Mendoza María Del Carmen, Herrero Ana, Rodicio María Rosario
Departamento de Biología Funcional, Area de Microbiología, Facultad de Medicina, Universidad de Oviedo, Oviedo, España.
Enferm Infecc Microbiol Clin. 2009 Jan;27(1):37-43. doi: 10.1016/j.eimc.2008.09.001. Epub 2009 Jan 9.
An example of evolutive engineering in bacterial pathogens is the emergence of hybrid virulence-resistance (VR) plasmids in Salmonella enterica, resulting from an association between antimicrobial resistance determinants and specific virulence plasmids of the S. typhimurium and S. choleraesuis serotypes. VR plasmids all possess the spv (Salmonella plasmid virulence) operon, which is involved in systemic infection; however, they differ in the presence of other virulence determinants and in the resistance gene profile. VR plasmids of S. typhimurium have been found in Europe, and show resistance regions with different levels of complexity that can include class 1 integrons and various transposons. VR plasmids of S. choleraesuis, detected in strains isolated in Taiwan, only confer resistance to ampicillin and sulfonamides. Both serotypes are zoonotic and the presence of hybrid VR plasmids may confer an adaptive advantage under certain conditions, resulting in bacterial strains that are more difficult to treat and have a higher epidemic potential.
细菌病原体进化工程的一个例子是肠炎沙门氏菌中出现了杂交毒力-抗性（VR）质粒，这是由抗菌抗性决定簇与鼠伤寒沙门氏菌和猪霍乱沙门氏菌血清型的特定毒力质粒之间的关联导致的。VR质粒都拥有参与全身感染的spv（沙门氏菌质粒毒力）操纵子；然而，它们在其他毒力决定因素的存在以及抗性基因谱方面存在差异。在欧洲发现了鼠伤寒沙门氏菌的VR质粒，其抗性区域的复杂程度不同，可能包括1类整合子和各种转座子。在台湾分离的菌株中检测到的猪霍乱沙门氏菌的VR质粒仅对氨苄青霉素和磺胺类药物具有抗性。这两种血清型都是人畜共患病原体，杂交VR质粒的存在可能在某些条件下赋予适应性优势，从而产生更难治疗且具有更高流行潜力的细菌菌株。
