Frequency and Resistance Pattern of Carbapenemases (Class A & B) in E. Coli and Klebsiella Species

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Hina Faisal
Amber Yasmeen Alvi
Azra Idris
Maliha Yasmeen
Naseha Mushtaq
Hira Zafar Siddiqui


Abstract: Background: Carbapenems are potent and strong antibiotics that are usually reserved as last resort for bacteria possessing basic antibiotic resistance. These are broad spectrum drugs with more effective coverage against gram negative organisms. The antibiotic resistance pattern observed in bacteria possessing chromosomal group 2f ?-lactamases is unique. It involves resistance to carbapenems while remaining sensitive to broadly attacking cephalosporins.

Objective: This study aims to provide assessment of frequency of class A & B carbapenamase in E.coli and Klebsiella species producers and establish the resistance pattern from clinical isolates, at a tertiary care hospital in Karachi.

Materials and Methods: This is a cross sectional, prospective study conducted at general hospital liyari, Karachi during Jan 2022- Jan 2023. Sample size was calculated as 400. Samples were divided into Urine samples of urinary tract infection patients (n=150), Pus sample from different sites (n=100), Respiratory tract, tracheal aspirates and sputum sample (n=100) and blood sample from suspected septicemia (n=50). SPSS-22 was used to enter and analyze the data. Chi-square test was used to analyze significance between two mean values, keeping ?0.05 as significant p-value.

Result: Distribution of microorganisms were reported as 120 (41.1%), 80 (28.5%), 2 (0.69%), 24 (8.36%), 55 (19.1%) and 6 (2%) of E. coli, Klebsiella Pneumonia, K.Oxytoca, Gram positive. Gram negative and Yeast respectively. The confirmed presence of carbapenemase (CP) was identifies in urine sample as 4/6 (26.6%) E.coli and 2/6 (13.3%) Klebsiella, while pus samples identifies 3/4 (20%) E.coli and 1/4 (6.6%) Klebsiella. Similarly samples of respiratory tract identifies 2/5 (13%) of E.coli and 3/5 (20%) of Klebsiella. The calculated p-value was insignificant with 0.834 and 0.913 for E.coli and Klebsiella respectively.

Conclusion: This study concludes that E.coli is by far the most frequently reported microorganism from class B while class A organisms are in lower frequencies. CRE indicated higher resistance from non-?-lactam antibiotics, limiting treatment options.

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Faisal H, Alvi AY, Idris A, Yasmeen M, Mushtaq N, Siddiqui HZ. Frequency and Resistance Pattern of Carbapenemases (Class A & B) in E. Coli and Klebsiella Species. Nat J Health Sci [Internet]. 2024Jun.28 [cited 2024Jul.19];9(2):115-20. Available from:
Research Article

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