Stability of probiotics with antibiotics via gastric tube by simple suspension method: An in vitro study

Data on the stability of probiotics with antibiotics delivered via gastric tube using the simple suspension method (SSM) are limited. Therefore, we investigated bacterial survivability in probiotics treated with antibiotics prepared by the SSM in vitro. Probiotics and antibiotics were suspended in 20 mL of sterilized hot water (55 °C) and then 1-mL of the suspensions were taken each at 10, 60, 120, 180 and 360 min. Thereafter, the samples were inoculated on 3 media and cultured at 37 °C for 24 h. Survival of probiotic strains was measured in colony-forming units. The growth of Clostridium butyricum did not change without antibiotics at all experimental times, but in the case of Enterococcus faecium tended to increase. On the other hand, the viable bacterial number of C. butyricum was decreased significantly by treatment with cefdinir, tosufloxacin, clarithromycin, or azithromycin, but was not altered by levofloxacin, minocycline, or vancomycin. The viable bacterial number of E. faecium was significantly decreased by treatment with tosufloxacin, levofloxacin, minocycline, vancomycin, or azithromycin, and was significantly increased by clarithromycin. In conclusion, our results suggest that the efficacy of probiotic therapies might be reduced by the SSM when specific antibiotics are used. Moreover, antibiotics might inhibit probiotic growth, although some probiotics are spore-forming and have high minimum inhibitory concentrations. Additionally, early administration of non-spore-forming bacteria might be desirable. Therefore, when patients are administered therapy combining probiotics and antibiotics by the SSM, we should consider the characteristics of the probiotics and the administration times.