The Role of blaOXA-101 and blaOXA-573 in Extensively Drug-Resistant/ Pan Drug-Resistant (XDR/PDR) Pseudomonas aeruginosa Resistance to Ceftazidime-Avibactam

Yixin Kang,1,2 Junchang Cui1,2 1Nankai University, Tianjin, People’s Republic of China; 2College of Pulmonary & Critical Care Medicine, The Eighth Medical Center, Chinese PLA General Hospital, Beijing, People’s Republic of ChinaCorrespondence: Junchang Cui, College of Pulmonary & Critical Care Medicine, The Eighth Medical Center, Chinese PLA General Hospital, 17A Heishanhu Road, Haidian District, Beijing, 100091, People’s Republic of China, Email [email protected]: To explore the association of the resistance of extensively drug-resistant/ pan-drug-resistant Pseudomonas aeruginosa (XDR/PDR-PA) to ceftazidime-avibactam (CZA) with various class D β-lactamase genes.Methods: Twofold dilution was used to determine the minimum inhibitory concentration (MIC) of CZA against XDR/PDR-PA. Whole genome sequencing and bioinformatics analysis were used to determine the drug-resistant genes of each isolate. Pearson correlation coefficient and statistical analysis were used to assess the association of the resistance of XDR/PDR-PA to CZA and various class D β-lactamase genes.Results: ST244 was the predominant type (34/68, 50%) among the 68 XDR/PDR-PA strains. Subsequently, ST357 was the second most prevalent type (5/68, 7.4%) strain. blaOXA-101 and blaOXA-573 genes were associated with resistance to CZA (p-value was 0.029 and 0.021, respectively) in the 68 XDR/PDR-PA isolates tested.Conclusion: Our work found that blaOXA-101 and blaOXA-847 play a role in XDR/PDR-PA resistance to CZA.Keywords: P. aeruginosa, β-lactamases, ceftazidime–avibactam