Evaluation of Bactericidal Action of Serum Collected from Paratyphoid Patients and Normal Human against Salmonella Paratyphi

Abstract

A comparative study of susceptibility of clinical isolates of Salmonella Paratyphi to bactericidal action of
S. Paratyphi infected human serum and uninfected human serum was investigated. Bactericidal action of S. Paratyphi
infected human serum and uninfected human serum was assessed after incubating the bacterial suspension of S. Paratyphi
with 40% of both infected and unifected human serum at various incubation times. Eight samples of S. Paratyphi infected
serum from the patients diagnosed with paratyphoid fever were used. The investigation found that the serum killed S.
Paratyphi both by classical and alternative pathways. Anti- S. Paratyphi antibodies for the bactericidal action of serum
were examined by the assessment of bactericidal activity of non-immune normal human serum. Significant killing of S.
Paratyphi by S. Paratyphi infected serum was investigated and the serum mediated killing was increased by increasing
the incubation time. The mean growth declines gradually as the incubation time was increased. No noteworthy serum
mediated killing was observed for normal human serum and inactivated (heat induced) S. Paratyphi infected serum.