Antimicrobial susceptibility patterns of infective Streptococci recovered from local and imported mozzarella cheese from different markets in Baghdad.

BACKGROUND

This research identified Streptococci spp. depending on culture, biochemistry, the Visual Information Technologies (VITEK) technique, ability to produce biofilms, and antibiotic resistance.

AIM: The goal of this study was to perform microbiological procedures to evaluate the qualitative qualities of mozzarella cheese against infective Streptococci using microbiological care.

METHODS

Sixty (60) mozzarella cheese samples were brought from diverse markets in Baghdad from October 2023 to December 2023 at the Zoonoses Research Unit and Veterinary Public Health Department, Veterinary Medicine College, University of Baghdad. Culture of samples on agar (MacConkey and blood) and aerobically incubated at 37°C for 48 hours. Gram staining purified colonies to notice Gram-positive cocci arranged in strings that were supposed to be Streptococcus species, and then sub cultured on nutrient agar for identification using the VITEK technique. The isolates were tested for their capacity to lyse human red blood cells by streaking blood agar and incubating at 37°C for 24 hours. Streptococcal isolates were streaked on a Congo-red medium. All isolates were inspected for antibiotic susceptibility using 15 common antibiotics via the disc diffusion method.

RESULTS

Isolates mozzarella cheese samples 8 (13.3%), these (eight) isolates include: (Streptococcus thoraltensis, Streptococcus sanguinis, Streptococcus cremoris, and Streptococcus alactolyticus. The susceptibility of S. thoraltensis, S. sanguinis, and S. alactolyticus was (26.6%), and S. cremoris (20%) to all antibiotics. Resistance of S. thoraltensis was (53%), S. sanguinis, S. alactolyticus were (66%), and S. cremoris was (73%) to all antibiotics. S. thoraltensis, S. cremoris, and S. alactolyticus were susceptible (75%) to Amikacin. S.sanguinis and S. cremoris were susceptible (50%) to Tigecycline. Streptococcus thoraltensis and S. alactolyticus were susceptible (50%) to Doxycycline. Streptococcus sanguinis and S. alactolyticus were susceptible (50%) to Ciprofloxacin. Streptococcus thoraltensis and S. sanguinis were susceptible (50%) to Azithromycin. Streptococcus sanguinis was susceptible (25%) to vancomycin. Streptococcus alactolyticus was susceptible (25%) to Streptomycin. Streptococcus thoraltensis was susceptible (25%) to Amoxicillin and Clavulanic acid. S. cremoris was susceptible (25%) to Penicillin. All isolates were 100% resistant to imipenem, lincomycin, meropenem, methicillin, and chloramphenicol.

CONCLUSION

Analysis of mozzarella cheese samples identified four predominant Streptococcus species and their antibiotic activity.