Antibiotic profiling of Methicillin Resistant Staphylococcus aureus (MRSA) isolates in stray canines and felines

Figures & data

Table 1. Antibiotics, solvent and amount impregnated per disk

Antibiotic	Solvent	Disc potency (μg)	Inhibition zone size (mm)
			R	I	S
Ceftazidime^a	Distilled water	30	≤14	15–17	≥18
Enrofloxacin^b	Distilled water	5	<22	-	≥22
Methicillin^a	Distilled water	5	≤9	10–13	≥14
Oxacillin^a	Distilled water	1	≤10	10–12	≥13
Vancomycin^a	Distilled water	30	-	-	≥15

Notes: R = Resistant; I = Intermediate; S = Susceptible.

^a Classification adapted from National Committee for Clinical Laboratory Standard (2001).

^b Classification adapted from Attili et al. (2016).

Table 2. The resistance classification for 33 MRSA isolated from canines

Antibiotic	No. of isolates
	R	I	S
Ceftazidime^a	27	2	4
Enrofloxacin^b	26	0	7
Methicillin^a	33	0	0
Oxacillin^a	20	2	11
Vancomycin^a	0	0	33

Notes: R = Resistant; I = Intermediate; S = Susceptible.

^a Classification adapted from National Committee for Clinical Laboratory Standard (2001).

^b Classification adapted from Attili et al. (2016).

Table 3. The resistance classification for 13 MRSA isolated from felines

Antibiotic	No. of isolates
	R	I	S
Ceftazidime^a	13	0	0
Enrofloxacin^b	12	0	1
Methicillin^a	13	0	0
Oxacillin^a	11	0	2
Vancomycin^a	0	0	13

Notes: R = Resistant; I = Intermediate; S = Susceptible.

^a Classification adapted from National Committee for Clinical Laboratory Standard (2001).

^b Classification adapted from Attili et al. (2016).

Figure 1. Antibiotic resistance profile for 33 canine (A) and 13 feline (B) MRSA isolates based on level of resistance towards different antibiotics in percentage.

Notes: Colour codes – Golden yellow = resistant, Sky-blue = intermediate Pear-green = Susceptible.

Figure 2. Resistance of the 33 canine (A) and 13 feline (B) MRSA isolates to number of antibiotics.

Figure 3. Boxplots of antibiotics resistance profiles, which are measured by inhibition zone (mm), of canine and feline isolates.

Notes: Values in the boxplots below the dashed red lines indicate resistance for the particular antibiotic.

Figure 4. Principal components analysis plot of canine and feline isolates as groups and the four antibiotics, ceftazidime, enrofloxacin, oxacillin and vancomycin, as variables.

Notes: The actual values for the antibiotic variables are derived from the inhibition zone measurements (mm) for all isolates. The antibiotic methicillin is not included because all samples are resistant to it.

National Committee for Clinical Laboratory Standard. (2001). Performance standards for antimicrobial disc susceptibility tests (M2-A7 and M7-A5) (6th ed., Vol. 21, No. 1). 11th informational supplement 2001 (M100-S11), 1997.

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