SEROTYPE EPIDEMIOLOGY AND PATTERNS OF ANTIBIOTIC SUSCEPTIBILITIES OF SALMONELLAE ISOLATED IN HONG-KONG 1983-93

Objective. To study the serotype epidemiology and patterns of antibiot ic susceptibilities of salmonellae isolated in Kong Kong over an eleve n-year period. Methods. The laboratory information of 22 733 strains o f salmonellae isolated from diarrhoeae stool samples of 7 public hospi tals, 5 out-patient clinics and 2 public health laboratories and repor ted to the Salmonella surveillance system in Hong Kong from 1983 to 19 93 were analysed. Results. The yearly total number of isolates has rem ained steady, while an increasing proportion of cases occurred in the >25 years age group with a substantial decline in the <1 age group. Ma les were significantly more affected than females, particularly in tho se <15 years old. S. typhimurium and S. derby were the two most common ly isolated serotypes throughout the period. An outbreak of S. portsmo uth occurred which accounted for 15.3% of total isolates in that year. S. enteritidis has doubled in the last 2 years, while S. typhi has mo re than halved over the 11-year period. The S. enteritidis increase wa s seen mostly in the >25 age groups, with those <5 years little affect ed. Antibiotic susceptibility tests showed the typhoid and paratyphoid bacilli remained fully antibiotic sensitive, while non-typhoid non-pa ratyphoid isolates showed increasing resistance to ampicillin, chloram phenicol, tetracycline, and cotrimoxazole. Conclusions. Laboratory mon itoring of salmonella serotypes causing diarrhoeae and their antibioti c susceptibilities is essential as population movements and industrial activities increase in the southern parts of China.