Imipenem-resistant Pseudomonas aeruginosa gastrointestinal carriage among hospitalized patients: risk factors and resistance mechanisms.
Risk factors for imipenem (IMP)-resistant Pseudomonas aeruginosa (IRPA) digestive carriage were analyzed, and genetic events contributing to select resistant isolates in patients exposed to IMP were investigated. Among the 150 patients with hospital-acquired P. aeruginosa digestive carriage, 38 isolates were IRPA. DNA pulsotypes revealed 16 distinct clones. In 4 patients, a second P. aeruginosa isolate showed resistance to IMP compared with the initial susceptible isolate. By comparing the different oprD sequences between IMP-susceptible P. aeruginosa and IRPA strains, a genetic event was systematically found for each resistant isolate, leading to either the absence of OprD or a truncated porin. The multivariate analysis demonstrated that prior IMP exposure was associated with IRPA carriage. In summary, we confirmed that IMP use selects for IRPA in the gut flora. Cross-transmission, however, was frequently observed in intensive care units. Combining epidemiologic approach and molecular analysis is a powerful tool to delineate mechanisms of emerging resistance.
Department of Bacteriology-Hygiene, Nantes University Hospital, France. didier.lepelletier@chu-nantes.fr
Didier
D
Lepelletier
Anne
A
Cady
Nathalie
N
Caroff
Julie
J
Marraillac
Alain
A
Reynaud
Jean-Christophe
JC
Lucet
Stéphane
S
Corvec
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D002353:Carrier State / Q000382:microbiology*; D015331:Cohort Studies; D003428:Cross Infection / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D016015:Logistic Models; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D018272:Porins / Q000235:genetics; D011446:Prospective Studies; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D012007:Rectum / Q000382:microbiology*; D012307:Risk Factors
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D018272:Porins; D015378:Imipenem