MULTISTRAIN OUTBREAK OF CHANCROID IN SAN-FRANCISCO, 1989-1991

Restriction fragment length polymorphism (RFLP) and plasmid analyses w ere used to evaluate an outbreak of Haemophilus ducreyi in San Francis co. Fifty-four cases of culture-confirmed chancroid occurred between M ay 1989 and May 1991. Of these, 46 (96%) were in men and 35 (65%) were in blacks; the median age of patients was 34 years. Among the 32 isol ates submitted for RFLP and plasmid analyses, six different HindIII RF LP patterns were identified. Two RFLP types were found in patients who had recently traveled to Los Angeles, Korea, or El Salvador. Four RFL P types appeared to be acquired locally and were more common among bla cks (P = .002), in patients with a history of a sexually transmitted d isease (P = .01), and in those who used drugs or exchanged drugs or mo ney for sex (P = .08). The use of RFLP analysis confirmed that this ou tbreak was associated with multiple strains of H. ducreyi and allowed for the identification of risk factors for locally acquired chancroid.