Table 2. Phage therapy in the livestock industry over the last two decades

Animals	Target bacteria	Symptoms	Phage application	Therapeutic activity	References
Bovine	S. aureus (MDR)	Mastitis	SAH-1	Significantly reduced bacterial growth at MOIs of 1–100	[111]
	S. aureus (MRSA)		Six phage cocktails	Reduced S. aureus CFU counts by 64%–95%	[112]
	S. aureus (MSSA, MRSA VISA)		Five phage cocktails	Reduced colonization in the mouse mammary gland 8 h after treatment and prophylactically 4 h before challenge was most effective	[113]
	S. aureus (MRSA)		PhiSA012, PhiSA039	Intravenous and intraperitoneal administration of SA012 reduced bacterial colonization and inflammation of the mammary gland.	[114-116]
	S. aureus (MRSA)		vB_SauM_SDQ	Lysed 20 of the 24 strains reduced established biofilms on polystyrene, milk, and mammary gland tissue after treatment.	[117]
	S. aureus (MRSA)		Phage 24 A2	Lysed 19 of the 30 strains examined. Phage-cleared bacterial cultures on agar at a MOI of 10, supporting topical application for therapeutic use	[118]
	S. aureus (MRSA)		SLPW	Lysed 36 of the 40 isolates examined. Phage administration remedially reduced colonization and inflammation of cytokines in mice.	[119]
	E. coli (MDR)	Diarrhea	Three-phage cocktails	A cocktail of the phages reduced colonization, somatic cells, and inflammatory factors and alleviated symptoms of mastitis in cattle.	[42]
	E. coli (MPEC)		vB_EcoM_UFV13	A 10-fold reduction in bacterial load was observed at a MOI of 10 in mice.	[120]
	E. coli (ETEC, EPEC)		Three-phage cocktails	The probiotic-phage suppositories reduced the duration of diarrhea in calves, completely eliminating it within 24–48 h after use.	[42]
	E. coli (ETEC)		VTCCBPA9	VTCCBPA9 showed bactericidal activity against 47.3% (62/131) E. coli isolates, including three ETEC strains.	[121]
Swine	S. Enteritidis	Salmonellosis	Phage cocktail	3.5 log CFU reduction of S. Enteritidis PT4 per gram of cecal content	[122]
	S. Enteritidis		Felix 01	100% efficacy in eliminating S. Enteritidis strains from tonsils 6 h after application of bacteriophage suspension	[123]
	S. Typhimurium		Phage with probiotics	Significant influence on the growth of weaned pigs in comparison with pigs not treated with phages	[124]
	S. Typhimurium		Single phage	Significant reduction (99%) or complete elimination (100%) of S. Typhimurium strains in ileum, tonsils, and cecum samples within 48 h after the first administration	[48]
	S. Typhimurium		Phage cocktail	Significant reduction in the concentration of 2 of 3 serovars (S. Enteritidis and Typhimurium) by 2–4 log CFU after administration of bacteriophage suspension at 1011 PFU	[125]
	S. Typhimurium		Phage cocktail	100% reduction of the Salmonella ATCC 14028 reference strain and 92.5% of field isolates	[126]
	E. coli (ETEC)	Diarrhea	Phage cocktail	In comparison with the control group, the E. coli K88 CFUs in the duodenum, jejunum, ileum, cecum, colon, and mesenteric lymph nodes were lower in each phage-treated group, with differences at log levels of 0.83, 1.61, 1.67, 2.4, 1.47, and 1.65, respectively.	[58]
	E. coli		A221	With the treatment of phage A221, the body weight of piglets increased, and the percentage of Enterobacteriaceae in duodenum decreased to 0.64%.	[127]
	E. coli (MDR)		PT-10	When comparing the E. coli CFU in the feces between the phage-treated group and the control group, a difference of 4 log levels was observed on the 10th day.	[103]
	E. coli (ETEC)		Single phage	When comparing the number of E. coli isolated from challenged pig feces to the control group, there was an average difference of 1 log level throughout the experimental period.	[128]
Chicken	C. jejuni	Campylobacteriosis	Cj6	The maximum (2 log10 levels) reduction was achieved in samples that were treated with high densities of C. jejuni and high MOI of the phage at both storage temperatures.	[66]
	C. jejuni		Three-phage cocktails	2 log10 levels of reduction were achieved using the cocktail consisting of the three phages.	[129]
	C. jejuni		CP81	No reduction was observed at 4°C in situ on meat or in vitro. 1 log10 reduction was observed in vitro at 37°C.	[67]
	C. jejuni		Phage cocktail	3.2 log10 CFU/g lower C. jejuni counts than in the control until slaughter	[71]
	C. jejuni		Φ3, Φ15	Modest reduction of 0.2 log10 level. 0.8 log10 at 4°C	[130]
	S. Gallinarum	Salmonellosis	CJø01	Treatment using bacteriophages as a feed additive for chickens having contact with infected individuals led to a mortality rate of only 5%, as compared with 30% in the group that did not receive phage therapy.	[75]
	S. Enteritidis		PSE	100% efficacy in eliminating S. Enteritidis strains from the tonsils, 6 h after application of bacteriophage suspension	[131]
	S. Enteritidis		CJ07	The highest doses of bacteriophage significantly inhibited the replication of pathogens in the digestive tract of the chickens.	[132]
	S. Typhimurium		Three-phage cocktails	10-fold reduction in bacteria in the chicken ileum, cecum, liver, and spleen	[76]

In the livestock industry, various studies have been conducted to address the prevalent issue of pathogenic bacteria and bacterial diseases. This summary compiles research efforts aimed at preventing bacterial diseases in livestock through the application of bacteriophages. Numerous studies have been conducted, and further advancements in research are anticipated. The “Phage application” section provides information on the names or numbers of phages used in the treatment.
S. aureus, Staphylococcus aureus; MDR, multi-drug resistance; MSSA, methicillin-sensitive Staphylococcus aureus; MRSA, methicillin-resistant Staphylococcus aureus; VISA, vancomycin Intermediate Staphylococcus aureus (VISA); E. coli, Escherichia coli; MPEC, mammary pathogenic E. coli; ETEC, enterotoxigenic Escherichia coli; EPEC, enteropathogenic E. coli; C. jejuni, Campylobacter jejuni.