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Background Misuse of antibiotics in veterinary medicine has the potential to generate residues in animal derived products, which could contributing to the development of an important health risk either through the exposure to antibiotic residues or the transfer of antibiotic resistance among foodborne pathogens as well. Tetracycline (TE) and eptomycin (ST) are commonly used as antibiotics in the Egyptian animal husbandry. The objective of this study, quick detection of TE and ST in fresh local beef tissue samples using radioimmunoassay Charm II technique, isolation and identification of relevant highly resistant bacterial strains. In addition to investigating the effect of gamma radiation on the susceptibility of such resistant strains to TE and ST. Results Tetracycline (TE) was detected in all collected samples, while ST was detected in 38.46% (5/13) and 87.5% (7/8) of meat and liver samples, respectively. Fifty-one bacterial isolates were isolated from the tested samples, among them, the highest resistant isolates to TE or ST were identified as Streptococcus thoraltensis, Proteus mirabilis (2 isolates) and E. coli (3 isolates). Among them, the highest D10-values in phosphate buffer; 0.807 and 0.480; kGy were recorded with S. thoraltensis and E. coli no.3, respectively. Such values increased to record 0.840 and 0.549 kGy, respectively after artificial inoculation into meat, indicating increased resistance to gamma radiation. Gamma radiation at dose 3 kGy increased the susceptibility of S. thoraltensis up to 50% to TE and ST, while the sensitivity of E. coli no.3 reached up 56% to both antibiotics at the same dose. Conclusions High prevalence of TE in all fresh collected tissue samples suggests an extensively use of TE as antimicrobial in conventional beef production as compared to ST in the Egyptian cows’ husbandry. Moreover, irradiation of food from animal origin by gamma radiation could potentially provide protection against resistant strains. In spite of limited samples used in this study, our data could raise the concerns of public health professionals about a withdrawal period before animals slaughtering, and address the importance of gamma radiation to minimize the hazards of foodborne resistant bacteria.

Streptococcus thoraltensis was first isolated from pigs and rabbits. Later, isolation from human oral and nasal cavities and from throat and oropharynx was documented. S. thoraltensis was isolated from patients with periodontitis, tonsillopharyngitis, and chorioamnionitis suggesting a possible pathological role in human infections. All S. thoraltensis isolates of animal and human origins were sensitive to vancomycin.Standard microbiological identification methods, biochemical analysis, and antibiotic susceptibility testing using disk diffusion and E methods were used. Automatic species identification and antibiotic susceptibility testing were carried out using the Vitek 2 compact system. Molecular analysis of vancomycin resistance gene was carried out using a PCR with specific primers for vanA.We report a healthy young female adult, aged 19 years, with history of exposure to pet rabbit who had nasal colonization with S. thoraltensis. Identification of S. thoraltensis was based on traditional microbiological methods (culture, Gram stain, and biochemical tests), and the Vitek 2 compact system with 97% confidence rate. Antibiotic susceptibility testing of the isolate indicated resistance to most antibiotics, including penicillins, cephalosporins, methicillin, and glycopeptides. The minimal inhibitory concentration for vancomycin and teicoplanin was exceptionally high (256 μg/mL). Molecular analysis indicated the absence of vanA gene in S. thoraltensis.We report for the first time the isolation of a fully vancomycin-resistant S. thoraltensis independent of vanA from a healthy human anterior nasal cavity. The pathological role of this newly identified organism with an exceptionally rare resistance pattern in human infections is yet to be identified.

Streptococcus thoraltensis has mainly been reported to cause infections in animals. Its clinical significance as a human pathogen has not yet been fully elucidated and needs further investigation. We describe here a case of bacteremia attributed to S. thoraltensis in a 55-year-old female patient admitted to our department due to fever of unknown origin. To the best of our knowledge, this is the first reported case of S. thoraltensis bacteremia in a human and the first reported case of S. thoraltensis as a cause of fever of unknown origin in human.

Streptococcus thoraltensis, Genus Streptococcus sensu stricto, is a rare species of streptococci that has been very rarely reported to cause infection in humans. It is isolated from the sows and is found in the intestinal tract of pigs. We describe here a case of S. thoraltensis bacteremia in a postpartum patient with pneumonia.

Context: The genus Streptococcus consists of more than 65 species. The taxonomic classification of these members is not well-defined. Among the viridans group streptococci (VGS), there are major taxonomic changes by the addition of many new species; whereas, most of the new strains are of animal origin and only a few have been reported to be isolated from humans. Rare and unusual species of VGS such as Streptococcus thoraltensis, S. pluranimalium and S. hyointestinalis are normally associated with different animals. Their isolation from human being is not yet reported. Aim: To find out the rare and unusual species of viridans group streptococci from human oral cavity. Settings and Design: A case-controlled study carried out at hospital-based dental services in a tertiary care hospital. Materials and Methods: Subgingival plaque samples of the tooth were collected from 80 patients (34 with periodontitis and 46 without periodontitis) undergoing tooth extraction. Cultures were subcultured onto special media such as Tryptone Soya blood Agar supplemented with strepto supplement and Mutans-Sanguis Agar. Identification of strains and antimicrobial susceptibilities were measured as minimum inhibitory concentration using Vitek 2 (BioMerieux, Paris, France) automated system. Results: We have identified three strains of VGS - S. thoraltensis, S. pluranimalium and S. hyointestinalis from subgingival plaque samples from patients with periodontitis. S. thoraltensis and S. pluranimalium were found to be resistant to most of the antibiotics. Conclusions: To the best of our knowledge, this is the first report of isolation of these rare and unusual strains from the human oral cavity.