Background: Accurate detection of Neisseria gonorrhoeae antimicrobial resistance is essential for appropriate\nmanagement and prevention of spread of infection in the community. In this study Calibrated Dichotomous\nSensitivity (CDS) and Clinical Laboratory Standards Institute (CLSI) disc diffusion methods were compared with\nminimum inhibitory concentration (MIC) by Etest in Neisseria gonorrhoeae isolates from Karachi, Pakistan. CDS and\nCLSI disc diffusion techniques, and Etest for ceftriaxone, penicillin G, spectinomycin and ciprofloxacin against 100\nisolates from years 2012ââ?¬â??2014 were performed. Due to lack of CLSI breakpoints for azithromycin, it was interpreted\nusing cut-offs from British Society of Antimicrobial Chemotherapy (BSAC). Due to lack of low concentration\ntetracycline discs, tetracycline was tested with CLSI disc diffusion and Etest only. Comparisons were based on the\nidentified susceptibility, intermediate susceptibility and resistance (SIR) categories using the different methods.\nComplete percent agreement was percentage agreement achieved when test and reference method had identical\nSIR-category. Essential percent agreement was percentage agreement when minor discrepancies were disregarded.\nResults: There was 100 % and 99 % overall essential agreement and 50 % versus 23 % overall complete agreement\nby CDS and CLSI methods, respectively, with MICs for all tested antibiotics. Using either method, there was 100 %\ncomplete agreement for ceftriaxone and spectinomycin. There was 90 % versus 86 % complete agreement for\nciprofloxacin, and 60 % and 75 % for penicillin using CDS and CLSI method, respectively. Essential agreement of\n99 % and complete agreement of 62 % was found for tetracycline with CLSI method. There was 100 % essential\nand complete agreement by CDS, BSAC and Etest for azithromycin.\nConclusion: No major errors with regard to identified SIR-categories were found for penicillin, ciprofloxacin,\nceftriaxone and spectinomycin using CLSI and CDS methods. All isolates were susceptible to ceftriaxone and\nspectinomycin, and 99 % to azithromycin. In low-resource settings, both the CLSI and CDS disc diffusion techniques\nmight be used for susceptibility testing of gonococcal isolates. However, these methods require considerable\nstandardization and quality controls for adequate levels of reproducibility and correct interpretation to reflect\nappropriately the MIC values of the different antimicrobials. New, emerging, or rare resistance should be confirmed\nby MIC determination.
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