Table 2.

Numbers of isolates of P. multocida and other pathogens detected in 3212 lung samples from pigs collected between February 2011 and October 2015

Year	No. of sample	No. of P. multocida	Isolation rates(%)a	Pathogens co-infected with P. multocida
				S.suis	HPS	E. coli	Bb	Salmonella	Others
2011	616	46	7.5	15	13	8	3	2	2
2012	570	61	10.7	20	17	11	4	2	4
2013	630	57	9.0	19	15	11	6	1	3
2014	754	72	9.6	22	17	12	7	3	6
2015	642	60	9.3	18	14	11	6	2	4
Total	3212	296	9.2	94	76	53	26	10	19
				(48.7%)	(39.3%)	(27.5%)	(13.5%)	(5.1%)	(9.8%)

^aThere were no significant differences in the annual isolates rates of P. multocida between 2011 and 2015 (p > 0.05). Statistical analysis was performed using the χ ² test. S. suis, HPS, E. coli, and Bb represent Streptococcus suis, Haemophilus parasuis, Escherichia coli and Bordetella bronchiseptica, respectively