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A randomized trial of high-dose ciprofloxacin versus azlocillin and netilmicin in the empirical therapy of febrile neutropenic patients.

A prospective, randomized trial comparing monotherapy with high-dose ciprofloxacin versus a standard combination regimen of azlocillin and netilmicin in the empirical treatment of febrile episodes in neutropenic patients was performed. One hundred and forty-six patient episodes were randomized, but ten (seven ciprofloxacin and three azlocillin/netilmicin) were considered unevaluable for efficacy, and three episodes were withdrawn due to incorrect randomization or non-neutropenia. Of the remaining 133 episodes, infections resolved without modification of therapy in 25/66 (38%) versus 28/67 (42%) of ciprofloxacin and azlocillin/netilmicin treated groups respectively (P = 0.72). Considering all randomized episodes, therapy was modified in 46/73 (63%) episodes with ciprofloxacin and 39/70 (56%) with azlocillin/netilmicin (P = 0.40). Of 73 patient episodes randomized to ciprofloxacin, 25 (34%) received oral follow-on therapy after a median of three days of intravenous therapy. Infections were microbiologically documented in 31/73 (42%) ciprofloxacin and 32/70 (46%) azlocillin/netilmicin, of which 8/27 (30%) and 14/31 (45%) of evaluable episodes resolved without modification of therapy respectively (P = 0.28). Gram-positive organisms accounted for 78% of all organisms cultured with 36% coagulase-negative staphylococci. Bacteriological eradication was recorded in 18/24 (75%) and 26/29 (90%) evaluable patient episodes treated with ciprofloxacin and azlocillin/netilmicin respectively (P = 0.27). Superinfections were seen in 14% of episodes in both groups, and subsequent infections in 12% ciprofloxacin and 14% azlocillin/netilmicin treated patients. Two patients (one ciprofloxacin and one azlocillin/netilmicin) died within 48 h of randomization, and a further 13 patients (four ciprofloxacin and nine azlocillin/netilmicin) died before resolution of neutropenia. Adverse events were recorded in 9% and 15% of ciprofloxacin and azlocillin/netilmicin treated patients respectively, with skin rash (five ciprofloxacin and four azlocillin/netilmicin), nephrotoxicity (two azlocillin/netilmicin), abnormal liver function tests (two azlocillin/netilmicin), ototoxicity (one azlocillin/netilmicin) and nausea (one ciprofloxacin) being the major events recorded. It was concluded that monotherapy with ciprofloxacin at this dosage is a safe alternative to combination therapy with azlocillin/netilmicin, and has the advantages of twice daily administration, iv and oral presentations, no cross allergy in beta-lactam-hypersensitive patients, and no nephro- or oto-toxicity.

Adolescent

Trimethoprim-sulfamethoxazole compared with ciprofloxacin for the prevention of urinary tract infection in renal transplant recipients. A double-blind, randomized controlled trial.

BACKGROUND: Prophylaxis with low-dose trimethoprim-sulfamethoxazole has been shown to be cost-effective in the prevention of urinary tract infections, pyelonephritis, urosepsis, and pneumocystis pneumonia in renal transplant recipients. Ciprofloxacin, effective against almost all urinary tract pathogens in this patient population, represents a promising alternative prophylactic agent for patients unable to tolerate trimethoprim-sulfamethoxazole due to toxicity. METHODS: We conducted a randomized, double-blind trial to compare low-dose trimethoprim-sulfamethoxazole with ciprofloxacin for the prevention of urinary tract infections in renal transplant recipients. Patients received either ciprofloxacin (250 mg) or trimethoprim-sulfamethoxazole (80 mg trimethoprim, 400 mg sulfamethoxazole) daily for 6 months following transplantation. Treatment was considered successful if patients completed the 6-month course and 3-month follow-up period without evidence of urinary tract infection or drug-related toxicities. RESULTS: Of 103 eligible patients, 51 received ciprofloxacin and 52 received trimethoprim-sulfamethoxazole. At 6 months, treatment was successful in 75% (38 of 51) receiving ciprofloxacin and 71% (37 of 52) treated with trimethoprim-sulfamethoxazole (P = 0.87, relative risk 1.04, 95% confidence limits 0.83 to 1.33). Thirteen patients (25%) receiving trimethoprim-sulfamethoxazole withdrew from the study-4 for resistant urinary tract infection and 9 for drug-related toxicity, while 3 (6%) of the patients receiving ciprofloxacin withdrew because of drug-related toxicity (P = 0.016, relative risk of urinary tract infection or adverse event 0.24, 95% confidence limits 0.07 to 0.78). At 9 months, all 38 patients who completed the 6-month course of ciprofloxacin remained free of urinary tract infection, while an additional 4 patients who had received trimethoprim-sulfamethoxazole prophylaxis (total of 8 patients over the 9 months) developed urinary tract infections (P = 0.006, Fisher's exact test for urinary tract infection alone). Pneumocystis pneumonia occurred in a total of 7 (14%) patients who were randomized to ciprofloxacin, but 2 of the 7 had withdrawn from the study at least 2 weeks prior to the diagnosis of pneumocystis pneumonia. There were no cases of pneumocystis pneumonia in patients receiving trimethoprim-sulfamethoxazole (P = 0.006). Following completion of the study, monthly aerosolized pentamidine administered in conjunction with ciprofloxacin has provided complete protection against urinary tract infection and pneumocystis pneumonia in 30 transplant recipients unable to tolerate trimethoprim-sulfamethoxazole therapy. CONCLUSIONS: Ciprofloxacin is at least as effective as trimethoprim-sulfamethoxazole in the prevention of urinary tract infection in renal transplant recipients, and is better tolerated. Ciprofloxacin prophylaxis is associated with a higher incidence of pneumocystis pneumonia than is trimethoprim-sulfamethoxazole therapy. An uncontrolled follow-up study suggests that ciprofloxacin prophylaxis combined with monthly aerosolized pentamidine may be efficacious in preventing both urinary tract infection and pneumocystis pneumonia in renal transplant recipients.

Adult

Molecular epidemiology of endemic ciprofloxacin-susceptible and -resistant Enterobacteriaceae.

OBJECTIVES: To elucidate the epidemiology of widespread ciprofloxacin resistance in our Veterans Affairs medical center using whole cell DNA analysis. DESIGN: In vitro study of ciprofloxacin resistant and susceptible Enterobacteriaceae isolated during the course of a clinical epidemiologic study of quinolone resistance. SETTING: Veterans Affairs Medical Center with acute care and long-term care divisions. RESULTS: We examined 40 ciprofloxacin-resistant strains of Serratia marcescens, Proteus mirabilis, and Providencia stuartii using restriction endonuclease analysis of whole cell DNA and compared them with concomitantly isolated ciprofloxacin sensitive strains. We sought to determine whether resistant strains were identical to susceptible strains, indicating in vivo emergence of resistant strains from susceptible strains, and whether resistant strains were shared among patients. All 26 ciprofloxacin-resistant S marcescens isolates shared a single ecoRI restriction pattern. Multiple patterns were seen in the ciprofloxacin-susceptible S marcescens isolates; however, several isolates had a pattern matching that of the resistant isolates. Similar results were seen among the P mirabilis isolates. Three different ecoRI patterns were found among the ciprofloxacin-resistant P stuartii isolates; none matched those found among the susceptible isolates. The frequency of spontaneous emergence of ciprofloxacin resistance in susceptible S marcescens strains with restriction pattern matching that of the resistant strains was significantly higher than that of nonmatching strains. CONCLUSIONS: Ciprofloxacin-resistant strains of Enterobacteriaceae became widespread within a short period of time. Resistant strains of S marcescens and P mirabilis arose from endemic susceptible strains. The resistant strain of S marcescens appeared to arise from a susceptible strain with a relatively high frequency of spontaneous ciprofloxacin resistance.

Case-Control Studies

Comparison of three-day temafloxacin with seven-day ciprofloxacin treatment of urinary tract infections in women.

BACKGROUND: Temafloxacin is a new broad-spectrum arylfluoroquinolone antimicrobial with an extended serum half-life. METHODS: In this large, multicenter, double-blind clinical trial, 404 women with acute, uncomplicated urinary tract infections (UTI) were randomized to receive temafloxacin 400 mg once daily for 3 days, or ciprofloxacin 250 mg twice daily for 7 days. Clinical and microbiologic evaluations were repeated at 4 to 5 days after initiation of treatment, at the end of therapy, and at 5 to 9 days posttreatment. One hundred fifteen patients who received temafloxacin and 105 patients who received ciprofloxacin met the eligibility criteria for efficacy evaluation. The predominant urinary pathogens were Escherichia coli, Proteus mirabilis, and coagulase-negative staphylococci. No pretherapy isolate was resistant to either study drug. RESULTS: Bacteriologic eradication was observed in 112 (97%) of 115 women treated with temafloxacin and 101 (96%) of 105 women treated with ciprofloxacin. Clinical cure rates at 5 to 9 days posttreatment were 90% (the remaining 10% improved) with temafloxacin and 95% (the remaining 5% improved) with ciprofloxacin. Adverse effects associated with treatment occurred in 24 (12%) women who received temafloxacin and 31 (15%) women who received ciprofloxacin. Headache (2% with temafloxacin and 2% with ciprofloxacin), nausea (3% with temafloxacin and 6% with ciprofloxacin), and somnolence (4% with temafloxacin and 3% with ciprofloxacin) were reported most often. Only three and five patients who were treated with temafloxacin and ciprofloxacin, respectively, discontinued treatment because of adverse effects. CONCLUSIONS: In this study, a 3-day treatment regimen using a single daily 400-mg dose of temafloxacin was found to be as effective as a 7-day course of ciprofloxacin in women with acute uncomplicated UTI.

Adult

Pharmacokinetics of ciprofloxacin after intraperitoneal administration in uninfected patients undergoing CCPD.

Ciprofloxacin is increasingly used to treat peritoneal dialysis related peritonitis. We studied the pharmacokinetics of intraperitoneally administered ciprofloxacin in six uninfected CCPD patients. In a randomized cross-over setting ciprofloxacin was added either to a long dwell exchange (lastbag) or to four short dwell exchanges (dwell time 1.5 h). Addition of ciprofloxacin (25 mg/l) during the four short dwell exchanges resulted in dialysate levels of 21.1-13.3 mg/l during these exchanges. In the subsequent last bag devoid of ciprofloxacin a dialysate Cmax,D of 1.38 mg/l was observed at 30 min. Mean +/- SD serum Cmax,S was 0.59 +/- 0.29 mg/l after 5.4 h. Instillation of 100 mg/l ciprofloxacin in the last-bag yielded Cmax,D of 99.1 mg/l, falling with a t1/2 of 3.3 h towards levels < 2 mg/l at 19.8 h. A mean +/- SD serum Cmax,S of 0.69 +/- 0.19 was reached after 4 h. During four subsequent 1.5h exchanges without ciprofloxacin dialysate levels were < 0.1 mg/l. Instillation of 25 mg/l ciprofloxacin in the last-bag yielded a Cmax,D of 21.7 mg/l, falling towards levels < 2 mg/l at 15 h with a t1/2 of 3.85 h. A mean +/- SD serum Cmax,S of 0.26 +/- 0.03 was reached after 8 h. We conclude that the rapid absorption of ciprofloxacin from the dialysate into the tissues requires ciprofloxacin to be administered to all CCPD bags to ensure bactericidal dialysate levels. When therapeutic serum levels are required higher intraperitoneal doses or an oral or i.v. loading dose is warranted.

Adult

Prophylactic ciprofloxacin for catheter-associated urinary-tract infection.

Patients receiving antibiotics during bladder drainage have a lower incidence of urinary-tract infections compared with similar patients not on antibiotics. However, antibiotic prophylaxis in patients with a urinary catheter is opposed because of the fear of inducing resistant bacterial strains. We have done a double-blind, placebo-controlled trial of prophylactic ciprofloxacin in selected groups of surgical patients who had postoperative bladder drainage scheduled to last for 3 to 14 days. Patients were randomly assigned to receive placebo (n = 61), 250 mg ciprofloxacin per day (n = 59), or 500 mg ciprofloxacin twice daily (n = 64) from postoperative day 2 until catheter removal. 75% of placebo patients were bacteriuric at catheter removal compared with 16% of ciprofloxacin-treated patients (relative risk [RR] [95% CI] 4.7 [3.0-7.4]). The prevalence of pyuria among placebo patients increased from 11% to 42% while the catheter was in place; by contrast, the rate of pyuria was 11% or less in patients receiving ciprofloxacin (RR 4.0 [2.1-7.3]). 20% of placebo patients had symptomatic urinary-tract infections, including 3 with septicaemia, compared with 5% of the ciprofloxacin groups (RR 4.0 [1.6-10.2]). Bacteria isolated from urines of placebo patients at catheter removal were mostly species of enterobacteriaceae (37%), staphylococci (26%), and Enterococcus faecalis (20%), whereas species isolated from urines of ciprofloxacin patients were virtually all gram-positive. Ciprofloxacin-resistant mutants of normally sensitive gram-negative bacteria were not observed. Ciprofloxacin prophylaxis is effective and safe in the prevention of catheter-associated urinary tract infection and related morbidity in selected groups of patients requiring 3 to 14 days of bladder drainage.

Adult

A comparison of the safety and efficacy of lomefloxacin and ciprofloxacin in the treatment of complicated or recurrent urinary tract infections.

The efficacy and safety of two fluoroquinolone antimicrobial agents, lomefloxacin and ciprofloxacin, were compared in a randomized, investigator-blinded, multiple-dose study that enrolled 150 adult outpatients with complicated or recurrent urinary tract infections. A total of 75 patients were treated with 400 mg of lomefloxacin once daily for 10-14 days; an equal number of patients received 500 mg of ciprofloxacin every 12 hours for 10-14 days. Both groups of patients were comparable in terms of demographics and distribution of underlying conditions. The most frequently occurring pathogens in both groups were Escherichia coli and Klebsiella pneumoniae. A total of 142 patients met the criteria for efficacy evaluation, 72 in the lomefloxacin group and 70 in the ciprofloxacin group. Eradication of the initial pathogen (post-treatment culture of less than or equal to 10(4) colony-forming units (CFU)/mL) was noted in 97.2% of patients treated with lomefloxacin and in 95.7% of ciprofloxacin-treated patients. Clinical success (disappearance or amelioration of presenting signs and symptoms) occurred in 98.6% of lomefloxacin-treated patients and in 95.7% of patients treated with ciprofloxacin. The differences in outcome between the two treatment groups were not statistically significant. Both drug regimens were well tolerated. There were no clinically significant changes in clinical laboratory values during treatment. In the lomefloxacin group three patients reported nausea, one nervousness, and one pruritus; in the ciprofloxacin group, two patients reported nausea and three pruritus. Two lomefloxacin-treated patients (3%) and four patients treated with ciprofloxacin (5%) withdrew from treatment because of adverse events. A single daily dose of 400 mg lomefloxacin was comparable to 500 mg ciprofloxacin every 12 hours for the treatment of complicated or recurrent urinary tract infections.

Adult

Ecological effects of short-term ciprofloxacin treatment of travellers' diarrhoea.

Forty-two subjects travelling to Mexico for 11 days were enrolled in a randomized, double-blind, placebo-controlled trial comparing ciprofloxacin 250 mg twice daily for three days or placebo for treatment of travellers' diarrhoea. Seventeen (41%) subjects were randomized to treatment. By the last treatment day, all seven evaluable subjects in the ciprofloxacin group, and three of eight evaluable subjects in the placebo group were cured (P = 0.04). The mean time to cure was 26 h for ciprofloxacin and 60 h for placebo-treated patients (P = 0.03). Faecal specimen were collected pre-travel, after four days in Mexico, 48 h post-travel and four weeks post-travel. Potentially pathogenic Escherichia coli strains carrying diarrhoeagenic virulence genes were detected by DNA hybridization tests, during or after travel, in 41% of treated and 31% of asymptomatic travellers. Travel, irrespective of diarrhoea and type of treatment, had a minor impact on the aerobic and anaerobic microflora. In travellers with ongoing diarrhoea, a suppression of the numbers of anaerobic bacteria was found, but the microflora was otherwise virtually unaffected. Significantly increased frequencies of E. coli resistant to ampicillin, doxycycline, chloramphenicol and co-trimoxazole were found during and after travel in all categories of travellers, though more frequently in subjects who experienced diarrhoea. The susceptibility of Bacteroides spp. remained unchanged. The sensitivity of E. coli to ciprofloxacin was not affected by travel, except in four ciprofloxacin-treated subjects who acquired multiresistant E. coli with ciprofloxacin MICs of > or = 0.125 mg/L post-travel. Bacteroides strains with MICs of > or = 64 mg/L were isolated post-travel from four ciprofloxacin-treated patients, and from one of the other 34 travellers not treated with ciprofloxacin.

Administration, Oral

Ciprofloxacin and Clostridium difficile-associated diarrhoea.

Recent reports have implicated ciprofloxacin as a cause of Clostridium difficile-associated diarrhoea. This problem was examined in three ways. First, the MIC of ciprofloxacin for C. difficile was determined. The MIC range was 8-32 mg/L, with C. difficile were 'treated' with ciprofloxacin and clindamycin in a test-tube, and the growth of C. difficile monitored. The clindamycin-treated emulsions supported growth of C. difficile, while the ciprofloxacin-treated and control emulsions did not differ significantly and failed to support the growth of C. difficile. Finally, 213 patients on ciprofloxacin monotherapy were investigated. Twenty-nine patients were given ciprofloxacin as treatment for diarrhoea, while a further 15 patients developed diarrhoea while being treated. None of these 44 patients harboured C. difficile. Faecal samples from 73 of the remaining 169 patients who did not have or develop diarrhoea were investigated for C. difficile, but none was positive. It was concluded that ciprofloxacin is unlikely to promote C. difficile-associated diarrhoea.

Ciprofloxacin

Genetic mutations driving ciprofloxacin resistance in laboratory-evolved Salmonella Typhimurium.

Ciprofloxacin resistance in Salmonella Typhimurium is a significant public health concern, and the mechanisms by which the resistance evolves are poorly defined. Here, by serial passaging under antibiotic selection, we isolated ciprofloxacin-resistant S. Typhimurium mutants and subjected them to whole-genome sequencing to reveal the major mutations associated with resistance. The Low CipR mutant acquired four chromosomal mutations in ramR, icdA, lipB, and gyrA, and the High CipR mutant gained additional mutations in gyrB, yaiC, and corA. Functional characterization determined that mutations in ramR resulted in efflux pump upregulation, while disruptions in the TCA cycle caused by mutations in icdA and lipB led to metabolic alterations. These changes indirectly enhanced resistance by increasing the expression of the global regulator MarA and reducing OmpF-dependent membrane permeability. Despite the observation of the G105A substitution in GyrA, enzymatic assays confirmed the failure to support resistance to ciprofloxacin, possibly because the structural alteration remained minimal. GyrB488-489dup was associated with maintained supercoiling under ciprofloxacin and enhanced fluoroquinolone resistance, suggesting a major role in resistance evolution. Other mutations in yaiC impaired biofilm and, in corA, intracellular accumulation of magnesium, possibly stabilizing the bacterial cell envelope under antibiotic pressure. The findings provide novel explanations for the multifaceted mechanisms leading to ciprofloxacin resistance in Salmonella and suggest targets to combat antimicrobial resistance.IMPORTANCEAntibiotic resistance in Salmonella Typhimurium is an increasing public health concern, yet the genetic changes that allow bacteria to become resistant are not fully understood. In this study, we evolved ciprofloxacin-resistant Salmonella in the laboratory and identified the mutations that arise during resistance development. We found that resistance does not result from a single change but from multiple adaptations affecting drug efflux, metabolism, and the antibiotic target. Some mutations increased the activity of pumps that remove antibiotics from the cell, while others altered bacterial metabolism and reduced membrane permeability, making it harder for the drug to enter. A duplication in the DNA gyrase subunit GyrB played a particularly important role in maintaining DNA function under antibiotic stress. Together, these results reveal how diverse genetic changes cooperate to generate ciprofloxacin resistance and provide insights that may help guide strategies to combat drug-resistant Salmonella infections.

DNA gyrase

Bactericidal activity of ciprofloxacin upon Escherichia coli and Acinetobacter baumanni.

The mechanisms of bactericidal activity of ciprofloxacin (mechanisms A and B) upon cells of a strain of Escherichia coli and one strain of Acinetobacter baumannii were investigated under different conditions. The killing of E. coli cells by ciprofloxacin was significantly reduced by chloramphenicol, but this antibiotic showed almost no activity upon killing of A. baumannii cells by this quinolone. Similar results were obtained when rifampicin was added to ciprofloxacin. Bactericidal activity of ciprofloxacin upon nondividing cells of E. coli was lower and that upon non-dividing cells of A. baumannii was not affected when compared with activity of ciprofloxacin upon dividing cells of both microorganisms. These results demonstrate that the antibacterial activity of ciprofloxacin upon A. baumannii is independent of protein and ARN synthesis, a fact which suggests that this quinolone exerts only bactericidal mechanism B upon A. baumannii. This finding might explain, at least in part, the lower susceptibility of this microorganism to ciprofloxacin.

Acinetobacter

Ciprofloxacin versus trimethoprim-sulfamethoxazole: treatment of community-acquired urinary tract infections in a prospective, controlled, double-blind comparison.

In this study, we determined the safety and efficacy of the treatment of adults with urinary tract infection with ciprofloxacin hydrochloride (250 mg twice daily for 10 days) in comparison with trimethoprim-sulfamethoxazole (160 mg of trimethoprim and 800 mg of sulfamethoxazole twice daily for 10 days). Patients with signs and symptoms of urinary tract infection were randomized to receive ciprofloxacin (98 women and 5 men) or trimethoprim-sulfamethoxazole (92 women and 8 men). The success rate of therapy was 91% for both treatment arms of the study. Among seven failures after ciprofloxacin therapy, three were due to relapse of infection and two to side effects that necessitated a change in medication; in addition, two patients had persistent symptoms and required hospitalization. Among the six failures associated with trimethoprim-sulfamethoxazole therapy, four were due to relapse, one to persistence of infection, and one to a side effect that necessitated a change in medication. Among the patients treated with trimethoprim-sulfamethoxazole, 32% had mild or moderate adverse reactions; in comparison, 17% of the ciprofloxacin-treated patients had adverse reactions (P = 0.026). For the treatment of urinary tract infection in adult patients in this study, ciprofloxacin and trimethoprim-sulfamethoxazole were equally effective, but ciprofloxacin was associated with fewer adverse reactions.

Adult

Comparative clinical and microbiological study of amoxycillin-clavulanic acid and ciprofloxacin in acute purulent exacerbations of chronic bronchitis.

In a retrospective study, the clinical and microbiological efficacy of amoxycillin-clavulanic acid and ciprofloxacin were evaluated in outpatients observed within the previous year who were affected by acute purulent exacerbations of chronic bronchitis. Of the 95 patients included in the trial, 50 received amoxycillin 875 mg-clavulanic acid 125 mg 8-hourly for 10 days and 45 received ciprofloxacin 500 mg 12-hourly before meals for 10 days. Of the amoxycillin-clavulanic acid-treated patients, 90% showed clear clinical improvement and in 10% treatment failed. In the ciprofloxacin group, 75.5% of patients showed improvement and in 24.5% treatment failed. All pathogens isolated prior to therapy were susceptible to the antibiotic used for therapy. At the end of treatment, in the amoxycillin-clavulanic acid-treated group, 84% of strains were eradicated and 8% persisted; others were superinfections. In the ciprofloxacin group, 57.7% of strains were eradicated, 26.6% persisted and 15.5% were superinfections. No clinically significant side effects were observed in either group. Overall, amoxycillin-clavulanic acid demonstrated superior clinical and microbiological efficacy to ciprofloxacin, although this might be attributable to the higher proportion of aerobic Gram-negative pathogens in the ciprofloxacin group.

Adult

Effects of temafloxacin and ciprofloxacin on the pharmacokinetics of caffeine.

A number of quinolone antibacterial agents, particularly enoxacin, pefloxacin, pipemidic acid and ciprofloxacin, are known to decrease the clearance of methylxanthines. The effects of temafloxacin and ciprofloxacin on the pharmacokinetics of caffeine were therefore compared in a 3-way crossover study in 12 healthy young volunteers. Each volunteer received 183mg once-daily doses of caffeine in conjunction with twice-daily placebo, temafloxacin 600mg and ciprofloxacin 750mg in 3 separate phases according to a randomised sequence. A doubling of the area under the plasma concentration-time curve (77.8 vs 31.8 mg/L.h) and terminal-phase half-life (9.7 vs 4.5h) of caffeine were observed in the presence of ciprofloxacin. The magnitude of the reduction in the intrinsic clearance of caffeine produced by ciprofloxacin was greater than that described in the literature for ciprofloxacin and theophylline. This may partly be explained by intertrial differences in dosage and study design. Coadministration of temafloxacin did not have any effect on the pharmacokinetics of caffeine, confirming results of other studies suggesting that this agent does not affect methylxanthine clearance. Accordingly, it appears that restriction of caffeine intake during temafloxacin therapy is not necessary.

Adult

Methicillin-resistant Staphylococcus aureus keratitis in the rabbit: therapy with ciprofloxacin, vancomycin and cefazolin.

To determine the efficacy of a fluoroquinolone antibiotic in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) keratitis, topical administration of 0.3% ciprofloxacin was compared with topical 5.0% vancomycin or 5.0% cefazolin in experimental infections in the rabbit eye. The infections were established by intrastromal injection of 100 colony forming units (CFU) of MRSA, which resulted in greater than 10(6) CFU per cornea by 12 hr postinfection. Chemotherapy (one drop every 15 min) was given from 4-9, 10-15, or 10-20 hr postinfection. Early therapy (4-9 hr postinfection) with ciprofloxacin rendered all eyes free of bacteria; ciprofloxacin was significantly more effective than vancomycin or cefazolin. When treatment was initiated 6 hr later (10-15 hr postinfection), no corneas became free of bacteria, but ciprofloxacin was again more effective than vancomycin or cefazolin. Bacterial killing by ciprofloxacin after treatment from 10-20 hr postinfection was also significantly greater than that of vancomycin. Overall, the results show that ciprofloxacin is effective in killing methicillin-resistant staphylococcus aureus, and is most effective when applied during the very early stages of infection.

Animals

Ciprofloxacin-impregnated poly-L-lactic acid drug carrier. New aspects of a resorbable drug delivery system in local antimicrobial treatment of bone infections.

Resorbable poly-L-lactic acid (PLLA) cylinders (3.5 mm diameter, 5 mm in length) carrying 6% of weight ciprofloxacin (Ciprobay, Bayer AG, Leverkusen, FRG) were investigated in vitro to explore their properties as a slow-release antibiotic deposit. Forty bioactive cylinders stored in test tubes were covered with phosphate buffer (pH 7.4 at 37 degrees C) and 40 with fresh human blood plasma and tested under various conditions. For comparison a gentamicin-polymethylmethacrylate (PMMA) chain (Septopal, E. Merck, Darmstadt, FRG) was exposed to similar test conditions. The quantities of ciprofloxacin and gentamicin released were analysed by a microbiological method (bioassay). The concentrations of ciprofloxacin released were analysed by a microbiological method (bioassay). The concentrations of ciprofloxacin released from 40 cylinder were initially very high (up to 180 mg/l) but they decreased rapidly within the first 5 days (4.2-22.5 mg/l). Early release of gentamicin reached up to 227.5 mg/l but dropped to of 22 mg/l on the 14th day. Complete degradation of the PLLA-cylinders was not seen in the observed period of 92 days. The mean loss of mass was 8.4%. The recovery of incorporated ciprofloxacin was 6.5% on average.

Biological Assay

Transintestinal elimination of ciprofloxacin in humans--concomitant assessment of its metabolites in serum, ileum and colon.

Ciprofloxacin (200 mg) was infused to seven patients at the beginning of elective colorectal surgery. Thirty minutes after the end of infusion (i.e. 60 min after the start of the operation) ciprofloxacin reached concentrations of 1.60 mg/l in serum and of 3.42-6.07 mg/kg fresh weight in the ileum and colon. During the next 30 min (90 min after the start of operation) the concentration of ciprofloxacin in serum decreased to 86% of its initial level, but this decrease was less rapid than that observed in the ileal (to 56.8%) or colonic (to 74.8%) mucosa. Three metabolites could be identified (desethylen-, sulpho-, oxociprofloxacin). Initially, at 60 min the amount of these metabolites was about 15% of the total drug concentration in serum, but only 2-3% of that in the gut tissues. At 90 min the relative amount of metabolites was increased in serum as well as in the gut tissues. It is concluded that transintestinal elimination of ciprofloxacin is a general feature of the whole gut. Obviously, the elimination process is not due to degradation of ciprofloxacin within the gut wall.

Adult

Improved high-performance liquid chromatographic determination of ciprofloxacin and its metabolites in human specimens.

A simple approach to the quantitation of ciprofloxacin and its three metabolites, M1 (desethylene-ciprofloxacin), M2 (sulfo-ciprofloxacin) and M3 (oxo-ciprofloxacin), in human serum, urine, saliva and sputum is described. This assay allows the parent drug and its metabolites to elute and be resolved in a single chromatogram at 280 nm using a linear gradient. The procedure involved liquid-liquid extraction. Separation was achieved on a C18 reversed-phase column. The limit of detection of ciprofloxacin is 0.05 microgram/ml and that of its three metabolites is 0.25 microgram/ml. This method is sufficiently sensitive for pharmacokinetic studies.

Chromatography, High Pressure Liquid