Search and Contain: Impact of an Integrated Genomic and Epidemiological Surveillance and Response Program for Control of Carbapenemase-producing Enterobacterales.

BACKGROUND: Multiresistant organisms (MROs) pose a critical threat to public health. Population-based programs for control of MROs such as carbapenemase-producing Enterobacterales (CPE) have emerged and evaluation is needed. We assessed the feasibility and impact of a statewide CPE surveillance and response program deployed across Victoria, Australia (population 6.5 million). METHODS: A prospective multimodal intervention including active screening, carrier isolation, centralized case investigation, and comparative pathogen genomics was implemented. We analyzed trends in CPE incidence and clinical presentation, risk factors, and local transmission over the program's first 3 years (2016-2018). RESULTS: CPE case ascertainment increased over the study period to 1.42 cases/100 000 population, linked to increased screening without a concomitant rise in active clinical infections (0.45-0.60 infections/100 000 population, P = .640). KPC-2 infection decreased from 0.29 infections/100 000 population prior to intervention to 0.03 infections/100 000 population in 2018 (P = .003). Comprehensive case investigation identified instances of overseas community acquisition. Median time between isolate referral and genomic and epidemiological assessment for local transmission was 11 days (IQR, 9-14). Prospective surveillance identified numerous small transmission networks (median, 2; range, 1-19 cases), predominantly IMP and KPC, with median pairwise distance of 8 (IQR, 4-13) single nucleotide polymorphisms; low diversity between clusters of the same sequence type suggested genomic cluster definitions alone are insufficient for targeted response. CONCLUSIONS: We demonstrate the value of centralized CPE control programs to increase case ascertainment, resolve risk factors, and identify local transmission through prospective genomic and epidemiological surveillance; methodologies are transferable to low-prevalence settings and MROs globally.

Recent trends in invasive group A Streptococcus disease in Victoria

Background: Invasive Group A Streptococcus (iGAS) disease can cause permanent disability and death. The incidence of iGAS has increased in many developed countries since the 1980s. iGAS disease is not nationally notifiable in Australia or at the state level in Victoria. The Victorian Hospital Pathogen Surveillance Scheme (VHPSS) is a voluntary laboratory-based surveillance system established in 1988. We assessed the trends and molecular epidemiology of iGAS disease in Victoria from 2007-2017. Methods: A case of iGAS was defined as an individual for whom Group A Streptococcus (GAS) was isolated from a normally sterile body site. Data on all iGAS cases, as reported to the VHPSS, between 1 January 2007 and 31 December 2017 were examined. Results: A total of 1,311 iGAS cases had associated isolates, and M Protein Gene (emm) typing was performed for 91.6%. The mean annual incidence was 2.1 (95% CI: 1.8-2.5) per 100,000 population per year, increasing 2.7-fold over the study period. In total, 140 different iGAS emm-types were observed, with the ten most prevalent types comprising 63.1% of the sample. Conclusions: Despite limitations in this surveillance data, we observed increasing rates of iGAS disease in Victoria. iGAS incidence exceeded the mean annual incidence for invasive meningococcal disease, calculated using Victorian data from the National Notifiable Diseases Surveillance System (2.1 vs. 0.6 cases per 100,000 population per year, respectively). Mandatory case notification could enhance disease control and prevention. Further, the diversity in emm-types emphasises the importance of effective secondary chemoprophylaxis in prevention, alongside GAS vaccine development.