Prevalence and characterization of enterotoxigenic Bacteroides fragilis and toxigenic Clostridium difficile in a Taipei emergency department.

BACKGROUND/PURPOSE: Enterotoxigenic Bacteroides fragilis (ETBF) and toxin-encoding Clostridium difficile (TXCD) are associated with gastroenteritis. Routine anaerobic blood culture for recovery of these anaerobic pathogens is not used for the detection of their toxins, especially for toxin-variant TXCD. The aim of this study was to investigate the prevalence and risk factors of the genotypes of these anaerobes in patients with acute diarrheal illnesses. METHODS: The data and samples of 513 patients with gastroenteritis were collected in a Taipei emergency department from March 1, 2006 to December 31, 2009. Nonenterotoxigenic B. fragilis (NTBF) and ETBF and the toxin genotypes of TXCD were detected by molecular methods. RESULTS: The prevalence rates of NTBF, ETBF, and TXCD infections were 33.14%, 1.56%, and 2.34%, respectively. ETBF infections often occurred in the elderly (average age = 67.13 years) and during the cold, dry winters. TXCD infections were widely distributed in age and often occurred in the warm, wet springs and summers. The symptoms of ETBF-infected patients were significantly more severe than those of NTBF-infected patients. CONCLUSION: This study identified and analyzed the prevalence, risk factors, and clinical presentations of these anaerobic infections. Future epidemiologic and clinical studies are needed to understand the role of ETBF and TXCD in human gastroenteritis.

Etiology and Risk Factors of Acute Gastroenteritis in a Taipei Emergency Department: Clinical Features for Bacterial Gastroenteritis.

BACKGROUND: The causative pathogen is rarely identified in the emergency department (ED), since the results of cultures are usually unavailable. As a result, antimicrobial treatment may be overused. The aim of our study was to investigate the pathogens, risk factors of acute gastroenteritis, and predictors of acute bacterial gastroenteritis in the ED. METHODS: We conducted a matched case-control study of 627 stool samples and 612 matched pairs. RESULTS: Viruses (41.3%) were the leading cause of gastroenteritis, with noroviruses (32.2%) being the most prevalent, followed by bacteria (26.8%) and Giardia lamblia (12.4%). Taking antacids (adjusted odds ratio [aOR] 4.10; 95% confidence interval [CI], 2.57-6.53), household members/classmates with gastroenteritis (aOR 4.69; 95% CI, 2.76-7.96), attending a banquet (aOR 2.29; 95% CI, 1.64-3.20), dining out (aOR 1.70; 95% CI, 1.13-2.54), and eating raw oysters (aOR 3.10; 95% CI, 1.61-5.94) were highly associated with gastroenteritis. Elders (aOR 1.04; 05% CI, 1.02-1.05), those with CRP >10 mg/L (aOR 2.04; 95% CI, 1.15-3.62), or those who were positive for fecal leukocytes (aOR 2.04; 95% CI, 1.15-3.62) or fecal occult blood (aOR 1.97; 95% CI, 1.03-3.77) were more likely to be hospitalized in ED. In addition, presence of fecal leukocytes (time ratio [TR] 1.22; 95% CI, 1.06-1.41), abdominal pain (TR 1.20; 95% CI, 1.07-1.41), and frequency of vomiting (TR 0.79; 95% CI, 0.64-0.98) were significantly associated with the duration of acute gastroenteritis. Presence of fecal leukocytes (aOR 2.08; 95% CI, 1.42-3.05), winter season (aOR 0.45; 95% CI, 0.28-0.74), frequency of diarrhea (aOR 1.69; 95% CI, 1.01-2.83), and eating shrimp or crab (aOR 1.53; 95% CI, 1.05-2.23) were highly associated with bacterial gastroenteritis. The area under the receiver operating characteristic curve of the final model was 0.68 (95% CI, 0.55-0.63). CONCLUSIONS: Acute bacterial gastroenteritis was highly associated with season, frequency of diarrhea, frequency of vomiting, and eating shrimp or crab.

A norovirus outbreak in a nursing home: norovirus shedding time associated with age.

BACKGROUND: Norovirus (NoV) GII.4 has been identified as predominant in outbreaks in the long-term health-care facilities. OBJECTIVES: NoV excretion during an outbreak of gastroenteritis affecting 19/42 residents and 12/33 employees was investigated in a Taiwan nursing home. STUDY DESIGN: Real-time reverse transcription polymerase chain reaction (RT-PCR) was used to quantify viral RNA from stool samples up to the point of negative detection. RESULTS: Initial fecal viral loads in affected residents were higher than in affected employees (p=0.024). Viral reduced rate was measured as 0.66/day, with a viral half-life of 1.7 days. A mixed model indicated that time (days post-illness onset), initial virus load and resident status (as opposed to employee status) were the most important determining factors of fecal NoV concentration. According to a univariable accelerated failure time (AFT) model, strong associations existed between virus excretion duration and both age (p=0.005) and resident status (p=0.004). No associations were noted between viral excretion duration and either initial viral load or diarrhea duration. According to a multivariable AFT model, age was the only factor affecting virus excretion duration. CONCLUSION: In conclusion, outbreaks in nursing homes may have resulted from environmental contamination, the existence of asymptomatic residents and prolonged virus shedding time in the elderly and care providers. This outbreak finished quickly because frequent cleaning of the surface was done and contact precautions were taken for prolonged viral shedding residents.

An outbreak of varicella among schoolchildren in Taipei.

BACKGROUND: The reported cases with varicella have not decreased and outbreaks of varicella among vaccinated children continue to be reported 9 years after the public vaccination program in Taipei. We investigated an outbreak to determine varicella vaccine coverage and effectiveness. METHODS: An outbreak occurred in an elementary school which located in southern Taipei from April 2007 through May 2007. A retrospect cohort study was performed by using a self-administered questionnaire for parents. RESULTS: Ten out of sixteen varicella cases were vaccinated. Overall vaccine coverage was 71.2%. The common reasons for not receiving varicella vaccine were that varicella vaccine was unavailable because the student didn't live in Taipei (29.4%) or the children could not be vaccinated due to certain illnesses (23.5%). The sensitivity and specificity of self-reported vaccination status was 0.900 (95% CI: 0.864, 0.935) and 0.611 (95% CI: 0.514, 0.701).The vaccine effectiveness was 69.3%-100.0% against any disease severity of varicella. Overall vaccine effectiveness against moderate or severe varicella was 85.5%. Attending cram school was associated with the risk of developing the varicella illness (RR: 13.39; 95% CI: 5.38, 33.31). Unvaccinated students tended to show moderate to severe (>50 lesions) afflictions of the disease (RR: 4.17; 95% CI: 1.15, 15.14). CONCLUSIONS: Because of the low vaccination coverage, varicella outbreaks continue to be reported in Taipei. Increasing vaccine coverage and second dose vaccination for increasing vaccine effectiveness may be considered.

Using the Health Belief Model to understand caregiver factors influencing childhood influenza vaccinations.

OBJECTIVE: This study applied the Health Belief Model to investigate factors in the decision by caregivers to vaccinate their children for influenza. DESIGN: Cross-sectional study. SAMPLE AND MEASUREMENTS: Purposive sampling obtained 2,778 useable responses to surveys of 33 public health centers and 40 medical institutions participating in vaccination programs in southern Taiwan. Data were collected using the Caregiver Demographics and Children's Health History Questionnaire, Children's Influenza Vaccination History Questionnaire, and a Health Belief Model Questionnaire. Multiple logistic regression was used to analyze predictors of influenza vaccinations in children. RESULTS: Predictors of vaccination revealed by logistic regression analysis included age, current employment, and residence of the caregiver as well as chronic disease, hospitalization, and influenza histories of the child. Other predictors revealed by the Health Belief Model were perceived susceptibility of the children to influenza, perceived benefits of vaccinations to children, perceived barriers to vaccinations, and cues to action. Eleven items in the model were also significant predictors of vaccination. CONCLUSIONS: The survey results can be used to develop strategies for increasing influenza vaccination rates.

Evaluation of a new single-tube multiprobe real-time PCR for diagnosis of Entamoeba histolytica and Entamoeba dispar.

A single-tube multiprobe real-time PCR assay for simultaneous detection of Entamoeba histolytica and Entamoeba dispar was developed. One primer pair with 2 species-specific probes was designed based on new SSU RNA regions of the ribosomal DNA-containing episome. The sensitivity is 1 parasite per milliliter of feces and thus superior to the conventional nested PCR and comparable to other published real-time PCR protocols. The applicability for clinical diagnosis was validated with 218 stool specimens from patients. A total of 51 E. histolytica and 39 E. dispar positive samples was detected by the multiprobe real-time PCR compared to 39 and 22 by routine nested PCR diagnosis. The detection rate of Entamoeba species for the multiprobe real-time PCR assays was significantly higher than the nested PCR (40.8% vs. 28.0%, P < 0.01). The test did not show cross reactivity with DNA from Entamoeba moshkovskii, Giardia lamblia , Cryptosporidium sp., Escherichia coli , or other nonpathogenic enteric parasites. The multiprobe real-time PCR assay is simple and rapid and has high specificity and sensitivity. The assay could streamline the laboratory diagnosis procedure and facilitate epidemiological investigation.

Impact of HAART therapy on co-infection of tuberculosis and HIV cases for 9 years in Taiwan.

Free highly active antiretroviral therapy (HAART) was made available by The Department of Health since April 1997. As a result, the incidence rate of tuberculosis (TB)/human immunodeficiency virus (HIV) co-infection among HIV cases rose from 1.90% to 3.82% during 1993 to 1998 and decreased from 3.82% to 0.94% during 1998 to 2006. The incidence rate of TB/HIV co-infection among HIV cases reached its peak in 1998 and then started to reverse, although the next year the TB disease burden (incidence rate: 62.7 cases per 100,000 persons) remained consistently high, and this continued in the following years. The survival rate of TB/HIV co-infection cases was 62.16% during the period 1993-1996 (pre-free HAART era) and increased to 86.60% during the period 1998-2006 (P < 0.0001) (post-free HAART era). Highly active antiretroviral therapy decreased the incidence rate of new TB/HIV co-infection cases among HIV cases and increased the survival rate of TB/HIV co-infection cases.

Unexplained deaths and critical illnesses of suspected infectious cause, Taiwan, 2000-2005.

We report 5 years' surveillance data from the Taiwan Centers for Disease Control on unexplained deaths and critical illnesses suspected of being caused by infection. A total of 130 cases were reported; the incidence rate was 0.12 per 100,000 person-years; and infectious causes were identified for 81 cases (62%).

Prevalence of obesity and its association with cardiovascular disease risk factors in adolescent girls from a college in central Taiwan.

Although obesity is associated with important hemodynamic disturbances, little data exists on population-wide cardiovascular risk factors in obese adolescent girls in Taiwan. This study measured the prevalence of overweight/obesity and related cardiovascular disease risk factors in adolescent females. This was a school-based survey of a representative sample of 291 females aged 15 and 18 years in a public college in Central Taiwan. The main measures were height, body weight, systolic (SBP) and diastolic blood pressure (DBP), uric acid, cholesterol, triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C). Obese (body mass index [BMI] > or = 25.3) and overweight (22.7 < or = BMI < or = 25.2) individuals were combined and labeled as overweight (BMI > or = 22.7) to make communication of results clearer. Data gleaned from freshmens health examinations were analyzed. The prevalence of obesity (BMI > or = 25.3) was 9.28% and of overweight (BMI > or = 22.7) was 21.31%. Being overweight was associated with higher SBP, DBP, uric acid and TG, and lower levels of HDL-C, but was not associated with cholesterol. The 15-year-old group showed higher mean levels of uric acid, total cholesterol, TG and HDL-C than the 18-year-old group (p < 0.05). All told, 3.1%, 15.12% and 2.1% of the girls showed abnormally elevated levels of uric acid, cholesterol and TG, respectively. In addition, 5.84% had abnormally lower HDL-C levels, indicating that interventions should focus on reducing obesity and encouraging proper dietary habits and sufficient exercise, especially in subjects with lower HDL-C levels and higher levels of cholesterol, TG and uric acid.

Survey of the status of self-paid varicella vaccination among children one to six years of age in Taiwan.

BACKGROUND AND PURPOSE: Prior to 2004, the mass immunization program in Taiwan did not include varicella vaccine; however, parents could have their children vaccinated by the self-payment option. METHODS: In April 2002, we distributed 1271 questionnaires to the caregivers of children aged 1 to 6 years in Taoyuan county, Taiwan, to survey the status of vaccination rate against varicella, parental attitudes toward self-paid varicella vaccine, and the demographic characteristics of the family. RESULTS: Based on the answers provided in the questionnaires (99% response rate), we learned that until April 2002, the vaccination rate against varicella was 26%. Most children received this vaccine by the age of 1 to 2 years (64%) mainly at local clinics (66%). Majority of the caregivers (94%) would have immunized their children against varicella if the vaccines were freely provided or partially paid for. Caregivers living in the city, those children whose parents had a relatively high education level, those from families with fewer children, those whose children were inoculated with other self-paid vaccines, and those parents with a higher family income were significantly (p<0.0001) willing to have their children inoculated. CONCLUSIONS: In Taiwan, most caregivers were willing to have their children immunized against varicella if the vaccines were freely provided, or even if they were partially paid for. In case of other effective vaccines of high cost and not included in mass immunization, partially paying for the vaccine may be an option, since the parents' willingness was substantially greater when the cost is lowered.

Outbreak of severe acute respiratory syndrome in southern Taiwan, 2003.

This study describes the epidemiologic features of the severe acute respiratory syndrome (SARS) outbreak in southern Taiwan in 2003. According to the official files of reported cases of SARS from February 21 to June 19, 2003, there were 586 cases in southern Taiwan. Symptom onset occurred between February 21 and June 19 in reported cases, between March 13 and May 30 in probable cases, and between March 17 and May 23 in polymerase chain reaction (PCR)-positive probable cases. Dates of symptom onset were earliest for six imported cases, followed by 53 cases related to nosocomial infections and 51 cases without known sources of infection. The positive rates of the PCR for these three groups decreased from 50.0% to 28.3% to 3.9% , respectively (P < 0.001, by chi-square test for linear trend). Three other cases resulted from exposure to contaminated hospitals in northern Taiwan, one of which was the index case of the nosocomial infection. Imported cases following nosocomial infection were the major cause of SARS infections in southern Taiwan. Due to the low positive rate of the PCR for SARS coronavirus, and the low positive predictive value of reported cases, the factuality of cases with unknown sources of infection should be further verified.

Transmission of the severe acute respiratory syndrome on aircraft.

BACKGROUND: The severe acute respiratory syndrome (SARS) spread rapidly around the world, largely because persons infected with the SARS-associated coronavirus (SARS-CoV) traveled on aircraft to distant cities. Although many infected persons traveled on commercial aircraft, the risk, if any, of in-flight transmission is unknown. METHODS: We attempted to interview passengers and crew members at least 10 days after they had taken one of three flights that transported a patient or patients with SARS. All index patients met the criteria of the World Health Organization for a probable case of SARS, and index or secondary cases were confirmed to be positive for SARS-CoV on reverse-transcriptase polymerase chain reaction or serologic testing. RESULTS: After one flight carrying a symptomatic person and 119 other persons, laboratory-confirmed SARS developed in 16 persons, 2 others were given diagnoses of probable SARS, and 4 were reported to have SARS but could not be interviewed. Among the 22 persons with illness, the mean time from the flight to the onset of symptoms was four days (range, two to eight), and there were no recognized exposures to patients with SARS before or after the flight. Illness in passengers was related to the physical proximity to the index patient, with illness reported in 8 of the 23 persons who were seated in the three rows in front of the index patient, as compared with 10 of the 88 persons who were seated elsewhere (relative risk, 3.1; 95 percent confidence interval, 1.4 to 6.9). In contrast, another flight carrying four symptomatic persons resulted in transmission to at most one other person, and no illness was documented in passengers on the flight that carried a person who had presymptomatic SARS. CONCLUSIONS: Transmission of SARS may occur on an aircraft when infected persons fly during the symptomatic phase of illness. Measures to reduce the risk of transmission are warranted.