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Biomedical subjects

A C Lewis

Publications and source records attributed to A C Lewis.

29 records · Page 2Linked to original sources

Cefamandole therapy in anaerobic infections.

Thirty-one adult patients with infections due to anaerobic bacteria were treated with cefamandole. Bacteroides fragilis group (17) and Bacteroides melaninogenicus (13) were the most frequent anaerobes isolated. Duration of therapy varied from 2 to 49 days. Results were judged satisfactory in 26 cases, and unsatisfactory in 1 case. Four cases could not be evaluated. Adverse reactions occurred in 16 patients and included positive direct Coombs' test without hemolysis, transient liver function abnormalities, phlebitis, reversible neutropenia, fever, eosinophilia, and toxic epidermal necrolysis. The more significant reactions were associated with prolonged therapy. None was lethal. These data suggest that cefamandole is effective in treatment of most anaerobic infections.

Adult↗

Metronidazole in the treatment of anaerobic infections.

Using metronidazole in oral dosages of 1.5 to 2 g daily, we treated 13 adults who had anaerobic pleuropulmonary infections, including 11 with lung abscess, one with necrotizing pneumonia, and one with thoracic empyema. Five patients (four with lung abscess and one with necrotizing pneumonia) were cured. The lung abscesses of 5 patients did not respond. For 3 patients (one with epigastric distress who refused metronidazole, one with undrained empyema, and one who died while receiving metronidazole), therapy could not be evaluated. Side effects included leukopenia (2 patients), leukopenia and neutropenia (one), neutropenia (one), dark urine (two), bitter taste (two), and epigastric distress (one). In light of our findings, metronidazole is not uniformly effective in the treatment of anaerobic pleuropulmonary infections.

Adult↗

Analysis of increasing antibiotic resistance of Klebsiella pneumoniae relative to changes in chemotherapy.

Three antibiotic-resistant strains of Klebsiella pneumoniae responsible for outbreaks of systemic infection in a hospital nursery were analyzed. Each organism emerged after prolonged use of a drug to which it was resistant. The first strain (RO16) produced neomycin phosphotransferase and contained three plasmids with molecular weights of 24, 25, and 30 X 10(6) daltons, respectively. Resistance to ampicillin, carbenicillin, neomycin, and kanamycin was transferred by conjugation at a frequency of 10(-6). The second strain of K. pneumoniae (RO106) produced gentamicin adenyltransferase and maintained aminoglycoside resistance only when propagated in antibiotic-containing medium. DNA analyses revealed eight species of plasmid DNA: one species with a molecular weight of 70 X 10(6) daltons apparently accounted for conjugal transfer of resistance to ampicillin, carbenicillin, chloramphenicol, and streptomycin. The third strain (RO180) was resistant primarily to colistin and lacked plasmids. Control of the outbreak due to this strain was achieved by aminoglycoside therapy.

Aminoglycosides↗

Biochemistry of Vibrio cholerae virulence: purification of cholera enterotoxin by preparative disc electrophoresis.

Procedures for cholera enterotoxin purification previously developed in this labarotory were not applicable to large-scale purification, and these methods resulted in low yields of pure toxin. An efficient scheme has been developed whereby pure cholera enterotoxin can be obtained from 6 to 8 liters of culture supernatant fluid. This method consists of concentration by membrane ultrafiltration followed by gel filtration and cation-exchange chromatography. Pure cholera enterotoxin of high biological potency was obtained after a final step of preparative acrylamide gel electrophoresis. The degree of purity of the toxin-antigen as well as its biological activity were determined at various setps of purification. This alternate technique for purification is offered because of the widespread interest in cholera enterotoxin as a specific stimulator of adenyl cyclase.

Animals↗

Separation of type 2 toxins of Vibrio cholerae.

Choleragenic toxin was separated from vascular permeability factor by ion-exchange chromatography of supernatants of dialyzed peptone cultures of Vibrio cholerae. The choleragenic toxin eluted from columns of QAE-Sephadex with low-ionicity systems is free of permeability factor activity. Further elution of these columns with 0.5M NaCl removes both the permeability factor and residual choleragenic toxin. When this latter material is chromatographed on columns of carboxymethyl-Sephadex, the permeability factor toxin is eluted by 0.02M phosphate buffer and is free of choleragenic activity. Therefore, choleragenic and permeability factor activities of the type 2 cholera toxins are different and can be separated by these procedures.

Animals↗