Metronidazole still first choice for Trichomonas Vaginalis: Teesside experience 1995-2000.

Tayal SC; Opaneye AA Department of Genitourinary Medicine, Middlesbrough General Hospital

Key words: Trichomonas vaginalis; co-infections; metronidazole

Introduction
Trichomonas vaginalis (TV) [figure 1] is a globally common sexually transmitted parasite. About 120 million women suffer from trichomoniasis every year. In developed countries, however, the numbers have declined dramatically from a peak in the late 1950s. In 1999, 6406 cases were reported from Genito-Urinary Medicine clinics1. Without adequate investigations trichomoniasis may be confused with bacterial vaginosis, which is a relatively common cause of vaginal discharge occurring in up to 30 percent of women. Trichomonas vaginalis usually presents with a frothy yellow vaginal discharge and vulval itching. In severe cases there may be vulvo-vaginal excoriations due to the patient scratching.

Methods
The case notes of all the women diagnosed with TV during the period of 1995-2000 at the GUM department at Middlesbrough General Hospital were carefully examined. Information for concurrent infections, persistent TV and partner treatment was retrieved.

Results
These are shown in table 1 and figure 2. During the period of study, 3751 women (new and re-registered) attended the department, out of these 50 i.e. 1.3% were diagnosed to have TV. The age of these patients ranged between 14-50 years, with a mean of 30.9 years. Two of the women were pregnant and were treated in the second trimester. One woman worked as a prostitute; while one patient was diagnosed from a cervical cytology report. All patients were initially offered the standard treatment of metronidazole 400 mg twice a day for seven days. However, six (12%) had persistent TV infection. One responded to Tinidazole, and one needed the addition of amoxycillin thrice a day for seven days. This 39 year old woman had previously failed to respond to 2 courses of metronidazole – 2 Gm stat; and 400 mg twice a day for one week. A previous high vaginal swab was positive for Group B streptococcus. The other four responded to a second course of metronidazole.

The male contacts of the four patients with persistent infection were given epidemiological treatment. Many of these patients (48%) had concurrent sexually transmitted infections, see table 1.

Discussion
The florid manifestations of acute pelvic inflammatory disease or the most insidious complications such as infertility and ectopic pregnancy are important reasons for controlling Chlamydia trachomatis and Neisseriae gonorrhoea. Trichomonas vaginalis is not thought to be a major cause of any of these sequelae and, as a result, many consider the disease more of a nuisance than a public health problem. This study has confirmed that TV is frequently associated with other pathogens. The prevalence of gonorrhoea and chlamydia in this cohort of women with is 22 %. These women left untreated ran the risk of developing pelvic inflammatory disease and subsequent tubal infertility. Metronidazole (400mg twice daily for 5-7 days or 2Gm single dose ) is still the first choice of treatment for most cases of trichomoniasis 2,3. The failure of women with vaginal trichomoniasis to respond to metronidazole is not uncommon. In most cases this probably results from a failure to take medication as advised or reinfection from an untreated, usually asymptomatic, male sexual partner. Whenever there is a suspicion of persistence, the possibility of metronidazole inactivation by vaginal aerobic and anaerobic bacteria should be covered by prescribing a combination of either amoxycillin or erythromycin with a high dose metronidazole4. In our study only one patient had to be given amoxycillin as she had associated infection with group B streptococcus. Partner treatment can be effective in decreasing long term re-infection rates. Forty eight percent of male contacts of the index patients were treated. Developing a more effective partner treatment strategies will help to reduce the prevalence of this condition. 

References
1. Trends in sexually transmitted infections in United Kingdom 1990-1999. New episodes seen at genitourinary medicine clinics.
London: Department of Health, 2000. 
2. Forna F, Imezoglu AM. Interventions for treating trichomoniasis in women
( Cochrane review ). In: The Cochrane Library, 2,2001. Oxford
3. Schmid G. Single- Dose Metronidazole still first choice for most cases of 
Trichomoniasis. J Reprod Med 2001; 46:545-549
4.Pattman RS. Recalcitrant vaginal trichomoniasis. Sex Transm Inf 1999;75:127-128

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