DISTRIBUTION AND MOBILITY OF THE TETRACYCLINE RESISTANCE DETERMINANT TETQ

We tested 34 American Type Culture Collection (ATCC) and 168 clinical bacterial isolates, from the human urogenital and oral tracts and stre ptococci isolated from cows with mastitis, for the presence of the tet Q gene using a polymerase chain reaction (PCR) assay and DNA-DNA hybri dization. The identities of PCR products were confirmed by Southern bl ot hybridization of whole-cell DNA. Eleven of the ATCC strains were po sitive for tetQ, including five Bacteroides spp., five Prevotella spp. and a single isolate of Mitsuokella multiacidus. Twenty-eight (29%) o f the 95 clinical Gram-negative isolates carried the tetQ gene, while eight (11%) of the 73 clinical Gram-positive isolates carried the tetQ gene. This is the first description of tetQ in Gram-positive species. All isolates except one Peptostreptococcus sp. carried tetQ integrate d into the chromosome. The tetQ gene could be transferred from Prevote lla bivia, Bacteroides ovatus, Bacteroides fragilis, Bacteroides vulga tus and Bacteroides distasonis into an Enterococcus faecalis recipient at frequencies of 10(-7)-10(-9) per recipient. In contrast, tetQ fail ed to transfer from two isolates of Prevotella intermedia, two isolate s of Porphyromonas gingivalis, one isolate of Mobiluncus curtisii and one isolate of Peptostreptococcus sp. The latter two are Gram-positive species. The PCR assay was used to screen 198 proteinase K-treated bi opsies of prostate, periprostate and bladder from 84 men with prostati tis. Thirty-four (40%) of the patients had one or more positive sample s, suggesting that the PCR assay could be of value in screening patien t material directly for the presence of bacteria.