New Insights into the Effect of Origanum Extracts on the Gene Expression Profiles of Multidrug-resistant Isolates of Pseudomonas aeruginosa Retrieved from Oreochromis niloticus

Abstract

Pseudomoniasis has become a serious threat not only as a disease but also for the ensuing emergence of antibiotic-resistant bacteria. Thus, a total of 180 Oreochromis niloticus and water samples were collected from three intensive farms located in Ismailia Governorate for physicochemical and biological analysis. All retrieved isolates were tested for the presence of the P. aeruginosa oprL gene and for their sensitivity to commercial antimicrobial agents. Isolates showing multidrug resistance (MDR) were examined for the presence of exoS, toxA, mexA, and mexB. The sensitivity of those isolates and their virulence genes expression profiles were evaluated following treatment with Origanum marjoram and Origanum vulgare. Analyzed water samples showed a high load of total and fecal coliforms and indicated faecal contamination. The prevalence of P. aeruginosa in examined fish was 6.11%. All isolates harboured the oprL gene and showed different sensitivity to the antimicrobial agents. Only four isolates showed MDR and harboured all genes of interest. Both herbal extracts were effective and reduced the expression levels of exoS and toxA genes, even at subinhibitory concentrations. Despite the pathogenicity and antibiotic-resistance patterns of P. aeruginosa, it can be controlled by herbal medication, and thus encourages their use as antibiotic surrogates in aquaculture.

Isolation and identification of Enterococcus faecalis from cultured Oreochromis niloticus and Mugil cephalus with a special emphasis on a possible integrated control strategy

“…These active compounds can directly damage the cell membrane of Gram-positive bacteria, causing cell wall leakage, blocking enzyme systems and disruption of ion exchange (Burt, 2004;Holley & Patel, 2005). Moreover, carvacrol offers good antibacterial activity against various pathogenic bacteria by reducing virulence-related gene expression, impermeability and depolarization of the cytoplasmic membrane (Mabrok & Wahdan, 2018;Magi et al, 2015;Wahdan et al, 2020). In this study, there was a negative correlation coefficient between OEO concentrations and bacterial growth, which is in agreement with Popova and Bankova (2016) who reported that oregano oil showed a higher inhibitory effect on E. faecalis when given at low concen- (Tezel & Pavlostathis, 2015).…”

Valorization of biodiesel side stream waste glycerol for rhamnolipids production by Pseudomonas aeruginosa RS6

“…P. aeruginosa rarely causes infections in healthy individuals, but it is a major threat to patients with malignancies or HIV infection, patients who are mechanically ventilated, patients, and individuals who are immunocompromised (Sadikot et al, 2015). P. aeruginosa generates an amazing array for both cell-associated and extracellular virulence factor to facilitate the establishment of infection (Wahdan et al, 2020). Numerous molecular methods to determine species level of Pseudomonas sp.…”