Search

Background: OXA-232-producing Klebsiella pneumoniae was first identified in China in 2016, and its clonal transmission was reported in 2019. However, there are no prevalence and genotypic surveillance data available for OXA-232 in China. Therefore, we investigated the trends and characteristics of OXA-232 type carbapenemase in Zhejiang Province, China from 2018 to 2021. Methods: A total of 3278 samples from 1666 patients in the intensive care units were collected from hospitals in Zhejiang Province from 2018 to 2021. Carbapenem-resistant isolates were initially selected by China Blue agar plates supplemented with 0.3 μg/ml meropenem, and further analyzed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry identification, immune colloidal gold technique, conjugation experiment, antimicrobial susceptibility testing and whole genome sequencing. Results: A total of 79 OXA-producing strains were recovered, with the prevalence increased from 1.8% [95% confidence interval (CI): 0.7–3.7%] in 2018 to 6.0% (95% CI: 4.4–7.9%) in 2021. Seventy-eight strains produced OXA-232 and one produced OXA-181. The blaOXA-232 gene in all strains was located in a 6141-bp ColKP3-type non-conjugative plasmid and the blaOXA-181 gene was located in a 51,391-bp ColKP3/IncX3-type non-conjugative plasmid. The blaOXA-232-producing K. pneumoniae was dominated (75/76) by isolates of sequence type 15 (ST15) that differed by less than 80 SNPs. All OXA-producing strains (100%, 95% CI: 95.4–100.0%) were multidrug-resistant. Conclusions: From 2018 to 2021, OXA-232 is the most prevalent OXA-48-like derivative in Zhejiang Province, and ST15 K. pneumoniae isolates belonging to the same clone are the major carriers. The transmission of ColKP3-type plasmid to E. coli highlighted that understanding the transmission mechanism is of great importance to delay or arrest the propagation of OXA-232 to other species. [ABSTRACT FROM AUTHOR]

Ceftazidime-avibactam (CAV) is a new treatment option against carbapenem-resistant Klebsiella pneumoniae (CRKP) infections. However, the rapid emergence of CAV resistance mediated by KPC variants has posed a severe threat to healthcare after its clinical application. The characteristics of CAV resistance in CRKP strains needs to be determined in China. A total of 477 CRKP isolates were collected from 46 hospitals in Zhejiang Province from 2018 to 2021. The results demonstrated that CAV had a potent activity against 94.5% of all CRKP (451/477, 95% CI: 93.0–96.1%) and 86.0% of CRKP strains carrying blaKPC genes (410/477, 95% CI: 83.5–88.4%). A total of 26 CAV-resistant strains were found. Among these strains, sixteen harbored metallo-β lactamases, and two carried KPC-2 carbapenemase and mutated ompK35 and ompK36. Eight CRKP strains encoded KPC-33 or KPC-93, belonging to ST11, among which seven strains were detected in patients hospitalized in 2021 after exposure to CAV and one strain was associated with intra-hospital spread. CAV is a potent agent in vitro against CRKP strains. The rapid development of CAV resistance mediated by various KPC variants after a short period of CAV treatment has increased and brought difficulties in treating infections caused by CRKP strains, especially those belonging to ST11. The surveillance of bacterial resistance against CAV is highly recommended due to the steep development of CAV resistance and rapid evolution of KPC enzymes. [ABSTRACT FROM AUTHOR]