Possible Association of Carbapenemase Production with Susceptibility Pattern and Resistance Genes Among Carbapenemase Producing Enterobacterales from Blood Isolates or Bacteremic Patients

Abstract

Background: Bacteremia caused by Enterobacteriaceae strains is associated with increased mortality rates due to antibiotic resistance, including carbapenems. The current study investigated antimicrobial susceptibility, carbapenemase production, and the presence of resistance genes in Enterobacteriaceae isolated from blood cultures.

Methods: Eighty pure Enterobacteriaceae isolates were collected from positive blood cultures from four Jordanian hospitals. Antimicrobial susceptibility was investigated using the Kirby-Bauer method. Chromogenic culture media was used for the Hodge test, and the carbapenemase production was determined using the Carba NP test. The PCR technique was used to identify genes that confer resistance.

Results: Most isolates were positive for Klebsiella pneumoniae (55%), followed by Escherichia coli (37.5%) and Enterobacter cloacae (5%). The highest rates of resistance were observed against ampicillin (90%), cefazolin (76.7%), cefotaxime (70%), and ceftriaxone (65%). The lowest rate of resistance was observed against imipenem (13.7%). The frequencies of carbapenemase production, as determined by chromogenic culture media, the modified Hodge test, and the Carba NP Test, were 18.75%, 21.25%, and 10%, respectively. The identified carbapenemase resistance genes were bla-KPC (10%), bla-NDM (15%), bla-VIM (5%), and bla-OXA-48 (6.25%). A significant association (P < 0.05) was found between multidrug resistance and carbapenemase production.

Conclusion: A low percentage of carbapenem-resistant Enterobacteriaceae was observed among Jordanian patients with bacteremia. A significant association was observed between carbapenemase production and multi-drug resistance. The results can be used in the management of bacteremic patients in Jordan.

Keywords: Enterobacteriaceae; Jordan; antibiotic resistance; bacteremia; carbapenemase; gene.

Figure 1

Image of representative gel for (A) KPC gene detection. L: Ladder, PC: Positive Control, NC: Negative Control. Lanes 24, 27, 31 and 32: samples demonstrating KPC genes (498 bp), (B) VIM genes detection. L: Ladder, PC: Positive Control, NC: Negative Control. Lanes 17, 19 and 27: samples demonstrating VIM genes (390 bp), (C) OXA-48 gene detection. L: Ladder, PC: Positive Control, NC: Negative Control. Lanes 21, 35 74 and 80: samples demonstrating OXA-48 genes (238 bp), and (D) NDM gene detection. L: Ladder, PC: Positive Control, NC: Negative Control. Lanes 30, 35, 39 and 49: samples demonstrating NDM genes (521 bp).