食品动物源耐甲氧西林金黄色葡萄球菌MLSB类 抗生素耐药性调查

doi:10.3864/j.issn.0578-1752.2019.09.015

摘要/Abstract

摘要：

【目的】调查中国6个省食品动物源耐甲氧西林金黄色葡萄球菌（livestock-associated methicillin- resistant staphylococcus aureus,LA-MRSA）对大环内酯类-林可酰胺类-链阳菌素B类（macrolides, lincosamides and type B streptogramin, MLS_B）抗生素的耐药情况及MLS_B耐药基因的流行情况。【方法】从广东、河南、河北、福建、山东以及湖南等6省采集的食品动物源（猪、鸡以及鸭）样品约6 500份,分离金黄色葡萄球菌,通过苯唑西林药物敏感性测定和mecA,mecC基因检测鉴定MRSA菌株。采用二倍琼脂稀释法和微量肉汤稀释法测定LA-MRSA菌株对MLS_B以及其他常见的10种抗菌药物的敏感性,采用PCR方法检测MLS_B耐药基因（ermA-C和ereA-B）以及其他16种常见耐药基因。【结果】6 500份动物源样品中分离出480株金黄色葡萄球菌,其中101株为LA-MRSA,LA-MRSA分离率为1.54%（101/6500）,金黄色葡萄萄球菌中LA-MRSA检出率达21.04%（101/480）。LA-MRSA菌株对MLS_B类抗生素呈现高度耐药的情况,耐药率高达99.00%以上,对其他常见的抗菌药物氟苯尼考、四环素、头孢噻肟以及庆大霉素等抗菌药物也均呈现高度耐药,耐药率为94.00%—99.00%。MLS_B耐药基因检测结果显示,ermC的检出率最高,为100.00%;其次是ereB,为79.20%,接着是ermA和ereA,检出率分别为45.54%和40.59%,而ermB的检出率最低,为11.88%。其他耐药基因的检测结果显示fexA、tetL、aadA1、aph(4’)-Ia的检出率较高,分别是92.10%、97.02%、97.29%和83.17%;其次是tet(M),检出率为71.29%;而aac(6’)-Ib、aac(3’)-Ic、 aph(3’)-II、aph(3’)-IV、optrA、tet(A)、tet(C)的检出率相对较低,分别是49.50%、46.53%、39.60%、37.62%、33.67%、29.70%和20.79%;接着检出率更低的是cfr、tet(K)、lnuA以及lnuF,分别为17.82%、14.85%、5.94%和3.96%。进一步分析LA-MRSA菌株中MLS_B耐药基因检出个数与对受试抗菌药物的耐药数目之间的关系,发现随着动物源MRSA菌株对受试抗菌药物的耐药数目增加时,菌株中MLS_B耐药基因检出个数也在增加。【结论】动物源MRSA菌株对MLS_B高度耐药,其与菌株中ermC基因的高检出率一致,并且LA-MRSA菌株多重耐药情况严重,这与MLS_B耐药基因检出个数以及其他耐药基因的高检出率密切相关。因此,养殖场中MLS_B类药物使用应规范使用,以减少动物源MRSA菌株的多重耐药性。

关键词: 食品动物源, LA-MRSA, MLS_B, erm, 多重耐药

Abstract:

【Objective】 The aim of this study was to investigate the prevalence of genes encoding resistance to macrolides, lincosamides and streptogramins (MLS_B) among methicillin-resistant Staphylococcus aureus from food animals in China. 【Method】Staphylococcus aureus were isolated from about 6 500 samples of pig, chicken and duck origins among six different provinces, including Guangdong, Henan, Hebei, Fujian and so on, in China. LA-MRSA was confirmed from staphylococcus aureus through detecting the susceptibility of oxacillin and the presence of mecA and mecC genes. Susceptibility test of LA-MRSA resistant to MLS_B and other common antibiotics were determined by agar dilution method and microdilution broth method. And the MLS_B resistance genes (ermA-C and ereA-B) and other common resistant genes were detected by PCR. 【Result】Four hundred and eighty Staphylococcus aureus isolates and 101 LA-MRSA isolates were found among about 6 500 samples, and the isolation rate of Staphylococcus aureus and the detection rate of LA-MRSA among Staphylococcus aureus isolates were 1.54% (101/6500) and 21.04% (101/480), respectively. Susceptibility test showed high resistance rate of LA-MRSA to MLS_B was found with over 99.00% among LA-MRSA isolates. High resistance rate to other common antibiotics was also found among LA-MRSA, including florfenicol, tetracycline, cefotaxime and gentamycin with the resistance rates of 99.01%, 96.39%, 96.39%, 96.39% and 94.05%, respectively. MLS_B resistance genes detection showed that ermC was found in all LA-MRSA isolates, followed by ereB (79.20%), ermA (45.54%) and ereA (40.59%), while, ermB was present with a low detection rate (11.88%). Other drug-resistant genes test results showed that fexA, tetL, aadA1, aph (4') - Ia detection rate was higher, which was 92.10%, 97.02%, 97.29% and 83.17%, respectively; secondly, tet (M), the detection rate was 71.29%; the detection rate of aac (6') - Ib, aac (3') - Ic, aph (3') -II, aph (3') -IV, optrA, tet (A) and tet (C) was relatively low, which was 49.50%, 46.53%, 39.60%, 37.62%, 33.67%, 29.70% and 20.79%, respectively; the detection rate of cfr, tet (K), lnuA and lnuF was the lowest, which was 17.82%, 14.85%, 5.94% and 3.96%, respectively. The relationship of the number of MLS_B resistance genes and the number of resistance to antibiotics was further analyzed, which indicated the increased number of resistance to antibiotics was corresponding with the increased number of MLS_B resistance genes and high detection rate of other resistant genes among the LA-MRSA isolates. 【Conclusion】In conclusion, in this study, a high resistance to MLS_B was found and it was consistent to the high detection rate of ermC gene among LA-MRSA isolates. The multi-drug resistance of LA-MRSA isolates was serious and this was closely related to the number of MLS_B resistance genes. Therefore, it is urgently needed to take action in the rational use of antibiotics, as to reducing the emergence of multi-drug resistance LA-MRSA.

Key words: food animal, LA-MRSA, MLS_B, erm, multidrug resistance

李淑敏, 方亮星, 李亮, 赵孟, 陆肖, 古伟琪, 廖晓萍, 孙坚, 熊雁琼, 刘雅红. 食品动物源耐甲氧西林金黄色葡萄球菌MLS_B类抗生素耐药性调查[J]. 中国农业科学, 2019, 52(9): 1646-1656.

LI ShuMin, FANG LiangXing, LI Liang, ZHAO Meng, LU Xiao, GU WeiQi, LIAO XiaoPing, SUN Jian, XIONG YanQiong, LIU YaHong. Investigation on the Antibiotic Resistance of Staphylococcus Methicillin-Resistant MLS_B from Food Animals in Six Provinces of China[J]. Scientia Agricultura Sinica, 2019, 52(9): 1646-1656.

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参考文献 43

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基因名称Genes’ name	引物序列（5′→3′）Primer sequence	片段长度Size (bp)	t_退火 (℃)	参考文献Reference
mecA	F: AAAATCGATGGTAAAGGTTGGC R: AGTTCTGCAGTACCGGATTTGC	533	58	[22]
mecC	F:4GAAAAAAAGGCTTAGAACGCCTC R:GAAGATCTTTTCCGTTTTCAGC	137	58	[23]
ermA	F: GTTCAAGAACAATCAATACAGAG	421	52	[24]
ermA	R: GGATCAGGAAAAGGACATTTTAC	421	52
ermB	F:CCGTTTACGAAATTGGAACAGGTAAAGGGC	359	55	[24]
ermB	R: GAATCGAGAC TTGAGTGTGC	359	55
ermC	F: GCTAATATTG TTTAAATCGT CAATTCC	572	52	[25]
ermC	R: GGATCAGGAA AAGGACATTT TAC	572	52
ereA	F: AACACCCTGAACCCAAGGGACG	420	50	[26]
ereA	R: CTTCACATCCGGATTCGCTCGA	420	50
ereB	F: AGAAATGGAGGTTCATACTTACCA	546	50	[26]
ereB	R: CATATAATCATCACCAATGGCA	546	50

样品来源 Source		样品数 Number	金黄色葡萄球菌数(株) Number of Staphylococcus aureus	MRSA菌株数(株) Number of MRSA	样品中MRSA菌株的分离率 The separation rate of MRSA (%)	金黄色葡萄球菌中 MRSA菌的检出率 The separation rate of Staphylococcus aureus (%)
猪源Pig	粪便Faeces	3020	177	40	1.32%	22.59%
猪源Pig	鼻拭子Nose swab	480	104	36	7.50%	34.60%
鸡源Chicken	盲肠Cecum	1546	109	14	0.91%	12.84%
	肝脏Liver	654	48	6	0.92%	12.50%
鸭源Duck	盲肠Cecum	436	24	3	0.69%	12.50%
鸭源Duck	肝脏Liver	364	18	2	0.55	11.1%
总数Total		6500	480	101	1.55%	21.04%

对抗菌药物耐药的数目 Number	2	6	7	9	10	11	12
菌株数（株）The number of strain	1	1	2	3	35	48	11
百分率Percentage (%)	0.98	0.98	1.98	3.96	34.65	47.52	10.89

多重耐药（菌株数） Multi-drug (Number of strain)	基因组合 Assortment of genes	菌株数 The number of strain	携带相同个数耐药基因所占比例 Percentage (%)
12耐（11）	ermC-ereB-ermA-ermB-ereA	1	1（9.09%）
	ermC-ereB-ermA-ermB	2	5（45.45%）
	ermC-ereB-ermA-ereA	2
	ermC-ereB-ermB-ereA	1
	ermC-ereB-ermA	4	4（36.36%）
	ermC-ereB	1	1（9.09%）
11耐（48）	ermC-ereB-ermA-ereA	11	11（22.92%）
	ermC-ereB-ereA	6	17（35.42%）
	ermC-ereB-ermA	9
	ermC-ereB-ermB	1
	ermC-ereA-ermA	1
	ermC-ereB	11	19（39.58%）
	ermC-ermA	5
	ermC-ereA	3
	ermC	2	2（4.17%）
10耐（35）	ermC-ereB-ermA-ereA	3	7（20.00%）
	ermC-ereB-ermA-ermB	4	7（20.00%）
	ermC-ermB-ermA	2	15（42.86%）
	ermC-ereB-ereA	4
	ermC-ereB-ermA	8
	ermC-ereA-ermA	1
	ermC-ereB	7	9（25.71%）
	ermC-ermB	2	9（25.71%）
	ermC	4	4（11.43%）
9耐（3）	ermC-ereB-ereA	1	1(33.33%)
	ermC-ereA	1	2(66.67%)
	ermC-ereB	1	2(66.67%)
7耐（2）	ermC-ereB-ermA-ermB	1	1(50.00%)
7耐（2）	ermC-ermA	1	1(50.00%)
6耐（1）	ermC-ereB	1	1(100.00%)
2耐（1）	ermC-ereB-ereA	1	1(100.00%)