Ciprofloxacin in the treatment of urinary tract infection due to enterobacteria

Investigations of the antibacterial properties of ciprofloxacin@SiO2

The antibacterial activity of ciprofloxacin-encapsulated silica nanoshells synthesized from gold@silica core-shell nanoparticles has been investigated. The minimum inhibitory concentration of the material was found using the agar dilution method, and it showed better antibacterial activity compared to free ciprofloxacin in the case of Escherichia coli DH5, whereas the same activity was found for Lactococcus lactis MG 1363. Hydrophobicity measurements carried out in an octanol-water mixture suggested that ciprofloxacin@SiO2 is distributed almost equally in the aqueous and nonaqueous phases. The kinetics of the uptake of ciprofloxacin@SiO2 was compared with that of free ciprofloxacin. Fluorescence imaging studies carried out using fluorescein isothiocyanate@SiO2 showed that the nanoshells enter the bacterial cell. The uptake of silica shells has been probed by transmission electron microscopy also.

Clinical applications of quinolones

The quinolone antimicrobials are the class of inhibitors of bacterial topoisomerases that has been developed most fully for clinical use in human medicine. Initial members of the class had their greatest potency against Gram-negative bacteria, but newly developed members have exhibited increased potency against Gram-positive bacteria and soon agents will be available with additional activity against anaerobic bacteria, providing a broad spectrum of potency. After nalidixic acid, the earliest member of the class which was used for treatment of urinary tract infections, the later fluoroquinolone congeners have had sufficient potency, absorption, and distribution into tissue for additional uses in treatment of sexually transmitted diseases, infections of the gastrointestinal tract, respiratory tract, skin, and bones and joints. Tolerability of these agents in usual doses has been good. Acquired bacterial resistance resulting from clinical uses has occurred in particular among staphylococci and Pseudomonas aeruginosa. Intense drug use and ability of resistant pathogens to spread have also contributed to development of resistance in initially more susceptible pathogens such as Escherichia coli and Neisseria gonorrhoeae in certain settings. Preservation of the considerable clinical utility of the quinolone class for the long term will be affected by the extent to which their use is judicious.

Treatment of chronic bacterial prostatitis with temafloxacin

In an open multicenter study [corrected], 112 male patients (mean age 47.1 years) with documented symptomatic chronic bacterial prostatitis were treated with oral temafloxacin 400 mg b.i.d. for 28 days. Urine and prostatic secretions were obtained for culture and susceptibility testing, and clinical signs and symptoms were evaluated at day 14 as well as 5-9 days and 26-30 days post-treatment. The most frequently isolated pretreatment pathogens (n = 97) were 36 strains (38%) of Escherichia coli and 16 strains (17%) of Enterococcus. Clinical success (cure plus improvement) was demonstrated in 74 of 81 (91%) patients at visit 4, 5-9 days post-treatment and at visit 5, 26-30 days post-treatment in 61 of 71 (86%) patients. At visit 4, 94% of patients had eradication of pretreatment pathogens. At visit 5, 92% had continued eradication of their original pathogens. Improvement was observed in the severity of signs and symptoms that existed pretreatment at visit 4 (visit 5): dysuria, 92% (93%); perineal pain, 95% (93%); lower abdominal pain, 93% (100%); lower back pain, 88% (93%); scrotal/penile pain, 91% (83%). Digestive system (6.3%) and nervous system (4.5%) adverse events were observed most frequently. Temafloxacin 400 mg b.i.d. administered orally for 28 days represents a safe and effective treatment for chronic bacterial prostatitis.

The role of quinolones in the treatment of chronic bacterial prostatitis

Chronic bacterial prostatitis is a rare infection but difficult to treat. Usually co-trimoxazole has been used, yet with poor results. Because of their favorable pharmacokinetics and their broad antibacterial spectrum, the newer quinolones may be a good alternative. In contrast to beta-lactam antibiotics their concentrations in prostatic fluid, in prostatic tissue and in seminal fluid are relatively high in comparison to the corresponding plasma concentrations. For prostatic fluid measurements, however, possible urinary contamination has to be considered and identified otherwise falsely high levels are measured. A total of 23 studies with the newer quinolones (norfloxacin, ciprofloxacin, ofloxacin, pefloxacin, enoxacin, temafloxacin and rufloxacin) in the treatment of chronic bacterial prostatitis are available. However, the results of these studies are difficult to compare because not all investigators used the same diagnostic criteria and there was a considerable range of duration of treatment and of follow-up. Since the issue involved in the treatment of prostatitis is that of relapse, patients cannot be considered cured if they have been followed for one week or one month only. There were four studies among the 23 publications, i.e. one with norfloxacin and three with ciprofloxacin, which fulfilled the criteria of standardized prostatic localization and of long-term follow-up of at least six months. The results are promising, but further investigations, especially controlled studies, are needed in order to determine the role of the newer quinolones in the treatment of chronic bacterial prostatitis.

Use of quinolones in treatment of prostatitis and lower urinary tract infections

The newer quinolones, ciprofloxacin, enoxacin, fleroxacin, lomefloxacin, norfloxacin, ofloxacin and pefloxacin are highly effective antimicrobial agents against the majority of bacteria responsible for urinary tract infections and bacterial prostatitis. The pharmacokinetic properties of these agents after oral administration result in high concentrations in human urine, as well as in prostatic fluid and prostatic tissue. Ciprofloxacin, enoxacin and lomefloxacin produce the highest concentrations in prostatic tissue, followed by norfloxacin, ofloxacin and fleroxacin. More than 400 patients with chronic bacterial prostatitis have been treated with one of the newer quinolones in varying doses for 10 to 84 days. The results indicate a cure rate of approximately 70%, although the follow-up period is quite variable in these studies. Clinical trials of short-term (single dose vs three days) therapy with the newer quinolones conducted in women with uncomplicated lower urinary tract infections were reviewed. Although bacteriologic cure rates were high with single doses of ciprofloxacin, fleroxacin, norfloxacin, ofloxacin and pefloxacin, approximately one in five women with suspected uncomplicated lower urinary tract infection experience failure of single-dose therapy. In contrast, a three-day regimen with these agents is more effective than a single-dose in the treatment of uncomplicated lower urinary tract infections in women.

Ciprofloxacin. Best use of this new broad-spectrum antibiotic

Resistance to traditional antibiotics is an increasing problem. The introduction of ciprofloxacin (Cipro) has been welcome, because it is safe and effective against many organisms (including drug-resistant ones), can be taken orally, and is well tolerated. Dr Fass provides a complete description of the drug, including its use for infections of the urinary, respiratory, and gastrointestinal tracts; skin and skin structures; and bones and joints.

Comparison of three dosage regimens of ciprofloxacin in urinary tract infections

Fifty-four patients with complicated UTI were administered ciprofloxacin in doses of 500 mg (30 subjects) and 250 mg (24 subjects) at 12-hour intervals. While a positive effect was noted in 96-100% upon termination of therapy, the effect was still present 3 weeks later in 90% of the high-dose, but only in 71% of the low-dose group. In 23 patients with uncomplicated UTI, a positive effect of the three-day therapy with 100 mg of ciprofloxacin at 12-hour intervals was observed in 91% of subjects. Intolerance to the agent was found in one case only. Development of resistance to ciprofloxacin was not observed.

Quinolone antimicrobial agents: adverse effects and bacterial resistance

Adverse effects, drug-drug interactions and bacterial resistance to the new quinolone antimicrobial agents are reviewed. Clinical adverse effects are reported to occur in 5-10% of patients, and include primarily gastrointestinal disturbances, central nervous system toxicity and rash. Laboratory abnormalities are reported to occur in 5-12% of patients, and include mild reversible elevations of transaminases. Quinolones are not recommended in persons whose bone growth is incomplete or in pregnant or nursing women because cartilage toxicity has been observed in juvenile beagles. Drug-drug interactions may occur between quinolones and theophylline, caffeine, and magnesium- or aluminium-containing compounds such as antacids and sucralfate. Bacterial resistance occurs by chromosomal mutations which alter the target enzyme DNA gyrase or decrease drug accumulation. Emergence of resistance during therapy is uncommon to date but can be problematic in infections with Pseudomonas aeruginosa. Staphylococcus aureus and other bacteria for which the therapeutic index may be low. In summary, quinolones thus far have been well tolerated, but more experience is needed to determine the exact nature and extent of adverse effects and emergence of bacterial resistance.

Fluoroquinolone antimicrobial agents

The fluoroquinolones, a new class of potent orally absorbed antimicrobial agents, are reviewed, considering structure, mechanisms of action and resistance, spectrum, variables affecting activity in vitro, pharmacokinetic properties, clinical efficacy, emergence of resistance, and tolerability. The primary bacterial target is the enzyme deoxyribonucleic acid gyrase. Bacterial resistance occurs by chromosomal mutations altering deoxyribonucleic acid gyrase and decreasing drug permeation. The drugs are bactericidal and potent in vitro against members of the family Enterobacteriaceae, Haemophilus spp., and Neisseria spp., have good activity against Pseudomonas aeruginosa and staphylococci, and (with several exceptions) are less potent against streptococci and have fair to poor activity against anaerobic species. Potency in vitro decreases in the presence of low pH, magnesium ions, or urine but is little affected by different media, increased inoculum, or serum. The effects of the drugs in combination with a beta-lactam or aminoglycoside are often additive, occasionally synergistic, and rarely antagonistic. The agents are orally absorbed, require at most twice-daily dosing, and achieve high concentrations in urine, feces, and kidney and good concentrations in lung, bone, prostate, and other tissues. The drugs are efficacious in treatment of a variety of bacterial infections, including uncomplicated and complicated urinary tract infections, bacterial gastroenteritis, and gonorrhea, and show promise for therapy of prostatitis, respiratory tract infections, osteomyelitis, and cutaneous infections, particularly when caused by aerobic gram-negative bacilli. Fluoroquinolones have also proved to be efficacious for prophylaxis against travelers' diarrhea and infection with gram-negative bacilli in neutropenic patients. The drugs are effective in eliminating carriage of Neisseria meningitidis. Patient tolerability appears acceptable, with gastrointestinal or central nervous system toxicities occurring most commonly, but only rarely necessitating discontinuance of therapy. In 17 of 18 prospective, randomized, double-blind comparisons with another agent or placebo, fluoroquinolones were tolerated as well as or better than the comparison regimen. Bacterial resistance has been uncommonly documented but occurs, most notably with P. aeruginosa and Staphylococcus aureus and occasionally other species for which the therapeutic ratio is less favorable. Fluoroquinolones offer an efficacious, well-tolerated, and cost-effective alternative to parenteral therapies of selected infections.

Quinolones in urology

The new quinolones have broad antimicrobial spectra covering all aerobic gram-negative and gram-positive bacteria encountered in urinary tract infections. All are administered orally, some also parenterally, low degree of resistance, few side effects and bacteriological and clinical cure rates similar to or higher than traditional antimicrobials make them especially suitable for treatment of complicated urinary tract infections including bacterial prostatitis. Non-critical use of quinolones in simple infections where standard drugs may be equally effective and safe should be discouraged.

Ciprofloxacin in elderly patients with underlying chronic diseases

Age is not as important in predisposing to infections as are the associated problems peculiar to certain age groups. Factors such as the advanced age of the patients combined with the presence of chronic disease reduce their resistance to infection. This study comprises 212 elderly patients (aged 65-98 years) who were treated with 500-1000 mg/day ciprofloxacin for 1-18 days. Despite the high incidence of associated chronic diseases, microbiology showed that infections were eradicated in 88.5%. Clinical resolution occurred in 75.5% of patients and clinical failure occurred in 6.1%. Treatment was well tolerated, with clinical side-effects reported in only seven patients. Ciprofloxacin may be considered an effective and safe antimicrobial agent for the treatment of infections in the elderly.

Ciprofloxacin in management of urinary tract infection

Ciprofloxacin is a new quinolone derivative which is particularly well adapted for the treatment of bacterial urinary tract infection. Virtually all uropathogens are susceptible, and the development of resistance is uncommon. Its pharmacokinetic characteristics reveal that effective concentrations of the drug are easily achieved with twice a day oral therapy in the blood, urine, kidneys, and prostate--even in advanced renal failure. The drug is well tolerated, even with prolonged courses of therapy. It will be particularly useful in the treatment of antibiotic-resistant, complicated, and/or prostatic infection.

Ciprofloxacin: chemistry, mechanism of action, resistance, antimicrobial spectrum, pharmacokinetics, clinical trials, and adverse reactions

Ciprofloxacin, considered a benchmark when comparing new fluoroquinolones, shares with these agents a common mechanism of action: inhibition of DNA gyrase. While ciprofloxacin demonstrated a fairly good activity against gram-positive bacteria, it is against gram-negative organisms that it proved to be more potent than other fluoroquinolones. It is the most active quinolone against Pseudomonas aeruginosa, with MIC90s on the order of 0.5 micrograms/ml. When given orally, ciprofloxacin exhibited 70% bioavailability and attained peak serum levels ranging between 1.5 and 2.9 micrograms/ml after a single 500-mg dose. Nineteen percent of an oral dose was excreted as metabolites in both urine and feces. In most cases, body fluids and tissue concentrations equaled or exceeded those in concurrent serum samples. In clinical trials, oral and intravenous ciprofloxacin yielded similar clinical and bacteriologic results compared to standard therapy in a wide array of systemic infections, including lower and upper urinary tract infections; gonococcal urethritis; skin, skin structure, and bone infections; and respiratory tract and gastrointestinal tract infections. Major benefits with the oral form of this quinolone are expected in chronic pyelonephritis and bone infections, and in pulmonary exacerbations in patients with cystic fibrosis. Emergence of ciprofloxacin-resistant microorganisms has been noted in clinical practice, primarily Pseudomonas aeruginosa and Staphylococcus aureus. The most frequent side effects are related to the gastrointestinal tract; but attention should be given to adverse central nervous system effects.

Worldwide clinical data on efficacy and safety of ciprofloxacin

During the clinical trials 8,861 patients have been treated with ciprofloxacin worldwide. 3,822 of the therapeutic courses were valid for analysis of efficacy according to FDA standards. The following dosages were usually administered: UTI: 100 to 500 mg twice daily orally or 100 mg twice daily intravenously; RTI: 250 to 1000 mg twice daily orally or 200 mg twice daily intravenously; septicemia: 200 mg intravenously twice daily; gonorrhea: 250 to 500 mg single tablet orally; all other infections: 500 to 1000 mg twice daily orally or 200 mg twice daily intravenously. Ciprofloxacin was administered to 762 courses of lower RTI, 88 courses of upper RTI, 108 courses of bacteremia, 766 courses of skin structure infection, 142 courses of bone and joint infections, 149 courses of intra-abdominal infections, 33 courses of gastrointestinal infections, 1,633 courses of UTI, 49 courses of pelvic infections, 279 courses of STD, mainly gonorrhea, and three courses of meningitis. The clinical response was resolution in 76%, improvement in 18% and failure in only 6%. Bacteriologic response by all sites evaluable: pathogens were eradicated from 74%, markedly reduced in 2%, persisted in 10%. Relapse occurred in 4% and reinfection was observed in another 6%. The overall response was favourable for 90% of the patients. Drug safety was established on a data base of 8,861 courses worldwide. The following side-effects according to COSTART terminology were observed: digestive 5%, metabolic nutritional 4.6%, central nervous 1.6%, skin 1.4%, hemic and lymphatic 1%, cardiovascular 0.4%, body as a whole 0.4%, urogenital 0.3%, special senses 0.3%, musculo-skeletal 0.1%, respiratory 0.08%. Several courses had more than one reaction. Thus the total incidence of side-effects for the treated patient population was 10.2%. Ciprofloxacin is a highly effective drug and a breakthrough in several areas of medical interest. It is relatively safe and side-effects are usually mild or moderate in intensity and transient.

Ciprofloxacin in the treatment of urinary tract infections

Twenty patients (15 males; five females) aged 11-70 years, with urinary tract infections were treated with one 250 mg tablet of ciprofloxacin every 12 h for 5-10 days. Clinical response to this treatment was the complete disappearance of symptoms in 85% of cases and the elimination of the micro-organism responsible for infection. In only three patients, who all had urinary calculus in addition to an infection, clinical failure of the therapy occurred and the causative micro-organism persisted. Tolerance to the therapy was excellent in this study, no adverse reactions connected with the treatment being reported.

Development of resistance during antibiotic therapy

The frequency of development of resistance during antibiotic therapy was evaluated by reviewing the literature according to prescribed criteria. Mean resistance rates were calculated to be 9.2% for broad spectrum penicillins, 8.6% for second and third generation cephalosporins, 10.0% for latamoxef, 4.7% for imipenem, 11.8% for ciprofloxacin and 13.4% for aminoglycosides. Emergence of resistance of the infecting organism was associated with therapeutic failure in about half of the cases with the exception of patients treated with aminoglycosides in whom development of resistance resulted in treatment failure in 85% of the cases. The possible benefit of combination therapy in terms of resistance development is discussed.

Efficacy and safety of oral ciprofloxacin for treatment of serious urinary tract infections

Eighty-three patients with serious urinary tract infections were treated with oral ciprofloxacin. Of these patients, 79 were hospitalized, and 41 had known structural or neurologic abnormalities of the urinary tract. The most common pathogens were members of the family Enterobacteriaceae (MICs, less than or equal to 0.06 microgram/ml), Pseudomonas aeruginosa (MICs, 0.13 to 2 micrograms/ml), and Enterococcus faecalis (MICs, 0.5 to 2 micrograms/ml). Sixty-eight patients were able to be evaluated for determining efficacy; all responded symptomatically, and all urinary pathogens were eradicated on days 3 to 5 of treatment. Five patients, who were treated for a relatively short duration (2 to 10 days), relapsed 5 to 9 days posttreatment. Six patients became colonized with yeasts during treatment, and seven patients developed bacterial reinfections 5 to 9 days posttreatment. All patients whose infections relapsed or who developed infections with new organisms had neurogenic bladders, structural abnormalities of the genitourinary tract, or urinary catheters. There was no instance of bacteria developing resistance during treatment. Ciprofloxacin probably caused nausea with or without vomiting in 7 of the 83 patients, headache in 3 patients, and mild elevation of hepatic enzymes in 2 patients; other adverse reactions were observed but were probably not drug related. Oral ciprofloxacin was effective and safe for the treatment of serious urinary tract infections caused by a variety of bacterial pathogens.