Salmonella infection

More than 2200 serological variants of Salmonella have been described, of them more than 700 in humans. Salmonella typhimurium, Salmonella heidelberg, Salmonella enteritidis, Salmonella anatum, Salmonella derby, Salmonella london, Salmonella panama, Salmonella newport are most commonly encountered. Each year, 20-35% of the isolates are in Salmonella typhimurium.

Bacteriological examination of blood, feces and urine is the main method of diagnosing salmonella infection. Blood cultures give a positive result during the first 10 days of fever or if there is a relapse in 90% of patients, less than 30% after 3 weeks of the disease. Positive culture during the sowing of feces is received during the

from 10 days to 4-5 weeks in less than 50% of cases. The detection of salmonella in stool after 4 months after the disease and later( found in 3% of patients), indicates bacteriocarrier. In urine cultures, positive results are obtained for 2-3 weeks in 25% of patients, even if the culture of the blood is negative. The possibilities of bacteriological and serological methods for diagnosing salmonella infection are presented in Fig.

The antigenic structure of Salmonella is complex. It contains O- and H-Ar:

■ O-Ar is connected with the somatic substance of the cell, it is heat-stable, one of its components is Vi-Ar;

■ Н-Аг has a flagellar apparatus, thermolabile.

Differences in the structure of O-Ag allowed us to identify the serological groups of Salmonellae: A, B, C, D, E, etc. Based on differences in the structure of H-Ar, serological variants are established within each group. Among the serological diagnostic methods, until recently Vidal's reaction was widely used, and in recent years it has gradually lost its importance.

On the basis of the antigenic structure inherent in various types of Salmonella, O and H monodiagnosticums have been developed that allow the serological version of Salmonella to be established. Initially, the serum was tested in the RPHA with a complex preparation of erythrocyte salmonella-

weeks from the onset of infection

Fig. Possibilities of bacteriological and serological methods for diagnosing salmonella infection.

Weeks from the onset of infection

Fig. Possibilities of bacteriological and serological methods for diagnosing salmonella infection.

th diagnosticum containing O-Ar. Further, in the presence of agglutination with a complex diagnosticum, RPGA is given with preparations of groups A( 1,2,3), B( 1, 4, 12), C1( 6,7), C2( 6, 8), D( 1,9,12) and E( 3, 10).In Table. Antigenic characteristics of salmonella are presented, on the basis of which the serological variants of Salmonella are diagnosed.

Table Antigenic characteristic of salmonella

Table Antigenic characteristic of Salmonella

The titer of AT to H-Ar in the blood serum of patients with salmonella is very variable, it can give a nonspecific reaction with other infections;so its definition is not very useful for diagnosing the disease.

Vi-AT in the infectious process does not impart diagnostic and prognostic value. The situation is different with the detection of Vi-AT in bacterial carriers. Greater resistance of Vi-Ar-containing Salmonella to human defense mechanisms results in a longer-lasting carriage of these forms( Vi-forms) of salmonella, resulting in the detection of Vi-AT in the blood of such patients. Vi-AT is a direct proof of carriage.