Investigations into the microbial contamination of toothbrushes

Used brushes (28 in toto) were assessed for microbial contamination. The micro-organisms removed from the toothbrush heads were plated onto a range of selective media. The total number of micro-organisms isolated per brush varied from 0 to 10(8) CFU. Staphylococci, coliforms, pseudomonads and yeasts were isolated from 64, 57, 28 and 39% of brushes, respectively. Identification tests on representative colonies indicated that media for streptococci, staphylococci, yeasts and pseudomonads were selecting for appropriate growth with > 90% efficiency. Of those tested on MacConkey agar eight from eleven colonies were oxidase negative, Gram-negative rods; the remainder were oxidase positive. No black pigmented obligate anaerobes were isolated. None of the seventeen colony types on Helicobacter selective agar proved to belong to that genus. Scanning electron microscopy of bristles revealed toothpaste debris, but micro-organisms were not evident.