BACTERIOLOGY OF NECROTIZING INFECTIONS OF SOFT-TISSUES

Background: Necrotizing infections of soft tissues (NIST) are being at tributed to a large variety of organisms, besides the originally descr ibed beta-haemolytic Streptococcus. A detailed bacteriological study o f these infections was thought worthwhile. Methods: A prospective stud y of 55 patients with NIST was carried out. Analysis of surface swabs and debrided tissue for aerobic and anaerobic bacteria and fungal infe ction was performed. A detailed bacteriological profile was obtained i n 50 patients. Results: A total of 257 isolates (167 aerobic, 90 anaer obic) was obtained. One to nine strains of bacteria were isolated from each patient. Aerobic bacteria alone were isolated in 26 patients whi le the remaining patients grew both aerobic and anaerobic bacteria. Fo rty-two patients had at least one Gram-positive bacterium while 40 had at least one Gram-negative bacterium. Staphylococcus aureus was the o rganism isolated most frequently (52%), followed by Bacteroides fragil is (40%) and anaerobic cocci (38%). Group A beta-haemolytic streptococ ci were isolated in 16%. Blood cultures were positive in only eight pa tients. Fungal cultures were positive in six patients. Aspergillus fum igatus was the commonest pathogen. Conclusions: Necrotizing infections of soft tissues are polymicrobial and no single bacterium is associat ed with a specific clinical entity. Importance should be placed on ear ly recognition and treatment of the disease rather than on isolation o f bacteria.