EFFECTS OF OXIDATIVE STRESS EXPOSURE ON MUCUS BINDING PROPERTIES AND ANTIBIOTIC RESISTANCE IN L. CASEI GROUP STRAINS
Comi G., Ginaldi F., Camprini L., Iacumin L.
Department of Food Science, University of Udine, via Sondrio 2, 33100 Udine, Italy
Adherence to mucus is one of the features required for a strain to be considerate as probiotic. Also antibiotic resistance is a fundamental character that needs to be investigated. In this study, 44 potentially probiotic strains, belonging to the species Lactobacillus casei, L. paracasei, and L. rhamnosus, were tested for their capability to bind mucin, as well as for their antibiotic resistance before and after being exposed to aerobic stress.
The bacterial cells capability to adhere to porcine gastric mucin type III was tested after a preliminary cell adaptation under anaerobic and respiratory conditions. In the first assay, some strains with interesting adhesion properties were found, but oxidative stress did not improve their binding features. Other strains, which did not show to have relevant binding capability when cultured under anaerobic conditions, increased their capability in binding mucin after the adaptation under respiratory conditions.
Results allowed the selection of strains showing good adherence to mucus. The oxidative stress seems not to be directly correlated to an increase in the binding mucin capability. The effect resulted strain specific, in fact for some strain a 2 fold increase in binding capacity was observed, conversely, some strains were not affected from the oxidative stress, and some others decreased their binding capability. On this bases, a selection of the more suitable strains, for exploitation in probiotic industry or in several food industry applications related to the production of probiotic-fermented food, can be made in order to proceed with further characterization studies.
As far as the antibiotic resistance is concerned, several changes in the behavior of the strain have been observed after oxidative stress exposure, but the effects were strain-specific and no general considerations can be deduced.
Keywords: Mucin, Adhesion, Antibiotic resistance, Aerobic stress, Probiotics
Comi G., Ginaldi F., Camprini L., Iacumin L. (2016). Effects of oxidative stress exposure on mucos binding properties and antibiotic resistance in L.Casei group strains. Conference Proceedings of IPC2016. Paper presented at the International Scientific Conference on Probiotics and Prebiotics, Budapest (p. 89.). IPC2016