Bats host a broad diversity of coronaviruses (CoVs), including close relatives of human pathogens. There is only limited data on neotropical bat CoVs. We analysed faecal, blood and intestine specimens from 1562 bats sampled in Costa Rica, Panama, Ecuador and Brazil for CoVs by broad-range PCR. CoV RNA was detected in 50 bats representing nine different species, both frugivorous and insectivorous. These bat CoVs were unrelated to known human or animal pathogens, indicating an absence of recent zoonotic spill-over events. Based on RNAdependent RNA polymerase (RdRp)-based grouping units (RGUs) as a surrogate for CoV species identification, the 50 viruses represented five different alphacoronavirus RGUs and two betacoronavirus RGUs. Closely related alphacoronaviruses were detected in Carollia perspicillata and C. brevicauda across a geographical distance exceeding 5600 km. Our study expands the knowledge on CoV diversity in neotropical bats and emphasizes the association of distinct CoVs and bat host genera.

To determine possible cosavirus association with clinical disease, we used real-time reverse transcription PCR to test children and HIV-positive adults in Brazil with and without gastroenteritis. Thirteen (3.6%) of 359 children with gastroenteritis tested positive, as did 69 (33.8%) of 204 controls. Low prevalence, frequent viral co-infections, and low fecal cosavirus RNA concentrations argue against human pathogenicity.

Caseous lymphadenitis (LC) is a chronic contagious disease caused by Corynebacterium pseudotuberculosis, which mainly affects goats and sheep. Vaccination is an effective but not yet well-established method, partly due to a lack of knowledge surrounding the most effective immunoprotective components. The present study aimed to quantify and compare the in vivo expression of genes pld (phospholipase D), cpp (CP40), nanH (neuraminidase H), sodC (superoxide dismutase C) and spaC (adhesin) using qRT-PCR, with the respective expression in vitro. Caseous material of abscesses removed from five animals was cultured, with colonies suggestive of C. pseudotuberculosis identified. RNA extraction was performed on these samples, as well as on the respective pellets derived from liquid cultures brain heart infusion. After evaluating RNA integrity, complementary DNA was synthesized, followed by the relative quantification each of the genes of interest. Mean mRNA expression of the five genes found in abscesses and in cultures differed significantly, with respective values of: nanH 811.50 ± 198.27 and 359.35 ± 75.45 (p = 0.009); cpp 856.31 ± 385.11 and 154.54 ± 94.34 (p = 0.0039); plD 922.70 ± 450.73 and 212.41 ± 153.10 (p = 0.016); sodC 1,293.53 ± 564.75 and 223.63 ± 145.58 (p = 0.016); spaC 1,157.10 ± 525.13 and 214.26 ± 125.70 (p = 0,016). Expression was observed to be 6–8 times higher in abscesses than in cultures, Indicative that is a genetic expression of the in vitro bacterium exists, yet in vivo has a greater magnitude corroborating to one of these virulence factors in the pathogenesis of LC.Electronic supplementary materialThe online version of this article (10.1186/s13568-018-0598-z) contains supplementary material, which is available to authorized users.

Corynebacterium pseudotuberculosis é o agente causador da linfadenite caseosa (LC), uma doença infecciosa, granulomatosa, crônica e debilitante que acomete diversos animais, entre eles, caprinos, ovinos, bovinos, equinos, camelídeos e, mais raramente, seres humanos. O grupo denominado CMNR, composto por bactérias dos gêneros Corynebacterium, Mycobacterium, Nocardia e Rhodococcus, está envolvido em diversas patologias importantes, tanto na medicina humana quanto na veterinária. O foco dos estudos com o agente etiológico da LC tem sido em relação ao diagnóstico, epidemiologia, profilaxia, terapêutica e genômica. Embora a doença seja estudada desde o início do século XX, de forma similar àquelas causadas por outras entidades bacterianas, o levantamento acerca dos mecanismos patofisiológicos e de evasão deste agente são praticamente desconhecidos. Os fatores de virulência do agente etiológico da linfadenite caseosa são pouco numerosos, mas o sequenciamento pioneiro do genoma de uma cepa isolada de um paciente humano, C. pseudotuberculosis FRC41, permitiu a identificação e anotação de diversos genes codificadores de proteínas cujas características fisiológicas se ajustam à definição de fator de virulência. Em Mycobacterium tuberculosis, a cinase PknG controla o metabolismo da glutamina, mas pode ser secretada dentro de fagossomos de macrófagos, interferindo na maturação destas organelas. A mesma enzima existe em outros representantes da subordem Corynebacterineae, incluindo Corynebacterium pseudotuberculosis outros antígenos já foram descritos e suas estão aser elucidadas. Neste contexto, o objetivo desse trabalho foi realizar uma revisão a cerca dos fatores de virulência do C. pseudotuberculosis.