Antimicrobial Resistance of Staphylococcus aureus Isolated from Hospital Wastewater in Kermanshah, Iran

Figures & data

Table 1 Primers Used for PCR Amplification of Antibiotic Resistance Genes.¹⁷

Gene Target	Sequence (5′→3′)	Amplicon Size (bp)	Annealing Temperature (ºC)
mecA-F	AAAATCGATGGTAAAGGTTGGC	532	56
mecA-R	AGTTCTGCAGTACCGGATTTGC
aacA-D -F	TAATCCAAGAGCAATAAGGGC	227	56
aacA-D -R	GCCACACTATCATAACCACTA
tetK-F	GTAGCGACAATAGGTAATAGT	360	54
tetK-R	GTAGTGACAATAAACCTCCTA
tetM-F	AGTGGAGCGATTACAGAA	158	54
tetM-R	CATATGTCCTGGCGTGTCTA
VatA-F	TGGTCCCGGAACAACATTTAT	268	56
VanA-R	TCCACCGACAATAGAATAGGG
VanB-F	GCTGCGAATTCAGTTGTTACA	136	55
VanB-R	CTGACCAATCCCACCATTTTA
VanC-F	AAGGCCCCAATCCAGAAGAA	467	56
VanC-R	TCAACGTTCTTTGTCACAACC

Table 2 Values of pH, Temperature, and Bacterial Load in Raw and Treated Sewage Samples

Parameter	Raw Sewage	Treated Sewage	p-value
Temperature, ºC (mean)	21.8	19.6	0.002
pH (mean)	7.71	7.39	0.003
Bacterial load, CFU/mL (mean)	7.5×10^6	6.1×10^6	0.45

Table 3 Antimicrobial Susceptibility of MSSA and MRSA Isolates in Raw and Treated Sewage Samples

Antibiotic	MSSA				P value	MRSA				P value
	Raw sewage (n=10)		Treated Sewage (n=10)			Raw Sewage (n=20)		Treated Sewage (n=20)
	S	N	S	N		S	N	S	N
Amoxicillin/Clavulanic acid	3(30)	7(70)	2(20)	8(80)	0.606	4(20)	16(80)	4(20)	16(80)	1
Azithromycin	2(20)	8(80)	1(10)	9(90)	0.531	0	20(100)	0	20(100)	–
Penicillin	0	10(100)	0	10(100)	–	0	20(100)	0	20(100)	–
Rifampin	10(100)	0	6(60)	4(40)	0.025	14(70)	6(30)	13(65)	7(35)	0.736
Tetracycline	2(20)	8(80)	2(20)	8(80)	1	8(40)	12(60)	14(70)	6(30)	0.057
Gentamicin	4(40)	6(60)	2(20)	8(80)	0.329	1(5)	19(95)	3(15)	17(85)	0.292
Oxacillin	6(60)	4(40)	6(60)	4(40)	1	0	20(100)	0	20(100)	–
Clindamycin	1(10)	9(90)	1(10)	9(90)	1	2(10)	18(90)	4(20)	16(80)	0.376

Note: Values have been expressed as number (%).

Abbreviations: N, non-susceptible; S, susceptible.

Figure 1 Comparison the antimicrobial susceptibility of S. aureus (MRSA and MSSA) isolates in raw (n=30) and treated (n=30) sewage samples.

Abbreviations: GEN, gentamicin; PEN, penicillin; AMC, amoxicillin/clavulanic acid; OXA, oxacillin; RIF, rifampicin; TET, tetracycline; AZM, azithromycin; CLI, clindamycin.

Figure 2 Frequency of multidrug-resistant S. aureus (MRSA and MSSA) isolates in raw (n=30) and treated (n=30) sewage samples.

Table 4 Antibiotic Resistance Genes of MSSA and MRSA Isolates in Raw and Treated Sewage Samples

Resistant Genes	MSSA			MRSA
	Positive Number [n(%)]			Positive Number [n(%)]
	Raw Sewage (n= 10)	Treated Sewage (n=10)	p value	Raw Sewage (n= 20)	Treated Sewage (n=20)	p value
mecA	1(10)	1(10)	1	20(100)	20(100)	1
vanA	1(10)	0	0.305	0	0	–
vanB	0	0	–	0	0	–
vanC	1(10)	0	0.305	3(15)	5(25)	0.429
aacA-D	1(10)	5(50)	0.051	20(100)	17(85)	0.072
tetK	3(30)	3(30)	1	19(95)	9(45)	0.001
tetM	5(50)	8(80)	0.160	9(45)	5(25)	0.185

Chabi R, Momtaz H. Virulence factors and antibiotic resistance properties of the Staphylococcus epidermidis strains isolated from hospital infections in Ahvaz, Iran. Trop Med Health. 2019;47(1):56. doi:10.1186/s41182-019-0180-731844416

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