Clinical implications of icaA and icaD genes in coagulase negative staphylococci and Staphylococcus aureus bacteremia in febrile neutropenic pediatric cancer patients

Abstract

Background Staphylococci are the most frequently isolated organisms from blood cultures of febrile neutropenic (FN) cancer patients. We aimed to define the nature of these isolates by studying the prevalence of icaA and icaD genes in coagulase‐negative staphylococci (CoNS) and Staphylococcus aureus isolates in relation to clinical and microbiological features. Procedure Fifty‐five CoNS and S. aureus isolates from blood cultures of FN pediatric patients receiving chemotherapy were tested for slime production using Congo red agar plate test (CRA test), and for the presence of icaA and icaD genes by PCR. Results Of the CoNS isolates, eight were positive for ica genes, and three were slime positive/ica negative. A total of 11 (24.4%) cases of CoNS bacteremia were either ica genes or CRA test positive. There was a concordance between ica genes and CRA test positivity (P < 0.001). S. aureus isolates exhibited icaA and icaD genes more than CoNS isolates (P = 0.03). Vancomycin was significantly more prescribed in episodes of ica‐positive cases (P = 0.029). Conclusions The results of the present study support the hypothesis that the ica genes are important virulence markers for clinically significant CoNS isolates, indicating their ability to produce slime. This could be used to assign a group with higher risk FN. On the other hand, absence of these genes may permit, along with other clinical criteria, the consideration of a low‐risk FN episode and allow for safe early discharge. Pediatr Blood Cancer 2009;52:824–828. © 2009 Wiley‐Liss, Inc.

A comparative analysis of phenotypic and genotypic methods for the determination of the biofilm-forming abilities of Staphylococcus epidermidis

“…The majority of the ica-positive nasopharyngeal S. epidermidis isolates were also able to produce slime, which was monitored using the CRA test. This is in agreement with the data presented by other authors (Arciola et al, 2002;Stevens et al, 2008;El-Mahallawy et al, 2009); the presence of the ica operon was strongly associated with a slime-positive phenotype. However, ica-negative and slime-positive isolates in the CRA test were also described in the present paper.…”

“…MtP, CRA and/or PCR methods have been used by many researchers to determine the crucial virulence factors of CoNS, i.e. the ability of biofilm formation (Christensen et al, 1985;Freeman et al, 1989;Arciola et al, 2002Arciola et al, , 2006Bozkurt et al, 2009;El-Mahallawy et al, 2009). Some reports (Frebourg et al, 2000;Galdbart et al, 2000;Vandecasteele et al, 2003;Chokr et al, 2006;Satorres & Alcaráz, 2007;Mateo et al, 2008;Jain & Agarwal, 2009) indicate that these methods, alone or in combination, can be useful to discriminate between colonizing or commensal and invasive staphylococcal strains and can lead to the early detection and management of potentially pathogenic isolates responsible for device-associated nosocomial infections.…”

High biofilm production by invasive multiresistant staphylococci

“…Otherwise, all invasive strains were obtained from two consecutive paired blood cultures with a 3‐day‐interval, and presented high rates of biofilm production. Contrarily to other studies (9, 26, 27), 100% S. aureus were biofilm‐producers whereas 75.5% CoNS and 81.5% S. epidermidis , which originally were described as first slime‐producer species (28). Persistent staphylococci bacteremia, commonly defined as bacteremia sustained for 3 days or longer (29) may have biofilm‐forming staphylococci as an important risk factor for persistence, mainly when associated with foreign bodies.…”

Analysis of S. Epidermidis icaA and icaD genes by polymerase chain reaction and slime production: a case control study

“…In other evidences, the biofilm accumulation is mediated by certain genes, such as icaA, icaB, icaC, icaD and icaR [25,26]. The recent findings point to an important role of the icaA and icaD due to their ability to produce slime strongly in a high percentage of clinical isolates collected from patients with catheters associated infection [10]. Cafiso V reported that the co-expression of icaA with icaD can increase slime production remarkably [19].…”

“…Coagulase-negative staphylococci, particularly S epidermidis , are the important cause of infections associated with foreign materials. Bacterial adhesion has been considered as the leading cause of severe nosocomial infections related to implanted medical devices [10]. In the recent years, a study has been conducted to investigate the ica gene as a marker of the S. epidermidis adhesive aptitude [11].…”