Hsuan Chen Wang

Clinical features of children infected with different strains of influenza B in southern Taiwan.

Background: This study was designed to determine the clinical characteristics of children infected with different strains of influenza B viruses isolated in southern Taiwan. The clinical features were compared with influenza A infection occurring in the same period. Methods: All children enrolled in the study had laboratory-confirmed infection with influenza A or B viruses. Influenza B speciation was performed by RNA extraction, cDNA synthesis, and amplification by polymerase chain reaction and sequencing. Demographic data, clinical findings, diagnoses, and outcomes were obtained. Results: During the study period, 163 strains of influenza A and 118 strains of influenza B were isolated. The Yamagata-like strains were most prevalent in 2001. New reassortant strains were identified since 2002 and became predominant in 2005 and 2006. Children with influenza B were more likely than those with influenza A to be diagnosed as upper respiratory tract infection, myositis, and gastroenteritis (P < 0.05). Children infected with Yamagata-like strains were more likely to develop lower respiratory tract infection (P < 0.05) and accounted for all cases of invasive disease. Children infected with the Victoria-like group had the longest hospital stays associated with severe bacterial superinfection. Conclusions: Currently new reassortant influenza B viruses are the predominant strains circulating in southern Taiwan. There is considerable similarity of clinical features between influenza A and B in children. The Yamagata-like strains were associated with more invasive infections. Continuous influenza virus surveillance is essential particularly in Taiwan where pandemic strains tend to appear earlier than in other countries.

Genome Sequence of a Novel Human Pathogen, Aeromonas aquariorum

Aeromonas aquariorum, a recently described species, is associated with a variety of human diseases. We present here the first genome sequence of A. aquariorum strain AAk1, which was isolated as the sole pathogen from the blood of a patient with septicemia and necrotizing fasciitis.

Characterization of glycan binding specificities of influenza B viruses with correlation with hemagglutinin genotypes and clinical features

The carbohydrate binding specificities are different among avian and human influenza A viruses and may affect the tissue tropism and transmission of these viruses. The glycan binding biology for influenza B, however, has not been systematically characterized. Glycan binding specificities of influenza B viral isolates were analyzed and correlated to hemagglutinin (HA) genotypes and clinical manifestations. A newly developed solution glycan array was applied to characterize the receptor binding specificities of influenza B virus clinical isolates from 2001 to 2007 in Taiwan. Thirty oligosaccharides which include α‐2,3 and α‐2,6 linkage glycans were subjected to analysis. The glycan binding patterns of 53 influenza B isolates could be categorized into three groups and were well correlated to their HA genotypes. The Yamagata‐like strains predominantly bound to α‐2,6‐linkage glycan (24:29, 83%) while Victoria‐like strains preferentially bound to both α‐2,3‐ and α‐2,6‐linkage glycans (13:24, 54%). A third group of viruses bound to sulfated glycans and these all belonged to Victoria‐like strains. Based on the HA sequences, Asn‐163, Glu‐198, Ala‐202, and Lys‐203 were conserved among Victoria‐like strains which may influence their carbohydrate recognition. The viruses bound to dual type glycans were more likely to be associated with the development of bronchopneumonia and gastrointestinal illness than those bound only to α‐2,6 sialyl glycans (P < 0.05). Glycan binding analyses provide additional information to monitor the antigenic shift, tissue tropism, and transmission capability of influenza B viruses, and will contribute to virus surveillance and vaccine strain selection. J. Med. Virol. 84:679–685, 2012.

Clinical Implications of Species Identification in Monomicrobial Aeromonas Bacteremia

Background Advances in Aeromonas taxonomy have led to the reclassification of aeromonads. Hereon, we aimed to re-evaluate the characteristics of Aeromonas bacteremia, including those of a novel species, Aeromonas dhakensis. Methodology/Principal Findings A retrospective study of monomicrobial Aeromonas bacteremia at a medical center in southern Taiwan from 2004–2011 was conducted. Species identification was based on rpoB sequencing. Of bacteremia of 153 eligible patients, A. veronii (50 isolates, 32.7%), A. dhakensis (48, 31.4%), A. caviae (43, 28.1%), and A. hydrophila (10, 6.5%) were the principal causative species. A. dhakensis and A. veronii bacteremia were mainly community-acquired and presented as primary bacteremia, spontaneous bacterial peritonitis, or skin and soft-tissue infection, whereas A. caviae was associated with hospital-onset bacteremia. The distribution of the AmpC β-lactamase and metallo-β-lactamase genes was species-specific: bla AQU-1, bla MOX, or bla CepH was present in A. dhakensis, A. caviae, or A. hydrophila, respectively, and bla CphA was present in A. veronii, A. dhakensis, and A. hydrophila. The cefotaxime resistance rates of the A. caviae, A. dhakensis, and A. hydrophila isolates were higher than that of A. veronii (39.5%%, 25.0%, and 30% vs. 2%, respectively). A. dhakensis bacteremia was linked to the highest 14-day sepsis-related mortality rate, followed by A. hydrophila, A. veronii, and A. caviae bacteremia (25.5%, 22.2%, 14.0%, and 4.7%, respectively; P = 0.048). Multivariate analysis revealed that A. dhakensis bacteremia, active malignancies, and a Pitt bacteremia score ≥ 4 was an independent mortality risk factor. Conclusions/Significance Characteristics of Aeromonas bacteremia vary between species. A. dhakensis prevalence and its associated poor outcomes suggest it an important human pathogen.

AQU-1, a chromosomal class C β-lactamase, among clinical Aeromonas dhakensis isolates: Distribution and clinical significance

Aeromonas dhakensis, a recently described Aeromonas sp. formerly called Aeromonas aquariorum, is associated with human infections. In this study, a chromosomal gene, blaAQU-1, was identified in A. dhakensis AAK1 that constitutes a 1143-bp open reading frame and is 87% identical to the gene encoding CepH in Aeromonas hydrophila. An Escherichia coli TOP10 cell transformant harbouring blaAQU-1 was resistant to cefotaxime but not to cefepime. mRNA expression of blaAQU-1 in the cefotaxime-resistant mutant strain AAK1m was 70-fold higher than in the wild strain AAK1. In all 16 A. dhakensis isolates (the major species of 51 consecutive Aeromonas blood isolates collected from June 1999 to June 2001) as well as in A. aquariorum MDC47(T) and A. hydrophila subsp. dhakensis LMG 19562(T), but not in the reference strains or clinical isolates of other A. hydrophila subspecies, Aeromonas caviae, Aeromonas veronii or Aeromonas enteropelogenes, blaAQU-1-related genes were detected by PCR. Overall, 13 (81%) of the 16 A. dhakensis blood isolates exhibited either cefotaxime resistance or the in vitro emergence of derepressed cefotaxime-resistant mutants. In vivo selection of an A. dhakensis resistant mutant was noted in a burn patient undergoing cefotaxime monotherapy. These observations suggest that AQU-1 is a chromosomal cephalosporinase in A. dhakensis. Cefotaxime monotherapy for severe A. dhakensis infections should be used cautiously.

Viral Respiratory Tract Infections in Adult Patients Attending Outpatient and Emergency Departments, Taiwan, 2012-2013: A PCR/Electrospray Ionization Mass Spectrometry Study.

AbstractViral etiologies of respiratory tract infections (RTIs) have been less studied in adult than in pediatric populations. Furthermore, the ability of PCR/electrospray ionization mass spectrometry (PCR/ESI-MS) to detect enteroviruses and rhinoviruses in respiratory samples has not been well evaluated. We sought to use PCR/ESI-MS to comprehensively investigate the viral epidemiology of adult RTIs, including testing for rhinoviruses and enteroviruses.Nasopharyngeal or throat swabs from 267 adults with acute RTIs (212 upper RTIs and 55 lower RTIs) who visited a local clinic or the outpatient or emergency departments of a medical center in Taiwan between October 2012 and June 2013 were tested for respiratory viruses by both virus isolation and PCR/ESI-MS. Throat swabs from 15 patients with bacterial infections and 27 individuals without active infections were included as control samples.Respiratory viruses were found in 23.6%, 47.2%, and 47.9% of the 267 cases by virus isolation, PCR/ESI-MS, and both methods, respectively. When both methods were used, the influenza A virus (24.3%) and rhinoviruses (9.4%) were the most frequently identified viruses, whereas human coronaviruses, human metapneumovirus (hMPV), enteroviruses, adenoviruses, respiratory syncytial virus, and parainfluenza viruses were identified in small proportions of cases (<5% of cases for each type of virus). Coinfection was observed in 4.1% of cases. In the control group, only 1 (2.4%) sample tested positive for a respiratory virus by PCR/ESI-MS. Patients who were undergoing steroid treatment, had an active malignancy, or suffered from chronic obstructive pulmonary disease (COPD) were at risk for rhinovirus, hMPV, or parainfluenza infections, respectively. Overall, immunocompromised patients, patients with COPD, and patients receiving dialysis were at risk for noninfluenza respiratory virus infection. Rhinoviruses (12.7%), influenza A virus (10.9%), and parainfluenza viruses (7.3%) were the most common viruses involved in the 55 cases of lower RTIs. The factors of parainfluenza infection, old age, and immunosuppression were independently associated with lower RTIs.In conclusion, PCR/ESI-MS improved the diagnostic yield for viral RTIs. Non-influenza respiratory virus infections were associated with patients with comorbidities and with lower RTIs. Additional studies that delineate the clinical need for including non-influenza respiratory viruses in the diagnostic work-up in these populations are warranted.

Genome Sequence of Aeromonas taiwanensis LMG 24683T, a Clinical Wound Isolate from Taiwan

ABSTRACT Aeromonas taiwanensis was first described in 2010 on the basis of one clinical wound isolate (strain LMG 24683T = A2-50T = CECT 7403T) from Taiwan. We present here the genome sequence of A. taiwanensis LMG 24683T, which carries several genes encoding virulence determinants and Ambler class C and D β-lactamases.

Genome sequences of three Helicobacter pylori strains from patients with gastric mucosa-associated lymphoid tissue lymphoma

ABSTRACT Most of the published complete genome sequences of Helicobacter pylori strains are limited to clinical isolates associated with gastritis, peptic ulcers, or gastric cancer. The genome sequences of three H. pylori strains isolated from patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma are presented here to facilitate studies of H. pylori-associated MALT lymphomagenesis.

Identification of fungal pathogens from clinical specimens using multi-locus PCR coupled with electrospray ionization mass spectrometry.

Polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) was successfully used to identify a variety of fungi, including mixed fungal species, from 10 of 12 clinical specimens (10 culture-negative) of biopsy tissues or body fluids from patients with fungal infections. The application of PCR/ESI-MS for identifying fungal pathogens is discussed.