RESUMO
INTRODUCTION:: Methicillin resistant Staphylococcus hominis (MRSHo) has been recognized as an important human pathogen, particularly in immunocompromised patients. METHODS:: A total of 19 S. hominis isolates were collected from children at the Children's Medical Centre, Tehran, Iran, from March 2012 to February 2013. MRSHo susceptibility against 13 antimicrobial and 3 antiseptic agents was determined using disk diffusion (DAD) and minimum inhibitory concentration (MIC), respectively. All isolates were subjected to polymerase chain reaction (PCR) assay for 15 distinct resistance genes, staphylococcal cassette chromosome mec (SCCmec), and arginine catabolic mobile elements (ACMEs). Biofilm production of the isolates was determined using a colorimetric microtiter plate assay. RESULTS:: Of the 19 isolates, 16 were resistant to oxacillin and harbored mecA. High resistance was also observed against trimethoprim/sulfamethoxazole (81.2%). All MRSHo isolates were susceptible to the three disinfectants tested (Septicidine-PC, Septi turbo, and Sayacept-HP). In total, 15 (78.9%) isolates produced biofilms. Three isolates had SCCmec types (V and VIII), 13 were untypable (UT), and 5 had ACME type II. CONCLUSIONS:: The results indicate that MRSHo with high antibiotic resistance and unknown SCCmec might become a serious problem in the future for the treatment of patients such as children.
Assuntos
Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Cromossomos Bacterianos/genética , Resistência a Meticilina/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus hominis/efeitos dos fármacos , Criança , DNA Bacteriano , Farmacorresistência Bacteriana , Humanos , Irã (Geográfico) , Testes de Sensibilidade Microbiana , Staphylococcus hominis/fisiologiaRESUMO
Abstract INTRODUCTION: Methicillin resistant Staphylococcus hominis (MRSHo) has been recognized as an important human pathogen, particularly in immunocompromised patients. METHODS: A total of 19 S. hominis isolates were collected from children at the Children's Medical Centre, Tehran, Iran, from March 2012 to February 2013. MRSHo susceptibility against 13 antimicrobial and 3 antiseptic agents was determined using disk diffusion (DAD) and minimum inhibitory concentration (MIC), respectively. All isolates were subjected to polymerase chain reaction (PCR) assay for 15 distinct resistance genes, staphylococcal cassette chromosome mec (SCCmec), and arginine catabolic mobile elements (ACMEs). Biofilm production of the isolates was determined using a colorimetric microtiter plate assay. RESULTS: Of the 19 isolates, 16 were resistant to oxacillin and harbored mecA. High resistance was also observed against trimethoprim/sulfamethoxazole (81.2%). All MRSHo isolates were susceptible to the three disinfectants tested (Septicidine-PC, Septi turbo, and Sayacept-HP). In total, 15 (78.9%) isolates produced biofilms. Three isolates had SCCmec types (V and VIII), 13 were untypable (UT), and 5 had ACME type II. CONCLUSIONS: The results indicate that MRSHo with high antibiotic resistance and unknown SCCmec might become a serious problem in the future for the treatment of patients such as children.
Assuntos
Humanos , Criança , Infecções Estafilocócicas/microbiologia , Resistência a Meticilina/genética , Cromossomos Bacterianos/genética , Biofilmes/crescimento & desenvolvimento , Staphylococcus hominis/efeitos dos fármacos , Antibacterianos/farmacologia , DNA Bacteriano , Testes de Sensibilidade Microbiana , Farmacorresistência Bacteriana , Staphylococcus hominis/fisiologia , Irã (Geográfico)RESUMO
In this work, the molecular and phenotypic antimicrobial resistance and clonal diversity of 10 linezolid-resistant Staphylococcus spp. isolates were investigated. The 7 Staphylococcus haemolyticus isolates presented Staphylococcal cassete chromosome mec (SCCmec) V and belonged to the same pulsed-field gel electrophoresis pulsotype. Their MICs for oxacillin, vancomycin, and linezolid were ≥ 256 µg/mL, 1-4 µg/mL, and 8-16 µg/mL, respectively. The 3 S. hominis presented MIC values 32 to >256 µg/mL, 2-4 µg/mL, and 12-24 µg/mL, and all carried the nontypeable SCCmec (ccr1 + mecA class) and belonged to 2 different genotypes. The cfr gene was not found, but the mutation G2603T was detected in S. haemolyticus and C2190T and G2603T in Staphylococcus hominis in 23S rRNA. This study demonstrates the spread of a linezolid-resistant S. haemolyticus genotype and, for the first time, describes the mutation C2190T among S. hominis isolates with a double mutation in Brazil.
Assuntos
Acetamidas/farmacologia , Farmacorresistência Bacteriana/genética , Mutação , Oxazolidinonas/farmacologia , RNA Ribossômico 23S/genética , Staphylococcus haemolyticus/genética , Staphylococcus hominis/genética , Antibacterianos/farmacologia , Brasil , Farmacorresistência Bacteriana/efeitos dos fármacos , Eletroforese em Gel de Campo Pulsado , Hospitais , Humanos , Linezolida , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/microbiologia , Staphylococcus haemolyticus/efeitos dos fármacos , Staphylococcus haemolyticus/isolamento & purificação , Staphylococcus hominis/efeitos dos fármacos , Staphylococcus hominis/isolamento & purificaçãoAssuntos
Acetamidas/farmacologia , Proteínas de Bactérias/metabolismo , Mutação , Oxazolidinonas/farmacologia , RNA Ribossômico 23S/metabolismo , Proteínas Ribossômicas/metabolismo , Staphylococcus hominis/efeitos dos fármacos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Brasil , Farmacorresistência Bacteriana Múltipla , Genes Bacterianos , Humanos , Unidades de Terapia Intensiva , Linezolida , Testes de Sensibilidade Microbiana , RNA Ribossômico 23S/genética , Proteínas Ribossômicas/genética , Ribossomos/genética , Ribossomos/metabolismo , Infecções Estafilocócicas/diagnóstico , Staphylococcus hominis/genética , Staphylococcus hominis/isolamento & purificação , Centros de Atenção TerciáriaRESUMO
Nasal carriage of methicillin-resistant coagulase-negative staphylococci (MR-CoNS) is highly prevalent in community subjects, but its dynamic has been little investigated. Nasal swabbing was performed in 2006 and 2008 in 154 Amerindians living isolated in French Guiana. MR-CoNS strains were identified and characterized by non-ß-lactam susceptibility testing and staphylococcal cassette chromosome mec element (SCCmec) typing, characterizing the associations of ccr and mec gene complex allotypes, and for MR Staphylococcus epidermidis (MRSE), multilocus variable number of tandem repeats analysis (MLVA) was used. The impact of sociodemographic and medical characteristics on the persistence of MR-CoNS carriage was assessed by bivariate analysis. Prevalence of MR-CoNS carriage was 50.6% in 2006 and 46.8% in 2008. The 274 MR-CoNS isolates, including S. epidermidis (n = 89, 62 MLVA patterns), Staphylococcus haemolyticus (n = 78), and Staphylococcus hominis (n = 72), exhibited 41 distinct ccr and mec gene complex associations. Persistent carriage (in 2006 and 2008), intermittent carriage (either in 2006 or 2008), and noncarriage were documented in 25.3, 47.4, and 27.3% of the participants, respectively. Persistent carriage of a given MRSE isolate was rarely observed (n = 8 isolates). Furthermore, no epidemiological factor, including antibiotic exposure, was associated with persistent carriage. The high diversity of MRSE clones and their ccr and mec gene complex associations contrasted with the high carriage rates in this isolated community, which might reflect the occurrence of SCCmec rearrangement and the generation of new MR-CoNS strains.
Assuntos
Coagulase/genética , Resistência a Meticilina/genética , Nariz/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus epidermidis/genética , Staphylococcus haemolyticus/genética , Staphylococcus hominis/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/administração & dosagem , Antibacterianos/uso terapêutico , Técnicas de Tipagem Bacteriana , Portador Sadio , Cromossomos Bacterianos , Coagulase/deficiência , Feminino , Guiana Francesa/epidemiologia , Genes Bacterianos , Ligação Genética , Variação Genética , Humanos , Masculino , Resistência a Meticilina/efeitos dos fármacos , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Prevalência , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologia , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/isolamento & purificação , Staphylococcus haemolyticus/efeitos dos fármacos , Staphylococcus haemolyticus/isolamento & purificação , Staphylococcus hominis/efeitos dos fármacos , Staphylococcus hominis/isolamento & purificaçãoRESUMO
OBJECTIVES: To report the isolation of six Staphylococcus hominis subsp. novobiosepticus (SHN) strains from hospitalized patients with bloodstream infections in two Brazilian hospitals and to characterize their susceptibility profile to several antimicrobials. METHODS: Species identification was performed by biochemical methods and sodA gene sequencing. The MICs of antimicrobials were determined by broth and agar dilution methods and by Etest. Isolates were typed by PFGE and PCR amplification was used to detect the ccr gene complex and the mec class. Morphometric evaluation of cell wall was performed by transmission electron microscopy (TEM). RESULTS: Susceptibility profiles indicated that the majority of isolates (five) were multidrug-resistant. Overlapping and multiplex PCR showed that five out of the six strains harboured SCCmec type III with class A mec and type 3 ccr. The initial vancomycin MIC value of 4 mg/L for these strains increased to 16-32 mg/L after growth for 10 days in BHI broth supplemented with this antimicrobial. TEM indicated that vancomycin resistance was associated with cell wall thickening and to another mechanism not fully elucidated. Only one SHN strain was oxacillin- and vancomycin-susceptible. The nosocomial infections in at least five of the patients from both hospitals were caused by a single clone of SHN. CONCLUSIONS: It is very important to consider SHN strains as the cause of nosocomial infections. The clinical implications resulting from the pattern of multidrug resistance in these strains may be complicated by the emergence of vancomycin resistance.