The effectiveness of antibiotics for treating gonococcal infections is compromised due to escalating antibiotic resistance; and the development of an effective gonococcal vaccine has been challenging. Emerging evidence suggests that the licensed meningococcal B (MenB) vaccine, 4CMenB is effective against gonococcal infections due to cross-reacting antibodies and 95% genetic homology between the two bacteria, and that cause the diseases. This project aims to undertake epidemiological and genomic surveillance to evaluate the long-term protection of the 4CMenB vaccine against gonococcal infections in the Northern Territory (NT) and South Australia (SA), and to determine the potential benefit of a booster vaccine doses to provide longer-term protection against gonococcal infections.This observational study will provide long-term evaluation results of the effectiveness of the 4CMenB vaccine against gonococcal infections at 4-7 years post 4CMenB programme implementation. Routine notifiable disease notifications will be the basis for assessing the impact of the vaccine on gonococcal infections. Pathology laboratories will provide data on the number and percentage of positive tests relative to all tests administered and will coordinate molecular sequencing for isolates. Genome sequencing results will be provided by SA Pathology and Territory Pathology/New South Wales Health Pathology, and linked with notification data by SA Health and NT Health. There are limitations in observational studies including the potential for confounding. Confounders will be analysed separately for each outcome/comparison.The protocol and all study documents have been reviewed and approved by the SA Department for Health and Well-being Human Research Ethics Committee (HREC/2022/HRE00308), and the evaluation will commence in the NT on receipt of approval from the NT Health and Menzies School of Health Research Human Research Ethics Committee. Results will be published in peer-reviewed journals and presented at scientific meetings and public forums.

In Australia, invasive meningococcal disease (IMD) incidence rapidly increased between 2014 and 2017 due to rising serogroup W (MenW) and MenY infections. We aimed to better understand the genetic diversity of IMD during 2017 and 2018 using whole genome sequencing data.Whole genome sequencing data from 440 Australian IMD isolates collected during 2017 and 2018 and 1737 international MenW:CC11 isolates collected in Europe, Africa, Asia, North America, and South America between 1974 and 2020 were used in phylogenetic analyses; genetic relatedness was determined from single-nucleotide polymorphisms.Australian isolates were as follows: 181 MenW (41%), 144 MenB (33%), 88 MenY (20%), 16 MenC (4%), 1 MenW/Y (0.2%), and 10 nongenogroupable (2%). Eighteen clonal complexes (CCs) were identified, and 3 (CC11, CC23, CC41/44) accounted for 78% of isolates (343/440). These CCs were associated with specific serogroups: CC11 (n = 199) predominated among MenW (n = 181) and MenC (n = 15), CC23 (n = 80) among MenY (n = 78), and CC41/44 (n = 64) among MenB (n = 64). MenB isolates were highly diverse, MenY were intermediately diverse, and MenW and MenC isolates demonstrated the least genetic diversity. Thirty serogroup and CC-specific genomic clusters were identified. International CC11 comparison revealed diversification of MenW in Australia.Whole genome sequencing comprehensively characterized Australian IMD isolates, indexed their genetic variability, provided increased within-CC resolution, and elucidated the evolution of CC11 in Australia.

We describe the recent temporal patterns of respiratory syncytial virus (RSV) and influenza virus detections in the Northern Territory (NT) of Australia, between 2020 and 2023.This retrospective analysis of patients presenting with respiratory diseases utilised a multiplex viral nucleic acid detection assay for RSV, influenza and SARS Cov2 (COVID-19) to determine the relative frequency of non-COVID-19 respiratory viral detections by age and month during the study period.During this period of the NT COVID-19 epidemic, disruption of the usual annual wet season RSV outbreak patterns occurred, and the yearly influenza peak was absent for two annual cycles. Our data also reveals that 25% of RSV infections were occurring in patients greater than 40 years of age, compared to 32% of influenza infections presenting in the same period, documenting a greater burden of adult disease than previously documented in the NT.Loss of non-COVID-19 viral seasonality and a substantial unrecognised RSV adult burden were noted. We will continue to monitor seasonality, and the RSV burden and this will help to target the populations benefiting from recently released RSV vaccine.

Melioidosis caused by Burkholderia pseudomallei causes significant morbidity and mortality in Southeast Asia and northern Australia. Clinical manifestations remain diverse, including localized skin infection, pneumonia, and chronic abscess formation. Culture remains the gold standard of diagnosis, with serology and antigen detection tests playing a role if culture is unfeasible. Serologic diagnosis remains challenging, with limited standardization across different assays. In areas of endemicity, high rates of seropositivity have been documented. The indirect hemagglutination assay (IHA) is one of the more widely used serologic tests in these areas. In Australia, only three centers perform the test. Annually, laboratory A, laboratory B, and laboratory C perform approximately 1,000, 4,500, and 500 tests, respectively. A comparison of a total of 132 sera was analyzed from the routine quality exchange program between these centers from 2010 until 2019. Overall, 18.9% of sera tested had an interpretative discrepancy between laboratories. IMPORTANCE This study found significant discrepant results between three Australian centers offering the melioidosis indirect hemagglutination assay (IHA), despite testing the same samples. We have highlighted that the IHA is a nonstandardized test, which had different source antigens at each of the different laboratories. Melioidosis is a global disease, is associated with significant mortality, and is perhaps under recognized. It is likely to have increasing impact with changing weather patterns. The IHA has been used frequently as an adjunct to the diagnosis of clinical disease and is the mainstay of determining seroprevalence within populations. Despite its relative ease of use, especially in low resource settings, our study highlights the significant limitations of the melioidosis IHA. It has wide ranging implications, serving as an impetus for developing better diagnostic tests. This study is of interest to practitioners and researchers working in the various geographic regions affected by melioidosis.

Bartonella henselae is a zoonotic Gram-negative Bacillus associated with self-limited regional lymphadenopathy. In recent decades, an expanding spectrum of clinical manifestations has been described, in part, due to improved diagnostics. However, updated epidemiological data are sparse. We retrospectively reviewed the clinical features of 31 patients with B. henselae infection older than 15 years from 2005 to 2019, in the tropical Top End of Australia. Our annual disease incidence of 1.3 cases per 100,000 population is lower than that in the national database surveillances in the United States, but the hospitalization incidence of 0.9 per 100,000 population in our region is higher than those reported in the literature, with an average length of stay of 9 days. Patients were more commonly male, aboriginal, and aged less than 14 years (median age: 7 years), living in a rural setting with presentation during our monsoon season. The disease spectrum included lymph node disease (74%), organ peliosis, endocarditis, cutaneous lesions, parapharyngeal abscess, parotitis, and neurologic and ocular syndromes. Lymph node disease was far commoner in children than the more serious systemic B. henselae infections associated with adults (P = 0.074). Although no deaths were reported, significant morbidities were observed. Two endocarditis cases presented with glomerulonephritis, and hematological and neurological features mimicking vasculitis, and consequently received immunosuppressants. One case was only diagnosed after representation with serial embolic strokes. Given the heterogeneity of disease manifestations with nonspecific symptoms and significant consequences, a timely and accurate diagnosis is needed to avoid unnecessary treatments or interventions.

The objective of this study was to develop a real-time PCR assay targeting the gonococcal porB gene (PorB-PCR) for predicting susceptibility of Neisseria gonorrhoeae to penicillin. This complements a previously described PCR assay for detecting penicillinase-producing N. gonorrhoeae (PPNG) developed by our laboratory (PPNG-PCR). The PorB-PCR assay was designed using six probes to characterize various combinations of amino acids at positions 101 and 102 of the PorB1b class protein, including the WT G101/A102 and mutant G101K/A102D, G101K/A102N and G101K/A102G sequences, as well as the PorB1a sequence. The ability of these sequences to predict penicillin susceptibility was initially assessed using 2307 N. gonorrhoeae isolates from throughout Australia for which phenotypic susceptibility data were available. The assay was then applied to N. gonorrhoeae-positive clinical specimens (n = 70). Specificity was assessed by testing commensal Neisseria strains (n = 75) and N. gonorrhoeae-negative clinical specimens (n = 171). Testing of the 2307 N. gonorrhoeae isolates using PorB-PCR to detect G101/A102 and PorB1a sequences identified a total of 78.4% (61.2% and 17.2%, respectively) of penicillin-susceptible isolates with specificities of 97.4% and 99.3% and positive predictive values of 98.8% and 98.9%, where PPNG strains were simultaneously identified and excluded. Similar performance data were obtained when the PorB-PCR assay was applied to the N. gonorrhoeae-positive clinical specimens. No false-positive results were observed for the N. gonorrhoeae-negative samples and no cross-reactions were observed with the non-gonococcal species. When used in parallel with the previously described PPNG-PCR, the PorB-PCR approach has the potential to facilitate individualized treatment of gonorrhoea using penicillin.

Neisseria gonorrhoeae antimicrobial resistance (AMR) is a globally recognized health threat; new strategies are needed to enhance AMR surveillance. The Northern Territory of Australia is unique in that 2 different first-line therapies, based primarily on geographic location, are used for gonorrhea treatment. We tested 1,629 N. gonorrhoeae nucleic acid amplification test-positive clinical samples, collected from regions where ceftriaxone plus azithromycin or amoxicillin plus azithromycin are recommended first-line treatments, by using 8 N. gonorrhoeae AMR PCR assays. We compared results with those from routine culture-based surveillance data. PCR data confirmed an absence of ceftriaxone resistance and a low level of azithromycin resistance (0.2%), and that penicillin resistance was <5% in amoxicillin plus azithromycin regions. Rates of ciprofloxacin resistance and penicillinase-producing N. gonorrhoeae were lower when molecular methods were used. Molecular methods to detect N. gonorrhoeae AMR can increase the evidence base for treatment guidelines, particularly in settings where culture-based surveillance is limited.

BACKGROUND: The demographic of Northern Territory prison population differs than elsewhere in Australia and the prevalence of hepatitis B and hepatitis C may therefore be somewhat different from other jurisdictions. There has been no study which has specifically described the serological results of a large proportion of prisoners in Northern Territory correctional facilities over an extended period of time. METHODS: This retrospective longitudinal study reviewed serological results and testing rates for hepatitis B, and hepatitis C performed in correctional facilities in the Northern Territory of Australia between July 1st, 2003 and June 30th, 2017. RESULTS: The proportion of positive records over 14 years for hepatitis B surface antigen (HBsAg) was 641/12,066 (5.3, 95% CI 4.9-5.7), for hepatitis B core antibody (anti-HBc) 4937/12,138 (40.1, 95%CI 39.8-41.6), for hepatitis B surface antibody (anti-HBs) 6966/13,303 (52.4, 95% CI 51.5-53.2), and for hepatitis C antibody 569/12,153 (4.7, 95% CI 4.3-5.1). The proportion of prisoners tested for hepatitis B and hepatitis C has decreased since 2015, while a high proportion of prisoners remain non-immune to hepatitis B. CONCLUSION: There is a relatively high proportion of positive serological markers of hepatitis B, and a lower proportion of positive hepatitis C serology in the Northern Territory's correctional facilities compared to overall Australian rates. As the proportion of prisoners tested for hepatitis B and C has decreased recently, and a high proportion of prisoners remain non-immune to hepatitis B, there are opportunities to increase testing and vaccination rates in this population.

Immunochromatographic test (ICT) kits for the rapid detection of immunoglobulin G (IgG) and IgM antibodies to Burkholderia pseudomallei were compared to the indirect hemagglutination (IHA) assay. In 138 culture-confirmed melioidosis cases, sensitivities were 80, 77, and 88% for IHA, ICT IgG, and ICT IgM, respectively. In a prospective study of 160 consecutive sera samples sent for melioidosis serology, respective specificities were 91, 90, and 69, positive predictive values were 41, 32, and 18, and negative predictive values were 99, 98, and 100%. ICT IgM kits are unreliable for diagnosis of melioidosis, but ICT IgG kits may be useful for diagnosing travelers presenting with possible melioidosis who return from regions where melioidosis is endemic.