Clinical distribution and antibiotics resistance mechanisms of non-baumannii Acinetobacter

Objective To analyze the clinical distribution characteristics and drug sensitivity of non-baumannii Acinetobacter(NbA) isolates, and to detect metallo-β-lactamases and integrase genes. Methods K-B method was used to test the drug sensitivity of non-baumannii Acinetobacter isolated from various specimens collected from wards and clinics of two teaching hospitals in Anhui Province. The results were judged according to CLSI 2016 edition. Polymerase chain reaction(PCR) was used to amplify the metallo-β-lactamase gene and the integrase gene of class Ⅰ-Ⅲ integrin. Results Total 44 NbA isolates(29 A. lwoffii strains, 9 A. junii strains, 2 A. haemolyticus strains, 3 A. calcoaceticus strains and 1 Acinetobacter genomic species 13 TU strain) were potentially gathered in Cardiology Department, Respiratory Department and others, and isolated from sputum, urine, secretion and other samples. Three(6.8%) isolates(2 A. lwoffii strains, 1 A. haemolyticus strain) were multi-resistant, 17 strains(38.6%) were susceptible to all antimicrobial agents except β-lactam antibiotics, while the rest 24 isolates were fully susceptible. Nine of the 44(20.45%) NbA isolates carried SIM-1 gene, including 7 A. lwoffii strains and 2 A. junii strains. Four strains(9.09%) carried VIM-2 gene, including 2 A. lwoffii strains, 1 A. haemolyticus strain and 1 A. junii strain. IMP-4, NDM-1 gene were not detected in all NbA strains. Five(11.36%) harbored Class 1 integrase, including 3 A. lwoffii strains, 1 A. haemolyticus strain and 1 A. junii strain, 6(13.64%) isolates harbored class 2 integrase, including 3 A. lwoffii strains, 1 A. haemolyticus strain and 2 A. junii strains. No class 3 integrase were found in all the NbA isolates. Conclusion The drug resistance rate of non-baumannii Acinetobacter is relatively low, but multidrug-resistant strains have been found. The mechanism of drug resistance may be related to metallo-β-lactamase and integrase.