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Published on: May 28, 2014
A prospective surveillance study to determine the prevalence of 16S rRNA methyltransferase-producing Gram-negative
Emma Taylor1,2, Abhijit M Bal3, Indran Balakrishnan4
1National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Healthcare Associated Infections and Antimicrobial Resistance at Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
Objectives:
To determine the prevalence of 16S rRNA methyltransferase- (16S RMTase-) producing Gram-negative bacteria in patients in the UK and to identify potential risk factors for their acquisition.
Methods:
A 6 month prospective surveillance study was conducted from 1 May to 31 October 2016, wherein 14 hospital laboratories submitted Acinetobacter baumannii, Enterobacterales and Pseudomonas aeruginosa isolates that displayed high-level amikacin resistance according to their testing methods, e.g. no zone of inhibition with amikacin discs. Isolates were linked to patient travel history, medical care abroad, and previous antibiotic exposure using a surveillance questionnaire. In the reference laboratory, isolates confirmed to grow on Mueller-Hinton agar supplemented with 256 mg/L amikacin were screened by PCR for 16S RMTase genes armA, rmtA-rmtH and npmA, and carbapenemase genes (blaKPC, blaNDM, blaOXA-48-like and blaVIM). STs and total antibiotic resistance gene complement were determined via WGS. Prevalence was determined using denominators for each bacterial species provided by participating hospital laboratories.
Results:
Eighty-four isolates (44.7%), among 188 submitted isolates, exhibited high-level amikacin resistance (MIC >256 mg/L), and 79 (94.0%) of these harboured 16S RMTase genes. armA (54.4%, 43/79) was the most common, followed by rmtB (17.7%, 14/79), rmtF (13.9%, 11/79), rmtC (12.7%, 10/79) and armA + rmtF (1.3%, 1/79). The overall period prevalence of 16S RMTase-producing Gram-negative bacteria was 0.1% (79/71 063). Potential risk factors identified through multivariate statistical analysis included being male and polymyxin use.
Conclusions:
The UK prevalence of 16S RMTase-producing Gram-negative bacteria is low, but continued surveillance is needed to monitor their spread and inform intervention strategies.
Insights
The UK found a low prevalence of 16S rRNA methyltransferase- (16S RMTase-) producing Gram-negative bacteria. Continued surveillance is crucial for monitoring spread and informing interventions.
Area of Science:
- Microbiology
- Antimicrobial Resistance
- Public Health
Background:
- 16S rRNA methyltransferases (16S RMTases) confer high-level resistance to aminoglycosides, critical antibiotics.
- Gram-negative bacteria producing these enzymes pose a significant threat to effective treatment.
- Understanding the prevalence and risk factors is vital for infection control.
Purpose of the Study:
- To determine the prevalence of 16S RMTase-producing Gram-negative bacteria in UK patients.
- To identify potential risk factors associated with acquiring these resistant bacteria.
Main Methods:
- A 6-month prospective surveillance study involving 14 UK hospital laboratories.
- Analysis of *Acinetobacter baumannii*, Enterobacterales, and *Pseudomonas aeruginosa* isolates with high-level amikacin resistance.
- Screening for 16S RMTase and carbapenemase genes using PCR and whole-genome sequencing (WGS).
Main Results:
- Out of 188 submitted isolates, 84 showed high-level amikacin resistance, with 79 (94%) harbouring 16S RMTase genes.
- The most common 16S RMTase gene was *armA* (54.4%), followed by *rmtB*, *rmtF*, and *rmtC*.
- The overall prevalence was 0.1% (79/71,063), with male sex and polymyxin use identified as risk factors.
Conclusions:
- The prevalence of 16S RMTase-producing Gram-negative bacteria in the UK is currently low.
- Ongoing surveillance is essential to track the emergence and spread of these resistant organisms.
- Findings will inform targeted intervention strategies to combat antimicrobial resistance.
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