Quest for ideal transport conditions and factors affecting revival of Neisseria gonorrhoeae isolates: Experience of a National Reference Laboratory

Abstract

Background: Neisseria gonorrhoeae (Gonococcus-GC) is a fastidious, autolytic Gram-negative diplococcus with stringent growth requirements, and cannot be cultivated in a routine microbiology laboratory, without well-equipped incubators, reagents and special media. Hence, many clinics and laboratories prefer to ship the specimens or isolates to a dedicated referral laboratory for confirmation of isolates and the antimicrobial susceptibility testing. Thus, transportation conditions for gonococcal isolates, become crucial for its recovery and successful isolation in the laboratory. This retrospective study was conducted at a national referral laboratory for gonococcus, in India, over a period of three years. Aim: In this study, an attempt was made to determine the factors affecting revival of isolates of gonococci, that were despatched, from across India, to the referral laboratory for confirmation of species and antimicrobial susceptibility patterns. Method: Over a three-year period, the culture plates, test tubes or vials used for transporting gonococcal isolates, and their modes of transport to referral laboratory, were studied in detail. The isolates were revived (whenever possible), sub cultured and identified by standard methods in the referral laboratory. Results: A total of 77 samples were processed for revival and 83.12 % of isolates were recovered, with failure of recovery in 16.88 % of specimens. Conclusion: Several factors play a role in the successful revival of Neisseria gonorrhoeae from culture isolates transported across the Indian subcontinent. These include- purity of growth, culture media used for transport, sending of isolates in duplicates, temperature, time, distance and season of transport. All these factors must be kept in mind when transporting gonococcal isolates, for successful revival. Finally, the skills of the laboratory technician are of immense importance too.