Infection with molluscum contagiosum virus, a poxvirus, normally has a typical clinical presentation; therefore, laboratory confirmation is infrequently sought and the virus is rarely isolated in culture. As reported herein, viral culture of specimens from atypical lesions may produce an abortive infection in limited cell lines and a cytopathic effect suggestive of herpes simplex virus.
CASE REPORTAn 18-year-old woman presented to her health care provider with a 1-month history of a rash in the pubic area. The lesions were not painful and the patient had no history of similar dermatological problems. She stated that her husband had a similar lesion on his upper inner thigh. No unusual travel, exposure, or social history was reported. Upon examination, the patient had a single, nontender lesion in the mons area that had a vesicular herpetic appearance and multiple lesions in the groin area resembling folliculitis.The provider suspected herpes simplex virus (HSV) infection and submitted a swab specimen collected from the lesion and placed in viral transport medium (Microtest M4-RT; Remel, Lenexa, KS) to the medical center virology laboratory for culture. A 750-l aliquot of the specimen was removed from the viral transport medium and placed in a separate tube. An antimicrobic suspension of penicillin (1,000 U/ml), streptomycin (1,000 g/ml), and amphotericin B (Fungizone [2.5 g/ml]; Sigma-Aldrich, St. Louis, MO) was prepared. Two hundred microliters of the antimicrobic solution was added to the 750-l aliquot of specimen, and the mixture was centrifuged for 10 min at 2,300 rpm (900 ϫ g). Two-hundred-microliter aliquots of the processed specimen were inoculated into MRC-5 (Diagnostic Hybrids, Inc., Athens, OH) and A549 (Diagnostic Hybrids, Inc., Athens, OH) tube cultures and incubated at 36°C. Discrete foci of ballooning or rounding fibroblasts suggestive of HSV were observed at 24 h in the MRC-5 cells (Fig. 1); however, no cytopathic effect (CPE) was observed in the A549 cells. Attempts to pass the observed CPE to a subsequent tube of MRC-5 cells from the primary culture were unsuccessful, which might indicate specimen toxicity; however, no such effects were observed in A549 cells. The abortive CPE, which resembled the CPE of HSV, resulted in the death of the MRC-5 cells and was reproduced twice more using the original specimen in MRC-5 cells, while inoculated A549 cells were unaffected.Cells from the primary MRC-5 cell culture exhibiting a CPE were trypsinized and fixed to slides for examination by fluorescent-antibody (FA) testing by two separate laboratories