Comparison of endocervical swabs to cultured isolates for the detection of antimicrobial resistance determinants in Neisseria gonorrhoeae
Keywords:
Neisseria gonorrhoeae, penicillin, ciprofloxacin, tetracycline, spectinomycin, azithromycin, cefixime, ceftriaxone,, antimicrobial resistance, pregnant womenAbstract
Background: The global emergence of antimicrobial resistance (AMR) in Neisseria gonorrhoeae to various antibiotics is a public health concern. To date, there have been no published South African studies that have compared the primary swab to the cultured isolates for the detection of N. gonorrhoeae AMR determinants. This study provides data on such a comparison.
Methods: Paired endocervical swabs were collected from 307 pregnant women. The first swab was stored in an Amies charcoal transport media for culture assessment and the second swab was used for the molecular detection of resistant determinants. Specific targets (genes/plasmids/mutations) associated with resistance to penicillin, tetracycline, ciprofloxacin, spectinomycin, cefixime, azithromycin and ceftriaxone were detected from both the cultured isolates and the endocervical swabs.
Results: Of the 307 samples tested in this study, only six samples tested positive for culture. A total of 24 samples tested positive for N. gonorrhoeae with the quantitative polymerase chain reaction (qPCR) assay. The six samples which tested positive for culture fell within the qPCR positives group. Since this study was designed to directly compare the culture swabs to the endocervical swabs for the detection of AMR determinants, the current analysis included only the six culture samples and six paired endocervical swab samples (n = 6). All six isolates were resistant to tetracycline and penicillin G while five of the six isolates were resistant to ciprofloxacin. All isolates were susceptible to the remaining antimicrobials. There was a 100% correlation between the cultured isolates and endocervical swabs for detecting the specific AMR determinants, conferring resistance to tetracycline, penicillin G and ciprofloxacin.
Conclusion: Based on the findings of this study, tracking emerging patterns of resistance from the molecular level using only the endocervical swabs may serve as an attractive future research direction.
