Virulence factors and phylogenetic grouping of Escherichia coli isolates from patients with bacteraemia of urinary tract origin relate to sex and hospital- vs. community-acquired origin.

Worldwide, Escherichia coli is a leading cause of bloodstream infections. Bacteraemia cases in both community- and hospital-acquired infections are often due to E. coli, and it is a major cause of mortality from these infections. These invasive infections are primarily due to extraintestinal pathogenic E. coli (ExPEC), possessing a variety of virulence factors (VFs). The pathogenesis of E. coli bloodstream infections is largely unknown, which is why preventive measures are lacking. We studied 196 epidemiologically and clinically well-characterized E. coli isolates from patients with bacteraemia of urinary tract origin according to virulence-associated genes (VAGs), phylogroups, and antimicrobial resistance, and the relation of these factors to hospital- vs. community-acquired origin, sex, and mortality. We found papAH to be associated with community-acquired (CA) rather than hospital-acquired (HA) episodes, and kpsM II and hlyD to be associated with HA rather than CA episodes. papAH and iss were associated with females, and iroN with males. Phylogroup D was associated with females. None of the variables was found to be related to mortality. This study provides new insights into the relationships between the epidemiology and pathogenesis of E. coli bacteraemia of urinary tract origin.

Bacterial characteristics of importance for recurrent urinary tract infections caused by Escherichia coli.

Urinary tract infections (UTIs) are among the most common bacterial infectious diseases encountered in clinical practice and account for significant morbidity and high medical costs. Escherichia coli is the most predominant pathogen causing 80-90% of community-acquired UTIs and 30-50% of nosocomially-acquired UTIs. Recurrent UTIs (RUTIs) are reported in 25% of women within 6 months of an acute UTI episode and pose a major problem. The aim of the present thesis was to look for bacterial characteristics of importance for recurrence of UTI caused by E. coli. The thesis is based on three papers. The study is based on E. coli from 236 Swedish women with community-acquired symptomatic lower UTI from a large study of 1162 patients treated with one of three different dosing regimens of pivmecillinam or placebo. The women were evaluated clinically and bacteriologically at the initial visit and at two scheduled follow-up visits. According to pulsed-field gel electrophoresis (PFGE) and culture results all primary infecting E. coli (initial isolates, pretherapy) were assigned into whether the initial infection was followed by cure, persistence, reinfection or relapse during follow-up. The prevalence of virulence factor genes (VFGs), phylogenetic groups, biofilm formation, plasmids and resistance to antimicrobials among primary infecting E. coli causing persistence or relapse at the follow-up visits were compared with the prevalence of these among E. coli followed by cure or reinfection. Previous studies of RUTI using phenotypically based typing methods or less specific DNA based typing methods have concluded, that RUTIs are mainly attributable to reinfection with new strains. However, applying PFGE showed that 77% of RUTIs were caused by a relapse with the primary infecting E. coli (Paper I). This may support the recent observation that E. coli can invade and replicate within the murine bladder forming biofilm-like intracellular bacterial communities (IBCs) and establish quiescent intracellular reservoirs that may represent stable reservoirs for RUTIs. The IBC pathogenic cycle has not been studied in humans; however, recently exfoliated IBCs were detected in urine from women with acute uncomplicated cystitis supporting the presence of the IBC pathway and occurrence of an intracellular bacterial niche in some women with UTI. Based on a triplex PCR E. coli can be divided into four main phylogenetic groups (A, B1, B2 and D). Phylogenetic group B2 was the most predominant group among the primary infecting E. coli followed by group D, A and B1. The majority of the tested 29 VFGs were associated with phylogenetic group B2, whereas only a few VFGs were more broadly distributed among the phylogenetic groups (Paper III). Primary infecting E. coli causing persistence or relapse of the infection were associated with phylogenetic group B2, whereas primary infecting E. coli followed by cure or reinfection were associated with group D (Paper II). Phylogenetic group B2 was associated with susceptibility to many of the tested antimicrobials, whereas group A was associated with resistance to many of these antimicrobials and multidrug resistant (MDR) strains, and group D with MDR strains. Phylogenetic group A and D were associated with carriage of IncH and IncI plasmids, respectively. Resistance patterns or plasmid profiles of the primary infecting E. coli were not associated with outcome during follow-up (cure, persistence, reinfection or relapse) (Paper II). Resistance to ampicillin, sulfamethizole, streptomycin and tetracycline was associated with a lower prevalence of some VFGs (sfa/focDE, agn43bCFT073, chuA, iroN, cnf1, hlyD, ibeA, malX, usp) and higher prevalence of other VFGs (afa/draBC, agn43aCFT073, iha, iutA, sat) but the aggregate VFG score did not differ among the resistant and susceptible strains of these antimicrobials (Paper III). Primary infecting E. coli causing persistence or relapse showed to have a higher biofilm formation capacity in vitro than those being followed by cure or reinfection (Paper II). This indicates that biofilm may be an important determinant for developing RUTI and may support the observation of IBCs. Primary infecting E. coli causing relapse or persistence had a higher aggregate VFG score and higher prevalence of hemolysis and of many of the VFGs than those followed by cure or reinfection. The VFGs associated with persistence or relapse included: adhesins (sfa/focDE, papAH), a biofilm related factor (agn43), iron-uptake systems (chuA, fyuA, iroN), protectins (kpsM II, kpsMII K2), toxins (cnf1, hlyD), a marker of a pathogenicity-associated island from CFT073 (malX), and a bacteriocin-like factor (usp). No specific combination of VFGs could predict persistence or relapse (Paper III). A regimen of three days pivmecillinam therapy for primary infecting E. coli positive for at least one of a number of traits (phylogenetic group B2, sfa/focDE, papAH, agn43, chuA, fyuA, iroN, kpsM II, kpsM II K2, traT, cnf1, hlyD, ibeA, malX, usp and being hemolytic) gave a significantly higher prevalence of persistence or relapse as opposed to primary infecting E. coli subjected to three days therapy with absence of these traits or primary infecting E. coli subjected to seven days therapy irrespective of these traits (Paper III). In conclusion, our results may support the hypothesis of an intracellular reservoir of E. coli in the bladder. The recognition of uropathogenic E. coli as a potential intracellular pathogen challenges our current treatment regimens of UTI and argues for the development of new antimicrobials or treatment regimens/strategies. No distinct virulence profile could predict RUTI. However, we found VFGs associated with persistence or relapse that may be potential targets for prevention and treatment of UTI. Furthermore we identified potential markers that may be used to select a more differentiated and optimal treatment. Future studies must explore the function of these VFGs and other putative and novel VFGs in relation to persistence or relapse of UTI and their possible role in IBC formation. Defining the repertoire and mechanism of VFGs could facilitate the development of new diagnostic tools, regimens and drugs for prevention and treatment of RUTI.

Escherichia coli Causing Recurrent Urinary Tract Infections: Comparison to Non-Recurrent Isolates and Genomic Adaptation in Recurrent Infections.

Recurrent urinary tract infection (rUTI) remains a major problem for many women and therefore the pursuit for genomic and phenotypic traits which could define rUTI has been ongoing. The present study applied a genomic approach to investigate recurrent urinary tract infections by comparative analyses of recurrent and non-recurrent Escherichia coli isolates from general practice. From whole-genome sequencing data, phylogenetic clustering and genomic traits were studied on a collection of isolates which caused recurrent infection compared to non-recurrent isolates. In addition, genomic variation between the 1st and following infection was studied on a subset of the isolates. Evidence of limited adaptation between the recurrent infections based on single nucleotide polymorphism analyses with a range of 0-13 non-synonymous single nucleotide polymorphisms (SNPs) between the paired isolates. This included an overrepresentation of SNPs in metabolism genes. We identified several genes which were more common in rUTI isolates, including nine fimbrial genes, however, not significantly after false-discovery rate. Finally, the results show that recurrent isolates of the present dataset are not distinctive by variation in the core genome, and thus, did not cluster distinct from non-rUTI isolates in a SNP phylogeny.

Influence of Factor V Leiden on susceptibility to and outcome from critical illness: a genetic association study.

INTRODUCTION: Disturbance of the pro-coagulatant and anti-coagulant balance is associated with a poor outcome from critical illness. The objective of this study is to determine whether the Factor V Leiden (FVL) mutation is associated with susceptibility to or death from critical illness. METHODS: A genetic association study involving four case cohorts comprising two Gram negative sepsis, one invasive pneumococcal disease and one intensive care unit cohort with a total of 1,249 patients. Controls were derived from a population-based cohort study (N = 8,147). DNA from patients and controls was genotyped for the FVL mutation. RESULTS: When all patients were investigated together no significant difference in the frequency of FVL mutation was observed compared with controls (odds ratio (OR), 1.03; 95% confidence interval (CI), 0.83 to 1.29). However, when stratified among patients admitted to intensive care (N = 237), susceptibility and the likelihood of long-term death was influenced by the FVL mutation. In adjusted logistic regression analysis, FVL carriers had an increased risk of ICU admission compared to non-carriers (OR 1.62; 95% CI, 1.08 to 2.42). In adjusted Cox regression analysis, FVL carriers were at increased risk of long-term death compared to non-carriers (relative risk 1.78; 95% CI, 1.13 to 2.81). FVL carrier status did not predict either susceptibility to or outcome from Gram negative, Escherichia coli or Streptococcus pneumoniae sepsis. CONCLUSIONS: Overall, the FVL mutation did not appear to increase the risk of admission due to severe invasive infections. Nevertheless, in the subgroup of patients admitted to intensive care an increased risk and a poorer long-term outcome for individuals with critical illness were observed for FVL mutation carriers.

Escherichia coli isolates from broiler chicken meat, broiler chickens, pork, and pigs share phylogroups and antimicrobial resistance with community-dwelling humans and patients with urinary tract infection.

Escherichia coli is the most common cause of urinary tract infection (UTI). Phylogroup B2 and D isolates are associated with UTI. It has been proposed that E. coli causing UTI could have an animal origin. The objective of this study was to investigate the phylogroups and antimicrobial resistance, and their possible associations in E. coli isolates from patients with UTI, community-dwelling humans, broiler chicken meat, broiler chickens, pork, and pigs in Denmark. A total of 964 geographically and temporally matched E. coli isolates from UTI patients (n = 102), community-dwelling humans (n = 109), Danish (n = 197) and imported broiler chicken meat (n = 86), Danish broiler chickens (n = 138), Danish (n = 177) and imported pork (n = 10), and Danish pigs (n = 145) were tested for phylogroups (A, B1, B2, D, and nontypeable [NT] isolates) and antimicrobial susceptibility. Phylogroup A, B1, B2, D, and NT isolates were detected among all groups of isolates except for imported pork isolates. Antimicrobial resistance to three (for B2 isolates) or five antimicrobial agents (for A, B1, D, and NT isolates) was shared among isolates regardless of origin. Using cluster analysis to investigate antimicrobial resistance data, we found that UTI isolates always grouped with isolates from meat and/or animals. We detected B2 and D isolates, that are associated to UTI, among isolates from broiler chicken meat, broiler chickens, pork, and pigs. Although B2 isolates were found in low prevalences in animals and meat, these sources could still pose a risk for acquiring uropathogenic E. coli. Further, E. coli from animals and meat were very similar to UTI isolates with respect to their antimicrobial resistance phenotype. Thus, our study provides support for the hypothesis that a food animal and meat reservoir might exist for UTI-causing E. coli.

[Recurrent diploid biparental mole].

This review summarises the knowledge of recurrent diploid biparental hydatidiform mole, which is a rare genetic condition. Pathogenic variants in both alleles of NLRP7 or KHDC3L are associated with maternal imprinting defects and can cause the condition. Women with biallelic inactivation of NLRP7 can achieve a normal pregnancy by oocyte donation, and it is highly likely, that this applies to women with biallelic inactivation of KHDCL3 as well. Identifying the cause of the recurrent moles can prevent that couples waist time and possibly reduce medical expenses related to fertility treatment.

Characteristics of Escherichia coli causing persistence or relapse of urinary tract infections: phylogenetic groups, virulence factors and biofilm formation.

Recurrent urinary tract infections (RUTIs) pose a major problem but little is known about characteristics of Escherichia coli associated with RUTI. This study includes E. coli from 155 women with community-acquired lower urinary tract infections (UTIs) randomized to one of three dosing regiments of pivmecillinam and aimed to identify associations between the presence of 29 virulence factor genes (VFGs), phylogenetic groups and biofilm formation and the course of infection during follow-up visits at 8-10 and 35-49 days post-inclusion, respectively. E. coli causing persistence or relapse were more often of phylogenetic group B2 and had a significantly higher aggregate VFG score than E. coli that were not detectable at follow-up. Specifically, these E. coli causing persistence or relapse were characterized by a higher prevalence of hemolysis and 12 VFGs (sfa/focDE, papAH, agn43, chuA, fyuA, iroN, kpsM II, kpsM II K2, cnf1, hlyD, malX and usp). KpsM II K2 and agn43a(CFT073) were independently associated with persistence or relapse. No specific combination of presence/absence of VFGs could serve as a marker to predict RUTI. Stratifying for VFGs, seven days of pivmecillinam treatment reduced the prevalence of persistence or relapse of UTI compared with three days. In vitro biofilm formation was not higher among E. coli causing persistence or relapse. The presence of agn43a(CFT073) or agn43b(CFT073) was associated with biofilm forming capacity. In conclusion, our results show potential targets for prevention and treatment of persistence/relapse of UTI and potential markers for selecting treatment lengths and warrant studies of these and new VFGs.

Pulsed-field gel electrophoresis typing of Escherichia coli strains from samples collected before and after pivmecillinam or placebo treatment of uncomplicated community-acquired urinary tract infection in women.

The primary infecting Escherichia coli strains from 156 women with community-acquired uncomplicated urinary tract infection (UTI) randomized to pivmecillinam or placebo and the E. coli strains causing UTI at two follow-up visits were typed using pulsed-field gel electrophoresis (PFGE). In the pivmecillinam treatment group PFGE showed that among patients having a negative urine culture at the first follow-up 77% (46/60) had a relapse with the primary infecting E. coli strain and 23% (14/60) had reinfection with a new E. coli strain at the second follow-up. Among patients having E. coli at the first follow-up PFGE showed that 80% (32/40) had persistence with the primary infecting E. coli strain, 15% (6/40) had reinfection with a new E. coli strain, and 5% (2/40) had different E. coli strains at the two follow-up visits (one had reinfection followed by relapse, and the other had persistence followed by reinfection). In the placebo group the majority had E. coli at the first follow-up. PFGE showed that among these patients 96% (50/52) had persistence with the primary infecting E. coli strain and 4% (2/50) had different E. coli strains at the two follow-up visits (both had persistence followed by reinfection). The finding that the majority of UTIs at follow-up are caused by the primary infecting E. coli strain supports the theory of a vaginal and rectal reservoir but could also support the recent discovery that E. coli strains are able to persist in the bladder epithelium despite appropriate antibiotic treatment, constituting a reservoir for recurrent UTI.