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Biomedical subjects

R M Echols

Publications and source records attributed to R M Echols.

At least 19 recordsLinked to original sources

Pharmacokinetic profiles of ciprofloxacin after single intravenous and oral doses.

Ciprofloxacin was administered to 12 healthy male volunteers at doses of 300 and 400 mg intravenously (i.v.) and 500 and 750 mg orally in a randomized, double-blind, single-dose, four-period crossover study. On each treatment day, each subject received both oral and i.v. formulations, one of which was a placebo. Blood and urine samples were obtained through 24 h postdose. By each dosing route, the pharmacokinetic profiles were dose proportional. The 400-mg i.v. dose was equivalent to the 500-mg oral dose with respect to the area under the concentration-time curve and was equivalent to the 750-mg oral dose with respect to the maximum concentration of ciprofloxacin in serum. The oral bioavailability was 78.0%. The steady-state volume of distribution averaged 178 liters, and the terminal half-life in serum after i.v. dosing was approximately 4.3 h. Renal clearance accounted for approximately 60% of total body clearance. No significant adverse events were associated with either route of administration.

Administration, Oral

Comparative serum bactericidal activity of ceftizoxime/metronidazole, ceftizoxime, clindamycin, and imipenem against obligate anaerobic bacteria.

We compared the bactericidal activity of serum obtained from healthy volunteers after single intravenous infusions of the combination of ceftizoxime (1 g) plus metronidazole (1 g) and after infusions of ceftizoxime (2 g), clindamycin (900 mg), and imipenem (1 g) against six obligate anaerobes. All agents were bactericidal but only the combination regimen resulted in bactericidal titres greater than 1:2 at 12 h for all the Bacteroides fragilis group organisms. High titres against Fusobacterium necrophorum and anaerobic Gram-positive cocci were attained with ceftizoxime/metronidazole, ceftizoxime, and imipenem 12 h after the dose. Imipenem and the combination of ceftizoxime/metronidazole had the greatest area under the bactericidal curve (AUBC) against the Bacteroides species. Clindamycin had a significantly smaller AUBC than other regimens for all strains tested except B. thetaiotaomicron. Clinical trials are needed to assess the efficacy and cost-benefit ratio of a 12 h dosing regimen of ceftizoxime in combination with metronidazole for treating mixed aerobic/anaerobic infections.

Adult

Comparative in vitro activities of a new quinolone, WIN 57273, and piperacillin plus tazobactam against anaerobic bacteria.

The in vitro activities of a new quinolone, WIN 57273, and the combination of piperacillin and tazobactam, a beta-lactamase inhibitor, were compared with those of cefoxitin, ceftizoxime, chloramphenicol, clindamycin, imipenem, metronidazole, and piperacillin for 123 clinical anaerobic isolates. Ceftizoxime and cefoxitin had equivalent activities, while metronidazole was active against gram-negative isolates. In the Bacteroides fragilis group, species other than B. fragilis were the most resistant. The combination of piperacillin with tazobactam in a ratio of 8 to 1 was more effective than piperacillin against B. fragilis group organisms when the MIC of piperacillin was greater than or equal to 64 micrograms/ml. Overall, WIN 57273 (i) and imipenem (ii) were the most active agents, with MICs for 50 and 90% of strains of (i) 0.25 and 0.5 and (ii) 0.125 and 2 microgram/ml, respectively.

4-Quinolones

Cat-scratch disease in a patient with AIDS.

A case of cat-scratch disease (CSD) in a patient with acquired immunodeficiency syndrome (AIDS) is reported. The lymph node pathologic characteristics were altered from those usually seen with CSD, showing clusters of vacuolated macrophages admixed with pycnotic nuclear debris instead of the usual suppurative granulomas. Evidence for the diagnosis was provided by Warthin-Starry stain and electron microscopic demonstration of the presumed CSD bacillus. Empiric treatment with antibiotics brought about clinical improvement. This case demonstrates the altered lymph node pathologic characteristics with CSD that may occur in a patient with AIDS.

Acquired Immunodeficiency Syndrome

A multicenter comparative study of cefotetan once daily and cefoxitin thrice daily for the treatment of infections of the skin and superficial soft tissue.

To compare the effectiveness of cefotetan administered at 2 g once a day with cefoxitin at 1 or 2 g three times a day in the treatment of hospitalized patients with skin and superficial soft tissue infections, 194 patients from eight centers were enrolled in an open, randomized trial. Most of the 104 evaluable patients in the cefotetan group and 50 in the cefoxitin group were young men with community-acquired, moderate or severe cellulitis, or abscesses of the upper and lower extremities caused by Staphylococcus aureus, Streptococcus species, Escherichia coli, Proteus mirabilis, Bacteroides fragilis and other species of bacteroides, peptococcus species, and peptostreptococcus species. The mean duration of treatment was 7.5 days for cefotetan and 7.1 days for cefoxitin. A successful clinical response was achieved in 97 percent of the cefotetan patients and in 94 percent of the cefoxitin patients. Of the 88 and 39 bacteriologically evaluable patients in the cefotetan and cefoxitin groups, respectively, a satisfactory bacteriologic response occurred in 96 percent and 87 percent of the patients. No clinically significant changes in clinical laboratory determinations were noted. The incidence of adverse reactions in the cefotetan group (17 percent) was significantly different from that for the cefoxitin group (6 percent) (p less than 0.05); however, the incidence of treatment-related reactions was not significant and the events were mild. Discontinuation of therapy was necessary only in two patients in whom allergic-type reactions developed. A once-daily regimen of cefotetan was as effective as thrice-daily cefoxitin in this study in the treatment of primarily polymicrobial, moderate, or severe infections of the skin and superficial soft tissue.

Abscess

Comparative study of cefotetan and cefoxitin in the treatment of intra-abdominal infections.

One hundred eighty-eight patients were enrolled in a multicenter, randomized clinical trial to compare the safety and effectiveness of 1 to 2 gm cefotetan every 12 hours with those of 1 to 2 gm cefoxitin every 6 hours in patients with intra-abdominal infections. Most of the infections were community acquired, were associated with gastrointestinal tract perforation, and were caused by both anaerobic and aerobic bacteria. The median duration of therapy was 6 days for each group. The clinical response rate for the 95 evaluable patients in the cefotetan group was 98%, and that for the 43 evaluable patients in the cefoxitin group was 95%. Bacteriologically, 97% of the 58 evaluable patients in the cefotetan group and 89% of the 27 evaluable patients in the cefoxitin group had a satisfactory or presumed satisfactory response; two patients in the cefotetan group and three in the cefoxitin group were considered bacteriologic failures. Cefotetan was as effective as cefoxitin in eradicating Bacteroides fragilis and other species of Bacteroides, Clostridium sp., and gram-negative bacilli. The incidence of treatment-related adverse reactions for cefotetan (27%) was not statistically different from that for cefoxitin (17%). No clinically significant differences were detected between the treatment groups in changes in the results of clinical laboratory tests performed before and after treatment; a decrease in hematocrit among the cefotetan group was statistically greater (p = 0.04) than that for the cefoxitin group, and a decrease in serum creatinine level for the cefoxitin group was greater than that for the cefotetan group (p = 0.02). Cefotetan may represent an effective, safe, and cost-saving alternative to cefoxitin for the prompt treatment of community-acquired intra-abdominal infections.

Abdomen

Rapid detection of cytomegalovirus by fluorescent monoclonal antibody staining and in situ DNA hybridization in a dram vial cell culture system.

By using dram vial cell culture methods, three commercially available tests for cytomegalovirus (CMV) detection were compared: direct fluorescent monoclonal antibody staining for CMV-specific early and late antigens (direct FA), indirect fluorescent monoclonal antibody staining for a CMV-specific early antigen (indirect FA), and in situ DNA hybridization with a biotinylated CMV-specific DNA probe kit (DNA probe). Of those tests, only the indirect FA provided consistent, reliable virus detection within the initial 24 h postinfection for serial 10-fold dilutions of CMV AD169 (laboratory strain) and for three selected urine samples. However, when used prospectively, the indirect FA failed to detect virus within the initial 10 days postinfection in 15 of 78 consecutive specimens that were eventually positive by cell culture. Although the indirect FA was more sensitive than the direct FA or DNA probe, its utility appeared limited to specimens with high CMV concentrations. On the basis of these data, we recommend that indirect FA be reserved as an adjunct to standard cell culture for selected samples in diagnostic hospital laboratories.

Antibodies, Monoclonal

Effect of peritoneal dialysis fluid and pH on bactericidal activity of ciprofloxacin.

Ciprofloxacin is active in vitro against most bacteria that cause peritonitis associated with peritoneal dialysis. We compared the effects of pH (5.5 and 7.4) and medium (dialysis fluid) on the bactericidal activity of ciprofloxacin, tobramycin, vancomycin plus rifampin, and rifampin against Pseudomonas aeruginosa, Escherichia coli, and three strains of staphylococci. The bactericidal activity of ciprofloxacin was not significantly affected by pH or medium, in contrast to the activity of tobramycin, which was decreased by low pH.

Anti-Bacterial Agents

Lung abscess due to Corynebacterium equi. Report of the first case in a patient with acquired immune deficiency syndrome.

A lung abscess and persistent bacteremia due to Corynebacterium equi are described in a bisexual man with the acquired immune deficiency syndrome (AIDS). Eleven of the 12 previously reported cases have occurred in immunocompromised humans. The occurrence of this infection in a patient with AIDS has not been previously described. Development of resistance to beta-lactam antibiotics was noted following initial therapy. Because this organism resembles nonpathogenic organisms, it may easily be overlooked despite its ability to cause serious infection and persist even with aggressive antimicrobial and surgical therapy.

Acquired Immunodeficiency Syndrome

Clindamycin phosphate kinetics in subjects undergoing CAPD.

The kinetics of intraperitoneally administered clindamycin phosphate were studied in 9 volunteer subjects undergoing CAPD. Volunteers were assigned to 2 groups with the first group receiving clindamycin phosphate 300 mg/l in exchanges 1 through 5, and the second group receiving clindamycin phosphate 300 mg/l in exchange 1, and then 30 mg/l in exchanges 2 through 5. Clindamycin serum and dialysate effluent levels were determined by bioassay. When admixed with dialysate fluid and instilled into the peritoneal cavity, clindamycin phosphate is rapidly activated. Serum concentrations of clindamycin were rapidly achieved in both groups during the first exchange. Subjects in groups I and II had peak serum levels of active drug within 3 (3.94 ug/ml) and 5 (7.35 ug/ml) h, respectively. These results support the practice of not only administering intraperitoneal clindamycin phosphate to treat CAPD-related peritonitis, but using this route of administration to treat systemic infections due to susceptible bacteria in patients without intravenous access.

Adult

The use of an antibiotic order form for antibiotic utilization review: influence on physicians' prescribing patterns.

An antibiotic order form was implemented for all inpatient antibiotic orders at an 800-bed hospital in April 1981 to provide an ongoing, concurrent audit of antibiotic use. The prescribing physician provided the clinical indication for the antibiotic order, and individual patient treatment courses were identified. During the 25-month study period, cephalosporins, penicillin plus ampicillin, and aminoglycosides accounted for 44%, 22%, and 17% of all treatment courses, respectively. Sixty-nine percent of first-generation cephalosporin treatment courses were for prophylaxis, whereas the remaining antibiotics were used for either empirical therapy or documented infection in 56%-79% of cases. After the introduction of the antibiotic order form, there was a significant decline in both the number of antibiotic treatment courses (P = .025) and the percentage of patients receiving any antibiotic (P = .007). We conclude that a specialized antibiotic order form is an effective method for antibiotic utilization review and can have a significant impact on a physician's prescribing patterns.

Anti-Bacterial Agents

Multidrug-resistant Serratia marcescens bacteriuria related to urologic instrumentation.

An outbreak of urinary tract infections caused by multidrug-resistant Serratia marcescens lasted for 12 months and was found to be related to urologic instrumentation. Thirty-four patients had primary infections; four had cross-infections. Only six patients had indwelling bladder catheters. The median interval between instrumentation and initial isolation of Serratia was six days. Seventy-three percent of patients were symptomatic, two were bacteremic. No common instruments, personnel, or wards were identified, and environmental cultures failed to reveal the epidemic strain of Serratia. The outbreak ended when the instrument disinfectant was changed. Serotyping was identical in nine of ten isolates. Intraspecies conjugation demonstrated resistance transfer of gentamicin, tobramycin, carbenicillin, chloramphenicol, and co-trimoxazole. The enzyme 6'-N-acetyl transferase was responsible for gentamicin-inactivation in patient isolates and a transconjugate. Although no significant spread of this multidrug-resistance plasmid to other Enterobacteriaceae occurred in the hospital, two instances of apparent in vivo transfer to other bladder organisms occurred.

Adult

Liquid chromatographic assay of ceftizoxime in sera of normal and uremic patients.

The application of high-pressure liquid chromatography assays for cephalosporin serum concentrations is difficult in uremic patients because of interference from nondialyzable substances. We developed a high-pressure liquid chromatography method for determining the serum concentration of ceftizoxime in normal and uremic patients. The method involves protein precipitation with acetonitrile, followed by removal of the acetonitrile with dichloromethane. Separation was accomplished with a reverse-phase (C-18) column and a mobile phase of 13% acetonitrile and 2.8% acetic acid. UV detection at 310 nm was used to monitor the peaks. This assay produced a linear relationship between peak height ratio and ceftizoxime concentration from 1.5 to 100 micrograms/ml. Samples from 30 patients were assayed by this method and by a bioassay, with a good correlation of results (r = 0.9832). The method was applicable equally to normal and uremic serum samples.

Cefotaxime