Assessment of different methods for the detection of biofilm production in coagulase-negative staphylococci isolated from blood cultures of newborns

Abstract INTRODUCTION: Coagulase-negative staphylococci (CoNS) are a frequent cause of bacteremia, especially in neonates. The major virulence determinant in CoNS is the ability to produce biofilms, which is conferred by the icaADBC genes. This study aimed to assess different methods for the detecti...

Full description

Bibliographic Details
Published in:Revista da Sociedade Brasileira de Medicina Tropical
Main Authors: Roberta Filipini Rampelotto, Vinicius Victor Lorenzoni, Danielly da Costa Silva, Silvana Silveira Coelho, Vanessa Wust, Litiérri Razia Garzon, Melise Silveira Nunes, Bettina Meneghetti, Patrícia Chaves Brites, Manfredo Hörner, Rosmari Hörner
Format: Article in Journal/Newspaper
Language:English
Published: Sociedade Brasileira de Medicina Tropical (SBMT)
Subjects:
Biofilm
Blood culture
Coagulase-negative staphylococci
Newborn
Arctic medicine. Tropical medicine
RC955-962
Arctic
Online Access:https://doi.org/10.1590/0037-8682-0171-2018
https://doaj.org/article/09da245bfc484e48a73594e33ce4a768
Description
Summary:Abstract INTRODUCTION: Coagulase-negative staphylococci (CoNS) are a frequent cause of bacteremia, especially in neonates. The major virulence determinant in CoNS is the ability to produce biofilms, which is conferred by the icaADBC genes. This study aimed to assess different methods for the detection of biofilm formation in 176 CoNS isolates from blood cultures of newborns. METHODS: The presence of the icaACD genes was assessed by polymerase chain reaction (PCR), and biofilm formation was assessed on congo red agar (CRA), by the tube method (TM), and on tissue culture plates (TCP). RESULTS: Of the 176 CoNS isolates, 30.1% expressed icaACD and 11.4% expressed icaAD. The CRA assay and TM showed that 42% and 38.6% of the isolates were biofilm producing, respectively. On TCP, 40.9% of the isolates produced biofilms; 21% were weakly adherent and 19.9% were strongly adherent. When compared to the gold standard technique (PCR), the CRAassay showed 79% sensitivity and 84% specificity (kappa = 0.64), TM showed 78% sensitivity and 89% specificity (kappa = 0.68), and TCP showed 99% sensitivity and 100% specificity (kappa = 0.99). CONCLUSIONS: In this study, ~42% of CoNS isolates produced biofilms, and the presence of icaACD was associated with a greater capacity to form biofilms. Compared to the other phenotypic methodologies, TCP is an ideal procedure for routine laboratory use.

Similar Items