Usefulness of gastric aspirate for the diagnosis of smear-negative pulmonary tuberculosis.

INTRODUCTION: Gastric aspirate can be useful for the diagnosis of pulmonary tuberculosis (TB) in patients with smear-negative pulmonary TB or without sputum production. The gastric aspirate smear technique has low sensitivity, and a previous report demonstrated that no patient was diagnosed by only gastric aspirate analysis. However, some patients with TB have been negative on sputum examination but positive on gastric aspirate examination, and the incidence of such cases is uncertain. Therefore, this study investigated the usefulness of gastric aspirate in the diagnosis of pulmonary TB. METHODS: To analyze the diagnostic accuracy of gastric aspirate examination, the data of 513 patients with negative sputum smears or a lack of sputum production, including 203 patients with pulmonary TB (39.6%) and 93 patients with nontuberculous mycobacteriosis who underwent gastric aspiration at Fukujuji Hospital from January 2016 to March 2021, were collected retrospectively. RESULTS: The accuracy rates of gastric aspirate examination for the diagnosis of pulmonary TB were as follows: 21.2% sensitivity and 91.9% specificity for smear positivity, 55.8% sensitivity and 99.6% specificity for nucleic acid amplification test positivity, and 71.4% sensitivity and 100% specificity for culture positivity. Twenty-three patients (11.2%) were diagnosed by gastric aspirate examination alone. Among the 356 patients who underwent three repeated sputum examinations in addition to gastric aspirate examination, the cumulative diagnostic rate for the 3 mycobacterial examinations plus gastric aspirate examination was higher than that for only three sputum examinations. CONCLUSIONS: Gastric aspirate is useful for the diagnosis of TB in patients with smear-negative pulmonary TB or without sputum production.

Evaluation of Xpert MTB/RIF Ultra Assay for Diagnosis of Childhood Tuberculosis: a Multicenter Accuracy Study.

A multicenter study was performed to evaluate the value of testing gastric aspirate (GA) with Xpert MTB/RIF Ultra assay (Ultra) for childhood tuberculosis (TB) detection in China. In total, 129 children with active TB and 173 children without TB were enrolled. The sensitivity of Ultra in bacteriologically confirmed TB and probable TB cases was 87.5% (42/48) and 44.4% (36/81), respectively. The specificity of Ultra was high (99.4%, 172/173). When Ultra, culture, and acid-fast bacilli outcomes were integrated as a composite reference standard, the percentage of children with definite TB increased from 37.2% (48/129) to 67.4% (87/129). The sensitivity of Ultra is 80.0% (40/50) in children aged <4 years, which is significantly higher than that in older children (48.1%, 38/79) (P < 0.001). Ultra conducted using GA samples can provide faster results, allowing an early and accurate TB diagnosis, especially in younger children with difficulty producing sputum.

Predicting respiratory distress syndrome at birth using a fast test based on spectroscopy of gastric aspirates: 2. Clinical part.

AIM: To evaluate the accuracy of our new rapid point-of-care (POC) test for lung maturity. The method as we describe in an accompanying article was developed with the purpose of improving the outcome from respiratory distress syndrome (RDS). The test enables the delivery of surfactant in infants with immature lungs already at birth and ensures that infants with mature lungs are not treated unnecessarily. METHODS: Fresh gastric aspirate (GAS) was sampled at birth in a cohort of preterm infants with gestational ages ranging between 24 and 31 completed weeks for lung surfactant measurement as lecithin-sphingomyelin ratio (L/S). L/S was prospectively compared with RDS development. The clinical outcome was blinded for the investigators of L/S. The time for analysis was <15 minutes. RESULTS: GAS was obtained from 72 infants. Forty-four (61%) developed RDS. The cut-off for L/S was 3.05; predicting RDS with a sensitivity of 91% and specificity of 79%. CONCLUSION: The new improved spectroscopic L/S method of lung maturity on GAS has high sensitivity. The method is designed for use as a POC test at birth, and a spectroscopic prototype has been developed for bedside use. Clinical trials with this new lung maturity test are planned.

Predicting respiratory distress syndrome at birth using fast test based on spectroscopy of gastric aspirates. 1. Biochemical part.

AIM: To develop a fast bedside lung maturity test. METHODS: Gastric aspirates obtained from premature infants contain lamellar bodies, carrying lung surfactant. To estimate lung maturity, we isolated lamellar bodies from fresh gastric aspirates by centrifugation. Erythrocytes and other cells were lysed by adding water and discarded subsequently with the supernatant. Mid-infrared spectroscopy was then performed to measure the lung maturity as lecithin-sphingomyelin ratio. Lecithin was determined as dipalmitoylphosphatidylcholine, the most surface-active phospholipid. Algorithms to measure lecithin and sphingomyelin concentrations in fresh gastric aspirates were developed on aspirates from 140 premature infants. Each gastric aspirate sample was divided into two samples: one for mass spectrometry as reference and one for spectroscopy. Development of the algorithm is described in detail in Appendix S1. RESULTS: Gastric aspirates stored at 4-5°C avoid flocculation of proteins and phospholipids in contrast to when the aspirates were frozen and thawed. Omission of freezing and concentration of the lung surfactant by centrifugation combined with diminished influence of proteins improves the spectroscopic measurement of lecithin-sphingomyelin ratio. Measurement of lecithin-sphingomyelin ratio by the new method was performed within 10-15 minutes. CONCLUSION: We present a new fast bedside lung maturity test on fresh gastric aspirate for early targeted surfactant treatment.

Ultrasonography for nasogastric tube placement verification: an additional reference.

Nasogastric tube (NGT) insertion is a common procedure performed by community nurses, but verifying correct placement can be challenging due to the limitations of conventional methods. This study aimed to investigate the effectiveness of point-of-care ultrasonography (POCUS) for verifying NGT placement and to explore the feasibility of using this imaging modality as the first-line reference for NGT placement verification. The validity of the gastric aspirate pH test was also evaluated. This was a single-centre, retrospective, single-blind study using a convenience sample of patients who required NGT placement in home settings. POCUS was performed by a trained community nurse, and the pH test was performed after tube insertion. The results of the POCUS and pH test were compared. A total of 68 patients with a mean age of 82.13±9.43 years were included. The sensitivity and specificity were found to be 95.45% and 100%, respectively, for POCUS, and 90.91% and 100%, for the pH test. POCUS can provide accurate diagnostic imaging of nasogastric tube position and avoid X-ray controls. This imaging modality can complement pH testing in community settings where X-ray scans are not readily available.

Usefulness of Gastric Aspirate Culture for Diagnosing Congenital Immunodeficiency in an Infant with Fungal Pneumonia Caused by Rasamsonia piperina.

Chronic granulomatous disease (CGD) is a type of primary immunodeficiency disease, which increases susceptibility to recurrent bacterial and fungal infections. Sputum and bronchoalveolar lavage fluid are often obtained using bronchoscopy from adult patients for pathogenic diagnosis, although this approach is much more invasive for infants. We report the case of a 2-month-old boy with CGD, in which gastric aspirate culture was used to diagnose fungal pneumonia. Rasamsonia piperina was isolated from the gastric aspirate, and the patient was successfully treated with micafungin based on the drug susceptibility test results for the fungal isolate. The acid tolerance test revealed that R. piperina could grow at pH 2, indicating high acid resistance. Although we can only report our experience with a single case, gastric aspirate culture may be a useful tool for detecting fungal respiratory pathogens in children with primary immunodeficiency. Detecting these pathogens may help improve outcomes, as early diagnosis and appropriate treatment are extremely important for immunocompromised patients with respiratory infections.

Feasibility of the string test for tuberculosis diagnosis in children between 4 and 14 years old.

BACKGROUND: The enteric string test can be used to obtain a specimen for microbiological confirmation of tuberculosis in children, but it is not widely used for this. The aim of this analysis to evaluate this approach in children with tuberculosis symptoms. METHODS: We conducted a cross-sectional study to assess children's ability to complete the test (feasibility), and self-reported pain (tolerability). We examined caregivers' and children's willingness to repeat the procedure (acceptability) and described the diagnostic yield of cultures for diagnostic tools. We stratified estimates by age and compared metrics to those derived for gastric aspirate (GA). RESULTS: Among 148 children who attempted the string test, 34% successfully swallowed the capsule. Feasibility was higher among children aged 11-14 than in children 4-10 years (83% vs 22% respectively, p < 0.0001). The string test was better tolerated than GA in both age groups; however, guardians and older children reported higher rates of willingness to repeat GA than the string test (86% vs. 58% in children; 100% vs. 83% in guardians). In 9 children with a positive sputum culture, 6 had a positive string culture. The one children with a positive gastric aspirate culture also had a positive string culture. CONCLUSION: Although the string test was generally tolerable and accepted by children and caregivers; feasibility in young children was low. Reducing the capsule size may improve test success rates in younger children.

The Incremental Value of Repeated Induced Sputum and Gastric Aspirate Samples for the Diagnosis of Pulmonary Tuberculosis in Young Children With Acute Community-Acquired Pneumonia.

BACKGROUND.: Mycobacterium tuberculosis (Mtb) contributes to the pathogenesis of childhood acute community-acquired pneumonia in settings with a high tuberculosis burden. The incremental value of a repeated induced sputum (IS) sample, compared with a single IS or gastric aspirate (GA) sample, is not well known. METHODS.: Two IS samples were obtained for Mtb culture from children enrolled as cases in the Pneumonia Etiology Research for Child Health (PERCH) study in South Africa. Nonstudy attending physicians requested GA if pulmonary tuberculosis was clinically suspected. We compared the Mtb yield of 2 IS samples to that of 1 IS sample and GA samples. RESULTS: . Twenty-seven (3.0%) culture-confirmed pulmonary tuberculosis cases were identified among 906 children investigated with IS and GA samples for Mtb. Results from 2 IS samples were available for 719 children (79.4%). Of 12 culture-confirmed pulmonary tuberculosis cases identified among children with ≥2 IS samples, 4 (33.3%) were negative at the first IS sample. In head-to-head comparisons among children with both GA and IS samples collected, the yield of 1 GA sample (8 of 427; 1.9%) was similar to that of 1 IS sample (5 of 427, 1.2%), and the yield of 2 GA samples (10 of 300; 3.3%) was similar to that of 2 IS samples (5 of 300; 1.7%). IS samples identified 8 (42.1%) of the 19 culture-confirmed pulmonary tuberculosis cases that were identified through submission of IS and GA samples. CONCLUSIONS.: A single IS sample underestimated the presence of Mtb in children hospitalized with severe or very severe pneumonia. Detection of Mtb is enhanced by combining 2 IS with GA sample collections in young children with acute severe pneumonia.

Rapid test for lung maturity, based on spectroscopy of gastric aspirate, predicted respiratory distress syndrome with high sensitivity.

AIM: Respiratory distress syndrome (RDS) is a major cause of mortality and morbidity in premature infants. By the time symptoms appear, it may already be too late to prevent a severe course, with bronchopulmonary dysplasia or mortality. We aimed to develop a rapid test of lung maturity for targeting surfactant supplementation. METHODS: Concentrations of the most surface-active lung phospholipid dipalmitoylphosphatidylcholine and sphingomyelin in gastric aspirates from premature infants were measured by mass spectrometry and expressed as the lecithin/sphingomyelin ratio (L/S). The same aspirates were analysed with mid-infrared spectroscopy. Subsequently, L/S was measured in gastric aspirates and oropharyngeal secretions from another group of premature infants using spectroscopy and the results were compared with RDS development. The 10-minute analysis required 10 µL of aspirate. RESULTS: An L/S algorithm was developed based on 89 aspirates. Subsequently, gastric aspirates were sampled in 136 infants of 24-31 weeks of gestation and 61 (45%) developed RDS. The cut-off value of L/S was 2.2, sensitivity was 92%, and specificity was 73%. In 59 cases, the oropharyngeal secretions had less valid L/S than gastric aspirate results. CONCLUSION: Our rapid test for lung maturity, based on spectroscopy of gastric aspirate, predicted RDS with high sensitivity.

Feasibility and utility of a combined nasogastric-tube-and-string-test device for bacteriologic confirmation of pulmonary tuberculosis in young children.

For microbiological confirmation of pediatric pulmonary tuberculosis (PTB), gastric aspirates (GA) are often operationally unfeasible without hospitalization, and the encapsulated orogastric string test is not easily swallowed in young children. The Combined-NasoGastric-Tube-and-String-Test (CNGTST) enables dual collection of GA and string specimens. In a prospective cohort study in Kenya, we examined its feasibility in children under five with presumptive PTB and compared the bacteriological yield of string to GA. Paired GA and string samples were successfully collected in 95.6 % (281/294) of children. Mycobacterium tuberculosis was isolated from 7.0 % (38/541) of GA and 4.3 % (23/541) of string samples, diagnosing 8.2 % (23/281) of children using GA and 5.3 % (15/281) using string. The CNGTST was feasible in nearly all children. Yield from string was two-thirds that of GA despite a half-hour median dwelling time. In settings where the feasibility of hospitalisation for GA is uncertain, the string component can be used to confirm PTB.

Diagnostic Approaches to Helicobacter pylori: A Comparative Study of Detection in Gastric Biopsy and Aspirates.

Background Helicobacter pylori is one of the most common bacterial pathogens in humans. It is a microaerophilic bacteria with multiple unipolar flagella. It is associated with the development of various lesions like chronic gastritis, gastric ulcers, adenocarcinoma, and mucosa-associated lymphomas. The aim of this study was a comparative evaluation of the rapid urease test (RUT) and polymerase chain reaction (PCR) in gastric biopsy and aspirates for the detection of H. pylori infection and to further determine the sensitivity and specificity of RUT and PCR. Method Endoscopic guided biopsy tissue and gastric aspirate specimens were collected from 110 patients with symptoms like gastritis, dyspepsia, etc., and subjected to RUT and PCR for detection of H. pylori infection. Results A total of 110 samples, including both biopsy tissue (77) and gastric aspirate (33) were subjected to RUT and PCR. RUT for biopsy tissue showed the highest sensitivity (97.18%), compared to gastric aspirate (78.94%). Comparing RUT with PCR, the sensitivity and specificity of PCR were 93.33% and 90.0%, respectively. The positive predictive value (PPV) of PCR was 97.67%, the negative predictive value (NPV) was 75.0%, and the accuracy was 92.73%. Conclusion The present study showed that RUT is a rapid and accurate invasive test for the detection of Helicobacter pylori infection in biopsy tissue as compared to gastric aspirate specimens, which are more sensitive to PCR. The study also showed that biopsy tissue was found to be a superior specimen for the detection of Helicobacter pylori as compared to gastric aspirate.

Diagnostic Utility of Cartridge-Based Nucleic Acid Amplification Test (CBNAAT) on Induced Sputum Versus Gastric Aspirate Samples for the Diagnosis of Paediatric Pulmonary Tuberculosis.

BACKGROUND: Tuberculosis (TB) in children is neglected, mainly due to a lack of sensitive diagnostic tools. Paediatric TB is now a global priority. More paediatric TB cases are being recorded as a result of the introduction of Xpert® Mycobacterium tuberculosis (MTB)/rifampicin (RIF) (Cepheid Inc., Sunnyvale, USA). This study was undertaken to evaluate the performance of Xpert MTB/RIF in the diagnosis of pulmonary TB in children. METHODS: We recruited 70 paediatric patients with probable pulmonary TB and their gastric aspirate (GA), and induced sputum (IS) samples were collected between January 2021 and June 2022 in Saifai, Etawah, Uttar Pradesh, at the Microbiology Department of the Uttar Pradesh University of Medical Sciences (U.P.U.M.S.). All samples were subjected to smear examination, Bacterial Activation of Continuous Temperature and Environmental Control - Mycobacterial Growth Indicator Tube (BACTEC-MGIT) culture, and Xpert MTB/RIF. RESULTS:  The specimens included 70 GAs and 70 IS samples. The total number of specimens were 140 and we collected GA as well as IS from each of the patient enrolled in the study. When compared to microscopy, GeneXpert provides a quicker and earlier detection of paediatric TB. The sensitivity of the cartridge-based nucleic acid amplification test (CBNAAT) against mycobacterial growth indicator tube (MGIT) was 75.0% for GA samples and 63.64% for IS samples. CONCLUSION: Paediatric TB, owing to its paucibacillary nature and difficulty in the collection of samples, makes the diagnosis difficult by conventional methods. Our study shows that smear and culture yield in GA samples are superior to those of IS samples and the sensitivity of Xpert MTB/RIF assay is also significantly different in GA and IS samples, but a combination of GA and IS yielded the best results.

Effect of time, temperature and pH on Mycobacterium tuberculosis culture positivity of gastric aspirate: An experimental study.

BACKGROUND: The culture of gastric aspirate (GA) has been used for bacteriological confirmation of pulmonary tuberculosis in children and patients who are unable to expectorate. Sodium bicarbonate neutralization of gastric aspirates is commonly recommended to increase culture positivity. We aim to study Mycobacterium tuberculosis (MTB) culture positivity of GA collected from confirmed case of pulmonary tuberculosis after storing it at different temperature, pH & time. METHODS: GA specimens from 865 patients of either sex predominately non-expectorating children/adults with suspected pulmonary TB were collected. Gastric lavage was performed in the morning after an overnight fasting (at least 6hrs fasting). The GA specimens were tested by CBNAAT (GeneXpert) and AFB microscopy & those who were positive on CBNAAT were further processed with MTB culture on Growth Indicator Tube (MGIT™) culture. pH neutralized and non-neutralized CBNAAT positive GA specimens were culture within 2 hours of collection and 24 hours after storage at 4 °C & room temperature. RESULTS: MTB was detected in 6.8% of collected GA specimens by CBNAAT. Culture positivity of neutralized GA specimens when processed within 2 hours of collection, was higher compared to paired non-neutralized GA specimens. Neutralized GA specimens had higher contamination rate than non-neutralized GA specimens. Storage of GA specimens at $Deg C had better culture yield than those stored at room temperature. CONCLUSION: Early neutralization of acid in Gastric aspirate (GA) is essential for better culture positivity of M. tuberculosis (MTB). If there is a delay in processing GA, it should be kept at 4 °C after neutralization; however, positivity decreases with time.

A Novel Cross-Priming Amplification-Based Assay for Tuberculosis Diagnosis in Children Using Gastric Aspirate.

Low detection rates of Mycobacterium tuberculosis (MTB) by culture and smear microscopy prevent early diagnosis of tuberculosis (TB) in children. Therefore, developing rapid and accurate diagnostic techniques are critical to achieving the global aim of minimizing childhood TB. The present study was performed to evaluate the diagnostic effectiveness of the novel cross-priming amplification-based EasyNAT MTB complex assay (EasyNAT) in childhood TB. Five hundred and six children with suspected TB were enrolled from January 2018 to October 2021. Gastric aspirate (GA) samples were tested by bacterial culture, acid-fast bacillus microscopy, EasyNAT, Xpert MTB/RIF (Xpert), or Xpert MTB/RIF Ultra (Xpert Ultra). Among 239 children simultaneously tested by EasyNAT and Xpert methods, both assays showed similar sensitivities in total active TB cases [22.6% (31/137) vs. 26.3% (36/137), p = 0.441] and in bacteriologically confirmed TB cases [both 60.0% (9/15)]. The two assays presented similar specificities of 98.0% (100/102) and 99.0% (101/102), respectively (p = 1.000). Among 267 children who were simultaneously tested with EasyNAT and Xpert Ultra, Xpert Ultra demonstrated higher sensitivity than EasyNAT in total active TB cases [50.9% (89/175) vs. 30.3% (53/175), p < 0.001]. EasyNAT and Xpert Ultra yielded similar specificities, at 97.8% (90/92) and 100.0% (92/92), respectively (p = 0.155). These findings indicated that Xpert Ultra was superior to EasyNAT despite its higher cost and EasyNAT was not inferior to Xpert in the diagnosis of childhood TB using GA samples. EasyNAT may therefore be a suitable alternative diagnostic method for childhood TB based on its cost-effectiveness, speed, and accuracy.

Effect of Neutralization of Gastric Aspirate on culture yield of mycobacterium tuberculosis in children with pulmonary tuberculosis.

INTRODUCTION: Conventionally gastric aspirates are neutralized with sodium bicarbonate to improve the culture yield of MTB. However, only limited data is there to support this practice. The aim of this study was to compare the contamination rate, culture yield and time to detection of Mycobacterium tuberculosis (MTB) in neutralized and non-neutralized gastric aspirate samples and report the drug resistance. MATERIALS AND METHODS: A total of 336 neutralized and non-neutralized gastric aspirate samples were simultaneously cultured by both LJ culture and MGIT 960 to compare the difference in isolation rate, time to detection and contamination rate. First line drug susceptibility testing was performed using MGIT 960 SIRE kit. RESULTS: MTB was isolated from 8.6% (29/336) of GA samples by one or more of the culture methods. The isolation rate of MTB from neutralized and non-neutralized GA samples by combined LJ and MGIT 960 culture was 7.1% (24/336) and 6.8% (23/336), respectively. Both of them detected 18 MTB isolates in common. However, the neutralized and non-neutralized GA samples detected additional 6 and 5 MTB isolates, respectively. The mean time to detection of MTB were similar. In MGIT 960 culture, contamination rate of non-neutralized samples (17%) was significantly lower when compared to neutralized samples (21.1%) (P = 0.044). Drug susceptibility testing of MTB isolates revealed that, out of 26 isolates, 2 were resistant to ethambutol, one each was resistant to isoniazid and rifampicin. CONCLUSION: The findings of this study suggest that non-neutralized samples should be routinely processed in addition to the neutralized samples for optimum isolation of MTB from gastric aspirate samples.

Diagnosis of Tuberculosis Using Gastric Aspirates in Pediatric Patients in Haiti.

BACKGROUND: We aimed to determine whether the Xpert MTB/RIF (Xpert) assay is a useful adjunct to culture for the rapid diagnosis of tuberculosis (TB) using gastric lavage aspirates (GLAs) in children aged < 5 years. METHODS: We reviewed the yield from diagnostic modalities in children suspected of having TB followed at an infectious disease research and treatment center in Port-au-Prince, Haiti, from 2011 to 2016. RESULTS: In 187 children clinically diagnosed with TB, a microbiologic diagnosis could be established in 40 (21%). Cultures, Xpert, and smears were positive in 30 (19%), 28 (17%), and 3 (1.6%) children, respectively. Ten cases that would not have been diagnosed by culture alone were found by the use of the Xpert assay. Collecting 2 GLA samples optimized microbiologic yield. CONCLUSIONS: In GLAs, Xpert increased the yield of microbiologically documented cases by 33%. Additionally, the rapidity of diagnosis potentially makes Xpert a valuable adjunct in initiating treatment for TB in children. Smear microscopy has low sensitivity in GLA and did not add to the documented cases. Our findings also highlight the low rate of microbiologic confirmation of clinically diagnosed TB.

From Mum to Bum: An Observational Study Protocol to Follow Digestion of Human Milk Oligosaccharides and Glycoproteins from Mother to Preterm Infant.

The nutritional requirements of preterm infants are challenging to meet in neonatal care, yet crucial for their growth, development and health. Aberrant maturation of the gastrointestinal tract and the microbiota could affect the digestion of human milk and its nutritional value considerably. Therefore, the main objective of the proposed research is to investigate how the intestinal microbiota of preterm and full-term infants differ in their ability to extract energy and nutrients from oligosaccharides and glycoproteins in human milk. This pilot study will be an observational, single-center study performed at the Neonatal Intensive Care Unit at Isala Women and Children's Hospital (Zwolle, The Netherlands). A cohort of thirty mother-infant pairs (preterm ≤30 weeks of gestation, n = 15; full-term 37-42 weeks of gestation, n = 15) will be followed during the first six postnatal weeks with follow-up at three- and six-months postnatal age. We will collect human milk of all mothers, gastric aspirates of preterm infants and fecal samples of all infants. A combination of 16S rRNA amplicon sequencing, proteomics, peptidomics, carbohydrate analysis and calorimetric measurements will be performed. The role of the microbiota in infant growth and development is often overlooked yet offers opportunities to advance neonatal care. The 'From Mum to Bum' study is the first study in which the effect of a preterm gut microbiota composition on its metabolic capacity and subsequent infant growth and development is investigated. By collecting human milk of all mothers, gastric aspirates of preterm infants and fecal samples of all infants at each timepoint, we can follow digestion of human milk from the breast of the mother throughout the gastrointestinal tract of the infant, or 'From Mum to Bum'.

Microbiological Testing of Gastric Aspirate Improves the Diagnosis of Pulmonary Tuberculosis in Unconscious Adults with TB Meningitis.

Conventional sputum collection for TB diagnosis is difficult in TB meningitis patients since most of them are admitted with decreased consciousness. It is assumed that unconscious patients swallow their sputum; therefore, gastric aspiration can replace sputum collection in unconscious patients. A prospective study was conducted to see whether examining gastric aspirate could increase the diagnosis certainty of pulmonary TB in such subjects. The inclusion criteria were age 18-60 years, decreased level of consciousness, and use of a nasogastric tube. Subjects who had taken antituberculosis drugs for more than 3 days were excluded. Gastric lavage was performed in the morning after an overnight fast. Specimens were examined for direct smear, culture, and rapid molecular testing. Demographic, clinical, chest X-ray, and laboratory data were also recorded. During the study period, 31 subjects were available. The positivity rates for microbiological tests were 19.3%, 41.9%, and 48.4% for smear, culture, and rapid molecular testing, respectively. All positive smears were confirmed by either culture or rapid molecular testing. Gastric lavage can be considered a tool for improving extraneural TB diagnosis in unconscious patients.

In Vitro Gene Transcription of Listeria monocytogenes after Exposure to Human Gastric and Duodenal Aspirates.

The aim of the present study was to assess, for the first time to our knowledge, Listeria monocytogenes CFU changes, as well as to determine the transcription of key virulence genes, namely, sigB, prfA, hly, plcA, plcB, inlA, inlB, inlC, inlJ, inlP, and lmo2672 after in vitro exposure to human gastric and duodenal aspirates. Furthermore, investigations of the potential correlation between CFU changes and gene regulation with factors influencing gastric (proton pump inhibitor intake and presence of gastric atrophy) and duodenal pH were the secondary study aims. Gastric and duodenal fluids that were collected from 25 individuals undergoing upper gastrointestinal endoscopy were inoculated with L. monocytogenes serotype 4b strain LQC 15257 at 9 log CFU·mL-1 and incubated at 37°C for 100 min and 2 h, respectively, with the time corresponding to the actual exposure time to gastric and duodenal fluids in the human gastrointestinal tract. Sampling was performed upon gastric fluid inoculation, after incubation of the inoculated gastric fluids, upon pathogen resuspension in duodenal fluids and after incubation of the inoculated duodenal fluids. L. monocytogenes CFU changes were assessed by colony counting, as well as reverse transcription quantitative PCR by using inlB as a target. Gene transcription was assessed by reverse transcription quantitative PCR. In 56% of the cases, reduction of the pathogen CFU occurred immediately after exposure to gastric aspirate. Upregulation of hly and inlC was observed in 52 and 58% of the cases, respectively. On the contrary, no upregulation or downregulation was noticed regarding sigB, prfA, plcA, plcB, inlA, inlB, inlJ, inlP, and lmo2672. In addition, sigB and plcA transcription was positively and negatively associated, respectively, with an increase of the pH value, and inlA transcription was negatively associated with the presence of gastric atrophy. Finally, a positive correlation between the transcriptomic responses of plcB, inlA, inlB, inlC, inlJ, inlP, and lmo2672 was detected. This study revealed that the CFU of the pathogen was negatively affected after exposure to human gastroduodenal aspirates, as well as significant correlations between the characteristics of the aspirates with the virulence potential of the pathogen.

The clinical diagnostic value of Xpert MTB/RIF for the detection of Mycobacterium tuberculosis in gastric aspirates.

BACKGROUND: At present, the infection and prevalence rates of tuberculosis (TB) are still high in worldwide. The Xpert MTB/RIF technology has improved the diagnosis speed of Mycobacterium tuberculosis (MTB) and facilitated the rapid treatment of TB patients. METHODS: We searched experimental data derived from Xpert MTB/RIF for detecting MTB in gastric aspirates in PubMed, Embase, Web Of Science, and the Cochrane Library databases between January 2012 to April 2019. A summary receiver operating characteristic curve (SROC curve) was used to analyze the pooled sensitivity, pooled specificity, PLR, NLR, and DOR for determining the accuracy of the test. RESULTS: Our database search resulted in 10 relevant articles. The pooled sensitivity of Xpert MTB/RIF for detecting TB in GA was 86% (95% CI, 83-89%), and I2 = 93.4%. The pooled specificity was 92% (95% CI, 90-93%) and I2 = 97.8%. In addition, the positive LR was 12.12 (95% CI, 5.60-26.21), negative LR was 0.20 (95% CI, 0.11-0.36), and the diagnostic odds ratio (DOR) was 147.04 (95% CI, 37.20-581.19). Using the SROC curve, the AUC was 0.9730 and Q* was 0.9248 (SE = 0.0261). The publication bias was P=0.517 (P>0.05). CONCLUSIONS: The Xpert MTB/RIF for detecting MTB in gastric aspirates was highly accurate. In addition, we observed that the publication bias in the present study was low. Hence, the Xpert MTB/RIF technology is highly accurate and has the advantage of rapid testing for MTB in clinical samples.