Phage types of Salmonella enterica serovar Enteritidis isolated in South Africa from 1991-1995

Abstract

A total of 615 strains of Salmonella enterica serovar Enteritidis (SE), received from 1991-1995 at the Onderstepoort Veterinary Institute (OVI), were phage typed. Most SE isolates (54,7%) originated from poultry followed by humans (28 ,5 %) and poultry eggs (9,6 %). Phage type 34 was the most prevalent (40,5 %) of all isolates, followed by phage type 4 (33 ,8 %). Other phage types identified were 1, 1 b, 4a, 7, 7a, 9a, 14, 24, 24var and 35 (in total 2,4 % of isolates). Most isolates of SE were received from the Western Cape Province (47,4 %) and Gauteng (22,3 %). In poultry phage type 4 was dominant, but in humans, eggs, goats, ducks, sheep, pigs and rabbits, phage type 34 was the dominant type. It appeared as if the poultry-associated epidemic of SE in South Africa that occurred from 1991-1995 originated in the Western Cape Province during 1991 amongst poultry and then spread from there to humans and eggs and then to the rest of the country, where it emerged during 1993. Results indicate that phage type 34 was the dominant phage type from 1991-1993, but during 1994-1995 its presence declined. During this latter period the presence of phage type 4 increased. This may suggest that two smaller epidemics consisting of the two different phage types might have been responsible for the epidemic that occurred from 1991-1995.