Delayed-type hypersensitivity skin testing in human immunodeficiency virus-infected pediatric patients.

OBJECTIVE: To evaluate whether pediatric patients infected with human immunodeficiency virus (HIV) can mount appropriate delayed-type hypersensitivity (DTH) skin responses to recall antigens and whether these responses can be correlated with clinical or immunologic parameters. DESIGN: Prospective evaluation of DTH responses in HIV-infected children. Uninfected children born to HIV-infected mothers served as control subjects. Antigens used for yearly DTH testing included Candida albicans (1:100, 1:10); mumps virus; Trichophyton; purified protein derivative of tuberculin; and tetanus toxoid (1:100, 1:10). At the time of each DTH test, patients were staged according to two Centers for Disease Control and Prevention pediatric HIV classification systems, and T-cell subsets were obtained. RESULTS: Twenty-seven HIV-infected patients with a median age at entry of 74.1 (range, 12 to 156) months were followed. Forty-four DTH skin tests in 21 symptom-free HIV-infected patients (PI) and 18 tests in 10 HIV-infected patients with symptoms (P2), as well as 43 DTH skin tests in 18 patients who had either mild or moderate clinical symptoms or immunosuppression and 19 tests in 13 patients with severe symptoms or immunosuppression, were evaluated. Sixteen DTH skin tests were performed in 14 uninfected patients. HIV-infected patients tended to have fewer DTH responses to antigens and of smaller size than did uninfected patients. When controlled for age, few differences in DTH responsiveness were seen between HIV-infected and uninfected patients. Anergy was associated with symptomatic disease, evidence of advanced clinical or immunologic disease, and low CD4+ percentages (p <0.05). CONCLUSIONS: HIV-infected children are able to mount antigen-specific cell-mediated immune responses that are qualitatively similar to those of age-matched control subjects. Loss of DTH responsiveness correlates with both clinical and immunologic evidence of HIV disease progression.

Serious infections involving the CDC group Ve bacteria Chryseomonas luteola and Flavimonas oryzihabitans.

Chryseomonas luteola and Flavimonas oryzihabitans are phenotypically similar gram-negative bacilli and are also referred to as CDC groups Ve-1 and Ve-2, respectively. These bacteria are rarely reported as pathogens in humans. Infections described in the literature include primarily bacteremia in critically ill patients and peritonitis in patients undergoing continuous ambulatory peritoneal dialysis. We describe three cases of polymicrobial infection secondary to infection with group Ve organisms, including the first reported case (to our knowledge) of CNS infection due to F. oryzihabitans. These three cases and a review of literature suggest an association between the presence of indwelling catheters and polymicrobial infections with CDC group Ve organisms. F. oryzihabitans and C. luteola should be added to the expanding list of nosocomial pathogens with a propensity to infect critically ill patients who have undergone surgical procedures and/or had indwelling catheters placed. The isolation of either of these organisms from clinical specimens should prompt a search for a device-related source.

Cat scratch disease.

In summary, CSD is a relatively common cause of localized lymphadenopathy, with 80 per cent of cases occurring in children. This self-limited infection is caused by a small pleomorphic bacillus that has been identified in ocular granuloma, skin, and lymph node specimens. Unusual manifestations of the disease such as the oculoglandular disease of Parinaud, encephalopathy, or severe systemic disease occur in about ten per cent of patients. Management consists of symptomatic treatment and occasionally aspiration of a node that suppurates. The disease usually resolves spontaneously in 2 to 4 months.

Rapid detection of group B streptococcal antigen in human amniotic fluid.

Infants exposed in utero to group B streptococcus (GBS)-infected human amniotic fluid (HAF) are at high risk for serious infection. Latex particle agglutination (LPA) tests are not approved for detection of GBS in HAF. Two LPA systems, Patho-Dx Strep B and Wellcogen Strep B, were used to test unfiltered sterile HAF and filtered HAF containing concentrations of GBS carbohydrate from 0.2 to 100 micrograms/ml. Four different processing techniques were used to prevent nonspecific LPA: EDTA, nitrous acid, enzyme, and nitrous acid-heat. GBS (10(2) CFU/ml) was inoculated into filtered HAF, incubated, sampled serially, processed with enzyme, and tested by LPA. Unprocessed, unfiltered HAF showed 33% nonspecific agglutination when tested by LPA. Processing of HAF removed nonspecific agglutination and improved GBS antigen detection. Without processing, LPA could not detect less than 100 micrograms of GBS carbohydrate per ml. With nitrous acid or enzyme processing, as little as 0.2 microgram/ml could be detected. Results were easier to read after enzyme processing than after nitrous acid processing. Although both LPA systems were equally efficient, testing was easier with the Patho-Dx system. After enzyme processing, LPA could detect as few as 10(4) CFU/ml when agglutination was read with a 4 X hand lens. Substances in HAF induce false-positive reactions during LPA testing. Processing removes the interference and improves the detection of GBS. LPA testing of HAF may allow earlier identification and treatment of infants at risk for serious GBS infection.