Association of virulence gene expression with colistin-resistance in Acinetobacter baumannii: analysis of genotype, antimicrobial susceptibility, and biofilm formation

Bahador, Abbas; Farshadzadeh, Zahra; Raoofian, Reza; Mokhtaran, Masoumeh; Pourakbari, Babak; Pourhajibagher, Maryam; Hashemi, Farhad B.

doi:10.1186/s12941-018-0277-6

Cited by 22 publications

(23 citation statements)

References 48 publications

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“…The predominance of IC II was in good agreement with previous reports from Japan 52 and Brazil 53 that recognized the IC II as the most common clone in A. baumannii isolates. Meanwhile, the prevalence of IC I with 11.4% frequency rate was lower than the frequency rate (19%) stated by Bahador et al 54 in Tehran, Iran. Another difference between this and that study was the strong biofilm production by the majority of our CI I and CI II lineages, while in the Bahador's study, 54 they were moderate biofilm producers.…”

Section: Discussioncontrasting

confidence: 56%

“…Meanwhile, the prevalence of IC I with 11.4% frequency rate was lower than the frequency rate (19%) stated by Bahador et al 54 in Tehran, Iran. Another difference between this and that study was the strong biofilm production by the majority of our CI I and CI II lineages, while in the Bahador's study, 54 they were moderate biofilm producers.…”

Section: Discussioncontrasting

confidence: 56%

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Survey on Genetic Diversity, Biofilm Formation, and Detection of Colistin Resistance Genes in Clinical Isolates of Acinetobacter baumannii

Khoshnood¹,

Savari²,

Montazeri³

et al. 2020

IDR

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Introduction: Acinetobacter baumannii is an opportunistic pathogen responsible for nosocomial infections. The emergence of colistin-resistant A. baumannii is a significant threat to public health. The aim of this study was to investigate the molecular characterization and genotyping of clinical A. baumannii isolates in Southwestern Iran. Methods: A total of 70 A. baumannii isolates were collected from patients admitted to Imam Khomeini Hospital in Ahvaz, Southwestern Iran. Minimum inhibitory concentration test was conducted by using Vitek 2 system. The presence of biofilm-forming genes and colistin resistance-related genes were evaluated by PCR. The isolates were also examined for their biofilm formation ability and the expression of pmrA and pmrB genes. Finally, multilocus sequence typing (MLST) and PCR-based sequence group were used to determine the genetic relationships of the isolates. Results: Overall, 61 (87.1%) and 9 (12.8%) isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR), respectively. Colistin and tigecycline with 2 (2.8%) and 32 (45.7%) resistance rates had the highest effect. Among all the isolates, 55 (78.5%), 7 (10%), and 3 (4.3%) were strong, moderate, and weak biofilm producers, respectively. The frequency rates of biofilm-related genes were 64 (91.4%), 70 (100%), 56 (80%), and 22 (31.42%) for bap, ompA, csuE, and bla PER1 , respectively. Overexpression of pmrA and pmrB genes was observed in two colistin-resistance isolates, but the expression of these genes did not change in colistin-sensitive isolates. Additionally, 37 (52.8%) and 8 (11.4%) isolates belonged to groups 1 (ICII) and 2 (IC I), respectively. MLST analysis revealed a total of nine different sequence types that six isolates belonged to clonal complex 92 (corresponding to ST801, ST118, ST138, ST 421, and ST735). Other isolates were belonging to ST133 and ST216, and two colistin-resistant (Ab4 and Ab41) isolates were belonging to ST387 and ST1812. Conclusion: The present study revealed the presence of MDR and XDR A. baumannii isolates harboring biofilm genes and emergence of colistin-resistant isolates in Southwestern Iran. These isolates had high diversity, which was affirmed by typing techniques. The control measures and regular surveillance are urgently needed to preclude the spread of these isolates.

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Section: Discussioncontrasting

confidence: 56%

Section: Discussioncontrasting

confidence: 56%

Survey on Genetic Diversity, Biofilm Formation, and Detection of Colistin Resistance Genes in Clinical Isolates of Acinetobacter baumannii

Khoshnood¹,

Savari²,

Montazeri³

et al. 2020

IDR

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“…This theory is partly supported by the fact that the over expression of MexAB-OprM and MexXY-OprM efflux pumps has already been linked to resistance in P. aeruginosa in multiple antimicrobial agents such as aminoglycosides (Hocquet et al, 2003). One interesting study done by Bahador et al (2018) found that resistance to colistin in A. baumannii isolates is linked to the increase in virulence factors such as biofilm formation in burn patients. This renders the treatment of such MDR more challenging, as both resistance to colistin and virulence factors must be tackled at once (Bahador et al, 2018).…”

Section: Distribution Of Multi-drug Resistant Organisms In Humansmentioning

confidence: 99%

“…One interesting study done by Bahador et al (2018) found that resistance to colistin in A. baumannii isolates is linked to the increase in virulence factors such as biofilm formation in burn patients. This renders the treatment of such MDR more challenging, as both resistance to colistin and virulence factors must be tackled at once (Bahador et al, 2018). Furthermore, two studies reported the isolation of colistin resistant A. baumannii and K. pneumoniae with mutations in the pmrB and mgrB genes, respectively (Haeili et al, 2017, 2018) (Table 3).…”

Section: Distribution Of Multi-drug Resistant Organisms In Humansmentioning

confidence: 99%

Understanding the Epidemiology of Multi-Drug Resistant Gram-Negative Bacilli in the Middle East Using a One Health Approach

et al. 2019

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In the last decade, extended-spectrum cephalosporin and carbapenem resistant Gram-negative bacilli (GNB) have been extensively reported in the literature as being disseminated in humans but also in animals and the environment. These resistant organisms often cause treatment challenges due to their wide spectrum of antibiotic resistance. With the emergence of colistin resistance in animals and its subsequent detection in humans, the situation has worsened. Several studies reported the transmission of resistant organisms from animals to humans. Studies from the middle east highlight the spread of resistant organisms in hospitals and to a lesser extent in livestock and the environment. In view of the recent socio-economical conflicts that these countries are facing in addition to the constant population mobilization; we attempt in this review to highlight the gaps of the prevalence of resistance, antibiotic consumption reports, infection control measures and other risk factors contributing in particular to the spread of resistance in these countries. In hospitals, carbapenemases producers appear to be dominant. In contrast, extended spectrum beta lactamases (ESBL) and colistin resistance are becoming a serious problem in animals. This is mainly due to the continuous use of colistin in veterinary medicine even though it is now abandoned in the human sphere. In the environment, despite the small number of reports, ESBL and carbapenemases producers were both detected. This highlights the importance of the latter as a bridge between humans and animals in the transmission chain. In this review, we note that in the majority of the Middle Eastern area, little is known about the level of antibiotic consumption especially in the community and animal farms. Furthermore, some countries are currently facing issues with immigrants, poverty and poor living conditions which has been imposed by the civil war crisis. This all greatly facilitates the dissemination of resistance in all environments. In the one health concept, this work re-emphasizes the need to have global intervention measures to avoid dissemination of antibiotic resistance in humans, animals and the environment in Middle Eastern countries.

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“…6 There are now reports from different regions of the world of pan-drug-resistant (PDR) A. baumannii. 7 The primary resistance mechanism is mediated through the modification of the lipid A moiety of lipopolysaccharide (LPS) through the addition of phosphoethanolamine (PEtN) through overexpression and/or mutations in the two-component regulatory system PmrA and PmrB. Other mechanisms have been described and include the loss of LPS caused by either insertional inactivation of lipid A biosynthesis genes or mutations, but this appears to be limited to in-vitro studies.…”

Section: Introductionmentioning

confidence: 99%

Molecular Characterization of Carbapenem/Colistin-Resistant Acinetobacter baumannii Clinical Isolates from Egypt by Whole-Genome Sequencing

Fam¹,

Gamal²,

Mohamed³

et al. 2020

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Purpose The rise of carbapenem-resistant A. baumannii (CRAB) is considered a public health problem limiting the treatment options. Our current work studied the emergence and mechanisms of colistin-resistance among CRAB isolates in Egypt. Materials and Methods Seventeen clinically recovered A. baumannii were identified and screened for their antimicrobial susceptibilities using VITEK-2 system. Colistin susceptibility was evaluated using broth microdilution, and characterization of carbapenem/colistin resistance determinants was performed using whole-genome sequencing (Illumina MiSeq). Results About 52.9% (9/17) were colistin-resistant. PCR results revealed that all isolates carried bla OXA-51-like genes , bla OXA-23-like was detected in 82.3% (14/17) and bla NDM in 23.5% (4/17). Two isolates harboured bla GES-35 and bla OXA-23 . Furthermore, genome analysis of seven isolates revealed six belonged to international clone 2 (IC2) while the remaining isolate was a singleton (ST158), representing a clone circulating in Mediterranean/Middle Eastern countries. Conclusion The emergence and high incidence of colistin-resistance among CRAB clinical isolates in Egypt are alarming because it further limits therapy options and requires prudent antimicrobial stewardship and stringent infection control measures. Whole-genome sequence analyses suggest that the resistance to colistin was associated with multiple mutations in the pmrCAB genes. The high incidence of the high-risk lineage IC2 harbouring bla OXA-23-like as well as bla NDM is also of concern.

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Association of virulence gene expression with colistin-resistance in Acinetobacter baumannii: analysis of genotype, antimicrobial susceptibility, and biofilm formation

Cited by 22 publications

References 48 publications

<p>Survey on Genetic Diversity, Biofilm Formation, and Detection of Colistin Resistance Genes in Clinical Isolates of <em>Acinetobacter baumannii</em></p>

<p>Survey on Genetic Diversity, Biofilm Formation, and Detection of Colistin Resistance Genes in Clinical Isolates of <em>Acinetobacter baumannii</em></p>

Understanding the Epidemiology of Multi-Drug Resistant Gram-Negative Bacilli in the Middle East Using a One Health Approach

<p>Molecular Characterization of Carbapenem/Colistin-Resistant <em>Acinetobacter baumannii</em> Clinical Isolates from Egypt by Whole-Genome Sequencing</p>

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