Rikki M.A. Graham

Mild illness during outbreak of Shiga toxin−producing Escherichia coli O157 infections associated with agricultural show, Australia

During a large outbreak of Shiga toxin−producing Escherichia coli illness associated with an agricultural show in Australia, we used whole-genome sequencing to detect an IS1203v insertion in the Shiga toxin 2c subunit A gene of Shiga toxin−producing E. coli. Our study showed that clinical illness was mild, and hemolytic uremic syndrome was not detected.

Sequence Analysis of Toxin Gene–Bearing Corynebacterium diphtheriae Strains, Australia

By conducting a molecular characterization of Corynebacterium diphtheriae strains in Australia, we identified novel sequences, nonfunctional toxin genes, and 5 recent cases of toxigenic cutaneous diphtheria. These findings highlight the importance of extrapharyngeal infections for toxin gene–bearing (functional or not) and non–toxin gene–bearing C. diphtheriae strains. Continued surveillance is recommended.

Evaluation of the SHIGA TOXIN QUIK CHEK and ImmunoCard STAT! EHEC as screening tools for the detection of Shiga toxin in fecal specimens

In this study we evaluated the performance of the SHIGA TOXIN QUIK CHEK (Techlab®, Blacksburg, VA) and the ImmunoCard STAT! Enterohaemorrhagic E. coli (EHEC) (Meridian BioScience, Cincinnati, OH, USA) assays as methods for qualitatively detecting the presence of Shiga toxin in human fecal specimens. A multiplex PCR for the detection of stx1 and stx2 was used as the standard for comparison. The SHIGA TOXIN QUIK CHEK detected all known Shiga toxin subtypes with the exception of Stx2f, while the ImmunoCard STAT! EHEC was unable to identify four of the seven Stx2 subtypes, including Stx2b and Stx2d. When compared to multiplex PCR based on Shiga toxin gene presence alone both assays demonstrated 100% specificity, and gave sensitivity values of 50.0% and 41.2% respectively. Correlation between each assay and the multiplex PCR was calculated by the use of kappa, with both assays exhibiting a moderate level of agreement.

A severe transmissible Majocchi's granuloma in an immunocompetent returned traveler

Severe dermatophyte infection is rare in immunocompetent adults. Recently cases have been described in travelers returning from South East Asia (Luchsinger et al., 2015) [1]. These may be sexually transmitted and can have permanent sequelae. We describe the first reported case of Majocchis granuloma (MG) in an Australian returned traveler and its subsequent transmission via sexual contact. Both patients were successfully treated with systemic antifungals. MG should be considered in patients with severe rash after travel to South East Asia.

Outbreak of health care-associated Burkholderia cenocepacia bacteremia and infection attributed to contaminated sterile gel used for central line insertion under ultrasound guidance and other procedures

Background: We report an outbreak of Burkholderia cenocepacia bacteremia and infection in 11 patients predominately in intensive care units caused by contaminated ultrasound gel used in central line insertion and sterile procedures within 4 hospitals across Australia. Methods: Burkholderia cenocepacia was first identified in the blood culture of a patient from the intensive care unit at the Gold Coast University Hospital on March 26, 2017, with 3 subsequent cases identified by April 7, 2017. The outbreak response team commenced investigative measures. Results: The outbreak investigation identified the point source as contaminated gel packaged in sachets for use within the sterile ultrasound probe cover. In total, 11 patient isolates of B cenocepacia with the same multilocus sequence type were identified within 4 hospitals across Australia. This typing was the same as identified in the contaminated gel isolate with single nucleotide polymorphism‐based typing, demonstrating that all linked isolates clustered together. Conclusion: Arresting the national point‐source outbreak within multiple jurisdictions was critically reliant on a rapid, integrated, and coordinated response and the use of informal professional networks to first identify it. All institutions where the product is used should look back at Burkholderia sp blood culture isolates for speciation to ensure this outbreak is no larger than currently recognized given likely global distribution.

Comparative genomics identifies distinct lineages of S. Enteritidis from Queensland, Australia

Salmonella enterica is a major cause of gastroenteritis and foodborne illness in Australia where notification rates in the state of Queensland are the highest in the country. S. Enteritidis is among the five most common serotypes reported in Queensland and it is a priority for epidemiological surveillance due to concerns regarding its emergence in Australia. Using whole genome sequencing, we have analysed the genomic epidemiology of 217 S. Enteritidis isolates from Queensland, and observed that they fall into three distinct clades, which we have differentiated as Clades A, B and C. Phage types and MLST sequence types differed between the clades and comparative genomic analysis has shown that each has a unique profile of prophage and genomic islands. Several of the phage regions present in the S. Enteritidis reference strain P125109 were absent in Clades A and C, and these clades also had difference in the presence of pathogenicity islands, containing complete SPI-6 and SPI-19 regions, while P125109 does not. Antimicrobial resistance markers were found in 39 isolates, all but one of which belonged to Clade B. Phylogenetic analysis of the Queensland isolates in the context of 170 international strains showed that Queensland Clade B isolates group together with the previously identified global clade, while the other two clades are distinct and appear largely restricted to Australia. Locally sourced environmental isolates included in this analysis all belonged to Clades A and C, which is consistent with the theory that these clades are a source of locally acquired infection, while Clade B isolates are mostly travel related.

Detection of Spotted Fever Group Rickettsia DNA by Deep Sequencing

After conventional molecular and serologic testing failed to diagnose the cause of illness, deep sequencing identified spotted fever group Rickettsia DNA in a patient’s blood sample. Sequences belonged to R. honei, the causative agent of Flinders Island spotted fever. Next-generation sequencing is proving to be a useful tool for clinical diagnostics.

Genetic Characterization of a Neisseria meningitidis cluster in Queensland, Australia

Neisseria meningitidis serogroups B and C have been responsible for the majority of invasive meningococcal disease in Australia, with serogroup B strains causing an increasing proportion of cases in recent years. Serogroup Y has typically caused sporadic disease in Australia. In 2002, a cluster of 4 cases was reported from a rural region in Queensland. Three of these cases were serogroup C, with 1 case diagnosed by molecular detection only, and the fourth case was identified as a serogroup Y infection. Genomic analysis, including antigen finetyping, multilocus sequence typing (MLST), and core genome MLST, demonstrated that the serogroup Y case, though spatially and temporally linked to a serogroup C disease cluster, was not the product of a capsule switch and that one of the serogroup C isolates had a deletion of the entire porA sequence.