Synergistic and Antagonistic Effects of Metal Nanoparticles in Combination with Antibiotics Against Some Reference Strains of Pathogenic Microorganisms

Figures & data

Table 1 The Antibiotics Used with Their Antimicrobial Subclasses Along with the Discs Concentration Against E. coli, Staph. aureus, Salmonella spp and C. albicans

Antimicrobial Classes	Antimicrobial Agent	Disc Concentration
Macrolides	Azithromycin (AZM)	15 μg
Aminoglycosides	Gentamicin (CN)	10 μg
Penicillins	Oxacillin (OX)	1 μg
3rd generation of cephalosporin	Cefotaxime (CTC)	40 μg
Aminoglycosides	Neomycin (N)	30 μg
β-lactam/β-lactamase inhibitor combinations	Ampicillin/Sulbactam (SAM)	20 μg
2nd generation of cephalosporin	Cefuroxime (CXM)	30 μg
Broad spectrum antibiotics	Fosfomycin (FF)	50 μg
Phenicols	Chloramphenicol (C)	30 μg
Tetracyclines	Oxytetracycline (T)	30 μg

Figure 1 UV-Vis absorption spectra of metal nanoparticles (A) Ag-NPs (B) ZnO-NPs.

Figure 2 Transmission electron microscopy of metal nanoparticles (A) Ag-NPs (B) ZnO-NPs.

Figure 3 Scanning electron microscopy of metal nanoparticles (A) Ag-NPs (B) ZnO-NPs.

Table 2 Antimicrobial Activity of AgNPs Against E. coli, Staphylococcus aureus, Salmonella spp and C. albicans

Concentration of AgNPs (µg/mL)	Zone of Inhibition (mm)
	E. coli	Staph. aureus	Salmonella spp	C. albicans
170	26 ±0.57^a	27±0.57^a	20±0.59^b	No
85	20±1.15^b	22±1.73^a	18± 0.57^c	No
42.5	18 ±0.57^a	19±0.57^a	16±1.73^b	No
21.25	16±0.57*	15±1.15*	14±0.57*	No
10.625	15±0.57^a	14±1.73^a	12±0.57^b	No
5.31	14±1.73^a	13±0.57^a	11±1.15^b	No
2.65	13	11	No	No
1.33	11	No	No	No
0.66	No	No	No	No

Notes: *Non significant; ^a,b,cStatistical significant difference (P<0.05), a>b>c.

Table 3 Synergistic and Antagonistic Effect of AgNPs in Combination with Various Antibiotics Against E. coli, Staph. aureus, Salmonella spp

E. coli
	Azithromycin	Gentamicin	Oxacillin	Cefotaxime	Neomycin	Ampicillin/Sulbactam	Cefuroxime	Fosfomycin	Chloramphenicol	Oxytetracycline
Antibiotic only	28.00±0.57^b	31.00±0.55^a	19.00±0.57	0.00±0.00^b	27.00±0.54	30.00±0.45	0.00±0.00^b	0.00±0.00^b	27.00±0.77^b	22.00±0.56
AgNPs with antibiotic	41.00±0.577^a	28.00±0.58^b	20.00±0.56	34.00±0.57^a	25.00±0.57	32.00±0.84	37.00±0.67^a	32.00±0.57^a	36.00±0.75^a	22.00±0.53
P value	***	*	NS	***	NS	NS	***	***	***	NS
Staph. aureus
Antibiotic only	27.00±0.49^b	27.00±0.45	33.00±0.57^a	0.00±0.00^b	30.00±0.56^a	25.00±0.76^b	0.00±0.00^b	0.00±0.00^b	29.00±0.47^b	32.00±0.57^b
AgNPs with antibiotic	40.00±0.53^a	28.00±0.56	23.00±0.59^b	24.00±0.57^a	25.00±0.57^b	38.00±0.75^a	22.00±0.57^a	18.00±0.57^a	34.00±0.45^a	40.00±0.57^a
P value	***	NS	***	***	***	***	***	***	***	***
Salmonella spp
Antibiotic only	20.00±0.34^b	17.00±0.57^b	0.00±0.00 ^b	21.00±0.57^b	14.00±0.73^b	22.00±0.75^b	0.00±0.00 ^b	0.00±0.00^b	27.00±0.57 ^b	20.00±0.54^b
AgNPs with antibiotic	32.00±0.32^a	28.00±0.57^a	36.00±0.67^a	28.00±0.57^a	28.00±0.75^a	24.00±0.77^a	25.00±0.45^a	34.00±0.65^a	40.00±0.57^a	35.00±0.48^a
P value	***	***	***	***	***	*	***	***	***	***

Notes: *<0.05; ***<0.001; ^a,bStatistical significant difference (P<0.05), a>b.

Abbreviation: NS, Non-Significant.

Table 4 Antimicrobial Activity of ZnONPs Against E. coli, Staph. aureus, Salmonella spp and C. albicans

Concentration of ZnONPs (mg)	Zone of Inhibition (mm)
	E. coli	Staph. aureus	Salmonella spp	C. albicans
10	26±1.33^a	20±0.57^b	15±0.57^c	No
5	22±1.23^a	17±0.75^b	13±0.57^c	No
2.5	18±0.57^a	15±0.75^a	12±0.75^b	No
1.25	14±0.75^a	13±0.57^a	10±0.57^b	No
0.6	No	No	No	No

Notes: ^a,b,cStatistical significant difference (P<0.05), a>b>c.

Table 5 Synergistic and Antagonistic Effect of ZnONPs in Combination with Various Antibiotics Against E. coli, Staph. aureus, Salmonella spp

E. coli
	Azithromycin	Gentamicin	Oxacillin	Cefotaxime	Neomycin	Ampicillin/Sulbactam	Cefuroxime	Fosfomycin	Chloramphenicol		Oxytetracycline
Antibiotic only	27.00±0.67^b	30.00±0.66	19.00±0.57^b	0.00±0.00^b	27.00±0.56	30.00±0.75^a	0.00±0.00^b	0.00±0.00^b	27.00±0.75		23.00±0.53^b
ZnONPs with antibiotic	35.00±0.56^a	32.00±0.57	33.00±0.57^a	35.00±0.45^a	27.00±0.66	23.00±0.73^b	27.00±0.54^a	33.00±0.56^a	27.00±0.87		30.00±0.34^a
P value	***	NS	***	***	NS	***	***	***	NS		***
Staph. aureus
Antibiotic only	27.00±0.56^b	27.00±0.86	33.00±0.45^a	0.00±0.00^b	30.00±0.72^a	25.00±0.53^a	0.00±0.00^b	0.00±0.00^b	29.00±0.75^b	32.00±0.68^b
ZnONPs with antibiotic	30.00±0.52^a	27.00±0.67	18.00±0.43^b	15.00±0.43^a	13.00±0.64^b	19.00±0.61^b	12.00±0.42^a	15.00±0.53^a	32.00±0.75^a	40.00±0.76^a
P value	*	NS	***	***	***	***	***	***	*	***
Salmonella spp
Antibiotic only	20.00±0.53^a	17.00±0.87^a	0.00±0.00^b	21.00±0.75^a	14.00±0.53^a	22.00±0.32^a	0.00±0.00^b	0.00±0.00^b	27.00±0.51^a	20.00±0.43^a
ZnONPs with antibiotic	14.00±0.58^b	12.00±0.86^b	10.00±0.56^a	16.00±0.87^b	0.00±0.00 ^b	12.00±0.75^b	17.00±0.87^a	18.00±0.54^a	14.00±0.59^b	13.00±0.56^b
P value	***	***	***	***	***	***	***	***	***	***

Notes: *<0.05; ***<0.001; ^a,bStatistical significant difference (P<0.05), a>b.

Abbreviation: NS, Non-Significant.