Voltar
Artigo Acesso aberto Produção Nacional Revisado por pares
BIBTEX RIS

Methicillin-resistant Staphylococcus epidermidis isolates with reduced vancomycin susceptibility from bloodstream infections in a neonatal intensive care unit

2019; Microbiology Society; Volume: 69; Issue: 1 Linguagem: Inglês

10.1099/jmm.0.001117

ISSN

1473-5644

Autores

Patrícia Borges Peixoto, Fernando Henrique Massinhani, Kátia Regina Netto dos Santos, Raiane Cardoso Chamon, Renata Beatriz Silva, Fábio Ederson Lopes Corrêa, Cristina da Cunha Hueb Barata de Oliveira, Adriana Gonçalves de Oliveira,

Tópico(s)

Bacterial biofilms and quorum sensing

Resumo

Introduction. Vancomycin has become the first-line therapy for most infections caused by methicillin-resistant staphylococci.Aim. To evaluate the vancomycin MIC, staphylococcal cassette chromosome mec (SCCmec) types and clonality of coagulase-negative staphylococci (CoNS) isolates recovered from neonates with true primary bloodstream infections (BSI).Methodology. CoNS isolates were prospectively recovered from blood cultures of non-repetitive patients admitted to a neonatal intensive care unit (NICU) in a tertiary-care hospital during a 3-year period. BSI was defined based on established criteria. Micro-organisms were identified phenotypically and by PCR. MIC-values for vancomycin and oxacillin were determined by broth dilution method and E-test. The SCCmec type conferring methicillin resistance was determined by multiplex PCR. The heterogeneous vancomycin (hV) resistance phenotype was screened on brain heart infusion agar containing 4 µg ml-1 of vancomycin. The clonality was investigated by PFGE.Results. Seventy-four CoNS isolates were recovered from blood cultures of neonates during the study period but only 40 (54 %) were associated with true primary BSI. Nine (22.5%) babies died. Staphylococcus epidermidis was the most prevalent species (95 %; 38/40). All S. epidermidis isolates were methicillin-resistant (MR). SCCmec type IV was predominant (55.3 %; 21/38). Most (80.0 %; 32/38) isolates exhibited vancomycin MIC-values of 2-4 µg ml-1 not associated with the SCCmec type or clonality. Sixteen (42.1%) isolates displayed hV resistance. All babies who died were harbouring MR-S. epidermidis exhibiting vancomycin MICs of 2-4 µg ml-1.Conclusion. The findings of this study demonstrated that blood invasive MR-S. epidermidis isolates recovered at NICU tend to show decreased vancomycin susceptibility making therapy of those fragile patients difficult.

Referência(s)