TABLE 1.
Validated virulence factors in APEC.
| Name/Description | Functions | Present in ExPEC | References |
| Adhesins | |||
| Type I fimbriae | Colonization, biofilm formation | APEC, NMEC, SEPEC UPEC, | Ewers et al., 2007 |
| P fimbriae | Colonization, stimulate of cytokines production, | APEC, UPEC, SEPEC, | Kariyawasam and Nolan, 2009 |
| Flagella (FliC) | Colonization, biofilm formation | APEC, UPEC | Dziva et al., 2013 |
| Curli | Colonization, biofilm formation | APEC, UPEC, SEPEC | La Ragione et al., 2000 |
| Temperature sensitive hemagglutinin (Tsh) | Adherence | APEC, UPEC, NMEC | Kostakioti and Stathopoulos, 2004 |
| Iron acquisition | |||
| Aerobactin | Siderophore, acquisition of iron | APEC, UPEC | Gao et al., 2015a |
| Salmochelin | Siderophore receptor, use of Fe irons | APEC, NMEC, SEPEC, UPEC | Caza et al., 2008 |
| SitABC | Transportation of Fe, Mn | APEC, UPEC | Sabri et al., 2008 |
| Antiphagocytic activity/serum resistance | |||
| Transfer protein | Inhibition of the classical pathway of complement activity | APEC, NMEC, SEPEC | Sarowska et al., 2019 |
| Capsule | Resistance to human alpha-defensin 5 | APEC, NMEC, UPEC | Thomassin et al., 2013 |
| LPS | Reduce the environmental acidity | APEC | Yu et al., 2015 |
| Increased serum survival (Iss) | Protect against phagocytosis | APEC, NMEC, SEPEC | Nolan et al., 2003 |
| Toxins | |||
| Vacuolating autotransporter toxin | Induce vacuolization of host cell | APEC, UPEC | Ewers et al., 2004 |
| Serin protease autotransporter | Epithelium colonization, mucins degradation | APEC, UPEC | Pokharel et al., 2019 |
| Invasins | |||
| IbeA | Invasion, resistance to oxidative stress | APEC, NMEC, SEPEC | Cortes et al., 2008 |
| IbeB | Invasion | APEC, NMEC | Wang et al., 2012 |
| GimB | Adherence and invasion | APEC, NMEC, UPEC | Matter et al., 2015 |
| Two component regulatory systems | |||
| CpxA/CpxR | Fitness, virulence | APEC, UPEC | Yamamoto and Ishihama, 2006 |
| BarA/UvrY | Biofilm formation, persistence | APEC, UPEC | Herren et al., 2006 |
| RstA/RstB | Acid resistance, intracellular survival | APEC | Gao et al., 2015b |
| PhoB/PhoR | Intracellular survival | APEC | Bertrand et al., 2010 |
| Secretion systems | |||
| E. coli type III secretion system 2 (ETT2) | Virulence, intracellular survival | APEC, NMEC, UPEC | Wang et al., 2016a; Fu et al., 2021; Li et al., 2022; Xue et al., 2022; Yin et al., 2022 |
| Type VI secretion system | Interbacterial competition, stress sensing, virulence | APEC, NMEC | Hachani et al., 2016 |