Young children cannot easily produce sputum for diagnosis of pulmonary tuberculosis. Alternatively, Mycobacterium tuberculosis complex (MTB) bacilli can be detected in stool by using the Xpert MTB/RIF (Ultra) assay (Xpert). Published stool processing methods contain somewhat complex procedures and additional supplies. The aim of this study was to develop a simple one step (SOS) stool processing method, based on gravity sedimentation only, similar to sputum Xpert testing for the detection of MTB in stool. We first assessed if the SOS stool method could provide valid Xpert results without the need of bead-beating, dilution and filtration steps. We concluded that this was the case and, subsequently, validated the SOS stool method by testing spiked stool samples. By using the SOS stool method, of the 29 spiked samples, 27 gave valid Xpert results and MTB was recovered from all 27. The proof of principle of the SOS stool method was demonstrated in a routine setting in Addis Ababa, Ethiopia. Nine of 123 children with presumptive TB were MTB positive on nasogastric aspirate (NGA), and seven (77.8%) of these also had an MTB positive Xpert result on stool. Additionally, MTB was detected in the stool but not on the NGA of two children. The SOS stool processing method makes use of the standard Xpert assay kit, without the need for additional supplies or equipment. The method can potentially be rolled out to any Xpert site, bringing a bacteriologically confirmed diagnosis of TB in children closer to the point of care.

BackgroundFecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) remains poorly documented in Africa. The objective of this study was to determine the prevalence of ESBL-PE fecal carriage in Chad.MethodsIn total, 200 fresh stool samples were collected from 100 healthy community volunteers and 100 hospitalized patients from January to March 2017. After screening using ESBL-selective agar plates and species identification by MALDI-TOF mass spectrometry, antibiotic susceptibility was tested using the disk diffusion method, and ESBL production confirmed with the double-disc synergy test. The different ESBL genes in potential ESBL-producing isolates were detected by PCR and double stranded DNA sequencing. Escherichia coli phylogenetic groups were determined using a PCR-based method.ResultsESBL-PE fecal carriage prevalence was 44.5% (51% among hospitalized patients vs 38% among healthy volunteers; p < 0.05). ESBL-producing isolates were mostly Escherichia coli (64/89) and Klebsiella pneumoniae (16/89). PCR and sequencing showed that 98.8% (87/89) of ESBL-PE harbored blaCTX-M genes: blaCTX-M-15 in 94.25% (82/87) and blaCTX-M-14 in 5.75% (5/87). Phylogroup determination by quadruplex PCR indicated that ESBL-producing E. coli isolates belonged to group A (n = 17; 27%), C (n = 17; 27%), B2 (n = 9; 14%), B1 (n = 8; 13%), D (n = 8; 13%), E (n = 1; 1.6%), and F (n = 1; 1.6%). The ST131 clone was identified in 100% (9/9) of E. coli B2 strains.ConclusionsThe high fecal carriage rate of ESBL-PE associated with CTX-M-15 in hospital and community settings of Chad highlights the risk for resistance transmission between non-pathogenic and pathogenic bacteria.