Prevalence of Carbapenem Resistance Genes among Acinetobacter baumannii Isolated from a Teaching Hospital in Taiwan.

The problem of antibiotic-resistant strains has become a global public issue; antibiotic resistance not only limits the choice of treatments but also increases morbidity, mortality and treatment costs. The multi-drug resistant Acinetobacter baumannii is occurring simultaneously in hospitals and has become a major public health issue worldwide. Although many medical units have begun to control the use of antibiotics and paid attention to the issue of drug resistance, understanding the transmission pathways of clinical drug-resistant bacteria and drug-resistant mechanisms can be effective in real-time control and prevent the outbreak of antibiotic-resistant pathogens. In this study, a total of 154 isolates of Acinetobacter baumannii obtained from Chia-Yi Christian Hospital in Taiwan were collected for specific resistance genotyping analysis. Ten genes related to drug resistance, including bla OXA-51-like, bla OXA-23-like, bla OXA-58-like, bla OXA-24-like, bla OXA-143-like, tnp A, IS Aba 1, bla PER-1, bla NDM and bla ADC, and the repetitive element (ERIC2) were selected for genotyping analysis. The results revealed that 135 A. baumannii isolates (87.6%) carried the bla OXA-51-like gene, 4.5% of the isolates harbored the bla OXA-23-like gene, and 3.2% of the isolates carried the bla OXA-58-like gene. However, neither the bla OXA-24-like nor bla OXA-143-like genes were detected in the isolates. Analysis of ESBL-producing strains revealed that bla NDM was not found in the test strains, but 38.3% of the test isolates carried bla PER-1. In addition, bla ADC, tnp A and IS Aba 1genes were found in 64.9%, 74% and 93% of the isolates, respectively. Among the carbapenem-resistant strains of A. baumannii , 68% of the isolates presenting a higher antibiotic resistance carried both tnp A and IS Aba 1 genes. Analysis of the relationship between their phenotypes (antibiotic resistant and biofilm formation) and genotypes (antibiotic-resistant genes and biofilm-related genes) studied indicated that the bap , omp A, IS Aba 1and bla OXA-51 genes influenced biofilm formation and antibiotic resistance patterns based on the statistical results of a hierarchical clustering dendrogram. The analysis of the antibiotic-resistant mechanism provides valuable information for the screening, identification, diagnosis, treatment and control of clinical antibiotic-resistant pathogens, and is an important reference pointer to prevent strains from producing resistance.