Fabiane Rigatti

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).

Contaminação bacteriana em concentrados plaquetários: identificação, perfil de sensibilidade aos antimicrobianos e sepse associada à transfusão

INTRODUCTION Bacterial sepsis associated with the transfusion of platelet concentrates (PCs) results in serious clinical implications for patients. Given these implications, certain procedures have been integrated into the preparation and quality control of blood components to reduce the risk of bacterial contamination. This article describes the prevalence of bacterial contamination on transfused PCs, the bacterial spectrum detected and their antimicrobial susceptibility profile and transfusion reactions in receptors. METHODS A total of 292 PCs (278 random and 14 per apheresis) from the Blood Center of the State of Rio Grande do Sul (HEMORGS), located in the city of Santa Maria, were tested. Quantities of 100 μL and 200 μL were collected from platelet bag tubing and seeded using two methodologies. RESULTS Using the qualitative methodology, bacteria were isolated in five units (1.7%; 5/292), while only one was isolated using the quantitative methodology. Staphylococcus epidermidis was the microorganism identified in all samples. Two patients died of transfusion-related sepsis. CONCLUSIONS Bacterial contamination due to PC transfusion is considered a major public health problem due to its association with high rates of morbidity and mortality. In this study only gram-positive microorganisms were isolated and none of the samples obtained by apheresis presented contamination.