Ertapenem-resistant Klebsiella pneumoniae (ER-Kp) is an emerging healthcare-associated pathogen. In order to identify risk factors associated to ER-Kp acquisition the records of 100 patients with K. pneumoniae isolation from July 2008 to December 2009 were reviewed. Thirty-eight patients with ER-Kp (28 infected, 10 colonized) and 62 patients with ertapenem-susceptible K. pneumoniae (ES-Kp) (43 infected, 19 colonized) were included. Multilocus sequence typing (MSLT) and porin gene investigation in 25 ER-Kp strains showed that 24 belonged to the ST37 lineage, expressing the novel OmpK36 variant and not producing the OmpK35 due to a non-sense mutation. Breakthrough bacteraemias occurred in 13 (52%) out of 25 bloodstream infections (BSIs), five (55%) out of nine were in ER-Kp group and four (80%) of these developed during carbapenem therapy. In the 16 ES-Kp BSIs breakthrough bacteraemias developed in eight patients (50%), but only one (12%) during carbapenem therapy. Logistic regression analysis showed that carbapenems (OR= 12,9; 95%CI 3,09 – 53,7; p<0.001), 2nd generation cephalosporins (OR= 11.8; 95%CI 1.87 – 74.4; p<0.01), endoscopy (OR= 5.59; 95%CI 1.32 – 23.6; p<0.02), acute renal failure (OR= 5.32; 95%CI 1.13 – 25.1; p=0.034) and 3rd generation cephalosporins (OR= 4.15; 95%CI 1.09 – 15.8; p<0.01) were independent risk factors for ER-Kp acquisition. Although not significant, among the 71 infected patients mortality was higher in ER-Kp (39.3%) than ES-Kp (27.9%). Our findings confirm that prior use of certain antimicrobials, specifically carbapenems and cephalosporins are primary independent risk factors for the development of ertapenem resistance.
Risk factors and clinical significance of endemic ertapenem resistant Klebsiella pneumoniae isolates in hospitalized patients
M. Falcone;
2011-01-01
Abstract
Ertapenem-resistant Klebsiella pneumoniae (ER-Kp) is an emerging healthcare-associated pathogen. In order to identify risk factors associated to ER-Kp acquisition the records of 100 patients with K. pneumoniae isolation from July 2008 to December 2009 were reviewed. Thirty-eight patients with ER-Kp (28 infected, 10 colonized) and 62 patients with ertapenem-susceptible K. pneumoniae (ES-Kp) (43 infected, 19 colonized) were included. Multilocus sequence typing (MSLT) and porin gene investigation in 25 ER-Kp strains showed that 24 belonged to the ST37 lineage, expressing the novel OmpK36 variant and not producing the OmpK35 due to a non-sense mutation. Breakthrough bacteraemias occurred in 13 (52%) out of 25 bloodstream infections (BSIs), five (55%) out of nine were in ER-Kp group and four (80%) of these developed during carbapenem therapy. In the 16 ES-Kp BSIs breakthrough bacteraemias developed in eight patients (50%), but only one (12%) during carbapenem therapy. Logistic regression analysis showed that carbapenems (OR= 12,9; 95%CI 3,09 – 53,7; p<0.001), 2nd generation cephalosporins (OR= 11.8; 95%CI 1.87 – 74.4; p<0.01), endoscopy (OR= 5.59; 95%CI 1.32 – 23.6; p<0.02), acute renal failure (OR= 5.32; 95%CI 1.13 – 25.1; p=0.034) and 3rd generation cephalosporins (OR= 4.15; 95%CI 1.09 – 15.8; p<0.01) were independent risk factors for ER-Kp acquisition. Although not significant, among the 71 infected patients mortality was higher in ER-Kp (39.3%) than ES-Kp (27.9%). Our findings confirm that prior use of certain antimicrobials, specifically carbapenems and cephalosporins are primary independent risk factors for the development of ertapenem resistance.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
