Wild-Type Gyrase A Genotype of Neisseria gonorrhoeae Predicts In Vitro Susceptibility to Ciprofloxacin: A Systematic Review of the Literature and Meta-Analysis

Abstract

Multidrug-resistant Neisseria gonorrhoeae infections have been declared one of the top three urgent threats to public health. Approaches to combat resistance include targeted therapy with antibiotics previously thought to be ineffective, made possible by rapid molecular assays to predict susceptibility. Previous studies have associated the gyrase A (gyrA) gene of Neisseria gonorrhoeae with in vitro resistance to ciprofloxacin. We conducted a systematic review of studies comparing Neisseria gonorrhoeae gyrA genotype results with conventional antimicrobial susceptibility test results. We identified 31 studies meeting inclusion criteria, among which seven different loci for mutations in the gyrA gene were identified, from sixteen countries between the years of 1996 and 2016. We then performed a meta-analysis among those studies stratifying by use of real-time PCR or non-real-time PCR technique, and compared the summary receiver operating characteristic curves (sROC) between the two PCR methods. Among studies using real-time PCR the pooled estimate of sensitivity and specificity of gyrA genotype results for the prediction of Neisseria gonorrhoeae susceptibility to ciprofloxacin were 98.2% (95% CI 96.5%-99.1%) and 98.6% (95% CI 97.0%-99.3%), respectively. The sROCs for studies using real-time PCR techniques were well separated from those using non-real-time PCR techniques, with only slight overlap in the confidence intervals, suggesting that real-time PCR techniques were a more accurate approach. GyrA genotype testing is a novel approach to combating the emergence of multi drug-resistant Neisseria gonorrhoeae, and is a sensitive and specific method to predict in vitro ciprofloxacin susceptibility.

Multiplex Real-Time PCR Assay for Simultaneous Identification of Neisseria gonorrhoeae and Its Ciprofloxacin Susceptibility Status

“…In our study, we considered gyrA mutations alone and clearly identified the ciprofloxacin-susceptible and resistant isolates in a single multiplex RT-PCR assay. Thus, our results support the findings by others and demonstrate that the gyrA region alone is sufficient for the determination of ciprofloxacin susceptibility status (13,18,22,26). We determined through DNA sequencing that the majority of isolates with intermediate susceptibility in our study carried mutations only at the S91 or D95 position, and not both ( Table 3); one isolate with intermediate susceptibility in panel 2 had mutations at both S91 and D95 positions.…”

“…One study demonstrated detection of N. gonorrhoeae and its ciprofloxacin susceptibility status, but this assay required three consecutive tests for a clear interpretation (27). Several recent publications introduced RT-PCR-based methods for detection of mutations at the gryA S91 locus from clinical specimens (18,26,28). However, these analyses were restricted only to the S91 locus and the assays could be more likely to have errors if ciprofloxacin resistance arose through mutations in the D95 locus.…”

Epidemiology of Neisseria gonorrhoeae Gyrase A Genotype, Los Angeles, California, USA

“…We characterized the epidemiology of fluoroquinolone resistance at UCLA Health (Los Angeles, CA, USA) by using a rapid molecular gyr A gene assay that predicts ciprofloxacin susceptibility ( 3 , 6 ). UCLA Health is a large healthcare system in Los Angeles County compound of 2 hospitals, 2 emergency departments, and >150 primary care clinics serving ≈500,000 patient-visits each year.…”

“…To combat this growing threat, we developed and implemented a real-time reverse transcription PCR at the University of California, Los Angeles (Los Angeles, CA, USA), to detect the codon 91 mutation in the gyrase A ( gyr A) gene in N. gonorrhoeae remnant clinical specimens ( 2 ). Mutations in the gyr A gene of N. gonorrhoeae , specifically at codon 91, have been demonstrated to reliably predict resistance to ciprofloxacin ( 3 ).…”

Improved determination of Neisseria gonorrhoeae gyrase A genotype results in clinical specimens

“…2 The absence of mutation at codon 91 of the gyrase A gene (gyrA) of N. gonorrhoeae has been shown to have both a high sensitivity and specificity (.98%) for predicting N. gonorrhoeae susceptibility to ciprofloxacin. 3 In November 2015, we implemented a laboratory-developed molecular assay for determining the gyrA genotype of all N. gonorrhoeae infections at the University of California, Los Angeles. 4 Our findings showed an increase in the use of ciprofloxacin for the treatment of N. gonorrhoeae infections in clinical practice; however, one limitation of that implementation was the high frequency of indeterminate genotype results, especially among pharyngeal specimens.…”