Treatment of urinary tract infections: selecting an appropriate broad-spectrum antibiotic for nosocomial infections

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.

Evaluation of efficacy and tolerability of cefotaxime and sulbactam versus cefepime and tazobactam in patients of urinary tract infection-a prospective comparative study

OBJECTIVE

Urinary tract infection (UTI) is the third most common infection experienced by humans after respiratory and gastro-intestinal infections. Cephalosporins are now widely been used in UTI, but emerging resistance is a problem to that. Our study aims at evaluating efficacy and safety of third generation cephalosporin combined with beta lactamase inhibitors compared with fourth generation cephalosporin.

MATERIALS AND METHODS

The present, open, randomised, parallel group comparative study includes 60 patients of urinary tract infection. Group A patient were put on treatment regimen of cefotaxime and sulbactam (0.5-2 gms IV/IM BD) and Group B patients were prescribed cefepime and tazobactam (0.5-1 gm IV/IM BD) depending upon urine culture and sensitivity pattern of causative agent and condition of the patient. Bacteriological cure rate, clinical cure rate will be assessed for efficacy and adverse drug reaction (ADR) recorded for evaluating safety.

RESULTS

The study showed a male predominance with 37 males (61.6%) and 23 (38.4%) females out of the total 60 patients with a maximum number within the age group of 50-70., and the most common organism isolated was E coli (73.3%), in rest of the patients Klebsiella (13.33%), Proteus (6.66%), and Staphylococcus (6.66%) were isolated. The overall bacteriological cure rate, in the present study, with cefotaxime/sulbactam and cefepime/tazobactam was 86.5%±6.5 and 93.3%±6.7 respectively. The clinical cure rate post five days of therapay, in goup A1 was 79.03%±2.82 and the same in group B1 was 87% ± 2.11. The clinical cure rate post ten days of therapy in group A2 98.57±0.03 and the same in group B2was 100%. Overall success rate as evaluated by our data in the present study in group A i.e those treated with cefotaxime/sulbactam was 89.28±9.1% and in group B i.e. those treated with cefepime/ tazobactam and 94.49±5.06%.

CONCLUSION

From the present study, those drugs in both generations of cephalosporins combined with beta lactamase inhibitors cefotaxime/sulbactam and cefepime/tazobactam were equally effective and well tolerated in the treatment of UTI. However the cost effectiveness and safety parameters are the important deciding factors for prescribing the same.

The safety of cefepime in the treatment of infection

BACKGROUND

Cefepime is a fourth-generation cephalosporin usually reserved for treating severe nosocomial pneumonia, as well as empirical treatment of febrile neutropenia, uncomplicated and complicated urinary tract infections, uncomplicated skin and skin structure infections, and complicated intra-abdominal infections.

OBJECTIVE

Since reports of neurotoxic effects and of an all-cause mortality higher with cefepime than with comparators have created some concerns regarding its safety, this paper reviews data available in the PubMed database up to December 2007 on cefepime safety.

METHODS

Literature data from PubMed obtained by combining cefepime and safety, or cefepime and clinical trials, were examined.

RESULTS/CONCLUSIONS

Caution in the use of cefepime should be adopted until new evidence on cefepime safety is available.

Intensive care unit-acquired urinary tract infections in patients admitted with sepsis: etiology, risk factors, and patterns of antimicrobial resistance

OBJECTIVES

The objective of the present study was to evaluate the etiology, risk factors, and patterns of antimicrobial resistance of intensive care unit (ICU)-acquired urinary tract infections (UTIs) in patients admitted with sepsis.

METHODS

In this observational study, 100 septic patients hospitalized in a general ICU were selected. Demographic, clinical, and outcome data were obtained by chart review. Antibiotic resistance/susceptibility was determined using the minimal inhibitory concentration (MIC) technique.

RESULTS

A UTI was present in 28 (28%) patients; the male to female ratio was 19:9 and the mean age of the patients was 58.71+/-19.45 years. From the total of 28 isolates, 27 were resistant to ciprofloxacin, 23 to amikacin, 27 to meropenem, 28 to cefepime, 26 to ceftazidime, and 27 to ceftriaxone.

CONCLUSIONS

On the basis of our results, the rate of multidrug-resistant UTIs may be very high in some ICUs in patients admitted with sepsis. This antimicrobial susceptibility/resistance should be determined, and a special antimicrobial treatment protocol should be planned based on the results for each ICU. The use of antibiotics for treating UTIs should be guided only through this protocol because of the different spectra of pathogens and susceptibility patterns in each ICU.

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.

Cephalosporins, carbapenems, and monobactams

Nonpenicillin beta-lactams exhibit a variable spectrum of antimicrobial activity, have a wide range of clinical uses and a favorable safety profile. Cefepime's twice-daily dosage and increased activity against Enterobacteriaceae may offer some advantages over older cephalosporins. The carbapenems offer a broad antimicrobial spectrum, and meropenem has an improved safety profile compared with imipenem. Aztreonam is a useful alternative for patients with aerobic gram-negative infections who are allergic to penicillin. The emergence of resistant organisms, however, is an increasing problem with the frequent use of these antibiotics.

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%).

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.

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 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.