Chemioterapia : international journal of the Mediterranean Society of Chemotherapy最新文献

The in vitro activity of pefloxacin, a new fluoroquinolone, was compared with that of 5 other quinolone compounds (nalidixic and pipemidic acids, norfloxacin, ciprofloxacin, and ofloxacin) against 416 strains of Proteae spp. isolated from urine specimens of hospitalized patients with acute urinary tract infections (UTI). Ciprofloxacin was the most active agent. Norfloxacin, ofloxacin, and pefloxacin were similarly active against Proteus strains (MIC90 = 0.39 microgram/ml). Against Providencia spp. pefloxacin and norfloxacin showed similar activity (MIC90 = 3.12 micrograms/ml). There is minimal discrepancy between minimum inhibitory concentrations and minimum bactericidal concentrations exhibited by the quinolones for all urinary tract pathogens tested. Our in vitro studies indicate that pefloxacin is an active antimicrobial agent and suggest that it will prove useful in the treatment of complicated urinary tract infections due to nalidixic acid-resistant Proteae spp.

The antibacterial activity of usnic acid, the most widely distributed antibiotic among the numerous ones produced by many lichen species has been re-examined and particular attention has been devoted to the activity of optically active forms of usnic acid against Streptococcus mutans. The D(+) enantiomer was found to be more active than the L(+) form and was observed to exert a rather selective activity against S. mutans. Trials carried out in volunteers showed that mouth-rinse with D(+) usnic acid preparations exerted a selective and long lasting action against S. mutans, without substantially altering the equilibrium of normal oral bacterial flora. The adherence of S. mutans to smooth surfaces is not increased by the presence of subinhibiting concentrations of D(+) usnic acid. This is at variance with what has been observed with other antibiotics. These characteristics make D(+) usnic acid a suitable candidate for topical use in oral medicine.

Periodontally affected sites may show resistance to mechanical therapy associated with conventional treatment. This periodontal situation is the result of the cooperation of bacteria, and in some cases the development of superinfections due to opportunistic bacteria is possible. These situations need particular attention in the choice of antibiotics. From some sites, bacteria not commonly found as periodontal pathogens may be isolated; they are generally resistant to antibiotics administered in periodontal therapy. Attention should be used particularly in cases where lesions most resemble those characteristic of the action of gram-negative bacteria. According to results of the present research these cases should be managed with antibiotic combinations and conventional mechanical therapy.

Nalidixic acid and two recently synthetized 4-quinolones eliminated F'lac and R-plasmids from E. coli at concentrations of one half or one quarter of the minimum inhibitory concentration (MIC). Two of the three plasmids tested were cured by all derivatives, although with different frequencies. Pefloxacin was the most effective compound compared with the other quinolones and nalidixic acid the least active.

7432-S (SCH 39720) was the most active beta-lactam tested against the Enterobacteriaceae, inhibiting 92% of strains at less than or equal to 8.0 micrograms/ml compared to 82%, 65% and 39% of strains inhibited by cefixime, cefuroxime and cefaclor, respectively. 7432-S was also very effective against Haemophilus influenzae (MIC90, less than or equal to 0.25 microgram/ml), Branhamella catarrhalis (MIC90, 4.0 micrograms/ml) and Neisseria meningitidis (MIC90, less than or equal to 0.25 microgram/ml). Serogroup B streptococci and the penicillin-resistant pneumococci were generally less susceptible to 7432-S and comparison cephems than Streptococcus pyogenes or penicillin-susceptible S. pneumoniae isolates. Pseudomonas spp., enterococci, Acinetobacter spp. and Staphylococcus spp. were routinely resistant to 7432-S (MIC50s, greater than or equal to 32 micrograms/ml).

The aqueous humor penetration of the third-generation cephalosporin, ceftizoxime, was determined in 21 patients awaiting cataract extraction, after an intravenous bolus injection of 2 g. The beta-lactam compound achieved a mean peak aqueous humor concentration of 7.8 mg/l two hours after administration with a serum/humor percent ratio ranging between 7 and 16% during the four-hour sampling interval. Therefore, ceftizoxime levels in this extravascular fluid were above the minimum inhibitory concentrations for the majority of sensitive organisms.

Thirty patients with advanced breast cancer, not pretreated with chemotherapy, received a polychemotherapy regimen containing mitoxantrone, fluorouracil and cyclophosphamide at the dose of 10 mg/m2, 500 mg/m2 and 500 mg/m2 i.v. respectively every 28 days. Out of 25 patients evaluable for response 9 patients achieved a partial remission (36%) for a median duration of 20.5 weeks. The main side effects were leukopenia (grade 3-4 in 70%) and nausea-vomiting (grade 3-4 in 27%). Alopecia was present only in 5 patients (17%). Three patients demonstrated instrumental signs of cardiotoxicity without clinical symptoms.

Pefloxacin, a new piperazinyl substituted quinolone derivative, reduced at sub-MICs (Minimal Subinhibitory Concentrations: four times lower than Minimal Inhibitory Concentrations) the in vitro adherence of Proteus-Providencia spp. to squamous epithelial cells obtained from the urinary tract. The decrease of adherence was about 30% and 50% after 1 h and, respectively, 16-18 h of incubation with pefloxacin. This finding suggests that pefloxacin may play a role in determining the in vivo adhesion of Proteus-Providencia spp. on the urinary tract and consequently the expression of bacterial pathogenic potency.

The authors carried out a study to assess the efficacy of an antibiotic treatment (cefotetan or cefoxitin) in 22 stratified patients with biliary sepsis, at low and high risk. The severity of sepsis was assessed by a biliary sepsis score (B.S.S.). No significant difference in results was observed between the two treatments in low-risk groups (cefotetan 80%, cefoxitin 75% satisfactory), while the difference between the high risk groups was significant (cefotetan 75%, cefoxitin 40% satisfactory). In the low risk group it can be stated that better nutritional and immunological status provide adequate host defences and that the antibiotic treatment is less important in determining surgical outcome. In high risk patients the efficacy of an antibiotic, cefotetan in this case, can significantly improve clinical results.

Data on the antibacterial activity of cefotetan collected since 1985 have been compiled into a computer database and an analysis of results on more than 100,000 clinical isolates presented. The studies were conducted in 285 hospitals located throughout Europe, South Africa, Australia and the USA. The results demonstrate the effectiveness of cefotetan as a broad spectrum agent with significant activity against clinically important aerobes and anaerobes. This is exemplified by the susceptibility to cefotetan of 92% of 14,315 strains of Staphylococcus aureus, 99% of 24,103 strains of Escherichia coli and 93% of 1,841 strains of Bacteroides fragilis.