Agent Of Urinary Tract Infections Research Articles

Corynebacterium coyleae as potential urinary tract pathogen

Corynebacterium coyleae is part of the commensal microflora of the skin, urethra, mucous membranes, and genital tract. Isolates from patients with urinary tract infection (UTI) were reported, but the pathogenic potential of this species has not been defined yet. The aim of the study is to determine whether C. coyleae could be the etiological agent of UTI and to analyze its antibiotic susceptibility. Urine samples were cultured quantitatively according to accepted laboratory procedures. The identification of bacterial isolates was carried out using the Vitek MS (bioMérieux) and antibiotic susceptibility was tested using disc diffusion according to EUCAST guidelines. Between 1 January 2017 and 30 October 2018, a total of 39 C. coyleae strains were isolated. This represented 0.32% of all urine samples cultured in the laboratory during the collection period. The strains were isolated from samples obtained from 35 women and 3 men (age median for all—64 years). One female patient presented with C. coyleae in her urine twice at an interval of 21 months. In six cases of UTI, C. coyleae was isolated in monoculture. The isolates had the same resistance pattern. A total of 11 strains were obtained from cases with a clinical diagnosis of UTI. In 13 cases, the strain was cultured in a monoculture and in 28 cases with accompanying species. All strains were susceptible to vancomycin. However, resistance to ciprofloxacin was observed for 58.4% of the strains. Urine isolates of C. coyleae must be considered as contamination or normal flora in most cases (28/39, 72%). In the remaining cases, it can be considered as potential etiologic agents, mostly in women and especially in the 6 UTI cases where C. coyleae was found as the single culture-positive species. Several of these isolates demonstrate resistance to antibiotics commonly used in empiric treatment of urinary tract infections.

Antibiotics susceptibility patterns of Citrobacter freundii isolated from pa-tients with urinary tract infection in Al-Najaf governorate – Iraq

Citrobacter freundii is one of the most causative agents of urinary tract infection in human due to their high antimicrobials resistance. Therefore, this study aimed to evaluate the ability of Citrobacter freundii to resist to fifteen antimicrobials. A total of 461 urine samples were collected from patients infected with urinary tract infection, females and males, age groups between 18 to 60 years old performed in Al-Najaf central hospital in Al-Najaf City, Iraq, during April to December 2018. Antimicrobials susceptibility testing was performed by disc diffusion method according to the Kirby-Bauer method onto Mueller Hinton agar surface. There were 30 isolates (6.5%) diagnosed as Citrobacter freundii. Antimicrobial resistance rate of the 30 isolates to Amoxicillin and Chloramphenicol were all high (25 isolates 83.4%), Ciprofloxacin, Streptomycin and Sulfonamide (24 isolates 80%). The good resistance rate was observed for Penicillin, Amoxiclav and Ceftazidime (21 isolates 70%). The moderate resistance rate was observed for Cefotaxime (19 isolates 63.3%), Ceftriaxone (20 isolates 66.7%), Gentamicin (15 isolates 50%), Tobramycin (18 isolates 60%) and Erythromycin (20 isolates 66.7%). The lowest resistance rate was observed for Tetracycline (19 isolates 63.3%). While Imipenem provided full antibacterial activity (30 isolates 100%). Of the total 30 isolates, 22 (73.3%) were multi-drug resistance, 8(26.7%) extensive-drug resistance and no isolates were pan-drug resistance. While 19 isolates (63.3%) were extended-spectrum beta-lactamase producing Citrobacter freundii. Citrobacter freundii has highly resistant against most antimicrobials and became more dangerous bacteria cause urinary tract infection.

Distribution of Virulence and Antimicrobial Resistance Genes in Phylogenetic Groups of Escherichia coli Strains Isolated from Mexican Patients with Urinary Infection

Background: The causative primary agent of urinary tract infections (UTI) is uropathogenic Escherichia coli (UPEC); however, commensal Escherichia coli (CEC) has been also implicated in the development of UTI. Due to the recent emergence of virulent and resistant strains, it is necessary to have evidence to demonstrate that UPEC and CEC are isolated from patients with UTI and subsequently they have the genes to be considered pathogenic. Objectives: To determine the distribution of resistance and virulence genes in UPEC and CEC strains isolated from the patients with UTI (hospitalized and ambulatory). Methods: One hundred seven E. coli strains were genotyped according to Clermont protocol and were subjected to PCR assays in order to detect resistance and virulence genes. In addition, the antimicrobial test in solid media was performed to determinate the correlation “pheno/genotype”. Results: Genotyping analysis showed that group B2 (42.05%) was the most predominant, strains followed by A (27.1%), D (24.29%), and finally, B1 (6.54%). β-lactams, carbapenems, aminoglycosides, and nitrofurans showed the best activity. The virulence gene frequencies were: fimH (92/85.98%), iutA (68/63.55%), traT (66/61.68%), papC (36/33.64%), and cnf1 (15/14.02%) while resistance genes were: blaCTX-M(41/38.32%), blaOXA (49/45.79%), and blaSHV (2/1.87%). The associations fimH/blaCTX, fimH/blaOXA, traT/blaCTX, traT/blaOXA, iutA/blaCTX, and iutA/blaOXA showed higher incidence while the associations with cnf1 and papC genes were low. Conclusions: Uropathogenic E. coli has the necessary genetic elements (virulence and resistance) to be considered the main pathogen causing UTI in the Mexican population. Additionally, to our knowledge, there are no studies in our country demonstrating that the CEC isolated from the patients with UTI contains genetic elements of virulence and resistance that allow them to be potentially pathogenic.

Photodynamic enhancement of the activity of antibiotics used in urinary tract infections

Photodynamic therapy (PDT) has been proven to kill different microbial cells. However, to our knowledge, none of the available reports describes the modulatory effect of this therapy on the antibacterial activity of antibiotics against Escherichia coli rods being the main causative agent of urinary tract infections (UTIs). Therefore, the aim of our study was to verify if the PDT can enhance the antibacterial activity of antibiotics recommended in the treatment of UTIs. An attempt to determine the optimal conditions of PDT to enhance the bactericidal activity of ciprofloxacin, amikacin, and colistin has been made. In order to find the optimal antimicrobial conditions, the efficacy of four protocols associated with the use of different energy doses (70 and 120 J/cm2) and chlorin e6 (Ce6) concentrations (50 and 100 μg/mL) has been verified. The antibacterial effect of combined PDT and antibiotics was assessed by the time-kill assay. The best results were achieved for Ce6 at a concentration of 100 μg/mL and the energy dose 120 J/cm2 for bacterial suspensions treated with ciprofloxacin. Taken together, our results showed that PDT using Ce6 improves the antibacterial activity of antibiotics effectively inhibiting bacterial growth and being promising in the elimination of bacterial UTIs in humans.

Canine Cystitis Caused by Salmonella enterica subsp. enterica

Background: Urinary tract infection in dogs is usually associated with the presence of bacteria, with a higher prevalence of Gram-negative bacteria, represented mainly by enteric bacteria such as Escherichia coli and Proteus spp., followed by Gram-positive bacteria such as Staphylococcus spp., and Streptococcus spp. There are scant reports of Salmonella spp. as the causative agent of urinary tract infection in dogs. Indeed, the literature describes only a few cases, most of which involve the isolation of these bacteria in feces. This paper reports a case of canine cystitis caused by Salmonella enterica subsp. enterica in the northeast region of Brazil.Case: A female dog of the Fila Brasileiro breed, about 9 year-old, wormed but unvaccinated, was evaluated at the Veterinary Hospital of the Federal University of Pernambuco – UFRPE. The dog showed clinical signs of apathy, cachexia, polyphagia, polyuria and opacity of the crystalline lens. The dog’s owner stated that the animal was fed with commercial dog food. In the clinical exam, the patient presented pale mucosa, cachexia, absence of ectoparasites, and her rectal temperature was 39.5°C. Moreover, cardiorespiratory auscultation of the patient revealed tachycardia (190 bpm) and tachypnea (36 bpm). The owner’s main complaint was the clinical condition of frequent urination (polyuria). A urinalysis and urine culture with antibiogram were requested as complementary exams, after collecting the urine by cystocentesis. The volume obtained in the physical examination of urinalysis was 7 mL of yellow urine with a putrid smell, cloudy appearance and density of 1.024. The chemical examination revealed pH 6.5, protein (+++), bilirubin (+), normal urobilinogen and negative reactions for glycoses, ketone, nitrite and urine occult blood. Bacteriuria and pyuria were detected in a urine sediment test. Urine was cultured on blood agar and Levine agar in a bacteriological incubator at 37°C under aerobiosis, for 24 h. This culture produced an exuberant and pure growth of glossy grey bacterial colonies on blood agar and glossy colonies on Levine agar. The Gram test revealed gram-negative bacilli. The sample was subjected to biochemical tests to identify Gram-negative enterobacteria, whose results provided a presumptive identification of Salmonella species. The microbial species was identified using a VITEK 2 Compact®, and was followed by a serology test for the identification of the serogroup using a polyvalent serum, which enabled the identification of Salmonella enterica subsp. enterica. The antibiogram showed sensitivity to ciprofloxacin, gentamicin and penicillin, and resistance to amoxicillin and ampicillin.Discussion: Clinical signs of cachexia and polyuria may be related to canine urinary tract infection caused by Salmonella enterica subsp. enterica, since these symptoms had already been recorded previously in a case of a bacterial infection by the same serogroup. Isolation of Salmonella spp. in a non-selective medium was determinant in identifying these bacteria. Since these are not commensal bacteria of the canine urinary tract, their isolation in this tract indicates that they are responsible for the infection or disease, although such cases are rare. Another aspect that should be highlighted is the risk of human infection, because of the zoonotic potential of Salmonella spp., which may be transmitted by contact with dog urine. This is the first report of the isolation of Salmonella enterica subsp. enterica in a case of canine cystitis on the northeast region of Brazil, and underscores the importance of complementary diagnostic exams such as urine culture.

Dietary restriction of iron availability attenuates UPEC pathogenesis in a mouse model of urinary tract infection.

Iron is a critical nutrient required by hosts and pathogens. Uropathogenic Escherichia coli (UPEC), the principal causative agent of urinary tract infections (UTIs), chelate iron for their survival and persistence. Here, we demonstrate that dietary modulation of iron availability limits UPEC burden in a mouse model of UTI. Mice on a low-iron diet exhibit reduced systemic and bladder mucosal iron availability and harbor significantly lower bacterial burden, concomitant with dampened inflammation. Hepcidin is a master regulator of iron that controls iron-dependent UPEC intracellular growth. Hepcidin-deficient mice ( Hamp1-/-) exhibit accumulation of iron deposits, persistent bacterial burden in the bladder, and a heightened inflammatory response to UTI. However, a low-iron dietary regimen reversed the iron overload and increased bacterial burden phenotypes in Hamp1-/- mice. Thus modulation of iron levels via diet can reduce UPEC infection and persistence, which may have significant implications for clinical management of UTI.

Anti-microbial Resistance Pattern of Uropathogens Isolated from Hospitalized Patients in Imam Khomeini hospital, Tehran, Iran

Background: Urinary tract infection (UTI) is one of the most common type of bacterial infectious diseases which occurs in all age groups. The aim of this study was to determine anti-microbial resistance pattern of bacterial pathogens causing UTIs in hospitalized patients at the Imam Khomeini Hospital, Tehran, Iran. Material and Methods: Urine samples were collected from 11157 hospitalized patients at different wards of Imam Khomeini Hospital in Tehran, between January 2015 and December 2015.The cultured plates were assessed for significant bacterial growth. Anti-microbial susceptibility test was performed using standard disk diffusion method. Results: Out of the 11157 collected urine samples, significant bacterial growth of 25.38% was observed. The most common cause of UTI was gram-negative bacteria (82.2%). More than 50% of the gram-negative bacteria were resistant to ceftriaxone, ceftazidime and trimethoprim-sulfamethoxazole. Enterococcus spp. (10.1%) was found as the third causative agent of UTIs and the most common gram-positive bacteria. Conclusion: we conclude that the examination of the most common etiological agent of UTIs and their antimicrobial resistance patterns is advantageous and necessary in order to design a guideline for empirical therapy.

Extracted chitosan disrupts quorum sensing mediated virulence factors in Urinary tract infection causing pathogens.

Quorum sensing (QS) plays an important role during the aetiology of urinary tract infection (UTI), as several virulence factors are under the regulation of QS. Pseudomonas aeruginosa and Serratia marcescens, the primary causative agents of UTI, employ acyl homoserine lactone (AHL) as signal molecules to coordinate various virulence factors. In this present study, chitosan extracted from the marine crab Portunus sanguinolentus was screened for its ability to inhibit the QS-signaling molecules of P. aeruginosa (PA01) and few clinical isolates of P. aeruginosa and S. marcescens. The extracted chitosan on comparison with a commercial chitosan showed significant inhibition of several QS-dependent virulence factors in P. aeruginosa and S. marscenes. Furthermore, qPCR analysis was carried out to confirm the down-regulation of fimA, fimC and flhD genes involved in adhesion and pathogenesis of S. marcescens and lasI and rhlI genes that governs the P. aeruginosa quorum sensing system. Moreover, the chitosan when coated on a catheter was also able to disrupt the mature biofilms which was revealed by scanning electron microscopy. Collectively, the present study showcases the QS inhibitory property of extracted chitosan from crab shells which is being discarded as a recalcitrant biowaste.

In vitro Effects of Antimicrobial Agents on Planktonic and Biofilm Forms of Staphylococcus saprophyticus Isolated From Patients With Urinary Tract Infections.

Bacterial biofilms play an important role in urinary tract infections (UTIs), being responsible for persistent infections that lead to recurrences and relapses. Staphylococcus saprophyticus is one of the main etiological agents of UTIs, however, little is known about biofilm production in this species and especially about its response to the antimicrobial agents used to treat UTIs when a biofilm is present. For this reason, the aim of this work was to evaluate the response of S. saprophyticus biofilms to five antimicrobial agents. Staphylococcus saprophyticus was evaluated for antimicrobial susceptibility in its planktonic form by means of minimum inhibitory concentration (MIC) and in biofilms by means of minimum inhibitory concentration in biofilm (MICB) against the following antimicrobial agents by the microdilution technique: vancomycin, oxacillin, trimethoprim/sulfamethoxazole, ciprofloxacin, and norfloxacin. Of the 169 S. saprophyticus studied, 119 produced a biofilm as demonstrated by the polystyrene plate adherence method. Biofilm cells of S. saprophyticus exhibited a considerable increase in MICB when compared to the planktonic forms, with an increase of more than 32 times in the MICB of some drugs. Some isolates switched from the category of susceptible in the planktonic condition to resistant in the biofilm state. Statistical analysis of the results showed a significant increase in MICB (p < 0.0001) for all five drugs tested in the biofilm state compared to the planktonic form. Regarding determination of the minimum bactericidal concentration in biofilm (MBCB), there were isolates for which the minimum bactericidal concentration of all drugs was equal to or higher than the highest concentration tested.

Epidemiology of candiduria and Candida urinary tract infections in inpatients and outpatients: results from a 10-year retrospective survey

IntroductionThe presence of Candida species in urine (candiduria) is a common clinical finding, which may frequently represent colonization or contamination of specimens, however, they may be etiological agents in urinary tract infections (UTIs) or be indicators of underlying pathology in the genitourinary system or disseminated candidaemia. C. albicans is the most frequently isolated species of the genus, however, an increase in the occurrence of non-albicans Candida species (NACS) has been reported, which may be attributable to frequent exposure to fluconazole.Material and methodsThe aim of this study was to retrospectively assess and compare the prevalence of candiduria and UTIs caused by Candida spp. among inpatients and outpatients at a major clinical center in Hungary, during a 10-year period (2008–2017).ResultsCandiduria was detected in 0.11–0.75% of positive samples from outpatients, while this number was significantly higher for inpatients, ranging between 3.49–10.63% (p <0.001). Overall, C. albicans was the most frequently isolated species (65.22% in outpatients and 59.64% in inpatients), however, the presence of C. glabrata as a relevant etiologic agent (~20–30%) is also noteworthy, because there are corresponding therapeutic consequences.ConclusionsA pronounced female dominance (1.7–2.15-fold), advanced age (~70 years) and hospitalization of affected patients during candiduria is in line with the findings in literature.

Causative agents of urinary tract infections and their antimicrobial susceptibility patterns at a referral center in Western India: An audit to help clinicians prevent antibiotic misuse.

Background:Urinary tract infections (UTIs) remain one of the most common infections in community and susceptibility of uropathogens to commonly used antimicrobials has declined over years. It is important to periodically study susceptibility patterns of uropathogens, so that empiric treatment can be determined using recent data, helping improve patient outcomes.Methods:Urine samples received by the laboratory for culture and susceptibility testing over a period of 3 months were analyzed and included in this study. Antimicrobial susceptibility testing was done on cultured isolates.Results:Of total 3,151 urine samples received, 3,066 were processed, and organisms were isolated from 1,401 (45.69%) samples. Isolation rate from male and female urine samples was 45.29% and 46.32%, respectively. The most commonly isolated organism was Escherichia coli (36.11%), followed by Candida spp. (18.56%), and Klebsiella spp. (18.06%). E. coli was most susceptible to meropenem (91.89%) and imipenem (91.69%). Klebsiella spp. was most susceptible to imipenem(75.89%) and meropenem(75.49%). Susceptibility of E. coli and Klebsiella spp. to nitrofurantoin, cotrimoxazole, and ciprofloxacin was 72.33%, 32.02%, and 18.97%, and 51.77%, 27.27%, and 22.13%, respectively. Candida spp. was most susceptible to amphotericin B (97.30%).Conclusion:Treatment for UTIs should be determined based on current local antimicrobial susceptibility patterns of uropathogens to minimise therapeutic failures and prevent antibiotic misuse.

Appropriate use of antimicrobial agents in urinary tract infections: Perception of physicians and resident doctors

Appropriate and rational use of antibiotics in common infection syndrome such as urinary tract infection (UTI) is the need of the day to prevent bacterial resistance and side effects. Various protocols and guidelines are available for its use; however, perception as well as practices of clinicians may play an important role in their implementations. Methodology: To find problems as well as dilemma in regard to “when,” “what,” and “how long” to use antibiotics in UTI, a questionnaire and opinion-based study was conducted. Sixty clinicians engaged in adult internal medicine practice in Gujarat participated in the study. Many of the participants were resident doctors engaged in serving patients in the outpatient department, teaching hospitals, and medical intensive care units. Results: UTI was the second most common condition where the use of antibiotics is warranted in their practice. All of them had dilemma in the use of antibiotics because of various reasons. Majority did not ask for urine culture examination before giving antibiotics in uncomplicated UTI, but they demanded it in cases of recurrent UTIs, hospitalized patients, and pregnant patients. Their practice was akin to guidelines as far as treatment for asymptomatic bacteriuria was concerned. Fluoroquinolones and beta-lactam antibiotics were the choice of antibiotics in uncomplicated UTIs when urine culture was not ordered and was satisfied with clinical cure. Beta-lactam antibiotics were the choice in pregnant women having UTIs. Fifty-six percent responses favored 5–7-day treatment, whereas 17.86% favored 3-day treatment with fluoroquinolones or beta-lactam antibiotics. Although they were conscious and vigilant about antibiotic resistance problems, limitations did exit in their management plan which bothered them. Conclusions: Gaining insight from perceptions, knowledge, and practices of clinicians regarding the use of antibiotics in common situations such as UTI may be necessary to formulate a plan for local protocol and strategy. Antibiotic stewardship is an essential step. Shortening duration of antibiotics and use of appropriate antibiotics in different clinical situations of UTI may help to prevent antibiotic resistance. This topic needs priority in medical and paramedical education curriculum.

Study of Culture and Sensitivity Pattern In Urinary Tract Infections in A Tertiary Care Center in Nepal

The main purpose of this study was to find out the causative agents of urinary tract infections (UTI) and their culture and antibiotic sensitivity in patients visiting Tribhuvan University and Teaching Hospital (TUTH). A retrospective study conducted among 155 patients, aged from 25-50 years with culture-positive UTI, who visited TUTH from 1st April 2017 to 30th September 2017. A culture of midstream urine was done to find out causative agents and their antibiotic sensitivity performed. Data were evaluated using Microsoft Excel 2016. Female were more affected than males. Escherichia coli (E. coli) was the most common microbes causing UTI in 53% patients. Most of the isolates on culture were Multi-Drug Resistant (MDR) strains to comprise 52%. Of the total gram-negative organisms, 33.9% were Extended Spectrum β-lactamase (ESBL) producers, and 3.57% were Metallo β-lactamase (MBL) producers. 29.41% of Staphylococcus were resistant to methicillin. E.coli is the most common organism causing UTI among adults. Multidrug-resistant has appeared alarming with resistant to most of the first line antibiotics.

Novel Antibiotics in the Treatment of Urinary Tract Infections

Several new antibiotic agents for urinary tract infections include β-lactam/β-lactamase inhibitor combinations with cephalosporins and carbapenems. Siderophore cephalosporins, novel aminoglycosides, fluoroquinolones, and tetracyclines are also in clinical development. Nevertheless, antimicrobial stewardship remains important in preserving the utility of the antibiotic agents currently available.

Risk analysis of antimicrobial resistance in outpatient urinary tract infections of young healthy adults.

Most studies addressing community-acquired urinary tract infections (UTIs) pertain to mixed cohorts, in which young healthy adults are under-represented. We aimed to dissect the intricate interrelation between exposures and subsequent antimicrobial resistance (AMR) patterns in a unique setting of young healthy adults, allowing further guidance in this group. We carried out a retrospective cross-sectional study of all Enterobacteriaceae-associated outpatient UTIs during 2014-16 in soldiers, representing the young fit population in Israel. Electronic medical records were reviewed for demographic and clinical data, antimicrobial exposures and prescriptions. Risk factors for AMR were analysed by multivariate logistic regression. Of 1207 cases, 1144 (94.8%) were females, with a median age of 20.2 years. Escherichia coli was the predominant species (83.2%). Only 686 (56.8%) isolates were fully susceptible. AMR rates were as follows: trimethoprim/sulfamethoxazole, 19.6%; oral cephalosporins, 9.7%-16.7%; amoxicillin/clavulanate, 12.1%; ciprofloxacin, 11.1%; and nitrofurantoin, 12.6%. Predictors of AMR were recurrent UTIs, past-year hospitalization, male gender and non E. coli strains. Antimicrobials prescribed >6 months preceding the culprit infection were not related to AMR. Fluoroquinolone and cephalosporin exposures were highly predictive of further AMR, yet nitrofurantoin and, to a lesser extent, amoxicillin/clavulanate had fewer associations with AMR induction and resistance to these antimicrobials was less associated with any exposure. This nationwide study of community-related UTIs shows significant AMR rates for commonly used oral antimicrobials even in young fit adults. Nitrofurantoin proved once more to be an adequate empirical choice regardless of previous exposures, having a less detrimental effect on future AMR. Conversely, both resistance to fluoroquinolones following previous exposures and the associated heavy ecological burden should deter their common use as first-line agents for UTIs.

PUK15 - PHARMACOECONOMICS MODES OF ANTIBIOTIC THERAPYOF UNCOMPLICATED COMMUNITY-ACQUIRED ACUTE PYELONEPHRITIS IN A MULTIDISCIPLINARY HOSPITALS

Despite the high level of resistance of E. Coli as the main causative agent of urinary tract infections, fluoroquinolones are among the most frequently used antimicrobial agents in empirical therapy of uroinfections. The aim was clinical and economic evaluation of the effectiveness of different antibacterial strategies of community-acquired uncomplicated acute pyelonephritis treatment with the predicted dynamics of resistance of E. coli as the main causative agent of uroinfections. The calculations take into account the literature data on the effectiveness and safety of the starting regime of antibacterial therapy of uncomplicated pyelonephritis with cephalosporins of the 3rd generation, fluoroquinolones, aminoglycosides and carbapenems in terms of hospital specialized medical care. The decision tree model was used. A list of direct and indirect costs was compiled, on the basis of which the cost of 1 case of acute uncomplicated pyelonephritis therapy for each strategy of antibacterial therapy was calculated. The "cost-effectiveness analysis” and budget impact analysis were performed. The cost of 1 case of therapy with acute uncomplicated pyelonephritis gentamicin was the lowest in comparison with alternative strategies (33679,89 rubles). Cost-effectiveness analysis showed that the strategy of antibacterial therapy of acute uncomplicated pyelonephritis with gentamicin dominated alternative strategies: at lower costs, it was also more effective. The budget impact analysis showed that based on the estimated number of cases of acute uncomplicated pyelonephritis in the Russian Federation, replacing the existing practice of antibacterial therapy of acute pyelonephritis will save up to 48715043,21 rubles, which will further treat up to 5537 patients. For a more accurate calculation of clinical and economic efficiency of antimicrobial agents it is necessary to monitor the dynamics of the resistance level in the territory of the Russian Federation.

Streptococcus pneumoniae as an agent of urinary tract infection

Streptococcus pneumoniae as an agent of urinary tract infection

Phosphoethanolamine cellulose enhances curli-mediated adhesion of uropathogenic Escherichia coli to bladder epithelial cells

Uropathogenic Escherichia coli (UPEC) are the major causative agents of urinary tract infections, employing numerous molecular strategies to contribute to adhesion, colonization, and persistence in the bladder niche. Identifying strategies to prevent adhesion and colonization is a promising approach to inhibit bacterial pathogenesis and to help preserve the efficacy of available antibiotics. This approach requires an improved understanding of the molecular determinants of adhesion to the bladder urothelium. We designed experiments using a custom-built live cell monolayer rheometer (LCMR) to quantitatively measure individual and combined contributions of bacterial cell surface structures [type 1 pili, curli, and phosphoethanolamine (pEtN) cellulose] to bladder cell adhesion. Using the UPEC strain UTI89, isogenic mutants, and controlled conditions for the differential production of cell surface structures, we discovered that curli can promote stronger adhesive interactions with bladder cells than type 1 pili. Moreover, the coproduction of curli and pEtN cellulose enhanced adhesion. The LCMR enables the evaluation of adhesion under high-shear conditions to reveal this role for pEtN cellulose which escaped detection using conventional tissue culture adhesion assays. Together with complementary biochemical experiments, the results support a model wherein cellulose serves a mortar-like function to promote curli association with and around the bacterial cell surface, resulting in increased bacterial adhesion strength at the bladder cell surface.

Association between TLR4 polymorphisms (896 A>G, 1196 C>T, - 2570 A>G, - 2081 G>A) and virulence factors in uropathogenic Escherichia coli.

Escherichia coli is the main etiological agent of urinary tract infections. Its virulence factors are important during the initial interaction stage with the host as they enable colonization of urinary tract tissues. The genetic markers evidencing susceptibility to develop recurrent infections have been previously described. Toll-like receptors are critical sensors of microbial attacks, and they are also effectors of the individual's innate defense for elimination of pathogens. The aim of this study was to evaluate the association between functional polymorphisms (896 A>G, 1196 C>T, - 2570 A>G, - 2081 G>A) and susceptibility to develop urinary tract infections as well as E. coli virulence factors. This study includes 100 samples from patients diagnosed with UTI and 100 samples from uninfected subjects. A conventional urine culture was performed and the isolates were identified by using the Vitek automated system. TLR4 gene polymorphisms were identified by the PCR-RFLP technique. The hlyA, fimH, papC, iutA and cnf1 virulence factors as well as the E. coli phylogenetic group were assessed by PCR. In this study, it was observed that the presence of the - 2570 polymorphism represents a risk of UTI (p < 0.01), whereas - 2081 confers protection (p < 0.01). The 896A>G and 1196C>T polymorphisms were associated with the E. coli virulence factors fimH and hlyA, respectively (p < 0.05). The B2 group was the most frequent in clinical isolates (51%), and it displayed more virulence factors regarding other phylogenetic groups (p ≤ 0.05). An interesting finding was that strains considered as commensals, belonging to groups A and B1, can cause UTI and present virulence factors. Polymorphisms occurring in the TLR4 promoter region are correlated with susceptibility or risk of UTI, whereas structural polymorphisms are associated with the recognition of virulence factors displayed by E. coli.

Biofilm Production and Antimicrobial Resistance among Uropathogens in Pediatric Cases: a Hospital Based Study

The study was designed to provide account of etiological agents of urinary tract infection in pediatric patients and the antimicrobial resistance pattern plus biofilm producing profile of the isolates. The prospective study was conducted in Alka Hospital, Nepal with 353 clean catch urine samples from children. It was obtained during July 2014 to January 2015 which were first cultured by semi-quantitative method, followed by antimicrobial susceptibility testing and biofilm production assay on Congo red agar. Multidrug- resistance, extensively drug- resistance and pandrug- resistance among isolates were considered as per international consensus. Out of 353 samples, 64 (18.13%) showed positive growth in culture, confirming urinary tract infection. E. coli, 44 (68.8%) was the predominant organism followed by Klebsiella spp. 6 (14.1%). Most E. coli were sensitive to amikacin (93.2%) followed by nitrofurantoin (86.4%), and highly resistant to ampicillin (95.5%). Of 64 isolates, 23 (35.93%) were found to be multidrug- resistant strains. Biofilm was produced by 36 (56.25%) isolates. This study showed higher biofilm production and resistance to in-use antibiotics rendering ineffective for empirical use. Regular surveillance of resistance patterns should be done to regulate multidrug- resistant bugs and to ensure effective management of urinary tract infection in children in a tertiary care setups.