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The effects of intestinal microflora on extraintestinal immune response by intestinal cytokines and metabolites have been documented, but whether intestinal microbes stimulate serum antibody generation is unknown. Here, serum antibodies against 69 outer membrane proteins of Escherichia coli , a dominant bacterium in the human intestine, are detected in 141 healthy individuals of varying ages. Antibodies against E. coli outer membrane proteins are determined in all serum samples tested, and frequencies of antibodies to five outer membrane proteins (OmpA, OmpX, TsX, HlpA, and FepA) are close to 100%. Serum antibodies against E. coli outer membrane proteins are further validated by Western blot and bacterial pull-down. Moreover, the present study shows that OstA, HlpA, Tsx, NlpB, OmpC, YfcU, and OmpA provide specific immune protection against pathogenic E. coli , while HlpA and OmpA also exhibit cross-protection against Staphylococcus aureus infection. These finding indicate that intestinal E. coli activate extraintestinal antibody responses and provide anti-infective immunity.

Escherichia coli EC121 is a multidrug-resistant (MDR) strain isolated from a bloodstream infection of an inpatient with persistent gastroenteritis and T-zone lymphoma that died due to septic shock. Despite causing an extraintestinal infection, previous studies showed that it did not have the usual characteristics of an extraintestinal pathogenic E. coli. Instead, it belonged to phylogenetic group B1 and harbored few known virulence genes. To evaluate the pathogenic potential of strain EC121, an extensive genome sequencing and in vitro characterization of various pathogenicity-associated properties were performed. The genomic analysis showed that strain EC121 harbors more than 50 complete virulence genetic clusters. It also displays the capacity to adhere to a variety of epithelial cell lineages and invade T24 bladder cells, as well as the ability to form biofilms on abiotic surfaces, and survive the bactericidal serum complement activity. Additionally, EC121 was shown to be virulent in the Galleria mellonella model. Furthermore, EC121 is an MDR strain harboring 14 antimicrobial resistance genes, including blaCTX-M-2. Completing the scenario, it belongs to serotype O154:H25 and to sequence type 101-B1, which has been epidemiologically linked to extraintestinal infections as well as to antimicrobial resistance spread. This study with E. coli strain EC121 shows that clinical isolates considered opportunistic might be true pathogens that go underestimated.

Shiga toxin-producing E. coli (STEC) O80:H2 is an uncommon hybrid pathotype that has recently emerged in France. We analysed 18 STEC O80:H2 isolated from humans in Switzerland during 2010–2017. All isolates carried stx2a or stx2d , the rare eae variant eae -ξ and at least seven virulence genes associated with pS88, a plasmid that is found in extraintestinal pathogenic E. coli (ExPEC). Whole genome sequencing (WGS) identified additional chromosomal extraintestinal virulence genes encoding for type 1 fimbria ( fimA, fimC and fimH ), aerobactin ( iuc / iutA ) and afimbrial adhesins ( afaA/C/D/E -VIII). Core genome multi-locus sequence typing (cgMLST) detected two closely related but distinct subclusters with different stx2 and iuc / iutA genotypes. All isolates were multidrug resistant (MDR), but susceptible to third generation cephalosporins and azithromycin. STEC/ExPEC hybrid pathotypes such as STEC O80:H2 represent a therapeutical challenge in the event of extraintestinal infection. [ABSTRACT FROM AUTHOR]

Extraintestinal pathogenic Escherichia coli (ExPEC) include avian pathogenic E. coli (APEC), neonatal meningitis E. coli (NMEC), and uropathogenic E. coli (UPEC) and are responsible for significant animal and human morbidity and mortality. This study sought to investigate if biofilm formation by ExPEC likely contributes to these losses since biofilms are associated with recurrent urinary tract infections, antibiotic resistance, and bacterial exchange of genetic material. Therefore, the goal of this study was to examine differences in biofilm formation among a collection of ExPEC and to ascertain if there is a relationship between their ability to produce biofilms and their assignment to phylogenetic groups in three media types - M63, diluted TSB, and BHI. Our results suggest that ExPEC produce relatively different levels of biofilm formation in the media tested as APEC (70.4%, p = 0.0064) and NMEC (84.4%, p = 0.0093) isolates were poor biofilm formers in minimal medium M63 while UPEC isolates produced significantly higher ODs under nutrient-limited conditions with 25% of strains producing strong biofilms in diluted TSB (p = 0.0204). Additionally, E. coli phylogenetic assignment using Clermont's original and revised typing scheme demonstrated significant differences among the phylogenetic groups in the different media. When the original phylogenetic group isolates previously typed as group D were phylogenetically typed under the revised scheme and examined, they showed substantial variation in their ability to form biofilms, which may explain the significant values of revised phylogenetic groups E and F in M63 (p = 0.0291, p = 0.0024). Our data indicates that biofilm formation is correlated with phylogenetic classification and subpathotype or commensal grouping of E. coli strains. [ABSTRACT FROM AUTHOR]

The emergence of new antibiotic-resistant Escherichia coli pathotypes associated with human disease has led to an investigation in terms of the origins of these pathogens. According to the Centers for Disease Control and Prevention, unspecified agents are responsible for 38.4 million of the 48 million (80%) cases of foodborne illnesses each year in the United States. It is hypothesized that environmental E. coli not typically associated with the ability to cause disease in humans could potentially be responsible for some of these cases. In order for an environmental E. coli isolate to have the ability to cause foodborne illness, it must be able to utilize the same attachment and virulence mechanisms utilized by other human pathogenic E. coli. Recent research has shown that many avian pathogenic E. coli ( APEC) isolated from poultry harbour attachment and virulence genes also currently found in human pathogenic E. coli isolates. Research also suggests that, in addition to the ability to cause gastrointestinal illnesses, APEC may also be an etiological agent of foodborne urinary tract infections ( FUTIs). The purpose of this article was to evaluate the evidence pertaining to the ability of APEC to cause disease in humans, their potential for zoonotic transfer along with discussion on the types of illnesses that may be associated with these pathogens. [ABSTRACT FROM AUTHOR]

The article offers information on a study regarding the genetic analysis of Escherichia coli bacteria isolated from birds, retail poultry meat and human extraintestinal infection. It reports that the study aimed at comparing multilocus sequence analysis and virulence genotyping of all the isolated Escherichia coli from poultry and humans. It informs that the study observed no similar pattern in host source through multilocus sequence analysis which indicates that human, avian, and retail meat isolates are diverse in nature.

The clone Escherichia coli O25 ST131, typically producing extended-spectrum beta-lactamases ( ESBLs), has spread globally and became the dominant type among extraintestinal isolates at many parts of the world. However, the reasons behind the emergence and success of this clone are only partially understood. We compared the core type genes by PCR of ESBL-producing and ESBL-nonproducing strains isolated from urinary tract infections in the United Arab Emirates and found a surprisingly high frequency of the K-12 core type (44.6%) among members of the former group, while in the latter one, it was as low (3.7%), as reported earlier. The high figure was almost entirely attributable to the presence of members of the clone O25 ST131 among ESBL producers. Strains from the same clone isolated in Europe also carried the K-12 core type genes. Sequencing the entire core operon of an O25 ST131 isolate revealed a high level of similarity to known K-12 core gene sequences and an almost complete identity with a recently sequenced non- O25 ST131 fecal isolate. The exact chemical structure and whether and how this unusual core type contributed to the sudden emergence of ST131 require further investigations. [ABSTRACT FROM AUTHOR]

Extraintestinal pathogenic Escherichia coli (ExPEC) are pathogens involved in several disease conditions, ranging from urinary tract infection to meningitis in humans and animals. They comprise epidemiologically and phylogenetically distinct strains, affecting most species and involving any organ or anatomical site. Here, we report fatal cases of necrotizing pneumonia in cats. Over a 1-week period, 13 cats from an animal shelter in Stamford, Connecticut were presented for necropsy. All had a clinical history of acute respiratory disease. The gross and microscopic findings for all the cats were consistent. Escherichia coli was uniformly isolated from the lungs of all the tested cats. All the isolates were haemolytic, genetically related as determined by enterobacterial repetitive intergenic consensus PCR, and harboured genes encoding for cytotoxic necrotizing factor-1 and fimbriae and adhesions that are characteristic of ExPEC, implying a point source clonal outbreak. As cats are common household pets, this report raises concerns regarding zoonotic potential (in either direction) for these ExPEC strains. [ABSTRACT FROM AUTHOR]

Abstract: The triplex PCR of Clermont et al. [Clermont, O., Bonacorsi, S., Bingen, E., 2000. Rapid and simple determination of the Escherichia coli phylogenetic groups. Appl. Environ. Microbiol. 66, 4555–4558.] was used to genotype E. coli isolates from the Mid-Atlantic region of the USA, obtained from freshwater, animal internal organs, and feces. Of 445 isolates subjected to genotyping, 118 isolates (26%) were genotype A, 111 (25%) genotype D, 140 (31%) genotype B1, and 76 (17%) genotype B2. All four genotypes were present in three sets of freshwater stream samples. When isolates from chicken cecal ingesta, cecal mucosa, and tracheal mucosa were screened, there was selective distribution of genotypes in these organs. Genotype D was rarely encountered in feces, milk, and intestinal tissues of dairy cows, while all four genotypes were represented in goose feces. Isolates from the feces of zoo animals reared in the US demonstrated a predominance of genotype B1. Thirty-six of the A isolates in our overall collection were subgenotype A0, in which none of the three amplicons are observed; confirmation that these isolates were E. coli was done using an ancillary lacZ PCR assay. We conclude that the genotyping triplex PCR assay, used in combination with traditional culture methods, can be useful in categorizing E. coli from environmental and veterinary sources in the Mid-Atlantic region of the USA. [Copyright &y& Elsevier]

The development of surface-attached biofilm bacterial communities is considered an important source of nosocomial infections. Recently, bacterial interference via signaling molecules and surface active compounds was shown to antagonize biofilm formation, suggesting that nonantibiotic molecules produced during competitive interactions between bacteria could be used for biofilm reduction. Hence, a better understanding of commensal/pathogen interactions within bacterial community could lead to an improved control of exogenous pathogens. To reveal adhesion or growth-related bacterial interference, we investigated interactions between uropathogenic and commensal Escherichia coil in mixed in vitro biofilms. We demonstrate here that the uropathogenic strain CFT073 and all E. coli expressing group II capsules release into their environment a soluble polysaccharide that induces physicochemical surface alterations, which prevent biofilm formation by a wide range of Gram-positive and Gram-negative bacteria. We show that the treatment of abiotic surfaces with group II capsular polysaccharides drastically reduces both initial adhesion and biofilm development by important nosocomial pathogens. These findings identify capsular polymers as antiadhesion bacterial interference molecules, which may prove to be of significance in the design of new strategies to limit biofilm formation on medical in dwelling devices. [ABSTRACT FROM AUTHOR]

Escherichia coli EC121 is a multidrug-resistant (MDR) strain isolated from a bloodstream infection of an inpatient with persistent gastroenteritis and T-zone lymphoma that died due to septic shock. Despite causing an extraintestinal infection, previous studies showed that it did not have the usual characteristics of an extraintestinal pathogenic E. coli. Instead, it belonged to phylogenetic group B1 and harbored few known virulence genes. To evaluate the pathogenic potential of strain EC121, an extensive genome sequencing and in vitro characterization of various pathogenicity-associated properties were performed. The genomic analysis showed that strain EC121 harbors more than 50 complete virulence genetic clusters. It also displays the capacity to adhere to a variety of epithelial cell lineages and invade T24 bladder cells, as well as the ability to form biofilms on abiotic surfaces, and survive the bactericidal serum complement activity. Additionally, EC121 was shown to be virulent in the Galleria mellonella model. Furthermore, EC121 is an MDR strain harboring 14 antimicrobial resistance genes, including blaCTX-M-2. Completing the scenario, it belongs to serotype O154:H25 and to sequence type 101-B1, which has been epidemiologically linked to extraintestinal infections as well as to antimicrobial resistance spread. This study with E. coli strain EC121 shows that clinical isolates considered opportunistic might be true pathogens that go underestimated. [ABSTRACT FROM AUTHOR]