Role of fluoroquinolones in the treatment of serious bacterial urinary tract infections

Antibacterial Mechanisms and Clinical Impact of Sitafloxacin

Sitafloxacin is a 4th generation fluoroquinolone antibiotic with broad activity against a wide range of Gram-negative and Gram-positive bacteria. It is approved in Japan and used to treat pneumonia and urinary tract infections (UTIs) as well as other upper and lower respiratory infections, genitourinary infections, oral infections and otitis media. Compared to other fluoroquinolones, sitafloxacin displays a low minimal inhibitory concentration (MIC) for many bacterial species but also activity against anaerobes, intracellular bacteria, and persisters. Furthermore, it has also shown strong activity against biofilms of P. aeruginosa and S. aureus in vitro, which was recently validated in vivo with murine models of S. aureus implant-associated bone infection. Although limited in scale at present, the published literature supports the further evaluation of sitafloxacin in implant-related infections and other biofilm-related infections. The aim of this review is to summarize the chemical-positioning-based mechanisms, activity, resistance profile, and future clinical potential of sitafloxacin.

Codeine dysregulates ribosome biogenesis in Escherichia coli with DNA double-strand breaks to chart path to new classes of antibiotics

Aim

A bacterial genetics-guided approach was utilized for the discovery of new compounds affecting bacterial genome stability.

Materials & methods

Fungal extracts and fractions were tested for genome instability-mediated antibacterial activity. Interaction assays and RT-qPCR were used to identify compounds that boost the activity of sub-minimum inhibitory concentration streptomycin and obtain insights on the molecular mechanisms of the primary hit compound, respectively.

Results

Several extracts and fractions caused bacterial genome instability. Codeine, in synergy with streptomycin, regulates double-strand break (DSB) repair and causes bacterial ribosome dysfunction in the absence of DSBs, and dysregulation of ribosome biogenesis in a DSB-dependent manner.

Conclusion

This study demonstrates a potential viable strategy that we are exploring for the discovery of new chemical entities with activities against Escherichia coli and other bacterial pathogens.

Optimizing antimicrobial therapy in urinary tract infections: A focus on urine culture and sensitivity testing

Objectives: This cross-sectional study was conducted at Jordan university hospital to evaluate the impact of microbial culture data and sensitivity results on optimizing UTI treatment. Methods: All positive urine cultures requested for adult patients (≥18 years) admitted to Jordan University Hospital (JUH) within the period from January 2019-July 2021 were evaluated. The antibiotics prescribed before and after culture data and sensitivity results were compared to evaluate the impact of these diagnostic measures on optimizing UTI treatment. Results: During the study period, 2400 urine cultures revealed positive results. Among those patients, 1,600 (66.7%) were discharged before the availability of culture results and excluded. Of the remaining 800 patients, 701 patients (87.6%) received empiric treatment. After culture and sensitivity results were available, overall, 84 (10.5%) patients had optimization (improvement) in their UTI management after culture results were known, while 6 (0.8%) patients had a worsening in their treatments. Based on the culture results, we found that only 12.4% of patients were appropriately treated before and after the culture results. Moreover, our results revealed that 31.9% were inappropriately treated for their UTIs before and after culture results. Conclusion: This study revealed an alarmingly high rate of inappropriate treatment of UTIs despite the availability of urine culture and sensitivity data, and that culture results were not used to optimize treatment strategies for UTI. This practice can potentially result in poor health-related outcomes and adversely affects efforts to battle AMR. Multifaceted strategies must be implemented to help clinicians follow the best current evidence and current guidelines in their selection of antibiotics for the management of UTIs.

The Appropriateness of Empiric Treatment of Urinary Tract Infections in a Tertiary Teaching Hospital in Joran: A Cross-Sectional Study

This is a cross-sectional study that was conducted at Jordan University Hospital (JUH) to evaluate the appropriateness of Urinary Tract Infection (UTI) empiric treatment based on microbial culture data and susceptibility testing. All urine cultures requested for adult patients (≥18 years) admitted to JUH within the period from January 2019–July 2021 were reviewed and only those cultures with positive episodes of infection were considered. In this study, 6950 urine culture episodes were screened; among them, 34.5% (n = 2400) revealed positive results. Among those patients with positive culture episodes, 1600 patients (66.7%) were discharged before the availability of culture results and were excluded. Of the remaining eligible 800 patients, 701 (87.6%) received empiric treatment. In 26.8% of the eligible cases (n = 214), the prescribed empiric agents failed to have appropriate coverage of the identified pathogens, and in 14.6% of the cases (n = 117) the identified microorganisms were reported as resistant to the prescribed empiric agents. Furthermore, only 13.4% of the patients (n = 107) were appropriately treated for their UTI with empiric antibacterial agents. We were not able to judge the appropriateness of UTI treatment for one third (n = 263, 32.9%) of the patients, because they did not have susceptibility reports performed. This study revealed an alarmingly high rate of inappropriate treatment of UTIs, which encourages the emergence of bacterial resistance and affects health-related outcomes negatively. Therefore, antimicrobial stewardship programs must be applied to optimize antibiotic consumption in hospital settings.

Complicated urinary tract infection in patients with benign prostatic hyperplasia

Complicated urinary tract infection (UTI) is a symptomatic urinary infection accompanied by functional or structural abnormalities of the genitourinary tract. Benign prostatic hyperplasia (BPH) is a major cause of lower urinary tract obstruction in male patients, and bladder outlet obstruction (BOO) secondary to BPH can lead to UTIs in men. However, no evidence has clearly shown that UTI in the aging male population is associated with either post-void residual urine or BOO. Screening for the presence of bacteriuria is recommended prior to any procedure manipulating the urinary tract, and imaging studies of the upper urinary tract are recommended to identify underlying abnormalities. Recurrent or persistent UTI in men with BPH is an indication for surgical treatment. Asymptomatic bacteriuria should be screened for and treated before transurethral resection of the prostate (TURP). In addition, antibiotic prophylaxis reduced the risk of UTI in patients undergoing TURP. The choice of specific antimicrobial for prophylaxis should be based on local pathogen prevalence and individual antibiotic susceptibility. Patients with severe systemic infections require hospitalization, and empirical therapy should include an intravenous antimicrobial regimen. Further prospective studies are needed to refine the treatment process for complicated UTI in patients diagnosed with BPH.

In vitro activity of plazomicin against quinolone-resistant gram-negative bacteria isolated from catheter-associated urinary tract infections

Quinolone resistance among uropathogens is an increasing concern. Plazomicin is a new aminoglycoside that shows promising results against resistant bacteria. However, no study has yet tested its effect specifically on quinolone-resistant organisms. This study aimed to evaluate the in vitro activity of plazomicin and comparator drugs against quinolone-resistant Gram-negative isolates of catheter-associated urinary tract infections (CAUTI). Plazomicin demonstrated high inhibiting activity against Enterobacteriaceae isolates (95.9% at MIC≤ 2 mg/L), with MIC_50/90 was 1/2 mg/L. High MICs values were detected against non-Enterobacteriaceae isolates (MIC_50/90, 4/32 mg/L). Plazomicin had susceptibility rate of 97.2% against Enterobacteriaceae isolates carrying aminoglycosides modifying enzymes (AME) genes, while other aminoglycosides, amikacin and gentamicin showed reduced activity (32.4% and 25.4%, respectively). In conclusion, plazomicin showed potent in vitro activity against quinolone-resistant Enterobacteriaceae causing CAUTI, regardless of the AME pattern.

Prevalence of quinolone-resistant uropathogenic Escherichia coli in a tertiary care hospital in south Iran

Background: Quinolones are a family of synthetic antimicrobial agents with a broad antibacterial activity commonly used as a suitable therapy in patients with urinary tract infection (UTI). In the present study, we aimed to evaluate the prevalence of quinolones resistance and the presence of plasmid-mediated quinolone resistance (PMQR) genes among Escherichia coli isolates.

Methods

This study was performed on a collection of 121 E. coli isolates derived from patients with UTI. Antimicrobial susceptibility to nalidixic acid, ciprofloxacin, levofloxacin, norfloxacin, and ofloxacin was specified by the disk diffusion method. The presence of PMQR genes was determined by PCR method.

Results

Antibiotic susceptibility results showed that the highest and lowest resistance rates were against nalidixic acid (71.9%) and norfloxacin (44.6%), respectively. The molecular results showed that 40 (33.1%) and 15 (12.4%) of the isolates were positive for qnrS and qnrB genes, respectively. Meanwhile, 5 (4.1%) of the isolates were found positive for both genes, while none were found to be positive for qnrA gene. There was no significant association between the presence of qnr genes and higher antibiotic resistance.

Conclusion

We found high levels of quinolones resistance (more than 40%) among E. coli strains isolated from patients with UTIs in the south of Iran. We further report the prevalence of PMQR genes among uropathogenic E. coli; however, it seems that these genes are not the main components of quinolone resistance in our region.

The use of SWATH to analyse the dynamic changes of bacterial proteome of carbapanemase-producing Escherichia coli under antibiotic pressure

Antibiotic resistance associated with the clinically significant carbapenemases KPC, NDM and OXA-48 in Enterobacteriaceae is emerging as worldwide. In Australia, IMP-producing Enterobacteriaceae are the most prevalent carbapenemase-producing Enterobacteriaceae (CPE). Genomic characteristics of such CPE are well described, but the corresponding proteome is poorly characterised. We have thus developed a method to analyse dynamic changes in the proteome of CPE under antibiotic pressure. Specifically, we have investigated the effect of meropenem at sub-lethal concentrations to develop a better understanding of how antibiotic pressure leads to resistance. Escherichia coli strains producing either NDM-, IMP- or KPC-type carbapenemases were included in this study, and their proteomes were analysed in growth conditions with or without meropenem. The most significant difference in the bacterial proteomes upon the addition of meropenem was triggered amongst NDM-producers and to a lower extent amongst KPC-producers. In particular, HU DNA-binding proteins, the GroEL/GroES chaperonin complex and GrpE proteins were overexpressed. These proteins may thus contribute to the better adaptability of NDM- and KPC-producers to meropenem. A significant meropenem-induced increase in the expression of the outer membrane protein A was only observed in IMP-producers, thus demonstrating that carbapenemase-mediated resistance relies on far more complex mechanisms than simple inactivation of the antibiotic.

Ciprofloxacin resistance in uropathogenic Escherichia coli isolates causing community-acquired urinary infections in Brasília, Brazil

OBJECTIVES

Considering the global concern of ciprofloxacin resistance, the aim of this study was to evaluate the characteristics of ciprofloxacin-resistant (CIP-R) Escherichia coli isolated from patients with community-acquired urinary tract infections (UTIs) in Brasília, Brazil.

METHODS

CIP-R E. coli isolated from different outpatients between July 2013 and April 2014 in a tertiary hospital were analysed for antibiotic resistance profile, phylotype, uropathogenic E. coli (UPEC) virulence genes, clonal relationship by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR), and multilocus sequence typing (MLST).

RESULTS

Among the 324 UPEC analysed, 263 (81.2%) were ciprofloxacin-sensitive and 61 (18.8%) were CIP-R. Antibiogram analysis of the 61 CIP-R strains showed that 45 (73.8%) were also multidrug-resistant. The most prevalent phylogroups were A and B2 (26/61 and 18/61, respectively). traT (53/61) and aer-traT (24/61) were the most common gene and genotype observed. Dendrogram analysis found that multidrug resistance and virulence genes were distributed among CIP-R strains independently of clonality and phylogroup. Six ERIC clusters (strains sharing ≥85% genetic similarity) were observed. MLST analysis of all strains of each cluster identified sequence types (STs) associated with worldwide antimicrobial resistance dissemination, including B2-ST131 and ST410, as well as STs not yet associated with antimicrobial resistance propagation, such as ST1725 and ST179.

CONCLUSIONS

These results demonstrate that ciprofloxacin resistance dissemination by UPEC causing community-acquired UTIs was associated with multidrug resistance and was promoted by pandemic and non-pandemic STs, a concerning scenario for the local population.

Role of age and sex in determining antibiotic resistance in febrile urinary tract infections

OBJECTIVES

To identify the age- and sex-specific antimicrobial susceptibility patterns of Gram-negative bacteria (GNB) in outpatient febrile urinary tract infections (UTIs) in Korea.

METHODS

A total 2262 consecutive samples collected from patients aged 1-101 years with febrile UTIs, during the period January 2012 to December 2014, were analyzed in this multicentre, retrospective cohort study.

RESULTS

The sensitivities to cefotaxime and cefoxitin were over 85% for females but under 75% for males. Sex played an important role in the susceptibility of GNB to cefotaxime (p<0.001) and cefoxitin (p<0.001). The sensitivity to ciprofloxacin (age >20 years) was under 75% in both sexes, and was not influenced by sex (p=0.204). Age distributions of the incidences of resistance to cefotaxime, cefoxitin, and ciprofloxacin (age >20 years) were similar to the age distribution of the incidence of GNB, which indicates that the resistance patterns to these drugs were not affected by age (Kolmogorov-Smirnov test, female/male: p=0.927/p=0.509, p=0.193/p=0.911, and p=0.077/p=0.999, respectively).

CONCLUSIONS

Age is not a considerable factor in determining the antibiotic resistance in febrile UTIs. Ciprofloxacin should be withheld from both sexes until culture results indicate its use. Second- or third-generation cephalosporins such as cefoxitin and cefotaxime can be used empirically only in females.

Susceptibility pattern of uropathogens to ciprofloxacin at the Ghana police hospital

INTRODUCTION

Reports of increasing resistance of uropathogens to antimicrobials is of global concern. Culture and drug susceptibility tests remain a vital guide to effective therapy. The aim of this study was to determine the susceptibility pattern of isolated uropathogens to ciprofloxacin at the Ghana Police Hospital.

METHODS

A total of 705 mid-stream urine samples were collected from patients suspected of having urinary tract infection, and visited the Ghana Police Hospital's laboratory from December 2013 to March 2014. Samples were cultured and isolates identified by standard methods, after which isolates susceptibility to ciprofloxacin was determined.

RESULTS

Prevalence of urinary tract infection among patients' whose samples were analyzed was 15.9%. Predominant uropathogens isolated were E. coli (46.4%), Coliform (41.1%) and Coliform spp. with Candida (6.2%). Other isolates were Pseudomonas spp. (2.7%), Salmonella spp. (1.8%), Candida spp. (0.9%) and Klebsiella spp (0.9%). The overall resistance among the top three isolated uropathogens to ciprofloxacin was 35.9%. Resistance pattern demonstrated by respective isolates to ciprofloxacin were: E. coli (38.5%), Coliform (54.3%), and Coliform spp. with Candida (15%). The other isolates showed 100% sensitivity.

CONCLUSION

This study revealed a relatively high ciprofloxacin resistance among isolated uropathogens, hence, the need for prudent prescribing and use of ciprofloxacin in urinary tract infection management.

Antibacterial susceptibility of Escherichia coli among outpatients with community-acquired urinary tract infection in Hamadan, Iran

Escherichia coli is the main cause of community-acquired urinary tract infections (UTIs). The aims of the present study were to examine the susceptibility profile of E. coli causing UTIs and to identify factors associated with antimicrobial resistance. A cross-sectional study was conducted in Hamadan City, Iran, between 2012 and 2013. Patients referred to Farshchian or Shahid Beheshti Hospitals and diagnosed with UTI caused by E. coli were enrolled in the study. Susceptibility testing to commonly used antimicrobial agents was performed by the disk diffusion method. Relevant data were abstracted, and analysis was performed to identify factors associated with antimicrobial resistance. A total of 154 patients were enrolled in the study. Among the respective number of E. coli isolates, the highest susceptibility was observed to nitrofurantoin (94.1%) and gentamicin (86.4%) and the lowest to amoxicillin/clavulanic acid (35.1%), trimethoprim/sulfamethoxazole (38.3%) and ciprofloxacin (51.9%). Twenty-four isolates (15.6%) were susceptible to all antimicrobial tested, 31 (20.1%) were resistant to one agent and 99 (64.3%) exhibited resistance to at least two different classes of antibiotics [multidrug-resistant (MDR) phenotype]. Patients with prior use of antibiotics during the past 3 months and those who had an episode of UTI in the past 2 years were at higher risk of being infected with MDR E. coli (P=0.034 and P=0.001, respectively). In conclusion, a substantial proportion of E. coli causing UTI exhibited a MDR phenotype. History of UTI and prior use of antibiotics were associated with increased risk of infection caused by MDR E. coli.

Percutaneous nephrolithotomy for infection stones: what is the risk for postoperative sepsis? A retrospective cohort study

The purpose of this study was to compare the postoperative course of patients with positive stone culture (SC) to patients with sterile SC, and to analyze the predictors for post percutaneous nephrolithotomy (PCNL) sepsis; and to describe the type and resistance patterns of bacteria responsible for post PCNL sepsis. From a cohort of 206 consecutive patients undergoing PCNL, we identified 45 patients with a positive SC (group A) and compared them to patients with a sterile SC (group B). Association between different groups was assessed using Chi square, two-tailed Student's t test and Mann-Whitney U test, as appropriate. Twenty-three patients had postoperative sepsis and regression analysis was performed to identify clinical variables associated with sepsis. Demographics, stone load and hospitalization time were similar in both groups. Postoperative sepsis developed in 31.1% of patients in group A compared to 5.9% in group B. In multivariate analysis, only positive SC was an independent risk factor for postoperative sepsis (OR 6.894, 95% CI 2.31-20.59, P = 0.001). All patients responded well to treatment with no septic complications. Enterococci were the prevalent organism (29.4%) in patients with a positive SC. Quinolone resistance was high in both gram negative and gram positive bacteria. Patients with an infected stone are at high risk to develop postoperative sepsis despite standard preoperative antibiotic preparation. SC is important to direct further treatment as almost half of patients with positive SC have a discordant or sterile urine culture. Determining the prevalent bacteria and resistance patterns in SC can aid the selection of empiric antibiotic therapy in high-risk patients.

Antibiotic resistance in isolates recovered from women with community-acquired urinary tract infections presenting to a tertiary care emergency department

INTRODUCTION

We sought to determine the antibiotic susceptibility of organisms causing community-acquired urinary tract infections (UTIs) in adult females attending an urban emergency department (ED) and to identify risk factors for antibiotic resistance.

METHODS

We reviewed the ED charts of all nonpregnant, nonlactating adult females with positive urine cultures for 2008 and recorded demographics, diagnosis, complicating factors, organism susceptibility, and risk factors for antibiotic resistance. Odds ratios (ORs) and 95% confidence intervals (CIs) for potential risk factors were calculated.

RESULTS

Our final sample comprised 327 UTIs: 218 were cystitis, of which 22 were complicated cases and 109 were pyelonephritis, including 22 complicated cases. Escherichia coli accounted for 82.3% of all UTIs, whereas Staphylococcus saprophyticus accounted for 5.2%. In uncomplicated cystitis, 9.5% of all isolates were resistant to ciprofloxacin and 24.0% to trimethoprim-sulfamethoxazole (TMP-SMX). In uncomplicated pyelonephritis, 19.5% of isolates were resistant to ciprofloxacin and 36.8% to TMP-SMX. In UTI (all types combined), any antibiotic use within the previous 3 months was a significant risk factor for resistance to both ciprofloxacin (OR 3.34, 95% CI 1.16-9.62) and TMP-SMX (OR 4.02, 95% CI 1.48-10.92). Being 65 years of age or older and having had a history of UTI in the previous year were risk factors only for ciprofloxacin resistance.

CONCLUSIONS

E. coli was the predominant urinary pathogen in this series. Resistance to ciprofloxacin and TMP-SMX was high, highlighting the importance of relevant, local antibiograms. Any recent antibiotic use was a risk factor for both ciprofloxacin and TMP-SMX resistance in UTI. Our findings should be confirmed with a larger prospective study.

Prospective comparative study of two protocols of antibiotic prophylaxis in percutaneous nephrolithotomy

BACKGROUND AND PURPOSE

Percutaneous nephrolithotomy (PCNL) is considered to be a clean-contaminated surgical procedure, and all patients are recommended to receive antibiotic prophylaxis before the operation to prevent septic events. The aim of the present study is to prospectively compare two different protocols of antibiotic prophylaxis in PCNL.

PATIENTS AND METHODS

Seventy-three patients with preoperative sterile urine were randomized into single-dose or short-course antibiotic prophylaxis groups. Patients in the first group (n=36) were given only a single dose of ceftriaxone during induction of anesthesia, while the second group (n=37) were given an oral third-generation cephalosporin after ceftriaxone until nephrostomy catheter withdrawal. For each patient, urine samples that were taken during initial access into the collecting system, as well as some stone fragments, were sent for culture and sensitivity analysis. Moreover, urine samples of the patients were cultured preceding nephrostomy catheter removal. Occurrence of perioperative infection related events was compared in both groups.

RESULTS

The demographic and treatment-related characteristics of both groups were similar. Peroperative urine samples revealed bacteriuria in one and two patients for the first and second groups, respectively. Fever of >38°C (P=0.52) developed in four (11.1%) patients in the first and six (16.2%) patients in the second group. Positive stone cultures developed in eight patients; of those, three (8.3%) were in the first and five (13.5%) were in the second group (P=0.47). The urine sent for culture on the nephrostomy catheter withdrawal day had positive results in three and two patients for the first and second groups (P=0.54).

CONCLUSION

Both antibiotic prophylaxis methods were similar in terms of preventing septic complications. Therefore, we think that a single-dose antibiotic prophylaxis protocol may be safely recommended to patients undergoing PCNL.

The changing pattern of antimicrobial resistance within 42,033 Escherichia coli isolates from nosocomial, community and urology patient-specific urinary tract infections, Dublin, 1999-2009

OBJECTIVE

To investigate the changing pattern of antimicrobial resistance in Escherichia coli urinary tract infection over an eleven year period, and to determine whether E. coli antibiotic resistance rates vary depending on whether the UTI represents a nosocomial, community acquired or urology patient specific infection.

PATIENT AND METHODS

A retrospective analysis of the 42,033 E. coli urine isolates from the 11-year period 1999-2009 in a single Dublin teaching hospital was performed. WHONET(TM) software was used to analyse the changing pattern of sensitivity and resistance of E. coli to commonly used antibiotics over the study period. The origins of the urine samples were stratified into three groups: inpatients with nosocomial UTIs; urine originating from the emergency department and general practice (community UTIs); and UTIs in urology patients.

RESULTS

Urinary tract infections in the urology patient population demonstrate higher antibiotic resistance rates than nosocomial or community UTIs. There were significant trends of increasing resistance over the 11-year period for ampicillin, trimethoprim, gentamicin and ciprofloxacin, and significant differences in co-amoxyclav, gentamicin, nitrofurantion and ciprofloxacin resistance rates depending on the sample origin. Ampicillin and trimethoprim were the least active agents against E. coli, with total 11-year resistance rates of 58.3 and 33.8%, respectively. The overall gentamicin resistance rate was 3.4% and is climbing at a rate of 0.7% per year (P < 0.001). Within the urology patient population the resistance rate was 6.4%. Ciprofloxacin resistance approaches 20% in the nosocomial UTI population and approaches 30% in the urology population; however, it remains a reasonable empirical antibiotic choice in this community, with an 11-year resistance rate of 10.6%.

CONCLUSIONS

E. coli remains the commonest infecting uropathogen in the community and hospital setting with its incidence climbing from 50 to 60% of UTIs over the 11-year period. Neither penicillins nor trimethoprim represent suitable empirical antimicrobials for UTI and ciprofloxacin resistance in this Dublin-based study renders it unsuitable empirical therapy for nosocomial UTIs and UTIs in the urology population. The dramatic 11-year rate increase in gentamicin resistance is of paramount concern.

Enterobactérias produtoras de ESBL em Passo Fundo, estado do Rio Grande do Sul, Brasil

INTRODUÇÃO: O principal mecanismo de resistência emergente entre Enterobacteriaceae é a produção de β-lactamases de espectro estendido, enzimas capazes de hidrolisar cefalosporinas-de-amplo-espectro, que são bastante utilizadas na terapia antimicrobiana de infecções por enterobactérias. Embora a resistência a esses agentes apresente grande variabilidade geográfica, os índices de resistência são elevados em diversos países MÉTODOS: Um estudo observacional, transversal, descritivo e retrospectivo foi desenvolvido para avaliar a frequência de ESBL entre cepas de Enterobacteriaceae obtidas no Hospital São Vicente de Paulo, Brasil RESULTADOS: A produção de ESBL foi observada em 24,8% (nº=208/838) dos isolados avaliados. Isolados de Escherichia coli representaram 46,2% (nº=96/208) do percentual de produtores de ESBL, seguido de espécies de Enterobacter 30,3% (nº=63/208). A sensibilidade desses isolados ao meropenem foi de 91,4% e a piperacilina/tazobactam de 67,4% CONCLUSÕES: Os índices de ESBL encontrados confirmam a preocupação mundial com este mecanismo de resistência.

Efficacy and safety of ciprofloxacin XR 1000 mg once daily versus ciprofloxacin 500 mg twice daily in the treatment of complicated urinary tract infections

The aim of this trial was to compare the efficacy and safety of extended-release ciprofloxacin (CIPRO XR) versus the immediate-release formulation (CIPRO IR) in the treatment of complicated urinary tract infections (UTIs). 212 patients were randomized to CIPRO XR 1,000 mg tablet once daily or CIPROXIN IR 500 mg tablet twice daily. Treatment efficacy was evaluated by bacteriological outcome. Safety was measured by recording adverse events. The rate of bacteriological eradication was 83% in the CIPRO XR group and 75% in the CIPRO IR. the overall incidence of adverse events reported was higher in the CIPRO IR group. The authors conclude that CIPRO XR is a safe and effective treatment for complicated UTIs. Although the limited data available do not consent to support a statistically superior efficacy or safety compared to CIPRO IR, a trend in favor of CIPRO XR is clearly evident in all efficacy and safety variables. CIPRO XR is associated with reduced frequencies of drug-related adverse events compared to CIPRO IR.

Eradication of Pathogenic Bacteria by Remote Delivery of Nitric Oxide via Light-Triggering of Nitrosyl-Containing Materials

Although nitric oxide (NO) delivery systems have been fabricated with sol-gel-based materials, remote control of such systems with light has not been achieved. In this work, a fiber optic-based NO delivery system is described in which the photoactive metal-nitrosyl, [Mn(PaPy(3))(NO)]ClO(4) (1), has been employed in a sol-gel material. The material (1*FO) contains the manganese-nitrosyl which releases NO upon illumination with visible light. The NO-releasing capacity of 1*FO has been measured with an NO-sensitive electrode and the spatial diffusion of NO in solution has been visualized using the Griess reaction. The utility of 1*FO has been demonstrated in effective reduction of bacterial loads of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA). The results suggest that a device that releases NO via illumination by optical fiber may have clinical applications in combating infections with both Gram-positive, Gram-negative and to some degree antibiotic resistant bacteria.

Levofloxacin : a review of its use as a high-dose, short-course treatment for bacterial infection

Levofloxacin (Levaquin) is a fluoroquinolone antibacterial that is the L-isomer of ofloxacin. A high-dose (750 mg) short-course (5 days) of once-daily levofloxacin is approved for use in the US in the treatment of community-acquired pneumonia (CAP), acute bacterial sinusitis (ABS), complicated urinary tract infections (UTI) and acute pyelonephritis (AP). The broad spectrum antibacterial profile of levofloxacin means that monotherapy is often a possibility in patients with CAP at times when other agents may require combination therapy, although levofloxacin can be used in combination therapy when necessary. The high-dose, short-course levofloxacin regimen maximizes its concentration-dependent bactericidal activity and may reduce the potential for resistance to emerge. In addition, this regimen lends itself to better compliance because of the shorter duration of treatment and the convenient once-daily administration schedule. Oral levofloxacin is rapidly absorbed and is bioequivalent to the intravenous formulation; importantly, patients can transition between the formulations, which results in more options in regards to the treatment regimen and the potential for patients with varying degrees of illness to be treated. Levofloxacin has good tissue penetration and an adequate concentration can be maintained in the urinary tract to treat uropathogens. Levofloxacin is generally well tolerated and has good efficacy in the treatment of patients with CAP, ABS, complicated UTI and AP. The efficacy and tolerability of levofloxacin 500 mg once daily for 10 days in patients with CAP, ABS and UTIs is well established, and the high-dose, short-course levofloxacin regimen has been shown to be noninferior to the 10-day regimen in CAP and ABS, and to have a similar tolerability profile. Similarly, the high-dose, short-course levofloxacin regimen is noninferior to ciprofloxacin in patients with complicated UTI or AP. Thus, levofloxacin is a valuable antimicrobial agent that has activity against a wide range of bacterial pathogens; however, its use should be considered carefully so that the potential for resistance selection can be minimized and its usefulness in severe infections and against a range of penicillin- and macrolide-resistant pathogens can be maintained.

Comparative bioavailability of norfloxacin tablets based on blood and urine data

OBJECTIVE

To assess the bioavailability of norfloxacin from urinary excretion relative to plasma concentration.

MATERIALS AND METHODS

Twelve healthy volunteers (22-33 years) participated in the study. Each received a previously developed (M), a local (L) and a multinational (Noroxin) tablet (Ref), 400 mg each, according to a random balanced three-way crossover design on 3 different days. Blood samples were collected over a 12-hour period and urine over a 24-hour period. Norfloxacin concentrations were analyzed by a validated HPLC method.

RESULTS

An initial estimate of bioequivalence of the three products was obtained using analysis of variance on transformed data and based on confidence interval calculation. Elimination pharmacokinetic parameters (half-life and renal clearance) calculated from plasma concentration and urinary excretion data (mean values, n = 36) were comparable to reported values for norfloxacin. Interproduct differences in elimination parameters (mean values, n = 12) were statistically insignificant (F values, ANOVA). Strong association was found between the mean of plasma concentration and urinary excretion rates for many volunteers (F values, regression analysis). Relative bioavailability values calculated for the local and previously developed products relative to Noroxin were higher than 85% based on area under the curve and urinary excretion. Bioequivalence could not be established among the three tested products based on calculated 90% confidence intervals.

CONCLUSION

Urinary excretion of norfloxacin may be a useful noninvasive tool for bioavailability assessment of norfloxacin oral formulations.

Resistance in gram-negative bacteria: Enterobacteriaceae

The emergence and spread of resistance in Enterobacteriaceae are complicating the treatment of serious nosocomial infections and threatening to create species resistant to all currently available agents. Approximately 20% of Klebsiella pneumoniae infections and 31% of Enterobacter spp infections in intensive care units in the United States now involve strains not susceptible to third-generation cephalosporins. Such resistance in K pneumoniae to third-generation cephalosporins is typically caused by the acquisition of plasmids containing genes that encode for extended-spectrum beta-lactamases (ESBLs), and these plasmids often carry other resistance genes as well. ESBL-producing K pneumoniae and Escherichia coli are now relatively common in healthcare settings and often exhibit multidrug resistance. ESBL-producing Enterobacteriaceae have now emerged in the community as well. Salmonella and other Enterobacteriaceae that cause gastroenteritis may also be ESBL producers, which is of relevance when children require treatment for invasive infections. Resistance of Enterobacter spp to third-generation cephalosporins is most typically caused by overproduction of AmpC beta-lactamases, and treatment with third-generation cephalosporins may select for AmpC-overproducing mutants. Some Enterobacter cloacae strains are now ESBL and AmpC producers, conferring resistance to both third- and fourth-generation cephalosporins. Quinolone resistance in Enterobacteriaceae is usually the result of chromosomal mutations leading to alterations in target enzymes or drug accumulation. More recently, however, plasmid-mediated quinolone resistance has been reported in K pneumoniae and E coli, associated with acquisition of the qnr gene. The vast majority of Enterobacteriaceae, including ESBL producers, remain susceptible to carbapenems, and these agents are considered preferred empiric therapy for serious Enterobacteriaceae infections. Carbapenem resistance, although rare, appears to be increasing. Particularly troublesome is the emergence of KPC-type carbapenemases in New York City. Better antibiotic stewardship and infection control are needed to prevent further spread of ESBLs and other forms of resistance in Enterobacteriaceae throughout the world.

Resistance in gram-negative bacteria: enterobacteriaceae

The emergence and spread of resistance in Enterobacteriaceae are complicating the treatment of serious nosocomial infections and threatening to create species resistant to all currently available agents. Approximately 20% of Klebsiella pneumoniae infections and 31% of Enterobacter spp infections in intensive care units in the United States now involve strains not susceptible to third-generation cephalosporins. Such resistance in K pneumoniae to third-generation cephalosporins is typically caused by the acquisition of plasmids containing genes that encode for extended-spectrum beta-lactamases (ESBLs), and these plasmids often carry other resistance genes as well. ESBL-producing K pneumoniae and Escherichia coli are now relatively common in healthcare settings and often exhibit multidrug resistance. ESBL-producing Enterobacteriaceae have now emerged in the community as well. Salmonella and other Enterobacteriaceae that cause gastroenteritis may also be ESBL producers, which is of relevance when children require treatment for invasive infections. Resistance of Enterobacter spp to third-generation cephalosporins is most typically caused by overproduction of AmpC beta-lactamases, and treatment with third-generation cephalosporins may select for AmpC-overproducing mutants. Some Enterobacter cloacae strains are now ESBL and AmpC producers, conferring resistance to both third- and fourth-generation cephalosporins. Quinolone resistance in Enterobacteriaceae is usually the result of chromosomal mutations leading to alterations in target enzymes or drug accumulation. More recently, however, plasmid-mediated quinolone resistance has been reported in K pneumoniae and E coli, associated with acquisition of the qnr gene. The vast majority of Enterobacteriaceae, including ESBL producers, remain susceptible to carbapenems, and these agents are considered preferred empiric therapy for serious Enterobacteriaceae infections. Carbapenem resistance, although rare, appears to be increasing. Particularly troublesome is the emergence of KPC-type carbapenemases in New York City. Better antibiotic stewardship and infection control are needed to prevent further spread of ESBLs and other forms of resistance in Enterobacteriaceae throughout the world.

Ertapenem: a review of its use in the treatment of bacterial infections

The Group 1, 1 beta-methyl carbapenem ertapenem (Invanz) is approved for parenteral use in patients with complicated intra-abdominal infection (cIAI), community-acquired pneumonia (CAP) and acute pelvic infection caused by susceptible strains of certain designated organisms in both the US and the EU. Additional approved indications in the US include complicated skin and skin structure infection (cSSSI) and complicated urinary tract infection (cUTI). Ertapenem is approved for use in adults in both the US and the EU and in paediatric patients aged >or=3 months in the US. Ertapenem has a broad spectrum of in vitro activity against Gram-negative pathogens, including extended-spectrum beta-lactamase (ESBL)- and AmpC-producing Enterobacteriaceae, Gram-positive pathogens and anaerobic pathogens. It has similar efficacy to comparator antibacterials such as piperacillin/tazobactam in cSSSI (including diabetic foot infection), cIAI and acute pelvic infection and ceftriaxone with or without metronidazole in cIAI, cUTI and CAP. The drug has also shown efficacy in the treatment of paediatric patients with complicated community-acquired bacterial infections. Ertapenem has a convenient once-daily administration schedule and is generally well tolerated. Thus, ertapenem is an important option for the empirical treatment of complicated community-acquired bacterial infections in hospitalised patients.

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.

Prulifloxacin versus ciprofloxacin in the treatment of adults with complicated urinary tract infections

INTRODUCTION

The present study was performed to evaluate the efficacy and safety of a 10-day regimen of prulifloxacin 600 mg once daily as compared to ciprofloxacin 500 mg twice daily in the treatment of patients with complicated urinary tract infections (UTIs).

MATERIALS AND METHODS

257 patients (mean age +/- SD 62.3 +/- 16.5) were enrolled and orally treated with prulifloxacin (127 patients) or ciprofloxacin (130 patients). The study was designed as a randomized, double-blind, double-dummy, controlled clinical trial. The primary efficacy parameter was the eradication of infecting strains (<10(3) cfu/ml). The clinical outcome and tolerability were also assessed.

RESULTS

At baseline, the most common infecting strains were Escherichia coli (62.8%), Proteus mirabilis (7.1%) and Klebsiella pneumoniae (4.1%). At the early follow-up, the rate of patients showing successful treatment was 90.8% in the prulifloxacin group, and 77.8% in the ciprofloxacin group (p = 0.008). A positive clinical outcome was observed in 94.8 and 93.3% of prulifloxacin- and ciprofloxacin-treated patients. Both drugs were well tolerated. Two patients dropped out for treatment-related adverse events.

CONCLUSIONS

The high urinary concentrations of prulifloxacin, combined with a broad-spectrum antimicrobial activity, allow its use in the empiric therapy of UTIs.

Endoscopic stone surgery: minimizing the risk of post-operative sepsis

PURPOSE OF REVIEW

Urosepsis from manipulation of the urinary tract during stone surgery can be catastrophic despite antibiotic prophylaxis and sterile pre-operative urine. We have reviewed recent literature with regards to pathogenesis, predictors of infected stones and prevention of urosepsis.

RECENT FINDINGS

Bladder urine culture has been found to correlate poorly with infection in the upper urinary tract, defined by either stone or pelvic urine culture. This specimen, which has been the cornerstone in pre-operative preparation of patients, does not predict urosepsis. Authors recommending routine stone culture found that the presence of infected stones is highly predictive of potential sepsis. Terminology for systemic infection has been standardized and used in recent literature to define urosepsis.

SUMMARY

Recent studies have recommended changes in the approach to the peri-operative management of stone surgery. Predictors of potential sepsis have also been identified.

Appropriate antibiotic treatment of genitourinary infections in hospitalized patients

The etiology of urinary tract infections (UTIs) that require hospitalization, whether they originate in the hospital or in the community, is changing, with increasing findings of gram-positive organisms. The Council for Appropriate and Rational Antibiotic Therapy (CARAT) criteria recommend evaluating treatment choices on the basis of sound clinical evidence, potential for therapeutic benefits, safety, optimal duration of treatment, and cost-efficacy in order to improve antibiotic treatment. Evidence-based guidelines recommend fluoroquinolones for the treatment of patients with cases of pyelonephritis or bacterial prostatitis severe enough to warrant hospitalization. For other serious UTIs, fluoroquinolones are usually recommended either when traditional agents have failed or when resistance to traditional agents is high. Even in the context of rapidly changing antimicrobial resistance patterns, the fluoroquinolones have maintained consistent, well-tolerated efficacy against many of the principal organisms responsible for UTIs, and are generally considered safe for most patients. To increase the likelihood of treatment success with first-line therapy, an antimicrobial agent must attain sufficient concentrations in the target tissue or in the urine for an appropriate amount of time. Both levofloxacin and gatifloxacin are excreted unchanged in the urine in concentrations that far exceed the minimum inhibitory concentration of most uropathogens. Factors that affect cost-effectiveness that should be considered include acquisition costs as well as treatment success and ease of use for hospital staff.