Table 1.

In vitro and in vivo studies on phage efficacy in the treatment of urinary tract infections (UTIs).

Target Bacteria	Phage Type	Description	Outcome	Type of Study	Reference
S. aureus E. coli Streptococcus spp. P. aeruginosa P. mirabilis	Pyophage cocktail (Eliava BioPreparations Ltd., Tbilisi, Georgia) *	Bacterial strains isolated from 118 clinical urine samples from patients planned for resection of prostate were tested against Pyo preparation before and after adaptation (selecting h-mutants with a broader and stronger host–phage interaction).	Before adaptation: 24% strains were sensitive, 16% moderately sensitive, 60% resistant After adaptation: 41% strains were sensitive, 34% moderately sensitive, 25% resistant	in vitro	[47]
S. aureus E. coli Streptococcus spp. P. aeruginosa P. mirabilis	Pyophage cocktail (Eliava BioPreparations Ltd., Tbilisi, Georgia) *	Nine patients aged 56–85 subjected to resection of prostate received Pyo preparation intravesically two times daily for 7 days, starting the first day after surgery. The solution of 20 mL was retained in the bladder for approximately 30–60 min.	Bacterial count decreased from two to seven orders (below limit of detection) in 6 patients, remained at the same level in 1 patient and in 1 patient Enterococcus strain was replaced by E. coli post-treatment growth with increased bacterial count.	in vivo	[47]
Enterobacter cloacae	Three phages (E-2, E-3 and E-4) isolated from wastewater treatment plant	E. cloacae was challenged with the three phages, separately and in a cocktail both in PBS buffer and urine sample at MOI 100.	Three tested phages were effective to inactivate E. cloacae in a buffer solution when used individually or, with significantly higher inactivation, in phage cocktails. Inactivation in urine was significantly lower but occurred with phage stability in urine lasting up to 12 h.	in vitro	[60]
UPEC	Three phages (vB_EcoP_ACG-C91, vB_EcoM_ACG-C40 and vB_EcoS_ACG-M12) isolated from sewage which were able to lyse 80.5% of a subset (42) of the UPEC strains able to form biofilms.	UTI E. coli isolate Can 91 was selected to determine the phage effectiveness to degrade biofilms because of the isolate’s ability to form strong biofilms in microtiter wells after 48 h and its sensitivity to all the three phages isolated.	All phages significantly reduced the biofilm within 2–12 h of incubation. Correlation was observed between phage sensitivity and specific serotypes of the UPEC strains.	in vitro	[61]
Multidrug-resistant Klebsiella pneumoniae isolated from urine	Cocktail of five Klebsiella phages (Kp165, Kp166, Kp167, Kp158, Kp169) with lytic coverage to isolated Klebsiella strain	A 63-year-old female patient with recurrent UTI with a long history of type 2 diabetes mellitus and hypertension was unsuccessfully treated with phages (phage resistant mutants developed within days)	Phage therapy combined with non-active antibiotics completely eliminated pathogenic strain and the recurrent UTI symptoms subsequently disappeared. No signs of recurrence were observed for this patient under antibiotic-free conditions during 6 months of follow-up.	in vivo	[62]
Proteus mirabilis isolated from UTIs	Three lytic Proteus phages (ΦRS1-PmA, ΦRS1-PmB, and ΦRS3-PmA) isolated from wastewater treatment plant	P. mirabilis cell suspensions were inoculated directly into the in vitro bladder models at either 1010 CFU or 103 CFU, representing late-stage or early stage-infection, respectively.	In model with an established infection, a single dose of the phage cocktail (1010 PFU; MOI 1) significantly extended the time needed to develop biofilm. In model with early infection: the phage cocktail completely prevented catheter blockage and eradicated infection.	in vitro	[63]
12 P. aeruginosa and 10 P. mirabilis isolates (almost exclusively clinical and urinary tract related strains)	The anti-Pseudomonas cocktail contained six P. aeruginosa phages (ΦPaer4, ΦPaer14, M4, 109, ΦE2005-A, and ΦE2005-C,) The anti-Proteus phage cocktail contained four P. mirabilis phages (ΦPmir1, ΦPmir32, ΦPmir34, and ΦPmir37)	The biofilm formation was determined in a flowing catheter reactor model over a three to four-day period with the use of artificial urine medium (AUM). Phage cocktail against Pseudomonas (1 × 109 PFU/mL each) and against Proteus (3 × 108 PFU/mL each) were used. Hydrogel-coated catheters were pretreated with one or both cocktails. The bacterial strains used for challenge were grown overnight in AUM and sub-cultured at initial concentration of approx. 1 × 103 CFU/Ml.	Phage pretreatment reduced P. aeruginosa biofilm counts by 4 log10 CFU/cm2 (p ≤ 0.01) and P. mirabilis biofilm counts by >2 log10 CFU/cm2 (p ≤ 0.01) over 48 h.	in vitro	[64]
ESBL-positive K. pneumoniae	Klebsiella phage obtained from Eliava Institute in Tbilisi, Georgia	58-year-old renal transplant patient with UTI. Phage regimen included oral application and bladder irrigation for four weeks, followed by oral and intravesical application every second day over an eight-week period.	Recurrent UTI by an ESBL-positive K. pneumoniae strain was successfully treated with a combination of meropenem and phages after failure of antibiotic therapy applied alone.	in vivo	[65]
Enterococcus spp., E. coli, P. mirabilis, P. aeruginosa, Staphylococcus spp., and Streptococcus spp.	Pyophage cocktail (Eliava BioPreparations Ltd., Tbilisi, Georgia) *	Male patients >18 years of age qualified for prostate resection with complicated or recurrent uncomplicated UTI received intravesically 20 mL of Pyophage or placebo twice daily for 7 days	Phage treatment turned out to be non-inferior to typical antibiotic treatment but was not superior to bladder irrigation (placebo).	in vivo	[66]

* active against a broad spectrum of uropathogenic bacteria: Staphylococcus aureus, E. coli, Streptococcus spp., Enterococcus spp., CFU—colony forming unit; ESBL—extended-spectrum β-lactamase; MOI—multiplicity of infection; PFU—plaque-forming unit; UPEC—uropathogenic E. coli.