[Clinical and gastroscopic features of children with cyclic vomiting syndrome: an analysis of 63 cases]. / 儿童周期性呕吐综合征63例临床与胃镜分析.

OBJECTIVES: To study the clinical and gastroscopic features of children with cyclic vomiting syndrome. METHODS: A retrospective analysis was performed on the medical data of 63 children with cyclic vomiting syndrome who were hospitalized and followed up in Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University from August 2019 to March 2022. RESULTS: Among the 63 children, there were 30 boys and 33 girls, with a mean age of 6.11 years, a mean course of disease of 2.57 years, and a mean vomiting period of 4.04 days. The most common accompanying symptom was listlessness or somnolence (55/63, 87%), followed by anorexia (45/63, 71%), abdominal pain or abdominal discomfort (40/63, 63%), constipation (19/63, 30%), salivation (12/63, 19%), nausea (11/63, 17%), headache (11/63, 17%), fever (6/63, 10%), and rash (1/63, 2%). All 63 children underwent gastroscopy, among whom 3 had no marked abnormalities, 22 (35%) had chronic superficial gastritis or chronic non-atrophic gastritis alone, and 38 (60%) had other abnormal changes aside from chronic gastritis (16 children with reflux esophagitis, 12 with bile reflux gastritis, 13 with duodenitis, 10 with erosive gastritis, and 5 with gastric or duodenal ulcer). Among the 63 children, 42 underwent pathological examinations of gastric mucosa, among whom 5 had no marked abnormalities, 34 had mild chronic gastritis, 2 had moderate chronic gastritis, and 1 had severe chronic gastritis. Among the 63 children, 15 received 24-hour dynamic esophageal pH monitoring during the interictal period, among whom 9 children were found to have pathological acid reflux. CONCLUSIONS: In addition to recurrent vomiting, most children with cyclic vomiting syndrome also have the symptoms such as somnolence or listlessness, anorexia, and abdominal pain. The main manifestation on gastroscopy is chronic gastritis, and most children may also have reflux esophagitis, bile reflux gastritis, and erosive gastritis. Mild chronic gastritis is the main pathological change of gastric mucosa.

[Risk factors of Clostridium difficile-associated diarrhea in children].

OBJECTIVE: To explore the risk factors of Clostridium difficile-associated diarrhea (CDAD) in children. METHODS: From December 2010 to March 2011, the hospitalized diarrheal patients under 18 years old at Beijing Children's Hospital were tested for Clostridium difficile. The CDAD(+) patients were selected and their fecal specimens were PCR-positive for tcdA and (or) tcdB genes. And the patients with healthcare facility-associated-CDAD (HCFA-CDAD) were selected from the group of CDAD(+). The CDAD patients were selected and their fecal specimens were PCR-negative for tcdA and (or) tcdB genes. And the 1:3 matched controls per case were selected from those hospitalized patients without diarrhea at the same department with similar diseases during the same period. The potential predictors of CDAD included age, gender, co-morbidities, prior hospitalization, the administration of C. difficile-active antibiotics during prior 24 hours, recent (< 1 month) exposure to antibiotics or acid-blocking medications or nonsteroidal anti-inflammatory drug (NSAID), C-reactive protein (CRP) and white blood cell (WBC), etc. Multivariate Logistic regression models were created to identify the independent predictors of CDAD. RESULTS: Among 93 PCR tests, 35 were positive in fecal samples. There were HCFA-CDAD (n = 30) and CDAD(-) (n = 58). Thirty-five CDAD(+) hospitalized patients were compared with 105 controls. According to multivariate analyses, the predictors of CDAD included prior hospitalization (P < 0.01, OR = 0.002), CRP(P = 0.008, OR = 3.465), NSAID (P = 0.015, OR = 13.950) and WBC (P = 0.003, OR = 8.063). CONCLUSION: The administration of NSAID, elevated CRP and abnormal WBC are significantly associated with CDAD.

[Follow-up of pediatric inflammatory bowel disease].

OBJECTIVE: To analyze the clinical characteristics and prognosis of pediatric inflammatory bowel disease (IBD) through a long-term follow-up so as to improve the diagnosis and management of IBD in children. METHODS: Seventy-three IBD patients admitted into our hospital from May 2000 to September 2010 were re-evaluated with the uniform diagnostic criteria proposed by the 2010 consensus diagnostic criteria for pediatric IBD. All patients were followed up by questionnaire, telephone and face-to-face interview. RESULTS: Among them, 56 cases (76.7%) (ulcerative colitis (UC): n = 34, Crohn's disease (CD): n = 22) were available for follow-up study. Among 34 UC cases, 13 cases had their diagnosis confirmed and 21 cases were diagnosed as probable UC. Meanwhile, among 22 CD cases, 14 and 8 had definite and probable diagnoses respectively. At diagnosis, 46.9% (15/32) of UC patients had extensive colitis, 40.6% (13/32) left-sided colitis while 72.7% (16/22) of CD patients with had ileocolonic. And 28 cases (82.4%) of UC patients and 20 cases (90.9%) of CD patients fulfilled the criteria for moderate to severe grade. Among 56 IBD cases, there was no death for CD, but 5 died for UC (14.7%). In the remaining 29 UC and 22 CD patients, 16 cases (55.2%) and 15 cases (68.2%) stayed symptom-free (P > 0.05). Moreover, 8 cases (27.6%) of UC and 3 cases (13.6%) of CD patients belonged to chronic relapsing type while 16 cases (55.2%) of UC and 15 cases (68.2%) of CD patients were of chronic persistent type. The physical activities of most IBD patients (n = 49) were unrestricted. The surgical rate for IBD was 19.6% (n = 11), 8.8% for UC (n = 3) and 36.4% for CD (n = 8) (P < 0.05). The incidences of surgical complications such as intestinal obstruction, intestinal perforation and hemorrhage of gastrointestinal tract were 7.1% (n = 4), 7.1% (n = 4) and 1.8% (n = 1). And it was more common in the CD group. CONCLUSIONS: Most IBD patients belong to chronic persistent type and then chronic relapsing type. Their physical activities are unrestricted. The surgical rate for CD is significantly higher than UC. And surgical complications such as intestinal obstruction, intestinal perforation and hemorrhage of gastrointestinal tract occur more frequently in the CD group.

Combination of Tumor Mutational Burden and Specific Gene Mutations Stratifies Outcome to Immunotherapy Across Recurrent and Metastatic Head and Neck Squamous Cell Carcinoma.

Purpose: To investigate the prognostic significance of tumor mutational burden (TMB) combined with specific prognosis-related gene mutations in immunotherapy for recurrent and metastatic head and neck squamous cell carcinoma (r/m HNSCC). Methods: One hundred thirty-two r/m HNSCC patients from the Morris and Allen cohorts had undergone immunotherapy. We constructed the immunotherapy-related gene prognostic index TP-PR combining TMB and PIK3CA, TP53, or ROS1 mutation. And we analyzed the differences in overall survival (OS) and immune cell infiltration between samples in different groups. The association of each signature's single-sample gene set enrichment analysis scores with TP-PR was tested using Spearman's correlation test. Results: The median OS of the patients with high TMB (TMB ≥10 mut/Mb) who received immunotherapy for r/m HNSCC was 2.5 times as long as that of the patients with low TMB (25 vs. 10 months). More importantly, the high TP-PR (TP-PR >0) group had better median OS (25 vs. 8 months) than the low TP-PR (TP-PR ≤0) group. CD8+ T cells and activated memory CD4+ T cells in the tissues of the patients with high TP-PR were higher than those in the patients with low TP-PR. Results showed that TP-PR stratification had a higher area under the curve (AUC) value (0.77, 95% CI 0.86-0.68) compared with TMB stratification (0.56, 95% CI 0.68-0.44). The differential gene expression in the high and low TP-PR groups mainly influenced metabolism-related signaling pathways. Conclusion: TP-PR was an effective predictor of immunotherapy outcome for r/m HNSCC, which might be better than TMB alone. Patients with high TP-PR had a better survival benefit than had the patients with low TP-PR.

The effect of adding concurrent chemotherapy to radiotherapy for stage II nasopharyngeal carcinoma with undetectable pretreatment Epstein-Barr virus DNA: Retrospective analysis with a large institutional-based cohort.

Little is known about the value of adding concurrent chemotherapy (CC) to radiotherapy for stage II nasopharyngeal carcinoma (NPC) with undetectable (0 copies/mL) pretreatment Epstein-Barr Virus (EBV) DNA in the intensity-modulated radiotherapy (IMRT) era. To address this question, the present study retrospectively reviewed 514 patients with newly diagnosed stage II NPC and undetectable pretreatment EBV DNA from Sun Yat-sen University Cancer Center between March 2008 and October 2016. Clinical characteristics and survival outcomes between concurrent chemoradiotherapy (CCRT) and IMRT alone groups were compared. Propensity score matching analysis was conducted to control for confounding factors. Although CCRT group had significantly higher proportions of stage N1 disease than IMRT alone group before matching (85% vs. 61%, p < 0.001), no statistically significant differences were noted for OS (97.8% vs. 98.1%, p = 0.700), DFS (93.4% vs. 94.5%, p = 0.846), DMFS (96.0% vs. 96.9%, p = 0.762), and LRFS (97.3% vs. 98.1%, p = 0.701). After 1:1 propensity-score matching, 177 pairs were identified. Patients in each group were found to be well balanced in baseline characteristics and risk factors (all P > 0.05). The five-year OS (96.9% vs. 98.2%, p = 0.302), DFS (92.0% vs. 95.2%, p = 0.777), DMFS (95.2% vs. 97.6%, p = 0.896), and LRFS (97.3% vs. 97.6%, p = 0.328) rates remain comparable for both CCRT and RT alone groups. Additionally, subgroup analysis still failed to observe any significant survival benefit for the addition of CC to IMRT for N1 disease (P>0.05 for all). Our results indicated that IMRT alone appeared to achieve comparable survival to CCRT for stage II NPC with undetectable pretreatment EBV DNA.

Pathological and genomic phenotype of second neuroendocrine carcinoma during long-term follow-up after radical radiotherapy for nasopharyngeal carcinoma.

BACKGROUND: Second head and neck neuroendocrine carcinoma (NEC) after radical radiotherapy for nasopharyngeal carcinoma (NPC) treatment is rarely reported. The prognosis of second cancer is poor, and our research focuses on finding a breakthrough in the treatment. In this study, we aimed to investigate clinicopathological characteristics and to identify the genomic landscape of second head and neck NECs. METHODS: We collected five second head and neck NEC cases in the recent three years from our patient database. Clinicopathological data and images were obtained. Genomic analysis was performed using high-throughput second generation sequencing. KEGG pathway enrichment analyses between high-frequency mutations were performed using the STRING database. RESULTS: All patients had been diagnosed with second NEC, according to the pathological observations. The interval between diagnosis of NPC and NEC ranged from 10 to 18 years. Two patients had brain or liver metastasis at three and nine months, respectively, after the diagnosis of NEC. Three patients died of the disease with the overall survival time ranging from three to nine months. Commonly altered genes (50%) in second head and neck NECs included TP53, RB1, NOTCH2, PTEN, POLG, KMT2C, U2AF1, EPPK1, ELAC2, DAXX, COL22A1, and ABL1. Those genetic lesions might affect p53 signaling, MAPK signaling, PI3K-Akt signaling, sphingolipid signaling, and neurotrophin signaling pathways. CONCLUSIONS: Second head and neck NECs had poor prognosis. We revealed, for the first time, the mutational landscape, high-frequency somatic mutations, and potential signaling pathways of second head and neck NECs. Its optimal treatment model needs to be further studied in future clinical trials.

[Prevalence of plasmid-mediated AmpC beta-lactamases in Escherichia coli and Klebsiella spp. isolated in children].

OBJECTIVE: To study the plasmid-mediated AmpC ß-lactamases and the genotypes of Escherichia coli and Klebsiella spp. in children. METHODS: Escherichia coli and Klebsiella spp. of strains were isolated at our division from January to December 2009. Cefoxitin disk diffusion method was used to screen Escherichia coli and Klebsiella spp. for phenotypic AmpC enzyme. Multiple PCR method was adopted to test the genotypes of AmpC enzyme-positive Escherichia coli and Klebsiella spp.strains. RESULTS: Of all Escherichia coli and Klebsiella spp., 65 were insensitive to cefoxitin disk and 17 strains carried DHA type AmpC gene. The prevalence of plasmid-mediated AmpC enzyme in Escherichia coli and Klebsiella spp. was 26.2% (17/65). Among plasmid-mediated AmpC enzyme isolates, 14 (38.9%) Klebsiella pneumoniae strains, 2 (7.7%) Escherichia coli strains and 1 (33.3%) Klebsiella oxytoca strains carried the DHA-1 AmpC gene. The genes of MOX, CIT, DHA, ACC, MIR and FOX were not found in other 48 strains. CONCLUSIONS: The identified plasmid-mediated AmpC genes are all of DHA-1 genotype in Escherichia coli and Klebsiella spp. The prevalence of plasmid-mediated AmpC enzyme in Klebsiella pneumoniae isolates is relatively high in children.

[Diagnostic value of reflux disease questionnaires in children with gastroesophageal reflux disease].

OBJECTIVE: To evaluate the value of reflux diagnostic questionnaire in the diagnosis of children with gastroesophageal reflux disease (GERD). METHODS: Forty-five children aged 7-16 years old referred for suspected GERD with vomiting/regurgitation, nausea, heartburn/retrosternal pain, abdominal pain, epigastric pain, acid regurgitation and pain while swallowing were assessed. Each symptom was rated from 0 to 3 according to its severity and frequency. The items of questionnaire were validated against the results from upper gastrointestinal endoscopy and esophageal 24 h pH monitoring. And the results were compared with symptom scores to determine the threshold value for GERD. RESULTS: In 45 patients, the ratio of male to female was 1.37:1 and the mean age (11.1±2.6) years old. Composite score in 23 patients with GERD (20±10) was significantly higher than that in 22 patients without GERD (13±4) (P<0.05). There was no significant difference of composite scores among patients with grades 0, I, II and III according to upper gastrointestinal endoscopy (P>0.05). With 13.0 as threshold score for GERD, the sum of sensitivity and specificity was maximal. The area under the receiver operating characteristic curve (ROC) was 0.79 while true positive diagnostic rate 72.0% and true negative diagnostic rate 75.0% with a sensitivity of 78.3%, a specificity of 68.2% and an accuracy of 73.3%. CONCLUSION: Reflux diagnostic questionnaire is a suitable method in initial diagnosis of GERD. It may serve as a screening test for GERD in 7-16-year-old children.

The mechanism of wet/dry torrefaction pretreatment on the pyrolysis performance of tobacco stalk.

In this work, the influence of dry/wet torrefaction with additives on the pyrolysis performance was investigated. The results showed that the content of phenols and ketones (62% and 42%) was improved and the content of acids decreased from 35% to 4% due to the increase of lignin content in torrefied char. Moreover, the content of aromatic hydrocarbon reached 22%. The mechanism showed that the conversion of "CO/CO" into states of "aromatic CC/CC", the removal of hemicellulose and the formation of pseudo-lignin during wet/dry torrefaction were the key factors for the enrichment of aromatic hydrocarbon. The research supplied an effective and original method for obtaining high value aromatic chemicals from the agricultural and forestry waste via the wet/dry torrefaction pretreatment combining with pyrolysis.

Clinical features and survival outcomes between ascending and descending types of nasopharyngeal carcinoma in the intensity-modulated radiotherapy era: A big-data intelligence platform-based analysis.

PURPOSE: To compare clinical features and survival outcomes in patients with ascending type (type A) and descending type (type D) nasopharyngeal carcinoma (NPC) in the intensity-modulated radiotherapy (IMRT) era. MATERIALS AND METHODS: A total of 5194 patients with type A and type D NPC treated at Sun Yat-sen University Cancer Center were randomly selected. Tumors that were mainly advanced local disease (T3-4 stage) with early stage cervical lymph node involvement (N0-1 stage) were determined as type A, while tumors with advanced lymph node disease (N2-3 stage) but early stage local invasion (T1-2 stage) were classified as type D NPC. Kaplan-Meier's analysis was used to evaluate survival rates, and log-rank test survival curves were used for comparison. In the multivariate analysis Cox proportional hazard models were developed. RESULTS: There was a larger proportion of type A tumors (82%) than type D tumors (18%). Compared to patients with type A tumors, those with type D tumors had increased likelihood of distant metastasis, regional recurrence, disease recurrence, and death (P < 0.001 for all), however, not for local recurrence (P < 0.001). The HR (hazard ratio) for death following recurrence of disease for type D tumors were 1.6 compared to type A tumors. Multivariate analysis revealed that elevated EBV DNA, elevated lactate dehydrogenase, alcohol consumption, and no family history of cancer attributed to the development of type D tumors. Annual hazard rate in type A patients increased, peaking at 12-18 months after initial treatment and downward thereafter. Similar trend also occurred in type D during the first 5 years following treatment. Notably, a minor peak was also observed 7-8 years post treatment. CONCLUSIONS: In the IMRT era, recurrence patterns differed across tumor types. Type D NPC had a more aggressive clinical course and worse outcomes compared with type A NPC.

Characterization of multidrug-resistant and metallo-beta-lactamase-producing Pseudomonas aeruginosa isolates from a paediatric clinic in China.

BACKGROUND: In the present study, we characterized multidrug-resistant Pseudomonas aeruginosa (MDRP) clinical isolates from a paediatric facility and investigated the types and features of the metallo-beta-lactamases (MBLs) produced by carbapenem-resistant strains. METHODS: Four hundred and ninety-eight strains of Pseudomonas aeruginosa were isolated from patients at Beijing Children's Hospital between January 2005 and December 2006. The minimal inhibition concentrations (MICs) of the strains for 13 antibiotics were measured. A combination of the E test and PCR amplification/DNA sequencing was used to define the carbapenem-resistant strains. RESULTS: We found that 24.1% (120/498) of the isolates were MDRP. The frequencies of resistance to imipenem and meropenem were 34.2% and 35.8%, respectively, and the MIC50 and MIC90 values for the two antibiotics were identical at 4 microg/ml and 32 microg/ml, respectively. The detection rate for carbapenem resistance was 49.2% (59/120). Among the 59 carbapenem-resistant Pseudomonas aeruginosa strains, 39 (66.1%) were positive for the MBL genotype; 35 (89.7%) strains carried the bla(IMP) gene and 4 (10.3%) strains carried the bla(VIM) gene. Neither bla(SPM) nor bla(GIM) was amplified from any of the 59 isolates. DNA sequencing revealed that IMP-1 was present in 35 IMP-producing isolates and VIM-2 was detected in four VIM-producing isolates. CONCLUSIONS: These MDRP isolates exhibited high frequencies of resistance to carbapenems among clinical isolates from a paediatric facility in Beijing, China. The production of MBL appears to be an important mechanism for carbapenem resistance in Pseudomonas aeruginosa.

[Analysis of resistant genes of beta-lactam antibiotics from Pseudomonas aeruginosa in pediatric patients].

OBJECTIVE: To analyze the antibiotic resistance of the Pseudomonas aeruginosa (PA) isolated from pediatric patients and the resistant genes of beta-lactam antibiotics thereof. METHODS: 146 PA strains were isolated from pediatric patients. Agar dilution method recommended by the Clinical and Laboratory Standards Institute was used to examine the minimum inhibitory concentrations (MICs) of 12 antimicrobial agents, including the penicillins, third and fourth genet ration cephalosporins, carbapenemase, Aztreonam, beta-lactamase inhibitors, quinolones, and aminoglycosides. PCR was used to detect the expression of the genes TEM, SHV, OXA, PER, GES, CTX-M, IMP, VIM, DHA, MIR, FOX, and oprD2. RESULTS: The multi-drug resistance rates against different antibiotic were high among the 146 PA strains. The rates of imipenem and meropenem resistance were 41.1% and 35.6% respectively. Among the 146 PA strains, 46 (31.5%) were positive for the MBL genotype; 38 (82.6%) carried the blaIMP gene, 8 (17.4%) carried the blaVIM gene, and 114 (78.1%) were oprD2 negative. The genes TEM, SHV, OXA, CTX-M, PER, VEB, GES, FOX, MIR, and DHA were not found in all strains. CONCLUSION: Many PA isolated from pediatric patients carry the genes IMP or VIM and losses oprD2 gene related to the expression of the outer membrane porin OprD2. The loss of the gene oprD2 is essential mechanism of beta-lactam antibiotics resistance in PA.

[Prevalence of extended-spectrum beta-lactamase producing Escherichia coli in pediatric patients in China].

OBJECTIVE: To study the drug resistance profiles of extended spectrum beta lactamase (ESBL) producing Escherichia coli (E. coli) and provide guidance for pediatric clinical prescription. METHODS: 5127 strains of ESBL producing E. coli were isolated from 5 children's hospitals in Beijing, Shanghai, Chongqing, and Guangzhou. The minimum inhibitory concentration (MIC) values of 349 strains to 9 antibiotics most in use in pediatrics were measured with agar dilution method. RESULTS: The prevalent rate of ESBL producing of E. coli was 46.7%. The resistant rates to ampicillin/clavulanic acid, cefotaxime, ceftazidime, and cefepime were 23.1%, 67.2%, 24.5%, and 48.4% respectively, and the intermediate rates were 38.5%, 26.4%, 5.7%, and 19.1% respectively. The resistant rate to amikacin was 5.4%. All the strains were susceptible to imipenem. The MIC90 values of ampicillin, cefotaxime, cefepime, ciprofloxacin, and gentamicin were 256 mg/L or higher. There were differences in the resistance profile to ampicillin/clavulanic acid, cefepime, ciprofloxacin, and gentamicin among different regions. CONCLUSION: ESBL is extensively prevalent among the E. coli strains isolated from the pediatric clinic that are resistant to most antimicrobial agents except imipenem and amikacin. Regional difference exists in drug resistance to some agents exist.

Dose Escalation of Lobaplatin Concurrent with IMRT for the Treatment of Stage III-IVb NPC: A Phase I Clinical Trial.

The maximum tolerated dose (MTD) of lobaplatin as a single agent chemotherapy concurrent with intensity-modulated radiotherapy (IMRT) in Asian population with nasopharyngeal carcinoma (NPC) remains unclear. From June 2016 to December 2017, 17 patients diagnosed with stage III-IVb NPC from an Asian population were prospectively enrolled. Patients were administered lobaplatin with 25-50 mg/m2 escalation of dosage on day 1. Every 21 days (days 1, 22, and 43) during radiotherapy, cycles were repeated. We administered radiotherapy as 2.12-2.27 Gy per fraction with five daily fractions each week for 6 to 7 weeks. The evaluation of lobaplatin-related toxic effects was based on the Common Terminology Criteria for Adverse Events version 4.0. During the weekly treatment period, complete blood counts and biochemistry were performed. Dose-limiting toxicities (DLTs) were determined by the following events during any cycle in which lobaplatin was administered. Each dose group consisted of at least three cases. We proceeded to the subsequent dose group in the absence of DLT with a dose increment of 5 mg/m2 until DLT occurred. Periods from 1 week prior to the chemotherapy initiation to 3 weeks after the last chemotherapy were defined as DLT observation periods. MTD was determined by the dose that was immediately below the dose that produced DLT. After analysis, DLT occurred in three patients, including a group with two of three patients in 45 mg/m2 lobaplatin and another group with one of five patients in 40 mg/m2 lobaplatin. No grade 3-4 toxicity was observed in patients treated with lobaplatin <40 mg/m2. The tumor response rate at 12 weeks after treatment was 100%. In summary, lobaplatin concurrent with IMRT was active in stage III-IVb NPC, and the MTD for the lobaplatin as single-agent chemotherapy was 40 mg/m2 when combined with IMRT in an Asian population. This trial is registered with ClinicalTrials.gov, number NCT03188497.

[Transfer of erythromycin-resistance among strains and species of bacteria: plasmid conjugation method in enterococcal isolates].

OBJECTIVE: To study if the resistance to macrolide in Enterococcus can be transferred between strains, and species of the same and different genera. METHODS: Agar dilution was used to screen 30 enterococcal isolates that were resistant to erythromycin. Conjugation was performed by filter mating method. The 30 donor bacteria included 13 strains of Enterococcus faecalis, 16 strains of E. faecium, and 1 strain of E. hirae. The recipient bacteria included 1 strain of E. faecalis sensitive to erythromycin and resistant to tetracycline, and 1 strain of Staphylococcus aureus with the MIC against erythromycin of 0.25 approximately 1 microg/ml. Polymerase chain reaction was used to test the existence of ermB gene and the tranposons Tn1545 and Tn917 in the enterococcal isolates before and after filter mating. RESULTS: The transfer rate between different strains and species of the same genus were all 100%. The MIC(50) and MIC(90) against erythromycin of 13 conjugates were both 512 microg/ml, and Tn1545 and Tn917 were found in the ermB gene of 12 conjugates. 17 conjugates were obtained from 16 strains of donor E. faecium and 1 strain of E. hirae with the MIC(50) and MIC(90) both of 512 microg/ml. The ermB gene was found in 16 of the 17 conjugates, and 11 of the 16 conjugates showed the existence of Tn1545 and Tn917, Tn1545 existed in the ermB gene of 4 conjugates, and Tn917 existed in the ermB gene of 1 conjugate. 30 conjugates of Staphylococcus aureus were obtained by plasmid conjugation and transfer with a transfer rate of 100% and the MIC(50) and MIC(90) both of 512 microg/ml. The ermB gene was found in 28 of the 30 conjugates. Both Tn1545 and Tn917 were found in the ermB gene of 23 of the 28 conjugates, Tn1545 was found in the ermB gene of 4 conjugates, and Tn917 was found in the ermB gene of 1 conjugate. CONCLUSION: The resistance to macrolide of Enterococcus, related with the existence of ermB gene and transposons Tn1545 and Tn917, can be transferred between strains and species of same and different genera.

Characterization of erythromycin-resistant Streptococcus pneumoniae isolates causing invasive diseases in Chinese children.

BACKGROUND: Erythromycin-resistant Streptococcus pneumoniae isolates that causing invasive pneumococcal diseases (IPD) in Chinese children remain uncharacterized. This study aims to identify the resistance genes associated with erythromycin resistance and to determine the genetic relationships of IPD isolates in Chinese children. METHODS: A total of 171 S. pneumoniae strains were isolated from 11 medical centers in China from 2006 to 2008. All the isolates were characterized via serotyping and antibiotic susceptibility determination. The erythromycin-resistant isolates were further characterized via ermB and mefA gene detection, multi-locus sequence typing analysis, and pulsed-field gel electrophoresis. RESULTS: A total of 164 (95.9%) isolates showed resistance to erythromycin, of which 162 strains with high high-level resistance (MIC ≥ 256 µg/ml). A total of 104 (63.4%) isolates carry the ermB gene alone, whereas 59 (36.0%) harbor both ermB and mefA genes. Of the 59 strains, 54 were of serotypes 19A and 19F and were identified as highly clonal and related to the Taiwan(19F)-14 clone. CONCLUSIONS: The erythromycin resistance rate in IPD isolates is significantly high and is predominantly mediated by the ermB gene. Isolates that carry both ermB and mefA genes are predominantly of serotypes 19A and 19F.

[Detection and drug resistance analysis of extended-spectrum beta-lactamases-producing Shigella in pediatric patients].

OBJECTIVE: To investigate the occurrence and drug resistance of extended-spectrum beta-lactamases (ESBLs)-producing strains of Shigella in pediatric patients, so as to provide information for clinical treatment. METHOD: A total of 59 strains of Shigella were isolated from stool specimens of hospitalized children with shigellosis from January 2004 to December 2008. The broth dilution test recommended by Clinical and Laboratory Standards Institute (CLSI) was performed to detect the ESBLs producers. Susceptibility test was carried out by agar dilution method. Escherichia coli ATCC25922 and Klebsiella pneumonia ATCC700603 were used as quality control strains. RESULT: Of the 59 isolates, 21 (35.6%) strains were identified as ESBLs producers. All of the 21 strains were detected by cefotaxime and cefotaxime/clavulanic acid, only 5 (23.8%) were detected by ceftazidime and ceftazidime/clavulanic acid. Both ESBLs and non-ESBLs producers showed high resistance to penicillins. The resistance of ESBLs-producing strains to third and fourth-generation cephalosporins, aztreonam was significantly higher than that of non-ESBLs-producing strains, as well as sulphonamides and quinolones. The drugs sensitive to ESBLs producers were imipenem, meropenem, piperacillin/tazobactam, cefoperazone/sulbactam and cefoxitin, with resistance rate of 0.0%, 0.0%, 14.3%, 9.5%, 14.3%, respectively. CONCLUSION: The prevalence of ESBLs-producing Shigella in pediatric patients is at a high level in this area, and the enzyme-producing strains are multidrug resistant. It is recommended that the detection of ESBLs in Shigella should be carried out by microbiological laboratories. Any of the above 5 antibiotics of low resistance should be used according to the patient's condition.

[Study on the distribution and correlation of trace elements in whole blood of children in Beijing].

OBJECTIVE: To study the distribution and correlation of trace elements in peripheral blood of children in Beijing so as to offer scientific evidence for the supplementation of trace elements and to prevent lead intoxication. METHODS: Contents of trace elements in whole blood of 13 929 children in Beijing region were detected by Atomic Absorption Spectrometer. According to developmental condition, children were divided into young infancy group, infancy group, toddler's age group, preschool age group, school age group and adolescence group. Every group was divided into males and females. Distribution and correlation of trace elements in different age groups and in different sex sets were then analyzed and compared. RESULTS: The level of copper, calcium and magnesium were stable in different age groups and in different sex sets. There were no obvious significant differences in age groups and sex sets and there were no deficiency of copper, calcium and magnesium discovered. The level of zinc increased gradually following the growth of age and the level of zinc was (81.71 +/- 15.91) micromol/L. There were significant differences in different age groups noticed as well in sex sets of infancy group, toddler's age group and preschool age group. The rate of deficiency of zinc decreased gradually following the growth of age. The rate of zinc deficiency was 13.7% and there were obvious differences noticed in sex sets of toddler, preschool and school age groups. The level of iron increased gradually following the growth of age with the level of iron as (8.28 +/- 0.78) mmol/L. There were significant differences noticed in different age groups, after infancy stage. There was significant difference noticed also in sex sets after school age group. The rate of iron deficiency decreased obviously following the growth of age. The iron deficiency rate was 12.9%, and significantly different in sex sets of young infancy, school age and adolescence groups. The level of lead increased gradually following the growth of age, with the overall level as (59.97 +/- 26.52) microg/L; There was an obvious significant differences noticed in different age groups with significant differences noticed in sex sets after toddler's age group. The rate of lead intoxication increased gradually following the growth of age. The rate of lead intoxication was 8.2%. There were significant differences noticed in sex sets after toddler's age group. However, there were negative correlations noticed among the levels of lead and copper, zinc, calcium, magnesium and iron. There were no correlations between the level of calcium and iron found but showed positive correlation among other trace elements. CONCLUSION: The deficiency of calcium was basically corrected but the deficiency of zinc and iron were still obvious. There was a high level of lead noticed in these children. It is important to advocate on healthy feeding program, on culture good hygienic habit and on away from the lead pollution sites.

[Frequency of ABO type IgM antibody in 276 infants younger than six months].

The aim of study was to explore the frequency of ABO type IgM antibody in infants younger than six months. 309 hospitalized infants younger than six months were selected at first and their EDTA K(3) anticoagulant blood samples were taken. All the infants were divided into five groups: neonates within 1 week as group I; neonates aged 8 to 14 days as group II; neonates aged 15 days to 1 month as group III; infants aged two to 3 months as group IV and infants aged 4 to 6 months as group V. The monocolonal anti-A, anti-B serums, A cells, B cells and O cells were utilized to carried out the blood typing with tube test. The results indicated that from 309 samples tested 33 AB type sample were excluded. Out of the remains of 276 samples, 29 of 46 samples in group I were positive and with the ABO type consistent rate 63% (29/46); 41 of 64 samples in group II were positive and with the ABO type consistent rate 64% (41/64); 47 of 74 samples in group III were positive and with the ABO type consistent rate 63% (47/74); 28 of 45 samples in group IV were positive and with the ABO type consistent rate 62% (28/45); 40 of 47 samples in group V were positive and with the ABO type consistent rate 85%. It is concluded that the ABO type IgM antibody appear in most infants younger than six months and these IgM antibodies may be regarded as the important evidence for ABO typing in infants.