In vitro antibacterial activities of AF 3013, the active metabolite of prulifloxacin, against nosocomial and community Italian isolates

A randomized, controlled trial of prulifloxacin as conversion therapy after intravenous carbapenem in the treatment of acute pyelonephritis caused by third generation cephalosporin resistant pathogens: A pilot study

The efficacy of converting to oral fluoroquinolones after initial intravenous antibiotics for the treatment of acute pyelonephritis (APN) caused by the third-generation cephalosporin resistant Enterobacteriaceae (3-GCrEC) needs to be investigated. The objective was to compare the clinical and bacteriological outcome of oral prulifloxacin with intravenous ertapenem for the treatment of APN caused by 3-GCrEC. A pilot, randomized controlled trial of patients with APN caused by 3-GCrEC was conducted at two hospitals from August 2015 to December 2020. Any intravenous antimicrobial drug was initially permitted for empirical therapy. On day 4, adult patients (aged >18 years) with either non-bacteremic or bacteremic APN were eligible for the study if their infection was caused by 3-GCrEC susceptible to the study drugs. The patients were randomly assigned to receive either oral prulifloxacin or intravenous ertapenem. The total duration of antimicrobial therapy was 14 days. Of the 21 enrolled patients, 11 were treated with prulifloxacin, and 10 were treated with ertapenem. At the test of cure visit, there was no statistically significant difference between the patients with overall clinical success who were treated with prulifloxacin (90.9%) and those treated with ertapenem (100%, p = 0.999). In addition, there was no statistically significant difference in microbiological eradication between the prulifloxacin and ertapenem groups (100% vs. 100%, p = 0.999). The converting to oral prulifloxacin after intravenous antibiotics therapy appears to be an alternative option for treatment of APN caused by 3-GCrEC. A further large randomized controlled trial should be investigated.

Susceptibility of Urinary Tract Bacteria to Newer Antimicrobial Drugs

Urinary tract infections (UTIs) are among the commonest types of bacterial infections. The antibiotic treatment for UTIs is associated with important medical and economic implications. Many different microorganisms can cause UTIs though the most common pathogens are E. coli and members of family Enterobacteriaceae. The knowledge of etiology and antibiotic resistance pattern of the organisms causing urinary tract infection is essential. The present study was undertaken to evaluate trends of antibiotic susceptibility of commonly isolated uropathogens using newer antimicrobial agents, prulifloxacin, fosfomycin (FOM) and doripenem. We conclude that maintaining a record of culture results and the antibiogram may help clinicians to determine the empirical and/or specific treatment based on the antibiogram of the isolate for better therapeutic outcome.

Fabrication of stimulus-responsive diatom biosilica microcapsules for antibiotic drug delivery

In this report, we employed surface-initiated atom transfer radical polymerisation to graft thermo-responsive copolymers of oligo(ethylene glycol) methacrylates from the surface of diatom biosilica microcapsules. We demonstrate the application of the resulting composites for thermo-responsive drug delivery.

[Adequacy of antimicrobial therapy in urinary tract infections (UTI).]

Urinary tract infections are one of the most common reasons for antimicrobial prescriptions, however urine cultures are often unavailable and the choice of antibiotics is therefore empiric. The ideal antimicrobial agent must have specific pharmacokinetic and pharmacodynamic characteristics and an adequate spectrum of activity in order to obtain the potential eradication of the pathogen from the site of infection, minimizing the risk of recurrences and ensuring the best safety profile. There are several factors to be considered in the therapy choice: the type of infection, the increasing presence of extended-spectrum beta-lactamase (ESBL) producing bacteria showing resistance to most antibiotics and the problem of the bacterial internalization, that is a frequent cause of treatment failure and early recurrences. Prulifloxacin is a recent oral fluoroquinolone antibiotic approved in several European countries for the treatment of lower urinary tract infections and shows some interesting advantages in comparison with other antibiotics.

Antimicrobial activity of prulifloxacin in comparison with other fluoroquinolones against community-acquired urinary and respiratory pathogens isolated in Greece

Prulifloxacin, the prodrug of ulifloxacin, is a broad-spectrum fluoroquinolone rather recently introduced in certain European countries. We compared the antimicrobial potency of ulifloxacin with that of other fluoroquinolones against common urinary and respiratory bacterial pathogens. The microbial isolates were prospectively collected between January 2007 and May 2008 from patients with community-acquired infections in Greece. Minimum inhibitory concentrations (MICs) were determined for ciprofloxacin, levofloxacin, moxifloxacin (for respiratory isolates only), and ulifloxacin using the E-test method. The binary logarithms of the MICs [log2(MICs)] were compared by using the Wilcoxon signed-ranks test. A total of 409 isolates were studied. Ulifloxacin had the lowest geometric mean MIC for the 161 Escherichia coli, 59 Proteus mirabilis, and 22 Staphylococcus saprophyticus urinary isolates, the second lowest geometric mean MIC for the 38 Streptococcus pyogenes respiratory isolates (after moxifloxacin), and the third lowest geometric mean MIC for the 114 Haemophilus influenzae and the 15 Moraxella catarrhalis respiratory isolates (after ciprofloxacin and moxifloxacin). Compared with levofloxacin, ulifloxacin had lower log2(MICs) against E. coli (p < 0.001), P. mirabilis (p < 0.001), S. saprophyticus (p < 0.001), and S. pyogenes (p < 0.001). Compared with ciprofloxacin, ulifloxacin had lower log2(MICs) against P. mirabilis (p < 0.001), S. saprophyticus (p = 0.008), and S. pyogenes (p < 0.001), but higher log2(MICs) against H. influenzae (p < 0.001) and M. catarrhalis (p = 0.001). In comparison with other clinically relevant fluoroquinolones, ulifloxacin had the most potent antimicrobial activity against the community-acquired urinary isolates studied and very good activity against the respiratory isolates.

Penetration of prulifloxacin into sinus mucosa of patients undergoing paranasal sinus elective endoscopic surgery

The aim of this study was to assess the concentration of ulifloxacin, the active metabolite of prulifloxacin, in sinuses mucosa and plasma of patients with chronic rhinosinusitis, requiring sinus elective endoscopic surgery. Thirty-nine patients (30 males, 9 females; age range 22-77 years) with chronic sinusitis were enrolled, 35 were treated with the investigational medication. Samples from four untreated patients were used to validate the analytical method, while four treated patients dropped out before surgery. One 600 mg prulifloxacin tablet once daily was administered for 5 days before surgery. The last dosing was scheduled from 2 to 12 hours from tissue and plasma sampling. In each patient, two samples of paranasal sinus mucosa (from ethmoid and turbinate, respectively) and one blood sample were collected. Concentrations of ulifloxacin in plasma and sinuses mucosa were measured using validated bioanalytical LC/MS/MS methods. Individual and mean ulifloxacin concentrations in tissues were always higher than the relevant plasma levels. The highest concentrations were observed between 2.5 and 4.5 hours after the last dosing in all districts. The mean tissue/plasma ratios were 2.5 and 3.0 for ethmoid and turbinate, respectively. Data expressed as Area Under the Curves (AUC±SD) showed that ulifloxacin concentrations in the ethmoid were slightly higher (18.68±6.48 μg/g*h) than in turbinate (15.00±2.89 μg/g*h), and definitely higher than in plasma (6.32±1.14 μg/ml*h). The AUC ratios between tissues and plasma were 3.0 for ethmoides and 2.4 for turbinates. One patient reported two treatment-related episodes of diarrhea, which spontaneously resolved after the drug suspension. Results from this study seem to suggest that prulifloxacin showed good distribution in sinus tissues, where it reaches concentrations significantly higher than in plasma. These findings strongly call for confirmatory clinical trials in patients with bacterial rhinosinusitis.

Prulifloxacin: clinical studies of a broad-spectrum quinolone agent

Prulifloxacin, the lipophilic prodrug of ulifloxacin, is a new oral fluoroquinolone with a broad spectrum of in vitro activity against various Gram-positive and Gram-negative microorganisms. Currently, it is the most potent in vitro fluoroquinolone against Escherichia coli and Pseudomonas aeruginosa, and also has the lowest potential of inducing the emergence of resistant strains for these bacteria. It exhibits good penetration in target tissues and fluids, and possesses a long half-life, thus allowing for once-daily administration. Prulifloxacin has been successfully tested in Phase III randomized, controlled trials including patients with acute exacerbations of chronic bronchitis, uncomplicated and complicated urinary tract infections, and chronic bacterial prostatitis. Results are awaited from recently completed and ongoing Phase III randomized, placebo-controlled studies testing prulifloxacin for the treatment of traveler's diarrhea. Prulifloxacin has an acceptable toxicity profile, comparable to that of other fluoroquinolones, with gastric disturbances, diarrhea, nausea and skin rash of mild-to-moderate severity being the most frequent adverse events. Additional research is needed to further elucidate the promising role of prulifloxacin in the treatment of infections sustained by multidrug-resistant pathogens and to consolidate the wide spectrum of activity from a clinical standpoint.

Antimicrobial activity of prulifloxacin tested against a worldwide collection of gastroenteritis-producing pathogens, including those causing traveler's diarrhea

Prulifloxacin, the prodrug of ulifloxacin (active component), is a newer fluoroquinolone with broad activity against enteric and nonenteric gram-negative bacilli. Ulifloxacin and other oral comparator agents were tested for activity against 582 gastroenteritis strains from global surveillance studies. Ulifloxacin was highly active against Escherichia coli, Salmonella spp., Shigella spp., Yersinia spp., Vibrio spp., Aeromonas spp., and Plesiomonas spp. (MIC(50)s and MIC(90)s, or=4 microg/ml). Ciprofloxacin exhibited similar activity but was two- to fourfold less potent. Presently approved for clinical use in certain European countries and Japan, ulifloxacin was the most active of the antimicrobial agents tested against these gastroenteritis-causing pathogens.

Prulifloxacin in the treatment of acute exacerbations of COPD in cigarette smokers

Smoking is associated with an increased risk of respiratory tract infection in adults likely because components in the smoke might alter properties of the epithelial cell surface. In studies with smokers suffering from acute exacerbations of COPD (AECOPD), the most common bacterial pathogens found were mainly Haemophilus influenzae, but also Streptococcus pneumoniae, Staphylococcus aureus, and Moraxella catarrhalis. Therefore, antibiotics should be effective against such possible pathogens. Prulifloxacin has demonstrated in vitro activity against all these pathogens. We designed the present study to evaluate the efficacy of prulifloxacin in the treatment of AECOPD in cigarette smokers. We enrolled 61 consecutive smokers hospitalized or out-patients of either sex with symptoms and signs compatible with the usual diagnosis criteria for AECOPD. Haemophilus influenzae was the most common bacterial species isolated in the sputum (in 42.6% of the total sample), followed by S. pneumoniae (16.5%), S. aureus (14.7%), M. catarrhalis (11.5%), and others (14.7%). Prulifloxacin 600 mg was given orally once daily for 10 days. Clinical success was observed in 91.8% of patients (67.2% cured and 24.6% improved). Bacteriological eradication rate of H. influenzae was 100%. Persistent pathogens were S. pneumoniae (2 out of 10), S. aureus (1 out of 8), M. catarrhalis (1 out of 7), and P. aeruginosa (1 out of 3). This study seems to indicate that prulifloxacin is of particular value in the treatment of AECOPD in cigarette smokers.

Prulifloxacin: a brief review of its potential in the treatment of acute exacerbation of chronic bronchitis

Exacerbations of chronic bronchitis (AECB) are a major cause of morbidity and mortality in patients with chronic obstructive pulmonary disease (COPD), and their impact on public health is increasing. The new fluoroquinolones have an excellent spectrum providing cover for the most important respiratory pathogens, including atypical and “typical” pathogens. Not surprisingly, different guidelines have inserted these agents among the drugs of choice in the empirical therapy of AECB. The pharmacokinetic and dynamic properties of the new fluoroquinolones have a significant impact on their clinical and bacteriological efficacy. They cause a concentration-dependent killing with a sustained post-antibiotic effect. This review discusses the most recent data on the new fluoroquinolone prulifloxacin and critically analyses its activity and safety in the management of AECB.

In vitro activity of prulifloxacin against Escherichia coli isolated from urinary tract infections and the biological cost of prulifloxacin resistance

Minimum inhibitory concentrations (MICs) and mutant prevention concentrations (MPCs) of prulifloxacin against 30 strains of Escherichia coli isolated from urinary tract infections as well as the 'biological cost' related to acquisition of resistance to the same drug in 10 uropathogenic E. coli were assessed. In terms of MIC(90), prulifloxacin was more potent than ciprofloxacin and levofloxacin. Prulifloxacin produced lower or equal MPC values than the other two fluoroquinolones (93.3% and 73.3% compared with levofloxacin and ciprofloxacin, respectively). Compared with susceptible strains, prulifloxacin-resistant mutants showed a reduced rate of growth (ranging from 20.0% to 98.0% in different culture media and incubation conditions) and a decreased fitness index (ranging from 0.959 to 0.999). They were also impaired in their ability to adhere to uroepithelial cells and urinary catheters (11.7-66.4% and 16.3-78.3% reduction, respectively) and showed a lower surface hydrophobicity (51.2-76.0%). They were more susceptible to ultraviolet irradiation (30.6-93.8% excess mortality), showed increased resistance to colicins and diminished transfer of plasmids (<1-8.5x10(-8) vs. 3.3x10(-7)-2.4x10(-4)). Synthesis of haemolysin and type I fimbriae and production of flagella were also adversely affected. This study demonstrates a strict relationship between acquisition of prulifloxacin resistance and loss of important virulence traits. In this transition, E. coli pays a severe biological cost that entails a general reduction of fitness, thus compromising competition with susceptible wild-type strains in the absence of the drug.

Prulifloxacin: a new antibacterial fluoroquinolone

In the last few years, the antimicrobial activity, efficacy and relative safety of fluoroquinolones have made them attractive for the treatment of community-acquired and nosocomial infections. Prulifloxacin is a new fluoroquinolone antibacterial agent with a broad spectrum of activity against Gram-positive and -negative bacteria. Prulifloxacin is available for oral use, and after absorption is metabolized in to the active form, ulifloxacin. It exhibits good penetration in target tissues and a long elimination half-life, allowing once-daily administration. A number of randomized, controlled clinical trials carried out in Europe demonstrated the efficacy of prulifloxacin in the treatment of urinary tract (acute uncomplicated and complicated) and respiratory tract infections (acute exacerbations of chronic bronchitis), in comparison with the most widely used drugs such as ciprofloxacin, co-amoxiclav and pefloxacin. Prulifloxacin was generally well tolerated. The most frequent adverse reactions observed in clinical trials were gastric pain, diarrhea, nausea and skin rash. This review focuses on the characteristics of prulifloxacin, summarizing the relevant preclinical and clinical data.

The antimicrobial armamentarium: evaluating current and future treatment options

The development and introduction of new antibiotics has, unfortunately, not kept pace with the development of bacterial resistance, and the need for new agents is becoming acute. Although some currently marketed agents remain valuable tools in the treatment of infectious diseases, few new drugs have reached the market in the last decade. In recent years, antibiotics with activity against certain problematic resistant bacteria such as methicillin-resistant Staphylococcus aureus, including linezolid and daptomycin, have been approved for clinical practice. Recently, tigecycline, a minocycline derivative, received approval by the United States Food and Drug Administration for treatment of complicated skin and skin structure and intraabdominal infections; the agent is also active against a variety of multidrug-resistant bacteria. Of the other agents in phase III development, ceftobiprole--a cephalosporin, and faropenem and doripenem--both carbapenems, have wide antibacterial spectra. Antimicrobial agents in the pipeline with marked gram-positive activity include dalbavancin, telavancin, and oritavancin.

Prulifloxacin: A new fluoroquinolone for the treatment of acute exacerbation of chronic bronchitis

Empiric therapy with oral antibiotics is normal practice in the treatment of acute exacerbations of chronic bronchitis (AECB), but there is growing concern regarding efficacy of the currently available antimicrobials. Prulifloxacin, the lipophilic prodrug of ulifloxacin, is an oral fluoroquinolone antibacterial agent with a broad-spectrum in vitro activity against Gram-negative and -positive bacteria, and a long elimination half-life, which allows the once-daily administration. In addition, it penetrates extensively into lung tissues. Statistical analyses indicated a significant linear trend between the prulifloxacin 300, 450, and 600 mg doses, which would point to an interesting relationship between dose employed and response obtained. The 600 mg once-daily dose showed the best risk/benefit ratio, and was selected for use in the pivotal clinical trials. In well-designed clinical trials, prulifloxacin 600 mg administered once daily for 10 days in patients with AECB showed good clinical and bacteriological efficacy (similar to that of ciprofloxacin or co-amoxiclav). In particular, the clinical response rates were favourable in all clinical trials, with eradication rates in patients with pneumococcal infections at least as high as the comparators. It can be concluded that prulifloxacin 600 mg once daily is a new therapeutic prospect in the antimicrobial therapy of AECB. In particular, since good patient compliance is a key factor in the successful treatment of any infection, the once daily treatment with prulifloxacin may have some compliance advantages compared to the twice-daily treatment with agents such as ciprofloxacin or co-amoxiclav.

Highlights on the appropriate use of fluoroquinolones in respiratory tract infections

The impact of respiratory infections on public health is increasing, and lower respiratory tract infections are a major cause of morbidity and mortality. Moreover, most antibiotic prescriptions are related to respiratory infections and this is probably one of the main determinants of the increasing rate of bacterial resistance in both community and hospital settings. This has been the catalyst for the development of new drugs, such as the new fluoroquinolones. The new fluoroquinolones have an excellent spectrum providing cover for the most important respiratory pathogens, including atypical and "typical" pathogens. The pharmacokinetic and dynamic properties of the new fluoroquinolones have a significant impact on their clinical and bacteriological efficacy. They cause a concentration-dependent killing with a sustained post-antibiotic effect. Fluoroquinolones combine exceptional efficacy with cost-effectiveness. Not surprisingly, different guidelines have inserted these agents among the drugs of choice in the empirical therapy of LRTIs. This review discusses the most recent data on the bacteriological and clinical activity of the new fluoroquinolones and critically analyses the risks of a potential overuse of this valuable new class of drugs.

Microbiological rationale for the utilisation of prulifloxacin, a new fluoroquinolone, in the eradication of serious infections caused by Pseudomonas aeruginosa

Minimal inhibitory concentrations (MICs) of prulifloxacin were evaluated in comparison with ciprofloxacin, levofloxacin and moxifloxacin against a large collection (N = 300) of Pseudomonas aeruginosa strains characterised according to the CLSI/NCCLS microdilution method. Additional in vitro tests (time-kill curves and mutant prevention concentration (MPC) determinations) were carried out. Assuming a susceptibility breakpoint for prulifloxacin identical to that of ciprofloxacin, the new fluoroquinolone emerged as the most potent antibiotic (72% of susceptible strains versus 65%, 61% and 23% for ciprofloxacin, levofloxacin and moxifloxacin, respectively). Time-kill tests at 4x MIC confirmed the pronounced bactericidal potency of the drug against P. aeruginosa. Amongst the members of the fluoroquinolone class assessed, prulifloxacin produced the lowest MPC values (< or = 4 mg/L). Our in vitro results indicate that prulifloxacin represents the most powerful antipseudomonal drug available today.

Prulifloxacin versus ciprofloxacin in the treatment of adults with complicated urinary tract infections

INTRODUCTION

The present study was performed to evaluate the efficacy and safety of a 10-day regimen of prulifloxacin 600 mg once daily as compared to ciprofloxacin 500 mg twice daily in the treatment of patients with complicated urinary tract infections (UTIs).

MATERIALS AND METHODS

257 patients (mean age +/- SD 62.3 +/- 16.5) were enrolled and orally treated with prulifloxacin (127 patients) or ciprofloxacin (130 patients). The study was designed as a randomized, double-blind, double-dummy, controlled clinical trial. The primary efficacy parameter was the eradication of infecting strains (<10(3) cfu/ml). The clinical outcome and tolerability were also assessed.

RESULTS

At baseline, the most common infecting strains were Escherichia coli (62.8%), Proteus mirabilis (7.1%) and Klebsiella pneumoniae (4.1%). At the early follow-up, the rate of patients showing successful treatment was 90.8% in the prulifloxacin group, and 77.8% in the ciprofloxacin group (p = 0.008). A positive clinical outcome was observed in 94.8 and 93.3% of prulifloxacin- and ciprofloxacin-treated patients. Both drugs were well tolerated. Two patients dropped out for treatment-related adverse events.

CONCLUSIONS

The high urinary concentrations of prulifloxacin, combined with a broad-spectrum antimicrobial activity, allow its use in the empiric therapy of UTIs.

Interpretive criteria for disk diffusion susceptibility testing of ulifloxacin, the active metabolite of prulifloxacin

Prulifloxacin, a new fluoroquinolone, is a prodrug whose active compound, ulifloxacin, is derived from its transformation after oral administration and intestinal absorption. Based on early pharmacokinetic and pharmacodynamic data, the following MIC breakpoints have tentatively been proposed: < or = 1 microg/ml, susceptible; 2 microg/ml, intermediate; and > or = 4 microg/ml, resistant. In this report, ulifloxacin MIC vs. zone diameter scattergrams and discrepancy rates were analyzed in 461 freshly isolated clinical strains (237 Enterobacteriaceae, 101 nonfermenters, and 123 Gram-positive bacteria). In agreement with the guidelines of the National Committee for Clinical Laboratory Standards, a modification of the error rate-bounded method was used to select disk diffusion test breakpoints. The following zone diameter breakpoints were chosen and are proposed herein for the interpretation of ulifloxacin disk (5 microg) test results: < or = 15 and > or = 19 mm for Enterobacteriaceae, < or = 16 and > or = 20 mm for nonfermenters, and < or = 14 and > or = 18 mm for Gram-positive bacteria. By applying these breakpoint values, no very major errors were detected, while major and minor errors were largely below the accepted discrepancy rates.

Penetration of Orally Administered Prulifloxacin Into Human Lung Tissue

OBJECTIVE

To evaluate the distribution in lung tissue of ulifloxacin, the active metabolite of prulifloxacin, a new once-daily fluoroquinolone administered orally in a single 600mg dose.

DESIGN

Open-label, randomised study.

PATIENTS

Twenty-seven patients (25 males, 2 females; mean age 65.7 years [range 49-79 years]) with a lung neoplasm requiring lobectomy or pneumonectomy.

METHODS

Patients were randomly assigned to five treatment groups and received a single oral dose of prulifloxacin 600mg at 2, 4, 6, 12 or 24 hours preoperatively. During surgery, blood and healthy lung (based on macroscopic appearance) samples were collected at the same time. Ulifloxacin concentrations in plasma and lung tissue were determined by a validated reversed-phase high-performance liquid chromatography assay. Lung tissue ulifloxacin concentrations were adjusted for blood contamination, by measuring haemoglobin in the supernatant of each tissue sample and applying a corrective equation.

RESULTS

Ulifloxacin concentration in lung tissue exceeded plasma concentration at every timepoint. Following administration of prulifloxacin 600mg, the overall mean corrected lung/plasma ratio over the 24-hour period was 6.9 (range 1.2-14.1). When sampling intervals were assessed, the corrected lung/plasma ratios were 7.5 (2 hours after dosing), 6.3 (4 hours), 4.3 (6 hours), 7.0 (12 hours) and 9.2 (24 hours). The mean corrected lung/plasma area under the concentration-time curve ratio was 6.3, demonstrating the ability of the drug to penetrate lung tissue and confirming the high exposure of this target tissue to ulifloxacin. However, the limitation of the lung tissue sampling method and the high interpatient variability should be considered. Over the 24-hour period, the concentrations of ulifloxacin in lung tissue were higher than the minimum inhibitory concentration (MIC) values for pathogens frequently involved in community-acquired respiratory tract infections.

CONCLUSION

Lung tissue penetration data may have a supportive value when considered jointly with MICs and efficacy results. The findings from this lung penetration study could explain the efficacy of once-daily prulifloxacin 600mg observed in clinical trials conducted in patients with exacerbation of chronic bronchitis.

Molecular Characterization of Clinical Streptococcus pneumoniae Isolates with Reduced Susceptibility to Fluoroquinolones Emerging in Italy

Fifteen Streptococcus pneumoniae clinical isolates with reduced fluoroquinolone susceptibility (defined as a ciprofloxacin MIC of > or = 4 microg/ml), all collected in Italy in 2000-2003, were typed and subjected to extensive molecular characterization to define the contribution of drug target alterations and efflux mechanisms to their resistance. Serotyping and pulsed-field gel electrophoresis analysis indicated substantial genetic unrelatedness among the 15 isolates, suggesting that the new resistance traits arise in multiple indigenous strains rather than through clonal dissemination. Sequencing of the quinolone resistance-determining regions of gyrA, gyrB, parC, and parE demonstrated that point mutations producing single amino acid changes were more frequent in topoisomerase IV (parC mutations in 14 isolates and parE mutations in 13) than in DNA gyrase subunits (gyrA mutations in 7 isolates and no gyrB mutations observed). No isolate displayed a quinolone efflux system susceptible to carbonyl cyanide m-chlorophenylhydrazone; conversely, four-fold or greater MIC reductions in the presence of reserpine were observed in all 15 isolates with ethidium bromide, in 13 with ulifloxacin, in 9 with ciprofloxacin, in 5 with norfloxacin, and in none with five other fluoroquinolones. The effect of efflux pump activity on the level and profile of fluoroquinolone resistance in our strains was minor compared with that of target site modifications. DNA mutations and/or efflux systems other than those established so far might contribute to the fluoroquinolone resistance expressed by our strains. Susceptibility profiles to nonquinolone class antibiotics and resistance-associated phenotypic and genotypic characteristics were also determined and correlated with fluoroquinolone resistance. A unique penicillin-binding protein profile was observed in all five penicillin-resistant isolates, whereas the same PBP profile as S. pneumoniae R6 was exhibited by all six penicillin-susceptible isolates. This is the first attempt to molecularly characterize clinical isolates of S. pneumoniae with reduced susceptibility to fluoroquinolones emerging in Italy.

Prulifloxacin: in vitro (HERG current) and in vivo (conscious dog) assessment of cardiac risk

Prulifloxacin, a new thiazeto-quinoline derivative with antibiotic properties, was evaluated for cardiac risk both in vitro on the ether-à-go-go-related gene (HERG) K+ channel, and in vivo in the conscious dog monitored by telemetry. HERG current was measured from stably transfected human embryonic kidney (HEK) 293 cells by means of the patch-clamp technique. Application of AF 3013, the active metabolite of prulifloxacin, produced only minor reduction of HERG current amplitude (tail current=-40 mV), producing a maximum blockade of 12.3 +/- 3.3% at the highest concentration tested (335 microM). In comparison, ciprofloxacin also failed to produce a 50% inhibition of HERG current amplitude, although the maximum blockade was greater than that observed with prulifloxacin (47.6 +/- 1.9% at the highest concentration tested (335 microM). In contrast, moxifloxacin blocked HERG current amplitude with an IC50 value of 74.7 microM. Prulifloxacin had no effect on the QTc interval (Fridericia's) following 5 days of repeated oral administration (150 mg/kg/day) in the conscious dog monitored by telemetry. These findings suggest that prulifloxacin is not likely to prolong the QT interval.

Prulifloxacin

Prulifloxacin, the prodrug of ulifloxacin, is a broad-spectrum oral fluoroquinolone antibacterial agent. After absorption, prulifloxacin is metabolised by esterases to ulifloxacin. The drug has a long elimination half-life, allowing once-daily administration. Ulifloxacin is generally more active in vitro than other fluoroquinolones against a variety of clinical isolates of Gram-negative bacteria, including community and nosocomial isolates of Escherichia coli, Klebsiella spp., Proteus, Providencia and Morganella spp., Moraxella catarrhalis and Haemophilus spp. The activity of ulifloxacin against Pseudomonas aeruginosa varies between countries. Gram-positive organisms, including meticillin- or oxacillin-susceptible Staphylococcus aureus, Enterococcus spp. and Italian community isolates of Streptococcus pneumoniae are susceptible to ulifloxacin. Activity against Spanish strains of S. pneumoniae is moderate. In well designed clinical trials, good clinical and bacteriological efficacy (similar to that of ciprofloxacin, amoxicillin/clavulanic acid or pefloxacin) was seen with prulifloxacin 600 mg once daily for 10 days in patients with acute exacerbations of chronic bronchitis or complicated lower urinary tract infections (UTIs), and with single-dose prulifloxacin 600 mg in acute, uncomplicated lower UTIs. Prulifloxacin was generally well tolerated in clinical trials, with a similar tolerability profile to that of ciprofloxacin.

Randomized, double-blind study of prulifloxacin versus ciprofloxacin in patients with acute exacerbations of chronic bronchitis

BACKGROUND

Recently the role of bacteria in acute exacerbations of chronic bronchitis (AECB) as well as antibiotic treatment with selected drugs, especially fluoroquinolones, have been better defined.

OBJECTIVE

To assess the efficacy and safety in patients with AECB of prulifloxacin in comparison with ciprofloxacin.

METHODS

AECB was defined according to the guidelines for the evaluation of new anti-infective drugs for the treatment of respiratory tract infections (1992). 235 patients took part in the trial; 117 (88 males and 29 females, mean age 64.8 years) received 600 mg prulifloxacin once daily and 118 (91 males and 27 females, mean age 64.5 years) 500 mg ciprofloxacin twice a day, for a duration of 10 days. The study design was randomized, multicenter, double-blind, double-dummy. Efficacy evaluations were performed by comparing pretreatment and posttreatment assessments. The clinical response was determined by 4-point rating scores on cough, dyspnea, and expectoration (volume and appearance). The microbiological response was assessed on sputum specimen.

RESULTS

Clinical success was observed in 84.7 and 85% of patients in the prulifloxacin and ciprofloxacin groups, respectively. The 95% confidence interval proved the equivalence of treatments. Both drugs successfully eradicated the most commonly isolated strains, including Haemophilus influenzae, Streptococcus pneumoniae, Klebsiella pneumoniae and Pseudomonas aeruginosa. Both treatments were well tolerated. Adverse drug reactions were always of mild or moderate intensity.

CONCLUSION

The study showed that a 10-day course of prulifloxacin is as effective and safe as ciprofloxacin in the treatment of patients with AECB.