Communicable diseases intelligence (2018)最新文献

In March 2024, the Department of Health in Western Australia investigated an outbreak of Salmonella linked to a food venue serving bánh mì (Vietnamese sandwiches). Outbreak cases were notified via laboratories, health services, local government, and cases referring sick co-exposed individuals. Structured interviews were conducted to determine demographic, illness and food exposure histories, and descriptive analyses were performed. The investigation identified 146 outbreak cases linked to the food venue. All outbreak cases had symptoms of salmonellosis, and 34 cases (24%) were hospitalised. Descriptive analysis found a strong association between illness and the consumption of bánh mì (139 cases) or tofu salad (three cases) from the food venue. This finding was supported by environmental and laboratory evidence, with Salmonella Typhimurium multilocus variable-number tandem repeat analysis linking 112 cases (77%) to samples from the food venue's benchtop blender and tofu mix. The contaminated blender had been used to make three products: chicken and pork liver pâté, raw-egg mayonnaise, and a crispy rice tofu. The liver was undercooked before blending and was suspected to be the most likely source of the outbreak. To control the outbreak, the venue stopped using the blender and switched to using commercial mayonnaise, and staff were trained on safer cooking and hygiene processes. The outbreak highlights the critical importance of application of food safety standards in commercial kitchens, especially in relation to commonly used appliances, and to raw liver and mayonnaise products. Furthermore, it demonstrated that open and timely communication between food businesses, local government, laboratories and health agencies are key to the rapid identification of, and response to, foodborne outbreaks.

This report summarises Australia's spontaneous surveillance data for non-COVID-19 vaccine adverse events following immunisation (AEFI) for 2022, reported to the Therapeutic Goods Administration (TGA). National spontaneous (passive) surveillance data for coronavirus disease 2019 (COVID-19) vaccine AEFI reported to the TGA are analysed and discussed in a separate companion publication. There were 3,642 AEFI reports for non-COVID-19 vaccines administered in 2022, representing an annual AEFI reporting rate of 14.0 per 100,000 population, compared with 13.4 per 100,000 population in 2021. This very small increase in the AEFI reporting rate in 2022 could potentially be related to the combination of several factors: a gradual return to pre-pandemic AEFI reporting patterns; new vaccination programs in response to outbreaks of emergent vaccine preventable diseases (Japanese encephalitis and mpox); and a change in the reporting activities of pharmaceutical sponsors. AEFI reporting rates for individual vaccines in 2022 were similar to 2021.

In 2023, a global increase in invasive group A streptococcal disease (GAS) caused serious illness and death. The North Eastern Public Health Unit (NEPHU) in Victoria, Australia, identified an outbreak of GAS in a school in July 2023; we investigated to describe the epidemiology, to identify risk factors for severe disease, and to implement control measures. We defined confirmed cases as those with laboratory, clinical and epidemiological evidence. Probable cases had clinical evidence with an epidemiological link to a confirmed case but no laboratory evidence. Absentee data were collated for students preceding the onset of the index case. We developed an online, self-administered survey for all students to identify contacts with clinically compatible illnesses. Cultures were genomically sequenced. We identified 11 cases (five confirmed, six probable) among the cohort of 38 (a 29% attack rate), with onset dates from 24 July to 27 August 2023. The index case had a severe invasive GAS infection requiring hospitalisation; eight of 11 cases (73%) reported sore throat and one reported scarlet fever as their primary syndrome. Fifteen of 28 students (54%) were absent from the school during the period preceding the index case's onset. We monitored for two incubation periods following the onset of the last case to 5 September 2023 (six days), with no further cases identified. Isolates all typed as emm1, with genomic clustering consistent with localised transmission. This outbreak demonstrated group A Streptococcus (GAS) transmissibility in a school with multiple clinical manifestations.

From 1 January to 31 December 2024, fifty-five institutions across Australia participated in the Australian Enterococcal Surveillance Outcome Program (AESOP). The aim of AESOP 2024 was to determine the proportion of enterococcal bacteraemia isolates in Australia that were antimicrobial resistant, and to determine the molecular epidemiology of the reported Enterococcus faecium isolates. Of the 1,461 unique episodes of enterococcal bacteraemia investigated, 92.5% were caused by either E. faecalis (51.5%) or E. faecium (41.0%). Ampicillin and vancomycin resistance were not detected in E. faecalis but were detected in 96.8% and 44.5% of E. faecium respectively. Five linezolid-resistant E. faecalis isolates were identified, for which the linezolid minimum inhibitory concentrations (MICs) ranged from 6.0 mg/L to 8.0 mg/L. All five isolates harboured the linezolid resistance optrA gene and were vancomycin susceptible. One linezolid-resistant E. faecium was confirmed with an MIC of 6.0 mg/L. The isolate was vancomycin and teicoplanin resistant and harboured vanA and optrA genes. Overall, 49.8% of E. faecium isolates harboured the vanA and/or the vanB gene: within these isolates, 40.2% harboured vanA, 58.8% harboured vanB, and 1.0% harboured vanA and vanB. The percentage of vancomycin-resistant E. faecium bacteraemia isolates in Australia remains substantially higher than that recorded in most European countries. The E. faecium isolates consisted of 56 multi-locus sequence types (STs); 85.7% of isolates were classified into eight STs, each containing ten or more isolates. The eight STs (ST17, ST78, ST80, ST117, ST555, ST796, ST1421 and ST1424) belonged to clonal complex (CC) 17, a global hospital-adapted polyclonal E. faecium CC, and were found in most Australian jurisdictions. Overall, 54.6% of E. faecium isolates belonging to the eight predominant STs harboured the vanA or vanB gene. AESOP 2024 has shown that enterococcal bacteraemia episodes in Australia continue to be frequently caused by polyclonal ampicillin-resistant high-level gentamicin-resistant vanA- or vanB-positive E. faecium which have limited treatment options.

The Australian Group on Antimicrobial Resistance (AGAR) performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric gram-negative pathogens. From 1 January 2024 to 31 December 2024, fifty-five hospitals across Australia participated in the Australian Gram-negative Surveillance Outcome Program (GnSOP). A total of 10,340 isolates, comprising Enterobacterales (9,376; 90.9%), Pseudomonas aeruginosa (804; 7.7%) and Acinetobacter species (160; 1.4%), were tested using commercial automated methods. The results were analysed using European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2025). Key resistances reported are to the third-generation cephalosporin ceftriaxone in 14.9% of Escherichia coli and 10.5% of Klebsiella pneumoniae complex isolates. Resistance rates to ciprofloxacin were 15.4% for E. coli; 9.7% for the K. pneumoniae complex; 3.8% for the Enterobacter cloacae complex; and 8.8% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 7.5%, 10.3%, 25.2%, and 13.6% for the same four species/complexes, respectively. Thirty-nine Enterobacterales isolates from 38 patients were shown to harbour a carbapenemase gene: 21 with a bla_NDM gene (bla_NDM-5 [8]; bla_NDM-1 [7]; bla_NDM-7 [6]); eight with bla_IMP-4; four with a bla_OXA-181-like gene (bla_OXA-181 [2]; bla_OXA-484 [1]; bla_OXA-1205 [1]); three with a bla_OXA-48-like gene (bla_OXA-48 [2]; bla_OXA-244); two with bla_KPC-2; and one with bla_NDM-5 + bla_OXA-484. Carbapenemase genes were also detected in two P. aeruginosa isolates (bla_NDM-1 [1]; bla_GES-5 [1]).

Increasing antimicrobial resistance and changing epidemiological risk groups for shigellosis pose a threat to Australian public health. Integrated surveillance, enhanced through pathogen genomics data, represents an opportunity to improve the precision of public health responses to drug-resistant shigellosis in Australia and a compelling case study for the new Australian Centre for Disease Control. Here we describe a national public health laboratory scoping study and propose a model for enhanced surveillance of shigellosis that will improve national responses to this emerging public health threat.

Between January 2022 and December 2023, there were 1,827 bloodstream infection (BSI) isolates in 1,745 children and adolescents reported to the Australian Group on Antimicrobial Resistance (AGAR) surveillance outcome programs, with 40% of episodes in children aged < 12 months. Two-thirds of BSIs were community-onset. Of 1,034 gram-negative isolates, 932 (90%) were Enterobacterales. Gram-negative BSI episodes were more commonly community-onset and in children < 12 months of age. Of Enterobacterales isolates, 17.9% were ciprofloxacin resistant; 14.0% were ceftriaxone and/or ceftazidime resistant; 9.5% were gentamicin and/or tobramycin resistant; and 8.9% were piperacillin-tazobactam resistant. Increasing ciprofloxacin resistance was noted, primarily due to the increase in Salmonella Typhi BSI. Overall, 13% of Enterobacterales were extended spectrum β-lactamase producers, and 18.5% were multi-drug resistant (MDR). Of 601 Staphylococcus aureus isolates, 13.6% were methicillin-resistant (MRSA), and 5.5% were MDR. Overall, 14.4% of S. aureus isolates were erythromycin resistant; 10.3% were clindamycin resistant; and 5.0% were ciprofloxacin resistant. Erythromycin, clindamycin, and ciprofloxacin resistance in MRSA were significantly higher than in methicillin-sensitive isolates. No co-trimoxazole resistant S. aureus was isolated. There were 192 enterococcal isolates reported; 70.8% were E. faecalis and 17.2% were E. faecium. All ampicillin-resistant, vancomycin-resistant, and MDR enterococci were E. faecium. The 2022-2023 AGAR Kids Biennial Report shows relative stability in the antimicrobial resistance landscape within the Australian paediatric population, with few significant differences detected when compared to the 2020-2021 report. Small increases in the proportion of resistant Enterobacterales and Enterococcus spp. isolates highlight the importance of ongoing surveillance to inform stewardship and infection prevention interventions.

In Australia, both probable and laboratory-confirmed cases of invasive meningococcal disease (IMD) are reported to the National Notifiable Diseases Surveillance System (NNDSS). When compared to 2023, the number of IMD notifications in 2024 decreased by 5% to 136. IMD was confirmed by laboratory testing in 136/136 (100%) of 2024 IMD cases, with 63% (86/136) diagnosed by bacterial culture and 37% (50/136) by nucleic acid amplification testing. The serogroup was determined for 96% of laboratory-confirmed cases (130/136): serogroup B (MenB) accounted for 84% of infections (109/130); MenY for 14% (18/130); MenW for 1.5% (2/130) and MenC for 0.8% (1/130). Finetyping was available on 71% of the cases for which the serogroup was determined (92/130). In MenB isolates, 21 porA types were detected, the most prevalent of which were P1.7-2,4 (38%; 29/76) and P1.7,16-26 (11%; 8/76). In MenY infections, 6 porA types were detected, with P1.5-1,10-1 the dominant porA type (60%; 9/15); where typed, this was of multilocus sequence type MLST (ST) 1655 and from clonal complex 23 (8/9). One of the two MenW isolates in 2024 was finetyped and identified as porA type P1.5,2, MLST (ST) 11 and belonging to the clonal complex 11, the hypervirulent strain reported in outbreaks in Australia and overseas. The MenC isolate was not typed. Peaks of IMD occurred in children aged less than 5 years, and in those aged 15-24 years, accounting for 20% (27/136) and 28% (38/136) of laboratory-confirmed cases respectively. In children aged under 5 years, 92% (24/26) of IMD was MenB; in those aged 15-24 years, 94% (33/35) of IMD was MenB, with serogroup not determined for one case in those aged < 5 years and three cases aged 15-24 years. IMD was reported in all age groups: < 5 years (20%; 27/136); 5-9 years (6%; 8/136); 10-14 years (5%; 7/136); 15-24 years (28%; 38/136); 25-44 years (12%; 16/136); 45-64 years (18%; 25/136); and in those aged 65 years and older (11%; 15/136). Whilst MenB predominated in all age groups, the majority of MenY IMD cases were reported in adults aged 45 years and older (14/18; 78%). All cultured IMD isolates (n = 86) had antimicrobial susceptibility testing performed with ceftriaxone and penicillin. Minimum inhibitory concentration (MIC) values were reported using Clinical Laboratory Standards Institute (CLSI) interpretative criteria: 7% (6/86) were defined as penicillin resistant (MIC value, ≥ 0.5mg/L); 60% (52/86) had intermediate susceptibility to penicillin (MIC values, 0.125 and 0.25 mg/L); and 33% (28/86) were susceptible to penicillin (MIC values, ≤ 0.064 mg/L). All isolates tested susceptible to ceftriaxone, ciprofloxacin and rifampicin.

From 1 January to 31 December 2024, fifty-five institutions across Australia participated in the Australian Staphylococcus aureus Surveillance Outcome Program (ASSOP). The aim of ASSOP 2024 was to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that were antimicrobial resistant, with particular emphasis on methicillin resistance, and to characterise the molecular epidemiology of methicillin-resistant S. aureus (MRSA). A total of 3,358 SAB episodes were reported, of which 78.5% were community-onset. Overall, 14.9% of S. aureus were methicillin resistant. The 30-day all-cause mortality associated with methicillin-resistant SAB was 13.7%, which was not significantly different to the 14.1% 30-day all-cause mortality associated with methicillin-susceptible SAB (p = 0.9). With the exception of the β-lactams and erythromycin, antimicrobial resistance in methicillin-susceptible S. aureus (MSSA) was infrequent. However, in addition to the β-lactams, 34.8% of MRSA were resistant to erythromycin; 28.9% to ciprofloxacin; 13.1% to gentamicin; 11.0% to tetracycline; and 2.7% to cotrimoxazole. A daptomycin-resistant MRSA from New South Wales was identified. The isolate had a daptomycin minimum inhibitory concentration (MIC) of 6.0 mg/L, and was identified as ST5-V, with a S337L MprF mutation. When applying the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, teicoplanin resistance was detected in three MSSA isolates. Linezolid or vancomycin resistance was not detected. Resistance to the non-β-lactam antimicrobials was largely attributable to the predominant healthcare-associated MRSA (HA-MRSA) clone ST22-IV [2B] (EMRSA-15), and to the community-associated MRSA (CA-MRSA) clone ST45-V [5C2&5], which has acquired resistance to multiple antimicrobials including ciprofloxacin, clindamycin, erythromycin, gentamicin, and tetracycline. Overall, 89.6% of methicillin-resistant SAB episodes were caused by CA-MRSA clones. Although polyclonal, approximately 72% of CA-MRSA clones were characterised as ST93-IV [2B] (Queensland clone), ST5-IV [2B], ST45-V [5C2&5], ST8-IV [2B], ST30-IV [2B], ST1-IV [2B], ST6-IV [2B], ST97-IV [2B] and Panton-Valentine leucocidin positive ST22-IV [2B]. As CA-MRSA is well established in the Australian community, it is important to monitor antimicrobial resistance patterns in community- and healthcare-associated SAB, as this information will guide therapeutic practices in treating S. aureus bacteraemia.