Molecular typing of multi-drug resistant Acinetobacter baumannii isolates from clinical and environmental specimens in three Iranian hospitals by pulsed field gel electrophoresis

Abstract

Background: Multi-drug resistant (MDR) Acinetobacter baumannii is one of the most important causes of nosocomial infections. The purpose of this study was to identify antibiotic resistance patterns, biofilm formation and the clonal relationship of clinical and environmental isolates of A. baumannii by Pulsed Field Gel Electrophoresis method. Forty-three clinical and 26 environmental isolates of the MDR A. baumannii were collected and recognized via API 20NE. Antibiotic resistance of the isolates was assessed by the disk diffusion method, and the biofilm formation test was done by the microtiter plate method. Pulsed Field Gel Electrophoresis (PFGE) was used to assess the genomic features of the bacterial isolates. Results: The resistance rate of clinical and environmental isolates against antibiotics were from 95 to 100%. The difference in antibiotic resistance rates between clinical and environmental isolates was not statistically significant (p > 0.05). Biofilm production capabilities revealed that 31 (44.9%), and 30 (43.5%) isolates had strong and moderate biofilm producer activity, respectively. PFGE typing exhibited eight different clusters (A, B, C, D, E, F, G, and H) with two significant clusters included A and G with 21 (30.4%) and 16 (23.2%) members respectively, which comprises up to 53.6% of all isolates. There was no relationship between biofilm formation and antibiotic resistance patterns with PFGE pulsotypes. Conclusions: The results show that there is a close relationship between environmental and clinical isolates of A. baumannii. Cross-contamination is also very important that occurs through daily clinical activities between environmental and clinical isolates. Therefore, in order to reduce the clonal contamination of MDR A. baumannii environmental and clinical isolates, it is necessary to use strict infection control strategies.

Genomic analysis uncovers laccase-coding genes and biosynthetic gene clusters encoding antimicrobial compounds in laccase-producing Acinetobacter baumannii

“…Strain NI-65 was isolated from community forest soil. Although high resistance rates of A. baumannii environmental isolates against most antibiotics has been reported 15 , NI-65 was determined to be an antibiotic-sensitive strain, and only two intrinsic antibiotic resistance genes ( bla OXA-51 and bla ADC-25 ) were identified. Biofilm formation and iron acquisition genes, which have been shown to be involved in the pathogenesis of most clinical A. baumannii isolates worldwide, were identified in NI-65.…”

Beta-lactamase determinants and molecular typing of carbapenem-resistant classic and hypervirulent Klebsiella pneumoniae clinical isolates from southwest of Iran

“…These results were in accordance with previous reports by Sedighi et al (2020) from Hamadan, Iran and Abdelhamid et al (2020) from Egypt. For genotyping of bacteria including K. pneumoniae isolates, several expensive and time-consuming molecular methods such as pulsed-field gel electrophoresis (PFGE), multiple locus sequence typing (MLST), and ribotyping are available ( Mohammadi Bardbari et al, 2020 ; Sedighi et al, 2020 ). However, ERIC-PCR method is an inexpensive, reliable, and fast molecular method for genotyping of Enterobacteriaceae family ( Sedighi et al, 2020 ).…”

Molecular typing and antibiotic resistance patterns among clinical isolates of Acinetobacter baumannii recovered from burn patients in Tehran, Iran

“…In 2006, all strains isolated in Iran were susceptible to tigecycline, but between 2011 and 2014, resistance to this antibiotic increased ( Taheri et al, 2022 ). In a study conducted by Mohammadi Bardbari et al in Iran, all clinical and environmental isolates of A. baumannii were sensitive to colistin and tigecycline ( Mohammadi Bardbari et al, 2020 ). Rahimi et al in Iran examined 80 isolates, 100% sensitive to colistin, and 6% resistant to tigecycline ( Rahimi et al, 2018 ).…”