Biomedical subjects
W E Farrar
Publications and source records attributed to W E Farrar.
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.
Antibiotic resistance in developing countries.
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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.
Molecular analysis of plasmids in epidemiologic investigation.
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Resistance of Listeria to cefotaxime and moxalactam.
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Reversible neutropenia from vancomycin.
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Hemorrhagic cystitis and ureteritis, and interstitial nephritis associated with administration of penicillin G.
Hemorrhagic cystitis and ureteritis, and interstitial nephritis developed in a patient receiving penicillin G and streptomycin as therapy for bacterial endocarditis. After therapy was changed to vancomycin there was prompt resolution of these abnormalities.
Transposable plasmid deoxyribonucleic acid sequence in Pseudomonas aeruginosa which mediates resistance to gentamicin and four other antimicrobial agents.
A 9.1 x 10(6)-dalton transposable deoxyribonucleic acid sequence resides within Pseudomonas aeruginosa plasmid R1033 and mediates resistance to gentamicin, streptomycin, sulfamethoxazole, chloramphenicol, and mercuric chloride. Transposability was demonstrated in Escherichia coli when this sequence, designated Tn1696, excised from R1033 and integrated into plasmid pMB8. Excision and insertion of Tn1696 occurred independently of the host Rec phenotype and may involve the 140-base pair, inverted deoxyribonucleic acid repeated region that flanks this sequence. Occurrence of a multiresistance transposon on a transferrable plasmid that has a broad host range may have serious epidemiological and therapeutic consequences.
Evolution of multiple-antibiotic-resistance plasmids mediated by transposable plasmid deoxyribonucleic acid sequences.
Two plasmid deoxyribonucleic acid sequences mediating multiple antibiotic resistance transposed in vivo between coexisting plasmids in clinical isolates of Serratia marcescens. This event resulted in the evolution of a transferable multiresistance plasmid. Both sequences, designated in Tn1699 and Tn1700, were flanked by inverted deoxyribonucleic acid repetitions and could transpose between replicons independently of the Excherichia coli recA gene function. Tn1699 and Tn1700 mediated ampicillin, carbenicillin, kanamycin, and gentamicin resistance but differed in the type of gentamicin-acetyltransferase enzymes that they encoded. The structural genes for these enzymes share a great deal of polynucleotide sequence similarity despite their phenotypic differences. The transposition of Tn1699 and Tn1700 to coresident transferable plasmids has contributed to the dissemination of antibiotic resistance among other gram-negative bacteria. These organisms have recently caused nosocomial infections in epidemic proportions.
Antibiotic resistance in intestinal bacteria.
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Comparative beta-lactamase resistance and antistaphylococcal activities of parenterally and orally administered cephalosporins.
Two parenterally administered cephalosporins (cephalothin and cephapirin) and four orally administered cephalosporins (cephalexin, cephradine, cefatrizine, and cefaclor) were investigated by use of 29 beta-lactamase-producing strains of Staphylococcus aureus for determination of their relative rates of hydrolysis (RH) by beta-lactamase (RH of penicillin G =100) and their antistaphylococcal activities. Cephalothin (RH less than 0.01) and cephapirin (RH = 0.1) were relatively stable in the presence of staphylococcal beta-lactamase. Cephalexin and cephradine (RH of each = 0.3) were less stable than cephalothin and cephapirin but more stable than cefatrizine (RH = 1.4) and cefaclor (RH = 3.4). Agents that were more resistant to hydrolysis were affected less by the size of the inoculum when tested against large ;(10(7)) and small (10(3)) inocula of beta-lactamase-producing staphylococci than those that were hydrolyzed rapidly. Cephalothin and cephapirin were four to eight times more active than the orally administered cephalosporins against 10(3) staphylococci. Cephalosporins that are relatively stable in the presence of staphylococcal bata-lactamase may be preferable to less stable ones for treatment of serious infections due to beta-lactamase-producing staphylococci.
Treatment of Nocardia asteroides infection with trimethoprim-sulfamethoxazole.
Although sulfonamide therapy has reduced the case fatality rate in infection due to Nocardia asteroides from nearly 100% to 25% to 45% there remains a need for a still more effective chemotherapeutic regimen. We describe three cases of serious infection due to N asteroides treated successfully with trimethoprim-sulfamethoxazole (TMP-SMX) and review an additional 15 cases from the world literature. Trimethoprim and sulfamethoxazole exhibit a synergistic interaction in vitro against N asteroides, and the agent reaches antibacterial concentrations in blood, lung, and the central nervous system. Clinical results have been satisfactory in the limited number of patients treated to date.