Effects of pentoxifylline or dexamethasone in combination with amphotericin B in experimental murine cerebral cryptococcosis: evidence of neuroexcitatory pathogenic mechanisms.

In a murine model of intracerebral infection by Cryptococcus neoformans the therapeutic effects of pentoxifylline or dexamethasone were studied alone and in combination with amphotericin B. Assessed parameters were mean survival time, brain histopathology index, amounts of glutamate and gamma-aminobutyric acid in the brain, and yeast CFU per brain. Survival increased significantly in mice treated with dexamethasone, amphotericin B, amphotericin B plus dexamethasone, and amphotericin B plus pentoxifylline; the latter had significantly longer survival than other treated groups. Indices of histopathological damage were similar in all treated groups. In infected untreated mice, the amounts of glutamate in the brain were decreased, presumably by depletion. In mice treated with amphotericin B plus dexamethasone, glutamate levels returned to the range of control mice. No differences in the amounts of gamma-aminobutyric acid were found between control and treatment groups. Brain fungal counts were significantly lower in mice treated with amphotericin B, amphotericin B plus dexamethasone, and amphotericin B plus pentoxifylline than in untreated animals. In this model, pentoxifylline in combination with amphotericin B improved survival, decreasing the fungal burden, and has potential as adjuvant therapy in cerebral cryptococcosis.

Cryptococcus neoformans var. gattii among patients with cryptococcal meningitis in Mexico. First observations.

A retrospective study of 20 patients with cryptococcal meningitis and their isolated strains was performed. Cryptococcus neoformans var. neoformans was recovered from 14 (70%) cases, and var. gattii was recovered from six (30%) patients. Twelve patients had AIDS (all carrying var. neoformans), two had other diseases (one with var. neoformans and one var. gattii) and there was no identifiable underlying disease in six (one var. neoformans and five var. gattii). Fourteen patients (11 var. neoformans and three var. gattii) resided in the Mexico City area, where a temperate climate is prevalent, and there were six cases (three var. neoformans and three var. gattii) from states with a tropical/subtropical climate. Although there was no significant statistical difference between the two varieties, the fatal outcome was higher in patients with var. neoformans. The disease caused by var. gattii strains was characterized by a higher opening pressure, more inflamatory changes of CSF and a longer clinical course (delayed clinical and mycological cure). Cryptococcus neoformans var. gattii is a significant cause of cryptococcal meningitis in patients without underlying diseases in Mexico.

[In vitro comparison of ciprofloxacin with other antibiotics against multiresistant gram-negative bacilli]. / Comparación in vitro de la ciprofloxacina con otros antibióticos contra bacilos gramnegativos multiresistentes.

In 2784 specimens submitted to the Clinical Microbiology Laboratory of the Instituto Nacional de Neurología from May 1989 to January 1990, 140 (5.0%) had gram negative bacilli (GNB) resistant to five or more antibiotics. One hundred different isolates recovered from urine, tracheal aspirates, blood, cerebrospinal fluid, surgical wound infections and other sites were studied. Pseudomonas spp, Enterobacter spp, Klebsiella pneumoniae and Escherichia coli accounted for 86% of the total. Disk diffusion susceptibility tests with the NCCLS method revealed 59 to 67% of isolates susceptible to amikacin, ciprofloxacin and ceftazidime. Sixteen to 30% were inhibited by piperacillin, cefoperazone and cefotaxime. Less than 10% were susceptible to carbenicillin, tobramycin, gentamicin, cephalothin and ampicillin. Minimum inhibitory concentrations (MIC) to amikacin and ciprofloxacin were determined by broth macrotube dilution in Mueller-Hinton broth supplemented with Ca and Mg ions with a 5 x 10(5) cfu/mL inocula. MIC of 16 ug/mL or less for amikacin was found in 39% of the isolates; MIC 50 was 32 ug/mL and MIC 90 greater than 64 ug/mL. Ciprofloxacin had MIC 50 of 1 ug/mL and an MIC 90 greater than 4 ug/mL. Higher MICs to ciprofloxacin were seen in Pseudomonas spp.