Spectinomycin remains a useful reserve option for
therapy of
gonorrhea. The emergence of multidrug-resistant Neisseria gonorrhoeae strains with decreased susceptibility to
cefixime and to
ceftriaxone makes it the only medicine still effective for treatment of
gonorrhea infection in analogous cases. However, adoption of
spectinomycin as a routinely used
drug of choice was soon followed by reports of
spectinomycin resistance. The main molecular mechanism of
spectinomycin resistance in N. gonorrhoeae was C1192T substitution in
16S rRNA genes. Here we reported a Thr-24→Pro mutation in
ribosomal protein S5 (RPS5) found in
spectinomycin resistant clinical N. gonorrhoeae strain, which carried no changes in
16S rRNA. In a series of experiments, the transfer of rpsE gene allele encoding the mutant RPS5 to the recipient N. gonorrhoeae strains was analyzed. The relatively high rate of transformation [ca. 10(-5) colony-forming units (CFUs)] indicates the possibility of spread of spectinonycin resistance within gonococcal population due to the horizontal gene transfer (HGT).