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Sensitivity to the bactericidal effect of human serum of Proteus strains from clinical specimens
1Maulana Azad Medical College, New Delhi.
Abstract:
A total of 257 Proteus strains isolated from urinary tract infection, blood, wound and faeces were studied. Of the strains tested 31 (12 percent) were serum sensitive, 182 (71 percent) were serum resistant and the remaining 44 (17 percent) showed intermediate sensitivity to the pooled normal human serum (PNHS). Strains isolated from adult urines and blood cultures were significantly more sensitive than strains of faecal origin (p < 0.01). No significant difference was seen between strains from faeces and wounds.
Insights
Most Proteus strains causing infections are resistant to human serum. Urinary tract and blood isolates showed higher serum sensitivity compared to fecal strains, indicating potential differences in virulence factors.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Proteus species are opportunistic pathogens.
- Urinary tract infections (UTIs) and bloodstream infections are common clinical manifestations.
- Serum resistance is a key virulence factor for bacterial pathogens.
Purpose of the Study:
- To investigate the serum sensitivity of Proteus strains.
- To determine if serum sensitivity varies based on infection source.
Main Methods:
- Collected 257 Proteus strains from various clinical sources (UTI, blood, wound, feces).
- Assessed bacterial susceptibility to pooled normal human serum (PNHS).
- Statistical analysis (p < 0.01) to compare sensitivity across different isolation origins.
Main Results:
- 12% of strains were serum sensitive, 71% resistant, and 17% intermediate.
- Proteus strains from adult urine and blood cultures exhibited significantly higher serum sensitivity (p < 0.01) than fecal isolates.
- No significant difference in serum sensitivity was observed between fecal and wound isolates.
Conclusions:
- The majority of studied Proteus strains demonstrate resistance to human serum.
- Serum resistance may play a role in the pathogenesis of Proteus infections.
- Proteus strains from urinary tract and bloodstream infections are less serum resistant than those from fecal sources.