title: Risk factors and clinical significance of ertapenem-resistant Klebsiella pneumoniae in hospitalised patients.
abstract: Ertapenem-resistant Klebsiella pneumoniae (ER-Kp) is an emerging healthcare-associated pathogen. In order to identify risk factors associated with ER-Kp acquisition, the records of 100 patients from whom K. pneumoniae had been isolated between July 2008 and December 2009 were reviewed. These comprised 38 with ER-Kp (28 infected, 10 colonised) and 62 with ertapenem-susceptible K. pneumoniae (ES-Kp) (43 infected, 19 colonised). Multilocus sequence typing (MSLT) and porin gene investigation performed on 25 ER-Kp strains showed that 24 belonged to the ST37 lineage, expressing a novel OmpK36 variant and not expressing OmpK35. Breakthrough bacteraemia occurred in 13 (52%) of 25 bloodstream infections (BSIs). Among nine ER-Kp BSIs, five were complicated by breakthrough bacteraemia, of which four developed during carbapenem therapy. Among 16 ES-Kp BSIs, breakthrough bacteraemia developed in eight patients (50%), but only one occurred (12%) during carbapenem therapy. Logistic regression analysis showed that carbapenems (odds ratio: 12.9; 95% confidence interval: 3.09-53.7; P < 0.001), second generation cephalosporins (11.8; 1.87-74.4; P < 0.01), endoscopy (5.59; 1.32-23.6; P < 0.02), acute renal failure (5.32; 1.13-25.1; P=0.034) and third generation cephalosporins (4.15; 1.09-15.8; P < 0.01) were independent risk factors for acquisition of ER-Kp. Our findings confirm that prior use of certain antimicrobials, specifically carbapenems and cephalosporins, are primary independent risk factors for colonisation or infection with ER-Kp.
authors: Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy. giovanni.orsi@uniroma1.it
authors: G B
authors: GB
authors: Orsi
authors: A
authors: A
authors: García-Fernández
authors: A
authors: A
authors: Giordano
authors: C
authors: C
authors: Venditti
authors: A
authors: A
authors: Bencardino
authors: R
authors: R
authors: Gianfreda
authors: M
authors: M
authors: Falcone
authors: A
authors: A
authors: Carattoli
authors: M
authors: M
authors: Venditti
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D000077727:Ertapenem; D005260:Female; D005838:Genotype; D006760:Hospitalization; D006801:Humans; D007710:Klebsiella Infections / Q000150:complications / Q000188:drug therapy* / Q000453:epidemiology* / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D008297:Male; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D018272:Porins / Q000235:genetics; D012307:Risk Factors; D016896:Treatment Outcome; D018440:beta-Lactam Resistance; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D018272:Porins; D047090:beta-Lactams; D000077727:Ertapenem