Salmonella typhi central nervous system infection

This report aims to document Salmonella typhi as a cause of central nervous system infection

Defining the phylogenetics and resistome of the major clostridioides difficile ribotypes circulating in Australia

Clostridioides difficile infection (CDI) remains a significant public health threat globally. New interventions to treat CDI rely on an understanding of the evolution and epidemiology of circulating strains. Here we provide longitudinal genomic data on strain diversity, transmission dynamics and antimicrobial resistance (AMR) of C. difficile ribotypes (RTs) 014/020 (n=169), 002 (n=77) and 056 (n=36), the three most prominent C. difficile strains causing CDI in Australia. Genome scrutiny showed that AMR was uncommon in these lineages, with resistance-conferring alleles present in only 15/169 RT014/020 strains (8.9 %), 1/36 RT056 strains (2.78 %) and none of 77 RT002 strains. Notably, ~90 % of strains were resistant to MLSB agents in vitro, but only ~5.9 % harboured known resistance alleles, highlighting an incongruence between AMR genotype and phenotype. Core genome analyses revealed all three RTs contained genetically heterogeneous strain populations with limited evidence of clonal transmission between CDI cases. The average number of pairwise core genome SNP (cgSNP) differences within each RT group ranged from 23.3 (RT056, ST34, n=36) to 115.6 (RT002, ST8, n=77) and 315.9 (RT014/020, STs 2, 13, 14, 49, n=169). Just 19 clonal groups (encompassing 40 isolates), defined as isolates differing by ≤2 cgSNPs, were identified across all three RTs (RT014/020, n=14; RT002, n=3; RT056, n=2). Of these clonal groups, 63 % (12/19) comprised isolates from the same Australian State and 37 % (7/19) comprised isolates from different States. The low number of plausible transmission events found for these major RTs (and previously documented populations in animal and environmental sources/reservoirs) points to widespread and persistent community sources of diverse C. difficile strains as opposed to ongoing nationwide healthcare outbreaks dominated by a single clone. Together, these data provide new insights into the evolution of major lineages causing CDI in Australia and highlight the urgent need for enhanced surveillance, and for public health interventions to move beyond the healthcare setting and into a One Health paradigm to effectively combat this complex pathogen

Rapid Detection and Sequence-Specific Differentiation of Extended-Spectrum β-Lactamase GES-2 from Pseudomonas aeruginosa by Use of a Real-Time PCR Assay

The LightCycler was compared to nested PCR for the detection of bla(GES/IBC) genes from 100 Pseudomonas aeruginosa clinical isolates. The real-time PCR assay detected a bla(GES/IBC) gene product from 83 isolates, exhibiting a sensitivity and specificity of 94.3 and 100% respectively, compared to nested PCR and DNA sequencing

Mycobacterial inactivation protein extraction protocol for matrix-assisted laser desorption ionization time-of-flight characterization of clinical isolates

Background: Rapid identification of mycobacteria has been made possible with matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) in recent years. Working with high concentrations of mycobacteria in a PC-3 containment facility makes MALDI-TOF cumbersome and costly. Therefore removing the inactivated isolate's protein extract from the PC-3 facility is needed for efficient identification in a routine PC-2 laboratory. Methods: This work describes a novel chemical and mechanical disruption protein extraction method, which provides reliable MALDI-TOF results from solid and liquid media, while ensuring laboratory safety. Results: When compared to sequencing results, 93.9% of the clinical isolates were identified in LJ media and 89% of the clinical isolates were identified in MGIT media. Conclusion: The MIPE protocol produces a high quality protein extract with improved isolate identification without compromising result turn-around-times or laboratory safety

First human case of fatal halicephalobus gingivalis meningoencephalitis in Australia

Halicephalobus gingivalis (previously Micronema deletrix) is a free-living nematode known to cause opportunistic infections, mainly in horses. Human infections are very rare, but all cases described to date involved fatal meningoencephalitis. Here we report the first case of H. gingivalis infection in an Australian human patient, confirmed by nematode morphology and sequencing of ribosomal DNA. The implications of this case are discussed, particularly, the need to evaluate real-time PCR as a diagnostic tool