Tzou Yien Lin

Clinical and epidemiologic features of Coxsackievirus A6 infection in children in northern Taiwan between 2004 and 2009

BACKGROUND Isolates of Coxsackievirus A6 (Cox A6) is increasing clinically in 2009 in Taiwan but detailed clinical features of Cox A6 infections in children have not been reported. This study is to define clinical manifestations and laboratory findings of Cox A6 infection in children. METHODS From January 2004 to December 2009, a total of 4,664 children with enterovirus infections, based on throat virus culture, were treated in Chang Gung Childrens hospital. Two hundred and ninety-six (6.3%) patients positive for Cox A6 infection were included in this study. One hundred and forty-one (47.6%) inpatients were further analyzed for clinical presentations, laboratory findings, and clinical diagnoses. RESULTS There were two peaks of Cox A6 infection in 2007 and 2009 during the study period, especially during the warm season. The proportion of Cox A6 among total enterovirus isolates was 15.5% in 2007 and up to 22.2% in 2009. The mean age of inpatients was 2.42 ± 0.14 years. The mean hospitalization duration was 4.21 ± 0.11 days. The most common symptoms were fever (100%), oral ulcers (90.8%), and decreased oral intake (89.4%). The mean duration of fever was 2.78 ± 1 days (range, 1-7 days). Seventy-seven (54.6%) patients had fever more than 3 days. The mean leukocyte count was 14,850/mm(3), and 63 (45%) patients had leukocytosis (>15,000/mm(3)). The mean serum C-reactive protein (CRP) level was 44.1 ± 3.3 mg/L (normal, <10 mg/L) and 62 (44%) had a CRP level >40 mg/L. One hundred and eight (76.6%) inpatients were diagnosed as herpangina and 18 (12.8%) hand-foot-mouth disease. Three patients had complications, including aseptic meningitis in one and encephalitis in two. All 141 inpatients recovered uneventfully. CONCLUSIONS Cox A6 is among the major serotypes of enteroviruses in Taiwan and most cases presented as herpangina and hand-foot-mouth disease. Nearly half of the cases may have leukocytosis and elevated CRP levels. Outcomes are usually good.

Factors Associated with Nasal Colonization of Methicillin-Resistant Staphylococcus aureus among Healthy Children in Taiwan

ABSTRACT Methicillin-resistant Staphylococcus aureus (MRSA) has been identified as a major cause of community-associated (CA) S. aureus infections in the past decade. The main reservoir in the community for MRSA and the factors contributing to its worldwide spread remain poorly defined. Between July 2005 and June 2008, a total of 6,057 healthy children 2 to 60 months of age were screened for carriage of S. aureus and Streptococcus pneumoniae in Taiwan. The prevalence and epidemiological factors influencing MRSA carriage were determined. MRSA strains were tested for antimicrobial susceptibility and underwent molecular characterization. The overall prevalences of MRSA and S. aureus carriage were 7.8% and 23.2%, respectively. A majority (88%) of MRSA isolates belonged to a common Asian-Pacific CA-MRSA lineage, multilocus sequence type 59, and were resistant to multiple non-beta-lactam antibiotics. The carriage rate of MRSA was higher among subjects 2 to 6 months old (P < 0.0001), residing in northern Taiwan (P = 0.0003), and enrolled later in the study (P < 0.0001). MRSA colonization was associated with the number of children in the family (adjusted odds ratio [aOR], 1.114; 95% confidence interval [CI], 1.002 to 1.240; P = 0.0463) and day care attendance (aOR, 1.530; 95% CI, 1.201 to 1.949; P = 0.0006). Breast feeding (P < 0.0001) and colonization with S. pneumoniae (P = 0.0170) were protective against MRSA colonization. We concluded that epidemic CA-MRSA strains increasingly colonized Taiwanese children between 2005 and 2008. The carriage rate varied significantly across different demographical features. Crowding was an independent environmental risk factor that might accelerate CA-MRSA transmission in the community.

Increased Seroprevalence of HBV DNA With Mutations in the S Gene Among Individuals Greater Than 18 Years Old After Complete Vaccination

BACKGROUND & AIMS Despite the success of a universal vaccination program against hepatitis B virus (HBV) in Taiwan, a small but substantial proportion of individuals remain infected by mutant viruses that escape the vaccine. We investigated the seroepidemiology and genotypic characteristic of HBV for long periods after neonatal vaccination. METHODS We measured hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), and antibody to hepatitis B surface antigen (anti-HBs) in 1214 serum samples collected throughout Taiwan from individuals 0.6-87.8 years old in 2007. HBV DNA was detected using polymerase chain reaction and sequence analysis in vaccine recipients who tested positive for anti-HBc and/or HBsAg. RESULTS The overall seroprevalence of HBsAg and anti-HBc was significantly lower among individuals born after the initiation of the nationwide vaccination program (P < .001). However, we observed increasing seroprevalence of anti-HBc and isolated anti-HBs when subjects were grouped by age: at 10-14, 14-18, to 18-21 years of age, values were 0.4%, 1.9%, and 8.1% (P = .0135) and 43.7%, 55.4%, and 59.6% (P = .0093), respectively (χ(2) test for trend). A large increase was observed in the percentage of patients who tested positive for HBV DNA at 18-21 years of age (3.0% vs 0.2% [P = .002] for all eligible subjects and 5.7% vs 0.3% [P < .001] for subjects vaccinated with ≥3 doses). Five of 8 completely vaccinated individuals who were seropositive for HBV DNA carried variants with mutations in the S gene. CONCLUSIONS Universal vaccination effectively controls HBV infection in children and adolescents. However, after adolescence, there is a significant increase in the seroprevalence of anti-HBs, anti-HBc, and HBV DNA, indicating that new preventative strategies are needed for adults.

Cross-reactive Neutralizing Antibody Responses to Enterovirus 71 Infections in Young Children: Implications for Vaccine Development

Background Recently, enterovirus 71 (EV71) has caused life-threatening outbreaks involving neurological and cardiopulmonary complications in Asian children with unknown mechanism. EV71 has one single serotype but can be phylogenetically classified into 3 main genogroups (A, B and C) and 11 genotypes (A, B1∼B5 and C1∼C5). In Taiwan, nationwide EV71 epidemics with different predominant genotypes occurred in 1998 (C2), 2000–2001 (B4), 2004–2005 (C4), and 2008 (B5). In this study, sera were collected to measure cross-reactive neutralizing antibody titers against different genotypes. Methods We collected historical sera from children who developed an EV71 infection in 1998, 2000, 2005, 2008, or 2010 and measured cross-reactive neutralizing antibody titers against all 11 EV71 genotypes. In addition, we aligned and compared the amino acid sequences of P1 proteins of the tested viruses. Results Serology data showed that children infected with genogroups B and C consistently have lower neutralizing antibody titers against genogroup A (>4-fold difference). The sequence comparisons revealed that five amino acid signatures (N143D in VP2; K18R, H116Y, D167E, and S275A in VP1) are specific for genogroup A and may be related to the observed antigenic variations. Conclusions This study documented antigenic variations among different EV71 genogroups and identified potential immunodominant amino acid positions. Enterovirus surveillance and vaccine development should monitor these positions.

Comparative Genomic Analysis of Coxsackievirus A6 Strains of Different Clinical Disease Entities

Background Studies regarding coxsackievirus A6 (CVA6) infection were limited. In Taiwan, outbreaks of CVA6 occurred in 2009 and 2010, respectively, but the clinical manifestations were markedly different. We conducted a study to compare the clinical features and genomic sequence between the two years. Methodology/Principal Findings In 2009 and 2010, 205 patients with coxsackievirus A6 (CVA6) infection were treated at Chang Gung Memorial Hospital. Detailed clinical features were obtained from 126 inpatients, 62 in 2009 and 64 in 2010. Between the inpatients in 2009 and 2010, no statistically significant difference was noted in terms of demographics, length of hospital stay and laboratory data. Significantly more patients in 2009 presented with herpangina (82%) while more patients in 2010 presented with hand-foot-mouth disease (HFMD; 67%) and skin rash beyond the typical sites for HFMD. Complete genomic sequences were determined and compared for three isolates from patients with herpangina in 2009 and three isolates from patients with HFMD in 2010. The complete sequences showed that 2009 and 2010 CVA6 isolates were indistinguishable by partial VP1 genes, but there were 5 unique nucleotide changes in 3′ UTR, and 23 out of 2201 (1%) amino acids were different. 2010 viruses underwent the largest number of amino acid changes in 3CD protein, which is the precursor of both 3C protease and 3D polymerase. Conclusions Since 2008 in Finland, outbreaks of HFMD due to CVA6 were noted internationally. CVA6 of different genetic background may cause different clinical manifestations such as herpangina and HFMD.

Successful Control of Methicillin-Resistant Staphylococcus aureus in Endemic Neonatal Intensive Care Units—A 7-Year Campaign

Background Methicillin-resistant Staphylococcus aureus (MRSA) is among the most important nosocomial pathogens in the intensive care unit (ICU) worldwide, including Taiwan. Since 1997, our neonatal ICUs (NICUs) had become endemic for MRSA. Methodology/Principal Findings To control MRSA spread in our NICUs, we implemented a series of infection control measures stepwise, including reinforcement of hand hygiene since January 2000, augmentation of aseptic care over the insertion site of central venous catheter since July 2001, introduction of alcohol-based handrubs since April 2003, surveillance culture for MRSA and cohort care for the colonized patients between March 2003 and February 2004, and surveillance culture with subsequent decolonization of MRSA between August 2005 and July 2006. After implementation of these measures, MRSA healthcare-associated infection (HAI) density reduced by 92%, from 5.47 episodes per 1000 patient-days in 1999 to 0.45 episodes per 1000 patient-days in 2006; MRSA bloodstream infection reduced from 40 cases in 1999 to only one case in 2006. Compared to those obtained during the period of surveillance culture without decolonization, both rates of MRSA colonization (8.6% vs. 41%, p<0.001) and infection (1.1% vs. 12%, p<0.001) decreased significantly during the period of surveillance and decolonization. Molecular analysis of the clinical isolates during the study period showed that the endemic clone, which dominated between 1998 and 2005, almost disappeared in 2006, while the community clones increased significantly in 2006–2007. Conclusion/Significance Through infection control measures, MRSA HAIs can be successfully controlled, even in areas with high levels of endemic MRSA infections such as our NICUs.

Primary Epstein-Barr Virus Infection Associated with Kikuchi's Disease and Hemophagocytic Lymphohistiocytosis: A Case Report and Review of the Literature

An association between hemophagocytic lymphohistiocytosis (HLH) and Kikuchis disease is rarely seen in children. Here, we present the case of a male adolescent (age 16 years and 3 months) who suffered from spiking fever for more than 1 week, and multiple nodules over the neck and bilateral axilla for 2 months. A skin rash also developed over all four limbs, abdomen and face. Laboratory data and skin biopsy gave results compatible with a diagnosis of Kikuchis disease. Hemophagocytosis in the bone marrow, hyper-triglyceridemia, elevated ferritin, and splenomegaly were also found, fulfilling the criteria for HLH. A recent primary Epstein-Barr virus infection was also diagnosed by serology. The patient ran a relatively benign course. Intravenous immunoglobulins, steroids or etoposide-containing regimens were not used, and his recovery was uneventful. A review of the literature showed that up to February 2009, 11 additional cases of Kikuchis disease presenting simultaneously with, or mimicking, HLH had been reported. Complete resolution within several weeks, with no recurrence, was seen in all but one patient (a pregnant woman).

Viral etiology of bronchiolitis among pediatric inpatients in northern Taiwan with emphasis on newly identified respiratory viruses

Purpose Viral etiology of bronchiolitis in children in Taiwan has been fragmentary. We conducted a prospective study to figure out the viral epidemiology of bronchiolitis in Taiwan. Materials and methods From January 2009 to March 2011, a total of 113 children with bronchiolitis, aged <2 years, hospitalized in Chang Gung Children’s Hospital were randomly selected for viral etiology investigation. Nasopharyngeal aspirates were obtained from each case and sent for viral detection by tissue culture, antigen test, and polymerase chain reaction. Results A total of 120 viruses were detected from 113 children. Positive viral etiology was identified in 86 (76%) children. Mixed viral pathogens were found in 28 cases (25%). Respiratory syncytial virus (RSV) was the most common pathogen and was identified in 43.4% of the cases. Human bocavirus (hBoV) was the second most common identified virus (in 19.5%), followed by human metapneumovirus (hMPV), rhinovirus, influenza viruses, and coronavirus OC43. In terms of clinical characteristics, no significant difference was found among the children with bronchiolitis either caused by different single or mixed viral infection. Conclusion RSV was the most common etiologic agent for children with bronchiolitis in Taiwan. Newly identified viruses, including hMPV and hBoV, were also among the common causative agents. Clinical characteristics were not significantly different among the children with bronchiolitis caused by different viruses.

Clinical features of coxsackievirus A4, B3 and B4 infections in children.

Background Clinical features of coxsackievirus A4 (CA4), B3 (CB3) and B4 (CB4) infections in children have not been comprehensively described. Methods/Principal Findings From January 2004 to June 2012, a total of 386 children with culture-proven CA4, CB3 and CB4 infections treated at Chang Gung Memorial Hospital, including 296 inpatients (CA4, 103; CB3, 131; CB4, 62) and 90 outpatients (CA4, 55; CB3, 14; CB4, 21), were included. From outpatients, only demographics were extracted and from inpatients, detailed clinical and laboratory data were collected retrospectively. The mean age was 32.1±30.2 months; male to female ratio was 1.3∶1. Children with CB3 infection were youngest (76.6% <3 years of age), and had a highest hospitalization rate (90.3%) and a longest duration of hospitalization (mean ± SD, 7.5±6.2 days). Herpangina (74.8%) was the most common presentation for children with CA4 infection, aseptic meningitis (26.7%) and young infant with fever (23.7%) for those with CB3 infection, and herpangina (32.3%) and tonsillitis/pharyngitis (27.4%) for children with CB4 infection. Almost all the inpatients had fever (97.6%). Twelve out of thirteen (92.3%) children with complications and ten of 11 children with long-term sequelae had CB3 infections. Two fatal cases were noted, one due to myocarditis with CA4 infection and CB3 were detected from the other case which had hepatic necrosis with coagulopathy. The remaining 285 children (96.3%) recovered uneventfully. Conclusion CA4, CB3 and CB4 infections in children had different clinical disease spectrums and involved different age groups. Though rare, severe diseases may occur, particularly caused by CB3.

Clinical features of radiologically confirmed pneumonia due to adenovirus in children

BACKGROUND Clinical features of radiologically confirmed pneumonia due to adenovirus in children have not been comprehensively evaluated. OBJECTIVE To describe the detailed clinical features of radiologically confirmed adenovirus-associated pneumonia in children. STUDY DESIGN Of 3298 children with a throat virus culture positive for adenovirus treated at a university-affiliated hospital, from January 2000 to June 2008, in northern Taiwan, 80 hospitalized children (2.4%) with radiologically confirmed pneumonia were identified. From four children with incomplete medical records, only demographics were included for analysis. RESULTS The median age was 2.97 years, ranging from 25 days to 14 years. Seventy-three patients (96%) had fever, with a median duration of 7 days. The three most common respiratory symptoms were cough (99%), rhinorrhea (82%) and dyspnea (42%). Gastrointestinal symptoms were recorded in 80% of the patients, and neurologic symptoms in four children. Leukocytosis (WBC≥15,000/μL) was noted in 19 (25%) patients. Only six patients (8%) had a normal serum C-reactive protein (CRP) value (<5 mg/L), while 48 patients (63%) had a CRP level >40 mg/L. Seventeen (21%) children required intensive care. Seventy-three patients (96%) recovered uneventfully. Sequelae were seen in two patients and death in 1. Of the 69 isolates with serotyping determination, seven serotypes were identified, with a predominant serotype (type 3 for 73%). CONCLUSION Less than 5% of the children with adenoviral infection had radiologically confirmed patch pneumonia. The manifestation of pneumonia caused by adenovirus was similar to that of bacterial pneumonia.