Identification of the first erm(B)-positive Campylobacter jejuni and Campylobacter coli associated with novel multidrug resistance genomic islands in Australia

OBJECTIVES

This report describes the first identification of two Campylobacter isolates harbouring erm(B) in Australia.

METHODS

Two erm(B)-positive isolates, Campylobacter coli 18V1065H1 and Campylobacter jejuni 19W1001H1, were isolated from diarrhoeal faecal samples from two travellers who had recently returned from Southeast Asia. Isolates underwent whole-genome sequencing using an Illumina NextSeq system and were analysed with the Nullarbor pipeline. Antimicrobial resistance genes were identified using AMRFinderPlus and sequence types (STs) were determined by multilocus sequence typing and the PubMLST Campylobacter jejuni/coli typing scheme.

RESULTS

Besideserm(B), C. jejuni 19W1001H1 possessed six other resistance genes [aad9, aadE, aph(3')-Illa, bla_OXA-185, catA13 and tet(O)], the gyrA T86I mutation and the RE-CmeABC multidrug efflux pump variant. Campylobacter coli 18V1065H1 also possessed six resistance genes [aad9, aadE, aph(3')-IIIa, bla_OXA-61, sat4 and tet(O)] in addition to erm(B); however, this isolate lacked genetic evidence for resistance to fluoroquinolones (no gyrA mutation). The erm(B) locus differed between isolates and neither was identical to previously identified erm(B) multidrug resistance genomic island (MDRGI) types. Both erm(B)-bearing isolates belonged to novel sequence types: ST9967 (C. jejuni 19W1001H1) and ST10161 (C. coli 18V1065H1).

CONCLUSIONS

This study detected the presence oferm(B) in Campylobacter for the first time in Australia. This novel mechanism of macrolide resistance is a major concern both for human and animal health and warrants close surveillance as macrolides are often the drug of choice for treating campylobacteriosis. The erm(B) gene is associated with several MDRGIs and dissemination of this resistance mechanism will likely limit treatment options for Campylobacter infections.

Epidemic and Inter-epidemic Burden of Pediatric Human Parechovirus Infection in New South Wales, Australia, 2017-2018

BACKGROUND

Human parechovirus (HPeV) typically infects young children, and although infection is often asymptomatic, some types (eg, HPeV3) are associated with severe clinical manifestations, including central nervous system infection or sepsis-like syndrome, particularly affecting young infants. The third documented national epidemic of HPeV occurred in Australia in 2017-2018.

METHODS

Four public laboratories that perform almost all of the HPeV PCR testing in New South Wales provided data regarding HPeV tests performed from July 1, 2017 to June 30, 2018. Limited demographic and clinical data were obtained from electronic medical records for laboratory test-positive cases that presented to each of the 3 pediatric hospitals in New South Wales.

RESULTS

Five hundred eighty-one HPeV-positive samples obtained from 395 cases were included in the analysis. The peak of the outbreak occurred in late November 2017 (approximately 35 new cases each week), with the main HPeV epidemic occurring between the spring and summer months of September 2017 to January 2018; although this seasonality was observed primarily in infants less than 12 months of age. Among the 388 pediatric cases, almost half were younger than 2 months (188; 47%) and only 10 were children older than 2 years. The annualized estimated incidence of laboratory confirmed HPeV infection in children was approximately 142.4 cases per 100,000 children younger than 5 years in New South Wales during the epidemic season.

CONCLUSIONS

The large burden of HPeV infection and disease identified in young infants in this and previous Australian studies highlight the need for more comprehensive national surveillance of HPeV infections and improved prevention strategies.

Characteristics of a widespread community cluster of H275Y oseltamivir-resistant A(H1N1)pdm09 influenza in Australia

Background. Oseltamivir resistance in A(H1N1)pdm09 influenza is rare, particularly in untreated community cases. Sustained community transmission has not previously been reported.

Methods. Influenza specimens from the Asia–Pacific region were collected through sentinel surveillance, hospital, and general practitioner networks. Clinical and epidemiological information was collected on patients infected with oseltamivir-resistant viruses.

Results. Twenty-nine (15%) of 191 A(H1N1)pdm09 viruses collected between May and September 2011 from Hunter New England (HNE), Australia, contained the H275Y neuraminidase substitution responsible for oseltamivir resistance. Only 1 patient had received oseltamivir before specimen collection. The resistant strains were genetically very closely related, suggesting the spread of a single variant. Ninety percent of cases lived within 50 kilometers. Three genetically similar oseltamivir-resistant variants were detected outside of HNE, including 1 strain from Perth, approximately 4000 kilometers away. Computational analysis predicted that neuraminidase substitutions V241I, N369K, and N386S in these viruses may offset the destabilizing effect of the H275Y substitution.

Conclusions This cluster represents the first widespread community transmission of H275Y oseltamivir-resistant A(H1N1)pdm09 influenza. These cases and data on potential permissive mutations suggest that currently circulating A(H1N1)pdm09 viruses retain viral fitness in the presence of the H275Y mutation and that widespread emergence of oseltamivir-resistant strains may now be more likely.

Back to the future--the history and philosophy of medicine experiment at Sydney University

History and Philosophy of Medicine has been a compulsory unit in the first year of the medical curriculum at Sydney University for the past decade. Volunteer tutors are drawn from most clinical and basic science departments, and each year the programme is organized on a theme of current importance in medical practice. This course began as an experiment because no resources were available for specialist staff, but has proved outstandingly successful in generating both student and teaching staff interest and support for the programme. Students present short tutorial papers to their peer group followed by submission of an essay which takes into account the tutorial discussion. The open book examination includes analysis of an unseen piece of primary source material as well as questions derived from the classwork. The Faculties of Arts and Science encouraged this educational experiment and several medical students have now opted to undertake a year of historical research during the intercalated B Sci(Med) programme, and a number of the tutors have enrolled in postgraduate historial or ethical programmes. We suggest that this model may permit introduction of novel courses in times of financial cutback within the Universities, and even allow a foundation to be laid for future development.

Relationship between hepatitis B virus DNA in blood and serological markers of hepatitis B infection

The hepatitis B virus (HBV) DNA dot-hybridization assay has been introduced into clinical practice in Australia and its behaviour compared with that of the classic markers of HBV infection. A good correlation exists between the presence of HBV DNA and that of hepatitis B e antigen but the degree of dissociation between HBV DNA and the e:anti-e system was smaller than earlier studies would suggest. Patients who are seronegative for hepatitis B surface antigen (HBsAg), whether they possess anti-HBs, anti-HBc HBc (antibody to the core antigen), or neither antibody, gave uniformly negative results for the presence of HBV DNA. Theses results are different from those that were obtained from earlier studies of patients with chronic liver disease.