False-Negative 68 Ga-FAPI PET/CT in Pediatric Thyroid Medullary Carcinoma Seen With 68 Ga-DOTATOC PET/CT and 18 F-FDG PET/CT.

ABSTRACT: In adults, 68 Ga-FAP inhibitor ( 68 Ga-FAPI) PET/CT outperforms 68 Ga-radiolabeled somatostatin analog peptides ( 68 Ga PET/CT) and 18 F-FDG PET/CT in detecting thyroid lesions. This is the case of a 13-year-old boy newly diagnosed with medullary thyroid cancer with high calcitonin level. 68 Ga PET/CT revealed the presence of only a primary thyroid lesion. Proven to be superior in detecting metastasis, 68 Ga-FAPI PET/CT was performed. The results came out negative for primary and potential metastatic lesions. This case sheds shed light on false-negatives reported in 68 Ga-FAPI PET/CT scans in pediatric patients, emphasizing the need for alternate radiotracers when a negative study is met.

Interferon-Gamma Release Assay Combined with Renal Indicators to Reduce the False-Negativity of Latent Tuberculosis Infection in End-Stage Renal Disease with Hemodialysis Patients.

BACKGROUND: Tuberculosis (TB) is still the main cause of mortality due to a single transfectant, Mycobacterium tuberculosis (MTB). Latent tuberculosis infection (LTBI) is a condition characterized by the presence of tuberculosis (TB) that is not clinically apparent but nonetheless shows a sustained response to MTB. Presently, tuberculin skin test (TST) and interferon gamma (IFN-γ) release assays (IGRAs) are mainly used to detect LTBI via cell-mediated immunity of T-cells. For people with end-stage renal disease (ESRD), the diagnosis of patients infected with MTB is difficult because of T-cell dysfunction. To get more accurate diagnosis results of LTBI, it must compensate for the deficiency of IGRA tests. METHODS: Sixty-seven hemodialysis (HD) patients and 96 non-HD patients were enrolled in this study and the study population is continuously included. IFN-γ levels were measured by the QuantiFERON-TB Gold In-Tube (QFT-GIT) test. Kidney function indicators, blood urea nitrogen (BUN), serum creatinine (Cr), and estimated glomerular filtration rate (eGFR) were used to compensate for the declined IFN-γ levels in the IGRA test. RESULTS: In individuals who were previously undetected, the results of compensation with serum Cr increased by 10.81%, allowing for about 28% more detection, and compensation with eGFR increased by 5.41%, allowing for approximately 14% more detectable potential among them and employing both of them could enhance the prior shortcomings of IGRA tests. when both are used, the maximum compensation results show a sensitivity increase rate of 8.81%, and approximately 23% of patients who were previously undetectable may be found. CONCLUSION: Therefore, the renal function markers which are routine tests for HD patients to compensate for the deficiency of IGRA tests could increase the accuracy of LTBI diagnosis.

A case of disseminated cryptococcosis with abdominal involvement due to Cryptococcus neoformans species complex in a Ragdoll cat and false-negative cryptococcal antigen lateral flow tests due to the postzone phenomenon.

Although cryptococcosis is the most common systemic fungal disease of cats, abdominal involvement is rarely reported. The pathogenesis of cryptococcosis usually involves sinonasal colonisation, followed by tissue invasion and sinonasal infection, with possible subsequent spread to the lungs and/or direct extension into the central nervous system (CNS), for example, via the cribriform plate. Further haematogenous spread can occur to any tissue, including skin and the CNS. This report describes a case of disseminated cryptococcosis due to Cryptococcus neoformans species complex in a 13-year-old cat, the fourth documented Australian feline case with abdominal involvement. The cat presented with a chronic history of upper respiratory disease that progressed to severe lethargy and anorexia. An autopsy revealed striking peritonitis with multifocal abdominal involvement affecting the liver, spleen, adrenal glands, kidneys, pancreas and mesentery. Cryptococcal organisms were also observed in organs within the thoracic cavity, sinonasal tissues and the CNS. Testing of abdominal fluid and serum for cryptococcal antigen using a commercially available lateral flow assay using neat fluid specimen initially tested false-negative. However, after dilution of the sample to 1:64, a positive result was obtained, confirming a postzone phenomenon. Taken together, the collective findings were indicative of widely disseminated cryptococcosis due to Cryptococcus neoformans with atypical involvement of the abdominal cavity.

Long-term follow-up of a series of 24 congenital CMV-infected babies with false negative amniocentesis.

BACKGROUND: Congenital CMV infection is the most common congenital infection worldwide and a major cause of neurological impairment and sensorineural hearing loss. Fetal CMV infection is confirmed by a positive PCR test in the amniotic fluid (amniocentesis performed after 18-20 weeks of gestation and at least 8 weeks after maternal infection). However, despite a negative antenatal CMV PCR result, some newborns can be tested positive at birth. Although not widely documented, the prognosis for these babies appears to be good. OBJECTIVES: The aim of this study is to evaluate the long-term prognosis of fetuses with a false-negative AFS for cCMV, with a minimum follow-up period of 6 years. STUDY DESIGN: This is a retrospective cohort study of false-negative amniocentesis reported at the CUB-Hôpital Erasme and Hôpital CHIREC in Brussels between 1985 and 2017. RESULTS: Of the 712 negative CMV PCR amniocenteses, 24 had a CMV PCR positive at birth. The false negative rate was 8.6 %. Of the 24 cases, 9 primary maternal infections occurred in the first trimester, 14 in the second trimester and 1 in the third trimester. Among the 24 children, 2 had symptoms at birth (hyperbilirubinemia and left paraventricular cysts), but all had normal follow-up (minimum 4 years, mean 16,6 years). DISCUSSION: Only 2 cases could be explained by early amniocentesis. Among the others, the false-negative results could be attributed to a low viral load, a delayed infection or, less likely, to a sample degradation. CONCLUSION: Despite the false-negative results, all 24 children had a normal long-term follow-up.

Heparin-mediated PCR interference in SARS-CoV-2 assays and subsequent reversal with heparinase I.

Heparin is postulated to block the interaction of SARS-CoV-2 with highly glycosylated proteins which are critical for binding the angiotensin-converting enzyme 2 (ACE2), an essential mechanism for host-cell entry and viral replication. Intranasal heparin is under investigation for use as a SARS-CoV-2 preventative in the IntraNasal Heparin Trial (INHERIT, NCT05204550). Heparin directly interferes with real-time quantitative polymerase chain reaction (RT-qPCR), the gold standard for SARS-CoV-2 detection. This study aimed to investigate the magnitude of heparin interference across various clinical laboratory testing platforms, and the reversal of any interference by degradation of heparin using the heparinase I enzyme in nasopharyngeal swab (NP) samples for SARS-CoV-2 analysis by RT-qPCR. Heparin-mediated PCR interference was evident at heparin concentrations as low as 10 IU/mL across all platforms tested, with the exclusion of the Hologic Panther Aptima SARS-CoV-2 assay. Rates of false negative or invalid results increased with increasing heparin concentrations on all platforms, except the Hologic Panther Aptima and Roche Cobas LIAT. Heparinase I reversed heparin-mediated PCR inhibition across in all samples tested, except those with initial Ct values >35. Our study shows that the use of heparin-containing nasal sprays interferes with the detection of SARS-CoV-2 in NP swab samples by RT-qPCR, a phenomenon that is not well recognised in the literature. Furthermore, this study has also demonstrated that heparin-mediated PCR inhibition can be prevented through heparinase I treatment, demonstrating restoration of clinically significant results with Ct values <35.

Clipping a Positive Lymph Node Improves Accuracy of Nodal Staging After Neoadjuvant Chemotherapy for Breast Cancer Patients, but Does It Drive Management Changes?

BACKGROUND: Sentinel lymph node (SLN) biopsy for cN+ breast cancer patients after neoadjuvant chemotherapy (NAC) is controversial because the false-negative rate (FNR) is high. Identification of three or more SLNs with a dual tracer improves these results, and inclusion of a clipped lymph node (CLN) (targeted axillary dissection [TAD]) may be even more effective. METHODS: A retrospective, single-institution analysis of consecutive cN+ patients undergoing NAC from 2019 to 2021 was performed. Patients routinely underwent placement of a clip in the positive lymph node before NAC, and TAD was performed after completion of therapy. RESULTS: The study analyzed 73 patients, and the identification rate for CLN was 98.6% (72/73). A complete response in the lymph nodes was achieved for 43 (59%) of the 73 patients. Overall, the CLN was not a SLN in 18 (25%) of 73 cases, and for women who had one or two and those who had three or more SLNs identified, this occurred in 11 (32%) and 7 (21%) of 34 cases, respectively. Failure of SLN or TAD to identify a positive residual lymph node status after NAC occurred in 10 (15%) of 69 and 2 (3%) of 73 cases, respectively (p = 0.01). In four cases, a SLN was not retrieved (5.5%), and two of these cases had a positive CLN. In three cases, the CLN was the only positive node and did not match with a SLN, directing lymphadenectomy and oncologic management change in two cases. Therefore, 7 (10%) of 73 cases had a change in surgical or oncologic management with TAD. CONCLUSIONS: For a conservative axillary treatment in this setting, TAD is an effective method. It is more accurate than SLN alone and allows management changes. Further studies are warranted.

The features associated with mammography-occult MRI-detected newly diagnosed breast cancer analysed by comparing machine learning models with a logistic regression model.

PURPOSE: To compare machine learning (ML) models with logistic regression model in order to identify the optimal factors associated with mammography-occult (i.e. false-negative mammographic findings) magnetic resonance imaging (MRI)-detected newly diagnosed breast cancer (BC). MATERIAL AND METHODS: The present single-centre retrospective study included consecutive women with BC who underwent mammography and MRI (no more than 45 days apart) for breast cancer between January 2018 and May 2023. Various ML algorithms and binary logistic regression analysis were utilized to extract features linked to mammography-occult BC. These features were subsequently employed to create different models. The predictive value of these models was assessed using receiver operating characteristic curve analysis. RESULTS: This study included 1957 malignant lesions from 1914 patients, with an average age of 51.64 ± 9.92 years and a range of 20-86 years. Among these lesions, there were 485 mammography-occult BCs. The optimal features of mammography-occult BC included calcification status, tumour size, mammographic density, age, lesion enhancement type on MRI, and histological type. Among the different ML models (ANN, L1-LR, RF, and SVM) and the LR-based combined model, the ANN model with RF features was found to be the optimal model. It demonstrated the best discriminative performance in predicting mammography false- negative findings, with an AUC of 0.912, an accuracy of 86.90%, a sensitivity of 85.85%, and a specificity of 84.18%. CONCLUSION: Mammography-occult MRI-detected breast cancers have features that should be considered when performing breast MRI to improve the detection rate for breast cancer and aid in clinician management.

Accuracy of sentinel lymph node biopsy in male breast cancer: Systematic review and meta-analysis.

BACKGROUND: Sentinel lymph node biopsy (SLNB) is commonly used in the surgical management of male breast cancer. Contrary to female breast cancer, limited data exist about its performance in male breast cancer. The objective of this systematic review and meta-analysis was to evaluate the SLNB accuracy in male breast cancer. METHODS: MEDLINE, EMBASE, Web of Science and The Cochrane Library were searched from January 1995 to April 2023 for studies evaluating the SLNB identification rate and false-negative rate in male breast cancer with negative preoperative axillary evaluation and primary surgery. For SLNB false-negative rate, the gold standard was the histology of axillary lymph node dissection (ALDN). Methodological quality was assessed by using the QUADAS-2 tool. Pooled estimates of the SLNB identification rate and false-negative rate were calculated. Heterogeneity of the pooled studies was evaluated using I2 index. RESULTS: A total of 12 retrospective studies were included. The 12 studies that reported the SLNB identification rate gathered a total of 164 patients; the 5 studies that reported the SLNB false-negative rate gathered a total of 50 patients with a systematic ALND. The pooled estimate of the SLNB identification rate was 99.0%. The SLNB false-negative rates were 0% in the 5 included studies and consequently so as the pooled estimate of the false-negative rate with no heterogeneity. CONCLUSION: SLNB for male breast cancer, following negative preoperative axillary assessment and primary surgery, appears feasible, consistent, and effective. Our research supports conducting immediate SLNB histological evaluation to facilitate prompt ALND in case of positive results.

False negative breast cancers on imaging and associated risk factors: a single institution six-year analysis.

PURPOSE: Mitigating false negative imaging studies remains an important issue given its association with worse morbidity and mortality in patients with breast cancer. We aimed to identify risk factors that predispose to false negative breast imaging exams. METHODS: In an IRB-approved, HIPAA compliant retrospective study, we identified all patients who were diagnosed with breast cancer within 365 days of a negative imaging study assessed as BI-RADS 1-3 between January 1, 2014 and January 31, 2020. A matched cohort based on mammographic breast density was created from randomly selected studies with BI-RADS 4-5 designation that yielded breast cancer at pathology within the same time frame. Patient and cancer characteristics, prior personal history of breast cancer and gene mutation status were collected from patient charts. Pearson chi-squared and Student's t-test on two independent groups with significance at < 0.05 was used for statistical analysis. RESULTS: We identified 155 false negative studies of 129 missed cancers and 128 breast density matched true positive cancers. False negative studies were screening mammograms in 57.42% (89/155), diagnostic mammograms in 29.68% (46/155), ultrasounds in 6.45% (10/155) and MRIs in 6.45% (10/155). Rates of personal (41.09% vs. 18.75%, p < 0.001) and family history of breast cancer (68.22% vs. 49.21%, p = 0.002) were higher in the false negative cohort and remained significant when asymptomatic MRI-detected cancers were removed. CONCLUSION: Our findings suggest that supplemental screening may be useful in breast cancer survivors.

Sensitivity and specificity of SS-OCT for detecting macular pathologies vs SD-OCT.

PURPOSE: To evaluate the sensitivity and specificity of swept-source optical coherence tomography (SS-OCT) biometer compared with the gold standard spectral-domain optical coherence tomography (SD-OCT) for detecting macular pathology in patients with cataract. SETTING: Eye Centers of Tennessee, Crossville, TN. DESIGN: Prospective, cross-sectional, observational, examiner-masked. METHODS: The study included 132 participants aged 50 years and older, who underwent precataract surgery work-up. All participants underwent fixation check retinal scans using SS-OCT biometer (IOLMaster 700) as well as full macular scans using Cirrus SD-OCT. 3 independent masked examiners evaluated the scans if they were normal or had a suspected pathology. Different measures of diagnostic accuracy were calculated for 3 examiners. RESULTS: True positive rate (sensitivity) ranged from 71.1% (32/45) to 79.2% (42/53), and false negative rate was between 20.8% (11/53) and 28.9% (13/45) for the 3 examiners. True negative rate (specificity) ranged from 86.8% (59/68) to 94.1% (64/68), and false positive rate was between 5.9 (4/68) and 13.2% (9/68). The fitted receiver operating characteristic area ranged from 0.83 to 0.95. CONCLUSIONS: Using retinal SS-OCT biometer scans as a replacement of the dedicated macular SD-OCT for screening or diagnosing macular health would not be appropriate because of its low sensitivity. SS-OCT biometer may potentially fail to identify approximately one-fourth of patients who actually have the disease. Therefore, the final decision on macular health should be based on the gold standard SD-OCT scans. When full macular SD-OCT scans are not accessible, the limited retinal scan information from SS-OCT biometer may still provide useful insights into the macular health.

The Utility of ACR TI-RADS in Predicting False-Negative Fine Needle Aspiration for Thyroid Cancer.

BACKGROUND: Thyroid nodule fine needle aspiration (FNA) biopsies are associated with a low false-negative rate. There is limited data regarding the predictive value of American College of Radiology Thyroid Imaging Reporting and Data System for false-negative FNA. METHODS: This single-center retrospective study evaluated 119 patients who underwent thyroidectomy. The association of TR category, along with other clinical variables, with false-negative FNA was evaluated. RESULTS: The overall false-negative rate of FNA was 10.8% (n = 9). False-negative FNAs were associated with younger age (mean 42 years vs 50.6 years, P = .04), larger nodule size (mean 4.4 cm vs 3.2 cm, P = .03), and a lower TR category (median 3 v 4, P = .01). DISCUSSION: Lower TR category, younger age, and larger nodule size were associated with false-negative FNA of thyroid nodules. These findings should be taken into context when counseling patients with thyroid nodules who have a benign FNA.

Rituximab leading to an atypical presentation of neuroborreliosis and false negative serology.

Two patients, recently treated with the B-cell-depleting monoclonal antibody, rituximab, had 2-3 months of progressive systemic symptoms; comprehensive investigations did not clarify the diagnosis. Transient radicular pain at disease onset had suggested neuroborreliosis, but seronegativity and an atypical clinical course made this unlikely. However, PCR identified Borrelia burgdorferi DNA in cerebrospinal fluid, establishing the diagnosis of neuroborreliosis. Both the clinical picture and the laboratory findings can be atypical in people with neuroborreliosis who have recently been treated with rituximab. In B-cell depleted patients living in endemic areas, one should suspect neuroborreliosis even when the typical symptoms are drowned out by more atypical symptoms; PCR should be used as a diagnostic supplement when the serological response is uncertain or absent.

Reconstrucción mamaria diferida con colgajo de dorsal ancho: aportación de la ecografía Doppler-Dúplex / Delayed breast reconstruction with latissimus dorsi fiap: contribution of Doppler-Duplex ultrasound

Introducción y objetivo: Para obtener buenos resultados en reconstrucción mamaria autóloga con colgajo de dorsal ancho se requiere verificar la presencia de una vascularización tóracodorsal adecuada. En el presente trabajo evaluamos la aportación de la ecografía Doppler-Dúplex para la localización de la arteria torácodorsal, previa a la reconstrucción mamaria diferida con colgajo de dorsal ancho. Material y método: Revisión de 51 pacientes con antecedentes de cirugía axilar por cáncer de mama candidatas a reconstrucción diferida con colgajo homolateral del músculo dorsal ancho. La exploración ecográfica la realizó un solo radiólogo utilizando la modalidad ecográfica Doppler-Dúplex. Resultados: Entre las 51 pacientes, se localizó la arteria tóracodorsal mediante ecografía en 39 casos (76.47%). En 12 casos no se pudo localizar o bien su identificación resultó dudosa. Entre estos 12 casos, en 8 se realizó angio-tomografía computarizada o bien angio-resonancia magnética que identificaron la arteria en 5 casos. En los otros 3, las pacientes rechazaron las exploraciones y no se sometieron a reconstrucción mediante la técnica estudiada o bien no se reconstruyeron. Se dispone de datos confirmados en 47 casos, entre los cuales no se ha visualizado vascularización tóracodorsal en 3 casos, lo que supone un 6.38%. Los parámetros diagnósticos resultantes fueron: sensibilidad 88.63%; especificidad 100%; valor predictivo positivo 100%;y valor predictivo negativo 37.50%, con una exactitud del 89.36%. Conclusiones: En base a nuestra experiencia podemos concluir que, siempre que se disponga de la experiencia y los medios técnicos adecuados, la ecografía Doppler-Dúplex debería ser el primer procedimiento a utilizar para la evaluación de la vascularización tóracodorsal. y en el caso de no reunir tales requisitos o bien si la ecografía fuera dudosa/negativa, realizar otros métodos como la angio-tomografía computarizada o la angio-resonancia magnética(AU).

Background and objective: To obtain good results with autologous latissimus dorsi flap in breast reconstruction it's necessary to verify the presence of adequate thoracodorsal vascularity. In this paper we evaluate the contribution of Doppler-Duplex ultrasound for the localization of the thoracodorsal vessels prior to delayed breast reconstruction with a dorsal fap. Methods: Review of 51 patients with a history of axillary surgery for breast cancer, candidates for delayed breast reconstruction with an ipsilateral flap of the latissimus dorsi muscle. The ultrasound examination was performed by a single radiologist using the Doppler-Duplex ultrasound modality. Results: Among the 51 patients, the thoracodorsal artery was located by ultrasound in 39 cases (76.47%). In 12 cases it could not be located or its identification was doubtful. Among these 12 cases, 8 underwent computed tomography angiography or magnetic resonance angiography, which identified the artery in 5 cases. In the remaining 3 cases the patients refused such examinations and did not undergo reconstruction. Confirmed data are available in 47 cases, among which thoracodorsal vasculature was not visualized in 3 cases, which represents 6.38%,The resulting diagnostic parameters were: sensitivity 88.63%; specificity 100%; positive predictive value 100%; and negative predictive value 37.50%, with an accuracy of 89.36%. Conclusions: From our experience we can conclude that,when the appropriate experience and equipment are available, Doppler-Duplex ultrasound should be the first procedure to be used for the evaluation of the thoracodorsal vasculature. And in the case of not meeting these requirements or the ultrasound was doubtful/negative, perform other methods such as computed tomography angiography or magnetic resonance angiography. Level of evidence 5c Diagnostic.(AU)

Comparison of Two Shiga Toxin-producing Escherichia coli (STEC) Isolation Protocols in Raw Cow's Milk Cheese Enrichment Broths: Direct STEC Isolation Versus Techniques Based on Immuno-concentration.

The presence of Shiga toxin-producing Escherichia coli (STEC) in dairy products made with raw milk is a major concern for food safety authorities and industries. Two approaches have been proposed to isolate STEC from food. In the IC-Protocol (immuno-concentration protocol), specific serogroups are identified in the enrichment broth after the detection of the stx and eae genes. An immuno-concentration of the targeted serogroups is performed before isolating them on specific media. In the DI-Protocol (direct isolation protocol), a direct isolation of all STEC present in the enrichment broth is carried out after the detection of stx genes. We compared the ability of these two methods to isolate STEC O26:H11, O103:H2, O111:H8, O145:H28, and O157:H7 after artificial inoculation in four different raw milk cheeses. Across all serogroups and cheese types, STEC were isolated in 83.3% of samples when using the IC-Protocol but only 53.3% of samples with the DI-Protocol. For two cheese types, the DI-Protocol failed to isolate STEC O157:H7 strains altogether. Our results suggest that IC-Protocol is a robust methodology to effectively isolate STEC across a range of cheese types.

Low-cost solutions incorporated in a standard surgical pathway for early breast cancer: A pilot study.

We present the results of incorporation of low-cost solutions to provide a standard surgical care for early breast cancer (EBC) patients. This surgical pathway consists of a low-cost vacuum-assisted core needle biopsy, sentinel lymph node biopsy (SLNB) using low-cost methylene blue and fluorescin dyes under local anesthesia and oncoplastic breast surgery. Patients assessed as clinically node-negative axilla underwent such treatment. SLNB using low-cost dyes was performed without any complication. Oncoplastic surgical techniques were opted for in 32 patients, and the lumps were all excised with a ∼1-cm all-around margin on the final histopathological examination. Standard breast cancer surgery can be provided in low-resource settings to eligible EBC patients with low-cost solutions.

Risk of thyroid carcinoma in patients treated surgically with assumed benign cytology in Riyadh, Saudi Arabia.

Objectives: This study aimed to report the rate of thyroid malignancy in benign fine-needle aspirations (Bethesda II) at King Abdulaziz Medical City and evaluate the factors that affect false-negative outcomes of FNA. Methods: All patients referred for thyroidectomy from 2009 to 2019 were reviewed (n = 1968). Only patients with a benign FNA, corresponding to the Bethesda II, were included (n = 384). Information on age, gender, body mass index (BMI), serum thyroid-stimulating hormone, type of surgery and histopathological outcomes were retrieved. Results: Of the sample (n = 384) with an initial benign FNA, 63 patients had a malignancy on postoperative pathological examination, yielding an overall false-negative rate of 16.4%. The most frequently reported histopathological type was papillary thyroid microcarcinomas (n = 52). For the false-negative group, the mean age was 43.8 years (range 21-70 years) with an 84.1% female predominance. The surgical choice for 74% (n = 46) of cases was total thyroidectomy. Age, gender, thyroid function and BMI did not affect the false-negative rate of benign FNA (p > 0.05). Conclusions: This study found a higher risk of malignancy compared to the literature related to benign FNA. The risk of malignancy should be considered, even with benign FNA.

Indeterminate mycobacterium tuberculosis QuantiFERON post Moderna mRNA Covid-19 vaccination.

We report an interesting case of an indeterminate MTB QuantiFERON for a 26-year-old healthy soldier planned for a routine field exercise to Brunei. Further medical history revealed that the patient had a Moderna mRNA Covid-19 vaccine the day before his MTB QuantiFERON test. The patient was subsequently asked to repeat a T-spot test which was non-reactive, there were no longer any issues with the positive control for the T-spot test. Current Covid-19 research suggests that infection causes a dysregulation of the immune system, perhaps this might also be extrapolated where a Covid-19 vaccine might provoke an immune response which might interfere with some immunological assays. In summary there should be more research invested into the immunological interactions that the newly developed Covid-19 vaccinations have with our existing immunological tests such as QuantiFERON tests which forms a key cornerstone in our fight against tuberculosis.