OBJECTIVETraditional detection approaches for non-O157 STEC are both time and labour consuming in diseases surveillance. Virulence genes detection based on multiplex PCR could not only improve the detection efficiency but also increase the accuracy.

METHODSSix virulence genes of non-O157:H7 (stx1, stx2, eae, hly, etpD, katP6) were detected by two groups of trebling PCRs. The multiplex PCRs were optimized by melting curve analysis in SYBR Green I real-time PCR. Testing result of multiplex PCR was consistent with serological testing.

RESULTSThe sensitivity limits of the multiplex PCR for stx1, stx2, eaeP, etpD, katP, and hly were 10 ng/ml, 120 ng/ml, 110 ng/ml,165 ng/ml, 85 ng/ml, and 15 ng/ml, respectively, which is similar with that of single PCR. When the multiplex PCR was applied in 120 adults and 90 children diarrhea samples detection, 13 cases were detected for non-O157 positive.

CONCLUSIONThe method we established can be used for non-O157 STEC virulence genes detection and screening with high efficiency and accuracy.

Escherichia coli Infections ; diagnosis ; microbiology ; Escherichia coli Proteins ; genetics ; Humans ; Multiplex Polymerase Chain Reaction ; methods ; Shiga-Toxigenic Escherichia coli ; genetics ; isolation & purification ; Virulence Factors ; genetics

OBJECTIVETo evaluate the significance of gastric acid reflux in children with reflux esophagitis (RE).

METHODSTwenty-four-hour esophageal pH monitoring and gastroscopy were performed in 180 children suffered from vomiting. The relationship between RE, non-esophagitis (NE), non-erosive reflux disease (NERD) and gastroesophageal reflux (GER) was analyzed.

RESULTSSixty-five of the 180 patients were confirmed as having RE by endoscopy. Among them, the number of cases with grades I, II and III RE according to the diagnostic criteria by endoscopy was 37, 19 and 9 cases, respectively, while the other 115 cases were diagnosed as NE. The positive rate of acid reflux in RE group was 58.5% (38/65), while it was 42.6% (49/115) in NE group (chi(2) = 4.179, P < 0.05). All parameters of acid reflux in RE group except for the episode of reflux and the number of reflux longer than 5 min were significantly higher than those in NE group. None of the parameters of acid reflux except for Boix-Ochoa score in grade III RE patients was significantly higher than that in both grade II and grade I RE cases. However, the difference in acid reflux parameter between grade I and grade II RE patients had not reached statistical significance. The results also showed that the positive rate of pathological acid reflux was 48.3% (87/180). Among them, 38 cases were RE, while other 49 cases were NERD. The difference in acid reflux between these two groups was not significant.

CONCLUSIONSGastric acid reflux may play a major role in the development of RE in children, but may not be a sole pathogenic factor. The degree of acid reflux is not closely correspondent to the severity of RE. Acid reflux may not completely contribute to RE. Gastroscopy is very important for patients with reflux symptom.

Adolescent ; Child ; Child, Preschool ; China ; Esophageal pH Monitoring ; Esophagitis, Peptic ; diagnosis ; etiology ; pathology ; physiopathology ; Esophagoscopy ; Female ; Gastric Acid ; secretion ; Gastroesophageal Reflux ; complications ; Humans ; Hydrogen-Ion Concentration ; Infant ; Male ; Severity of Illness Index