Aflatoxin B1 Occurrence in Children under the Age of Five's Food Products and Aflatoxin M1 Exposure Assessment and Risk Characterization of Arab Infants through Consumption of Infant Powdered Formula: A Lebanese Experience.

Aflatoxin M1 (AFM1) is a salient metabolite that can be used to assess Aflatoxin B1 (AFB1) exposure in humans and animals. The carcinogenic potency of AFB1 and AFM1 was severely reported. The aims of this study were (1) to survey the contamination level of AFM1 in the most traded infant powdered formula brands (IPF) (n = 42) along with the AFB1 level in under 5's children food brands (biscuits, cornflakes, and cereals) (n = 42) and (2) to assess the estimated daily intake (EDI), the hazard quotient (HQ) and the margin of exposure (MOE) of AFM1 among infants (0-12 months) in Lebanon. All of the samples were analyzed using ELISA technique. AFB1 was below detection limit in all of the children's food brands samples. Out of 42 IPF samples 9.5% were AFM1-positive in the range of 29.54-140.16 ng/L and exceeded the maximum tolerable limit (MTL) set by the European commission (25 ng/kg). The overall average contamination level was 5.72 ± 0.014 ng/L. The EDI of AMF1 for male was in the range of 0.37-0.78 ng/kg/b.w./day and 0.40-0.87 ng/kg/b.w./day for females. Similarly, the HQ calculation resulted in an average of 3.05 for males and 3.28 for females. MOE calculations were far lower from 10,000 in both genders which indicates a high risk of genotoxicity and carcinogenicity. Our findings show that AFM1's EDI, HQ and MOE scored high among Lebanese infants. As infants consume more IPF relative to their body weight, the persistence of IPF with high AFM1 levels threatens their health. Thus, infant's exposure risk to AFM1 in IPF should be a continuous focus of attention.

Innovative SPE-LC-MS/MS technique for the assessment of 63 pharmaceuticals and the detection of antibiotic-resistant-bacteria: A case study natural water sources in Lebanon.

A powerful analytical method for simultaneous determination of 63 pharmaceuticals and some metabolites in aqueous samples has been developed. The list of compounds amenable to the methods includes different therapeutic classes belonging to antibiotics, stimulants, antidepressants, mucolytics, and antiparasites. The method involves concentration and clean up by an offline solid phase extraction SPE followed by liquid chromatography coupled to tandem mass spectrometry (LC-ESI-MS/MS). The recovery of the target compounds from water samples was most efficient on Waters Oasis HLB SPE cartridge, while acetonitrile/water (60/40) was shown to be the most suitable solvent for desorbing the compounds from SPE. In addition, acidification of samples prior to SPE was optimized to enhance the recovery of the compounds. In terms of method validation, the recoveries of analytes ranged from 68% to 134%. Repeatability and intermediate precision were <11% and 14%, respectively. The method detection limits ranged from 2.3ngL-1 to 94.3ngL-1. An optimized method was applied in a monitoring program to study the occurrence of pharmaceuticals to more than hundred samples collected from rivers, lakes, fountains, and wells overall Lebanon from April to June 2016. Caffeine, erythromycin and its degradation forms, were the most frequently detected compounds at levels reaching >10,000ngL-1 and 2000ngL-1, respectively. Moreover, bacterial analysis showed that the samples were contaminated by Escherichia coli (23%), intestinal Enterococcus (48%) and Pseudomonas aeruginosa (27%). Therefore, in order to evaluate if a correlation exists between finding antibiotics in water samples and the development of resistant-bacteria, an antimicrobial susceptibility test was conducted to the identified isolates using disk diffusion method. Multiple-antibiotic-resistant strains in both intestinal Enterococcus and E. coli were evident in many water samples, while P. aeruginosa was resistant to only one studied antibiotic.

VBNC Legionella pneumophila cells are still able to produce virulence proteins.

Legionella pneumophila is the agent responsible for legionellosis. Numerous bacteria, including L. pneumophila, can enter into a viable but not culturable (VBNC) state under unfavorable environmental conditions. In this state, cells are unable to form colonies on standard medium but are still alive. Here we show that VBNC L. pneumophila cells, obtained by monochloramine treatment, were still able to synthesize proteins, some of which are involved in virulence. Protein synthesis was measured using (35)S-labeling and the proteomes of VBNC and culturable cells then compared. This analysis allowed the identification of nine proteins that were accumulated in the VBNC state. Among them, four were involved in virulence, i.e., the macrophage infectivity potentiator protein, the hypothetical protein lpl2247, the ClpP protease proteolytic subunit and the 27 kDa outer membrane protein. Others, i.e., the enoyl reductase, the electron transfer flavoprotein (alpha and beta subunits), the 50S ribosomal proteins (L1 and L25) are involved in metabolic and energy production pathways. However, resuscitation experiments performed with Acanthamoeba castellanii failed, suggesting that the accumulation of virulence factors by VBNC cells is not sufficient to maintain their virulence.

Involvement of minerals in adherence of Legionella pneumophila to surfaces.

Legionella pneumophila is the causative agent of 90 % of Legionnaires' disease cases. This bacterium lives naturally in fresh water and can colonize biofilms, which play an important role in the protection of Legionella against environmental stress factors. Relationship between the presence of minerals in water and Legionella adherence to surfaces is not well-known. In this study, we studied influence of minerals on bacterial adherence. For the first time, to our knowledge, this report shows that calcium and magnesium in a less extent, enhances the adherence of Legionella to surfaces compared to the bacteria behavior in distilled water. Treatment with proteinase K of live cells showed that surface proteins do not seem to play a crucial role in bacteria adherence to surfaces. Our results represent a first step in understanding effect of ions on Legionella adherence to surfaces. Such field of research could be helpful to better understand biofilm colonization by this bacterium to improve Legionella risk management in water networks.

Passage through Tetrahymena tropicalis enhances the resistance to stress and the infectivity of Legionella pneumophila.

Legionella pneumophila is a gram-negative bacterium prevalent in fresh water which accidentally infects humans and is responsible for the disease called legionellosis. Intracellular growth of L. pneumophila in Tetrahymena is inconsistent; in the species Tetrahymena tropicalis stationary-phase forms (SPFs) of L. pneumophila differentiate into mature intracellular forms (MIFs) without apparent bacterial replication and are expelled from the ciliate as pellets containing numerous MIFS. In the present work, we tested the impact of L. pneumophila passage through T. tropicalis. We observed that MIFs released from T. tropicalis are more resistant to various stresses than SPFs. Under our conditions, MIFs harboured a higher gentamicin resistance, maintained even after 3 months as pellets. Long-term survival essays revealed that MIFs survived better in a nutrient-poor environment than SFPs, as a reduction of only about 3 logs was observed after 4 months in the MIF population, whereas no cultivable SPFs were detected after 3 months in the same medium, corresponding to a loss of about 7 logs. We have also observed that MIFs are significantly more infectious in human pneumocyte cells compared with SPFs. These results strongly suggest a potential role of ciliates in increasing the risk of legionellosis.