Aetiological study on typhoid fever and paratyphoid fever in Ningbo City and relevant drug resistance monitoring and analysis

Objective The study was designed to understand the aetiological characteristic，distribution of bacteria types，and the sensitivity of bacteria to antibacterial drugs for typhoid fever and paratyphoid fever in Ningbo City in Spring of 2005．Methods The aquatic products on agricultural products market，such as tegiUarca granosa and oyster and etc．，were sampled for isolation and culture of pathogenic bacteria according to the methods in GB/T4789.4-2003，and the specimens of patients'blood and feces，as well as feces of the carriers，were taken for the same purpose but in compliance with GB/16001-1995．For the isolated strains，a biochemical identification was performed with all automatic VITEK analyzer，a typing conduced through serum agglutination test，and a test of drug sensitity done by the K-B method．Results There were total 185 strains isolated and collected．Including 3 strains of salmonella typhi and 182 strains of salmonella paratyphi A．The results of drug sensititivity test showed that the 185 strains were sensitive to cefoperazone，piperacillin，ceftriaxone，ceflazidime and tobramycin，with a sensitivity rate of 100％，relative sensitive to ampicillin，chloramphenicot，cefotaxime and norfloxacin，with a sensitivity rate above 80.0％，while the least sensitive to compound sulfonamides，with a sensitivity rate only 60.0％，in which 30.3％ (56/185)of strains showed a drug resistance．Conclusion The epidemic salmonella typhi，salmoneUa paratyphi and salmonella paratyphi A in local areas of Ningbo City in the spring of 2005 were predominant，with minor pathogen of salmoneUa typhi．The pathogenic bacteria show a good drug sensitivity to the third generation of cephalosporins，such as piperacillin，tobramycin and cefoperazone etc．They are preferred for the prevention and treatment of typhoid and paratyphoid at present．