High Mortality Associated with Catabacter hongkongensis Bacteremia

Abstract

Catabacter hongkongensis is a recently described catalase-positive, motile, anaerobic, nonsporulating, Gram-positive coccobacillus that was first isolated from blood cultures of four patients from Hong Kong and Canada. Although DNA sequences representing C. hongkongensis have been detected in environmental sources, only one additional case of human infection has been reported, in France. We describe five cases of C. hongkongensis bacteremia in Hong Kong, two presenting with sepsis, one with acute gangrenous perforated appendicitis, one with acute calculous cholecystitis, and one with infected carcinoma of colon. Three patients, with gastrointestinal malignancy, died during admission. All five isolates were catalase positive, motile, and negative for indole production and nitrate reduction and produced acid from arabinose, glucose, mannose, and xylose. They were unambiguously identified as C. hongkongensis by 16S rRNA gene analysis. Of the total of 10 reported cases of C. hongkongensis bacteremia in the literature and this study, most patients had underlying diseases, while two cases occurred in healthy young individuals with acute appendicitis. Six patients presented with infections associated with either the gastrointestinal or biliary tract, supporting the gastrointestinal tract as the source of bacteremia. C. hongkongensis bacteremia is associated with a poor prognosis, with a high mortality of 50% among reported cases, especially in patients with advanced malignancies. All reported isolates were susceptible to metronidazole. Identification of more C. hongkongensis isolates by 16S rRNA gene sequencing will help better define its epidemiology and pathogenesis.

Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry for identification of clinically significant bacteria that are difficult to identify in clinical laboratories

“…Spectra were analysed with MALDI Biotyper 3.0 and Reference Library V.3.1.2.0 (Bruker Daltonik). Since Catabacter hongkongensis is not represented in the Bruker Daltonik database, two additional C hongkongensis strains were later added 52. The MALDI Biotyper output is a log (score) in the range 0–3.0.…”

First case of human bacteraemia by Catabacter hongkongensis in Scandinavia

“…The tetracycline resistance gene tet(32) was detected in the genome of Catabacter hongkongensis HKU16 T on position 698 906 to 700 825, which corresponds to 1920 bases with an identity of 100%. Furthermore, cefotaxime resistance was reported for strain HKU16 T [2]. No resistance genes were detected in the genome of strain ABBA15k.…”

“…[1] in Hong Kong in 2007. This bacterial species was also detected in human specimens in British Columbia, Canada, in 2012 [2], and in Poitiers, France, in 2011 [3]. The isolation of C. hongkongensis in clinical laboratories is rare, and no case reports have been published after 2012.…”

“…The isolation of C. hongkongensis in clinical laboratories is rare, and no case reports have been published after 2012. C. hongkongensis is supposed to be a human pathogen, with high mortality reported among patients with underlying disease [2]. Nothing is known about the transmission of this species, and little is known about its environmental occurrence.…”

Gene Amplification and Sequencing for Bacterial Identification

“…As a result of the easy access to clinical specimens, the oral cavity and the gastrointestinal tract are the most important sources for bacterial discovery in humans Woo, Tse, Lau, et al, 2005;Woo, Wong, et al, 2010;Woo et al, 2014;Yuen et al, 2001). The use of 16S rRNA gene sequencing for detection has also facilitated downstream studies of these novel bacteria to help understand their disease associations, pathogenicity, transmission routes and potential reservoir(s) (Couturier, Slechta, Goulston, Fisher, & Hanson, 2012;Curreem et al, 2011;Elsendoorn, Robert, Culos, Roblot, & Burucoa, 2011;Faibis et al, 2008;Kim et al, 2011;Lau, Fan, et al, 2012Lau et al, 2005Lau et al, , 2009Lau, McNabb, et al, 2007;Lau, Wong, Li, Woo, & Yuen, 2008;Lau, Woo, Fan, Lee, et al, 2007;Lau, Woo, Fan, Ma, et al, 2007;Lau, Woo, Hui, et al, 2003;Ni et al, 2007;Smith, Pandey, & Ussher, 2012;Tang et al, 2013;Teng, Huang, et al, 2014;Teng et al, 2005;Uckay et al, 2007;Woo, Kuhnert, et al, 2003;Woo, Lau, Teng, & Yuen, 2005;Woo, Ma, et al, 2005Woo, Tam, et al, 2002;Woo, Teng, Lau, & Yuen, 2006;Woo, Teng, et al, 2004Woo, Wong, et al, 2010;Woo et al, 2014;Xiong et al, 2014;Yuen et al, 2001).…”