Occurrence of the vanA gene in Staphylococcus epidermidis from nasopharyngeal secretion of Health-Care Workers, Recife, Brazil

Abstract INTRODUCTION: The increasing reports of vancomycin-resistant Staphylococcus strains (VRS) haves caused concern worldwide, from the laboratory detection to patient management. This study aimed to identify the occurrence of VRS strains among healthcare professionals from a university hospital. METHODS: A total of 102 Staphylococcus sp. isolates from healthcare professionals, obtained in a previous study were evaluated according to standard techniques for VRS detection. RESULTS: After screening inoculation of plates containing 6µg/ml of vancomycin, 19 resistant isolates were identified. The susceptibility profile to other antimicrobials revealed 18 multidrug resistant isolates. The minimum inhibitory concentration (MIC) was determined by E-test and broth microdilution. According to E-tests, of 19 isolates grown in BHI-V6, four isolates presented MIC ≥ 128 µg/ml, seven with MIC ranging from 4 to 8 µg/ml, and eight with MIC ≤ 2µg/ml. By broth microdilution, 14 isolates presented MIC ≤ 2 µg/ml and five with MIC ≥ 16µg/ml. The presence of the gene vanA was determined by PCR in the five resistant isolates, and this gene was detected in one of the strains. Furthermore, among the 19 strains, the gene mecA was found in 13 (39,4%) isolates, including the strain carrying the gene vanA. CONCLUSIONS: Based on these results, we highlight the presence of one strain carrying both vanA and the mecA genes, as well as multidrug-resistant strains colonizing healthcare professionals, and their importance as potential vectors to spread strains carrying resistance genes in the hospital environment.

The occurrence and dissemination of methicillin and vancomycin-resistant Staphylococcus in samples from patients and health professionals of a university hospital in Recife, State of Pernambuco, Brazil

Introduction Methicillin-resistant Staphylococcus aureus (MRSA) strains have been responsible for many nosocomial outbreaks. Within hospitals, colonized employees often act as reservoirs for the spread of this organism. This study collected clinical samples of 91 patients admitted to the intensive care unit (ICU), hemodialysis/nephrology service and surgical clinic, and biological samples from the nasal cavities of 120 professionals working in those environments, of a University Hospital in Recife, in the State of Pernambuco, Brazil. The main objective of this study was to determine the occurrence and dissemination of methicillin- and vancomycin-resistant Staphylococcus spp. Methods The isolates obtained were tested for susceptibility to oxacillin and vancomycin and detection of the mecA gene. In addition, the isolates were evaluated for the presence of clones by ribotyping-polymerase chain reaction (PCR). Results MRSA occurrence, as detected by the presence of the mecA gene, was more prevalent among nursing technicians; 48.1% (13/27) and 40.7% (11/27) of the isolates were from health professionals of the surgical clinic. In patients, the most frequent occurrence of mecA-positive isolates was among the samples from catheter tips (33.3%; 3/9), obtained mostly from the hemodialysis/nephrology service. Eight vancomycin-resistant strains were found among the MRSA isolates through vancomycin screening. Based on the amplification patterns, 17 ribotypes were identified, with some distributed between patients and professionals. Conclusions Despite the great diversity of clones, which makes it difficult to trace the source of the infection, knowledge of the molecular and phenotypic profiles of Staphylococcus samples can contribute towards guiding therapeutic approaches in the treatment and control of nosocomial infections. .

Phenotypic methods for determination of methicillin resistance in Staphylococcus spp. from health care workers / Métodos fenotípicos para determinação da resistência à meticilina em Staphylococcus spp. de profissionais de saúde

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.

INTRODUÇÃO: Staphylococcus spp. é um importante patógeno associado aos cuidados em saúde, e a identificação de isolados resistentes à meticilina em amostras de colonização pode fornecer dados para auxiliar no sucesso da terapia antimicrobiana. OBJETIVOS: Determinar a ocorrência de colonização por Staphylococcus spp. resistentes à meticilina (MRS) por meio da detecção do gene mecA e avaliar diferentes métodos fenotípicos para a detecção presuntiva da resistência à meticilina em amostras da cavidade nasal anterior e das mãos de profissionais de saúde de um hospital universitário no Estado de Pernambuco, Brasil. MÉTODOS: Foram selecionados 28 isolados de Staphylococcus spp. que mostraram perfil intermediário ou resistente à oxacilina, detectado pela técnica de Kirby Bauer. Os métodos utilizados foram o teste de disco difusão de cefoxitina, concentração inibitória mínima pelo E-test de oxacilina, screening para avaliação da resistência à oxacilina e reação em cadeia da polimerase (PCR) para detecção do gene mecA. RESULTADOS: Dos métodos fenotípicos utilizados, apenas o E-test de oxacilina não mostrou diferença estatística significante em relação à PCR para a detecção do gene mecA, considerado o método padrão-ouro. CONCLUSÃO: O E-test de oxacilina foi o melhor método fenotípico utilizado. É necessário detectar corretamente o MRS em indivíduos saudáveis, pois eles podem atuar como portadores, sendo uma fonte potencial de microrganismos envolvidos em infecções hospitalares.

Colonização pelo Staphylococcus aureus em profissionais de enfermagem de um hospital escola de Pernambuco / Colonization by Staphylococcus aureus among the nursing staff of a teaching hospital in Pernambuco / Colonización por Staphylococcus aureus en profesionales de enfermería de un hospital escuela de Pernambuco

O presente estudo foi realizado com o objetivo de identificar a prevalência de colonização pelo Staphylococcus aureus em profissionais de enfermagem de um hospital universitário de Pernambuco, bem como avaliar o perfil de resistência deles isoladamente. Para isso, foi realizado um estudo transversal, no qual foram coletadas amostras biológicas das mãos e da cavidade nasal. A identificação do S. aureus foi realizada por meio do semeio em agar-sangue, agar manitol-salgado e através dos testes de catalase e coagulase. O perfil de sensibilidade foi determinado pela técnica de Kirby Bauer e para determinação da resistência à meticilina foi realizado o screening em placa com oxacilina com adição de 4% de NaCl. Dos 151 profissionais avaliados, 39 se encontravam colonizados, o que demonstrou uma prevalência de 25,8%. Dentre as variáveis estudadas, a faixa etária e a quantidade de EPI apresentaram-se associadas à colonização pelo microrganismo. De todas as linhagens isoladas, apenas cinco apresentaram resistência à meticilina.

This study was performed with the objective to identify the prevalence of colonization by Staphylococcus aureus in nursing professionals from a teaching hospital in Pernambuco, and evaluate the resistance profile of these isolates. To do this, we performed a cross-sectional study where biological samples were collected from the hands and nasal cavities of the subjects. S. aureus was identified using agar (blood agar and mannitol salt) via catalase and coagulase tests. The sensitivity profile was determined by Kirby Bauer technique and determination of methicillin resistance was performed with oxacillin screening with sodium chloride (NaCl) addition. Of the 151 professionals evaluated, 39 were colonized which showed a prevalence of 25.8%. Among the variables studied, age and use of PPE were associated with colonization by the organism. Of all the isolates, only five were resistant to methicillin.

Estudio realizado para identificar prevalencia de colonización por Staphylococcus aureus en profesionales de enfermería de hospital universitario de Pernambuco, así como evaluar el perfil de resistencia de la bacteria aislada. Se realizó un estudio transversal en el que se recolectaron muestras biológicas de manos y cavidad nasal. La identificación del S. aureus se realizó mediante cultivo en agar-sangre, agar-manitol salado y mediante pruebas de catalasa y coagulasa. El perfil de sensibilidad se determinó por técnica de Kirby Bauer y para la determinación de resistencia a meticilina se realizó screening en placa con oxalacina, con adición de 4% de NaCl. De 150 profesionales evaluados, 39 estaban colonizados, lo que demostró prevalencia de 25,8%. Entre las variables estudiadas, faja etaria y cantidad de EPI se presentaron asociadas con la colonización por la bacteria. De todas las cepas aisladas, apenas cinco presentaron resistencia a meticilina.

Staphylococcus aureus: aspectos biológicos e patogênicos / Staphylococcus aureus: biological and pathogenic aspects

Na atualidade o gênero Staphylococcus abrange aproximadamente 42 espécies, sendo que destas, 20 são de interesse médico e veterinário, uma vez que, estão associadas a uma variedade de infecções oportunistas em seres humanos e animais. Dentre essas espécies causadoras de enfermidades, o Staphylococcus aureus requer especial atenção devido a seu alto potencial patogênico e também a sua capacidade de desenvolver resistência aos antimicrobianos utilizados rotineiramente na prática clínica, estando desta forma, associado a um amplo espectro de doenças que variam desde lesões cutâneas superficiais até infecções sistêmicas graves.