An Analysis of the Type and Antimicrobial Resistance of Carbapenemase-Producing Enterobacteriaceae Isolated at the Military Institute of Medicine in Warsaw, Poland, 2009-2016

Background: The number of carbapenemase-producing Enterobacteriaceae cases is increasing, and the infections produced by such pathogens are a worldwide problem. Objectives: The current study aimed at investigating the antibiotic resistance of carbapenemase-producing Enterobacteriaceae pathogens isolated from the biological materials obtained from patients hospitalized in our center, and analyzing the infections caused by such species. Methods: The data were collected from January 2009 to December 2016 from urine, blood, wound exudate, the bronchial tree, abscess, and the abdominal cavity samples as well as cloacal swabs for fecal carriage. The samples were processed according to generally accepted microbiological procedures. Results: The current study analyzed 122 Enterobacteriaceae isolates that can produce the carbapenemases: Klebsiella pneumoniae carbapenemase (KPC, 60%), New Delhi metallo-β-lactamase (NDM, 39.6%), and carbapenem-hydrolyzing oxacillinase (OXA-48, 0.8%). Of these 122 samples, 117 (96%) were K. pneumoniae, two (1.6%) K. oxytoca, two (1.6%) Escherichia coli, and one (0.8%) was Citrobacter freundii. In 2015 and 2016, a high isolation percentage of K. pneumoniae NDM pathogens was observed. All analyzed carbapenemaseproducing Enterobacteriaceae were susceptible to colistin; 93% of the isolates were susceptible to tigecycline, and about 50% of the KPC pathogens were susceptible to aminoglycosides. The carrier state of carbapenemase-producing Enterobacteriaceae was confirmed in 35% of cases. Conclusions: The current study results were comparable to the ones concerning the general microbiological situation in Europe. The relatively high incidence of NDM pathogens is alarming and may be resulted from the epidemiological situation in our region.