Biotechnological Journal of Environmental Microbiology
Volume:1 Issue: 4, Winter 2022

In this root cause analysis, biofouling of membranes in the reverse osmosis (RO) unit of a Petrochemical Complex is studied. The overall cause of getting biofouling was found to be inappropriate water treatment of Pre-RO systems. More specifically, the undertreatment of water by sand filters, pressurized filters, and cartridges caused increased microbial contamination on RO membranes, leading to biofouling. Biodegradation of polymers is a mechanism by which the act of microorganisms will cause loss of mechanical integrity in such materials. It is important to understand the mechanism and look for ways by which such a mechanism can be controlled. The following were advised to control biofouling in the RO system of this Petrochemical complex 1. Chemical washing of sand filters as pressurized filters as well as RO membranes, 2. Application of UV or removal of chemical chlorination and installation of non-oxidizing biocides after chlorination,3. Replacement of Phosphorus-containing anticalins instead of non-phosphorus sealants,4. Application of superhydrophobic anti-microbial coatings on membranes

Listeria monocytogenes is the cause of listeriosis, which has many complications, especially in pregnant women. Due to the antibiotic resistance of this bacterium, many attempts have been made to introduce different medicinal compounds, including nanoparticles based on biological compounds. This research aimed to examine the mechanism of the effect of chitosan nanoparticles on L. monocytogenes in vivo (in the body of a living organism). The standard strain of L. monocytogenes (ATCC 7644) was prepared and analyzed in the Day Hospital Laboratory (Iran). The bacteria were examined based on biochemical tests. Then, the antibacterial activity of concentrations of 4.88 to 5000 µg/mL of chitosan nanoparticles against L. monocytogenes standard (ATCC 7644) was calculated with the investigated methods and the lowest inhibitory and bactericidal concentrations (MIC and MBC, respectively). The effects of different nanoparticle concentrations and ampicillin in mice infected with bacteria were also investigated. In infected mice, the therapeutic effect increased with increasing the nanoparticle concentration, and the concentration of 156.25 /mL was the most effective compared to other treatments. Also, ampicillin chitosan nanoparticles with a concentration of 39.06 g/mL had almost the same therapeutic effect. With the timely identification of listeria contamination in pregnant women and the proper use of chitosan nanoparticles instead of common drugs, a new solution can be found for the treatment of listeriosis.

Most of the pathogenic characteristics of Pseudomonas aeruginosa, a very well-known opportunist gram-negative bacteria, are modulated by its quorum sensing systems. Therefore, blocking quorum sensing pathways can be used as a strategy to confront P. aeruginosa. Non-steroidal anti-inflammatory drugs are among the most popular chemicals used as therapeutics against microbial infections. The chemical interaction space of diclofenac sodium, a well-known non-steroidal anti-inflammatory drug, has been investigated herein against two major receptors (LasI and LasR) involved in the quorum sensing system of P. aeruginosa. Optimized structures of ligands and receptors were subjected to molecular docking simulations, applying the AutoDock Vina plugin available in PyRx software. Results obtained from docking and non-covalent interaction space analyses revealed suitable binding energies against both LasI and LasR receptors. However, the binding energy of diclofenac sodium was more negative for LasR, showing its higher affinity for the LasR receptor. Finally, based on our results, it is suggested that diclofenac sodium has a good potential to bind both LasI and LasR receptors. This, in turn, can followed by the downregulation of some virulence factors genes. Therefore, diclofenac sodium can be considered a potent inhibitor of quorum sensing in P. aeruginosa.

Plant diseases have a significant impact on plants and their crop yields, causing extensive epidemics and recurrent damages that result in profound negative effects. Bacteria such as Erwinia, Pectobacterium, and Klebsiella have a very wide host range and can play a pathogenic role for a large number of ornamental and agricultural plants or even establish a symbiotic relationship with the plant. This group of bacteria that cause all kinds of plant diseases are able to affect seed tubers and the soil microbial community. The objective of this investigation was to identify and classify the distinct symbiotic pathogens associated with Trifolium resupinatum plants obtained from the Shahreza region located in the southern part of Isfahan, Iran. In this investigation, T. resupinatum specimens harboring nodular root structures were initially identified and subsequently retrieved from various locations in the southern region of Isfahan (Shahreza), before being transported to the laboratory. The Yeast Mannitol Agar (YMA) medium underwent a cultivation procedure, subsequent to which the bacterial samples were subjected to molecular identification utilizing morphological and biochemical tests. Additionally, the colony-PCR technique was employed to achieve definitive identification. This study examined the molecular features of three distinct species namely Erwinia chrysanthemi, Pectobacterium carotorum, and Klebsiella oxytoca. It was revealed that the former two species exhibited a symbiotic pathogenic relationship with the T. resupinatum plant, while the latter species posed a threat to human health as a pathogen.

The development of drug resistance, treatment ineffectiveness, and the occurrence of Pseudomonas aeruginosa infections are primarily attributed to biofilm formation and quorum sensing (QS)-dependent virulence factors. This study aimed to synthesize samarium oxide nanoparticles (Sm2O3NPs) using curcumin and evaluate their antimicrobial effects against P. aeruginosa isolated from different hospital wards. Based on TEM, XRD, and EDX analysis, the synthesized nanoparticles exhibited a cubic structure with an average size of 32.61 nm and a pure crystalline phase. The Sm2O3NPs exhibited notable antibacterial efficacy against P. aeruginosa strains. Based on the CV staining assay, sub-MIC of Sm2O3NPs inhibited the biofilm formation of P. aeruginosa strains by 16-69%. Additionally, the levels of pyocyanin in the NPs-treatment groups decreased by 29-58% compared to the control group. This research confirms the significant antibacterial potential of Sm2O3NPs, implying their potential utilization as an effective antibacterial agent against P. aeruginosa strains isolated from various hospital wards, after further characterization.

The rise of various strains of antibiotic-resistant bacteria has become [E1] one of the primary concerns. Therefore, efforts to utilize plant-derived drugs against drug-resistant bacteria have gained particular importance. This study aimed to investigate the antibacterial effects of the methanol extract of Myristica fragrans against Klebsiella pneumoniae and Acinetobacter baumannii isolates that produce broad-spectrum beta-lactamases. The plant extract was prepared using the maceration method. Then, the extract was filtered through Whatman filter paper, Grade 1, and concentrated and dried using a rotary evaporator system. Concentrations of 80, 40, 20, 10, 5, 2.5, 1.25, and 0.625 mg/mL of the extract were prepared in a 1:1 v/v mixture of dimethyl sulfoxide and methanol as solvents. Beta-lactamase-producing isolates were identified using the phenotypic method with the antibiotic's cefotaxime and the combination of cefotaxime/clavulanic acid. The agar well diffusion method assessed the antibacterial activity against the isolates. Based on the results, 33% of the Klebsiella isolates and 50% of the Acinetobacter isolates were found to produce beta-lactamase. All of the isolates were sensitive to the methanol extract of Myristica fragrans, with an average minimum inhibitory concentration of 10 and 5 mg/mL, respectively. According to the findings, it can be inferred that the Myristica fragrans extract can inhibit Klebsiella and Acinetobacter isolates in vitro. Therefore, with further research and identification of active compounds, it may be possible to utilize this extract as a potential alternative to antibiotics for treatment in the future.