Urinary Tract Pathogens Research Articles

<i>In Vitro</i> Activity of Cephalexin against Community-Acquired Urinary <i>Escherichia coli</i>, <i>Klebsiella</i> and <i>Proteus</i> species Isolates

Problem statement: Resistance among urinary tract pathogens to conventional antibiotics has been considered a health problem worldwide. The aim of this study was to evaluate the in vitro activity of cephalexin on urinary enterobacterial isolates. Approach: Patients with community-acquired urinary tract infections were microbiologically investigated. Urine specimens were collected from each patient. The specimens were cultured on bacteriological media. The isolated urinary pathogens were subjected to antibiotic sensitivity test using modified Kirby-Bauer Disc diffusion method. The method was judged by the National Committee for Clinical Laboratories Standards (NCCLS). Results: A total of 140 enterobacterial urinary isolates were recovered. Of these 93 (66.4%) were identified as E. coli, 20 (14.3%) as Klebsiella spp. and 12 (8.6%) as Proteus spp. The results showed that urinary enterobacterial pathogens had a high rate of resistance to cephalexin amounting to 75 (53.6%), whereas susceptible and intermediate rates were 34 (24.3%) and 31 (22.1%) respectively. Conclusion: It was concluded that E. coli are the predominant organisms isolated from subjects sampled. High resistance to cephalexin activity was noticed with Klebsiella spp isolates.

Antimicrobial susceptibility patterns of community-acquired uropathogens in Tehran, Iran

Antibiotic resistance of urinary tract pathogens has increased worldwide. Knowledge of the antibiotic resistance patterns of uropathogens in specific geographical locations is an important factor for choosing an appropriate empirical antimicrobial treatment. The aim of this study was to provide information regarding local resistance patterns of urinary pathogens to the commonly used antibiotics in Tehran, Iran. Urine samples collected and submitted to two pathobiology laboratories in Tehran were identified by conventional methods over a period of three years (December 2006 to May 2009). Antimicrobial resistance testing was performed by the standard disk diffusion technique in accordance with the recommendations of the Clinical and Laboratory Standards Institute. Of the total 13,333 mid-stream urine samples collected from suspected cases of urinary tract infection, 840 (6.3%) were positive for pathogenic bacteria. Escherichia coli (E. coli) was the most common isolate (68.8%) followed by Proteus spp. (12.4%), and Klebsiella spp. (9.6%). E. coli isolates were mostly susceptible to nitrofurantoin (71.3%), followed by ciprofloxacin (68.1%); however, only 38.2% of E. coli isolates were susceptible to trimethoprim-sulfamethoxazole. Nitrofurantoin may be considered as a first-line empiric antibacterial agent for urinary tract infections in outpatients in Tehran, Iran.

A Single-Center Experience of Antimicrobial Resistance Patterns in Pediatric Urinary Tract Infection

Objective: To assess the prevalence of urinary tract pathogens and their resistance patterns against antimicrobial agents in a single center. Patients and Methods: In children <16 years of age admitted for urinary tract infection (UTI) to the Dr. Sami Ulus Teaching and Training Hospital from January 2004 to December 2008, positive urine cultures were reviewed. Results: A total of 3,485 positive urine cultures were identified, of which 2,379 (68%) were from females and 106 (32%) from males. Their mean age was 63.5 ± 40.7 months. Escherichia coli was the most common causative agent both in total and among different age groups. Ampicillin had the highest resistance rate from all the pathogens isolated (63.8%), followed by piperacillin (51.8%) and trimethoprim-sulfamethoxazole (TMP-SMX; 48.6%). Cephalotin also had a high resistance rate (32.7%). The least resistance was for imipenem, amikacin, netilmicin and ciprofloxacin (0.13, 1.7, 2.4 and 7.5%, respectively). None of the Klebsiella and Pseudomonas isolates were resistant to imipenem. None of the Staphylococcus aureus isolates were resistant to teicoplanin and vancomycin. Vancomycin-resistant Enterococcus spp. were isolated from two cultures. Conclusion:E. coli was the most common causative agent of UTI in children. Ampicillin, TMP-SMX or cephalothin and piperacillin had the highest resistance rates against urinary tract pathogens in our center.

Opportunistic Infections As Aids-Defining Conditions: Case Study Of Hiv Infected Persons In Eastern Nigeria

The prevalence of opportunistic infections as WHO’s AIDS defining illnesses was investigated microbiologically in 2199 HIV positive Nigerians using urine, stool, sputa and nasopharyngeal secretions. ANOVA and the Pearson Chi-Square tests were used for data analysis. Frequently isolated gastrointestinal bacterial pathogens included non-typhoidal Salmonellae species (69.5%), Campylobacter jejuni (64.9%), Shigella species (60.0); diarrhea inducing protozoa: Entamoeba histolytica (62.8%), Gardia. lamblia (61.6%), Cryptosporidium spp (24.1); respiratory tract pathogens: Streptococcus pnuemoniae (84.6%) > H. influenzae (72.8%) > Pseudomonas aeroginosa (27.1%); fungal pathogens: C. albicans (65.6%) > H. duboisii (54.4%) > Aspergillus spp (45.0%) > Pneumocystis carinii (4.6%) > Cryptococcus neoformans (4.2%). Isolated urinary tract pathogens included Bacteriodes fragilis (77.7%), Klebsiella aerogene (69.4%), E. coli (64.8%), Proteus spp (50.5%). The occurrence of each pathogen in the various anatomical sites was statistically significant (F cal = .997; p < 0.005) indicating their possible involvement in disease causation and progression of HIV infection to AIDS.

Antimicrobial susceptibility of some quinolone antibiotics against some urinary tract pathogens in a tertiary hospital, Yola, Adamawa State, Nigeria

Antibiotic resistance is an increasing threat to life and morbidity and mortality. UTIs are greater when caused by drug-resistant microorganisms. A total of 250 urine samples were collected and out of these, some 143 different strains of bacteria which were isolated, showed positive bacterial growth. Among the different uropathogens, 53 (37.1%) were obtained from male subjects, while the remaining 90 (62.9%) were from female subjects. Of the 143 bacterial isolates obtained, gram negative bacteria had the highest frequency of occurrence with 91 (63.6%) than gram positive bacteria with 52 (36.4 %). The organisms isolated were Escherichia coli 37 (25.9%), Staphylococcus aureus (17.5%); Enterococcus faecalis (15.4 %), Klebsiella aerogenes (14.7%), Klebsiella pneumoniae (5.6%), Proteus vulgaris (11.4%) species 8 (10%); Pseudomonas aeruginosa 7 (4.9%), Staphylococcus saprophyticus (4.5 %) and P. Proteus mirabilis 2 (1.4%) in order of ranking. The susceptibility of the isolates to the quinolone antibiotics were assessed using the disc diffusion method. Among the gram-negative bacteria, P. aeruginosa was less susceptible with a profile of (71.4%) to ciprofloxacin, ofloxacin (42.9%), pefloxacin (57.1%), and sparfloxacin (42.9 %), but no activity for nalidixic acid. The susceptibility pattern followed similar trend for the other gram-negative bacteria. Among the gram-positive bacteria, S. aureus was least sensitive with a profile of 64.0% for ciprofloxacin, ofloxacin (56.0%), pefloxacin (52.0%), Sparfloxacin (52.0%) and nalidixic acid (8.0%). The quinolone antibiotics were still effective against the uropathogens, but should be reserved for only complicated UTIs to avoid the development of resistance. Key words: Resistance, morbidity, mortality, susceptible, uropathogens

Crystalline bacterial biofilm formation on urinary catheters by urease-producing urinary tract pathogens: a simple method of control

The problem of catheter encrustation stems from infection by urease-producing bacteria. These organisms generate ammonia from urea, elevate the pH of urine and cause crystals of calcium and magnesium phosphates to form in the urine and the biofilm that develops on the catheter. In this study, a laboratory model was used to compare the ability of 12 urease-positive species of urinary tract pathogens to encrust and block catheters. Proteus mirabilis, Proteus vulgaris and Providencia rettgeri were able to raise the urinary pH above 8.3 and produce catheter-blocking crystalline biofilms within 40 h. Morganella morganii and Staphylococcus aureus elevated the pH of urine to 7.4 and 6.9, respectively, and caused some crystal deposition in the biofilms but did not block catheters in the 96 h experimental period. Isolates of Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Serratia marcescens, Pseudomonas aeruginosa and Providencia stuartii were only capable of raising the pH of urine to a maximum of 6.4 and failed to cause crystal deposition in the biofilm. The most effective way to prevent catheter encrustation was shown to be diluting urine and increasing its citrate concentration. This strategy raises the nucleation pH (pH(n)) at which calcium and magnesium phosphates crystallize from urine. Increasing the fluid intake of a healthy volunteer with citrated drinks resulted in urine with a pH(n) of >8.0 in which catheter encrustation was inhibited. It is suggested that this dietary strategy will be an effective means of controlling catheter encrustation, whichever bacterial species is causing the problem.

Use of chromogenic Agar in detection of urinary tract pathogens and antimicrobial Susceptibility

Use of chromogenic Agar in detection of urinary tract pathogens and antimicrobial Susceptibility

Chronic Prostatitis

The National Institutes of Health (NIH) has redefined prostatitis into four distinct entities. Category I is acute bacterial prostatitis. It is an acute prostatic infection with a uropathogen, often with systemic symptoms of fever, chills and hypotension. The treatment hinges on antimicrobials and drainage of the bladder because the inflamed prostate may block urinary flow. Category II prostatitis is called chronic bacterial prostatitis. It is characterized by recurrent episodes of documented urinary tract infections with the same uropathogen and causes pelvic pain, urinary symptoms and ejaculatory pain. It is diagnosed by means of localization cultures that are 90% accurate in localizing the source of recurrent infections within the lower urinary tract. Asymptomatic inflammatory prostatitis comprises NIH category IV. This entity is, by definition, asymptomatic and is often diagnosed incidentally during the evaluation of infertility or prostate cancer. The clinical significance of category IV prostatitis is unknown and it is often left untreated. Category III prostatitis is called chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). It is characterized by pelvic pain for more than 3 of the previous 6 months, urinary symptoms and painful ejaculation, without documented urinary tract infections from uropathogens. The syndrome can be devastating, affecting 10-15% of the male population, and results in nearly 2 million outpatient visits each year. The aetiology of CP/CPPS is poorly understood, but may be the result of an infectious or inflammatory initiator that results in neurological injury and eventually results in pelvic floor dysfunction in the form of increased pelvic muscle tone. The diagnosis relies on separating this entity from chronic bacterial prostatitis. If there is no history of documented urinary tract infections with a urinary tract pathogen, then cultures should be taken when patients are symptomatic. Prostatic localization cultures, called the Meares-Stamey 4 glass test, would identify the prostate as the source for a urinary tract infection in chronic bacterial prostatitis. If there is no infection, then the patient is likely to have CP/CPPS. For healthcare providers, the focus of therapy is symptomatic relief. The first therapeutic measure is often a 4- to 6-week course of a fluoroquinolone, which provides relief in 50% of men and is more efficacious if prescribed soon after symptoms begin. Second-line pharmacotherapy involves anti-inflammatory agents for pain symptoms and alpha-adrenergic receptor antagonists (alpha-blockers) for urinary symptoms. Potentially more effective is pelvic floor training/biofeedback, but randomized controlled trials are needed to confirm this. Third-line agents include 5alpha-reductase inhibitors, glycosaminoglycans, quercetin, cernilton (CN-009) and saw palmetto. For treatment refractory patients, surgical interventions can be offered. Transurethral microwave therapy to ablate prostatic tissue has shown some promise. The treatment algorithm provided in this review involves a 4- to 6-week course of antibacterials, which may be repeated if the initial course provides relief. Pain and urinary symptoms can be ameliorated with anti-inflammatories and alpha-blockers. If the relief is not significant, then patients should be referred for biofeedback. Minimally invasive surgical options should be reserved for treatment-refractory patients.

The Effect of Lactic Acid Bacteria Isolates on the Urinary Tract Pathogens to Infants In Vitro

Urinary tract infections are common clinical problems in children, even though lots of treatment strategies have been tried. Many studies of the application of probiotics for urinary tract infection in female adults exist, but there is a lack of studies in children. The aims of this study were to screen probiotic strains for inhibiting the uropathogens in vitro, to find candidates for in vivo study. Nine strains of E. coli were isolated from children with urinary tract infection and six uropathogens were obtained from Korean Colletion for Type Cultures and American Type Culture Collection. Also 135 lactic acid bacteria (LAB) strains were isolated from healthy children, and were identified through physiologic, biochemical methods, 16S rDNA PCR, and data analysis. And with agar disk diffusion assay technique the antimicrobial activities of these LAB strains against those uropathogens were examined. Three strains of separated LAB strains demonstrated major antimicrobial activity against all the uropathogens. In the agar disk diffusion assay technique, antimicrobial activities increased most in the 4th day culture broth with separated Lactobacillus. In summary, some LAB can be used as candidates to develop the probiotic microorganisms that inhibit uropathogens in children, and are expected to be applied to treatment and prevention of pediatric urinary tract infection.

Antibacterial activity of medicinal plants against pathogens causing complicated urinary tract infections

Seventeen Indian folklore medicinal plants were investigated to evaluate antibacterial activity of aqueous, ethanol and acetone extracts against 66 multidrug resistant isolates of major urinary tract pathogens (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Enterococcus faecalis) by disc diffusion method. Ethanol extract of Zingiber officinale and Punica granatum showed strong antibacterial activity against Escherichia coli. Ethanol extracts of Terminalia chebula and Ocimum sanctum exhibited antibacterial activity against Klebsiella pneumoniae. Ethanol extract of Cinnamomum cassia showed maximum antibacterial activity against Pseudomonas aeruginosa while ethanol extract of Azadirachta indica and Ocimum sanctum exhibited antibacterial activity against Enterococcus faecalis. The results support the folkloric use of these plants in the treatment of urinary tract infections by the tribals of Mahakoshal region of central India.

Community-acquired urinary tract pathogens and their resistance patterns in hospitalized children in southeastern Ontario between 2002 and 2006

The purpose of the present study was to assess the epidemiology and resistance patterns of bacteria causing urinary tract infections in children who were admitted to Kingston General Hospital (Kingston, Ontario) - the regional tertiary care hospital of southeastern Ontario. A retrospective chart review of patients one to 18 years of age who were admitted to Kingston General Hospital with a discharge diagnosis of urinary tract infection between 2002 and early 2006 was undertaken. One hundred forty-two patient charts were reviewed, of which 56.3% of patients were female. The mean age of the patients was 12.3 months. The most common bacteria identified on urine culture over a five-year period were Escherichia coli (71.6%), Enterococcus species (5.7%) and Klebsiella species (5.0%). Bacteria were frequently resistant to ampicillin (54.4%) and trimethoprim-sulfamethoxazole (TMP-SMX) (40.4%). During the three months before admission, bacteria resistant to ampicillin were cultured from the urine of 75.6% of patients who were receiving some antibiotic, compared with 44% of children with no documented use of antibiotics (P<0.0001). Resistance to TMP-SMX in those with pre-existing genitourinary disease was 72.2% versus 31.8% in those without (P<0.0001). Patients who had previous admissions for urinary tract infections also showed greater resistance to TMP-SMX (70.6% versus 32.7%; P<0.005), cefazolin (64.7% versus 20.0%; P<0.0001) and nitrofurantoin (58.8% versus 18.2%; P<0.0001). There was a high resistance to ampicillin. Risk factors for resistant bacteria included the use of antibiotics three months before admission, previous genitourinary disease and previous admissions for urinary tract infections. In the presence of these risk factors, a third-generation cephalosporin as first-line antimicrobial therapy is recommended. However, the combination of ampicillin plus gentamicin can be considered for empirical therapy in low-risk patients.

Diversity of Urinary Tract Pathogens and Drug Resistant Isolates of &lt;i&gt;Escherichia coli&lt;/i&gt; in different age and gender Groups of Pakistanis

Purpose: This paper was mainly aimed to investigate drug resistance of the various urinary tract infection (UTI) pathogens from patients of different gender and age groups of Pakistanis. Method: For these purposes, urine samples of 109 patients were analyzed. Samples were screened on CLED agar. Antimicrobial susceptibility testing was performed by Kirby Bauer\'s disc diffusion method. Isolated colonies were processed for biochemical characterization and antibiotic sensitivity to ampicillin, amikacin, augmentin, ceftazidime, ceftriaxone, cefuroxime, cotrimoxazole, ciprofloxin, imipenem, meropenem, tazocine, trimethoprim, gentamicin and nitrofuratoin. Result: E.Coli was found to be the most frequent causative agent of UTIs (66%) followed by Enterococci (8.3%), Candida spp. and Pseodomonas spp. (7.3% each), Klebsiella spp. (5.5%) and Enterobacter spp. (2.7%). Proteus. and Morgenella species were found in less than 1% of the cases. E.coli showed variable antimicrobial resistance to different antibiotics as 92%, 86%, 80%, 62%, 47%, 20% and 4% of the isolates were found to be resistant to ampicillin, cotrimoxazole, ciprofloxin, gentamicin, nitrofuratoin and amikacin, respectively. Conclusion: The most effective in vitro agents were found to be amikacin followed by gentamicin (among the parenterals), and ciprofloxin among the orally administratered ones. A higher prevalence of UTIs was observed in the female population and E.coli showed no resistance to nitrofuratoin in age groups of 50+ and 70+ in both genders. Keywords: Urinary tract infections, Age, Gender, Resistant microbes, E.coli. Tropical Journal of Pharmaceutical Research Vol. 7 (3) 2008: pp. 1025-1031

Effect of triclosan on the formation of crystalline biofilms by mixed communities of urinary tract pathogens on urinary catheters

The crystalline bacterial biofilms that encrust Foley catheters compromise the care of many elderly and disabled patients. The aim of this study was to examine whether the biocide triclosan can prevent encrustation by the mixed flora of uropathogens that commonly infect patients undergoing long-term catheterization. Models of the catheterized bladder were inoculated with communities of organisms isolated from patients who were experiencing catheter blockage. The catheter retention balloons were inflated with water or triclosan (3 g triclosan l(-1) in 0.1 M sodium carbonate) and urine was supplied to the models for up to 7 days. The effect of triclosan was recorded on the viable cell populations, the pH of the residual urine and the times that catheters took to block. The extent of encrustation of the catheters was visualized by scanning electron microscopy. In models inoculated with communities containing Proteus mirabilis, triclosan prevented the rise in urinary pH that drives crystalline biofilm formation and catheter blockage. The biocide had no effect on populations of Enterococcus faecalis and Pseudomonas aeruginosa, but Proteus mirabilis, Escherichia coli and Klebsiella pneumoniae were eliminated from the residual urine and the catheters drained freely for the 7-day experimental period. In models inoculated with a mixed community containing Providencia rettgeri, catheters inflated with triclosan continued to block rapidly. Although K. pneumoniae and Proteus vulgaris were eliminated from the residual urine, there was no effect on the viability of Providencia rettgeri. The results indicate that the triclosan strategy should be limited to the treatment of patients who are infected with Proteus mirabilis.

Antimicrobial resistance patterns of urinary tract pathogens and rationale for empirical therapy in Turkish children for the years 2000–2006

In patients with suspected urinary tract infection (UTI), antibiotic treatment is usually started empirically, before urine culture results are available. Unfortunately, antibiotic resistance has become an increasingly pressing clinical issue in many countries. The objective of this study was to assess the changing susceptibility of urinary pathogens to commonly used antimicrobials in a six-year period to evaluate the options for empirical antibiotic therapy in children with community acquired UTI. A retrospective analysis of data from all pediatric urine samples processed at Fatih University Medical School microbiology laboratory was undertaken for a period of six years (January 2000-December 2006). A total of 767 urinary pathogens were isolated from 767 episodes of UTI in 698 patients. The most common causative agent was Escherichia coli (E. coli) followed by Klebsiella spp. and others. In 2000 almost 60% of the E. coli isolates were susceptible to ampicillin (AMP), more than 40% to Co-trimoxazole (SXT), more than 80% to gentamicin (GN), more than 90% to cefuroxime (CXM) and amikacin (AN), and more than 60% to piperacillin (PIP). By 2006 more than 70% were resistant to AMP and more than 50% were resistant to PIP. In 2000 CIP (2.7% resistant isolates) and CXM (3.4% resistant isolates) were the most active agents against Klebsiella spp.; and none of the isolates was found to be resistant to imipenem (IMP). In 2006 GN (2.7% resistant isolates), CIP (3.5% resistant isolates), CXM (2.7% resistant isolates), and AN (8.9% resistant isolates) were the most active agents against these species and still no resistance to IMP was found. For E. Coli the increase in resistance to AMP, CTX, IMP, and PIP was statistically significant (P < 0.05). For Klebsiella spp. the increase in resistance to AMP and CXM was statistically significant (P < 0.05). Empirical antibiotic selection should be based on knowledge of the local prevalence of bacterial organisms and antibiotic sensitivities, because resistance patterns may vary in different regions.

Optimal Probe Length and Target Location for Electrochemical Detection of Selected Uropathogens at Ambient Temperature

We have previously demonstrated the clinical validity of the rapid detection of uropathogens by use of a DNA biosensor. This assay involves the hybridization of capture and detector probe pairs with bacterial 16S rRNA target molecules to form a DNA-RNA sandwich on the sensor surface. Horseradish peroxidase-conjugated antibody binds to the detector probe to enzymatically amplify the hybridization signal. These previous studies involved the hybridization of bacterial 16S rRNA target sequences with 35-mer oligonucleotide probe pairs at 65 degrees C. Achievement of point-of-care technology will be greatly facilitated by ambient-temperature detection. The purpose of this study was to examine the effects of probe length and target location on signal intensity using hybridization temperatures of 20 to 25 degrees C. Signal intensity was found to vary dramatically with hybridization location in the species-specific bulge region of 16S rRNA helix 18. Probe pairs of as short as 10 nucleotides in length were able to produce a significant electrochemical signal, and signal intensity was correlated with probe length for probes of 10 to 20 nucleotides in length. The sensitivity of the Escherichia coli-specific 15-mer probe pairs was approximately 330 cells. These shorter probes allowed differentiation of Klebsiella pneumoniae from Proteus mirabilis 16S rRNA target sequences differing by a single nucleotide. A panel of oligonucleotide probe pairs ranging from 11 to 23 nucleotides in length was able to distinguish among seven groups of urinary tract pathogens. In conclusion, we have developed short oligonucleotide probe pairs for the species-specific identification of uropathogens at ambient temperature by use of an electrochemical sensor.

Antibacterial activity of &lt;i&gt; Barringtonia acutangula&lt;/i&gt; against selected urinary tract pathogens

Barringtonia acutangula (L.) Gaertn belonging to family Barringtoniaceae was investigated to evaluate In vitro antibacterial activity of aqueous, ethanolic, petroleum ether and chloroform extracts against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus faecalis and Escherichia coli the major urinary tract infection causing pathogens were tested by disc diffusion assay method and the minimum inhibitory concentration was evaluated. Ethanol (95%) extract exhibited broader spectrum of inhibition followed by chloroform, petroleum ether and aqueous extracts against the urinary tract pathogens under test. An attempt has been made to compare the activity of extracts with standard antibiotics against selected urinary tract infection causing pathogens.

Systemic multicompartmental effects of the gut microbiome on mouse metabolic phenotypes

To characterize the impact of gut microbiota on host metabolism, we investigated the multicompartmental metabolic profiles of a conventional mouse strain (C3H/HeJ) (n=5) and its germ-free (GF) equivalent (n=5). We confirm that the microbiome strongly impacts on the metabolism of bile acids through the enterohepatic cycle and gut metabolism (higher levels of phosphocholine and glycine in GF liver and marked higher levels of bile acids in three gut compartments). Furthermore we demonstrate that (1) well-defined metabolic differences exist in all examined compartments between the metabotypes of GF and conventional mice: bacterial co-metabolic products such as hippurate (urine) and 5-aminovalerate (colon epithelium) were found at reduced concentrations, whereas raffinose was only detected in GF colonic profiles. (2) The microbiome also influences kidney homeostasis with elevated levels of key cell volume regulators (betaine, choline, myo-inositol and so on) observed in GF kidneys. (3) Gut microbiota modulate metabotype expression at both local (gut) and global (biofluids, kidney, liver) system levels and hence influence the responses to a variety of dietary modulation and drug exposures relevant to personalized health-care investigations.

Distribution and Resistance Trends of Community Associated Urinary Tract Pathogens in Sharjah, UAE

Objective To describe the spectrum of etiologic agents causing community associated UTI and their antimicrobial resistance trends in a large teaching hospital in Sharjah, United Arab Emirates. Methods A retrospective review of the microbiology laboratory records of four hundred ninety two cases of community associated UTI between April 2006 and March 2007 was carried out. Etiologic agents and their antimicrobial susceptibility pattern were analyzed. Results A wide spectrum of uropathogens was isolated of which the leading etiologic agents of community associated UTI were Escherichia coli (207 strains) and Klebsiella species (90 strains). Sixty-six per cent of Gram-negative bacilli were resistant to amoxicillin, 58.5% were resistant to trimethoprim-sulfamethoxazole and more than 50% were resistant to cephalexin. However, resistance rate to antimicrobials like ciprofloxacin and ceftriaxone remain relatively low 9.7% and 7.6% respectively. Conclusions Escherichia coli remains the leading cause of community associated UTI. In-vitro antimicrobial resistance pattern of the isolates revealed that trimethoprim-sulfamethoxazole, cephalexin and amoxycillin the commonly used first-line antimicrobials were becoming less and less effective in their treatment. This information can help in changing preferences of suitable antimicrobial agent in treatment of community associated UTI.

Species interactions in mixed-community crystalline biofilms on urinary catheters

Previous experimental investigations of the crystalline biofilms that colonize and block urinary catheters have focussed on their formation by pure cultures of Proteus mirabilis. In the urine of patients undergoing long-term catheterization, P. mirabilis is commonly found in mixed communities with other urinary tract pathogens. Little is known about the effect that the other species have on the rate at which P. mirabilis encrusts catheters. In the present study, a set of data on the nature of the bacterial communities on 106 catheter biofilms has been analysed and it was found that while species such as Providencia stuartii and Klebsiella pneumoniae were commonly associated with P. mirabilis, when Escherichia coli, Morganella morganii or Enterobacter cloacae were present, P. mirabilis was rarely or never found. The hypothesis that the absence of P. mirabilis from some biofilm communities could be due to its active exclusion by other species has also been examined. Experiments in laboratory models showed that co-infection of P. mirabilis with M. morganii, K. pneumoniae or E. coli had no effect on the ability of P. mirabilis to encrust and block catheters. Co-infection with Ent. cloacae or Pseudomonas aeruginosa, however, significantly increased the time that catheters took to block (P <0.05). The growth of Ent. cloacae, M. morganii, K. pneumoniae or E. coli in the model for 72 h prior to superinfection with P. mirabilis significantly delayed catheter blockage. In the case of Ent. cloacae, for example, the mean time to blockage was extended from 28.7 h to 60.7 h (P < or =0.01). In all cases, however, P. mirabilis was able to generate alkaline urine, colonize the biofilms, induce crystal formation and block the catheters. The results suggest that although there is a degree of antagonism between P. mirabilis and some of the other urinary tract organisms, the effects are temporary and whatever the pre-existing urinary microbiota, infection with P. mirabilis is thus likely to lead to catheter encrustation and blockage.

In Vitro Susceptibility of Community-Acquired Urinary Tract Pathogens to Commonly Used Antimicrobial Agents in Spain: a Comparative Multicenter Study (2002-2004)

The susceptibility patterns of 2724 uropathogens isolated in 9 Spanish regions during 2002, and 3013 obtained in 2004 were determined. The antibiotics tested were fosfomycin trometamol, amoxicillin, co-amoxiclav, cefixime, cefuroxime-axetil pipemidic acid, ciprofloxacin, trimethoprim plus sulphamethoxazole and nitrofurantoin.Escherichia coli was the main pathogen in both studies (73% vs. 68.3%) followed by Proteus mirabilis (7.2% vs. 6.4%) and Klebsiella pneumoniae (5.4% vs. 5.2%). Enterococcus spp. (4.7% vs. 6.8%)Streptococcus agalactiae (1.7% vs.3.1%) and Staphylococcus saprophyticus (0.7% vs. 1.3%) were the most frequent Gram-positive pathogens. 31.3% of E. coli in 2002 and 32% in 2004 were susceptible to all antibiotics tested. Around 40% of E. coli were resistant to a single agent. 21.6-24.1% were resistant to two antibiotics. 35.4% of first period isolates, and 37.6% of second period ones were resistant to two or more classes of antibiotics. Fosfomycin (2.1- 2.8%) and nitrofurantoin (3.5-5.7%) had the lowest resistance rates for E. coli. Amoxicillin (58.2-58.7%), co-trimoxazole (30.8-33.8%) and ciprofloxacin (22.6-22.7%) showed the highest resistance rates, and their suitability as empiric treatments for UTI should probably be re-evaluated.