Antibiotic Resistance in Pregnancy-Related UTIs: New Data Reveal E. coli Patterns and Clinical Risks

How well do your empiric antibiotic choices match local resistance trends in pregnant women with UTIs? With up to 40% of pregnant inpatients showing positive urine cultures and growing antibiotic resistance, the stakes for targeted therapy have never been higher.

Study Design: Comparing Pregnant and Nonpregnant UTI Patients

This retrospective cohort study analyzed 380 women (aged 18–45) admitted for UTIs at a single center in China from 2016 to 2023. Researchers divided them into pregnant (n=187) and nonpregnant (n=193) groups to compare:

Pathogen profiles

Antibiotic sensitivity and resistance

Associated complications

Urine cultures and susceptibility testing followed standardized protocols, and patient demographics, comorbidities, and hospitalization data were collected.

Key Findings: E. coli Still Leads—But Resistance is Rising

Gram-negative bacteria—especially Escherichia coli—remained the primary cause of UTIs in both groups. In pregnant women:

E. coli accounted for 36.8% of isolates (vs. 58.9% in nonpregnant women).

Extended-spectrum β-lactamase (ESBL)-producing E. coli was detected in 32.1% of E. coli-positive cases.

High resistance rates were observed for ceftriaxone (50%), levofloxacin (32.1%), and aztreonam (35.7%).

No resistance was seen to piperacillin-tazobactam or meropenem.

Pregnant women experienced higher rates of complications like hydronephrosis, anemia, and hypoalbuminemia. Surprisingly, Mycoplasma infections were also more common in pregnant patients (53.5%) compared to nonpregnant (35.8%).

Clinical Implications: Tailoring Therapy in Pregnant Women

The high rate of ESBL+ E. coli and resistance to commonly used antibiotics underscores the need for culture-driven therapy in pregnant patients. While third-generation cephalosporins such as ceftriaxone are commonly recommended, local resistance patterns may limit their effectiveness.

Carbapenems (like meropenem) and beta-lactam/beta-lactamase inhibitor combinations (such as piperacillin-tazobactam) remain highly effective.

Nitrofurantoin—often recommended elsewhere—is less favored in China during the later stages of pregnancy due to fetal risks.

Mycoplasma, despite its high detection rate, may not require antibiotic treatment, as symptoms often resolve without intervention.

So What? A Call for Surveillance and Rational Antibiotic Use

For clinicians, these findings highlight the importance of:

Surveillance of local resistance trends

Choosing antibiotics based on up-to-date susceptibility data

Addressing complicating factors—such as anemia or hydronephrosis—to reduce UTI risk and improve outcomes in pregnancy

Conclusion

The landscape of urinary tract infections in pregnancy is evolving, with rising antibiotic resistance and complex pathogen profiles. Empiric therapy must be continually re-evaluated, and culture-based management is critical to optimize outcomes for both mother and fetus.

Key points

Gram-negative bacteria, mainly E. coli, are the leading cause of UTIs in pregnant women.

ESBL-producing strains and resistance to common antibiotics are increasingly prevalent.

Piperacillin-tazobactam and meropenem remain highly effective against resistant E. coli.

Pregnant women with UTIs are more likely to have complications like anemia and hydronephrosis.

Mycoplasma is common in pregnant UTI patients, but often resolves without specific antibiotic therapy.

Citation:

Jian Feng, Yingying Zhou, Ya Jun Weng, Yuqing Ding, Lichen Xu, Wenkai Xia, Junnan Wu, Xiangcheng Xie. Pathogenic profile and drug susceptibility to urinary tract infection during pregnancy: a retrospective hospital-based comparative cohort study. BMC Pregnancy and Childbirth. 2026; [In Press]. doi:10.1186/s12884-026-09982-6