EntE, EntS and TolC synergistically contributed to the pathogenesis of APEC strain E058.

Extraintestinal pathogenic Escherichia coli (ExPEC) shows an enhanced ability to cause infection outside the intestinal tract. Avian pathogenic E. coli (APEC), one type of ExPEC, causes avian colibacillosis, a disease of significant economic importance to poultry producers worldwide that is characterized by systemic infection. Some ExPEC strains as well as other pathogenic enterobacteria produce enterobactin, a catecholate siderophore used to sequester iron during infection. Here, we showed that disruption of enterobactin efflux via outer membrane protein TolC significantly decreased the pathogenicity of APEC strain E058. Furthermore, colonization and persistence assays performed using a chicken infection model showed that the ΔtolC mutant was obviously attenuated (p˂0.001). In contrast, disruption of enterobactin synthesis gene entE and/or the inner membrane transporter gene entS had little effect on pathogenicity. Analysis of growth kinetics revealed a significant reduction in the growth of triple mutant strain E058ΔentEΔentSΔtolC in iron-deficient medium compared with the wild-type strain (p˂0.001), while no growth impairment was noted for the E058ΔtolC mutant in either Luria-Bertani broth or iron-deficient medium. The E058ΔentEΔentSΔtolC mutant also showed significantly decreased virulence compared with single mutant strain E058ΔtolC. Low-copy complementation of strains E058ΔtolC and E058ΔentEΔentSΔtolC with plasmid-borne tolC restored virulence to wild-type levels in the chicken infection model. Macrophage infection assays showed that ingestion of E058ΔtolC by macrophage cell line HD11 cells was reduced compared with ingestion of the E058ΔentEΔentSΔtolC mutant. However, no significant differences were observed between the mutants and the wild-type in a chicken serum resistance assay. Together, these results suggest that EntE, EntS and TolC synergistically contributed to the pathogenesis of APEC strain E058 in an iron-deficient environment.

Isolation, identification, and pathogenicity of O142 avian pathogenic Escherichia coli causing black proventriculus and septicemia in broiler breeders.

Avian colibacillosis, characterized by black proventriculus and caused by avian pathogenic Escherichia coli (APEC) with an uncommon O142 serogroup, was diagnosed in young broiler breeders. Colonization and persistence assays performed in 7-day-old broilers showed that the bacterial load of the APEC 4d/9-1 O142 proventricular isolate in the lung was about 10-fold higher than that of the APEC 4d/9-1 O142 heart blood isolate (P<0.01), and about 100-fold higher in the heart blood, livers, spleens, kidneys, and proventriculi of inoculated broilers (P<0.001). When 32 common virulence genes of APEC were tested, the two isolates had nearly identical profiles, except that only the APEC 4d/9-1 O142 proventricular isolate carried the feoB gene. Furthermore, 100% mortality was observed in both 1-day-old Arbor Acres (AA) broilers and 1-day-old specific-pathogen-free (SPF) chickens inoculated with 10(6) colony-forming units of the APEC 4d/9-1 O142 proventricular isolate. However, black proventriculus was only observed in the dead AA broilers, consistent with the clinical occurrence of the disease. This implies that the black proventriculi seen in the dead birds, caused by the APEC 4d/9-1 O142 proventricular isolate, was breed-specific. Both the APEC 4d/9-1 O142 proventricular and heart blood isolates belong to phylogroup B2. However, the former was assigned to ST131 and the latter to ST2704 with multilocus sequence typing, demonstrating the genetic heterogeneity of these two bacterial isolates, although they were derived from the same dead broiler. These results suggest that the O142 APEC isolate was the main pathogenic agent for black proventriculi in 7-day-old broiler breeders.

Brain edema and protein expression of c-Fos and c-Jun in the brain after diffused brain injury.

OBJECTIVE: To investigate brain edema and protein expression of c-Fos and c-Jun in brain after diffuse brain injury, and to investigate the pathological change after brain injury, which may provide evidence for the clinical treatment of diffused brain injury. METHODS: Marmarou method was used to establish the diffuse brain injury in rats. RESULTS: After diffused brain injury, brain water content increased at 1 h, reached the peak at 1 d and remained at a high level at 7 d when compared with control group. One day after injury, diffuse subarachnoid hemorrhage was observed in the brain. HE staining showed vascular swelling and bleeding at the cortex and corpus callosum at 1 d. ß-APP expression was found at the brainstem, hippocampus, thalamus, corpus callosum and periventricular regions. Pathological examination of ultrathin sections showed evidence edema and fracture of axons at 3 d after brain injury. The brain injury caused severe cerebral ischemia. The c-Fos and c-Jun expression increased at 1 h. The c-Fos expression peaked at 3 h (P < 0.05), then reduced, reached a maximal level again at 3 d (P < 0.05), and reduced significantly at 7 d but remained at a higher level when compared with control group (P < 0.05). The number of c-Jun positive cells peaked at 6 h (P < 0.05), then reduced, reached a maximal level again at 3 d and reduced markedly but still remained at a higher level when compared with control group (P < 0.05). CONCLUSION: After diffuse brain injury, brain water content and c-Fos/c-Jun expression change over time.

Comparison on different strategies for treatments of hypertensive hemorrhage in the basal ganglia region with a volume of 25 to 35 ml.

PURPOSE: To compare curative effect of different treatments for hypertensive cerebral hemorrhage of 25 to 35 ml. METHODS: In this study, 595 cases were enrolled and grouped regarding treatments including conservative treatment, evacuation with microinvasive craniopuncture technique within 6h and 6-48 h after the attack. RESULTS: After follow up for three months after the attack, the assessment based on the Activity of Daily Living (ADL) indicated no significant difference among conservative treatment and surgical interventions (p>0.05). However, surgical interventions showed advantages of shorter hospitalization, quick removal of hematoma and obvious reduction of cost. CONCLUSION: The microinvasive craniopuncture technique to drain the hematoma within 6-48 h may be a good way in treating hypertensive hemorrhage of basal ganglia region.

Comparison on different strategies for treatments of hypertensive hemorrhage in the basal ganglia region with a volume of 25 to 35ml / Comparação de diferentes estratégias no tratamento da hemorragia hipertensiva da região dos gânglios da base com volume de 25 a 35ml

PURPOSE: To compare curative effect of different treatments for hypertensive cerebral hemorrhage of 25 to 35ml. METHODS: In this study, 595 cases were enrolled and grouped regarding treatments including conservative treatment, evacuation with microinvasive craniopuncture technique within 6h and 6-48h after the attack. RESULTS: After follow up for three months after the attack, the assessment based on the Activity of Daily Living (ADL) indicated no significant difference among conservative treatment and surgical interventions (p>0.05). However, surgical interventions showed advantages of shorter hospitalization, quick removal of hematoma and obvious reduction of cost. CONCLUSION: The microinvasive craniopuncture technique to drain the hematoma within 6-48h may be a good way in treating hypertensive hemorrhage of basal ganglia region.

OBJETIVO: Comparar o efeito curativo de diferentes tratamentos da hemorragia hipertensiva cerebral de 25 a 35ml. MÉTODOS: Foram analisados 595 casos agrupados segundo tratamento conservador e evacuação com técnica de punção transcraniana dentro de 6h ou de 6 às 48h do início do quadro clínico. RESULTADOS: O seguimento após três meses e avaliado pelo Escore de Atividade de Vida Diário, indicou que não houve diferenças significantes entre os tratamentos conservador e cirúrgico (p>0.05) O tratamento cirúrgico mostrou vantagem com hospitalização mais curta e redução de custos. CONCLUSÃO: A técnica de punção transcraniana para drenagem de hematoma dos núcleos da base pode ser uma boa alternativa de tratamento.