Indigenous populations globally are disproportionately affected by chronic hepatitis B virus (HBV) infection however contemporary sero-prevalence data are often absent. In the Indigenous population of the Northern Territory (NT) of Australia the unique C4 sub-genotype of HBV universally circulates. There are no studies of the sero-prevalence, nor the impact of the vaccination program (which has a serotype mismatch compared to C4), at a population-wide level. We examined all available HBV serology results obtained from the three main laboratories serving NT residents between 1991 and 2011. Data were linked with a NT government database to determine Indigenous status and the most recent test results for each individual were extracted as a cross-sectional database including 88,112 unique individuals. The primary aim was to obtain a contemporary estimate of HBsAg positivity for the NT by Indigenous status. Based on all tests from 2007-2011 (35,633 individuals), hepatitis B surface antigen (HBsAg) positivity was 3·40% (95%CI 3·19-3·61), being higher in Indigenous (6·08%[5·65%-6·53%]) than non-Indigenous (1·56%[1·38%-1·76%]) Australians, p<0·0001. Birth cohort analysis showed HBsAg positivity fell over time for Indigenous people, with this decrease commencing prior to universal infant vaccination (which commenced in 1990), with an ongoing but slower rate of decline since 1990, (0·23% decrease per year versus 0·17%). HBsAg positivity is high in the NT, particularly in the Indigenous population. HBsAg positivity has fallen over time but a substantial part of this decrease is due to factors other than the universal vaccination program.

In tropical northern Australia, approximately 20% of Staphylococcus aureus bacteremia is caused by methicillin-resistant Staphylococcus aureus (MRSA). We prospectively evaluated the impact on clinician antibiotic prescribing of the results obtained from performing the GeneXpert MRSA/SA test on 151 positive blood cultures with clustered gram-positive cocci. The GeneXpert result led to earlier appropriate prescription of vancomycin for 54% of patients with MRSA; 25% of patients avoided vancomycin, and 16% of patients had all antibiotics ceased.

BACKGROUND AND AIM: The hepatitis B surface antigen was first described in the blood of an Indigenous Australian man, yet little is known about its molecular epidemiology in this population, in which it is endemic. The study aimed to determine the clinical and molecular epidemiology of hepatitis B virus (HBV) in Indigenous people from northern Australia. METHODS: Following ethics approval and informed consent, blood specimens and clinical details from Indigenous adults known to be infected with HBV and who were born and raised in Indigenous communities in northern Australia were obtained. HBV genotypes were determined in isolates with sufficient HBV DNA by polymerase chain reaction by sequencing of the polymerase/surface gene. RESULTS: Between June 2010 and June 2012, 65 patients were recruited from six different regions of northern Australia. Thirty-two patients (49%) were hepatitis B e-antigen-positive, and 48% were hepatitis B e-antibody-positive. No patients were found to be coinfected with hepatitis C virus or human immunodeficiency virus. Of the 49 samples with sufficient viral load for genotyping, 100% were infected with genotype C4, previously only reported from two Indigenous Australians. All isolates had wild-type polymerase gene sequences despite 14 currently or previously receiving antiviral treatment. The canonical sG145R vaccine-escape variant was detected in the surface antigen of virus from two patients. CONCLUSIONS: The exclusive HBV genotype in this ancient population is genotype C4. Whole genome sequencing and clinical follow-up of this cohort are in progress, with the aim of exploring the clinical significance of these findings.

In Australia's Northern Territory, the hepatitis B virus (HBV) subgenotype A2 (subtype adw2) vaccine was introduced in 1988 for Indigenous infants. Subsequently, the circulating viral genotype has been identified as subgenotype C4 (subtype ayw3). We assessed HBV vaccine effectiveness (VE) in light of this subtype mismatch. Participants of the Aboriginal Birth Cohort (ABC) study were recruited at birth (1987-1990), with HBV serology obtained at follow-up waves 3 (2005-2007) and 4 (2013-2015). Participants were immune if HBV surface antibody levels exceeded 10 IU/L. We determined the VE against any HBV infection (anti-HBc+) and against chronic infection (HBsAg+ or HBV DNA+), comparing non-vaccinated participants with those fulfilling United States Centers for Disease Control and Prevention (CDC) criteria for full HBV immunisation. Of 686 participants in the ABC study, we obtained HBV serology from 388 at wave 4. 181 participants were immune to HBV and 97 had evidence of any infection. Seven participants were chronically infected, of whom five had received three vaccine doses, and anti-HBc seroconversion had occurred subsequent to the three vaccine doses for two of these seven participants. Comparing the 107 participants who had been vaccinated in accordance with CDC recommendations and 127 who had not been vaccinated, VE against any infection was 67% (95%CI, 43-104%). The odds of being anti-HBc+ was 87% lower in participants raised in urban settings compared to those born into families from remote areas (OR, 0.1; 95%CI, 0.03-0.4). In a setting where there exists a subtype mismatch between vaccine and circulating genotype, the vaccine was largely effective in preventing chronic infection but sub-optimal against any infection. The implications of a high prevalence of anti-HBc seropositivity in this population are unclear and require further study. The fact that anti-HBc seropositivity was strongly associated with remote dwelling suggests ongoing viral exposure in remote settings.

To establish the relationship between hepatitis B virus (HBV) and human T-cell lymphotropic virus type 1 (HTLV-1) serological markers in the Northern Territory, Australia. A retrospective serological study of patients presenting to public healthcare facilities in the Northern Territory between 2008 and 2015 was performed in order to determine the presence and relationships of serological markers of HBV and HTLV-1. Seven hundred and forty individual patients were found to be serologically positive for HTLV-1 in the Northern Territory over the 8-year period. Hepatitis B results were available for 521 of these patients. Hepatitis B surface antigen (HBsAg) positivity was demonstrated in 15.9% (83/521) of this cohort, which was significantly different to the HTLV-1-negative group (3.7%, 125/3354) (p<0.001). Excluding individuals with isolated hepatitis B surface antibody (anti-HBs), those in the HTLV-1-positive group had a higher HBV exposure history (67.5%, 352/521) when compared to HTLV-1-negative individuals (37.8%, 1259/3354) (p<0.001). HTLV-1-positive individuals had a lower prevalence of HBV combined anti-HBs and hepatitis B core antibody (anti-HBc) positive markers compared to those who were HTLV-1-negative (56.3% (198/352) versus 73.8% (937/1269), respectively; p<0.001). A significantly higher prevalence rate of HBV was found in HTLV-1-positive individuals from the Northern Territory. When considering the higher exposure to HBV in HTLV-1-positive individuals, the clearance of HBV appears lower than in those individuals testing HTLV-1-negative. A lower prevalence of clearance in HTVL-1-positive individuals than in HTLV-1-negative individuals, as signified by formation of HBVcAb and HBVsAb in HTVL-1 positive individual's may equate to higher prevalence of ongoing coinfection.

  To describe the incidence and prevalence of blood-borne viruses (BBV) including: hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV) and human T-cell leukaemia virus type-1 (HTLV) in the haemodialysis-dependent population of the Top End of the Northern Territory (TENT).   We retrospectively reviewed the serology of BBV in a longitudinal fashion in the haemodialysis-dependent population treated in the TENT of Australia from 2000 to 2009 inclusive. HBV, HCV, HIV and HTLV serology on commencement of dialysis and at exit or January 2010, whichever was earlier, as well as demographic details were collected. Patients with a change in serological status had all serology reviewed.   Four-hundred and forty patients were included in the analysis. Of these, 84.3% were Indigenous and 55.4% female, with a median age of 50 (IQR 43-59) years at the commencement of haemodialysis. Evidence of past HBV infection was documented in 42.7% and 8.9% were hepatitis B surface antigen-positive. Positive serology for HTLV was documented in 2.2%, 1.6% were hepatitis C antibody-positive and no individual was HIV-positive. Three patients had a definite change in their HBV serology over time; this equates to an absolute seroconversion risk of 0.1 per 100 person years or 0.0006 per dialysis episode.   In this cohort, there was a high rate of past and current hepatitis B infection but low rates of seroconversion while on haemodialysis.

Surgical site skin infections (SSIs) are a preventable complication of delivery via caesarean section (c-section). After observing a high rate of SSIs following c-section, we reviewed SSIs following c-section over a 14-month period. In addition, we assessed all women undergoing c-section during the final 6 months of the study period to determine the risk factors for SSIs in our population. During the review period, 6.9%(40 of 583) of women developed a SSI following c-section. The rate of SSIs was five times higher in Indigenous women compared with non-Indigenous women (16.6% v. 3.3%, P = 0.001). Diabetes mellitus, high ASA score and the use of staples to close the wound were also associated with SSIs (6 of 18 v. 24 of 199, P = 0.02; 2 v. 1, P = 0.003; 10 of 18 v. 49 of 199, P = 0.002). Length of stay was increased by 4 days in women who had the SSI diagnosed during their initial admission (P = 0.001), and a quarter of women with a SSI required readmission. Sixty-four percent (18 of 28) of isolates were Staphylococcus aureus, of which 44% were community-associated methicillin-resistant S. aureus (8 of 18). Twenty-nine percent of isolates were not susceptible to cephazolin, the standard antimicrobial prophylaxis used. After changing surgical skin preparation to alcoholic 2% chlorhexidine, adding gentamicin to cephazolin for preincisional antibiotic prophylaxis and educating staff, the rate of SSIs halved to 3.3%. Many of the SSIs that occurred after the new measures were introduced were in women who had not received gentamicin prophylaxis, highlighting the importance of ongoing staff education.

OBJECTIVES: To determine the prevalence and trends of human hookworm infection (HWI) in the Northern Territory over the past 10 years, and to assess the influence of the community children's deworming program (CCDP). DESIGN, PATIENTS AND SETTING: A retrospective observational analysis of consecutive microbiologically confirmed cases of HWI in patients diagnosed at NT government health care facilities and the main private laboratory servicing the NT between January 2002 and July 2012. MAIN OUTCOME MEASURES: Annual prevalence of HWI (2002-2011); age, sex, Indigenous status, residence, haemoglobin level and eosinophil count of patients with HWI; and proportion of patients within the CCDP target population (children aged 6 months to 16 years, who should receive 6-monthly albendazole). RESULTS: From 64 691 faecal samples examined during the study period, hookworm was detected in 112 patients. There was a downward trend in the annual prevalence of HWI, falling from 14.0 cases per 100 000 population (95% CI, 8.8-19.2) in 2002 to 2.2 per 100 000 population (95% CI, 0.3-4.1) in 2011. Only 16 patients (14.3%) fell within the CCDP target population. Seventy-one patients (63.4%) were living in remote communities, and 94 (84.7%) were recorded as Indigenous Australians. CONCLUSIONS: The prevalence of HWI in the NT reduced over the 10-2013 period. HWI predominantly occurs in individuals outside the CCDP target population. Our data support continuation of the CCDP in conjunction with improvements in housing, health hardware and health promotion. Continued use of albendazole in individuals beyond the CCDP may facilitate the eventual eradication of HWI from the NT.