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[Escherichia coli virulence factors causing peritonitis, appendicitis and other extraintestinal infections]
J Blanco1, J E Blanco, M P Alonso
1Departamento de Microbiología y Parasitología, Facultad de Veterinaria, Universidad de Santiago, Lugo.
Abstract:
Fifty-nine E. coli strains isolated from clinical cases of peritonitis, appendicitis, cholecystitis, wounds and respiratory infections as well as from other miscellaneous sources were investigated. A control group constituted by 475 E. coli strains isolated from the faeces of healthy individuals were also studied. E. coli O-grouped and investigated for production of cytotoxic necrotizing factor CNF1 and alpha-haemolysin (Hly), expression of P fimbriae and mannose-resistant (MRHA) and mannose-sensitive (MSHA) haemagglutination. Virulence factors significantly associated with extraintestinal strains were: production of CNF1 (19% versus 5%, p < 0.001), Hly (27% versus 9%; p < 0.001) and expression of MRHA (44% versus 16%; p < 0.001). The majority of extraintestinal strains (68% versus 36%; p < 0.001), in contrast with faecal E. coli, belonged to O serogroups frequently detected in uropathogenic and bacteraemic E. coli. These results suggest that E. coli causing different types of extraintestinal infections show similar virulence factors and belong to the same serogroups. However, between E. coli isolated from intraabdominal, wound and respiratory infections the number of strains with virulence factors was lower than in E. coli causing urinary tract infections and sepsis.
Insights
Extraintestinal pathogenic Escherichia coli (E. coli) strains share common virulence factors, including cytotoxic necrotizing factor 1 (CNF1) and alpha-hemolysin (Hly). These factors, along with specific O serogroups, are associated with E. coli causing infections beyond the urinary tract.
Area of Science:
- Microbiology
- Infectious Diseases
- Bacteriology
Background:
- Escherichia coli (E. coli) is a common bacterium that can cause various infections.
- Understanding the virulence factors of E. coli is crucial for diagnosing and treating infections.
Purpose of the Study:
- To investigate the virulence factors and O serogroups of E. coli strains isolated from diverse extraintestinal infections.
- To compare these factors with those of commensal E. coli from healthy individuals.
Main Methods:
- E. coli strains from clinical infections and healthy individuals were O-grouped.
- Production of cytotoxic necrotizing factor 1 (CNF1) and alpha-hemolysin (Hly) was assessed.
- Expression of P fimbriae and mannose-resistant (MRHA) and mannose-sensitive (MSHA) hemagglutination was analyzed.
Main Results:
- Extraintestinal E. coli strains showed significantly higher production of CNF1 (19% vs 5%), Hly (27% vs 9%), and MRHA (44% vs 16%) compared to fecal strains.
- A majority of extraintestinal strains (68%) belonged to O serogroups commonly found in uropathogenic and bacteremic E. coli.
- E. coli from intra-abdominal, wound, and respiratory infections had fewer virulence factors than those causing UTIs and sepsis.
Conclusions:
- E. coli causing various extraintestinal infections share similar virulence factors and O serogroups.
- These findings highlight common pathogenic mechanisms across different E. coli-related infections.
- Further research can focus on the specific roles of these virulence factors in different infection types.