Biochemical Characterization of Thermostable Acrylamide Amidohydrolase from Aspergillus fumigatus with Potential Activity for Acrylamide Degradation in Various Food Products

Acrylamide is the major by-product of the Maillard reactions in foods with the overheating processes of L-asparagine-rich foods with reducing sugars that usually allied with neurotoxicity and carcinogenicity. Several approaches have been used to prevent the formation of acrylamide, however, degrading the already formed acrylamide in foods remains unequivocal. Acrylamide hydrolyzing enzyme "amidohydrolase" is one of the most promising enzymes for acrylamide degradation in foods. So, amidohydrolase "amidase" from thermotolerant Aspergillus fumigatus EFBL was purified to their electrophoretic homogeneity by gel-filtration and ion-exchange chromatography, with overall purification folds 2.8 and yield 9.43%. The apparent molecular subunit structure of the purified A. fumigatus amidase was 50 kDa, with highest activity at reaction temperature of 40 °C and pH of 7.5 The enzyme displayed a significant thermal stability as revealed from the value of T1/2 (13.37 h), and thermal denaturation rate (Kr 0.832 × 10-3 min) at 50 °C, with metalloproteinic identity. The purified enzyme had a significant activity for acrylamide degradation in various food products such as meat, cookies, potato chips, and bread as revealed from the HPLC analysis and LC-MS analysis. So, with the purified amidase, the acrylamide in the food products was degraded by about 95% to acrylic acid, ensuring the possibility of using this enzyme in abolishing the toxic acrylamide in the foods products. This is the first report exploring the potency of A. fumigatus amidase for an actual degradation of acrylamide in foods efficiently. Further biochemical analyses are ongoing to assess the affinity of this enzyme for selective hydrolyses of acrylamide in foods, without affecting the beneficial stereochemical related compounds.

Aspergillus Niger thermostable Cytosine deaminase-dextran conjugates with enhanced structure stability, proteolytic resistance, and Antiproliferative activity

Cytosine deaminase (CDA) is a prodrug mediating enzyme converting 5-flurocytosine into 5-flurouracil with profound broad-range anticancer activity towards various cell lines. Availability, molecular stability, and catalytic efficiency are the main limiting factors halting the clinical applications of this enzyme on prodrug and gene therapies, thus, screening for CDA with unique biochemical and catalytic properties was the objective. Thermotolerant/ thermophilic fungi could be a distinctive repertoire for enzymes with affordable stability and catalytic efficiency. Among the recovered thermotolerant isolates, Aspergillus niger with optimal growth at 45 °C had the highest CDA productivity. The enzyme was purified, with purification 15.4 folds, molecular mass 48 kDa and 98 kDa, under denaturing and native PAGE, respectively. The purified CDA was covalently conjugated with dextran with the highest immobilization yield of 75%. The free and CDA-dextran conjugates have the same optimum pH 7.4, reaction temperature 37 °C, and pI 4.5, and similar response to the inhibitors and amino acids suicide analogues, ensuring the lack of effect of dextran conjugation on the CDA conformational structure. CDA-Dextran conjugates had more resistance to proteolysis in response to proteinase K and trypsin by 2.9 and 1.5 folds, respectively. CDA-Dextran conjugates displayed a dramatic structural and thermal stability than the free enzyme, authenticating the acquired structural and catalytic stability upon dextran conjugation. The thermal stability of CDA was increased by about 1.5 folds, upon dextran conjugation, as revealed from the half-life time (T_1/2). The affinity of CDA-conjugates (K_m 0.15 mM) and free CDA (K_m 0.22 mM) to deaminate 5-fluorocytosine was increased by 1.5 folds. Upon dextran conjugation, the antiproliferative activity of the CDA towards the different cell lines "MDA-MB, HepG-2, and PC-3" was significantly increased by mediating the prodrug 5-FC. The CDA-dextran conjugates strongly reduce the tumor size and weight of the Ehrlich cells (EAC), dramatically increase the titers of Caspase-independent apoptotic markers PARP-1 and AIF, with no cellular cytotoxic activity, as revealed from the hematological and biochemical parameters.

Performance-based technical support for drug-resistant TB responses: lessons from the Green Light Committee

Drug-resistant tuberculosis (DR-TB) constitutes a global threat and a major contributor to deaths related to antimicrobial resistance. Despite progress in DR-TB detection and treatment over the last decade, huge gaps remain in treatment coverage, access to quality care and treatment outcome. Global Fund investments have been critical to scaling up the existing and new diagnostic tools, treatment coverage and people-centred service delivery. The United Nations General Assembly (UNGA) high-level meeting represents unprecedented opportunities to accelerate towards addressing DR-TB. Established in 2000 and funded by the Global Fund since 2009, the Green Light Committee (GLC) mechanism has evolved from project approval to providing demand-based technical assistance to countries to scale up response to DR-TB based on their need and priorities. Lessons learnt from the GLC mechanism over 10 years demonstrate that a result-based, systematic and accountable technical assistance model to support scale-up of DR-TB response is critically important. Meeting the UNGA declaration targets requires major scale-up of current efforts and new tools, and hence the need for predictable, consistent and sustained technical support to countries, including through the regional GLC mechanism. The application of the principles and processes of this model could be adapted and replicated to design a similar performance-based and quality-assured technical support mechanism.

Enhancing tuberculosis case finding in Tanzania: implementation of a quality improvement initiative

Tuberculosis (TB) is one of the major causes of morbidity and mortality in Tanzania. A quality improvement (QI) initiative was implemented by the National Tuberculosis Programme with support from The Global Fund to enhance TB case finding. The initiative involved identifying gaps in the quality of services, introducing tools, building capacity of health workers, and strengthening laboratory and referral services. The initiative was piloted at sub-national level and subsequently scaled-up nationally. Overall, 1280 health workers were trained, leading to an 81% cumulative increase in notified TB cases in the pilot region and 4000 additional TB cases notified nationally. The QI initiative could serve as a model for the improvement of TB case notification in other settings.

Conjugation of Aspergillus flavipes Taxol with Porphyrin Increases the Anticancer Activity of Taxol and Ameliorates Its Cytotoxic Effects

Taxol is one of the potential anticancer drugs; however, the yield of Taxol and its cytotoxicity are common challenges. Thus, manipulating the Taxol biosynthetic pathway from endophytic fungi, in addition to chemical modification with biocompatible polymers, is the challenge. Four fungal isolates, namely, Aspergillus flavipes, A. terreus, A. flavus, and A. parasiticus, were selected from our previous study as potential Taxol producers, and their potency for Taxol production was evaluated in response to fluconazole and silver nitrate. A higher Taxol yield was reported in the cultures of A. flavipes (185 µg/L) and A. terreus (66 µg/L). With addition of fluconazole, the yield of Taxol was increased 1.8 and 1.2-fold for A. flavipes and A. terreus, respectively, confirming the inhibition of sterol biosynthesis and redirecting the geranyl phosphate pool to terpenoids synthesis. A significant inhibition of ergosterol biosynthesis by A. flavipes with addition of fluconazole was observed, correlating with the increase on Taxol yield. To increase the Taxol solubility and to reduce its cytotoxicity, Taxol was modified via chemical conjugation with porphyrin, and the degree of conjugation was checked from the Thin layer chromatography and UV spectral analysis. The antiproliferative activity of native and modified Taxol conjugates was evaluated; upon porphyrin conjugation, the activity of Taxol towards HepG2 was increased 1.5-fold, while its cytotoxicity to VERO cells was reduced 3-fold.

Elemental Composition of PM2.5 Aerosol in a Residential-Industrial Area of a Mediterranean Megacity

Very little is known about the elemental composition and possible sources of fine aerosol particles from Mediterranean megacities. Fine aerosol particles were collected at a residential-industrial area in Greater Cairo, Egypt, during the period from October 2010 to May 2011. The elemental compositions of the collected samples were quantified by using a homemade energy dispersive x-ray fluorescence spectrometer, whereas black carbon was quantified by a black smoke detector. Fifteen elements have been quantified. Of these constituents, Ca, C, Cl, S, and Fe had the highest concentrations: greater than 1 µg m^-3. The overall mean mass concentration of the collected samples equals 70 µg m^-3; this value exceeds the European Union annual Air Quality Standard levels. The individual elemental concentrations of the fine particles were found to be dominated by elements linked to mineral dust. Most of the monthly variations of elemental concentrations can be attributed to seasonal meteorological conditions. Other possible sources were vehicle-exhaust and industrial activities. The results pinpoint the problem of identifying different sources when one source, in this case, the nearby deserts, is dominant. The results from this study contribute to the growing knowledge of concentrations, composition, and possible sources of ambient fine particulate matter.

Purification and Characterization of Ornithine Decarboxylase from Aspergillus terreus; Kinetics of Inhibition by Various Inhibitors

l-Ornithine decarboxylase (ODC) is the rate-limiting enzyme of de novo polyamine synthesis in humans and fungi. Elevated levels of polyamine by over-induction of ODC activity in response to tumor-promoting factors has been frequently reported. Since ODC from fungi and human have the same molecular properties and regulatory mechanisms, thus, fungal ODC has been used as model enzyme in the preliminary studies. Thus, the aim of this work was to purify ODC from fungi, and assess its kinetics of inhibition towards various compounds. Forty fungal isolates were screened for ODC production, twenty fungal isolates have the higher potency to grow on L-ornithine as sole nitrogen source. Aspergillus terreus was the most potent ODC producer (2.1 µmol/mg/min), followed by Penicillium crustosum and Fusarium fujikuori. These isolates were molecularly identified based on their ITS sequences, which have been deposited in the NCBI database under accession numbers MH156195, MH155304 and MH152411, respectively. ODC was purified and characterized from A. terreus using SDS-PAGE, showing a whole molecule mass of ~110 kDa and a 50 kDa subunit structure revealing its homodimeric identity. The enzyme had a maximum activity at 37 °C, pH 7.4-7.8 and thermal stability for 20 h at 37 °C, and 90 days storage stability at 4 °C. A. terreus ODC had a maximum affinity (K_m) for l-ornithine, l-lysine and l-arginine (0.95, 1.34 and 1.4 mM) and catalytic efficiency (k_cat/K_m) (4.6, 2.83, 2.46 × 10^-5 mM^-1·s^-1). The enzyme activity was strongly inhibited by DFMO (0.02 µg/mL), curcumin (IC₅₀ 0.04 µg/mL), propargylglycine (20.9 µg/mL) and hydroxylamine (32.9 µg/mL). These results emphasize the strong inhibitory effect of curcumin on ODC activity and subsequent polyamine synthesis. Further molecular dynamic studies to elucidate the mechanistics of ODC inhibition by curcumin are ongoing.

A community-based isoniazid preventive therapy for the prevention of childhood tuberculosis in Ethiopia

BACKGROUND:

Although children in contact with adults with tuberculosis (TB) should receive isoniazid (INH) preventive therapy (IPT), this is rarely implemented.

OBJECTIVE:

To assess whether a community-based approach to provide IPT at the household level improves uptake and adherence in Ethiopia.

METHODS:

Contacts of adults with smear-positive pulmonary TB (PTB+) were visited at home and examined by health extension workers (HEWs). Asymptomatic children aged <5 years were offered IPT and followed monthly.

RESULTS:

Of 6161 PTB+ cases identified by HEWs in the community, 5345 (87%) were visited, identifying 24 267 contacts, 7226 (29.8%) of whom were children aged <15 years and 3102 (12.7%) were aged <5 years; 2949 contacts had symptoms of TB and 1336 submitted sputum for examination. Ninety-two (6.9%) were PTB+ and 169 had TB all forms. Of 3027 asymptomatic children, only 1761 were offered (and accepted) IPT due to INH shortage. Of these, 1615 (91.7%) completed the 6-month course. The most frequent reason for discontinuing IPT was INH shortage.

CONCLUSION:

Contact tracing contributed to the detection of additional TB cases and provision of IPT in young children. IPT delivery in the community alongside community-based TB interventions resulted in better acceptance and improved treatment outcome.

Role of Hyperplasia of Gingival Lymphatics in Periodontal Inflammation

Lymphatic vessels are important for maintenance of tissue fluid homeostasis and afferent antigen transport. In chronic inflammation, lymphangiogenesis takes place and is characterized by lymphatic endothelial cell proliferation and lymphatic hyperplasia. Vascular endothelial growth factor C (VEGFC) is the main known lymphangiogenic growth factor, and its expression is increased in periodontitis, a common chronic infectious disease that results in tissue destruction and alveolar bone loss. The role of lymphangiogenesis during development of periodontitis is unknown. Here, we test if transgenic overexpression of epithelial VEGFC in a murine model is followed by hyperplasia of lymphatic vessels in oral mucosa and if the lymphatic drainage capacity is altered. We also test if lymphatic hyperplasia protects against periodontal disease development. Transgenic keratin 14 (K14)-VEGFC mice had significant hyperplasia of lymphatics in oral mucosa, including gingiva, without changes in blood vessel vasculature. The basal lymph flow was normal but slightly lower than in wild-type mice when oral mucosa was challenged with lipopolysaccharide from Porphyromonas gingivalis. Under normal conditions, K14-VEGFC mice exhibited an increased number of neutrophils in gingiva, demonstrated enhanced phagocyte recruitment in the cervical lymph nodes, and had more alveolar bone when compared with their wild-type littermates. After induction of periodontitis, no strain differences were observed in the periodontal tissues with respect to granulocyte recruitment, bone resorption, angiogenesis, cytokines, and bone-related protein expressions or in draining lymph node immune cell proportions and vascularization. We conclude that overexpression of VEGFC results in hyperplastic lymphatics, which do not enhance lymphatic drainage capacity but facilitate phagocyte transport to draining lymph nodes. Hyperplasia of lymphatics does not protect against development of ligature-induced periodontitis.

Are patients with pulmonary tuberculosis who are identified through active case finding in the community different than those identified in healthcare facilities?

The lack of healthcare access contributes to large numbers of tuberculosis (TB) cases being missed and has led to renewed interest in outreach approaches to increase detection. It is however unclear whether outreach activities increase case detection or merely identify patients before they attend health facilities. We compared adults with cough of >2 weeks' duration recruited in health facilities (1202 participants) or in urban slums (2828 participants) in Nigeria. Participants provided demographic and clinical information and were screened using smear microscopy. The characteristics of smear-positive and smear-negative individuals were compared stratified by place of enrolment. Two hundred nine health facility participants (17.4%) and 485 community-based participants (16.9%) were smear positive for pulmonary TB. Community-based smear-positive cases were older (mean age, 36.3 vs. 31.8 years), had longer cough duration (10.3 vs. 6.8 weeks) and longer duration of weight loss (4.6 vs. 3.6 weeks) than facility-based cases; and they complained more of fever (87.4% vs. 74.6%), chest pain (89.0% vs. 67.0%) and anorexia (79.5% vs. 55.5%). Community smear-negative participants were older (mean, 39.4 vs. 34.0 years), were more likely to have symptoms and were more likely to have symptoms of longer duration than smear-negative facility-based participants. Patients with pulmonary TB identified in the community had more symptoms and longer duration of illness than facility-based patients, which appeared to be due to factors differentially affecting access to healthcare. Community-based activities targeted at urban slum populations may identify a different TB case population than that accessing stationary services.

Genetic diversity analysis of Aspergillus flavus isolates from plants and air by ISSR markers

Aspergillus flavus is one of the most abundant and widely distributed fungi on earth. A. flavus produces aflatoxins (AFs), which are toxic secondary metabolites. AFs have harmful effects on public health (humans and animals) and agricultural crops. Inter-simple sequence repeat (ISSR) markers were used to analyze the genetic diversity of 30 A. flavus isolates from five agricultural crops and air. Genetic similarity coefficients (GSC) ranged from 0.51 to 0.10 based on three ISSR markers for the isolates tested. A. flavus isolates grouped into 6, 5, and 3 clusters using the unweighted pair-group method with arithmetic average of three ISSR markers. This study suggests that ISSR biotechnology is a highly useful tool for characterizing genetic diversity of A. flavus isolated from different sources.

Transcriptional and Proteomic Profiling of Aspergillus flavipes in Response to Sulfur Starvation

Aspergillus flavipes has received considerable interest due to its potential to produce therapeutic enzymes involved in sulfur amino acid metabolism. In natural habitats, A. flavipes survives under sulfur limitations by mobilizing endogenous and exogenous sulfur to operate diverse cellular processes. Sulfur limitation affects virulence and pathogenicity, and modulates proteome of sulfur assimilating enzymes of several fungi. However, there are no previous reports aimed at exploring effects of sulfur limitation on the regulation of A. flavipes sulfur metabolism enzymes at the transcriptional, post-transcriptional and proteomic levels. In this report, we show that sulfur limitation affects morphological and physiological responses of A. flavipes. Transcription and enzymatic activities of several key sulfur metabolism genes, ATP-sulfurylase, sulfite reductase, methionine permease, cysteine synthase, cystathionine β- and γ-lyase, glutathione reductase and glutathione peroxidase were increased under sulfur starvation conditions. A 50 kDa protein band was strongly induced by sulfur starvation, and the proteomic analyses of this protein band using LC-MS/MS revealed similarity to many proteins involved in the sulfur metabolism pathway.

Biochemical and Pharmacokinetic Properties of PEGylated Cystathionine γ-Lyase from KF723837

Cystathionine &#947;-lyase (CGL) was purified to its electrophoretic homogeneity from<i> Aspergillus carneus</i> by various chromatographic approaches. The purified enzyme has four identical subunits of 52 kDa based on SDS and native PAGE analyses. To improve its structural stability, purified CGL was modified by covalent binding to polyethylene glycol moieties. The specific activity of free-CGL and PEG-CGL was 59.71 and 48.71 U/mg, respectively, with a PEGylation yield of 81.5 and 70.7% modification of surface ε-amino groups. Free- and modified CGL have the same pattern of pH stability (8.0-9.0). At 50°C, the thermal stability [half-life time (T_1/2)] of PEG-CGL was increased by 40% in comparison to free-CGL. The activity of CGL was completely inhibited by hydroxylamine and Hg⁺², with no effect by EDTA. Free-CGL (0.04 m<smlcap>M</smlcap>^-1s^-1) and PEG-CGL (0.03 m<smlcap>M</smlcap>^-1s^-1) have a similar catalytic efficiency to <smlcap>L</smlcap>-cystathionine as a substrate. The inhibition constant values of propargylglycine were 0.31 and 0.52 µ<smlcap>M</smlcap> for the free- and PEG-CGL, respectively. By in vitro proteolysis, PEG-CGL retains >50% of its initial activity compared to <10% of the free-CGL for acid protease for 30 min. From in vivo pharmacokinetics in New Zealand white rabbits, the T_1/2 was 19.1 and 28.9 h for the Holo free-CGL and PEG-CGL, respectively, ensuring the role of PEGylation on shielding the CGL surface from proteolytic attack, reducing its antigenicity, and stabilizing its internal Schiff base. By external infusion of pyridoxal 5′-phosphate (10 µ<smlcap>M</smlcap>), the T_1/2 of free- and PEG-CGL was prolonged to 24 and 33 h, respectively, so dissociation of pyridoxal 5′-phosphate was one of the main causes of loss of enzyme activity. The biochemical and hematological responses of rabbits to free- and PEG-CGL were assessed, with relative similarity to the negative control, confirming the nil toxicity of enzymes. The titer of IgG was duplicated in response to free- versus PEG-CGL after 45 days. To the best of our knowledge, this is the first report concerned with purification and PEGylation of CGL from fungi, with higher affinity for <smlcap>L</smlcap>-cystathionine. With further molecular studies, CGL will be a promising enzyme against various cardiovascular diseases and antioxidant deficiency, as well as for generation of a neurotransmitter (H₂S).

Coimmobilization of l-methioninase and glutamate dehydrogenase: Novel approach for L-homoalanine synthesis

L-Homoalanine, a nonnatural amino acid that is rarely found in human and microorganisms, is used in the synthesis of various medically pivotal antiepileptic drugs and antituberculosis compounds. l-Homoalanine can be synthesized by different enzymatic approaches. In this article, the synthesis of l-homoalanine from l-methionine was explored by coimmobilization of Aspergillus flavipes l-methioninase (AfMETase) and glutamate dehydrogenase (GDH) on polyacrylamide and chitosan. Polyacrylamide coimmobilized AfMETase and GDH displayed a maximum reactivity for the synthesis of homoalanine from l-methionine. The chitosan-coimmobilized AfMETase and GDH retain about 70% of their initial activity of l-homoalanine production by the fifth catalytic reusability cycle as compared with 50% for polyacrylamide coimmobilizate. Catalytic conditions were optimized for the maximum yield of homoalanine. Homoalanine was purified by cationic and anionic chromatographs and the proton nuclear magnetic resonance (H-NMR) analysis of the lyophilized sample displayed a unique chemical structure identical to the authentic homoalanine. Using dependable dual action of AfMETase and GDH immobilized on a solid support is a novel approach for in vitro enzymatic synthesis of l-homoalanine from l-methionine, and the immobilized enzymes can be reused many times without any significant loss of their activities.

Resistance to first-line tuberculosis drugs in three cities of Nigeria

OBJECTIVES

To determine the levels of resistance to first-line tuberculosis drugs in three cities in three geopolitical zones in Nigeria.

METHODS

A total of 527 smear-positive sputum samples from Abuja, Ibadan and Nnewi were cultured on BACTEC- MGIT 960. Drug susceptibility tests (DST) for streptomycin, isoniazid, rifampicin and ethambutol were performed on 428 culture-positive samples on BACTEC-MGIT960.

RESULTS

Eight per cent of the specimens cultured were multi-drug-resistant Mycobacterium tuberculosis (MDR-TB) with varying levels of resistance to individual and multiple first-line drugs. MDR was strongly associated with previous treatment: 5% of new and 19% of previously treated patients had MDR-TB (OR 4.1 (95% CI 1.9-8.8), P = 0.001) and with young adult age: 63% of patients with and 38% without MDR-TB were 25-34 years old (P = 0.01). HIV status was documented in 71%. There was no association between MDR-TB and HIV coinfection (P = 0.9) and gender (P > 0.2 for both).

CONCLUSIONS

MDR-TB is an emerging problem in Nigeria. Developing good quality drug susceptibility test facilities, routine monitoring of drug susceptibility and improved health systems for the delivery of and adherence to first- and second-line treatment are imperative to solve this problem.

Clinico-pathological profile of acute promyelocytic leukaemia at Al-Amal Oncology-Haematology Centre, Qatar

This cases series describes the profile of adult patients with acute promyelocytic leukaemia (APt) at a referral hospital in Qatar. Of 34 acute myeloid leukaemia (AML) cases diagnosed, 11(32%) were classified as APt. Disseminated intravascular coagulation was common at presentation (91%). Severe thrombocytopenia was seen in 73%, leukocytosis in 55% and severe anaemia in 45%. Only 2 patients were of the classic hypergranular type. In the remaining 9 patients, 3 morphological subtypes were recognized: microgranular variant (6 patients), hyperbasophilic (2 patients) and regular nuclear outline M3r (1 patient). Translocation t(15;17) was detected in 63% of cases. APL constitutes a high proportion of AML cases in Qatar, with considerable morphological heterogeneity and a oredominance of APL variants with unfavourable oresenting features.

Factors associated with poor tuberculosis treatment outcome in the Southern Region of Ethiopia

SETTING

Tuberculosis (TB) treatment centres in southern Ethiopia.

OBJECTIVES

To describe the outcomes of patients registered for anti-tuberculosis treatment and to identify factors associated with poor treatment outcome.

DESIGN

Retrospective audit of patients registered from 2002 to 2007. Patients were categorised as having successful (cured or completed treatment) or poor treatment outcome (failed treatment, defaulted or died). Logistic regressions were used to identify risk factors for poor outcome.

RESULTS

A total of 6547 patients (55.6% male, 44.4% female) with a mean age of 27.5 years were registered for treatment; 2873 (43.9%) were smear-positive, 2493 (30.1%) smear-negative and 1157 (17.7%) had extra-pulmonary TB. Most (n = 6033, 92%) were new cases; 4900 (74.8%) had a successful and 1095 (16.7%) a poor treatment outcome. Of those with a poor outcome, 667 (60.9%) patients defaulted, 404 (36.9%) died and 24 (2.2%) failed treatment. Attending the regional capital health centre (aOR 2.09, 95%CI 1.85-2.69), being on retreatment (aOR 2.07, 95%CI 1.47-2.92), having a positive smear at the second month follow-up (aOR 1.68, 95%CI 1.07-2.63), having smear-negative pulmonary TB (aOR 1.62, 95%CI 1.4-1.86), age >55 years (aOR 1.44, 95%CI 1.12-1.86) and being male (aOR 1.24, 95%CI 1.09-1.42) were independent risk factors for poor outcome.

CONCLUSION

Treatment outcome was suboptimal and targeted measures should be considered to reduce the rate of poor treatment outcome among high-risk groups.

Direct patient costs associated with tuberculosis diagnosis in Yemen and Nepal

BACKGROUND

The diagnosis of TB requires multiple visits. Reducing the number of visits for diagnosis could make the process more accessible, with significant savings to the patients.

OBJECTIVE

To describe direct costs incurred by patients consulting TB diagnostic centres.

METHOD

Adults with cough >3 weeks' duration were interviewed using structured questionnaires in Yemen and Nepal to quantify their expenses.

RESULTS

A total of 456 adults were interviewed. Most patients were accompanied, and 20% were smear-positive. Patients in Nepal were more likely to be male, to live in urban areas and were older (123/206 [60%], 152 [74%] and mean age 41 years) than in Yemen (120/250 [48%], 114 [36%] and mean age 35 years). Although most patients from rural areas stayed with relatives, their overall expenses were higher than for patients from urban areas. Clinic fees represented the highest expenditure in both countries, and rural patients paid more than urban patients in both settings. The expenses for diagnosis were equivalent to 1 week of the national income per capita.

CONCLUSION

Patients incur considerable costs for diagnosis, and clinic fees represent a substantial component of these costs. Patients requiring investigations for TB should be able to access diagnostic services free of charge.

Validation of bleach-treated smears for the diagnosis of pulmonary tuberculosis

SETTING

Health centres in Awassa, southern Ethiopia.

DESIGN

Consecutive patients visiting health centre laboratories for the evaluation of suspected pulmonary tuberculosis (TB) between June and September 2006 were investigated. On-the-spot, morning and second on-the-spot sputum samples were pooled for each patient. Direct smears were stained with hot Ziehl-Neelsen (ZN) technique and aliquots cultured for mycobacteria on Löwenstein-Jensen media. The remaining sputum was treated with household bleach, aliquoted and processed with short-term digestion, centrifugation and sedimentation techniques, and stained with ZN.

RESULTS

Acid-fast bacilli were detected in respectively 126 (25%), 141 (28%), 169 (34%) and 198 (40%) of the 497 pooled sputum samples processed by the direct, short-term, sedimentation and centrifugation techniques (P < 0.001). The sensitivity of the direct, short-term, sedimentation and centrifugation techniques was respectively 51.1%, 53.2%, 57.6% and 63.6%. The difference between the direct smear and centrifugation (P < 0.001) or sedimentation (P < 0.005) methods was significant. The specificity of the direct, short-term digestion, sedimentation and centrifugation techniques was respectively 97%, 93%, 86.5% and 80.8%.

CONCLUSIONS

Bleach treatment of sputum and centrifugation significantly improves the sensitivity of smear microscopy for the diagnosis of TB in a health centre in a high TB burden area. It is more sensitive, but possibly less specific, than other bleach methods.

Rhino-orbital zygomycosis secondary to Rhizopus oryzae in a renal transplant recipient successfully treated with liposomal amphotericin B

Rhino-orbital zygomycosis is usually an aggressive, fulminant and, at times, fatal disease that requires urgent medical and surgical treatment. We report a case of rhino-orbital zygomycosis caused by Rhizopus oryzae that developed in a 41-year-old male renal transplant recipient. He was diagnosed in the early post transplant period after anti-rejection therapy. The infection was successfully managed with liposomal amphotericin B and functional endoscopic sinus surgery.

Same-day smears in the diagnosis of tuberculosis

OBJECTIVE

To assess the feasibility of completing the diagnosis of tuberculosis (TB) in 1 day by collecting only on-the-spot specimens.

METHODS

Individuals with suspected TB attending district hospitals in Abuja submitted three sputum samples for routine diagnosis (the standard approach). One additional sample was collected 1 h after the first sputum (the same-day approach). One sputum sample was cultured. Blood samples were tested for HIV.

RESULTS

Two hundred and twenty-four patients with chronic cough had 135/672 (20%) positive on-the-spot smears and 47/224 (21%) positive morning smears. The same-day and internationally recommended approaches identified 44 and 45 of the 78 patients with positive cultures, respectively. 106/194 (55%) patients were HIV positive. Only 9-11% of their smears were positive compared with 30-32% for HIV negatives (P < 0.01).

CONCLUSION

It could be possible to diagnose TB in a single day by examining two spot specimens, but the feasibility needs to be confirmed on a larger scale.

Effect of reactive vaccination on meningitis epidemics in Southern Ethiopia

OBJECTIVES

To describe the duration and seasonality of meningitis epidemics in Southern Ethiopia and estimate the proportion of cases prevented by vaccination in order to assess the efficacy of current control strategies.

METHODS

A descriptive study of epidemics occurring from 1999 to 2004. The number of cases reported in 24 districts undergoing vaccination campaigns was compared to 36 districts not receiving vaccines or where vaccines had been deployed in the zone.

RESULTS

Sixty epidemics reporting a total of 5806 cases were identified. The duration of the epidemics ranged from 1 to 26 weeks with 45% lasting < or = 6 weeks. Forty-one epidemics reached the WHO epidemic threshold. Seventy-one percent of the cases reported from vaccinated areas occurred in the first 6 weeks compared to 62% in unvaccinated areas and 82% for districts where vaccines had been used in the zone.

CONCLUSIONS

The majority of epidemics had a short duration limiting the potential to implement current vaccines effectively. Delivering vaccine to areas adjacent to an epidemic seems to increase their efficacy, however the size of this additional area needs to be better defined.

Short-term bleach digestion of sputum in the diagnosis of pulmonary tuberculosis in patients co-infected with HIV

The bleach digestion of sputum may improve the yield of smear microscopy but has not been validated in patients with HIV. Therefore we assessed the performance of bleach-digested smear microscopy among patients with HIV. One thousand three hundred and twenty one patients with chronic cough submitted three sputum samples for direct smear microscopy and were offered HIV tests. One sample was selected for a bleach-digested smear and another one was cultured. Patients were classified as having 'definite' (>or=2 positive smears), 'very likely' (smear-negative, culture- positive), 'less likely' (one smear-positive, culture-negative) and 'unlikely' (smear and culture negative) tuberculosis (TB). In all, 566/1045 (54%) patients were HIV positive and 731/1186 (62%) were culture positive. The digested smears were positive in 123/125 (98%) 'definite', 4/118 (3%) 'very likely' and 1/174 'unlikely' TB patients with HIV and in 125/127 (98%) 'definite', 2/74 (3%) 'very likely', 4/4 'less likely' and 2/127 'unlikely' TB without HIV. Three direct smears identified 252 (57%) and one digested smear 254 (57%) of the 444 patients with 'definite' or 'very likely' TB. One bleach-digested smear performed similarly to three direct smears. Both methods were less sensitive in HIV-positive patients. Further studies are needed to compare the performance of the two methods under operational conditions.

Bleach-digested sputum smears for the diagnosis of TB in HIV-infected individuals

We describe the performance of bleach-digested Zeihl-Neelsen (ZN) smears in TB suspects with/without HIV. In total, 51 (26%) and 62 (31%) out of the first 198 spot and digested smears were positive. Seven of the 30 HIV-positive patients had TB and their ZN smears were negative, scanty or 1 +. Six of seven digested smears were scanty. Forty-two of 115 HIV-negative patients had TB. Eleven (26%) of their digested smears were negative, 12 (29%) scanty and 19 (45%) positive. Despite the lower bacilli numbers of HIV-positive patients, the technique had sensitivity and specificity similar to that in HIV-negative patients.

Ten-year experiences of the tuberculosis control programme in the southern region of Ethiopia

SETTINGS

The tuberculosis control programme, southern region of Ethiopia.

OBJECTIVE

To assess the impact of the expansion of the DOTS strategy on tuberculosis (TB) case finding and treatment outcome.

DESIGN

Reports of TB patients treated since the introduction of DOTS in the region were reviewed. Patients were diagnosed and treated according to World Health Organization (WHO) recommendations. Case notification and treatment outcome reports were compiled quarterly at district level and submitted to the regional programme.

RESULTS

Of 136,572 cases registered between 1995 and 2004, 47% were smear-positive, 25% were smear-negative and 28% had extra-pulmonary tuberculosis (EPTB). In 2004, 94% of the health institutions were covered by DOTS. Between 1995 and 2004, the smear-positive case notification rate increased from 45 to 143 per 100,000 population, the case detection rate from 22% to 45%, and the treatment success rate from 53% to 85%. The default and failure rates decreased from 26% to 6% and from 7% to 1%, respectively.

DISCUSSION

There was a steady increase in the treatment success rate with the decentralisation of DOTS. Although 94% coverage was achieved after 10 years, the stepwise scale-up was important in securing resources and dealing with challenges. The programme achieved 85% treatment success; however, with the current low case detection rate (45%), the 70% WHO target seems unachievable in the absence of alternative case-finding mechanisms.

Evaluation of the meningitis epidemics risk model in Africa

Meningitis epidemics have a strong environmental component in Africa with the most severe epidemics occurring in the Sahelian region known as the Meningitis Belt. The objective of this study is to evaluate an ecological model based on absolute humidity and land cover type to predict the location of these epidemics. The risk model is evaluated prospectively based on epidemics occurring in Africa from January 2000 to April 2004. Seventy-one epidemics occurred during this time period affecting 22% of continental African districts. The model predicted their location with a sensitivity of 88%. The evaluation also suggests that epidemics may be extending south of the Sahel, which is consistent with environmental changes in the region. This model could be used to select priority areas for the introduction of the newly developed conjugate meningococcal vaccines. Further studies are needed to enhance our understanding of the complex relationship between meningitis epidemics and the environment.

A one-day method for the diagnosis of pulmonary tuberculosis in rural Ethiopia

Smear diagnosis of pulmonary tuberculosis (PTB) requires three sputum examinations over 2 days. We evaluated the performance of two sputum specimens obtained on a single day (the second specimen submitted 1 h after the first) against the standard 2-day method in rural Ethiopia. A total of 243 suspects were enrolled; 52 had confirmed PTB: 49 (94%) were detected by the same-day method and 51 (98%) by the standard method (P > 0.5). The same-day approach would reduce the number of visits required for diagnosis, save resources for the health system and the patient, and ultimately improve case detection in poorer countries.

Microbiological validation of smear microscopy after sputum digestion with bleach; a step closer to a one-stop diagnosis of pulmonary tuberculosis

BACKGROUND

Smear microscopy is relatively insensitive for the diagnosis of TB. The digestion of sputum with household bleach prior to smear preparation has been reported to improve its sensitivity. This method has not been validated.

METHODS

Seven hundred and fifty six patients with symptoms suggestive of pulmonary TB (PTB) were asked to submit 3 sputum specimens for direct microscopy. One specimen was selected at random for culture and another specimen was digested to prepare a further smear. The WHO case definition (>or=2 positive smears or one positive smear and positive culture) was used to compare the sensitivity and specificity of the smears.

FINDINGS

Four hundred and fifty five (60%) patients were culture-positive. Of these, 235 (31%) had "definite" PTB and 223 (29%) "very likely" PTB (smear-negative, culture-positive). The WHO case definition identified 51% (235/458) of the patients with "definite" or "very likely" PTB. One digested smear detected 219 (93%) of the 235 patients with "definite" PTB and 10 patients with "very likely" PTB (sensitivity (95%CI) 50% (45-55%); specificity 99% (97-100%)). The positive and negative predictive values for one digested smear were 98% (95-99%) and 56% (52-60%) respectively, which were not different (p>0.5) to the WHO case definition (100% and 57%, respectively).

INTERPRETATION

One bleach-digested smear is as sensitive and specific as the WHO case definition for the diagnosis of PTB.

Prevalence of smear-positive pulmonary tuberculosis in a rural district of Ethiopia

SETTING

A rural district in Southern Ethiopia.

OBJECTIVE

To estimate the prevalence of smear-positive pulmonary tuberculosis (TB).

DESIGN

In this cross-sectional study, adults aged >14 years were surveyed by home-to-home visit, and asked about cough of > or = 2 weeks with or without sputum, chest pain or difficulty in breathing. Symptomatic suspects submitted three sputum samples for standard smear microscopy.

RESULTS

Of 16697 adults surveyed, 436 (2.6%) were symptomatic and submitted sputum samples. Thirteen (3%) were positive for acid-fast bacilli, and the prevalence of smear-positive TB was 78 per 100 000 population (95%CI 36-120). Twenty-four smear-positive cases identified through the existing health care delivery were on anti-tuberculosis medication at the time of the survey. The ratio of smear-positive cases on treatment to those newly detected by the survey was 2:1.

CONCLUSION

The prevalence of TB in this rural setting was unexpectedly low. For every two cases of smear-positive TB on treatment, there was one undetected infectious case in the community. However, as our screening technique did not allow detection of cases who did not report symptoms, the true prevalence may have been underestimated.

Comparison of scanty AFB smears against culture in an area with high HIV prevalence

To verify among tuberculosis (TB) suspects attending hospitals in Abuja, Nigeria, if sputum smears graded as scanty are false-positive, sputum smears from 1068 patients were graded with the International Union Against Tuberculosis and Lung Disease classification. One specimen was cultured. Eight hundred and twenty-four (26%) smears were positive, 137 (4%) scanty and 2243 negative. Of 1068 cultures, 680 (64%) were positive. One hundred and thirty (95%) scanty and 809 (98%) positive smears were culture-positive. Twelve of 18 patients with a single scanty smear and 51 of 52 with > or = 2 scanty smears were culture-positive. Fewer than < 5% scanty results, < 1% of the patients treated for TB, are false-positive.

Efficacy and safety of short-term bleach digestion of sputum in case-finding for pulmonary tuberculosis in Ethiopia

BACKGROUND

In many settings, the diagnosis of pulmonary tuberculosis depends on sputum microscopy. However, this technique has low sensitivity. We studied the efficacy and safety of sputum digestion with bleach prior to Ziehl-Neelsen (ZN) staining.

METHODS

Positive sputum smears were assessed for staining quality and viability of mycobacteria after varying bleaching times. Two hundred smears were then prepared from the first, second and third sputum sample of tuberculosis suspects. Equal amounts of 5% bleach were added to the remaining first sputum and ZN smears were prepared.

FINDINGS

Optimal quality and staining was achieved with 30-45 min of bleaching. No growth was observed from positive samples after 15 min. Bleached specimens had 26% (52/200) positivity compared to 17.5% (35/ 200) of unbleached smears (P < 0.001). The bleached smears had 92.3% sensitivity, 93.4% specificity, 78.3% and 97.7% positive and negative predictive values, respectively, against a case definition. Ten patients failed to submit a second or third sputum. Six patients were positive on either the standard or bleach-digested smears, or both.

INTERPRETATION

Bleach digestion is simple, cheap and kills mycobacteria. Its positivity rate is as good as three standard smears. This method has the potential to improve over-burdened services in developing countries.

Comparison of screening methods for anaemia in pregnant women in Awassa, Ethiopia

Screening for anaemia in pregnancy is essential for implementing and monitoring effective antenatal programmes. We compared the diagnostic accuracy of invasive and non-invasive screening methods in a cross-sectional survey of 403 pregnant women attending an urban health centre in Awassa, southern Ethiopia. Overall anaemia prevalence [haemoglobin (Hb): <11 g/dl] was 15.1% (95% CI: 12.1-19.9), mild anaemia (Hb: 10-10.9 g/dl) 10.4%, moderate anaemia (Hb: 7-9.9 g/dl) 4.2% and severe anaemia (Hb < 7 g/dl) 0.3%. Sensitivity, specificity and predictive values of conjunctival pallor and the WHO Hb colour scale were calculated for Hb cut-off points <11, <10 and <9 g/dl. All methods in combination with the symptoms and complaints reported by the mothers were entered into a predictive scoring system. None of the methods tested or models predicted anaemia with suitable accuracy in this population. The diagnosis of anaemia based on clinical signs and symptoms remains unreliable despite attempts to develop predictive models.