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.

Haemophilus influenzae strains possess variations in the global transcriptional profile in response to oxygen levels and this influences sensitivity to environmental stresses.

An alcohol dehydrogenase, AdhC, is required for Haemophilus influenzae Rd KW20 growth with high oxygen. AdhC protects against both exogenous and metabolically generated, endogenous reactive aldehydes. However, adhC in the strain 86-028NP is a pseudogene. Unlike the Rd KW20 adhC mutant, 86-028NP does grow with high oxygen. This suggests the differences between Rd KW20 and 86-028NP include broader pathways, such as for the maintenance of redox and metabolism that avoids the toxicity related to oxygen. We hypothesized that these differences affect their resistance to relevant toxic chemicals, including reactive aldehydes. Across a range of oxygen concentrations, despite the growth profiles of Rd KW20 and 86-028NP being similar, there was a significant variation in their sensitivity to reactive aldehydes. 86-028NP is more sensitive to methylglyoxal, formaldehyde and glycolaldehyde under high oxygen than low oxygen as well as compared to Rd KW20. Also, as oxygen levels changed the whole genome gene expression profiles of Rd KW20 and 86-028NP revealed distinctions in their transcriptomes (the iron, FNR and ArcAB regulons). These were indicative of a difference in their intracellular redox properties and we show it is this that underpins their survival against reactive aldehydes.

A discrete role for FNR in the transcriptional response to moderate changes in oxygen by Haemophilus influenzae Rd KW20.

The survival by pathogenic bacteria within the specific conditions of an anatomical niche is critical for their persistence. These conditions include the combination of toxic chemicals, such as reactive oxygen (ROS) and reactive nitrogen species (RNS), with factors relevant to cell growth, such as oxygen. Haemophilus influenzae senses oxygen levels largely through the redox state of the intracellular fumarate-nitrate global regulator (FNR). H. influenzae certainly encounters oxygen levels that fluctuate, but in reality, these would rarely reach a state that results in FNR being fully reduced or oxidized. We were therefore interested in the response of H. influenzae to ROS and RNS at moderately high or low oxygen levels and the corresponding role of FNR. At these levels of oxygen, even though the growth rate of an H. influenzae fnr mutant was similar to wild type, its ROS and RNS tolerance was significantly different. Additionally, the subtle changes in oxygen did alter the whole cell transcriptional profile and this was different between the wild type and fnr mutant strains. It was the changed whole cell profile that impacted on ROS/RNS defence, but surprisingly, the FNR-regulated, anaerobic nitrite reductase (NrfA) continued to be expressed and had a role in this phenotype.

A new insight into the role of intracellular nickel levels for the stress response, surface properties and twitching motility by Haemophilus influenzae.

Nickel acts as a co-factor for a small number of enzymes in bacteria. Urease is one of the two nickel-dependent enzymes that have been identified in Haemophilus influenzae; glyoxalase I is the other. However, nickel has been suggested to have roles in H. influenzae that can not attributed to the function of these enzymes. We have previously shown that in the H. influenzae strain Rd KW20 the inability to acquire nickel led to alterations to the cell-type; an increased biofilm formation and changes in cell surface properties. Here we report the differences in the genome wide gene expression between Rd KW20 and a strain incapable of importing nickel (nikQ); revealing a link between intracellular nickel levels and genes involved in metabolic pathways, stress responses and genes associated with surface factors such as type IV pili. We have then taken a strain previously shown to use type IV pili both in biofilm formation and for twitching motility (86-028NP) and have shown its homologous genes (NTHI1417-1422; annotated as cobalt transporter, cbiKLMOQ) did import nickel and mutations in this locus had pleiotropic effects correlating to stress response and motility. Compared to wild type cells, the nickel depleted cells were more electronegativity charged, they aggregated and formed a biofilm. Correct intracellular nickel levels were also important for resistance to oxidative stress; the nickel depleted cells were more sensitive to oxidative stress. The nickel depleted cells were also non-motile, but the addition specifically of nickel returned these cells to a wild type motility state. We have also analysed the role of nickel uptake in a naturally, urease negative strain (the blood isolate R2866) and depleting intracellular nickel (a nikQ mutant) in this strain effected a similar range of cell functions. These data reveal a role for the capacity to acquire nickel from the environment and for the correct intracellular nickel levels as part of H. influenzae stress response and in signalling for a switch to a sessile bacterial lifestyle.

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.

A glutathione-based system for defense against carbonyl stress in Haemophilus influenzae.

BACKGROUND: adhC from Haemophilus influenzae encodes a glutathione-dependent alcohol dehydrogenase that has previously been shown to be required for protection against killing by S-nitrosoglutathione (GSNO). This group of enzymes is known in other systems to be able to utilize substrates that form adducts with glutathione, such as aldehydes. RESULTS: Here, we show that expression of adhC is maximally induced under conditions of high oxygen tension as well as specifically with glucose as a carbon source. adhC could also be induced in response to formaldehyde but not GSNO. An adhC mutant was more susceptible than wild-type Haemophilus influenzae Rd KW20 to killing by various short chain aliphatic aldehydes, all of which can be generated endogenously during cell metabolism but are also produced by the host as part of the innate immune response. CONCLUSIONS: These results indicate that AdhC plays a role in defense against endogenously generated reactive carbonyl electrophiles in Haemophilus influenzae and may also play a role in defense against the host innate immune system.

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.

Human trichinosis after consumption of soft-shelled turtles, Taiwan.

In 2008, an outbreak of human trichinosis associated with ingestion of raw soft-shelled turtles was identified and investigated in Taiwan. The data suggested that patients were likely infected with Trichinella papuae.

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.

Effect of free treatment and surveillance on HIV-infected persons who have tuberculosis, Taiwan, 1993-2006.

In 1997, Taiwan made highly active antiretroviral therapy (HAART) available without cost to HIV-infected persons; in 2001, a national web-based surveillance system was implemented. Healthcare workers use the system to monitor patients' conditions and can intervene when necessary. Free HAART, coupled with the surveillance system, appears to have increased survival rates of HIV-infected persons with tuberculosis in Taiwan.

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.

Glutathione-dependent alcohol dehydrogenase AdhC is required for defense against nitrosative stress in Haemophilus influenzae.

In Haemophilus influenzae Rd KW20, we identified a gene, adhC, which encodes a class III alcohol dehydrogenase (AdhC) and has S-nitrosoglutathione reductase activity. adhC exists on an operon with estD, which encodes an esterase. Divergent to the adhC-estD operon is the Haemophilus influenzae nmlR gene (nmlR(HI)), which encodes a MerR family regulator that is homologous to the Neisseria MerR-like regulator (NmlR). Analysis of an nmlR(HI) mutant indicated that expression of the adhC-estD operon is regulated by NmlR(HI) in strain Rd KW20. Chromosomal inactivation of either adhC or nmlR(HI) resulted in sensitivity to S-nitrosoglutathione and decreased S-nitrosoglutathione reductase activity. Examination of the NmlR(HI)-AdhC system in the genome sequences of nontypeable H. influenzae strains R2846, R2866, and 86-028NP identified significant variations. The adhC gene of 86-028NP was predicted to be nonfunctional due to a premature stop codon. Polymorphisms in the operator/promoter region of R2866 resulted in reduced enzyme activity. This correlated with an increased sensitivity to S-nitrosoglutathione. The adhC-nmlR(HI) system was examined in thirty-three clinical isolates (both capsular and nontypeable strains). Nucleic acid sequence data showed that only strain 86-028NP contained a premature stop codon. There were some variations in the DNA sequence of the operator/promoter region which altered the nmlR(HI) promoter. However, the clinical isolates still possessed S-nitrosoglutathione reductase activity and showed at least the equivalent ability to grow in the presence of S-nitrosoglutathione as Rd KW20. These data suggest that the nmlR(HI)-adhC system has a role in the defense against nitrosative stress in Haemophilus influenzae.

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.

Prognostic factors of organophosphate poisoning between the death and survival groups.

In this prospective case series study, we consider the different factors between death and survival groups of organophosphate poisoning. Patients in tertiary-care medical center who had been exposed to organophosphate were included in the study. Pralidoxime (PAM) was discontinued after atropine had controlled the clinical situation. We recorded the demographic data, amount of organophosphate consumption, duration of coma, duration of ventilator use, duration of hospitalization, findings of chest X-ray, white blood cell count, acetylcholinesterase concentration, plasma cholinesterase concentration, total atropine amount, duration of atropine use, total PAM amount, duration of PAM use, urine organophosphate peak concentration, duration of urine organophosphate and mortality rate. Urine was collected every 8 hours and was analyzed by gas chromatography equipped with a flame photometric detector and gas chromatography with mass spectrometer detector for organophosphate determination. The urine organophosphate peak concentration was recorded. Wilcoxon rank sum test was used to compare the factors between death and survival groups. Fisher's exact test was used to compare the different findings of chest X-ray between the death and survival groups. Evidently, the death group had a higher amount of organophosphate consumption, duration of coma, and higher white blood cell count than those in the survival group. Also, the death group had lower duration of hospitalization, and decreased concentrations of acetylcholinesterase and plasma cholinesterase. Total PAM amount use and duration of PAM use were lower. However, the duration of ventilator use, findings of chest X-ray, total atropine amount, duration of atropine, urine organophosphate peak concentration and duration of urine organophosphate were similar in both groups. The mortality rate of our 50 cases was 20%. As stated earlier, the cases of the death group had insufficient PAM therapy. The maximum duration of PAM use was shorter than the maximum duration of urine organophosphate, although the medians of duration of PAM use were more than the medians of duration of urine organophosphate in both the survival and death groups. Prolonged coma duration, lower level of acetylcholinesterase and lower level of plasma cholinesterase were related to the poor prognosis of the patients.

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.