Prevalence and molecular mechanisms of colistin resistance in Acinetobacter baumannii clinical isolates in Tehran, Iran

Khoshbayan, Amin; Shariati, Aref; Shahmoradi, Samane; Baseri, Zohre; Mozafari, Haniyeh; Darban-Sarokhalil, Davood

doi:10.1556/030.2021.01420

Cited by 12 publications

(9 citation statements)

References 25 publications

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“…Furthermore, the phenotype was defined as MDR based on the International Expert proposal for Interim Standards Guidelines. For colistin-resistant (ColR) isolates further susceptibility testing was performed using the disk diffusion method for ciprofloxacin (5 mg), nitrofurantoin (300 mg), gentamicin (10 mg), norfloxacin (10 mg), trimethoprim/sulfamethoxazole (25 mg), chloramphenicol (30 mg), cefixime (5 mg), tetracycline (30 mg), and ampicillin (10 mg) [19,23,24].…”

Section: Antimicrobial Susceptibility Testingmentioning

confidence: 99%

Mutation in mgrB is the major colistin resistance mechanism in Klebsiella pneumoniae clinical isolates in Tehran, Iran

Khoshbayan

Shariati

Razavi

et al. 2022

AMicr

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Colistin is considered as one of a last resort antimicrobial agent against multidrug-resistant Gram-negative bacteria including Escherichia coli and Klebsiella pneumoniae. However, the recent emergence of colistin resistance (ColR) worldwide that severely restricts therapeutic options is a serious threat to global public health. In this study we have investigated the molecular determinants in ColR K. pneumoniae isolates collected from clinical specimens. A total of 98 E. coli and 195 K. pneumoniae clinical isolates were collected from two hospitals from August 2018 to December 2019 in Tehran, Iran. Colistin susceptibility and minimum inhibitory concentrations (MIC) were determined according to the Clinical and Laboratory Standards Institute by disk diffusion method, and microdilution method, respectively. For isolates with colistin MIC ≥4 μg mL−1, PCR was performed for the detection of mcr-1 to mcr-4 genes. Moreover, nucleotide sequences of mgrB, phoP, phoQ, pmrA, and pmrB genes were determined by sequencing. Finally, the transcriptional level of pmrK and pmrC genes was evaluated by quantitative reverse transcription PCR (RT-qPCR). None of the E. coli isolates were resistant to colistin while 21 out 195 K. pneumoniae isolates were identified as resistant, 19 of which carried mutation in the mgrB gene. Three different mutations were observed in the pmrB gene in 3 K. pneumoniae isolates. None of the ColR isolates showed alternations in pmrA, phoP, and phoQ genes. Furthermore, none of the plasmid-encoding genes were detected. Transcriptional level of the pmrK gene increased in all ColR isolates meanwhile, pmrC overexpression was detected in 16 out 21 (76.19%) isolates. Eventually, all ColR isolates were susceptible to tigecycline. Our results demonstrated that the alternation of mgrB gene is the main mechanism related to colistin resistance among ColR K. pneumoniae isolates in this study.

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Section: Antimicrobial Susceptibility Testingmentioning

confidence: 99%

Mutation in mgrB is the major colistin resistance mechanism in Klebsiella pneumoniae clinical isolates in Tehran, Iran

Khoshbayan

Shariati

Razavi

et al. 2022

AMicr

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“…Clinical isolates from Egypt report a very high rate at 49% [37], whereas Saudi Arabia showed 8.5% prevalence [38]. Contrastingly, countries like Serbia (3.94%) [39] and Iran (2.8%) [40,41] have shown lower prevalence of Col R A. baumannii . A 2024 meta-analysis using the broth microdilution (BMD) method determined a global pooled prevalence of Col R in A. baumannii at 4% [42].…”

Section: Discussionmentioning

confidence: 99%

Colistin resistance among the Gram-negative nosocomial pathogens in India: A systematic review and meta-analysis

Dwibedy,

Padhy,

Panda

et al. 2024

Preprint

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Background The rapid rise of nosocomial infections and the growing ineffectiveness of frontline antibiotics against Gram-negative bacteria (GNB) have put the healthcare sector under unprecedented stress. In this scenario, colistin, an antibiotic of the polymyxin class, has become the last resort treatment option. The unrestricted use of colistin in the preceding decades has led to the emergence of colistin-resistant (ColR) bacterial strains. Unfortunately, comprehensive data on the prevalence of ColR nosocomial pathogens in India are lacking. This study was conducted to address this information gap and to determine the prevalence of ColR among the nosocomial GNB species in India. Methods A systematic review and meta-analysis were conducted to determine the prevalence of ColR among the nosocomial GNB species in India and their geographical distribution. A systematic search of the online databases was performed and eligible studies meeting the inclusion criteria were used for qualitative synthesis. The combined event rate and 95% confidence interval were estimated using forest plot with a random-effect model. Cochrane Q statistics and I2 statistics were used to detect possible heterogeneity. Results From a total of 1865 retrieved records from 4 databases, 36 studies were included in the study. Among the most common nosocomial pathogens, K. pneumoniae showed a rate of ColR at 17.4%, followed by P. aeruginosa (14.1%), E. coli (12.3%), and A. baumannii (12.2%). Interestingly, our analysis revealed that E. cloacae has the highest rate of ColR at 28.5%. Conclusions The level of resistance displayed by K. pneumoniae, P. aeruginosa, and to a lesser extent, E. coli and A. baumannii in the Indian subcontinent poses a challenge for public health management. Though prevalence may differ among regions and over time, continued surveillance, and efforts to curb the spread of resistance are crucial to ensure the continued effectiveness of this critical antibiotic.

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“…For each isolate tested, a positive and negative control were included in the first and second wells of the plate, respectively. E. coli ATCC 25922 was used as a standard control strain [23].…”

Section: Methodsmentioning

confidence: 99%

Zinc oxide nanoparticles impact the expression of the genes involved in toxin–antitoxin systems in multidrug‐resistant Acinetobacter baumannii

et al. 2022

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The aim of this study was to investigate the effect of zinc oxide nanoparticles (ZnO‐NPs) on the expression of genes involved in toxin–antitoxin (TA) systems in multidrug‐resistant (MDR) Acinetobacter baumannii. Seventy clinical isolates of A. baumannii were collected from variuos clinical samples. Antimicrobial susceptibility test was determined by disk diffusion. Type II TA system‐related genes including GNAT, XRE‐like, hipA, hipB, hicA, hicB were screened using polymerase chain reaction (PCR). ZnO‐NPs prepared and characterized by field emission scanning electron microscopy and X‐ray diffraction. MIC of ZnO‐NPs of A. baumannii isolates was performed using the microdilution method. The expression of type II TA systems‐related genes were assessed with and without exposure to ZnO‐NPs using real‐time PCR. The highest rate of resistance and sensitivity was observed against cefepime (77.14%), and ampicillin/sulbactam (42.85%), respectively. All A. baumannii isolates were considered as MDR. In this study, three TA loci were identified for A. baumannii including GNAT/XRE‐like, HicA/HicB, and HipA/HipB and their prevalence was 100%, 42%, and 27.1%, respectively. There was no significant relationship between the prevalence of these systems and the origin of A. baumannii. Our data showed significant correlations between the presence of HicA/HicB system and resistance to ceftazidime, meropenem, imipenem, and cefepime (p < 0.05), and the presence of HipA/HipB system and resistance to ceftazidime, meropenem, imipenem, and cefepime (p < 0.05). In presence of ZnO‐NPs, the expression of all studied genes decreased. GNAT and hicB showed the highest and lowest expression changes by 2.4 folds (p < 0.001) and 1.3 folds (p < 0.05), respectively. This study demonstrates the promising potential of nanoparticles to impact the expression of the genes involved in TA Systems. So, the application of ZnO‐NPs may be helpful to design target‐based strategies towards MDRs pathogens for empowered clinical applications by microbiologists and nanotechnologists.

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Prevalence and molecular mechanisms of colistin resistance in Acinetobacter baumannii clinical isolates in Tehran, Iran

Cited by 12 publications

References 25 publications

Mutation in mgrB is the major colistin resistance mechanism in Klebsiella pneumoniae clinical isolates in Tehran, Iran

Mutation in mgrB is the major colistin resistance mechanism in Klebsiella pneumoniae clinical isolates in Tehran, Iran

Colistin resistance among the Gram-negative nosocomial pathogens in India: A systematic review and meta-analysis

Zinc oxide nanoparticles impact the expression of the genes involved in toxin–antitoxin systems in multidrug‐resistant Acinetobacter baumannii

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