2^nd International Conference on Vaccine Research and Immunology December 02-03, 2019 Paris, France

Xuenan Xuan has obtained his PhD at the University of Tokyo in 1991, and currently he is the Director General of National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Japan. He has published more than 300 papers in the field of Parasitology and Virology.

In this study, the protective effect of recombinant Babesia microti apical membrane protein 1 (rBmAMA1) and rhoptry neck protein 2 (rBmRON2) against B. microti infection was evaluated in a hamster model. The genes encoding the predicted domains I and II of BmAMA1 and the gene encoding the predicted transmembrane regions 2 and 3 of BmRON2 were expressed as his fusion recombinant proteins in Escherichia coli. Three groups with five hamsters in each group were immunized with rBmAMA1, rBmRON2 and rBmAMA1þ rBmRON2, and then challenged with B. microti. The result showed that only the group immunized with rBmAMA1þ rBmRON2 exhibited protection against B. microti challenge infection, characterized by significant decreased of parasitemia and higher hematocrit values from day’s six-10 post challenge infection. However, there was no significant difference in the groups immunized with rBmAMA1 or rBmRON2 alone. The absence of a significant difference in the total amount of antibodies against rBmAMA1 and rBmRON2 between the groups immunized with single and combined proteins. This result indicates that the protection cannot be solely attributed to the quantity of antibodies produced, but also to their ability to target important epitopes from both antigens. These results suggest that combined immunization with rBmAMA1 and rBmRON2 is a promising strategy against B. microti infection.

Sara M Atmani has completed her PhD and Postdoctoral studies from Houari Boumediene University of Sciences and Technology in Algeria, Laboratory of Cellular and Molecular Biology. Her research interests are linked to Bacterial Virulence and Antimicrobial Resistance.

The study aimed to investigate the antimicrobial resistance and involved mechanisms in uropathogenic Enterobacteriaceae strains isolated from patients in Algeria. The study concerned 41 non repetitive strains isolated between from 2018-2019. Bacterial identification by the API 20E system showed Escherichia coli (n=18) as a dominant uropathogen followed by Klebsiella pneumoniae (n=13), Enterobacter cloacae (n=6), Providencia rettgeri, Morganella morganii, Proteus mirabilis and Proteus vulgaris (n=1). Antibiotic susceptibility by the disc diffusion method showed a high prevalence of acquired resistance to β-lactams (78%) which was extended to 3rd and 4th generation cephalosporins in 21.9% strains (all positive by the double-disc synergy test). Among non-beta-lactams, resistance rates were of 46.3% (aminoglycosides), 22% (sulfamethoxasole-trimethoprim) and 17.1% (quinolones/fluoroquinolones). A rate of 21.9% of isolates were MDR phenotype (4 E. cloacae, 3 K. pneumoniae, M. morganii and P. mirabilis), all but one were ESBL-producers. PCR screening showed the presence of blaSHV (31.7%, all K. pneumoniae); blaTEM (46.3%); blaCTX-M in ESBL-producers; plasmid-mediated quinolone resistance determinants identified as qnrB (24.4%), aac(6’)-Ib-cr (14.6%) and qnrS (9.7%); aminoglycoside-modifying enzyme genes aac(6’)-Ib (24%) and aac(3)-II (24%); sulfamethoxasole-trimethoprim resistance genes identified as sul2 (83.3%), sul1 (50%), sul3 (8.3%), dfrA5 (66.6%), dfrA12 (25%), dfrA1 (16.7%) and dfrA7 (8.33%). Class 1 integrons were detected in 31.7% of isolates. The study showed a high prevalence of acquired resistance to antibiotics among uropathogenic Enterobacteriaceae. The presence of MDR ESBL strains is an important clinical concern. A constant monitoring of antimicrobial resistance is required to ensure therapeutic efficacy and prevent the emergence and spread of multidrug resistance.