Rothia dentocariosa endocarditis complicated by perivalvular abscess.

A 35-year-old man with a history of intravenous drug use developed endocarditis due to Rothia dentocariosa that was complicated by a perivalvular abscess. Despite combined medical and surgical treatment, abscess formation progressed following aortic valve replacement, and the patient died during a second operative procedure. This is the sixth case of Rothia dentocariosa endocarditis reported in the English-language literature, and to our knowledge, the only case in which a perivalvular abscess has been documented.

Case report: phaeohyphomycosis due to Curvularia lunata involving skin and subcutaneous tissue after an explosion at a chemical plant.

Cases of phaeohyphomycosis due to dematiaceous fungi have been reported in increasing numbers and diversity. The optimal roles of antifungal chemotherapy and surgical debridement in the management of these infections have not been determined. A case of acute cutaneous and subcutaneous phaeohyphomycosis due to Curvularia lunata after an explosion at a chemical plant is reported, in which the organisms may have been inoculated into the tissues by the force of the blast. No organisms were found by histopathologic examination or culture of excisional biopsy specimens taken 10 days after initiation of therapy with intravenous amphotericin B; the antifungal therapy may have eradicated the infection.

Phaeohyphomycosis due to Exophiala species: clinical spectrum of disease in humans.

Phaeohyphomycosis caused by Exophiala species is an unusual infection, but it has been reported with increasing frequency as immunosuppressive therapy has become more widespread and laboratory methods for diagnosis have improved. To our knowledge, the first case of subcutaneous phaeohyphomycosis due to Exophiala jeanselmei in a cardiac transplant patient is presented, and previously reported cases of exophiala infection are reviewed. This patient was successfully managed with surgical excision of the lesion and combination therapy with amphotericin B and 5-fluorocytosine.

Erysipelothrix rhusiopathiae: an occupational pathogen.

Erysipelothrix rhusiopathiae is a nonsporulating, gram-positive, rod-shaped bacterium which was identified more than 100 years ago as the etiologic agent of swine erysipelas. Since then, it has been found to cause infection in several dozen species of mammals and other animals. Humans become infected through exposure to infected or contaminated animals or animal products. By far the most common type of human infection is a localized, self-limited cutaneous lesion, erysipeloid. Diffuse cutaneous and systemic infections occur rarely. Approximately 50 cases of endocarditis have been reported; all but one recent case have involved native valves. The organism may be isolated from biopsy or blood specimens on standard culture media. It is identified by morphology, lack of motility, and biochemical characteristics; identification may be confirmed by the mouse protection test. It is susceptible to penicillins, cephalosporins, erythromycin, and clindamycin, but it is often resistant to many other antibiotics, including vancomycin, a drug frequently used in empiric therapy for infections due to gram-positive bacteria.

Bacteremia and infection of a hip prosthesis caused by Bacillus alvei.

Of the 34 Bacillus species described, 10 have been reported to cause infection in humans and 6 are insect pathogens. We report a case of an infected prosthetic hip caused by Bacillus alvei, only the third documented case of human infection with this organism.

Bacteremia and ecthyma caused by Streptococcus pyogenes in a patient with acquired immunodeficiency syndrome.

Ecthyma is an ulcerated form of impetigo due to Streptococcus pyogenes, seen primarily in children with poor hygiene. The authors report a homosexual man with acquired immunodeficiency syndrome (AIDS) who developed severe ecthyma and bacteremia caused by S. pyogenes. Opsonizing antibody to the M protein of S. pyogenes is important in immunity to this organism. Patients with AIDS may have defective humoral immunity as well as defective cellular immunity, and such a defect may have rendered this patient abnormally susceptible to severe infection with S. pyogenes.

Fatal cardiac tamponade in a young man with group C streptococcal endocarditis.

The case of a previously healthy man with endocarditis due to the group C streptococcus, complicated by myocardial abscess and fatal cardiac tamponade, is presented. Group C streptococcus is an unusual cause of endocarditis which tends to produce extensive valve destruction. Early surgery should be considered in patients with endocarditis caused by this organism.

Usefulness of computerized tomography in evaluating necrotizing fasciitis.

A 54-year-old man was seen with what appeared to be cellulitis of the left lower extremity. Roentgenograms showed no evidence of gas in soft tissues. Two days later films revealed gas in soft tissues of the leg, but not in the thigh. Computerized tomography showed pockets of gas in the lateral fascial planes of both leg and thigh. Surgical exploration revealed extensive necrotizing fasciitis. CT scanning provided a much more accurate picture of the extent of infection than did standard radiographs.

Amdinocillin in combination with beta-lactam antibiotics for treatment of serious gram-negative infections.

Amdinocillin in combination with another beta-lactam antibiotic (ampicillin, cephalothin, cefamandole or cefoxitin) was used to treat 25 patients with pyelonephritis (with or without bacteremia), pneumonia, bacteremia secondary to intravenous devices, and urinary tract infections (with catheter in place) due to gram-negative organisms. The combination resulted in a clinical response in 96 percent of the patients and a bacteriologic response in 100 percent at 72 hours. Few toxic effects were seen. At long-term follow-up, relapse occurred in three of 10 patients with pyelonephritis who were treated with a combination regimen and completed their course of antimicrobial therapy with a beta-lactam antibiotic. Reinfection occurred in one patient who had a urinary tract infection with a catheter in place. In vitro testing showed that the cefamandole-amdinocillin combination most frequently produced synergy against the strains of Escherichia coli isolated. Synergy with the antibiotic combinations was also seen against strains of Klebsiella pneumoniae. It was difficult to correlate the in vitro test results with the in vivo therapeutic effect of these antibiotic combinations.

Investigation of nosocomial infections by plasmid analysis.

Molecular biological techniques, including agarose gel electrophoresis, restriction endonuclease analysis and DNA-DNA hybridization (Southern blotting and heteroduplex analysis) are being applied very successfully to the investigation of nosocomial infections. 'Plasmid fingerprinting' by electrophoresis, with or without restriction endonuclease analysis, can be used to identify epidemic strains of bacteria and 'epidemic plasmids' which have spread through several different bacterial species. This technique is rapid and inexpensive, and can be applied to drug-sensitive as well as resistant strains. This approach is especially useful for investigation of organisms for which no standard typing system is available. DNA-DNA hybridization techniques can be used to study the evolution of plasmids in the hospital environment, and to demonstrate the presence and spread of translocatable DNA sequences (transposons) carrying drug resistance determinants from plasmid to plasmid within a bacterial cell.

Evolution of a plasmid mediating resistance to multiple antimicrobial agents during a prolonged epidemic of nosocomial infections.

At the Vanderbilt University Medical Center, Nashville, Tennessee, resistance to gentamicin was encountered with increasing frequency among several species of gram-negative bacilli between 1973 and 1977. Representative strains were screened for plasmid DNA content using agarose gel electrophoresis. In strains of Pseudomonas aeruginosa and Serrati marcescens isolated early in the outbreak, gentamicin resistance was mediated by a common 9.8-megadalton nonconjugative plasmid. Either an 80- or a 100-megadalton transferable plasmid coexisted with the nonconjugative plasmid in the isolates of Serratia. Transposition between the 100- and 9.8-megadalton plasmids in this species resulted in the formation of a 105-megadalton conjugative plasmid that mediated gentamicin resistance; this was observed in strains of Serratia and Klebsiella isolated in 1976-1977. Thus, during this five-year investigation separate outbreaks of nosocomial infections that were caused by different bacterial species were shown to be related by the presence of plasmids that contained a common transposable DNA sequence.