Piperacillin 2 g/tazobactam 0.5 g is as effective as imipenem 0.5 g/cilastatin 0.5 g for the treatment of acute uncomplicated pyelonephritis and complicated urinary tract infections

Antibacterial data synthesis challenges: a systematic review of treatments for complicated gram-negative urinary tract infections

Aim: To determine the suitability of network meta-analysis (NMA) using antibacterial treatment evidence in complicated urinary tract infection. Materials & methods: We conducted a systematic literature review to identify published clinical trial data for complicated urinary tract infection treatments. We performed a feasibility assessment to determine whether the available evidence would support the creation of a robust NMA, considering key assumptions of homogeneity, similarity and consistency. Results: Twenty-five trials met eligibility criteria. Risk of bias was low, and individual studies met their primary end point(s). Assumptions central to the conduct of a robust NMA were not met. Heterogeneity was ubiquitous, including baseline pathogen, treatment and patient characteristics. Conclusion: Limited and heterogeneous data identified make the use of NMA to compare novel antibacterial agents impractical and likely unreliable.

Epidemiology, definition and treatment of complicated urinary tract infections

UTIs are amongst the most frequent bacterial infections. However, the clinical phenotypes of UTI are heterogeneous and range from rather benign, uncomplicated infections to complicated UTIs (cUTIs), pyelonephritis and severe urosepsis. Stratification of patients with UTIs is, therefore, important. Several classification systems exist for the description and classification of UTIs, with the common rationale that cUTIs have a higher risk of recurrence or chronification, progression or severe outcome than uncomplicated UTIs. The pathophysiology and treatment of cUTIs and pyelonephritis are driven more by host factors than by pathogen attributes. cUTIs and pyelonephritis are associated with high antimicrobial resistance rates among causative pathogens. However, antimicrobial resistance rates can differ substantially, depending on the population being studied and whether the data being analysed are from surveillance studies, registry data or interventional studies, in which specific inclusion and exclusion criteria are used for patient selection. For example, antibiotic resistance rates are higher in patients with urosepsis than in those with less severe infections. Thus, treatment outcomes differ substantially among studies, ranging from 50% to almost 100% clearance of infection, depending on the patient population analysed, the UTI entities included and the primary outcome of the study. Pyelonephritis and cUTIs have emerged as infection models for the study of novel antibiotics, including extensive investigation of novel substances active against Gram-negative bacteria.

Carbapenems vs alternative antibiotics for the treatment of complicated urinary tract infection: A systematic review and network meta-analysis

BACKGROUND

Complicated urinary tract infections (cUTI) are universal reasons for hospitalization, and highly likely to develop into sepsis or septic shock. Carbapenem antibiotics with potentially higher efficacy or with fewer and milder side effects have increased in popularity, but evidence is limited by a scarcity of randomized controlled trials (RCTs) comparing different carbapenem antibiotics for cUTI. Network meta-analysis is a useful tool to compare multiple treatments when there is limited or no direct evidence available.

OBJECTIVE

The aim of this study is to compare the efficacy and safety of different carbapenems with alternative antibiotics for the treatment of cUTI.

METHODS

Pubmed, Medline, CENTRAL, and Embase were searched in November 2018. Studies of cUTI patients receiving carbapenem were included. We performed network meta-analysis to estimate the risk ratio (RR) and 95% credible interval (CrI) from both direct and indirect evidence; traditional meta-analysis was also performed. Primary outcomes were clinical and microbiological treatment success.

RESULTS

A total of 19 studies and 7380 patients were included in the analysis. Doripenem (DOPM) was associated with lower clinical treatment success rates than other carbapenems. Although the efficacy of other carbapenems by RRs with 95% CrIs did not show statistical differences, the cumulative rank probability indicated that meropenem/vaborbactam (MV), ertapenem (ETPM), and biapenem (BAPM) had higher clinical and microbiological treatment success rates; imipenem/cilastatin (IC) and MV showed higher risk of adverse events (AEs).

CONCLUSIONS

MV was associated with higher treatment success rates for cUTI, especially for cUTI caused by carbapenem-resistant uropathogens, but also with higher risk of AEs. Our findings suggest MV as a first-choice treatment of carbapenem-resistant cUTI. ETPM, BAPM, and meropenem (MEPM) is another reasonable choice for cUTI empiric therapy.

Factors associated with the recurrence of acute pyelonephritis caused by extended-spectrum β-lactamase-producing Escherichia coli: the importance of infectious disease consultation

To investigate factors for the recurrence of acute pyelonephritis (APN) caused by extended-spectrum β-lactamase-producing Escherichia coli (ESBL-PE), a retrospective cohort study was performed at a tertiary-care hospital from 2014 through 2016. Among 135 patients who had recovered from APN caused by ESBL-PE, the 1-year cumulative recurrence rates of APN caused by any pathogen or by ESBL-PE specifically were 35.6% and 22.1%, respectively. In a multivariate analysis, infectious disease (ID) consultation was associated with decreased recurrence (95% confidence interval [CI] = 0.24-0.96, P = 0.038 for recurrence caused by any pathogen; and 95% CI = 0.15-0.84, P = 0.019 for recurrence caused by ESBL-PE). History of APN within 1 year was a risk factor for recurrent APN caused by any pathogen (P = 0.011). Microbiological cure was a preventive factor for recurrent APN caused by ESBL-PE (P = 0.024). In conclusion, our data show that ID consultation protects against APN recurrence caused by ESBL-PE.

Usefulness of Blood Cultures and Radiologic Imaging Studies in the Management of Patients with Community-Acquired Acute Pyelonephritis

Background

The objective of this study was to examine the usefulness of blood cultures and radiologic imaging studies for developing therapeutic strategies in community-acquired acute pyelonephritis (CA-APN) patients.

Materials and Methods

We prospectively collected the clinical data of CA-APN patients who visited 11 hospitals from March 2010 to February 2011.

Results

Positive urine and blood cultures were obtained in 69.3% (568/820) and 42.7% (277/648), respectively, of a total of 827 CA-APN patients. Blood culture identified the urinary pathogen in 60 of 645 (9.3%) patients for whom both urine and blood cultures were performed; the organisms isolated from urine were inconsistent with those from blood in 11 and only blood cultures were positive in 49 patients. Final clinical failure was more common in the bacteremic patients than the non-bacteremic ones (8.0% vs. 2.7%, P = 0.003), as was hospital mortality (3.6% vs. 0.3%, P = 0.003). Likewise, durations of hospitalization and fever were significantly longer. Bacteremia was independent risk factor for mortality (OR 9.290, 1.145-75.392, P = 0.037). With regard to radiologic studies, the detection rate of APN was 84.4% (445/527) by abdominal computed tomography and 40% (72/180) by abdominal ultrasonography. Eighty-one of 683 patients (11.9%) were found to have renal abscess, perinephric abscess, urolithiasis, hydronephorosis/hydroureter or emphysematous cystitis, which could potentially impact on clinical management. Patients with Pitt score ≥ 1, flank pain or azotemia were significantly more likely to have such structural abnormalities.

Conclusion

Blood cultures are clinically useful for diagnosis of CA-APN, and bacteremia is predictive factor for hospital mortality. Early radiologic imaging studies should be considered for CA-APN patients with Pitt scores ≥1, flank pain or azotemia.

Treatment efficacy and superinfection rates in complicated urinarytract infections treated with ertapenem or piperacillin tazobactam

BACKGROUND/AIM

In this retrospective study, the efficacy of ertapenem and piperacillin tazobactam was compared in the treatment of complicated urinary tract infections (cUTIs). Treatment responses were also evaluated for both antibiotics.

MATERIALS AND METHODS

A total of 230 patients were enrolled in the study. Of these, 170 received ertapenem and 60 received piperacillin-tazobactam.

RESULTS

In both groups, urine cultures after 48 h were negative for the initial uropathogen. The frequency of superinfection was 29.4% in the ertapenem group and 8.3% in the piperacillin-tazobactam group over the duration of treatment (P < 0.05). Urinary catheterization increased the superinfection risk 2.88-fold in the ertapenem group and diabetes mellitus increased the risk 8.50-fold in the piperacillin-tazobactam group (CI: 1.44-5.76 and 1.16-62.09, respectively, P < 0.05). The main pathogen isolated from superinfection in the ertapenem group after 48 h was Enterococcus spp. (71.4%).

CONCLUSION

Both ertapenem and piperacillin-tazobactam were effective in the treatment of cUTIs caused by ESBL-producing microorganisms. A high frequency of superinfection in the ertapenem group was the result of Enterococcus and Pseudomonas spp., against which ertapenem is not active. In the presence of urinary catheterization, diabetes mellitus, and urological intervention, patients should be closely monitored for the development of a superinfection, especially patients receiving ertapenem.

Use of cefuroxime for women with community-onset acute pyelonephritis caused by cefuroxime-susceptible or -resistant Escherichia coli

BACKGROUND/AIMS

Efforts to decrease the use of extended-spectrum cephalosporins are required to prevent the selection and transmission of multi-drug resistant pathogens, such as extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. The objectives of this study were to assess the clinical efficacy of intravenous cefuroxime as an empirical antibiotic for the treatment of hospitalized women with acute pyelonephritis (APN) caused by Escherichia coli.

METHODS

We analyzed the clinical and microbiologic database of 328 hospitalized women with community-onset APN.

RESULTS

Of 328 women with APN, 22 patients had cefuroxime-resistant E. coli APN, and 306 patients had cefuroxime-susceptible E. coli APN. The early clinical success rates were significantly higher (p = 0.001) in the cefuroxime-susceptible group (90.8%, 278/306) than in the cefuroxime-resistant group (68.2%, 15/22) at 72 hours. The clinical cure rates at 4 to 14 days after completing antimicrobial therapy were not significantly different in the cefuroxime-resistant or -susceptible groups, with 88.2% (15/17) and 97.8% (223/228; p = 0.078), respectively. The microbiological cure rates were not significantly different and were 90.9% (10/11) and 93.4% (128/137), respectively (p = 0.550). The median duration of hospitalization in the cefuroxime-resistant and -susceptible groups was 10 days (interquartile range [IQR], 8 to 13) and 10 days (IQR, 8 to 14), respectively (p =0.319).

CONCLUSIONS

Cefuroxime, a second-generation cephalosporin, can be used for the initial empirical therapy of community-onset APN if tailored according to uropathogen identification and susceptibility results, especially in areas where the prevalence rate of ESBL-producing uropathogens is low.

Comparison of Second- and Third-Generation Cephalosporin as Initial Therapy for Women with Community-Onset Uncomplicated Acute Pyelonephritis

PURPOSE

This study examined the clinical effectiveness of parenteral cefuroxime and cefotaxime as empirical antibiotics for treating hospitalized women with uncomplicated acute pyelonephritis (APN).

MATERIALS AND METHODS

This study was based on the clinical and microbiologic data of 255 hospitalized women with APN. Of these 255 women, 144 patients received cefuroxime and 111 received cefotaxime.

RESULTS

There were no marked differences in the demographic features, clinical characteristics, and treatment duration between the populations of the cefuroxime and cefotaxime groups. The rates of defervescence showed no significant differences in the two groups at 48, 72, 96, and 120 hours. The clinical cure rates observed at the follow-up visit 4 to 14 days after the completion of antimicrobial therapy were not statistically different between the cefuroxime and cefotaxime groups [94.9% (129 of 136) versus 98.0% (100 of 102), respectively; p=0.307], and the microbiological cure rates were also not significantly different [88.3% (91 of 103) versus 95.0% (76 of 80), respectively; p=0.186]. The median hospitalization periods in the cefuroxime and cefotaxime groups were 7 (6-8) and 7 (6-8) days (p=0.157), respectively. Microbiological success rates after 72-96 hours of initial antimicrobial therapy were also not statistically different in the cefuroxime and cefotaxime groups, 89.4% (110 of 123) versus 94.9% (93 of 98; p=0.140).

CONCLUSION

Cefuroxime, a second-generation cephalosporin, is an appropriate antibiotic option for the initial treatment of uncomplicated APN and its efficacy does not differ from cefotaxime, a third-generation cephalosporin, in the initial parenteral therapy for community-onset APN.

Effects of gentamicin monotherapy for the initial treatment of community-onset complicated non-obstructive acute pyelonephritis due to Enterobacteriaceae in elderly and non-elderly women

Aminoglycosides may serve as fluoroquinolone-sparing or cephalosporin-sparing agents if the clinical effectiveness of aminoglycoside monotherapy is demonstrated. The purposes of this study were to investigate the clinical efficacy of gentamicin as an initial empirical antimicrobial agent and to evaluate the effects of gentamicin resistance on clinical outcomes in women with complicated non-obstructive acute pyelonephritis (APN). Medical records of 1066 women with a diagnosis of APN were reviewed retrospectively. We enrolled 275 women with community-onset complicated non-obstructive APN due to Enterobacteriaceae who received gentamicin as their initial antibiotic. Of these 275 patients, 43 had gentamicin-resistant (GM-R) Enterobacteriaceae APN, and 232 had gentamicin-susceptible (GM-S) Enterobacteriaceae APN. The early clinical success rates were 67.4% (29/43) versus 89.7% (208/232) at 72 h in the GM-R versus the GM-S groups (p 0.001). The overall clinical cure rate was 100% (43/43) and 98.7% (229/232) in the GM-R and GM-S groups, respectively. The duration of hospital stay was significantly longer in the elderly, although there were no significant differences in the rates of early clinical success, final clinical cure, mortality, and time to fever clearance between the elderly and non-elderly groups. Resistance of Enterobacteriaceae to gentamicin, haematuria and serum C-reactive protein level≥20 mg/dL were independently associated with early clinical failure. Gentamicin can be an effective initial antibiotic option for empirical therapy in women with community-onset complicated APN who do not need urological interventional procedures. The use of gentamicin may contribute to a reduction of fluoroquinolone or broad-spectrum cephalosporin use in the treatment of complicated APN.

A comparison of the clinical characteristics of elderly and non-elderly women with community-onset, non-obstructive acute pyelonephritis

BACKGROUND/AIMS

Acute pyelonephritis (APN) is the most common cause of community-onset bacteremia in hospitalized elderly patients. The objectives of this study were to investigate the differences in the clinical and microbiological data of hospitalized elderly and non-elderly women with community-onset APN.

METHODS

Women with community-onset APN as a discharge diagnosis were identified from January 2004 to December 2013 using an electronic medical records system. We compared the clinical and microbiologic data in elderly and non-elderly women with community-onset APN due to Enterobacteriaceae.

RESULTS

Of the 1,134 women with community-onset APN caused by Enterobacteriaceae, 443 were elderly and 691 were non-elderly women. The elderly group had a lower frequency of upper and lower urinary tract symptoms/signs than the non-elderly. The incidence of bacteremia, extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, patients with a C-reactive protein (CRP) level ≥ 15 mg/dL, and patients with a leukocyte count ≥ 15,000/mm(3) in the blood, were significantly higher in the elderly group than in the non-elderly group. The proportion of patients requiring hospitalization for 10 days or more was significantly higher in the elderly group compared to the non-elderly group (51.5% vs. 26.2%, p < 0.001). The clinical cure rates at 4 to 14 days after the end of therapy were 98.3% (338/344) and 97.4% (519/533) in the elderly and non-elderly groups, respectively (p = 0.393).

CONCLUSIONS

Elderly women with APN exhibit higher serum CRP levels, a higher frequency of bacteremia, a higher proportion of ESBL-producing uropathogens, and require a longer hospitalization than non-elderly women, although these patients may not complain of typical urinary symptoms.

Propensity-matched analysis to compare the therapeutic efficacies of cefuroxime versus cefotaxime as initial antimicrobial therapy for community-onset complicated nonobstructive acute pyelonephritis due to Enterobacteriaceae infection in women

This study was performed to compare the therapeutic efficacy of cefuroxime with that of cefotaxime as initial antimicrobial therapies in women with complicated nonobstructive acute pyelonephritis (APN) caused by Enterobacteriaceae infections. The clinical characteristics and outcomes of a cefuroxime-treated group (n = 156) were compared with those of a cefotaxime-treated group (n = 166). Of these 322 women, 90 from each group were matched by propensity scores. The defervescence rates were not significantly different in the cefuroxime and cefotaxime groups at 72 h after the start of antimicrobial therapy (81.1% versus 78.9%, P = 0.709). The clinical and microbiological cure rates during the follow-up visits that were 4 to 14 days after the end of the antimicrobial therapies were not significantly different in the cefuroxime versus cefotaxime groups, which were 97.8% (87/89) versus 97.8% (87/89) (P > 0.999) and 89.5% (68/76) versus 90.7% (68/75) (P = 0.807), respectively. The median hospital stay duration and the median times to defervescence in the cefuroxime versus cefotaxime groups were 8 days (interquartile range [IQR], 7 to 10 days) versus 9 days (IQR, 7 to 11 days), respectively, and 55 h (IQR, 37 to 70 h) versus 55 h (IQR, 35 to 69 h), respectively. Bacteremia, extended-spectrum-β-lactamase-producing Enterobacteriaceae, C-reactive protein levels of ≥ 15 mg/dl, and white blood cell counts of ≥ 15,000/mm(3) of blood had independent effects on the rates of early clinical failure. Our data suggest that the effects of cefuroxime are not different from those of cefotaxime when they are used as an initial antimicrobial treatments for community-onset complicated nonobstructive APN in women.

β-Lactam/β-lactamase inhibitors versus carbapenems for the treatment of sepsis: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Data on the relative efficacy of β-lactam/β-lactamase inhibitors (BL/BLIs) versus carbapenems are scant.

METHODS

This is a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing any BL/BLI versus any carbapenem for the treatment of sepsis. The primary outcome was all-cause mortality. A broad search was conducted with no restrictions on language, publication status or date. Two reviewers independently applied the inclusion criteria and extracted the data. Assessment of risk of bias was performed using the domain-based approach. Subgroup analyses were used to investigate heterogeneity and focus on patient groups more likely to harbour ESBL-positive bacteria. Risk ratios (RRs) with 95% CIs were calculated and pooled.

RESULTS

Thirty-one RCTs were included. There was no difference between BL/BLIs and carbapenems in terms of mortality (RR 0.98, 95% CI 0.79-1.20), without heterogeneity. No differences were observed with regard to clinical or microbiological failure and bacterial superinfections. The results were not affected by risk of bias. No differences were detected in the subgroups of patients with nosocomial infections, Gram-negative infections and neutropenic fever. Adverse events requiring discontinuation were more common with BL/BLIs, on account of an increased incidence of diarrhoea. However, Clostridium difficile-associated diarrhoea (RR 0.29, 95% CI 0.10-0.87) was more frequent with carbapenems and seizures were more frequent with imipenem (RR 0.21, 95% CI 0.05-0.93).

CONCLUSIONS

No differences in efficacy between BL/BLIs and carbapenems exist in RCTs including patient populations with a certain, albeit unknown, rate of ESBL-positive bacteria causing infections.

Comparison of the clinical characteristics of diabetic and non-diabetic women with community-acquired acute pyelonephritis: a multicenter study

OBJECTIVES

Purpose of this study was to compare clinical characteristics and treatment outcomes in diabetic and non-diabetic women with community-acquired APN (CA-APN).

METHODS

We prospectively collected and analyzed clinical data of women with CA-APN who attended 11 hospitals in South Korea from March 2010 to February 2012.

RESULTS

Of a total of 775 patients, 246 (31.7%) were diabetic and 529 (68.3%) non-diabetic. Fewer of the diabetic patients had flank pain (27.6% vs. 37.2% P = 0.009), symptoms of lower urinary tract infection (57.3% vs. 69.6% P = 0.001) and costovertebral angle tenderness (54.9% vs. 72.2% P < 0.001). However, more of them had C-reactive protein ≥20 mg/dL (40.7% vs. 27.4% P < 0.001), azotemia (29.3% vs. 13.4% P < 0.001) and bacteremia (53.7% vs. 38.2% P < 0.001). Final clinical failure rates and deaths did not differ between the two groups: 6.9% vs. 4.5%, P = 0.169; 2.0% vs. 1.7%, P = 0.747. However, hospitalization was longer in the diabetics than the non-diabetics (median 9.0 days vs. 7.0 days, P < 0.001). In logistic regression, diabetes was independently associated with longer hospitalization (OR 1.7, CI 1.1-2.7, P = 0.011), together with nausea/vomiting, history of admission within 1 year, bacteremia, azotemia, and dementia, as well as extended-spectrum β-lactamase (ESBL)-positivity and fluoroquinolone resistance of uropathogens.

CONCLUSIONS

CA-APN patients with diabetes have more severe disease manifestations and require longer hospitalization than non-diabetic patients although their clinical findings are less clear than those of non-diabetic patients.

Clinical characteristics predicting early clinical failure after 72 h of antibiotic treatment in women with community-onset acute pyelonephritis: a prospective multicentre study

In patients with community-onset acute pyelonephritis (CO-APN), assessing the risk factors for poor clinical response after 72 h of antibiotic treatment (early clinical failure) is important. The objectives of this study were to define those risk factors, and to assess whether early clinical failure influences mortality and treatment outcomes. We prospectively collected the clinical and microbiological data of women with CO-APN in South Korea from March 2010 to February 2012. The numbers of cases in the early clinical success and early clinical failure groups were 840 (79.1%) and 222 (20.9%), respectively. Final clinical failure and mortality were higher in the early clinical failure group than in the early clinical success group (14.9% vs 2.3%, p <0.001; 6.8% vs 0.1%, p 0.001, respectively). In a multiple logistic regression model, the risk factors for early clinical failure among the total 1062 patients were diabetes mellitus (OR 1.5; 95% CI 1.1-2.1), chronic liver diseases (OR 3.3; 95% CI 1.6-6.7), malignancy (OR 2.2; 95% CI 1.1-4.4), Pitt score ≥2 (OR 2.5; 95% CI 1.6-3.8), presence of azotaemia (OR 1.8; 95% CI 1.2-2.7), white blood cell count ≥20 000/mm(3) (OR 2.5; 95% CI 1.6-4.0), serum C-reactive protein level ≥20 mg/dL (OR 1.7; 95% CI 1.2-2.4), and history of antibiotic usage within the previous year (OR 1.5; 95% CI 1.1-2.2). Analysing the subgroup of 743 patients with CO-APN due to Enterobacteriaceae, fluoroquinolone resistance of the uropathogen was another factor associated with early clinical failure (OR 1.7; 95% CI 1.1-2.5). Simple variables of underlying diseases, previous antibiotic usage and initial laboratory test outcomes can be used to decide on the direction of treatment in CO-APN.

Systematic review and meta-analysis of antimicrobial treatment effect estimation in complicated urinary tract infection

Noninferiority trial design and analyses are commonly used to establish the effectiveness of a new antimicrobial drug for treatment of serious infections such as complicated urinary tract infection (cUTI). A systematic review and meta-analysis were conducted to estimate the treatment effects of three potential active comparator drugs for the design of a noninferiority trial. The systematic review identified no placebo trials of cUTI, four clinical trials of cUTI with uncomplicated urinary tract infection as a proxy for placebo, and nine trials with reports of treatment effect estimates for doripenem, levofloxacin, or imipenem-cilastatin. In the meta-analysis, the primary efficacy endpoint of interest was the microbiological eradication rate at the test-of-cure visit in the microbiological intent-to-treat population. The estimated eradication rates and corresponding 95% confidence intervals (CI) were 31.8% (26.5% to 37.2%) for placebo, 81% (77.7% to 84.2%) for doripenem, 79% (75.9% to 82.2%) for levofloxacin, and 80.5% (71.9% to 89.1%) for imipenem-cilastatin. The treatment effect estimates were 40.5% for doripenem, 38.7% for levofloxacin, 34.7% for imipenem-cilastatin, and 40.8% overall. These treatment effect estimates can be used to inform the design and analysis of future noninferiority trials in cUTI study populations.

Antibiotic treatment of uncomplicated urinary tract infection in premenopausal women

Uncomplicated urinary tract infections (UTIs) in otherwise healthy premenopausal women are one of the most frequent infections in the community. Therefore any improvement in management will have a high impact not only on the quality of life of the individual patient but also on the health system. In placebo-controlled studies antimicrobial treatment was significantly more effective than placebo, but on the other hand showed more adverse events. The choice of antibiotic depends on the spectrum and susceptibility patterns of the uropathogens, its effectiveness for this indication, its tolerability, its collateral effects and cost. After a systematic literature search, recommendations for empiric treatment of acute uncomplicated cystitis and acute uncomplicated pyelonephritis and for follow-up strategies were developed.

Complicated urinary tract infection in adults

BACKGROUND

Complicated urinary tract infection occurs in individuals with functional or structural abnormalities of the genitourinary tract.

OBJECTIVE

To review current knowledge relevant to complicated urinary tract infection, and to provide evidence-based recommendations for management.

METHODS

The literature was reviewed through a PubMed search, and additional articles were identified by journal reference review. A draft guideline was prepared and critically reviewed by members of the Association of Medical Microbiology and Infectious Disease Canada Guidelines Committee, with modifications incorporated following the review.

RESULTS

Many urological abnormalities may be associated with complicated urinary infection. There is a wide spectrum of potential infecting organisms, and isolated bacteria tend to be more resistant to antimicrobial therapy. Morbidity and infection outcomes in subjects with complicated urinary infection are principally determined by the underlying abnormality rather than the infection. Principles of management include uniform collection of a urine specimen for culture before antimicrobial therapy, characterization of the underlying genitourinary abnormality, and nontreatment of asymptomatic bacteriuria except before an invasive genitourinary procedure. The antimicrobial regimen is determined by clinical presentation, patient tolerance, renal function and known or anticipated infecting organisms. If the underlying abnormality contributing to the urinary infection cannot be corrected, then early post-treatment recurrence of infection is anticipated.

CONCLUSIONS

The management of complicated urinary infection is individualized depending on patient variables and the infecting organism. Further clinical investigations are necessary to assist in determining optimal antimicrobial regimens.

An update on uncomplicated urinary tract infections in women

PURPOSE OF REVIEW

Urinary tract infections (UTIs) in women comprise uncomplicated and complicated UTIs. Uncomplicated UTIs, such as acute uncomplicated cystitis and pyelonephritis, are very common infections in otherwise healthy women, with a high tendency to recur. Although severe complications are rare, their high prevalence causes remarkable costs in the healthcare systems.

RECENT FINDINGS

As most scientific evidence has been gathered in uncomplicated UTI, this study focuses on recent developments in epidemiology, pathogenesis, cause, diagnosis, treatment and prevention of uncomplicated UTI and recurrent UTI in women.

SUMMARY

A remarkable increase of antibiotic resistance is also noted in uncomplicated UTI. Therefore, prudent use of antibiotic substances in uncomplicated UTI is increasingly important.

Carbapenems versus other beta-lactams in treating severe infections in intensive care: a systematic review of randomised controlled trials

Carbapenems have not been comprehensively compared in clinical trials with fourth-generation cephalosporins (4GC) and antipseudomonal penicillins (APP) in the treatment of severe infections (SI) and febrile neutropenia (FN). A systematic review of CENTRAL, EMBASE, MEDLINE and JICST-EPlus for randomised controlled trials was conducted to establish the currently available evidence. Database searching was supplemented by hand searching and contacting conference organisers. Searching was completed in November 2006 and no restriction was placed on the language of publication. Data were extracted on clinical response, bacteriologic response, all-cause mortality and adverse events. Of the 265 papers identified, 12 were appropriate for meta-analysis (four 4GC and eight APP). The results showed that carbapenems are associated with a significant reduction in all-cause mortality (relative risk 0.62, 95% confidence interval: 0.41 to 0.95; p=0.03) compared to APP in the treatment of SI, and withdrawals due to adverse events (RR 0.65, 95% CI: 0.45 to 0.96; p=0.03) are also less common. When compared in the treatment of FN, carbapenems are associated with a significant increase in clinical response during the initial 72 h of treatment (RR 1.37, 95% CI: 1.09 to 1.74; p=0.008) and bacteriologic response (RR 1.73, 95% CI: 1.03 to 2.89; p=0.04). For all other outcomes, including all comparisons with 4GC, there were no significant differences between treatments. The use of carbapenems rather than APP could reduce mortality and, by simplifying treatment decisions, reduce the time before patients receive appropriate antibiotic treatment. The currently available evidence is insufficient for distinguishing between carbapenems and 4GC.

Comparative Review of the Carbapenems

The carbapenems are beta-lactam antimicrobial agents with an exceptionally broad spectrum of activity. Older carbapenems, such as imipenem, were often susceptible to degradation by the enzyme dehydropeptidase-1 (DHP-1) located in renal tubules and required co-administration with a DHP-1 inhibitor such as cilastatin. Later additions to the class such as meropenem, ertapenem and doripenem demonstrated increased stability to DHP-1 and are administered without a DHP-1 inhibitor. Like all beta-lactam antimicrobial agents, carbapenems act by inhibiting bacterial cell wall synthesis by binding to and inactivating penicillin-binding proteins (PBPs). Carbapenems are stable to most beta-lactamases including AmpC beta-lactamases and extended-spectrum beta-lactamases. Resistance to carbapenems develops when bacteria acquire or develop structural changes within their PBPs, when they acquire metallo-beta-lactamases that are capable of rapidly degrading carbapenems, or when changes in membrane permeability arise as a result of loss of specific outer membrane porins. Carbapenems (imipenem, meropenem, doripenem) possess broad-spectrum in vitro activity, which includes activity against many Gram-positive, Gram-negative and anaerobic bacteria; carbapenems lack activity against Enterococcus faecium, methicillin-resistant Staphylococcus aureus and Stenotrophomonas maltophilia. Compared with imipenem, meropenem and doripenem, the spectrum of activity of ertapenem is more limited primarily because it lacks activity against Pseudomonas aeruginosa and Enterococcus spp. Imipenem, meropenem and doripenem have in vivo half lives of approximately 1 hour, while ertapenem has a half-life of approximately 4 hours making it suitable for once-daily administration. As with other beta-lactam antimicrobial agents, the most important pharmacodynamic parameter predicting in vivo efficacy is the time that the plasma drug concentration is maintained above the minimum inhibitory concentration (T>MIC). Imipenem/cilastatin and meropenem have been studied in comparative clinical trials establishing their efficacy in the treatment of a variety of infections including complicated intra-abdominal infections, skin and skin structure infections, community-acquired pneumonia, nosocomial pneumonia, complicated urinary tract infections, meningitis (meropenem only) and febrile neutropenia. The current role for imipenem/cilastatin and meropenem in therapy remains for use in moderate to severe nosocomial and polymicrobial infections. The unique antimicrobial spectrum and pharmacokinetic properties of ertapenem make it more suited to treatment of community-acquired infections and outpatient intravenous antimicrobial therapy than for the treatment of nosocomial infections. Doripenem is a promising new carbapenem with similar properties to those of meropenem, although it appears to have more potent in vitro activity against P. aeruginosa than meropenem. Clinical trials are required to establish the efficacy and safety of doripenem in moderate to severe infections, including nosocomial infections.

Antibiotic treatment for acute 'uncomplicated' or 'primary' pyelonephritis: a systematic, 'semantic revision'

The definition of acute pyelonephritis is controversial. There are two contrasting approaches: (1) acute pyelonephritis is a severe infectious disease involving the kidney parenchyma, and specific imaging techniques are required for diagnosis; (2) acute pyelonephritis is a urinary tract infection, and diagnosis and therapy follow simplified clinical and laboratory pathways. In this study, recent randomized controlled trials (RCTs) were systematically reviewed and the diagnostic and therapeutic approaches to acute 'uncomplicated' pyelonephritis were analysed. Medline, Embase, Cochrane Central Register of Controlled Trials (CCTR) and Chinal were searched employing Mesh, Emtree and free terms on 'pyelonephritis'. Limits included human, period (1995-2004), and trials-reviews (where available). In total, 904 references and 175 full-text were retrieved; 29 were pertinent RCTs. Seven RCTs were added from reference lists (indexed on urinary tract infections). Imaging examinations were performed in 11 of 14 studies on children (diagnostic requisite in two) and in two studies on adults; scarring was not analysed in adults. Clinical definitions varied widely (fever >37.8 to >39 degrees C, culture titres 10(4) >10(5)). Studies on adults were limited to short-term end-points (microbiological sterilization, clinical improvement). Duration of therapy was 4-20 days. The trend was towards shorter periods of therapy, mainly on an outpatient basis; intravenous therapy, if performed, was usually limited to the first 1-3 days. For acute uncomplicated pyelonephritis, the tendency is towards 2 weeks of mainly oral antibiotic therapy. However, the recent literature on adults does not discriminate among different upper urinary tract infections nor does it provide data on renal scarring. While cost constraints point towards short-term therapies, further studies are needed to assess the prevalence and long-term effect of kidney scars.