---------------------------------------------------

 Diarrheagenic and uropathogenic E. coli have been divided into 6 pathotypes depending on their characteristics, virulence factors and their mode of action (Malema et al., 2018; Rivas et al., 2015):

Shiga-toxin producing E. coli (STEC) or Enterohemorrhagic E. coli (EAEC)

A group of foodborne bacteria responsible for a wide variety of infections, from mild diarrhea to serious dysentery cases like hemorrhagic colitis (HUC). The most common serotypes of EHEC/STEC related to human infections are O24, O45, O103, O111, O121, O145 and O157. The unique characteristic of EHEC isolates is that they’re capable of producing shiga-toxins — a toxin. made of one active A subunit linked with one B5 subunit responsible for binding the toxin with glycolipid receptors on the surface of the target cells which induces systemic absorption (figure 1). Shiga-toxins prevent the production of proteins by removing the residual adenine from rRNA 28S for ribosome 60S (Melton-Celsa, 2014; Gould et al., 2013; Moxley et al., 2020).

Figure 1 Enterohemorrhagic E. coli (EHEC) (Vilalta, 2018)

Enteropathogenic E. coli (EPEC) EPEC

is a known pathotype of E. coli capable of causing diarrhea and also cause tissue damage to the intestine that is known as attaching and effacing lesions (AE) which results in the destruction of normal microvilli architecture (figure 2).

Incapable of producing shiga-toxin, heat-labile (LT) and heat-stable (ST) enterotoxins. Classified into typical and atypical EPEC, typical Enteropathogenic E. coli (tEPEC) that cause diarrhea to humans have a plasmid called E. coli adherence factor (EAF) plasmid with the operon bfp which encodes bundle-forming pilus (BFP), while atypical EPEC (aEPEC) strains don’t have the aforementioned operon (Mare et al., 2021).

Figure 2 Enteropathogenic E. coli (EPEC) (Vilalta, 2018)

Enterotoxigenic E. coli (ETEC)

ETEC strains distinguish themselves from other E. coli pathotypes by their ability to produce colonization factors (CF) and enterotoxins: LT and ST. ETEC is the main cause of diarrhea in children in developing countries and anyone traveling to these areas. ETEC produce two kinds of enterotoxins: Heat-labile (LT) and heat-stable (ST). The main symptom of ETEC infection is watery diarrhea caused by the loss of ions and huge amount of water because of the enterotoxins which cause issues in the transmembrane channels in the intestinal epithelium (figure 3) (Buuck et al., 2020; Fleckenstein, 2010).

Figure 3 Enterotoxingenic E. coli (ETEC) (Vilalta, 2018).

Enteroinvasive E. coli (EIEC)

The pathogenic causative agent of dysentery in humans and especially in developing countries. Dysentery occurs because of enteroinvasive E. coli’s (EIEC) invasion and entrance into the intestinal cells causing their destruction. The bacterium attaches to the mucus layer of the large intestine by a process called endocytosis and may spread through one cell to the next (figure 4). Eneteroinvasive E. coli serotype O96:H19 was found to be the causative agent of an outbreak in Sweden recently (Michelacci et al., 2020; Lagerqvist et al., 2020).

Figure 4 Enteroinvasive E. coli (EIEC) (Vilalta, 2018).

Enteroaggregative E. coli (EAEC)

Distinguished by the AA pattern it shows on epithelial cells on tissue cultures. AA pattern is described as a “stacked-brick” on top of the surface of cells in epithelial tissues culture (figure 5). Diarrhea caused by EAEC is watery with mucus present, blood may or may not be present, stomach pain, low-grade fever and vomiting. In 2011, a large outbreak of a certain hybrid strain happened in Germany resulting in more than 4,300 cases of diarrhea and 50 deaths (Ellis et al., 2020).

Fig 5. Enteroaggregative E. coli (EAEC) (Vilalta, 2018).

Diffusely Adhering E. coli (DAEC)

 DAEC causes unique changes on epithelial cells, resulting in diarrhea and epithelia damage which may lead to other intestinal diseases. DAEC encompasses a group of E. coli strains that have genes encoding for Afa/Dr adhesions that are capable of causing diarrhea in humans (figure 6). Capable of infecting children, and it’s considered the second most common cause of death in children under 5 years of age (Omolajaiye et al., 2020).

Fig 6. Diffusely Adhering E. coli (DAEC) (Vilalta, 2018).

References
-------------

Buuck, S., Smith, K., Fowler, R. C., Cebelinski, E., Lappi, V., Boxrud, D., and Medus, C. (2020). Epidemiology of Enterotoxigenic Escherichia coli infection in Minnesota, 2016 – 2017. Epidemiology and Infection, 148(e206), 1–7. DOI: 10.1017/S0950268820001934

Ellis, S. J., Crossman, L. C., McGrath, C. J., Chattaway, M. A., Holken, J. M., Brett, B., Bundy, L., Kay, G. L., Wain, J., and Schuller, S. (2020). Identification and characterisation of enteroaggregative Escherichia coli subtypes associated with human disease. Scientific Reports, 10(7475), 1–12. DOI: 10.1038/s41598-020 64424-3

Fleckenstein, J.M., Hardwidge, P.R., Munson, G.P., Rasko, D.A., Sommerfelt, H. and Steinsland, H., (2010). Molecular mechanisms of enterotoxigenic Escherichia coli infection. Microbes and infection, 12(2), pp.89-98.

Gould, L.H., Mody, R.K., Ong, K.L., Clogher, P., Cronquist, A.B., Garman, K.N., Lathrop, S., Medus, C., Spina, N.L., Webb, T.H. and White, P.L. (2013). Increased recognition of non-O157 Shiga toxin– producing Escherichia coli infections in the United States during 2000– 2010: epidemiologic features and comparison with E. coli O157 infections. Foodborne pathogens and disease, 10(5), pp.453-460.

Lagerqvist, N., Löf, E., Enkirch, T., Nilsson, P., Roth, A., and Jernberg, C. (2020). Outbreak of gastroenteritis highlighting the diagnostic and epidemiological challenges of enteroinvasive Escherichia coli, County of Halland, Sweden, November 2017. Euro Surveill, 25(9), 1–8. DOI: 10.2807/1560 7917.ES.2020.25.9.1900466

Malema, M. S., Abia, A. L. K., Tandlich, R., Zuma, B., Kahinda, J-M. M., Ubomba Jaswa, E. (2018). Antibiotic-Resistant Pathogenic Escherichia coli Isolated from Rooftop Rainwater-Harvesting Tanks in the Eastern Cape, South Africa. Int J Environ Res. Public Health. 15(892): 1-14.

Mare, A. D., Ciurea, C. N., Toma, F., Man, A., Tudor, B., and Moldovan, V. (2021). Enteropathogenic Escherichia coli — A Summary of the Literature. Gastroenterology Insights, 12, 28–40. DOI: 10.3390/gastroent12010004

Melton-Celsa, A.R. (2014). Shiga toxin (Stx) classification, structure, and function. Microbiology spectrum, 2(2).

Michelacci, V., Tozzoli, R., Arancia, S., D’Angelo, A., Boni, A., Knijn, A., Prosseda, G., Greig, D. R., Jenkins, C., Camou, T., Sirok, A., Navarro, A., Schelotto, F., Varela, G., and Silva, R. M. (2020). Tracing Back the Evolutionary Route of Enteroinvasive Escherichia coli (EIEC) and Shigella Through the Example of the Highly Pathogenic O96:H19 EIEC Clone. Frontiers in Cellular and Infection Microbiology, 10(260), 1–13. DOI: 10.3389/fcimb.2020.00260

Moxley, R.A., Bargar, T.W., Kachman, S.D., Baker, D.R., Francis, D.H. (2020). Intimate Attachment of Escherichia coli O157:H7 to Urinary Bladder Epithelium in the Gnotobiotic Piglet Model. Microorganisms, 8(2): 263. DOI: 10.3390/microorganisms8020263

Omolajaiye, S. A., Afolabi, K. O., and Iweriebor, B. C. (2020). Pathotyping and Antibiotic Resistance Profiling of Escherichia coli Isolates from Children with  Acute Diarrhea in Amatole District Municipality of Eastern Cape , South Africa. BioMed Research International.

Rivas, L., Mellor, G., Gobius, K., and Fegan, N. (2015). Detection and Typing Strategies for Pathogenic Escherichia coli. Springer, New York, USA. DOI: 10.1007/978-1-4939-2346-5

Vilalta, E. G. (2018). Interplay of virulence, antibiotic resistance and epidemiology in Escherichia coli clinical isolates. PhD thesis. Universitat de Barcelona, Barcelona, Spain.

مواضيع ذات صلة

بكتريا Borrelia burgdorferi

المرض المبقع Pinta

مرض بجل Bejel

الدمامل furuncles والجمرة الكبيرة carbuncles وخراجات الجلد

NOCARDIOSIS

العنقوديات الذهبية Staphylococcus aureus

المسبحيات الرئوية Streptococcus pneumonia

Food Spoilage by lactic acid bacteria

مجموعة المسبحيات Streptococcus pyrogenes) A)

المسبحيات Streptococci

اللاهوائيات المكونة للسبورات المطثيات Clostridium انموذجا

الاصابات بالبكتريا اللاهوائية