The ARESC study: an international survey on the antimicrobial resistance of pathogens involved in uncomplicated urinary tract infections

Pathogenesis of human diffusely adhering Escherichia coli expressing Afa/Dr adhesins (Afa/Dr DAEC): current insights and future challenges

The pathogenicity and clinical pertinence of diffusely adhering Escherichia coli expressing the Afa/Dr adhesins (Afa/Dr DAEC) in urinary tract infections (UTIs) and pregnancy complications are well established. In contrast, the implication of intestinal Afa/Dr DAEC in diarrhea is still under debate. These strains are age dependently involved in diarrhea in children, are apparently not involved in diarrhea in adults, and can also be asymptomatic intestinal microbiota strains in children and adult. This comprehensive review analyzes the epidemiology and diagnosis and highlights recent progress which has improved the understanding of Afa/Dr DAEC pathogenesis. Here, I summarize the roles of Afa/Dr DAEC virulence factors, including Afa/Dr adhesins, flagella, Sat toxin, and pks island products, in the development of specific mechanisms of pathogenicity. In intestinal epithelial polarized cells, the Afa/Dr adhesins trigger cell membrane receptor clustering and activation of the linked cell signaling pathways, promote structural and functional cell lesions and injuries in intestinal barrier, induce proinflammatory responses, create angiogenesis, instigate epithelial-mesenchymal transition-like events, and lead to pks-dependent DNA damage. UTI-associated Afa/Dr DAEC strains, following adhesin-membrane receptor cell interactions and activation of associated lipid raft-dependent cell signaling pathways, internalize in a microtubule-dependent manner within urinary tract epithelial cells, develop a particular intracellular lifestyle, and trigger a toxin-dependent cell detachment. In response to Afa/Dr DAEC infection, the host epithelial cells generate antibacterial defense responses. Finally, I discuss a hypothetical role of intestinal Afa/Dr DAEC strains that can act as "silent pathogens" with the capacity to emerge as "pathobionts" for the development of inflammatory bowel disease and intestinal carcinogenesis.

Epidemiology and characteristics of urinary tract infections in children and adolescents

Background: Urinary tract infections (UTIs) are among the most common infections in the pediatric population. Over the last two decades, antibiotic resistance is increasing significantly as extended spectrum beta lactamase (ESBL) producing organisms are emerging. The aim of this study is to provide a comprehensive view of the epidemiologic characteristics of UTIs in hospitalized children, examine the risk factors of UTIs caused by ESBL-producing organisms, and determine the resistance patterns in the isolated organisms over the last 10 years.

Methods: Retrospective chart review was conducted at two Lebanese medical centers. Subjects were identified by looking at the following ICD-9 discharge codes: “Urinary tract infection,” “UTI,” “Cystitis,” and/or “Pyelonephritis.” Children less than 18 years of age admitted for UTI between January 1st, 2001 and December 31st, 2011 were included. Cases whose urine culture result did not meet our definition for UTI were excluded. Chi-square, Fisher's exact test, and multivariate logistic regression were used to determine risk factors for ESBL. Linear regression analysis was used to determine resistance patterns.

Results: The study included 675 cases with a median age of 16 months and female predominance of 77.7% (525 cases). Of the 584 cases caused by Escherichia coli or Klebsiella spp, 91 cases (15.5%) were found to be ESBL-producing organisms. Vesico-ureteral reflux and previous antibiotics use were found to be independent risk factors for ESBL-producing E. coli and Klebsiella spp. (p < 0.05). A significant linear increase in resistance to all generations of Cephalosporins (r² = 0.442) and Fluoroquinolones (r² = 0.698) was found.

Conclusion: The recognition of risk factors for infection with ESBL-producing organisms and the observation of increasing overall resistance to antibiotics warrant further studies that might probably lead to new recommendations to guide management of UTIs and antibiotic use in children and adolescents.

Pharmacological aspects of the antibiotics used for urological diagnostic procedures

Surgical antimicrobial prophylaxis is the use of an antibiotic before, during, or shortly after a urological procedure to prevent postoperative infections such as urinary tract or wound infection. The optimal antimicrobial drug must be microbiologically active against the most frequent potential pathogens and have good pharmacological properties. Correct timing of antimicrobial prophylaxis is the first critical issue in determining treatment efficacy. The antibiotic must be administered before the start of the surgical procedure in order to ensure a high tissue level at the time of microbial contamination. If using an oral antibiotic, this must be administered 1-3 hours before the operation and a parenteral antibiotic should be administered at the induction of anaesthesia. The antibiotics potentially useful for antimicrobial prophylaxis are the beta-lactams, cotrimoxazole, fluoroquinolones, and fosfomycin trometamol. The criteria for choosing the optimal antibiotic include an appropriate antimicrobial spectrum, favourable pharmacokinetic parameters (especially good tissue penetration), and elevated safety or tolerability. The use of cotrimoxazole must be restricted due to increasing chemoresistance. Unfortunately fluoroquinolone-based regimens, once the mainstay of prophylaxis guidelines, are increasingly ineffective due to a constant increase in multidrug-resistant (MDR) Gram-negative bacteria. The same concerns apply with regard to the second and third generation cephalosporins that have problems of resistance and, if administered orally, do not sufficiently penetrate prostatic tissue. An appropriate beta-lactam could be an aminopenicillin combined with a beta-lactamase inhibitor. Fosfomycin trometamol can also be a good potential choice due to its elevated activity against MDR Gram-negative bacteria and its favourable pharmacokinetic parameters, including an elevated penetration into prostatic tissue.

The tyrosine gate of the bacterial lectin FimH: a conformational analysis by NMR spectroscopy and X-ray crystallography

Urinary tract infections caused by uropathogenic E. coli are among the most prevalent infectious diseases. The mannose-specific lectin FimH mediates the adhesion of the bacteria to the urothelium, thus enabling host cell invasion and recurrent infections. An attractive alternative to antibiotic treatment is the development of FimH antagonists that mimic the physiological ligand. A large variety of candidate drugs have been developed and characterized by means of in vitro studies and animal models. Here we present the X-ray co-crystal structures of FimH with members of four antagonist classes. In three of these cases no structural data had previously been available. We used NMR spectroscopy to characterize FimH-antagonist interactions further by chemical shift perturbation. The analysis allowed a clear determination of the conformation of the tyrosine gate motif that is crucial for the interaction with aglycone moieties and was not obvious from X-ray structural data alone. Finally, ITC experiments provided insight into the thermodynamics of antagonist binding. In conjunction with the structural information from X-ray and NMR experiments the results provide a mechanism for the often-observed enthalpy-entropy compensation of FimH antagonists that plays a role in fine-tuning of the interaction.

DNABII proteins play a central role in UPEC biofilm structure

Most chronic and recurrent bacterial infections involve a biofilm component, the foundation of which is the extracellular polymeric substance (EPS). Extracellular DNA (eDNA) is a conserved and key component of the EPS of pathogenic biofilms. The DNABII protein family includes integration host factor (IHF) and histone-like protein (HU); both are present in the extracellular milieu. We have shown previously that the DNABII proteins are often found in association with eDNA and are critical for the structural integrity of bacterial communities that utilize eDNA as a matrix component. Here, we demonstrate that uropathogenic Escherichia coli (UPEC) strain UTI89 incorporates eDNA within its biofilm matrix and that the DNABII proteins are not only important for biofilm growth, but are limiting; exogenous addition of these proteins promotes biofilm formation that is dependent on eDNA. In addition, we show that both subunits of IHF, yet only one subunit of HU (HupB), are critical for UPEC biofilm development. We discuss the roles of these proteins in context of the UPEC EPS.

Changing profile and increasing antimicrobial resistance of uropathogenic bacteria in Madagascar

OBJECTIVES

We wanted to update the distribution of community-acquired uropathogens and to estimate their susceptibility profile to newly available antibiotics in Antananarivo (Madagascar).

MATERIALS AND METHODS

We conducted a 3-year preliminary study (2011-2013) on bacteria isolated from the urine of patients at the Laboratory of Training and Research in Medical Biology (Antananarivo).

RESULTS

Three hundred and fifty-seven pathogens were isolated: 234 (65.55%) Gram-negative bacilli and 123 (34.45%) Gram-positive cocci. The most commonly isolated bacteria were Escherichia coli (89 strains) followed by Staphylococcus aureus (48 strains). Thirty-three percent of Gram-negative bacilli were resistant to 3 CG. Forty percent of Klebsiella pneumoniae strains were significantly resistant to imipenem (P = 0.01).

CONCLUSIONS

The increased resistance to newly available antibiotics and the increased rate of Gram-positive cocci strains require a drastic surveillance of antibiotic resistance to ensure appropriate empirical treatment.

Incidence of antibiotics resistance among uropathogens in Omani children presenting with a single episode of urinary tract infection

Urinary tract infection (UTI) is one of the most common community-acquired infections. Different organisms can be the cause of UTI in children, with resistance to antibiotics becoming a significant problem in the choice of treatment. Worldwide studies have documented the prevalence of uropathogens in different countries. However, there is no previous study documenting the incidence of different uropathogens in Oman. We aim to report the most common uropathogens and their antibiotic sensitivity patterns in children presenting with documented, single episode UTI at a tertiary hospital in Oman. A retrospective analysis of all Omani children below 14 years who presented with a case of first documented UTI to SQUH between September 2008 and August 2012 was conducted. Data were obtained from the patients' electronic records in the hospital information system. Data were then analyzed using SSPS (Statistical Package for Social Sciences program, Version 20, IBM, Chicago, IL, USA). In the retrospective review of all urine cultures, 438 positive urine cultures were identified. Out of those, 208 (47.5%) belonged to children with their first episode of UTI. Thirty-three patients were excluded and 75 patients were included in the final analysis. Escherichia coli was the most frequently encountered uropathogen in our cohort (69%), followed by Klebsiella pneumoniae infection (17%). Nearly half (46.6%) of these two common organism were resistant to Cotrimoxazole, while 31% of them were resistant to Augmentin. Twenty-four percent of the E. coli and K. pneumoniae strains were resistant to Cefuroxime, and only 10% were resistant to nitrofurantoin. Both Augmentin and Cotrimoxazole should not be the first line antibiotics to treat UTI.

A Randomized, Double-Blind, Parallel-Group, Multicenter Clinical Study of Escherichia coli-Lyophilized Lysate for the Prophylaxis of Recurrent Uncomplicated Urinary Tract Infections

BACKGROUND

One strategy for managing recurrent uncomplicated urinary tract infections (UTIs) is prevention. This study tested OM-89S, a lyophilized lysate of 18 Escherichia coli strains manufactured using a modified lytic process.

METHODS

This was a randomized, double-blind trial in 451 female subjects with recurrent uncomplicated UTIs. Period 1 of the study tested 6 mg of OM-89S versus placebo (3 months), plus a 3-month observation. Period 2 of the study was a 3-month treatment period (each monthly cycle consisted of 6 mg of OM-89S daily for 10 days and placebo for 20 days, vs. 50 mg nitrofurantoin daily for 30 days), plus a 3-month observation.

RESULTS

There was no difference in the mean rate of UTI episodes between the OM-89S (0.66 ± 0.93) and placebo groups (0.63 ± 0.86; p = 0.95) in period 1. Similar findings were obtained for period 2. OM-89S was well-tolerated.

CONCLUSIONS

Our results did not demonstrate a preventive effect of OM-89S compared to placebo. This may be due to the low number of UTIs that occurred during the study, the high number of protocol violations, and/or the modified manufacturing process used for OM-89S.

Signature-tagged mutagenesis and co-infection studies demonstrate the importance of P fimbriae in a murine model of urinary tract infection

Escherichia coli is the leading cause of urinary tract infections (UTIs), one of the most common infections in humans. P fimbria was arguably the first proposed virulence factor for uropathogenic E. coli, based on the capacity of E. coli isolated from UTIs to adhere to exfoliated epithelial cells in higher numbers than fecal strains of E. coli. Overwhelming epidemiologic evidence has been presented for involvement of P fimbriae in colonization. It has been difficult, however, to demonstrate this requirement for uropathogenic strains in animal models of infections or in humans. In this study, a signature-tagged mutagenesis screen identified a P-fimbrial gene (papC) and 18 other genes as being among those required for full fitness of cystitis isolate E. coli F11. A P-fimbrial mutant was outcompeted by the wild-type strain in cochallenge in the murine model of ascending UTI, and this colonization defect could be complemented with the cloned pap operon. To our knowledge, this study is the first to fulfill molecular Koch's postulates in which a pathogenic strain was attenuated by mutation of pap genes and then complemented to restore fitness, confirming P fimbria as a virulence factor in a pathogenic clinical isolate.

Blocking yersiniabactin import attenuates extraintestinal pathogenic Escherichia coli in cystitis and pyelonephritis and represents a novel target to prevent urinary tract infection

The emergence and spread of extended-spectrum beta-lactamases and carbapenemases among common bacterial pathogens are threatening our ability to treat routine hospital- and community-acquired infections. With the pipeline for new antibiotics virtually empty, there is an urgent need to develop novel therapeutics. Bacteria require iron to establish infection, and specialized pathogen-associated iron acquisition systems like yersiniabactin, common among pathogenic species in the family Enterobacteriaceae, including multidrug-resistant Klebsiella pneumoniae and pathogenic Escherichia coli, represent potentially novel therapeutic targets. Although the yersiniabactin system was recently identified as a vaccine target for uropathogenic E. coli (UPEC)-mediated urinary tract infection (UTI), its contribution to UPEC pathogenesis is unknown. Using an E. coli mutant (strain 536ΔfyuA) unable to acquire yersiniabactin during infection, we established the yersiniabactin receptor as a UPEC virulence factor during cystitis and pyelonephritis, a fitness factor during bacteremia, and a surface-accessible target of the experimental FyuA vaccine. In addition, we determined through transcriptome sequencing (RNA-seq) analyses of RNA from E. coli causing cystitis in women that iron acquisition systems, including the yersiniabactin system, are highly expressed by bacteria during natural uncomplicated UTI. Given that yersiniabactin contributes to the virulence of several pathogenic species in the family Enterobacteriaceae, including UPEC, and is frequently associated with multidrug-resistant strains, it represents a promising novel target to combat antibiotic-resistant infections.

Clinical importance and epidemiology of quinolone resistance

The quinolone class of antimicrobial agents is one of most widely used classes of antimicrobial agents in outpatient and inpatient treatment. However, quinolone resistance in gram-positive and gram-negative bacteria has emerged and increased globally. This resistance limits the usefulness of quinolones in clinical practice. The review summarizes mechanisms of quinolone resistance and its epidemiology and implications in the most common clinical settings, urinary tract infections, respiratory tract infections, intraabdominal infections, skin and skin structure infections, and sexually transmitted diseases.

Expression of marA is remarkably increased from the early stage of development of fluoroquinolone-resistance in uropathogenic Escherichia coli

BACKGROUND

Analyses of efflux pumps overexpression and mutations in quinolone resistance determining region (QRDR) in early stage of development of resistance to fluoroquinolones (FQs) are valuable to discuss countermeasures against them. We induced levofloxacin (LVFX)-resistant strains from susceptible uropathogenic Escherichia coli in vitro to analyze the mechanisms of development of FQs-resistance.

METHODS

89 strains were exposed to discontinuous elevation of LVFX dose, and mRNA level of efflux pumps and their regulators as well as mutations developed in QRDR of LVFX-resistant strains were analyzed.

RESULTS

In 5 strains, a stepwise increase in MIC to LVFX (up to >128 μg/ml)was observed. Compared to the parent strains, additional mutations in QRDR were observed in the strains developing high MIC. Remarkable increase of marA expression was observed even in the early stage of LVFX-resistance development, and it lasted until high-level resistance was developed. On the other hand, moderate increase in acrB expression but only low increase in yhiU, yhiV, mdfA, tolC and sdiA were observed.

CONCLUSIONS

These results suggested that marA expression is a sensitive marker for early detection of development of LVFX-resistance.

Clinical spectrum of urine cultures positive for ESBL-producing Escherichia coli in hospitalized patients and impact on antibiotic use

OBJECTIVE

We wanted to describe the clinical features associated with urinalysis positive for ESBL-producing Escherichia coli and their impact on antibiotic use.

METHODS

We performed a prospective observational study in 13 French hospitals of the Paris area for 3 consecutive months. We included all patients with urine cultures positive for ESBL-producing E. coli.

RESULTS

One hundred and seventeen of the 218 patients (54%) presented with asymptomatic bacteriuria, 31 (14%) with cystitis, and 70 (32%) with a parenchymal infection. Nineteen patients with asymptomatic bacteriuria (16%) received antibiotics. Forty-one with parenchymal infections (59%) received a carbapenem. A carbapenem alternative could have been used in every patient treated with a carbapenem, according to antibiotic susceptibility testing results.

CONCLUSIONS

Urinary tract infections accounted for 46% of E. coli ESBL positive urinalysis. Fifty percent of parenchymal infections were treated with a carbapenem.

Evolution of the resistance to antibiotics of bacteria involved in urinary tract infections: a 7-year surveillance study

BACKGROUND

We conducted a retrospective analysis on the identification and antibiogram of all bacteria isolated from urine samples with microbiological confirmation of urinary tract infection (UTI) in a Spanish reference hospital over a 7-year period.

METHODS

A retrospective analysis was performed of the identification and antibiogram data.

RESULTS

A total of 31,758 uropathogens were isolated. Escherichia coli accounted for the majority (55.2%) of these, followed by Enterococcus faecalis (18.0%) and Klebsiella spp (10.3%). The highest E coli susceptibility rates were to imipenem (93.0%-99.8%), amikacin (97.3%-99.5%), nitrofurantoin (96.7%-98.9%), and fosfomycin (95.3%-100%), and the lowest were to cefuroxime (67.8%-86.4%), ciprofloxacin (61.2%-69.8%), and co-trimoxazole (55.0%-65.5%). We highlight the overall high activity of imipenem, piperacillin-tazobactam, nitrofurantoin, and fosfomycin on isolates versus the low activity of fluoroquinolones, co-trimoxazole, or cephalosporins. The activity of amoxicillin-clavulanic acid and fosfomycin decreased significantly over the 7-year study period.

CONCLUSIONS

Imipenem and piperacillin-tazobactam appear to be good options for the empiric treatment of UTI acquired in hospital or requiring hospitalization, whereas nitrofurantoin and fosfomycin can be first-choice antibiotics for the treatment of uncomplicated community-acquired cystitis. However, surveillance studies are required to detect resistance to these antibiotics, given that an increase in uropathogen resistance rates may contraindicate its future use in empiric UTI therapy.

Understanding the patterns of antibiotic susceptibility of bacteria causing urinary tract infection in West Bengal, India

Urinary tract infection (UTI) is one of the most common infectious diseases at the community level. In order to assess the adequacy of empirical therapy, the susceptibility of antibiotics and resistance pattern of bacteria responsible for UTI in West Bengal, India, were evaluated throughout the period of 2008-2013. The infection reports belonging to all age groups and both sexes were considered. Escherichia coli was the most abundant uropathogen with a prevalence rate of 67.1%, followed by Klebsiella spp. (22%) and Pseudomonas spp. (6%). Penicillin was least effective against UTI-causing E. coli and maximum susceptibility was recorded for the drugs belonging to fourth generation cephalosporins. Other abundant uropathogens, Klebsiella spp., were maximally resistant to broad-spectrum penicillin, followed by aminoglycosides and third generation cephalosporin. The antibiotic resistance pattern of two principal UTI pathogens, E. coli and Klebsiella spp. in West Bengal, appears in general to be similar to that found in other parts of the Globe. Higher than 50% resistance were observed for broad-spectrum penicillin. Fourth generation cephalosporin and macrolides seems to be the choice of drug in treating UTIs in Eastern India. Furthermore, improved maintenance of infection incident logs is needed in Eastern Indian hospitals in order to facilitate regular surveillance of the occurrence of antibiotic resistance patterns, since such levels continue to change.

Uncomplicated Urinary Tract Infections and Antibiotic Resistance-Epidemiological and Mechanistic Aspects

Uncomplicated urinary tract infections are typically monobacterial and are predominantly caused by Escherichia coli. Although several effective treatment options are available, the rates of antibiotic resistance in urinary isolates of E. coli have increased during the last decade. Knowledge of the actual local rates of antibiotic resistant pathogens as well as the underlying mechanisms are important factors in addition to the geographical location and the health state of the patient for choosing the most effective antibiotic treatment. Recommended treatment options include trimethoprim alone or in combination with sulfamethoxazol, fluoroquinolones, β-lactams, fosfomycin-trometamol, and nitrofurantoin. Three basic mechanisms of resistance to all antibiotics are known, i.e., target alteration, reduced drug concentration and inactivation of the drug. These mechanisms—alone or in combination—contribute to resistance against the different antibiotic classes. With increasing prevalence, combinations of resistance mechanisms leading to multiple drug resistant (mdr) pathogens are being detected and have been associated with reduced fitness under in vitro situations. However, mdr clones among clinical isolates such as E. coli sequence type 131 (ST131) have successfully adapted in fitness and growth rate and are rapidly spreading as a worldwide predominating clone of extraintestinal pathogenic E. coli.

Efficacy and safety of fosfomycin-trometamol in the prophylaxis for transrectal prostate biopsy. Prospective randomized comparison with ciprofloxacin

OBJECTIVE

Prostate biopsy is the standardized diagnostic method for prostate cancer. However, although there is not a standardized protocol, there are recommendations in order to reduce the incidence of complications. The objective of the present work is to assess the efficacy and safety of antibiotic prophylaxis in the prostate biopsy by comparing two antibiotic regimes: two doses of fosfomycin-trometamol 3g (FMT) every 48 hours with 10 doses of oral ciprofloxacin 500 mg every 12 hours during 5 days.

MATERIAL AND METHODS

Randomized prospective study was performed with 671 patients who had undergone to walking transrectal ultrasound guided prostate biopsy. Patients of group A (n=312) were treated with ciprofloxacin, and patients of group B (n=359) with FMT. Efficacy and tolerability of two prophylactic regimes were compared. Urine culture was carried out at 2 weeks after biopsy. Initially, patients with asymptomatic bacteriuria were not treated with antibiotics; urine culture was repeated after 1 month, persistent bacteriuria was treated according to antibiogram.

RESULTS

No differences between groups were found in age (P=.78), cancer presence (P=.9) or number of biopsy cylinders (P=.93). The mean number of cores obtained was 11.3 ± 3.25 (range 6-20). Digestive intolerance was observed for 9 patients (2.9%) of group A and 10 patients (2.8%) in group B. One patient (.3%) of group A showed severe allergic reaction. In total, 167 patients (24.6%) had complications: 16 (2.4%) fever, 47 (6.9%) hemospermia, 81 (11.9%) hematuria, 7 (1%) rectal bleeding and 16 (2.4%) urinary retention. No statistically differences between groups were observed (27.6% vs. 22.6%; P=.17). However, hemospermia was more frequent in group A (9.9% vs. 4.5%; P=.006). Bacteriuria after biopsy was detected in 44 patients (6.6%), being more frequent in group B patients (4.2% vs. 8.6%; P=.02) although a higher number of second treatment cycles were not needed (53.9% vs. 29%; P=.17). The likelihood of resistance to ciprofloxacin in patients with bacteriuria in A was greater than that of FMT in B (69.2% vs. 41.9%; P=.0004).

CONCLUSIONS

Antibiotic prophylaxis with FMT (2 doses of 3g) in prostate biopsy is an alternative as effective and safe as ciprofloxacin (10 doses of 500 mg), which carries lower rate of resistance. According to our experience, this drug is a safe, well-tolerated, and easily manageable prophylactic option, facilitating patient compliance. More prospective multicenter studies are necessary to confirm these findings.

Influence of induced ciprofloxacin resistance on efflux pump activity of Klebsiella pneumoniae

OBJECTIVE

The efflux pump (EP) is one of the major mechanisms of antibiotic resistance in Klebsiella pneumoniae. However, there are few reports on the effect of the abuse of antibiotic use on the activity of EPs. To determine whether the use of low efficacy antibiotics has any effect on the activity of EPs and induces drug resistance in K. pneumoniae, we investigated the effect of ciprofloxacin on the activity of EPs in K. pneumoniae strains.

METHODS

Sixteen susceptible K. pneumoniae strains were isolated from patients and their minimum inhibitory concentrations (MICs) of ciprofloxacin were measured in the absence and presence of the pump inhibitor carbonyl cyanide m-chlorophenyl hydrazone (CCCP). The strains were then induced with a gradient of ciprofloxacin until the MICs of the strains showed no further increase, to obtain induced resistant strains. The EP activities of the strains before and after induction were compared using EP inhibition and ethidium bromide (EtBr) accumulation assays.

RESULTS

The MIC values of the strains were 16‒256 times higher after induction than before induction. In the presence of CCCP, the MIC values of 50% of the induced strains were 2‒4-fold lower than that in the absence of this inhibitor. The EtBr accumulation assay showed that the fluorescence of EtBr in the induced cells was lower than that in the cells before induction.

CONCLUSIONS

EPs are widespread in susceptible and drug-resistant K. pneumoniae strains. Induction with ciprofloxacin may increase the activity of EPs in K. pneumoniae. The EtBr accumulation assay is more sensitive than the EP inhibition assay in evaluating the activity of EPs in K. pneumoniae.

Mecillinam resistance and outcome of pivmecillinam treatment in uncomplicated lower urinary tract infection in women

Pivmecillinam (PIV) is a first-line antimicrobial for treatment of lower urinary tract infection in women (LUTIW). Mecillinam, the active substance of PIV, is bactericidal mainly against gram-negative uropathogens, whereas gram-positive species are considered intrinsically resistant. However, successful treatment of LUTIW caused by Staphylococcus saprophyticus has been reported, but more rarely for other gram-positive species. The aim of this study was to compare clinical and bacteriological outcome of PIV vs placebo treatment among uropathogens with special focus on mecillinam-resistant isolates. We analysed data from a prospective, multicentre, placebo-controlled, primary health care, therapy study performed in Sweden in 1995–1998 that included 1143 women with symptoms suggestive of LUTIW. Urine cultures were collected and symptoms registered at inclusion and at follow-up visits. Overall, the efficacy of PIV was superior to that of placebo. Clinical and bacteriological outcomes of PIV treatment were similar for S. saprophyticus, Escherichia coli as for most other uropathogens irrespective of their susceptibility to mecillinam. However, the occurrence of enterococci increased nearly fivefold shortly post PIV treatment, although with mild symptoms and a high spontaneous eradication. As susceptibility to mecillinam in vitro did not predict bacteriological and clinical outcome of PIV treatment, we suggest that the present breakpoints for mecillinam should be revised.

Pharmacodynamic profiling of commonly prescribed antimicrobial drugs against Escherichia coli isolates from urinary tract

Since antimicrobial resistance among uropathogens against current first line agents has affected the management of severe urinary tract infection, we determined the likelihood that antibiotic regimens achieve bactericidal pharmacodynamic exposures using Monte Carlo simulation for five antimicrobials (ciprofloxacin, ceftriaxone, piperacillin/tazobactam, ertapenem, and meropenem) commonly prescribed as initial empirical treatment of inpatients with severe community acquired urinary tract infections. Minimum inhibitory concentration determination by Etest was performed for 205 Brazilian community urinary tract infection Escherichia coli strains from 2008 to 2012 and 74 E. coli bloodstream strains recovered from a surveillance study. Pharmacodynamic exposure was modeled via a 5000 subject Monte Carlo simulation. All isolates were susceptible to ertapenem and meropenem. Piperacillin/tazobactam, ceftriaxone and ciprofloxacin showed 100%, 97.5% and 83.3% susceptibility among outpatient isolates and 98.6%, 75.7% and 64.3% among inpatient isolates, respectively. Against outpatient isolates, all drugs except ciprofloxacin (82.7% in aggressive and 77.6% in conservative scenarios) achieved high cumulative fraction of response: carbapenems and piperacillin/tazobactam cumulative fraction of responses were close to 100%, and ceftriaxone cumulative fraction of response was 97.5%. Similar results were observed against inpatients isolates for carbapenems (100%) and piperacillin/tazobactam (98.4%), whereas ceftriaxone achieved only 76.9% bactericidal cumulative fraction of response and ciprofloxacin 61.9% (aggressive scenario) and 56.7% (conservative scenario) respectively. Based on this model, standard doses of beta-lactams were predicted to deliver sufficient pharmacodynamic exposure for outpatients. However, ceftriaxone should be avoided for inpatients and ciprofloxacin empirical prescription should be avoided in both inpatients and outpatients with complicated urinary tract infection.

Cystitis: antibiotic prescribing, consultation, attitudes and opinions

BACKGROUND

Despite stable overall antibiotic use between 2007 and 2011 in The Netherlands, use of nitrofurantoin and trimethoprim increased by 32%. The background of this increased antibiotic use against uropathogens is unknown.

OBJECTIVES

To determine whether increased use of urinary tract infection antibiotics is caused by changes in patients' consultation or physicians' prescribing behaviour and to investigate attitudes and opinions of women with respect to cystitis management and antibiotics.

METHODS

Consultation and prescribing for International Classification of Primary Care (ICPC) codes U01 (dysuria), U02 (frequency), U05 (other urination problems), U70 (pyelonephritis) and U71 (cystitis) were determined from 2007 to 2010, using routinely collected primary health care data. Separately, behaviour of women with respect to managing cystitis, consultation and opinions towards (delayed) antibiotic treatment were studied using questionnaires in 2012.

RESULTS

Consultation for U02 and U71 significantly increased from 93 to 114/1000 patient-years from 2007 to 2010; proportion of episodes in which an antibiotic was prescribed remained constant. Questionnaires revealed that urination problems and pain were dominant complaints of cystitis; pain medication, however, was not adequately used. One-third of women directly consult upon first symptoms, whereas the majority awaits an average of 4 days. Sixty-six per cent of women report to be willing to postpone antibiotic use.

CONCLUSION

Increased use of urinary tract infection antibiotics may be caused by increased consultation for cystitis in primary care. Future research should focus on the outcomes of adequate pain medication, enhanced diagnostic procedures and of delaying antibiotic use in cystitis management.

Uncomplicated Urinary Tract Infections in Women in a Sao Paulo Quaternary Care Hospital: Bacterial Spectrum and Susceptibility Patterns

Uncomplicated urinary tract infections (UTI) in women are very common. Regular analysis of bacterial flora is important to formulate updated guidelines. The objective of this study is to determine and compare the microbiology of UTIs and their susceptibility patterns in a quaternary care hospital. In a seven-year review, the urine culture results of 480 female patients with uncomplicated UTIs were analyzed. Patients were divided into three groups according to their diagnosis and treatment characteristics: Group 1, cystitis at outpatient basis; group 2, cystitis at the Emergency Unit; and group 3, pyelonephritis. Group 1 included older patients, with a higher incidence of concomitant diabetes mellitus and recurrent UTIs. E. coli was the most common pathogen, responsible for 75.1% of cases, mainly for pyelonephritis (87.3%). Of the oral antimicrobials tested for cystitis, amoxicillin/clavulanate and nitrofurantoin had the highest susceptibility profiles (84.4% and 87.3%, respectively). For E. coli only, their susceptibility profiles were as high as 90.8% and 97.4%, respectively. For pyelonephritis treatment, fluoroquinoles had a susceptibility profile <90%, while ceftriaxone and gentamicin had susceptibility >90%. Uncomplicated UTI treatment is becoming more challenging because the susceptibility profiles of oral antimicrobials are increasingly resistant. In our environment, cystitis can still be managed with nitrofurantoin. Uncomplicated pyelonephritis should be managed with ceftriaxone or gentamicin.

Antibiotic treatment of acute uncomplicated cystitis based on rapid urine test and local epidemiology: lessons from a primary care series

Background

Acute uncomplicated cystitis (AUC) is an ideal target of optimization for antibiotic therapy in primary care. Because surveillance networks on urinary tract infections (UTI) mix complicated and uncomplicated UTI, reliable epidemiological data on AUC lack. Whether the antibiotic choice should be guided by a rapid urine test (RUT) for leukocytes and nitrites has not been extensively studied in daily practice. The aim of this primary care study was to investigate local epidemiology and RUT-daily use to determine the optimal strategy.

Methods

General practitioners included 18–65 years women with symptoms of AUC, performed a RUT and sent urines for analysis at a central laboratory. Different treatment strategies were simulated based on RUT and resistance results.

Results

Among 347 enrolled patients, 78% had a positive urine culture. Escherichia coli predominated (71%) with high rates of susceptibility to nitrofurantoin (100%), fosfomycin (99%), ofloxacin (97%), and even pivmecillinam (87%) and trimethoprim-sulfamethoxazole (87%). Modelization showed that the systematic use of RUT would reduce by 10% the number of patients treated. Fosfomycin for patients with positive RUT offered a 90% overall bacterial coverage, compared to 98% for nitrofurantoin. 95% for ofloxacin, 86% for trimethoprim-sulfamethoxazole and 78% for pivmecillinam.

Conclusion

Local epidemiology surveillance data not biased by complicated UTI demonstrates that the worldwide increase in antibiotic resistance has not affected AUC yet. Fosfomycin first line in all patients with positive RUT seems the best treatment strategy for AUC, combining good bacterial coverage with expected low toxicity and limited effect on fecal flora.

Trial registration

The current study was registered at clinicaltrials.gov (NCT00958295)

Inhibitors of TonB function identified by a high-throughput screen for inhibitors of iron acquisition in uropathogenic Escherichia coli CFT073

The urinary tract is one of the most common sites of infection in humans, and uropathogenic Escherichia coli (UPEC) is the main causative agent of urinary tract infections. Bacteria colonizing the urinary tract face extremely low iron availability. To counteract this, UPEC expresses a wide variety of iron acquisition systems. To exploit iron acquisition in UPEC as a global target for small-molecule inhibition, we developed and carried out a whole-cell growth-based high throughput screen of 149,243 compounds. Our primary assay was carried out under iron-limiting conditions. Hits in the primary screen were assayed using two counterscreens that ruled out iron chelators and compounds that inhibit growth by means other than inhibition of iron acquisition. We determined dose-response curves under two different iron conditions and purchased fresh compounds for selected hits. After retesting dose-response relationships, we identified 16 compounds that arrest growth of UPEC only under iron-limiting conditions. All compounds are bacteriostatic and do not inhibit proton motive force. A loss-of-target strategy was employed to identify the cellular target of these inhibitors. Two compounds lost inhibitory activity against a strain lacking TonB and were shown to inhibit irreversible adsorption of a TonB-dependent bacteriophage. Our results validate iron acquisition as a target for antibacterial strategies against UPEC and identify TonB as one of the cellular targets.

Half of women will suffer at least one episode of urinary tract infection (UTI) during their lifetime. The current treatment for UTI involves antibiotic therapy. Resistance to currently used antibiotics has steadily increased over the last decade, generating a pressing need for the development of new therapeutic agents. Since iron is essential for colonization and scarce in the urinary tract, targeting iron acquisition would seem to be an attractive strategy. However, the multiplicity and redundancy of iron acquisition systems in uropathogenic Escherichia coli (UPEC) make it difficult to pinpoint a specific cellular target. Here, we identified 16 iron acquisition inhibitors through a whole-cell high-throughput screen, validating iron acquisition as a target for antibacterial strategies against UPEC. We also identified the cellular target of two of the inhibitors as the TonB system.

Prevalence and persistence of Escherichia coli in the airways of cystic fibrosis patients - an unrecognized CF pathogen?

Cystic fibrosis (CF) patients suffer from chronic recurrent bacterial airway infections, which eventually lead to reduced life expectancy. Escherichia coli has not been considered as a CF pathogen. A total of 176 patients were observed over 5.6 years on average from 2002 to 2009 in two CF centers in Muenster, Germany. Sputum and throat swab cultures were screened for E. coli. E. coli isolates were analyzed for clinical microbiologic characteristics as well as strain identity, clonal distribution and phenotypic variability. In 45 patients (25.6%) E. coli was cultured at least once, mostly at medium to high bacterial load and primarily from patients less than 5 and older than 8 years. In 19 patients (10.8%) the same E. coli strain was isolated at least 3 times within a period of more than 6 months, with a mean persistence of 29 months. Multi-locus sequence typing revealed a distinctively strong association of CF E. coli with the B2 major clonal group. During persistence, long-term colonizing strains exhibited phenotypic variability known for typical CF pathogens such as surface capsule overproduction and changes in colony size or hemolytic activity. E. coli was occasionally or persistently isolated in a quarter of CF patients, mostly in very young or older patients. The relatively high bacterial load of E. coli colonization, the distinct association with the highly virulent extra-intestinal B2 clonal group and phenotypic variability in the long-term colonizing strains suggests a previously unrecognized clinical significance of E. coli as a CF pathogen.

Escherichia coli in Europe: an overview

Escherichia coli remains one of the most frequent causes of several common bacterial infections in humans and animals. E. coli is the prominent cause of enteritis, urinary tract infection, septicaemia and other clinical infections, such as neonatal meningitis. E. coli is also prominently associated with diarrhoea in pet and farm animals. The therapeutic treatment of E. coli infections is threatened by the emergence of antimicrobial resistance. The prevalence of multidrug-resistant E. coli strains is increasing worldwide principally due to the spread of mobile genetic elements, such as plasmids. The rise of multidrug-resistant strains of E. coli also occurs in Europe. Therefore, the spread of resistance in E. coli is an increasing public health concern in European countries. This paper summarizes the current status of E. coli strains clinically relevant in European countries. Furthermore, therapeutic interventions and strategies to prevent and control infections are presented and discussed. The article also provides an overview of the current knowledge concerning promising alternative therapies against E. coli diseases.

From physiology to pharmacy: developments in the pathogenesis and treatment of recurrent urinary tract infections

Urinary tract infections (UTIs) are common, and over half of women report having had at least one in their lifetime. Nearly a third of these women experience recurrent UTI episodes, but the mechanisms of these recurrences are not fully elucidated. Frequent use of antimicrobials for treatment and prevention of UTIs and other infections has contributed to the evolution of multidrug-resistant microorganisms globally. This is a looming worldwide crisis that has created an urgent need for novel strategies for the treatment and prevention of UTIs. Furthering our understanding of the mechanisms of recurrent UTIs, from both host and bacterial perspectives, will be paramount in developing targeted management strategies. In this review, we discuss recent findings regarding recurrent UTIs in women, including progress in our understanding of the mechanisms of recurrence as well as emerging treatments.

Inhibition of urease activity in the urinary tract pathogen Staphylococcus saprophyticus

Urease is a virulence factor for the Gram-positive urinary tract pathogen Staphylococcus saprophyticus. The susceptibility of this enzyme to chemical inhibition was determined using soluble extracts of Staph. saprophyticus strain ATCC 15305. Acetohydroxamic acid (Ki = 8.2 μg ml(-1) = 0.106 mmol l(-1) ) and DL-phenylalanine hydroxamic acid (Ki = 21 μg ml(-1) = 0.116 mmol l(-1) ) inhibited urease activity competitively. The phosphorodiamidate fluorofamide also caused competitive inhibition (Ki = 0.12 μg ml(-1) = 0.553 μmol l(-1) = 0.000553 mmol l(-1) ), but the imidazole omeprazole had no effect. Two flavonoids found in green tea extract [(+)-catechin hydrate (Ki = 357 μg ml(-1) = 1.23 mmol l(-1) ) and (-)-epigallocatechin gallate (Ki = 210 μg ml(-1) = 0.460 mmol l(-1) )] gave mixed inhibition. Acetohydroxamic acid, DL-phenylalanine hydroxamic acid, fluorofamide, (+)-catechin hydrate and (-)-epigallocatechin gallate also inhibited urease activity in whole cells of strains ATCC 15305, ATCC 35552 and ATCC 49907 grown in a rich medium or an artificial urine medium. Addition of acetohydroxamic acid or fluorofamide to cultures of Staph. saprophyticus in an artificial urine medium delayed the increase in pH that normally occurs during growth. These results suggest that urease inhibitors may be useful for treating urinary tract infections caused by Staph. saprophyticus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The enzyme urease is a virulence factor for the Gram-positive urinary tract pathogen Staphylococcus saprophyticus. We have shown that urease activity in cell-free extracts and whole bacterial cells is susceptible to inhibition by hydroxamates, phosphorodiamidates and flavonoids, but not by imidazoles. Acetohydroxamic acid and fluorofamide in particular can temporarily delay the increase in pH that occurs when Staph. saprophyticus is grown in an artificial urine medium. These results suggest that urease inhibitors may be useful as chemotherapeutic agents for the treatment of urinary tract infections caused by this micro-organism.

Allosteric coupling in the bacterial adhesive protein FimH

The protein FimH is expressed by the majority of commensal and uropathogenic strains of Escherichia coli on the tips of type 1 fimbriae and mediates adhesion via a catch bond to its ligand mannose. Crystal structures of FimH show an allosteric conformational change, but it remains unclear whether all of the observed structural differences are part of the allosteric mechanism. Here we use the protein structural analysis tool RosettaDesign combined with human insight to identify and synthesize 10 mutations in four regions that we predicted would stabilize one of the conformations of that region. The function of each variant was characterized by measuring binding to the ligand mannose, whereas the allosteric state was determined using a conformation-specific monoclonal antibody. These studies demonstrated that each region investigated was indeed part of the FimH allosteric mechanism. However, the studies strongly suggested that some regions were more tightly coupled to mannose binding and others to antibody binding. In addition, we identified many FimH variants that appear locked in the low affinity state. Knowledge of regulatory sites outside the active and effector sites as well as the ability to make FimH variants locked in the low affinity state may be crucial to the future development of novel antiadhesive and antimicrobial therapies using allosteric regulation to inhibit FimH.

Analysis of the spectrum and antibiotic resistance of uropathogens in vitro: results based on a retrospective study from a tertiary hospital

BACKGROUND

Antibiotic resistance of uropathogens in urinary tract infections (UTIs) is increasing worldwide. This study aimed to compare the spectrum and antimicrobial resistance of uropathogens in community-acquired UTIs (CAUTIs) and nosocomial-acquired UTIs (NAUTIs) at a tertiary hospital in China.

METHODS

Retrospective analysis of uropathogens from UTI patients was performed at Zhong Da Hospital.

RESULTS

A total of 1129 strains was isolated from 653 community-acquired and 476 nosocomial-acquired infections. Escherichia coli was the most common uropathogen, accounting for 55.9% of the CAUTIs and 27.1% of the NAUTIs. Among the CAUTIs, Escherichia coli was followed in prevalence by Enterococcus spp (12.9%) and Proteus mirabilis (3.7%). Among the NAUTIs, Escherichia coli was followed by Enterococcus spp (15.3%) and Klebsiella pneumoniae (6.9%). The proportion of fungi in the NAUTIs (23.7%) was higher than that in the CAUTIs (3.1%) (P < .05). Extended-spectrum β-lactamase-producing strains of E coli accounted for 70.6% of the NAUTIs and 47.3% of the CAUTIs. Carbapenems, amikacin, and nitrofurantoin were active agents against E coli. The resistance rates of E coli to cephalosporins, ampicillin, ampicillin/sulbactam, quinolones, and gentamicin were higher in the NAUTIs than in the CAUTIs (P < .05).

CONCLUSION

The distribution of species was different between CAUTIs and NAUTIs. Higher antibiotic resistance rates were observed in the NAUTIs than in the CAUTIs.

Immunization with the yersiniabactin receptor, FyuA, protects against pyelonephritis in a murine model of urinary tract infection

Urinary tract infections (UTI) are common and represent a substantial economic and public health burden. Roughly 80% of these infections are caused by a heterogeneous group of uropathogenic Escherichia coli (UPEC) strains. Antibiotics are standard therapy for UTI, but a rise in antibiotic resistance has complicated treatment, making the development of a UTI vaccine more urgent. Iron receptors are a promising new class of vaccine targets for UTI, as UPEC require iron to colonize the iron-limited host urinary tract and genes encoding iron acquisition systems are highly expressed during infection. Previously, three of six UPEC siderophore and heme receptors were identified as vaccine candidates by intranasal immunization in a murine model of ascending UTI. To complete the assessment of iron receptors as vaccine candidates, an additional six UPEC iron receptors were evaluated. Of the six vaccine candidates tested in this study (FyuA, FitA, IroN, the gene product of the CFT073 locus c0294, and two truncated derivatives of ChuA), only FyuA provided significant protection (P = 0.0018) against UPEC colonization. Intranasal immunization induced a robust and long-lived humoral immune response. In addition, the levels of FyuA-specific serum IgG correlated with bacterial loads in the kidneys [Spearman's rank correlation coefficient ρ(14) = -0.72, P = 0.0018], providing a surrogate of protection. FyuA is the fourth UPEC iron receptor to be identified from our screens, in addition to IutA, Hma, and IreA, which were previously demonstrated to elicit protection against UPEC challenge. Together, these iron receptor antigens will facilitate the development of a broadly protective, multivalent UTI vaccine to effectively target diverse strains of UPEC.

Prescriber and Patient Responsibilities in Treatment of Acute Respiratory Tract Infections — Essential for Conservation of Antibiotics

Inappropriate antibiotic use in normally self-limiting acute respiratory tract infections (RTIs), such as sore throat and the common cold, is a global problem and an important factor for increasing levels of antibiotic resistance. A new group of international experts—the Global Respiratory Infection Partnership (GRIP)—is committed to addressing this issue, with the interface between primary care practitioners and their patients as their core focus. To combat the overuse of antibiotics in the community, and facilitate a change from prescribing empiric antibiotic treatment towards cautious deferment combined with symptomatic relief, there is a need to introduce and enhance evidence-based dialogue between primary care practitioners and their patients. Communication with patients should focus on the de-medicalisation of self-limiting viral infections, which can be achieved via a coherent globally endorsed framework outlining the rationale for appropriate antibiotic use in acute RTIs in the context of antibiotic stewardship and conservancy. The planned framework is intended to be adaptable at a country level to reflect local behaviours, cultures and healthcare systems, and has the potential to serve as a model for change in other therapeutic areas.

D-mannose powder for prophylaxis of recurrent urinary tract infections in women: a randomized clinical trial

PURPOSE

To test whether D-mannose powder is effective for recurrent urinary tract infection (UTI) prevention.

MATERIALS AND METHODS

After initial antibiotic treatment of acute cystitis, 308 women with history of recurrent UTI and no other significant comorbidities were randomly allocated to three groups. The first group (n = 103) received prophylaxis with 2 g of D-mannose powder in 200 ml of water daily for 6 months, the second (n = 103) received 50 mg Nitrofurantoin daily, and the third (n = 102) did not receive prophylaxis.

RESULTS

Overall 98 patients (31.8%) had recurrent UTI: 15 (14.6) in the D-mannose group, 21 (20.4) in Nitrofurantoin group, and 62 (60.8) in no prophylaxis group, with the rate significantly higher in no prophylaxis group compared to active groups (P < 0.001). Patients in D-mannose group and Nitrofurantoin group had a significantly lower risk of recurrent UTI episode during prophylactic therapy compared to patients in no prophylaxis group (RR 0.239 and 0.335, P < 0.0001). In active groups, 17.9% of patients reported side effects but they were mild and did not require stopping the prophylaxis. Patients in D-mannose group had a significantly lower risk of side effects compared to patients in Nitrofurantoin group (RR 0.276, P < 0.0001), but the clinical importance of this finding is low because Nitrofurantoin was well tolerated.

CONCLUSIONS

In our study, D-mannose powder had significantly reduced the risk of recurrent UTI which was no different than in Nitrofurantoin group. More studies will be needed to validate the results of this study, but initial findings show that D-mannose may be useful for UTI prevention.

Antibiograms from community-acquired uropathogens in Gulu, northern Uganda--a cross-sectional study

Background

Urinary tract infections (UTI) are common in clinical practice and empirical treatment is largely employed due to predictability of pathogens. However, variations in antibiotic sensitivity patterns do occur, and documentation is needed to inform local empirical therapy. The current edition of the Uganda Clinical Guidelines recommends amoxicillin or cotrimoxazole as choice drugs for empirical treatment of community-acquired UTI. From our clinical observations, we suspected that this recommendation was not effective in our setting. In order to examine validity, we sought to identify bacteria from community-acquired infections and determine their susceptibility against these antibiotics plus a range of potentially useful alternatives for treatment of UTI.

Methods

A cross-sectional study of mid-stream urine collected from 339 symptomatic patients over a three-month period at Gulu regional referral hospital. Qualitative culture and identification of bacteria and antibiotic sensitivity testing using the modified Kirby-Bauer disk diffusion method was done. Participants’ demographic and clinical characteristics were collected using a standard form. Results were analyzed by simple proportions among related variables and confidence intervals computed using binomial exact distribution.

Results

Eighty two cultures were positive for UTI. Staphylococcus spp (46.3%) and Escherichia coli (39%) were the most common pathogens. There was high resistance to cotrimoxazole (73.2%), nalidixic acid (52.4%) and amoxicillin (51.2%). The most favorable antibiograms were obtained with gentamicin, amoxicillin-clavulanate and levofloxacin where 85.4%, 72.0%, 67.1% of isolates respectively, were either sensitive or intermediate. Only 51% of isolates were sensitive to ciprofloxacin.

Conclusion

There was high resistance to most antibiotics tested in this study. The recommendations contained in the current edition of the Uganda Clinical Guidelines are not in tandem with antibiotic sensitivity pattern of uropathogens seen in our setting. Amoxicillin-clavulanate or gentamicin should be considered for replacement of amoxicillin and cotrimoxazole for empirical treatment of UTI in our setting.

Aetiology and antibiotic resistance patterns of urinary tract infections in the elderly: a 6-month study

Urinary tract infections (UTIs) are a common cause of bacteraemia in the elderly and are associated with a high probability of hospitalization. Despite the impact of UTIs on health status and quality of life, a limited number of studies have evaluated their aetiology in this population. This study aimed to evaluate the microbial aetiology and pattern of susceptibility of bacteria causing UTIs in the elderly. For this purpose, a retrospective cohort study of elderly residents (n = 472, aged >65 years) in 14 nursing homes in Milan (Italy) and its province was performed. Globally, 393 micro-organisms from 328 samples were isolated: Escherichia coli was the most prevalent (44.8 %), followed by Proteus mirabilis (20.4 %), Providencia spp. (8.9 %), Klebsiella spp. (6.4 %) and Pseudomonas aeruginosa (4.6 %). Enterococci were the most frequently isolated Gram-positive organisms (7.4 %). Almost all Enterobacteriaceae were susceptible to nitrofurantoin, carbapenems and amikacin. Extended-spectrum β-lactamases were detected in 42.1 % of isolates. The most active antibiotics against P. aeruginosa were colistin, amikacin and piperacillin/tazobactam. All Gram-positive organisms were susceptible to glycopeptides and linezolid, and 90 % were susceptible to nitrofurantoin. Fluoroquinolones showed a limited activity against all the tested micro-organisms. Escherichia coli remains the major micro-organism responsible for UTIs in older people, although to a lesser extent than in a younger population. The high rates of resistance observed in this study make careful use of antibiotics advisable to limit further development of resistance.

[Randomized comparative study for the assessment of a new therapeutic schedule of fosfomycin trometamol in postmenopausal women with uncomplicated lower urinary tract infection]

OBJECTIVES

To compare two therapeutic regimes in terms of bacterial eradication of post-menopausal with uncomplicated acute cystitis who complete antibiotic treatment.

MATERIALS AND METHOD

A multicenter, randomized, prospective and controlled study between two short antibiotic regimes: fosfomycin trometamol (FMT) 3g, 2 doses separated by 72hours and ciprofloxacin 250mg every 12hours for 3 days. A total of 118 post-menopausal women were enrolled in the study. They underwent an initial urine culture to know the responsible microorganism and susceptibility to treatment. This was repeated 5-7 days and 4 weeks after the treatment to evaluate bacterial eradication. Clinical symptoms and treatment safety were also evaluated.

RESULTS

There were microbiological data at the onset of the treatment in 82 women (69.49%). Of these, 27 did not have positive culture at the first visit (30.51%), 76 (64.41%) fulfilled all the protocol requirements and adverse effects from the treatment were collected in 113 (95.76%) of the patients enrolled in the study. The germs isolated most frequently were Escherichia coli (E. coli) (76.83%), Klebsiella pneumoniae (K. pneumoniae) (7.32%), Proteus mirabilis (P. mirabilis) (4.89%) and Enterococo sp. (3.66%). In terms of efficacy, no differences were detected in the proportion of patients who achieved bacterial eradication between the two study arms: 62.16% of the patients who received FMT and 58.97% of those treated with ciprofloxacin (chi-square, p=0.78). The proportion of patients who achieved clinical cure was also similar (86.49% for FMT and 82.05% for ciprofloxacin; square, p=0.59). These results indicate similar efficacy of both antibiotics in the treatment of uncomplicated lower tract urinary infection in post-menopausal women. In regards to safety data, the proportion of global adverse effects associated to the treatments was 3.45% for FMT and 9.09% for ciprofloxacin. Treatment compliance was 100% for FMT and 83.64% for ciprofloxacin.

CONCLUSIONS

The FMT administered at a dose of 3g every 72hours (2 total doses) and ciprofloxacin at a dose of 250mg every 12hours during 3 days (6 total doses) have a comparable efficacy profile in lower tract urinary infection in post-menopausal women who adequately comply with the treatment, also having comparable safety. The FMT has a better antimicrobial susceptibility profile and better rate of treatment compliance.