C-172. Recovery of Haemophilus influenzae (HI) Using the New ESwab™ Transport System

S. Silbert, A. S. Pereira, L. Paschoal, J. Monteiro, A. C. C. Pignatari;
Federal Univ. of Sao Paulo, Sao Paulo, BRAZIL.

Background: A new patented Flocked Swab with Liquid Amies, Copan, CA, USA (ESwab™) was designed to improve the sensitivity of the traditional transport swab systems. In this new swab the organism inoculum theoretically is released into 1ml of Amies Liquid and after that it should be possible to perform different tests on the collected sample. The purpose of this study was to evaluate the ability of ESwab to support viability of HI and produce identical growth recoveries when multiple plate culture repetition protocols are conducted. A Quadrant One (P.1) seed and Kirby-Bauer (P.2) protocols were used. Methods: A 0.5 McFarland suspension of HI ATCC 10211 strain was performed in 0.85% physiological saline from a 24h growth organism. For P.1 a 1/50,000 dilution of the bacteria was used and for P.2 the dilution was 1/10,000. Regular Transystem swabs, as well as ESwabs (Copan, USA) were inoculated with 100μl of the strain suspension. Swabs were held at 4°C for 0h, 24h, 48h and 1 week. On P.1, just one quadrant of a Chocolate Agar Plate (CAP) was seed, using first a regular Transystem swab and second, an ESwab. A third action was done by dropping 100μl from the ESwab medium in the first quadrant of a CAP and spread it, after liquid evaporating. These three steps were repeated 10 times, using the same swab and 10 different plates for each swab time holding point. On P.2, the same steps were performed, but instead of a one quadrant, a whole CAP was seeded. Bacterial survival was evaluated after 48h incubation at 35°C. Results: HI strain was recovered from all ESwabs, at all holding time points and inoculation methods. No significant difference was observed on bacterial recovery rates when comparing the two different ESwab plate inoculation methods. None of the Transystem swabs using P.1 and P.2 maintained viability for HI after 1 week at 4°C and for time points 0h, 24h and 48h the number of colonies recovered from ESwabs was superior. Conclusion: The new ESwab proved to be an excellent system to recover HI viability. It provides a homogeneous sample suspension enabling multiple replicate plate inoculations with a high degree of reproducibility and consistency of organism transfer.