Increasing Frequency of New Delhi Metallo-beta-Lactamase and Klebsiella pneumoniae Carbapenemase Resistant Genes in a Set of Population of Karachi.

Objective: To determine the frequency of Klebsiella pneumoniae Carbapenemase (blaKPC) and New Delhi Metallo-Beta-Lactamase (blaNDM) resistant genes among clinical isolates of Enterobacterales in a set of Karachi population.

Study Design: An observational study.

Place And Duration Of Study: Department of Microbiology, Dr. Ziauddin University Hospital, Karachi, Pakistan, from January 2019 to December 2020.

Methodology: A total of 2100 clinical isolates of Enterobacterales were collected. All isolates of Carbapenem-Resistant Enterobacterales (CRE) (Escherichia coli, Enterobacter and Klebsiella species) on the basis of Meropenem screening test positivity were included in the study. DNA was extracted and PCR was performed for resistant genes detection. Frequencies and percentages were computed for categorical variables and mean values and standard deviation for quantitative variables.

Results: Among 2100 isolates of Enterobacterales, the majority were E. coli 1260 (60%), followed by Klebsiella species 462 (22%), and Enterobacter species 210 (10%). The sources of CRE isolates included 34 (25%) from respiratory (tracheal aspirate, pleural fluid, and gastric lavage); 33 (24.26%) urine, 32 (25.53%) pus, 15 (11.03%) blood, and 20 (14.7%) others (ascitic fluid, stents, and tissue). All isolates of CRE were sensitive (100%) to Colistin, Tigecycline and Fosfomycin. Biochemically confirmed CRE 136 (6.5%) isolates, (79 (58%) males and 57 (42%) females), were selected for detecting resistant genes. The PCR showed 32 (23.52%) positive for both NDM and KPC resistant genes, 28 (20.58%) for NDM and 19 (13.97%) for KPC alone. Out of 79 followed up patients, 58 (73.4%) expired while 21 (26.6%) were discharged.

Conclusion: The frequency of blaNDM and blaKPC resistant genes in CRE isolates depicted increasing trend. Colistin, Fosfomycin, and Tigecycline showed high antimicrobial sensitivities in vitro. Further measures need to be applied for CRE with comprehensive resistant genes detection to curtail antimicrobial resistance.

Key Words:  Frequency, KPC, NDM, Klebsiella species, Carbapenemases, Enterobacterales E.coli.