Molecular analysis of Panton-Valentine Leucocidin (pvl) gene among MRSA and MSSA isolates / Análise molecular do gene Panton-Valentine Leucocidin (pvl) entre isolados de MRSA e MSSA

The present study was conducted in order to determine the frequency of pvl gene among the pathogenic and healthy population isolates of Methicillin Resistant Staphylococcus aureus (MRSA) and Methicillin Sensitive Staphylococcus aureus (MSSA). For this purpose, nasal swab samples were collected from the healthy individuals (to be used as controls, all the samples were collected irrespective of the sex and age factors), the pathogenic samples were collected from different patients suffering from skin &soft tissue infections caused by S. aureus (to be used as test samples).Both of these population samples were analyzed for the presence of pvl gene. S.aureus were identified through conventional microbiological identification procedures. In the case of normal samples, 70 nasal swabs were collected and only 33 (47%) proved to be S. aureus while 20 pathogenic samples were collected and all (100%) were cleared as S. aureus. For further distribution of samples into MRSA and MSSA, antibiotic susceptibility pattern was checked by using the standard protocols of Kirby-Bauer disc diffusion method. Two antibiotic discs Oxacillin (OX: 1ug) and cefoxitin (FOX: 30ug) were used. Among healthy population, MRSA was found to be 79% (n=26) and MSSA were present as 21% (n= 7). Among pathogenic strains 100% MRSA was detected where n= 20. Detection of pvl gene among the MRSA and MSSA isolates was done by using the uniplex PCR followed by gel electrophoresis. MRSA and MSSA of normal healthy population carried 49% and 7% pvl gene respectively. While, pathogenic MRSA samples carried 46% pvl gene among them. Potentially alarming percentage of pvl gene is present among the normal healthy individuals which indicates a future threat and a major health concern.

O presente estudo almejou determinar a frequência do gene PVL entre os isolados patogênicos e saudáveis da população de Staphylococcus aureus resistente à meticilina (MRSA) e Staphylococcus aureus sensível à meticilina (MSSA). Para este propósito, amostras de swab nasal foram coletadas de indivíduos saudáveis (utilizadas como controle, todas as amostras foram coletadas independentemente do sexo e idade), e de diferentes pacientes com infecções de pele e tecidos moles causadas por S. aureus (utilizadas como amostras de teste). Ambas as amostras populacionais foram analisadas quanto à presença do gene PVL. S.aureus foram identificados através de procedimentos convencionais de identificação microbiológica. No caso de amostras normais, 70 swabs nasais foram coletados e apenas 33 (47%) provaram ser S. aureus, enquanto 20 amostras patogênicas foram coletadas e todas (100%) foram eliminadas como S. aureus. Para distribuição posterior de amostras em MRSA e MSSA, o padrão de suscetibilidade a antibióticos foi verificado a partir dos protocolos padrão do método de difusão de disco de Kirby-Bauer. Foram utilizados dois discos de antibióticos Oxacilina (OX: 1ug) e cefoxitina (FOX: 30ug). Entre a população saudável, MRSA foi encontrado em 79% (n = 26) e MSSA estava presente em 21% (n = 7). Entre as cepas patogênicas, 100% de MRSA foi detectado onde n = 20. A detecção do gene PVL entre os isolados de MRSA e MSSA foi feita usando a PCR uniplex seguida de eletroforese em gel. MRSA e MSSA da população saudável normal carregavam 49% e 7% do gene PVL, respectivamente. Enquanto as amostras patogênicas de MRSA carregavam 46% do gene PVL entre elas. Uma porcentagem potencialmente alarmante do gene PVL foi detectada entre os indivíduos saudáveis normais, o que indica uma ameaça futura e um grande problema de saúde.

Community-associated methicillin-resistant Staphylococcus aureus in non-outbreak skin infections

The aim of this study was to determine the prevalence of Staphylococcus aureus and risk factors for the acquisition of MRSA (Methicillin Resistant Staphylococcus aureus) as the main cause of skin and soft tissue infections. S. aureus were characterized for the presence of PVL, TSST-1 and mecA genes. SCCmec typing was carried out in mecA positive strains and PFGE was performed only in these strains. During the study period, 127 outpatients attending a dermatology clinical the Botucatu Medical School, a regional tertiary hospital in Botucatu, Sao Paulo, Brazil, were diagnosed with active skin infections. A total 66 (56.9%) S. aureus strains were isolated. The methicillin resistance gene mecA was detected in seven (10.6%) S. aureus strains. The SCCmec types detected in the seven mecA-positive S. aureus strains were type Ia in one, type II in three, and type IV in three. The PVL gene was detected in 10 (15.1%) in sensitive strains. Pulsed field gel electrophoresis revealed non-clonal diversity among the isolates. The risk factors associated with MRSA acquisition in this study were previous ciprofloxacin use and working in a healthcare environment. The risk factors indicate plausible routes of CA-MRSA transmission among the subjects studied.