Evaluation of ultraviolet light for disinfection of hospital water contaminated with Legionella.

An epidemic of nosocomial Legionella micdadei pneumonia occurred among renal transplant patients in the University of Virginia hospital between 1978 and 1982. Although no further cases were diagnosed after 1982, filters and ultraviolet light (UVL) fittings were installed in 1985 as an attempt to disinfect water piped to rooms of transplant patients, because of concern about persistence of L micdadei in hospital water. Water samples were obtained from eight UVL-treated rooms and eight control rooms. 26 of 95 control samples were culture positive for L micdadei compared with 0 of 71 samples of filtered, UVL-treated water (p less than 0.0001, Fisher's exact test). After the UVL fitting and filter had been bypassed because of a leak, 9 of 33 samples from the UVL rooms were positive (p less than 0.0001). These data suggest that UVL treatment may be useful in continuous disinfection of water in the hospital rooms of high-risk patients.

Comparison of cyclacillin and amoxicillin for therapy for acute maxillary sinusitis.

Cyclacillin, a new aminosalicylic semisynthetic penicillin, was compared with amoxicillin for the therapy of acute bacterial maxillary sinusitis in 80 patients (ages, 12 to 70 years) in a prospective, double-blind, randomized clinical trial. Direct sinus aspirations for quantitative culture were done for all patients before and after 10 days of therapy. Both drugs were administered at a dosage of 500 mg orally three times daily. Among culture-positive patients, clinical cure was achieved in 23 of 26 patients and 25 of 27 patients treated with cyclacillin and amoxicillin, respectively, for an overall cure rate of 91%. Bacteriologic failure occurred in 9% (4 of 44 patients); 3 of the 4 failures were in the cyclacillin group. There was no correlation between clinical or bacteriologic cure and the results of sinus transillumination (clear, dark) at follow-up. Initial direct sinus aspirates were positive in 57 of 80 cases (70%): 25 (44%) of these were the result of Streptococcus pneumoniae and 23 (40%) were the result of Haemophilus influenzae. All of these isolates were susceptible (MIC, less than or equal to 0.5 microgram/ml) to both study drugs; no ampicillin-resistant H. influenzae was recovered. On day 10 of therapy, mean concentrations of both drugs in serum were 2.5 to 2.7 micrograms/ml, but no antibiotic was detectable in 20 of 21 simultaneous sinus aspirates. Adverse effects (rash, diarrhea) were infrequent and similar in both groups. Cyclacillin appears equivalent to amoxicillin in the therapy of acute maxillary sinusitis.

Comparative evaluation of aztreonam in therapy for experimental bacterial meningitis and cerebritis.

Aztreonam (SQ 26,776), a new monocyclic beta-lactam agent, was compared with several frequently used antibiotics in therapy for three types of experimental meningitis in rabbits and for experimental Escherichia coli cerebritis in rats. Aztreonam was highly active against common gram-negative meningeal pathogens in vitro (all minimal bactericidal concentrations less than or equal to 0.125 microgram/ml), including ampicillin-sensitive and ampicillin-resistant strains of Haemophilus influenzae, E. coli, and meningococci. In both rabbits and rats, serum concentrations of all antibiotics evaluated closely approximated concentrations found in humans receiving standard parenteral regimens. The percent penetration of aztreonam into purulent rabbit cerebrospinal fluid was 23%. In experimental meningitis, aztreonam was more rapidly bactericidal than ampicillin in meningitis due to ampicillin-sensitive H. influenzae, than ampicillin or chloramphenicol in meningitis due to ampicillin-resistant H. influenzae, and than gentamicin in meningitis due to E. coli. Aztreonam also reduced concentrations of E. coli in rat brain as rapidly as did gentamicin during therapy for experimental cerebritis, the early stage of brain abscess formation.

Comparison of ciprofloxacin with azlocillin plus tobramycin in the therapy of experimental Pseudomonas aeruginosa endocarditis.

The efficacy of ciprofloxacin (Bay o 9867), a promising new quinolone, was compared with the efficacy of azlocillin plus tobramycin in rabbits with experimentally induced Pseudomonas aeruginosa endocarditis. The MBCs of ciprofloxacin, azlocillin, and tobramycin against the test strain were 0.5, 8, and 4 micrograms/ml respectively. Ciprofloxacin at a concentration of 50 mg/kg or azlocillin at a concentration of 200 mg/kg in combination with tobramycin at a concentration of 5 mg/kg was administered intramuscularly at 8-h intervals for 4 days. Both regimens produced median peak serum bactericidal titers of 1:8. The concentrations of ciprofloxacin, azlocillin, and tobramycin in serum, 1.8 +/- 0.7, 154 +/- 48, and 9.1 +/- 2.4 micrograms/ml (mean +/- standard deviation), respectively, closely approximated concentrations found in humans after accepted dosages. At the end of treatment, the titers of P. aeruginosa were 3.0 +/- 1.6 log10 CFU/g of vegetation (mean +/- standard deviation) for recipients of ciprofloxacin and 3.2 +/- 1.3 log10 CFU/g of vegetation for recipients of azlocillin plus tobramycin. These values compared with control titers of 7.3 +/- 1.6 CFU/g. These data indicate that at the doses used, ciprofloxacin was as effective as azlocillin plus tobramycin in the treatment of P. aeruginosa endocarditis in rabbits. Since the latter drug combination has proven efficacy, ciprofloxacin deserves further evaluation in the therapy of systemic infections in animal models and in humans.

Evaluation of aztreonam in experimental bacterial meningitis and cerebritis.

Aztreonam (SQ 26,776), a new monocyclic beta-lactam agent, was compared with ampicillin, ampicillin plus chloramphenicol, and gentamicin in rabbits with experimental meningitis induced by, respectively, ampicillin-susceptible Haemophilus influenzae, ampicillin-resistant H. influenzae, and Escherichia coli. Aztreonam was also compared with gentamicin in experimentally induced E. coli cerebritis in rats. Doses of the various agents were delivered that produced near-peak concentrations in serum comparable to those attained in humans on standard parenteral regimens. The percent penetration [( concentration in cerebrospinal fluid/concentration in serum] X 100) of aztreonam into purulent rabbit cerebrospinal fluid was 23% (versus 12, 27, and 21%, respectively, for ampicillin, chloramphenicol, and gentamicin). In experimental meningitis in vivo, aztreonam was more rapidly bactericidal than was ampicillin in ampicillin-susceptible H. influenzae meningitis, ampicillin or chloramphenicol in ampicillin-resistant H. influenzae meningitis, or gentamicin in E. coli meningitis. In the therapy of experimental cerebritis, the early stage of brain abscess formation, aztreonam reduced the numbers of E. coli in rat brain as rapidly as did gentamicin. Aztreonam deserves further evaluation in acute gram-negative bacterial infections of the central nervous system in both experimental animals and in humans.