**8. Antibiotic-resistant** *E. coli*

Antibiotic resistance genes have been generated in many gram-negative bacteria and *E. coli* is not an exception. These bacteria evolved different mechanisms that confer resistance to anti-biotics. *E. coli* can produce extended-spectrum beta-lactamase (ESBL) that makes the bacteria resistant to beta lactams (e.g., cephalosporins, monobactams, etc.). Carbapenemase-producing *E. coli* strains, on the other hand, have genes that confer carbapenem resistance (e.g., imipenem, ertapenem, and meropenem). ESBL producing *E. coli* are a rapidly evolving group of β-lactamases, produced by certain types of bacteria where *E. coli* are the major ones. These enzymes can break down the active ingredients by cleaving the beta-lactam ring of penicillin's and cephalosporin antibiotics, resulting in the inactivation of these


**Table 2.**

*Pathotypes of human IPEC [35].*

**12**


#### Escherichia coli*: An Overview of Main Characteristics DOI: http://dx.doi.org/10.5772/intechopen.105508*

*Source: EcL, APEC: avian pathogenic Escherichia coli, SEPEC: septicemic Escherichia coli, UPEC: uropathogenic Escherichia coli, EDEC: edema disease Escherichia coli.*

#### **Table 3.**

*Diseases associated with various intestinal pathogenic* E. coli *pathotypes in animals, [36].*



#### **Table 4.**

*Important ExPEC virulence-associated genes, their encoded proteins, function, and association with ExPEC pathotype [40].*

drugs, there are at least 200 different types of ESBL enzymes, increasingly isolated as causes of complicated UTIs and remain an important cause of failure of therapy with cephalosporin's and have serious infection control consequences. ESBL producing *Enterobacteriaceae* have been responsible for numerous outbreaks of infection throughout the globe and pose challenging infection control issues [42]. These organisms are associated with multidrug resistance causing a high rate of mortality and treatment failure [43].
