Purpose:
Acinetobacter baumannii is Gram-negative coccobacilli that is considered as a pathogen of a wide range of nosocomial infections. Molecular typing can distinguish suspicious and rapidly growing bacterial strains from serious outbreaks. MLVA is a molecular typing method for sub classifying microbial isolates based on variable copy number and number of consecutive repeats. Therefore, the aim of this study was to investigate the genomic polymorphism of Acinetobacter baumannii isolated from clinical samples by MLVA.
Methods:
In this study, 60 isolates of Acinetobacter baumannii were collected from clinical sources and obtained from the Pasargard Microbiology Laboratory. Gram staining and biochemical tests were performed to confirm the microbial bank, and the genomic DNA of the isolates was extracted using a kit. PCR was performed to identify regions of repetitive sequences with seven pairs of primers. After data collection and electrophoresis, a phylogenetic tree was drawn using PHYLOViZ software. A significance level of P<0.05 was considered using SPSS 22 software.
Results:
Among the 60 study isolates, 9 clusters were obtained, of which clusters A and C had the most members (each with 9 members) and were the most diverse clades. In this study, 6 clonal complexes (CC) were obtained, of which CCVI had the most diversity of strains. Based on the Simpson index and Shanus index, the closer the diversity index is to one, the better the marker is for separating isolates. The genetic diversity of each of the four markers indicates that the Ms-07 and Ms-23 markers with Simpson index of 0.9 and Shanus entropy of 3.4 were the best markers for separating 60 Acinetobacter baumannii isolates.
Conclusion:
The diverse lineage of Acinetobacter baumannii in the present study highlights the need to design an adequate surveillance program based on the main circulating clone and select the appropriate treatment. Continuous investigation and follow-up of different lineages to find antibiotic resistance patterns is recommended. The results of the present study encourage pharmaceutical companies to design new antibiotics. Considering the growing resistance in Acinetobacter baumannii, control and monitoring of drug use in Acinetobacter baumannii infections should be considered in order to control the spread of new resistances.