Isolation and Identification of Staphylococcus aureus from Milk and Milk Products, Associated Factors for Contamination, and Their Antibiogram in Holeta, Central Ethiopia

Table 5

Results of logistic regression analysis of potential risk factors associated with the prevalence of Staphylococcus aureus in raw milk.

Variables	Categories	No. of tested	No. of positive (%)	Univariable		Multivariable
				OR (95% CI)	P value	OR (95% CI)	P value
Age (years)	≤5	161	12 (7.45)	1.0	—
	>5	221	21 (9.5)	1.03 (0.62–2.73)	0.483
Breed	HF cross	325	27 (8.31)	1.0	—
	Jersey	57	6 (10.53)	1.29 (0.51–3.30)	0.583
Parity	3–5	46	1 (2.17)	1.0	—	1.0
	>6	156	12 (6.79)	3.75 (0.47–29.64)	0.210	2.83 (0.32–25.18)	0.351
	1-2	180	20 (11.11)	5.62 (0.73–43.06)	0.096	6.60 (0.76–57.09)	0.086
Herd size	≥30 animals	215	18 (8.37)	1.0	—
	<30 animals	167	15 (8.98)	1.08 (0.53–2.21)	0.833
Farm hygiene	Fair	226	18 (7.96)	1.0	—
	Poor	99	9 (9.09)	1.16 (0.50–2.67)	0.735
	Good	57	6 (10.53)	1.36 (0.51–3.60)	0.536
Management system	Intensive	254	20 (7.81)	1.0
	Semi-intensive	128	13 (10.16)	1.32 (0.63–2.75)	0.457
Teat status	All normal	341	29 (8.50)	1.0	—
	At least one is blind	41	4 (9.76)	1.16 90.39–3.49)	0.788
Lactation stage	Mid (3–6 months)	130	7 (5.38)	1.0	—	1.0	—
	Late (>7 months)	98	10 (10.20)	2.0 (0.73–5.45)	0.177	1.94 (0.65–5.79)	0.236
	Early (1-2 months)	154	16 (10.39)	2.04 (0.81–5.12)	0.130	1.79 (0.65–4.87)	0.257
Milking utensils	Stainless steel	227	19 (8.37)	1.0	—
	Plastic	155	14 (9.03)	1.08 (0.53–2.24)	0.821
Method of cleaning milking containers	Hot water and detergent	58	4 (6.90)	1.0	—
	Cold water and soap/detergent	324	29 (8.95)	1.33 (0.45–3.93)	0.609
Use of disinfection	Yes	258	22 (8.53)	1.0	—
	No	124	11 (8.87)	1.04 (0.49–2.23)	0.911
The habit of fingering nose	No	24	1 (4.17)	1.0	—
	Yes	358	32 (8.94)	2.56 (0.30–17.27)	0.433
Teat washing	No	233	8 (3.43)	1.0	—	1.0	—
	Yes	149	25 (16.78)	5.67 (2.48–12.94)	≤0.001	4.93 (2.06–11.81)	≤0.001
Individual towel use	No	365	25 (6.85)	1.0		1.0
	Yes	17	8 (47.06)	12.09 (4.29–34.04)	0.001	12.13 (3.74–39.29)	≤0.001
Milking technique	Machine	106	8 (7.55)	1.0	—
	Manual	276	25 (9.06)	1.20 (0.52–2.76)	0.663
Tick infestation	No	363	27 (7.44)	1.0	—	1.0
	Yes	19	6 (31.57)	5.74 (2.02–16.31)	0.001	4.31 (1.28–14.44)	0.018

CI = confidence interval; OR = odds ratio.