Adhesive properties and antibiotic resistance of Klebsiella, Enterobacter, and Serratia clinical isolates involved in nosocomial infections

Abstract

Intestinal colonization by Klebsiella, Enterobacter, and Serratia (KES) strains is a crucial step in the development of nosocomial infections. We studied the adhesive properties, antibiotic resistance, and involvement in colonization or infection of 103 KES clinical isolates: 30 Klebsiella pneumoniae (29%), 16 Klebsiella oxytoca (15%), 30 Enterobacter aerogenes (29%), 14 Enterobacter cloacae (14%), and 13 Serratia sp. (13%) isolates. Half of them were resistant to several antimicrobial agents, including aminoglycosides and ␤-lactam antibiotics. A total of 27 of 30 K. pneumoniae isolates (90%) adhered to the human cell line Intestine-407 (Int-407), while none of the K. oxytoca or E. aerogenes isolates and only 2 of the E. cloacae isolates adhered. Three adhesive patterns were observed for K. pneumoniae: an aggregative adhesion in 57% of the isolates, a diffuse adhesion in only one isolate, and a new pattern, localized adhesion, in 30% of the isolates. While most of the sensitive strains adhered with the aggregative phenotype, the localized pattern was associated with resistant K. pneumoniae isolates producing the CAZ-5 ␤-lactamase. Furthermore, 45% of such localized-adhesion isolates were involved in severe infections. The distributions of type 1 and type 3 fimbriae, enteroaggregative E. coli, and cf29, pap, and afa/Dr adhesin-encoding genes were determined by using specific DNA probes. No relationship was found between the adhesive pattern and the production of specific fimbriae, suggesting that several unrecognized adhesive factors are involved. Our study indicates that special adhesive properties associated with resistance to antimicrobial agents could account for the pathogenicity of certain nosocomial strains.

Evaluation of biofilm formation of Klebsiella pneumoniae isolated from medical devices at the University Hospital of Tlemcen, Algeria

“…Other studies demonstrated the influence of capsule and extended-spectrum beta-lactamase encoding plasmids upon K. pneumoniae adhesion (Hennequin and Forestier, 2007). A high prevalence of type 1 and type 3 pili has been previously observed in clinical and environmental K. pneumoniae isolates (Livrelli et al, 1996;Martynenko et al, 1992;Podschun et al, 2001;Schurtz et al, 1994). Type 3 pili, mostly found in K.…”

Pathogenic potential of environmental Klebsiella pneumoniae isolates

“…It is likely that the strains in which the fimbrial genes were detected but where fimbrial expression was not seen are able to express the fimbriae but do not do so under the conditions applied in this study. Several studies have examined the frequency of type 1 and type 3 fimbriae expression in populations of K. pneumoniae strains including strains isolated from the environment (Podschun et al ., 1987;1993;Hornick et al ., 1991;Podschun and Sahly, 1991;Tarkkanen et al ., 1992;Livrelli et al ., 1996). In all studies, the vast majority of strains were found to possess type 1 as well as type 3 fimbriae.…”

“…Detection of genes encoding type 1 or type 3 fimbriae was performed by dot-blotting using radiolabelled DNA probes as described previously (Livrelli et al, 1996).…”

Pseudomonas aeruginosa isolates recovered from clinical and environmental samples in Buea, Cameroon: current status on biotyping and antibiogram

“…1993). P. aeruginosa accounts for a significant proportion of nosocomial infections and the tendency of nosocomial pathogens to develop or acquire new antibiotic resistance traits poses a great problem in their treatment and control (Livrelli et al. 1996).…”