Antibiotic susceptibility pattern of Neisseria gonorrhoeae strains isolated from five cities in India during 2013-2016

PURPOSE

Emergence of multidrug resistance in Neisseria gonorrhoeae, an STI of public health significance is the biggest challenge to gonorrhoea control. Monitoring for antimicrobial resistance is essential for the early detection of emergent drug resistance patterns.

METHODOLOGY

One hundred and twenty four N. gonorrhoeae strains were isolated between September 2013-August 2016 [82-New Delhi, 3-Pune, 3-Mumbai, 20-Secunderabad and 16-Hyderabad] to determine antimicrobial susceptibility and to compare the CLSI disc diffusion method with Etest for these strains. The results of the two methods were compared by using kappa statistics.

RESULTS

Ninety eight percent [CI: 96.2-100] of isolates were resistant to ciprofloxacin, 52 % [CI: 43.2-60.8] to penicillin, 56 % [CI: 47.2-64.7] to tetracycline and 5 % [CI: 1.2-8.8] to azithromycin. All the strains were susceptible to spectinomycin, ceftriaxone and cefixime except for two strains which showed decreased susceptibility to ceftriaxone and cefixime. Kappa scores for penicillin, azithromycin, ciprofloxacin, ceftriaxone and cefixime showed that the CLSI method had high agreement with Etest while tetracycline had substantial agreement.

CONCLUSION

Our data suggest that the disc diffusion method which is both cost effective and more feasible, can effectively be used routinely for monitoring antibiotic susceptibility in N. gonorrhoeae, in limited resource countries like India. We demonstrate the emergence of decreased susceptibility to ceftriaxone and cefixime and threshold levels of resistance to azithromycin in India. This underscores the importance of maintaining continued surveillance for antibiotic resistance in N. gonorrhoeae and a potential requirement for strategic change in guidelines in the not so distant future.

Evaluation of a cost effective in-house method for HIV-1 drug resistance genotyping using plasma samples

Objectives

Validation of a cost effective in-house method for HIV-1 drug resistance genotyping using plasma samples.

Design

The validation includes the establishment of analytical performance characteristics such as accuracy, reproducibility, precision and sensitivity.

Methods

The accuracy was assessed by comparing 26 paired Virological Quality Assessment (VQA) proficiency testing panel sequences generated by in-house and ViroSeq Genotyping System 2.0 (Celera Diagnostics, US) as a gold standard. The reproducibility and precision were carried out on five samples with five replicates representing multiple HIV-1 subtypes (A, B, C) and resistance patterns. The amplification sensitivity was evaluated on HIV-1 positive plasma samples (n = 88) with known viral loads ranges from 1000–1.8 million RNA copies/ml.

Results

Comparison of the nucleotide sequences generated by ViroSeq and in-house method showed 99.41±0.46 and 99.68±0.35% mean nucleotide and amino acid identity respectively. Out of 135 Stanford HIVdb listed HIV-1 drug resistance mutations, partial discordance was observed at 15 positions and complete discordance was absent. The reproducibility and precision study showed high nucleotide sequence identities i.e. 99.88±0.10 and 99.82±0.20 respectively. The in-house method showed 100% analytical sensitivity on the samples with HIV-1 viral load >1000 RNA copies/ml. The cost of running the in-house method is only 50% of that for ViroSeq method (112$ vs 300$), thus making it cost effective.

Conclusions

The validated cost effective in-house method may be used to collect surveillance data on the emergence and transmission of HIV-1 drug resistance in resource limited countries. Moreover, the wide applications of a cost effective and validated in-house method for HIV-1 drug resistance testing will facilitate the decision making for the appropriate management of HIV infected patients.