Laribacter hongkongensis Isolated from a Patient with Community-Acquired Gastroenteritis in Hangzhou City

Abstract

We describe the isolation of Laribacter hongkongensis in Hangzhou City, People's Republic of China. One strain of bacterium, named LHHZ242, had many of the same phenotypic and genotypic characteristics as Laribacter hongkongensis described in previous publications. This discovery proves that Laribacter hongkongensis is also associated with community-acquired gastroenteritis outside Hong Kong.Laribacter hongkongensis was first isolated from the blood and empyemic pus of a 57-year-old Chinese man with alcoholic cirrhosis and bacterial thoracic empyema in Hong Kong in 2001. Thereafter, this newly discovered bacterium was isolated from the stools of three Asian patients and three European patients with community-acquired diarrhea in Hong Kong (5). This bacillus is a facultative anaerobic, motile, non-spore forming, nonfermentative, urease positive, gram negative, and seagull shaped and belongs to the family Neisseriaceae of the ␤ subclass of the class Proteobacteria (7). Patrick Woo and colleagues reported on a case-control study that showed the presence of an association between L. hongkongensis and community-acquired diarrhea, the consumption of fish, and travel (6). No reports of the isolation of L. hongkongensis outside Hong Kong in the past 5 years have yet been published. In order to determine whether Laribacter hongkongensis is related to some community-acquired cases of gastroenteritis outside of Hong Kong, a study was carried out with patients with communityacquired gastroenteritis in Hangzhou First People's Hospital in the city of Hangzhou, People's Republic of China, by using modified cefoperazone MacConkey (Mϩ) agar.All fecal swabs in our study were freshly collected from outpatients with community-acquired diarrhea in an outpatient service at Hangzhou First People's Hospital from August to November 2005. The specimens were directly inoculated in six culture agars: xylosine-lysine-deoxycholate (XLD) agar, thiosulfate-citrate-bile salts-sucrose (TCBS) agar, salmonellashigella (SS) agar, campylobacter blood-free selective agar (CCDA), MacConkey agar, and Mϩ agar. Modified cefoperazone MacConkey agar was cefoperazone MacConkey agar (1) in which the original concentration was reduced by 50% (final cefoperazone concentration, 16 mg/liter). The cultures were incubated under aerobic conditions at 37°C for 48 h on XLD, TCBS, SS, and Mϩ agars. The CCDA cultures were incubated in 5 to 10% CO 2 at 37°C for 48 h. Small and colorless colonies that grew on MacConkey and Mϩ agars but that did not grow on XLD agar, TCBS agar, SS agar, or CCDA or that grew very poorly on those agars were picked out. Among these bacterial colonies, all oxidase-, arginine-, and urease-positive bacteria were screened out.Among 275 stool samples tested, one strain of bacterium, named LHHZ242, that was positive by the oxidase, arginine, and Christensen urea agar tests was isolated from the stool of one patient. It was a seagull-shaped, gram-negative, and non-sporeforming bacterium that grew on Mϩ agar as a colorless colony 1 mm in diameter. T...

Plasmid profile and construction of a small shuttle vector in Laribacter hongkongensis

“…Isolation of L. hongkongensis from patients in or have recently travelled to Asia, Europe, America, and Africa implied that the bacterium is probably of global importance (Woo et al , 2005a. Recently, L. hongkongensis has also been reported from another coastal province in mainland China (Ni et al 2007). Although the causative role of L. hongkongensis in gastroenteritis is yet to be established (Farmer et al 2004), these data provide strong evidence that the bacterium is a potential diarrheal pathogen that warrants further investigations.…”

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).…”

Two-dimensional gel electrophoresis in bacterial proteomics

“…L. hongkongensis is a recently discovered β-Proteobacterium that is associated with community-acquired gasteroenteritis and traveler's diarrhea (Yuen et al, 2001;Woo et al, 2004;Woo et al, 2005). It can inhabit in the intestines of freshwater fish, frogs and humans, and can also grow independently in freshwater environments (Woo et al, 2004;Teng et al, 2005;Lau et al, 2007;Ni et al, 2007;Lau et al, 2009). Therefore it needs to cope with varying environmental temperatures in these different growth habitats.…”