Evaluation of the Copan eSwab®, a liquid-based microbiology transport system, for the preservation of Neisseria gonorrhoeae at different temperatures

Aims and objectives: To evaluate the survival duration of Neisseria gonorrhoeae from male urethral discharge specimens collected using the Copan eSwab (R) liquid-based microbiology transport system, at both ambient and refrigerator temperatures. Methods: Three urethral swabs (one Dacron, two Copan eSwabs (R)) were collected from each male patient presenting with purulent urethral discharge to a community-based primary healthcare centre in Johannesburg. The Dacron swab was directly inoculated onto New York city agar medium, and the Copan eSwabs (R) transported and held at room and refrigerator temperature, for daily sub-culture onto New York city agar over a total period of seven days (168 h). The utility of Copan eSwabs (R) for the transport and survival of N. gonorrhoeae at different temperatures was determined by comparison to culture obtained by 'gold standard' direct plate inoculation. Results: N. gonorrhoeae isolation rates from Copan eSwabs (R) at fridge temperature and ambient temperature were as follows: 87.9% vs 79.3% at 48 h; 67.2% vs 60.3% at 72 h; 60.3% vs 22.4% at 96 h; and, 53.4% vs 3.4% at 120 h, respectively. The viability of subculture decreased significantly from eSwabs (R) maintained at room temperature from 96 h onwards of specimen collection. Conclusion: To ensure the preservation and an acceptable isolation rate of N. gonorrhoeae from urethral discharge specimens, Copan eSwabs (R) should be transported and maintained at refrigerator temperatures, and must reach the processing laboratory by at least 120 h (5 days) after collection.