BACKGROUND: Coagulase-negative staphylococci (CoNS) may cause serious infections in immunocompromized patients. CoNS often display multiresistance to antibiotics, and biofilm production is the central virulence factor. Our aim was to investigate these factors in CoNS that colonize children with an increased risk of CoNS infections. MATERIAL AND METHOD: We collected CoNS isolates from intravasal catheters (n = 19) and the skin (n = 47) from 30 hospitalized neonates, and CoNS skin isolates from 20 children with cancer before (n = 20) and after (n = 18) six months of cancer treatment. We analyzed antibiotic resistance and biofilm production with phenotypic methods. We used PCR to detect genes that encode antibiotic resistance and biofilm formation. RESULTS: 11 of 19 (58 %) catheter isolates and 14 of 47 (30 %) skin isolates (p = 0.04) produced biofilm. We found an increasing prevalence of oxacillin resistance (20 % versus 67 %, p = 0.004) and gentamicin resistance (15 % versus 67 %, p = 0.003) after six months of cancer treatment. Biofilm positive CoNS isolates displayed higher levels of antibiotic resistance than biofilm-negative isolates. INTERPRETATION: Our results indicate that sick neonates and children hospitalized with cancer are colonized with pathogenic CoNS strains demonstrating virulence- and antibiotic-resistance patterns that are different from those found in CoNS in healthy people who are not hospitalized.
BACKGROUND: Coagulase-negative staphylococci (CoNS) may cause serious infections in immunocompromized patients. CoNS often display multiresistance to antibiotics, and biofilm production is the central virulence factor. Our aim was to investigate these factors in CoNS that colonize children with an increased risk of CoNS infections. MATERIAL AND METHOD: We collected CoNS isolates from intravasal catheters (n = 19) and the skin (n = 47) from 30 hospitalized neonates, and CoNS skin isolates from 20 children with cancer before (n = 20) and after (n = 18) six months of cancer treatment. We analyzed antibiotic resistance and biofilm production with phenotypic methods. We used PCR to detect genes that encode antibiotic resistance and biofilm formation. RESULTS: 11 of 19 (58 %) catheter isolates and 14 of 47 (30 %) skin isolates (p = 0.04) produced biofilm. We found an increasing prevalence of oxacillin resistance (20 % versus 67 %, p = 0.004) and gentamicin resistance (15 % versus 67 %, p = 0.003) after six months of cancer treatment. Biofilm positive CoNS isolates displayed higher levels of antibiotic resistance than biofilm-negative isolates. INTERPRETATION: Our results indicate that sick neonates and children hospitalized with cancer are colonized with pathogenic CoNS strains demonstrating virulence- and antibiotic-resistance patterns that are different from those found in CoNS in healthy people who are not hospitalized.