The sensitivity of real-time PCR amplification targeting invasive Salmonella serovars in biological specimens

Background: PCR amplification for the detection of pathogens in biological material is generally considered a rapid and informative diagnostic technique. Invasive Salmonella serovars, which cause enteric fever, can be commonly cultured from the blood of infected patients. Yet, the isolation of invasive Salmonella serovars from blood is protracted and potentially insensitive. Methods: We developed and optimised a novel multiplex three colour real-time PCR assay to detect specific target sequences in the genomes of Salmonella serovars Typhi and Paratyphi A. We performed the assay on DNA extracted from blood and bone marrow samples from culture positive and negative enteric fever patients. Results: The assay was validated and demonstrated a high level of specificity and reproducibility under experimental conditions. All bone marrow samples tested positive for Salmonella, however, the sensitivity on blood samples was limited. The assay demonstrated an overall specificity of 100% (75/75) and sensitivity of 53.9% (69/128) on all biological samples. We then tested the PCR detection limit by performing bacterial counts after inoculation into blood culture bottles. Conclusions: Our findings corroborate previous clinical findings, whereby the bacterial load of S. Typhi in peripheral blood is low, often below detection by culture and, consequently, below detection by PCR. Whilst the assay may be utilised for environmental sampling or on differing biological samples, our data suggest that PCR performed directly on blood samples may be an unsuitable methodology and a potentially unachievable target for the routine diagnosis of enteric fever. </p

Enhanced Platelet Activation Mediates the Accelerated Angiogenic Switch in Mice Lacking Histidine-Rich Glycoprotein

BACKGROUND: The heparin-binding plasma protein histidine-rich glycoprotein (HRG; alternatively, HRGP/HPRG) can suppress tumor angiogenesis and growth in vitro and in vivo. Mice lacking the HRG gene are viable and fertile, but have an enhanced coagulation resulting in decreased bleeding times. In addition, the angiogenic switch is significantly enhanced in HRG-deficient mice. METHODOLOGY/PRINCIPAL FINDINGS: To address whether HRG deficiency affects tumor development, we have crossed HRG knockout mice with the RIP1-Tag2 mouse, a well established orthotopic model of multistage carcinogenesis. RIP1-Tag2 HRG(-/-) mice display significantly larger tumor volume compared to their RIP1-Tag2 HRG(+/+) littermates, supporting a role for HRG as an endogenous regulator of tumor growth. In the present study we also demonstrate that platelet activation is increased in mice lacking HRG. To address whether this elevated platelet activation contributes to the increased pathological angiogenesis in HRG-deficient mice, they were rendered thrombocytopenic before the onset of the angiogenic switch by injection of the anti-platelet antibody GP1bα. Interestingly, this treatment suppressed the increase in angiogenic neoplasias seen in HRG knockout mice. However, if GP1bα treatment was initiated at a later stage, after the onset of the angiogenic switch, no suppression of tumor growth was detected in HRG-deficient mice. CONCLUSIONS: Our data show that increased platelet activation mediates the accelerated angiogenic switch in HRG-deficient mice. Moreover, we conclude that platelets play a crucial role in the early stages of tumor development but are of less significance for tumor growth once angiogenesis has been initiated

Prostatic stromal sarcoma: A case report and literature review

Stromal sarcoma of the prostate is extremely rare. In this article, we report the case of a 43-year-old male admitted to the local hospital due to dysuria. Although the pathological findings from transurethral prostatic resection showed low-grade stromal sarcoma, the surgical specimen after radical prostatectomy revealed high-grade sarcoma with hypercellularity, marked atypical spindle cells, and high mitotic activity. This case study and literature analysis aim to emphasize its rarity and raise awareness about clinical and pathological diagnosis

Phylogeography of Diaphorina citri (Hemiptera: Liviidae) and its primary endosymbiont, 'Candidatus Carsonella ruddii’ : an evolutionary approach to host-endosymbiont interaction

BACKGROUND: In insects, little is known about the coevolution between their primary endosymbionts and hosts at the intraspecific level, and this study has examined codiversification between the notorious agricultural pest Diaphorina citri and its P‐endosymbiont, ‘Candidatus Carsonella ruddii’ at the population level. RESULTS: Maximum likelihood, haplotype network, principal components and Bayesian clustering identified three lineages for D. citri and its P‐endosymbiont: a Western clade containing individuals from Pakistan, Bhutan (Phuentsholing), Vietnam (Son La), USA, Myanmar and China (Ruili, Yunnan); a Central clade, with accessions originating from Southwest China, Bhutan (Tsirang) and Bangladesh; and an Eastern clade containing individuals from Southeast Asian countries, and East and South China. A more diverse genetic structure was apparent in the host mtDNA compared to their P‐endosymbionts; however, the two sets of data were strongly congruent. CONCLUSION: This study provides evidence for the codiversification of D. citri and its P‐endosymbiont during the invasion process from South Asia to East and Southeast Asia. We also suggested that the P‐endosymbiont may facilitate investigations into the genealogy and migration history of the host. The biogeography of D. citri and its P‐endosymbiont indicated that D. citri colonized and underwent a secondary dispersal from South Asia to East and Southeast Asia