Relationship between antibiotic resistance and invasion ofShigella sonnei strains

Background and Aim : Shigellosis is an important infectious disease that causes the death ofmany people every year, especially children under ۵ years old. The disease in children can occurwith mild to severe symptoms. Shigellosis manifests as diarrhea, abdominal pain and fever.Usually, the most common species of Shigella in developed countries is Shigella sonnei and indeveloping countries Shigella flexneri. Some multi-drug resistance (MDR) Shigella strains arehighly invasive, so there is a big challenge in treating patients infected with these strains.Therefore, we decided to investigate the relationship between the invasion of Shigella sonneistrains and their antibiotic resistance.Methods : In this study, we first selected ۵ strains of Shigella sonnei that were previously obtainedfrom the diarrhea of children with shigellosis. Then we investigate their antibiotic resistance usingKirby-Bauer disk diffusion method according to the Clinical and Laboratory Standards Institute(CLSI). The antimicrobial agents were as follows: ampicillin(AMP), azithromycin(AZM),ciprofloxacin(CIP), nalidixic acid(NA), Trimethoprimsulfamethoxazole(SXT), cefixime(CFM),cefotaxime(CTX), minocycline(MN), and levofloxacin(LEV). Finally, we performed theinvasiveness of the strains using the plaque formation assay test in Hela cells.Results : All five strains were MDR and all of them were able to form plaques in HeLa cells.Strain SS۲ showed the most invasiveness with the formation of ۲۰۲ plaques, but this strain wasresistant to only three antibiotics. Strain SS۳ had the highest resistance with resistance to ۷antibiotics, but with the formation of ۱۸ plaques, it had a low invasion power. The antibioticresistance profile and the number of plaques are as follows: SS۱: CFM, CTX, NA, AMP, SXT /۹۶ SS۲: NA, SXT, MN / ۲۰۲ SS۳: CFM, CTX, NA, AMP, SXT, MN, AZM / ۱۸ SS۴: NA, SXT,MN / ۱۵ SS۵: NA, SXT, MN / ۱۳Conclusion : No correlation was found between the invasion rate of Shigella sonnei strains andtheir antibiotic resistance profile.

کلیدواژه ها:

shigellosis ، Shigella sonnei ، plaque formation assay ، antibiotic resistance