RESUMO
The surface protein SasX, has a key role in methicillin-resistant Staphylococcus aureus (MRSA) colonization and pathogenesis, and has been associated with the epidemic success of some MRSA clones. To date, only one SasX homologous protein, named SesI, has been described in Staphylococcus epidermidis. In this work, we analyze the occurrence of the sasX gene and its genetic environment in Staphylococcus haemolyticus S. haemolyticus clinical strains (n = 62) were screened for the presence of the sasX gene and its carrier, the prophage Φ SPß-like. A deep characterization was done in one strain (MD43), through which we determined the complete nucleotide sequence for the S. haemolitycus sasX-like gene. Whole genome sequencing of strain MD43 was performed, and the gene, termed here because of its unique attributes, shsA, was mapped to the Φ SPß-like prophage sequence. The shsA gene was detected in 33 out of 62 strains showing an average identity of 92 and 96% with the sasX and sesI genes and at the amino acid level, 88% identity with SasX and 92% identity with SesI. The ~124Kb Φ SPß-like prophage sequence showed a largely intact prophage compared to its counterpart in S. epidermidis strain RP62A, including the sesI insertion site. In conclusion, we identified a new sasX ortholog in S. haemolyticus (shsA). Its horizontal spread from this reservoir could represent an emergent threat in healthcare facilities since so far, no S. aureus sasX+ strains have been reported in Brazil.
Assuntos
Genoma Bacteriano , Staphylococcus haemolyticus/fisiologia , Staphylococcus haemolyticus/patogenicidade , Fatores de Virulência/genética , Brasil , Prófagos/genética , Virulência , Sequenciamento Completo do GenomaRESUMO
BACKGROUND The association between Staphylococcus haemolyticus and severe nosocomial infections is increasing. However, the extent to which fomites contribute to the dissemination of this pathogen through patients and hospital wards remains unknown. OBJECTIVES In the present study, sphygmomanometers and thermometers were evaluated as potential fomites of oxacillin-resistant S. haemolyticus (ORSH). The influence of oxacillin and vancomycin on biofilm formation by ORSH strains isolated from fomites was also investigated. METHODS The presence of ORSH on swabs taken from fomite surfaces in a Brazilian hospital was assessed using standard microbiological procedures. Antibiotic susceptibility profiles were determined by the disk diffusion method, and clonal distribution was assessed in pulsed-field gel electrophoresis (PFGE) assays. Minimum inhibitory concentrations (MICs) of oxacillin and vancomycin were evaluated via the broth microdilution method. Polymerase chain reaction (PCR) assays were performed to detect the mecA and icaAD genes. ORSH strains grown in media containing 1/4 MIC of vancomycin or oxacillin were investigated for slime production and biofilm formation on glass, polystyrene and polyurethane catheter surfaces. FINDINGS ORSH strains comprising five distinct PFGE types were isolated from sphygmomanometers (n = 5) and a thermometer (n = 1) used in intensive care units and surgical wards. ORSH strains isolated from fomites showed susceptibility to only linezolid and vancomycin and were characterised as multi-drug resistant (MDR). Slime production, biofilm formation and the survival of sessile bacteria differed and were independent of the presence of the icaAD and mecA genes, PFGE type and subtype. Vancomycin and oxacillin did not inhibit biofilm formation by vancomycin-susceptible ORSH strains on abiotic surfaces, including on the catheter surface. Enhanced biofilm formation was observed in some situations. Moreover, a sub-lethal dose of vancomycin induced biofilm formation by an ORSH strain on polystyrene. MAIN CONCLUSIONS Sphygmomanometers and thermometers are fomites for the transmission of ORSH. A sub-lethal dose of vancomycin may favor biofilm formation by ORSH on fomites and catheter surfaces.
Assuntos
Humanos , Oxacilina/farmacologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/transmissão , Termômetros/microbiologia , Vancomicina/farmacologia , Infecção Hospitalar/microbiologia , Biofilmes/crescimento & desenvolvimento , Esfigmomanômetros/microbiologia , Staphylococcus haemolyticus/isolamento & purificação , Staphylococcus haemolyticus/efeitos dos fármacos , Staphylococcus haemolyticus/fisiologia , Antibacterianos/farmacologia , Resistência a Medicamentos , Testes de Sensibilidade Microbiana , Infecção Hospitalar/transmissão , Eletroforese em Gel de Campo Pulsado , EletroforeseRESUMO
BACKGROUND: The association between Staphylococcus haemolyticus and severe nosocomial infections is increasing. However, the extent to which fomites contribute to the dissemination of this pathogen through patients and hospital wards remains unknown. OBJECTIVES: In the present study, sphygmomanometers and thermometers were evaluated as potential fomites of oxacillin-resistant S. haemolyticus (ORSH). The influence of oxacillin and vancomycin on biofilm formation by ORSH strains isolated from fomites was also investigated. METHODS: The presence of ORSH on swabs taken from fomite surfaces in a Brazilian hospital was assessed using standard microbiological procedures. Antibiotic susceptibility profiles were determined by the disk diffusion method, and clonal distribution was assessed in pulsed-field gel electrophoresis (PFGE) assays. Minimum inhibitory concentrations (MICs) of oxacillin and vancomycin were evaluated via the broth microdilution method. Polymerase chain reaction (PCR) assays were performed to detect the mecA and icaAD genes. ORSH strains grown in media containing 1/4 MIC of vancomycin or oxacillin were investigated for slime production and biofilm formation on glass, polystyrene and polyurethane catheter surfaces. FINDINGS: ORSH strains comprising five distinct PFGE types were isolated from sphygmomanometers (n = 5) and a thermometer (n = 1) used in intensive care units and surgical wards. ORSH strains isolated from fomites showed susceptibility to only linezolid and vancomycin and were characterised as multi-drug resistant (MDR). Slime production, biofilm formation and the survival of sessile bacteria differed and were independent of the presence of the icaAD and mecA genes, PFGE type and subtype. Vancomycin and oxacillin did not inhibit biofilm formation by vancomycin-susceptible ORSH strains on abiotic surfaces, including on the catheter surface. Enhanced biofilm formation was observed in some situations. Moreover, a sub-lethal dose of vancomycin induced biofilm formation by an ORSH strain on polystyrene. MAIN CONCLUSIONS: Sphygmomanometers and thermometers are fomites for the transmission of ORSH. A sub-lethal dose of vancomycin may favor biofilm formation by ORSH on fomites and catheter surfaces.
Assuntos
Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Fômites/microbiologia , Esfigmomanômetros/microbiologia , Staphylococcus haemolyticus/fisiologia , Termômetros/microbiologia , Infecção Hospitalar/microbiologia , Infecção Hospitalar/transmissão , Farmacorresistência Bacteriana , Eletroforese em Gel de Campo Pulsado , Humanos , Testes de Sensibilidade Microbiana , Oxacilina/farmacologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/transmissão , Staphylococcus haemolyticus/efeitos dos fármacos , Staphylococcus haemolyticus/isolamento & purificação , Vancomicina/farmacologiaRESUMO
Infections with coagulase-negative staphylococci are often related to biofilm formation. This study aimed to detect biofilm formation and biofilm-associated genes in blood culture isolates of Staphylococcus epidermidis and S. haemolyticus. Half (50.6%) of the 85 S. epidermidis isolates carried the icaAD genes and 15.3% the bhp gene, while these numbers were 42.9% and 0 for S. haemolyticus, respectively. According to the plate test, 30 S. epidermidis isolates were biofilm producers and 40% of them were strongly adherent, while only one (6%) of the 17 S. haemolyticus biofilm-producing isolates exhibited a strongly adherent biofilm. The concomitant presence of icaA and icaD was significantly associated with the plate and tube test results (P ≤ 0.0004). The higher frequency of icaA in S. epidermidis and of icaD in S. haemolyticus is correlated with the higher biofilm-producing capacity of the former since, in contrast to IcaD, IcaA activity is sufficient to produce small amounts of polysaccharide. Although this study emphasizes the importance of icaAD and bhp for biofilm formation in S. epidermidis, other mechanisms seem to be involved in S. haemolyticus.
Assuntos
Bacteriemia/microbiologia , Biofilmes/crescimento & desenvolvimento , Genes Bacterianos , Infecções Estafilocócicas/microbiologia , Staphylococcus epidermidis/fisiologia , Staphylococcus haemolyticus/fisiologia , Aderência Bacteriana , Brasil , Hospitais de Ensino , Humanos , Staphylococcus epidermidis/genética , Staphylococcus epidermidis/isolamento & purificação , Staphylococcus haemolyticus/genética , Staphylococcus haemolyticus/isolamento & purificaçãoRESUMO
Staphylococcus haemolyticus is one of the most frequently isolated coagulase-negative staphylococci. The ability to produce biofilm has contributed to its emergence as a nosocomial pathogen. In this study, some growth conditions were tested to determine their influence on biofilm formation. Brain-heart infusion (BHI) broth containing glucose was used to screen 64 clinical strains. A strong biofilm producer strain showed cells surrounded by a thick layer of extracellular matrix. The presence of atlE, fbp, bap, and icaA genes was analyzed. We concluded that S. haemolyticus biofilm production can be increased with cells grown in BHI, and highlighted that it could be an ica-independent process.
Assuntos
Técnicas Bacteriológicas , Biofilmes/crescimento & desenvolvimento , Staphylococcus haemolyticus/genética , Staphylococcus haemolyticus/fisiologia , Biopolímeros/metabolismo , Meios de Cultura/química , Genes Bacterianos , Genótipo , Humanos , Fenótipo , Infecções Estafilocócicas/microbiologia , Staphylococcus haemolyticus/crescimento & desenvolvimento , Staphylococcus haemolyticus/isolamento & purificaçãoRESUMO
Oxacillin-resistant Staphylococcus haemolyticus (ORSH) was found as the most prevalent (77.5%) species of coagulase-negative staphylococci associated with bacteremia in neonates making use of intravenous catheters in an intensive care unit of a Brazilian teaching hospital. Thirty-one blood isolates were confirmed as S. haemolyticus by sequencing of the 16S and clustered in 6 pulsed-field gel electrophoresis types (with 58% of the strains belonging to 2 predominant types B and D). S. haemolyticus was mostly oxacillin-resistant (90.3%) displaying multiresistance profiles (70.4%). However, the mecA gene was undetected in 22.6% strains. ORSH exhibited slime production on Congo-Red agar (67.7%), adherence to polystyrene (96.7%), and glass (87%) surfaces. Interestingly, ica-operon was detected in 58% strains, mostly belonging to the B, D, and F genotypes, which is a significantly higher percentage when compared to other studies conducted at different parts of the globe. Data indicated that ica operon and biofilm-forming ORSH are endemic in Brazilian nosocomial environment.
Assuntos
Bacteriemia/epidemiologia , Infecção Hospitalar/epidemiologia , Farmacorresistência Bacteriana Múltipla , Infecções Estafilocócicas/epidemiologia , Staphylococcus haemolyticus/isolamento & purificação , Bacteriemia/microbiologia , Aderência Bacteriana , Brasil/epidemiologia , Análise por Conglomerados , Infecção Hospitalar/microbiologia , DNA Bacteriano/química , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Genótipo , Hospitais de Ensino , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Dados de Sequência Molecular , Polissacarídeos Bacterianos/metabolismo , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Infecções Estafilocócicas/microbiologia , Staphylococcus haemolyticus/classificação , Staphylococcus haemolyticus/genética , Staphylococcus haemolyticus/fisiologiaRESUMO
We analysed the antimicrobial susceptibility, biofilm formation and genotypic profiles of 27 isolates of Staphylococcus haemolyticus obtained from the blood of 19 patients admitted to a hospital in Rio de Janeiro, Brazil. Our analysis revealed a clinical significance of 36.8% and a multi-resistance rate of 92.6% among these isolates. All but one isolate carried the mecA gene. The staphylococcal cassette chromosome mec type I was the most prevalent mec element detected (67%). Nevertheless, the isolates showed clonal diversity based on pulsed-field gel electrophoresis analysis. The ability to form biofilms was detected in 66% of the isolates studied. Surprisingly, no icaAD genes were found among the biofilm-producing isolates.
Assuntos
Antibacterianos/uso terapêutico , Bacteriemia , Biofilmes/crescimento & desenvolvimento , Resistência Microbiana a Medicamentos/fisiologia , Staphylococcus haemolyticus , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bacteriemia/tratamento farmacológico , Bacteriemia/microbiologia , Criança , Pré-Escolar , Eletroforese em Gel de Campo Pulsado , Feminino , Genótipo , Humanos , Lactente , Recém-Nascido , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Fatores de Risco , Staphylococcus haemolyticus/efeitos dos fármacos , Staphylococcus haemolyticus/genética , Staphylococcus haemolyticus/fisiologia , Adulto JovemRESUMO
Antimicrobial sensitivity was evaluated from 120 strains of coagulase-negative Staphylococcus (CoNS), isolated from urinary infections. The isolated species were identified by conventional methods and sensitivity to vancomycin, tetracyclin, norfloxacin, cephalothin erythromycin, clindamycin, oxacillin, penicillin, cyprofloxacin, ampicillin and ampicillin/sulbactam was tested by the agar dilution technique and the diffusion in disc technique. The distribution of the species was: Staphylococcus epidermidis 26 (21.6%), S. haemolyticus 48 (40.0%), S. saprophyticus 40 (33.4%) and S. simulans 6 (5%). CoNS strains extracted from urinary infections showed a high percentage of vancomycin and tetracyclin sensitivity, and a low sensitivity to beta-lactamic antibiotics, except ampicillin/sulbactam and cephalotin. Isolation percentage resistance to oxacillin was less than 48%. Strains resistant to oxacillin were considered as resistant to both penicillin and ampicillin. From 42% to 80% of S. haemolyticus, S. saprophyticus, Staphylococcus epidermidis and S. simulans were positive to the adherence test. Results from this work showed that slime producing CoNS strains, isolated in Río Cuarto Hospital, had different percentages of resistance to the studied antimicrobial agents.