Human Urinary Tract Infections Research Articles

Insights into mechanism and functional consequences of heme binding to hemolysin-activating lysine acyltransferase HlyC from Escherichia coli

BackgroundTight regulation of heme homeostasis is a critical mechanism in pathogenic bacteria since heme functions as iron source and prosthetic group, but is also toxic at elevated concentrations. Hemolysin-activating lysine-acyltransferase (HlyC) from Escherichia coli is crucial for maturation of hemolysin A, which lyses several mammalian cells including erythrocytes liberating large amounts of heme for bacterial uptake. A possible impact and functional consequences of the released heme on events employing bacterial HlyC have remained unexplored. MethodsHeme binding to HlyC was investigated using UV/vis and SPR spectroscopy. Functional impact of heme association was examined using an in vitro hemolysis assay. The interaction was further studied by homology modeling, molecular docking and dynamics simulations. ResultsWe identified HlyC as potential heme-binding protein possessing heme-regulatory motifs. Using wild-type protein and a double alanine mutant we demonstrated that heme binds to HlyC via histidine 151 (H151). We could show further that heme inhibits the enzymatic activity of wild-type HlyC. Computational studies illustrated potential interaction sites in addition to H151 confirming the results from spectroscopy indicating more than one heme-binding site. ConclusionsTaken together, our results reveal novel insights into heme-protein interactions and regulation of a component of the heme uptake system in one of the major causative agents of urinary tract infections in humans. General significanceThis study points to a possible novel mechanism of regulation as present in many uropathogenic E. coli strains at an early stage of heme iron acquisition from erythrocytes for subsequent internalization by the bacterial heme-uptake machinery.

Ni(II) Uptake by Yersiniabactin, a Metallophore Produced by Uropathogenic E. coli

Metal ions can play dual roles as nutrients and toxins in the interaction between bacteria and their environments. E. coli isolates associated with urinary tract infections (UTIs) deploy siderophores, small molecule chelators defined by their ability to competitively bind iron(III) and deliver it to the cell. Yersiniabactin (Ybt) is a virulence‐associated siderophore of uropathogenic E. coli (UPEC) and was recently appreciated to also bind copper during UTIs in humans, forming Cu(II)‐Ybt complexes. Copper binding by Ybt was found to protect E. coli from copper toxicity and also to mediate controlled copper import for nutritional purposes. We have termed this process nutritional passivation. Ni(II) is generally less abundant than copper but is also a nutrient for E. coli with the potential for toxicity. We show here that the Ybt system of UPEC engages in an analogous nutritional passivation activity with Ni(II). Ybt passivates Ni(II) ions, protecting against Ni(II) toxicity in vitro. We also observe that UPEC can use Ni(II)‐Ybt as a nutrient source for nickel. Using quantitative LC‐MS/MS and isotope labeling, we detect import of Ni(II)‐Ybt and dissociation of the nickel, providing a nickel source for cellular enzymes. The metal‐free Ybt is secreted back outside of the cell to bind other metal ions. These findings broaden the spectrum of Ybt activity, reinforcing its value to UPEC as a true metallophore, capable of binding and importing not only iron, but also copper and nickel.Support or Funding InformationJ.P.H. acknowledges National Institute of Diabetes and Digestive and Kidney Diseases grant R01DK099534. A.E.R. was supported by the Mr. and Mrs. Spencer T. Olin Fellowship for Women in Graduate Study.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Rapid Growth of Uropathogenic Escherichia coli during Human Urinary Tract Infection.

ABSTRACTUropathogenic Escherichia coli (UPEC) strains cause most uncomplicated urinary tract infections (UTIs). These strains are a subgroup of extraintestinal pathogenic E. coli (ExPEC) strains that infect extraintestinal sites, including urinary tract, meninges, bloodstream, lungs, and surgical sites. Here, we hypothesize that UPEC isolates adapt to and grow more rapidly within the urinary tract than other E. coli isolates and survive in that niche. To date, there has not been a reliable method available to measure their growth rate in vivo. Here we used two methods: segregation of nonreplicating plasmid pGTR902, and peak-to-trough ratio (PTR), a sequencing-based method that enumerates bacterial chromosomal replication forks present during cell division. In the murine model of UTI, UPEC strain growth was robust in vivo, matching or exceeding in vitro growth rates and only slowing after reaching high CFU counts at 24 and 30 h postinoculation (hpi). In contrast, asymptomatic bacteriuria (ABU) strains tended to maintain high growth rates in vivo at 6, 24, and 30 hpi, and population densities did not increase, suggesting that host responses or elimination limited population growth. Fecal strains displayed moderate growth rates at 6 hpi but did not survive to later times. By PTR, E. coli in urine of human patients with UTIs displayed extraordinarily rapid growth during active infection, with a mean doubling time of 22.4 min. Thus, in addition to traditional virulence determinants, including adhesins, toxins, iron acquisition, and motility, very high growth rates in vivo and resistance to the innate immune response appear to be critical phenotypes of UPEC strains.

Study of Antibiotic Resistant Pattern of Escherichia coli Isolated from Urinary Tract Infections of Patients of Bangladesh

Urinary tract infections (UTIs) are serious health affecting problems worldwide. Urinary tract infection (UTI) can be caused by a lot of bacteria. Among them, E. coli is one of the main causes of both nosocomial and community acquired Urinary tract infections in humans. Drug resistance of E. coli is becoming alarming with the passage of time worldwide in general and in third world countries in particular. The study was intended to collect and analyze the samples from the patients suffering from Urinary tract infection of two medical of southern region of Bangladesh to reveal the antibiotic resistance pattern of E. coli responsible for Urinary tract infection. 50 samples from each hospital were taken. 36 and 41 samples respectively were identified as E. coli. Antibiotic sensitivity testing was done on Mueller-Hinton agar by Kirby–Bauer disc diffusion method. All samples exhibited a different percentage of resistance where ciprofloxacin was showed evidence of higher resistance rate, which was 63.88% and 70.73% respectively. Higher resistance (63% & 75%) against Ampicillin was also found in patients of both medical. On the other hand, 16% resistance against ceftriaxone and 23.53% resistance against cefotaxime suggesting, they were comparatively more effective.

INHIBITION OF ADHESION OF UROPATHOGENIC ESCHERICHIA COLI TO CANINE AND FELINE UROEPITHELIAL CELLS BY AN EXTRACT FROM CRANBERRY

Uropathogenic Escherichia coli (UPEC) is the main infectious agent of urinary tract infections (UTI) in humans, dogs and cats. Dietary consumption of cranberries is thought to be associated with prevention of UTI in humans based on decreased adhesion of UPEC to uroepithelial cells. The present study evaluated the impact of cranberry extract addition on the attachment of UPEC to canine Madin-Darby Canine Kidney and Crandell-Rees Feline Kidney uroepithelial cells. When the extract was present during bacterial growth or only during adhesion tests, a dose-dependent decrease of UPEC adhesion to all cell types was observed. Bacterial growth was weakly decreased only in the presence of the highest concentration of cranberry extract showing that the anti-adherence effect did not require a bacterial growth inhibitory effect. In conclusion, the addition of cranberry extract has preventive effects on the in vitro bacterial attachment to canine and feline uroepithelial cells in a dose dependent way.

Classification of Avian Pathogenic Escherichia coli (APEC) and Human Uropathogenic Escherichia coli (UPEC) in Phylogenetic Groups and Association with Pathogenicity In Vivo

Background: Avian pathogenic E. coli (APEC) and uropathogenic E. coli (UPEC) are responsible, respectively, for avian colibacillosis and for 80% of urinary tract infections in humans. E. coli control is difficult due to the absence of a reliable method to differentiate pathogenic and commensal strains. Genetic similarity between APEC and UPEC suggests a common ancestral origin and the capability of potentially pathogenic strains to affect human health. The classification in phylogenetic groups facilitates the identification of pathogenic strains. The objective of this work was to classify APEC and UPEC E. coli strains into phylogenetic groups and to associate it with in vivo pathogenicity.Materials, Methods & Results: 460 APEC and 450 UPEC strains, stored in BHI with glycerol at -80°C, were selected. APEC strains were isolated from cellulitis, respiratory tract and poultry litter of broiler flocks from Southern Brazil. The UPEC strains from urinary tract infection were provided by a hospital in Porto Alegre. After DNA extraction, APEC and UPEC strains were classified into four phylogenetic groups (A, B1, B2 and D) by a multiplex-PCR protocol for the detection of the chuA and yjaA genes and the TspE4.C2 DNA fragment. Phylogenetic groups were associated with pathogenicity indexes (PI), presented on a scale of 0 to 10, which were previously obtained through the inoculation of APEC strains in one-day-old chicks. Phylogenetic groups were also associated with the presence of 38 virulence-associated genes. The multiplex-PCR protocol was able to differentiate 100% of the APEC and UPEC strains in the four phylogenetic groups. The majority of APEC strains were classified into phylogenetic groups D (31.1%) and B2 (24.1%). On the other hand, the majority of UPEC strains were classified into B2 (53.6%). Among APEC strains, five genes (crl, mat, ompA, fimC and fimH) were detected in more than 80% of strains in all groups. Some genes showed a significant association with specific phylogenetic groups. Gene ireA was exclusively to group D, kpsMT II and cvaC to B2 and sat was exclusively to B1. Four genes (ireA, sfa/focCD, ibeA, tsh) were detected in more than 70% of UPEC strains in all phylogenetic groups. Gene iroN1 showed a significant association exclusively to group A, and iucD, papC and irp2 to B1 group. APEC isolated from poultry litter presented significantly lower PIs than those isolated from cellulitis and from birds with respiratory signs. The average PI from B2 group was significantly higher than that of D group. In addition, the PIs of the two groups were significantly higher than those of A and B1.Discussion: The high frequency of UPEC classified as B2 is in agreement with the literature. More virulent strains are usually classified into B2 group and some of them may be classified into D group. On the other hand, the distribution of APEC isolates in phylogenetic groups is characterized by variability and it is usually related to the origin of the isolates, as observed in the study. Since E. coli strains isolated from human and poultry face similar challenges in infection establishment of extraintestinal sites, they may share some virulence genes. In this study, most of the 38 genes presented a high frequency in both APEC and UPEC strains. As the distribution of APEC strains in phylogenetic groups showed a significant association with pathogenicity, multiplex-PCR becomes an important tool for screening the pathogenicity of strains isolated from the poultry production chain.

Adaptation in a Fibronectin Binding Autolysin of Staphylococcus saprophyticus.

Human-pathogenic bacteria are found in a variety of niches, including free-living, zoonotic, and microbiome environments. Identifying bacterial adaptations that enable invasive disease is an important means of gaining insight into the molecular basis of pathogenesis and understanding pathogen emergence. Staphylococcus saprophyticus, a leading cause of urinary tract infections, can be found in the environment, food, animals, and the human microbiome. We identified a selective sweep in the gene encoding the Aas adhesin, a key virulence factor that binds host fibronectin. We hypothesize that the mutation under selection (aas_2206A>C) facilitates colonization of the urinary tract, an environment where bacteria are subject to strong shearing forces. The mutation appears to have enabled emergence and expansion of a human-pathogenic lineage of S.saprophyticus. These results demonstrate the power of evolutionary genomic approaches in discovering the genetic basis of virulence and emphasize the pleiotropy and adaptability of bacteria occupying diverse niches. IMPORTANCEStaphylococcus saprophyticus is an important cause of urinary tract infections (UTI) in women; such UTI are common, can be severe, and are associated with significant impacts to public health. In addition to being a cause of human UTI, S.saprophyticus can be found in the environment, in food, and associated with animals. After discovering that UTI strains of S.saprophyticus are for the most part closely related to each other, we sought to determine whether these strains are specially adapted to cause disease in humans. We found evidence suggesting that a mutation in the gene aas is advantageous in the context of human infection. We hypothesize that the mutation allows S.saprophyticus to survive better in the human urinary tract. These results show how bacteria found in the environment can evolve to cause disease.

Epigenetic Mechanisms Regulate Innate Immunity against Uropathogenic and Commensal-Like Escherichia coli in the Surrogate Insect Model Galleria mellonella.

Innate-immunity-related genes in humans are activated during urinary tract infections (UTIs) caused by pathogenic strains of Escherichia coli but are suppressed by commensals. Epigenetic mechanisms play a pivotal role in the regulation of gene expression in response to environmental stimuli. To determine whether epigenetic mechanisms can explain the different behaviors of pathogenic and commensal bacteria, we infected larvae of the greater wax moth, Galleria mellonella, a widely used model insect host, with a uropathogenic E. coli (UPEC) strain that causes symptomatic UTIs in humans or a commensal-like strain that causes asymptomatic bacteriuria (ABU). Infection with the UPEC strain (CFT073) was more lethal to larvae than infection with the attenuated ABU strain (83972) due to the recognition of each strain by different Toll-like receptors, ultimately leading to differential DNA/RNA methylation and histone acetylation. We used next-generation sequencing and reverse transcription (RT)-PCR to correlate epigenetic changes with the induction of innate-immunity-related genes. Transcriptomic analysis of G. mellonella larvae infected with E. coli strains CFT073 and 83972 revealed strain-specific variations in the class and expression levels of genes encoding antimicrobial peptides, cytokines, and enzymes controlling DNA methylation and histone acetylation. Our results provide evidence for the differential epigenetic regulation of transcriptional reprogramming by UPEC and ABU strains of E. coli in G. mellonella larvae, which may be relevant to understanding the different behaviors of these bacterial strains in the human urinary tract.

Correlation of Escherichia coli Strains Isolated from Wild Bird Feces and Human Urinary Tract Infections from Phylogenetic Point of View

Background: Escherichia coliis a typical occupant of the enteric system of vertebrates. Some E. coli strains are related to urinary tract infections (UTIs) in human. E. coli strains are divided namely to the four phylogenetic groups, A, B1, B2, and D. Some investigations have indicated the relationship between phylogenetic characteristics and pathogenicity of E. coli. Thus, determining the phylogeny of unknown E. coli strains may be useful in predicting the pathogenesis. Objectives: In the present study, we aimed to compare the distribution of E. coli phylogroups in human UTIs and wild bird feces as a possible source of infection for human in a cross-sectional survey. Methods: A total of 264 E. coli isolates were obtained from human UTIs and feces of wild birds around and phylogenetic determination was carried out using the Clermont Triplex-PCR technique. Results: Our results showed that phylogenetic group B2 strains were the most prevalent in UTI cases (47.2%) followed by group D (30.2%). Group B1 contained 32.5% of the isolates in feces of wild birds, followed by group A (27.5%). There was a significant difference in E. coli phylogeny between hosts so that groups B2 and D were more prevalent in human UTIs and groups B1 and A in wild birds. Also, when comparing the phylogroups within a host, group B1 showed a higher rate in wild birds than in human UTIs. Conclusions: Although the majority of isolates from wild birds belonged to nonpathogenic phylogenetic groups B1 and A, further research seems to necessary to assess the exact relation of wild birds as pathogen sources for human by genotyping E. coli strains via high throughput genotyping assays.

Genetic diversity of the O antigens of Proteus species and the development of a suspension array for molecular serotyping.

Proteus species are well-known opportunistic pathogens frequently associated with skin wound and urinary tract infections in humans and animals. O antigen diversity is important for bacteria to adapt to different hosts and environments, and has been used to identify serotypes of Proteus isolates. At present, 80 Proteus O-serotypes have been reported. Although the O antigen structures of most Proteus serotypes have been identified, the genetic features of these O antigens have not been well characterized. The O antigen gene clusters of Proteus species are located between the cpxA and secB genes. In this study, we identified 55 O antigen gene clusters of different Proteus serotypes. All clusters contain both the wzx and wzy genes and exhibit a high degree of heterogeneity. Potential functions of O antigen-related genes were proposed based on their similarity to genes in available databases. The O antigen gene clusters and structures were compared, and a number of glycosyltransferases were assigned to glycosidic linkages. In addition, an O serotype-specific suspension array was developed for detecting 31 Proteus serotypes frequently isolated from clinical specimens. To our knowledge, this is the first comprehensive report to describe the genetic features of Proteus O antigens and to develop a molecular technique to identify different Proteus serotypes.

Prevalence and Genetic Diversity of Enterococcus faecalis Isolates from Mineral Water and Spring Water in China.

Enterococcus faecalis is an important opportunistic pathogen which is frequently detected in mineral water and spring water for human consumption and causes human urinary tract infections, endocarditis and neonatal sepsis. The aim of this study was to determine the prevalence, virulence genes, antimicrobial resistance and genetic diversity of E. faecalis from mineral water and spring water in China. Of 314 water samples collected from January 2013 to January 2014, 48 samples (15.3%) were contaminated E. faecalis. The highest contamination rate occurred in activated carbon filtered water of spring water (34.5%), followed by source water of spring water (32.3%) and source water of mineral water (6.4%). The virulence gene test of 58 E. faecalis isolates showed that the detection rates of asa1, ace, cylA, gelE and hyl were 79.3, 39.7, 0, 100, 0%, respectively. All 58 E. faecalis isolates were not resistant to 12 kinds of antibiotics (penicillin, ampicillin, linezolid, quinupristin/dalfopristin, vancomycin, gentamicin, streptomycin, ciprofloxacin, levofloxacin, norfloxacin, nitrofurantoin, and tetracycline). Enterobacterial repetitive intergenic consensus-PCR classified 58 isolates and three reference strains into nine clusters with a similarity of 75%. This study is the first to investigate the prevalence of E. faecalis in mineral water and spring water in China. The results of this study suggested that spring water could be potential vehicles for transmission of E. faecalis.

Pandemic extra-intestinal pathogenic Escherichia coli (ExPEC) clonal group O6-B2-ST73 as a cause of avian colibacillosis in Brazil.

Extra-intestinal pathogenic Escherichia coli (ExPEC) represent an emerging pathogen, with pandemic strains increasingly involved in cases of urinary tract infections (UTIs), bacteremia, and meningitis. In addition to affecting humans, the avian pathotype of ExPEC, avian pathogenic E. coli (APEC), causes severe economic losses to the poultry industry. Several studies have revealed overlapping characteristics between APEC and human ExPEC, leading to the hypothesis of a zoonotic potential of poultry strains. However, the description of certain important pandemic clones, such as Sequence Type 73 (ST73), has not been reported in food sources. We characterized 27 temporally matched APEC strains from diverse poultry farms in Brazil belonging to the O6 serogroup because this serogroup is frequently described as a causal factor in UTI and septicemia in humans in Brazil and worldwide. The isolates were genotypically characterized by identifying ExPEC virulence factors, phylogenetically tested by phylogrouping and multilocus sequence type (MLST) analysis, and compared to determine their similarity employing the pulsed field gel electrophoresis (PFGE) technique. The strains harbored a large number of virulence determinants that are commonly described in uropathogenic E. coli (UPEC) and sepsis associated E. coli (SEPEC) strains and, to a lesser extent in neonatal meningitis associated E. coli (NMEC), such as pap (85%), sfa (100%), usp (100%), cnf1 (22%), kpsMTII (66%), hlyA (52%), and ibeA (4%). These isolates also yielded a low prevalence of some genes that are frequently described in APEC, such as iss (37%), tsh, ompT, and hlyF (8% each), and cvi/cva (0%). All strains were classified as part of the B2 phylogroup and sequence type 73 (ST73), with a cluster of 25 strains showing a clonal profile by PFGE. These results further suggest the zoonotic potential of some APEC clonal lineages and their possible role in the epidemiology of human ExPEC, in addition to providing the first description of the O6-B2-ST73 clonal group in poultry.

Capsule Production and Glucose Metabolism Dictate Fitness during Serratia marcescens Bacteremia.

ABSTRACTSerratia marcescens is an opportunistic pathogen that causes a range of human infections, including bacteremia, keratitis, wound infections, and urinary tract infections. Compared to other members of the Enterobacteriaceae family, the genetic factors that facilitate Serratia proliferation within the mammalian host are less well defined. An in vivo screen of transposon insertion mutants identified 212 S. marcescens fitness genes that contribute to bacterial survival in a murine model of bloodstream infection. Among those identified, 11 genes were located within an 18-gene cluster encoding predicted extracellular polysaccharide biosynthesis proteins. A mutation in the wzx gene contained within this locus conferred a loss of fitness in competition infections with the wild-type strain and a reduction in extracellular uronic acids correlating with capsule loss. A second gene, pgm, encoding a phosphoglucomutase exhibited similar capsule-deficient phenotypes, linking central glucose metabolism with capsule production and fitness of Serratia during mammalian infection. Further evidence of the importance of central metabolism was obtained with a pfkA glycolytic mutant that demonstrated reduced replication in human serum and during murine infection. An MgtB magnesium transporter homolog was also among the fitness factors identified, and an S. marcescens mgtB mutant exhibited decreased growth in defined medium containing low concentrations of magnesium and was outcompeted ~10-fold by wild-type bacteria in mice. Together, these newly identified genes provide a more complete understanding of the specific requirements for S. marcescens survival in the mammalian host and provide a framework for further investigation of the means by which S. marcescens causes opportunistic infections.

Complete Genome Sequence of the Uropathogenic Escherichia coli Strain NU14.

ABSTRACTEscherichia coli is the most common bacterium causing urinary tract infections in humans. We report here the complete genome sequence of the uropathogenic Escherichia coli strain NU14, a clinical pyelonephritis isolate used for studying pathogenesis.

Computational identification of potent inhibitors for Streptomycin 3″-adenylyltransferase of Serratia marcescens.

Serratia marcescens is an opportunistic pathogen responsible for the respiratory and urinary tract infections in humans. The antibiotic resistance mechanism of S.marcescens is mediated through aminoglycoside modification enzyme that transfer adenyl group from substrate to antibiotic through regiospecific transfers for the inactivation of antibiotics. Streptomycin 3″-adenylyltransferase acts on the 3' position of the antibiotic and considered as a novel drug target to overcome bacterial antibiotic resistance. Till now, there is no experimentally solved crystal structure of Streptomycin 3″-adenylyltransferase in S.marcescens. Hence, the present study was initiated to construct the three dimensional structure of Streptomycin 3″-adenylyltransferase in order to understand the binding mechanism. The modeled structure was subjected to structure-based virtual screening to identify potent compounds from the five chemical structure databases. Furthermore, different computational methods such as molecular docking, molecular dynamics simulations, ADME toxicity assessment, free energy and density functional theory calculations predicted the structural, binding and pharmacokinetic properties of the best five compounds. Overall, the results suggested that stable binding confirmation of the five potent compounds were mediated through hydrophobic, π-π stacking, salt bridges and hydrogen bond interactions. The identified compounds could pave way for the development of anti-pathogenic agents as potential drug entities.

Human Metabolome-derived Cofactors Are Required for the Antibacterial Activity of Siderocalin in Urine

In human urinary tract infections, host cells release the antimicrobial protein siderocalin (SCN; also known as lipocalin-2, neutrophil gelatinase-associated lipocalin, or 24p3) into the urinary tract. By binding to ferric catechol complexes, SCN can sequester iron, a growth-limiting nutrient for most bacterial pathogens. Recent evidence links the antibacterial activity of SCN in human urine to iron sequestration and metabolomic variation between individuals. To determine whether these metabolomic associations correspond to functional Fe(III)-binding SCN ligands, we devised a biophysical protein binding screen to identify SCN ligands through direct analysis of human urine. This screen revealed a series of physiologic unconjugated urinary catechols that were able to function as SCN ligands of which pyrogallol in particular was positively associated with high urinary SCN activity. In a purified, defined culture system, these physiologic SCN ligands were sufficient to activate SCN antibacterial activity against Escherichia coli. In the presence of multiple SCN ligands, native mass spectrometry demonstrated that SCN may preferentially combine different ligands to coordinate iron, suggesting that availability of specific ligand combinations affects in vivo SCN antibacterial activity. These results support a mechanistic link between the human urinary metabolome and innate immune function.

Effect of Tripterygium Wilfordii Polyglycoside on Experimental Prostatitis Caused by Ureaplasma Urealyticum in Rats.

BackgroundProstatitis is a common and refractory urological disease with complicated etiology. Ureaplasma urealyticum (UU) has a close relationship with human urinary tract infection that can induce nonbacterial prostatitis. Tripterygium wilfordii polyglycoside (TWP) is a non-steroidal immune inhibitor that causes significant immune suppression and anti-inflammatory effects. Its role in prostatitis caused by UU has not yet been established. The aim of this study was to investigate the effect of TWP on UU-infected prostatitis in a rat model.Material/MethodsUU-infected prostatitis SD model rats were randomly divided into 2 groups: the prostatitis group (model group) and the TWP treatment group (treatment group). At 7 days after treatment, prostate weight, leucocyte count, lecithin corpuscles, UU infection rate, and UU microbe count were compared between the 2 groups. Serum inflammatory cytokines TNF-α was determined by ELISA, and ICAM-1 and NF-κB expression were detected.ResultsUU infection rate was 80% after modeling. The rat prostate weight and leucocyte count in the model group increased significantly, while lecithin corpuscles decreased. Compared with controls, inflammatory factor TNF-α, ICAM-1, and NF-κB expression were obviously higher (P<0.05). TWP markedly reduced prostate weight and leucocyte count, increased lecithin corpuscles, and decreased UU microbe count and TNF-α, ICAM-1, and NF-κB expression (P<0.05).ConclusionsTWP can inhibit expression of inflammatory factors and may be useful in treating UU-infected prostatitis through reducing UU infection rate.

English

The VITEK 2 automated system was used for comparing biochemical characteristics of Escherichia coli isolates from human urinary tract infections (UTIs) and camel faecal samples for the first time in the study area. Identification by the system to the species level was accurate. Recovery rate of E. coli from camel specimens was 26% and for human specimens was 33%. Based on biochemical activities, human and animal strains were distributed into 19 profiles. Biochemical profiles 1 and 2, of the classical E. coli activity, comprised 26 camel (50%) and16 human strains (24.2%). The rest human strains (75.8%) were distributed among 10 profiles and 50% camel strains among 7 profiles. E. coli O157 was not confirmed as 6.1% human isolates were β-glucuronidase negative but sorbitol positive whereas, 11.5% camel isolates were sorbitol negative and β-glucuronidase positive. The results showed atypical biochemical reactions but no unique biochemical profile number for E. coli causing community-acquired UTIs in the study area. Phenotypic similarity between camel and human isolates was demonstrated and implication of camel isolates in environmental contamination is discussed. Key words: Escherichia coli, non-O157, VITEK 2, camel, human, Saudi Arabia.

Plasmid Profile Analysis of Aminoglycoside-Resistant Escherichia coli Isolated From Urinary Tract Infections

Background: Uropathogenic E. coli (UPEC) is the primary cause of human urinary tract infections (UTIs) worldwide. Moreover, there has been renewed and growing interest in using older antibiotics for treatment, such as aminoglycosides. Objectives: The goal of this study was to determine the plasmid profile patterns of UPEC isolates harboring the aminoglycoside resistance gene aac(3)-IIa. Patients and Methods: A total of 276 uropathogenic E. coli (UPEC) samples were isolated from UTI patients at the Tehran heart cente rin Tehran, Iran. Antimicrobial susceptibility testing against five aminoglycosides was performed by the disk diffusion method, and the aac(3)-IIa gene was detected via PCR. Moreover, plasmid profiling was carried out on those UPEC isolates harboring the aac(3)-IIa gene. Finally, the similarities among these isolates were determined on the basis of their plasmid profiles. Results: The highest level of resistance was seen for tobramycin (24.6%), and the aac(3)-IIa gene was found in 51 isolates. Twentyseven different plasmid profiles were identified among the isolates harboring the aac(3)-IIa gene, with the 15 kb plasmid being the most common. Moreover, no significant correlation was found between the resistance patterns and the number of plasmids. The cluster analysis based on the plasmid profiles grouped the isolates into five different clusters, of which cluster one was the largest (containing 14 of 51 isolates). Conclusions: Our data suggest the monitoring of aminoglycoside resistance, and its consideration in the empirical therapy of UPEC infections.

Sequential Acquisition of Virulence and Fluoroquinolone Resistance Has Shaped the Evolution of Escherichia coli ST131.

ABSTRACTEscherichia coli ST131 is the most frequently isolated fluoroquinolone-resistant (FQR) E. coli clone worldwide and a major cause of urinary tract and bloodstream infections. Although originally identified through its association with the CTX-M-15 extended-spectrum β-lactamase resistance gene, global genomic epidemiology studies have failed to resolve the geographical and temporal origin of the ST131 ancestor. Here, we developed a framework for the reanalysis of publically available genomes from different countries and used this data set to reconstruct the evolutionary steps that led to the emergence of FQR ST131. Using Bayesian estimation, we show that point mutations in chromosomal genes that confer FQR coincide with the first clinical use of fluoroquinolone in 1986 and illustrate the impact of this pivotal event on the rapid population expansion of ST131 worldwide from an apparent origin in North America. Furthermore, we identify virulence factor acquisition events that predate the development of FQR, suggesting that the gain of virulence-associated genes followed by the tandem development of antibiotic resistance primed the successful global dissemination of ST131.