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Breen RAM, Barry SM, Smith CJ, Shorten RJ, Dilworth JP, Cropley I, McHugh TD, Gillespie SH, Janossy G, Lipman MCI. Clinical application of a rapid lung-orientated immunoassay in individuals with possible tuberculosis. Thorax 2008; 63:67-71. [PMID: 17675319 DOI: 10.1136/thx.2007.078857] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Immunological ex vivo assays to diagnose tuberculosis (TB) have great potential but have largely been blood-based and poorly evaluated in active TB. Lung sampling enables combined microbiological and immunological testing and uses higher frequency antigen-specific responses than in blood. METHODS A prospective evaluation was undertaken of a flow cytometric assay measuring the percentage of interferon-gamma synthetic CD4+ lymphocytes following stimulation with purified protein derivative of Mycobacterium tuberculosis (PPD) in bronchoalveolar lavage fluid from 250 sputum smear-negative individuals with possible TB. A positive assay was defined as >1.5%. RESULTS Of those who underwent lavage and were diagnosed with active TB, 95% (106/111) had a positive immunoassay (95% CI 89% to 98%). In 139 individuals deemed not to have active TB, 105 (76%) were immunoassay negative (95% CI 68% to 82%). Of the remaining 24% (34 cases) with a positive immunoassay, a substantial proportion had evidence of untreated TB; in two of these active TB was subsequently diagnosed. Assay performance was unaffected by HIV status, disease site or BCG vaccination. In culture-positive pulmonary cases, response to PPD was more sensitive than nucleic acid amplification testing (94% vs 73%). The use of early secretory antigen target-6 (ESAT-6) responses in 71 subjects was no better than PPD, and 19% of those with culture-confirmed TB and a positive PPD immunoassay had no detectable response to ESAT-6. CONCLUSIONS These findings suggest that lung-orientated immunological investigation is a potentially powerful tool in diagnosing individuals with sputum smear-negative active TB, regardless of HIV serostatus.
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O'Sullivan DM, Sander C, Shorten RJ, Gillespie SH, Hill AVS, McHugh TD, McShane H, Tchilian EZ. Evaluation of liquid culture for quantitation of Mycobacterium tuberculosis in murine models. Vaccine 2007; 25:8203-5. [PMID: 17980937 DOI: 10.1016/j.vaccine.2007.09.065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 09/12/2007] [Indexed: 11/18/2022]
Abstract
Quantitation of bacterial load in tissues is essential for experimental investigation of Mycobacterium tuberculosis infection and immunity. We have used an automated liquid culture system to determine the number of colony forming units (CFU) in murine tissues and compared the results to those obtained by conventional plating on Middlebrook agar. There is an overall good correlation between results obtained by the two methods. Although less consistency and more contamination was observed in the automated liquid culture, the method is more sensitive, less labour intensive and allows the processing of large numbers of samples.
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Williams KJ, Ling CL, Jenkins C, Gillespie SH, McHugh TD. A paradigm for the molecular identification of Mycobacterium species in a routine diagnostic laboratory. J Med Microbiol 2007; 56:598-602. [PMID: 17446280 DOI: 10.1099/jmm.0.46855-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to improve the identification ofMycobacteriumspecies in the context of a UK teaching hospital. Real-time PCR assays were established to enable the rapid differentiation betweenMycobacterium tuberculosis(MTB) complex andMycobacteriumspecies other thantuberculosis(MOTT), followed by 16S rRNA gene sequencing for the speciation of MOTT. Real-time PCR assays gave comparable results to those from the reference laboratory. The implementation of these PCR assays using an improved bead extraction method has enhanced the mycobacterial diagnostic service at the Royal Free Hospital by providing a rapid means of differentiating between MTB complex and MOTT, and would be simple to implement in similar laboratories. Sequence analysis successfully identified a range ofMycobacteriumspp. representative of those encountered in the clinical setting of the authors, includingMycobacterium aviumcomplex,Mycobacterium fortuitumgroup,Mycobacterium chelonae–Mycobacterium abscessusgroup,Mycobacterium xenopiandMycobacterium gordonae. It provides a useful tool for the identification of MOTT when clinically indicated.
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Uriyo J, Gosling RD, Maddox V, Sam NE, Schimana W, Gillespie SH, McHugh TD. Prevalences of Pneumocystis jiroveci, Mycobacterium tuberculosis and Streptococcus pneumoniae infection in children with severe pneumonia, in a tertiary referral hospital in northern Tanzania. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2006; 100:245-9. [PMID: 16630382 DOI: 10.1179/136485913x13789813917580] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
At the Kilimanjaro Christian Medical Centre, a tertiary referral hospital in northern Tanzania, both the number of paediatric cases of lower respiratory-tract infection (LRTI) and the associated mortality increased between 2000 and 2001. Molecular diagnostic tools were used to enhance the identification of the pathogens responsible for this perceived increase. All 72 children aged between 2 and 60 months who were admitted with LRTI over a 3-month period were enrolled in the study. Induced sputum was collected from each child and, if the parents consented, the subjects were also tested for HIV. The sputum samples were each checked for bacteria by culture and, in amplification assays, for the DNA of Pneumocystis jiroveci, Mycobacterium tuberculosis and Streptococcus pneumoniae. Twenty-two (50%) of the 44 children tested for HIV had HIV-1 antibodies. Although only two children, both aged <6 months, were found PCR-positive for P. jiroveci, and only one was found positive for M. tuberculosis, 46 (including one of those found positive for P. jiroveci and the child found positive for M. tuberculosis) were found PCR-positive for S. pneumoniae. It therefore appears that most paediatric cases of LRTI who present at the hospital are attributable to S. pneumoniae, and that infections with this pathogen are entirely responsible for the observed increase in the incidence of LTRI in the local children. The increase seen in LRTI-associated mortality among the children may be the result of pneumococcal antibiotic resistance.
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Creer DD, Dilworth JP, Gillespie SH, Johnston AR, Johnston SL, Ling C, Patel S, Sanderson G, Wallace PG, McHugh TD. Aetiological role of viral and bacterial infections in acute adult lower respiratory tract infection (LRTI) in primary care. Thorax 2005; 61:75-9. [PMID: 16227331 PMCID: PMC2080713 DOI: 10.1136/thx.2004.027441] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Lower respiratory tract infections (LRTI) are a common reason for consulting general practitioners (GPs). In most cases the aetiology is unknown, yet most result in an antibiotic prescription. The aetiology of LRTI was investigated in a prospective controlled study. METHODS Eighty adults presenting to GPs with acute LRTI were recruited together with 49 controls over 12 months. Throat swabs, nasal aspirates (patients and controls), and sputum (patients) were obtained and polymerase chain reaction (PCR) and reverse transcriptase polymerase chain reaction (RT-PCR) assays were used to detect Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumophila, influenza viruses (AH1, AH3 and B), parainfluenza viruses 1-3, coronaviruses, respiratory syncytial virus, adenoviruses, rhinoviruses, and enteroviruses. Standard sputum bacteriology was also performed. Outcome was recorded at a follow up visit. RESULTS Potential pathogens were identified in 55 patients with LRTI (69%) and seven controls (14%; p<0.0001). The identification rate was 63% (viruses) and 26% (bacteria) for patients and 12% (p<0.0001) and 6% (p = 0.013), respectively, for controls. The most common organisms identified in the patients were rhinoviruses (33%), influenza viruses (24%), and Streptococcus pneumoniae (19%) compared with 2% (p<0.001), 6% (p = 0.013), and 4% (p = 0.034), respectively, in controls. Multiple pathogens were identified in 18 of the 80 LRTI patients (22.5%) and in two of the 49 controls (4%; p = 0.011). Atypical organisms were rarely identified. Cases with bacterial aetiology were clinically indistinguishable from those with viral aetiology. CONCLUSION Patients presenting to GPs with acute adult LRTI predominantly have a viral illness which is most commonly caused by rhinoviruses and influenza viruses.
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Perrin FMR, Breen RAM, Lipman MCI, Shorten RJ, Gillespie SH, McHugh TD. Is there a relationship between Mycobacterium tuberculosis strain type and TB paradoxical reaction? Thorax 2005; 60:706-7. [PMID: 16061718 PMCID: PMC1747474 DOI: 10.1136/thx.2005.044321] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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McHugh TD, Batt SL, Shorten RJ, Gosling RD, Uiso L, Gillespie SH. Mycobacterium tuberculosis lineage: a naming of the parts. Tuberculosis (Edinb) 2005; 85:127-36. [PMID: 15850751 DOI: 10.1016/j.tube.2004.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 06/03/2004] [Accepted: 06/09/2004] [Indexed: 11/18/2022]
Abstract
There have been many reports of groups of related Mycobacterium tuberculosis strains described variously as lineages, families or clades. There is no objective definition of these groupings, making it impossible to define relationships between those groups with biological advantages. Here we describe two groups of related strains obtained from an epidemiological study in Tanzania, which we define as the Kilimanjaro and Meru lineages on the basis of IS6110 restriction fragment length polymorphism (RFLP), polymorphic GC rich sequence (PGRS) RFLP and mycobacterial interspersed repeat unit (MIRU) typing. We investigated the concordance between each of the typing techniques and the dispersal of the typing profiles from a core pattern. The Meru lineage is more dispersed than the Kilimanjaro lineage and we speculate that the Meru lineage is older. We suggest that this approach provides an objective definition that proves robust in this epidemiological study. Such a framework will permit associations between a lineage and clinical or bacterial phenomenon to be tested objectively. This definition will also enable new putative lineages to be objectively tested.
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Shorten RJ, Gillespie SH, Sule O, Lipman M, McHugh TD. Molecular strain typing of M. tuberculosis isolates from a suspected outbreak involving a faulty bronchoscope. J Hosp Infect 2005; 61:86-7. [PMID: 16054947 DOI: 10.1016/j.jhin.2004.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Accepted: 12/20/2004] [Indexed: 11/28/2022]
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Conaty SJ, Claxton AP, Enoch DA, Hayward AC, Lipman MCI, Gillespie SH. The interpretation of nucleic acid amplification tests for tuberculosis: do rapid tests change treatment decisions? J Infect 2005; 50:187-92. [PMID: 15780411 DOI: 10.1016/j.jinf.2004.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVES To describe changes in treatment decisions after receipt of nucleic acid amplification (NAA) test for the diagnosis of M. tuberculosis. METHODS Retrospective notes review of treatment decisions in patients receiving a NAA test for suspected pulmonary or non-pulmonary tuberculosis at the Royal Free Hospital in London between March 2001 and February 2002. Notes were sought on a 50% random sample of patients with both smear and NAA negative specimens and all patients with other specimen results. RESULTS Two hundred and fifty patients were tested with NAA; clinical details were obtained on 138; 61 were ever treated. Seventeen (17/18) smear-negative patients were started on treatment after a positive NAA; none of six smear-negative patients treated prior to a negative NAA result had treatment stopped. Seventeen (17/21) smear-positive patients were treated prior to NAA result and all were NAA positive; treatment was delayed in four smear-positive patients until receipt of an NAA and one NAA-negative patient was not treated. CONCLUSIONS In routine practice a positive test in an untreated smear-negative patient leads to decision to treat in almost all, but the proportion testing positive is low (8% or 17/219). In patients already on treatment negative tests did not lead to decisions to stop.
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Appelbaum PC, Gillespie SH, Burley CJ, Tillotson GS. Antimicrobial selection for community-acquired lower respiratory tract infections in the 21st century: a review of gemifloxacin. Int J Antimicrob Agents 2005; 23:533-46. [PMID: 15194123 DOI: 10.1016/j.ijantimicag.2004.02.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Community-acquired lower respiratory tract infections (LRTIs) are more prevalent in the elderly than in children and younger adults and form a significant proportion of all consultations and hospital admissions in this older age group. Furthermore, in a world of increasing life expectancy the trend seems unlikely to be reversed. Antimicrobial treatment of community-acquired pneumonia (CAP) must cover Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis, and in many circumstances should also cover the intracellular (atypical) pathogens. In contrast, acute exacerbations of chronic bronchitis (AECB) are mainly associated with H. influenzae and S. pneumoniae and not with atypical bacteria: in severe cases, other Gram-negative bacteria may be involved. Frequently in LRTIs, the aetiology of the infection cannot be identified from the laboratory specimens and treatment has to be empirical. In such situations it is important to not only to use an antibiotic that covers all likely organisms, but also one that has good activity against these organisms given the local resistance patterns. Gemifloxacin is a new quinolone antibiotic that targets pneumococcal DNA gyrase and topoisomerase IV and is highly active against S. pneumoniae including penicillin-, macrolide- and many ciprofloxacin-resistant strains, as well as H. influenzae and the atypical pathogens. In clinical trials in CAP and AECB, gemifloxacin has been shown to be as effective a range of comparators and demonstrated an adverse event profile that was in line with the comparator agents. In one long-term study in AECB significantly more patients receiving gemifloxacin than clarithromycin remained free of recurrence after 26 weeks. The improved potency, broad spectrum of activity and proven clinical and bacteriological efficacy and safety profile should make it a useful agent in the 21st century battle against community-acquired LRTIs.
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McHugh TD, Pope CF, Ling CL, Patel S, Billington OJ, Gosling RD, Lipman MC, Gillespie SH. Prospective evaluation of BDProbeTec strand displacement amplification (SDA) system for diagnosis of tuberculosis in non-respiratory and respiratory samples. J Med Microbiol 2004; 53:1215-1219. [PMID: 15585500 DOI: 10.1099/jmm.0.45780-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Nucleic acid amplification techniques (NAATs) have been demonstrated to make significant improvements in the diagnosis of tuberculosis (TB), particularly in the time to diagnosis and the diagnosis of smear-negative TB. The BD ProbeTec strand displacement amplification (SDA) system for the diagnosis of pulmonary and non-pulmonary tuberculosis was evaluated. A total of 689 samples were analysed from patients with clinically suspected TB. Compared with culture, the sensitivity and specificity for pulmonary samples were 98 and 89 %, and against final clinical diagnosis 93 and 92 %, respectively. This assay has undergone limited evaluation for non-respiratory samples and so 331 non-respiratory samples were tested, identifying those specimens that were likely to yield a useful result. These were CSF (n = 104), fine needle aspirates (n = 64) and pus (n = 41). Pleural fluid (n = 47) was identified as a poor specimen. A concern in using the SDA assay was that low-positive samples were difficult to interpret; 7.8 % of specimens fell into this category. Indeed, 64 % of the discrepant results, when compared to final clinical diagnosis, could be assigned as low-positive samples. Specimen type did not predict likelihood of a sample being in the low-positive zone. Although the manufacturers do not describe the concept of a low-positive zone, we have found that it aids clinical diagnosis.
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Chintu C, Bhat GJ, Walker AS, Mulenga V, Sinyinza F, Lishimpi K, Farrelly L, Kaganson N, Zumla A, Gillespie SH, Nunn AJ, Gibb DM. Co-trimoxazole as prophylaxis against opportunistic infections in HIV-infected Zambian children (CHAP): a double-blind randomised placebo-controlled trial. Lancet 2004; 364:1865-71. [PMID: 15555666 DOI: 10.1016/s0140-6736(04)17442-4] [Citation(s) in RCA: 249] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND No trials of co-trimoxazole (trimethoprim-sulfamethoxazole) prophylaxis for HIV-infected adults or children have been done in areas with high levels of bacterial resistance to this antibiotic. We aimed to assess the efficacy of daily co-trimoxazole in such an area. METHODS We did a double-blind randomised placebo-controlled trial in children aged 1-14 years with clinical features of HIV infection in Zambia. Primary outcomes were mortality and adverse events possibly related to treatment. Analysis was by intention to treat. FINDINGS In October, 2003, the data and safety monitoring committee recommended early stopping of the trial. 541 children had been randomly assigned; seven were subsequently identified as HIV negative and excluded. After median follow-up of 19 months, 74 (28%) children in the co-trimoxazole group and 112 (42%) in the placebo group had died (hazard ratio [HR] 0.57 [95% CI 0.43-0.77], p=0.0002). This benefit applied in children followed up beyond 12 months (n=320, HR 0.48 [0.27-0.84], test for heterogeneity p=0.60) and across all ages (test for heterogeneity p=0.82) and baseline CD4 counts (test for heterogeneity p=0.36). 16 (6%) children in the co-trimoxazole group had grade 3 or 4 adverse events compared with 18 (7%) in the placebo group. These events included rash (one placebo), and a neutrophil count on one occasion less than 0.5x10(9)/L (16 [6%] co-trimoxazole vs seven [3%] placebo, p=0.06). Pneumocystis carinii was identified by immunofluorescence in only one (placebo) of 73 nasopharyngeal aspirates from children with pneumonia. INTERPRETATION Our results suggest that children of all ages with clinical features of HIV infection should receive co-trimoxazole prophylaxis in resource-poor settings, irrespective of local resistance to this drug.
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Kerbiriou L, Ustianowski A, Johnson M, Gillespie SH, Miller RF, Lipman M. Reply. Clin Infect Dis 2004. [DOI: 10.1086/392519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Charalambous BM, Batt SL, Peek AC, Mwerinde H, Sam N, Gillespie SH. Quantitative validation of media for transportation and storage of Streptococcus pneumoniae. J Clin Microbiol 2004; 41:5551-6. [PMID: 14662939 PMCID: PMC309041 DOI: 10.1128/jcm.41.12.5551-5556.2003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The need to design effective Streptococcus pneumoniae vaccines and to monitor resistance means that it is essential to have efficient methods to determine carriage rates. Two liquid media, consisting of skim milk, glycerol, glucose, and tryptone soya broth (STGG) or skim milk, glycerol, and glucose (SGG) alone, were evaluated for their ability to maintain pneumococcal viability. Optimal recovery of S. pneumoniae was achieved when swabs were transferred to STGG medium prior to plating onto blood agar-gentamicin selective plates (22%) compared to 7% when plated out directly (P < 0.0001 by Fisher's exact test). Both STGG and SGG media are appropriate for the long-term storage of pneumococci and primary swab samples at -70 degrees C, with no decrease in viable count observed following repeated freeze-thaw cycles. Samples could be stored refrigerated for up to 3 days in either STGG or SGG medium with no significant loss of viability. Viability decreased progressively in storage at 20 to 30 degrees C, with greater losses of viability occurring at the higher temperatures. There were no significant differences in viability between isolates in the two media. STGG preserved pneumococci significantly better (about twofold) than SGG medium at 21 degrees C (P < 0.0001) and 30 degrees C (P < 0.0001). Samples can be stored for 4 and 2.5 days at 6 to 8 degrees C, 28 and 17 h at 21 degrees C, and 15 and 7 h at 30 degrees C in STGG and SGG media, respectively. For field studies undertaken in resource-limited environments, SGG medium can be prepared by using locally available materials. The quantitative data reported in this study will enable researchers to plan appropriate transport and storage protocols.
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Kerbiriou L, Ustianowski A, Johnson MA, Gillespie SH, Miller RF, Lipman MCI. Human immunodeficiency virus type 1-related pulmonary Mycobacterium xenopi infection: a need to treat? Clin Infect Dis 2003; 37:1250-4. [PMID: 14557971 DOI: 10.1086/378806] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2003] [Accepted: 06/30/2003] [Indexed: 11/03/2022] Open
Abstract
We report treatment decisions and outcomes for 20 patients who were infected with human immunodeficiency virus type 1 (HIV-1) and were receiving highly active antiretroviral therapy (HAART) who had respiratory symptoms and from whom Mycobacterium xenopi was isolated. All patients also had coexisting pulmonary pathologic conditions. The median blood T cell CD4 count was 37 cells/microL (range, 2-480 cells/microL). Fifteen of 20 patients received no antimycobacterial therapy and remain healthy after a median of approximately 4 years of follow-up, and 2 patients required treatment specifically for M. xenopi infection, both showing clinical improvement. We conclude that pulmonary M. xenopi isolation in HIV-1 patients receiving HAART does not usually require specific treatment.
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Kanduma E, McHugh TD, Gillespie SH. Molecular methods for Mycobacterium tuberculosis strain typing: a users guide. J Appl Microbiol 2003; 94:781-91. [PMID: 12694442 DOI: 10.1046/j.1365-2672.2003.01918.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
There are now a wide range of techniques available to type Mycobacterium tuberculosis, the problem is to choose the correct technique. For large scale epidemiological studies the portability and standardization of IS6110 restriction fragment length polymorphism (RFLP) means that this remains the gold standard technique. In the next few years the internationally standard mycobacterial interspersed repetitive unit (MIRU) may come to challenge this primacy. Low copy number stains remain a problem and these can be typed by either polymorphic Guanine cytosine-rich repetitive sequence (PGRS) or MIRU-variable numbers of tandem repeat (VNTR). To confirm whether strains are part of a true cluster PGRS remains the method of choice. For local outbreaks and investigations of laboratory cross contamination where speed is of greatest importance suspect strains should be initially investigated using a PCR-based method. The superior reproducibility and discrimination of MIRU-VNTR means that these methods should be favoured. If matches are found, then further confirmation of identity can be achieved using IS6110 RFLP or PGRS if the strains prove to have a low IS6110 copy number.
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Gillespie SH, Charalambous BM. A novel method for evaluating the antimicrobial activity of tuberculosis treatment regimens. Int J Tuberc Lung Dis 2003; 7:684-9. [PMID: 12870691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
OBJECTIVE To evaluate the clinical response to antituberculosis chemotherapy rapidly. METHOD Sputum viable counts from a previously published clinical trial comparing a standard regimen and one containing isoniazid, rifampicin and ciprofloxacin were re-evaluated using an exponential decay model. The results were fitted to a one or two phase exponential decline. The decline in viable counts followed a curve described by a single-phase exponential decay model. From these data the time taken to reduce the viable count by 50% (vt50) was calculated to estimate the bactericidal effect of the regimens. RESULTS AND CONCLUSION This method shows promise as a means for early identification of patients who are responding poorly as a result of resistance or poor immune response and for comparing anti-tuberculosis regimens in clinical trials. The failure to show a two-phase exponential decay curve suggested that either the sputum does not contain bacteria upon which only drugs with a sterilising activity act or that they are not present in sufficient numbers to have a significant impact on the total viable count. Further studies are required to understand the physiological state of organisms being sampled in sputum.
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Ruddy M, McHugh TD, Dale JW, Banerjee D, Maguire H, Wilson P, Drobniewski F, Butcher P, Gillespie SH. Estimation of the rate of unrecognized cross-contamination with mycobacterium tuberculosis in London microbiology laboratories. J Clin Microbiol 2002; 40:4100-4. [PMID: 12409381 PMCID: PMC139701 DOI: 10.1128/jcm.40.11.4100-4104.2002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Isolates from patients with confirmed tuberculosis from London were collected over 2.5 years between 1995 and 1997. Restriction fragment length polymorphism (RFLP) analysis was performed by the international standard technique as part of a multicenter epidemiological study. A total of 2,779 samples representing 2,500 individual patients from 56 laboratories were examined. Analysis of these samples revealed a laboratory cross-contamination rate of between 0.54%, when only presumed cases of cross-contamination were considered, and 0.93%, when presumed and possible cases were counted. Previous studies suggest an extremely wide range of laboratory cross-contamination rates of between 0.1 and 65%. These data indicate that laboratory cross-contamination has not been a common problem in routine practice in the London area, but in several incidents patients did receive full courses of therapy that were probably unnecessary.
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Whiting GC, Evans JT, Patel S, Gillespie SH. Purification of native alpha-enolase from Streptococcus pneumoniae that binds plasminogen and is immunogenic. J Med Microbiol 2002; 51:837-843. [PMID: 12435062 DOI: 10.1099/0022-1317-51-10-837] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many pathogenic bacteria express plasminogen receptors on their surface, which may play a role in the dissemination of organisms by binding plasminogen that, when converted to plasmin, can digest extracellular matrix proteins. A 45-kDa protein was purified from Streptococcus pneumoniae and confirmed as an alpha-enolase by its ability to catalyse the dehydration of 2-phospho-D-glycerate to phosphoenolpyruvate and by N-terminal sequencing. The activity of alpha-enolase was found in the cytoplasm and in whole cells. Activity was also demonstrated in cell wall fractions, which confirmed that alpha-enolase is a cytoplasmic antigen also expressed on the surface of S. pneumoniae. The plasminogen-binding activity of alpha-enolase was examined by Western blot, which showed that purified alpha-enolase was able to bind human plasminogen. Immunoblots of the purified 45-kDa alpha-enolase with 22 sera from patients with pneumococcal disease showed binding in 15 cases, indicating that pneumococcal enolase is immunogenic.
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Maguire H, Dale JW, McHugh TD, Butcher PD, Gillespie SH, Costetsos A, Al-Ghusein H, Holland R, Dickens A, Marston L, Wilson P, Pitman R, Strachan D, Drobniewski FA, Banerjee DK. Molecular epidemiology of tuberculosis in London 1995-7 showing low rate of active transmission. Thorax 2002; 57:617-22. [PMID: 12096206 PMCID: PMC1746370 DOI: 10.1136/thorax.57.7.617] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
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.
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Gillespie SH. Mycobacterium tuberculosis Protocols. Methods in Molecular Medicine series.: T. Parish and N. G. Stoker, Eds. Humana Press, Totowa, NJ, USA. ISBN 0-89603-776-2. 403 pp. J Antimicrob Chemother 2002. [DOI: 10.1093/jac/49.1.226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Barlow RE, Gascoyne-Binzi DM, Gillespie SH, Dickens A, Qamer S, Hawkey PM. Comparison of variable number tandem repeat and IS6110-restriction fragment length polymorphism analyses for discrimination of high- and low-copy-number IS6110 Mycobacterium tuberculosis isolates. J Clin Microbiol 2001; 39:2453-7. [PMID: 11427553 PMCID: PMC88169 DOI: 10.1128/jcm.39.7.2453-2457.2001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The present study was designed to evaluate the use of variable number tandem repeat (VNTR) and IS6110-restriction fragment length polymorphism (RFLP) analyses in combination as a two-step strategy for discrimination (as measured by the Hunter-Gaston Discrimination Index [HGDI]) of both high- and low-copy-number IS6110 Mycobacterium tuberculosis isolates compared to IS6110-RFLP alone with an unselected collection of isolates. Individually, IS6110-RFLP fingerprinting produced six clusters that accounted for 69% of the low-copy-number IS6110 isolates (five clusters) and 5% of the high-copy-number IS6110 isolates (one cluster). A total of 39% of all the isolates were clustered (HGDI = 0.97). VNTR analysis generated a total of 35 different VNTR allele profile sets from 93 isolates (HGDI = 0.938). Combining IS6110-RFLP analysis with VNTR analysis reduced the overall percentage of clustered isolates to 29% (HGDI = 0.988) and discriminated a further 27% of low-copy-number isolates that would have been clustered by IS6110-RFLP alone. The use of VNTR analysis as an initial typing strategy facilitates further analysis by IS6110-RFLP, and more importantly, VNTR analysis subdivides some IS6110-RFLP-defined clusters containing low- and single-copy IS6110 isolates.
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Abstract
Antibiotic resistance poses a serious threat to modern medical practice making treatment more difficult and is associated with increased mortality among patients infected with resistant organisms. There is clear evidence that acquisition of resistance is associated with a decrease in the fitness of the organisms at least in the short term. Evidence from in vitro experiments indicates that bacteria have the ability to adapt to this deficit and recover fitness on serial passage. More recent results show that identical organisms isolated from patients in outbreaks have an initial deficit but that adaptation occurs in vivo. Strategies directed towards controlling resistance must move beyond wishful thinking that supposes that these organisms will disappear merely with control of prescribing. In some cases, resistance will not disappear because there is no evolutionary disadvantage in being resistant once adaptation has taken place. It is important, therefore, that we direct our efforts towards preventing primary resistance emerging and in limiting the spread of resistant strains. Ultimately, we must look again to new drug discovery to improve our therapeutic armoury.
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Gillespie SH. In Vitro Assessment of the Fitness of Resistant M. tuberculosis Bacteria by Competition Assay. METHODS IN MOLECULAR MEDICINE 2001; 48:233-236. [PMID: 21374423 DOI: 10.1385/1-59259-077-2:233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Bacteria become resistant by a number of different mechanisms, and these include mutation in chromosomal genes (1), acquisition of plasmids (2), insertion of bacteriophage, transposon or insertion sequence DNA (3-5), or gene mosaicism (6). There is a dogma that bacteria that become resistant pay a significant physiological price and that if antimicrobial prescribing is controlled it will result in the eradication of resistant organisms. There are only very few studies that investigate the physiology of resistance acquisition and these do show that a physiological price is paid for this change (7, 8). Once an organism acquires resistance through mutation, acquisition of resistance genes via plasmids, transposons and bacteriophages the initial physiological defect is compensated by the antibiotic selective pressure, which balances the physiological deficit imposed by the resistant mutation or additional DNA (8, 9).
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Abstract
The pathogenesis of pneumococcal infection is a complex interplay between pneumococcal virulence determinants and the host immune response. Molecular studies have considerably advanced our knowledge and understanding of the precise structures and functions of the different determinants and their pathogenic roles. This review describes the mechanisms by which pneumococci attach, invade, evade lung defences and cause severe disease. Better understanding of the critical steps in this complex process will enable more effective clinical intervention to be developed to reduce the mortality exacted by this versatile pathogen.
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