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F A Drobniewski

Publications and source records attributed to F A Drobniewski.

At least 19 recordsLinked to original sources
PubMed2006

Recommended standards for modern tuberculosis laboratory services in Europe.

The principles underpinning these standards are that any tuberculosis laboratory-based diagnostic procedure should be performed by appropriately trained staff, working to standardised operating procedures in appropriately equipped and safe laboratories, against clear national and international proficiency and quality standards. Quality should be the pre-eminent criteria, not cost. The standards are technologically feasible, but initially may not be within the financial capacity of all laboratories. There is a requirement for government and international donors to adequately fund an appropriate safe infrastructure to enable staff to deliver accurate and timely results at whatever level of activity they are performing. There is a need for national reference laboratories to train a new cadre of mycobacterial laboratory experts. This will require the funding of appropriate individuals at these centres to train and assist in the implementation of good laboratory practice and evaluation to build sustainable capacity. Further operational research is needed to establish the optimal configuration of new technologies to determine isoniazid, rifampicin and second-line drug susceptibility in mycobacterial cultures and also, increasingly, directly on specimens. Improved integration of laboratory medicine as a core part of all tuberculosis programmes is needed to achieve and maximise the potential of new developments.

Clinical Laboratory Techniques↗
PubMed2005

The use of macroarrays for the identification of MDR Mycobacterium tuberculosis.

The emergence of Mycobacterium tuberculosis (Mtb), resistant to both isoniazid (INH) and rifampicin (RIF) (MDR-TB), is an increasing threat to tuberculosis control programs. Susceptibility testing of Mtb complex isolates by phenotypic methods requires a minimum of 14 days from a primary specimen. This can be reduced significantly if molecular analysis is used. Low density oligonucleotide arrays (macroarrays) have been used successfully for the detection of RIF resistance in Mtb. We describe the use of macroarray technology to identify Mtb complex isolates resistant to INH and/or RIF. The macroarray MDR-Mtb screen has been designed to detect mutations in the RIF resistance determining region (RRDR) of Mtb rpoB and loci in katG and mabA-inhA associated with INH resistance. A panel of Mtb isolates containing 38 different RRDR genotypes, 4 different genotypes within codon 315 of katG and 2 genotypes at mabA-inhA was used to validate the macroarray. The wild type (WT) genotype was correctly identified at all three loci. Of the 37 mutant rpoB genotypes, 36 were correctly detected; the single mutant not detected contained a 9 base insertion. All mutations within katG and mabA-inhA were correctly identified. We conclude that this low cost, rapid system can usefully detect the mutations associated with the vast majority of MDR-Mtb.

Antitubercular Agents↗
PubMed2005

Molecular analysis of isoniazid-resistant Mycobacterium tuberculosis isolates from England and Wales reveals the phylogenetic significance of the ahpC -46A polymorphism.

The present study investigated the prevalence and diagnostic potential of the most commonly reported mutations associated with isoniazid resistance, katG 315Thr, katG 315Asn, inhA -15T, inhA -8A, and the oxyR-ahpC intergenic region, in a population sample of 202 isoniazid-resistant Mycobacterium tuberculosis isolates and 176 randomly selected fully sensitive isolates from England and Wales identified by using a directed oligonucleotide array and limited DNA sequencing. The strains were recovered from patients originating from 29 countries; 41 isolates were multidrug resistant. Mutations affecting katG 315, the inhA promoter, and the oxyR-ahpC intergenic region were found in 62.7, 21.9, and 30% of 169 genotypically distinct isoniazid-resistant isolates, respectively, whereas they were found in 0, 0, and 8% of susceptible strains, respectively. The frequency of mutation at each locus was unrelated to the resistance profile or previous antituberculous drug therapy. The commonest mutation in the oxyR-ahpC intergenic region, ahpC -46A, was present in 23.7% of isoniazid-resistant isolates and 7.5% of susceptible isolates. This proved to be a phylogenetic marker for a subgroup of M. tuberculosis strains originating on the Indian subcontinent, which shared IS6110-based restriction fragment length polymorphism and spoligotype features with the Delhi strain and Central Asian strain CAS1; and this marker is strongly associated with isoniazid resistance and the katG 315Thr mutation. In total, 82.8% of unrelated isoniazid-resistant isolates could be identified by analysis of just two loci: katG 315 and the inhA promoter. Analysis of the oxyR-ahpC intergenic region, although phylogenetically interesting, does not contribute significantly to further identification of isoniazid-resistant isolates.

Antitubercular Agents↗
PubMed2005

Tuberculosis, HIV seroprevalence and intravenous drug abuse in prisoners.

High rates of tuberculosis (TB) and HIV are believed to exist in Russian prisons. Prisoners with TB were studied in order to identify the following: 1) prevalence of HIV, and risk factors for HIV and other blood-borne virus infections; and 2) clinical and social factors that might compromise TB treatment effectiveness and/or patient adherence and, hence, encourage treatment failure. A 1-yr cross-sectional prevalence study of 1,345 prisoners with TB was conducted at an in-patient TB facility in Samara, Russian Federation. HIV and hepatitis B and/or C co-infection occurred in 12.2% and 24.1% of prisoners, respectively, and rates were significantly higher than in civilians. Overall, 48.6% of prisoners used drugs, of which 88.3% were intravenous users. Prisoners were more likely to be intravenous drug users and HIV positive compared with civilians with TB, and 40.2% of prisoners shared needles. Two-thirds of prisoners (68.6%) had received previous TB drug therapy (frequently multiple, interrupted courses) and were significantly more likely than civilians to have had previous therapy consistent with the high drug-resistance rates seen. Prisons are major drivers of the tuberculosis and HIV epidemics. Novel strategies are needed to reduce the spread of blood borne diseases, particularly in intravenous drug users.

Adult↗
PubMed2005

[Molecular typing of the Mycobacterium tuberculosis strains circulating in central Russia: efficiency of spoligotyping and VNTR-MIRU].

Current problems of molecular epidemiology of the Mycobacterium tuberculosis strains circulating in Samara Region, Russia are discussed. A total of 190 isolates of Mycobacterium tuberculosis were typed using two PCR-based molecular methods. The cultures were isolated from civil and prison patients with pulmonary tuberculosis recruited from different tuberculosis institutions across the Samara region. The usefulness of spoligotyping and 15-locii VNTR-MIRU was assessed for genotyping of Mycobacterium in population with high prevalence of Beijing strains (67.9%) using statistical analyses that included calculation of Hunter-Gaston index. The VNTR-MIRU method was demonstrated to be more efficient and was characterized by higher discrimination (index 0.747) compare to spoligotyping (index 0.572). VNTR-MIRU loci 10, 26, 31, 39, 40 and ETR-A were mostly polymorphic and therefore recommended for use in screening. It could be performed by manual electrophoresid, provided that automated sequencing is not available.

Bacterial Typing Techniques↗
PubMed2004

Explaining risk factors for drug-resistant tuberculosis in England and Wales: contribution of primary and secondary drug resistance.

Drug-resistant tuberculosis can be transmitted (primary) or develop during the course of treatment (secondary). We investigated risk factors for each type of resistance. We compared all patients in England and Wales with isoniazid- and multidrug-resistant tuberculosis in two time-periods (1993-1994 and 1998-2000) with patients with fully sensitive tuberculosis, examining separately patients without and with previous tuberculosis (a proxy for primary and secondary drug-resistant tuberculosis). Patients with previous tuberculosis smear positivity and arrival in the United Kingdom <5 years were strongly associated with multidrug resistance and isoniazid resistance. In patients with no previous tuberculosis HIV infection, residence in London and foreign birth were risk factors for multidrug resistance, and non-white ethnicity, residence in London and HIV infection for isoniazid resistance. Risk factors for each type of resistance differ. Elevated risks associated with London residence, HIV positivity, and ethnicity were mainly seen in those without previous tuberculosis (presumed transmission).

Adolescent↗
PubMed2004

Outbreak of isoniazid resistant tuberculosis in north London.

BACKGROUND: A description is given of a major outbreak of isoniazid monoresistant tuberculosis (TB) chiefly in north London, including prisons. The earliest case was diagnosed in 1995 with most cases appearing after 1999. METHODS: Confirmation of a local cluster of cases was confirmed by restriction fragment length polymorphism (RFLP IS6110) typing or "rapid epidemiological typing" (RAPET). Further cases were found by retrospective analysis of existing databases, prospective screening of new isolates, and targeted epidemiological case detection including questionnaire analysis. RESULTS: By the end of 2001, 70 confirmed cases in London had been linked with a further 13 clinical cases in contacts and nine epidemiologically linked cases outside London. The epidemic curve suggests that the peak of the outbreak has not yet been reached. Cases in the outbreak largely belong to a social group of young adults of mixed ethnic backgrounds including several individuals from professional/business backgrounds. Compared with other cases of TB reported to the enhanced surveillance scheme in London during 1999-2001, the cases are more likely to be of white (26/70 (37%) v 1308/7666 (17%)) or black Caribbean ethnicity (17/70 (24%) v 312/7666 (4%)), born in the UK (41/70 (59%) v 1335/7666 (17%)), and male (52/70 (74%) v 4195/7666 (55%)). Drug misuse and/or prison detention are factors common to many cases. CONCLUSIONS: The investigation of the outbreak revealed significant problems on an individual patient and population based level including difficulties with contact tracing, compliance, and the risk of developing multidrug resistance. This incident has demonstrated the value of molecular strain typing in investigating an extensive outbreak of TB. This is the first documented outbreak involving a UK prison.

Adolescent↗
PubMed2004

The 'bear trap': the colliding epidemics of tuberculosis and HIV in Russia.

In April, 2003 the World Bank approved a long-awaited $150 million loan to the Russian Federation to support tuberculosis (TB) and AIDS control. Although the Russian Federation accounts for a relatively small fraction of the global TB case-load the proportion of cases which are drug-resistant and particularly multidrug-resistant is very high in some regions. HIV incidence, principally associated with intravenous drug abuse, has also increased dramatically and this will impact upon TB control efforts. Federation-wide data are limited but a focus on one region shows something of the confluence of the epidemics of HIV and TB. Approaching 200 cases of HIV-associated TB have occurred in the past two years, and the age structure of the HIV-infected population and that with high rates of TB shows sizeable overlap. The region has high rates of multidrug-resistant TB which are likely to impact considerably on efforts to meet this emerging and complex public health challenge. Insights gained through the examination of this one region can tell us something of the magnitude of the challenge now faced by both the international community and Russia.

Communicable Disease Control↗
PubMed2003

Modern laboratory diagnosis of tuberculosis.

One-third of the global population is believed to be infected with bacteria of the Mycobacterium tuberculosis complex, the causative agent of tuberculosis. More than 8 million new cases of tuberculosis occur annually leading to 2 million deaths. Mortality is particularly high in those coinfected with HIV and where the bacteria are multiple-drug-resistant strains--ie, strains resistant to at least isoniazid and rifampicin. Early diagnosis of tuberculosis and drug resistance improves survival and by identifying infectious cases promotes contact tracing, implementation of institutional cross-infection procedures, and other public-health actions. This review addresses significant advances made in the diagnosis of infection, clinical disease, and drug resistance over the past decade. It proposes operational criteria for a modern diagnostic service in the UK (as a model of a low-incidence country) and explores some of the economic issues surrounding the use of these techniques.

Antitubercular Agents↗
PubMed2003

Management of multiple drug-resistant tuberculosis.

There has been a worldwide increase in multiple drug-resistant tuberculosis (MDR-TB) which has in the past been associated with a poor prognosis. In the U.K., about half of the cases live in the London area and we have set out to obtain further information on their treatment and outcome. We examined the risk factors, drug resistance, drug treatment, sputum conversion, and outcome in patients with MDR-TB at three hospitals in South London and diagnosed during the period June 1995-January 1999. Human Immunodeficiency Virus (HIV)-positive patients were excluded. There were 760 patients resident in Lambeth, Southwark and Lewisham Health Authority (LSLHA) who were notified as tuberculosis (TB) during the time period and who were of negative or unknown HIV status. (The population of LSLHA is approx.750,000.) There was a total of 13 patients with MDR-TB, known or presumed to be HlV negative. Their median age was 28 years (range 15-53); nine (69%) were born outside the U.K. and 11 had pulmonary disease; they had organisms resistant to a median of two first-line drugs (range 2-4) and to a median of four of all drugs tested (range 2-10). They received treatment with a median of six drugs (range 3-9). Eight were followed up for at least 3 years (range 3-6) after the completion of treatment; at their last assessment none had features of active TB and all were sputum negative (smear and culture). Two returned to their countries of origin during treatment; they were sputum negative at that time. Two patients are well and continue on treatment in the U.K. One patient (known HIV negative) died following treatment failure. In conclusion, we obtained disease-free survival in eight cases of MDR-TB, known or presumed to be HIV negative and followed up for 3 years or more. The prognosis for patients treated at specialised centres is good (and better than is generally believed). We describe a new protocol for the detection and management of MDR-TB.

Adolescent↗
PubMed2003

Use of a phage-based assay for phenotypic detection of mycobacteria directly from sputum.

The phage amplified biologically assay is a new method for rapid and low-cost phenotypic determination of the drug sensitivities of Mycobacterium tuberculosis isolates and the detection of viable organisms in patient specimens. Infection of slowly growing mycobacteria with phage (phage D29) was followed by chemical virucide destruction of extracellular phage. Infected mycobacteria were mixed in culture with rapidly growing sensor cells, which the phage can also infect; i.e., lytic amplification of phage occurs. The aims of the present study were to optimize the speed and sensitivity of the assay and reduce its cost for developing countries by using an M. tuberculosis-spiked sputum model with (i). identification of inhibitory components of sputum and optimization of decontamination methods; (ii). simplification of the washing and development steps; (iii). reduction of the use of high-cost components, e.g., oleate-albumin-dextrose-catalase (OADC) supplement; and (iv). optimization of virucide treatment. The following results were obtained. (i). An inhibitory factor in sputum which could be removed by treatment of the sample with sodium dodecyl sulfate or NaOH decontamination was identified. (ii). A microcentrifuge-based approach with thixotropic silica as a bedding and resuspension agent was developed as an alternative to conventional centrifugation medium exchange. The yield was increased 228-fold, with increased speed and reduced cost. (iii). At present, after extracellular inactivation of phage, the ferrous ammonium sulfate (FAS) virucide is sequestered by dilution with an expensive supplement, OADC. Sodium citrate with calcium chloride was found to be a cost-effective after treatment with the FAS protectant and offered greater protection than OADC. Kinetic-lysis experiments indicated that an infection time of 1 to 3 h prior to FAS addition was optimal. (iv). Amplification of the signal (which corresponded to the burst size) was shown by allowing lysis prior to plating in a spiked medium model (up to 20-fold) and a spiked sputum model (up to 10-fold). A liquid culture detection method capable of detecting approximately 60 viable M. tuberculosis organisms in 1 ml of sputum was developed. Taken together, these improvements support the routine application of the assay to sputum specimens.

Bacteriophages↗
PubMed2003

Evaluation and utilization as a public health tool of a national molecular epidemiological tuberculosis outbreak database within the United Kingdom from 1997 to 2001.

The aim of this study was to develop a national model and analyze the value of a molecular epidemiological Mycobacterium tuberculosis DNA fingerprint-outbreak database. Incidents were investigated by the United Kingdom PHLS Mycobacterium Reference Unit (MRU) from June 1997 to December 2001, inclusive. A total of 124 incidents involving 972 tuberculosis cases, including 520 patient cultures from referred incidents and 452 patient cultures related to two population studies, were examined by using restriction fragment length polymorphism IS6110 fingerprinting and rapid epidemiological typing. Investigations were divided into the following three categories, reflecting different operational strategies: retrospective passive analysis, retrospective active analysis, and retrospective prospective analysis. The majority of incidents were in the retrospective passive analysis category, i.e., the individual submitting isolates has a suspicion they may be linked. Outbreaks were examined in schools, hospitals, farms, prisons, and public houses, and laboratory cross-contamination events and unusual clinical presentations were investigated. Retrospective active analysis involved a major outbreak centered on a high school. Contact tracing of a teenager with smear-positive pulmonary tuberculosis matched 14 individuals, including members of his class, and another 60 cases were identified in schools clinically and radiologically and by skin testing. Retrospective prospective analysis involved an outbreak of 94 isoniazid-resistant tuberculosis cases in London, United Kingdom, that began after cases were identified at one hospital in January 2000. Contact tracing and comparison with MRU databases indicated that the earliest matched case had occurred in 1995. Subsequently, the MRU changed to an active prospective analysis targeting linked isoniazid-monoresistant isolates for follow up. The patients were multiethnic, born mainly in the United Kingdom, and included professionals, individuals from the music industry, intravenous drug abusers, and prisoners.

Antitubercular Agents↗
PubMed2002

The diagnosis and management of multiple-drug-resistant-tuberculosis at the beginning of the new millenium.

Multiple-drug-resistant tuberculosis (MDRTB) is more difficult to treat and the treatment is less likely to produce favourable results compared to treatment of drug-sensitive disease. Success requires close co-operation between the laboratory, which defines a case as MDRTB, and the clinical team, who will treat it as well as the public health staff who will address aspects of contact tracing and institutional cross-infection. National surveys have indicated that MDRTB occurs at a higher rate in some countries such as Estonia and Latvia (14.1% and 9% respectively, in 1998) and Russia (although there are only limited validated data). In contrast, in Western Europe and in some countries of Eastern Europe, such as the Czech Republic, Slovenia, Slovakia and Poland with good tuberculosis (TB) prevention and treatment programmes, the combined MDRTB prevalence was 1% or less. The early diagnosis of MDRTB and case management by experienced teams from the outset remains the best hope clinically for these patients. Adequately supervised and prolonged combination chemotherapy is essential, with drug choice governed mainly by quality-controlled in vitro drug susceptibility data. There is a more limited role for surgery, and immunomodulating therapy, such as the use of gamma-interferon, may have a useful adjunct role. Clearly the most important therapeutic modality for MDRTB is to treat drug-sensitive TB correctly in the first instance and prevent the emergence of resistant TB.

Antitubercular Agents↗
PubMed2002

Molecular epidemiology of tuberculosis in London 1995-7 showing low rate of active transmission.

BACKGROUND: Tuberculosis notification rates for London have risen dramatically in recent years. Molecular typing of Mycobacterium tuberculosis has contributed to our understanding of the epidemiology of tuberculosis throughout the world. This study aimed to assess the degree of recent transmission of M tuberculosis in London and subpopulations of the community with high rates of recent transmission. METHODS: M tuberculosis isolates from all persons from Greater London diagnosed with culture positive tuberculosis between 1 July 1995 and 31 December 1997 were genetically fingerprinted using IS6110 restriction fragment length polymorphism (RFLP) typing. A structured proforma was used during record review of cases of culture confirmed tuberculosis. Cluster analysis was performed and risk factors for clustering were examined in a univariate analysis followed by a logistic regression analysis with membership of a cluster as the outcome variable. RESULTS: RFLP patterns were obtained for 2042 isolates with more than four copies of IS6110; 463 (22.7%) belonged to 169 molecular clusters, which ranged in size from two (65% of clusters) to 12 persons. The estimated rate of recent transmission was 14.4%. Young age (0-19 years) (odds ratio (OR) 2.65, 95% confidence interval (CI) 1.59 to 4.44), birth in the UK (OR 1.55, 95% CI 1.04 to 2.03), black Caribbean ethnic group (OR 2.19, 95% CI 1.15 to 4.16), alcohol dependence (OR 2.33, 95% CI 1.46 to 3.72), and streptomycin resistance (OR 1.82, 95% CI 1.15 to 2.88) were independently associated with an increased risk of clustering. CONCLUSIONS: Tuberculosis in London is largely caused by reactivation or importation of infection by recent immigrants. Newly acquired infection is also common among people with recognised risk factors. Preventative interventions and early diagnosis of immigrants from areas with a high incidence of tuberculosis, together with thorough contact tracing and monitoring of treatment outcome among all cases of tuberculosis (especially in groups at higher risk of recent infection), remains most important.

Adolescent↗
PubMed2001

Molecular techniques in the diagnosis of Mycobacterium tuberculosis and the detection of drug resistance.

Early diagnosis of Mycobacterium tuberculosis disease is crucial in initiating treatment and interrupting the train of transmission. The increasing incidence of MDR TB worldwide has also placed emphasis on the need for early detection of drug resistance, particularly to isoniazid and rifampicin. Molecular diagnostic techniques and automated culture systems have reduced turnaround times in the modern mycobacteriology laboratory, and the continuing evaluation and development of such techniques is increasing the use of molecular technology in developed nations. Simple phenotypic methods for the detection of resistance to first-line drugs and genotypic kit-form assays for detection of rifampicin resistance have been developed that have become key tools in the containment of MDR TB.

Humans↗
PubMed2000

A clinical, microbiological and economic analysis of a national service for the rapid molecular diagnosis of tuberculosis and rifampicin resistance in Mycobacterium tuberculosis.

A clinical, microbiological and economic study of a national rapid molecular service for the identification of Mycobacterium tuberculosis and the determination of rifampicin resistance in smear-positive sputum samples (and other primary specimens) was performed. Ninety-one primary specimens, of which 55 were smear-positive sputum, were examined by molecular and conventional assays. Concordance of molecular results from smear-positive sputum specimens with tuberculosis diagnosis and rifampicin resistance by conventional analysis was 52 (94.5%) of 55 and 44 (91.7%) of 48, respectively. Concordance of molecular analysis on all primary specimens was 81 (89.0%) of 91 (diagnosis) and 55 (90.2%) of 61 (rifampicin resistance). Approximately 28 days were saved in the time to diagnosis by using the molecular assay. Hospitals can reduce the cost of inappropriate isolation of patients with risk factors for multiple drug-resistant tuberculosis (MDRTB) who subsequently are shown to have drug-sensitive tuberculosis. At one hospital potential annual savings were between pound sterling 50000 and pound sterling 150000. Of the nine MDRTB cases identified, all had a previous diagnosis of tuberculosis, 78% were born overseas, 44% were known to be non-compliant with therapy, but only one case (12.5%) was HIV positive. HIV status was not significantly different between MDRTB and drug-sensitive tuberculosis cases. Over 75% of specimens were taken while the patient was on therapy. Isolates from >50% of the MDRTB cases were resistant to three or more drugs and one was resistant to seven drugs. All patients were placed on additional therapy once the molecular result was known; this was subsequently modified based on the results of in-vitro drug susceptibility testing. All survived at least 6 months of follow-up. There was no difference in the proportion of successful cultures from smear-positive samples from patients with drug-sensitive tuberculosis or MDRTB who were on therapy. Molecular rifampicin resistance assays are reliable for diagnosis in cases with smear-positive disease.

Adult↗
PubMed2000

Differentiation of Mycobacterium tuberculosis complex and nontuberculous mycobacterial liquid cultures by using peptide nucleic acid-fluorescence In situ hybridization probes.

A blinded comparison of peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) with routine identification methods was performed on 74 consecutively positive mycobacterial liquid cultures. All Mycobacterium tuberculosis cultures (48 of 48) and 22 of 27 (81. 5%) nontuberculous cultures were correctly identified (including one mixed culture). Five isolates yielded no reaction with either probe and were identified as Mycobacterium xenopi, Mycobacterium fortuitum, or Mycobacterium flavescens.

Bacteriological Techniques↗