Antibacterial Activity of a novel Lectin produced by bee honey Bifidobacterium adolescentis against Multidrug Resistant Salmonella typhi

Lectins are glycoproteins attached to carbohydrate noncovalently. probiotic bacterial lectins have immunomodulatory effect, antibacterial and antifungal effect, supportingconsortium and maintaining healthy coordination among microbes or between microbes and host. Colonization of Bifidobacterium in gastro-intestine of host are essential, the attachment of Bifidobacterium to the mucosa of host was mediated by lectins. This study aimed to isolation of B. adolescentis from bee honey, detection, extraction and purification of lectin produced by B. adolescentis and investigation of the antimicrobial activity of crude and purified B. adolescentis lectin. Sealed honeybee colonies were obtained for B. adolescentis isolation directly from honey. Honeybee colonies were provided from honeybee colonies from Hella city- Iraq during May 2017. Six isolates of B. adolescentis isolated were obtained by cultivation of bee honey on De Man, Rogosa and Sharpe (MRS) and were identified by API32CH. Two methods were performed for lectin screening detection: semi-quantitative detection and quantitative hemagglutination assay. The results revealed that, human erythrocytes AB+ and O+ and sheep erythrocytes gave hemagglutination activities with all B. adolescentis but it was higher against O+ human erythrocytes. Lectin was extracted and purified and the protein content of lectin was estimated and was 0.13 mg/ ml. Thirteen isolates of Salmonella typhi isolated from stool samples obtained from patients admitted to Al-Escan Hospital / Baghdad-Iraq and were diagnosed by VITEK-2 system then tested for their susceptibility to antibiotics via disc diffusion method. Salmonella typhi appeared to be multidrug resistant. Crude and purified B. adolescentis lectin were subjected to antibacterial activity against S. typhi pathogen. The results indicated that B. adolescentis lectin at bothconcentrations, 32 and 64 μg/ml possesses significant antibacterial activity against multidrug resistant S. typhi as compared with control (P<0.05). The antibacterial activity of crude and purified lectin in concentration 64 μg/ml was higher than antibacterial activity of concentration 32 μg/ml(P<0.05). Furthermore, the antimicrobial activity of purified lectin was significantly higher than crude lectin, P<0.05. In conclusions B. adolescentis found to be one of the components of bee honey. Bee honey B. adolescentis isolates produced a lectin but they varied in production amounts. Lectin hemagglutinate human blood groups AB+ and O+ and sheep erythrocytes but it was higher active against O+ human erythrocytes. The crude and purified lectin had antibacterial activity against multidrug resistance S. typhi. Bifidobacterium adolescentis lectin at 32 and 64 μg/ml possesses significant antibacterial activity against multidrug resistant S. typhi as compared with control but antibacterial activity of crude and purified lectin at 64 μg/ml was higher than that of concentration 32 μg/ml. Moreover, antimicrobial activity of purified lectin was significantly higher than crude lectin.

Keywords:

lectin , antibacterial activity , B. adolescentis , Salmonella typhi , bee honey