (MRSA) and/or vancomycin-resistant enterococci (VRE) were determined for 1320 infants within 7 days of neonatal intensive care unit discharge. Overall, 4% and 1% of the infants were colonized with MRSA or VRE, respectively. Predictors identified in fixed-effects models were surgery during hospitalization (for MRSA colonization) and prolonged antimicrobial treatment (for VRE colonization). © The Author 2017. Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society. All rights reserved. For permissions, please e-mail: firstname.lastname@example.org.
Adnalizawati, A. Siti Noor; Nazlina, I. [School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Yaacob, W. A. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)
The in vitro activity of methanolic extract from Phyllanthus columnaris stem bark was studied against Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300 and MRSA BM1 (clinical strain) using time-kill curves in conjunction with scanning and transmission electron microscopy. The extract showed more markedly bactericidal activity in MRSA BM1 clinical strain within less than 4 h by 6.25-12.5 mg/mL and within 6 h by 1.56 mg/mL. Scanning electron microscopy of MRSA BM1 revealed distortion of cell whilst transmission electron microscopy revealed disruption in cell wall division.
Full Text Available 371 samples from meat and meat-environments were collected and examined for the detection of methicillin-resistant Staphylococcus aureus (MRSA. The structural gene for penicillin-binding protein 2a (mecA gene, was amplified by PCR and detected by agarose gel electrophoresis. 96 samples (25.8%, contained S. aureus and 2 of them (2.08% were mecA positive. Further assays are necessary to evaluate the spread of MRSA in food and food-environments.
Golding, George R; Bryden, Louis; Levett, Paul N; McDonald, Ryan R; Wong, Alice; Graham, Morag R; Tyler, Shaun; Van Domselaar, Gary; Mabon, Philip; Kent, Heather; Butaye, Patrick; Smith, Tara C; Kadlec, Kristina; Schwarz, Stefan; Weese, Scott J; Mulvey, Michael R
Despite reports of high colonization rates of ST398 livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) among pigs and pig farmers, the incidence of LA-MRSA infection in the general population in Canada appears to be rare in comparison to that in some European countries. In this study, the complete genome sequence of a Canadian representative LA-MRSA isolate (08BA02176) from a human postoperative surgical site infection was acquired and compared to the sequenced genome of an LA-MRSA isolate (S0385) from Europe to identify genetic traits that may explain differences in the success of these particular strains in some locales.
Udumula, Venkatareddy; Endres, Jennifer L; Harper, Caleb N; Jaramillo, Lee; Zhong, Haizhen A; Bayles, Kenneth W; Conda-Sheridan, Martin
Community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) has become a severe health concern because of its treatment difficulties. Herein, we report the synthesis and biological evaluation of two phenazine natural products and a series of phenazines that show promising activities against MRSA with MIC values in the low micromolar range. Basic studies revealed that these compounds are bacteriostatic agents. The most active compound also displayed promising IC50 values against HaCat cells. Finally, a QSAR model was developed to understand the key structural features of the molecules.
Al-Talib, Hassanain; Yean, Chan Yean; Hasan, Habsah; Nik Zuraina, N M N; Ravichandran, Manickam
Staphylococcus aureus nasal carriage is a common source of nosocomial infection and colonization. The aim of the present study was to assess the burden of methicillin-resistant S. aureus nasal carriage, its association with factors of interest including its genetic relationships. The prevalence of S. aureus nasal carriage was found to be 28.7%. This study showed that patients with a history of previous antibiotic intake, nasogastric tube, and longer hospitalization had a significantly high risk of being MRSA nasal carriers. The genetic relationship of all 34 nasal MRSA isolates revealed four major clusters of isolates, and there was a relationship between MRSA isolated from inpatients and healthcare workers.
Reduced graphene oxide (rGO)-modified glassy carbon electrode is used to detect the methicillin-resistant Staphylococcus aureus (MRSA) DNA by using electrochemical impedance spectroscopy. Our experiments confirm that ssDNA, before and after hybridization with target DNA, are successfully anchored on the rGO surface. After the probe DNA, pre-adsorbed on rGO electrode, hybridizes with target DNA, the measured impedance increases dramatically. It provides a new method to detect DNA with high sensitivity (10-13M, i.e., 100 fM) and selectivity. © 2011 Elsevier B.V.
Shiba, Mikio; Maeda, Hideaki; Shiono, Motomi
A 40-year-old man underwent ascending aorta replacement for an acute type A aortic dissection. After the operations, methicillin-resistant Staphylococcus aureus was identified in sputum and blood cultures. Although anti-methicillin-resistant Staphylococcus aureus drugs were administered, most of the intermittent blood cultures remained positive. The focus of methicillin-resistant Staphylococcus aureus infection was not evident in the early stages, and no specific symptoms such as abscess or endocarditis were observed. However, abscesses in the brain, mediastinum and spleen were found 3 years after the operation. The minimum inhibitory concentration of vancomycin gradually increased from 1 to 4 µg/mL during the course of treatment. This case provides evidence for a potential role of combination therapy. PMID:27489691
Full Text Available A 40-year-old man underwent ascending aorta replacement for an acute type A aortic dissection. After the operations, methicillin-resistant Staphylococcus aureus was identified in sputum and blood cultures. Although anti-methicillin-resistant Staphylococcus aureus drugs were administered, most of the intermittent blood cultures remained positive. The focus of methicillin-resistant Staphylococcus aureus infection was not evident in the early stages, and no specific symptoms such as abscess or endocarditis were observed. However, abscesses in the brain, mediastinum and spleen were found 3 years after the operation. The minimum inhibitory concentration of vancomycin gradually increased from 1 to 4 µg/mL during the course of treatment. This case provides evidence for a potential role of combination therapy.
Kipre, B G; Guessennd, N K; Koné, M W; Gbonon, V; Coulibaly, J K; Dosso, M
Tieghemella heckelii (Sapotaceae) is a medicinal plant used in Africa, particularly in Côte d'Ivoire for treating various diseases including infections. Identification of prospective antibacterial compounds from stem bark of this plant as a result of its medicinal virtue, led to screening activity against methicillin resistant bacteria. Six extracts (hexane, chloroform, ethyl acetate, ethanol, methanol and sterile distilled water) were prepared and tested on methicillin resistant Staphylococcus aureus (MRSA) using broth microdilution method for activity assessment. From this experiment, the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of the plant extracts were determined in sterile 96-well microplates in order to search for both bacteriostatic and bactericidal effects. Afterwards, data analysis was performed using GraphPad Prism5 software (One-way ANOVA and Turkey Multiple Comparison test). The results were then presented as Mean ± SD for experiment repeated three times. Four extracts (ethyl acetate, methanol, ethanol and sterile distilled water) showed credible potency, with strong, significant, and moderate growth inhibition of the MRSA tested. The MIC values which varied from 45 μg/mL to 97 μg/mL according to microbial phenotype, resolutely established the activity of the plant extracts. Additionally, the MBC values which varied, depending on the type of bacteria strain, revealed the bacteriostatic and bactericidal effects of the active extracts against Methicillin-resistant Staphylococcus aureus. The present study is a confirmation of the therapeutic potential of Tieghemella heckelii and its promising contribution to the discovery of a novel antibacterial drug pertaining to these resistant strains.
O'Mahony, R; Abbott, Y; Leonard, F C; Markey, B K; Quinn, P J; Pollock, P J; Fanning, S; Rossney, A S
Reports of methicillin-resistant Staphylococcus aureus (MRSA) in animals have become more frequent in recent years. This paper documents the recovery of MRSA from animals with respiratory, urinary tract or wound infection and from animals subjected to surgical procedures following treatment in one veterinary hospital and 16 private veterinary clinics in different geographical locations throughout Ireland. MRSA was recovered from 25 animals comprising 14 dogs, eight horses, one cat, one rabbit and a seal, and also from 10 attendant veterinary personnel. Clinical susceptibility testing suggested that the 35 isolates fell into two different groups. One group of isolates (Group 1) was resistant to one or more of the following classes of antimicrobials: macrolides, lincosamines, tetracyclines and/or fluoroquinolones. The second group (Group 2) was resistant to macrolides, aminoglycosides, tetracyclines and trimethoprim/sulphamethoxazole and variably resistant to fluoroquinolones, lincosamines and rifampicin. One isolate in Group 2 was susceptible to trimethoprim. Epidemiological typing by antibiogram-resistogram (AR) typing, biotyping and by chromosomal DNA restriction fragment length polymorphism analysis using SmaI digestion followed by pulsed field gel electrophoresis (PFGE), confirmed these two major clusters. PFGE analysis showed that most isolates from non-equine animals were indistinguishable from each other and from the isolates from personnel caring for these animals. MRSA was isolated from eight horses which attended six different veterinary practices before referral to an equine veterinary hospital. Isolates from the eight horses and from their attendant personnel had PFGE patterns that were indistinguishable and were unlike the patterns obtained from the other isolates. Comparison of PFGE patterns of isolates from veterinary sources with patterns from MRSA recovered in human hospitals showed that the most frequently occurring pattern of MRSA from non
YU Yi-yun; WANG Hong; ZHANG Shu-wen; WANG Bao-en
Background The infection rate of methicillin-resistant Staphylococcus aureus (MRSA) is increasing yearly due to the overprescription of antibiotics. Traditional Chinese compound medicines are less inclined to induce bacterial resistance in the clinical setting because of their multi-acting mechanisms. However, most current research is limited to bacteriostasis in vitro using single extracts or formulations. Plasma pharmacology is an in vitro method, using what is called "medicine serum". The aim of this study was to investigate whether the medicine serum of compound Qingre granules (QRKL) alone or in combination with antibiotics may treat MRSA infection in the clinic.Methods An animal model of MRSA resistance was created by injecting rabbits with the standard strain of MRSA ATCC43300. Infected rabbits were treated with QRKL by intragastric administration. Sixty minutes after the last intragastric administration, serum was obtained from the rabbits by heart puncture to obtain what is termed "medicine serum". The minimum inhibitory concentration (MIC) of QRKL, medicine serum alone, or serum combined with antibiotics was assessed by agar dilution. Results were compared with the growth of sixteen isolates of MRSA. Results The MIC of QRKL to the standard strain ATCC43300 was 10.00 mg/ml. The MIC_(90)of vancomycin was 1.00 ug/ml, which, when combined with QRKL, dropped to 0.50 μg/ml. The MIC_(90) of cefuroxime alone was 512.00 μg/ml- This level also decreased to 256.00 μ g/ml when combined with QRKL. The addition of QRKL thus significantly reduced the MIC of both cefuroxime and vancomycin compared with antibiotics alone (P <0.01). The MIC90 of vancomycin with medicine serum decreased to 0.50 μ g/ml, and the MIC of vancomycin with medicine serum also descended compared with using vancomycin alone (P<0.01).Conclusions The growth of MRSA can be inhibited by QRKL or medicine serum of QRKL in vitro. The addition of QRKL results in increased sensitivity of MRSA to
Medina, G; Egea, A L; Otth, C; Otth, L; Fernández, H; Bocco, J L; Wilson, M; Sola, C
Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen of public health importance. In Chile, the Cordobes/Chilean clone was the predominant healthcare-associated MRSA (HA-MRSA) clone in 1998. Since then, the molecular epidemiological surveillance of MRSA has not been performed in Southern Chile. We aimed to investigate the molecular epidemiology of HA-MRSA infections in Southern Chile to identify the MRSA clones involved, and their evolutionary relationships with epidemic international MRSA lineages. A total of 303 single inpatient isolates of S. aureus were collected in the Valdivia County Hospital (2007-2008), revealing 33% (100 MRSA/303) prevalence for HA-MRSA infections. The SCCmec types I and IV were identified in 97% and 3% of HA-MRSA, respectively. All isolates lacked the pvl genes. A random sample (n = 29) of all MRSA was studied by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), SCCmec subtyping, agr and spa typing, and virulence genes profiling. PFGE analysis revealed the predominance (89%, 26/29) of pulsotype A and three additional pulsotypes, designated H1, I33, and G1. Pulsotype A (ST5-SCCmecI-spa-t149) is clonally related to the Cordobes/Chilean clone. Pulsotype H1 (ST5-SCCmecIVNT-spa-t002) is genetically related to the Pediatric clone (ST5-SCCmecIV). Pulsotype I33 (ST5-SCCmecIVc-spa-t002) is clonally related by PFGE to the community-associated MRSA (CA-MRSA) clone spread in Argentina, I-ST5-IVa-PVL(+). The G1 pulsotype (ST8-SCCmecIVc-spa-t024) is clonally related to the epidemic USA300 CA-MRSA. Here, we demonstrate the stability of the Cordobes/Chilean clone over time as the major HA-MRSA clone in Southern Chile. The identification of two CA-MRSA clones might suggest that these clones have entered into the healthcare setting from the community. These results emphasize the importance of the local surveillance of MRSA infections in the community and hospital settings.
Argudín, M Angeles; Lauzat, Birgit; Kraushaar, Britta; Alba, Patricia; Agerso, Yvonne; Cavaco, Lina; Butaye, Patrick; Porrero, M Concepción; Battisti, Antonio; Tenhagen, Bernd-Alois; Fetsch, Alexandra; Guerra, Beatriz
Livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has emerged in animal production worldwide. Most LA-MRSA in Europe belong to the clonal complex (CC) 398. The reason for the LA-MRSA emergence is not fully understood. Besides antimicrobial agents used for therapy, other substances with antimicrobial activity applied in animal feed, including metal-containing compounds might contribute to their selection. Some of these genes have been found in various novel SCCmec cassettes. The aim of this study was to assess the occurrence of metal-resistance genes among a LA-S. aureus collection [n=554, including 542 MRSA and 12 methicillin-susceptible S. aureus (MSSA)] isolated from livestock and food thereof. Most LA-MRSA isolates (76%) carried at least one metal-resistance gene. Among the LA-MRSA CC398 isolates (n=456), 4.8%, 0.2%, 24.3% and 71.5% were positive for arsA (arsenic compounds), cadD (cadmium), copB (copper) and czrC (zinc/cadmium) resistance genes, respectively. In contrast, among the LA-MRSA non-CC398 isolates (n=86), 1.2%, 18.6% and 16.3% were positive for the cadD, copB and czrC genes, respectively, and none were positive for arsA. Of the LA-MRSA CC398 isolates, 72% carried one metal-resistance gene, and the remaining harboured two or more in different combinations. Differences between LA-MRSA CC398 and non-CC398 were statistically significant for arsA and czrC. The czrC gene was almost exclusively found (98%) in the presence of SCCmec V in both CC398 and non-CC398 LA-MRSA isolates from different sources. Regarding the LA-MSSA isolates (n=12), some (n=4) were also positive for metal-resistance genes. This study shows that genes potentially conferring metal-resistance are frequently present in LA-MRSA.
Full Text Available BACKGROUND: Staphylococcus aureus causes a variety of severe infections such as bacteremia and sepsis. At present, 60-80% of S. aureus isolates from Taiwan are methicillin resistant (MRSA. It has been shown that certain MRSA clones circulate worldwide. The goals of this study were to identify MRSA clones in Taiwan and to correlate the molecular types of isolates with their phenotypes. METHODS: A total of 157 MRSA isolates from bacteremic patients were collected from nine medical centers. They were typed based on polymorphisms in agr, SCCmec, MLST, spa, and dru. Phenotypes characterized included Panton-Valentine leucocidin (pvl, inducible macrolide-lincosamide-streptogramin B resistance (MLSBi, vancomycin (VA and daptomycin (DAP minimal inhibitory concentrations (MIC, and superantigenic toxin gene profiles. Difference between two consecutive samples was determined by Mann-Whitney-U test, and difference between two categorical variables was determined by Fisher's exact test. RESULTS: Four major MRSA clone complexes CC1, CC5, CC8, and CC59 were found, including 4 CC1, 9 CC5, 111 CC8, and 28 CC59 isolates. These clones had the following molecular types: CC1: SCCmecIV and ST573; CC5: SCCmecII and ST5; CC8: SCCmecIII, ST239, and ST241, and CC59: SCCmecIV, SCCmecV(T, ST59, and ST338. The toxin gene profiles of these clones were CC1: sec-seg-(sei-sell-selm-(seln-selo; CC5: sec-seg-sei-sell-selm-(seln-selp-tst1; CC8: sea-selk-selq, and CC59: seb-selk-selq. Most isolates with SCCmecV(T, ST59, spat437, and dru11 types were pvl(+ (13 isolates, while multidrug resistance (≥4 antimicrobials were associated with SCCmecIII, ST239, spa t037, agrI, and dru14 (119 isolates (p<0.001. One hundred and twenty four isolates with the following molecular types had higher VA MIC: SCCmecII and SCCmecIII; ST5, ST239, and ST241; spa t002, t037, and t421; dru4, dru10, dru12, dru13, and dru14 (p<0.05. No particular molecular types were found to be associated with MLSBi
Nemeghaire, Stéphanie; Argudín, M Angeles; Haesebrouck, Freddy; Butaye, Patrick
Staphylococcus aureus is a common bacterium usually found on skin and mucous membranes of warm blooded animals. Resistance in S. aureus has been increasingly reported though depending on the clonal lineage. Indeed, while hospital acquired (HA)-methicillin resistant S. aureus (MRSA) are typically multi-resistant, community associated (CA)-MRSA are by large more susceptible to many antibiotics. Although S. aureus isolated from animals are often susceptible to most antibiotics, multi-resistant livestock associated (LA)-MRSA have been recovered from bovine mastitis.In this study, we investigated the prevalence and types of MRSA present in the nose of healthy bovines of different age groups and rearing practices. Since no validated methods for MRSA isolation from nasal swabs were available, we compared two isolation methods. Molecular characterization was performed by means of spa-typing, MLST, SCCmec typing and microarray analysis for the detection of antimicrobial resistance and virulence genes. MRSA between herd prevalence in bovines was estimated at 19.8%. There was a marked difference between rearing practices with 9.9%, 10.2% and 46.1% of the dairy, beef and veal calve farms respectively being MRSA positive. No significant difference was observed between both isolation methods tested. Most isolates were ST398 spa type t011 or closely related spa types. Few ST239 spa type t037 and t388 and ST8 spa type t121 were also found. SCCmec types carried by these strains were mainly type IV(2B), IV(2B&5) and type V. Type III and non-typeable SCCmec were recovered to a lesser extent. All isolates were multi-resistant to at least two antimicrobials in addition to the expected cefoxitin and penicillin resistance, with an average of resistance to 9.5 different antimicrobials. Isolates selected for microarray analysis carried a broad range of antimicrobial resistance and virulence genes. MRSA were mainly present in veal farms, compared to the lower prevalence in dairy or beef
Gupta, Priyanka; Patel, Dinesh Kumar; Gupta, Vivek Kumar; Pal, Anirban; Tandon, Sudeep; Darokar, M P
Staphylococcus aureus (SA), is a major human pathogen causing wide range of clinical infections, which has been further complicated by drug resistance like methicillin resistant S. aureus (MRSA), vancomycin intermediate S. aureus (VISA)/vancomycin resistant S. aureus (VRSA), etc. The present study was aimed at determining anti-staphylococcal potential of citral against drug resistant clinical isolates alone and in combination with antibiotics. To assess the potential of citral in combination with norfloxacin in treating drug resistant infections of SA. In the present study, synergistic interaction of citral and norfloxacin against drug resistant SA strains was evaluated. Further the efficacy and possible mechanism of action of the combination was also evaluated using in vitro and in vivo assays. The anti-staphylococcal activity of each of the monoterpene and the antibiotic was determined in terms of MIC and the effective concentration of both compounds in combination was obtained by checkerboard assay. In vivo efficacy and oral acute toxicity was evaluated in Swiss albino mice model. To understand the mechanism of action, time-kill curve, bacteriolysis, leakage, membrane depolarization, salt tolerance and ethidium bromide efflux assays were performed. Citral was found effective against clinical isolates of SA with MIC values ranging from 75 to 150 µg ml(-1) exhibiting bacteriostatic activity. Citral interacted synergistically, reducing MIC of norfloxacin up to 32-folds with FICI ≤ 0.50. Citral did not affect cell wall, but could damage cell membrane, inhibit efflux pump and affect the membrane potential. Citral could reduce the staphylococcal load of spleen and liver tissues in a dose-dependent manner which was further reduced when used in combination with norfloxacin. Citral did not exhibit any mortality or morbidity up to 500 mg kg(-1) body weight and found to prolong the post-antibiotic effect of norfloxacin. Based on these observations, citral could
Verstappen, Koen M; Tulinski, Pawel; Duim, Birgitta; Fluit, Ad C; Carney, Jennifer; van Nes, Arie; Wagenaar, Jaap A
Methicillin-resistant Staphylococcus aureus (MRSA) is an important colonizer in animals and an opportunistic pathogen in humans. In humans, MRSA can cause infections that might be difficult to treat because of antimicrobial resistance. The use of bacteriophages has been suggested as a potential approach for the control of MRSA colonization to minimize the-often occupational-exposure of humans. The aim of this study was to assess the efficacy of bacteriophage treatment on porcine nasal colonization with MRSA in vitro, in vivo, and ex vivo. The effectiveness of a bacteriophage combination of phage K*710 and P68 was assessed in vitro by incubating them with MRSA V0608892/1 (ST398) measuring the OD600 hourly. To study the in vivo effect, bacteriophages were administered in a gel developed for human application, which contain 109 plaque-forming units (pfu)/mL (K and P68 in a 19.25:1 ratio) for 5 days to piglets (N = 8) that were experimentally colonized with the MRSA strain. Eight piglets experimentally colonized were used as a negative control. The MRSA strain was also used to colonize porcine nasal mucosa explants and bacteriophages were applied to assess the ex vivo efficacy of treatment. Bacteriophages were effective in vitro. In vivo, sixteen piglets were colonized with MRSA but the number of CFU recovered after the application of the bacteriophages in 8 piglets was not reduced compared to the control animals (approx. 105 CFU/swab). In the ex vivo model, 108 CFU were used to establish colonization with MRSA; a reduction of colonization was not observed after application of bacteriophages. However, application of mupirocin both in vivo and ex vivo resulted in a near eradication of MRSA. i) The MRSA strain was killed in the presence of the bacteriophages phage K*710 and P68 in vitro. ii) Bacteriophages did not reduce porcine nasal colonization in vivo or ex vivo. Physiological in vivo and ex vivo conditions may explain these observations. Efficacy in the ex vivo
Uddin, Reaz; Saeed, Kiran; Khan, Waqasuddin; Azam, Syed Sikander; Wadood, Abdul
Multiple Drug Resistant (MDR) bacteria are no more inhibited by the front line antibiotics due to extreme resistance. Methicillin Resistant Staphylococcus aureus (MRSA) is one of the MDR pathogens notorious for its widespread infection around the world. The high resistance acquired by MRSA needs a serious concern and efforts should be carried out for the discovery of better therapeutics. With this aim, we designed a comparison of the metabolic pathways of the pathogen, MRSA strain 252 (MRSA252) with the human host (i.e., Homo sapiens) by using well-established in silico methods. We identified several metabolic pathways unique to MRSA (i.e., absent in the human host). Furthermore, a subtractive genomics analysis approach was applied for retrieval of proteins only from the unique metabolic pathways. Subsequently, proteins of unique MRSA pathways were compared with the host proteins. As a result, we have shortlisted few unique and essential proteins that could act as drug targets against MRSA. We further assessed the druggability potential of the shortlisted targets by comparing them with the DrugBank Database (DBD). The identified drug targets could be useful for an effective drug discovery phase. We also searched the sequences of unique as well as essential enzymes from MRSA in Protein Data Bank (PDB). We shortlisted at least 12 enzymes for which there was no corresponding deposition in PDB, reflecting that their crystal structures are yet to be solved! We selected Glutamate synthase out of those 12 enzymes owing to its participation in significant metabolic pathways of the pathogen e.g., Alanine, Aspartate, Glutamate and Nitrogen metabolism and its evident suitability as drug target among other MDR bacteria e.g., Mycobacteria. Due to the unavailability of any crystal structure of Glutamate synthase in PDB, we generated the 3D structure by homology modeling. The modeled structure was validated by multiple analysis tools. The active site of Glutamate synthase was
Vidaillac, Céline; Rybak, Michael J
Ceftobiprole medocaril is the first member of a new series of advanced cephalosporins with activity against methicillin-resistant Staphylococcus aureus (MRSA). The drug received an approvable letter from the United States Food and Drug Administration (FDA) in March 2008 and from Health Canada in June 2008 for the treatment of complicated skin and skin structure infections including diabetic foot infections. Ceftobiprole exerts its antibacterial activity by inhibiting the penicillin-binding proteins (PBPs) involved in cell wall synthesis. It has an established stability against hydrolysis by many gram-positive beta-lactamases and a higher affinity for various PBPs (such as PBP2a of MRSA or PBP2x of Streptococcus pneumoniae), which leads to a wider spectrum of activity compared with older beta-lactams. Ceftobiprole activity does not cover extended-spectrum beta-lactamase-producing Enterobacteriaceae and some other pathogens, including Enterococcus faecium or Acinetobacter baumanii. Generally well tolerated, with nausea and taste disturbance being the most common adverse events, ceftobiprole appeared noninferior to empiric therapy in several clinical trials. Ceftobiprole is available only for intravenous administration; recommended dosage regimens have not been approved by the FDA as of this writing. However, based on the Canadian package insert, expected dosage recommendations are 500 mg as a 1-hour intravenous infusion every 12 hours for the treatment of complicated skin and skin structure infections caused by certain gram-positive pathogens, and 500 mg as a 2-hour infusion every 8 hours when susceptible gram-negative or both gram-positive and susceptible gram-negative pathogens are involved. Dosage adjustments are indicated for patients with moderate or severe renal impairment, and dosage recommendations are expected to be 500 or 250 mg, respectively, as a 2-hour infusion every 12 hours. Several precautions regarding hypersensitivity and drug incompatibility are
El-Adawy, Hosny; Ahmed, Marwa; Hotzel, Helmut; Monecke, Stefan; Schulz, Jochen; Hartung, Joerg; Ehricht, Ralf; Neubauer, Heinrich; Hafez, Hafez M.
Methicillin-resistant Staphylococcus aureus (MRSA) is a major human health problem and recently, domestic animals are described as carriers and possible reservoirs. Twenty seven S. aureus isolates from five turkey farms (n = 18) and two broiler farms (n = 9) were obtained by culturing of choana and skin swabs from apparently healthy birds, identified by Taqman-based real-time duplex nuc-mecA-PCR and characterized by spa typing as well as by a DNA microarray based assay which covered, amongst others, a considerable number of antibiotic resistance genes, species controls, and virulence markers. The antimicrobial susceptibility profiles were tested by agar diffusion assays and genotypically confirmed by the microarray. Five different spa types (3 in turkeys and 2 in broilers) were detected. The majority of MRSA isolates (24/27) belonged to clonal complex 398-MRSA-V. The most frequently occurring spa types were accordingly t011, t034, and t899. A single CC5-MRSA-III isolated from turkey and CC398-MRSA with an unidentified/truncated SCCmec element in turkey and broiler were additionally detected. The phenotypic antimicrobial resistance profiles of S. aureus isolated from both turkeys and broilers against 14 different antimicrobials showed that all isolates were resistant to ampicillin, cefoxitin, oxacillin, doxycycline, and tetracycline. Moreover, all S. aureus isolated from broilers were resistant to erythromycin and azithromycin. All isolates were susceptible to gentamicin, chloramphenicol, sulphonamides, and fusidic acid. The resistance rate against ciprofloxacin was 55.6% in broiler isolates and 42.1% in turkey isolates. All tetracycline resistant isolates possessed genes tetK/M. All erythromycin-resistant broiler isolates carried ermA. Only one broiler isolate (11.1%) carried genes ermA, ermB, and ermC, while 55.6% of turkey isolates possessed ermA and ermB genes. Neither PVL genes (lukF/S-PV), animal-associated leukocidin (lukM and luk-P83) nor the gene encoding
Carson, Kerry C; Bartlett, Jessica G; Tan, Trina-Jean; Riley, Thomas V
The soluble copper silicate (CS) MIC of 100 strains of methicillin-resistant Staphylococcus aureus and 100 strains of methicillin-susceptible S. aureus (MSSA) was 175 mg Cu/liter. Bactericidal and postantibiotic effects (> or =1 h) were seen at 2x MIC and 4x MIC. The frequency of mutation was <10(-9), and serial passage could not extend growth beyond 1.6x MIC.
Li, Yanmeng; Zhao, Ruike; Zhang, Xianfeng; Han, Qingzhen; Qian, Xuefeng; Gu, Guohao; Shi, Jinfang; Xu, Jie
Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen that causes a variety of infections. MRSA has evolved resistance to multiple antibiotics. Genetic background and virulence differs in different geographic regions. The present study was aimed to investigate the prevalence of enterotoxin genes and spa genotypes of hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) isolated from a tertiary care hospital of Jiangsu province, China. HA-MRSA isolates from August 2013 to April 2014 at a tertiary care hospital of China were collected. We investigated antimicrobial pattern, spa types, SCCmec types and the presence of 14 virulence genes. Eighty HA-MRSA isolates were collected. Results from SCCmec typing revealed that 73.8% were type II; 13.8% were type III; 12.5% were type V. There were 19 different spa types. Spa type t2460 was the most common (35.0%), followed by t002 (11.3%). CC5 was the predominant MLST CCs type (50%). The most frequent toxin genes were sea, seb, sed, sel, sen and seo (100.0%). None of the investigated isolates carried the sec or tst. Genotypic and virulence evaluation of the isolated HA-MRSA revealed that the isolates with CC5 and SCCmec II were the predominant type and highly homological. The virulence profiles mainly existed in the genes of sea, seb, sed, sel, sen, seo and ser. The prevalence of t2460 was an outbreak and the predominant spa type.
Full Text Available CONTEXT: Staphylococcal scalded skin syndrome is an exfoliative skin disease. Reports of this syndrome in newborns caused by methicillin-resistant Staphylococcus aureus are rare but, when present, rapid diagnosis and treatment is required in order to decrease morbidity and mortality. CASE REPORT: A premature newly born girl weighing 1,520 g, born with a gestational age of 29 weeks and 4 days, developed staphylococcal scalded skin syndrome on the fifth day of life. Cultures on blood samples collected on the first and fourth days were negative, but Pseudomonas aeruginosa and Enterococcus sp. (vancomycin-sensitive developed in blood cultures performed on the day of death (seventh day, and Pseudomonas aeruginosa and Serratia marcescens were identified in cultures on nasopharyngeal, buttock and abdominal secretions. In addition to these two Gram-negative bacilli, methicillin-resistant Staphylococcus aureus was isolated in a culture on the umbilical stump (seventh day. The diagnosis of staphylococcal scalded skin syndrome was based on clinical criteria.
Gómez-Sanz, E; Simón, C; Ortega, C; Gómez, P; Lozano, C; Zarazaga, M; Torres, C
Eight coagulase-positive staphylococci from equines with different pathologies obtained between 2005 and 2011 were investigated. Isolates were characterized by different molecular techniques (spa-, agr-, MLST), and clonal relatedness of strains was investigated by ApaI and SmaI PFGE. Anti-microbial resistance and virulence profiles were determined. Six isolates were identified as Staphylococcus aureus, and two as Staphylococcus pseudintermedius. Of these, four isolates were methicillin-resistant S. aureus (MRSA) ST398 and one S. pseudintermedius was mecA positive and typed as ST68. One MRSA ST398 strain was isolated in 2005 and might be one of the earliest MRSA ST398 descriptions in Spain. All 5 mecA-positive strains were multidrug resistant and were isolated from hospitalized equines. Three MRSA ST398 strains carried the recently described transposon Tn559 within the chromosomal radC gene. The mecA-positive S. pseudintermedius ST68 strain was also multidrug resistant and harboured the erm(B)-Tn5405-like element. This ST68 strain presented a clear susceptible phenotype to oxacillin and cefoxitin regardless of the presence of an integral and conserved mecA gene and mecA promoter, which enhances the need for testing the presence of this gene in routine analysis to avoid treatment failures. These data reflect the extended anti-microbial resistance gene acquisition capacities of both bacterial species and evidence their pathogenic properties. The first detection of MRSA ST398 and S. pseudintermedius ST68 in horses in Spain is reported.
Veena Kumari H
Full Text Available Septic cavernous sinus thrombosis (CST is an uncommon clinical syndrome. Although Staphylococcus aureus (S aureus is the most common bacterial pathogen causing CST, it is infrequent as a cause of meningitis. We report the first case of CST and meningitis from Bengaluru, Karnataka, caused by community-acquired epidemic methicillin resistant Staphylococcus aureus-15 (EMRSA-15, in a previously healthy individual without known risk factors; the patient recovered following treatment with vancomycin. The isolate was genotyped as belonging to staphylococcal cassette chromosome mec type IV and sequence type 22 and carried the panton-valentine leucocidin gene. It is the first Indian EMRSA-15 disease isolate from a case of meningitis. EMRSA-15 has been a major problem in hospitals in UK and it is a cause for great concern in Indian hospitals too.
Casero, Carina; Estévez-Braun, Ana; Ravelo, Angel G; Demo, Mirta; Méndez-Álvarez, Sebastián; Machín, Félix
Currently, there is a pressing need for novel antibacterial agents against drug-resistant bacteria, especially those which have been common in our communities and hospitals, such as methicillin-resistant Staphylococcus aureus (MRSA). The South American plant Achyrocline satureioides ("Marcela") has been widely used in traditional medicine for a number of diseases, including infections. Several crude extracts from this plant have shown good antimicrobial activities in vitro. In the search for the active principle(s) that confers these antimicrobial activities, we have processed the dichloromethane extract from the aerial parts of the plant. One of the isolated compounds showed extraordinary antibacterial activities against a set of clinically relevant Gram-positive strains that widely differ in their antibiogram profiles. This compound was identified as achyrofuran on the basis of its spectroscopic and physical data. We determined the MIC to be around 0.1 μM (0.07 μg/ml) for the reference methicillin-resistant and vancomycin-intermediate S. aureus strain NRS402. Moreover, nanomolar concentrations of achyrofuran killed 10(6) bacteria within 12 h. Based on the presence of the 2,2'-biphenol core, we further studied whether achyrofuran killed bacteria through a mechanism of action similar to that reported for the naturally occurring antibiotic MC21-A. Indeed, we found that achyrofuran was not bacteriolytic by itself although it greatly compromised membrane impermeability as determined by increased SYTOX Green uptake.
Moodley, Arshnee; Damborg, Peter; Nielsen, Søren Saxmose
Staphylococcus pseudintermedius is a commensal and a common opportunistic pathogen causing mainly infections of the integumentary system in dogs. The recent emergence of multidrug-resistant S. pseudintermedius isolates, in particular methicillin-resistant strains (MRSP) is a threat to small animal health and highlights the need for antimicrobial resistance surveillance to detect trends and potentially perform timeous interventions. We systematically reviewed 202 published articles to investigate temporal changes in antimicrobial resistance in clinical and commensal S. pseudintermedius isolated from dogs in 27 countries between 1980 and 2013. Resistance to the most common antimicrobials tested for in published studies and important for the treatment of staphylococcal infections in dogs were assessed separately for methicillin resistant (MRSP) and methicillin susceptible (MSSP) isolates. Stratified by MSSP and MRSP, no significant increases in antimicrobial resistance were observed over time, except for the penicillinase-labile penicillins (penicillin and ampicillin) among MSSP. However, in recent years, a few studies have reported higher-level of resistance to amikacin, gentamicin and enrofloxacin amongst MSSP. The review highlights inconsistencies between studies as a result of several factors, for example the use of different antimicrobial susceptibility testing methods and interpretation criteria. We recommend that data on susceptibility in important companion animal pathogens are collected and presented in a more harmonized way to allow more precise comparison of susceptibility patterns between studies. One way to accomplish this would be through systematic surveillance either at the country-level or at a larger scale across countries e.g. EU level.
Figueiredo, Agnes Marie Sá; Ferreira, Fabienne Antunes
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important bacterial pathogens based on its incidence and the severity of its associated infections. In addition, severe MRSA infections can occur in hospitalised patients or healthy individuals from the community. Studies have shown the infiltration of MRSA isolates of community origin into hospitals and variants of hospital-associated MRSA have caused infections in the community. These rapid epidemiological changes represent a challenge for the molecular characterisation of such bacteria as a hospital or community-acquired pathogen. To efficiently control the spread of MRSA, it is important to promptly detect the mecA gene, which is the determinant of methicillin resistance, using a polymerase chain reaction-based test or other rapidly and accurate methods that detect the mecA product penicillin-binding protein (PBP)2a or PBP2’. The recent emergence of MRSA isolates that harbour a mecA allotype, i.e., the mecC gene, infecting animals and humans has raised an additional and significant issue regarding MRSA laboratory detection. Antimicrobial drugs for MRSA therapy are becoming depleted and vancomycin is still the main choice in many cases. In this review, we present an overview of MRSA infections in community and healthcare settings with focus on recent changes in the global epidemiology, with special reference to the MRSA picture in Brazil. PMID:24789555
Huang, Y; Oie, S; Kamiya, A
Five subjects participated in a study of optimal conditions for removing methicillin-resistant Staphylococcus aureus from contaminated fingertips. Fingertips were contaminated experimentally and cleaned by various methods. Bacterial removal was measured as percentage and is given as mean +/- standard error of the mean. Rinsing the fingertips with tap water for 20 seconds and drying them with paper towels removed 95.2% +/- 1.6% of the contamination. Application of hand-cleansing agents to fingertips for 20 seconds, followed by a 20-second tap-water rinse and towel drying, removed bacteria as follows: povidone-iodine detergent, 99.2% +/- 0.4%; chlorhexidine detergent, 97.2% +/- 0.8%; and liquid soap, 96.1% +/- 1.1%. In a modification of the method, 80% ethyl alcohol applied to the fingertips for 20 seconds, followed by air drying for 40 seconds, removed 99.1% +/- 0.8% of the bacteria. Statistical analyses indicated that povidone-iodine and 80% ethyl alcohol were more effective than the other agents. Rinsing contaminated fingertips with tap water and towel drying them is sufficient to reduce contamination with methicillin-resistant S. aureus by 95%. Washing with povidone-iodine or 80% ethyl alcohol further reduces contamination by an additional 99%.
Necula, Bogdan S; Fratila-Apachitei, Lidy E; Zaat, Sebastian A J; Apachitei, Iulian; Duszczyk, Jurek
The aim of this study was the synthesis of a porous TiO(2)-Ag composite coating and assessment of its in vitro bactericidal activity against methicillin-resistant Staphylococcus aureus. The coating was produced by plasma electrolytic oxidation of Ti-6Al-7Nb medical alloy in a calcium acetate/calcium glycerophosphate electrolyte bearing Ag nanoparticles. Following oxidation, the surface of the titanium substrate was converted into the corresponding oxide (TiO(2)) bearing Ca and P species from the electrolyte. In addition, Ag was detected associated with particles present in the oxide layers. The coatings revealed a porous interconnected structure with pores up to 3 microm in size, a threefold increase in roughness and improved wettability relative to the non-oxidized specimens. The composite TiO(2)-Ag coating showed complete killing of methicillin-resistant S. aureus within 24h in all culture conditions, whereas a 1000-fold increase in bacterial numbers was recorded with the ground titanium specimens and the samples oxidized in the absence of Ag nanoparticles.
Hill-Cawthorne, Grant A.
Clinical laboratories are increasingly using molecular tests for methicillin-resistant Staphylococcus aureus (MRSA) screening. However, primers have to be targeted to a variable chromosomal region, the staphylococcal cassette chromosome mec (SCCmec). We initially screened 726 MRSA isolates from a single UK hospital trust by recombinase polymerase amplification (RPA), a novel, isothermal alternative to PCR. Undetected isolates were further characterised using multilocus sequence, spa typing and whole genome sequencing. 96% of our tested phenotypically MRSA isolates contained one of the six orfX-SCCmec junctions our RPA test and commercially available molecular tests target. However 30 isolates could not be detected. Sequencing of 24 of these isolates demonstrated recombinations within the SCCmec element with novel insertions that interfered with the RPA, preventing identification as MRSA. This result suggests that clinical laboratories cannot rely solely upon molecular assays to reliably detect all methicillin-resistance. The presence of significant recombinations in the SCCmec element, where the majority of assays target their primers, suggests that there will continue to be isolates that escape identification. We caution that dependence on amplification-based molecular assays will continue to result in failure to diagnose a small proportion (?4%) of MRSA isolates, unless the true level of SCCmec natural diversity is determined by whole genome sequencing of a large collection of MRSA isolates. © 2014 Hill-Cawthorne et al.
Grant A Hill-Cawthorne
Full Text Available Clinical laboratories are increasingly using molecular tests for methicillin-resistant Staphylococcus aureus (MRSA screening. However, primers have to be targeted to a variable chromosomal region, the staphylococcal cassette chromosome mec (SCCmec. We initially screened 726 MRSA isolates from a single UK hospital trust by recombinase polymerase amplification (RPA, a novel, isothermal alternative to PCR. Undetected isolates were further characterised using multilocus sequence, spa typing and whole genome sequencing. 96% of our tested phenotypically MRSA isolates contained one of the six orfX-SCCmec junctions our RPA test and commercially available molecular tests target. However 30 isolates could not be detected. Sequencing of 24 of these isolates demonstrated recombinations within the SCCmec element with novel insertions that interfered with the RPA, preventing identification as MRSA. This result suggests that clinical laboratories cannot rely solely upon molecular assays to reliably detect all methicillin-resistance. The presence of significant recombinations in the SCCmec element, where the majority of assays target their primers, suggests that there will continue to be isolates that escape identification. We caution that dependence on amplification-based molecular assays will continue to result in failure to diagnose a small proportion (∼4% of MRSA isolates, unless the true level of SCCmec natural diversity is determined by whole genome sequencing of a large collection of MRSA isolates.
Agnes Marie Sá Figueiredo
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA is one of the most important bacterial pathogens based on its incidence and the severity of its associated infections. In addition, severe MRSA infections can occur in hospitalised patients or healthy individuals from the community. Studies have shown the infiltration of MRSA isolates of community origin into hospitals and variants of hospital-associated MRSA have caused infections in the community. These rapid epidemiological changes represent a challenge for the molecular characterisation of such bacteria as a hospital or community-acquired pathogen. To efficiently control the spread of MRSA, it is important to promptly detect the mecA gene, which is the determinant of methicillin resistance, using a polymerase chain reaction-based test or other rapidly and accurate methods that detect the mecA product penicillin-binding protein (PBP2a or PBP2’. The recent emergence of MRSA isolates that harbour a mecA allotype, i.e., the mecC gene, infecting animals and humans has raised an additional and significant issue regarding MRSA laboratory detection. Antimicrobial drugs for MRSA therapy are becoming depleted and vancomycin is still the main choice in many cases. In this review, we present an overview of MRSA infections in community and healthcare settings with focus on recent changes in the global epidemiology, with special reference to the MRSA picture in Brazil.
Saddiq, Amna Ali; Mohamed, Azza Mostafa
The aim of this study was to explore the protective impact of aqueous extract of Saudi red propolis against rat lung damage induced by the pathogenic bacteria namely methicillin resistant Staphylococcus aureus (MRSA) ATCC 6538 strain. Infected rats were received a single intraperitoneal (i.p.) injection of bacterial suspension at a dose of 1 X 10(6) CFU / 100g body weight. Results showed that oral administration of an aqueous extract of propolis (50mg/100g body weight) daily for two weeks to infected rats simultaneously with bacterial infection, effectively ameliorated the alteration of oxidative stress biomarker, malondialdehyde (MDA), as well as the antioxidant markers, glutathione peroxidase (GPx) and superoxide dismutase (SOD), in lungs of infected rats compared with infected untreated ones. Also, the used propolis extract successfully modulated the alterations in proinflammatory mediators, tumor necrosis factor-α (TNF- α) and vascular endothelial growth factor (VEGF) in serum. In addition, the propolis extract successfully modulated the oxidative DNA damage and the apoptosis biomarker, caspase 3, in lungs of S aureus infected rats compared with infected untreated animals. The biochemical results were supported by histo-pathological observation of lung tissues. In conclusion, the beneficial prophylactic role of the aqueous extract of Saudi red propolis against lung damage induced by methicillin resistant S aureus may be related to the antioxidant, anti-inflammatory, immunomodulatory and antiapoptosis of its active constituents.
Full Text Available Abdulhakeem O Althaqafi,1 Madonna J Matar,2 Rima Moghnieh,3 Adel F Alothman,4 Thamer H Alenazi,5 Fayssal Farahat,1 Shelby Corman,6 Caitlyn T Solem,6 Nirvana Raghubir,7 Cynthia Macahilig,8 Seema Haider,9 Jennifer M Stephens6 1Department of Infection Prevention and Control, King Abdullah International Medical Research Center, King Saud bin AbdulAziz University for Health Sciences, Jeddah, Kingdom of Saudi Arabia; 2Department of Infectious Disease, Notre Dame de Secours University Hospital, Byblos, 3Makassed General Hospital, Beirut, Lebanese Republic; 4Department of Medicine, King Abdulaziz Medical City, Central Region, Ministry of National Guard Health Affairs, 5Infection Prevention & Control Department, King Abdulaziz Medical City-Riyadh (KAMC, Kingdom of Saudi Arabia; 6Real World Evidence: Data Analytics Center of Excellence, Pharmerit International, Bethesda, MD, 7Medical Affairs, Pfizer, New York, NY, 8Medical Data Analytics, Parsippany, NJ, 9Outcomes & Evidence, Global Health and Value, Pfizer, Groton, CT, USA Objectives: The objective of this study is to describe the real-world treatment patterns and burden of suspected or confirmed methicillin-resistant Staphylococcus aureus (MRSA pneumonia in Saudi Arabia and Lebanon. Methods: A retrospective chart review study evaluated 2011–2012 data from hospitals in Saudi Arabia and Lebanon. Patients were included if they had been discharged with a diagnosis of MRSA pneumonia, which was culture proven or suspected based on clinical criteria. Hospital data were abstracted for a random sample of patients to capture demographics (eg, age and comorbidities, treatment patterns (eg, timing and use of antimicrobials, hospital resource utilization (eg, length of stay, and clinical outcomes (eg, clinical status at discharge and mortality. Descriptive results were reported using frequencies or proportions for categorical variables and mean and standard deviation for continuous variables. Results: Chart
Yang, Xiaojuan; Zhang, Jumei; Yu, Shubo; Wu, Qingping; Guo, Weipeng; Huang, Jiahui; Cai, Shuzhen
Staphylococcus aureus, particularly methicillin-resistant S.aureus (MRSA), is a life-threatening pathogen in humans, and its presence in food is a public health concern. MRSA has been identified in foods in China, but little information is available regarding MRSA in ready-to-eat (RTE) foods. We aimed to investigate the prevalence of S. aureus and MRSA in Chinese retail RTE foods. All isolated S. aureus were tested for antimicrobial susceptibility, and MRSA isolates were further characterized by multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) typing. Of the 550 RTE foods collected from 2011 to 2014, 69 (12.5%) were positive for S. aureus. Contamination levels were mostly in the range of 0.3-10 most probable number (MPN)/g, with five samples exceeding 10 MPN/g. Of the 69 S. aureus isolates, seven were identified as MRSA by cefoxitin disc diffusion test. Six isolates were mecA-positive, while no mecC-positive isolates were identified. In total, 75.8% (47/62) of the methicillin-susceptible S. aureus isolates and all of the MRSA isolates were resistant to three or more antibiotics. Amongst the MRSA isolates, four were identified as community-acquired strains (ST59-MRSA-IVa (n = 2), ST338-MRSA-V, ST1-MRSA-V), while one was a livestock-associated strain (ST9, harboring an unreported SCCmec type 2C2). One novel sequence type was identified (ST3239), the SCCmec gene of which could not be typed. Overall, our findings showed that Chinese retail RTE foods are likely vehicles for transmission of multidrug-resistant S. aureus and MRSA lineages. This is a serious public health risk and highlights the need to implement good hygiene practices.
Chen, Yong; Zhao, Wei; Liu, Hui; Song, Qing; Wang, Yan; Zhao, Jingya; Zheng, Dongyu; Han, Xuelin; Hu, Xiaohua; Grundmann, Hajo; Han, Li
In 2008, an intensive care unit (ICU) in a large Chinese hospital was moved from a 6-bed old ward to a 20-bed new ward. After the move, the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in patients and environmental sites decreased significantly, but the number of ICU-acquired cas
Claro, Tânia; Galvin, Sandra; Cahill, Orla; Fitzgerald-Hughes, Deirdre; Daniels, Stephen; Humphreys, Hilary
Environmental sampling in hospitals, when required, needs to be reliable. We evaluated different methods of sampling methicillin-resistant Staphylococcus aureus and extended-spectrum β-lactamase-producing Escherichia coli on 5 materials of the hospital setting. Petrifilms and contact plates were superior to swabs for all of the surfaces studied.
Luteijn, J. M.; Hubben, G. A. A.; Pechlivanoglou, P.; Bonten, M. J.; Postma, M. J.
P>A systematic review and meta-analysis were performed to determine and compare the sensitivity and specificity of PCR-based and culture-based diagnostic tests for methicillin-resistant Staphylococcus aureus (MRSA). Our analysis included 74 accuracy measurements from 29 publications. Nine tests were
A multiplex PCR method was developed for simultaneous detection of the genes encoding methicillin resistance (mecA), staphylococcal enterotoxins A, B and C (sea, seb and sec), coagulase (coa) and 16S rRNA. The primers for amplification of the 16S rRNA gene were specific for Staphylococcus spp., and ...
Martins, Ana; Couto, Isabel; Aagaard, Lone;
Our previous studies demonstrated that exposure of a bacterium to increasing concentrations of an antibiotic would increase resistance to that antibiotic as a consequence of activating efflux pumps. This study utilises the same approach; however, it employs the methicillin-resistant Staphylococcus...
Buss, Bryan F.; Mueller, Shawn W.; Theis, Max; Keyser, Alison; Safranek, Thomas J.
Methicillin-resistant "Staphylococcus aureus" (MRSA) is an emerging cause of skin and soft-tissue infections among athletes. To determine statewide incidence among high school athletes, we surveyed all 312 Nebraska high schools regarding sport programs offered, program-specific participation numbers, number of athletes with…
Full Text Available Abstract We present a case of a 77-year old female who had undergone a coronary artery bypass grafting with an aortic valve replacement and developed three month later a Methicillin-Resistant Staphylococcus aureus (MRSA sternal wound infection which was successful treated with Daptomycin combined with vacuum-assisted closure (VAC.
Köck, R; Harlizius, J; Bressan, N; Laerberg, R; Wieler, L H; Witte, W; Deurenberg, R H; Voss, A; Becker, K; Friedrich, A W
The aim of this study was to evaluate the prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) among pigs and estimate the impact of this animal reservoir on human healthcare. Nasal swabs were derived from 1,600 pigs at 40 German farms. The MRSA were charact
Feltrin, Fabiola; Alba, Patricia; Kraushaar, Britta
Pandemic methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 97 (CC97) lineages originated from livestock-to-human host jumps. In recent years, CC97 has become one of the major MRSA lineages detected in Italian farmed animals. The aim of this study was to characterize and analyze di...
Thirty-six methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates from renal patients were genetically characterized by DNA microarray analysis and spa typing. The isolates were highly clonal, belonging mainly to ST22-MRSA-IV. The immune evasion and enterotoxin gene clusters were found in 29\\/36 (80%) and 33\\/36 (92%) isolates, respectively.
Buss, Bryan F.; Connolly, Susan
Though historically confined to hospital settings, methicillin-resistant Staphylococcus aureus (MRSA) has received increasing attention in the wider community, particularly among athletes. A 2007-2008 investigation in Nebraska concluded that MRSA skin infections were an emerging problem among the state's student athletes. Statewide…
Mekonnen, Solomon A; Palma Medina, Laura M; Glasner, Corinna
Methicillin-resistant Staphylococcus aureus (MRSA) is the common name for a heterogeneous group of highly drug-resistant staphylococci. Two major MRSA classes are distinguished based on epidemiology, namely community-associated (CA) and hospital-associated (HA) MRSA. Notably, the distinction of CA...
Christiansen, Mette Theilgaard; Kaas, Rolf Sommer; Chaudhuri, Roy R.
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) Sequence Type 398 (ST398) is an opportunistic pathogen that is able to colonize and cause disease in several animal species including humans. To better understand the adaptation, evolution, transmission and pathogenic...
Bischof, Larry J.; Lapsley, Linda; Fontecchio, Karen; Jacosalem, Dollie; Young, Carol; Hankerd, Rosemary; Newton, Duane W.
To select a method for detecting methicillin-resistant Staphylococcus aureus (MRSA) in nasal swabs, we compared BD GeneOhm MRSA PCR and various culture media (mannitol salt agar with cefoxitin, MRSASelect, CHROMagar MRSA, and Spectra MRSA). While PCR detection of MRSA was more rapid, MRSASelect and Spectra MRSA demonstrated performance equivalent to that of PCR with maximal detection at 24 h.
Terp, Sophie; Krishnadasan, Anusha; Bowen, William; Joo, Julianne; Furoy, Daniel; Chan, Joseph; Moran, Gregory; Talan, David
Introduction of a rapid methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction assay, with physician education and pharmacist guidance, did not significantly reduce excessive empiric prescription of MRSA-active antibiotics despite the test's accuracy and potential to substantially reduce inappropriate antibiotic use.
Full Text Available According to the existing literature, a heterogeneous sequence type (ST or clones of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA circulate in Europe. In Europe, the European clone that belongs to sequence type ST80 is predominant.
J.E. Clarridge III (Jill); R.A. Harrington (Robert Alex); M.C. Roberts (Marilyn); O.O. Soge (Olusegun); K. Maquelin (Kees)
textabstractThe anterior nares are the site of choice for the Veterans Administration methicillin-resistant Staphylococcus aureus (MRSA) surveillance program; however, a correlation between nares colonization and concomitant wound infections has not been well established. The purpose of this study w
Cavaco, L. M.; Hasman, H.; Stegger, M.; Andersen, P. S.; Skov, R.; Fluit, A. C.; Ito, T.; Aarestrup, F. M.
We recently reported a phenotypic association between reduced susceptibility to zinc and methicillin resistance in Staphylococcus aureus CC398 isolates from Danish swine (F. M. Aarestrup, L. M. Cavaco, and H. Hasman, Vet. Microbiol. 142: 455-457, 2009). The aim of this study was to identify the gene
Thirty-six methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates from renal patients were genetically characterized by DNA microarray analysis and spa typing. The isolates were highly clonal, belonging mainly to ST22-MRSA-IV. The immune evasion and enterotoxin gene clusters were found in 29\\/36 (80%) and 33\\/36 (92%) isolates, respectively.
Knox, J; Van Rijen, M; Uhlemann, A-C; Miller, M; Hafer, C; Vavagiakis, P; Shi, Q; Johnson, P D R; Coombs, G; Kluytmans-Van Den Bergh, M; Kluytmans, J; Bennett, C M; Lowy, F D
Diverse strain types of methicillin-resistant Staphylococcus aureus (MRSA) cause infections in community settings worldwide. To examine heterogeneity of spread within households and to identify common risk factors for household transmission across settings, primary data from studies conducted in New
M.C. Vos (Margreet); M.D. Behrendt (Myra); D.C. Melles (Damian); F.P.N. Mollema (Femke); W. de Groot (Woutrinus); G. Parlevliet (Gerard); A. Ott (Alewijn); D. Horst-Kreft (Deborah); A.F. van Belkum (Alex); H.A. Verbrugh (Henri)
textabstractOBJECTIVE: To evaluate the effectiveness of a rigorous search and destroy policy for controlling methicillin-resistant Staphylococcus aureus (MRSA) infection or colonization. DESIGN: Hospital-based observational follow-up study. SETTING: Erasmus University Medical Center Rotterdam, a 1,2
R. Coello; J.R. Glynn (Judith); J. J. Picazo; J. Fereres; C. Gaspar
textabstractIn hospital outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) many patients are initially colonized without infection. The reasons why some progress to infection while others do not are not known. A cohort of 479 hospital patients, initially only colonized with MRSA, was fo
Brandt, Karin M; Mellmann, Alexander; Ballhausen, Britta; Jenke, Christian; van der Wolf, Peter J; Broens, Els M; Becker, Karsten; Köck, Robin
BACKGROUND: The increasing occurrence of livestock-associated (LA) methicillin-resistant Staphylococcus aureus (MRSA) associated with the clonal complex (CC) 398 within the past years shows the importance of standardized and comparable typing methods for the purposes of molecular surveillance and
Ronco, Troels; Stegger, Marc; Pedersen, Karl
Livestock-associated (LA) methicillin-resistant Staphylococcus aureus (MRSA) strains of sequence type 398 (ST398) colonize both humans and various livestock species. In 2016, an ST398 LA-MRSA isolate (Sa52) was collected from a Danish dairy cow with mastitis, and here, we report the draft genome...
Buss, Bryan F.; Connolly, Susan
Though historically confined to hospital settings, methicillin-resistant Staphylococcus aureus (MRSA) has received increasing attention in the wider community, particularly among athletes. A 2007-2008 investigation in Nebraska concluded that MRSA skin infections were an emerging problem among the state's student athletes. Statewide surveillance…
Ferreira, Dennis de Carvalho; da Silva, Glaucilene Rodrigues; Cavalcante, Fernanda Sampaio; do Carmo, Flavia Lima; Fernandes, Leonardo Alexandre; Moreira, Suelen; Leal Passos, Mauro Romero; Vieira Colombo, Ana Paula; Netto dos Santos, Katia Regina
Staphylococcus aureus is an important cause of infections and HIV-infected individuals are frequently susceptible to this pathogen. The aim of this study was to perform a systematic review to identify both the risk factors associated with colonization/infection by methicillin-resistant S. aureus in
Wassenberg, Marjan; Kluytmans, Jan; Erdkamp, Stephanie; Bosboom, Ron; Buiting, Anton; van Elzakker, Erika; Melchers, Willem; Thijsen, Steven; Troelstra, Annet; Vandenbroucke-Grauls, Christina; Visser, Caroline; Voss, Andreas; Wolffs, Petra; Wulf, Mireille; van Zwet, Ton; de Wit, Ardine; Bonten, Marc
Introduction: Pre-emptive isolation of suspected methicillin-resistant Staphylococcus aureus (MRSA) carriers is a cornerstone of successful MRSA control policies. Implementation of such strategies is hampered when using conventional cultures with diagnostic delays of three to five days, as many non-
Wassenberg, M. W. M.; Kluytmans, J. A. J. W.; Bosboom, R. W.; Buiting, A. G. M.; van Elzakker, E. P. M.; Melchers, W. J. G.; Thijsen, S. F. T.; Troelstra, A.; Vandenbroucke-Grauls, C. M. J. E.; Visser, C. E.; Voss, A.; Wolffs, P. F. G.; Wulf, M. W. H.; van Zwet, A. A.; de Wit, G. A.; Bonten, M. J. M.
Multiple body site screening and pre-emptive isolation of patients at risk for methicillin-resistant Staphylococcus aureus (MRSA) carriage are considered essential for control of nosocomial spread. The relative importance of extranasal screening when using rapid diagnostic testing (RDT) is unknown.
V. Neela (Vasanthakumari); H. Ghasemzadeh Moghaddam (Hamed); A.F. van Belkum (Alex); D. Horst-Kreft (Deborah); N.S. Mariana (Nor Shamsudin); E. Ghaznavi Rad (Ehsanollah)
textabstractMethicillin-resistant Staphylococcus aureus (MRSA) from Malaysia were shown to possess staphylococcal cassette chromosome mec (SCCmec)-III and IIIA. Spa sequencing and multi-locus sequence typing (MLST) documented t037 and ST 239 (CC8) for 83.3% of the isolates. This confirms
Valvatne, Håvard; Rijnders, Michelle I A; Budimir, Ana; Boumans, Marie-Louise; de Neeling, Albert J; Beisser, Patrick S; Stobberingh, Ellen E; Deurenberg, Ruud H
For us to assess the spread of methicillin-resistant Staphylococcus aureus (MRSA), typing of the staphylococcal cassette chromosome mec (SCCmec) is a valuable addition to existing typing methods, such as multilocus sequence typing (MLST). Traditional SCCmec typing assays, that is, that of Oliveira
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.
Full Text Available BACKGROUND: In 2004, an outbreak of the USA300 strain of methicillin-resistant Staphylococcus aureus (MRSA was identified in persons with histories of homelessness, illicit drug use or incarceration in the Calgary Health Region (Calgary, Alberta. A prevalence study was conducted to test the hypotheses for factors associated with USA300 colonization or infection.
Fernandez, Silvina; Murzicato, Sofía; Sandoval, Orlando; Fernández-Canigia, Liliana; Mollerach, Marta
Community-acquired methicillin-resistant Staphylococcus aureus is the first cause of skin and soft tissue infections, but can also produce severe diseases such as bacteremia, osteomyelitis and necrotizing pneumonia. Some S. aureus lineages have been described in cases of necrotizing pneumonia worldwide, usually in young, previously healthy patients. In this work, we describe a fatal case of necrotizing pneumonia due to community-acquired methicillin-resistant S. aureus clone ST30-SCCmecIVc-spat019-PVL positive in an immunocompetent adult patient. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.
Brill, G. E.; Egorova, A. V.; Bugaeva, I. O.; Tuchina, E. S.; Morozov, O. A.; Ponomaryov, G. V.; Ushakova, O. V.
The influence of red laser irradiation on the growth of colonies of methicillin-resistant strain of Staphylococcus aureus and photodynamic effects of the photosensitizers Photoditazine and Dimegin were performed. It was established that the red semiconductor laser (λ - 660 nm, 100 mW/cm2) at 10-, 15- and 30-mins exposure, has a direct bacteriostatic action on the growth of S. aureus. Pre-treatment of bacterial cells by Photoditazine significantly enhances the inhibitory effect. The photosensitizing action of Dimegin does not appear at influence on methicillin-resistant S. aureus.
Full Text Available Community-acquired methicillin-resistant Staphylococcus aureus is the first cause of skin and soft tissue infections, but can also produce severe diseases such as bacteremia, osteomyelitis and necrotizing pneumonia. Some S. aureus lineages have been described in cases of necrotizing pneumonia worldwide, usually in young, previously healthy patients. In this work, we describe a fatal case of necrotizing pneumonia due to community-acquired methicillin-resistant S. aureus clone ST30-SCCmecIVc-spat019-PVL positive in an immunocompetent adult patient.
Nübel, Ulrich; Roumagnac, Philippe; Feldkamp, Mirjam
of mutational steps that define geographically associated clades. These clades are not concordant with previously described groupings based on staphylococcal protein A gene (spa) typing. By mapping the number of independent imports of the staphylococcal cassette chromosome methicillin-resistance island, we also...... show that import has occurred on at least 23 occasions within this single sequence type and that the progeny of such recombinant strains usually are distributed locally rather than globally. These results provide strong evidence that geographical spread of MRSA over long distances and across cultural...
Tattevin, P; Basuino, L; Bauer, D; Diep, B A; Chambers, H F
Beta lactam agents are the most active drugs for the treatment of streptococci and methicillin-susceptible Staphylococcus aureus endocarditis. However, methicillin-resistant S. aureus (MRSA) is resistant to all beta lactam agents licensed to date, and alternative treatments are limited. Ceftobiprole is a novel broad-spectrum cephalosporin that binds with high affinity to PBP 2a, the penicillin binding protein that mediates the methicillin resistance of staphylococci and is active against MRSA. Ceftobiprole was compared to vancomycin, daptomycin, and linezolid in a rabbit model of MRSA aortic valve endocarditis caused by the homogeneously methicillin-resistant laboratory strain COL. Residual organisms in vegetations were significantly fewer in ceftobiprole-treated rabbits than in any other treatment group (Pceftobiprole-treated rabbits than in linezolid- and vancomycin-treated animals (Pceftobiprole may represent a significant therapeutic advance over currently available agents for the treatment of MRSA endocarditis.
Chanchaithong, Pattrarat; Prapasarakul, Nuvee; Perreten, Vincent; Schwendener, Sybille
A novel staphylococcal cassette chromosome mec (SCCmec) composite island (SCCmecAI16-SCCczrAI16-CI) was identified in Staphylococcus pseudintermedius. Four integration site sequences for SCC subdivided the 60,734-bp island into 41,232-bp SCCmecAI16, 19,400-bp SCCczrAI16, and 102-bp SCC-likeAI16 elements. SCCmecAI16 represents a new combination of ccrA1B3 genes with a class A mec complex. SCCczrAI16 contains ccrA1B6 and genes related to restriction modification and heavy metal resistance. SCCmecAI16-SCCczrAI16-CI was found in methicillin-resistant S. pseudintermedius sequence type 112 (ST112) and ST111 isolated from dogs and veterinarians in Thailand.
Moon, Dong Chan; Kim, Byung-Yong; Nam, Hyang-Mi; Jang, Geum-Chan; Jung, Suk-Chan; Lee, Hee-Soo; Park, Yong-Ho; Lim, Suk-Kyung
Methicillin-resistant Staphylococcus aureus (MRSA), the major causative agent of nosocomial infection, has also been reported from non-human sources. A sequence type (ST) 541 MRSA isolate designated K12PJN53 was isolated from a healthy pig in 2012. The genome of K12PJN53 consists of 44 contiguous sequences (contigs), totalling 2,880,108 bases with 32.88% GC content. Among the annotated contigs, 14, 17, and 18 contained genes related to antimicrobial resistance, adherence, and toxin genes, respectively. The genomic distance of strain K12PJN53 was close to the ST398 strains. This is the first report of the draft genome sequence of a novel livestock-associated MRSA ST541 strain.
dos Santos, Teresa Pires; Damborg, Peter; Moodley, Arshnee;
Background and rationale: Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is a major cause of infections in dogs, also posing a zoonotic risk to humans. This systematic review aimed to determine the global epidemiology of MRSP and provide new insights into the population structure...... included in the review. MRSP represented 76% of the 1428 isolates characterized by the current MLST scheme. The population of S. pseudintermedius was highly diverse and included five major MRSP clonal complexes (CCs). CC71, previously described as the epidemic European clone, is now widespread worldwide...... has an epidemic population structure, in which five successful MRSP lineages with specific traits regarding antimicrobial resistance, genetic diversity and geographical distribution have emerged upon a weakly clonal background through acquisition of SCCmec and other mobile genetic elements....
Moodley, Arshnee; Nielsen, Søren Saxmose; Guardabassi, Luca
An in vivo experiment was conducted to evaluate the effects of tetracycline and zinc on pig colonization and transmission of methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 398. Eight piglets naturally colonized with MRSA ST398 and 8 MRSA-negative piglets of the same age...... and breed were assigned to three groups treated with tetracycline and zinc (Group 1), zinc (Group 2) or tetracycline alone (Group 3) and one non-treated group (Group 4), each containing two MRSA-positive and two MRSA-negative animals. Two additional non-treated control groups composed of only MRSA......-positive (Group 5) and MRSA-negative (Group 6) animals were used to check for stability of MRSA carriage status. Nasal swabs and environmental wipes were collected on Days 0, 7, 14, and 21, and the occurrence of MRSA in each sample was quantified by bacteriological counts on Brilliance™ MRSA agar. Significantly...
Naser Jarrar; Awni Abu-Hijleh; Kamel Adwan
Objective: To determine the antimicrobial activity of rosemary (Rosmarinus officinalis L.) and to investigate the synergistic effects of this extract combined with ceforuxime against methicillin-resistantStaphylococcus aureus (MRSA).Methods: The inhibitory and bactericidal activities of rosemary ethanol extract, alone and in combination with cefuroxime, were studied.Results: The minimum inhibitory concentrations (MICs) of the ethanol extract of rosemary were in the range of 0.39-3.13 mg/mL. The minimum bactericidal concentrations (MBCs) were usually equal to or double that MICs. The antimicrobial activity of combinations of the ethanol extract of rosemary and cefuroxime indicated their synergistic effects against all MRSAs.Conclusions: The present work clearly demonstrates that rosemary has a key role in the elevation of susceptibility toβ-lactams.
Lone, Rubina; Syed, Khurshid; Abdul, Rashid; Sheikh, Sajjad Ahmed; Shah, Faisal
Acanthamoeba species can cause a chronic, progressive, ulcerative keratitis of the eye, which is not responsive to the usual antimicrobial treatment and is frequently mistaken for stromal herpes keratitis. Acanthamoeba keratitis continues to be a burgeoning and unsolved problem. Although soft contact lens wear is reported as the major risk factor in other parts of the world, reports from India suggest that acanthamoeba keratitis is more common among non-contact lens wearers. An unusual case of coinfection with Acanthamoeba and methicillin resistant staphylococcus aureus (MRSA) as causes of corneal keratitis in a contact lens wearer from Kashmir, India, is reported. Recent findings have shown that MRSA uses amoebae to spread, sidestepping hospital and other protection measures. Cysts of the isolated Acanthamoeba tolerated an incubation temperature of 40°C, indicating a pathogenic species. This case highlights the importance of culture methods in the diagnosis of corneal infection and the choice of treatment regimen.
Edmundson, S P
Methicillin-resistant Staphylococcus aureus (MRSA) infections are associated with increased mortality, costs and length of stay compared to non-MRSA infections. This observational 4-year study analyses the impact of screening and treating orthopaedic healthcare workers for MRSA colonisation. A total of 1,011 swabs were taken from 566 healthcare workers. Positive healthcare workers were treated with topical mupirocin to both anterior nares. The prevalence of MRSA colonisation on initial testing was 4.77%. The rate of positive MRSA colonisation of those tested on more than one occasion fell from 5.88% to 2.71% (p = 0.055) on subsequent screening. All healthcare workers receiving treatment were successfully cleared of colonisation; however, some required more than one course of treatment. These results show that there could be a role for screening and treating orthopaedic staff for MRSA colonisation as part of a strategy to reduce the prevalence of MRSA infections in orthopaedic units.
Usman Amin, Muhammad; Khurram, Muhammad; Khan, Taj Ali; Faidah, Hani S; Ullah Shah, Zia; Ur Rahman, Shafiq; Haseeb, Abdul; Ilyas, Muhammad; Ullah, Naseem; Umar Khayam, Sahibzada Muhammad; Iriti, Marcello
The present study was designed to evaluate the effects of flavonoids luteolin (L) and quercetin + luteolin (Q + L) in combination with commonly used antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates and S. aureus (ATCC 43300). Minimum inhibitory concentrations (MICs) of L and Q + L, as well as the MICs of flavonoids in combination with antibiotics were determined and results showed an increased activity of flavonoids with antibiotics. The synergistic, additive, or antagonistic relationships between flavonoids (L and Q + L) and antibiotics were also evaluated, and additive and synergistic effects were observed for some antibiotic + flavonoid combinations. In addition, some combinations were also found to damage the bacterial cytoplasmic membrane, as assessed through potassium leakage assay. The effects of flavonoids and flavonoids + antibiotics on mecA gene mutations were also tested, and no functional variation was detected in the coding region.
Hammond, Timothy G.; Birdsall, Holly H.; Hammond, Jeffrey S.; Allen, Patricia L.
This study addresses controls for an assay of bacterial virulence that has been optimized for space flight studies. Caenorhabditis elegans (C. elegans) worms ingest microorganisms, but are also killed by virulent bacteria. Virulence is assessed by the number of bacteria surviving in co-culture with C. elegans , as measured by optical density at 620 nm. Co -cultures of Methicillin-resistant Staphylococcus aureus (MRSA) with C. elegans have a higher OD620 than MRSA grown alone, which could reflect debris from dead worms and/or enhanced growth of the MRSA in response to worm-derived factors. The use of media conditioned by pre-incubation with worms demonstrated the presence of temperature-stable factors that change MRSA growth in a strain-dependent manner. Some sources of deionized water contain an undefined antibacterial activity present in conditioned, but not fresh untreated media.
Manukumar, H M; Umesha, S
Food-borne methicillin resistant Staphylococcus aureus (MRSA) is involved in two-fold higher mortality rate compared to methicillin susceptible S. aureus (MSSA). Eventhough Mysuru recognized as cleanest city in the world, prevalence of food contamination is not detailed. The aim is to screen food samples from Mysuru area and to characterize MRSA strain, employing MALDI-Biotyper, multiplex PCR to distinguish between MRSA and MSSA by PCR-coupled single strand conformation polymorphism (PCR-SSCP). Of all the food-borne pathogens, S. aureus contamination accounts for 94.37 ± 0.02% (P 99%), robust (<2 min), and alternative tool for pathogen identification, and we developed a PCR-SSCP technique for rapid detection of MSSA and MRSA strains.
André, Egidio Domingos; Pereira, Renata Freire Alves; Snyder, Robert Eugene; Machado, Thamiris Santana; André, Lialyz Soares Pereira; Cardoso, Claudete Aparecida Araújo; Aguiar-Alves, Fábio
CC398 is a livestock-associated Staphylococcus aureus. However, it has also been isolated from humans with no previous contact with livestock. A surveillance of methicillin-resistant S. aureus colonisation among children attending public day care centres and hospitals in Niterói and Rio de Janeiro, Brazil, between 2011 and 2013, resulted in the isolation of six cases of CC398 from individuals with no previous exposure to livestock. These isolates showed a high frequency of the erm(C) gene (4/6, 66.7%) with induced resistance to clindamycin, and a relatively high frequency of SEs and lukS/lukF genes. These results suggest the emergence of a non-LA-CC398 in Brazil.
Full Text Available The crude extracts of plants from Asteraceae and Lamiaceae family and essential oils from Salvia officinalis and Salvia sclarea were studied for their antibacterial as well as antibiotic resistance modifying activity. Using disc diffusion and broth microdilution assays we determined higher antibacterial effect of three Salvia spp. and by evaluating the leakage of 260 nm absorbing material we detected effect of extracts and, namely, of essential oils on the disruption of cytoplasmic membrane. The evaluation of in vitro interactions between plant extracts and oxacillin described in terms of fractional inhibitory concentration (FIC indices revealed synergistic or additive effects of plant extracts and clearly synergistic effects of essential oil from Salvia officinalis with oxacillin in methicillin-resistant Staphylococcus epidermidis.
van de Vijver, L P L; Tulinski, P; Bondt, N; Mevius, D; Verwer, C
The prevalence of the methicillin-resistant Staphylococcus aureus (MRSA) among conventional pig herds in the Netherlands is high (around 71%). Nevertheless, information about the prevalence of MRSA among organic pig herds is lacking. Here, we report a study on 24 of the 49 organic pig herds in the Netherlands. The prevalence of MRSA positive herds showed to be 21%. The genetic characteristics of the MRSA isolates were similar to MRSA CC398 described in conventional pigs except one exceptional HA-MRSA CC30 found in one herd, which was presumably caused by human to animal transmission. This resulted in a prevalence of MRSA CC398 in the organic herds of 16.7%.
Bartels, Mette Damkjaer; Petersen, Andreas; Worning, Peder
spa typing of methicillin-resistant Staphylococcus aureus (MRSA) has traditionally been done by PCR amplification and Sanger sequencing of the spa repeat region. At Hvidovre Hospital, Denmark, whole-genome sequencing (WGS) of all MRSA isolates has been performed routinely since January 2013......, and an in-house analysis pipeline determines the spa types. Due to national surveillance, all MRSA isolates are sent to Statens Serum Institut, where the spa type is determined by PCR and Sanger sequencing. The purpose of this study was to evaluate the reliability of the spa types obtained by 150-bp paired......-end Illumina WGS. MRSA isolates from new MRSA patients in 2013 (n = 699) in the capital region of Denmark were included. We found a 97% agreement between spa types obtained by the two methods. All isolates achieved a spa type by both methods. Nineteen isolates differed in spa types by the two methods, in most...
Pompilio, Arianna; Pomponio, Stefano; Di Vincenzo, Valentina; Crocetta, Valentina; Nicoletti, Marcello; Piovano, Marisa; Garbarino, Juan A; Di Bonaventura, Giovanni
Three secondary metabolites of lichens - usnic acid, atranorin and fumarprotocetraric acid - were evaluated for their in vitro antibacterial and antibiofilm activities against three strains each of methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MRSA) from cystic fibrosis patients. Antibacterial activity was assessed by broth microdilution, while antibiofilm activity was evaluated by spectrophotometry or viable count. Usnic acid was significantly more active than atranorin against planktonic cells, while fumarprotocetraric acid exhibited no activity. Atranorin was the most effective in counteracting adhesion to polystyrene, although usnic acid was more active against MRSA. Usnic acid and atranorin showed comparable activity against biofilm formation, although atranorin was more active against MRSA. Usnic acid was significantly more active than atranorin against preformed biofilms. Secondary metabolites of lichens may be considered to be 'lead compounds' for the development of novel molecules for the treatment of S. aureus infections in cystic fibrosis patients.
Böcher, Sidsel; Gervelmeyer, Andrea; Monnet, Dominique;
The proportion of methicillin-resistant Staphylococcus aureus (MRSA) in Denmark has been below 1% for more than 30 years. However, a marked increase in community-onset MRSA (CO-MRSA) started in 2002. To identify possible risk factors for CO-MRSA infections, a nationwide case-control study...... was conducted in 2004. Cases (34) were patients with CO-MRSA infections; controls (87) were patients with community-onset methicillin-sensitive S. aureus infections (CO-MSSA). Demographic and clinical data and exposures to possible risk factors during the last 24 months were collected with a structured...... the last 6 months, and 51% and 31%, respectively, had been hospitalized within the previous year. In a multivariate analysis, non-Danish origin, defined as being from or having parents from outside Denmark, was the only independent risk factor for CO-MRSA infection (OR 30.5, 95% CI 3.6-257.3). Prior...
Muhammad Usman Amin
Full Text Available The present study was designed to evaluate the effects of flavonoids luteolin (L and quercetin + luteolin (Q + L in combination with commonly used antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA clinical isolates and S. aureus (ATCC 43300. Minimum inhibitory concentrations (MICs of L and Q + L, as well as the MICs of flavonoids in combination with antibiotics were determined and results showed an increased activity of flavonoids with antibiotics. The synergistic, additive, or antagonistic relationships between flavonoids (L and Q + L and antibiotics were also evaluated, and additive and synergistic effects were observed for some antibiotic + flavonoid combinations. In addition, some combinations were also found to damage the bacterial cytoplasmic membrane, as assessed through potassium leakage assay. The effects of flavonoids and flavonoids + antibiotics on mecA gene mutations were also tested, and no functional variation was detected in the coding region.
Mojsoska, Biljana; Cruz, João C. S.; Donadio, Stefano; Jenssen, Håvard
We used the fruit fly Drosophila melanogaster as a cost-effective in vivo model to evaluate the efficacy of novel antibacterial peptides and peptoids for treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. A panel of peptides with known antibacterial activity in vitro and/or in vivo was tested in Drosophila. Although most peptides and peptoids that were effective in vitro failed to rescue lethal effects of S. aureus infections in vivo, we found that two lantibiotics, nisin and NAI-107, rescued adult flies from fatal infections. Furthermore, NAI-107 rescued mortality of infection with the MRSA strain USA300 with an efficacy equivalent to that of vancomycin, a widely applied antibiotic for the treatment of serious MRSA infections. These results establish Drosophila as a useful model for in vivo drug evaluation of antibacterial peptides. PMID:27381394
Mocan, Lucian; Ilie, Ioana; Matea, Cristian; Tabaran, Flaviu; Kalman, Ersjebet; Iancu, Cornel; Mocan, Teodora
Systemic infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and other bacteria are responsible for millions of deaths worldwide, and much of this mortality is due to the rise of antibiotic-resistant organisms as a result of natural selection. Gold nanoparticles synthesized using the standard wet chemical procedure were photoexcited using an 808 nm 2 W laser diode and further administered to MRSA bacteria. Flow cytometry, transmission electron microscopy, contrast phase microscopy, and fluorescence microscopy combined with immunochemical staining were used to examine the interaction of the photoexcited gold nano-particles with MRSA bacteria. We show here that phonon-phonon interactions following laser photoexcitation of gold nanoparticles exhibit increased MRSA necrotic rates at low concentrations and short incubation times compared with MRSA treated with gold nanoparticles alone. These unique data may represent a step forward in the study of bactericidal effects of various nanomaterials, with applications in biology and medicine.
Altman, D. R.; Sebra, R.; Hand, J.; Attie, O.; Deikus, G.; Carpini, K. W. D.; Patel, G.; Rana, M.; Arvelakis, A.; Grewal, P.; Dutta, J.; Rose, H.; Shopsin, B.; Daefler, S.; Schadt, E.; Kasarskis, A.; van Bakel, H.; Bashir, A.; Huprikar, S.
Donor-derived bacterial infection is a recognized complication of solid organ transplantation (SOT). The present report describes the clinical details and successful outcome in a liver transplant recipient despite transmission of methicillin-resistant Staphylococcus aureus (MRSA) from a deceased donor with MRSA endocarditis and bacteremia. We further describe whole genome sequencing (WGS) and complete de novo assembly of the donor and recipient MRSA isolate genomes, which confirms that both isolates are genetically 100% identical. We propose that similar application of WGS techniques to future investigations of donor bacterial transmission would strengthen the definition of proven bacterial transmission in SOT, particularly in the presence of highly clonal bacteria such as MRSA. WGS will further improve our understanding of the epidemiology of bacterial transmission in SOT and the risk of adverse patient outcomes when it occurs. PMID:25250641
Haba, Ester; Bouhdid, Samira; Torrego-Solana, Noelia; Marqués, A M; Espuny, M José; García-Celma, M José; Manresa, Angeles
This work examines the influence of essential oil composition on emulsification with rhamnolipids and their use as therapeutic antimicrobial agents against two opportunistic pathogens, methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans. Rhamnolipids, produced by Pseudomonas aeruginosa, with waste frying oil as the carbon source, were composed of eight rhamnolipid homologues. The rhamnolipid mixture was used to produce emulsions containing essential oils (EOs) of Melaleuca alternifolia, Cinnamomum verum, Origanum compactum and Lavandula angustifolia using the titration method. Ternary phase diagrams were designed to evaluate emulsion stability, which differed depending on the essential oil. The in vitro antimicrobial activity of the EOs alone and the emulsions was evaluated. The antimicrobial activity presented by the essential oils alone increased with emulsification. The surface properties of rhamnolipids contribute to the positive dispersion of EOs and thus increase their availability and antimicrobial activity against C. albicans and S. aureus. Therefore, rhamnolipid-based emulsions represent a promising approach to the development of EO delivery systems.
Nicholson, Tracy L; Shore, Sarah M; Smith, Tara C; Frana, Timothy S; Fraena, Timothy S
Methicillin-resistant Staphylococcus aureus (MRSA) colonization of livestock animals is common and prevalence rates for pigs have been reported to be as high as 49%. Mechanisms contributing to the persistent carriage and high prevalence rates of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) strains in swine herds and production facilities have not been investigated. One explanation for the high prevalence of MRSA in swine herds is the ability of these organisms to exist as biofilms. In this report, the ability of swine LA-MRSA strains, including ST398, ST9, and ST5, to form biofilms was quantified and compared to several swine and human isolates. The contribution of known biofilm matrix components, polysaccharides, proteins and extracellular DNA (eDNA), was tested in all strains as well. All MRSA swine isolates formed robust biofilms similar to human clinical isolates. The addition of Dispersin B had no inhibitory effect on swine MRSA isolates when added at the initiation of biofilm growth or after pre-established mature biofilms formed. In contrast, the addition of proteinase K inhibited biofilm formation in all strains when added at the initiation of biofilm growth and was able to disperse pre-established mature biofilms. Of the LA-MRSA strains tested, we found ST398 strains to be the most sensitive to both inhibition of biofilm formation and dispersal of pre-formed biofilms by DNaseI. Collectively, these findings provide a critical first step in designing strategies to control or eliminate MRSA in swine herds.
Alexander L A Bloemendaal
Full Text Available BACKGROUND: The mecA gene, encoding methicillin resistance in staphylococci, is located on a mobile genetic element called Staphylococcal Cassette Chromosome mec (SCCmec. Horizontal, interspecies transfer of this element could be an important factor in the dissemination of methicillin-resistant S. aureus (MRSA. Previously, we reported the isolation of a closely related methicillin-susceptible Staphylococcus aureus (MSSA, MRSA and potential SCCmec donor Staphylococcus epidermidis isolate from the same patient. Based on fingerprint techniques we hypothesized that the S. epidermidis had transferred SCCmec to the MSSA to become MRSA. The aim of this study was to show that these isolates form an isogenic pair and that interspecies horizontal SCCmec transfer occurred. METHODOLOGY/RESULTS: Whole genome sequencing of both isolates was performed and for the MSSA gaps were closed by conventional sequencing. The SCCmec of the S. epidermidis was also sequenced by conventional methods. The results show no difference in nucleotide sequence between the two isolates except for the presence of SCCmec in the MRSA. The SCCmec of the S. epidermidis and the MRSA are identical except for a single nucleotide in the ccrB gene, which results in a valine to alanine substitution. The main difference with the closely related EMRSA-16 is the presence of SaPI2 encoding toxic shock syndrome toxin and exfoliative toxin A in the MSSA-MRSA pair. No transfer of SCCmec from the S. epidermidis to the MSSA could be demonstrated in vitro. CONCLUSION: The MSSA and MRSA form an isogenic pair except for SCCmec. This strongly supports our hypothesis that the MRSA was derived from the MSSA by interspecies horizontal transfer of SCCmec from S. epidermidis O7.1.
Tracy L Nicholson
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA colonization of livestock animals is common and prevalence rates for pigs have been reported to be as high as 49%. Mechanisms contributing to the persistent carriage and high prevalence rates of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA strains in swine herds and production facilities have not been investigated. One explanation for the high prevalence of MRSA in swine herds is the ability of these organisms to exist as biofilms. In this report, the ability of swine LA-MRSA strains, including ST398, ST9, and ST5, to form biofilms was quantified and compared to several swine and human isolates. The contribution of known biofilm matrix components, polysaccharides, proteins and extracellular DNA (eDNA, was tested in all strains as well. All MRSA swine isolates formed robust biofilms similar to human clinical isolates. The addition of Dispersin B had no inhibitory effect on swine MRSA isolates when added at the initiation of biofilm growth or after pre-established mature biofilms formed. In contrast, the addition of proteinase K inhibited biofilm formation in all strains when added at the initiation of biofilm growth and was able to disperse pre-established mature biofilms. Of the LA-MRSA strains tested, we found ST398 strains to be the most sensitive to both inhibition of biofilm formation and dispersal of pre-formed biofilms by DNaseI. Collectively, these findings provide a critical first step in designing strategies to control or eliminate MRSA in swine herds.
Zhang, Yifan; Wang, Xiaogang; LeJeune, Jeffrey T; Zervos, Marcus; Bhargava, Kanika
Phenotypic detection of methicillin resistance in coagulase-negative Staphylococcus (CoNS) of animal origin has been challenging due to the heterogeneous expression of mecA. To compare different phenotypic methods in predicting the mecA presence in CoNS, a total of 87 CoNS isolates from agricultural animals were analyzed in this study by agar dilution, disk diffusion, and broth microdilution. mecA was present in 81 CoNS isolates. Broth microdilution demonstrated the highest sensitivity of 100% in predicting the mecA presence, followed by 72.8% by agar dilution and 70.4% by disk diffusion. The results indicate that broth microdilution may be more suitable for predicting the presence of mecA in CoNS from animals than the other two methods, although staphylococcal species may also be a factor affecting the sensitivities of the methods as the top three staphylococcal species in this study were Staphylococcus lentus, Staphylococcus sciuri, and Staphylococcus xylosus (a total of 75 of 87).
D'Lima, Louisa; Friedman, Lisa; Wang, Lu; Xu, Ping; Anderson, Mark; Debabov, Dmitri
Twenty-five serial passages of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus and 50 passages of methicillin-resistant Staphylococcus aureus resulted in no significant increase in NVC-422 MICs, while ciprofloxacin MICs increased 256-fold for E. coli and 32-fold for P. aeruginosa and S. aureus. Mupirocin, fusidic acid, and retapamulin MICs for MRSA increased 64-, 256-, and 16-fold, respectively. No cross-resistance to NVC-422 was observed with mupirocin-, fusidic acid-, and retapamulin-resistant strains.
Double triplex real-time PCR assay for simultaneous detection of Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis, and Staphylococcus haemolyticus and determination of their methicillin resistance directly from positive blood culture bottles.
Kilic, Abdullah; Basustaoglu, A Celal
We developed and validated here a double triplex real-time PCR assay to simultaneously detect and identify Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis, Staphylococcus haemolyticus and their methicillin resistance in a single reaction directly from Gram-positive cocci-in-clusters (GPCs)-positive blood culture bottles. From August 15, 2009 through February 15, 2010, 238 GPC-positive samples were collected and identified by conventional methods as 11 methicillin-resistant S. aureus (MRSA), 28 methicillin-susceptible S. aureus (MSSA), 176 MR coagulase-negative staphylococci (MRCoNS), 21 MSCoNS and two Enterococcus faecalis. The double triplex real-time PCR assay was targeted and detected tuf, nuc and mecA genes in the first tube and atlE, gap and mvaA genes in the second tube which could be run simultaneously. The detection limit of the assay was found at 10(3) CFU/ml for the atleE gene, 10(4) CFU/ml for the mva gene and 10(5) CFU/ml for gap, nuc, mecA and tuf genes based on seeding experiments. All Staphylococcus species except two S. epidermidis were correctly identified by the assay. The double triplex real-time PCR assay quickly and accurately detects S. aureus, S. epidermidis, S. hominis and S. haemolyticus and their methicillin resistance in a single reaction directly from positive blood culture bottles within 83 min.
Luciane Cristina Gelatti
Full Text Available Staphylococcus aureus resistente à meticilina foi inicialmente descrito como um típico microrganismo adquirido em infecções nosocomiais. No entanto, nos últimos anos Staphylococcus aureus resistente à meticilina adquirido na comunidade é causa de infecções de pele e tecidos moles, mas infecções graves como pneumonia e sepse podem ocorrer. Este relato descreve um caso de sepse em criança, complicado com pneumonia secundária a lesão em partes moles por Staphylococcus aureus resistente à meticilina adquirido na comunidade no Sul do Brasil. O paciente foi atendido em Unidade de Emergência com história de ferimento provocado por trauma em membro inferior que evoluiu para celulite, pneumonia e sepse.Methicillin-resistant Staphylococcus aureus was initially described as a typical microorganism acquired in nosocomial infections. However, over recent years, community-acquired methicillin-resistant Staphylococcus aureus has been a cause of skin and soft-tissue infections. Serious infections such as pneumonia and sepsis can also occur. This report describes a case of sepsis in a child that was complicated by pneumonia secondary to soft tissue lesions that were due to community-acquired methicillin-resistant Staphylococcus aureus in southern Brazil. The patient was attended at the Emergency Unit with a history of injury caused by lower-limb trauma that evolved to cellulitis, pneumonia and sepsis.
Sinigalliano Christopher D
Full Text Available Abstract Background Staphylococcus aureus including methicillin resistant S. aureus, MRSA, are human colonizing bacteria that commonly cause opportunistic infections primarily involving the skin in otherwise healthy individuals. These infections have been linked to close contact and sharing of common facilities such as locker rooms, schools and prisons Waterborne exposure and transmission routes have not been traditionally associated with S. aureus infections. Coastal marine waters and beaches used for recreation are potential locations for the combination of high numbers of people with close contact and therefore could contribute to the exposure to and infection by these organisms. The primary aim of this study was to evaluate the amount and characteristics of the shedding of methicillin sensitive S. aureus, MSSA and MRSA by human bathers in marine waters. Results Nasal cultures were collected from bathers, and water samples were collected from two sets of pools designed to isolate and quantify MSSA and MRSA shed by adults and toddlers during exposure to marine water. A combination of selective growth media and biochemical and polymerase chain reaction analysis was used to identify and perform limited characterization of the S. aureus isolated from the water and the participants. Twelve of 15 MRSA isolates collected from the water had identical genetic characteristics as the organisms isolated from the participants exposed to that water while the remaining 3 MRSA were without matching nasal isolates from participants. The amount of S. aureus shed per person corresponded to 105 to 106 CFU per person per 15-minute bathing period, with 15 to 20% of this quantity testing positive for MRSA. Conclusions This is the first report of a comparison of human colonizing organisms with bacteria from human exposed marine water attempting to confirm that participants shed their own colonizing MSSA and MRSA into their bathing milieu. These findings clearly
Bonde, Mette; Jacobsen, Kirstine; Kolmos, Hans Jørn
is a phenothiazine derivate, which is known to restore in vitro susceptibility of MRSA strains to β-lactam antibiotics (e.g. oxacillin) . Previously, we have demonstrated that thioridazine prevents the oxacillin-induced transcription of the resistance determinant mecA in a hospital-associated MRSA isolate leading......Few drugs are available against methicillin-resistant S. aureus (MRSA), and decreased susceptibility among staphylococci to newly introduced agents such as linezolid, daptomycin, and tigecycline has been observed [1-3]. Consequently, new treatment strategies are urgently needed. Thioridazine...... to examine the underlying mechanism we are conducting a global transcriptional analysis of the response of strain USA300 to thioridazine treatment with and without oxacillin. We show that thioridazine by itself elicits extensive transcriptional changes, including pathways involved in amino acid synthesis...
Full Text Available Methicillin resistant Stephylococcus aureus (MRSA infection has now become a major problem in hospitals. We present a case of postoperative infection MRSA where the primary source of the infection was found to be an abdominal mesh that was used to reinforce the abdominal wall. After one year of surgery, the patient developed wound dehiscence and discharge. MRSA was isolated from the wound, mesh, external nares, throat and axilla. Initially she was started on clindamycin and discharged from the hospital. After 5 months, patient came back to the hospital with infection at the same site. The patient was then treated with vancomycin and MRSA clearance. She responded to the treatment with complete healing of the wound and clearance of MRSA.
Guimarães, F F; Manzi, M P; Joaquim, S F; Richini-Pereira, V B; Langoni, H
Cows are probably the main source of contamination of raw milk with Staphylococcus aureus. Mammary glands with subclinical mastitis can shed large numbers of Staph. aureus in milk. Because of the risk of this pathogen to human health as well as animal health, the aim of this paper was to describe an outbreak of mastitis caused by methicillin-resistant Staph. aureus (MRSA), oxacillin-susceptible mecA-positive Staph. aureus (OS-MRSA), and methicillin-susceptible Staph. aureus (MSSA) on a dairy farm. Milk samples were obtained from all quarters, showing an elevated somatic cell count by the California Mastitis Test. The isolates were identified by phenotypic and genotypic methods. Staphylococcus spp. were isolated from 53% (61/115) of the milk samples, with 60 isolates identified as Staph. aureus (98.4%) and 1 isolate identified as Staphylococcus epidermidis (1.6%). The presence of the mecA gene was verified in 48.3% of Staph. aureus isolates. Of the Staph. aureus isolates, 23.3% were MRSA and 25.0% were OS-MRSA. The total of mastitis cases infected with MRSA was 12.2%. The detection of this large percentage of mastitis cases caused by MRSA and OS-MRSA is of great concern for the animals' health, because β-lactams are still the most important antimicrobials used to treat mastitis. In addition, Staph. aureus isolates causing bovine mastitis represent a public health risk.
Couto, Natacha; Belas, Adriana; Couto, Isabel; Perreten, Vincent; Pomba, Constança
Forty methicillin-resistant and -susceptible Staphylococcus pseudintermedius (MRSP and MSSP, respectively) from colonization and infection in dogs and cats were characterized for clonality, antimicrobial, and biocide susceptibility. MSSP were genetically more diverse than MRSP by multi-locus sequence typing and pulsed-field gel electrophoresis. Three different spa types (t06, t02, t05) and two SCCmec types (II-III and V) were detected in the MRSP isolates. All MRSP and two MSSP strains were multidrug-resistant. Several antibiotic resistance genes (mecA, blaZ, tet(M), tet(K), aac(6')-Ie-aph(2')-Ia, aph(3')-III, ant(6)-Ia, sat4, erm(B), lnu(A), dfr(G), and catp(C221)) were identified by microarray and double mutations in the gyrA and grlA genes and a single mutation in the rpoB gene were detected by sequence analysis. No differences were detected between MSSP and MRSP in the chlorhexidine acetate (CHA) minimum inhibitory concentrations (MICs). However, two MSSP had elevated MIC to triclosan (TCL) and one to benzalkonium chloride and ethidium bromide. One MSSP isolate harboured a qacA gene, while in another a qacB gene was detected. None of the isolates harboured the sh-fabI gene. Three of the biocide products studied had high bactericidal activity (Otodine(®), Clorexyderm Spot Gel(®), Dermocanis Piocure-M(®)), while Skingel(®) failed to achieve a five log reduction in the bacterial counting. S. pseudintermedius have become a serious therapeutic challenge in particular if methicillin- resistance and/or multidrug-resistance are involved. Biocides, like CHA and TCL, seem to be clinically effective and safe topical therapeutic options.
Meeker, Daniel G; Beenken, Karen E; Mills, Weston B; Loughran, Allister J; Spencer, Horace J; Lynn, William B; Smeltzer, Mark S
We used in vitro and in vivo models of catheter-associated biofilm formation to compare the relative activity of antibiotics effective against methicillin-resistant Staphylococcus aureus (MRSA) in the specific context of an established biofilm. The results demonstrated that, under in vitro conditions, daptomycin and ceftaroline exhibited comparable activity relative to each other and greater activity than vancomycin, telavancin, oritavancin, dalbavancin, or tigecycline. This was true when assessed using established biofilms formed by the USA300 methicillin-resistant strain LAC and the USA200 methicillin-sensitive strain UAMS-1. Oxacillin exhibited greater activity against UAMS-1 than LAC, as would be expected, since LAC is an MRSA strain. However, the activity of oxacillin was less than that of daptomycin and ceftaroline even against UAMS-1. Among the lipoglycopeptides, telavancin exhibited the greatest overall activity. Specifically, telavancin exhibited greater activity than oritavancin or dalbavancin when tested against biofilms formed by LAC and was the only lipoglycopeptide capable of reducing the number of viable bacteria below the limit of detection. With biofilms formed by UAMS-1, telavancin and dalbavancin exhibited comparable activity relative to each other and greater activity than oritavancin. Importantly, ceftaroline was the only antibiotic that exhibited greater activity than vancomycin when tested in vivo in a murine model of catheter-associated biofilm formation. These results emphasize the need to consider antibiotics other than vancomycin, most notably, ceftaroline, for the treatment of biofilm-associated S. aureus infections, including by the matrix-based antibiotic delivery methods often employed for local antibiotic delivery in the treatment of these infections.