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A Preliminary Study on Public Health Implications of Avian Tuberculosis in Selected Districts of the Oromia Region, Ethiopia. Vet Med Int 2021; 2021:6331599. [PMID: 34691382 PMCID: PMC8528574 DOI: 10.1155/2021/6331599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 08/23/2021] [Accepted: 09/22/2021] [Indexed: 11/28/2022] Open
Abstract
Background Avian tuberculosis is a zoonotic disease which remains a problem in extensive poultry production systems under which chickens scavenge for survival in unhygienic environments. Methodology. A cross-sectional study was conducted from November 2016 to June 2017 at high-land areas of Gerar Jarso and Ada'a and Boset districts located at mid and low altitudes of Oromia, Ethiopia, respectively, to assess the perception of farmers on the occurrence of avian tuberculosis in chickens and its public health implications using a semistructured questionnaire. Result The study evidenced poor awareness of the farmers, as only 11% (10/91) of them had well-perceived occurrence of the disease in chickens and its risk of zoonosis. Conclusion Hence, it revealed that there is poor public perception on the occurrence as well as public health implications of avian tuberculosis, demanding further studies for verification and technical interventions.
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Miller JM, Binnicker MJ, Campbell S, Carroll KC, Chapin KC, Gilligan PH, Gonzalez MD, Jerris RC, Kehl SC, Patel R, Pritt BS, Richter SS, Robinson-Dunn B, Schwartzman JD, Snyder JW, Telford S, Theel ES, Thomson RB, Weinstein MP, Yao JD. A Guide to Utilization of the Microbiology Laboratory for Diagnosis of Infectious Diseases: 2018 Update by the Infectious Diseases Society of America and the American Society for Microbiology. Clin Infect Dis 2018; 67:e1-e94. [PMID: 29955859 PMCID: PMC7108105 DOI: 10.1093/cid/ciy381] [Citation(s) in RCA: 288] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Accepted: 04/28/2018] [Indexed: 12/12/2022] Open
Abstract
The critical nature of the microbiology laboratory in infectious disease diagnosis calls for a close, positive working relationship between the physician/advanced practice provider and the microbiologists who provide enormous value to the healthcare team. This document, developed by experts in laboratory and adult and pediatric clinical medicine, provides information on which tests are valuable and in which contexts, and on tests that add little or no value for diagnostic decisions. This document presents a system-based approach rather than specimen-based approach, and includes bloodstream and cardiovascular system infections, central nervous system infections, ocular infections, soft tissue infections of the head and neck, upper and lower respiratory infections, infections of the gastrointestinal tract, intra-abdominal infections, bone and joint infections, urinary tract infections, genital infections, and other skin and soft tissue infections; or into etiologic agent groups, including arthropod-borne infections, viral syndromes, and blood and tissue parasite infections. Each section contains introductory concepts, a summary of key points, and detailed tables that list suspected agents; the most reliable tests to order; the samples (and volumes) to collect in order of preference; specimen transport devices, procedures, times, and temperatures; and detailed notes on specific issues regarding the test methods, such as when tests are likely to require a specialized laboratory or have prolonged turnaround times. In addition, the pediatric needs of specimen management are also emphasized. There is intentional redundancy among the tables and sections, as many agents and assay choices overlap. The document is intended to serve as a guidance for physicians in choosing tests that will aid them to quickly and accurately diagnose infectious diseases in their patients.
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Affiliation(s)
| | - Matthew J Binnicker
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | | | - Karen C Carroll
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | | | - Peter H Gilligan
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill
| | - Mark D Gonzalez
- Department of Pathology, Children’s Healthcare of Atlanta, Georgia
| | - Robert C Jerris
- Department of Pathology, Children’s Healthcare of Atlanta, Georgia
| | | | - Robin Patel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Bobbi S Pritt
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | | | - Barbara Robinson-Dunn
- Department of Pathology and Laboratory Medicine, Beaumont Health, Royal Oak, Michigan
| | | | - James W Snyder
- Department of Pathology and Laboratory Medicine, University of Louisville, Kentucky
| | - Sam Telford
- Department of Infectious Disease and Global Health, Tufts University, North Grafton, Massachusetts
| | - Elitza S Theel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Richard B Thomson
- Department of Pathology and Laboratory Medicine, NorthShore University HealthSystem, Evanston, Illinois
| | - Melvin P Weinstein
- Departments of Medicine and Pathology & Laboratory Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey
| | - Joseph D Yao
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
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Shah I, Shah F. Nontuberculous mycobacterial empyema in an immunocompetent child. INDIAN J PATHOL MICR 2018; 61:141-142. [DOI: 10.4103/ijpm.ijpm_586_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Avian Mycobacteriosis: Still Existing Threat to Humans. BIOMED RESEARCH INTERNATIONAL 2016; 2016:4387461. [PMID: 27556033 PMCID: PMC4983314 DOI: 10.1155/2016/4387461] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/31/2016] [Accepted: 06/19/2016] [Indexed: 12/26/2022]
Abstract
The nontuberculous mycobacteria are typically environmental organisms residing in soil and water. These microorganisms can cause a wide range of clinical diseases; pulmonary disease is most frequent, followed by lymphadenitis in children, skin and soft tissue disease, and rare extra pulmonary or disseminated infections. Mycobacterium avium complex is the second most common cause of pulmonary mycobacterioses after M. tuberculosis. This review covers the clinical and laboratory diagnosis of infection caused by the members of this complex and particularities for the treatment of different disease types and patient populations.
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Virulence and immune response induced by Mycobacterium avium complex strains in a model of progressive pulmonary tuberculosis and subcutaneous infection in BALB/c mice. Infect Immun 2013; 81:4001-12. [PMID: 23959717 DOI: 10.1128/iai.00150-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The genus Mycobacterium comprises more than 150 species, including important pathogens for humans which cause major public health problems. The vast majority of efforts to understand the genus have been addressed in studies with Mycobacterium tuberculosis. The biological differentiation between M. tuberculosis and nontuberculous mycobacteria (NTM) is important because there are distinctions in the sources of infection, treatments, and the course of disease. Likewise, the importance of studying NTM is not only due to its clinical significance but also due to the mechanisms by which some species are pathogenic while others are not. Mycobacterium avium complex (MAC) is the most important group of NTM opportunistic pathogens, since it is the second largest medical complex in the genus after the M. tuberculosis complex. Here, we evaluated the virulence and immune response of M. avium subsp. avium and Mycobacterium colombiense, using experimental models of progressive pulmonary tuberculosis and subcutaneous infection in BALB/c mice. Mice infected intratracheally with a high dose of MAC strains showed high expression of tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase with rapid bacillus elimination and numerous granulomas, but without lung consolidation during late infection in coexistence with high expression of anti-inflammatory cytokines. In contrast, subcutaneous infection showed high production of the proinflammatory cytokines TNF-α and gamma interferon with relatively low production of anti-inflammatory cytokines such as interleukin-10 (IL-10) or IL-4, which efficiently eliminate the bacilli but maintain extensive inflammation and fibrosis. Thus, MAC infection evokes different immune and inflammatory responses depending on the MAC species and affected tissue.
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Baron EJ, Miller JM, Weinstein MP, Richter SS, Gilligan PH, Thomson RB, Bourbeau P, Carroll KC, Kehl SC, Dunne WM, Robinson-Dunn B, Schwartzman JD, Chapin KC, Snyder JW, Forbes BA, Patel R, Rosenblatt JE, Pritt BS. A guide to utilization of the microbiology laboratory for diagnosis of infectious diseases: 2013 recommendations by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM)(a). Clin Infect Dis 2013; 57:e22-e121. [PMID: 23845951 PMCID: PMC3719886 DOI: 10.1093/cid/cit278] [Citation(s) in RCA: 313] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 04/22/2013] [Indexed: 12/18/2022] Open
Abstract
The critical role of the microbiology laboratory in infectious disease diagnosis calls for a close, positive working relationship between the physician and the microbiologists who provide enormous value to the health care team. This document, developed by both laboratory and clinical experts, provides information on which tests are valuable and in which contexts, and on tests that add little or no value for diagnostic decisions. Sections are divided into anatomic systems, including Bloodstream Infections and Infections of the Cardiovascular System, Central Nervous System Infections, Ocular Infections, Soft Tissue Infections of the Head and Neck, Upper Respiratory Infections, Lower Respiratory Tract infections, Infections of the Gastrointestinal Tract, Intraabdominal Infections, Bone and Joint Infections, Urinary Tract Infections, Genital Infections, and Skin and Soft Tissue Infections; or into etiologic agent groups, including Tickborne Infections, Viral Syndromes, and Blood and Tissue Parasite Infections. Each section contains introductory concepts, a summary of key points, and detailed tables that list suspected agents; the most reliable tests to order; the samples (and volumes) to collect in order of preference; specimen transport devices, procedures, times, and temperatures; and detailed notes on specific issues regarding the test methods, such as when tests are likely to require a specialized laboratory or have prolonged turnaround times. There is redundancy among the tables and sections, as many agents and assay choices overlap. The document is intended to serve as a reference to guide physicians in choosing tests that will aid them to diagnose infectious diseases in their patients.
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Affiliation(s)
- Ellen Jo Baron
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA.
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Diversity, community composition, and dynamics of nonpigmented and late-pigmenting rapidly growing mycobacteria in an urban tap water production and distribution system. Appl Environ Microbiol 2013; 79:5498-508. [PMID: 23835173 DOI: 10.1128/aem.00900-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nonpigmented and late-pigmenting rapidly growing mycobacteria (RGM) have been reported to commonly colonize water production and distribution systems. However, there is little information about the nature and distribution of RGM species within the different parts of such complex networks or about their clustering into specific RGM species communities. We conducted a large-scale survey between 2007 and 2009 in the Parisian urban tap water production and distribution system. We analyzed 1,418 water samples from 36 sites, covering all production units, water storage tanks, and distribution units; RGM isolates were identified by using rpoB gene sequencing. We detected 18 RGM species and putative new species, with most isolates being Mycobacterium chelonae and Mycobacterium llatzerense. Using hierarchical clustering and principal-component analysis, we found that RGM were organized into various communities correlating with water origin (groundwater or surface water) and location within the distribution network. Water treatment plants were more specifically associated with species of the Mycobacterium septicum group. On average, M. chelonae dominated network sites fed by surface water, and M. llatzerense dominated those fed by groundwater. Overall, the M. chelonae prevalence index increased along the distribution network and was associated with a correlative decrease in the prevalence index of M. llatzerense, suggesting competitive or niche exclusion between these two dominant species. Our data describe the great diversity and complexity of RGM species living in the interconnected environments that constitute the water production and distribution system of a large city and highlight the prevalence index of the potentially pathogenic species M. chelonae in the distribution network.
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Cooccurrence of free-living amoebae and nontuberculous Mycobacteria in hospital water networks, and preferential growth of Mycobacterium avium in Acanthamoeba lenticulata. Appl Environ Microbiol 2013; 79:3185-92. [PMID: 23475613 DOI: 10.1128/aem.03823-12] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The incidence of lung and other diseases due to nontuberculous mycobacteria (NTM) is increasing. NTM sources include potable water, especially in households where NTM populate pipes, taps, and showerheads. NTM share habitats with free-living amoebae (FLA) and can grow in FLA as parasites or as endosymbionts. FLA containing NTM may form cysts that protect mycobacteria from disinfectants and antibiotics. We first assessed the presence of FLA and NTM in water and biofilm samples collected from a hospital, confirming the high prevalence of NTM and FLA in potable water systems, particularly in biofilms. Acanthamoeba spp. (genotype T4) were mainly recovered (8/17), followed by Hartmannella vermiformis (7/17) as well as one isolate closely related to the genus Flamella and one isolate only distantly related to previously described species. Concerning mycobacteria, Mycobacterium gordonae was the most frequently found isolate (9/17), followed by Mycobacterium peregrinum (4/17), Mycobacterium chelonae (2/17), Mycobacterium mucogenicum (1/17), and Mycobacterium avium (1/17). The propensity of Mycobacterium avium hospital isolate H87 and M. avium collection strain 104 to survive and replicate within various FLA was also evaluated, demonstrating survival of both strains in all amoebal species tested but high replication rates only in Acanthamoeba lenticulata. As A. lenticulata was frequently recovered from environmental samples, including drinking water samples, these results could have important consequences for the ecology of M. avium in drinking water networks and the epidemiology of disease due to this species.
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Vázquez N, Rekka S, Gliozzi M, Feng CG, Amarnath S, Orenstein JM, Wahl SM. Modulation of innate host factors by Mycobacterium avium complex in human macrophages includes interleukin 17. J Infect Dis 2012; 206:1206-17. [PMID: 22930805 DOI: 10.1093/infdis/jis492] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Although opportunistic infections due to Mycobacterium avium complex (MAC) have been less common since the introduction of highly active antiretroviral therapy, globally, human immunodeficiency virus-1 (HIV-1)-positive patients remain predisposed to these infections. Absence of a properly functioning acquired immune response allows MAC persistence within macrophages localized in lymph nodes coinfected with HIV and MAC. Although a deficiency in interferon γ appears to play a part in the ability of MAC to deflect the macrophage-associated antimicrobial attack, questions about this process remain. Our study examines the ability of MAC to regulate interleukin 17 (IL-17), a proinflammatory cytokine involved in host cell recruitment. METHODS Coinfected lymph nodes were examined for IL-17 by immunohistochemical analysis. In vitro, macrophages exposed to mycobacteria were evaluated for transcription activities, proteins, and signaling pathways responsible for IL-17 expression. Infected macrophages were also analyzed for expression of interleukin 21 (IL-21) and negative regulators of immune responses. RESULTS Infection of macrophages triggered synthesis of IL-17, correlating with IL-17 expression by macrophages in coinfected lymph nodes. Infected macrophages exposed to exogenous IL-17 expressed CXCL10, which favors recruitment of new macrophages as targets for infection. Blockade of nuclear factor κ-light-chain-enhancer of activated B cells and mitogen-activated protein kinase pathways suppressed mycobacteria-induced IL-17 expression. MAC triggered expression of IL-21, IRF4, and STAT3 genes related to IL-17 regulation, as well as expression of the negative immunoregulators CD274(PD-L1) and suppressors of cytokine signaling. CONCLUSIONS MAC-infected macrophages can provide an alternative source for IL-17 that favors accumulation of new targets for perpetuating bacterial and viral infection while suppressing host antimicrobial immune responses.
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Affiliation(s)
- Nancy Vázquez
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, Bethesda, MD 20892-4352, USA.
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Nontuberculous mycobacterial infections in cancer patients in a medical center in Taiwan, 2005–2008. Diagn Microbiol Infect Dis 2012; 72:161-5. [DOI: 10.1016/j.diagmicrobio.2011.10.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 10/10/2011] [Accepted: 10/25/2011] [Indexed: 01/15/2023]
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[Non-tuberculous mycobacterial infection in patients with non-cystic fibrosis bronchiectasias]. Rev Clin Esp 2011; 212:127-30. [PMID: 22119262 DOI: 10.1016/j.rce.2011.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 07/25/2011] [Accepted: 08/11/2011] [Indexed: 11/20/2022]
Abstract
AIMS To know the characteristics and prevalence of non-tuberculous mycobacterial infection infection in patients with non-cystic fibrosis bronchiectasis. PATIENTS AND METHODS A retrospective descriptive study of NCFB adult patients whose disease had been followed-up for at least two years was performed. RESULTS A total of 68 subjects were included, 50 females (73.5%), with mean age of 63.31± 16.2 years. The most frequent etiology of the non-cystic fibrosis bronchiectasis was COPD in 28 cases (41.2%) with a light-moderate pulmonary involvement and Pseudomonas aeruginosa (P. aeruginosa) colonization (70.6%). Seven patients (10.3%) had MNT infection, six of whom had Mycobacterium avium complex (7.35%). Four patients (57.14%) were treated. In the infected patients, P. aeruginosa and the use of inhaled steroids were observed with less frequency. There were no significant differences between the infected and non-infected patients in relation to spirometric values. CONCLUSIONS The non-cystic fibrosis bronchiectasis could be considered a risk factor for non-tuberculous mycobacterial infection.
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Song Y, Wu J, Yan H, Chen J. Peritoneal dialysis-associated nontuberculous mycobacterium peritonitis: a systematic review of reported cases. Nephrol Dial Transplant 2011; 27:1639-44. [PMID: 21891775 DOI: 10.1093/ndt/gfr504] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Peritonitis caused by nontuberculous mycobacterium (NTM) is an important complication in peritoneal dialysis (PD) patients. METHODS Cases of PD complicated by NTM peritonitis reported in the English language literature were identified in the PubMed database. The characteristics of these cases were reviewed. RESULTS In 41 articles, we identified 57 cases of PD-associated NTM peritonitis in patients ranging from 5 to 82 years. The prevalent clinical findings of these cases were fever, abdominal pain, cloudy fluid and an elevated leukocyte count in peritoneal fluid. These findings were non-specific and could not be differentiated from symptoms caused by Mycobacterium tuberculosis or other bacteria. The majority of these cases received empirical antibacterial therapy before diagnosis of NTM peritonitis. Isolates in more than half of the peritonitis cases were the rapidly growing Mycobacterium, Mycobacterium fortuitum (38.6%) and Mycobacterium chelonae (14.0%). In most cases, PD catheters were removed and experience with non-removal was limited. CONCLUSION Diagnosis of NTM infection should be considered in PD patients with peritonitis that are culture negative or refractory to empirical antibiotic therapy.
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Affiliation(s)
- Yan Song
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hanghzou, People’s Republic of China
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Lai CC, Tan CK, Lin SH, Liu WL, Liao CH, Huang YT, Hsueh PR. Clinical significance of nontuberculous mycobacteria isolates in elderly Taiwanese patients. Eur J Clin Microbiol Infect Dis 2011; 30:779-83. [PMID: 21240651 DOI: 10.1007/s10096-011-1155-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2010] [Revised: 12/21/2010] [Accepted: 12/25/2010] [Indexed: 01/15/2023]
Abstract
The aim of this study was to investigate the clinical significance of nontuberculous mycobacteria (NTM) isolates in elderly Taiwanese patients. From 2004 through 2008, patients >65 years old with NTM isolation were identified. The definitions of NTM disease followed the American Thoracic Society and Infectious Disease Society of America (ATS/IDSA) criteria. Among the 3,175 NTM isolates, Mycobacterium avium complex (MAC; n = 1,118, 35.2%) was the most prevalent species, followed by M. abscessus (n = 545, 17.2%). Among the 1,633 elderly patients with NTM isolates, the most prevalent NTM species were MAC (n = 592, 36.3%) and M. fortuitum complex (n = 311, 19.0%). NTM colonization was found in 1,339 (80.4%) patients and only 326 (19.6%) patients had NTM diseases. During the study period, the annual incidence rates (per 100,000 inpatients and outpatients) of NTM colonization and disease both increased significantly (p < 0.0001) from 10.5 to 15.8 and from 2.1 to 4.3, respectively. Isolated pulmonary NTM infections compromised 294 (90.2%) of the 326 elderly cases of NTM disease. In conclusion, this study found an increasing trend in the incidence of both NTM isolates and NTM diseases among elderly Taiwanese patients. MAC and M. abscessus were the most frequent species causing various types of NTM disease.
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Affiliation(s)
- C-C Lai
- Department of Intensive Care Medicine, Chi Mei Medical Center, Liouying, Tainan, Taiwan
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Determination of genotypic diversity of Mycobacterium avium subspecies from human and animal origins by mycobacterial interspersed repetitive-unit-variable-number tandem-repeat and IS1311 restriction fragment length polymorphism typing methods. J Clin Microbiol 2010; 48:1026-34. [PMID: 20107094 DOI: 10.1128/jcm.01869-09] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Members of the Mycobacterium avium complex (MAC) are ubiquitous bacteria that can be found in water, food, and other environmental samples and are considered opportunistic pathogens for numerous animal species, mainly birds and pigs, as well as for humans. We have recently demonstrated the usefulness of a PCR-based mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) typing for the molecular characterization of M. avium subsp. paratuberculosis and M. avium strains exclusively isolated from AIDS patients. In the present study we extended our analysis, based on eight MIRU-VNTR markers, to a strain collection comprehensively comprising the other M. avium subspecies, including M. avium subsp. avium, M. avium subsp. hominissuis, and M. avium subsp. silvaticum, isolated from numerous animal species, HIV-positive and HIV-negative humans, and environmental sources. All strains were fully typeable, with the discriminatory index being 0.885, which is almost equal to that obtained by IS1311 restriction fragment length polymorphism (RFLP) typing as a reference. In contrast to IS1311 RFLP typing, MIRU-VNTR typing was able to further discriminate M. avium subsp. avium strains. MIRU-VNTR alleles strongly associated with or specific for M. avium subspecies were detected in several markers. Moreover, the MIRU-VNTR typing-based results were consistent with a scenario of the independent evolution of M. avium subsp. avium/M. avium subsp. silvaticum and M. avium subsp. paratuberculosis from M. avium subsp. hominissuis, previously proposed on the basis of multilocus sequence analysis. MIRU-VNTR typing therefore appears to be a convenient typing method capable of distinguishing the three main subspecies and strains of the complex and providing new epidemiological knowledge on MAC.
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Abstract
Despite using modern microbiological diagnostic approaches, the aetiological agents of pneumonia remain unidentified in about 50% of cases. Some bacteria that grow poorly or not at all in axenic media used in routine clinical bacteriology laboratory but which can develop inside amoebae may be the agents of these lower respiratory tract infections (RTIs) of unexplained aetiology. Such amoebae-resisting bacteria, which coevolved with amoebae to resist their microbicidal machinery, may have developed virulence traits that help them survive within human macrophages, i.e. the first line of innate immune defence in the lung. We review here the current evidence for the emerging pathogenic role of various amoebae-resisting microorganisms as agents of RTIs in humans. Specifically, we discuss the emerging pathogenic roles of Legionella-like amoebal pathogens, novel Chlamydiae (Parachlamydia acanthamoebae, Simkania negevensis), waterborne mycobacteria and Bradyrhizobiaceae (Bosea and Afipia spp.).
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Affiliation(s)
- Frédéric Lamoth
- Infectious Diseases Service, University of Lausanne, Lausanne, Switzerland
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