Volume 61 (2022): Issue 3 (September 2022)

Antimicrobial resistance is becoming a paramount health concern nowadays. The increasing drug resistance in microbes is due to improper medications or over usage of drugs. Bacteria develop many mechanisms to extrude the antibiotics entering the cell. The most prominent are the efflux pumps (EPs). EPs play a significant role in intrinsic and acquired bacterial resistance, mainly in Gram-negative bacteria. EPs may be unique to one substrate or transport several structurally different compounds (including multi-class antibiotics). These pumps are generally associated with multiple drug resistance (MDR). EPs are energized by a proton motive force and can pump a vast range of detergents, drugs, antibiotics and also β-lactams, which are impermeable to the cytoplasmic membrane. There are five leading efflux transporter families in the prokaryotic kingdom: MF (Major Facilitator), MATE (Multidrug And Toxic Efflux), RND (Resistance-Nodulation-Division), SMR (Small Multidrug Resistance) and ABC (ATP Binding Cassette). Apart from the ABC family, which utilizes ATP hydrolysis to drive the export of substrates, all other systems use the proton motive force as an energy source. Some molecules known as Efflux Pump Inhibitors (EPI) can inhibit EPs in Gram-positive and Gram-negative bacteria. EPIs can interfere with the efflux of antimicrobial agents, leading to an increase in the concentration of antibiotics inside the bacterium, thus killing it. Therefore, identifying new EPIs appears to be a promising strategy for countering antimicrobial drug resistance (AMR). This mini-review focuses on the major efflux transporters of the bacteria and the progress in identifying Efflux Pump Inhibitors.

A new class of feed additives and nutritional supplements, known as probiotics, include bacterial, fungal, and yeast cultures from various sources. Overall, probiotics are believed to promote the health and well-being of animals, birds, and humans in a variety of settings. Incorporating probiotics into the diets of cattle and poultry has been demonstrated to improve growth, feed conversion efficiency, immunological responses, and the animal's ability to manage enteric infections. The use of probiotic-enriched chicken feed has been shown to enhance egg production by as much as 30% among laying chickens. Probiotics may be used to fight off harmful microorganisms, create antibacterial compounds (such as bacteriocins or colicins), and alter the immunological response of the host, according to the National Institutes of Health. Pathogenic microbial strains such as Lactobacillus, Streptococcus, Bacillus, Enterococcus, Pediococcus, Aspergillus, and Saccharomyces are employed in the making of chicken products. The use of subtherapeutic doses of antimicrobial agents, including antibiotics, to combat or remove harmful bacteria and promote animal growth and feed efficiency has resulted in the accumulation of antibiotic residues in animal feed as well as the emergence of drug-resistant microbes in the feed supply chain. As a result of public health concerns, there has been a renewed emphasis on the use of probiotics in chicken production rather than antibiotics in recent years. This research examines the effects of probiotics and direct-fed microorganisms (DFM) on chicken health and performance, with a particular emphasis on the favourable effects they have on poultry health and performance.