Allergic hypersensitivity to neomycin. Relationship between patch test reactions and 'use' tests

The prevalence of neomycin patch test sensitivity in the general population is approximately 1%. We describe the relationship between positive neomycin patch tests and clinical "use tests" with two antibiotic combinations (Neosporin G cream and Neosporin ointment). The neomycin use test was positive in seven of eight subjects with a strongly positive patch test, and in two of four subjects with a weakly positive patch test. A positive use test usually occurred earlier and was always more intense with the cream base. The use test reactions were usually mild even with continued application of the antigen. Use tests with commercial products may be helpful in evaluating the clinical relevance of positive patch tests.

Effect of occlusion on Trichophyton mentagrophytes infections in guinea pigs

The effect of occlusion and griseofulvin on the duration and severity of acute dermatophytosis was assessed in guinea pigs. Sixty guinea pigs given standard Trichophyton mentagrophytes infections were divided into 5 groups: (A) control, (B) intermittent wet occlusion, (C) continuous-wet occlusion, (D) griseofulvin, (E) griseofulvin-continuous-wet occlusion. Lesions were largest in the control group, smallest in the griseofulvin-continuous-occlusion group, and of intermediate area in the other groups. The degree of inflammation and alopecia was not affected by occlusion, but was markedly reduced or eliminated with griseofulvin. Healing of the lesions occurred more rapidly in the griseofulvin-continuous-occlusion group than in any other group. This study suggests that either occlusion of the inoculated site or oral griseofulvin markedly reduces the expected area of the fungal lesion, and occlusion together with griseofulvin shortens the duration of the lesion.

Occlusion, carbon dioxide, and fungal skin infections

Occlusion of the skin renders it susceptible to acute fungal skin infections (dermatophytosis and candidiasis). Occlusion also raised carbon-dioxide (CO2) tensions at the skin's surface. Comparable CO2 tnesions have a pronounced effect on the morphology and metabolism of dermatophytes in vitro. It is postulated that dermatophyte conida and hyphae produce infective units under conditions of raised CO2 tensions, and that occlusion of the skin produces the concentrations of CO2 required for the conversion. Fungal skin infections might be prevented or controlled by interference with the action of CO2 or by prevention of its accumulation under wet, occlusive clothing.

Serodiagnosis of hepatitis B virus infection by antibody to core antigen

In a military population antibody to hepatitis B core antigen (anti-HBc) was found in 39% of acute hepatitis cases negative for hepatitis B surface antigen (HBS Ag) and in 96% of HBs Ag-positive cases. Persistence of antibody to HBs Ag (anti-HBs) in convalescent-phase sera was significantly greater (P less than 0.001) in individuals with acute HBs Ag-positive hepatitis B than in patients with clinical HBs Ag-negative hepatitis B. The prevalence of anti-HBc in the absence of HBs Ag, anti-HBs, and clinical disease was 3.2% in this military population. In longitudinal studies of hepatitis B infection, the presence of anti-HBc preceded anti-HBs and improved the ability to determine the onset of sublicnical infection. Anti-HBc is a useful serologic marker for the study of the epidemiology of hepatitis B and improves the efficiency of detection of hepatitis B virus infection.

Effects of prolonged continuous exposure of human skin to water: a reassessment

Continuous exposure of human skin to water in small plastic cups for periods of 72 and 144 hr produced a mild, transient dermatitis in half the sites tested. The degree of dermatitis was only slightly greater at 144 than at 72 hr, and was unrelated to the pH of the water samples. Comparison of soap-pretreated to non-pretreated skin areas showed a significant tendency for the more severe dermatitis to be present on the non-pretreated skin areas at higher pH's. There was virtually no coating of hairs with waxy yellowish material (clumps of bacteria), and no lesion was produced that resembled warm-water-immersion injuries.

Persistence of antibody to hepatitis B surface antigen

Sera from military personnel found to have antibodies to hepatitis B surface antigen (anti-HBS) in an epidemiological study of a hepatitis B outbreak were tested for persistence of that antibody 1 year later. Initially, 64% of the anti-HBS-positive sera reacted in passive hemagglutination tests with erythrocytes coated with hepatitis B surface antigen of both ayw and adw subtypes; the remaining sera reacted only with adw-coated erythrocytes (19%) or ayw-coated erythrocytes (17%). After 1 year, anti-HBS was detectable by passive hemagglutination tests in 87% of individuals with initial antibody to both subtypes but in only 41% and 16% (P less than 0.001) of those initially reacting only to adw- or ayw-coated erythrocytes, respectively. Seropositivity for anti-HBS correlated best with history of contact with jaundiced people (20.3%) and duty in Asia.

Epidemic hepatitis B: a sustained outbreak in a large military population

A sustained outbreak of viral hepatitis occurred at an Army base in Texas between January 1971 and June 1973. Seven hundred ninety-two admissions but no deaths were recorded in a military population of 35,000. Cases were sporadic, with highest attack rates in low-ranking soldiers with disciplinary problems. Twenty-nine per cent of patients had histories of intravenous drug use within six months prior to hospitalization; most of the rest had close personal contact with jaundiced persons. Of 505 patients tested, 31% were seropositive for hepatitis B antigen (HBSAg) by counterelectrophoresis. Comparison of 38 hepatitis patients (cases) to 34 orthopedic patients (controls) revealed marked differences in rates of exposure to jaundiced persons are shared needles. Sixteen (94%) of 17 antigenemic cases tested were of subtype ayw. Seven (78%) of nine NBSAg-negative cases tested were antibody (anti-HBS) positive three months later.

Hepatitis B antigen in saliva, urine, and stool

A survey of hepatitis B patients, asymptomatic hepatitis B antigen (HBsAg) carriers, and control subjects was conducted to determine the relationship between antigenemia and antigen excretion in saliva, urine, and stool. Radioimmunoassay was used to detect HBsAg. Specificity-confirmed HBsAg was detected in the saliva of 6 (30%) of 20 antigenemic patients, 1 (5%) of 20 nonantigenemic patients, 14 (34%) of 41 carriers, and 0 of 112 controls. HBsAg was detected in urine only after 100-fold concentration of first-morning specimens. Specificity-confirmed HBsAg was present in the urine of 7 (16%) of 43 carriers; unconfirmed HBsAg was found in the urine of 5 (13%) of 38 patients and 5 (5%) of 112 controls. Unconfirmed HBsAg was detected in concentrated stool specimens from 5 (46%) of 11 patients and 3 of 8 carriers and controls. Longitudinally collected specimens from antigenemic subjects showed no consistent patterns of antigen excretion.

Specificity and sensitivity of radioimmunoassay for hepatitis B antigen

Sera from a survey of 6,026 people were tested for hepatitis B surface antigen by using radioimmunoassay and counterelectrophoresis. Forty-eight sera (0.79%) were positive by counterelectrophoresis and 152 sera (2.52%) were positive by radioimmunoassay, using the most liberal of the recommended criteria for positivity (i.e., counts 3 standard deviations above the mean). Absorption tests performed on the 152 radioimmunoassay-positive sera showed that 10 (6.6%) were false-positive reactions to guinea pig protein, 74 (48.6%) were due to false-positive reaction(s) with other protein(s) in the test system, and 68 (44.8%) were true positives. There was a strong correlation between the degree of elevation of radioactive counts and the proportions of sera that were true positives; all 49 sera with counts >50 standard deviation units above the mean were true positives, but only 19 (18.4%) of the 103 sera with counts <50 standard deviation units were true positives. A few sera with high counts required absorption with type-specific (type D) antisera. The following conclusions were reached from this study: (i) absorption tests should be run on all radioimmunoassay-positive, counterelectrophoresis-negative sera; (ii) most (about 90%) false positives are not due to anti-guinea-pig protein reactions; and (iii) radioimmunoassay, in combination with absorption tests, yields a modest increase (about 35%) in detection of true positives over use of counterelectrophoresis alone.

Skin infections in eastern Panama. Survey of two representative communities

A skin infection survey of 1,084 people was carried out in two jungle villages in eastern Panama. Bacterial pyoderma was the most prevalent infection, affecting 25% of boys, 15% of girls, and 11% of those over 10 years of age. Streptococcus pyogenes and Staphylococcus aureus were recovered from 84% of pyodermas cultured. Nearly 60% of the cutaneous staphylococcal isolates were resistant to penicillin. Hippelates flies were seen feeding on purulent skin lesions and may have been important in transmission. Scabies, ringworm, candidiasis, and cutaneous leishmaniasis were in comparison with pyoderma involving less than 1% of the population each. All of the ringworm infections were caused by Trichophyton rubrum.

Tyzzer's disease

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Tyzzer's Disease of Rabbits: Isolation and Propagation of Bacillus piliformis (Tyzzer) in Embryonated Eggs

Bacillus piliformis (Tyzzer) was isolated from the liver of rabbits with Tyzzer's disease and serially passaged in embryonated hens' eggs. Weanling rabbits given the 32nd egg passage developed lesions typical of Tyzzer's disease and died. B. piliformis was reisolated from the liver of these rabbits in embryonated eggs. Outside the host cell, the motile vegetative phase appeared to be unstable, and no means was found to preserve its viability; the results of titrations were believed to be dependent upon the resistant stage or spore. The spore withstood repeated freeze and thaw and was resistant to heat treatment of 56 C for 1 hr but not 80 C for 0.5 hr. None of several antibacterial substances tested in embryonated eggs was completely inhibitory; B. piliformis was resistant to sulfamethazine and chloramphenicol. The taxonomic position of this pleomorphic, gram-negative, sporeforming, pathogenic bacterium which appears to grow only in certain cells of several species remains unresolved.

Tyzzer's Disease Syndrome in Laboratory Rabbits

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