In vitro adhesion and invasion of Salmonella enterica serovar Havana

Intestinal mucosal immune response in chickens following intraocular immunization with liposome-associated Salmonella enterica serovar enteritidis antigen

Induction of intestinal mucosal immune responses against Salmonella enterica serovar enteritidis was studied by immunizing chickens with liposome-associated antigen. An ultrasonicated whole cell extract of the bacteria was used for immunizing antigen. Intraocular immunization induced serum IgA, IgG and IgM responses. Also, significant IgA and IgG antibodies were detected in the intestinal tract. Immunization with antigen alone induced only IgG response in the intestine. Salmonella enteritidis-specific antibody-secreting lymphocytes were detected in the spleen and lamina propria of the intestinal tract of immunized chickens. Immunoglobulin (Ig) fractions extracted from intestines of immunized chickens inhibited the adherence of S. enteritidis to cultured HeLa cells. These results indicate that intraocular immunization with liposome-associated S. enteritidis elicits specific antibody-producing lymphocytes in the intestinal tract, and that Ig secreted in the intestine inhibits adherence of the bacteria to intestinal epithelial cells, suppressing the spread of bacterial infection in the host.

High incidence of extra-intestinal infections in a Salmonella Havana outbreak associated with alfalfa sprouts

OBJECTIVE

To determine a vehicle and point source for an outbreak of Salmonella Havana.

METHODS

The authors conducted a case-control study and traceback investigation of 14 residents of California and four from Arizona with onsets of illness from Apr 15, 1998, to June 15, 1998, and Salmonella Havana infections with identical PFGE patterns.

RESULTS

Seventeen of 18 patients were women. Seventeen were adults 20-89 years of age. Nine (50%) had diarrheal illness, 6 (33%) had urinary tract infections, 2 (11%) had sepsis, and one had an infected surgical wound after appendectomy. Four patients were hospitalized, and one died. Eating alfalfa sprouts was associated with S. Havana infection (OR = 10.0; 95% confidence interval 1.2, 83.1; P = 0.01).

CONCLUSIONS

This outbreak resulted in a high incidence of extra-intestinal infections, especially urinary tract infections, and high morbidity. Raw alfalfa sprouts, often considered a safe "heath food," can be a source of serious foodborne disease outbreaks.