Epidemiological study of human salmonellosis during 1991-1996 in southern Taiwan

Within a 6-year period from January 1991 to December 1996, 249 patients of salmonellosis admitted to Kaohsiung Medical College Hospital were enrolled for clinical and microbiological analysis. The number of patients increased by year from 1991 (14 patients) to 1996 (79 patients), especially in the case of nontyphoid salmonellosis. There were 57 different serotypes isolated during these period. Salmonella typhimurium was the most common clinical serotype of human origin in southern Taiwan, followed by S. choleraesuis, S. schwanzengrund, and S. derby. Fever (81.1%), diarrhea (68.9%), and anorexia (44.6%) were the most common manifestations of human salmonellosis. Relative bradycardia was a more important feature in S. typhi group (100%) than nontyphoid salmonellosis. Leukocytosis, especially lymphocytosis, was found especially in nontyphoid, but not in typhoid salmonellosis. Elevated liver function tests were found in the most severe patients, such as S. choleraesuis and S. typhi infections. Malignancy (8.8%), especially hematological malignancy (5.2%), gastrointestinal diseases (8.8%), and diabetes mellitus (6.4%) were the common underlying diseases. Case fatality rate of human salmonellosis was 8% (20/249), especially high in S. choleraesuis group. The severity of underlying diseases may be the major cause in S. choleraesuis group. There was no fatal case with typhoid fever. Very high resistance rate to commonly used antimicrobial agents in nontyphoid Salmonella was noted in southern Taiwan with overall rates of resistance to ampicillin, 67.9%, chloramphenicol, 66.7%, and TMP/SMZ, 42.2%. The emergence of ciprofloxacin-resistant and multiresistant strains was also a major therapeutic problem in this study.