The bacterium Helicobacter pylori infects more than 50% of the world population and causes several gastroduodenal diseases, including gastric cancer. Nevertheless, we still need to explore some protein interactions that may be involved in pathogenesis. MreB, an actin homolog, showed some special characteristics in previous studies, indicating that it could have different functions. Protein functions could be realized via protein-protein interactions. In the present study, the MreB protein from H. pylori 26695 fused with two tags 10×His and GST in tandem was overexpressed and purified from Escherchia coli. The purified recombinant protein was used to perform a pull-down assay with H. pylori 26695 cell lysate. The pulled-down proteins were identified by mass spectrometry (MALDI-TOF), in which the known important proteins related to morphogenesis were absent but several proteins related to pathogenesis process were observed. The bacterial two-hybrid system was further used to evaluate the protein interactions and showed that new interactions of MreB respectively with VacA, UreB, HydB, HylB and AddA were confirmed but the interaction MreB-MreC was not validated. These results indicated that the protein MreB in H. pylori has a distinct interactome, does not participate in cell morphogenesis via MreB-MreC but could be related to pathogenesis.

Background: Stenotrophomonas species are multi-resistant bacteria with ability to cause opportunistic infections. Objective: We isolated 45 Stenotrophomonas species from soil, sewage and the clinic with the aim of investigating their susceptibility to commonly used antimicrobial agents. Methodology: The identities of isolates were confirmed with 16S rRNA gene sequence and MALDI-TOF analysis. Anti-mi- crobial resistance, biofilm production and clonal diversity were also evaluated. The minimum inhibitory concentration technique as described by Clinical & Laboratory Standards Institute: CLSI Guidelines (CLSI) was employed for the evaluation of isolate susceptibility to antibiotics. Result: Forty-five Stenotrophomonas species which include 36 environmental strains and 9 clinical strains of S. maltophilia were considered in this study. 32 (88.9 %) environmental strains were identified to be S. maltophilia, 2 (5.6 %) were Stenotrophomonas nitritireducens, and 2 (5.6 %) cluster as Stenotrophomonas spp. Stenotrophomonas isolates were resistant to at least six of the antibiotics tested, including Trimethoprim/Sulfamethoxazole (SXT). Conclusion: Environmental isolates from this study were resistant to SXT which is commonly used for the treatment of S. maltophilia infections. This informs the need for good public hygiene as the environment could be a reservoir of multi-resistant bacteria. It also buttresses the importance of surveillance study in the management of bacterial resistance. Keywords: Stenotrophomonas; environmental; biochemical characterization; clonal diversity; anti-microbial susceptibility.

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is a Deltaproteobacteria, ubiquitous, Gramnegative, uniflagellate, highly motile, preys on Gram-negative bacteria, recently reported predation on Gram-positive bacteria. It belongs to the BALOs group (Bdellovibrio and-like -organisms ). bdellovibrio exovores it moves quickly using its flagellum, adhering to the outer membrane, secreting enzymes and mechanical movements consumes the prey. b. bacteriovorus invades the periplasm forming a bdelloplast, where it replicates by multiple fission. The factors involved in predation are the flagellum, mobilization, lytic enzymes, interaction genes "hit locus" bd0108 and bd0109, prey range, etc. The objective was to characterize phenotypic and molecular isolates of Bdellovibrio spp. in Mexico. Pathogenic bacteria of clinical interest were used as prey, and samples of water, soil, and animal feces, to isolate predatory bacteria, were confronted in order to observe lytic activity. Sequences of the 16S rRNA gene were used to amplify by PCR for the genus Bdellovibrio, sequences from the family Bdellovibrionaceae. Eightysix positive isolates for BALOs were obtained, cell lysis of the prey bacteria was observed, a prey range was performed, measuring the lytic activity (prey-predator).

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