Susceptibility in vitro of clinically metronidazole-resistant Trichomonas vaginalis to nitazoxanide, toyocamycin, and 2-fluoro-2'-deoxyadenosine.
This study investigates the susceptibility of a clinically metronidazole (Mz)-resistant isolate of Trichomonas vaginalis to alternative anti-trichomonal compounds. The microaerobic minimal inhibitory concentration (MIC) of the 5-nitroimidazole (NI) drug, Mz, against a typical Mz-susceptible isolate of T. vaginalis is around 3.2 microM Mz while the clinically, highly Mz-resistant isolate has an MIC of 50-100 microM. This isolate was cross-resistant to other members of the 5-NI family of compounds including tinidazole and other experimental compounds and maintained resistance under anaerobic conditions. In addition, this isolate was cross-resistant to the 5-nitrothiazole compound nitazoxanide and the 5-nitrofuran derivative, furazolidone. Adenosine analogues toyocamycin and 2-fluoro-2'-deoxyadenosine with no nitro group were also less effective against the clinically Mz-resistant isolate than a Mz-susceptible one. Three other isolates which were determined to be Mz-resistant soon after isolation lost resistance in the long term. One other isolate has maintained some level of permanent Mz resistance (MIC of 25 microM). A multi-drug resistance mechanism may be involved in these clinically Mz-resistant isolates.
Infectious Diseases and Division, Queensland Institute of Medical Research, Brisbane, 4006, Queensland, Australia.
Janelle M
JM
Wright
Linda A
LA
Dunn
Zygmunt
Z
Kazimierczuk
Anita G
AG
Burgess
Kenia G
KG
Krauer
Peter
P
Upcroft
Jacqueline A
JA
Upcroft
D000693:Anaerobiosis; D000994:Antitrichomonal Agents / Q000494:pharmacology*; D003839:Deoxyadenosines / Q000494:pharmacology*; D004351:Drug Resistance; D005260:Female; D006801:Humans; D008795:Metronidazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009574:Nitro Compounds; D013844:Thiazoles / Q000494:pharmacology*; D014127:Toyocamycin / Q000494:pharmacology*; D014247:Trichomonas Vaginitis / Q000469:parasitology; D014246:Trichomonas vaginalis / Q000187:drug effects* / Q000302:isolation & purification
D000994:Antitrichomonal Agents; D003839:Deoxyadenosines; D009574:Nitro Compounds; D013844:Thiazoles; D008795:Metronidazole; C030964:2'-fluoro-2'-deoxyadenosine; D014127:Toyocamycin; C041747:nitazoxanide