Project description:BACKGROUND: The detection of enteropathogens in stool specimens increasingly relies on the detection of specific nucleic acid sequences. We observed that such detection was hampered in diarrheic stool specimens and we set-up an improved protocol combining lyophilization of stools prior to a semi-automated DNA extraction. FINDINGS: A total of 41 human diarrheic stool specimens comprising of 35 specimens negative for enteropathogens and six specimens positive for Salmonella enterica in culture, were prospectively studied. One 1-mL aliquot of each specimen was lyophilised and total DNA was extracted from lyophilised and non-lyophilised aliquots by combining automatic and phenol-chloroform DNA extraction. DNA was incorporated into real-time PCRs targeting the 16S rRNA gene of Bacteria and the archaea Methanobrevibacter smithii and the chorismate synthase gene of S. enterica. Whereas negative controls consisting in DNA-free water remained negative, M. smithii was detected in 26/41 (63.4%) non-lyophilised (Ct value 28.78?±?9.1) versus 39/41 (95.1%) lyophilised aliquots (Ct value 22.04?±?5.5); bacterial 16S rRNA was detected in 33/41 (80.5%) non-lyophilised (Ct value 28.11?±?5.9) versus 40/41 (97.6%) lyophilised aliquots (Ct value 24.94?±?6.6); and S. enterica was detected in 6/6 (100%) non-lyophilized and lyophilized aliquots (Ct value 26.98?±?4.55 and 26.16?±?4.97, respectively). S. enterica was not detected in the 35 remaining diarrheal-stool specimens. The proportion of positive specimens was significantly higher after lyophilization for the detection of M. smithii (p?=?0.00043) and Bacteria (p?=?0.015). CONCLUSION: Lyophilization of diarrheic stool specimens significantly increases the PCR-based detection of microorganisms. The semi-automated protocol described here could be routinely used for the molecular diagnosis of infectious diarrhea.
Project description:Recent studies have used ethanol stool disinfection as a mean of promoting valuable species' cultivation in bacteriotherapy trials for Clostridium difficile infections (CDI) treatment with a particular focus on sporulating bacteria. Moreover, the culturomic approach has considerably enriched the repertoire of cultivable organisms in the human gut in recent years. This study aimed to apply this culturomic approach on fecal donor samples treated with ethanol disinfection to evidence potential beneficial microbes that could be used in bacteriotherapy trials for the treatment of CDI. Thereby, a total of 254 bacterial species were identified, 9 of which were novel. Of these, 242 have never been included in clinical trials for the treatment of CDIs, representing potential new candidates for bacteriotherapy trials. While non-sporulating species were nevertheless more affected by the ethanol pretreatment than sporulating species, the ethanol disinfection technique did not specifically select bacteria able to sporulate, as suggested by previous studies. Furthermore, some bacteria previously considered as potential candidates for bacteriotherapy have been lost after ethanol treatment. This study, while enriching the bacterial repertoire of the human intestine, would nevertheless require determining the exact contribution of each of species composing the bacterial consortia intended to be administered for CDI treatment.
Project description:Polycipiviridae is a recently recognized viral family within the order Picornavirales with unusual genome organization and phylogenetic placement. Viruses belonging to this family were only reported from arthropod hosts. We describe here the first full genome of a distant polycipivirus-related virus identified in frugivorous bat stools in Cambodia.
Project description:BACKGROUND: The PCR-based detection of archaea DNA in human specimens relies on efficient DNA extraction. We previously designed one such protocol involving only manual steps. In an effort to reduce the workload involved, we compared this manual protocol to semi-automated and automated protocols for archaea DNA extraction from human specimens. FINDINGS: We tested 110 human stool specimens using each protocol. An automated protocol using the EZ1 Advanced XL extractor with the V 1.066069118 Qiagen DNA bacteria card and the EZ1® DNA Tissue Kit (Qiagen, Courtaboeuf, France) yielded 35/110 (32%) positives for the real-time PCR detection of the Methanobrevibacter smithii 16S rRNA gene, with average Ct values of 36.1. A semi-automated protocol combining glass-powder crushing, overnight proteinase K digestion and lysis in the buffer from the EZ1 kit yielded 90/110 (82%) positive specimens (P?=?0.001) with an average Ct value of 27.4 (P?=?0.001). The manual protocol yielded 100/110 (91%) positive specimens (P?=?0.001) with an average Ct value of 30.33 (P?=?0.001). However, neither the number of positive specimens nor the Ct values were significantly different between the manual protocol and the semi-automated protocol (P?>?0.1 and P?>?0.1). CONCLUSION: Proteinase K digestion and glass powder crushing dramatically increase the extraction yield of archaea DNA from human stools. The semi-automated protocol described here was more rapid than the manual protocol and yielded significantly more archaeal DNA. It could be applied for extracting total stool DNA for further PCR amplification.
Project description:Biliary atresia (BA) is the leading cause of pediatric end-stage liver disease in the United States. Education of parents in the perinatal period with stool cards depicting acholic and normal stools has been associated with improved time-to-diagnosis and survival in BA. PoopMD is a mobile application that utilizes a smartphone's camera and color recognition software to analyze an infant's stool and determine if additional follow-up is indicated. PoopMD was developed using custom HTML5/CSS3 and wrapped to work on iOS and Android platforms. In order to define the gold standard regarding stool color, seven pediatricians were asked to review 45 photographs of infant stool and rate them as acholic, normal, or indeterminate. Samples for which 6+ pediatricians demonstrated agreement defined the gold standard, and only these samples were included in the analysis. Accuracy of PoopMD was assessed using an iPhone 5s with incandescent lighting. Variability in analysis of stool photographs as acholic versus normal with intermediate rating weighted as 50% agreement (kappa) was compared between three laypeople and one expert user. Variability in output was also assessed between an iPhone 5s and a Samsung Galaxy S4, as well as between incandescent lighting and compact fluorescent lighting. Six-plus pediatricians agreed on 27 normal and 7 acholic photographs; no photographs were defined as indeterminate. The sensitivity was 7/7 (100%). The specificity was 24/27 (89%) with 3/27 labeled as indeterminate; no photos of normal stool were labeled as acholic. The Laplace-smoothed positive likelihood ratio was 6.44 (95% CI 2.52 to 16.48) and the negative likelihood ratio was 0.13 (95% CI 0.02 to 0.83). kappauser was 0.68, kappaphone was 0.88, and kappalight was 0.81. Therefore, in this pilot study, PoopMD accurately differentiates acholic from normal color with substantial agreement across users, and almost perfect agreement across two popular smartphones and ambient light settings. PoopMD may be a valuable tool to help parents identify acholic stools in the perinatal period, and provide guidance as to whether additional evaluation with their pediatrician is indicated. PoopMD may improve outcomes for children with BA.
Project description:BackgroundBloody stools in a neonate may stand for a spectrum of conditions ranging from benign to life-threatening. It is critical to detect the cases that have significant underlying pathology, especially those which require urgent surgical intervention. Previous studies always focused on one particular disease related to bloody stools in neonates, or the study only involved a small number of cases. This study aimed to investigate the common causes of bloody stools in neonates.MethodsThis retrospective cohort study included the neonates admitted to our institution due to "bloody stools" over a 5-year period. We compared the differences among patients' characteristics, feeding choice, underlying diseases, and operation rate between preterm and term neonates.ResultsA total of 300 patients were included, accounting for 1.1% of the total neonatal admissions. The overall rate of exclusive breastfeeding was 28.0%. The most common underlying causes for bloody stools were: cow's milk protein allergy (CMPA, 53.3%), swallowed blood syndrome (10.0%), viral enteritis (9.7%), necrotizing enterocolitis (NEC) > stage II (8.3%), non-specific enteritis (7.3%), and anal fissure (5.0%). The median [interquartile range (IQR)] onset age for bloody stools for all infants was 12 [3-22] days after birth. Preterm neonates had a lower rate of exclusive breastfeeding (P=0.844), higher incidence of NEC > stage II (P=0.014), later bloody stools onset age (P<0.001), and longer length of hospital stay than term neonates (P<0.001). For neonates with NEC, those with bottle-fed had an earlier onset age for bloody stools than those with breast-fed (P=0.027). Only 1.7% (n=5) required surgery (2 stage III NEC, 1 post-NEC stricture, and 2 volvuli). Survival at hospital discharge was 100%.ConclusionsBloody stools in neonates is generally a benign, self-limiting disorder, not related to surgical conditions. The overall operation rate among neonates with bloody stools was only 1.7%. CMPA and NEC were the most common underlying non-surgical and surgical diseases, respectively, for neonates with bloody stools. Feeding choice is related to bloody stools in neonates, policies and strategies to support breastfeeding should be strengthened in the future.