Molecular typing, and integron and associated gene cassette analyses in Acinetobacter baumannii strains isolated from clinical samples

Abstract

The present study aimed to investigate the association between drug resistance and class I, II and III integrons in Acinetobacter baumannii (ABA). Multilocus sequence typing (MLST) is a tool used to analyze the homology among house-keeping gene clusters in ABA and ABA prevalence and further provides a theoretical basis for hospitals to control ABA infections. A total of 96 clinical isolates of non-repeating ABA were harvested, including 74 carbapenem-resistant ABA (CRABA) and 22 non-CRABA strains, and used for bacterial identification and drug susceptibility analysis. Variable regions were sequenced and analyzed. Then, 7 pairs of housekeeping genes were amplified and sequenced via MLST and sequence alignment was performed against the Pub MLST database to determine sequence types (STs) strains and construct different genotypic evolutionary diagrams. The detection rate of CRABA class I integrons was 13.51% (10/74); no class II and III integrons were detected. However, class I, II and III integrons were not detected in non-CRABA strains. The variable regions of 9 of 10 class I integrons were amplified and 10 gene cassettes including aacC1, aac1, aadDA1, aadA1a, aacA4, dfrA17, aadA5, aadA1, aadA22 and aadA23 were associated with drug resistance. The 96 ABA strains were divided into 21 STs: 74 CRABA strains containing 9 STs, primarily ST208 and ST1145 and 22 non-CRABA strains containing 18 STs, primarily ST1145. Class I integrons are a critical factor underlying drug resistance in ABA. CRABA and non-CRABA strains differ significantly; the former primarily contained ST208 and ST1145, and the latter contained ST1145. Most STs were concentrated in intensive care units (ICUs) and the department of Neurology, with the patients from the ICUs being the most susceptible to bacterial infection. In the Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, ABA is potentially horizontally transmitted and MLST can be used for clinical ABA genotyping.

Local characteristics of molecular epidemiolgy of Acinetobacter baumannii in Jilin province (northeast China)

“…According to the published articles about A. baumannii research in China [8,[11][12][13][14][15][16][17], epidemic STs in Jilin appeared earlier than non-epidemic STs in Jilin. But in Jilin isolates, some major Chinese STs in CC92 group were not founded, such as ST191 (Beijing and Hunan) [18,19] and ST1145 (Guangdong) [20]. And the epidemic ST92, which was predicted to be the group founder of CC92 group, was never found in Jilin province too.…”

Local characteristics of molecular epidemiolgy of Acinetobacter baumannii in Jilin Province (northeast China)

“…And the causative pathogen could be identi ed quickly and infection prevention and control measures could be applied earlier if daily routine molecular typing is implemented [4]. [20]. And the epidemic ST92, which was predicted to be the group founder of CC92 group, was never found in Jilin province too.…”

Synergistic Effects of a Probiotic Culture Extract and Antimicrobial Combinations against Multidrug-Resistant Acinetobacter baumannii

“…Multi-locus sequence typing (MLST) analysis was utilized to elucidate gene diversity and structural correlations in the A. baumannii strains using seven structural genes from the Oxford housekeeping gene group. Polymerase chain reaction was performed using a solution (50 µL) consisting of 1.25 U of TaKaRa Ex Taq TM , 2 × buffer (25 mM TAPS, 50 mM KCl, 2 mM MgCl 2 , 1 mM 2-mercaptoethanol), 0.4 mM of dNTPs mixture, 1 µL of 10 pM primer, and 10 ng of pure isolated chromosomal DNA [18,19]. Sequencing was performed on the resultant amplicons and results were analyzed using the public databases for molecular typing and microbial genome diversity (https://pubmlst.org/ accessed on 14 November 2021) to confirm the final sequence types (STs) of A. baumannii.…”