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Supplementary data to this article can be found online at: http://dx. doi.org/10.1016/j.ijfoodmicro.2017.04.009., In recent years, the microbiological safety of powdered infant formula has gained increasing attention due to the identification of contaminating C. sakazakii and its epidemiological link with life-threatening neonatal infections. Current intervention strategies have fallen short of ensuring the production of infant formula that is free from C. sakazakii. In this study, we describe the isolation and characterisation of three bacteriophages (phages) and their application as a phage cocktail to inhibit the growth of C. sakazakii in different brands of infant formula, while also assessing the phages ability to prevent biofilm formation. All three phages, isolated from slurry, possess a relatively broad host range, verified by their ability to infect across genera and species. When all three phages were combined and used as part of a phage cocktail, 73% coverage was obtained across all Cronobacter strains tested. Optimum thermo-tolerance and pH stability were determined between 4 °C37 °C, and pH 68, respectively, well within the normal range of application of infant formula. Genome sequencing and analysis revealed all the phages to be free from lysogenic properties, a trait which renders each favourable for phage therapy applications. As such, the combined-phage preparation (3 × 108 pfu/mL) was found to possess a strong bactericidal effect on C. sakazakii/C. sakazakii LUX cells ( 104 cfu/mL), resulting in a significant reduction in cell numbers, to below the limit of detection (, This work was funded by Technological Sector Research Strand III ref. CRS/07/CR03. Angela Back from MRI Kiel is acknowledged for technical assistance in preparations for electron microscopy. Hugo Oliveira and Rob Lavigne contributed to the genome sequencing analysis, supported by the KULeuven GOA (GOA/15/006) Grant Phagebiosystems., info:eu-repo/semantics/publishedVersion

In this study, a series of twenty-two ring-substituted 6-hydroxynaphthalene-2-carboxanilides was prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Mycobacterium tuberculosis H37Ra, Mycobacterium avium complex and M. avium subsp. paratuberculosis. Derivatives substituted by trifluoromethyl, bromo, methyl and methoxy moieties in C′ (3) and C′ (4) positions of the anilide ring showed 2-fold higher activity against M. tuberculosis than isoniazid and 4.5-fold higher activity against M. avium subsp. paratuberculosis than rifampicin. 6-Hydroxy- N -(2-methylphenyl)naphthalene-2-carboxamide had MIC = 29 μM against M. avium complex. A significant decrease of mycobacterial cell metabolism (viability of M. tuberculosis H37Ra) was observed using MTT assay. Screening of the cytotoxicity of the most effective antimycobacterial compounds was performed using the THP-1 cells, and no significant lethal effect was observed. The structure–activity relationships are discussed.

A series of styrylquinolines and quinolineamides based on the 8-hydroxyquinoline moiety were investigated as potential antimycobacterial agents. The lipophilicity of the compounds was measured using RP-HPLC and the tests of their activity against Mycobacterium kansasii, the M. avium complex, M. smegmatis, M. abscessus, M. tuberculosis and M. avium paratuberculosis was performed. Several of the compounds that were obtained appeared to be more effective than isoniazid and ciprofloxacin. The 5,7-dinitro-8-hydroxyquinoline derivative possessed the highest potency against M. abscessus and M. Smegmatis, which was about twice as effective as ciprofloxacin, while 2-(2-hydroxystyryl)-8-hydroxyquinoline-7-carboxylic acid appeared to be comparable with the standard drugs that are against the M. avium complex. The structure activity relationships are discussed.

A series of fifteen new N-alkoxyphenylanilides of 3-hydroxynaphthalene-2-carboxylic acid was prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Staphylococcus aureus, three methicillin-resistant S. aureus strains, Mycobacterium tuberculosis H37Ra and M. avium subsp. paratuberculosis. Some of the tested compounds showed antibacterial and antimycobacterial activity against the tested strains comparable with or higher than that of the standards ampicillin or rifampicin. 3-Hydroxy-N-(2-propoxyphenyl)naphthalene-2-carboxamide and N-[2-(but-2-yloxy)-phenyl]-3-hydroxynaphthalene-2-carboxamide had MIC = 12 µM against all methicillin-resistant S. aureus strains, thus their activity is 4-fold higher than that of ampicillin. The second mentioned compound as well as 3-hydroxy-N-[3-(prop-2-yloxy)phenyl]-naphthalene-2-carboxamide had MICs = 23 µM and 24 µM against M. tuberculosis respectively. N-[2-(But-2-yloxy)phenyl]-3-hydroxynaphthalene-2-carboxamide demonstrated higher activity against M. avium subsp. paratuberculosis than rifampicin. Screening of the cytotoxicity of the most effective antimycobacterial compounds was performed using THP-1 cells, and no significant lethal effect was observed for the most potent compounds. The compounds were additionally tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. N-(3-Ethoxyphenyl)-3-hydroxynaphthalene-2-carboxamide (IC50 = 4.5 µM) was the most active PET inhibitor. The structure-activity relationships are discussed.

In this study, a series of twenty-two ring-substituted 8-hydroxyquinoline-2-carboxanilides was prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Mycobacterium tuberculosis H37Ra, Mycobacterium avium complex and M. avium subsp. paratuberculosis. Some of the tested compounds showed the antimycobacterial activity against M. avium subsp. paratuberculosis comparable with or higher than that of rifampicin. 8-Hydroxy-N-[3-(trifluoromethyl)phenyl]- and 8-hydroxy-N-[4-(trifluoromethyl)phenyl]quinoline-2-carboxamide showed MIC=24 μM against all tested mycobacterial strains. 3-Methoxyphenyl- and 3-methylphenyl derivatives expressed MIC=27 or 29 μM also against all the tested strains. Their activity against M. avium subsp. paratuberculosis was 4-fold higher than that of rifampicin. 2-Bromophenyl- and 2-(trifluoromethyl)phenyl derivatives had MIC=23 or 24 μM against M. tuberculosis. A significant decrease of mycobacterial cell metabolism (viability of M. tuberculosis H37Ra) was observed using MTT assay. Screening of cytotoxicity of the compounds was performed using the THP-1 cells, and no significant lethal effect was observed up to tested concentration 30 μM. The structure-activity relationships are discussed.