Raena Kaur¹, Benjamin Palladino¹, John Dyer¹, Edward Raby^{1, 2} 

¹Department of Infectious Diseases, Fiona Stanley Hospital, WA, Australia
²Department of Microbiology, PathWest, Fiona Stanley Hospital, WA, Australia
 

Inhaling airborne spores of the ubiquitous environmental mold Aspergillus can uncommonly cause a spectrum of pulmonary diseases, of which invasive aspergillosis (IA) is one of the most severe.¹ IA diagnosis is challenging owing to absent or non-specific clinical manifestations, non-pathognomonic radiology, and limited sensitivity of respiratory cultures. Fungal diagnostic advances beyond tissue histopathology and culture-based mycological methods include the non-invasive fungal biomarker galactomannan (GM). GM is produced by the Aspergillus cell wall, and can be tested in serum and bronchoalveolar lavage (BAL) fluid with high sensitivity. Bio-Rad’s Platelia Aspergillus ELISA GM assay is widely used, but several exposure factors including antibiotics, foods and nutrients, blood products, and non-Aspergillus fungi can cause result cross-reaction.^{2, 3}

 

An immunocompetent female with significant vape use experienced hypoxic respiratory failure, with extensive bilateral peribronchial nodular and ground glass densities on chest HRCT. Serum and BAL GM were highly elevated, but further testing including lung cryobiopsy failed to demonstrate Aspergillus. Ultimately her presentation was most compatible with e-cigarette or vaping-associated lung injury (EVALI), however given diagnostic uncertainty we recommended IA treatment. This case highlights ongoing clinical challenges in GM application, particularly in emergent pulmonary pathologies, and consequent ‘erring on the side of caution’ when facing diagnostic dilemmas.

1.       Latgé JP, Chamilos G. Aspergillus fumigatus and Aspergillosis in 2019. Clin Microbiol Rev. 2019;33(1).

2.       Hung YH, Lai HH, Lin HC, Sun KS, Chen CY. Investigating Factors of False-Positive Results of Aspergillus Galactomannan Assay: A Case-Control Study in Intensive Care Units. Front Pharmacol. 2021;12:747280.

3.       Adam O, Aupérin A, Wilquin F, Bourhis J-H, Gachot B, Chachaty E. Reply to Penack et al. and Wu. Clinical Infectious Diseases. 2004;39(9):1402-3.

Helen M. Tang¹, Catriona L. Halliday¹, Kerri Basile¹, Sharon C.-A. Chen^{1, 2, 3}

¹Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital, Westmead, NSW 2145, Australia; ²Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia; ³Sydney Infectious Diseases Institute, The University of Sydney, Westmead, NSW 2145, Australia

Mucormycosis is a life-threatening infection associated with high morbidity and mortality. Conventional diagnostic methods are limited by low sensitivity and prolonged turnaround times, while commercial polymerase chain reaction (PCR) assays are costly and lack genus/species-specific targets. We developed a novel molecular diagnostic workflow to facilitate the rapid detection of Mucorales directly from clinical specimens. This workflow integrates two in-house in vitro diagnostic (IVD) PCR assays: a real-time Pan-Mucorales PCR, followed by a real-time, multiplex genus/species-specific PCR targeting Rhizopus arrhizus, Rhizopus microsporus, and Mucor spp. Specificity was validated using culture isolates of Mucorales, non-Mucorales fungi, and bacteria. 165 clinical specimens (69 Mucorales-positive and 96 negative), confirmed by an in-house panfungal PCR and DNA sequencing, were used to evaluate the PCR assays. The Pan-Mucorales PCR demonstrated 98.6% sensitivity and 100% specificity, while the multiplex genus/species-specific PCR assay achieved sensitivities of 93.8% for R. arrhizus, 70.8% for R. microsporus, and 75% for Mucor spp., each with 100% specificity. Concordance with the panfungal PCR and sequencing protocol was high, supporting the robustness of the workflow. This novel diagnostic approach has the potential to significantly reduce turnaround times, labour, and costs, aiming to streamline the diagnostic process and improve patient outcomes through timely, precise diagnostics. 

Isaac Freelander¹, Michael Findlay

¹Department of Microbiology, NSW Health Pathology, Kingswood, NSW, Australia 

Ochrobactrum anthropi is a non-fermentative gram-negative bacillus in the Brucellaceae family, which is increasingly being recognised as an opportunistic pathogen. Despite its low virulence, due to its ubiquity and persistence in the environment, this organism has been implicated in a wide range of infections including catheter-associated bacteraemia, endocarditis, osteomyelitis and meningitis.¹ Treatment may be complicated by broad-spectrum beta-lactam resistance, mediated by a chromosomal AmpC-like beta-lactamase.² We describe an episode of Ochrobactrum anthropi bacteraemia in an immunocompetent host, in what we believe to be the first case associated with ozone therapy reported in the literature. After an initial period of septic shock requiring vasopressor support, the patient was ultimately switched to ciprofloxacin therapy and made a complete recovery. This case highlights the diagnostic and treatment challenges associated with the isolation of rare pathogens, and the pressing need for ongoing regulation of alternative therapies.

References:

1. Hagiya H, Ohnishi K, Maki M, et al. Clinical characteristics of Ochrobactrum anthropi bacteremia. J Clin Microbiol. 2013; 51(4): 1330-3.

2. Nadjar D, Labia R, Cerceau C, et al. Molecular characterization of chromosomal class C beta-lactamase and its regulatory gene in Ochrobactrum anthropi. Antimicrob Agents Chemother. 2001; 45(8): 2324-30.

Abhinav Rajkumar¹, Philip N Britton^{2, 3}
 

¹ Department of Microbiology, The Prince of Wales Hospital

² Department of Infectious Diseases and Microbiology, The Children's Hospital at Westmead

³ Sydney ID, Sydney Medical School, University of Sydney

 

This case was an Australian-born 4-year-old child who had grown up on a rural farm who presented with 2 months’ of cough, shortness of breath, lethargy, reduced appetite and weight loss. On examination, body weight was below the normal range (< 1^st centile) and right-sided reduced breath sounds and pulmonary percussion dullness were noted. Chest imaging demonstrated diffuse right-sided opacification with two large cystic pulmonary lesions in the right hemithorax. Whilst being intubated and receiving positive pressure ventilation for planned lesion biopsy, a pulmonary cyst ruptured. Clinically, cyst rupture manifested with hypoxemia, bronchoconstriction, increased pulmonary ventilatory requirements and hypotension, indicative of an anaphylactoid reaction. Subsequently, the child required chest drain placement, drainage of cystic and pulmonary fluid, fluid resuscitation, vasopressor therapy including an adrenaline infusion, mechanical ventilation and admission to the intensive care unit. Microscopy of aspirated cystic fluid and bronchial fluid showed hooklets and protoscolices consistent with Echinococcus species. A diagnosis of pulmonary hydatid disease was made, and the child received albendazole[PB1]  andshowed clinical recovery with close ongoing monitoring. Hydatid serology performed retrospectively on serum tested negative. This case highlights the importance of early suspicion and diagnosis of pulmonary hydatid disease to direct appropriate management and minimise complications. 

Discrepancy in malaria LAMP testing

Allisa Robertson^1
1Royal Darwin Hospital

A case of Australian-acquired neurosparganosis causing cauda equina syndrome was confirmed with nucleic acid amplification testing using pan-cestode primers. Complete surgical removal was not possible. Treatment with a 3 day course of praziquantel was complicated by neurological deterioration suggestive of a paradoxical inflammatory response. Recrudescence of disease occurred within a couple of years with new intraventricular and cerebral disease causing obstructive hydrocephalus requiring decompressive craniotomy and ventriculo-peritoneal shunt insertion. High dose praziquantel was prescribed with prophylactic dexamethasone. Treatment is planned to continue until resolution of radiological findings that are suggestive of active infection. 

Certificate to be awarded - panel to judge