RESUMEN
Modified-live virus (MLV) vaccines derived from highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) were wildly used in China, which resulted in the emergence of MLV-like strains in pigs. Previous studies demonstrated that secondary bacterial infection could enhance HP-PRRSV infection-mediated inflammatory responses, but it is unknown whether early bacterial infection could enhance the HP-PRRSV MLV-like infection-mediated pathological reaction. In this paper, to gain the evidence for infection of pigs with MLV-like strains in China, we firstly analyzed the genetic characterization of the HP-PRRSV MLV-like isolate (TJxq1701) and further evaluated whether the early Streptococcus suis infection synergizes HP-PRRSV MLV-like infection-mediated pathological reaction. Our results showed that the whole genome of TJxq1701 shared the highest homology with JXA1-P80 and a total of 16 amino acids residues unique to JXA1-P80 in ORF1a, ORF1b, GP2, GP3, GP4, and GP5 were found in the corresponding locations. The results of infection experiments in pigs revealed that TJxq1701 caused transitional fever, moderate respiratory clinical sign and microscopic lung lesions in piglets, but early infection with low virulence Streptococcus suis serotype 2 (SS2) exhibited seriously clinical signs, including high fever, anorexia, and respiratory distress, leading to 60% mortality within four weeks in comparison with alone infected group. Taken together, our findings reveal that early bacterial infection could enhance the HP-PRRSV MLV-like infection-mediated pathological reaction, which provide an important clue for understanding that streptococcus infection increases the pathogenicity of MLV-like virus and a new thought for prevention and control of PRRSV.
Asunto(s)
Síndrome Respiratorio y de la Reproducción Porcina/virología , Virus del Síndrome Respiratorio y Reproductivo Porcino/fisiología , Virus del Síndrome Respiratorio y Reproductivo Porcino/patogenicidad , Infecciones Estreptocócicas/veterinaria , Streptococcus suis/fisiología , Enfermedades de los Porcinos/virología , Animales , Serogrupo , Infecciones Estreptocócicas/microbiología , Streptococcus suis/genética , Porcinos , Enfermedades de los Porcinos/microbiología , Vacunas Atenuadas , VirulenciaRESUMEN
Objective To investigate the clinical significance of procalcitonin(PCT)and serum amyloid A (SAA)in early bacterial infection in preschool children.Methods 67 children with bacterial infection(bacte-rial infection group),62 children with viral infection(viral infection group)and 60 healthy children(healthy control group)were enrolled in this study,latex enhanced turbidimetric immunoassay was used to detect SAA and turbidimetric immunoassay was used to detect the level of PCT,the levels of SAA and PCT and the posi-tive rate were compared among all groups,and the sensitivity,specificity and positive predictive value,negative predictive value and Youden index of SAA and PCT levels.Results The levels of SAA and PCT in the bacte-rial infection group before treatment were significantly higher than those in the viral infection group and the healthy control group(P<0.05),7 days after treatment,the levels of SAA and PCT decreased significantly (P<0.05);the level of PCT in viral infection group was not significantly different from that in healthy control group(P>0.05),but the positive rate of SAA was significantly different from that of the healthy control group(P<0.05).The sensitivity,specificity,positive predictive value and negative predictive value of PCT for early bacterial infection in preschool children were 92.5%,93.5%,93.9%,92.1%,respectively,of the SAA values were 97.0%,59.7%,72.2% and 94.9%,respectively,there were significant differences between the two groups in specificity and positive predictive value(P<0.05).Conclusion Detection of SAA and PCT lev-els was helpful for early diagnosis,differential diagnosis and prognosis of bacterial infection in preschool chil-dren.
RESUMEN
Objective To explore the clinical diagnostic value of CD64 index of neutrophil and serum amy-loid A(SAA)in early bacterial infections of children with respiratory tract.Methods A total of 152 children with respiratory tract infection admitted to Xianning Central Hospital from January 2017 to December 2017 were retrospectively analyzed.According to whether the pathogens were isolated,they were divided into 84 ca-ses of bacterial infection group and 68 cases of suspected respiratory tract infection group,at the same time,50 cases of healthy children in the same period were selected as the control group,the level of CD64 and SAA in three groups of patients was compared and analyzed,and the sensitivity,specificity,positive predictive value and negative predictive value of CD64 and SAA for the diagnosis of bacterial infection were also analyzed.Re-sults The CD64 index and SAA level in the bacterial infection group were higher than those of the suspected respiratory infection group(P< 0.05),after effective treatment,the two were significantly decreased(P<0.05).T he sensitivity,specificity,positive predictive value and negative predictive value of CD 64 index in diag-nosing bacterial infection were 92.9%,98.0%,98.7% and 89.1%,respectively,SAA was 96.4%,96.0%, 97.6% and 94.1%,respectively.Conclusion The detection of CD64 index and SAA level can help the early diagnosis,differential diagnosis and prognosis evaluation of respiratory tract bacterial infection in children, which is worthy of clinical promotion.