Herrmann, Ernest C.

Certain antibiotics, if in serum, simulate specific antibody in the metabolic inhibition test for diagnosis of Mycoplasma pneumoniae infections. This effect is not eliminated by presence of serum or heat treatment.

Herpes simplex and vaccinia viruses and adenovirus types 1, 2, 5, and 7 were tested by plaque suppression methods for sensitivity to halogenated deoxyuridines (5-iodo-, 5-bromo-, 5-chloro-, and 5-fluoro-), cytosine arabinoside, isatin-β-thiosemicarbazone, and N -methylisatin-β-thiosemicarbazone. After incubation for 12 days in HeLa cell cultures, vaccinia virus plaques were still readily suppressed by deoxyribonucleic acid (DNA) inhibitors and thiosemicarbazones. Herpes simplex virus plaques were likewise suppressed by at least three DNA inhibitors. Adenovirus plaques were not suppressed by DNA inhibitors or thiosemicarbazones. 5-Fluoro-2′-deoxyuridine could not be shown to have any antiviral activity, but it did produce a substantial lethal action on the cells.

The sensitivities of 21 strains of herpes simplex virus (HSV), 13 type 1 strains and 8 type 2 strains, to 5-iodo-2′-deoxyuridine (IUdR) and 9-β- d -arabinofuranosyladenine (ara-A) were evaluated by the plaque-suppression test in chick embryo fibroblast (CEF), WI-38, and HeLa cell cultures. In CEF, type 1 strains were considerably more sensitive to the inhibitors than were the type 2 strains. In WI-38, the type 1 strains were more sensitive than the type 2 strains to IUdR; however, the two serotypes were equally sensitive to ara-A. In HeLa cells, the differences in sensitivity to IUdR between the two serotypes were less. Eight HeLa-adapted strains (four type 1 and four type 2) evaluated in HeLa cell cultures were equally sensitive to IUdR; the type 2 strains were slightly more sensitive than type 1 strains to ara-A. These results demonstrate the wide variation in sensitivity of HSV types 1 and 2 to antiviral agents which results from differences in the cell culture system and passage history of the strains.

Summary The shortcomings of the methods commonly recommended for the diagnosis of viral infections are emphasized. Most of them are laborious and expensive, and are of very little practical value to the clinician. Nine years’ experience has confirmed that the use of a single swab, obtained during the acute stage of the illness, for bacterial culture and viral isolation (looking for cytopathic effects or haemadsorption) provides the diagnosis quickly in the great majority of viral infections.