Prevalence of infectious pathogens in Crohn's disease

The importance of infectious pathogens in Crohn's disease (CD) is still under debate. Therefore, we examined a panel of potential viral and bacterial pathogens in a large series of CD patients and controls.     

Efficacy and Safety of Infliximab Therapy and Predictors of Response in Korean Patients with Crohn's Disease: A Nationwide,Multicenter Study

PurposeInfliximab is currently used for the treatment of active Crohn''s disease (CD). We aimed to assess the efficacy and safety of infliximab therapy and to determine the predictors of response in Korean patients with CD.ResultsIn patients with luminal CD, the rates of clinical response and remission at week 14 were 89.2% and 60.0%, respectively. Male gender and isolated colonic disease were associated with higher remission rates at week 14. In week-14 responders, the probabilities of sustained response and remission were 96.2% and 93.3% at week 30 and 88.0% and 77.0% at week 54, respectively. In patients with fistulizing CD, clinical response and remission were observed in 85.0% and 56.2% of patients, respectively, at week 14. In week-14 responders, the probabilities of sustained response and remission were 94.0% and 97.1%, respectively, at both week 30 and week 54. Thirty-nine patients (12.3%) experienced adverse events related to infliximab. Serious adverse events developed in 19 (6.0%) patients including seven cases of active pulmonary tuberculosis.ConclusionInfliximab induction and maintenance therapy are effective and well tolerable in Korean patients with luminal and fistulizing CD. However, clinicians must be aware of the risk of rare yet critical adverse events.     

Comparison of diagnostic performance of three real-time PCR kits for detecting Mycobacterium species

Purpose

PCR is widely used for rapidly and accurately detecting Mycobacterium Species. The purpose of this study was to assess the diagnostic performance of three real-time PCR kits and evaluate the concordance with two older PCR methods.

Materials and Methods

Using 128 samples, the five PCR methods were assessed, including an in-house PCR protocol, the COBAS Amplicor MTB, the COBAS TaqMan MTB, the AdvanSure TB/NTM real-time PCR, and the Real-Q M. tuberculosis kit. The discrepant results were further examined by DNA sequencing and using the AdvanSure Mycobacteria Genotyping Chip for complete analysis.

Results

For Mycobacterium tuberculosis (MTB) detection, all five kits showed 100% matching results (positive; N = 11 and negative; N = 80). In non-tuberculous mycobacterium (NTM) discrimination, the AdvanSure yielded two true-positive outcomes from M. intracellulare and one false positive outcome, while the Real-Q resulted in one true-positive outcome and one false negative outcome for each case and another false negative result using the provided DNA samples.

Conclusion

Real-time PCR, yielded results that were comparable to those of the older PCR methods for detecting MTB. However, there were disagreements among the applied kits in regard to the sample test results for detecting NTM. Therefore, we recommend that additional confirmatory measures such as DNA sequencing should be implemented in such cases, and further research with using a larger numbers of samples is warranted to improve the detection of NTM.     

Comparative Evaluation of Several Gene Targets for Designing a Multiplex-PCR for an Early Diagnosis of Extrapulmonary Tuberculosis

Purpose

Diagnosis of extrapulmonary tuberculosis (EPTB) poses serious challenges. A careful selection of appropriate gene targets is essential for designing a multiplex-polymerase chain reaction (M-PCR) assay.

Materials and Methods

We compared several gene targets of Mycobacterium tuberculosis, including IS6110, devR, and genes encoding MPB-64 (mpb64), 38kDa (pstS1), 65kDa (hsp65), 30kDa (fbpB), ESAT-6 (esat6), and CFP-10 (cfp10) proteins, using PCR assays on 105 EPTB specimens. From these data, we chose the two best gene targets to design an M-PCR.

Results

Among all gene targets tested, mpb64 showed the highest sensitivity (84% in confirmed cases and 77.5% in clinically suspected cases), followed by IS6110, hsp65, 38kDa, 30kDa, esat6, cfp10, and devR. We used mpb64+IS6110 for designing an M-PCR assay. Our M-PCR assay demonstrated a high sensitivity of 96% in confirmed EPTB cases and 88.75% in clinically suspected EPTB cases with a high specificity of 100%, taking clinical diagnosis as the gold standard.

Conclusion

These M-PCR results along with the clinical findings may facilitate an early diagnosis of EPTB patients and clinical management of disease.     

Comparison of in-house PCR with conventional techniques and Cobas Amplicor M. tuberculosis kit for detection of Mycobacterium tuberculosis

PURPOSE: Polymerase chain reaction (PCR) assay, introduced as a fast and sensitive diagnostic method, is useful in detecting Mycobacterium tuberculosis. The purpose of this study was to evaluate the usefulness of in-house PCR assay in the detection of Mycobacterium tuberculosis by comparing PCR results with conventional diagnostic techniques and Cobas Amplicor M. tuberculosis kit. MATERIALS AND METHODS: We retrospectively assessed the diagnostic yield of in-house PCR method employed for the amplification IS6110 sequences in 2,973 specimens. We also compared in-house PCR with Cobas Amplicor M. tuberculosis kit in 120 specimens collected from June to July 2006. Routine acid-fast stain (AFS) and culture assay were also performed and analyzed. RESULTS: Of 2,973 cases, 2,832 cases (95.3%) showed consistent results between in house PCR, AFS and culture methods, whereas 141 (4.7%) displayed inconsistent results. The sensitivities, specificities, and positive and negative predictive values of each method were as follows: 77.5%, 99.7%, 95.5%, and 98.0%, respectively for PCR; 49.2%, 100%, 100%, and 95.7%, respectively, for AFS method; and 80.7%, 100%, 100%, and 98.3%, respectively, for culture assay. Consistent results between PCR and Cobas Amplicor M. tuberculosis kit were shown in 109 cases (90.8%). The sensitivities, specificities, and positive and negative predictive values of each method were as follows: 81.3%, 98.9%, 96.3%, and 93.5% respectively for PCR and 71.9%, 100%, 100%, and 90.7%, respectively, for Cobas Amplicor kit. CONCLUSION: In-house PCR and Cobas Amplicor kit show high sensitivity and specificity, and are reliable tests in the diagnosis of tuberculosis.     

Disturbances in apoptosis of lamina propria lymphocytes in Crohn's disease

Introduction

The aim of this study was to assess the potential mechanisms providing resistance to apoptosis of lamina propria lymphocytes (LPL) directlyin intestinal tissues from patients with Crohn''s disease (CD).

Material and methods

Fifty CD patients were enrolled in the study. The control group consisted of healthy patients who underwent surveillance colonoscopy after endoscopic polypectomy. Each CD patient underwent colonoscopy with tissue sampling from inflamed areas of the colon with the assessment of immunohistochemical expression of active caspase 3, Fas, tumour necrosis factor receptor 1 (TNFR1), Bcl-2, Bax, CD4 and CD8. This was compared with healthy intestinal mucosa.

Results

The expression of active caspase 3 was significantly lower in LPL in CD (0.4 ±0.3 vs. 2.8 ±1.5; p = 0.0002). A statistically significant increase of CD4 and CD8 positive cells was noted in CD (2.3 ±0.5 vs. 1.2 ±0.2, p < 0.0001; 2.1 ±0.3 vs. 1.1 ±0.3, p < 0.0001, respectively). It was associated with a significant increase of the Bcl-2 (6.7 ±2.7 vs. 2.9 ±0.8; p < 0.0001) and a decrease of the Bax protein expression (3.4 ±2.1 vs. 5.5 ±1.8; p < 0.0001) in CD. The expression of Fas and TNFR1 did not differ between the study groups.

Conclusions

LPL in CD are resistant to apoptosis when compared with physiological conditions. This is probably due to an imbalance in Bcl-2 family proteins. TNFR1-related pathway is probably not involved in disturbances of LPL apoptosis in CD.     

Serum levels and mesenteric fat tissue expression of adiponectin and leptin in patients with Crohn's disease

Crohn''s disease (CD) is characterized by inflammation and an aetiology that is still unknown. Hypertrophy of mesenteric fat is a reflection of disease activity, as this fat covers the entire length of the affected area. Adipocytes synthesize leptin and adiponectin, adipocytokines responsible for pro- and anti-inflammatory effects. Therefore, we evaluated serum levels of adiponectin and leptin, as well as mesenteral expression of adiponectin in active CD and those in remission. Sixteen patients with ileocaecal CD followed at the Outpatient Clinic, Coloproctology Unit of University of Campinas Clinical Hospital, participated in the study. Analysis of serum adiponectin and leptin by enzyme-linked immunosorbent assay was performed in patients with active CD (ACD group), remission CD (RCD group) and in six healthy controls. Ten patients with active ileocaecal CD (FCD group) and eight patients with non-inflammatory disease selected for surgery were also studied. The specimens were snap-frozen and the expression of adiponectin was determined by immunoblot of protein extracts. Serum C-reactive protein levels were higher in the ACD group when compared to the others and no difference of body mass index was observed between the groups. Serum adiponectin was lower in the ACD group when compared to control, but no differences were seen when comparing the ACD and RCD groups. Mesenteric adiponectin expression was lower in the FCD group when compared to the FC group. Serum leptin was similar in all groups. The lower levels of serum and mesenteric adiponectin in active CD suggest a defective regulation of anti-inflammatory pathways in CD pathogenesis.     

Adjuvant modulation of the cytokine balance in Mycobacterium tuberculosis subunit vaccines; immunity, pathology and protection

It is known that protection against tuberculosis is mediated primarily by T helper type 1 (Th1) cells but the influence of the Th1/Th2 balance of a vaccination response on the subsequent protection and pathology during infection has not been studied in detail. We designed a panel of Ag85B-ESAT-6 subunit vaccines based on adjuvants with different Th1/Th2-promoting activities and studied cellular responses, bacterial replication and pathology in the lungs of mice infected with Mycobacterium tuberculosis. All vaccines induced cell-mediated and humoral responses but with markedly different interferon-γ : interleukin-5 (IFN-γ : IL-5) and immunoglobulin G1 (IgG1) : IgG2 ratios. The vaccines promoted different levels of control of bacterial replication with the most efficient protection being exerted by cationic liposomes containing monophosphoryl lipid A and low to completely absent immunity with conventional aluminium. The level of protection correlated with the amount of IFN-γ produced in response to the vaccine whereas there was no inverse correlation with the level of IL-5. Characterizing a protective response was an accelerated recruitment of IL-17 and IFN-γ-producing lymphocytes resulting in the early formation of granulomas containing clustered inducible nitric oxide synthase-activated macrophages. In comparison, non-protected mice exhibited a different inflammatory infiltrate rich in neutrophil granulocytes. This study indicates that the adjuvant component of a tuberculosis vaccine may be crucial in determining the kinetics by which effective granulomas, pivotal in controlling bacterial growth, are formed.     

Growth of recombinant Mycobacterium tuberculosis H37Ra in mouse macrophages

Mycobacterium tuberculosis H37Rv and H37Ra were derived from the same parental strain but differ strikingly in their virulence for experimental animals. Transfer of genetic material between these closely related strains resulted in the isolation of a number of recombinant H37Ra clones bearing the in vivo growth-promoting ivg locus of H37Rv. The recombinant strain was phagocytosed by murine peritoneal macrophages infected in vivo or in vitro and their intracellular growth rates were compared with the vector control. The intracellular growth of the recombinant was significantly faster than the vector control, but substantially slower than the wild-type H37Rv control, regardless of the method used to infect the macrophages. The slower intracellular growth observed for the recombinant strains was not due to a genetically induced metabolic defect, since they grew in synthetic liquid medium at rates equal to those observed for both H37Rv and H37Ra. Peritoneal macrophage monolayers provide a rapid and convenient assay by which to screen H37Ra recombinants for the presence of putative virulence genes.     

Association among genetic predisposition,gut microbiota,and host immune response in the etiopathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD), which includes Crohn''s disease (CD) and ulcerativecolitis (UC), is a chronic disorder that affects thousands of people around theworld. These diseases are characterized by exacerbated uncontrolled intestinalinflammation that leads to poor quality of life in affected patients. Although theexact cause of IBD still remains unknown, compelling evidence suggests that theinterplay among immune deregulation, environmental factors, and genetic polymorphismscontributes to the multifactorial nature of the disease. Therefore, in this review wepresent classical and novel findings regarding IBD etiopathogenesis. Considering thegenetic causes of the diseases, alterations in about 100 genes or allelic variants,most of them in components of the immune system, have been related to IBDsusceptibility. Dysbiosis of the intestinal microbiota also plays a role in theinitiation or perpetuation of gut inflammation, which develops under altered orimpaired immune responses. In this context, unbalanced innate and especially adaptiveimmunity has been considered one of the major contributing factors to IBDdevelopment, with the involvement of the Th1, Th2, and Th17 effector population inaddition to impaired regulatory responses in CD or UC. Finally, an understanding ofthe interplay among pathogenic triggers of IBD will improve knowledge about theimmunological mechanisms of gut inflammation, thus providing novel tools for IBDcontrol.     

PTPN2 is associated with Crohn's disease and its expression is regulated by NKX2-3

PTPN2 is a risk gene for Crohn's disease (CD). We investigated whether PTPN2 genetic variants (rs2542151 and rs2542152) were associated with CD in a familial IBD registry. Both rs2542151 and rs2542152 are associated with CD, but not ulcerative colitis (UC). mRNA expression levels of PTPN2 were significantly increased in intestinal tissues (p=0.0493), and nearly significantly increased in B cells (p=0.0889) from CD patients, but not significantly altered in UC. cDNA microarray results found that PTPN2 was down-regulated by NKX2-3 knockdown in human cells. We confirmed this observation by RT-PCR analyses in NKX2-3 knockdown in B cells from IBD patients and human intestinal microvascular endothelial cells (HIMEC). In addition, we found that mRNA expression of another IBD-associated gene, NKX2-3, was increased in intestinal tissues and B cells from CD patients, but not significantly increased in UC patients. A positive correlation was observed between mRNA expression of PTPN2 and NKX2-3 in B cells and in intestinal tissues from both CD and UC patients. These results suggest that PTPN2 may have an important role in CD pathogenesis and may represent a potential diagnostic and therapeutic target for IBD.     

英夫利西单抗治疗克罗恩病黏膜愈合的血清差异蛋白质表达研究

目的:寻找与英夫利西单抗(infliximab,IFX)治疗克罗恩病(Crohn’s disease,CD)黏膜愈合(mucosal healing,MH)相关的血清蛋白质生物标志物。方法:采集7例经IFX治疗获得MH的CD患者治疗前(0周,A组)和治疗后(14周,B组)的血清,以及7例未获得MH的CD患者(0周为C组,14周为D组)的血清。采用荧光标记双向差异凝胶电泳的方法,比较A组与B组之间、C组与D组之间、A组与C组之间以及B组与D组之间的蛋白质组学差异,并对差异表达的蛋白质斑点进行基质辅助激光解吸/电离飞行时间串联质谱初步鉴定和生物信息学分析。结果:(1)A组与B组、C组与D组、A组与C组以及B组与D组之间比较分别存在36、3、10和31个差异表达的蛋白质斑点,共计存在44个显著差异表达的蛋白质斑点。(2)上述各组之间的差异斑点分别初步鉴定出17、2、2和15种蛋白质,共计存在19种差异表达的蛋白质,包括载脂蛋白E、载脂蛋白A-I、补体因子H等。(3)基于STRING数据库绘制了蛋白质网状功能图。结论:IFX治疗获得MH的CD患者治疗前后的血清蛋白质表达谱存在差异,获得MH和未获得MH的患者血清表达谱亦存在差异,其中19种蛋白质有可能成为预测CD患者使用IFX获得MH的生物标志物。     

A Simple and Efficient Multiplex PCR Assay for the Identification of Mycobacterium Genus and Mycobacterium tuberculosis Complex to the Species Level

Purpose

The Mycobacterium tuberculosis complex comprises M. tuberculosis, M. bovis, M. bovis bacillus Calmette-Guérin (BCG) and M. africanum, and causes tuberculosis in humans and animals. Identification of Mycobacterium spp. and M. tuberculosis complex to the species level is important for practical use in microbiological laboratories, in addition to optimal treatment and public health.

Materials and Methods

A novel multiplex PCR assay targeting a conserved rpoB sequence in Mycobacteria spp., as well as regions of difference (RD) 1 and RD8, was developed and evaluated using 37 reference strains and 178 clinical isolates.

Results

All mycobacterial strains produced a 518-bp product (rpoB), while other bacteria produced no product. Virulent M. tuberculosis complex strains, M. tuberculosis, M. bovis and M. africanum, produced a 254-bp product (RD1), while M. bovis BCG, M. microti and nontuberculous mycobacteria produced no RD1 region product. Additionally, M. tuberculosis and M. africanum produced a 150-bp product (RD8), while M. bovis and M. bovis BCG produced a 360-bp product (deleted form of RD8). M. microti and nontuberculous mycobacteria produced no RD8 region product. This assay identified all Mycobacterium spp. and all M. tuberculosis complex strains to the species level.

Conclusion

The multiplex PCR assay of the present study could be implemented as a routine test in microbiology laboratories, and may contribute to more effective treatment and surveillance of tuberculosis stemming from the M. tuberculosis complex.     

The effect of IL-10 genetic variation and interleukin 10 serum levels on Crohn's disease susceptibility in a New Zealand population

Interleukin (IL)-10 has important effects in immunoregulation and inflammation, and previous studies have provided evidence for the involvement of IL-10 in the pathogenesis of Crohn's disease (CD). In this study, we investigated whether genetic variants of the IL-10 gene were associated with CD in a New Zealand population. Three single nucleotide polymorphisms (SNPs) in the promoter region of IL-10 (rs1800871, rs1800872, and rs1800896) and a flanking SNP, rs3024505, were genotyped in a well-characterized New Zealand dataset consisting of 342 CD cases and 610 controls. Furthermore, we measured serum IL-10 levels in a number of the CD patients and controls and examined whether a relationship existed between these polymorphisms and serum IL-10 levels. We demonstrated an association with CD for SNPs rs3024505 and rs1800896, and phenotypic analysis indicated an association of rs3024505 with an early age at first diagnosis, stricturing CD behavior, and requirement for bowel resection. We also observed that IL-10 concentration was significantly higher in CD patients than in the controls and that the T allele of rs1800896, the A allele of rs1800871, and the T allele of rs1800872 were associated with increased serum IL-10 levels.     

Development of a Quantitative Sandwich Enzyme-Linked Immunosorbent Assay for Detecting the MPT64 Antigen of Mycobacterium tuberculosis

Purpose

Tuberculosis (TB) is a major infectious disease and is responsible for two million deaths annually. For the identification and quantitation of Mycobacterium tuberculosis (M. tuberculosis), a causative agent of TB, a sandwich enzyme-linked immunosorbent assay (ELISA) against the MPT64 protein of M. tuberculosis, an antigen marker of the M. tuberculosis complex, was developed.

Materials and Methods

The MPT64 protein was expressed, and anti-MPT64 monoclonal antibodies were prepared. A sandwich ELISA was established using recombinant MPT64 protein and anti-MPT64 monoclonal antibodies. The sandwich MPT64 ELISA was evaluated using reference and clinical mycobacterial strains.

Results

The sandwich MPT64 ELISA detected MPT64 protein from 2.1 ng/mL to 250 ng/mL (equivalent to 1.7×10⁴ CFU/mL and 2.0×10⁶ CFU/mL). All 389 clinical M. tuberculosis isolates tested positive in the sandwich MPT64 ELISA (sensitivity, 100%), and the assay showed no cross reactivity to any tested nontuberculous mycobacterial strain (specificity, 100%).

Conclusion

The sandwich MPT64 ELISA is a highly sensitive and quantitative test for MPT64 protein, which can identify M. tuberculosis.     

Molecular Strain Typing of Mycobacterium tuberculosis: a Review of Frequently Used Methods

Tuberculosis, caused by the bacterium Mycobacterium tuberculosis, remains one of the most serious global health problems. Molecular typing of M. tuberculosis has been used for various epidemiologic purposes as well as for clinical management. Currently, many techniques are available to type M. tuberculosis. Choosing the most appropriate technique in accordance with the existing laboratory conditions and the specific features of the geographic region is important. Insertion sequence IS6110-based restriction fragment length polymorphism (RFLP) analysis is considered the gold standard for the molecular epidemiologic investigations of tuberculosis. However, other polymerase chain reaction-based methods such as spacer oligonucleotide typing (spoligotyping), which detects 43 spacer sequence-interspersing direct repeats (DRs) in the genomic DR region; mycobacterial interspersed repetitive units–variable number tandem repeats, (MIRU-VNTR), which determines the number and size of tandem repetitive DNA sequences; repetitive-sequence-based PCR (rep-PCR), which provides high-throughput genotypic fingerprinting of multiple Mycobacterium species; and the recently developed genome-based whole genome sequencing methods demonstrate similar discriminatory power and greater convenience. This review focuses on techniques frequently used for the molecular typing of M. tuberculosis and discusses their general aspects and applications.     

Genetic association study suggests a role for SP110 variants in lymph node tuberculosis but not pulmonary tuberculosis in north Indians

Ethnic specificity is a key determinant in understanding the association of genetic variants with outcome of disease susceptibility. SP110, a component of the nuclear body, has been subjected to association studies with conflicting results. In this study we probed SP110 variants in pulmonary (PTB) and lymph node tuberculosis (LNTB) cases to explore their role in controlling susceptibility to Mycobacterium tuberculosis infection in north Indians. We genotyped 24 SP110 variants in over 140 north Indian tuberculosis cases and 78 ethnicity-matched controls. The SP110 gene variants were available from public databases. The cases and controls were free of any population stratification when subjected to Eigenstrat principal component analysis. Genotyping was carried out using the Sequenom MassARRAY platform. Applying exclusion criteria, 11 single nucleotide polymorphisms (SNPs) of the LNTB panel and 13 SNPs of the PTB panel passed all filters and were analyzed further. No significant association was observed between SP110 variants and PTB. Surprisingly, we discovered evidence of an association of SP110 variants with LNTB, a form of extrapulmonary tuberculosis, at 3 loci, namely, rs6436915, rs1427294, and rs1346311. When permutations analysis (n = 10,000) of allelic p values was undertaken, only rs1427294 passed the test with its p value remaining statistically significant. The C allele of rs1427294 exhibited a 5-fold risk of developing LNTB. No significant haplotypes were observed. In the pilot study presented here, our results provide evidence for the first time that SP110 may be a risk determinant locus in LNTB while confirming a doubtful role of SP110 in PTB in north Indians. In general, the results might indicate a role of SP110 variants in extrapulmonary tuberculosis rather than PTB.     

Classical and recent advances in the treatment of inflammatory bowel diseases

Crohn''s disease (CD) and ulcerative colitis (UC) are intestinal disorders that comprise the inflammatory bowel diseases (IBD). These disorders have a significant effect on the quality of life of affected patients and the increasing number of IBD cases worldwide is a growing concern. Because of the overall burden of IBD and its multifactorial etiology, efforts have been made to improve the medical management of these inflammatory conditions. The classical therapeutic strategies aim to control the exacerbated host immune response with aminosalicylates, antibiotics, corticosteroids, thiopurines, methotrexate and anti-tumor necrosis factor (TNF) biological agents. Although successful in the treatment of several CD or UC conditions, these drugs have limited effectiveness, and variable responses may culminate in unpredictable outcomes. The ideal therapy should reduce inflammation without inducing immunosuppression, and remains a challenge to health care personnel. Recently, a number of additional approaches to IBD therapy, such as new target molecules for biological agents and cellular therapy, have shown promising results. A deeper understanding of IBD pathogenesis and the availability of novel therapies are needed to improve therapeutic success. This review describes the overall key features of therapies currently employed in clinical practice as well as novel and future alternative IBD treatment methods.     

Description of Pediatric Tuberculosis Evaluated in a Referral Center in Istanbul Turkey

Purpose

Diagnosis of tuberculosis (TB) in children is more challenging than in adults. This study aimed to describe demographical, clinical and laboratory findings of children diagnosed with tuberculosis in Turkey, including the issues of contact tracing, culture positivity and forms of the disease.

Materials and Methods

Clinical and laboratory data of 51 children with a mean age of 8.0±4.6 years who were diagnosed with TB were retrospectively reviewed. Main diagnostic tools included tuberculin skin test, chest X-ray, sputum/gastric aspirate culture with sensitivity testing, and direct microscopy for acid-fast bacilli on available samples. Clinical characteristics and outcomes of the patients were examined.

Results

Thirty-six (70.6%) children were diagnosed with intra-thoracic and 15 (29.4%) with extra-thoracic tuberculosis. Twenty-eight of the patients had a positive Bacillus Calmette-Guérin vaccine scar (28/51, 54.9%) and 23/51 (45.1%) had a positive tuberculin skin test. An adult TB contact was identified in 27 (52.9%) of the cases. On direct microscopy, acid-fast bacilli were found in nine (17.6%) patients and positive culture for Mycobacterium tuberculosis was found in 19 (37.3%). Drug resistance to isoniazid was detected in four (7.8%). One patient with nephrotic syndrome and miliary tuberculosis died during follow-up. All other patients responded well to the treatment.

Conclusion

Focusing on active contact tracing among all household contacts of tuberculous cases may be helpful in early identification and controlling childhood disease, even in regions with low disease prevalence. Adopting a suspicious and proactive approach in this particular age group is warranted.