Hafida Zahir

1. Although staphylococci are an integral part of the human skin microbiota, they are among the leading causes of nosocomial infections worldwide.[1] These opportunistic pathogens are capable of ca...

The drinking water distribution system (DWDS) is often threatened by the dangerous threat of biofilms as these intricate microbial consortia aggressively colonize pipe surfaces and act as reservoirs for pathogens which accelerate the infrastructure decay and degrade the organoleptic quality. Their resistance to conventional disinfection which includes chlorine, and their powerful regenerative capacity make eradication strategies ineffective. Environmental variables that govern biofilm proliferation include temperature, nutrient availability, water chemistry, and hydrodynamics, as well as the pipe material. The safeguarding of the water quality needs to be transformed by integrated and multi-barrier strategies. This necessitates also the implementation of advanced solutions like novel antibacterial surfaces, next-generation biocides, and stringent nutrient limitation to interrupt the resilience of biofilm and to protect public health.

Multidrug-resistant bacteria represent a serious public health concern due to their reduced susceptibility to multiple antibiotics and their capacity to form biofilms, which complicates treatment and contributes to persistent infections. Total phenolic compounds and flavonoids were quantified...

Electrostatic charge significantly influences microorganism–surface interactions, including viral adhesion and transmission. While bacterial surface charges are well characterized using electrophoretic mobility and X-ray photoelectron spectroscopy (XPS), similar studies for viruses are limited. This work bridges the gap by estimating the negative surface charge of the Phi6 bacteriophage using XPS data. A novel approach is applied, combining chemical functionalities derived from XPS with a system of equations to quantify surface polysaccharides, proteins, hydrocarbons, and negatively charged groups (RCOO⁻ and R₂PO₄⁻). The results indicate a predominance of proteins on the viral surface and a pH-dependent negative charge: phosphate groups dominate at low pH (1–3), while both groups contribute equally at pH 4–9. These findings provide a deeper understanding of virus–surface interactions and underscore the importance of pH in modulating viral surface charge. This method, which surpasses traditional electrophoretic mobility techniques, offers new perspectives for studying viral adhesion and developing improved antiviral materials and disinfection strategies.

Physicochemical properties of the bacterial surface are involved in several interfacial phenomena such as microbial adhesion. Ecology Soil salinity is a crucial parameter for the distribution of Streptomyces. The objective of this study is to investigate the impact of NaCl on the hydrophobicity...

Research into the formation of Pseudomonas savastanoi biofilms on olive trees is essential to prevent infections that induce tumor formation and damage tree health. To prevent the development of P. savastanoi biofilms, it is crucial to comprehend the factors influencing its adhesive behaviour....

This innovative study focused on the threat posed by Pseudomonas savastanoi, the causal agent of olive tuberculosis. This pathogen induces the formation of tumors on the bark and leaves of olive trees, adversely affecting the health of the tree and olive oil production. The objective was to assess the effectiveness of a coating based on olive mill wastewater (OMWW) as a biocontrol agent. Specifically, the study examined its influence on the initial adhesion of P. savastanoi on various olive tree surfaces, including bark and the upper and lower leaf surfaces. The physicochemical characteristics of these surfaces were analyzed by evaluating the contact angle between the bacterial strain and the supports, both before and after treatment with OMWW. The results revealed significant variations in initial bacterial adhesion before treatment, with the lower leaf surface (LSL) showing higher adhesion capacity. However, after treatment with OMWW, initial adhesion decreased by up to 95 %, demonstrating the effectiveness of the coating. Furthermore, OMWW treatment influenced the physicochemical characteristics of all supports, particularly the electron donor character, which significantly reduced initial bacterial adhesion. This underscores the crucial role that surface physicochemical properties play in bacterial interactions, both before and after treatment. These findings provide promising insights for the development of sustainable biocontrol methods aimed at mitigating the impact of olive tuberculosis on the olive oil industry.

Olive oil, extracted from olive fruits (Olea europaea), is renowned for its distinctive flavour, nutritional richness and health benefits. The aim of this comparative study is to analyze olive oil from several TADLA perimeter units, including Province of AZILAL, FQUIH BEN SALAH, BENI MELLAL, ZAOUIT CHEIKH, and BRADIA. The oil under investigation was extracted from olives of the Moroccan Picholine variety, by a discontinuous system including grinding, pressing and decanting. Significant variations were found at the values of the studied parameters. The results of our study showed that Olive oil from FBS and BM are classified as an extra virgin olive. However, olive oils from ZC, BR and AZ are classified as virgin olive oil. Sample from FQUIH BEN SALAH province had the lowest Free Fatty Acids (FFA) and peroxide values 0.236% oleic acid and 3.434 méqO2/Kg respectively. While the highest FFA value found was the olive oil obtained from AZILAL (1.084% Oléic Acid) and the highest Peroxide value was obtained in the sample from BRADIA (8.108 méq O2/Kg). E232, E270 and delta K values of all samples were under the limit fixed by IOC for virgin olive oil. Polyphenols content of ZAOUIT CHEIKH, FQUIH BEN SALAH and BRADIA oils are relatively high with values equal to 1.347, 1.082, and 1.141mg GA/100ml extract respectively. DPPH test showed that ZAOUIT CHEIKH oil had the greater antioxidant capacity.