Genes involved in colistin resistance of gram-negative isolates in the northwest of Iran

Aghapour, Zahra; Hasani, Alka; Aghazadeh, Mohammad; Rezaee, Mohammad Ahangarzadeh; Ganbarov, Khudaverdi; Pourlak, Tala; Gholizadeh, Pourya; Asgharzadeh, Mohammad; Tanomand, Asghar; Kafil, Hossein Samadi

doi:10.1016/j.genrep.2018.12.001

Cited by 11 publications

(13 citation statements)

References 28 publications

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“…The prevalence of mcr in our study was 2.6%, similar to an earlier report, which showed a prevalence in Pakistan of 2.8% [ 18 ]. The findings of studies performed in other countries correspond well with those of our study, with studies in Iran and India reporting mcr rates among clinical isolates of 3% and 3.2%, respectively [ 19 , 20 ]. The mcr-1 gene is most commonly found in E. coli compared with other bacterial species globally [ 21 , 22 ].…”

Section: Discussionsupporting

confidence: 91%

Molecular Epidemiology of Extensively Drug-Resistant mcr Encoded Colistin-Resistant Bacterial Strains Co-Expressing Multifarious β-Lactamases

et al. 2021

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Plasmid-mediated colistin resistance (Col-R) conferred by mcr genes endangers the last therapeutic option for multifarious β-lactamase-producing bacteria. The current study aimed to explore the mcr gene molecular epidemiology in extensively drug-resistant (XDR) bacteria. Col-R gram-negative bacterial strains were screened using a minimum inhibitory concentration (MIC) breakpoint ≥4 µg/mL. Resistant isolates were examined for mcr variants, extended-spectrum β-lactamase, AmpC, and carbapenemase genes using polymerase chain reaction (PCR). The MIC breakpoints for mcr-positive strains were determined using broth microdilution and E-test strips. Overall, 19/718 (2.6%) gram-negative rods (GNRs) harboring mcr were identified, particularly in pus (p = 0.01) and tracheal secretions (p = 0.03). Molecular epidemiology data confirmed 18/19 (95%) mcr-1 and 1/19 (5%) mcr-2 genes. Integron detection revealed 15/17 (88%) Int-1 and 2/17 (12%) Int-2. Common co-expressing drug-resistant β-lactamase genes included 8/16 (50%) blaCTM-1, 3/16 (19%) blaCTM-15, 3/3 (100%) blaCMY-2, 2/8 (25%) blaNDM-1, and 2/8 (25%) blaNDM-5. The MIC50 and MIC90 values (µg/mL) were as follows: Escherichia coli, 12 and 24; Klebsiella pneumoniae, 12 and 32; Acinetobacter baumannii, 8 and 12; and Pseudomonas aeruginosa, 32 and 64, respectively. Treatment of XDR strains has become challenging owing to the co-expression of mcr-1, mcr-2, multifarious β-lactamase genes, and integrons.

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Section: Discussionsupporting

confidence: 91%

Molecular Epidemiology of Extensively Drug-Resistant mcr Encoded Colistin-Resistant Bacterial Strains Co-Expressing Multifarious β-Lactamases

et al. 2021

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“…Another study from southwest Iran reported 1.2% of E. coli and 0.4% of K. pneumoniae isolates from human samples carried mcr-1 gene while mcr-2 was not detected [26]. Consistently, in a recent study, no mcr-1 and mcr-2 genes were identified from Enterobacteriaceae isolates of human origin in the northwest of Iran [27]. Despite the regular administration of colistin in farm animals, the absence of mcr-1 and mcr-2 genes suggested that these genes were not widespread among animal sources in Iran at least until few years ago.…”

Section: Resultsmentioning

confidence: 62%

Molecular survey of mcr1 and mcr2 plasmid mediated colistin resistance genes in Escherichia coli isolates of animal origin in Iran

et al. 2021

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Objectives The emergence of colistin-resistant Enterobacteriaceae from human and animal sources is one of the major public health concerns as colistin is the last-resort antibiotic for treating infections caused by multidrug-resistant Gram-negative bacteria. We aimed to determine the prevalence of the prototype widespread colistin resistance genes (mcr-1 and mcr-2) among commensal and pathogenic Escherichia coli strains isolated from food-producing and companion animals in Iran. Results A total of 607 E. coli isolates which were previously collected from different animal sources between 2008 and 2016 used to uncover the possible presence of plasmid-mediated colistin resistance genes (mcr-1 and mcr-2) by PCR. Overall, our results could not confirm the presence of any mcr-1 or mcr-2 positive E. coli among the studied isolates. It is concluded that despite the important role of food-producing animals in transferring the antibiotic resistance, they were not the main source for carriage of mcr-1 and mcr-2 in Iran until 2016. This study suggests that the other mcr variants (mcr-3 to mcr-9) might be responsible for conferring colistin resistance in animal isolates in Iran. The possible linkage between pig farming industry and high level of mcr carriage in some countries needs to be clarified in future prospective studies.

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“…Only one mechanism of resistance has been identified as a transferable mechanism (plasmid-mediated mcr gene) so far (Table 1). 9,21…”

Section: Mechanisms Of Colistin Resistance In Enterobacteriaceaementioning

confidence: 99%

“…On the other hand, the phoPQ TCS encodes PhoP as a regulator protein and PhoQ as a sensor kinase. Under conditions of low magnesium or calcium, acidic PH, or cationic antimicrobial peptide, PhoPQ is activated and protects bacteria 21,63,64. Activated PhoPQ leads to modification of lipid A via two routes: PhoQ activates PhoP by its kinase activity via phosphorylation, which activates transcription of the pmrFHIJKLM operon, followed by modification of lipid A;70,71 and PhoP indirectly activates pmrA by bypassing the PmrD connector protein, subsequently activates the transcription of the pmrHFIJKLM operon and synthesizes PETN, which transfers it to lipid A 72,73…”

Section: Mechanisms Of Colistin Resistance In Enterobacteriaceaementioning

confidence: 99%

“…Unfortunately, during the last few decades, the emergence of colistin-resistant isolates has been frequently reported,10,12 which has increased inappropriate use of this drug, especially as monotherapy could be the cause of this problem 16–18. In addition, there have been reports of increased infection due to bacteria with intrinsic resistance to colistin, such as Proteus spp., Providencia spp., Serratia spp., and Morganella spp 19–21. In this article, we assess different mechanisms of colistin resistance in Enterobacteriaceae.…”

Section: Introductionmentioning

confidence: 99%

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<p>Molecular mechanisms related to colistin resistance in Enterobacteriaceae</p>

Aghapour

Gholizadeh

Ganbarov

et al. 2019

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Colistin is an effective antibiotic for treatment of most multidrug-resistant Gram-negative bacteria. It is used currently as a last-line drug for infections due to severe Gram-negative bacteria followed by an increase in resistance among Gram-negative bacteria. Colistin resistance is considered a serious problem, due to a lack of alternative antibiotics. Some bacteria, including Pseudomonas aeruginosa , Acinetobacter baumannii , Enterobacteriaceae members, such as Escherichia coli, Salmonella spp., and Klebsiella spp. have an acquired resistance against colistin. However, other bacteria, including Serratia spp., Proteus spp. and Burkholderia spp. are naturally resistant to this antibiotic. In addition, clinicians should be alert to the possibility of colistin resistance among multidrug-resistant bacteria and development through mutation or adaptation mechanisms. Rapidly emerging bacterial resistance has made it harder for us to rely completely on the discovery of new antibiotics; therefore, we need to have logical approaches to use old antibiotics, such as colistin. This review presents current knowledge about the different mechanisms of colistin resistance.

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Genes involved in colistin resistance of gram-negative isolates in the northwest of Iran

Cited by 11 publications

References 28 publications

Molecular Epidemiology of Extensively Drug-Resistant mcr Encoded Colistin-Resistant Bacterial Strains Co-Expressing Multifarious β-Lactamases

Molecular Epidemiology of Extensively Drug-Resistant mcr Encoded Colistin-Resistant Bacterial Strains Co-Expressing Multifarious β-Lactamases

Molecular survey of mcr1 and mcr2 plasmid mediated colistin resistance genes in Escherichia coli isolates of animal origin in Iran

<p>Molecular mechanisms related to colistin resistance in Enterobacteriaceae</p>

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