Drug resistance characteristics and molecular typing of Escherichia coli isolates from neonates in class A tertiary hospitals: A multicentre study across China.

Objectives: Escherichia coli is a common pathogen causing invasive bacterial infections in neonates. In recent years, clinical antimicrobial susceptibility testing has demonstrated an increased rate of drug-resistant E. coli infections. This study aimed to analyse the resistance characteristics of E. coli against common antimicrobial agents, and perform multilocus sequence typing (MLST) in clinical strains of E. coli collected from Chinese neonates.

Methods: Culture-positive specimens of E. coli were collected from neonates in seven class A tertiary hospitals located in seven cities across different provinces in China between November 2019 and October 2020. E. coli isolated from these specimens were subjected to antimicrobial susceptibility testing (by broth microdilution method), extended-spectrum β-lactamase (ESBL) detection, and MLST.

Results: A total of 223 E. coli strains were isolated, with an overall resistance rate of 87.4%, an ESBL-positive rate of 48.0%, and a multidrug resistance rate of 42.2%. Among the 20 antimicrobial agents tested, E. coli strains showed the highest resistance rates against cefotaxime (59.2%), trimethoprim/sulfamethoxazole (56.5%), doxycycline (39.9%), ciprofloxacin (36.8%), and aztreonam (31.0%). The resistance rates of E. coli strains isolated from children's hospitals against piperacillin/tazobactam, cefotaxime, ciprofloxacin, trimethoprim/sulfamethoxazole, and carbapenems, were significantly higher than those of strains isolated from maternity and child health hospitals. The primary E. coli multilocus sequence types were ST1193, ST95, ST73, ST410, and ST131. The ESBL production rates and multidrug resistance rates of ST1193, ST410, and ST131 were significantly higher than those of ST95 and ST73. Significantly, more strains of E. coli ST1193 and ST410 were isolated from children's hospitals than from maternity and child health hospitals.

Conclusions: The rates of antimicrobial agent resistance in E. coli isolates from hospitalised neonates in China were high. The increased number of strains of E. coli ST1193 and ST410 was the reason for higher resistance rates to multiple antimicrobial agents in E. coli from children's hospitals compared with those from maternal and child health hospitals.