Phenotypic and genotypic detection of resistance mechanisms in carbapenem-resistant gram-negative bacteria isolated from Egyptian ICU patients with first emergence of NDM-1 producing Klebsiella oxytoca

• Published in: Iranian journal of microbiology Vol. 14; no. 6; pp. 832 - 840
• Main Authors: Fawzy, Reem Hossam, Gad, Gamal Fadl Mahmoud, Mohamed, Heba Ahmed
• Format: Journal Article
• Language: English
• Published: Iran Tehran University of Medical Sciences 01-12-2022
• Subjects: Antimicrobial drug resistance; Carbapenems; Gram-negative bacteria; Intensive care units; Klebsiella oxytoca; Original; Intensive care units; Antimicrobial drug resistance; Klebsiella oxytoca; Gram-negative bacteria; Carbapenems
• ISSN: 2008-3289; 2008-4447
• DOI: 10.18502/ijm.v14i6.11258

Carbapenems are considered the last resort to treat several infections, particularly in intensive care units (ICUs). However, increasing carbapenem resistance is problematic because it leads to high morbidity and mortality rates. This study aimed to determine the rate of carbapenem resistance among Gram-negative bacteria collected from patients in ICUs and to identify their resistance mechanisms using phenotypic and genotypic methods.
Antimicrobial susceptibility testing was carried out using the disc diffusion method among 180 Gram-negative bacterial isolates. Productions of carbapenemases, metallo-beta-lactamases (MBLs) and the harboring of carbapenemase-encoding genes, were detected in 40 selected carbapenem-resistant Gram-negative bacteria (CR-GNB).
Of 40 selected CR-GNB isolates, 28 (70%), and 20 (50%) isolates were phenotypically positive for carbapenemase, and MBL production, respectively. Furthermore, 22 (55%) showed amplification of one or more of the carbapenemase-encoding genes, including
,
, and
. This study described the first emergence of NDM-1 producing
in Egyptian ICUs.
High incidence of CR-GNB detected in the ICUs in our study area may be attributed to the overuse of antibiotics, including carbapenems, and improper application of infection control measures. These findings confirm the need for the application of a strict antibiotic stewardship program.