A new therapeutic option for the treatment of pneumonia

Clostridium difficile infection following systemic antibiotic administration in randomised controlled trials: a systematic review and meta-analysis

Antibiotics have been the most important risk factor for Clostridium difficile infection (CDI). However, only data from non-randomised studies have been reviewed. We sought to evaluate the risk for development of CDI associated with the major antibiotic classes by analysing data from randomised controlled trials (RCTs). The PubMed, Cochrane and Scopus databases were searched and the references of selected RCTs were also hand-searched. Eligible studies should have compared only one antibiotic versus another administered systemically. Inclusion of studies comparing combinations of antibiotics was allowed only if the second antibiotic was the same or from the same class or if it was administered in a subset of the enrolled patients who were equally distributed in the two arms. Only a minority of the selected RCTs (79/1332; 5.9%) reported CDI episodes. Carbapenems were associated with more CDI episodes than fluoroquinolones [risk ratio (RR) = 2.44, 95% confidence interval (CI) 1.32-4.49] and cephalosporins (RR = 2.24, 95% CI 1.46-3.42), but not penicillins (RR = 2.53, 95% CI 0.87-7.41). Cephalosporins were associated with more CDIs than penicillins (RR = 2.36, 95% CI 1.32-4.23) and fluoroquinolones (RR = 2.84, 95% CI 1.60-5.06). There was no difference in CDI frequency between fluoroquinolones and penicillins (RR = 1.34, 95% CI 0.55-3.25). Finally, clindamycin was associated with more CDI episodes than cephalosporins and penicillins (RR = 3.92, 95% CI 1.15-13.43). In conclusion, data from RCTs showed that clindamycin and carbapenems were associated with more CDIs than other antibiotics.

Cefepime

Cefepime (Maxipime), Maxcef, Cepimax, Cepimex, Axepim, a parenteral fourth-generation cephalosporin, is active against many organisms causative in pneumonia. Cefepime has in vitro activity against Gram-positive organisms including Staphylococcus aureus and penicillin-sensitive, -intermediate and -resistant Streptococcus pneumoniae similar to that of cefotaxime and ceftriaxone. Cefepime also has good activity against Gram-negative organisms, including Pseudomonas aeruginosa, similar to that of ceftazidime. Importantly, cefepime is stable against many of the common plasmid- and chromosome-mediated beta-lactamases and is a poor inducer of AmpC beta-lactamases. As a result, it retains activity against Enterobacteriaceae that are resistant to third-generation cephalosporins, such as derepressed mutants of Enterobacter spp. Cefepime may be hydrolyzed by the extended-spectrum beta-lactamases produced by some members of the Enterobacteriaceae, but to a lesser extent than the third-generation cephalosporins. Monotherapy with cefepime 1 or 2g, usually administered intravenously twice daily, was as effective for clinical and bacteriological response as ceftazidime, ceftriaxone or cefotaxime monotherapy (1 or 2g two or three times daily) in a number of randomized, clinical trials in hospitalized adult, or less commonly, pediatric, patients with generally moderate to severe community-acquired or nosocomial pneumonia. More limited data indicated that monotherapy with cefepime 2g three times daily was also as effective in treating patients with nosocomial pneumonia as imipenem/cilostatin 0.5g four times daily, and when combined with amikacin, cefepime was as effective as ceftazidime plus amikacin. Patients with pneumonia who failed to respond to previous antibacterial therapy with penicillins or other cephalosporins responded to treatment with cefepime. Cefepime is generally well tolerated, with a tolerability profile similar to those of other parenteral cephalosporins. In clinical trials, the majority of adverse events experienced by cefepime recipients were mild to moderate and reversible. The most common adverse events with a causal relationship to cefepime reported in clinical trials included rash and diarrhea. Other, less common, adverse events included pruritus, urticaria, nausea, vomiting oral candidiasis, colitis, headache, fever, erythema and vaginitis.

CONCLUSION

Cefepime is an established and generally well tolerated parenteral drug with a broad spectrum of antibacterial activity which, when administered twice daily, provides coverage of most of the pathogens that may be causative in pneumonia. In randomized clinical trials in hospitalized patients with generally moderate to severe community-acquired or nosocomial pneumonia, cefepime monotherapy exhibited good clinical and bacteriological efficacy. Cefepime may become a preferred antibacterial agent for infections caused by Enterobacter spp. With prudent use in order to prevent the emergence of resistant organisms, cefepime will continue to be a suitable option for the empiric treatment of pneumonia.

Comparative study of the disposition of levofloxacin, netilmicin and cefepime in the isolated rat lung

An experimental model of artificially perfused and mechanically ventilated lung has been applied to compare the kinetic behaviour of levofloxacin, cefepime and netilmicin in this body tissue. The study has been performed to explore the usefulness of the isolated lung technique in the pharmacokinetic field, particularly to study the disposition of antibiotics in pulmonary tissue. The lung was perfused with Krebs-Henseleit medium containing 3% bovine albumin at a flow rate of 5 mL min−1. It was ventilated at 60 respirations/min with a 2-mL tidal volume of air previously humidified and warmed to 37°C. The concentrations of the above antibiotics were determined by HPLC techniques and the outflow curves were analysed by stochastic, as well as by model-dependent, methods. The results show pharmacokinetic differences among these antibiotics, which are in accordance with previously reported data, levofloxacin being the drug with the highest distribution coefficient in this tissue (1.25 ± 0.14 vs 0.39 ± 0.07 and 0.41 ± 0.06 mL g−1 for netilmicin and cefepime, respectively). Accordingly, the isolated lung of the rat, under the experimental conditions used here, constitutes an alternative model to be incorporated to pharmacokinetic studies with a great potential use for those drugs that show a pharmacological or toxicological action depending on the kinetic profile in the lung tissue.

In vitro activities of cefepime versus cefotaxime and ceftriaxone against penicillin-resistant Streptococcus pneumoniae determined by Etest

The Etest was used for determining in vitro susceptibilities of 144 unique clinical isolates of penicillin-intermediate and resistant Streptococcus pneumoniae to cefepime, cefotaxime, and ceftriaxone. MIC ranges were 0.12-8 mug/ml for cefepime and 0.06-16 mug/ml for cefotaxime and ceftriaxone. MICs for 50% of the isolates for the three agents were equivalent at 1 mug/ml, whereas MICs for 90% of the isolates were 2 mug/ml for cefotaxime and ceftriaxone, versus 4 mug/ml for cefepime. The Etest is a practical means for determining susceptibilities of S. pneumoniae to cefepime and other cephalosporins in diagnostic laboratories.

Efficacy and safety of cefepime: a systematic review and meta-analysis

Cefepime is a broad-spectrum cephalosporin with enhanced coverage against Gram-positive and Gram-negative bacteria. We did a systematic review of randomised trials that compared cefepime with another beta-lactam antibiotic, alone or with the addition of a non-beta-lactam antibiotic to both study groups. We searched Central, PubMed, Embase, Lilacs, new US Food and Drug Administration drug applications, conference proceedings, and references of the included studies. Two reviewers independently did the search and data extraction. 57 trials were included. All-cause mortality-the primary outcome-was higher with cefepime than other beta-lactams (risk ratio [RR] 1.26 [95% CI 1.08-1.49]). Sensitivity analyses by the trials' methodological quality revealed higher RRs for trials reporting adequate allocation-sequence generation (1.52 [1.20-1.92]) and allocation concealment (1.36 [1.09-1.70]). Baseline risk factors for mortality were similar. No significant differences between groups in treatment failure, superinfection, or adverse events were found. This Review provides evidence and offers possible explanations for increased mortality among patients treated with cefepime in randomised trials.

Cefepime versus ceftazidime for treatment of pneumonia

Consecutive patients with pneumonia, treated with cefepime (n = 66) or ceftazidime (n = 132), were evaluated in a retrospective, observational study. There was no significant difference between the two treatment groups with respect to age, underlying diseases, acute physical and chronic health evaluation score, intensive care unit admission, presence of sepsis, community or hospital acquisition, causative organism, duration of therapy, death, cure or improvement in infection, adverse events, superinfections, presence of vancomycin-resistant enterococcus (VRE) and resistance to therapy. Post-therapy hospitalization (days) and vancomycin co-administration were significantly lower, and time to vancomycin initiation significantly higher, in the cefepime compared with the ceftazidime group. The results suggest a trend towards less resistance on therapy, less VRE, reduced vancomycin use and shorter post-therapy hospitalization in patients treated with cefepime compared with ceftazidime. The clinical outcomes for hospitalized patients treated for serious pneumonia were similar between the two groups.

The Cost of Enhanced Acid Suppression

Peptic ulcer disease (PUD), gastroesophageal reflux disease (GERD), and upper gastrointestinal bleeding are conditions that can make large demands on health care resources. Acid suppression is common therapy for these conditions. The economic implications of managing Helicobacter pylori-related PUD, GERD, and upper gastrointestinal bleeds were considered by several investigators. Economic analyses of drug regimens for PUD show that eradication is more cost effective than H2-receptor antagonist (H2RA) maintenance therapy. Although various eradication regimens have been compared, the results depend on a number of assumptions that preclude general conclusions regarding cost-effectiveness. Economic analyses related to GERD are hindered by the often chronic, relapsing nature of the disease, particularly once therapy is discontinued. Therefore, as with PUD, results of the economic analyses depend largely on initial assumptions relative to the model employed. With regard to upper gastrointestinal bleeding, proton pump inhibitors (PPIs) are potent acid suppressors that may help prevent rebleeding that was managed endoscopically. Further clinical and economic investigations of PPIs for stress ulcer prophylaxis are necessary. Cost-effectiveness studies comparing PPIs and H2RAs should focus on overall costs of managing these conditions and include economic benefits of preventing complications, and not on drug-acquisition costs alone.

History of Acid Suppression: Focus on the Hospital Setting

In the hospital setting, prophylactic acid suppression is an important part of care for many critically ill patients. It may also prevent rebleeding in patients admitted with acute upper gastrointestinal tract bleeding. Effective treatments for these conditions stemmed from our increased understanding of the gastric acid secretory pathway and target pH values. The late 1970s saw the introduction of histamine2-receptor antagonists (H2RAs), which partially suppress basal and meal-stimulated acid secretion. Some of these agents can induce an intragastric pH greater than 3, lasting for approximately 10 hours/day when given twice/day at recommended doses. This level of acid suppression can facilitate healing of duodenal ulcers but has limited efficacy for other indications (e.g., gastrointestinal bleed). In the late 1980s a more potent class of acid-suppressing agents was developed, proton pump inhibitors (PPIs). The PPIs can induce an intragastric pH above 3 lasting for approximately 17 hours/day, and an intragastric pH above 5 for approximately 9 hours/day after once-daily oral administration of recommended doses. It is possible to attain even higher target pH values with large doses and with continuous intravenous infusion. Thus, PPIs are agents of choice for treatment of many acid-related disorders including peptic ulcer disease and moderate-to-severe gastroesophageal reflux disease, and for prevention of rebleeding in patients with upper gastrointestinal bleeding. Availability of an intravenous formulation, pantoprazole, enables hospitalized patients for whom oral administration is not feasible to benefit from the superior potency of PPIs. Preliminary data suggest that intravenous PPIs may be more effective than H2RA prophylaxis against stress-related ulcer bleeding for intensive care patients and should facilitate healing in those with bleeding ulcers of the upper gastrointestinal tract.

Cefepime microbiologic profile and update

BACKGROUND

The evolution of the cephalosporin class of antibiotics through modifications of the basic cephem structure has resulted in a new generation with improved antibacterial activity. Cefepime is a prototypic agent of this new class of fourth generation cephalosporins.

OBJECTIVE

To review the microbiologic profile of cefepime.

RESULTS

Cefepime, which is a zwitterion, has a net neutral charge that allows it to penetrate the outer membrane of Gram-negative bacteria faster than third generation cephalosporins. It is more stable against beta-lactamases because of the lower affinity of the enzymes for cefepime when compared with third generation cephalosporins. As a result of these structural attributes, cefepime has in vitro activity against pathogens that are prevalent in pediatric infections. This agent offers the advantage of Gram-positive coverage similar to that of cefotaxime and ceftriaxone, as well as good activity against Pseudomonas aeruginosa and many enteric bacilli that are resistant to third generation cephalosporins, including clinical isolates of Enterobacter spp. and Citrobacter freundii.

CONCLUSIONS

Based on its spectrum of activity cefepime is an option for the treatment of pediatric infections caused by susceptible pathogens.

Quality of life measurement clarifies the cost-effectiveness of Helicobacter pylori eradication in peptic ulcer disease and uninvestigated dyspepsia

OBJECTIVES

Previous economic studies of Helicobacter pylori eradication in dyspepsia and peptic ulcer disease have not measured quality of life using utilities (preference probabilities), which are needed to compare the cost-effectiveness of such treatment to other health care interventions. The goals of this study were to measure quality of life in patients with dyspepsia or peptic ulcer and apply these measurements to published models of disease management to determine cost-effectiveness in dollars per quality-adjusted life year (QALY) gained.

METHODS

Utilities for dyspepsia and peptic ulcer disease were measured in adult patients (n = 73) on chronic acid suppression for peptic ulcer or ulcer-like dyspepsia. Median utility values were applied to the results of published cost-effectiveness analyses and a previously validated dyspepsia model. Cost-utility ratios for early H. pylori eradication in uninvestigated dyspepsia and peptic ulcer disease were then computed.

RESULTS

The total disutility, or lost quality of life, for an ulcer was 0.11 QALY, of which 0.09 QALY was attributed to dyspeptic symptoms. After these results were incorporated into published studies, cost-utility ratios for ulcer treatment varied from $3,100 to $12,500 per QALY gained, whereas estimates for uninvestigated dyspepsia management ranged from $26,800 to $59,400 per QALY. Sensitivity analyses indicated a range of $1,300 to $27,300 per QALY for management of duodenal ulcer and $15,000 to $129,700 per QALY for dyspepsia.

CONCLUSIONS

Strategies that emphasize early H. pylori eradication were cost-effective for patients with peptic ulcer and possibly cost-effective for patients with uninvestigated dyspepsia, relative to other medical interventions. Dyspeptic symptoms cause significant disutility that should be incorporated in future cost-effectiveness analyses of treatment strategies.

Treatment options for extended-spectrum beta-lactamase-producers

A review of antibiotic options for the treatment of infections caused by extended-spectrum beta-lactamase-producing isolates is presented. The use of the third-generation cephalosporin, cefotaxime, for infections caused by isolates producing ceftazidimase-type extended-spectrum beta-lactamases is controversial, despite in vitro susceptibility to the antibiotic in many instances. The fourth-generation cephalosporin, cefipime, although active against most extended-spectrum beta-lactamases, is reported to show a marked inoculum effect. The cephamycins, such as cefoxitin. are generally effective against Enterobacteriaceae producing TEM- and SHV-derived extended-spectrum beta-lactamases, but Klebsella pneumoniae strains are prone to cephamycin resistance as a result of porin loss. The use of beta-lactamase inhibitor combinations is variable. Sulbactam is less effective than clavulanate for the inhibition of SHV-derived extended-spectrum beta-lactamases and a marked inoculum effect has been noted, while the efficacy of tazobactam against SHV-derived extended-spectrum beta-lactamase producers is controversial. Furthermore, extended-spectrum beta-lactamases are often encoded by multi-resistant plasmids carrying genes conferring resistance to aminoglycosides, chloramphenicol, sulfonamides, trimethoprim and other antimicrobials, severely limiting even alternative therapies. Extensive susceptibility testing before the institution of antibiotic therapy is thus vital.

In vitro evaluation of cefepime and other broad-spectrum beta-lactams for isolates in Malaysia and Singapore medical centers. The Malaysia/Singapore Antimicrobial Resistance Study Group

The degree of activity of several beta-lactam antimicrobial agents was assessed in Malaysia (four medical centers) and Singapore (two medical centers) tested against 570 clinical isolates. The organisms were tested locally by the Etest (AB BIODISK, Solna, Sweden) method, validated by concurrent use of quality assurance strains (94.1% accurate performance overall). Ten groups of bacteria were tested against cefepime, cefpirome, ceftazidime, ceftriaxone, piperacillin/tazobactam, oxacillin, and imipenem. Among the tested Escherichia coli and Klebsiella spp., the occurrence of extended spectrum beta-lactamase-producing phenotypes was 5.6-7.0% and 36.7-38.0%, respectively. These strains remained most susceptible (97.5-100.0%) to cefepime and imipenem. Ceftazidime-resistant Enterobacter spp. (21.4% resistant), Citrobacter spp. (15.0%), indole-positive Proteus spp. (6.0%), and Serratia spp. (9.7%) were not resistant to cefepime, and only one strain was resistant to imipenem. Imipenem was generally most potent against non-fermentative Gram-negative bacilli such as Acinetobacter spp. and Pseudomonas aeruginosa. All tested beta-lactams were active against the oxacillin-susceptible staphylococci, except ceftazidime (MIC90, 12 micrograms/mL; 63.2-84.8% susceptibility rates). Overall spectrums of activity (rank by % resistance) favored imipenem (3.5%) > cefepime (7.7%) > cefpirome (8.9%) > piperacillin/tazobactam (13.2%) > ceftriaxone (14.7%) > ceftazidime (16.9%). No significant differences in resistance patterns were noted between monitored nations, and these results indicate emerging, elevated rates of resistance versus the studied broad-spectrum beta-lactams in Malaysia and Singapore. Results provide benchmark data for future studies using quantitative methods to determine antimicrobial resistance in these geographic areas.

In vitro evaluation of broad-spectrum beta-lactams in the philippines medical centers: role of fourth-generation cephalosporins. The Philippines Antimicrobial Resistance Study Group

Cefepime is a potent broad-spectrum "fourth-generation" cephalosporin. The in vitro activity of cefepime was compared to that of cefpirome, ceftazidime, ceftriaxone, imipenem, and piperacillin/tazobactam in a multilaboratory (nine medical centers) Philippine surveillance project from March through October 1998. A total of 626 Gram-positive and Gram-negative organisms (10 species groups) were tested by the Etest method (AB BIODISK, Solna, Sweden) with results validated by current quality control strain analysis. The overall rank order of usable spectrum of activity was imipenem (4.2% resistance), cefepime (4.5%), cefpirome (5.0%), piperacillin/tazobactam (5.8%) > ceftriaxone (11.2%) > ceftazidime (15.3%), and results did not differ significantly between medical centers. Ceftazidime-resistant Escherichia coli and Klebsiella spp. occurred at rates of 13.3% and 31.1%, respectively, indicating extended-spectrum beta-lactamase (ESBL) activity. Imipenem (100% susceptible), cefepime, and cefpirome (both > or = 97.8% susceptible) were active in vitro against these ESBL phenotypes. Organisms with ceftazidime and/or ceftriaxone-resistant profiles consistent for hyper-production of Amp C cephalosporinases were detected at high rates among the Citrobacter spp. (29.2%) and Enterobacter spp. (45.8%); however, imipenem (100.0% susceptible) and cefepime (98.9%) remained active. Cefepime and imipenem (both 87.5% susceptible) were the most active agents tested against Acinetobacter spp. whereas piperacillin/tazobactam was most effective against P. aeruginosa (80.0% susceptible). Most tested beta-lactams (except ceftazidime) were active versus oxacillin-susceptible staphylococci. These data should be used as a guide for treatment selection with beta-lactam compounds in the Philippines and to serve as a resistance benchmark in comparisons with future studies in this nation.

Evaluation of the in vitro activity of six broad-spectrum beta-lactam antimicrobial agents tested against over 2,000 clinical isolates from 22 medical centers in Japan. Japan Antimicrobial Resistance Study Group

Numerous broad-spectrum beta-lactam antimicrobial agents have been introduced into medical practice since 1985. Although several of these compounds have advanced, infectious disease therapy resistances to them has also emerged world-wide. In 1997, a Japanese 22 medical center investigation was initiated to assess the continued utility of these agents (oxacillin or piperacillin, ceftazidime, cefepime, cefpirome, cefoperazone/sulbactam [C/S], imipenem). The participating medical centers represented a wide geographic distribution, and a common protocol and reagents were applied. Three control strains and a set of challenge organisms were provided to participant centers. Etest (AB BIODISK, Solna, Sweden) strips were used in concurrent tests of these organisms and a qualitative determination of participant skills in the identification of resistant and susceptible phenotypes was established. The quantitative controls demonstrated 97.7-99.2% of MIC values within established QC limits, and the qualitative (susceptibility category) controls documented a 97.3% agreement of participant results with that of reference values (1,320 total results). Only 0.2% of values were false-susceptible errors. After the participant quality was assured, a total of 2,015 clinical strains were tested (10 strains from 10 different organism groups including methicillin-susceptible Staphylococcus aureus and coagulase-negative staphylococci [CoNS], Escherichia coli, Klebsiella spp., Citrobacter freundii, Enterobacter spp., indole-positive Proteae, Serratia spp., Acinetobacter spp., and Pseudomonas aeruginosa). The staphylococci were uniformly susceptible to all drugs tested except ceftazidime (MIC90, 24 micrograms/ml) that had a potency six- to 12-fold less than either cefepime or cefpirome. Only 3.7 and 45.1% of S. aureus and CoNS were susceptible to ceftazidime, respectively. Among E. coli and Klebsiella spp. the rank order of antimicrobial spectrum was imipenem = "fourth-generation" cephalosporins > ceftazidime > C/S > piperacillin. Possible extended spectrum beta-lactamase phenotypes were identified in 2.9-8.6% of these isolates. Isolates of C. freundii, Enterobacter spp., Proteae, and Serratia spp. that were resistant to ceftazidime and piperacillin remained susceptible to imipenem (0.0-4.5% resistance) and cefepime (0.0-5.0%). Acinetobacters were inhibited best by C/S (99.5% susceptible) and least susceptible to piperacillin (MIC90, > 256 micrograms/ml; 21.7% susceptible) activity. P. aeruginosa isolates were most susceptible to cefepime (83.6%) and this zwitterionic cephalosporin also had the lowest level of resistance (9.1% of MICs at > or = 32 micrograms/ml). Several multi-resistant organisms were identified in participant medical centers including S. marcescens strains resistant to cefepime, imipenem, or both observed in six hospitals. Clonal spread was documented in two medical centers; one hospital having two distinct epidemic clusters. Also a multi-resistant E. cloacae was found in two patients in the same hospital. Evaluations of carbapenem resistance in four species discovered only two strains (in same hospital) among 40 P. aeruginosa isolates (5.0%) with a metallo-enzyme, with nearly all of the remaining strains inhibited by an Ambler Class C enzyme inhibitor (BRL42715) indicating a hyperproduction of a chromosomal cephalosporinase. These results indicate that most newer beta-lactams remain widely useable in medical centers in Japan, but emerging often clonal, resistances have occurred. The overall rank order of antimicrobial spectrum against all ten tested bacterial groups favors the "fourth-generation" cephalosporin, cefepime (96.4% susceptible) as an equal to imipenem (95.9%) > C/S (90.9%) = cefpirome (90.0%) > ceftazidime (75.1%) = penicillins, either oxacillin or piperacillin (76.4%).

Treatment of community-acquired pneumonia in the elderly: the role of cefepime, a fourth-generation cephalosporin

In a prospective, multicentre double-blind trial, 151 patients over the age of 65 years were randomly assigned to receive either cefepime 2 g every 12 h for a minimum of 3 days and up to 14 days or ceftriaxone 1 g every 12 h for a minimum of 3 days and up to 14 days. Antibiotics were maintained until 48 h after fever had resolved; no other antibiotics were permitted. The average age in each group exceeded 77 years and significant co-morbidity was found in the majority of patients. The mean total duration of therapy was 5.8+/-2.4 days for the cefepime group and 6.7+/-2.7 days for the ceftriaxone group (P = 0.06). The clinical success rate at the end of therapy was 79.1% with cefepime and 75.4% with ceftriaxone (P = 0.62). At the end of follow-up, 91.7% of the cefepime-treated patients and 86.5% of the ceftriaxone patients had a satisfactory clinical response (P = 0.38). In 35 bacteriological evaluable patients, potential pathogens were eradicated in all but one patient receiving cefepime. Seven patients in each group died during the study period but in each case the death was unrelated to study drug. The commonest side-effect was diarrhoea (cefepime, five patients; ceftriaxone, two patients). The clinical and microbiological efficacy of cefepime is similar to that of ceftriaxone in elderly patients with community-acquired pneumonia requiring hospitalization. Cefepime is an appropriate choice for the treatment of community-acquired respiratory tract infections in the elderly.

Cefepine vs. ceftazidime treatment of pyelonephritis: a European, randomized, controlled study of 300 pediatric cases. European Society for Paediatric Infectious Diseases (ESPID) Pyelonephritis Study Group

BACKGROUND

Cefepime has been used in clinical therapeutic trials for meningitis, serious infection and febrile neutropenia, comprising more than 800 pediatric patients. This agent has also been used in patients 12 years of age and older with uncomplicated and complicated urinary tract infections including pyelonephritis, but not in younger patients. In this study the safety and efficacy of cefepime were compared with those of ceftazidime for treatment of pyelonephritis in pediatric patients younger than 12 years of age.

METHODS

Two hundred ninety-nine pediatric patients (ages 1 month to 12 years) with pyelonephritis (300 episodes) were enrolled in a randomized, open label, multicenter trial. Individual results were evaluated by a blinded committee of experts. Cefepime was compared with ceftazidime, both administered parenterally at 50 mg/kg every 8 h. Patients were to receive the assigned study drug until at least 48 h after becoming afebrile. The i.v. treatment was then to be continued or replaced by oral trimethoprimsulfamethoxazole for a maximum of 12 to 14 days.

RESULTS

The predominant causative pathogens were Escherichia coli, 88%; Proteus spp., 6%; Pseudomonas aeruginosa, 2%; and Klebsiella spp., 2%. Bacteriologic eradication was achieved in 96 and 94% of cefepime and ceftazidime patients, respectively, at the end of i.v. study drug treatment and was maintained in 94 and 91%, respectively, at the end of total study therapy. After study therapy bacteriologic eradication was maintained after 4 to 6 weeks in 86% of cefepime cases and in 83% of ceftazidime cases. A satisfactory clinical response occurred in 98 and 96% of cefepime and ceftazidime patients, respectively, at the end of i.v. treatment and in 93% at the end of total study therapy in both treatment arms. Drug-related clinical adverse events occurred in 14 cefepime patients (91%) and in 10 ceftazidime patients (7%).

CONCLUSIONS

Cefepime and ceftazidime are equally safe and efficacious treatment for pyelonephritis in pediatric patients.

Cefepime versus ceftriaxone for empiric treatment of hospitalized patients with community-acquired pneumonia. The Cefepime Study Group

Effective empiric treatment of pneumonia requires antibiotic coverage against gram-negative and gram-positive pathogens, including drug-resistant isolates. We compared the safety and efficacy of intravenous (i.v.) cefepime (2 g administered every 12 h) to those of i.v. ceftriaxone (1 g administered every 12 h) for the empiric treatment of hospitalized patients with community-acquired pneumonia. Of the 115 patients randomized to the study, 86 (cefepime recipients, n = 40; ceftriaxone recipients, n = 46) were evaluated for clinical efficacy (clinically evaluated patients). Favorable clinical outcomes (cure or improvement) were comparable among clinically evaluated patients in the cefepime and ceftriaxone treatment arms (95.0 versus 97.8%, respectively; 95% confidence interval for treatment difference [data for ceftriaxone group minus data for cefepime group], -5.1 to +10.8%). The most common bacteria isolated from patients in both treatment groups were Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus. In clinically evaluated patients with a microbiologic response, all (100%) of the 32 pathogens from cefepime-treated patients and 97.4% (38 of 39) of the pathogens from ceftriaxone-treated patients were eradicated (documented or presumed eradication). The one persistent infection in the ceftriaxone group was caused by Pseudomonas fluorescens. Both treatments were well tolerated. Our data thus suggest that cefepime and ceftriaxone have comparable safety and efficacy for the treatment of pneumonia in hospitalized patients.

Antimicrobial activity and spectrum investigation of eight broad-spectrum beta-lactam drugs: a 1997 surveillance trial in 102 medical centers in the United States. Cefepime Study Group

Because antimicrobial agents become less effective after the emergence of resistance mechanisms in clinically prevalent pathogens, physicians must utilize local, regional, and national antimicrobial susceptibility surveillance data to assist in choices of appropriate agents. An investigation of the spectrum and potency of eight broad-spectrum beta-lactam drugs (cefepime, cefotaxime, ceftazidime, ceftriaxone, imipenem, piperacillin with or without tazobactam, and ticarcillin/clavulanic acid) was performed using a common protocol and method (Etest; AB BIODISK, Solna, Sweden) in 102 clinical microbiology laboratories in the United States. A total of 9777 strains of Gram-negative bacilli were tested from late 1996 through April 1997. Quality assurance measures using three control strains observed quality control failures in 13 laboratories (usually ticarcillin/clavulanic acid or piperacillin), but only 2% of results required deletion. A total of 33.4% of Enterobacter spp. (1977 strains) were either resistant or intermediately susceptible to ceftazidime. Only imipenem (99.6% susceptible) and cefepime (99.1%) remained highly active against strains of Enterobacter, as well as Citrobacter freundii, indole-positive Proteae, and Serratia spp. Ceftazidime-resistant Escherichia coli and Klebsiella pneumoniae were detected at rates of 10.3% and 23.8%, respectively. Although these were participant-selected strains, only imipenem and cefepime had broad-spectrum coverage (> or = 97.1%) against these extended-spectrum beta-lactamase phenotypes. A dominant number of these extended-spectrum beta-lactamase phenotypes were reported from medical centers in the Northeast, but a nationwide distribution was observed. Among the nonenteric Gram-negative bacilli (4057 strains), the rank order of susceptibility (percent inhibited at published breakpoint concentrations) was: imipenem (86.1%) > piperacillin/tazobactam (80.1%) > cefepime (77.1%) > ceftazidime = piperacillin (74.9%) > ticarcillin/clavulanic acid (61.6%) > cefotaxime (18.2%) > ceftriaxone (12.9%). The cephalosporins, cefepime and ceftazidime, had rates of resistance for the 3005 Pseudomonas aeruginosa isolates of 10.1% and 14.4%, respectively. For all Gram-negative strains tested, only two contemporary beta-lactam antimicrobials exhibited > 90% inhibition of strains, imipenem at 93.6% and cefepime at 90.2%. These drugs were superior to the other tested compounds (48.8-84.3%). Ticarcillin/clavulanic acid had the narrowest spectrum of activity (48.8% of isolates susceptible). These results indicate that carbapenems and a new fourth-generation cephalosporin, cefepime, possess usable in vitro potencies against current clinical strains of Gram-negative bacilli, many of which harbored resistance to other antimicrobial agents.

Multicenter evaluation of the antimicrobial activity for six broad-spectrum beta-lactams in Venezuela using the Etest method. The Venezuelan Antimicrobial Resistance Study Group

In early 1997, a 15-laboratory surveillance project was initiated in Venezuela to monitor the potency and spectrum of 6 broad-spectrum antimicrobial agents (cefepime, cefotaxime, ceftazidime, piperacillin, piperacillin/tazobactam, and imipenem) tested against approximately 100 organisms per participant center (1297 strains). Ten groups of organisms were tested by the Etest method (AB BIODISK, Solna, Sweden) with results validated by concurrent quality control strain analysis. Results from all centers were tabulated and 96.3% of quality assurance tests were within ranges recommended by the National Committee for Clinical Laboratory Standards. Among the six beta-lactam class drugs tested, imipenem and cefepime were the most active against all isolates tested. Overall, the rank order of susceptibility of the six agents was imipenem (97.2%, susceptible; MIC90 2 micrograms/ml) > cefepime (92.8%; MIC90 6 micrograms/mL) > piperacillin/tazobactam (77.2-83.0%; MIC90 > 256 micrograms/mL) > cefotaxime (72.2%; MIC90 > 256 micrograms/mL) > piperacillin (56.8-65.8%; MIC90 > 256 micrograms/mL) > ceftazidime (64.66%; MIC90 128 micrograms/mL). Both cefepime and imipenem were active against ceftazidime-resistant strains of Enterobactericaeae as well as against Pseudomonas aeruginosa and oxacillin-susceptible staphylococci. Resistance phenotypes consistent with extended spectrum beta-lactamases (ESBLs) and stably derepressed Bush group 1 cephalosporinases were documented in strains of Klebsiella spp. and Enterobacters, respectively. These data should be used to guide empiric therapy with beta-lactams in Venezuela, and additionally will provide a reference statistical baseline to which future studies in this nation can be compared.

Multicenter evaluation of antimicrobial resistance to six broad-spectrum beta-lactams in Colombia using the Etest method. The Colombian Antimicrobial Resistance Study Group

The need for comprehensive and quantitative accurate antimicrobial resistance surveillance systems has become acute as a guide to problem recognition and to focus local interventions. A multilaboratory (10 medical centers) Colombia surveillance project was initiated in early 1997 to monitor the potency and spectrum of six (cefepime, cefotaxime, ceftazidime, cefoperazone/sulbactam, aztreonam, and imipenem) broad-spectrum antimicrobial agents tested against 100 organisms per participant center (802 strains). Ten groups of organisms were tested by a reference-quality method (Etest; AB BIODISK, Solna, Sweden) with results validated by concurrent quality control and additional challenge strain analysis. Results from nine qualifying medical centers were tabulated, and 95.7 to 96.8% of quality assurance tests were within expected ranges. Only cefepime (90.1-100.0% susceptible) and imipenem (96.3-100.0%) were active against all Enterobacteriaceae at > 90% of susceptible isolates using the breakpoint concentrations recommended by the National Committee for Clinical Laboratory Standards. Among ceftazidime- (or cefotaxime- or aztreonam-) resistant Enterobacter spp. and Citrobacter freundii, cefepime remained active, but not cefoperazone with sulbactam. Escherichia coli and Klebsiella spp. strains having resistance phenotypes consistent with extended spectrum beta-lactamase production were discovered in approximately 5 to 10% of isolates. All tested drugs except ceftazidime (31.8-57.7% susceptible) were active against > 94% of oxacillin-susceptible staphylococci. Similar rates of resistance (9.1-14.8%) were observed in Pseudomonas aeruginosa for five of six drugs (not cefotaxime; 15.9% of strains were susceptible). Acinetobacter spp. isolates were most susceptible to imipenem (95.8%), cefepime (86.1%), and cefoperazone/sulbactam (83.3%). Overall for the 1997 order of antimicrobial spectrums for these tested compounds was: imipenem (96.6%) > cefepime (93.6%) > cefoperazone/sulbactam (90.5%) > cefotaxime (74.9%) > aztreonam (74.3% for Gram-negative bacilli only) > ceftazidime (73.2%). These data should be used to guide empiric regimens in Colombia, and additionally will provide a resistance statistical baseline to which future studies in this nation can be compared.

Impact of changing pathogens and antimicrobial susceptibility patterns in the treatment of serious infections in hospitalized patients

The selection of drug-resistant pathogens in hospitalized patients with serious infections such as pneumonia, urinary tract infections (UTI), skin and skin-structure infections, and primary or secondary bacteremia has generally been ascribed to the widespread use of antimicrobial agents. Issues of concern regarding gram-negative bacilli include the expression of extended spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumonias and constitutive resistance in some Enterobacteriaceae caused by Bush group 1 beta-lactamases. Current concerns with gram-positive pathogens are increasing multidrug resistance in methicillin-resistant Staphylococcus aureus, enterococci, and coagulase-negative staphylococci, and increasing incidence of penicillin-resistant Streptococcus pneumoniae. Contemporary treatment strategies for pneumonia in hospitalized patients mandate early empiric therapy for the most likely gram-positive and gram-negative pathogens. Newer beta-lactams, such as fourth-generation cephalosporins, may be useful in the treatment of pneumonia, including those cases associated with bacteremia. Combination beta-lactam/beta-lactamase inhibitor drugs, an aminoglycoside co-drug, or a carbapenem may also be indicated. The initial treatment of UTI in the hospital setting also may be empirically treated with the newer cephalosporins, combination broad-spectrum penicillins plus an aminoglycoside, a quinolone, or a carbapenem. Current problems in treating UTI include the emergence of extended spectrum beta-lactamase-producing Escherichia coli, the tendency of fluoroquinolones both to select for resistant strains of major UTI pathogens and to induce cross-resistance among different drug classes, and beta-lactam and vancomycin resistance of enterococci and coagulase-negative staphylococci. Treatment of skin and skin-structure infections is complicated by the coexistence of gram-positive and gram-negative infections, which may be drug resistant. Both fourth-generation beta-lactams and carbapenems may have in vitro activity against these pathogens; however, where these drugs--with their increased spectra and lower affinity for beta-lactamases and less susceptibility to beta-lactamase hydrolysis--fit into the therapeutic armamentarium remains to be determined. Initial clinical studies appear to be promising, nonetheless. The ability of both nosocomial and community-acquired pathogens to develop resistance to powerful broad-spectrum agents presents a great challenge for prescribing patterns and in the development of new drugs to be relatively resistant to inactivation.

Safety of cefepime: a new extended-spectrum parenteral cephalosporin

The purpose of this study was to compare the safety profile of cefepime, a new extended-spectrum, fourth-generation cephalosporin used to treat mild-to-severe bacterial infections, with that of ceftazidime. A total of 2,032 patients enrolled in North American and European cefepime trials were analyzed. The study population spanned adolescence to the elderly (15-100 years); the median age was 62 years. Cefepime was compared with ceftazidime (1,456 patients), a third-generation cephalosporin. Cefepime dosing was 1-4 g/day (0.5-2.0 g twice daily) for adults; ceftazidime dosing was 1-6 g/day (0.5 g every 12 hours to 2.0 g every 8 hours). A limited number of cefepime-treated patients received 2 g every 8 hours. The median length of dosing for both cefepime and ceftazidime was 7 days. In randomized trials in which cefepime (2,032 patients) was compared with ceftazidime (1,456 patients), analysis of comparative data indicated that adverse events of probable or unknown relation to study drugs were observed in 13.8% of cefepime patients and 15.6% of ceftazidime patients. The most commonly observed adverse event for cefepime was headache (2.4%), followed by nausea (1.8%), rash (1.8%), and diarrhea (1.7%). For ceftazidime, the most commonly observed adverse event was diarrhea (3.2%), followed by headache (2.5%), nausea (2.1%), rash (1.9%), and constipation (1.5%). The incidence of positive Coombs' test was higher in high-dose cefepime recipients than in ceftazidime recipients (14.5% vs 8.7%; p = 0.043), although there was no evidence of hemolysis in either treatment group. Coadministration of analgesics, diuretics, and anticoagulants did not increase incidence of adverse events associated with study-drug therapy. Adverse renal and hematologic events, as well as anaphylaxis and death, were rare in both groups. In the comparative trials with cefepime, anaphylaxis was reported in no patients receiving cefepime and in one patient receiving ceftazidime. None of the three seizures reported in patients receiving cefepime and one of six seizures in patients receiving ceftazidime were of probable or possible relationship to the study drugs. None of the 12 cases of gastrointestinal hemorrhage reported in cefepime patients or five cases reported in ceftazidime patients were judged to be related to treatment drug. Tolerance for intravenous administration in both treatment groups was similar. Cefepime did not effect any significant or unusual allergic, hematologic, gastrointestinal, neurologic, or renal toxicity when administered to patients with mild-to-severe infections, including those receiving concomitant medications. The safety profile of cefepime is excellent and comparable to that of ceftazidime and those reported for other cephalosporins.