Computerized complex typing of Escherichia coli strains from different clinical materials

Area of Science:

• Microbiology
• Clinical Science
• Epidemiology

Background:

• Escherichia coli (E. coli) is a significant pathogen with diverse serogroups and virulence factors.
• Understanding the associations between E. coli characteristics and clinical outcomes is crucial for effective disease management.

Purpose of the Study:

• To investigate the relationships between E. coli serogroups, virulence markers, clinical specimens, patient demographics, and disease types.
• To explore correlations between animal pathogenicity, virulence factors, and clinical isolates.

Main Methods:

• Multivariate analysis of 3334 E. coli strains from various clinical materials.
• Characterization of serogroups, haemolysin (Hly) production, mannose resistant haemagglutinating activity for human erythrocytes (MRHA), colicinogenicity (Col), and K antigens (K1, K5).
• Correlation analysis with clinical data, patient age, nosocomial diseases, and animal pathogenicity tests (LD50, mouse lung toxicity).

Main Results:

• 50.2% of E. coli isolates belonged to 12 common serogroups.
• Significant associations were identified between specific serotypes and virulence markers (Hly, MRHA, Col, K1, K5).
• Correlations were found among clinical specimens, patient age, disease types, serogroups, and virulence markers, including links to meningitis, sepsis, and urinary tract infections (UTI).
• Highly virulent strains (LD50 < 10^6) were associated with serogroups O2, O6, O18ac, antigen K1, and CSF origin.
• Lack of virulence factors correlated with phage insensitivity, while K5 positivity showed sensitivity to specific phages.

Conclusions:

• Serotype, virulence markers, and clinical disease associations provide insights into E. coli pathogenicity.
• Animal pathogenicity tests offer valuable data for understanding disease mechanisms.
• Correlations between phage patterns and serogroups suggest epidemiological relatedness and strain virulence.