Spectrum and antibiotic resistance of uropathogens from hospitalized patients with urinary tract infections: 1994-2000

Exploring the Dynamic Role of Bacterial Etiology in Complicated Urinary Tract Infections

Background and Objectives. Numerous studies have been conducted to explore the epidemiological characteristics of urinary tract infections (UTI) and sepsis. However, there is still a lack of relevant bacteriological features and prognostic information regarding urosepsis based on bacteriological etiology. The current study aims to evaluate the bacterial etiology of complicated UTI (cUTI) and bacterial resistance to antibiotics and whether they present an intrinsic risk of developing urosepsis. Materials and Methods. A retrospective study was performed that included 102 patients who were diagnosed with cUTI and admitted to the urology department of the "Sfântul Apostol Andrei" County Emergency Clinical Hospital (GCH) from September 2019 to May 2022. Results. A considerable number of patients, n = 41 (40.2%), were diagnosed with multi drug-resistant (MDR) infection. Escherichia coli (E. coli) was identified as the prevailing pathogen, accounting for 51 patients. Klebsiella manifested itself as the subsequent causative agent in 27 instances. The presence of Enterococcus spp. infection was documented in 13 patients, whereas Pseudomonas emerged as the etiological perpetrator in the clinical context of 8 patients. The current study found a substantial prevalence of resistance to first-line antibiotics. The overall resistance rate was 74.5% for penicillin, 58.82% for trimethoprim-sulfamethoxazole and 49% for fluoroquinolones; cephalosporin resistance displayed an inverse correlation with antibiotic generation with fourth-generation cephalosporins exhibiting a resistance rate of 24.5%, and first-generation cephalosporins demonstrating a resistance rate of 35.29%. Conclusions. Age, comorbidities and indwelling urinary catheters are risk factors for developing MDR infections. While the intrinsic characteristics of the causative bacterial agent in cUTI may not be a risk factor for developing urosepsis, they can contribute to increased mortality risk. For empiric antibiotic treatment in patients with cUTI who are at a high risk of developing urosepsis and experiencing a potentially unfavorable clinical course, broad-spectrum antibiotic therapy is recommended. This may include antibiotics, such as amikacin, tigecycline, carbapenems and piperacillin-tazobactam.

Phenotypic and Molecular Detection of BlaNDM Gene Among Drug-Resistant Klebsiella Isolates

BACKGROUND

In the past few centuries, a widespread increase in antimicrobial resistance has been observed among Klebsiella species. The antibiotic- resistant strains of the genus Klebsiella are becoming a serious threat in clinical settings due to their involvement in severe invasive and non-invasive infections. The emergence of resistance among these strains is associated with their strong enzymatic activity against several broad-spectrum antibiotics. These enzymes include beta-lactamases, extended-spectrum beta-lactamases (ESBL), AmpC beta-lactamases, and carbapenemases. These resistance enzymes are capable of hydrolyzing various broad-spectrum drugs like extended-spectrum cephalosporin and carbapenems.

OBJECTIVE

The present study was conducted to determine the emerging resistance among Klebsiella strains by identifying the production of carbapenemase enzyme phenotypically and the frequency of the NDM resistance gene by a polymerase chain reaction.

METHODS

In this study, 236 Gram-negative isolates from different clinical laboratories were identified. Out of which, 125 isolates were found as Klebsiella species by using standard microbiological techniques. Minimum inhibitory concentrations (MIC) were determined using eight representative antibiotics by the Macro broth dilution method. Phenotypic detection of carbapenemase producing Klebsiella species was performed by Modified Hodge Test. Phenotypic findings were then checked and compared with genotypic results obtained by using the Polymerase chain reaction (PCR) for the detection of resistance genes responsible for the production of carbapenemase.

RESULTS

In this study, carbapenemase production was found only in 6 (5%) Klebsiella isolates by using the phenotypic method; however, 3 isolates out of 125 were screened positive for the gene NDM-1.

CONCLUSION

Since we are considering carbapenems as the last therapeutic option for treating infections, mainly caused by Gram-negative isolates, the prevailing resistance against this drug is widely disseminating. It is better to evaluate the antibiotic susceptibility, phenotypic screening as well genotypic screening (where possible) for implementing strict antibiotic control policies in health care settings, hospitals, laboratories, etc.

Antibiotic resistance in E. coli isolates from patients with urinary tract infections presenting to the emergency department

PURPOSE

Escherichia coli urine isolates from patients presenting to the emergency department at a German tertiary care hospital were retrospectively analyzed from January 2015-March 2017 to determine antibiotic resistance patterns and patient risk factors for resistance.

METHODS

Uncomplicated urinary tract infection (UTI) was defined as UTI in the otherwise healthy patient without relevant co-morbidities and complications. Patients were assumed to have UTI if diagnosis was made by the attending physician with conclusive dipstick results. For subgroup analysis, only patients with symptoms suggestive for UTI documented in their records were included.

RESULTS

228 patients with a UTI diagnosed by the attending physician with E. coli isolated in urine culture were included. 154/228 patients had documented symptomatic UTI, 57/154 had uncomplicated infection, 76/154 patients had cystitis, and 124/154 were female. Resistance rates of uncomplicated UTI in symptomatic patients were: ciprofloxacin 10.5%, cotrimoxazole 15.8%, amoxicillin/clavulanic acid 5.3%, nitrofurantoin 0% (CLSI MICs). Previous hospitalization in the last 3 months (including patients living in a long-term care facility) was significantly correlated with resistance to ciprofloxacin, cotrimoxazole and amoxicillin/clav. Previous hospitalization was a strong predictor of resistance to ciprofloxacin and cotrimoxazole in multivariate analysis also. Other risk factors correlated with resistance were hematological malignancy (for cotrimoxazole) and renal transplantation (for ciprofloxacin).

CONCLUSIONS

Cotrimoxazole is still an alternative for treating uncomplicated cystitis. Previous hospitalization in the last 3 months was a strong predictor of resistance to cotrimoxazole and ciprofloxacin. Other risk factors which might help guide empirical therapy are hematological malignancy and renal transplantation.

The Ciprofloxacin Impact on Biofilm Formation by Proteus Mirabilis and P. Vulgaris Strains

BACKGROUND

Proteus spp. bacilli belong to opportunistic human pathogens, which are primarily responsible for urinary tract and wound infections. An important virulence factor is their ability to form biofilms that greatly reduce the effectiveness of antibiotics in the site of infection.

OBJECTIVES

The aim of this study was to determine the value of the minimum concentration of ciprofloxacin that eradicates a biofilm of Proteus spp. strains.

MATERIALS AND METHODS

A biofilm formation of 20 strains of P. mirabilis and 20 strains of P. vulgaris were evaluated by a spectrophotometric method using 0.1% 2, 3, 5-Triphenyl-tetrazolium chloride solution (TTC, AVANTORTM). On the basis of the results of the absorbance of the formazan, a degree of reduction of biofilm and minimum biofilm eradication (MBE) values of MBE50 and MBE90 were determined.

RESULTS

All tested strains formed a biofilm. A value of 1.0 μg/mL ciprofloxacin is MBE50 for the strains of both tested species. An MBE90 value of ciprofloxacin for isolates of P. vulgaris was 2 μg/mL and for P. mirabilis was 512 μg/mL.

CONCLUSIONS

Minimum biofilm eradication values of ciprofloxacin obtained in the study are close to the values of the minimal inhibition concentration (MIC).

The emerging threat of multidrug-resistant Gram-negative bacteria in urology

Antibiotic resistance in Gram-negative uropathogens is a major global concern. Worldwide, the prevalence of Enterobacteriaceae that produce extended-spectrum β-lactamase or carbapenemase enzymes continues to increase at alarming rates. Likewise, resistance to other antimicrobial agents including aminoglycosides, sulphonamides and fluoroquinolones is also escalating rapidly. Bacterial resistance has major implications for urological practice, particularly in relation to catheter-associated urinary tract infections (UTIs) and infectious complications following transrectal-ultrasonography-guided biopsy of the prostate or urological surgery. Although some new drugs with activity against Gram-negative bacteria with highly resistant phenotypes will become available in the near future, the existence of a single agent with activity against the great diversity of resistance is unlikely. Responding to the challenges of Gram-negative resistance will require a multifaceted approach including considered use of current antimicrobial agents, improved diagnostics (including the rapid detection of resistance) and surveillance, better adherence to basic measures of infection prevention, development of new antibiotics and research into non-antibiotic treatment and preventive strategies.

Antibiotic treatment for urinary tract infections: pharmacokinetic/pharmacodynamic principles

Bacterial urinary tract infections (UTIs) frequently occur in the outpatient as well as in the nosocomial setting. The stratification into uncomplicated and complicated UTIs has proven to be clinically useful. Bacterial virulence factors on the one hand, and the integrity of the host defense mechanisms on the other, determine the course of the infection. Late complications or sequelae might ensue if the defense mechanisms are disturbed, either by a genetic or an acquired cause. Escherichia coli is the most prevalent organism in uncomplicated UTIs, whereas the bacterial spectrum is much broader in complicated UTIs, including Gram-negative and -positive, and often multiresistant organisms. Therapy for uncomplicated UTIs is almost exclusively antibacterial, whereas in complicated UTIs the complicating factors need to be treated as well. The success of antibiotic therapy of UTIs in a population can be estimated by four parameters: the minimal inhibitory concentrations of the clinical isolates, the pharmacokinetic and pharmacodynamic profiles, and the protein binding of the treatment drug. In uncomplicated UTIs, antimicrobial therapy is usually empiric, whereas in complicated UTIs antibiotic therapy should be more individualized; tailored to the individual patient.

The prevalence, etiologic agents and risk factors for urinary tract infection among spinal cord injury patients

BACKGROUND

Urinary tract infections (UTIs) are important causes of morbidity and mortality in patients with spinal cord injury and 22% of patients with acute spinal cord injury develop UTI during the first 50 days.

OBJECTIVES

The aim of this study was to determine the prevalence, etiologic agents and risk factors for asymptomatic bacteriuria and symptomatic urinary tract infections in patients with spinal cord injury.

PATIENTS AND METHODS

This was a prospective investigation of spinal cord injury patients with asymptomatic bacteriuria and symptomatic urinary tract infections in Baskent University Medical Faculty Ayas Rehabilitation Center and Ankara Physical Therapy and Rehabilitation Center between January 2008 and December 2010. The demographic status, clinical and laboratory findings of 93 patients with spinal cord injury were analyzed in order to determine the risk factors for asymptomatic or symptomatic bacteriuria.

RESULTS

Sixty three (67.7%) of 93 patients had asymptomatic bacteriuria and 21 (22.6%) had symptomatic urinary tract infection. Assessment of the frequency of urinary bladder emptying methods revealed that 57 (61.3%) of 93 patients employed permanent catheters and 24 (25.8%) employed clean intermittent catheterization. One hundred and thirty-five (48.0%) of 281 strains isolated form asymptomatic bacteriuria attacks and 16 (66.6%) of 24 strains isolated from symptomatic urinary tract infection attacks, totaling 151 strains, had multidrug resistance (P > 0.05). One hundred (70.4%) of 142 Escherichia coli strains and 19 (34.5%) of 55 Klebsiella spp strains proliferated in patients with asymptomatic bacteriuria; 8 (80%) of 10 E. coli strains and 4 (80%) of 5 Klebsiella spp. strains were multidrug resistant.

CONCLUSIONS

The most common infectious episode among spinal cord injury patients was found to be urinary tract ınfection. E. coli was the most common microorganism isolated from urine samples. Antibiotic use in the previous 2 weeks or 3 months, hospitalization during the last one-year and previous diagnosis of urinary tract ınfection were the risk factors identified for the development of infections with multi-drug resistant isolates. Urinary catheterization was found to be the only independent risk factor contributing to symptomatic urinary tract infection.

The assessment of Proteus mirabilis susceptibility to ceftazidime and ciprofloxacin and the impact of these antibiotics at subinhibitory concentrations on Proteus mirabilis biofilms

Rods of the Proteus genus are commonly isolated from patients, especially from the urinary tracts of the catheterised patients. The infections associated with biomaterials are crucial therapeutic obstacles, due to the bactericidal resistance of the biofilm. The aim of this study was to assess the susceptibility of P. mirabilis planktonic forms to ciprofloxacin and ceftazidime, the ability to form biofilm, and the impact of chosen sub-MIC concentrations of these antibiotics on biofilm at different stages of its formation. The research included 50 P. mirabilis strains isolated from wounds and the urinary tracts from patients of the University Hospital No. 1 in Bydgoszcz. The assessment of susceptibility to ciprofloxacin and ceftazidime was conducted using micromethods. The impact of sub-MIC concentrations of the chosen antibiotics on the biofilm was measured using the TTC method. The resistance to ciprofloxacin was confirmed for 20 strains (40.0%) while to ceftazidime for 32 (64.0%) of the tested P. mirabilis strains. All of the tested strains formed biofilm: 24.0% weakly, 26.0% moderately, and 50.0% strongly. It was determined that ciprofloxacin and ceftazidime caused eradication of the biofilm. Moreover, the connection between origin of the strains, biofilm maturity level, and resistance to antibiotics was proved.

Resistance patterns of nosocomial urinary tract infections in urology departments: 8-year results of the global prevalence of infections in urology study

OBJECTIVE

To present the worldwide antibiotic resistance rates of uropathogens reported in nosocomial urinary tract infections (NAUTI) during the period of 2003-2010.

MATERIALS AND METHODS

Data from the Global Prevalence Study of Infections in Urology from the period of 2003-2010 were analyzed to evaluate the resistance rates of pathogens causing NAUTI. The web-based application was used to record data of investigators from urology departments participating in the study every year during the days allocated in November. Each center was allowed to enter data on a single day of the study. The point prevalence data was used to find differences among geographic regions and years by utilizing multiple logistic regression analysis.

RESULTS

A total of 19,756 patients were hospitalized during the study period, and in 1,866 of them, NAUTI was reported. Proof of infection was reported in 1,395 patients. Resistance rates of all antibiotics tested other than imipenem against the total bacterial spectrum were higher than 10 % in all regions. Resistance to almost all pathogens was lowest in North Europe, and there is no single year where an outbreak of resistance has been detected.

CONCLUSION

The resistance rates of most of the uropathogens against the antibiotics tested did not show significant trends of increase or decrease with Asia exhibiting the highest rates in general. The only antibiotic tested with an overall resistance rate below 10 % was imipenem. Knowledge of regional and local resistance data and prudent use of antibiotics are necessary to optimize antibiotic therapy in urological patients with NAUTI.

Relationship between urinary tract infection categorization and pathogens' antimicrobial susceptibilities

BACKGROUND

Urinary tract infections (UTIs) can be hard to treat and treatment plans need to include accurate categorization such as uncomplicated or complicated UTI, or catheterized or uncatheterized UTI. We investigated the antibiotic susceptibilities of representative uropathogens in UTI categories.

METHODS

We isolated uropathogens and analyzed their antimicrobial susceptibilities according to UTI categorization such as: (1) urology outpatients, urology inpatients, or other department inpatients; (2) uncomplicated or complicated UTIs; (3) upper or lower UTIs, and (4) non-catheterized or catheterized UTIs.

RESULTS

Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa were representative uropathogens. Susceptibilities to levofloxacin (LVFX) in E. coli in urology outpatients (p = 0.0179), those to ceftadizime in E. coli in other department inpatients (p = 0.0327), and those to LVFX in E. faecalis in complicated UTI (p = 0.0137) significantly decreased in these 3 years compared with the previous 3 years. Susceptibilities of upper UTI to LVFX in E. coli were significantly lower in the recent 4 years compared to lower UTI (p = 0.0452) and those of catheterized UTI to LVFX in E. faecalis were significantly lower than in non-catheterized UTI (p = 0.0153).

CONCLUSIONS

Data demonstrated different tendencies of uropathogens' antibiotic susceptibilities according to UTI categorizations and they could be useful for planning UTI treatments.

Antimicrobials in urogenital infections

Urinary tract infections (UTIs) and male genital infections are amongst the most prevalent infections. A prudent antibiotic policy therefore has a large impact on society. The clinical classification in uncomplicated cystitis, uncomplicated pyelonephritis, complicated UTI and genital infections is useful, also for the right choice of antibiotic treatment. In this regard pharmacokinetic and pharmacodynamic aspects have to be considered. Nowadays in uncomplicated cystitis antibiotics exclusively reserved for this indication are preferred, such as fosfomycin trometamol, nitrofurantoin and pivmecillinam, in order to reduce antibiotic pressure in this extremely frequent entity. In complicated UTI a broad bacterial spectrum has to be considered. Different antibiotic substances should be used for treatment, such as penicillins, with β-lactamase inhibitors, cephalosporins or carbapenems, fluoroquinolones, aminoglycosides or cotrimoxazole, if tested susceptible. For genital infections the pharmacokinetic properties of the antibiotics should especially be considered, such as in prostatitis, where mainly fluoroquinolones and macrolides show sufficient pharmacokinetic parameters for treatment of bacterial infections. Furthermore in genital infections fastidious organisms, such as Chlamydia or Mycoplasma spp. have to be considered with respect to their antimicrobial susceptibility.

Acute pyelonephritis: clinical characteristics and the role of the surgical treatment

The epidemiology of acute pyelonephritis (APN) has changed with time. Therefore we investigated the current clinical characteristics of APN and the significance of proper surgical management for treatment of 1,026 APN patients in South Korea for the past 5 yr. The male-to-female ratio was about 1:8. The peak ages of female patients were 20s (21.3%) and over 60s (23.7%), while that of male was over 60s (38.1%). The occurrence of sepsis was 10.1%. Complicated APN patients were 35.4%. Ninety-four patients (9.2%) needed urological procedures. The duration of the flank pain and of the costovertebral angle tenderness in complicated APN patients was statistically significantly longer than that with simple APN patients (4.3 vs. 3.4 days, 4.4 vs. 4.0 days). If flank pain and costovertebral angle tenderness sustain over 4 days, proper radiologic studies should be performed immediately with the consideration of surgical procedure. Also the resistance to antibiotics was increasing. As the sensitivities to ampicillin (27.2%) and trimethoprim/sulfamethoxazole (44.7%) of Escherichia coli and Klebsiella pneumoniae were very low, it is necessary to take the careful choice of antibiotics into consideration.

[Nosocomial urinary tract infections in the geriatric hospital - pathogen spectrum and resistancies]

We examined 834 isolates of urinary cultures (26 fungi and 808 isolates from 28 bacteria) in an academic geriatric teaching hospital for microbial spectrum and resistance analysis. Of the bacteria, 90% were associated to ten species. Detection rate of MRSA and ESBL was 1%, detection rate for pseudomonas aeruginosa, proteus species, coagulase negative staphylococci and klebsiella species were higher than in an university clinic (p < 0.001). Resistency rates were high for the 10 most frequent bacteria: 53.3% of cross-tabulations between bacterium and antibiotic agent (sulfamethoxazol-trimethoprim, amoxicillin-clavulanate, ciprofloxacin, moxifloxacin, cefuroxim, imipenem) showed resistency rate higher than 10%. We assume that specific factors of geriatric sample taking have an impact to our 2-year resistogram results. It is necessary to combine data analysis from comprehensive geriatric assessment and microbiological methods.

A prospective randomized and placebo-controlled study for the evaluation of antibiotic prophylaxis in transurethral resection of the prostate

AIM

To evaluate the risk of bacteriuria after transurethral resection of the prostate and the preventive effects of different kinds of antibiotics.

PATIENTS AND METHODS

Urine was collected for culturing 1 week before the operation and on postoperative days 2 and 10. The patients were divided into four groups: group 1 patients were given a first-generation cephalosporin (cefazolin 1 g), group 2 patients received a second-generation cephalosporin (cefuroxime 750 mg), group 3 patients were given a third-generation cephalosporin (ceftazidime 1 g), and group 4 patients received a placebo.

RESULTS

The 2nd-day postoperative bacteriuria rates were similar in all groups. On the 10th day, the incidence rates of bacteriuria in group 4 and group 1 patients were 40 and 31%, respectively (p = 0.661). In group 2, the bacteriuria incidence rate was 6.6%, and when compared with the placebo group, the difference was considered significant (p = 0.002). The difference between group 3 and group 4 was also significant (p = 0.003). There were statistically significant differences between group 1 and group 2 (p = 0.008) and between group 1 and group 3 (p = 0.01).

CONCLUSIONS

Our study demonstrated that postoperative bacteriuria incidence rates are high, even in patients who underwent transurethral resection of the prostate with sterile urine, but it can be reduced by using antibiotic prophylaxis with cefuroxime or ceftazidime.

[Nosocomial urinary tract infection in adults]

Urinary tract infection (UTI) is the most common infection in hospitalized adults. Nosocomial UTIs are mainly associated with the use of urinary catheters. Thus, the decision for catheterization should be made carefully and catheters removed in time. In order to prevent unnecessary antibiotic use in patients with urinary catheters correct diagnosis is crucial. Chinolones, broad-spectrum penicillins and third-generation cephalosporins are the mainstay of therapy. Comorbidities should be considered and potential obstructions of urinary flow removed. Economically important are the normally higher prices of i.v. antibiotics compared to oral use.

Concentrations in plasma, urinary excretion and bactericidal activity of levofloxacin (500mg) versus ciprofloxacin (500mg) in healthy volunteers receiving a single oral dose

In a randomised crossover study, 14 volunteers received a single oral dose of 500 mg levofloxacin or 500 mg ciprofloxacin in order to assess plasma concentrations by high-pressure liquid chromatography (up to 24 h), urinary excretion and urinary bactericidal titres (UBTs) at intervals up to 120 h. The median maximum concentration of levofloxacin in plasma was 6.1 mg/L and that of ciprofloxacin was 2.3 mg/L. The median cumulative level of renal excretion of the administered dose of the parent drug was 81.2% for levofloxacin and 36.2% for ciprofloxacin. UBTs were determined for a reference strain and nine clinical uropathogens. The median UBTs of both quinolones measured within the first 12h were between 0 and 1:> or =1024, correlating with the minimum inhibitory concentrations (MICs) of the strains. For Gram-negative strains, the UBTs of both quinolones were comparable despite the lower MICs of ciprofloxacin. During further time courses, however, the UBTs of levofloxacin were significantly higher than those of ciprofloxacin. For Gram-positive strains, for which the MICs of levofloxacin were equal to or lower than those of ciprofloxacin, the UBTs of levofloxacin were already significantly higher from the beginning. It can be concluded that overall the doses of the two tested fluoroquinolones may be considered equivalent with regard to treatment of complicated urinary tract infections, although the recommended dosing is twice daily for ciprofloxacin and once daily for levofloxacin.

Urinary bactericidal activity of extended-release ciprofloxacin (1,000 milligrams) versus levofloxacin (500 milligrams) in healthy volunteers receiving a single oral dose

Twelve volunteers received a single oral dose of 1,000 mg extended-release (XR) ciprofloxacin versus 500 mg levofloxacin to assess urinary bactericidal titers (UBTs) against common uropathogens. Areas under UBT-time curves were significantly larger for Proteus mirabilis with XR ciprofloxacin and for staphylococci with levofloxacin.

Pharmacokinetics of ciprofloxacin XR (1000mg) versus levofloxacin (500mg) in plasma and urine of male and female healthy volunteers receiving a single oral dose

The new extended-release formulation of ciprofloxacin (ciprofloxacin XR) was designed for once-daily administration in the treatment of urinary tract infection (UTI). The aim of this study was to compare concentrations in plasma, urinary excretion (UE) and pharmacokinetic parameters of ciprofloxacin XR (1000 mg) versus those of levofloxacin (500 mg) in healthy volunteers receiving a single oral dose. In this randomised crossover study, 12 volunteers (6 males, 6 females) received a single oral dose of 1000 mg ciprofloxacin XR or 500 mg levofloxacin to assess the concentrations (by high-pressure liquid chromatography) in plasma up to 32 h and the UE at intervals up to 36 h. The following pharmacokinetic parameters were studied: C(max), t(max), t(1/2), AUC(plasma0-->infinity), AUC(plasma0-->last), Cl(ren), maximal urinary concentration (U(max)), AUC(urine0-->last) and UE. Both fluoroquinolones were well tolerated. The plasma concentrations of levofloxacin were significantly higher than those of ciprofloxacin XR throughout the study period. The urinary concentrations of ciprofloxacin XR were significantly higher than those of levofloxacin in the first collection interval (0-4 h), whereas the concentrations of levofloxacin were significantly higher than those of ciprofloxacin XR in the five last collection intervals (12-36 h). The median proportions of cumulative renal excretion of the administered dose of the parent drug up to 36 h were 43.1% for ciprofloxacin XR (range, 13.7-50.8%; mean +/- standard deviation (S.D.), 40.5 +/- 9.9%) and 79.8% for levofloxacin (range, 74.0-88.2%; mean +/- S.D., 80.4 +/- 5.5%). C(max), AUC(plasma0-->infinity), AUC(plasma0-->last) and UE were statistically significantly higher in the levofloxacin than in the ciprofloxacin XR phase; t(max), Cl(ren) and U(max) were statistically significantly higher in the ciprofloxacin XR phase than in the levofloxacin phase; and AUC(urine0-->last) and t(1/2) were not statistically different. After an oral administration of ciprofloxacin XR 1000 mg and levofloxacin 500 mg, C(max) and AUC(plasma0-->infinity) were significantly higher in the levofloxacin phase. UE of ciprofloxacin XR 1000 mg once daily, however, was equivalent to that of levofloxacin 500 mg, and overall comparable urinary concentrations and AUC(urine) were reached by both drugs. Therefore, it can be assumed that the two doses investigated can be considered equivalent for the treatment of UTI.

Current challenges in the treatment of complicated urinary tract infections and prostatitis

Serious urinary tract infections (UTIs) and acute bacterial prostatitis in adults cause significant morbidity and economic burden. Chronic bacterial prostatitis is a rather rare condition seen in urological practice, however, in certain occasions difficult to treat. In this paper, we review the bacterial etiologies and the resistance patterns found in adults with serious UTIs and bacterial prostatitis, and discuss considerations for selecting optimal antimicrobial therapy. The role of fluoroquinolones as targeted therapy for serious UTIs is highlighted. The use of effective antimicrobial therapy is the foundation of management of serious UTIs and bacterial prostatitis. Selection of the optimal antimicrobial agent must take into account patient-specific factors; infection characteristics (e.g., severity, community- vs. institutional- or hospital-acquired, need for IV agent, UTI, prostatitis); local resistance pattern; pharmacokinetic and pharmacodynamic principles; and cost. Fluoroquinolones are among the alternatives for empirical antibiotic treatment of serious UTIs and acute bacterial prostatitis. In serious UTIs activity of the antimicrobial agent against Pseudomonas aeruginosa needs to be taken into account. In chronic bacterial prostatitis fluoroquinolones are the first choice because of their favourable pharmacokinetic properties at the site of infection. Targeted antimicrobial therapy--emphasising the correct antibacterial spectrum and correct dosage--is likely to provide important benefits, such as reduced morbidity and associated costs, reduced emergence of resistance and maintenance of class efficacy.

Emergence of antibiotic resistance amongst hospital-acquired urinary tract infections and pharmacokinetic/pharmacodynamic considerations

Bacterial urinary tract infections (UTIs) are frequent infections in the nosocomial setting. Nosocomial UTIs are almost exclusively complicated UTIs, although the complicating factors may be very heterogenous. The bacterial spectrum of nosocomial UTIs is broad and antibiotic resistance is common. The results of international and national surveillance studies on the bacterial spectrum and antibiotic resistance of nosocomial uropathogens are provided. The treatment of nosocomial UTIs encompasses treatment of the complicating factors as well as antimicrobial chemotherapy. At least in serious UTIs, adequate initial antibiotic therapy results in lower mortality. Therefore, the initial antibiotic regimen must provide sufficient antibiotic cover. However, this can only be achieved if the bacterial spectrum and antibiotic resistance patterns of uropathogens in the institution are followed continuously. Provisional microbiological findings, such as reports on Gram stain or certain biochemical results, can lead to early stratification of pathogens and allow more tailored empiric antibiotic therapy. Antibiotic therapy of nosocomial UTIs has to consider two different aspects: (1) therapeutic success in the individual patient; and (2) prevention of emergence of antibiotic-resistant mutants. The emergence of resistance can possibly be lowered by adequate drug selection and dosing. Increasing antibiotic resistance requires more prudent use of antimicrobial drugs.

Emerging drugs for bacterial urinary tract infections

Bacterial urinary tract infections (UTIs) are frequent infections in the outpatient as well as in the nosocomial setting. The stratification into uncomplicated and complicated UTIs has proven to be clinically useful. Bacterial virulence factors on the one side and the integrity of the host defence mechanisms on the other side determine the course of the infection. In uncomplicated UTIs, Escherichia coli is the leading organism, whereas in complicated UTIs, the bacterial spectrum is much broader, including Gram-negative, Gram-positive and often multiresistant organisms. The therapy of uncomplicated UTIs is almost exclusively antibacterial, whereas in complicated UTIs the complicating factors also have to be treated. There are two predominant aims in the antimicrobial treatment of both uncomplicated and complicated UTIs: i) rapid and effective response to therapy and prevention of recurrence of the individual patient treated; and ii) prevention of emergence of resistance to chemotherapy in the microbial environment. The aim of this review is to highlight the existing, and to describe emerging, treatment options for UTIs.

Prospective, Randomized, Multicentric, Open, Comparative Study on the Efficacy of a Prophylactic Single Dose of 500mg Levofloxacin versus 1920mg Trimethoprim/Sulfamethoxazole versus a Control Group in Patients Undergoing TUR of the Prostate

OBJECTIVES

Transurethral resection of the prostate (TUR-P) is one of the most frequent urological procedures. The efficacy of a prophylactic single dose of levofloxacin vs. trimethoprim/sulfamethoxazole (TMP/SMZ) vs. a control group, receiving no antibiotic prophylaxis, in patients undergoing TUR-P was investigated in a multicentre study. The aims were to assess the rate of bacteriuria (cfu> or =10(4)/ml) 5 to 7 days, and 3 to 5 weeks after TUR-P, as well as postoperative complications.

METHODS

The study was prospective, randomized, multicentric, open and comparative. Patients without bacteriuria (cfu<10(4)/ml) scheduled for TUR-P and not having received antibiotics prior within four days were enclosed. Patients received an oral single dose prophylaxis with either 500 mg levofloxacin, or 320/1600 mg TMP/SMZ, or no prophylaxis according to a 2:2:1 randomization. Clinical examination of the patients and urine culture were performed prior to, 5 to 7 days and 3 to 5 weeks after TUR-P.

RESULTS

14 urological centres throughout Germany recruited 400 patients. 376 patients were evaluable until day 5 to 7, 339 until week 3 to 5. Overall bacteriuria rate at day 5 to 7 was 22% (levofloxacin 21%; TMP/SMZ 20%; control group 30%). Bacteriuria rate at week 3 to 5 was 28% (levofloxacin 26%; TMP/SMZ 26%; control group 36%). Complication rate at week 3 to 5 was 10% (levofloxacin 8%; TMP/SMZ 10%; control group 16%). The rates of postoperative bacteriuria ranged widely between centers (0%-75%). Statistically significant (p<0.05) risk factors for bacteriuria (range) were qualification of surgeon (19%-37%), presence of a suprapubic catheter (22%-34%), disconnection of the closed drainage system (25%-52%), operating time (12%-31%) and operative centre (0%-75%). Total antibiotic consumption (for prophylaxis and treatment) in the control group was higher and more expensive than in groups with antibiotic prophylaxis (6.9 vs. 5.0 doses/patient; 24.9 vs. 19.7 /patient) (p<0.0001). Postoperative complications in patients with bacteriuria (cfu> or =10(4)/ml) were more frequent than in non bacteriuric (cfu<10(4)/ml) patients (17% vs. 8%) (p<0.01).

CONCLUSIONS

It is debatable whether postoperative bacteriuria is the key parameter to define efficacy of antimicrobial prophylaxis in patients undergoing TUR-P. The rate of bacteriuria, however, correlated well with the overall rate of postoperative complications. Therefore, it seems reasonable to lower the rate of bacteriuria by prophylaxis. Since patients without antibiotic prophylaxis received at the end even more antibiotic doses than patients with prophylaxis, the overall selection pressure by antibiotic usage can obviously not be lowered by resigning prophylaxis. Therefore we conclude that at least patients at risk should receive antibiotic prophylaxis prior to TUR-P.

Asymptomatic Bacteriuria in Elderly Patients

Asymptomatic bacteriuria (ASB) is frequent in elderly patients and even more prevalent in residents of long-term care facilities. Furthermore, because more and more people are reaching advanced age and the need for care increases with age, ASB is becoming increasingly important. There are several definitions for ASB, all of which require positive urine cultures and place little or no importance on accompanying pyuria. Most ASB is associated with complicating factors, as might be found in complicated urinary tract infections (UTIs). Thus, the bacterial spectrum associated with ASB is comparable to that seen in complicated UTIs. A variety of complicating factors are more frequently found in elderly patients with ASB, such as hormonal factors (e.g. estrogen decrease), certain anatomical factors (e.g. prostate obstruction), metabolic factors (e.g. diabetes mellitus), functional alteration of the urinary bladder, immunological changes and a high rate of indwelling-catheter use. Screening for ASB in elderly people is limited to those undergoing invasive urological procedures and surgical procedures with implant material. In other situations, examination of the urine is not recommended if signs or symptoms in the urinary tract are absent. Treatment of ASB is recommended only before urological procedures. Pyuria accompanying ASB is not an indication for antimicrobial treatment. If antimicrobial treatment is considered, concomitant factors that occur frequently in elderly people, such as renal insufficiency, must be taken into account. Although ASB is apparently a benign condition, prevention in elderly people is important. The degree of pathogenicity of bacteria causing ASB has not yet been satisfactorily elucidated. Therefore, until the implications of the bacteria involved in ASB are fully understood, implementing the same hygienic precautions as are used in individuals with symptomatic UTIs should at least be undertaken.

The bacterial insertion sequence element IS256 occurs preferentially in nosocomial Staphylococcus epidermidis isolates: association with biofilm formation and resistance to aminoglycosides

Staphylococcus epidermidis is a normal constituent of the healthy human microflora, but it is also the most common cause of nosocomial infections associated with the use of indwelling medical devices. Isolates from device-associated infections are known for their pronounced phenotypic and genetic variability, and in this study we searched for factors that might contribute to this flexibility. We show that mutator phenotypes, which exhibit elevated spontaneous mutation rates, are rare among both pathogenic and commensal S. epidermidis strains. However, the study revealed that, in contrast to those of commensal strains, the genomes of clinical S. epidermidis strains carry multiple copies of the insertion sequence IS256, while other typical staphylococcal insertion sequences, such as IS257 and IS1272, are distributed equally among saprophytic and clinical isolates. Moreover, detection of IS256 was found to be associated with biofilm formation and the presence of the icaADBC operon as well as with gentamicin and oxacillin resistance in the clinical strains. The data suggest that IS256 is a characteristic element in the genome of multiresistant nosocomial S. epidermidis isolates that might be involved in the flexibility and adaptation of the genome in clinical isolates.