RELATIONSHIP BETWEEN ADHESION TO INTESTINAL CACO-2 CELLS AND MULTIDRUG-RESISTANCE IN KLEBSIELLA-PNEUMONIAE CLINICAL ISOLATES

Klebsiella pneumoniae is an opportunistic gram-negative pathogen invol ved in outbreaks of nosocomial infections in intensive care units. Str ains are resistant to multiple antibiotics, and 15 to 30% of them are also resistant to the broad-spectrum cephalosporins by the production of R plasmid-encoded extended-spectrum beta-lactamases. Because the ga strointestinal tracts of patients have been shown to be the reservoir for nosocomial strains of K. pneumoniae, we looked for a correlation b etween antibiotic resistance and adhesion of K. pneumoniae strains to intestinal cells. We investigated adhesion to the human intestinal epi thelial Caco-2 cell line of 61 clinical K. pneumoniae strains isolated in hospitals in Clermont-Ferrand, France. None of the strains tested expressed the previously described adhesive factors CF29K and KPF-28. Adhesive properties were found for 42.6% of the strains tested (26 str ains). Just 7.7% (2 strains) of the 26 strains producing only the chro mosomally encoded SHV-1 beta-lactamase adhered to the Caco-2 cell line , whereas 68.5% (24 strains) of the 35 strains producing a plasmid-enc oded beta-lactamase were adherent. All the adherent strains, and even the two strains producing only the SHV-1 enzyme, harbored at least one self-transmissible R plasmid. At variance for CAZ-1/TEM-5 or CAZ-5/SH V-4 beta-lactamase-producing K. pneumoniae strains, curing and mating experiments demonstrated that the self-transmissible R plasmids encodi ng the TEM-1, CTX-1/TEM-3, CAZ-2/TEM-8, CAZ-6/TEM-24, or CAZ-7/TEM-16 beta-lactamase were not involved in the adhesion of K. pneumoniae stra ins to intestinal epithelial cells. Nevertheless, there was an associa tion of multiple antibiotic resistance, including resistance to extend ed-spectrum cephalosporins, and adhesive properties in K. pneumoniae c linical isolates.