A Study on Detecting and Identifying Enteric Pathogens With PCR

Objective To develop a rapid and definite diagnostic test of bacterial enteritis caused by pathogenic enterobacteria, the most frequent etiologic agent of infectious enteritis in the world. Methods A set of conventional PCR assays were applied to detect and identify salmonella, shigella, and E. coli O157:H7 directly from pure culture and fecal samples. The general primers of pathogenic enterobacteria were located on the uidA gene, which were found not only in E. coli nuclear acid, but also in Shigella and salmonella genes. Shigella primer was from ipaH gene whose coded invasive plasmid relative antigen existed both in plasmid and in genome. The primers of salmonella were designed from the 16SrRNA sequence. The primer of E.coli O157:H7 was taken from eaeA gene. Five random primers were selected for RAPD. The detection system included common PCR, semi-nested PCR and RAPD. Results This method was more sensitive, specific and efficient and its processing was rapid and simple. For example, the method could be used to specifically detect and identify salmonella, shigella, and E. coli O157:H7, and its sensitivity ranged from 3 to 50 CFU, and its detection time was 4 hours. Conclusion This PCR method, therefore, can serve as a routine and practical protocol for detecting and identifying pathogenic microorganisms from clinical samples.

Samonella typhi infection-related appendicitis:A case report

BACKGROUND Acute appendicitis is one of the most common acute abdominal emergencies around the world,which is always associated with infection.Infection with Salmonella typhi,an enteric pathogen,is a rare cause of acute appendicitis.We here report a patient with acute appendicitis associated with Samonella typhi infection,accompanied with spleen and kidney infarction,providing a rare example for a common surgical emergency.CASE SUMMARY A 25-year-old Pakistani man presented to the hospital with a 3-d history of fevers,vomiting,and abdominal pain.Computed tomography(CT)revealed a thickened intestinal wall of the ileocecal junction with multiple enlarged lymph nodes nearby.He was diagnosed with acute appendicitis and received laparoscopic appendectomy,which showed mild inflammation of the appendix.After the surgery,the patient presented again with a high fever(>39℃)and diarrhea.A CT angiography scan indicated spleen and kidney infarction.According to the blood culture,the diagnosis was finally clear to be Samonella typhi infection.The pyrexia and enteric symptoms were relieved after the application of intravenous levofloxacin.CONCLUSION This case,characterized by the combination of Salmonella typhi infection,acute appendicitis,and renal and splenic infraction,serves as a rare example for a common surgical emergency.

Catheter-related bloodstream infections in children with intestinal failure: a 6-year review from an intestinal rehabilitation center in China

Background Children with intestinal failure(IF)have frequent catheter-related bloodstream infections(CRBSIs).This study aimed to analyze the clinical presentation and laboratory parameters of CRBSIs in children with IF.Methods This 6-year retrospective study was conducted among IF children with CRBSIs at an intestinal rehabilitation center in China.Clinical data were collected,including data of temperature and gastrointestinal symptoms.Blood/catheter culture,fecal tests,and calculation of inflammatory index were performed,which were obtained within 1 week since CRBSI onset.Results Fifty children with 87 CRBSIs were identified,of which there were 17 suspected and 70 confirmed cases.Seventy-two pathogens were cultured from 70 positive blood cultures:63%were Gram-positive organisms,23%were Gram-negative organisms,and 11%were fungal organisms.Overall,48.6%were enteric organisms;47.2%of bacterial pathogens were consistent between fecal and blood cultures.Moreover,46.3%fecal routines showed abnormalities including increased white blood cells,occult blood positive and the presence of fat droplets.The consistent symptom at onset of CRBSIs was fever and gastrointestinal symptoms including increased stool output,abdominal distension,or both.C-reactive protein(CRP)and procalcitonin(PCT)were elevated,i.e.,16.5 mg/L[interquartile range(IQR)8.7-44.7]and 0.48 ng/mL(IQR 0.2-1.76),respectively.Conclusions IF children had a high rate of CRBSIs,of which larger proportions were due to Gram-positive and enteric organisms.Fever and/or gastrointestinal symptoms,combined with elevated CRP and PCT,is conducive to the early diagnosis of CRBSIs in IF patients.