Biomedical subjects
Publications and source records attributed to B E Scully.
Intravenous therapy for a variety of infections can be performed in the home setting; the therapy is safe and relatively cost effective. Close monitoring of the patient to ensure good care is essential. In the coming years, the variety of infections treatable at home will increase.
The effectiveness and safety of mupirocin calcium ointment applied to the anterior part of the nares for 5 days in the eradication of nasal carriage of Staphylococcus aureus was investigated in a placebo-controlled, double-blind study. Subjects were healthy medical center staff who had two positive cultures of the anterior nares for S aureus. Antimicrobial susceptibility, phage typing, and restriction endonuclease analysis of plasmid DNA were used to monitor the identity of relapsing and persisting strains. Mupirocin eliminated 74% of S aureus at early follow-up and 91% of original strains. At 4 weeks, 78% of the original strains were eradicated, whereas all of the placebo group remained colonized. Recolonization with mupirocin-resistant strains occurred in six patients, but these were of different phage and plasmid types from the original isolates. None of the subjects had serious adverse effects. Applied intranasally for 5 days, a calcium preparation of mupirocin in a paraffin base is effective in eliminating S aureus nasal carriage and is well tolerated.
The serum bactericidal activity of clarithromycin in six normal human volunteers was determined after oral doses of 500 mg. The mean plasma levels of clarithromycin plus 14-hydroxy clarithromycin were 2.11 micrograms/mL after the second dose and 4.36 micrograms/mL after the sixth dose. The mean serum bactericidal titer against Haemophilus influenzae after the second dose was 1:8 and after the sixth dose 1:16 when unheated serum was used. Similar values were obtained when serum to which clarithromycin and 14-hydroxy clarithromycin was added was tested. Mean serum bactericidal titers against H. influenzae determined in Haemophilus test broth or heated serum were 1:2 and 1:4, respectively. Against Streptococcus pneumoniae and Streptococcus pyogenes, there was greater than 1:16 serum bactericidal levels at 12 hours after the sixth dose of clarithromycin.
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Metronidazole is a highly effective therapy for anaerobic infections and a variety of protozoal and parasitic diseases. Its pharmacokinetics, toxicities, and unique mode of action are reviewed in detail. Indications for use and respective dosages are suggested.
Diagnosing the acquired immunodeficiency syndrome (AIDS) in transplant recipients can be difficult due to the patient's medication-induced immunosuppressed state. We report two renal allograft recipients who acquired HIV infection at the time of transplantation and later went on to develop multiple opportunistic infections. Careful documentation of HIV antibody status of the donor and recipient, when available, the nature of immunosuppressive therapy used, the type of infections and their timing after transplantation, as well as the patient's absolute T4 lymphocyte count, T cell ratio, and B cell humoral response to infection were used as factors to distinguish between infection related to immunosuppressive therapy and that seen in HIV-induced immunodeficiency. Reduction in immunosuppressive therapy because of the HIV-related immunodeficiency state did not result in allograft rejection. Both patients died of their multiple infections. The determination of AIDS in the transplant recipient has both therapeutic and prognostic significance. This diagnosis should be considered when transplant patients develop unusual infections in relationship to their posttransplant course.
There is great need for an oral agent that could be used to treat pulmonary exacerbations in patients with cystic fibrosis. In this study, the use of oral ciprofloxacin as sole therapy was evaluated in 18 patients with 39 infectious episodes; 13 episodes were classified as severe, 19 were classified as moderate, and seven were classified as mild. Patients ranged in age from eight to 36 years (mean, 23 years). Dosage varied according to severity of disease, body size, and the susceptibility of the Pseudomonas isolate to ciprofloxacin; the dose ranged from 750 to 2,250 mg daily (mean, 1,800 mg). Ten patients received one course of ciprofloxacin, and eight received repeated courses. The overall clinical response rate was 82 percent. There was a response to the initial treatment course in 96 percent of the patients. Those in whom therapy failed had been re-treated with ciprofloxacin and were severely ill. Failure to respond correlated poorly with pretreatment minimal inhibitory concentration (MIC) values (0.6 microgram/ml for failures versus 0.4 microgram/ml for responses). Pseudomonas could not be eradicated from the sputum of any of the patients, although there was a marked reduction in purulence and bacterial counts. In general, patients who did not require re-treatment for three months would again have susceptible organisms. When organisms became resistant to ciprofloxacin (MIC greater than 2 micrograms/ml), they showed no concomitant new aminoglycoside or beta-lactam resistance. No serious toxicity occurred in any of the 39 episodes of treatment. In seven patients treated with combination therapy (tobramycin or azlocillin), the infecting organisms were reduced in number, but eradication of Pseudomonas generally could not be achieved. Increases in MIC occurred during combination therapy. Ciprofloxacin is a major advance in the treatment of bronchopulmonary infection in patients with cystic fibrosis.
Thirty-four patients were treated with intravenous ciprofloxacin. Thirty infections occurring in 28 patients were assessable for the efficacy analysis. The drug dosage was 300 mg every 12 hours in 19 patients and 200 mg intravenously every 12 hours in nine patients. Twelve patients were also given ciprofloxacin orally after initial intravenous therapy. The mean duration of total therapy was 31 days. The overall clinical response rate was 87 percent, and the bacteriologic response rate was 70 percent. Favorable responses were observed in 10 of 12 patients with osteomyelitis/septic arthritis; seven of eight with soft tissue infection; four of four with pneumonitis; one of two with cystic fibrosis; and four of four with urinary tract infections. Resistance to ciprofloxacin developed in three Pseudomonas aeruginosa isolates. Toxicity was minor: phlebitis occurred in six patients, nausea in six, and rash in one. Intravenously administered ciprofloxacin or intravenous ciprofloxacin followed by oral ciprofloxacin is a safe and effective therapy for serious infections.
Ciprofloxacin is a fluorinated carboxyquinolone that inhibits Enterobacteriaceae, staphylococci, and Pseudomonas at low concentrations. It has poor activity against Bacteroides fragilis. In this study, the effect of administration of ciprofloxacin on bowel flora was determined in patients treated for different infections. Patients, aged 22 to 70 years, were treated with 500 mg of ciprofloxacin every 12 hours or 750 mg every eight hours for seven to 42 days. Some patients had advanced cystic fibrosis; other patients had infections with resistant bacteria. Infecting organisms were Pseudomonas aeruginosa, Staphylococcus aureus, Serratia, and Acinetobacter. Sites of infections were lung, soft tissue, and urinary tract. Stool samples were evaluated initially, during therapy, and after therapy. No resistant gram-negative aerobic species emerged; five patients had yeast colonization, staphylococci were found in three patients, and streptococci were found in one patient. Ciprofloxacin did not select resistant gram-negative bacteria in the stool, although sputum isolates showed increases in minimal inhibitory concentrations. Resistant bacteria were not selected in the fecal flora of patients who had received beta-lactam and aminoglycoside antibiotics before therapy with ciprofloxacin.
The efficacy and safety of oral ciprofloxacin, a fluoroquinolone, were evaluated in the treatment of infection due to Pseudomonas aeruginosa. 96 infections in 71 patients were treated. Substantial underlying disease was present in most of the patients, and 25 (35%) were seriously ill. 52% of pseudomonas isolates were carbenicillin-resistant, and 31% gentamicin-resistant. The overall clinical response rate was 77%-28 of 35 exacerbations of cystic fibrosis respiratory disease, 17 of 19 urinary infections, 4 of 6 osteomyelitis, and 11 of 15 soft tissue infections. The bacteriological cure rate was 34%-0 of 35 cystic fibrosis, 4 of 17 respiratory infections, 17 of 19 urinary infections, 4 of 6 osteomyelitis, and 8 of 15 soft tissue infections. Ps aeruginosa developed resistance to ciprofloxacin in 25 of 96 infections. Side-effects were generally slight with nausea in 14 (15%) the most common, and there were only two substantial superinfections.
Of 125 patients treated with ciprofloxacin at the Columbia-Presbyterian Medical Center, New York, 34 had infections due to bacteria other than Pseudomonas aeruginosa. The mean age of the patients was 50 years (19-88 years) and most had significant underlying disease. There were nine lower respiratory infections, eight urinary tract infections, eight soft tissue infections, three osteomyelitis, and three intra-abdominal infections. The pathogens were: Escherichia coli, 7 (mean MIC 0.07 mg/l); Serratia marcescens, 6 (0.2 mg/l); Enterobacter spp., 5 (0.1 mg/l); Klebsiella pneumoniae, 3 (0.1 mg/l); Proteus mirabilis, 3 (0.06 mg/l); Cutrobacter freundii, 2 (0.06 mg/l), Staphylococcus aureus, 3 (0.5 mg/l); and one each of Acinetobacter anitratus. Haemophilus, influenzae, Salmonella enteritidis, Flavobacterium meningosepticum, and Streptococcus faecalis. Of these organisms 81% were resistant to ampicillin, 70% to carbenicillin, 22% to gentamicin, 49% to cefazolin and cephalexin, and 25% to cotrimoxazole. Ten patients had concomitant Ps. aeruginosa infections. Patients were treated orally with 500 mg or 750 mg ciprofloxacin every 12 h. The overall clinical response rate was 88%, and the bacteriological response 76%, and 65% if Ps. aeruginosa is included. Resistance to ciprofloxacin developed in one Staph. aureus and one Ser. marcescens (MIC greater than 2 mg/l). Toxicity was minor. Ciprofloxacin was effective and safe therapy of infections due to Gram-negative bacteria resistant to many of the currently available oral and parenteral agents.
Serum and urine levels of ticarcillin and clavulanic acid after administration of doses of 50 mg/kg and 1.7 mg/kg or 50 mg/kg and 3 g/0.1 g, respectively, are potentially toxic to susceptible bacteria. Both compounds are widely distributed in body tissues and fluids, with concentrations exceeding the minimal inhibitory concentrations of most pathogens. Excretion is primarily renal, although there is some metabolism of clavulanate in the body. Due to accumulation, dosage adjustment is required for patients with renal insufficiency. Both ticarcillin and clavulanic acid are cleared by hemodialysis.
Clavulanic acid is a potent inhibitor of bacterial beta-lactamases, and ticarcillin is a potent antipseudomonal penicillin. The combination of ticarcillin disodium and clavulanate potassium provides an excellent spectrum of activity against the majority of bacterial pathogens responsible for serious infections in both normal and abnormal hosts. Eighteen courses of therapy were administered to 16 patients; 35 percent of the patients were in poor or critical condition, and all but one had severe underlying disease. Thirteen separate episodes of pneumonia were treated, of which nine were in patients with cystic fibrosis, and 11 involved Pseudomonas aeruginosa. Of the 13 cases of pneumonia, 11 showed clinical cure or improvement, whereas only three showed bacteriologic cure. Of the four nonpulmonary cases, three showed clinical improvement or cure, and one showed a bacteriologic cure. In two patients, phlebitis developed at the site of intravenous infusion. The combination of ticarcillin and clavulanic acid is safe and effective therapy for pneumonia in anatomically compromised hosts.
Ciprofloxacin is an investigational quinolone agent possessing an impressive antibacterial spectrum. Its pharmacokinetics were studied in six volunteers after 250-mg and 500-mg single oral doses, and its bactericidal activity compared to that of trimethoprim-sulfamethoxazole given to the same volunteers. Mean peak serum levels were 1.45 micrograms/mL and 2.46 micrograms/mL for 250-mg and 500-mg doses, and time to peak was 1 and 1.3 hours. The 12-hour levels were 0.12 micrograms and 0.22 microgram. Half-life (T1/2)alpha were 0.32 and 0.43 with T1/2 beta were 3.97 and 4.15 and volume of distribution (area) were 80L and 90L, respectively. Area under the concentration curve (AUC) was 5.65 h X micrograms/mL and 10.37h X micrograms/mL. Serum clearance was 23L for both doses. Approximately 49% of the 250-mg dose and 43% of the 500-mg dose was recovered in the urine. Bactericidal levels were determined against clinical isolates. Sera at 1.5 hours after the 500-mg dose averaged bactericidal levels of 1:20 or better for an Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and beta-lactamase producing Haemophilus influenzae and Branhamella catarrhalis. Urinary bactericidal levels at eight to 12 hours were greater than or equal to 1:157 for E coli, K pneumoniae, gentamicin-piperacillin resistant P aeruginosa, Staphylococcus aureus, and 1:20 for Streptococcus faecalis. Serum bactericidal levels were superior, and urine bactericidal levels were superior or equal to the bactericidal levels obtained with trimethoprim-sulfamethoxazole.(ABSTRACT TRUNCATED AT 250 WORDS)
Aztreonam is a novel antimicrobial agent belonging to the monobactam class of antibiotics. It inhibits both beta-lactamase-producing and non-beta-lactamase-producing aerobic gram-negative bacilli, but it has no activity against gram-positive species or against anaerobic species. The efficacy of aztreonam in the treatment of infection in 76 patients and its safety in 87 patients was evaluated. The majority (91 percent) of patients had significant underlying disease, and 47 percent were critically ill. Aztreonam produced an overall clinical response of 86 percent, with 10 of 11 cases of bacteremia cured, including four due to Pseudomonas aeruginosa, seven of eight cases of pneumonia, and seven of nine episodes of osteomyelitis. Infections due to bacteria resistant to ampicillin, carbenicillin, cefazolin, cefamandole, cefoxitin, and gentamicin were cured. Although 15 of 18 patients with exacerbations of pulmonary infection due to P. aeruginosa showed clinical improvement, bacteriologic cure was not achieved, as has been noted with other drugs. Similarly, patients with major underlying structural abnormalities of the urinary tract showed early relapses of bacteriuria. Aztreonam combined with antistaphylococcal, antistreptococcal, or antianaerobic agents provided an alternative to aminoglycoside use in these non-neutropenic patients. Administration of 1 or 2 g every eight hours yield serum bactericidal levels well in excess of 1:8 against all Enterobacteriaceae and some P. aeruginosa strains. There was a low incidence of adverse side effects, none serious. Overall, aztreonam is a useful alternative to the drugs available for use in hospital-acquired gram-negative infections and provides a chance for more directed therapy.
The pharmacokinetics of cefixime (FK 027), a broad-spectrum cephalosporin, were assessed in 12 normal subjects after single oral doses of 50, 100, 200, and 400 mg. Mean peak serum concentrations were 1.02, 1.46, 2.63, and 3.85 micrograms/ml after the four respective doses. Respective mean serum levels at 12 hours were 0.16, 0.33, 0.72, and 1.13 micrograms/ml. Volumes of distribution averaged 0.1 L/kg body weight, and the elimination t1/2 was 3 hours for all doses. The AUC was 7.01, 11.4, 22.5, and 36.4 micrograms X hr/ml for the four doses, respectively. Serum clearance averaged 0.4 mg/min/kg and mean 24-hour urinary recovery was 21%, 19%, 20%, and 16% for the four respective doses. Serum bactericidal titers at 4 hours exceeded 1:16 for Streptococcus pneumoniae, S. pyogenes, Hemophilus influenzae, and Branhamella catarrhalis. Urine bactericidal titers exceeded 1:8 for Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae resistant to the available oral cephalosporins.
Ciprofloxacin pharmacokinetics were studied in 6 volunteers after 250 and 500 mg single oral doses. Mean peak serum levels were 1.45 micrograms/ml and 2.5 micrograms/ml for 250 and 500 mg doses. The 12-h levels were 0.12 micrograms and 0.22 micrograms. T1/2 alpha values were 0.32 and 0.43 h; T1/2 beta was 4 h and Vd (area) values were 80L and 90L for the two doses respectively. AUC was 5.65 h. micrograms/ml and 10.37 h. micrograms/ml. Serum clearance was 23L for both doses. Approximately 49% of the 250 mg dose and 43% of the 500 mg dose was recovered in the urine. Ciprofloxacin's in vitro activity and human pharmacology should permit a twice or once-daily dosing schedule for systemic infections due to most Enterobacteriaceae, Haemophilus, Branhamella and Pseudomonas and S. aureus, and once-daily doses for urinary and gastrointestinal infections.
The clinical efficacy and safety of ceftriaxone when administered twice daily was evaluated in the treatment of serious infections, including 9 episodes of bacteremia, 4 of pneumonia, 7 of intra-abdominal or soft tissue infections, 11 of urinary tract infections, 3 of osteomyelitis, and 5 of meningitis. Causative pathogens were Strep. pneumoniae, other hemolytic streptococci, E. coli, P. mirabilis, K. pneumoniae, and species of Enterobacter, Serratia, and Pseudomonas. The overall clinical cure rate was 87 percent and the bacteriologic cure rate was 77 percent. Cures were achieved in infections due to organisms resistant to ampicillin, cefazolin, cefamandole, carbenicillin, and gentamicin. Peak plasma levels were far in excess of the minimal inhibitory concentrations of Enterobacteriaceae. Adverse effects were infrequent, and in only one instance was it necessary to discontinue treatment. Resistance to ceftriaxone developed during therapy with several Enterobacter and Pseudomonas species isolates. Ceftriaxone appears to be a useful agent for treatment of serious gram-negative infections in seriously ill patients.