Antimicrobial susceptibility profile and research of mec A and erm genes in coagulase-negative staphylococci isolated from platelet concentrates bags

Rosiéli Martini,Daniel Ângelo Sganzerla Graichen,Rosmari Hörner

doi:10.1590/s2175-97902017000115195

Rosiéli Martini, Daniel Ângelo Sganzerla Graichen + Show 1 more

Open Access

https://doi.org/10.1590/s2175-97902017000115195

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Abstract

In recent years, several studies have described the clinical impact of bacterial infection associated with transfusion of platelet concentrates (PCs). Among the blood components, PCs are responsible for the highest rates of bacterial contamination as well as septic transfusion reactions. We assessed antimicrobial susceptibility profile, resistance to methicillin (MRCoNS), and resistance to macrolides, lincosamides and streptogramins of group B (MLSB) of 16 coagulase-negative staphylococci (CoNS) isolates from an investigation in 691 PCs bags. We then compared conventional and automated phenotypic methods, disc diffusion test (DD) and VITEK(r) 2, respectively as well as phenotypic and genotypic methods (Polymerase Chain Reaction - PCR). All CoNS were susceptible to vancomycin. The disc diffusion test characterized 18.75% as MRCoNS and 37.5% with inducible resistance to MLSB (iMLSB), and with VITEK(r) 2, 6.3% and 31.25%, respectively. The mecA gene was detected in 18.75% and the erm gene in 31.25% of the isolates. In this study, we found equal percentage values between presence of the mecA gene by PCR and resistance to methicillin using cefoxitin by DD test, evidence of the erm gene by PCR, and iMLSB resistance by automation (VITEK(r) 2). Moreover, we identified three strains with beta-lactamase overproduction, and the occurrence of a bigger mistake was verified when automation was compared with DD test. And we observed that D-test was the most reliable for the detection of iMLSB resistance in Staphylococcus sp.

Highlights

Bacterial contamination of blood components has probably been the first disease transmitted by transfusion (Blajchman, 1995)
Antimicrobial susceptibility testing was performed using disk diffusion test (DD) following the cutoff points recommended by the Clinical and Laboratory Standards Institute (Clinical and Laboratory Standards Institute, 2014), and susceptibility testing was performed by VITEK® 2 automated method, according to the manufacturer’s standards
From the total of 16 isolates of coagulase-negative staphylococci (CoNS) obtained through a research on bacterial contamination carried out in 691 platelet concentrates (PCs) from HEMORGS/SM, five were identified as Staphylococcus haemolyticus (31.25%), four as Staphylococcus epidermidis (25%), four as Staphylococcus warneri (25%), and three as Staphylococcus saprophyticus (18.75%)

Summary

Introduction

Bacterial contamination of blood components has probably been the first disease transmitted by transfusion (Blajchman, 1995). Several measures have been deployed to prevent and detect bacterial contamination of platelet concentrates (PCs). These actions have reduced but not eliminated the risk of septic transfusion reactions (Eder, Goldman, 2011). PCs are blood components with the highest bacterial contamination rate and usually responsible for most of septic transfusion reactions (Chang et al, 2004). This type of bacterial contamination due to PCs infusion is much higher than other types of transfusion-transmitted infections (Jacobs, Palavecino, Yomtovian, 2001; Goodnough, Sander, Brecher, 2003; Vasconcelos et al, 2004)

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