A retrospective study was conducted to scrutinize the antibiotic resistance, resistance genes, and clonal relationship of 257 Escherichia coli (E. coli) isolates from bloodstream infections in Ningxia from 2022 to 2023. The study deployed the Polymerase Chain Reaction (PCR) method to detect several resistance genes and determine the clonal relationship via multilocus sequence typing.
The isolates came predominantly from the Emergency, Hepatobiliary Surgery, and Haematology Departments, representing 56.6%, 7.3%, and 6.2% of the total respectively. Antibiotic susceptibility testing of the 257 isolates revealed the highest rates of resistance to ampicillin and cefazolin – found in 82.8% and 71.6% of the cases. Notably, none of the isolates showed resistance to tigecycline.
Upon testing different resistance genes, researchers found the most frequent genes were blaCTX−M, blaSHV, and blaTEM, present in 60.32%, 20.63%, and 30.16% of cases respectively. Moreover, aac(6′)-Ib-cr emerged as the major quinolone resistance gene. The results indicated that the predominant sequence types (STs) were ST69, ST131, and ST1193.
Researchers concluded that in the studied hospital, E. coli demonstrated resistance to most commonly used antibiotics, thereby recommending cefoperazone/sulbactam, cefotetan, amikacin, and tigecycline for empirical treatment of bloodstream infections. Finally, a high level of genetic diversity was noticed among the isolates.
Source: https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-025-10658-3