Purpose: Bloodstream infections (BSIs) cause morbidity and mortality in postpartum patients, resulting in poor prognosis for both mother and neonate. Gram-negative bacteremia is a public health threat, with high mortality among vulnerable populations and significant global economic costs. Gram-negative bacteremia and antimicrobial resistance are increasing. This study retrospectively analyzed the pathogen distribution and drug sensitivity among postpartum patients with BSIs to identify appropriate antibacterial agents for perioperative therapy.
Material and Methods: All bacteremia cases between January 2015 and December 2020 from three Health Centers for Women and Children in Chongqing, China, were retrospectively reviewed. Clinical data were collected from medical records and charts. Blood samples were cultured by BD BACTEC FX200. Bacterial and fungal species and bacterial susceptibility were identified by a BD Phoenix^TM M50 automatic detection machine.
Results: In total, 274 pathogenic strains were isolated from 272 blood samples. Excluding 25 suspected contamination strains, 248 blood samples yielded 249 microorganisms, including 214 gram-negative bacteria (85.9%), 34 gram-positive bacteria (13.6%), and 1 fungus (0.5%). Escherichia coli  (E. coli ) was the most frequently isolated pathogen, both overall and among gram-negative bacilli (73.5%). Streptococcus agalactiae  represented 3.6% of gram-positive cocci (n = 9). Laboratory-confirmed anaerobic infections comprised 9.2% of cases (n = 23). Additionally, 47.4% of postpartum patients with BSIs suffered premature rupture of membranes (PROM), a suspected infection risk factor. Drug sensitivity levels remained unchanged for less commonly used drugs, but resistance increased against commonly used drugs. Specifically, E. coli  resistance against fourth-generation cephalosporins increased during this study period.
Conclusion: E. coli  is the most common gram-negative bacillus in postpartum patients with BSIs, and increased anaerobic bacterial detections suggest genital tract inflammation control before delivery is necessary. Effective drug resistance monitoring remains necessary to alleviate bacterial resistance, such as preventing inappropriate antibiotic applications.
Keywords: bacteremia, Escherichia coli , anaerobic bacterial, perioperative therapy