Symptomatic lactic acidosis in hospitalized antiretroviral-treated patients with human immunodeficiency virus infection: a report of 12 cases

We retrospectively investigated the clinical and histopathologic features of hospitalized patients infected with human immunodeficiency virus who had symptomatic lactic acidosis syndrome at a university teaching hospital during 1995-2000. Twelve patients were identified, 11 during 1998-2000; of these, 5 died with rapid progression to otherwise unexplained multiple-organ failure. All had extensive prior exposure to nucleoside analog reverse-transcriptase inhibitors (NRTIs). At presentation, the most commonly identified NRTI component of antiretroviral regimens was stavudine plus didanosine. Eleven patients presented with abdominal pain, nausea, and/or emesis. Eight patients had prior acute weight loss (mean [+/-SD], 12+/-5.3 kg). Median venous plasma lactate levels were > or =2-fold greater than the upper limit of normal (2.1 mmol/L). Serum transaminase levels were near normal limits at presentation. Histopathologic studies confirmed hepatic macrovesicular and microvesicular steatosis in 6 patients. Concurrent chemical pancreatitis was identified in 6 patients. The increasing number of cases identified during the study period suggests that physicians better recognize symptomatic lactic acidosis and/or that cumulative NRTI exposure may increase the risk for this syndrome.

Endocarditis due to Actinomyces viscosus

We report a case of endocarditis caused by Actinomyces viscosus in a previously healthy young adult with no known identifiable portal of entry. Infective endocarditis caused by A viscosus is uncommon; two cases of endocarditis caused by this species have been previously reported. Primary actinomycotic endocarditis has been previously reviewed in 1993; we provide a review of additional cases since that report. In comparing our case with the other reported cases, we found that actinomycotic endocarditis (1) occurs in a wide spectrum of age, (2) affects primarily males, (3) has a high propensity for systemic embolization, and (4) has involved only native heart valves. The disease is manifested by the typical signs and symptoms of infective endocarditis and is curable with long-term penicillin therapy. The use of echocardiography in the diagnosis of endocarditis, techniques for improving the microbiologic diagnosis of endocarditis, and current indications for surgical intervention are discussed.

Gardnerella vaginalis: an unusual case of pyogenic liver abscess

We present a case of pyogenic liver abscess caused by Gardnerella vaginalis, a previously unreported suppurative complication of infection with this organism. The development of the pylephlebitis originating from endometritis and the possible synergistic interaction of an anaerobic and aerobic organism is reviewed. G. vaginalis has been infrequently isolated in the laboratory; perhaps with refined culturing techniques and recognition of the pathogenic potential of this organism, further cases of suppurative complications will be described.

Effects of physiologic variations in temperature on the rate of antibiotic-induced bacterial killing

The effects of physiologic temperature variations on antibiotic-induced killing of Escherichia coli, Pseudomonas aeruginosa, Streptococcus faecalis, and Streptococcus pneumoniae were studied. At concentrations less than or equal to four times the minimal bactericidal concentration, the activity of each of the antibiotics (gentamicin sulfate, sodium ampicillin, and chloramphenicol) against the test bacteria was influenced by changes in temperature. Only with S. pneumoniae did such influence appear to result directly from temperature-induced changes in the multiplication rate of the bacteria. Repeated subculturing of bacteria at 41 degrees C to induce temperature adaptation had a variable effect on the rate of bacterial killing by appropriate antibiotics. The magnitude of the effect of temperature on antibiotic-induced rates of bacterial killing varies with the antibiotic class, the species of bacteria, and the temperature to which bacteria have been adapted.