An analysis of blood culture isolates from 7 South African teaching hospital centres

The data on blood culture isolates for 1983 and January - July 1984 reported by the Antibiotic Study Group of South Africa have been analysed to determine national and regional prevalences of different micro-organisms and resistance to certain antibiotics. Although there are significant differences in isolation frequencies between the various centres, overall the five most frequent isolates are Staphylococcus aureus (1983 - 15%; 1984 - 14%), Escherichia coli (13%), Klebsiella spp. (11%; 10%), Streptococcus pneumoniae (9%), and Salmonella typhi (7%; 13%). Staph. aureus ranks first in most centres for 1983 but is displaced in some in 1984 by enteric Gram-negative bacilli. In Durban S. typhi is the most common isolate for the entire period. Methicillin resistance among Staph. aureus is common (approximately 30% overall), especially in the Transvaal. Gentamicin resistance among certain Gram-negative bacilli is a problem in many centres and is especially disturbing in the case of Klebsiella spp., of which over 30% of total isolates are resistant. Ampicillin resistance for Haemophilus influenzae varies from nil to over 30% in different centres, and penicillin-resistant pneumococci are still encountered (nil to over 10%).