Table 1.
Phage-derived polysaccharide depolymerases efficacy in vivo.
| Enzyme | Pathogen | Animal | Infection | Inoculum | Dosing | Results | Ref. |
|---|---|---|---|---|---|---|---|
| P22 tailspike protein (P22sTsp) recognizing LPS |
Salmonella enterica serovar Typhimurium | Leghorn chicks | Intestinal colonization | Oral gavaging, 300 µL PBS containing 104 to 107 CFU |
Oral gavaging, 300 µL in 10% BSA containing 30 mg; 3 doses: 1st 1 h post-infection, 2nd and 3rd dose given in 24 h intervals | 100-fold reduction of Salmonella colonization in the gut as well as reduced liver and spleen penetration; Salmonella motility was impaired | [150] |
| Dep-ORF8 targeting capsular serogroup A |
Pasteurella multocida capsular serogroup A | BALB/c mouse model | Systemic infection | IP injection of 100 µL containing 80 CFU | 3 treatment groups: IP injection of 100 µL containing 36 µg at 6 h (group 1), 12 h post-infection (group 2), and 12 h post-infection, and then once daily for 5 days (group 3) |
Treatment: group 1 showed ~70%, and 50% survival within 3 and 5 days, respectively; group 2 showed 70%, 50%, and ~35% survival within 3, 5, and 12 days, respectively; group 3 showed ~80%, 70% survival within 4 and 6 days, respectively; control group 100% mortality within 5 days |
[151] |
| gp49, O-specific polysaccharide lyase |
Pseudomonas aeruginosa |
Galleria mellonella (Wax moth larvae) |
Hemocoel infection |
Injection into the last pro-leg of 10 CFU | Pretreatment: 1h incubation of bacteria with 50 µg/mL; treatment: 5 or 50 µg/mL was injected 15 min post-infection |
Pretreatment: 24 h post injection, 50% of larvae survived (~30% more than in the control); 35% larvae also survived to the end of the experiment (>72 h); treatment: 24 h post-treatment, the larvae survival rate was at least 20% higher compared to the control, independent of gp49 concentration; 20% of larvae survived up to 72 h with treatment, while 100% of control group died 48 h post injection |
[105] |
| depoKP36 targeting KP36 capsule | Klebsiella pneumoniae |
G. mellonella (Wax moth larvae) |
Hemocoel infection |
Injection into the last pro-leg of 10 µL containing 107 CFU | Pretreatment: bacteria were pretreated with depoKP36 (280 µg/mL) for 2 h before infection; treatment: depoKP36 was administered 5 min post-infection |
Pretreatment: 77% of larvae were saved within 24 h, and 47% and 43% after 48h and 72 h, respectively; treatment: survival increased up to 40%, 30%, and 20% after 24 h, 48 h, and 72 h post-treatment, respectively; 100% of untreated larvae died |
[132] |
| Dp42 targeting capsular polysaccharide type KN1 |
K. pneumoniae | BALB/c mouse model | Systemic infection |
IP injection of 2 × 107 CFU |
Prevention: IP injection of 200 µL containing 0.25 mg/mL 6 h before bacterial infection; pretreatment: 0.25 mg/mL for 30 min; treatment: IP injection of 200 mL containing ~50 mg 30 min post-infection | Prevention: 100% survival within 96 h post-infection, while 100% of control group died within 9 h; pretreatment: 1 mouse died (12.5%) 54 h post-infection, while 100% of control group died within 12 h; treatment: identical to pretreatment results. |
[152] |
| K64dep targeting K64 capsular type polysaccharides |
K. pneumoniae | BALB/cByl mouse model CP treated, 200 mg/kg IP injections in 2 days intervals |
Systemic infection |
IP injection of 6 × 106 CFU |
IP injection with 150 μg, 37.5 μg, or 18.75 μg at 1 h, 8 h, and 24 h post-infection |
100% survival with 18.75 µg dose applied 1 h post-infection; in control group, 100% mortality was observed; 150 µg dose applied 8 h post-infection had no effect; no K64dep-related toxicity was observed as well as no changes in liver, kidney, and spleen histopathology; treatment sensitizes carbapenem-resistant K64 to serum killing in vitro as well as increased its susceptibility to neutrophil killing (~40% improved killing) |
[153] |
| Endosialidase E (endoE) |
Escherichia coli producing K1 antigen | Neonatal rats | Intestinal colonization and E. coli-related bacteremia |
Oral administration of 20 μL containing 2 to 6 × 106 CFU |
IP injection of 20 µg on days 1, 2, 3, 4, and 5 post-infection |
No direct effect on E. coli viability but pathogen is sensitized to complement system killing; single dose on day 1 of endoE prevents the death of infected pups and E. coli invasion of the bloodstream; 80–100% survival in comparison to 0–10% survival in untreated control |
[133] |
| Endosialidase E (endoE) |
E. coli producing K1 antigen | Neonatal rats | Intestinal colonization and E. coli-related bacteremia |
Oral administration of 20 μL containing 2 to 6 × 106 CFU |
IP injection of 0.125–20 µg range on days 1 post-infection |
Minimal dose of 0.25 µg prevented death of at least 80% of rats; treatment sensitizes E. coli to serum killing in vitro, and improved macrophage ingestion of E. coli |
[134] |
| Dep6, O91-specific polysaccharide depolymerase |
Shiga toxin-producing E. coli | BALB/c mouse thigh model | Systemic infection | Injection near the right thigh of 100 μL containing 2.4 × 108 CFU |
Dose: 100 μL containing 0.3 μg/μL; toxicity: IP injection; prophylactic: delivery 3 h prior to infection; simultaneous treatment: delivery at the same time as bacterial inoculum; delayed treatment: delivery 3 h post-infection |
Toxicity analysis: no pathological changes in liver, kidney, or small intestine observed; pretreatment: 100% survival; simultaneous treatment: 83% survival; delayed treatment: 33% survival; significant reduction in the levels of proinflammatory cytokines was observed at 24 h post-infection |
[138] |
| Capsule depolymerases active against three different capsule types: K1, K5, and K30 |
E. coli | NIH Swiss Mouse thigh model | Systemic infection |
Injection into thigh of 100 µL containing 1 to 4 × 108 CFU | Injection of 100 µL PBS containing 0, 2, 5, or 20 µg doses, 30 min post-infection; different depolymerases tested | Toxicity: no toxicity observed; treatment: control group did not survive, whereas most mice were rescued by treatment with 20 µg dose per mouse; effective doses of K1F and K1H enzymes were between 2 µg (both partially rescuing) and 5 µg (both rescuing 100% mice) per mouse; for K5, the effective dose was between 2 and 20 µg per mouse; K30 gp41 rescued mice at the higher dose tested (20 µg per mouse); a mixture of K30 gp41 and K30 gp42 yielded the same survival outcome as K30 gp41 alone |
[122] |
| ϕAB6 targeting capsular polysaccharide |
Acinetobacter baumannii | Zebrafish | Systemic infection |
Injection through cloaca of 1 to 4 × 107 CFU | Injection through cloaca of 20 μL protein (1 μg/μL), 30 min post-infection | Treatment: survival rate was significantly improved (80%) compared with untreated control (10%); toxicity: none observed |
[154] |
| Dpo48 capsule depolymerase |
A. baumannii | G. mellonella (Wax moth larvae) | Hemocoel infection |
Injected into the last pro-leg of 10 µL PBS containing 106 CFU | Pretreatment: 50 µg/mL for 1 h; treatment: Injection of 10 µL PBS containing 5 µg 5 min post-infection | Pretreatment: 100% survival, while, in control group, ~65% and 84% of larvae died within 24 h and 72 h, respectively; treatment: 76% survival, while, in control group, ~65% and 84% of larvae died within 24 h and 72 h, respectively |
[155] |
| Dpo48 capsule depolymerase |
A. baumannii | BALB/c mice model | Systemic infection |
IP injection of 107 CFU |
IP injection of 200 µL PBS containing 50 µg 2 h post-infection | 100% mice treated survived and appeared healthy for 7 days, while 100% of the untreated control died within 24 h due to peritoneal sepsis; bacterial count in tissue and organs was significantly reduced with treatment 6 h post-infection in comparison to control group | |
| BALB/c mice model, IP injection of CP (300 mg/kg) in 200 µL PBS, 3 days before infection |
Systemic infection |
IP injection of 107 CFU |
IP injection of 200 µL of PBS containing 50 µg 2 h post- infection | 100% of mice treated survived and appeared healthy for 7 days, while 100% of untreated control died within 24 h due to peritoneal sepsis | |||
| K2 capsular depolymerase |
A. baumannii capsular type K2 |
G. mellonella (Wax moth larvae) |
Hemocoel infection |
Injection into the last pro-leg of 5.5 µL of 20 mM HEPES containing 106 CFU | Pretreatment: bacteria pretreated with protein for 2 h; treatment: injection of enzyme 30 min post-infection; in both scenarios, a range of protein dosages were used (0.25 g, 0.5 g, and 3 g/larvae) | No toxicity, 100% survival of larvae; pretreatment: untreated control group survival rate was 25%, 20%, and 10% after 24, 48, and 72 h, respectively; in group with pretreatment after 72 h, 53%, 69%, and 88% of larvae survived using 0.25 g, 0.5 g, and 3 g pretreatments; treatment: only 35%, 22%, and <15% larvae survived in untreated control after 24 h, 48 h, 72 h, respectively, while 73%, 40–76%, 56–70% survived with treatment; K2 depolymerase is highly refractory to resistance development |
[156] |
| BALB/c mouse model, IP injection of CP (100 mg/kg), 4 and 1 day before infection |
Systemic infection |
IP injection of 107 CFU |
IP injection with 50 µg dose 1 h post-infection | 20 h post-infection control group had to be euthanized, while in a treatment group 90% mice had survived, decreasing to 60% at 42 h post-infection |
Abbreviations: (CP) cyclophosphamide, (IP) intraperitoneal.