An evaluation of pre-poured selective media for the isolation of Neisseria gonorrhoeae

Abstract

Fourteen commercial media supplied as pre-poured plates were compared with an 'inhouse' selective medium for their ability to support the growth of 105 gonococcal isolates (representing a wide variety of serovars encountered in natural infection), 25 meningococcal and 20 Neisseria lactamica isolates, and to inhibit the growth of 71 isolates of non-pathogenic neisseriae and miscellaneous organisms. Only two of the prepoured plate media and the in-house selective medium yielded growth of duplicate cultures of all 105 gonococcal isolates after incubation for 24 h: one other medium provided growth of all the isolates after incubation for 48 h. The ability of the various media to suppress the growth of the 71 isolates of non-pathogenic neisseriae and miscellaneous organisms ranged from 97.2 to 71.8% of isolates inhibited. Of the four media that enabled growth of all the gonococcal strains, inhibition was 94.4% for the inhouse medium, 85.9% and 80.3% for the two media on which all gonococci grew after 24 h and 71.8% for the medium on which all of the gonococci grew after 48 h. Failure of growth of gonococci was associated with: serogroup IA isolates (p < 0.001), AHU auxotype (p < 0.001) and the presence of vancomycin rather than lincomycin in the selective medium (p < 0.02).

Evaluation of Gen-Probe APTIMA-Based Neisseria gonorrhoeae and Chlamydia trachomatis Confirmatory Testing in a Metropolitan Setting of High Disease Prevalence

“…The sensitivities of culture assays for the fastidious pathogen Neisseria gonorrhoeae can be affected by the specimen collection device used (14), the viability of organisms in certain transport systems (27), and the various selective media used (33). Such factors contributed to the development of molecular diagnostic assays for these sexually transmitted agents.…”

Neisseria gonorrhoeae culture growth rates from asymptomatic individuals with a positive nucleic acid amplification test

“…Little effort has been made towards improving culture media for gonococci in extragenital locations, despite the increasing need to monitor MDR‐NG in pharyngeal infections (Young and Moyes 1996). Gonococcal isolation from extragenital locations is significantly lower than from genital locations as shown here (Table 3) and in many studies (Alexander 2009; Harryman et al .…”

“…2014). Therefore, modified Thayer‐Martin medium and many similar commonly used commercial media such as that used here, chocolate agar PolyViteX VCAT3 (bioMérieux, Marcy‐L'Étoile, France), contain, apart from nutritional factors (NAD and hemin), antimicrobial agents (vancomycin, nystatin, colistin, and trimethoprim) (Young and Moyes 1996). The appearance of vancomycin susceptible isolates, ranging from 2 to 14%, has been reported (Mirret et al .…”

“…It is likely that the main problem is growth inhibition of commensal microbiota, highly resembling gonococci, especially in the pharynx (Papp et al 2014). Therefore, modified Thayer-Martin medium and many similar commonly used commercial media such as that used here, chocolate agar PolyViteX VCAT3 (bioM erieux, Marcy-L' Etoile, France), contain, apart from nutritional factors (NAD and hemin), antimicrobial agents (vancomycin, nystatin, colistin, and trimethoprim) (Young and Moyes 1996). The appearance of vancomycin susceptible isolates, ranging from 2 to 14%, has been reported (Mirret et al 1981), which could cause a diminished recovery rate; however, data about vancomycin susceptibility in our environment are unknown (Salmer on et al 2020).…”

Comparison of Direct Inoculation and Copan Transport Systems for Isolation of Neisseria gonorrhoeae from Endocervical Specimens

“…As opposed to mere loss of viability of N. gonorrhoeae in the Copan transport system during the holding period, other factors were likely to be of equal or greater significance. Overgrowth of competing organisms, including commensal bacteria and yeasts, has been implicated in other circumstances (5,9,13,18). The 24-h holding period before plating provided an opportunity for commensal yeast to multiply at room temperature, overwhelming the nystatin in the MTM medium.…”