Antimicrobial activity of cell free supernatants from probiotics inhibits against pathogenic bacteria isolated from fresh boar semen

Abstract

The use of antibiotics with semen extender appears to be a practical solution to minimise bacterial growth in fresh boar semen preservation. Unfortunately, the excessive use of antibiotics promotes antimicrobial resistance (AMR). This becomes a worldwide concern due to the antimicrobial resistance genes transmitted to animals, environment, and humans. Probiotics are one of the alternative methods to reduce antibiotic use. They could inhibit pathogenic bacteria by producing antimicrobial substances in cell free supernatants (CFS). Nevertheless, there is no comprehensive study undertaken on inhibitory activity against pathogenic bacteria isolated from boar semen origin. Our study investigated the efficacy of CFS produced from selected probiotics: Bacillus spp., Enterococcus spp., Weissella spp., Lactobacillus spp., and Pediococcus spp. inhibiting pathogenic bacteria isolated from fresh boar semen. Besides, the semen-origin pathogenic bacteria are subjected to identification, antimicrobial resistance genes detection, and antibiotic susceptibility test (AST). Pseudomonas aeruginosa, Escherichia coli, and Proteus mirabilis are the most common pathogens identified in boar semen with resistance to numerous antibiotics used in pig industry. The CFS with its antimicrobial peptides and/or bacteriocin constituent derived from selected probiotics could inhibit the growth of pathogenic bacteria carrying antimicrobial resistance genes (mcr-3 and int1 genes). The inhibition zones for Pseudomonas aeruginosa, Escherichia coli, and Proteus mirabilis provided more efficient results in the CFS derived from Lactobacillus spp. and Pediococcus spp. than those of the CFS produced from Enterococcus spp., Weissella spp. and Bacillus spp., respectively. It is worth noted that as the incubation time increased, the antibacterial activity decreased conversely. Our results on CFS with its antimicrobial peptides and/or bacteriocin constituent inhibits semen-origin pathogenic bacteria guide the direction as a promising alternative method used in the semen extender preservation of the pig industry.

The Effects of Different Antimicrobial Peptides (A-11 and AP19) on Isolated Bacteria from Fresh Boar Semen and Semen Quality during Storage at 18 °C

“…The bacteria in the present study were obtained from our previous report by Keeratikunakorn et al [7] in which three species of the most frequently found bacteria in fresh boar semen including E. coli, Pseudomonas aeruginosa, and Proteus mirabilis were isolated and kept in a culture collection at the Laboratory of Bacteria, Veterinary Diagnostic Center, Faculty of Veterinary Science, Mahidol University (Salaya, Phuttamonthon, Nakhon Pathom, Thailand). The bacteria E. coli, Pseudomonas aeruginosa, and Proteus mirabilis were all grown in a brain heart infusion (BHI, Difco, Reno, NV, USA) medium and incubated for 16-18 h at 37 • C. Pre-culture was performed by inoculating BHI broth with a single isolated colony and then shaking it at 200 rpm for 16-18 h at 37 • C. Before being used, a 1% concentration of the pre-culture was added to the BHI broth and kept to grow at 37 • C.…”

The Effect of Antimicrobial Peptide (PA-13) on Escherichia coli Carrying Antibiotic-Resistant Genes Isolated from Boar Semen

“…A rectal swab sample of diarrheal piglets revealed 100% resistance of E. coli to amoxicillin, and 97.3% of these bacteria exhibited multidrug resistance (MDR) [3]. Antibiotic-resistant genes have also been identified, including those from E. coli collected from diarrheal piglets and boar semen (int1, mcr-1 and mcr-3) [3,6]. It has been shown that among the bacteria isolated from sows with endometritis and those showing vaginal discharge (i.e., E. coli, Staphylococcus spp., and Streptococcus spp.…”

“…This particular AMP showed a compromised result in terms of inhibiting Gram-negative bacteria with MDR. According to studies at pig farms in tropical countries, bacteria in boar semen are resistant to multiple antibiotics, such as amoxicillin, gentamicin, and colistin, commonly used in pig farms and supplemented in the boar semen extender [6,15]. It has also been demonstrated that E. coli isolated from boar semen has a unique MDR pattern [6].…”

“…According to studies at pig farms in tropical countries, bacteria in boar semen are resistant to multiple antibiotics, such as amoxicillin, gentamicin, and colistin, commonly used in pig farms and supplemented in the boar semen extender [6,15]. It has also been demonstrated that E. coli isolated from boar semen has a unique MDR pattern [6]. However, no study has been reported on the efficacy of this PA-13 for inhibiting E. coli with MDR isolated from boar semen [6].…”

Investigate the impact of probiotics of lactic acid bacteria obtained from various local sources on some pathogenic bacteria

“…Individuals prone to recurrent infections often face persistent concerns, as antibiotic therapy is frequently ineffective due to drug resistance. Several probiotic strains, tested in a growing number of trials, have demonstrated promising effects in preventing or treating both acute and recurring infectious diseases (9)(10)(11).…”