Microbiological characteristics of Weeksella virosa (formerly CDC group IIf) isolated from the human genitourinary tract.

Weeksella virosa (formerly CDC group IIf) is a nonsaccharolytic, oxidase- and catalase-positive, gram-negative rod which is unable to grow on MacConkey agar. At 48 h of incubation on blood or chocolate agar, the colonies present a characteristic appearance: intensely mucoid, adherent, and cream colored as a result of the production of a nondiffusible yellow pigment. This microorganism has been isolated predominantly from the female genitourinary tract, which indicates the opportunity for sexual transmission. We present the microbiological study of three strains of W. virosa identified in a study of 707 female genital samples, representing an incidence of 0.42%. At the same time, we analyzed the principal biochemical tests used in the identification of this microorganism and the susceptibilities of the organism to the different antimicrobial agents assayed.