Evidence of an association between Chlamydia pneumoniae and cerebrovascular accidents.

The authors report results of a retrospective pilot study showing a strong association between patients with stroke/TIA and the presence of circulating IgG and IgA antibodies to Chlamydia pneumoniae. These results support the hypothesis that chronic active or persistent infection may play a role in the mechanism of thrombosis. The risk for stroke associated with Chlamydial circulating antibodies appeared to be independent of other risk factors such as diabetes and hypercholesterolemia.

Waterhouse-Friderichsen syndrome after infection with group A streptococcus.

We report a case of Waterhouse-Friderichsen syndrome associated with group A streptococcus (GAS) toxic shock syndrome in a previously healthy man. The patient presented with neck pain and fevers of 2 days' duration. Computed tomography of the neck revealed a mass in the retropharyngeal space, suggesting an abscess. Despite prompt treatment with appropriate antibiotics, the patient experienced a fulminant course and died within 8 hours of presentation. Antemortem blood cultures grew GAS positive for exotoxins A, B, and C. Postmortem examination revealed bilateral adrenal hemorrhage, consistent with Waterhouse-Friderichsen syndrome. Immunohistochemical analysis of the adrenal glands revealed the presence of GAS antigens. However, no disseminated intravascular coagulation was evident. This case demonstrates that adrenal hemorrhage can occur without associated coagulopathy and may result directly from the action of bacterial toxins.

Disseminated cutaneous Pseudallescheria boydii.

As increasingly aggressive chemotherapeutic regimens are used to treat malignancy, more patients will become susceptible to various opportunistic pathogens. Specifically, several fungal organisms previously viewed as relatively non-pathogenic are more frequently causing serious disease in these patients. Identification of these organisms is of paramount importance, as some are relatively resistant to standard antifungal therapies. We report a patient with disseminated cutaneous Pseudallescheria boydii, diagnosed from histopathological examination and culture of a skin biopsy specimen. Identification of the organism was achieved shortly before the patient died. Clinicians must be aware of the numerous emerging opportunistic pathogens, which may require special culture techniques for diagnosis and varied or combined modes of therapy.

Experimental studies of the pathogenesis of Pseudomonas aeruginosa infection: evidence for the in-vivo production of a lethal toxin.

Evidence is presented that a lethal toxin is produced by P. aeruginosa growing in the burned skin of experimental mice. After injection of approximately 100 P. aeruginosa cells into the burned skin there was a rapid proliferation of organisms at the site of inoculation. When the organisms in the burned skin tissue reached a critical concentration, there was generalised toxaemia with subsequent mortality; the process was not reversible at this stage, even by reducing substantially the numbers of infecting organisms. However, when the reduction was accompanied by administration of rabbit serum prepared against filter-sterilised extracts of infected burned tissues, approximately 40% of the animals survived for at least 96 h. The data suggests that the antiserum afforded protection by inactivating a toxin produced by the organisms growing in the infected burned tissues rather than by further reducing the numbers of infecting organisms.

Experimental studies of the pathogenesis of infections due to Pseudomonas aeruginosa: description of a burned mouse model.

An experimental burned mouse model is described that is clinically relevant to burn wound sepsis caused by Pseudomonas aeruginosa. Mice subjected to a nonlethal burn by flame were challenged with P. aeruginosa. The LD50 after subcutaneous injection in the skin of the burn up to 24 hr after the burn was smaller than 10 organisms vs. 10-6 organisms in normal animals. By three days after the burn, the value returned to and exceeded that of normal animals. This dramatic change in the LD50 after the burn was not seen when mice were challenged with other organisms. Challenge with P. aeruginosa by different routes immediately after burning showed less dramatic decreases in the LD50. Enumeration of infecting organisms in the skin of the burn and in major organs suggests the possibility of a toxic event.

Speciation and amphotericin B sensitivity studies on blood isolates of Candida from burned patients.

Methods of speciating Candida isolates from clinical specimens are described and the necessity of speciation is emphasized. Differences in susceptibility of C. albicans and C. tropicalis to amphotericin B were observed and the implications of this in relation to treatment with amphotericin B and the development of resistance are discussed.