In Situ Localization of Staphylococcus shinii and Staphylococcus succinus in Infected Rhipicephalus microplus Ticks: Implications for Biocontrol Strategies

<i>Rhipicephalus microplus</i> is a blood-sucking parasite that causes heavy infestations on cattle and is a vector for severe tick-borne diseases, such as anaplasmosis and babesiosis, and poses a significant threat to the cattle industry. Cattle ticks show increasing acaricide resistance, which creates an additional problem concerning the inefficient chemical control of tick populations in cattle-grazing areas, necessitating the exploration of alternative tick biocontrol methods. Our study aimed to demonstrate the acaropathogenic efficacy of two bacterial species during experimental infections on <i>R. microplus</i>. Our experimental data confirmed that <i>S. shinii</i> and <i>S. succinus</i> exhibited significant acaropathogenic properties against <i>R. microplus,</i> as demonstrated by the tracking of fluorescent-labeled bacteria within the engorged-tick body. Our experiments revealed that both bacterial species could infect the hemolymph, salivary glands, and vestibular vagina of the tick, inducing histological changes in the affected organs that may impair feeding as well as reproductive capabilities. Gené's organ infection was detected only in <i>S. succinus</i>. Our findings offer valuable insights for developing biocontrol strategies to manage <i>Rhipicephalus microplus</i> populations effectively.