E. coli resistance in Iran: high ESBL rates and rising resistance to last-line agents

Design

Systematic review and random-effects meta-analysis of prevalence studies (One Health framework)

Population

368 studies of E. coli from humans, animals, food and the environment in Iran, 2010 to January 2025

Primary outcome

Pooled prevalence of antimicrobial resistance and resistance genes

Effect

Penicillins 71.7% (95% CI 65.6 to 76.6); fosfomycin 6.8% (5.2 to 8.5); ESBL 47.2%, AmpC 20.2%, MBL 14.1%

This systematic review pooled 368 studies of E. coli from humans, animals, food and the environment in Iran, published between 2010 and January 2025. Risk of bias was assessed with the JBI prevalence checklist, and random-effects models gave pooled prevalence for each antibiotic.

Resistance was highest to penicillins (71.7%, 95% CI 65.6 to 76.6) and lowest to fosfomycin (6.8%, 5.2 to 8.5). Resistance to ceftizoxime, ertapenem, streptomycin, piperacillin-tazobactam and colistin increased over time. Phenotypically, 47.2% of isolates were ESBL producers, 20.2% AmpC and 14.1% metallo-beta-lactamase producers. Among ESBL producers, the genes blaCTX-M, blaTEM and blaSHV were found in 68.2%, 58.5% and 24.4%.

These are Iranian data drawn from many heterogeneous studies, and the abstract does not report heterogeneity. They do not describe Indian resistance, and local antibiograms should drive empirical choices. The reason to read them is the pattern: high ESBL prevalence, with oral options such as fosfomycin retaining activity, and a rising trend for agents held in reserve.

• Use your own hospital and community antibiogram to choose empirical therapy, not data from another country.
• Send urine and blood cultures before antibiotics in patients with complicated infection.
• Consider ESBL risk (recent antibiotics, hospitalisation, travel) when choosing for a septic patient.
• Review empirical therapy at 48 to 72 hours against culture and susceptibility results.
• Support stewardship rules for carbapenems and colistin; rising resistance to them is the concern.

Why it matters

It is a reminder that empirical choices rest on local resistance data, and that agents held in reserve are already losing ground in some regions.

Don't overread it

These are Iranian data pooled from many studies of varying quality; they do not describe resistance in India or in any other single setting.

The statistics, in plain English

A pooled prevalence of 47.2% means almost half of tested isolates were ESBL producers across the included studies, but pooled figures from very different hospitals and years hide wide variation between settings. The 95% intervals shown are for the pooled estimate, not for any single hospital.

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