Dissemination of mcr-1 and ß-lactamase genes among Pseudomonas aeruginosa: molecular characterization of MDR strains in broiler chicks and dead-in-shell chicks infections.

OBJECTIVES: Pseudomonas aeruginosa (P. aeruginosa) is one of the most serious pathogens implicated in antimicrobial resistance, and it has been identified as an ESKAPE along with other extremely significant multidrug resistance pathogens. The present study was carried out to explore prevalence, antibiotic susceptibility phenotypes, virulence-associated genes, integron (int1), colistin (mcr-1), and ß-lactamase resistance' genes (ESBls), as well as biofilm profiling of P. aeruginosa isolated from broiler chicks and dead in-shell chicks. DESIGN: A total of 300 samples from broiler chicks (n = 200) and dead in-shell chicks (n = 100) collected from different farms and hatcheries located at Mansoura, Dakahlia Governorate, Egypt were included in this study. Bacteriological examination was performed by cultivation of the samples on the surface of both Cetrimide and MacConkey's agar. Presumptive colonies were then subjected to biochemical tests and Polymerase Chain Reaction (PCR) targeting 16S rRNA. The recovered isolates were tested for the presence of three selected virulence-associated genes (lasB, toxA, and exoS). Furthermore, the retrieved isolates were subjected to phenotypic antimicrobial susceptibility testing by Kirby-Bauer disc diffusion method as well as phenotypic detection of ESBLs by both Double Disc Synergy Test (DDST) and the Phenotypic Confirmatory Disc Diffusion Test (PCDDT). P. aeruginosa isolates were then tested for the presence of antibiotic resistance genes (ARGs): int1, mcr-1, and ESBL genes (OXA-10, OXA-2, VEB-1, SHV, TEM, and CTX-M). Additionally, biofilm production was examined by the Tube Adherent method (TA) and Microtiter Plate assay (MTP). RESULTS: Fifty -five isolates were confirmed to be P. aeruginosa, including 35 isolates from broiler chicks and 20 isolates from dead in-shell chicks. The three tested virulence genes (lasB, toxA, and exoS) were detected in all isolates. Antibiogram results showed complete resistance against penicillin, amoxicillin, ceftriaxone, ceftazidime, streptomycin, erythromycin, spectinomycin, and doxycycline, while a higher sensitivity was observed against meropenem, imipenem, colistin sulfate, ciprofloxacin, and gentamicin. ESBL production was confirmed in 12 (21.8%) and 15 (27.3%) isolates by DDST and PCDDT, respectively. Antibiotic resistance genes (ARGs): int1, mcr-1, and ESBL genes (OXA-10, SHV, TEM, and CTX-M), were detected in 87.3%, 18.2%, 16.4%, 69.1%, 72.7%, and 54.5% of the examined isolates respectively, whereas no isolate harbored the OXA-2 or VEB-1 genes. Based on the results of both methods used for detection of biofilm formation, Kappa statistics [kappa 0.324] revealed a poor agreement between both methods. CONCLUSIONS: the emergence of mcr-1 and its coexistence with other resistance genes such as ß-lactamase genes, particularly blaOXA-10, for the first time in P. aeruginosa from young broiler chicks and dead in-shell chicks in Egypt pose a risk not only to the poultry industry but also to public health.

An Experimental and Computational Analysis of Plant Compounds from Whole Urtica dioica L. Plant's Essential Oil for Antioxidant and Antibacterial Activities.

As the Urtica dioica L. whole plant's essential oil has presented significant multiple activities, it was therefore evaluated using the GC-MS technique. This essential oil was investigated for its antioxidant, phytotoxic, and antibacterial activities in vitro. The GC-MS analysis data assisted in the identification of various constituents. The study of the essential oil of U. dioica showed potential antioxidant effects and antibacterial activity against the selected pathogens Escherichia coli -ATCC 9837 (E. coli), Bacillus subtilis-ATCC 6633 (B. subtilis), Staphylococcus aureus-ATCC6538 (S. aureus), Pseudomonas aeruginosa-ATCC 9027 (P. aeruginosa), and Salmonella typhi-ATCC 6539 (S. typhi). The library of 23 phytochemicals was docked by using MOE software, and three top virtual hits with peroxiredoxin protein [PDB ID: 1HD2] and potential target protein [PDB ID: 4TZK] were used; hence, the protein-ligand docking results estimated the best binding conformations and a significant correlation with the experimental analysis, in terms of the docking score and binding interactions with the key residues of the native active binding site. The essential oil in the silico pharmacokinetic profile explained the structure and activity relationships of the selected best hits, and their additional parameters provided insight for further clinical investigations. Therefore, it is concluded that the U. dioica essential oil could be a potent antioxidant and antibacterial agent for aromatherapy through its topical application, if further tested in a laboratory and validated.

Identification of a Potential Vaccine against Treponema pallidum Using Subtractive Proteomics and Reverse-Vaccinology Approaches.

Syphilis, a sexually transmitted infection, is a deadly disease caused by Treponema pallidum. It is a Gram-negative spirochete that can infect nearly every organ of the human body. It can be transmitted both sexually and perinatally. Since syphilis is the second most fatal sexually transmitted disease after AIDS, an efficient vaccine candidate is needed to establish long-term protection against infections by T. pallidum. This study used reverse-vaccinology-based immunoinformatic pathway subtractive proteomics to find the best antigenic proteins for multi-epitope vaccine production. Six essential virulent and antigenic proteins were identified, including the membrane lipoprotein TpN32 (UniProt ID: O07950), DNA translocase FtsK (UniProt ID: O83964), Protein Soj homolog (UniProt ID: O83296), site-determining protein (UniProt ID: F7IVD2), ABC transporter, ATP-binding protein (UniProt ID: O83930), and Sugar ABC superfamily ATP-binding cassette transporter, ABC protein (UniProt ID: O83782). We found that the multiepitope subunit vaccine consisting of 4 CTL, 4 HTL, and 11 B-cell epitopes mixed with the adjuvant TLR-2 agonist ESAT6 has potent antigenic characteristics and does not induce an allergic response. Before being docked at Toll-like receptors 2 and 4, the developed vaccine was modeled, improved, and validated. Docking studies revealed significant binding interactions, whereas molecular dynamics simulations demonstrated its stability. Furthermore, the immune system simulation indicated significant and long-lasting immunological responses. The vaccine was then reverse-transcribed into a DNA sequence and cloned into the pET28a (+) vector to validate translational activity as well as the microbial production process. The vaccine developed in this study requires further scientific consensus before it can be used against T. pallidum to confirm its safety and efficacy.