The University of Western Australia
Meningococcal carriage in Perth university students over a 6 month period, 2018
Neisseria meningitidis (Nm) is usually an asymptomatic coloniser of the upper respiratory tract but can cause meningitis and septicaemia in susceptible individuals. It predominantly colonises the 15-23 yr old age group and outside this demographic, carriage is rare. Since 2013, most invasive meningococcal disease (IMD) has been caused by serogroup W N. meningitidis (MenW). To interrupt transmission in the community, a vaccination campaign of the ACYW meningococcal vaccine was implemented in the 15-19 yr old age group in 2017 and 2018. However, rates of IMD did not decline in 2018 and the program was extended to include children under the age of 5 yrs old in 2019. One consideration for the vaccination implementation strategy was the low coverage of the 19-23 yr old age group. To understand whether this group was a significant reservoir for meningococcal carriage, a pilot study was conducted in two cohorts of university students at two time points of low and high incidence of IMD during 2018. The first collection of four hundred throat swabs were collected from a single cohort of university students at UWA in March over a two week period concurrently with low IMD incidence. The second collection of 1200 throat swabs was obtained from university students attending residential colleges at Edith Cowen University, Murdoch University, Curtin University and UWA over four weeks in concurrently with a period of high IMD incidence. The swabs were processed immediately after collection for the detection of N. meningitidis by culture and RT-PCR. For both collections, the rate of carriage was similar at 16%. Approximately 20% of detections in both periods were genogrouped to CYW while the remaining 80% were non-serogroupable. Eighty four isolates were completely sequenced and assigned to clonal complexes. Of these 35.7% belonged to genetic lineages involved in invasive disease and were mostly serogroup B or Y. In conclusion, we found that there were high levels of meningococcal carriage in university students and that these isolates were predominantly not matched to the ACYW vaccine.
Dr Charlene Kahler completed a Bachelor of Science and PhD in microbiology at the University of Queensland. Her first post-doctoral position was at Emory University in Atlanta (USA) with Prof David Stephens where she developed her interest in meningococcal pathogenesis. She returned to Australia in 1999 as the Faculty of Medicine Fellow at Monash University to work with Prof John Davies on Neisseria gonorrhoeae. In 2005, she became a senior lecturer at The University of Western Australia.