Letícia Eichstaedt Mayer

Oxacillin-resistant coagulase-negative Staphylococci bacteremia at a teaching hospital in Santa Maria, State of Rio Grande do Sul, Brazil

INTRODUCTION This study aimed to characterize the prevalence and susceptibility profile to oxacillin-resistant Coagulase-negative Staphylococci strains isolated from blood cultures in a teaching hospital, located in Santa Maria, RS. In addition, different methodologies for phenotypic characterization of mecA-mediated oxacillin resistance were compared with genotypic reference testing. METHODS After identification (MicroScan - Siemens), the isolates were tested for antimicrobial sensitivity using disk diffusion and automation (MicroScan - Siemens). The presence of mecA gene was identified by the polymerase chain reaction molecular technique. RESULTS The most common species was Staphylococcus epidermidis (n=40, 67%). The mecA gene was detected in 54 (90%) strains, while analysis of the sensitivity profiles revealed a high rate of resistance to multiple classes of antimicrobial drugs. However, all isolates were uniformly sensitive to vancomycin and tigecycline. The cefoxitin disk was the phenotypic method that best correlated with the gold standard. CONCLUSIONS Analysis of the clinical significance of CoNS isolated from hemocultures and the precise detection of oxacillin resistance represent decisive factors for the correct choice of antibiotic therapy. Although vancomycin constitutes the normal treatment in most Brazilian hospitals, reduction in its use is recommended.

Spontaneous bacterial peritonitis caused by Streptococcus bovis: case report and review of the literature

Spontaneous bacterial peritonitis (SBP) is a frequent and severe complication that occurs in patient with cirrhosis and ascites. It occurs in 10% to 30% of patients admitted to hospital. The organisms that cause SBP are predominantly enteric. Escherichia coli is the most frequent recovered pathogen, and Gram-positive bacteria, mainly Staphylococcus spp., are being considered an emerging causative agent of SBP. Streptococcus bovis that may be found as part of the commensal bowel flora in about 10% of healthy adults constitute an uncommon cause of peritonitis that was first reported in 1994. We describe the first case of SBP at the University Hospital of Santa Maria (HUSM) caused by S. bovis, resistant to the antibiotics erythromycin and clindamycin (inducible clindamycin resistance detected by disk diffusion test using the D-zone test).

PREVALÊNCIA E PERFIL DE SENSIBILIDADE DE Staphylococcus aureus ISOLADOS EM UM HOSPITAL ESCOLA NA CIDADE DE SANTA MARIA, BRASIL

Objetivou-se caracterizar a prevalencia e o perfil de suscetibilidade de Staphylococcus aureus isolados no Hospital Universitario de Santa Maria (HUSM), atraves de levantamento de dados junto ao Laboratorio de Analises Clinicas, durante o periodo de abril a junho de 2009. Foram solicitadas 3270 culturas, sendo que 1123 (34%) resultaram positivas. A prevalencia de S. aureus em relacao as culturas positivas foi de 89 (7,93%). Verificou-se que 33% das cepas foram resistentes a oxacilina e que 34,45% apresentaram resistencia relacionada ao gene erm. Elevada sensibilidade ao sulfametoxazol-trimetoprima (72/80%) foi evidenciada pela automacao e nenhuma cepa mostrou-se resistente a vancomicina. Portanto, a prevalencia de S. aureus no HUSM e a resistencia a oxacilina foram inferiores ao observado em outros hospitais terciarios brasileiros. The objective ofthis study was to characterize the prevalence and susceptibility prof ile ofStaphylococcus aureus isolates at University Hospital ofSantaMaria, through data collection at the Laboratory ofClinicalAnalysis, duringApril to June 2009. Were requested 3270 cultures and 1123 (34%) were positive. The prevalence of S. aureus in relation to positive cultures was 89 (7,93%). It was f ound that these strains, 33% were resistant to oxacillin and 34.45% showed resistance related erm gene. High sensitivity to trimethoprim-sulf amethoxazole (72/80%) was detected f or the automation and no strain showed resistance to vancomycin. Theref ore, the prevalence of S. aureus and oxacillin resistance at HUSM were lower than observed in other tertiary hospitals in Brazil. Descritors: Prevalence; Staphylococcus aureus; Bacterial inf ection, Oxacillin.

Evaluation of bacterial growth inhibition by mercaptopropionic acid in metallo-β-lactamase detection on multidrug-resistant Acinetobacter baumannii

INTRODUCTION Metallo-β-lactamase (MBL) has been reported all over the world. METHODS The inhibitory effect of mercaptopropionic acid (MPA) on bacterial growth was evaluated by comparison between disk diffusion and broth dilution methodology with determination of the minimum inhibitory concentration (MIC) for multidrug-resistant Acinetobacter baumanni strains. RESULTS MPA significantly inhibited growth of the strains. CONCLUSIONS The use of MPA can affect the results in phenotypic methods of MBL detection.

AVALIAÇÃO DA PREVALÊNCIA E DO PERFIL DE SENSIBILIDADE DE STAPHYLOCOCCUS COAGULASE NEGATIVA RESISTENTES À METICILINA/OXACILINA NO HOSPITAL UNIVERSITÁRIO DE SANTA MARIA (HUSM) E COMPARAÇÃO DE TESTES PARA DETECÇÃO DE RESISTÊNCIA

Os estafilococos coagulase negativa (ECN) tem sua patogenicidade cada vez mais reconhecida. Alem das infeccoes relacionadas aos dispositivos implantados, participam como agentes etiologicos em diversas infeccoes. A emergencia de cepas resistentes a meticilina/oxacilina reduz as opcoes terapeuticas, pois sao resistentes a todos os â-lactâmicos e as combinacoes de â-lactâmicos/inibidores de â-lactamase. Nesse contexto, diversos metodos tem sido empregados para a deteccao da resistencia a meticilina/oxacilina em ECN. No presente estudo avaliou-se 50 isolados de ECN resistentes a oxacilina. Staphylococcus epidermidis foi a especie mais isolada 30 (60%), sendo o sangue o especime clinico prevalente 19(38%) e a pediatria a unidade com o maior percentual de isolamentos 14 (28%). Estas cepas apresentaram elevado perfil de resistencia sendo que 62% delas mostraram-se sensiveis apenas a vancomicina, teicoplanina e tigeciclina. O metodo “screening” com agar oxacilina detectou a resistencia em todos isolados. Os discos de oxacilina 1 ig e cefoxitina 30 ig nao detectaram somente em dois isolados cada. Palavras-chave: estafilococos coagulase negativa; resistencia oxacilina/meticilina; deteccao de resistencia