Evaluation of 4 swab transport systems for the recovery of ATCC and clinical strains with characterized resistance mechanisms.

Despite limitations of swab transport systems (STS), many clinical samples and bacterial isolates are sent on these devices. We evaluated the performance of 4 commercial STS: M40 Transystem (S1, Copan Italia, Bovezzo, Italy), UNI-TER (S2, MEUS, Piove di Sacco, Italy), Euromed (S3, LAB SERVICE, Surbo, Italy), and Eurotubo (S4, Deltalab, Rubí, Spain). Survival of ATCC and clinical strains with characterized resistance mechanisms, stored at room temperature and using the roll-plate method (NCCLS M40-A) after holding times of 0, 6, 24, 48, and 72 h, and 7 days, was assessed. After 24 h, only S1 was able to maintain Streptococcus pneumoniae (ATCC 6305), Haemophilus influenzae (10211), and Neisseria meningitidis (13090) viability with a percentage range of recovery with respect to the baseline count at zero time of 104-184%. Neisseria gonorrhoeae (43069) was uncultivable after 6 h with all STS except S1 (46% recovery). Eighteen percent recovery after 24 h and 7% after 6 h was observed for Fusobacterium nucleatum (25586) and Peptostreptococcus anaerobius (27337), respectively, but only with S1. Resistance mechanisms in clinical isolates do not affect survival with any of the STS.