Neonatal Trichomonas vaginalis infection: a case report and review of literature

A 29-1/7-week premature female neonate, weighing 1210 g, was born to a 19-year-old mother, after a pregnancy complicated by preterm labour and preterm premature rupture of membranes for 17 days. The symptomatic mother was diagnosed with Trichomonas vaginalis 16 days prior to delivery and had been treated with a single dose of 2 g metronidazole, orally. No information regarding infection and/or treatment of her sexual partner was known at the time of presentation. Due to suspicion of chorioamnionitis on the day of delivery, labour was augmented and the infant was delivered vaginally. On the first day of life (DOL), the neonate was intubated because of respiratory distress and given one dose of calfactant (3 mL/kg), but subsequently extubated on the same day and quickly weaned to room air by DOL 6. Given the history of maternal chorioamnionitis, the neonate was treated presumptively for sepsis with ampicillin and gentamicin. On DOL 5, during a routine urinalysis, T. vaginalis was found from a diaper specimen. The same day, a subsequent urine specimen was obtained using a sterile urine collection bag applied to the vulva, after thorough cleansing of perineum and external genitalia with sterile saline. The presence of T. vaginalis in this specimen was confirmed by microscopic evaluation. The presence of organisms with classic trichomonad morphology was considered diagnostic at this point, and no further diagnostic tests were performed. Numerous white blood cells were also present. Although the infant was initially asymptomatic, she was treated with two doses of metronidazole (15 mg/kg, then 7.5 mg/kg). Respiratory secretions were not examined at that time as the infant was asymptomatic. The infant continued to be clinically well and metronidazole was discontinued after a urinalysis from a suprapubic bladder tap was negative for trichomonad organisms. On DOL 14, the infant presented with recurrent apnoeic events. Blood, urine (suprapubic) and cerebrospinal fluid (CSF) cultures were drawn and the infant was started on vancomycin, cefotaxime for treatment of presumed sepsis. Given the history of T. vaginalis in the past, metronidazole was started in addition to the other antimicrobials. Blood cultures grew Staphylococcus epidermidis and the urine culture grew Escherichia coli and Enterococcus faecalis. The CSF culture was negative. Although the urinalysis was negative for T. vaginalis at this time, metronidazole treatment was continued for a total of five days. Vancomycin and cefotaxime was administered for eight days. The respiratory and other clinical symptoms indicative of infection resolved and the remainder of the hospitalization was uncomplicated. The infant was discharged in good condition to home at 46 days of age.

DISCUSSION

T. vaginalis is a single-cell, flagellate protozoan and a common cause of vaginitis in adult, sexually active women. Although two other species of Trichomonas (Trichomonas tenax and Trichomonas hominis) occur in humans, T. vaginalis is considered the only pathogenic trichomonad. ¹ Infection with trichmonads commonly affects adults, and infection with T. vaginalis is often encountered in pregnant women. Despite the recognition of pyuria in the urinalysis samples from neonates, T. vaginalis is not a commonly considered pathogen by neonatologists. However, cases of neonatal infection with T. vaginalis have been described. ^2–4 The mode of transmission in neonates has never been firmly established, but direct contact with the organism through vertical transmission from the maternal genitourinary tract seems most plausible. ² In previous decades, infection due to T. vaginalis has been described in neonates with vaginal discharge, and the organism has been detected in urine samples from neonates, as well as from tracheal aspirates. ^5–8

Maternal infection with T. vaginalis has frequently been associated with adverse outcomes of pregnancy, including prematurity, low birth weight and neonatal death. ^9,10 The prevalence of T. vaginalis in the USA is higher among African-Americans than Hispanics or Caucasians. ^10–12 Treatment recommendations for infants infected or colonized with T. vaginalis remain unclear to date. Although metronidazole does not appear to be teratogenic, in at least two independent studies the investigators suggested that lysis of trichomonads due to metronidazole treatment could elicit an inflammatory response triggering preterm labour. ^9,10 One study demonstrated that metronidazole therapy was effective in eradicating the organisms without producing serious side-effects. ¹³ The treatment with metronidazole in our case was discontinued after two days based on the infant's improved clinical condition and a subsequent urine specimen found to be negative for trichomonads. However, on DOL 14, the infant presented with clinical symptoms of sepsis, and given the prior history of T. vaginalis infection, the infant was restarted on metronidazole in addition to broad-spectrum antibiotics. In the literature, only a few case reports showed that treatment for seven days was effective in eradicating the organism. ⁵ Considering the evidence in the literature, an additional five-day course of metronidazole, to complete a total of seven days of treatment, was subsequently given to the patient presented in our case report. Another recent report described a neonate with respiratory symptoms who was colonized with T. vaginalis, who showed clinical improvement with metronidazole treatment. ¹⁴ However, the associated literature review in this report cited several cases of neonatal respiratory colonization and/or infection demonstrating improvement in respiratory status with only supportive care. ¹⁴ These studies together with this case report illustrate the need for a better understanding of trichomonad infections in neonates and infants, as well as the need for consensus guidelines for treatment.

A weak point in our case was the utilization of only microscopic examination of the subsequent urine specimens on DOL 7 and DOL 14. Considering the prior two-day treatment and the overall lower diagnostic sensitivity of microscopy for a single specimen, the addition of in-pouch culture or molecular test methods such as polymerase chain reaction could have been helpful in determining the proof of cure for the patient. Whether the subsequent development of urinary tract infections (UTIs) and sepsis in our patient was related to the possibility of continued, yet undetected presence of trichomonads remains uncertain.

While T. vaginalis infection in neonates may be uncommon in the general population, it should be considered in a high-risk patient population. T. vaginalis may play a role in multiple sites of neonatal infection including the respiratory and urinary tracts, and colonization of the urinary tract may increase the risk of developing concomitant bacterial UTIs. ⁸ With regard to our patient, we feel justified that the presence of pyuria on the initial urinalysis can be ascribed to the presence of T. vaginalis, which may have contributed to the subsequent development of bacterial infection. While the source and mode of transmission in our patient ultimately remain obscure, we believe that the mother's infection two weeks prior to delivery together with uncertain clearance of the organism were the source for the infant's infection.

Considering that in non-pregnant women it is not uncommon to miss the presence of T. vaginalis on a single microscopic examination, and further considering that pregnant women without symptoms of vaginal infection are not normally examined for T. vaginalis, we believe that in a high-risk neonatal/infant patient population with vaginal discharge or unexplained respiratory disease, nasal secretions, tracheal secretions, urine and vaginal swabs should be closely examined for trichomonads. Therefore, neonatologists, infectious disease consultants and hospital laboratories should be aware of the possibility of T. vaginalis infections in neonates born to high-risk mothers. Treatment with metronidazole should be considered in these cases to also avoid concomitant bacterial infections.