Chloramphenicol resistant typhoid fever.

We report a patient with typhoid fever caused by a strain of Salmonella typhi which was resistant to chloramphenicol. This is the first documentation of chloramphenicol resistant Salmonella typhi in Sri Lanka.

Ileal perforation in typhoid: bacteriological and immunological findings.

In typhoid perforation patients, Salmonella typhi was isolated from blood in 4%, ileal contents in 23%, peritoneal pus in 13% and from mesenteric lymph nodes in 71%. While isolation of S. typhi was made from patients with less than 4 days of chloramphenicol therapy, cultures were negative from these sites after 5 days of therapy; however, S. typhi appeared to remain viable in the lymph nodes even after such therapy. All isolates of S. typhi were sensitive to chloramphenicol. Significant SAT titers (0 > or = 1/240) were obtained in only 7/21 (33%) of patients. The perforated group had lower geometric mean titers (0-1/138; H-1/46), when compared to matched patients with uncomplicated typhoid fever (0-1/476; H-1/148). This difference was significant (0- p < 0.005; H- p < 0.0025). The two groups (uncomplicated and perforated) showed no significant difference in total serum IgG, IgM and IgA or isohemagglutinin levels, indicating that the apparent hyporeactivity was not due to a generalized humoral immunodeficiency. Mesenteric lymph node histology showed hyporeactivity in both the T cell and B cell zones. These findings are discussed with the suggestion that S. typhi-specific host immunological hyporeactivity could be an explanation for these observations and a basis for the pathogenesis of perforation. Aerobic cultures of the peritoneal pus gave 39 isolates from 25 patients; the predominant isolates were Escherichia coli (24) and Klebsiella pneumoniae (12). On no occasion was S. typhi the predominant isolate. Gentamicin and kanamycin were the only two antibiotics which were consistently effective in vitro against the aerobic isolates from peritoneal pus.

An evaluation of the SAT in the diagnosis of typhoid.

Salmonella typhi O and H antibody titres were determined by the Standard Agglutination Test (SAT) in 85 patients with bacteriologically proven typhoid, 102 patients with non-typhoidal febrile illnesses (control group 1), and 170 healthy subjects (control group 2). An O antibody titre of 1/120 occurred in 93% of patients with typhoid fever (7% false negatives), and in 17% and 12% control groups 1 and 2 respectively. An H antibody titre of 1/120 was found only in 64% of patients with typhoid (false negatives in 36%). At titres other than 1/120, the proportion of false negatives or false positives increased ie. the sensitivity and specificity decreased. Although the SAT continues to be used in Sri Lanka as the main diagnostic test in typhoid, the sensitivity and specificity of this test fall below the requirements of a useful diagnostic test.