New β-Lactam Antibiotics and Ceragenins – A Study to Assess Their Potential in Treatment of Infections Caused by Multidrug-Resistant Strains of Pseudomonas aeruginosa

Figures & data

Table 1 Source of Clinical Pseudomonas aeruginosa Strains (n=150)

Source	Number of Strains
Blood	37
Urine	17
Skin and soft tissues, including surgical wounds	41
Lower respiratory tract	34
Upper respiratory tract	8
Others (screening tests)	13

Table 2 Characteristics of Group of Pseudomonas aeruginosa Strains (n=150)

Group I (n=22)	Strains susceptible to all tested β-lactams
Group II (n=40)	Strains (resistant/not susceptible) to karbapenems and susceptible to other β-lactams
Group III (n=67)	Strains resistant to all tested β-lactams, MBL-negative; XDR strains
Group IV (n=13)	Strains resistant to all tested β-lactams, MBL-positive; XDR strains
Group V (n=8)	Strains susceptible to karbapenems with variable pattern of resistance to other β-lactams; MDR strains

Table 3 MIC Range, MIC₅₀, MIC₉₀, and Susceptible Rate of C/T, C/A, M/V, and Colistin Against Pseudomonas aeruginosa Strains (n=150)

Group of Strains/ Control Strain	Antibiotic	MIC Range (µg/mL)	MIC50 (µg/mL)	MIC90 (µg/mL)	MBC Range (µg/mL)	S
All clinical P. aeruginosa (n=150)	Ceftolozane/tazobactam	0.25–>256	2	64	ND	87%
	Ceftazidime/awibactam	1–>256	4	32	ND	88%
	Meropenem/vaborbactam	0.125–256	8	64	ND	51%
	Colistin	0.125–8	1	2	ND	98%
Group I (n=22)	Ceftolozane/tazobactam	0.5–2	1	1	ND	100%
	Ceftazidime/awibactam	1–4	2	2	ND	100%
	Meropenem/vaborbactam	0.125–4	0.25	2	ND	100%
	Colistin	0.5–8	1	2	ND	91%
Group II (n=40)	Ceftolozane/tazobactam	0.25–>256	1	2	ND	95%
	Ceftazidime/awibactam	1–256	2	8	ND	95%
	Meropenem/vaborbactam	0.25–64	8	16	ND	78%
	Colistin	0.125–4	1	2	ND	98%
Group III (n=67)	Ceftolozane/tazobactam	0.5–>256	2	4	ND	93%
	Ceftazidime/awibactam	1–>256	4	8	ND	96%
	Meropenem/vaborbactam	0.125–64	16	32	ND	22%
	Colistin	0.25–2	1	2	ND	100%
Group IV (n=13)	Ceftolozane/tazobactam	256–>256	256	>256	ND	0%
	Ceftazidime/awibactam	16–>256	64	256	ND	0%
	Meropenem/vaborbactam	32–256	256	256	ND	0%
	Colistin	0.5–2	1	2	ND	100%
Group V (n=8)	Ceftolozane/tazobactam	1–8	2	2	ND	100%
	Ceftazidime/awibactam	2–8	2	8	ND	100%
	Meropenem/vaborbactam	0.125–1	0.25	1	ND	100%
	Colistin	0.5–2	1	2	ND	100%
P. aeruginosa ATCC 27853	Ceftolozane/tazobactam	0.75	–	–	ND	–
	Ceftazidime/awibactam	0.75	–	–	ND	–
	Meropenem/vaborbactam	0.25	–	–	ND	–
	Colistin	0.25	–	–	ND	–

Abbreviations: ND, not determined; S, susceptible strains.

Table 4 Summarized MIC Range, MIC₅₀, MIC₉₀, and Susceptible Rate of C/T, C/A, and M/V Against CRPA Strains (n=120)

Group of Strains	Antibiotic	MIC range (µg/mL)	MIC50 (µg/mL)	MIC90 (µg/mL)	MBC range (µg/mL)	S
Group II, III, IV (n=120)	Ceftolozane/tazobactam	0.25–>256	2	256	ND	83%
	Ceftazidime/awibactam	1–>256	4	32	ND	85%
	Meropenem/vaborbactam	0.125–256	16	64	ND	38%
	Colistin	0.125–4	1	2	ND	99%

Abbreviations: ND, not determined, S, susceptible strains.

Table 5 MIC Range, MIC₅₀, MIC_90, MBC Range, MBC₅₀, and MBC₉₀ of Ceragenins Against Pseudomonas aeruginosa Strains (n=150)

Group of Clinical Strains/Control Strain	Ceragenin	MIC range (µg/mL)	MIC50 (µg/mL)	MIC90 (µg/mL)	MBC range (µg/mL)	MBC50 (µg/mL)	MBC90 (µg/mL)
All clinical P. aeruginosa (n=150)	CSA13	0.5–8	2	4	0.5–8	4	8
	CSA44	0.5–8	2	4	0.5–8	4	8
	CSA131	0.5–4	1	2	0.5–8	2	4
Group I (n=22)	CSA13	1–4	2	4	1–8	4	8
	CSA44	1–8	2	4	1–8	4	8
	CSA131	0.5–4	2	4	1–8	2	4
Group II (n=40)	CSA13	0.5–8	2	4	0.5–8	4	8
	CSA44	1–4	2	4	1–8	2	8
	CSA131	0.5–4	1	2	0.5–8	2	4
Group III (n=67)	CSA13	0.5–4	2	4	0.5–8	4	8
	CSA44	0.5–4	2	2	0.5–8	4	8
	CSA131	0.5–4	1	4	0.5–8	2	4
Group IV (n=13)	CSA13	1–4	2	4	1–8	4	4
	CSA44	2–4	2	2	2–4	2	4
	CSA131	1–2	1	2	1–4	2	2
Group V (n=8)	CSA13	2–8	4	8	2–8	4	8
	CSA44	2–4	2	4	2–8	4	8
	CSA131	0.5–2	1	2	1–2	1	2
Pseudomonas aeruginosa ATCC 27853	CSA13	2	–	–	2	–	–
	CSA44	2	–	–	2	–	–
	CSA131	1	–	–	1	–	–

Figure 1 Range of the minimum inhibitory concentrations (MICs) of ceftolozane-tazobactam, meropenem-vaborbactam and ceftazidime-avibactam recorded for P. aeruginosa strains (A - group I, C- group II, E - group III, G - group IV, I - group V) and CSAs (CSA-13, CSA-44, CSA-131) (B - group I, D - group II, F - group III, H - group IV, J - group V). Compared for the reference strain of P. aeruginosa ATCC 27853 MIC value for ceftolozane-tazobactam was 0.75 μg/mL, ceftazidime-avibactam – 0.75 μg/mL, meropenem-vaborbactam – 0.25 μg/mL, CSA-13 – 2 μg/mL, CSA-44 - 2 μg/mL and CSA-131 - 1 μg/mL.

Figure 2 Range of the minimum inhibitory concentrations (MIC) of CSA ((A) CSA-13, (B) group CSA-44, (C) group CSA-131) in combination with pluronic F127 0.5, 1, 2, and 5% in doses of 1–50 μg/mL.

Table 6 Summarized MIC Range, MIC₅₀, MIC₉₀ MBC Range, MBC₅₀, and MBC₉₀ of CSA13, CSA44, and CSA131 Against CRPA Strains (n=120)

Group of Clinical Strains/Control Strain	Antimicrobial Agent	MICs (µg/mL) Range	MIC50 (µg/mL)	MIC90 (µg/mL)	MBCs (µg/mL) Range	MBC50 (µg/mL)	MBC90 (µg/mL)
Group II, III, IV (n=120)	CSA13	0.5–8	2	4	0.5–8	4	8
	CSA44	0.5–4	2	4	0.5–8	2	8
	CSA131	0.5–4	1	2	0.5–8	2	4

Figure 3 MICs values for P. aeruginosa ATCC 27853 (A), and representative strains from group I (B), group II (C), group III (D), group IV (E), and group V (F) of CSA-13, CSA-44, and CSA-131 during serial passages.

Figure 4 Relative biofilm mass of P. aeruginosa during treatment with CSA-13, CSA-44, and CSA-131. Formation of biofilm in the presence of CSAs ranging from 1–50 μg/mL was assessed using the resazurin-based fluorimetric method after 24 (A), 48 (B), and 72 (C) hours incubation. Results show mean±SD from three measurements. * indicates statistical significance.

Figure 5 Hemoglobin release from human red blood cells (RBCs) incubated in the presence of CSA-13 (A–C), CSA-44 (D–F), and CSA-131 (G–I) alone and with 1%, 2%, and 5% pluronic at doses of 1–50 μg/mL after 1 hour (A, D, G), 6 hours (B, E, H), and 12 hours (C, F, I). Results show mean±SD, n=3; * indicates statistical significance.

Figure 6 Viability of lung adenocarcinoma cells (A549) upon treatment with CSA alone and with 1%, 2%, and 5% pluronic at doses of 1–50 μg/mL. CSA-13 (A), CSA-44 (B), and CSA-131 (C). Results show: mean±SD, n=3; * indicates statistical significance.