Unlike Elizabethkingia meningoseptica, the clinical importance of E. anophelis is poorly understood. We determined the clinical and molecular epidemiology of bacteremia caused by Elizabethkingia-like species from five regional hospitals in Hong Kong. Among 45 episodes of Elizabethkingia-like bacteremia, 21 were caused by Elizabethkingia, including 17 E. anophelis, three E. meningoseptica and one E. miricola; while 24 were caused by other diverse genera/species, as determined by 16S rRNA gene sequencing. Of the 17 cases of E. anophelis bacteremia, 15 (88%) were clinically significant. The most common diagnosis was pneumonia (n = 5), followed by catheter-related bacteremia (n = 4), neonatal meningitis (n = 3), nosocomial bacteremia (n = 2) and neutropenic fever (n = 1). E. anophelis bacteremia was commonly associated with complications and carried 23.5% mortality. In contrast, of the 24 episodes of bacteremia due to non-Elizabethkingia species, 16 (67%) were clinically insignificant. Compared to non-Elizabethkingia bacteremia, Elizabethkingia bacteremia was associated with more clinically significant infections (P < 0.01) and positive cultures from other sites (P < 0.01), less polymicrobial bacteremia (P < 0.01), and higher complication (P < 0.05) and mortality (P < 0.05) rates. Elizabethkingia bacteremia is predominantly caused by E. anophelis instead of E. meningoseptica. Elizabethkingia bacteremia, especially due to E. anophelis, carries significant morbidity and mortality, and should be considered clinically significant unless proven otherwise.

Genome sequencing can provide rapid insights on transmission and pathogenesis of emerging pathogens.

Laribacter hongkongensis is a newly discovered Gram-negative bacillus of the Neisseriaceae family associated with freshwater fish–borne gastroenteritis and traveler's diarrhea. The complete genome sequence of L. hongkongensis HLHK9, recovered from an immunocompetent patient with severe gastroenteritis, consists of a 3,169-kb chromosome with G+C content of 62.35%. Genome analysis reveals different mechanisms potentially important for its adaptation to diverse habitats of human and freshwater fish intestines and freshwater environments. The gene contents support its phenotypic properties and suggest that amino acids and fatty acids can be used as carbon sources. The extensive variety of transporters, including multidrug efflux and heavy metal transporters as well as genes involved in chemotaxis, may enable L. hongkongensis to survive in different environmental niches. Genes encoding urease, bile salts efflux pump, adhesin, catalase, superoxide dismutase, and other putative virulence factors—such as hemolysins, RTX toxins, patatin-like proteins, phospholipase A1, and collagenases—are present. Proteomes of L. hongkongensis HLHK9 cultured at 37°C (human body temperature) and 20°C (freshwater habitat temperature) showed differential gene expression, including two homologous copies of argB, argB-20, and argB-37, which encode two isoenzymes of N-acetyl-L-glutamate kinase (NAGK)—NAGK-20 and NAGK-37—in the arginine biosynthesis pathway. NAGK-20 showed higher expression at 20°C, whereas NAGK-37 showed higher expression at 37°C. NAGK-20 also had a lower optimal temperature for enzymatic activities and was inhibited by arginine probably as negative-feedback control. Similar duplicated copies of argB are also observed in bacteria from hot springs such as Thermus thermophilus, Deinococcus geothermalis, Deinococcus radiodurans, and Roseiflexus castenholzii, suggesting that similar mechanisms for temperature adaptation may be employed by other bacteria. Genome and proteome analysis of L. hongkongensis revealed novel mechanisms for adaptations to survival at different temperatures and habitats.

h Although tuberculosis (TB) is a reemerging disease that affects people in developing countries and immunocompromised populations in developed countries, the current diagnostic methods are far from optimal. Metabolomics is increasingly being used for studies on infectious diseases. We performed metabolome profiling of plasma samples to identify potential biomarkers for diagnosing TB. We compared the plasma metabolome profiles of TB patients (n ‫؍‬ 46) with those of community-acquired pneumonia (CAP) patients (n ‫؍‬ 30) and controls without active infection (n ‫؍‬ 30) using ultrahigh-performance liquid chromatographyelectrospray ionization-quadrupole time of flight mass spectrometry (UHPLC-ESI-QTOFMS). Using multivariate and univariate analyses, four metabolites, 12R-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid [12(R)-HETE], ceramide (d18:1/16:0), cholesterol sulfate, and 4␣-formyl-4␤-methyl-5␣-cholesta-8-en-3␤-ol, were identified and found to have significantly higher levels in TB patients than those in CAP patients and controls. In a comparison of TB patients and controls, the four metabolites demonstrated area under the receiver operating characteristic curve ( T uberculosis (TB) is a disease caused by the bacterium Mycobacterium tuberculosis. Although it is a well-known disease that has been around for much of human history, there are still millions of new TB cases occurring per year worldwide, and TB remains a leading cause of deaths worldwide, especially in developing countries. Since the 1980s, TB has reemerged as a result of the AIDS epidemic and increasing use of immunosuppressants. In recent years, a higher incidence of extrapulmonary disease in immunocompromised hosts and the emergence of multidrug-resistant strains have further complicated diagnosis and treatment (1-3). Despite the medical importance of TB, diagnosis is still associated with many unresolved problems. The traditional gold standard methods are smear and culture for acid-fast bacilli from clinical specimens. Although culture offers higher sensitivity and specificity than those of smears, it is not useful for culture-negative cases, especially in early, disseminated, or extrapulmonary disease (4, 5). Moreover, it often takes 2 to 6 weeks before culture is positive and even longer for definitive species identification. While newer diagnostic modalities, such as adenosine deaminase levels in pleural fluid, lipoarabinomannan levels in urine, PCR, and Xpert MTB/RIF assays, have been developed (6-12), there are still limitations in terms of their sensitivity and/or specificity.Metabolomics is an emerging platform for studies of infectious diseases or pathogens (13)(14)(15)(16)(17)(18)(19). For TB, the technique has been applied on cultured isolates for differentiation from other Mycobacterium species and studies on the biology and virulence of tuberculosis (14,15,(20)(21)(22). For example, lipidomics studies have revealed novel metabolites potentially associated with growth and virulence of M. tuberculosis (23,24). We also recently identified ...