摘要
城市污泥中含有大量肠球菌,可携带抗生素抗性基因(antibiotic resistance genes,ARGs)和毒力基因(virulence gene,VGs),从而具有潜在的耐药性和致病性,对人类健康存在巨大威胁.为此考察了热水解污泥在中温(40℃)/高温(55℃)厌氧消化过程中肠球菌的耐药表型、基因型及携带VGs的变化规律.结果表明,厌氧进泥中肠球菌对阿奇霉素的耐药率均显著高于螺旋霉素和四环素.高温厌氧对肠球菌的数量及耐药性具有更好地控制及削减效果.高温厌氧消化可能会促进四环素类抗性基因在肠球菌的表达.中温、高温厌氧消化可促进ARGs在肠球菌中发生水平转移,导致其潜在双重甚至多重耐药性增加.中温厌氧消化可降低肠球菌同时具有潜在致病性和耐药性的几率,而高温厌氧消化则会增加此风险.
Municipal sludge contains large amounts of enterococci,which can harbor antibiotic resistance genes( ARGs) and virulence genes( VGs). ARG-and VG-containing enterococci therefore present potential resistance and virulence and,as a consequence,represent a significant health risk to humans. Therefore,the resistance phenotype of enterococci and the prevalence of ARGs and VGs in the enterococci isolated from the mesophilic( 40℃) and thermophilic( 55℃) anaerobic digestion of thermal hydrolyzed sludge was investigated. Results showed that the enterococci isolated from thermal hydrolyzed sludge showed significantly higher resistance to azithromycin than that to spiramycin and tetracycline. Thermophilic anaerobic digestion resulted in a greater reduction of enterococci abundance( by two orders of magnitude and one order of magnitude,respectively),and a greater reduction in the antibiotic resistance rates of the enterococci. However,thermophilic digestion can promote the expression of tetracycline resistance genes in the enterococci.Furthermore,both mesophilic and thermophilic digestion can facilitate horizontal genes transfer( HGT) between enterococci,which might result in an increase in the occurrence of double-or multiple-resistance. Mesophilic digestion reduced the prevalence of cooccurring ARGs and VGs in enterococci,while thermophilic digestion had the opposite effect. This research improves understanding of the occurrence and fate of ARGs and VGs in potential pathogens during the treatment of municipal sludge.
引文
[1] Anderson A C,Jonas D,Huber I,et al. Enterococcus faecalis from food, clinical specimens, and oral sites:prevalence of virulence factors in association with biofilm formation[J].Frontiers in Microbiology,2016,6:1534.
[2] Talebi M,Asghari Moghadam N,Mamooii Z,et al. Antibiotic resistance and biofilm formation of enterococcus faecalis in patient and environmental samples[J]. Jundishapur Journal of Microbiology,2015,8(10):e23348.
[3]张肖肖,马传玲,刘海洋,等.临床分离肠球菌生物膜的形成能力及毒力基因的相关性研究[J].中国抗生素杂志,2016,41(11):869-873.Zhang X X,Ma C L,Liu H Y,et al. The ability of biofilm formation in clinical Enterococcus and their correlation with virulence factors[J]. Chinese Journal of Antibiotics,2016,41(11):869-873.
[4]张慧,叶丹娟,何晴,等.人和鸡来源粪肠球菌耐药性以及毒力基因分布研究[J].现代预防医学,2014,41(14):2611-2613,2616.Zhang H,Ye D J,He Q,et al. Study on drug resistance and gene distribution of virulent factors in Enterococcus faecalis from human and chicken[J]. Modern Preventive Medicine,2014,41(14):2611-2613,2616.
[5]陈丽颖,张留君,秦明明,等.不同动物源肠球菌耐药性及毒力基因测定与分析[J].中国人兽共患病学报,2017,33(11):984-990.Chen L Y,Zhang L J,Qin M M,et al. Drug resistance spectrum and virulence gene distribution in Enterococcus isolates of animal origin[J]. Chinese Journal of Zoonoses,2017,33(11):984-990.
[6] Lanthier M,Scott A,Lapen D R,et al. Frequency of virulence genes and antibiotic resistances in Enterococcus spp. isolates from wastewater and feces of domesticated mammals and birds,and wildlife[J]. Canadian Journal of Microbiology,2010,56(9):715-729.
[7] Rad P K,Eslami G. Distribution of gel E,esp and hyl virulence genes among enteroccus facium isolated from urban sewage samples intehran[J]. Iranian Journal of Public Health,2014,(43):122.
[8] Da Costa P M, Vaz-Pires P, Bernardo F. Antimicrobial resistance in Enterococcus spp. isolated in inflow,effluent and sludge from municipal sewage water treatment plants[J]. Water Research,2006,40(8):1735-1740.
[9] Tong J,Lu X T,Zhang J Y,et al. Occurrence of antibiotic resistance genes and mobile genetic elements in enterococci and genomic DNA during anaerobic digestion of pharmaceutical waste sludge with different pretreatments[J]. Bioresource Technology,2017,235:316-324.
[10] Da Silva G J,Mendona N. Association between antimicrobial resistance and virulence in Escherichia coli[J]. Virulence,2012,3(1):18-28.
[11] Soto S M. Relationship between virulence and antimicrobial resistance in bacteria[J]. Reviews in Medical Microbiology,2009,20(4):84-90.
[12] Da Silva M F,Tiago I,Veríssimo A,et al. Antibiotic resistance of enterococci and related bacteria in an urban wastewater treatment plant[J]. FEMS Microbiology Ecology,2006,55(2):322-329.
[13]国家环境保护总局.水和废水监测分析方法[M].(第四版).北京:中国环境科学出版社,2002.
[14] M100-S24,Performance standards for antimicrobial susceptibility testing; Twenty-fourth informational supplement[S].
[15] Zhang J Y,Chen M X,Sui Q W,et al. Fate of antibiotic resistance genes and its drivers during anaerobic co-digestion of food waste and sewage sludge based on microwave pretreatment[J]. Bioresource Technology,2016,217:28-36.
[16] Tong J,Liu J B,Zheng X,et al. Fate of antibiotic resistance bacteria and genes during enhanced anaerobic digestion of sewage sludge by microwave pretreatment[J]. Bioresource Technology,2016,217:37-43.
[17] Kwon K H,Hwang S Y,Moon B Y,et al. Occurrence of antimicrobial resistance and virulence genes,and distribution of enterococcal clonal complex 17 from animals and human beings in Korea[J]. Journal of Veterinary Diagnostic Investigation,2012,24(5):924-931.
[18] Meena B,Anburajan L,Sathish T,et al. Enterococcus species diversity and molecular characterization of biomarker genes in Enterococcus faecalis in Port Blair Bay,Andaman and Nicobar Islands,India[J]. Marine Pollution Bulletin,2015,94(1-2):217-227.
[19] Vankerckhoven V, Van Autgaerden T, Vael C, et al.Development of a multiplex PCR for the detection of asa1,gelE,cyl A,esp,and hyl genes in enterococci and survey for virulence determinants among european hospital isolates of Enterococcus faecium[J]. Journal of Clinical Microbiology,2004,42(10):4473-4479.
[20]刘和,符波,姜谦,等.城市剩余污泥厌氧消化对病原微生物的杀灭机理研究[A].见:第十五次全国环境微生物学学术研讨会论文集[C].大连:中国微生物学会,2012.
[21] Roberts A P,Mullany P. Tn916-like genetic elements:a diverse group of modular mobile elements conferring antibiotic resistance[J]. FEMS Microbiology Reviews,2011,35(5):856-871.
[22] Hegstad K,Mikalsen T,Coque T M,et al. Mobile genetic elements and their contribution to the emergence of antimicrobial resistant Enterococcus faecalis and Enterococcus faecium[J].Clinical Microbiology and Infection,2010,16(6):541-554.
[23] Molale L G,Bezuidenhout C C. Antibiotic resistance,efflux pump genes and virulence determinants in Enterococcus spp. from surface water systems[J]. Environmental Science and Pollution Research,2016,23(21):21501-21510.
[24] Sidhu J P S, Skelly E, Hodgers L, et al. Prevalence of Enterococcus species and their virulence genes in fresh water prior to and after storm events[J]. Environmental Science&Technology,2014,48(5):2979-2988.
[25] De Souza Carneiro C,Evangelista-Barreto N S,Da SilveiraOliveira C S, et al. Antagonistic activity, antimicrobial susceptibility and potential virulence factors of Enterococcus faecalis[J]. Journal of Life Sciences,2015,9:318-326.
[26] Hammad A M, Hassan H A, Shimamoto T. Prevalence,antibiotic resistance and virulence of Enterococcus spp. in Egyptian fresh raw milk cheese[J]. Food Control,2015,50:815-820.
[27] DuprèI,Zanetti S,Schito A M,et al. Incidence of virulence determinants in clinical Enterococcus faecium and Enterococcus faecalis isolates collected in Sardinia(Italy)[J]. Journal of Medical Microbiology,2003,52:491-498.