Symbiosis of Mycoplasma hominis in Trichomonas vaginalis may link metronidazole resistance in vitro

J. C. Xiao, L. F. Xie, S. L. Fang, M. Y. Gao, Y. Zhu, L. Y. Song, H. M. Zhong, Z. R. Lun

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Fourteen of 28 Trichomonas vaginalis isolates collected from patients in Guangzhou, China from 2003 to 2004 were found to be naturally infected with Mycoplasma hominis, as determined by PCR using specific primers. In vitro metronidazole sensitivity assay of the 28 isolates revealed four displaying low susceptibility [minimum lethal concentration (MLC)=∼ 13-25 μg/ml] and another four displaying high resistance (MLC=50-100 μg/ml). The overwhelming majority of these resistant isolates (7/8) were mycoplasma-infected. The mean of MLCs of mycoplasma-infected isolates is ∼10-fold higher than the mean of noninfected isolates (p=0.029). Sequence analyses of PCR-amplified small subunit-large subunit rRNA interspacer regions (ITS1/5.8S/ITS2) revealed that 23 of the 28 samples are identical, the remaining five being separable into two groups, each with a single point mutation. These internal transcribed spacer sequence variants are associated neither with mycoplasma infection nor with drug resistance. In contrast, random amplified polymorphic DNA analyses of DNAs using 10 different primers showed that the drug-resistant isolates are clustered together in association with mycoplasma infection, albeit more loosely. Taken together, the results obtained from this study suggest that in vitro metronidazole resistance of T. vaginalis is related to mycoplasma infection of this protozoan.

Original languageEnglish (US)
Pages (from-to)123-130
Number of pages8
JournalParasitology Research
Issue number1
StatePublished - Dec 2006
Externally publishedYes

ASJC Scopus subject areas

  • Parasitology
  • General Veterinary
  • Insect Science
  • Infectious Diseases


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