Personal non-commercial use only

ABSTRACT. Objective. To determine the epidemiology, clinical features, and microbiology of adult native joint septic arthritis in Canterbury, New Zealand, over a 5-year period in individuals with and without an underlying rheumatic disorder. Methods. Patients with native joint septic arthritis were identified retrospectively and classified by Newman's criteria. The clinical characteristics were described and comparisons made between those with and without underlying rheumatic disease. Results. Two hundred forty-eight cases of native joint septic arthritis (mean age 60, range 16-97 yrs) were identified with an overall incidence rate of 12.0/100,000/year (95% CI 10.6-13.6). Yearly incidence increased with age to a maximum of 73.4/100,000 in those > 90 years of age. Septic arthritis was iatrogenic in 16.9% of cases while 27% had an underlying inflammatory arthritis including gout (14.9%), calcium pyrophosphate disease (8.5%), and rheumatoid arthritis (4%). Few patients were taking immunosuppressant therapy, with just 1 taking a biological agent. Staphylococcus aureus was the most commonly identified organism. Those with underlying inflammatory arthritis were significantly older (73.6 yrs vs 55.6 yrs; p < 0.001), more likely to be female (55.2% vs 26.0%; p < 0.001), and to have septic polyarthritis (16.4% vs 4.4%; p = 0.002). The 30-day mortality was 2%, increasing to 6% at 90 days. Conclusion. The incidence of septic arthritis in Canterbury, New Zealand, is higher than in previous studies. Crystal arthropathy commonly coexisted with infection although autoimmune arthritis and immunosuppression was less of a factor than anticipated. (First Release November 1 2015

Personal non-commercial use only

ABSTRACT. Objective. To determine the epidemiology, clinical features, and microbiology of adult native joint septic arthritis in Canterbury, New Zealand, over a 5-year period in individuals with and without an underlying rheumatic disorder. Methods. Patients with native joint septic arthritis were identified retrospectively and classified by Newman's criteria. The clinical characteristics were described and comparisons made between those with and without underlying rheumatic disease. Results. Two hundred forty-eight cases of native joint septic arthritis (mean age 60, range 16-97 yrs) were identified with an overall incidence rate of 12.0/100,000/year (95% CI 10.6-13.6). Yearly incidence increased with age to a maximum of 73.4/100,000 in those > 90 years of age. Septic arthritis was iatrogenic in 16.9% of cases while 27% had an underlying inflammatory arthritis including gout (14.9%), calcium pyrophosphate disease (8.5%), and rheumatoid arthritis (4%). Few patients were taking immunosuppressant therapy, with just 1 taking a biological agent. Staphylococcus aureus was the most commonly identified organism. Those with underlying inflammatory arthritis were significantly older (73.6 yrs vs 55.6 yrs; p < 0.001), more likely to be female (55.2% vs 26.0%; p < 0.001), and to have septic polyarthritis (16.4% vs 4.4%; p = 0.002). The 30-day mortality was 2%, increasing to 6% at 90 days. Conclusion. The incidence of septic arthritis in Canterbury, New Zealand, is higher than in previous studies. Crystal arthropathy commonly coexisted with infection although autoimmune arthritis and immunosuppression was less of a factor tha

The Function of Hypoxia-Inducible Factor (HIF) Is Independent of the Endoplasmic Reticulum Protein OS-9

The protein “amplified in osteosarcoma-9” (OS-9) has been shown previously to interact with the prolyl hydroxylases PHD2 and PHD3. These enzymes initiate oxygen-dependent degradation of the α-subunit of hypoxia-inducible factor (HIF), a transcription factor that adapts cells to insufficient oxygen supply (hypoxia). A new model has been proposed where OS-9 triggers PHD dependent degradation of HIF-α. It was the aim of our study to define the molecular mode of action of OS-9 in the regulation of PHD and HIF activity. Although initial co-immunoprecipitation experiments confirmed physical interaction between OS-9 and PHD2, neither overexpression nor lentiviral inhibition of OS-9 expression affected HIF regulation. Subcellular localization experiments revealed a distinct reticular staining pattern for OS-9 while PHD2 was mainly localized in the cytoplasm. Further cell fractionation experiments and glycosylation tests indicated that OS-9 is a luminal ER protein. In vivo protein interaction analysis by fluorescence resonance energy transfer (FRET) showed no significant physical interaction of overexpressed PHD2-CFP and OS-9-YFP. We conclude that OS-9 plays no direct functional role in HIF degradation since physical interaction of OS-9 with oxygen sensing HIF prolyl hydroxylases cannot occur in vivo due to their different subcellular localization

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Development of improved diagnostic testing methods for invasive pneumococcal disease

Streptococcus pneumoniae (the pneumococcus) is one of the most important bacterial pathogens and contributes extensively to global infectious disease morbidity and mortality, especially in children. To unequivocally identify S. pneumoniae as the causative pathogen of diseases like pneumonia, septicaemia or meningitis, has been a challenge ever since its first description in the late 19th century, reflecting, in part, short-comings of available diagnostic tests in terms of sensitivity and specificity. In recent history pneumococcal diagnostic advances have been slow and the urine antigen test and several molecular-based techniques appear to be the sole novel diagnostic approaches over the last three decades. The focus of this study was to explore new diagnostic avenues and evaluate their usefulness in the clinical setting. The thesis starts with a landscape analysis looking at the diagnostic methods and clinician’s ordering patterns over the last 11 years, followed by the evaluation of diagnostic assays. Three methods were included in the study, namely antigen detection, polymerase chain reaction (PCR) and mass spectrometry (MS). The targets chosen for the antigen detection assays, pneumolysin (Ply) and pneumococcal surface adhesin A (PsaA) were known to be immunogenic and present in most, if not all pneumococcal serotypes. The PCR target, autolysin (lytA), though not a novel PCR target was investigated in a quantitative assay as a potential marker for disease severity. Finally, matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) MS, a technology that has been used in other areas, such as biochemistry for a few decades, has only in the last decade made advances into routine microbiological diagnostics, was explored as a tool to differentiate S. pneumoniae from related non-pneumococcal viridians streptococci. Both antigen detection assays were developed successfully. However, the Ply-assay revealed a problem with the non-specificity of the polyclonal antibody in serum specimens and was therefore not evaluated on clinical specimens. The PsaA-assay was applied to a selection of well characterised patient sera, and was showed to be specific, but needs to be of greater sensitivity to be clinically useful. The quantitative lytA PCR assay did demonstrate correlation of bacterial load and severity of disease and might be a useful adjunct in the clinical management of patients. MALDI-TOF MS is a novel tool applied to microbiological bacterial and fungal identification which needs further development in the area of typing and species level identification of certain bacteria, such as the viridians streptococci. This study demonstrated that species differentiation of S. pneumoniae from non-pneumococcal streptococci of the S. mitis group might be possible by this method. In summary, this study describes the investigation of novel diagnostic approaches which aim to provide solutions to three main ongoing challenges in the diagnosis of pneumococcal disease: (i) to increase the sensitivity of assays to detect S. pneumoniae, (ii) to differentiate between colonisation and invasive disease and (iii) to ensure more reliable identification of pneumococcal and non-pneumococcal viridians streptococci at the species level. The findings of this thesis have allowed an in depth assessment of the current state of pneumococcal diagnostics and have allowed the realistic assessment of the implementation of technologies such as antigen detection assays, quantitative PCR and mass spectrometry in this area; the latter two almost certainly will become more firmly established in the diagnosis of pneumococcal disease in future

Failure To Genotype Herpes Simplex Virus by Real-Time PCR Assay and Melting Curve Analysis Due to Sequence Variation within Probe Binding Sites

Real-time PCR with melting curve analysis of PCR products is a rapid procedure for detecting and genotyping herpes simplex virus (HSV). When testing mucocutaneous samples for HSV by a real-time PCR assay targeting the DNA polymerase gene, we found that some PCR products had atypical melting curves that did not conform to the expected melting temperatures for HSV type 1 or 2. Sequence analysis showed that these strains had base-pair mismatches over the probe binding sites. An alternative assay is required to type such atypical isolates

Fatal Case of Campylobacter lari Prosthetic Joint Infection and Bacteremia in an Immunocompetent Patient

Campylobacter lari is an infrequent cause of intestinal and extraintestinal infection in humans. We report a case of C. lari prosthetic joint infection and bacteremia in an 81-year-old immunocompetent man. The infection was associated with septic shock and fatal outcome. C. lari may cause severe disease, even in an immunocompetent host

Recurrent Breast Abscess Caused by Gordonia bronchialis in an Immunocompetent Patient

We present the first reported case of a recurrent breast infection caused by Gordonia bronchialis. The infection occurred in a 43-year-old immunocompetent female, and species level identification was obtained with 16S rRNA sequencing