Intracellular bacteria have been described in several species of filarial nematodes, but their relationships with, and effects on, their nematode hosts have not previously been elucidated. In this study, intracellular bacteria were observed in tissues of the rodent parasite Litomosoides sigmodontis by transmission electron microscopy and by immunohistochemistry using antiendobacterial heat shock protein-60 antisera. Molecular phylogenetic analysis of the bacterial 16S ribosomal RNA gene, isolated by PCR, showed a close relationship to the rickettsial Wolbachia endobacteria of arthropods and to other filarial intracellular bacteria. The impact of tetracycline therapy of infected rodents on L. sigmodontis development was analyzed in order to understand the role(s) these bacteria might play in filarial biology. Tetracycline therapy, when initiated with L. sigmodontis infection, eliminated the bacteria and resulted in filarial growth retardation and infertility. If initiated after microfilarial development, treatment reduced filarial fertility. Treatment with antibiotics not affecting rickettsial bacteria did not inhibit filarial development. Acanthocheilonema viteae filariae were shown to lack intracellular bacteria and to be insensitive to tetracycline. These results suggest a mutualistic interaction between the intracellular bacteria and the filarial nematode. Investigation of such a mutualism in endobacteria-containing human filariae is warranted for a potential chemotherapeutic exploitation.

To analyze the frequency of intra-abdominal Candida infection during acute necrotizing pancreatitis and to compare the outcome to patients without Candida infections. Retrospective analysis of data from 37 patients with and without Candida infection. Surgical intensive care unit (ICU) in a university hospital. Thirty-seven patients with acute necrotizing pancreatitis. Patients were subject to necrosectomy and programmed lavage. Clinical parameters contained in the Acute Physiology and Chronic Health Evaluation (APACHE) II score were monitored, as were microbiological results from the intra-abdominal primary focus and from sites of secondary infections. Body mass index, distribution of underlying diseases, length of ICU stay, number of operations, and outcome were recorded. Multivariate logistic regression analysis for mortality as the dependent variable was performed. Intra-abdominal Candida infection was observed in 13 of 37 cases and was associated with a four-fold greater mortality rate compared with intra-abdominal bacterial infection alone. Multivariate logistic regression analysis demonstrated that Candida infection contributed to mortality significantly (p < .025) and independently from APACHE II (p < .006; mortality odds ratio for the two parameters = 12.5). Lack of antimycotic treatment was associated with an increase to 29.2 (p < .001) in the odds ratio. Given the impact of Candida infection on mortality to acute necrotizing pancreatitis and the apparent benefit from antimycotic chemotherapy, the data argue for an early fungicide chemotherapeutic intervention. (Crit Care Med 1998; 26:2010-2015)