Matthew B Eustace^1,2, Maxwell Braddick¹, Kylie Alcorn³, Keat Choong⁴, Ferris Satyaputra⁵, David Siebert⁶, Simon Smith⁷, Ryan Sommerville⁸, Kate McCarthy^1,2

¹Infectious Diseases Unit, Royal Brisbane & Women’s Hospital, Brisbane, Australia; ²Central Microbiology Laboratory, Pathology Queensland, Brisbane, Australia; ³Infectious Diseases Unit, Gold Coast University Hospital, Gold Coast, Australia; ⁴Infectious Diseases Unit, Sunshine Coast University Hospital, Sunshine Coast, Australia; ⁵Infectious Diseases Unit, Townsville University Hospital, Townsville, Australia; ⁶Infection Management Service, Princess Alexandra Hospital, Brisbane, Australia; ⁷Infectious Diseases Unit, Cairns Hospital, Cairns, Australia; ⁸Otolaryngology Unit, Royal Brisbane & Women’s Hospital, Brisbane, Australia

Background: Central skull base osteomyelitis (CSBO) is an uncommon, life-threatening infection of the bones of the cranial vault. Commonly infection is spread contiguously from non-sterile sites, including the otogenic, paranasal, sinus and odontogenic routes with varied microbiology reported to date. Here we describe the underlying microbiology of CSBO in Queensland, Australia, over an 11-year period.

Methods: Medical record coding enquiries identified cases of CSBO across 6 tertiary hospitals in Queensland, Australia, from January 2010 to December 2020¹. Microbiological data including sample type, culture, and susceptibility testing was obtained for each case.

Results: Twenty-two cases of CSBO were identified within the study period. Six cases had bone sampling for microbiological diagnosis while the remainder had superficial sampling of contiguous structures. The most common pathogen isolated was Pseudomonas aeruginosa followed by Staphylococcus aureus, with only 1 case of fungal infection, where Aspergillus flavus was isolated.

Discussion: Microbiological diagnoses relied primarily on superficial sampling of contiguous, non-sterile sites. Whether the isolated organisms were representative of the underlying pathogen or reflected colonising flora was difficult to determine. Close collaboration between surgeons, physicians and the microbiology laboratory is critical to support accurate interpretation of microbiological results which can better inform both medical and surgical management.

1.    Eustace MB et al, Central Skull Base Osteomyelitis in Queensland, Australia, 2010–2020, Open Forum Infectious Diseases, Volume 11, Issue 10, October 2024

Contribution Statement: All authors were involved in the conceptualisation of the study and data collection. MBE undertook the analysis, wrote the manuscript, conceptualised the microbiological sub-analysis, analysed the data and drafted the abstract/poster.