Antibiotic resistance of lactobacilli and bifidobacteria isolated from dairy products and drugs

Probiotics - living microorganisms whose administration has a positive effect on health - are currently widely used, in particular for the prevention and treatment of diarrhea associated with antibiotics; however, the question of the ability of these microorganisms to survive when taken simultaneously with antibacterial drugs remains open.

In a microbiological study by M.R. D'Aimmo et al. (Italy), studied the sensitivity of probiotic bacteria which are part of a number of dairy products and commercial drugs. The identification of microorganisms was carried out by the method of electrophoresis of soluble proteins, as well as by multiple PCR with primers specific to the genus and to the species. The study of the sensitivity of the isolates was carried out by determining the minimum inhibitory concentration (MIC) for 24 antibacterial drugs widely used by the method of micro-dilutions in broth.

A total of 34 strains were identified as probiotics (representatives of Bifidobacterium spp. And Lactobacillus spp.), And 21 strains of microorganisms used to ferment dairy products ( leaven). All the isolated bifidobacteria were Bifidobacterium animalis subspecies lactis, with the exception of one strain Bifidobacterium longum. Among the lactobacillus strains obtained, Lactobacillus acidophilus, Lactobacillus casei and Lactobacillus delbrueckii subsp. bulgaricus. It should be noted that the strains isolated from probiotics do not always correspond to those indicated on the label. For fermentation, Streptococcus thermophilus was most often used.

All strains tested during the study were sensitive to ampicillin, bacitracin, clindamycin, dicloxacillin, erythromycin, novobiocin, penicillin, rifampicin (MPC90 = 0.01-4 μg / ml) and resistant to aztreonam, cycloserine, kanamycin acid, polymides and spectinomycin (IPC90 = 64 - greater than 1000 μg / ml). The susceptibility of the isolates to cephalotin, chloramphenicol, gentamicin, lincomycin, metronidazole, neomycin, paramycin, streptomycin, tetracycline and vancomycin varied by species.

Based on the study, it can be assumed that the feasibility of using probiotics (especially lactobacilli and bifidobacteria) simultaneously with most antibiotics used in clinical practice is questionable, since probiotic microorganisms are sensitive many antimicrobial agents.