Genming Zhao

Serotype distribution and antimicrobial resistance patterns in Streptococcus pneumoniae isolates from hospitalized pediatric patients with respiratory infections in Shanghai, China.

Background. Surveillance for pneumococcal respiratory illness was conducted in children hospitalized at Affiliated Pediatric Hospital of Fudan University in Shanghai from August 2000 to August 2001. Methods. Sputum cultures were obtained from pediatric patients admitted with pneumonia or respiratory distress by tracheal aspirate. Blood cultures were also performed on a subset of patients. All pneumococcal isolates were serotyped and tested for antibiotic susceptibility. In addition clinical information on the patients including prior antibiotic history was abstracted. Streptococcus pneumoniae tracheal isolations were attempted in a total of 1013 pediatric patients hospitalized during this period. Among these samples 112 specimens were S. pneumoniae-positive. These positive isolates underwent serotyping and antibiotic susceptibility testing. Results. Five serotypes (19F, 23F, 6A, 14, 6B) of S. pneumonia accounted for 81% (91 of 112 cases). Other serotypes accounted only for 12% (13 of 112 cases), and 7% (8 of 112 cases) of isolates could not be typed by quelling test. Only one blood culture isolate was positive, probably reflecting the frequent use of antibiotic treatment before hospitalization. Fifty-one and 8.0% of isolates had intermediate and high level penicillin resistance, respectively. Fifty-eight percent were resistant to ampicillin, 6.6% to cefazolin, 25.0% to cefaclor, 6.6% to ceftriaxone, 85.7% to erythromycin, 66.7% to clindamycin and 28.2% to chloramphenicol. Among 66 isolates that were not susceptible to penicillin, serotype 19F was the most common, followed by 23F and 14. Conclusion. S. pneumoniae is a common cause of respiratory illness requiring hospitalization in young children in Shanghai, with antibiotic resistance increasingly common. Five serotypes account for most disease.

Identifying high-risk regions for schistosomiasis in Guichi, China: A spatial analysis

Schistosomiasis epidemic is reemerging in some areas of China. The extensive snail habitat is a major challenge for a sustainable schistosomiasis control. Direct surveillance on snails for the disease control is no longer a desirable disease control approach due to current low density of infected snails and reduced funding. In this study the benefit of indirect monitoring of acute schistosomiasis cases, using spatial methods including disease mapping and spatial clustering analysis was explored in Guichi, China. Significant global clustering existed for acute cases and two statistically significant spatial clusters were detected, and subsequently validated by field surveys. Our study indicates that the application of geographic information system (GIS) and spatial methods are useful in the epidemiologic surveillance and risk assessment for acute schistosomiasis, providing an alternative approach with minimal funds required.

A longitudinal study of comparison of the Kato-Katz technique and indirect hemagglutination assay (IHA) for the detection of schistosomiasis japonica in China, 2001-2006.

From 2001 to 2006, about one-third of the residents aged 5-65 years were selected as the subjects in a schistosome-endemic village located in Jiangxi Province, China. Every 1 year, all participants were analyzed by the Kato-Katz parasitologic examination and indirect hemagglutination assay (IHA). Statistical analysis of the results showed the k indices ranged from 0.250 to 0.347 between the two methods. Assuming the Kato-Katz results as the gold standard reference, the specificity of the IHA was from 60% to 77%, the positive predictive value of this method was from 19% to 30%, and its sensitivity and negative predictive value were more than 97%. The IHA method is unsuitable for individual screening in endemic community with relatively high prevalence (e.g. with >10% or more prevalence). A search for a better diagnostic test that can be applied in field situations in China is essential and should be given high priority.

Molecular Characterization and Antimicrobial Susceptibility of Streptococcus pneumoniae Isolated from Children Hospitalized with Respiratory Infections in Suzhou, China

Background Dissemination of antibiotic resistant clones is recognized as an important factor in the emergence and prevalence of resistance in pneumococcus. This study was undertaken to survey the antimicrobial susceptibility and serotypes distribution of pneumococci and to explore the circulating clones in hospitalized children in Suzhou, China. Methods The pneumococci were isolated from the nasopharyngeal aspirates of children less than 5 years of age admitted to Soochow-University-Affiliated-Childrens-Hospital with respiratory infections. The capsular serotypes were identified by multiplex polymerase chain reaction (PCR). Antimicrobial susceptibility was tested by E-test. The presence of ermB, mefA/E genes were detected by PCR and the genotypes were explored by Multilocus sequence typing (MLST). Results From July 2012 to July 2013, a total of 175 pneumococcal isolates were collected and all strains were resistant to erythromycin and clindamycin, about 39.4% strains were non-susceptible to penicillin G. Overall, 174 (99.4%) isolates were resistant to ≥3 types of antibiotics. Serotypes 19F (28.1%), 6B (19.7%), 19A (18.0%), and 23F (17.4%) were the most common serotypes in all identified strains. The serotypes coverage of PCV7 and PCV13 were 71.9% and 89.9%, respectively. Four international antibiotic-resistant clones, including Taiwan19F-14 (n = 79), Spain23F-1(n = 25), Taiwan23F-15(n = 7) and Spain6B-2(n = 7), were identified. The Taiwan19F-14 clones have a higher non-susceptibility rate in β-lactams than other clones and non-clone isolates (p<0.001). In addition, 98.7% Taiwan19F-14 clones were positive of both ermB and mefA/E genes, compare to 33.3% in other clones and non-clone strains. Conclusions The spread of international antibiotic-resistant clones, especially Taiwan19F-14 clones, played a predominant role in the dissemination of antimicrobial resistant isolates in Suzhou, China. Considering the high prevalence of PCV7 serotypes and serotype 19A, the introduction of PCV13 may be a promising preventive strategy to control the increasing trend of clonal spread in China.

An Integrated Strategy for Transmission Control of Schistosoma japonicum in a Marshland Area of China: Findings from a Five-Year Longitudinal Survey and Mathematical Modeling

In 2004 an aggressive plan was instituted aiming to achieve nationwide transmission control of schistosomiasis by 2015. Here, we report a longitudinal study on the control of schistosomiasis in Anhui province, China. Using a mathematical model, we compared the effects of different control strategies implemented in the study area. During the 5-year study period, a 60.8% reduction in human prevalence was observed from 2005 (7.95%) to 2009 (3.1%), and snail infection decreased from 0.063% in 2005 to zero in 2009. Results of the model agree well with the first 3-year field observations and suggest continuous decrease in human infections in the last 2 years, whereas the last 2-year field observations indicated that human infections appeared to be stable even with continuous control. Our findings showed that the integrated control strategy was effective, and we speculated that other factors besides bovines might contribute to the local transmission of the disease.

A model for the prediction of Oncomelania hupensis in the lake and marshland regions, China

A model has been developed for predicting the density of Oncomelania hupensis, the intermediate host snail of Schistosoma japonicum. The model takes into account different environmental factors, including elevation, air and soil temperature, type of vegetation, mean height of preponderant vegetation and soil humidity. Deviance and Akaike information criteria were used to determine the best model fits. Model diagnostics and internal and external validations of model efficiency were also performed. From the final prediction model, two important results emerge. First, air temperature should be used with care to study the distribution of O. hupensis and to predict its potential survival because the impact is indirect, and it is weaker and more unstable than soil temperature. Second, the more important environmental factor for O. hupensis prediction at the microscale is soil humidity, but the more important macroscale environmental factor is soil temperature. This finding might help in selecting different environmental features for studying O. hupensis at different spatial scales. Our model is promising for predicting the density of O. hupensis, and hence can provide more objective information about snail dispersal, which might eventually replace the tedious and imprecise field work for annual surveillance of O. hupensis.

Nonparametric spatial analysis to detect high-risk regions for schistosomiasis in Guichi, China.

Schistosomiasis control in China is facing a new challenge due to the rebound of epidemics in many areas and the unsustainable effects of the chemotherapy-based control strategy. Identifying high-risk regions for schistosomiasis is an important first step for an effective and sustainable strategy. Direct surveillance of snail habitats to detect high-risk regions is costly and no longer a desirable approach, while indirect monitoring of acute schistosomiasis may be a satisfactory alternative. To identify high-risk regions for schistosomiasis, we jointly used multiplicative and additive models with the kernel smoothing technique as the main approach to estimate the relative risk (RR) and excess risk (ER) surfaces by analyzing surveillance data for acute schistosomiasis. The feasibility of detecting high-risk regions for schistosomiasis through nonparametric spatial analysis was explored and confirmed in this study, and two significant high-risk regions were identified. The results provide useful hints for improving the national surveillance network for acute schistosomiasis and possible approaches to utilizing surveillance data more efficiently. In addition, the commonly used epidemiological indices, RR and ER, are examined and emphasized from the spatial point of view, which will be helpful for exploring many other epidemiological indices.

Dietary Fiber Intake Is Associated with HbA1c Level among Prevalent Patients with Type 2 Diabetes in Pudong New Area of Shanghai, China

Background Dietary factors play an important role in glycemic control in diabetic patients. However, little is known about their effects among Chinese diabetic patients, whose diets are typically abundant in fiber and high in glycemic index (GI) values. Methodology/Principal Findings 934 patients with type 2 diabetes and 918 healthy volunteers from Pudong New Area, Shanghai, China, were interviewed during the period of Oct-Dec, 2006 to elicit demographic characteristics and lifestyle factors. Dietary habits were assessed using a validated food frequency questionnaire. Anthropometric measurements, bio-specimen collection and biochemical assays were conducted at the interview according to a standard protocol. In this population, diabetic patients consumed lower levels of energy and macronutrients but had higher levels of fasting plasma glucose (FPG), glycolated hemoglobin A1c (HbA1c), triglyceride and body mass index than healthy adults. While the average consumption levels of the nutrients among diabetic patients did not vary along duration of the disease, the average levels of FPG and HbA1c increased with increasing duration. Regardless of diabetes duration, HbA1c level was observed lower in patients having a higher fiber or lower GI intake. Compared with those with the lowest tertile intake of fiber, the adjusted odds ratios (ORs) for poor glycemic control reduced from 0.75 (95%CI: 0.54–1.06) to 0.51 (95%CI: 0.34–0.75) with increasing tertile intake (P for trend <0.001). Conclusions Dietary fiber may play an important role in reducing HbA1c level. Increasing fiber intake may be an effective approach to improve glycemic control among Chinese diabetic patients.

Effects of the praziquantel-based control of schistosomiasis japonica in China

Abstract In 2000–2002, the effects of the praziquantel-based control of Schistosoma japonicum (in which each subject found infected in the October of each year is given a single dose of the drug) were examined at 20 or 21 surveillance sites across China. The pre- and post-treatment prevalences and intensities of infection were compared at each site and after pooling using a random-effects method. One year after treatment, in the communities that had the higher prevalences of infection (> 10%) before treatment, the mean prevalence of infection was found to have fallen by 20.15% [95% confidence interval (CI)=6.95%–31.48%] and the geometric mean intensities of infection (measured as eggs/g faeces) in the currently infected individuals and the entire study cohort were found to have fallen, by 22.91% (CI=14.69%–30.34%) and 33.93% (CI=11.69%–50.68%), respectively (P<0.05 for each). In the communities that had lower prevalences of infection pre-treatment, however, no statistically significant reductions in the intensity of infection were observed, although the prevalences in the communities that had pre-treatment prevalences of 6%–10% did fall significantly post-treatment, by a mean of 24.50% (CI=5.35%–39.83%; P<0.05). These observations indicate that the current annual surveys for infection, in which those found infected are each given a single dose of praziquantel, should help keep the prevalence of human infection with S. japonicum low in China, although chemotherapy alone is unlikely to eradicate the parasite.

Oncomelania hupensis (Gastropoda: Rissooidea), Intermediate Host Of Schistosoma japonicum In China: Genetics and Molecular Phylogeny Based On Amplified Fragment Length Polymorphisms

Schistosomiasis japonica is one of the most serious parasitic diseases in China. Subspecies of the pomatiopsid snail species Oncomelania hupensis transmit the human blood fluke Schistosoma japonicum, the parasite causing the disease. In at least one study involving the subspecies Oncomelania hupensis robertsoni, there was no clear phylogenetic concordance between the mitochondrial and nuclear data, and it was strongly recommended that future studies incorporate more data from nuclear loci in order to better understand phylogeography and host-parasite coevolution (Wilke et al., 2006). In this paper, we explore genetic diversity based AFLP data involving 25 populations throughout mainland China. AFLP is a DNA fingerprinting technique that detects the polymorphism of the whole genome without prior knowledge of the nucleotide sequence, with the high degree of reproducibility and small amount of template DNA needed. Our AFLP data show that: (1) the genetic diversity within an O. hupensis population increases gradually with snail sample size, and when the sample size is more than 30 individuals, the genetic variation within one O. hupensis population trends to stabilization. (2) There is high intra-population genetic variation on the mainland of China, and these intra-population genetic variations from different areas differ significantly. (3) The considerable genetic differentiation occurs throughout China. (4) The genetic variation among populations of O. h. hupensis is higher than that of O. h. robertsoni. (5) The patterns of genetic differentiation are basically consistent with geographical distribution of snail populations. Our results are similar to the results of allozymes and COI gene sequences, excluding a snail population from Guangxi Province (Gx-1), indicating that there are three distinct subspecies in mainland China, namely O. h. hupensis, O. h. robertsoni, and O. h. tangi. However, our results do not support that the snail population from Guangxi Province belongs to O. h. hupensis.