C-171. Evaluation of a Novel Swab Transport System for Maintaining Viability of Anaerobes and Impact of Using Different Inoculum Broths

S. E. Farhat1, G. Lim1, R. Malonzo1, B. Shingala1, A. E. Simor1,2,3;
1Alpha Lab., Inc., Toronto, ON, CANADA, 2Sunnybrook Hlth. Sci. Ctr., Toronto, ON, CANADA, 3Univ. of Toronto, Toronto, ON, CANADA.

Background: Swabs are often used in general practice and surgery for purposes of sampling, transporting, and maintaining viability of pathogens present. The objectives of this study were (1) to evaluate the performance of a novel multipurpose swab, the Amies Plus SP140X (Starplex Scientific Inc., Toronto, Canada) for its ability to maintain viability of anaerobes at 20-25°C (RT) and 4-6°C (FRG), and (2) to compare its performance when using different broths for inoculum preparation: phosphate buffer saline (PBS), Schaedler’s broth (SB), and Fastidious Anaerobe Broth (FAB). Methods: Using CLSI M40A Roll-Plate Method, swabs were seeded in duplicate with 10 anaerobes: 5 reference strains (Bacteroides fragilis [Bf] ATCC 25285, Clostridium novyi [Cn] ATCC 7659, Fusobacterium nucleatum [Fn] ATCC 25586, Peptostreptococcus anaerobius [Pa] ATCC 27337, Prevotella melaninogenica [Pm] ATCC 25845) and 5 clinical strains (Actinomyces sp. [Ac], B. ureolyticus [Bu], B. vulgatus [Bv], C. perfringens [Cp], C. sordellii [Cs]). Organisms were suspended in PBS, SB, and FAB and serially diluted to inoculum concentrations ranging from 104-105 CFU/ml. Swabs were stored at RT and a duplicate set at FRG, and plated on pre-reduced brucella agar at 0, 24, and 48 hr. Plates were incubated anaerobically for 48 hr. Viability was compared to the zero-hr count for each organism-broth combination at RT and FRG for each time interval. Results: Bf, Bu, Bv and Cp were adequately recovered from swabs regardless of time interval, storage temperature, or inoculum broth. Higher CFU counts were obtained by swabs seeded with FAB or SB suspensions than by those with PBS, and by swabs stored in FRG compared to those in RT. With PBS, there was no recovery in RT at 24 hr of Cn, Fn, Pa, or Pm, or at 48 hr of Ac or Cs, but they were viable up to 48 hr in FRG, except for Fn, which survived for 24 hr only in swabs seeded with FAB or SB suspensions and stored in FRG. Conclusions: SP140X is capable of maintaining viability of anaerobes for at least 24 hr when tested in FAB or SB and stored in FRG. PBS is suboptimal to FAB and SB for supporting anaerobe viability. Swab refrigeration enhances recovery of anaerobes.