Scielo RSS <![CDATA[African Journal of Laboratory Medicine]]> http://www.scielo.org.za/rss.php?pid=2225-201020180002&lang=pt vol. 7 num. 2 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Antimicrobial resistance surveillance in Africa: Successes, gaps and a roadmap for the future</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200001&lng=pt&nrm=iso&tlng=pt <![CDATA[<i><b>Clostridium difficile</b></i><b> in patients attending tuberculosis hospitals in Cape Town, South Africa, 2014-2015</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200002&lng=pt&nrm=iso&tlng=pt BACKGROUND: Diarrhoea due to Clostridium difficile infection (CDI) poses a significant burden on healthcare systems around the world. However, there are few reports on the current status of the disease in sub-Saharan Africa. OBJECTIVES: This study examined the occurrence of CDI in a South African population of tuberculosis patients, as well as the molecular epidemiology and antibiotic susceptibility profiles of C. difficile strains responsible for disease. METHODS: Toxigenic C. difficile in patients with suspected CDI attending two specialist tuberculosis hospitals in the Cape Town area were detected using a PCR-based diagnostic assay (Xpert®C. difficile). C. difficile strains isolated from PCR-positive specimens were characterised by ribotyping, multilocus variable-number tandem-repeat analysis and antibiotic susceptibility testing. RESULTS: The period prevalence of CDI was approximately 70.07 cases per 1000 patient admissions. Strains belonging to ribotype 017 (RT017) made up over 95% of the patient isolates and all of them were multi-drug resistant. Multilocus variable-number tandem-repeat analysis revealed several clusters of highly related C. difficile RT017 strains present in tuberculosis patients in several wards at each hospita.l CONCLUSION: Tuberculosis patients represent a population that may be at an increased risk of developing CDI and, in addition, may constitute a multi-drug resistant reservoir of this bacterium. This warrants further investigation and surveillance of the disease in this patient group and other high-risk patient groups in sub-Saharan Africa. <![CDATA[<b>Antibiotic resistance trends of ESKAPE pathogens in Kwazulu-Natal, South Africa: A five-year retrospective analysis</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200003&lng=pt&nrm=iso&tlng=pt BACKGROUND: To combat antimicrobial resistance, the World Health Organization developed a global priority pathogen list of antibiotic-resistant bacteria for prioritisation of research and development of new, effective antibiotics. OBJECTIVE: This study describes a five-year resistance trend analysis of the ESKAPE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp., from Kwazulu-Natal, South Africa. METHODS: This retrospective study used National Health Laboratory Services data on 64 502 ESKAPE organisms isolated between 2011 and 2015. Susceptibility trends were ascertained from minimum inhibitory concentrations and interpreted using Clinical and Laboratory Standards Institute guidelines. RESULTS: S. aureus was most frequently isolated (n = 24, 495, 38%), followed by K. pneumoniae (n = 14, 282, 22%). Decreasing rates of methicillin-resistant S. aureus (28% to 18%, p < 0.001) and increasing rates of extended spectrum beta-lactamase producing K. pneumoniae (54% to 65% p < 0.001) were observed. Carbapenem resistance among K. pneumoniae and Enterobacter spp. was less than 6% during 2011-2014, but increased from 4% in 2014 to 16% in 2015 (p < 0.001) among K. pneumoniae. P. aeruginosa increased (p = 0.002), but resistance to anti-pseudomonal antimicrobials decreased from 2013 to 2015. High rates of multi-drug resistance were observed in A. baumanni (&gt; 70%). CONCLUSION: This study describes the magnitude of antimicrobial resistance in KwaZulu-Natal and provides a South African perspective on antimicrobial resistance in the global priority pathogen list, signalling the need for initiation or enhancement of antimicrobial stewardship and infection control measures locally. <![CDATA[<b>Multi-drug resistant <i>Mycobacterium tuberculosis</i> in Port Harcourt, Nigeria</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200004&lng=pt&nrm=iso&tlng=pt BACKGROUND: In past years, much focus has been on tackling the scourge and spread of tuberculosis worldwide. The recent emergence of multi-drug resistant (MDR) tuberculosis has, however, negatively threatened progress made so far. Nigeria ranks fourth out of the 22 high tuberculosis burden countries in the world and has the highest burden of tuberculosis in Africa. It is therefore necessary to monitor the MDR tuberculosis situation in the country. OBJECTIVES: This study set out to assess the proportions of MDR tuberculosis in patients attending six directly observed treatment short-course centres in Port Harcourt, Nigeria, from October 2015 to October 2016. METHODS: Six hundred and nine participants between the ages of 18 and 75 years were enrolled in this study and comprised suspected and newly diagnosed tuberculosis cases. Sputum samples obtained from the participants were screened for the presence of Mycobacterium tuberculosis using standard culture and phenotypic biochemical techniques, and drug susceptibility testing was carried out using the 1% proportion conventional method. RESULTS: Of the 609 participants enrolled, 30 (4.9%) were confirmed as M. tuberculosis-positive cases. A high prevalence of drug resistant tuberculosis was noted in this study (14/30, 46.7%), with 26.7% of isolates resistant to streptomycin. MDR tuberculosis, defined as being resistant to isoniazid and rifampicin, was detected in only one case (3.3%). CONCLUSION: This study reports a low rate of MDR tuberculosis and contributes to the sparse data on drug resistant tuberculosis in Nigeria. <![CDATA[<b>Differential infectivity of gametocytes after artemisinin-based combination therapy of uncomplicated falciparum malaria</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200005&lng=pt&nrm=iso&tlng=pt BACKGROUND: Most malaria-endemic countries use artemisinin-based combination therapy (ACT) as their first-line treatment. ACTs are known to be highly effective on asexual stages of the malaria parasite. Malaria transmission and the spread of resistant parasites depend on the infectivity of gametocytes. The effect of the current ACT regimens on gametocyte infectivity is unclear. OBJECTIVES: This study aimed to determine the infectivity of gametocytes to Anopheles gambiae following ACT treatment in the field. METHODS: During a randomised controlled trial in Bougoula-Hameau, Mali, conducted from July 2005 to July 2007, volunteers with uncomplicated malaria were randomised to receive artemether-lumefantrine, artesunate-amodiaquine, or artesunate-sulfadoxine/pyrimethamine. Volunteers were followed for 28 days, and gametocyte carriage was assessed. Direct skin feeding assays were performed on gametocyte carriers before and after ACT administration. RESULTS: Following artemether-lumefantrine treatment, gametocyte carriage decreased steadily from Day 0 to Day 21 post-treatment initiation. In contrast, for the artesunate-amodiaquine and artesunate-sulfadoxine/pyrimethamine arms, gametocyte carriage increased on Day 3 and remained constant until Day 7 before decreasing afterward. Mosquito feeding assays showed that artemether-lumefantrine and artesunate-amodiaquine significantly increased gametocyte infectivity to Anopheles gambiae sensu lato (s.l.) (p < 10−4), whereas artesunate-sulfadoxine/pyrimethamine decreased gametocyte infectivity in this setting (p = 0.03). CONCLUSION: Different ACT regimens could lead to gametocyte populations with different capacity to infect the Anopheles vector. Frequent assessment of the effect of antimalarials on gametocytogenesis and gametocyte infectivity may be required for the full assessment of treatment efficacy, the potential for spread of drug resistance and malaria transmission in the field. <![CDATA[<b>An overview of antimicrobial resistance surveillance among healthcare-associated pathogens in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200006&lng=pt&nrm=iso&tlng=pt Healthcare-associated infections are a serious public health concern resulting in morbidity and mortality particularly in developing countries. The lack of information from Africa, the increasing rates of antimicrobial resistance and the emergence of new resistance mechanisms intensifies this concern warranting the need for vigorous standardised surveillance platforms that produce reliable and accurate data which can be used for addressing these concerns. The implementation of national treatment guidelines, policies, antimicrobial stewardship programmes and infection prevention and control practices within healthcare institutions require a platform from which it can draw information and direct its approach. In this review, the importance of standardised surveillance systems, the challenges faced in the application of a surveillance system and the condition (existence and nonexistence) of such systems in African countries is discussed. This review also reports on some South African data. <![CDATA[<b>Drug resistant tuberculosis in Africa: Current status, gaps and opportunities</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200007&lng=pt&nrm=iso&tlng=pt BACKGROUND: The World Health Organization End TB Strategy targets for 2035 are ambitious and drug resistant tuberculosis is an important barrier, particularly in Africa, home to over a billion people. OBJECTIVE: We sought to review the current status of drug resistant tuberculosis in Africa and highlight key areas requiring improvement. METHODS: Available data from 2016 World Health Organization global tuberculosis database were extracted and analysed using descriptive statistics. RESULTS: The true burden of drug resistant tuberculosis on the continent is poorly described with only 51% of countries having a formal survey completed. In the absence of this data, modelled estimates were used and reported 92 629 drug resistant tuberculosis cases with 42% of these occurring in just two countries: Nigeria and South Africa. Of the cases estimated, the majority of patients (70%) were not notified, representing 'missed cases'. Mortality among patients with multi-drug resistant tuberculosis was 21%, and was 43% among those with extensively drug resistant tuberculosis. Policies on the adoption of new diagnostic tools was poor and implementation was lacking. A rifampicin result was available for less than 10% of tuberculosis cases in 23 of 47 countries. Second-line drug resistance testing was available in only 60% of countries. The introduction of the short multi-drug resistant tuberculosis regimen was a welcome development, with 40% of countries having implemented it in 2016. Bedaquiline has also been introduced in several countries. CONCLUSION: Drug resistant tuberculosis is largely missed in Africa and this threatens prospects to achieve the 2035 targets. Urgent efforts are required to confirm the true burden of drug resistant tuberculosis in Africa. Adoption of new tools and drugs is essential if the 2035 targets are to be met. <![CDATA[<b>A systematic review of healthcare-associated infections in Africa: An antimicrobial resistance perspective</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200008&lng=pt&nrm=iso&tlng=pt BACKGROUND: Healthcare-associated infection (HCAI) is a global health challenge, not only as an issue of patient safety but also as a major driver of antimicrobial resistance (AMR). It is a major cause of morbidity and mortality with economic consequences. OBJECTIVE: This review provides an update on the occurrence of HCAI, as well as the contribution of emerging AMR on healthcare delivery in Africa. METHODS: We searched PubMed, Cochrane database, African Journals Online and Google Scholar for relevant articles on HCAI in Africa between 2010 and 2017. Preferred reporting items of systematic reviews and meta-analyses guidelines were followed for selection. Thirty-five eligible articles were considered for the qualitative synthesis. RESULTS: Of the 35 eligible articles, more than half (n = 21, 60%) were from East Africa. Klebsiella spp., Staphylococcus aureus, Escherichia coli and Pseudomonas spp. were the common pathogens reported in bloodstream infection, (catheter-associated) urinary tract infection, surgical site infection and healthcare-associated pneumonia. Among these various subtypes of HCAI, methicillin-resistant S. aureus (3.9% - 56.8%) and extended-spectrum beta-lactamase producing Gram-negative bacilli (1.9% - 53.0%) were the most reported antimicrobial resistant pathogens. CONCLUSION: This review shows a paucity of HCAI surveillance in Africa and an emergence of AMR priority pathogens. Hence, there is a need for a coordinated national and regional surveillance of both HCAI and AMR in Africa. <![CDATA[<b>Antimicrobial resistance of <i>Vibrio cholerae</i> from sub-Saharan Africa: A systematic review</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200009&lng=pt&nrm=iso&tlng=pt BACKGROUND: The World Health Assembly adopted the Global Action Plan on Antimicrobial Resistance, which includes improving the knowledge base through surveillance and research. Noteworthily, the World Health Organization has advocated a Global Antimicrobial Resistance Surveillance System to address the plan's surveillance objective, with most African countries enrolling in or after 2017. AIM: The aim of this article was to review prior data on antimicrobial resistance of Vibrio cholerae from sub-Saharan Africa with a view for future control and intervention strategies. METHODS: We used the Preferred Reporting Items for Systematic Review and Meta-Analysis (or 'PRISMA') guidelines to search the PubMed and African Journals Online databases, as well as additional articles provided by the Nigeria Centre for Disease Control, for articles reporting on the antibiotic susceptibility of V. cholerae between January 2000 and December 2017. RESULTS: We identified 340 publications, of which only 25 (reporting from 16 countries within the sub-Saharan African region) were eligible. The majority (20; 80.0%) of the cholera toxigenic V. cholerae isolates were of the serogroup O1 of the El Tor biotype with Ogawa and Inaba serotypes predominating. Resistance was predominantly documented to trimethoprim-sulphamethoxazole (50% of the studies), ampicillin (43.3% of the studies), chloramphenicol (43.3% of the studies) and streptomycin (30% of the studies). Resistance mechanisms were reported in 40% of the studies. CONCLUSION: Our results demonstrate a documented antimicrobial resistance of V. cholerae to multiple antibiotic classes, including cell wall active agents and antimetabolites with evidence of phenotypic/genotypic resistance to fluoroquinolones. <![CDATA[<b>Africa Centres for Disease Control and Prevention's framework for antimicrobial resistance control in Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200010&lng=pt&nrm=iso&tlng=pt BACKGROUND: The World Health Assembly adopted the Global Action Plan on Antimicrobial Resistance, which includes improving the knowledge base through surveillance and research. Noteworthily, the World Health Organization has advocated a Global Antimicrobial Resistance Surveillance System to address the plan's surveillance objective, with most African countries enrolling in or after 2017. AIM: The aim of this article was to review prior data on antimicrobial resistance of Vibrio cholerae from sub-Saharan Africa with a view for future control and intervention strategies. METHODS: We used the Preferred Reporting Items for Systematic Review and Meta-Analysis (or 'PRISMA') guidelines to search the PubMed and African Journals Online databases, as well as additional articles provided by the Nigeria Centre for Disease Control, for articles reporting on the antibiotic susceptibility of V. cholerae between January 2000 and December 2017. RESULTS: We identified 340 publications, of which only 25 (reporting from 16 countries within the sub-Saharan African region) were eligible. The majority (20; 80.0%) of the cholera toxigenic V. cholerae isolates were of the serogroup O1 of the El Tor biotype with Ogawa and Inaba serotypes predominating. Resistance was predominantly documented to trimethoprim-sulphamethoxazole (50% of the studies), ampicillin (43.3% of the studies), chloramphenicol (43.3% of the studies) and streptomycin (30% of the studies). Resistance mechanisms were reported in 40% of the studies. CONCLUSION: Our results demonstrate a documented antimicrobial resistance of V. cholerae to multiple antibiotic classes, including cell wall active agents and antimetabolites with evidence of phenotypic/genotypic resistance to fluoroquinolones. <![CDATA[<b>Antimicrobial resistance surveillance with whole genome sequencing in Africa: It's (about) time</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200011&lng=pt&nrm=iso&tlng=pt BACKGROUND: The World Health Assembly adopted the Global Action Plan on Antimicrobial Resistance, which includes improving the knowledge base through surveillance and research. Noteworthily, the World Health Organization has advocated a Global Antimicrobial Resistance Surveillance System to address the plan's surveillance objective, with most African countries enrolling in or after 2017. AIM: The aim of this article was to review prior data on antimicrobial resistance of Vibrio cholerae from sub-Saharan Africa with a view for future control and intervention strategies. METHODS: We used the Preferred Reporting Items for Systematic Review and Meta-Analysis (or 'PRISMA') guidelines to search the PubMed and African Journals Online databases, as well as additional articles provided by the Nigeria Centre for Disease Control, for articles reporting on the antibiotic susceptibility of V. cholerae between January 2000 and December 2017. RESULTS: We identified 340 publications, of which only 25 (reporting from 16 countries within the sub-Saharan African region) were eligible. The majority (20; 80.0%) of the cholera toxigenic V. cholerae isolates were of the serogroup O1 of the El Tor biotype with Ogawa and Inaba serotypes predominating. Resistance was predominantly documented to trimethoprim-sulphamethoxazole (50% of the studies), ampicillin (43.3% of the studies), chloramphenicol (43.3% of the studies) and streptomycin (30% of the studies). Resistance mechanisms were reported in 40% of the studies. CONCLUSION: Our results demonstrate a documented antimicrobial resistance of V. cholerae to multiple antibiotic classes, including cell wall active agents and antimetabolites with evidence of phenotypic/genotypic resistance to fluoroquinolones. <![CDATA[<b>The role of connected diagnostics in strengthening regional, national and continental African disease surveillance</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200012&lng=pt&nrm=iso&tlng=pt The Africa Centres for Disease Control and Prevention (Africa CDC) and World Health Organization (WHO) Regional Office for Africa (AFRO) are building a global health security programme that aims to strengthen both regional and national health through networked, collaborative efforts to improve infectious disease and antimicrobial resistance surveillance. To achieve this, the Africa CDC is calling for a data-sharing platform that can be leveraged across member states and disease areas, strengthening the ability to collate, analyse and interpret data, and to respond with the appropriate action. Although numerous disease intelligence and surveillance systems exist, they are plagued with inaccurate or untimely data. We contend, furthermore, that it was this lack of data quality - and not the lack of surveillance systems or networks - that prevented the global community from acting earlier in response to the Ebola outbreak in 2014-2016. The new field of 'connected diagnostics' is one solution to this concern, as it automates data collection directly from the diagnostic instruments to multiple levels of stakeholders for real-time decision-making and policy response. This article details how the intervention of 'connected diagnostics' could solve the primary underlying failure in existing surveillance systems - the lack of accurate and timely data - to enable difficult political decisions earlier. The use of connectivity solutions can enable critical health and operational data to empower the Africa CDC, regional hubs, and each country with a consistent and automated data feed while still maintaining country privacy and controls. <![CDATA[<b>Leveraging donor support to develop a national antimicrobial resistance policy and action plan: Ghana's success story</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200013&lng=pt&nrm=iso&tlng=pt BACKGROUND: To mitigate the increasing trend of antimicrobial drug resistance (AMR), the Global Action Plan (GAP) on AMR was adopted at the 68th World Health Assembly in May 2015. Subsequently, member countries were encouraged to mirror the five key strategic objectives of GAP to develop their respective National Action Plans (NAPs) by 2017. Country-specific data on AMR is, however, critical for a comprehensive NAP that will inform policy and also anchor all the objectives of GAP. Systematic reviews have been suggested by some authors to generate relevant data to inform NAP development. OBJECTIVES: This article highlights Ghana's success story in the development of its AMR policy documents and how it could further be implemented through donor support. METHODS: Literature and desk review of the activities of Ghana's National Platform on Antimicrobial Resistance leading to the development of the NAP and AMR policy was done. RESULTS: Ghana launched its NAP together with the accompanying policy document in April 2018. Country-specific data, which guided these documents, were obtained by leveraging donor support activities through the National Platform on Antimicrobial Resistance. CONCLUSION: Ghana's success story on the development of AMR policy documents is pivoted on a strong political will and the leveraging of donor support for specific activities. <![CDATA[<b>Antimicrobial resistance surveillance in Ethiopia: Implementation experiences and lessons learned</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200014&lng=pt&nrm=iso&tlng=pt INTRODUCTION: Antimicrobial resistance (AMR) poses a global threat. High levels of AMR to commonly used antibiotics have been reported in East Africa. A situation analysis of AMR in Ethiopia also indicated high resistance levels. To prevent and contain AMR, Ethiopia established a national surveillance network. OBJECTIVES: This article describes the steps taken to prioritise AMR and establish the National Antimicrobial Resistance Surveillance System in Ethiopia, as well as present the challenges and lessons learned through implementation. METHODS: In April 2017, Ethiopia had developed and approved the National AMR Surveillance Plan for laboratory-based AMR surveillance. The World Health Organization recommendations and Ethiopias's current microbiology capacity were used to prioritise organisms for reporting. The surveillance system is comprised of a network linking the national reference laboratory with surveillance sentinel sites. Roll-out of the AMR surveillance network occurred in three phases in order to ensure successful implementation. RESULTS: Electronic capture and transmission of data, supply chain for the microbiology laboratory and communication problems were challenges observed after implementation started. Support from Ethiopian Public Health Institute focal persons for data entry, regular scheduled communication establishment and procurement of supplies by the American Society for Microbiology were some of the measures taken to address the challenges. CONCLUSION: Ethiopia has demonstrated that setting up AMR surveillance in lower resource settings is possible with strong leadership and stakeholder engagement. <![CDATA[<b>Need for better adherence to optimal incubation temperature for quality laboratory diagnostics and antibiotic resistance monitoring</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200015&lng=pt&nrm=iso&tlng=pt INTRODUCTION: Antimicrobial resistance (AMR) poses a global threat. High levels of AMR to commonly used antibiotics have been reported in East Africa. A situation analysis of AMR in Ethiopia also indicated high resistance levels. To prevent and contain AMR, Ethiopia established a national surveillance network. OBJECTIVES: This article describes the steps taken to prioritise AMR and establish the National Antimicrobial Resistance Surveillance System in Ethiopia, as well as present the challenges and lessons learned through implementation. METHODS: In April 2017, Ethiopia had developed and approved the National AMR Surveillance Plan for laboratory-based AMR surveillance. The World Health Organization recommendations and Ethiopias's current microbiology capacity were used to prioritise organisms for reporting. The surveillance system is comprised of a network linking the national reference laboratory with surveillance sentinel sites. Roll-out of the AMR surveillance network occurred in three phases in order to ensure successful implementation. RESULTS: Electronic capture and transmission of data, supply chain for the microbiology laboratory and communication problems were challenges observed after implementation started. Support from Ethiopian Public Health Institute focal persons for data entry, regular scheduled communication establishment and procurement of supplies by the American Society for Microbiology were some of the measures taken to address the challenges. CONCLUSION: Ethiopia has demonstrated that setting up AMR surveillance in lower resource settings is possible with strong leadership and stakeholder engagement. <![CDATA[<b>Diagnosis of rifampicin-resistant tuberculosis: Discordant results by diagnostic methods</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-20102018000200016&lng=pt&nrm=iso&tlng=pt The performance of the Xpert© MTB/RIF and MTBDRplus assays for the detection of rifampicin resistant Mycobacterium tuberculosis was compared to culture-based drug susceptibility testing in 30 specimens with rifampicin-resistant and rifampicin-indeterminate Xpert MTB/RIF results collected between March 2012 and March 2014. Xpert MTB/RIF and MTBDRplus were 100% sensitive and 100% concordant for rifampicin resistance detection, but 3 of 13 samples (23%) positive for rifampicin resistance on Xpert MTB/RIF and MTBDRplus were negative for rifampicin resistance on mycobacteria growth indicator tube drug susceptibility testing. Specificity was 72% for Xpert MTB/RIF and 80% for MTBDRplus. Positive predictive value for Xpert MTB/RIF for multidrug resistant tuberculosis was 47.8% for new patients and 77.8% for previously treated patients; negative predictive value was 100% for both new and previously treated patients. The discordant rifampicin resistance test results indicate a need to fully characterise circulating rifampicin resistant Mycobacterium tuberculosis strains in Zambia and to inform the development of guidelines for decision-making in relation to diagnosis of drug-resistant tuberculosis.