Extraintestinal Pathogen Research Articles

Comparative phenotypic characterization of hybrid Shiga toxin-producing / uropathogenic Escherichia coli, canonical uropathogenic and Shiga toxin-producing Escherichia coli

Hybrid Shiga toxin (Stx)-producing Escherichia coli (STEC) and uropathogenic E. coli (UPEC) strains are phylogenetically positioned between STEC and UPEC and can cause both diarrhea and urinary tract infections (UTIs). However, their virulence properties and adaptation to different host milieu in comparison to canonical UPEC and STEC strains are unknown.We determined phenotypes of the STEC/UPEC hybrid with respect to virulence including acid resistance, motility, biofilm formation, siderophore production, and adherence to human colonic Caco-2 and bladder T24 cells and compared to phenotypes of commensal strain MG1655, UPEC strain 536, and STEC strains B2F1 and Sakai. Moreover, we assessed the adaptation of the hybrid to artificial urine medium (AUM) and simulated colonic environment medium (SCEM).Overall acid resistance at pH 2.5 was high except in strains B2F1 and hybrid 05−00787 which showed reduced and extremely low acid resistance, respectively. Motility was reduced in hybrid 05−00787 and 09−05501 but strong in the remaining hybrids. While some hybrids showed high biofilm formation in LB, overall biofilm formation in SCEM and AUM were low and non-existent, respectively. All strains tested showed siderophore activity at equilibrium. All strains except MG1655 adhered to Caco-2 cells with the hybrid having similar adherence when compared to 536 but exhibited 2 and 3 times lower adherence when compared to B2F1 and Sakai, respectively. All Stx-producing strains adhered stronger to T24 cells than strains 536 and MG1655. Overall growth in LB, SCEM and AUM was consistent within the hybrid strains, except hybrid 05−00787 which showed significantly different growth patterns.Our data suggest that the hybrid is adapted to both, the intestinal and extraintestinal milieu. Expression of phenotypes typical of intestinal and extraintestinal pathogens thereby supports its potential to cause diarrhea and UTI.

Identification of Risk Factors for Invasive Extraintestinal Pathogenic Escherichia coli (ExPEC) Disease

Background: A pathogenic group of invasive extraintestinal pathogenic (ExPEC) Escherichia coli possess the ability to infect normally sterile body sites and cause severe invasive ExPEC disease (IED). ExPEC is a leading cause of bacteremia and sepsis worldwide and is associated with older age and multidrug-resistant infections. Janssen Vaccines & Prevention is developing a novel multivalent glycoconjugate vaccine to prevent IED. We aimed to use an unbiased approach, with no prespecified potential risk factors, using machine-learning models, to screen for and identify IED risk factors for further validation. Methods: We used a patient-level prediction study design to model the probability of a patient developing IED within 14 days to 1 year from a given date based on their prior 2 years of health records. We used the Optum EHR database (~98 million subjects) in the common data model (CDM) format, with health features encoded in the following categories: conditions, procedures, drugs, healthcare visits, recent laboratory measurements, and age and gender. A gradient boosting model (XGBoost) was used with Shapley additive explanation (SHAP) values to identify which features were most important to the model’s decisions and to characterize precisely the relationship between features and outcomes (binary or continuous). Results: Study participants were aged ≥60 years at index with no previously recorded IED. Of ~6,500,000 cases included, ~8,000 had IED during the prediction window. We found that having ≥1 urinary tract infection (UTI) in the retrospective period increased the model’s probability of predicting IED for that patient, with more frequent or more recent UTIs increasing IED prediction chance (Figure 1). Higher age linearly increased the model’s likelihood of predicting that a patient would develop IED. The model also identified ≥1 inpatient or ER visit and laboratory values indicative of renal or immune dysfunction to be correlated with increased IED risk. This methodology is a generalizable approach to screening for potential risk factors for an outcome using EHR databases; it requires little to no prespecification of the health factors or precise relationship between the factors and outcome. Conclusions: Using a new, impartial methodology (with no prespecification), older age and a history of UTIs were key predictive features for IED, factors previously identified through traditional analysis, confirming the validity of the methodology. Novel features, including recent hospitalization, were shown to increase IED risk relative to existing criteria. Our findings may be used to inform the clinical development of preventive strategies.Funding: Janssen Research and DevelopmentDisclosures: None

Population structure and uropathogenic potential of extended-spectrum cephalosporin-resistant Escherichia coli from retail chicken meat

BackgroundFood-producing animals and their products are considered a source for human acquisition of antimicrobial resistant (AMR) bacteria, and poultry are suggested to be a reservoir for Escherichia coli resistant to extended-spectrum cephalosporins (ESC), a group of antimicrobials used to treat community-onset urinary tract infections in humans. However, the zoonotic potential of ESC-resistant E. coli from poultry and their role as extraintestinal pathogens, including uropathogens, have been debated. The aim of this study was to characterize ESC-resistant E. coli isolated from domestically produced retail chicken meat regarding their population genetic structure, the presence of virulence-associated geno- and phenotypes as well as their carriage of antimicrobial resistance genes, in order to evaluate their uropathogenic potential.ResultsA collection of 141 ESC-resistant E. coli isolates from retail chicken in the Norwegian monitoring program for antimicrobial resistance in bacteria from food, feed and animals (NORM-VET) in 2012, 2014 and 2016 (n = 141) were whole genome sequenced and analyzed. The 141 isolates, all containing the beta-lactamase encoding gene blaCMY-2, were genetically diverse, grouping into 19 different sequence types (STs), and temporal variations in the distribution of STs were observed. Generally, a limited number of virulence-associated genes were identified in the isolates. Eighteen isolates were selected for further analysis of uropathogen-associated virulence traits including expression of type 1 fimbriae, motility, ability to form biofilm, serum resistance, adhesion- and invasion of eukaryotic cells and colicin production. These isolates demonstrated a high diversity in virulence-associated phenotypes suggesting that the uropathogenicity of ESC-resistant E. coli from chicken meat is correspondingly highly variable. For some isolates, there was a discrepancy between the presence of virulence-associated genes and corresponding expected phenotype, suggesting that mutations or regulatory mechanisms could influence their pathogenic potential.ConclusionOur results indicate that the ESC-resistant E. coli from chicken meat have a low uropathogenic potential to humans, which is important knowledge for improvement of future risk assessments of AMR in the food chains.

Inhibitory Effects of <i>Escherichia coli</i> on the Formation and Development of <i>Staphylococcus epidermidis</i> Biofilm

In the present study, we examined whether a commensal gut bacterium Escherichia coli might prevent the formation and development of the biofilm of Staphylococcus epidermidis, a nosocomial extraintestinal pathogen but not a gut microorganism. When co-cultured with S. epidermidis, E. coli strain ATCC 35218, a non-pathogenic strain, was found to be dominant in the biofilm formed on the surface of wells of a microtiter plate. In addition, E. coli significantly incorporated and grew in a niche preoccupied by S. epidermidis biofilm. Two other E. coli strains (strain K-12 and B) also showed to interfere the biofilm formation by S. epidermidis. In contrast, S. epidermidis could not grow in a niche preoccupied by E. coli biofilm. These results suggest that, through inhibition of the formation and development of the biofilm, E. coli may eliminate S. epidermidis from the gastrointestinal tract.

Study of virulence factors and antibiotic susceptibility pattern of extraintestinal pathogenic Escherichia coli

To detect the Virulence factors of extraintestinal pathogenic (ExPEC). To study the antimicrobial susceptibility pattern and Extended spectrum Beta lactamase (ESBL) production by ExPEC. This is a prospective study conducted on ( isolated from extraintestinal sites. A total of 150 ExPEC isolates were obtained from various clinical samples. These isolates were tested for production of Hemolysin, Hemagglutination, Serum resistance and Gelatinase. Isolates were also tested for susceptibility to a set of antimicrobials and for production of an enzyme Extended spectrum Beta lactamase (ESBL). Statistical analyses were done with IBM SPSS Version 22. A “P” Value of <0.05 was considered as significant Among 150 isolates of , 53 (35.3%) were haemolytic, 66 (44%) were positive for serum resistance, 77 (51.3%) were positive for gelatinase and 78 (52%) were positive for Hemagglutination. Antibiotic susceptibility pattern showed that maximum isolates (≈90%) were resistant to Cephalosporins and Ampicillin. Least resistance (13.1%) was shown to Nitrofurantoin in cases of isolates from urine sample. Testing for ESBL production showed that majority (60.7%) of the isolates were confirmed to be ESBL producers. cause various extraintestinal infections because of production of virulence factors & developing drug resistance. Judicious use of antibiotics can prevent drug resistance.

Companion Animals Are Spillover Hosts of the Multidrug-Resistant Human Extraintestinal Escherichia coli Pandemic Clones ST131 and ST1193.

Escherichia coli sequence types 131 (ST131) and 1193 are multidrug-resistant extraintestinal pathogens that have recently spread epidemically among humans and are occasionally isolated from companion animals. This study characterized a nationwide collection of fluoroquinolone-resistant (FQR) E. coli isolates from extraintestinal infections in Australian cats and dogs. For this, 59 cat and dog FQR clinical E. coli isolates (representing 6.9% of an 855-isolate collection) underwent PCR-based phylotyping and whole-genome sequencing (WGS). Isolates from commensal-associated phylogenetic groups A (14/59, 24%) and B1 (18/59, 31%) were dominant, with ST224 (10/59, 17%), and ST744 (8/59, 14%) predominating. Less prevalent were phylogenetic groups D (12/59, 20%), with ST38 (8/59, 14%) predominating, and virulence-associated phylogenetic group B2 (7/59, 12%), with ST131 predominating (6/7, 86%) and no ST1193 isolates identified. In a WGS-based comparison of 20 cat and dog-source ST131 isolates with 188 reference human and animal ST131 isolates, the cat and dog-source isolates were phylogenetically diverse. Although cat and dog-source ST131 isolates exhibited some minor sub-clustering, most were closely related to human-source ST131 strains. Furthermore, the prevalence of ST131 as a cause of FQR infections in Australian companion animals was relatively constant between this study and the 5-year-earlier study of Platell et al. (2010) (9/125 isolates, 7.2%). Thus, although the high degree of clonal commonality among FQR clinical isolates from humans vs. companion animals suggests the possibility of bi-directional between-species transmission, the much higher reported prevalence of ST131 and ST1193 among FQR clinical isolates from humans as compared to companion animals suggests that companion animals are spillover hosts rather than being a primary reservoir for these lineages.

Species Transferability of Klebsiella pneumoniae Carbapenemase-2 Isolated from a High-Risk Clone of Escherichia coli ST410.

Sequence type 410 (ST410) of Escherichia coli is an extraintestinal pathogen associated with multi drug resistance. In this study, we aimed to investigate the horizontal propagation pathway of a highrisk clone of E. coli ST410 that produces Klebsiella pneumoniae carbapenemase (KPC). blaKPCencoding E. coli and K. pneumoniae isolates were evaluated, and complete sequencing and comparative analysis of blaKPC-encoding plasmids from E. coli and K. pneumoniae, antimicrobial susceptibility tests, polymerase chain reaction, multilocus sequence typing, and conjugal transfer of plasmids were performed. Whole-genome sequencing was performed for plasmids mediating KPC-2 production in E. coli and K. pneumoniae clinical isolates. Strains E. coli CPEc171209 and K. pneumoniae CPKp171210 were identified as ST410 and ST307, respectively. CPEc171209 harbored five plasmids belonging to serotype O8:H21, which is in the antimicrobial-resistant clade C4/H24. The CPKp171210 isolate harbored three plasmids. Both strains harbored various additional antimicrobial resistance genes. The IncX3 plasmid pECBHS_9_5 harbored blaKPC-2 within a truncated Tn4401a transposon, which also contains blaSHV-182 with duplicated conjugative elements. This plasmid displayed 100% identity with the IncX3 plasmid pKPBHS_10_3 from the K. pneumoniae CPKp171210 ST307 strain. The genes responsible for the conjugal transfer of the IncX3 plasmid included tra/trb clusters and pil genes coding the type IV pilus. ST410 can be transmitted between patients, posing an elevated risk in clinical settings. The emergence of a KPC-producing E. coli strain (ST410) is concerning because the blaKPC-2-bearing plasmids may carry treatment resistance across species barriers. Transgenic translocation occurs among carbapenem-resistant bacteria, which may spread rapidly via horizontal migration.

Escherichia coli ST131 clones harbouring AggR and AAF/V fimbriae causing bacteremia in Mozambican children: Emergence of new variant of fimH27 subclone

Multidrug-resistant Escherichia coli ST131 fimH30 responsible for extra-intestinal pathogenic (ExPEC) infections is globally distributed. However, the occurrence of a subclone fimH27 of ST131 harboring both ExPEC and enteroaggregative E. coli (EAEC) related genes and belonging to commonly reported O25:H4 and other serotypes causing bacteremia in African children remain unknown. We characterized 325 E. coli isolates causing bacteremia in Mozambican children between 2001 and 2014 by conventional multiplex polymerase chain reaction and whole genome sequencing. Incidence rate of EAEC bacteremia was calculated among cases from the demographic surveillance study area. Approximately 17.5% (57/325) of isolates were EAEC, yielding an incidence rate of 45.3 episodes/105 children-years-at-risk among infants; and 44 of isolates were sequenced. 72.7% (32/44) of sequenced strains contained simultaneously genes associated with ExPEC (iutA, fyuA and traT); 88.6% (39/44) harbored the aggregative adherence fimbriae type V variant (AAF/V). Sequence type ST-131 accounted for 84.1% (37/44), predominantly belonging to serotype O25:H4 (59% of the 37); 95.6% (35/44) harbored fimH27. Approximately 15% (6/41) of the children died, and five of the six yielded ST131 strains (83.3%) mostly (60%; 3/5) due to serotypes other than O25:H4. We report the emergence of a new subclone of ST-131 E. coli strains belonging to O25:H4 and other serotypes harboring both ExPEC and EAEC virulence genes, including agg5A, associated with poor outcome in bacteremic Mozambican children, suggesting the need for prompt recognition for appropriate management.

Characterization of Integrons and Antimicrobial Resistance in Escherichia coli Sequence Type 131 Isolates.

Background Escherichia coli sequence type 131 (ST131) is an important multidrug-resistant extraintestinal pathogen, which can cause many kinds of infections. Integrons may play a crucial role in the dissemination of antibiotic resistance genes. The purpose of this study was to characterize the prevelance of integrons among E. coli ST131 strains in China. Methods Eighty-three E. coli ST131 strains in China. E. coli ST131 strains in China. Results Overall, 26.5% (22/83) of the E. coli ST131 strains in China. dfrA17-aadA5 and aac(6′)-Ib-cr-cmlA5. Only one type of Pc promoter variant was detected among 22 integron-positive isolates (PcW). In vivo transfer of integron was successful for 9 of integron-positive E. coli ST131 strains in China. E. coli ST131 strains in China. Conclusions Our study showed a low prevalence of integrons was detected in E. coli ST131. Continued surveillance of this mobile genetic element should be performed to study the evolution of antibiotic resistance among E. coli ST131.E. coli ST131 strains in China. E. coli ST131 strains in China.

Determination of Antibiotic Resistance Profile and Virulence Genes in Escherichia coli Isolates from Palestinian Patients

Introduction: Escherichia coli (E. coli) is considered one of the most frequent intestinal and extraintestinal pathogen.
 Methods: A total of 49 isolates of E. coli were collected from different clinical samples, from different hospitals in Northern West Bank-Palestine, during January-March 2019.
 Aims: To detect the distribution of Type III secretion system (T3SS) genes, class 1, 2 and 3 integrons, virulence factors (fyuA, papGIII, iutA and sfa⁄foc) using multiplex PCR and antibiotic resistance using disc diffusion method.
 Results: In this study, E. coli isolates showed high resistance rate against different types of antibiotics and 71.4% of the isolates were multidrug resistant (MDR). Only class 1 integron was detected in these isolates with prevalence 57%, and 65.7% of MDR isolates carried integron genes. The prevalence of T3SS genes was 0.0%. In addition, results of this study showed that the prevalence of virulence genes papGIII, sfa⁄foc, fyuA and iutA was 4.1%, 40%, 64%, and 79.6%, respectively.
 Conclusions: The isolates of E. coli showed high resistance rate against different types of antibiotics. The co-occurrence of class 1 integrons and antimicrobial resistance genes in these isolates is an additional threat for spread of the antimicrobial resistance traits which may further complicate future strategies for treatment the infections caused by this pathogen. In addition, E. coli isolated from Palestinian patients showed one or more virulence factors that could increase their pathogenic potential.

Australian porcine clonal complex 10 (CC10) Escherichia coli belong to multiple sublineages of a highly diverse global CC10 phylogeny.

We recently identified clonal complex 10 (CC10) Escherichia coli as the predominant clonal group in two populations of healthy Australian food-production pigs. CC10 are highly successful, colonizing humans, food-production animals, fresh produce and environmental niches. Furthermore, E. coli within CC10 are frequently drug resistant and increasingly reported as human and animal extra-intestinal pathogens. In order to develop a high-resolution global phylogeny and determine the repertoire of antimicrobial-resistance genes, virulence-associated genes and plasmid types within this clonal group, we downloaded 228 publicly available CC10 short-read genome sequences for comparison with 20 porcine CC10 we have previously described. Core genome single nucleotide polymorphism phylogeny revealed a highly diverse global phylogeny consisting of multiple lineages that did not cluster by geography or source of the isolates. Australian porcine strains belonged to several of these divergent lineages, indicative that CC10 is present in these animals due to multiple colonization events. Differences in resistance gene and plasmid carriage between porcine strains and the global collection highlighted the role of lateral gene transfer in the evolution of CC10 strains. Virulence profiles typical of extra-intestinal pathogenic E. coli were present in both Australian porcine strains and the broader collection. As both the core phylogeny and accessory gene characteristics appeared unrelated to the geography or source of the isolates, it is likely that the global expansion of CC10 is not a recent event and may be associated with faecal carriage in humans.

Escherichia coli ST131- H 22 as a Foodborne Uropathogen

Escherichia coli sequence type 131 (ST131) has emerged rapidly to become the most prevalent extraintestinal pathogenic E.coli clones in circulation today. Previous investigations appeared to exonerate retail meat as a source of human exposure to ST131; however, these studies focused mainly on extensively multidrug-resistant ST131 strains, which typically carry allele 30 of the fimH type 1 fimbrial adhesin gene (ST131-H30). To estimate the frequency of extraintestinal human infections arising from foodborne ST131 strains without bias toward particular sublineages or phenotypes, we conducted a 1-year prospective study of E.coli from meat products and clinical cultures in Flagstaff, Arizona. We characterized all isolates by multilocus sequence typing, fimH typing, and core genome phylogenetic analyses, and we screened isolates for avian-associated ColV plasmids as an indication of poultry adaptation. E.coli was isolated from 79.8% of the 2,452 meat samples and 72.4% of the 1,735 culture-positive clinical samples. Twenty-seven meat isolates were ST131 and belonged almost exclusively (n = 25) to the ST131-H22 lineage. All but 1 of the 25 H22 meat isolates were from poultry products, and all but 2 carried poultry-associated ColV plasmids. Of the 1,188 contemporaneous human clinical E.coli isolates, 24 were ST131-H22, one-quarter of which occurred in the same high-resolution phylogenetic clades as the ST131-H22 meat isolates and carried ColV plasmids. Molecular clock analysis of an international ST131-H22 genome collection suggested that ColV plasmids have been acquired at least six times since the 1940s and that poultry-to-human transmission is not limited to the United States.IMPORTANCEE.coli ST131 is an important extraintestinal pathogen that can colonize the gastrointestinal tracts of humans and food animals. Here, we combined detection of accessory traits associated with avian adaptation (ColV plasmids) with high-resolution phylogenetics to quantify the portion of human infections caused by ST131 strains of food animal origin. Our results suggest that one ST131 sublineage-ST131-H22-has become established in poultry populations around the world and that meat may serve as a vehicle for human exposure and infection. ST131-H22 is just one of many E.coli lineages that may be transmitted from food animals to humans. Additional studies that combine detection of host-associated accessory elements with phylogenetics may allow us to quantify the total fraction of human extraintestinal infections attributable to food animal E.coli strains.

Contribution of yersiniabactin to the virulence of an Escherichia coli sequence type 69 (“clonal group A”) cystitis isolate in murine models of urinary tract infection and sepsis

Escherichia coli sequence type 69 (ST69; “clonal group A”) is an important extraintestinal pathogen. To clarify the yersiniabactin siderophore system's role in ST69's extraintestinal virulence we compared a wild-type ST69 cystitis isolate, isogenic irp2 (yersiniabactin) mutants, and irp2-complemented mutants in murine models of sepsis and urinary tract infection (UTI). irp2 mutants were attenuated mildly in the UTI model and profoundly in the sepsis model. In both models, complementation with a functional copy of irp2 restored full parental virulence. These findings suggest that in ST69 the yersiniabactin system has a minor role in urovirulence and a major role in sepsis causation.

Genetic Ablation of Butyrate Utilization Attenuates Gastrointestinal Salmonella Disease

Salmonella enterica serovar (S.) Typhi is an extraintestinal pathogen that evolved from Salmonella serovars causing gastrointestinal disease. Compared with non-typhoidal Salmonella serovars, the genomes of typhoidal serovars contain various loss-of-function mutations. However, the contribution of these genetic differences to this shift in pathogen ecology remains unknown. We show that the ydiQRSTD operon, which is deleted in S. Typhi, enables S. Typhimurium to utilize microbiota-derived butyrate during gastrointestinal disease. Unexpectedly, genetic ablation of butyrate utilization reduces S. Typhimurium epithelial invasion and attenuates intestinal inflammation. Deletion of ydiD renders S. Typhimurium sensitive tobutyrate-mediated repression of invasion gene expression. Combined with the gain of virulence-associated (Vi) capsular polysaccharide and loss of very-long O-antigen chains, two features characteristic of S. Typhi, genetic ablation of butyrate utilization abrogates S. Typhimurium-induced intestinal inflammation. Thus, the transition from a gastrointestinal to an extraintestinal pathogen involved discrete genetic changes, providing insights into pathogen evolution and emergence.

Survey on Biofilm Production and Presence of Attachment Factors in Human Uropathogenic Strains of Escherichia coli

Background: Escherichia coli is one of the most common causes of different infections. Biofilm structure allows the strains to persist on the biotic and abiotic surfaces for a long time and impairs eradication. Surface colonization of E. coli could be done with several extracellular appendages, which are effective productive events leading to biofilm maturity. Objectives: In this study, the possible relationship between the presence of fimA (encoding large subunit of Type I fimbriae) and csgA (encoding curli fimbriae) genes with biofilm formation in extraintestinal pathogen E. coli isolates was evaluated. Methods: For this study, 35 isolates of E. coli were collected from human urine samples of those referred to oil big hospital. After isolating and identifying E. coli strains by common biochemical tests, we examined the biofilm formation of isolates in brain heart infusion broth, which contained 3% sucrose, using microtiter plate crystal violet method. Presence of the 2 studied genes in the isolates was evaluated using multiplex polymerase chain reaction (m-PCR) assay. Results: In the present study, 27 strains from 35 isolates were expressed in the 2 studied attachment- associated factors, but 5 and 2 strains were expressed by csgA and fimA, respectively. Except 2 strains that could not produce biofilm, 1 strain was detected as a moderate biofilm producer, and the 32 remaining strains were detected as weak biofilm producers. Conclusions: All the positive and the 2 negative biofilm producer strains could be expressed in the 2 studied genes. The correlation between the presence of studied genes and biofilm production ability was suspected, but because of the high percentage of biofilm production in the studied strains, the need to use good hygiene practices is highly recommended.

Genetic Attributes of E. coli Isolates from Chlorinated Drinking Water.

Escherichia coli, is intimately associated with both human health and water sanitation. E. coli isolates from water can either be (i) host associated commensals, indicating recent faecal contamination; (ii) diarrheal pathogens or (iii) extra-intestinal pathogens that pose a direct health risk; or (iv) free-living. In this study we genetically characterised 28 E. coli isolates obtained from treated drinking water in south eastern Australia to ascertain their likely source. We used full genome sequencing to assign the isolates to their phylogenetic group and multi-locus sequence type. The isolates were also screened in silico for several virulence genes and genes involved in acquired antibiotic resistance. The genetic characteristics of the isolates indicated that four isolates were likely human pathogens. However, these isolates were not detected in sufficient numbers to present a health risk to the public. An additional isolate was a human associated strain. Nine isolates were water associated free-living strains that were unlikely to pose a health risk. Only 14% of the isolates belonged to the host associated phylogenetic group (B2) and only a single isolate had any antibiotic resistance genes. This suggests that the primary source of the drinking water E. coli isolates may not have been recent human faecal contamination.

Escherichia coli clonal group A among uropathogenic infections in Mexico City.

Escherichia coli clonal group A (CGA) causes urinary tract and other extra-intestinal infections in humans. CGA is an important cause of trimethoprim/sulfamethoxazole (SXT) resistance in extra-intestinal pathogens. We examined the extent to which resistance in this area is related to CGA dissemination of E. coli from urinary tract infections (UTIs) in Mexico City. The virulence backgrounds of the isolates were also characterized. In this study, the frequency of resistance to SXT used for UTI treatment was high (56-65 %), and CGA isolates accounted for 9 of the 78 SXT-resistant isolates (11.5 %). Although all CGA isolates were found to be multidrug resistant (MDR), none of them were extended-spectrum β-lactamase-producing organisms. The prevalence of CGA among the 45 MDR isolates that we identified was 20 %, indicating that this clonal group moderately contributes to the antibiotic resistance of uropathogenic E. coli isolates in this region. Most of the nine CGA isolates carried transferable, large-size plasmids of approximately 80 to 100 kb, which were able to transfer antimicrobial resistance to E. coli J53 in mating assays. CGA isolates mainly belonged to phylogenetic groups F and D. We found no association between antimicrobial resistance and virulence-associated genes: the median virulence scores of CGA isolates were slightly higher (4.6) than those of non-CGA isolates, whether they were susceptible (3.7) or resistant (3.5) to SXT. Our results indicate that CGA is not a major contributor to the high level of resistance to SXT in this region but, instead, seems to be an important constituent of MDR isolates from UTIs.

Garlic as a functional food

Garlic has been used, for thousands of years both as a food and for medicinal purposes. Garlic can be used as a food preservative to inhibit the growth of pathogens and as a remedy for the treatment or prevention of a number of diseases. The purported health benefits of garlic are numerous, including, anticarcinogenic, antibiotic, anti-hypertensive, and cholesterol-lowering properties, the risk of cardiovascular disease lowering the effects of hypolipidemic, antithrombotic, anti-diabetic, and anti-hyperhomo cysteinemia and, antioxidant, antimicrobial, immunomodulatory, antiasthmatic, antimutagenic, and prebiotic activities. The biologically active substances of garlic can be divided into two main groups; sulphur compounds and sulphur-free active substances. The main sulfur compounds are allicin and alliin. Allicin is the most biologically active compound of garlic. Allicin is not present in raw garlic, but it is rapidly produced by the action of allinase on alliin. Allinase is activated by crushing or chopping, garlic cloves. Allicin exhibits hypolipidemic, antiplatelet, and procirculatory effects and includes antibacterial, anticancer and chemopreventive activities. The group of sulphur-free active substances includes flavonols, antibiotics garlicin, allistatin, adenosine, sapogenins, and saponin. The biological effects of additional constituents of intact garlic, such as lectins, prostaglandins, adenosine, pectin, vitamins B1, B2, B6, C and E, biotin, nicotinic acid, glycolipids, fatty acids, phospholipids and essential amino acids, are well known and the importance of pharmacological activities, such as antifungal, antibacterial antitumor, anti-inflammatory and hypocholesterolemic properties of certain steroid saponins and sapogenins has recently been recorded. Also, garlic is rich in fructooligosaccharides. Fructooligosaccharides are types of prebiotics. Fructooligosaccharides contribute to the reduction of risk of many diseases. They have functional properties, such as improving blood parameters, enhancing resistance against intestinal, as well as extra-intestinal pathogens, modulating immune responses, and decreasing allergies. In this paper, the bioactive compounds of garlic and itRSQUOs physiological role on human health have been discussed.

Virulence factors and antimicrobial resistance in Escherichia coli strains isolated from hen egg shells

Eggs may contain extraintestinal pathogenic (ExPEC) and diarrheogenic (DEC) Escherichia coli which in addition may carry antibiotic resistance. The wide use of biocides and disinfectants in the food industry may induce biocide tolerance in bacteria. The aim of the present study was to evaluate biocide tolerance and antibiotic resistance in E. coli from hen egg shells. A total of 27 isolates obtained from a screening of 180 eggs were studied. Seven isolates carried both eae and bfpA genes of typical enteropathogenic E. coli (EPEC) strains, while 14 isolates only carried eae associated with atypical EPEC strains. Shiga toxin genes stx and stx2 were detected in four isolates. Heat-stable and heat-labile enterotoxin genes as well as aggR were also detected. Several isolates had minimum inhibitory concentrations (MICs) that were higher than the wild-type for the biocide hexadecylpyridinium chloride (HDP, 18.52%) or the commercial disinfectant P3 oxonia (OX, 14.81%). Antibiotic resistance was detected for ampicillin (37.03%), streptomycin (37.03%), tetracycline (37.03%), chloramphenicol (11.11%), nalidixic acid (18.51%) and trimethoprim-sulfamethoxazole (14.81%). Eight isolates (29.63%) were biocide tolerant and antibiotic resistant. Efflux pump genes detected included acrB (96.29%), mdfA (85.18%) and oxqA (37.03%), in addition to quaternary ammonium compound (QAC) resistance genes qacA/B (11.11%) and qacE (7.40%). Antibiotic resistance genes detected included blaCTX-M-2 (22.22%), blaTEM (3.70%), blaPSE (3.70%), tet(A) (29.63%), tet(B) (29.63%), tet(C) (7.40%), tet(E) (11.11%), aac(6′)-Ib (3.70%), sul1 (14.81%), dfrA12 (3.70%) and dfrA15 (3.70%). Most isolates (96.30%) carried more than one genetic determinant of resistance. The most frequent combinations were efflux pump components acrB and mdfA with tetracycline resistance genes (33.33% of isolates). Isolates carrying QAC resistance genes also carried between 4 and 8 of the additional antimicrobial resistance genes investigated. Regardless of biocide tolerance and antibiotic resistance, all isolates were sensitive to carvacrol (0.25%), thymol (0.125%) and trisodium phosphate (1 to 1.5%), but they exhibited a heterogeneous response to sodium lactate and lysozyme-EDTA combinations that apparently were not related with antibiotic resistance. Results from the study reveal not only a low incidence of biocide tolerance but also the presence of multiple resistance strains carrying multiple genetic determinants of resistance.

Antibiogram Profile of Extraintestinal Pathogenic Escherichia Coli Clinical Isolates From Patients with Urinary Tractinfections at Kericho District Hospital, Kenya

Antibiogram Profile of Extraintestinal Pathogenic Escherichia Coli Clinical Isolates From Patients with Urinary Tractinfections at Kericho District Hospital, Kenya