Relationship between adhesion to intestinal Caco-2 cells and multidrug resistance in Klebsiella pneumoniae clinical isolates.
Klebsiella pneumoniae is an opportunistic gram-negative pathogen involved in outbreaks of nosocomial infections in intensive care units. Strains 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 gastrointestinal tracts of patients have been shown to be the reservoir for nosocomial strains of K. pneumoniae, we looked for a correlation between antibiotic resistance and adhesion of K. pneumoniae strains to intestinal cells. We investigated adhesion to the human intestinal epithelial 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 strains). Just 7.7% (2 strains) of the 26 strains producing only the chromosomally encoded SHV-1 beta-lactamase adhered to the Caco-2 cell line, whereas 68.5% (24 strains) of the 35 strains producing a plasmid-encoded 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/SHV-4 beta-lactamase-producing K. pneumoniae strains, curing and mating experiments demonstrated that the self-transmissible R plasmids encoding 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 strains to intestinal epithelial cells. Nevertheless, there was an association of multiple antibiotic resistance, including resistance to extended-spectrum cephalosporins, and adhesive properties in K. pneumoniae clinical isolates.
Di Martino
P
P
Laboratoire de Bactériologie, Faculté de Pharmacie, Clermont-Ferrand,France.
Sirot
D
D
Joly
B
B
Rich
C
C
Darfeuille-Michaud
A
A
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001422:Bacterial Adhesion; D018938:Caco-2 Cells; D003227:Conjugation, Genetic; D003428:Cross Infection; D018432:Drug Resistance, Multiple; D004926:Escherichia coli; D005602:France; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology*; D011815:R Factors / Q000032:analysis; D001618:beta-Lactamases / Q000378:metabolism
D000900:Anti-Bacterial Agents; C054882:beta-lactamase PIT-2; D001618:beta-Lactamases