In-Vitro Activity of Ceftazidime-Avibactam and Comparator Agents Against Carbapenem-Resistant Gram-Negative Isolates at a Tertiary Care Hospital in Lahore, Pakistan: A Cross-Sectional Study.
4 affiliations
- 1Department of Pathology (Microbiology), National Hospital and Medical Centre, Lahore, Punjab, Pakistan.
- 2Services Institute of Medical Sciences, Lahore, Punjab, Pakistan.
- 3Department of Medicine, Jinnah Sindh Medical University, Karachi, Sindh, Pakistan.
- 4Department of Medicine, Kabul University of Medical Sciences Abu Ali Sina, Kabul, Kābul, Afghanistan.
Abstract
Carbapenem-resistant Gram-negative bacteria are WHO critical priority pathogens with few treatment options. Ceftazidime-avibactam (CAZ-AVI) inhibits serine carbapenemases (KPC, OXA-48-like) but not metallo-β-lactamases, which are common in South Asia. Local data are scarce; we assessed CAZ-AVI and comparator activity in Pakistan. In this laboratory-based cross-sectional study, consecutive non-duplicate carbapenem-resistant isolates from a tertiary care centre in Lahore (December 2024-May 2025) were tested by MIC and disc diffusion with CLSI interpretation. The primary outcome was CAZ-AVI susceptibility with exact binomial 95% confidence intervals; comparisons used Fisher's exact test, McNemar's test, and multivariable logistic regression. Of 210 isolates, 200 had CAZ-AVI results; susceptibility was 70.5% (141/200; 95% CI 63.7-76.7). It varied by sample source (p = 0.008), from 81.2% in blood cultures to 38.5% (5/13) in other specimens, but not by organism, department, age, or gender. In paired comparisons, CAZ-AVI susceptibility exceeded gentamicin, ciprofloxacin, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole, was similar to amikacin, and was lower than colistin, fosfomycin, and tigecycline. Among 59 resistant isolates, colistin (94.5%), fosfomycin (92.9%), tigecycline (79.5%), and chloramphenicol (76.7%) were most active. Sample source was the only independent predictor (other specimens vs blood culture: adjusted OR 0.18, 95% CI 0.05-0.68; imprecise). CAZ-AVI was active in vitro against 70.5% of carbapenem-resistant Gram-negative isolates. Because nearly one-third were resistant, these findings support surveillance and susceptibility-guided rather than empirical use. Metallo-β-lactamase production is a plausible but unconfirmed explanation. Molecular characterization and evaluation of CAZ-AVI plus aztreonam are needed.
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BibTeX
@article{yunus2026invitro,
title = {{In-Vitro Activity of Ceftazidime-Avibactam and Comparator Agents Against Carbapenem-Resistant Gram-Negative Isolates at a Tertiary Care Hospital in Lahore, Pakistan: A Cross-Sectional Study.}},
author = {Faryal Yunus and Obaid Ur Rehman and Muhammad Murtaza and Safa Mazhar and Abedin Samadi and Ahmed Asad Raza},
journal = {MicrobiologyOpen},
year = {2026},
month = nov,
doi = {10.1002/mbo3.70449},
url = {https://europepmc.org/article/MED/42975008},
note = {CC BY},
}
RIS
TY - JOUR
TI - In-Vitro Activity of Ceftazidime-Avibactam and Comparator Agents Against Carbapenem-Resistant Gram-Negative Isolates at a Tertiary Care Hospital in Lahore, Pakistan: A Cross-Sectional Study.
AU - Faryal Yunus
AU - Obaid Ur Rehman
AU - Muhammad Murtaza
AU - Safa Mazhar
AU - Abedin Samadi
AU - Ahmed Asad Raza
PY - 2026
DA - 2026/11/03
JO - MicrobiologyOpen
DO - 10.1002/mbo3.70449
UR - https://europepmc.org/article/MED/42975008
AB - Carbapenem-resistant Gram-negative bacteria are WHO critical priority pathogens with few treatment options. Ceftazidime-avibactam (CAZ-AVI) inhibits serine carbapenemases (KPC, OXA-48-like) but not metallo-β-lactamases, which are common in South Asia. Local data are scarce; we assessed CAZ-AVI and comparator activity in Pakistan. In this laboratory-based cross-sectional study, consecutive non-duplicate carbapenem-resistant isolates from a tertiary care centre in Lahore (December 2024-May 2025) were tested by MIC and disc diffusion with CLSI interpretation. The primary outcome was CAZ-AVI susceptibility with exact binomial 95% confidence intervals; comparisons used Fisher's exact test, McNemar's test, and multivariable logistic regression. Of 210 isolates, 200 had CAZ-AVI results; susceptibility was 70.5% (141/200; 95% CI 63.7-76.7). It varied by sample source (p = 0.008), from 81.2% in blood cultures to 38.5% (5/13) in other specimens, but not by organism, department, age, or gender. In paired comparisons, CAZ-AVI susceptibility exceeded gentamicin, ciprofloxacin, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole, was similar to amikacin, and was lower than colistin, fosfomycin, and tigecycline. Among 59 resistant isolates, colistin (94.5%), fosfomycin (92.9%), tigecycline (79.5%), and chloramphenicol (76.7%) were most active. Sample source was the only independent predictor (other specimens vs blood culture: adjusted OR 0.18, 95% CI 0.05-0.68; imprecise). CAZ-AVI was active in vitro against 70.5% of carbapenem-resistant Gram-negative isolates. Because nearly one-third were resistant, these findings support surveillance and susceptibility-guided rather than empirical use. Metallo-β-lactamase production is a plausible but unconfirmed explanation. Molecular characterization and evaluation of CAZ-AVI plus aztreonam are needed.
SN - 2045-8827
ER -