Modifiable risk factors for multidrug-resistant Gram-negative infection in critically ill burn patients: a systematic review and meta-analysis.

BACKGROUND: We conducted a systematic review and meta-analysis to identify potentially modifiable risk factors for multidrug-resistant Gram-negative colonization or infection in critically ill burn patients. METHODS: A systematic search was conducted of PubMed, Embase, CINAHL, Web of Science and Central (Cochrane). Risk factors including antibiotic use and hospital interventions were summarized in a random-effects meta-analysis. Risk of publication bias was assessed using the Grading of Recommendations Assessment, Development and Evaluation method and funnel plots. RESULTS: A total of 11 studies met the inclusion criteria. We identified several potentially modifiable risk factors and were able to grade their importance based on effect size. Related to prior antibiotic exposure, extended-spectrum cephalosporins (pooled odds ratio (OR) 7.00, 95% confidence interval (CI) 2.77-17.67), carbapenems (pooled OR 6.65, 95% CI 3.49-12.69), anti-pseudomonal penicillins (pooled OR 4.23, 95% CI 1.23-14.61) and aminoglycosides (pooled OR 4.20, 95% CI 2.10-8.39) were most significant. Related to hospital intervention, urinary catheters (pooled OR 11.76, 95% CI 5.03-27.51), arterial catheters (pooled OR 8.99, 95% CI 3.84-21.04), mechanical ventilation (pooled OR 5.49, 95% CI 2.59-11.63), central venous catheters (pooled OR 4.26, 95% CI 1.03-17.59), transfusion or blood product administration (pooled OR 4.19, 95% CI 1.48-11.89) and hydrotherapy (pooled OR 3.29, 95% CI 1.64-6.63) were most significant. CONCLUSION: Prior exposure to extended-spectrum cephalosporins and carbapenems, as well as the use of urinary catheters and arterial catheters pose the greatest threat for infection or colonization with multidrug-resistant Gram-negative organisms in the critically ill burn patient population.

Disease surveillance based on Internet-based linear models: an Australian case study of previously unmodeled infection diseases.

Effective disease surveillance is critical to the functioning of health systems. Traditional approaches are, however, limited in their ability to deliver timely information. Internet-based surveillance systems are a promising approach that may circumvent many of the limitations of traditional health surveillance systems and provide more intelligence on cases of infection, including cases from those that do not use the healthcare system. Infectious disease surveillance systems built on Internet search metrics have been shown to produce accurate estimates of disease weeks before traditional systems and are an economically attractive approach to surveillance; they are, however, also prone to error under certain circumstances. This study sought to explore previously unmodeled diseases by investigating the link between Google Trends search metrics and Australian weekly notification data. We propose using four alternative disease modelling strategies based on linear models that studied the length of the training period used for model construction, determined the most appropriate lag for search metrics, used wavelet transformation for denoising data and enabled the identification of key search queries for each disease. Out of the twenty-four diseases assessed with Australian data, our nowcasting results highlighted promise for two diseases of international concern, Ross River virus and pneumococcal disease.

Using Baidu Search Index to Predict Dengue Outbreak in China.

This study identified the possible threshold to predict dengue fever (DF) outbreaks using Baidu Search Index (BSI). Time-series classification and regression tree models based on BSI were used to develop a predictive model for DF outbreak in Guangzhou and Zhongshan, China. In the regression tree models, the mean autochthonous DF incidence rate increased approximately 30-fold in Guangzhou when the weekly BSI for DF at the lagged moving average of 1-3 weeks was more than 382. When the weekly BSI for DF at the lagged moving average of 1-5 weeks was more than 91.8, there was approximately 9-fold increase of the mean autochthonous DF incidence rate in Zhongshan. In the classification tree models, the results showed that when the weekly BSI for DF at the lagged moving average of 1-3 weeks was more than 99.3, there was 89.28% chance of DF outbreak in Guangzhou, while, in Zhongshan, when the weekly BSI for DF at the lagged moving average of 1-5 weeks was more than 68.1, the chance of DF outbreak rose up to 100%. The study indicated that less cost internet-based surveillance systems can be the valuable complement to traditional DF surveillance in China.

Porphyromonas loveana sp. nov., isolated from the oral cavity of Australian marsupials.

An obligatory anaerobic, Gram-stain-negative coccobacillus with black-pigmented colonies was isolated from the oral cavity of selected Australian marsupial species. Phenotypic and molecular criteria showed that this bacterium was a distinct species within the genus Porphyromonas, and was closely related to Porphyromonas gingivalis and Porphyromonas gulae. This putative novel species and P. gulae could be differentiated from P. gingivalis by catalase activity. Further characterization by multi-locus enzyme electrophoresis of glutamate dehydrogenase and malate dehydrogenase enzyme mobility and matrix-assisted laser desorption ionization time-of-flight MS showed that this putative novel species could be differentiated phenotypically from P. gingivalis and P. gulae. Definitive identification by 16S rRNA gene sequencing showed that this bacterium belonged to a unique monophyletic lineage, phylogenetically distinct from P. gingivalis (94.9 % similarity) and P. gulae (95.5 %). This also was supported by 16S-23S rRNA intergenic spacer region and glutamate dehydrogenase gene sequencing. A new species epithet, Porphyromonas loveana sp. nov., is proposed for this bacterium, with DSM 28520T (=NCTC 13658T=UQD444T=MRK101T), isolated from a musky rat kangaroo, as the type strain.

Use of big data in the surveillance of veterinary diseases: early detection of tick paralysis in companion animals.

BACKGROUND: Tick paralysis, resultant from envenomation by the scrub-tick Ixodes holocyclus, is a serious threat for small companion animals in the eastern coast of Australia. We hypothesise that surveillance systems that are built on Internet search queries may provide a more timely indication of high-risk periods more effectively than current approaches. METHODS: Monthly tick paralysis notifications in dogs and cats across Australia and the states of Queensland (QLD) and New South Wales (NSW) were retrieved from Disease WatchDog surveillance system for the period 2011-2013. Internet search terms related to tick paralysis in small companion animals were identified using Google Correlate, and corresponding search frequency metrics were downloaded from Google Trends. Spearman's rank correlations and time series cross correlations were performed to assess which Google search terms lead or are synchronous with tick paralysis notifications. RESULTS: Metrics data were available for 24 relevant search terms at national level, 16 for QLD and 18 for NSW, and they were all significantly correlated with tick paralysis notifications (P < 0.05). Among those terms, 70.8, 56.3 and 50 % showed strong Spearman's correlations, at national level, for QLD, and for NSW respectively, and cross correlation analyses identified searches which lead notifications at national or state levels. CONCLUSION: This study demonstrates that Internet search metrics can be used to monitor the occurrence of tick paralysis in companion animals, which would facilitate early detection of high-risk periods for tick paralysis cases. This study constitutes the first application of the rapidly emerging field of Internet-based surveillance to veterinary science.

Heterogeneous and Dynamic Prevalence of Asymptomatic Influenza Virus Infections.

Influenza infection manifests in a wide spectrum of severity, including symptomless pathogen carriers. We conducted a systematic review and meta-analysis of 55 studies to elucidate the proportional representation of these asymptomatic infected persons. We observed extensive heterogeneity among these studies. The prevalence of asymptomatic carriage (total absence of symptoms) ranged from 5.2% to 35.5% and subclinical cases (illness that did not meet the criteria for acute respiratory or influenza-like illness) from 25.4% to 61.8%. Statistical analysis showed that the heterogeneity could not be explained by the type of influenza, the laboratory tests used to detect the virus, the year of the study, or the location of the study. Projections of infection spread and strategies for disease control require that we identify the proportional representation of these insidious spreaders early on in the emergence of new influenza subtypes or strains and track how this rate evolves over time and space.

Internet-based surveillance systems for monitoring emerging infectious diseases.

Emerging infectious diseases present a complex challenge to public health officials and governments; these challenges have been compounded by rapidly shifting patterns of human behaviour and globalisation. The increase in emerging infectious diseases has led to calls for new technologies and approaches for detection, tracking, reporting, and response. Internet-based surveillance systems offer a novel and developing means of monitoring conditions of public health concern, including emerging infectious diseases. We review studies that have exploited internet use and search trends to monitor two such diseases: influenza and dengue. Internet-based surveillance systems have good congruence with traditional surveillance approaches. Additionally, internet-based approaches are logistically and economically appealing. However, they do not have the capacity to replace traditional surveillance systems; they should not be viewed as an alternative, but rather an extension. Future research should focus on using data generated through internet-based surveillance and response systems to bolster the capacity of traditional surveillance systems for emerging infectious diseases.

Using internet search queries for infectious disease surveillance: screening diseases for suitability.

BACKGROUND: Internet-based surveillance systems provide a novel approach to monitoring infectious diseases. Surveillance systems built on internet data are economically, logistically and epidemiologically appealing and have shown significant promise. The potential for these systems has increased with increased internet availability and shifts in health-related information seeking behaviour. This approach to monitoring infectious diseases has, however, only been applied to single or small groups of select diseases. This study aims to systematically investigate the potential for developing surveillance and early warning systems using internet search data, for a wide range of infectious diseases. METHODS: Official notifications for 64 infectious diseases in Australia were downloaded and correlated with frequencies for 164 internet search terms for the period 2009-13 using Spearman's rank correlations. Time series cross correlations were performed to assess the potential for search terms to be used in construction of early warning systems. RESULTS: Notifications for 17 infectious diseases (26.6%) were found to be significantly correlated with a selected search term. The use of internet metrics as a means of surveillance has not previously been described for 12 (70.6%) of these diseases. The majority of diseases identified were vaccine-preventable, vector-borne or sexually transmissible; cross correlations, however, indicated that vector-borne and vaccine preventable diseases are best suited for development of early warning systems. CONCLUSIONS: The findings of this study suggest that internet-based surveillance systems have broader applicability to monitoring infectious diseases than has previously been recognised. Furthermore, internet-based surveillance systems have a potential role in forecasting emerging infectious disease events, especially for vaccine-preventable and vector-borne diseases.

Microbial events in the hindgut during carbohydrate-induced equine laminitis.

Equine laminitis is the most serious foot disease of the horse, often resulting in death or euthanasia. Laminitis has long been recognized as an affliction of horses, as has the association of this condition with the ingestion of carbohydrates. Research into the pathophysiology of this condition has been facilitated by the development of reliable models for experimentally inducing laminitis, and DNA-based techniques for profiling complex microbiomes have dramatically increased the knowledge of the microbiology of this disease. Recent studies have provided substantial evidence showing equine hindgut streptococcal species to be the most likely causative agent. Although these studies are not definitive, they provide the foundations for future work to determine the source of laminitis trigger factors and their mechanisms of action.

Microbial ecology of the equine hindgut during oligofructose-induced laminitis.

Alimentary carbohydrate overload is a significant cause of laminitis in horses and is correlated with drastic shifts in the composition of hindgut microbiota. Equine hindgut streptococcal species (EHSS), predominantly Streptococcus lutetiensis, have been shown to be the most common microorganisms culturable from the equine caecum prior to the onset of laminitis. However, the inherent biases of culture-based methods are estimated to preclude up to 70% of the normal caecal microbiota. The objective of this study was to evaluate bacterial population shifts occurring in the equine caecum throughout the course of oligofructose-induced laminitis using several culture-independent techniques and to correlate these with caecal lactate, volatile fatty acid and degrees of polymerization 3-7 fructo-oligosaccharide concentrations. Our data conclusively show that of the total microbiota present in the equine hindgut, the EHSS S. lutetiensis is the predominant microorganism that proliferates prior to the onset of laminitis, utilizing oligofructose to produce large quantities of lactate. Population shifts in lactobacilli and Escherichia coli subpopulations occur secondarily to the EHSS population shifts, thus confirming that lactobacilli and coliforms have no role in laminitis. A large, curved, Gram-negative rod previously observed during the early phases of laminitis induction was most closely related to the Anaerovibrio genus and most likely represents a new, yet to be cultured, genus and species. Correlation of fluorescence in situ hybridization and quantitative real-time PCR results provide evidence supporting the hypothesis that laminitis is associated with the death en masse and rapid cell lysis of EHSS. If EHSS are lysed, liberated cellular components may initiate laminitis.

Phylogenetic analysis of Porphyromonas species isolated from the oral cavity of Australian marsupials.

Porphyromonas species are frequently isolated from the oral cavity and are associated with periodontal disease in both animals and humans. Black, pigmented Porphyromonas spp. isolated from the gingival margins of selected wild and captive Australian marsupials with varying degrees of periodontal disease (brushtail possums, koalas and macropods) were compared phylogenetically to Porphyromonas strains from non-marsupials (bear, wolf, coyote, cats and dogs) and Porphyromonas gingivalis strains from humans using 16S rRNA gene sequence analysis. The results of the phylogenetic analysis identified three distinct groups of strains. A monophyletic P. gingivalis group (Group 1) contained only strains isolated from humans and a Porphyromonas gulae group (Group 2) was divided into three distinct subclades, each containing both marsupial and non-marsupial strains. Group 3, which contained only marsupial strains, including all six strains isolated from captive koalas, was genetically distinct from P. gulae and may constitute a new Porphyromonas species.

Streptococcus henryi sp. nov. and Streptococcus caballi sp. nov., isolated from the hindgut of horses with oligofructose-induced laminitis.

Four Gram-positive, catalase-negative, coccoid-shaped isolates were obtained from the caecum and rectum of horses with oligofructose-induced equine laminitis. Phenotypic and phylogenetic studies were performed on these isolates. Initial biochemical profiling assigned two of the isolates to Streptococcus bovis. The other two isolates, however, could not be assigned conclusively on the basis of their biochemical profiles. Gene sequence analysis demonstrated that the four new isolates were related most closely to Streptococcus suis based on the 16S rRNA gene and to Streptococcus orisratti based on the manganese-dependent superoxide dismutase gene (sodA). Sequence divergence values from recognized Streptococcus species based on these two genes were >3 and >13%, respectively, for all four isolates. Phylogenetic and phenotypic analyses demonstrated that the four isolates formed two distinct clonal groups that are suggested to represent two novel species of the genus Streptococcus. The names proposed for these organisms are Streptococcus henryi sp. nov. (type strain 126(T) =ATCC BAA-1484(T) =DSM 19005(T)) and Streptococcus caballi sp. nov. (type strain 151(T) =ATCC BAA-1485(T) =DSM 19004(T)).

Fluorescence in situ hybridization analysis of hindgut bacteria associated with the development of equine laminitis.

Carbohydrate-induced laminitis in horses is characterized by marked changes in the composition of the hindgut microbiota, from a predominantly Gram-negative population to one dominated by Gram-positive bacteria. The objective of this study was to monitor changes in the relative abundance of selected hindgut bacteria that have previously been implicated in the pathophysiology of equine laminitis using fluorescence in situ hybridization (FISH). Caecal cannulae were surgically implanted in five Standardbred horses and laminitis induced by oral administration of a bolus dose of oligofructose. Caecal fluid and faecal specimens were collected over a 48 h period at 2 to 4 h intervals post-oligofructose administration and subjected to FISH using probes specific for nine bacterial groups to determine changes in their relative abundance compared with total bacteria hybridizing to the generic EUBMIX probe. Additionally, hoof biopsies were taken over the course of the experiment at 6 h intervals and evaluated for histopathological changes consistent with laminitis, allowing changes in hindgut microbiota to be correlated with the onset of lesions in the foot. Of the microorganisms specifically targeted, streptococci of the Streptococcus bovis/equinus complex were the only bacteria that consistently proliferated in both caecal fluid and faeces immediately before the onset of histological signs of laminitis. Furthermore, lactobacilli, Enterobacteriaceae, Allisonella histaminiformans, enterococci, Bacteroides fragilis, Mitsuokella jalaludinii and Clostridium difficile did not establish significant populations in the hindgut before the onset of equine laminitis.