The emergence of Leptospira borgpetersenii serovar Arborea in Queensland, Australia, 2001 to 2013

BACKGROUND: Leptospirosis is an emerging infectious disease, with increasing frequency and severity of outbreaks, changing epidemiology of populations at risk, and the emergence of new serovars. Environmental drivers of disease transmission include flooding, urbanisation, poor sanitation, changes in land use and agricultural practices, and socioeconomic factors. In Queensland, human infection with Leptosira borgpetersenii serovar Arborea was first reported in 2001. This study aims to report the emergence of serovar Arborea in Queensland from 2001 to 2013, and investigate potential risk factors for infection and drivers of emergence. METHODS: Data on laboratory-confirmed cases of human leptospirosis in Queensland were obtained from the enhanced surveillance system at the WHO/FAO/OIE Collaborating Centre for Reference and Research on Leptospirosis in Brisbane, Australia. The changing epidemiology of serovar Arborea from 2001 to 2003 was described with respect to case numbers, proportion of leptospirosis cases attributed to the serovar, and geographic distribution. Differences in risk factors for the most common serovars were compared. RESULTS: During this period, 1289 cases of leptospirosis were reported, including 233 cases attributed to serovar Arborea. Risk factors for infection include male gender (91 % of cases), occupation, and recreational exposure. Most common occupations recorded were banana workers (28.4 %), meat workers (7.2 %), dairy farmers (5.8 %), graziers/stockmen (5.5 %), 'other agricultural/rural workers' (16.4 %), and tourists or tourism operators (4.6 %). Time trend analysis showed that while non-Arborea cases decreased over the study period, Arborea cases increased by 3.4 cases per year. The proportion of annual cases attributed to Arborea peaked at 49 % in 2011 after unprecedented flooding in Queensland. Mapping of cases by residential location showed expansion of the geographic range of serovar Arborea, concentrating mostly around Brisbane, Cairns and Innisfail. Serovars varied significantly between ages and occupational groups, and serovar Arborea was most strongly associated with 'other agricultural/rural workers'. CONCLUSIONS: Leptospira borgpetersenii serovar Arborea has been emerging in Queensland since 2001, with increase in case numbers, the proportion of leptospirosis infections attributed to the serovar, as well as expansion of its geographic distribution. Reasons for this emergence are unknown, but climatic factors and environmental change are likely to have played important roles

Quantification of microaerobic growth of Geobacter sulfurreducens

Geobacter sulfurreducens was originally considered a strict anaerobe. However, this bacterium was later shown to not only tolerate exposure to oxygen but also to use it as terminal electron acceptor. Research performed has so far only revealed the general ability of G. sulfurreducens to reduce oxygen, but the oxygen uptake rate has not been quantified yet, nor has evidence been provided as to how the bacterium achieves oxygen reduction. Therefore, microaerobic growth of G. sulfurreducens was investigated here with better defined operating conditions as previously performed and a transcriptome analysis was performed to elucidate possible metabolic mechanisms important for oxygen reduction in G. sulfurreducens. The investigations revealed that cell growth with oxygen is possible to the same extent as with fumarate if the maximum specific oxygen uptake rate (sOUR) of 95 mgO2 gCDW-1 h-1 is not surpassed. Hereby, the entire amount of introduced oxygen is reduced. When oxygen concentrations are too high, cell growth is completely inhibited and there is no partial oxygen consumption. Transcriptome analysis suggests a menaquinol oxidase to be the enzyme responsible for oxygen reduction. Transcriptome analysis has further revealed three different survival strategies, depending on the oxygen concentration present. When prompted with small amounts of oxygen, G. sulfurreducens will try to escape the microaerobic area; if oxygen concentrations are higher, cells will focus on rapid and complete oxygen reduction coupled to cell growth; and ultimately cells will form protective layers if a complete reduction becomes impossible. The results presented here have important implications for understanding how G. sulfurreducens survives exposure to oxygen

Development of a Multiple-Locus Variable number of tandem repeat Analysis (MLVA) for Leptospira interrogans and its application to Leptospira interrogans serovar Australis isolates from Far North Queensland, Australia

BACKGROUND: Leptospirosis is a zoonotic disease caused by the genus, Leptospira. Leptospira interrogans is the most common genomospecies implicated in the disease. Epidemiological investigations are needed to distinguish outbreak situations or to trace reservoirs of the organisms. Current methodologies used for typing Leptospira have significant drawbacks. The development of an easy to perform yet high resolution method is needed for this organism. METHODS: In this study we have searched the available genomic sequence of L. interrogans serovar Copenhageni strain Fiocruz L1-130 for the presence of tandem repeats [1]. These repeats were evaluated against reference strains for diversity. Six loci were selected to create a Multiple Locus Variable Number of Tandem Repeats (VNTR) Analysis (MLVA) to explore the genetic diversity within L. interrogans serovar Australis clinical isolates from Far North Queensland. RESULTS: The 39 reference strains used for the development of the method displayed 39 distinct patterns. Diversity Indexes for the loci varied between 0.80 and 0.93 and the number of repeat units at each locus varied between less than one to 52 repeats. When the MLVA was applied to serovar Australis isolates three large clusters were distinguishable, each comprising various hosts including Rattus species, human and canines. CONCLUSION: The MLVA described in this report, was easy to perform, analyse and was reproducible. The loci selected had high diversity allowing discrimination between serovars and also between strains within a serovar. This method provides a starting point on which improvements to the method and comparisons to other techniques can be made

Identification of pathogenic Leptospira species by conventional or real-time PCR and sequencing of the DNA gyrase subunit B encoding gene

BACKGROUND: Leptospira is the causative genus of the disease, leptospirosis. Species identification of pathogenic Leptospira in the past was generally performed by either DNA-DNA hybridisation or 16s rRNA gene sequencing. Both methods have inherent disadvantages such as the need for radio-labelled isotopes or significant homology between species. A conventional and real-time PCR amplification and sequencing method was developed for an alternate gene target: DNA gyrase subunit B (gyrB). Phylogenetic comparisons were undertaken between pathogenic Leptospira 16srRNA and gyrB genes using clustering and minimum evolution analysis. In addition 50 unidentified Leptospira isolates were characterised by gyrB sequencing and compared with conventional 16s rRNA sequencing. RESULTS: A conventional and real-time PCR methodology was developed and optimised for the amplification of the gyrB from pathogenic Leptospira species. Non pathogenic and opportunistic Leptospira species such as L. fainei and L. broomi were not amplified. The gyrB gene shows greater nucleotide divergence (3.5% to 16.1%) than the 16s rRNA gene (0.1% to 1.4%). Minimum evolution analysis reveals that the gyrB has a different evolution topology for L. kirschneri and L. interrogans. When the two genes were compared for the identification of the 50 unknown isolates there was 100% agreement in the results. CONCLUSION: This research has successfully developed a methodology for the identification of pathogenic Leptospira using an alternate gene to 16s rRNA. The gyrB encoding gene shows higher nucleotide/evolutionary divergence allowing for superior identification and also the potential for the development of DNA probe based identification

Review of leptospirosis notifications in Queensland and Australia: January 1998 - June 1999

The World Health Organization/Food and Agricultural Organization Collaborating Centre for Reference and Research on Leptospirosis, Western Pacific Region, accredited since 1958, is part of Queensland Health Scientific Services, which provide tertiary level support in epidemiology, surveillance, training and diagnosis for hospitals and pathology laboratories across the State. Databases for leptospirosis on a global, Australian and State-wide basis are maintained on site and support public health authorities in Australia, WHO and the International Leptospirosis Society. Queensland data collated and analysed from leptospirosis questionnaires, and a brief overview of Australian data based on questionnaire responses for notified cases from 1998 to June 1999, are summarised. The increase in leptospirosis notifications (77%) during 1998 possibly signalled greater awareness of the disease by clinicians. There was a significant increase in leptospirosis notifications for children and students and a high rate of hospitalisation of cases. An outbreak in North Queensland during the first half of 1999 resulted in 184 notifications with over 50% of cases hospitalised. Polymorphic presentation of the disease with severe pulmonary haemorrhage is associated in particular with the serovar australis. Serovar zanoni continues to be a major cause of severe clinical leptospirosis. Several cases were diagnosed in tourists. One of these cases presented with severe respiratory distress and required 14 days in hospital

Long-Term Behavior of Defined Mixed Cultures of Geobacter sulfurreducens and Shewanella oneidensis in Bioelectrochemical Systems

This work aims to investigate the long-term behavior of interactions of electrochemically active bacteria in bioelectrochemical systems. The electrochemical performance and biofilm characteristics of pure cultures of Geobacter sulfurreducens and Shewanella oneidensis are being compared to a defined mixed culture of both organisms. While S. oneidensis pure cultures did not form cohesive and stable biofilms on graphite anodes and only yielded 0.034 ± 0.011 mA/cm2 as maximum current density by feeding of each 5 mM lactate and acetate, G. sulfurreducens pure cultures formed 69 μm thick, area-wide biofilms with 10 mM acetate as initial substrate concentration and yielded a current of 0.39 ± 0.09 mA/cm2. Compared to the latter, a defined mixed culture of both species was able to yield 38% higher maximum current densities of 0.54 ± 0.07 mA/cm2 with each 5 mM lactate and acetate. This increase in current density was associated with a likewise increased thickness of the anodic biofilm to approximately 93 μm. It was further investigated whether a sessile incorporation of S. oneidensis into the mixed culture biofilm, which has been reported previously for short-term experiments, is long-term stable. The results demonstrate that S. oneidensis was not stably incorporated into the biofilm; rather, the planktonic presence of S. oneidensis has a positive effect on the biofilm growth of G. sulfurreducens and thus on current production

Il nome e il sangue secondo Quinto Smirneo. Riprese e trasformazioni di un motivo del duello eroico

The aim of this essay is to examine the rules of duelling in Greek epic poetry from Homer and Arctinus to Quintus Smyrnaeus, within the perspective of composition by theme, which make it possible to identify heroes' ancestry as a specific motif of the epic duel

Antibodies to Leptospira among blood donors in higher-risk areas of Australia: Possible implications for transfusion safety

BACKGROUND: Leptospirosis is one of the most common bacterial zoonoses worldwide, and clinical manifestations range from asymptomatic infection to acute febrile illness, multi-organ failure and death. Asymptomatic, acute bacteraemia in a blood donor provides a potential for transfusion-transmission, although only a single such case from India has been recorded. Human leptospirosis is uncommon in developed countries; however, the state of Queensland in Australia has one of the highest rates among developed countries, especially after increased rainfall. This study examined the prevalence of antibodies to Leptospira spp. in blood donors residing in higher-risk areas of Australia, to evaluate the appropriateness of current blood safety guidelines. MATERIALS AND METHODS: Plasma samples collected from blood donors residing in higher-risk areas of Australia during 2009 and 2011 were included in the study. All samples were tested for the presence of antibodies to 22 leptospiral serovars using the microscopic agglutination test. RESULT: No sample had antibody titres suggestive of a current or recent infection, however, seven samples (1.44%, 95% CI: 0.38-2.50%) had titres suggestive of a past infection. DISCUSSION: This study provides data that may support the appropriateness of current relevant donor selection policies in Australia. Given that the risk profile for leptospirosis is expanding and that the infection is likely to become more prevalent with climate change, this disease may become more of a concern for transfusion safety in the futur

The role of pre-sleep cognitions in adolescent sleep-onset problems

© 2018 Elsevier BV. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 12 month embargo from date of publication (March 2018) in accordance with the publisher’s archiving policy.Study Objectives: To examine the relationship between pre-sleep cognitions and sleep-onset difficulties in an adolescent sample. Methods: Participants were 385 students (59% male) from grades 9 to 11, between 13 and 18 yrs old (M=15.6, SD=1.0), from 8 co-educational high schools of varied socioeconomic status in metropolitan Adelaide, South Australia. The cross-sectional study used a questionnaire battery including the Sleep Anticipatory Anxiety Questionnaire - Adolescent Version [SAAQ-A], completed during school time, followed by 8 days of sleep diary completion and wearing wrist actigraphy to obtain subjective and objective sleep onset latency [SOL]. Results: Significant relationships were found between somatic arousal (SAAQ-A subscale) and objective SOL, and between sleep-related cognitions (SAAQ-A subscale) and subjective SOL and SOL overestimation (sleep misperception). No relationships were found between subjective SOL and somatic or rehearsal and planning cognitions. Objective SOL was not related to rehearsal and planning, or sleep-related cognition scores, and sleep misperception had no relationship with somatic, and rehearsal and planning cognition scores. Conclusions: These findings are similar to those in clinical adult populations, but also notably different, for example the lack of association between negative sleep-related pre-sleep cognitions and objective sleep difficulty. This study’s results provide a basis for existing relationships between negative pre-sleep cognitions and subjective and objective sleep difficulties in this population to be examined causally in more detail