Bacteriological Response Rates Research Articles

Evaluation of nephrotoxicity and prognosis in patients treated with colistin due to hospital-acquired pneumonia.

Colistimethate sodium (CMS) is frequently used in the treatment of nosocomial multidrug-resistant gram-negative infections. Nephrotoxicity is the most important side effect. The aim of this study is to evaluate the effect of colistin on nephrotoxicity and to assess prognosis in patients treated with CMS due to hospital-acquired pneumonia (HAP). Patients treated with CMS for HAP due to multidrug-resistant Pseudomonas aeruginosa or Acinetobacter baumannii were included in this cohort study. We evaluated 281 patients treated with two different brands of CMS whose administration dose is different: imported (n= 58, low dose/kg) and domestic (n= 223, high dose/kg). Nephrotoxicity developed in 175 patients (62.3%). The median age (73 vs. 66 years, p= 0.004) and mortality rates were higher (66.9% vs. 52.8%, p= 0.022) in patients having nephrotoxicity. The patients receiving high dose/kg had higher nephrotoxicity rate (67.7% vs. 41.4%, p< 0.001). The clinical, bacteriological response and mortality rates of the whole group were 52.0%, 61.0%, 61.6%, respectively. The clinical and bacteriological response rates were similar in the different dose groups. Multivariate analysis showed that nephrotoxicity was associated with domestic brand depending on use of high dose (OR= 3.97), advanced age (β= 0.29, p= 0.008), male gender (OR= 2.60), hypertension (OR= 2.50), red blood cells transfusion (OR= 2.54), absence of acute kidney injury (OR= 10.19), risk stage of RIFLE (OR= 11.9). Nephrotoxicity is associated with the use of high dose colistin, age, gender, hypertension, red blood cells replacement and RIFLE stage. The mortality rate is higher in patients developing nephrotoxicity.

Comparison of colistin and colistin/sulbactam for the treatment of multidrug resistant Acinetobacter baumannii ventilator-associated pneumonia

To compare clinical and microbiological efficacy of colistin and colistin/sulbactam for the treatment of multidrug-resistant (MDR) Acinetobacter baumannii VAP in intensive care units (ICUs). In this retrospective analysis, patients (>16 years-old) who received IV colistin or colistin/sulbactam for the treatment of MDR A. baumannii VAP were evaluated. The clinical and microbiological responses to therapies were assessed on the fifth day and at the end of the therapy. During the study period, 89 patients were enrolled into the study. Fifty-two (58.4 %) patients received colistin and 37 (41.6 %) patients received colistin/sulbactam therapy. The median APACHE II score was higher and diabetes mellitus was more common in the colistin/sulbactam group (p < 0.05). However, other demographic characteristics were not statistically significant between groups. On the fifth day of colistin and colistin/sulbactam therapies, clinical response rates were 40.4 and 43.2 %, respectively. At the end of the therapies, clinical response rates were 29.8 and 40 %, respectively. The bacteriological response rates were 72.3 and 85.7 % in colistin and colistin/sulbactam groups, respectively. There were no statistically significant differences in clinical cure rates or bacteriological clearance rates between the two groups. The colistin/sulbactam combination therapy is promising in severe MDR A. baumannii VAP. Although, the difference was not statistically significant, clinical cure rates or bacteriological clearance rates were better in the combination group than colistin monotherapy.

Update on the Efficacy and Tolerability of Meropenem in the Treatment of Serious Bacterial Infections

Meropenem is a carbapenem antibiotic approved by the US Food and Drug Administration for the treatment of complicated skin and skin-structure infections, complicated intra-abdominal infections, and pediatric bacterial meningitis (in patients >or=3 months of age). In clinical trials, it also has shown efficacy as initial empirical therapy for the treatment of nosocomial pneumonia. Unlike other beta-lactam antibiotics, including third-generation cephalosporins, carbapenems have shown activity against extended-spectrum beta-lactamase-producing and AmpC chromosomal beta-lactamase-producing bacteria. Compared with imipenem, meropenem is more active against gram-negative pathogens and somewhat less active against gram-positive pathogens, and it does not require coadministration of a renal dehydropeptidase inhibitor. In most comparative trials, clinical and bacteriological response rates with imipenem and meropenem were similar. Compared with clindamycin/tobramycin, meropenem is associated with a reduced length of hospital stay and a shorter duration of therapy among patients with complicated intra-abdominal infections. Meropenem is well tolerated by children and adults and has an acceptable safety profile. Alternative meropenem dosing strategies for the optimization of outcomes are under investigation.

Doripenem

Doripenem, a parenteral, broad-spectrum antibacterial agent of the carbapenem family, is indicated as empirical therapy in serious bacterial infections in adults. Doripenem is indicated in Japan for use as a single agent in intra-abdominal infections (IAIs), lower respiratory tract infections (including nosocomial pneumonia), complicated urinary tract infections (cUTIs) and a variety of other bacterial infections, such as complicated skin and skin structure infections (cSSSIs), obstetric and gynaecological infections, serious ear, nose and throat infections, sepsis and endocarditis, dental and oral surgical infection, and ophthalmic infection caused by various susceptible strains of Gram-negative, Gram-positive or anaerobic bacteria. Doripenem is indicated in the US for the treatment of complicated IAIs (cIAIs) or cUTIs, including pyelonephritis, caused by susceptible strains of designated pathogens, and in the EU for the treatment of nosocomial pneumonia (including ventilator-associated pneumonia [VAP]), cIAIs or cUTIs.Doripenem has a broad spectrum of in vitro activity against Gram-positive and Gram-negative bacteria, including extended-spectrum beta-lactamase (ESBL)- and AmpC-producing Enterobacteriaceae, and anaerobic pathogens. The drug also has a low propensity to select for resistance and is suitable for the prolonged infusions that may be required to achieve pharmacodynamic/pharmacokinetic targets for bactericidal activity (and therefore efficacy) against pathogens with increased MICs (minimum concentrations required to inhibit the pathogens). Doripenem is no less effective than other antibacterial agents, including meropenem, imipenem/cilastin, piperacillin/tazobactam or levofloxacin in a wide range of serious bacterial infections, such as complicated lower respiratory infections, nosocomial pneumonia (including VAP), cIAIs and cUTIs, and is well tolerated. Thus, doripenem is a valuable addition to the options available for the empirical treatment of serious bacterial infections in hospitalized patients.

Gemifloxacin once daily for 5 days versus 7 days for the treatment of community-acquired pneumonia: a randomized, multicentre, double-blind study

Short-course therapy has been advocated for the treatment of community-acquired pneumonia (CAP). We compared the efficacy and safety of 5 and 7 day courses of gemifloxacin for outpatient treatment of mild-moderate CAP. In a multicentre, double-blind, parallel group study, patients were randomized to receive 320 mg of oral gemifloxacin once daily for 5 or 7 days. Over 95% of all patients in each cohort had a Fine score of <or=III. The primary efficacy endpoint was clinical cure at follow-up (days 24-30). Secondary outcomes were clinical and bacteriological responses at the end of therapy (days 7-9) and bacteriological and radiological responses at follow-up. Adverse events (AEs) were also monitored. In a total of 469 per protocol (PP) patients, clinical resolution at follow-up was 95% and 92% for 5 and 7 day treatments, respectively [95% confidence interval (CI) -1.48, 7.42], indicating non-inferiority of 5 day treatment. Clinical resolution at the end of therapy was 96% for both regimens (95% CI -3.85, 3.42). Bacteriological response rates in PP patients at the end of therapy were 94% and 96% for 5 and 7 day groups, respectively (95% CI -8.27, 3.25) and 91% for both groups at follow-up (95% CI -6.89, 7.93). Radiological success in PP patients at follow-up was 98% and 93% in 5 and 7 day groups, respectively (95% CI 0.35, 7.91). Pre-therapy pathogens were identified in 242 (47.3%) patients, most commonly Streptococcus pneumoniae. Frequency of treatment-related AEs was 21% in both cohorts with discontinuation rates of 1.2% and 2% in the 5 and 7 day groups, respectively. A lower incidence of rash was observed in the 5 day cohort (0.4%) versus the 7 day cohort (2.8%) (P=0.04). Gemifloxacin once daily for 5 days is not inferior to 7 days in the PP population with respect to clinical, bacteriological and radiological efficacy. Further work is needed, however, to explore whether fewer treatment days would improve patient compliance and reduce the incidence of AEs.

The efficacy of cefditoren pivoxil in the treatment of lower respiratory tract infections, with a focus on the per-pathogen bacteriologic response in infections caused by Streptococcus pneumoniae and Haemophilus influenzae: A pooled analysis of seven clinical trials

Background: Community-acquired pneumonia (CAP) and acute exacerbations of chronic bronchitis (AECB) are frequently caused by Streptococcus pneumoniae, Haemopbilus influenzae, and Moraxella catarrbalis; thus, these are the target pathogens for antibiotic treatment. Objectives: This pooled analysis was performed to evaluate the efficacy of cefditoren pivoxil (CDN) in patients with lower respiratory tract infections (CAP or AECB). A particular focus was the per-pathogen bacteriologic response rate among the most common causative pathogens, S pneumoniae, H influenzae, and M catarrbalis. Methods: The final reports of all clinical trials of CDN in the treatment of community-acquired lower respiratory tract infection were reviewed. Microbiologic outcome data for CDN 200 and 400 mg and comparator treatments were pooled from 4 CAP studies (3 randomized and 1 noncomparative) and 3 AECB studies. The comparators were the standard oral treatments clarithromycin 500 mg BID, cefuroxime 250 mg BID, cefpodoxime 200 mg BID, and amoxicillin/clavulanate 500/125 mg TID or 875/125 mg BID. Microbiologic response was defined as eradication of the initial pathogen or presumed eradication (absence of sputum for culture in a patient with a clinical response). Results: The bacteriologically evaluable population contained 654 patients in the CDN 200-mg group, 592 in the CDN 400-mg group, and 664 in the comparator group. A total of 1223 target pathogens were isolated before treatment: 406 isolates of S pneumoniae (including 56 penicillin-nonsusceptible [intermediate + resistant] strains), 595 isolates of H influenzae, and 222 isolates of M catarrbalis. The microbiologic response ranged from 84.1% to 88.8% in the CAP studies and from 75.1% to 77.1% in the AECB studies, with no differences between the CDN 200-mg, CDN 400-mg, and comparator groups. In the analysis of per-pathogen bacteriologic response, similar response rates were found for S pneumoniae (range, 88.5%–92.0%), H influenzae (range, 82.7%–86.6%), and M catarrbalis (range, 84.1%–95.2%), with no significant differences between groups. Focusing on penicillin-nonsusceptible (MIC ≥0.12 μg/mL) strains of S pneumoniae, CDN (both doses pooled) was associated with a response rate of 92.3% (36/39 isolates); all nonresponders were in the CDN 200-mg group. When only penicillin-resistant (MIC ≥2 μg/mL) strains were considered, there was only 1 nonresponder, again in the CDN 200-mg group. Thus, the overall response rate to CDN (both doses pooled) was 94.4% (17/18 isolates). Conclusions: In this pooled analysis, CDN was associated with high rates of per-pathogen bacteriologic response among the main causative pathogens in lower respiratory tract infection. The rates of response were ≈85% against H influenzae and ≈90% against S pneumoniae, including penicillin-intermediate and penicillin-resistant strains.

Once daily clarithromycin extended-release vs twice-daily amoxicillin/clavulanate in patients with acute bacterial sinusitis: a randomized, investigator-blinded study

ABSTRACTObjective: To compare the efficacy and tolerability of clarithromycin extended-release (ER) to amoxicillin/clavulanate in patients diagnosed with acute bacterial sinusitis.Research design and methods: In a controlled, multicenter, investigator-blinded study, 437 ambulatory patients at least 12 years old with signs/symptoms and radiographic findings of acute sinusitis were randomized to receive clarithromycin ER 1000 mg once daily or amoxicillin/clavulanate 875 mg/125 mg twice daily for 14 days.Main outcome measures: Clinical and bacteriological response rates were determined at a test-of-cure visit, which was conducted up to 10 days following the completion of treatment. Radiological response was assessed at a follow-up visit.Results: The clinical cure rate in clinically evaluable patients was 98% (184/188) in the clarithromycin ER group and 97% (179/185) in the amoxicillin/clavulanate group (95% CI for the difference in rates [–2.4%, 4.7%]). Clinical cure was sustained at the follow-up visit (96% for each treatment group). The pathogen eradication rates were 94% (61/65) in the clarithromycin ER group and 98% (61/62) in the amoxicillin/clavulanate group (95% CI for difference in rates [–12.0%, 2.9%]). The radiological success rate was 94% (172/183) in both the clarithromycin ER and amoxicillin/clavulanate groups (95% CI for difference in rates [–4.9%, 4.9%]). Symptomatic improvement or relief was observed as early as 2 days–5 days after the initiation of study drug, with a statistically significantly higher resolution rate of sinus pressure ( p = 0.027) and improvement/resolution rate of nasal congestion ( p = 0.035) during treatment with clarithromycin ER. The resolution/improvement rate at the test-of-cure visit for each treatment group was ≥ 94% for the primary acute sinusitis signs/symptoms, with a statistically significantly higher resolution/improvement rate of purulent nasal discharge with clarithromycin ER ( p = 0.010). Both study drugs had a positive and rapid impact on quality of life. Patients reported a high level of satisfaction and probability of using either study antibiotic again, and health care resource use was low, with slightly fewer sinusitis-related physician and outpatient visits required by patients in the clarithromycin ER group ( p = 0.055). The treatment groups were comparable with respect to incidence of drug-related adverse events.Conclusion: In this multinational population of patients with acute bacterial sinusitis, clarithromycin ER was comparable, and for selected measures superior, to amoxicillin/clavulanate based on clinical, bacteriological, and radiological responses as well as quality of life measures, satisfaction with antibiotic therapy, and health care resource utilization.

Gemifloxacin once daily for 7 days compared to amoxicillin/clavulanic acid thrice daily for 10 days for the treatment of community-acquired pneumonia of suspected pneumococcal origin

Context: Community-acquired pneumonia (CAP) is common among adults and contributes considerably to morbidity and mortality. Objective: To compare the safety and efficacy of gemifloxacin to high-dose amoxicillin/clavulanate for the treatment of CAP of suspected pneumococcal origin. Design: Randomized, multicentre, double-blind, double-dummy, parallel group Phase III study. Setting and participants: From September 1998 to July 1999, 324 patients with CAP were randomized at 102 centers in France, Poland and the Republic of South Africa. Intervention: Patients were double-blind randomized to receive either oral gemifloxacin 320 mg once daily for 7 days or oral amoxicillin/clavulanate 1 g/125 mg three times daily for 10 days. Main outcome measures: The main outcome measures were clinical, bacteriological, and radiological responses at the end of therapy (day 12–14) and follow-up (day 24–30) visits. Results: In 228 PP patients, clinical resolution at follow-up was 88.7% for 7-day gemifloxacin and 87.6% for 10-day amoxicillin/clavulanate [95% CI, −7.3, 9.5]. In 249 PP patients, clinical resolution at end of therapy was 95.3% for 7-day gemifloxacin vs. 90.1% for 10-day amoxicillin/clavulanate [95% CI, −1.2, 11.7]. Bacteriologic response rates for the PP patients at end of therapy were 96.3% for 7-day gemifloxacin and 91.8% for the amoxicillin/clavulanate group [95% CI, −4.7, 13.6]. Bacteriologic response rates at follow-up were 87.2% for 7-day gemifloxacin and 89.1% for the amoxicillin/clavulanate group [95% CI, −15.0, 11.2]. Specifically gemifloxacin eradicated 95.7% of Streptococcus pneumoniae including penicillin and macrolide resistant strains. Radiological response rates for the PP patients at end of therapy were 89.1% for 7-day gemifloxacin and 87.6% for the amoxicillin/clavulanate group. The most frequently reported drug-related events were in the gemifloxacin group, diarrhea (6.0%) and rash (3.0%) and in the amoxicillin/clavulanate group, diarrhea (11.1%) and fungal infection, vaginitis and vomiting (each 2.0%). Overall there were statistically fewer withdrawals due to lack of therapeutic effect in the gemifloxacin group compared with the amoxicillin/clavulanate cohort, (95% CI, −8.8;0.6; P=0.03). Conclusion: Gemifloxacin 320 mg once daily for 7 days was found to be clinically, bacteriologically, and radiologically as effective as 10 days of amoxicillin/clavulanate 1 g/125 mg three times daily for the treatment of suspected pneumococcal CAP.

A randomised, double-blind, double-dummy comparative study of gatifloxacin with clarithromycin in the treatment of community-acquired pneumonia

Eligible patients were randomised in this multicentre, randomised, double-blind, double-dummy parallel-group study in a ratio of 1:1 to either gatifloxacin 400 mg once-daily for 5-14 days plus matching placebo, or clarithromycin 500 mg twice-daily for 5-14 days. The primary outcome measure was clinical response (clinical cure plus improvement) at the end of treatment. Secondary endpoints were clinical response at end of study, clinical cure at end of treatment and end of study, bacteriological response at end of treatment and end of study, and treatment duration. The overall clinical response was similar in the two treatment groups, with 92.2% of gatifloxacin-treated patients cured or improved at the end of treatment, compared with 93.1% of those receiving clarithromycin. Corresponding bacteriological response rates (eradication plus presumed eradication) were 96.7% and 87.5%, respectively. The study drugs were well-tolerated, with nausea (gatifloxacin) and bitter taste (clarithromycin) being the only treatment-related adverse events with a frequency of > 5%. No patients experienced phototoxicity, hepatic or renal dysfunction, tendonitis or crystalluria. Oral gatifloxacin 400 mg once-daily appeared to be a safe and effective alternative to clarithromycin in the treatment of community-acquired pneumonia.

Gatifloxacin 200 mg or 400 mg once daily is as effective as ciprofloxacin 500 mg twice daily for the treatment of patients with acute pyelonephritis or complicated urinary tract infections

The efficacy and safety of two oral dosing regimens of gatifloxacin were compared to ciprofloxacin in the treatment of complicated urinary tract infection in a randomised, double-blind multi-centre trial. One thousand one hundred and twenty-three adult patients with complicated urinary tract infection (70%) or pyelonephritis (30%) were initially enrolled, 1122 were treated. Of these, 824 were included in a modified ITT population: gatifloxacin 200 mg (274 patients) or 400 mg (280 patients) once daily or ciprofloxacin 500 mg twice daily for 5–14 days (269 patients). Bacteriological and clinical responses were assessed 7–9 days after the end of treatment (EOT) and 4–6 weeks post-treatment (end of study visit, EOS). The bacteriological response rates per patient at EOT in the gatifloxacin 400 mg, gatifloxacin 200 mg and ciprofloxacin groups were 77% (207/269), 78% (208/268) and 73% (190/259), respectively. At EOS they were slightly lower: 70% (184/262), 71% (176/248) and 69% (174/252), respectively. The clinical responses at EOT were 69% (190/277), 70% (190/273) and 65% (174/266). At EOS they were 71% (193/273), 70% (182/259) and 74% (190/258). The overall eradication rates of initial pathogens at EOT and EOS were 85.3% and 88.4% in the gatifloxacin 400 mg group; 84.1 and 90.1% in the gatifloxacin 200 mg group and 85.1 and 91.4% in the ciprofloxacin group. Both oral regimens of gatifloxacin were as effective as that of ciprofloxacin. All treatment groups showed a similar safety profile, nausea being the most frequently reported adverse event.

A Comparison of the Efficacy of Telithromycin versus Cefuroxime Axetil in the Treatment of Acute Bacterial Maxillary Sinusitis

Telithromycin, a new ketolide, exhibits potent activity against respiratory pathogens, including resistant strains. Five days of telithromycin (800 mg once daily) was compared with 10 days of cefuroxime axetil (250 mg twice daily) in subjects (n = 593) with acute bacterial maxillary sinusitis (ABMS). Bacteriologic sampling was accomplished by sinus puncture or nasal endoscopy. The primary efficacy variable was clinical outcome at the posttherapy/test-of-cure evaluation in clinically evaluable patients. Clinical cure was achieved in 85.2% of telithromycin patients and 82.0% of cefuroxime axetil patients (difference in proportions, 3.2%; 95% confidence interval, -7.1-13.4%). Satisfactory bacteriologic response rates were comparable. Treatment-emergent adverse events for both drugs were mild or moderate. The most frequently reported treatment-emergent adverse events were nausea and diarrhea. Once-daily telithromycin for 5 days was equivalent in efficacy to twice-daily cefuroxime axetil for 10 days in patients with ABMS. Telithromycin is a suitable option for short-course therapy of ABMS.

Levofloxacin

Levofloxacin (Levaquin) is a fluoroquinolone antibacterial agent with a broad spectrum of activity against Gram-positive and Gram-negative bacteria and atypical respiratory pathogens. It is active against both penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae. The prevalence of S. pneumoniae resistance to levofloxacin is <1% overall in the US.A number of randomised comparative trials in the US have demonstrated the efficacy of levofloxacin in the treatment of infections of the respiratory tract, genitourinary tract, skin and skin structures. Sequential intravenous to oral levofloxacin 750mg once daily for 7-14 days was as effective in the treatment of nosocomial pneumonia as intravenous imipenem/cilastatin 500-1000mg every 6-8 hours followed by oral ciprofloxacin 750mg twice daily in one study. In patients with mild to severe community-acquired pneumonia (CAP), intravenous and/or oral levofloxacin 500mg once daily for 7-14 days achieved clinical and bacteriological response rates similar to those with comparator agents, including amoxicillin/clavulanic acid, clarithromycin, azithromycin, ceftriaxone and/or cefuroxime axetil and gatifloxacin. A recent study indicates that intravenous or oral levofloxacin 750mg once daily for 5 days is as effective as 500mg once daily for 10 days, in the treatment of mild to severe CAP. Exacerbations of chronic bronchitis and acute maxillary sinusitis respond well to treatment with oral levofloxacin 500mg once daily for 7 and 10-14 days, respectively. Oral levofloxacin was as effective as ofloxacin in uncomplicated urinary tract infections and ciprofloxacin or lomefloxacin in complicated urinary tract infections. In men with chronic bacterial prostatitis treated for 28 days, oral levofloxacin 500mg once daily achieved similar clinical and bacteriological response rates to oral ciprofloxacin 500mg twice daily. Uncomplicated skin infections responded well to oral levofloxacin 500mg once daily for 7-10 days, while in complicated skin infections intravenous and/or oral levofloxacin 750mg for 7-14 days was at least as effective as intravenous ticarcillin/clavulanic acid (+/- switch to oral amoxicillin/clavulanic acid) administered for the same duration. Levofloxacin is generally well tolerated, with the most frequently reported adverse events being nausea and diarrhoea; in comparison with some other quinolones it has a low photosensitising potential and clinically significant cardiac and hepatic adverse events are rare. Levofloxacin is a broad-spectrum antibacterial agent with activity against a range of Gram-positive and Gram-negative bacteria and atypical organisms. It provides clinical and bacteriological efficacy in a range of infections, including those caused by both penicillin-susceptible and -resistant strains of S. pneumoniae. Levofloxacin is well tolerated, and is associated with few of the phototoxic, cardiac or hepatic adverse events seen with some other quinolones. It also has a pharmacokinetic profile that is compatible with once-daily administration and allows for sequential intravenous to oral therapy. The recent approvals in the US for use in the treatment of nosocomial pneumonia and chronic bacterial prostatitis, and the introduction of a short-course, high-dose regimen for use in CAP, further extend the role of levofloxacin in treating bacterial infections.

A comparison of gemifloxacin and clarithromycin in acute exacerbations of chronic bronchitis and long-term clinical outcomes

Background: Gemifloxacin is an enhanced-affinity quinolone with potent activity against lower respiratory tract pathogens. Objective: The efficacy and safety of a 5-day course of gemifloxacin were compared with those of a standard 7-day regimen of clarithromycin in patients with an acute exacerbation of chronic bronchitis (AECB). The impact of treatment on the long-term (26 weeks) clinical outcome was also assessed. Methods: The acute phase of this randomized, double-blind study was performed in 93 centers in 7 countries. Adult patients (age >40 years) with a history of chronic bronchitis and an Anthonisen type 1 acute exacerbation (increased dyspnea, cough, and sputum purulence) were eligible. Patients receiving systemic steroids at a dose of >10 mg prednisone or the equivalent were excluded. Patients were randomized to receive gemifloxacin 320 mg once daily for 5 days or clarithromycin 500 mg twice daily for 7 days. Clinical and bacteriologic response rates were assessed at the end-of-therapy visit (days 8–12), the week 2–3 follow-up visit (days 13–24), and the week 4–5 follow-up visit (days 25–38). The long-term phase (26 weeks), which included US and Canadian participants only, evaluated the proportion of patients who remained free of a recurrence of AECB requiring additional antimicrobial therapy after resolution of the initial episode. Results: Seven hundred twelve patients were randomized to treatment, 351 to gemifloxacin and 361 to clarithromycin. The long-term study included 438 patients, 214 receiving gemifloxacin and 224 receiving clarithromycin. Clinical success rates at the 2–3 week follow-up visit were 85.4% for gemifloxacin and 84.6% for clarithromycin. Bacteriologic success rates were 86.7% for gemifloxacin and 73.1% for clarithromycin. Significantly more patients receiving gemifloxacin than clarithromycin remained free of AECB recurrences (71.0% vs 58.5%, respectively; P = 0.016). Both treatments were well tolerated. Conclusions: In the acute treatment of Anthonisen type 1 AECB, a 5-day course of gemifloxacin was at least as effective as a 7-day regimen of clarithromycin. In this population, significantly more patients receiving gemifloxacin remained free of AECB recurrence after 26 weeks compared with those receiving clarithromycin.

Levofloxacin: an updated review of its use in the treatment of bacterial infections.

Levofloxacin is the L-form of the fluoroquinolone antibacterial agent, ofloxacin. In in vitro studies, levofloxacin demonstrated a broad range of activity against Gram-positive and -negative organisms and anaerobes. The drug is more active against Gram-positive organisms than ciprofloxacin, but less active than newer fluoroquinolones such as gatifloxacin. Its activity against Streptococcus pneumoniae is unaffected by the presence of penicillin resistance. In several randomised controlled trails, 5 to 14 days' treatment with intravenous and/or oral levofloxacin proved an effective therapy for upper and lower respiratory tract infections. In patients with mild to severe community-acquired pneumonia (CAP), intravenous and/or oral levofloxacin 500mg once or twice daily was as effective as intravenous and/or oral gatifloxacin, clarithromycin, azithromycin or amoxicillin/clavulanic acid. Overall, clinical response rates with levofloxacin ranged from 86 to 95% versus 88 to 96% with comparator agents; bacteriological response rates were 88 to 95% and 86 to 98%, respectively. Sequential (intravenous +/- oral switch) therapy with levofloxacin 750mg once daily was as effective as intravenous imipenem/cilastatin (+/- oral switch to ciprofloxacin) in patients with severe nosocomial pneumonia. Generally, oral levofloxacin 250 or 500mg once daily was at least as effective as oral cefaclor, cefuroxime axetil, clarithromycin or moxifloxacin in patients with acute exacerbations of chronic bronchitis as assessed by either clinical or bacteriological response rates. This approach also provided similar efficacy to amoxicillin/ clavulanic acid or clarithromycin in patients with acute sinusitis. Sequential therapy with levofloxacin 500mg twice daily for 7 to 14 days' was as effective as intravenous imipenem/cilastatin in patients with suspected bacteraemia. Oral levofloxacin 500mg once daily for 7 to 10 days was also an effective treatment in patients with uncomplicated skin and skin structure infections, and in those with complicated urinary tract infections. A higher dosage of sequential levofloxacin 750mg once daily proved as effective as intravenous ticarcillin/clavulanic acid (+/- oral switch to amoxicillin/clavulanic acid) in the treatment of complicated skin and skin structure infections. Pharmacoeconomic studies suggest that levofloxacin may be cost-saving in comparison to conventional therapies. Levofloxacin continues to demonstrate good clinical efficacy in the treatment of a range of infections, including those in which S. pneumoniae is a potential pathogen. Importantly, it has efficacy in CAP similar to that of gatifloxacin and at least as good as that of the third generation cephalosporins. Extensive clinical data confirm the good tolerability profile of this agent without the phototoxicity, hepatic and cardiac events evident with some of the other newer fluoroquinolone agents. Levofloxacin therefore offers a unique combination of documented efficacy and tolerability, and provides an important option for the treatment of bacterial infections.

Comparison of isepamicin with amikacin for the empirical treatment of febrile neutropenic children with malignancies

The efficacy and safety of isepamicin at 7.5 mg/kg i.v. q 12 h was prospectively compared with that of amikacin at the same dose for the treatment of febrile neutropenic children with malignancies. Thirty-nine patients were enrolled in the study; 25 received isepamicin and 14 amikacin. Clinical and bacteriological response rates were 100% for both groups. No adverse events occurred. Median peak serum levels were 19.7 mg/l for isepamicin and 19.20 mg/l for amikacin. Median trough serum levels were 0.72 mg/l for isepamicin and 0.68 mg/l for amikacin. It was concluded that isepamicin was as effective and safe as amikacin for the treatment of febrile neutropenic children with malignancies, and might be used in areas where resistance to other aminoglycosides is a problem.

Meropenem versus imipenem/cilastatin as empirical monotherapy for serious bacterial infections in the intensive care unit

To compare the efficacy and tolerability of meropenem and imipenem/cilastatin as empirical monotherapy in intensive care unit (ICU) patients with serious bacterial infections. A multicenter, open-label, randomized, parallel-group trial was conducted in Belgium, evaluating empirical monotherapy with meropenem or imipenem/cilastatin (both 1 g/8 h intravenously) in ICU patients with one or more of the following infections caused by sensitive pathogens: lower respiratory tract infection (LRTI) in ventilated patients, intra-abdominal infection or sepsis. The overall satisfactory clinical response rate at the end of randomized treatment was 77.0% (67/87) with meropenem and 68.1% (62/91) with imipenem/cilastatin (difference 8.9%; 95% confidence interval -4.2% to 21.9%; P = 0.185). The two drugs produced similar satisfactory clinical response rates against LRTIs: 68.3% (41/60) with meropenem versus 68.6% (35/51) with imipenem/cilastatin. Meropenem appeared to be slightly more effective against intra-abdominal infections: 95.5% (21/22) versus 76.7% (23/30), respectively. All five meropenem recipients with sepsis had a satisfactory clinical response, compared to 40.0% (4/10) of those who received imipenem/cilastatin. The overall satisfactory bacteriologic response rate was 67.1% (49/73) with meropenem and 60.3% (44/73) with imipenem/cilastatin (difference 6.9%; 95% confidence interval -8.7% to 22.4%; P = 0.389). The predominant pathogens were Escherichia coli, Enterobacter spp. and Pseudomonas aeruginosa. No incidences of drug-related nausea and vomiting were reported, but one probable drug-related seizure occurred in the imipenem/cilastatin group. Meropenem is at least as efficacious (clinically and bacteriologically) as imipenem/cilastatin for the empirical monotherapy of serious bacterial infections in ICU patients, and it can therefore be considered a useful option in this setting. Moreover, meropenem is well tolerated and offers several potential advantages, including greater in vitro activity against Gram-negative pathogens and the option of bolus administration.

Isepamicin versus amikacin for the treatment of acute pyelonephritis in children

In this study we compared the efficacy and safety of isepamicin versus amikacin at a dose of 7.5 mg/kg i.v. q12h for 10–14 days in children with pyelonephritis. Sixteen children were enrolled in the study; ten received isepamicin and six amikacin. Urine cultures grew Escherichia coli in all patients. All patients were treated successfully with either isepamicin or amikacin. Clinical and bacteriological response rates were 100% for both groups. No adverse events occurred. Peak serum levels ranged from 9.05 to 30.70 mg/l (median: 16.165) and from 12.20 to 25.90 mg/l (median: 19.05) for isepamicin and amikacin, respectively. Trough serum levels ranged from 0.11 to 3.20 mg/l (median: 0.75) and from 0.1 to 2.1 mg/l (median: 0.655), respectively. Isepamicin was shown to be as effective and safe as amikacin in the treatment of children with pyelonephritis and might prove an advantageous alternative in areas with high incidence of resistance to other aminoglycosides.

Treating acute bacterial exacerbations of chronic bronchitis in patients unresponsive to previous therapy: Sparfloxacin versus clarithromycin

The optimal antibiotic therapy for patients with acute bacterial exacerbations of chronic bronchitis (ABECB) who have failed to respond to previous oral antimicrobial therapy is not known; however, newer macrolide and fluoroquinolone antibiotics may be appropriate. This multicenter, randomized, double-masked, double-dummy study was undertaken to compare the efficacy and tolerability of sparfloxacin with those of clarithromycin in the treatment of ABECB. In 43 centers in the United States, 298 patients (52% male; age range, 19 to 92 years) were randomly allocated to receive a 400-mg loading dose of sparfloxacin, followed by 200 mg once daily, or clarithromycin 500 mg twice daily, for a total of 10 days. Signs and symptoms of ABECB were assessed at each of 4 visits, including a follow-up visit approximately 1 month after the completion of therapy. Efficacy was determined on the basis of the clinical and bacteriologic response rates in the clinically assessable population. Tolerability was assessed on the basis of patient reports, clinical evaluations, and laboratory tests. Of the 266 clinically assessable patients, 109 (85.2%) of 128 patients receiving sparfloxacin and 115 (83.3%) of 138 patients receiving clarithromycin had a clinically successful outcome (cure or improvement). The bacteriologic success rate (eradication of pathogen) was 88.9% (64 of 72 isolates) in the sparfloxacin group and 84.7% (83 of 98 isolates) in the clarithromycin group. Adverse events possibly or probably related to study drug included photosensitivity in 12 (8.3%) and rash in 6 (4.1%) of 145 patients in the sparfloxacin group, and diarrhea in 10 (6.5%), taste perversion in 9 (5.9%), and nausea in 8 (5.2%) of 153 patients in the clarithromycin group. Thus sparfloxacin was as well tolerated and as effective as clarithromycin in the treatment of patients with ABECB unresponsive to previous oral antimicrobial therapy. The overall rate of adverse events was comparable for the 2 study drags, but the types of events differed.

Intravenous azithromycin.

To review the pharmacology, microbiology, chemistry, pharmacokinetics, efficacy, safety, tolerability, dosage, administration, and economic issues of intravenous azithromycin. A MEDLINE search from 1978 to May 1998 of the English-language literature and an extensive review of journals and meeting abstracts was conducted. Due to the lack of published literature concerning the efficacy, safety, and pharmacokinetics of the intravenous formulation of azithromycin, the manufacturer was also contacted and requested to supply information concerning intravenous azithromycin. In vitro and preclinical studies were included, as well as data from Phase II and III clinical trials. Efficacy, pharmacokinetic, safety, and tolerability data were also supplemented with information from the manufacturer, due to the lack of published reports. Azithromycin, an azalide subclass of the macrolide antibiotics, is now available as an intravenous formulation. The intravenous form is approved for the treatment of community-acquired pneumonia caused by Chlamydia pneumoniae, Haemophilus influenzae. Legionella pneumophila, Moraxella catarrhalis, Mycoplasma pneumoniae, Staphylococcus aureus (methicillin-sensitive), and Streptococcus pneumoniae, and for the treatment of pelvic inflammatory disease caused by Chlamydia trachomatis, Neisseria gonorrhoeae, and Mycoplasma hominis in situations in which intravenous therapy is required. Its spectrum of activity, unique pharmacokinetics, and high and sustained tissue penetration allow for once-daily dosing with monotherapy in many cases. Clinical and bacteriologic response rates as well as the adverse event profile have been similar to or better than comparative agents. Azithromycin offers advantages over other agents due to its unique pharmacokinetics, high and sustained tissue penetration, and spectrum of activity. This allows for monotherapy and once-daily intravenous dosing for mild-to-moderate community-acquired pneumonia or pelvic inflammatory disease in many instances. Future research should focus on total duration of antibiotic therapy and the need, or lack thereof, for extensive oral antibiotic follow-up.

Piperacillin/tazobactam: an updated review of its use in the treatment of bacterial infections.

Piperacillin/tazobactam is a beta-lactam/beta-lactamase inhibitor combination with a broad spectrum of antibacterial activity encompassing most Gram-positive and Gram-negative aerobic bacteria and anaerobic bacteria, including many pathogens producing beta-lactamases. Evidence from clinical trials in adults has shown that piperacillin/tazobactam, administered in an 8:1 ratio, is an effective treatment for patients with lower respiratory tract, intra-abdominal, urinary tract, gynaecological and skin/soft tissue infections, and for fever in patients with neutropenia. Combination regimens of piperacillin/tazobactam plus an aminoglycoside are used to treat patients with severe nosocomial (hospital-acquired) infections. In clinical trials, piperacillin/tazobactam was significantly more effective than ticarcillin/clavulanic acid in terms of clinical and microbiological outcome in patients with community-acquired pneumonia. In patients with intra-abdominal infections, clinical and bacteriological response rates were significantly higher with piperacillin/tazobactam than with imipenem/cilastatin (administered at a dosage lower than is recommended in countries outside Scandinavia). Piperacillin/tazobactam in combination with amikacin was at least as effective as ceftazidime plus amikacin in the treatment of ventilator-associated pneumonia and was significantly more effective than ceftazidime plus amikacin in the empirical treatment of febrile episodes in patients with neutropenia or granulocytopenia. In other trials, the efficacy of piperacillin/tazobactam was similar to that of standard aminoglycoside-containing and other treatment regimens in patients with intra-abdominal, skin/soft tissue or gynaecological infections. Piperacillin/tazobactam is generally well tolerated. The most frequent adverse events are gastrointestinal symptoms (most commonly diarrhoea) and skin reactions. The incidence of adverse events with piperacillin/tazobactam is higher when the combination is given in combination with an aminoglycoside than when given as monotherapy. Because of the broad spectrum of antibacterial activity provided by piperacillin/tazobactam, it is useful for the treatment of patients with polymicrobial infections caused by aerobic or anaerobic beta-lactamase-producing bacteria. Piperacillin/tazobactam appears to have a particularly useful role in the treatment of patients with intra-abdominal infections and, in combination with amikacin, in the treatment of patients with febrile neutropenia, especially given the current prevalence of Gram-positive infections in this group.