TY - JOUR AU - Ammar, Ahmed M AU - Abd El-Aziz, Norhan K AU - Gharib, Ahlam A AU - Ahmed, Hanaa K AU - Lameay, Amira E PY - 2016/08/31 Y2 - 2024/03/29 TI - Mutations of domain V in 23S ribosomal RNA of macrolide-resistant Mycoplasma gallisepticum isolates in Egypt JF - The Journal of Infection in Developing Countries JA - J Infect Dev Ctries VL - 10 IS - 08 SE - Original Articles DO - 10.3855/jidc.7850 UR - https://jidc.org/index.php/journal/article/view/27580325 SP - 807-813 AB - <p class="SmallText">Introduction: Avian mycoplasmas impose a significant economic burden to the poultry industry. In recent years, macrolide-resistant <em>Mycoplasma gallisepticum</em> have occasionally been encountered in Egypt.</p> <p class="SmallText">Methodology: This study was designed to document the involvement of macrolide-resistant <em>M. gallisepticum </em>in respiratory organs of chickens suffering respiratory problems. Concurrently, an exhaustive molecular characterization of the intrinsic resistance of recovered isolates to macrolides was done.</p> <p class="SmallText">Results: Of 120 chickens showing respiratory problems, 14 (11.67%) <em>M. gallisepticum</em> were isolated and genetically identified; 8 of them were recovered from air sacs, 4 from lungs, and 2 from tracheas. Broth microdilution of all <em>M.</em> <em>gallisepticum</em> isolates showed various degrees of minimum inhibitory concentrations (MICs) against macrolides: erythromycin (0.25–32 µg/mL), tylosin (0.0625–4 µg/mL), and tiamulin (0.031–2 µg/mL). Nucleotide sequencing of domain V (peptidyl transferase region) of the 23S rRNA gene of macrolide-resistant<em> M. gallisepticum</em> isolates revealed transition mutations at positions 2068 and 2069 (corresponding to 2058 and 2059 in <em>Escherichia coli </em>numbering) in an isolate and at position 2067 (corresponding to 2057 in <em>E. coli </em>numbering) in three isolates as hot spots for macrolide resistance. Surprisingly, a transversion mutation at position 2621 (corresponding to 2611 in <em>E. coli </em>numbering) was reported in one of the recovered isolates as a first report.</p> <p class="SmallText">Conclusion: Generation of new mutations is evidence for persistence of <em>M. gallisepticum</em> despite macrolide treatment. Periodic surveys to monitor for the possible appearance of resistant strains are recommended.</p> ER -