Dataset Information

Antibiotic resistance and detection of plasmid mediated colistin resistance mcr-1 gene among Escherichia coli and Klebsiella pneumoniae isolated from clinical samples.

ABSTRACT:

Background

The prevalence of antimicrobial resistance (AMR) among Gram-negative bacteria is alarmingly high. Reintroduction of colistin as last resort treatment in the infections caused by drug-resistant Gram-negative bacteria has led to the emergence and spread of colistin resistance. This study was designed to determine the prevalence of drug-resistance among beta-lactamase-producing strains of Escherichia coli and Klebsiella pneumoniae, isolated from the clinical specimens received at a tertiary care centre of Kathmandu, Nepal during the period of March to August, 2019.

Methods

A total of 3216 different clinical samples were processed in the Microbiology laboratory of Kathmandu Model Hospital. Gram-negative isolates (E. coli and K. pneumoniae) were processed for antimicrobial susceptibility test (AST) by using modified Kirby-Bauer disc diffusion method. Drug-resistant isolates were further screened for extended-spectrum beta-lactamase (ESBL), metallo-beta-lactamase (MBL), carbapenemase and K. pneumoniae carbapenemase (KPC) production tests. All the suspected enzyme producers were processed for phenotypic confirmatory tests. Colistin resistance was determined by minimum inhibitory concentration (MIC) using agar dilution method. Colistin resistant strains were further screened for plasmid-mediated mcr-1 gene using conventional polymerase chain reaction (PCR).

Results

Among the total samples processed, 16.4% (529/3216) samples had bacterial growth. A total of 583 bacterial isolates were recovered from 529 clinical samples. Among the total isolates, 78.0% (455/583) isolates were Gram-negative bacteria. The most predominant isolate among Gram-negatives was E. coli (66.4%; 302/455) and K. pneumoniae isolates were 9% (41/455). In AST, colistin, polymyxin B and tigecycline were the most effective antibiotics. The overall prevalence of multidrug-resistance (MDR) among both of the isolates was 58.0% (199/343). In the ESBL testing, 41.1% (n = 141) isolates were confirmed as ESBL-producers. The prevalence of ESBL-producing E. coli was 43% (130/302) whereas that of K. pneumoniae was 26.8% (11/41). Similarly, 12.5% (43/343) of the total isolates, 10.9% (33/302) of E. coli and 24.3% of (10/41) K. pneumoniae were resistant to carbapenem. Among 43 carbapenem resistant isolates, 30.2% (13/43) and 60.5% (26/43) were KPC and MBL-producers respectively. KPC-producers isolates of E. coli and K. pneumoniae were 33.3% (11/33) and 20% (2/10) respectively. Similarly, 63.6% (21/33) of the E. coli and 50% (5/10) of the K. pneumoniae were MBL-producers. In MIC assay, 2.2% (4/179) of E. coli and 10% (2/20) of K. pneumoniae isolates were confirmed as colistin resistant (MIC ≥ 4 µg/ml). Overall, the prevalence of colistin resistance was 3.1% (6/199) and acquisition of mcr-1 was 16.6% (3/18) among the E. coli isolates.

Conclusion

High prevalence of drug-resistance in our study is indicative of a deteriorating situation of AMR. Moreover, significant prevalence of resistant enzymes in our study reinforces their roles in the emergence of drug resistance. Resistance to last resort drug (colistin) and the isolation of mcr-1 indicate further urgency in infection management. Therefore, extensive surveillance, formulation and implementation of effective policies, augmentation of diagnostic facilities and incorporation of antibiotic stewardship programs can be some remedies to cope with this global crisis.

SUBMITTER: Karki D

PROVIDER: S-EPMC8256586 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Klebsiella pneumoniae is a nosocomial pathogen with high morbidity and mortality rates in hospitalized patients. The emergence of multidrug-resistant K. pneumoniae has become more challenging to treat, with the prevalence of colistin-resistance. Therefore, reliable methods for detecting colistin resistance are required. Many plants' essential oils have antimicrobial activity and have been used to combat multiple antibiotic resistances. This study aimed to investigate the characterization and prevalence of the colistin resistance gene mcr-1 in K. pneumoniae in Egypt, evaluate rapid polymyxin NP test, determine the transferability of mcr-1 gene, and study the synergistic activity of eugenol combined with colistin against K. pneumoniae isolates. Eighty-two K. pneumonia isolates were collected from different human samples, followed by antibiotic susceptibility testing, rapid polymyxin NP test, and detection of the mcr-1 gene and its transfer frequency. Determination of the MICs of colistin alone and in combination with eugenol was performed, then mcr-1 gene expression was determined in the presence of eugenol. Thirty-two isolates (39%) were colistin-resistant. Rapid polymyxin NP test failed to detect resistant isolates with MICs below 32 µg/mL. Detection of mcr-1 gene was made in 27 (84%) of colistin resistant isolates. The rest isolates possess alteration in the mgrB gene which probably causes colistin resistance. The mcr-1 gene was transferred by conjugation to other sensitive isolates. MIC of eugenol ranged from 416 to 1664 µg/mL, and FICI ranged from 0.265 to 0.75. Results also revealed suppression of mcr-1 gene expression in the presence of sub MIC of eugenol. Our results demonstrated a high prevalence of mcr-1 in Egypt and its ability to transfer to other strains. Difficult determination of colistin-resistant isolates with low values with rapid polymyxin NP test was apparent. Eugenol exerted a synergistic effect with colistin and improved its antimicrobial activity.