A prospective descriptive study of cryptococcal meningitis in HIV uninfected patients in Vietnam - high prevalence of Cryptococcus neoformans var grubii in the absence of underlying disease.

BACKGROUND: Most cases of cryptococcal meningitis occur in patients with HIV infection: the course and outcome of disease in the apparently immunocompetent is much more poorly understood. We describe a cohort of HIV uninfected Vietnamese patients with cryptococcal meningitis in whom underlying disease is uncommon, and relate presenting features of patients and the characteristics of the infecting species to outcome. METHODS: A prospective descriptive study of HIV negative patients with cryptococcal meningitis based at the Hospital for Tropical Diseases, Ho Chi Minh City. All patients had comprehensive clinical assessment at baseline, were cared for by a dedicated study team, and were followed up for 2 years. Clinical presentation was compared by infecting isolate and outcome. RESULTS: 57 patients were studied. Cryptococcus neoformans var grubii molecular type VN1 caused 70% of infections; C. gattii accounted for the rest. Most patients did not have underlying disease (81%), and the rate of underlying disease did not differ by infecting species. 11 patients died while in-patients (19.3%). Independent predictors of death were age > or = 60 years and a history of convulsions (odds ratios and 95% confidence intervals 8.7 (1 - 76), and 16.1 (1.6 - 161) respectively). Residual visual impairment was common, affecting 25 of 46 survivors (54.3%). Infecting species did not influence clinical phenotype or outcome. The minimum inhibitory concentrations of flucytosine and amphotericin B were significantly higher for C. neoformans var grubii compared with C. gattii (p < 0.001 and p = 0.01 respectively). CONCLUSION: In HIV uninfected individuals in Vietnam, cryptococcal meningitis occurs predominantly in people with no clear predisposing factor and is most commonly due to C. neoformans var grubii. The rates of mortality and visual loss are high and independent of infecting species. There are detectable differences in susceptibility to commonly used antifungal drugs between species, but the clinical significance of this is not clear.

The Role of Water in the Intercalation of Kaolinite with Potassium Acetate.

Water in intercalated kaolinites is observed first as bands inthe hydroxyl-stretching region at 3300 to 3550 cm-1 and bythe water H-O-H bending vibrations in the 1560 to 1680-cm-1 region. For potassium-acetate-intercalated kaolinite, hydroxyl-stretching bands attributed to water are observed at approximately 3540, approximately 3475, approximately 3430, and approximately 3380 cm-1. Water bending modes areobserved at 1560, 1586, 1610, and 1679 cm-1. These bands are attributed to (a) water molecules adsorbed on the kaolinite surface, (b) zeolitic water, (c) molecular first layer water, and (d) orderedwater on the hydroxyl surface, respectively. The intensities ofthe bands are a function of the method of preparation of the intercalated kaolinite. As the kaolinite was washed for varying time intervals, the 1560 cm-1 band decreased in intensity more rapidly than the 1610 cm-1 band. Even after washing for 24 h significant concentrations of water remained on the kaolinite and only heating removed the water. The 1560, 1586, and 1610 cm-1 bands are attributed (a) to free or non-hydrogen-bonded water held in the interlayer spaces of the kaolinite, (b) to water in the hydration sphere of the potassium ion, and (c) to surface-adsorbed water on the kaolinite layers. In kaolinites intercalated under pressure, an additional band was observed at 1679 cm-1. It is proposed that this band is due to water coordinated to the kaolinite surface. Copyright 1998 Academic Press.