Clinical Outcomes, Risk Factors Associated with Carbapenem-Resistant Klebsiella Pneumoniae Infection


Healthcare-associated infections caused by Klebsiella pneumoniae isolates are increasing and few effective antibiotics are currently available to treat patients. Correa, et al. (2013) observed decreased carbapenem susceptibility among K. pneumoniae isolated from patients at a tertiary private hospital that showed a phenotype compatible with carbapenemase production although this group of enzymes was not detected in any sample. The researchers endeavored to describe the epidemiology and clinical outcomes associated with carbapenem-resistant K. pneumoniae and to determine the antimicrobial resistance mechanisms.
Risk factors associated with carbapenem-resistant K. pneumoniae infections were investigated by a matched case--control study from January 2006 through August 2008. A cohort study was also performed to evaluate the association between carbapenem resistance and in-hospital mortality. Bacterial identification and antimicrobial susceptibility were determined by Vitek 2 and Etest. Carbapenemase activity was detected using spectrophotometric assays. Production of beta-lactamases and alterations in genes encoding K. pneumoniae outer membrane proteins, OmpK35 and OmpK36, were analyzed by PCR and DNA sequencing, as well as SDS-Page. Genetic relatedness of carbapenem resistant isolates was evaluated by pulsed field gel electrophoresis.
Sixty patients were included (20 cases and 40 controls) in the study. Mortality was higher for patients with carbapenem-resistant K. pneumoniae infections compared with those with carbapenem-susceptible K. pneumoniae (50.0 percent versus 25.7 percent). The length of central venous catheter use was independently associated with carbapenem resistance in the multivariable analysis. All strains, except one, carried blaCTX-M-2, an extended-spectrum betalactamase gene. In addition, a single isolate also possessed blaGES-1. Genes encoding plasmid-mediated AmpC beta-lactamases or carbapenemases (KPC, metallo-betalactamases or OXA-carbapenemases) were not detected.
The researchers conclude that K. pneumoniae multidrug-resistant organisms were associated with significant mortality. The mechanisms associated with decreased K. pneumoniae carbapenem susceptibility were likely due to the presence of cephalosporinases coupled with porin alterations, which resulted from the presence of the insertion sequences in the outer membrane encoding genes. Their research was published in BMC Infectious Diseases.

Reference: Correa L, Martino MD, et al. A hospital-based matched case--control study to identify clinical outcome and risk factors associated with carbapenem-resistant Klebsiella pneumoniae infection. BMC Infectious Diseases 2013, 13:80

Related Videos
Set of white bottles with cleaning liquids on the white background. (Adobe Stock 6338071172112 by zolnierek)
Medical investigators going over data. (AdobeStock 589197902 by Wasan)
CDC logo is seen on a laptop. (Adobe Stock 428450603 by monticellllo)
Association for the Health Care Environment (Logo used with permission)
COVID-19 germs, fungi, bacteria objects. (Adobe Stock 584704860 by chawalit)
Ambassador Deborah Birx, , speaks with Infection Control Today about masks in schools and the newest variant.
mRNA technology  (Adobe Stock 485886181 by kaptn)
Ambassador Deborah Birx, MD
Woman lying in hospital bed (Adobe Stock, unknown)
Related Content