Evaluation of ESwab™ (COPAN) for the detection of Ureaplasma urealyticum and Mycoplasma hominis from genital specimens with Mycoplasma Duo kit (BIO-RAD)

OBJECTIVES

To validate ESwab™ as an alternative collection and transport medium for identification and titration of genital mycoplasma by using the Mycoplasma Duo kit.

1) Comparison between 3 different methods for Mycoplasma culture, identification and titration of 25 clinical specimens and various dilutions of U. parvum ATCC 27815 (Up) and M. hominis ATCC 27618 (Mh) strains :

  • Method 1 : collection by a Rayon swab, transfer into the suspension medium of the Mycoplasma Duo kit (Bio-Rad France) and microplate seeding according to manufacturer’s instructions
  • Method 2 : collection and transport by Eswab™ (COPAN) and transfer of 200 μl of ESwab™ medium into the suspension medium of the Mycoplasma Duo kit before microplate seeding
  • • Method 3 : collection by ESwab™ and direct seeding of the microplate by 100μl of Eswab™ medium
  • Transport < 48 hours at room temperature
  • Inoculation of an A7 agar (BioMérieux, France) as gold standard, in each case
  • Incubation, reading and interpretation according to manufacturer’s instructions

2) Statistical analysis of patient’s results during one year before and after introducing Eswab™ for mycoplasma diagnosis in our lab (comparing percentages)

RESULTS

ATCC strains

With ATCC strains, there was no difference between the method 1 and 2. The method 3 didn’t allow the detection of Mh at every concentration and Up at the lowest.

Clinical specimens

About the 25 clinical specimens :

  • 17 negative cultures with every method
  • 2 samples contaminated by yeast
  • 3 positive cultures with U. urealyticum (Uu) ≥ 104 colour changing unit/ml for the 3 methods
  • 1 culture positive with Uu ≤ 103 CCU for methods 1 and 2 and negative for method 3
  • 1 culture positive with Uu ≥ 104 CCU for the 3 methods and Mh ≥ 104 CCU for methods 1 and 3 and Mh ≤ 103 CCU with method 2
  • 1 culture positive with Uu ≥ 104 CCU for methods 1 and 3 and Uu ≤ 103 CCU with method 2

Results of the six positive clinical specimens

Statistical analysis of patient’s results during one year before and after introducting Eswab™ as collection medium

No statistically significant difference between the two study periods was found : 269 specimens (27%) positive in 2009 versus 320 (26%) in 2010 with about a thousand clinical specimens in each cohort.

Comparison of U. ureaplasma and M. hominis results between 2009 and 2010

CONCLUSION

  • Transfer of 200 μl ESwab™ into the Bio-Rad suspension medium provides equivalent results in comparison with the method recommended by Bio-Rad.
  • Use of ESwab™ for collection and transport of mycoplasma with Mycoplasma Duo kit simplifies the detection of genital mycoplasma by allowing multiple testing from the same original specimen.