Prevalence of carbapenem-resistant Klebsiella pneumoniae and associated carbapenemase genes among clinical isolates in Iran: a systematic review and meta-analysis

Background Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged as a major global public health threat due to limited treatment options and high morbidity and mortality. This systematic review and meta-analysis aimed to estimate the pooled prevalence of CRKP among clinical isolates in Iran based on studies incorporating molecular detection of carbapenemase-encoding genes and to characterize the distribution of major carbapenemase-encoding genes among clinical isolates. Methods Relevant studies conducted in Iran and involving clinical K. pneumoniae isolates obtained from human patients were identified through searches of PubMed/MEDLINE, Scopus, ScienceDirect, Springer, Wiley Online Library, Google Scholar, and the Iranian Scientific Information Database (SID) from January 2015 to December 2025. Eligible studies were required to provide sufficient data on the prevalence of CRKP and/or carbapenemase-encoding genes. Studies without relevant prevalence data or based exclusively on non-clinical samples were excluded. Statistical analyses were performed using R software (version 4.5.2). Pooled prevalence estimates were calculated using a random-effects model. Heterogeneity was assessed using Cochran’s Q test and the I² statistic. Potential small-study effects were assessed using Egger’s regression test, and statistical significance was defined as a two-sided P value < 0.05. Results Forty-six studies (n = 6,708 isolates) were included. Pooled CRKP prevalence was 51% (95% CI: 38%-63.9%). Significant heterogeneity was found among the included studies (I² = 96.1%, P < 0.001). Among carbapenemase genes, the blaOXA-48-like family had the highest pooled prevalence (66%, 95% CI: 25%-92%), followed by blaOXA-48 (45%, 29–63%) and blaNDM (29%, 18–43%). The pooled prevalence of blaKPC, blaVIM, and blaIMP were 26%, 18%, and 12%, respectively. Conclusion Our findings suggest that CRKP represents a major public health concern in Iran, with blaOXA-48-like and blaNDM among the most frequently detected carbapenemase-encoding genes. These findings highlight an urgent need for continuous molecular surveillance, strengthened antimicrobial stewardship, and effective infection prevention and control measures to limit the spread of CRKP.