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Microbiology and Molecular Biology... Mar 2016Actinobacteria are Gram-positive bacteria with high G+C DNA content that constitute one of the largest bacterial phyla, and they are ubiquitously distributed in both... (Review)
Review
Actinobacteria are Gram-positive bacteria with high G+C DNA content that constitute one of the largest bacterial phyla, and they are ubiquitously distributed in both aquatic and terrestrial ecosystems. Many Actinobacteria have a mycelial lifestyle and undergo complex morphological differentiation. They also have an extensive secondary metabolism and produce about two-thirds of all naturally derived antibiotics in current clinical use, as well as many anticancer, anthelmintic, and antifungal compounds. Consequently, these bacteria are of major importance for biotechnology, medicine, and agriculture. Actinobacteria play diverse roles in their associations with various higher organisms, since their members have adopted different lifestyles, and the phylum includes pathogens (notably, species of Corynebacterium, Mycobacterium, Nocardia, Propionibacterium, and Tropheryma), soil inhabitants (e.g., Micromonospora and Streptomyces species), plant commensals (e.g., Frankia spp.), and gastrointestinal commensals (Bifidobacterium spp.). Actinobacteria also play an important role as symbionts and as pathogens in plant-associated microbial communities. This review presents an update on the biology of this important bacterial phylum.
Topics: Actinobacteria; Anti-Bacterial Agents; Antifungal Agents; Biological Products; Herbicides; Insecticides; Microbial Interactions; Phylogeny; Pigments, Biological; Spores, Bacterial
PubMed: 26609051
DOI: 10.1128/MMBR.00019-15 -
Clinical Microbiology Reviews Apr 2017Whipple's disease is a rare infectious disease that can be fatal if left untreated. The disease is caused by infection with , a bacterium that may be more common than... (Review)
Review
Whipple's disease is a rare infectious disease that can be fatal if left untreated. The disease is caused by infection with , a bacterium that may be more common than was initially assumed. Most patients present with nonspecific symptoms, and as routine cultivation of the bacterium is not feasible, it is difficult to diagnose this infection. On the other hand, due to the generic symptoms, infection with this bacterium is actually quite often in the differential diagnosis. The gold standard for diagnosis used to be periodic acid-Schiff (PAS) staining of duodenal biopsy specimens, but PAS staining has a poor specificity and sensitivity. The development of molecular techniques has resulted in more convenient methods for detecting infections, and this has greatly improved the diagnosis of this often missed infection. In addition, the molecular detection of has resulted in an increase in knowledge about its pathogenicity, and this review gives an overview of the new insights in epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of infections.
Topics: Anti-Bacterial Agents; Humans; Tropheryma; Whipple Disease
PubMed: 28298472
DOI: 10.1128/CMR.00033-16 -
Clinical Microbiology Reviews Jan 2015A pure bacterial culture remains essential for the study of its virulence, its antibiotic susceptibility, and its genome sequence in order to facilitate the... (Review)
Review
A pure bacterial culture remains essential for the study of its virulence, its antibiotic susceptibility, and its genome sequence in order to facilitate the understanding and treatment of caused diseases. The first culture conditions empirically varied incubation time, nutrients, atmosphere, and temperature; culture was then gradually abandoned in favor of molecular methods. The rebirth of culture in clinical microbiology was prompted by microbiologists specializing in intracellular bacteria. The shell vial procedure allowed the culture of new species of Rickettsia. The design of axenic media for growing fastidious bacteria such as Tropheryma whipplei and Coxiella burnetii and the ability of amoebal coculture to discover new bacteria constituted major advances. Strong efforts associating optimized culture media, detection methods, and a microaerophilic atmosphere allowed a dramatic decrease of the time of Mycobacterium tuberculosis culture. The use of a new versatile medium allowed an extension of the repertoire of archaea. Finally, to optimize the culture of anaerobes in routine bacteriology laboratories, the addition of antioxidants in culture media under an aerobic atmosphere allowed the growth of strictly anaerobic species. Nevertheless, among usual bacterial pathogens, the development of axenic media for the culture of Treponema pallidum or Mycobacterium leprae remains an important challenge that the patience and innovations of cultivators will enable them to overcome.
Topics: Bacteria; Bacterial Infections; Bacteriological Techniques; Culture Media; History, 20th Century; History, 21st Century; Microbiology
PubMed: 25567228
DOI: 10.1128/CMR.00110-14 -
Journal of Clinical Microbiology Jul 2022Next-generation sequencing (NGS) workflows applied to bronchoalveolar lavage (BAL) fluid specimens could enhance the detection of respiratory pathogens, although optimal...
Next-generation sequencing (NGS) workflows applied to bronchoalveolar lavage (BAL) fluid specimens could enhance the detection of respiratory pathogens, although optimal approaches are not defined. This study evaluated the performance of the Respiratory Pathogen ID/AMR (RPIP) kit (Illumina, Inc.) with automated Explify bioinformatic analysis (IDbyDNA, Inc.), a targeted NGS workflow enriching specific pathogen sequences and antimicrobial resistance (AMR) markers, and a complementary untargeted metagenomic workflow with in-house bioinformatic analysis. Compared to a composite clinical standard consisting of provider-ordered microbiology testing, chart review, and orthogonal testing, both workflows demonstrated similar performances. The overall agreement for the RPIP targeted workflow was 65.6% (95% confidence interval, 59.2 to 71.5%), with a positive percent agreement (PPA) of 45.9% (36.8 to 55.2%) and a negative percent agreement (NPA) of 85.7% (78.1 to 91.5%). The overall accuracy for the metagenomic workflow was 67.1% (60.9 to 72.9%), with a PPA of 56.6% (47.3 to 65.5%) and an NPA of 77.2% (68.9 to 84.1%). The approaches revealed pathogens undetected by provider-ordered testing (Ureaplasma parvum, Tropheryma whipplei, severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2], rhinovirus, and cytomegalovirus [CMV]), although not all pathogens detected by provider-ordered testing were identified by the NGS workflows. The RPIP targeted workflow required more time and reagents for library preparation but streamlined bioinformatic analysis, whereas the metagenomic assay was less demanding technically but required complex bioinformatic analysis. The results from both workflows were interpreted utilizing standardized criteria, which is necessary to avoid reporting nonpathogenic organisms. The RPIP targeted workflow identified AMR markers associated with phenotypic resistance in some bacteria but incorrectly identified genes in Pseudomonas aeruginosa as being associated with carbapenem resistance. These workflows could serve as adjunctive testing with, but not as a replacement for, standard microbiology techniques.
Topics: Bronchoalveolar Lavage Fluid; COVID-19; Communicable Diseases; High-Throughput Nucleotide Sequencing; Humans; Metagenomics; SARS-CoV-2; Workflow
PubMed: 35695488
DOI: 10.1128/jcm.00526-22 -
Viszeralmedizin Jun 2014Whipple's disease (WD) is rarely the cause of a malabsorption syndrome. The disease is a chronic infection of the intestinal mucosa with the bacterium Tropheryma... (Review)
Review
BACKGROUND
Whipple's disease (WD) is rarely the cause of a malabsorption syndrome. The disease is a chronic infection of the intestinal mucosa with the bacterium Tropheryma whipplei, which leads to a lymphostasis with an impaired absorption of the nutrition. Due to its low incidence (1:1,000,000) and the non-specific early symptoms, the disease is often diagnosed only after many years.
METHODS
Based on a selective literature review and the clinical experience of the authors, the current knowledge of WD regarding pathogenesis, clinical presentation, diagnosis, and therapy are presented in this paper.
RESULTS
Recent studies suggest that a host-specific dysfunction of the intestinal macrophages is responsible for the chronic infection with T. whipplei. Prior to patients reporting symptoms of a malabsorption syndrome (chronic diarrhea/steatorhea, weight loss), they often suffer from non-specific symptoms (polyarthralgia, fever, fatigue) for many years. Misdiagnoses such as seronegative polyarthritis are frequent. Furthermore, neurological, cardiac, ocular, or dermatological symptoms may occur. The standard method concerning diagnosis is the detection of PAS(periodic acid-Schiff)-positive macrophages in the affected tissues. Immunohistochemical staining and PCR(polymerase chain reaction)-based genetic analysis increase the sensitivity and specificity of conventional detection methods. Endoscopically, the intestinal mucosa appears edematous with lymphangiectasias, enlarged villi, and white-yellowish ring-like structures. The German treatment recommendations include a two-week intravenous induction therapy with ceftriaxone, which is followed by a three-month oral maintenance therapy with trimethoprim/sulfamethoxazole.
CONCLUSION
WD is rarely responsible for a malabsorption syndrome. However, if WD is not recognized, the disease can be lethal. New diagnostic methods and prospectively approved therapeutic concepts allow an adequate treatment of the patient. Due to the host-specific susceptibility to T. whipplei, a lifelong follow-up is necessary.
PubMed: 26288590
DOI: 10.1159/000363781 -
Clinical Microbiology Reviews Jul 2001Whipple's disease is a rare bacterial infection that may involve any organ system in the body. It occurs primarily in Caucasian males older than 40 years. The... (Review)
Review
Whipple's disease is a rare bacterial infection that may involve any organ system in the body. It occurs primarily in Caucasian males older than 40 years. The gastrointestinal tract is the most frequently involved organ, with manifestations such as abdominal pain, malabsorption syndrome with diarrhea, and weight loss. Other signs include low-grade fever, lymphadenopathy, skin hyperpigmentation, endocarditis, pleuritis, seronegative arthritis, uveitis, spondylodiscitis, and neurological manifestations, and these signs may occur in the absence of gastrointestinal manifestations. Due to the wide variability of manifestations, clinical diagnosis is very difficult and is often made only years or even decades after the initial symptoms have appeared. Trimethoprim-sulfamethoxazole for at least 1 year is usually considered adequate to eradicate the infection. The microbiological diagnosis of this insidious disease is rendered difficult by the virtual lack of culture and serodiagnostic methods. It is usually based on the demonstration of periodic acid-Schiff-positive particles in infected tissues and/or the presence of bacteria with an unusual trilaminar cell wall ultrastructure by electron microscopy. Recently, the Whipple bacteria have been characterized at the molecular level by amplification of their 16S rRNA gene(s). Phylogenetic analysis of these sequences revealed a new bacterial species related to the actinomycete branch which was named "Tropheryma whippelli." Based on its unique 16S ribosomal DNA (rDNA) sequence, species-specific primers were selected for the detection of the organism in clinical specimens by PCR. This technique is currently used as one of the standard methods for establishing the diagnosis of Whipple's disease. Specific and broad-spectrum PCR amplifications mainly but not exclusively from extraintestinal specimens have significantly improved diagnosis, being more sensitive than histopathologic analysis. However, "T. whippelii" DNA has also been found in persons without clinical and histological evidence of Whipple's disease. It is unclear whether these patients are true asymptomatic carriers or whether differences in virulence exist among strains of "T. whippelii" that might account for the variable clinical manifestations. So far, six different "T. whippelii" subtypes have been found by analysis of their 16S-23S rDNA spacer region. Further studies of the pathogen "T. whippelii" as well as the host immune response are needed to fully understand this fascinating disease. The recent cultivation of the organisms is a promising major step in this direction.
Topics: Actinobacteria; Base Sequence; DNA, Ribosomal Spacer; Female; Humans; Male; Molecular Sequence Data; RNA, Ribosomal, 16S; RNA, Ribosomal, 23S; Whipple Disease
PubMed: 11432814
DOI: 10.1128/CMR.14.3.561-583.2001 -
Surgical Neurology International 2022Whipple disease (WD) is an infection caused by , which might present in three different forms: classical, localized, and isolated in the central nervous system (CNS). (Review)
Review
BACKGROUND
Whipple disease (WD) is an infection caused by , which might present in three different forms: classical, localized, and isolated in the central nervous system (CNS).
METHODS
We report the result of a systematic review of the literature on WD unusually presenting with exclusively neurological symptoms, including two previously unpublished cases. A description of two cases with isolated CNS WD was performed, as well as a literature search in , and .
RESULTS
Two male adult patients presented with exclusively neurological symptomatology. Both magnetic resonance imaging (MRI) showed an intracranial mass suggestive of brain tumor. The histopathological examination was consistent with WD, with no systemic involvement. In the review of the literature, 35 cases of isolated CNS WD were retrieved. The median age at diagnosis was 43.5 (IQR 31.5-51.5). In 13 patients, the MRI showed a brain mass consistent with a brain tumor. The most common finding in the biopsy was the periodic-acid Schiff-stained foamy macrophages. Only five cases presented the pathognomonic sign of oculomasticatory myorhythmia. Thirteen cases had an adverse outcome that resulted in death during follow-up, whereas another 13 improved. The other nine patients remained stable or presented moderate improvement.
CONCLUSION
Isolated CNS WD is a rare disease that should be considered among the differential diagnosis of CNS mass lesions. Brain biopsy is necessary to establish the diagnosis. It is stressed in the literature that an extended antibiotic course is required to prevent relapses and to control the disease.
PubMed: 36324907
DOI: 10.25259/SNI_591_2022 -
Gut Microbes 2021, is an actinobacterium that causes different infections in humans, including Whipple's disease. The bacterium infects and replicates in macrophages, leading to a...
, is an actinobacterium that causes different infections in humans, including Whipple's disease. The bacterium infects and replicates in macrophages, leading to a Th2-biased immune response. Previous studies have shown that harbors complex surface glycoproteins with evidence of sialylation. However, the exact contribution of these glycoproteins for infection and survival remains obscure. To address this, we characterized the bacterial glycoprofile and evaluated the involvement of human β-galactoside-binding lectins, Galectin-1 (Gal-1) and Galectin-3 (Gal-3) which are highly expressed by macrophages as receptors for bacterial glycans. glycoproteins harbor different sugars including glucose, mannose, fucose, β-galactose and sialic acid. Mass spectrometry identification revealed that these glycoproteins were membrane- and virulence-associated glycoproteins. Most of these glycoproteins are highly sialylated and N-glycosylated while some of them are rich in poly-N-acetyllactosamine (Poly-LAcNAc) and bind Gal-1 and Gal-3. modulates the expression and cellular distribution of Gal-1 and Gal-3. Although both galectins promote infection by enhancing bacterial cell entry, only Gal-3 is required for optimal bacterial uptake. Finally, we found that serum levels of Gal-1 and Gal-3 were altered in patients with infections as compared to healthy individuals, suggesting that galectins are also involved . Among membrane-associated proteins, poly-LacNAc rich-glycoproteins promote infection through interaction with galectins. modulates the expression of Gal-1 and Gal-3 both and . Drugs interfering with galectin-glycan interactions may provide new avenues for the treatment and diagnosis of infections.
Topics: Bacterial Proteins; Blood Proteins; Galactose; Galectin 1; Galectins; Glycoproteins; Glycosylation; Humans; Macrophages; Polysaccharides, Bacterial; Tropheryma; Virulence; Whipple Disease
PubMed: 33573443
DOI: 10.1080/19490976.2021.1884515 -
Diagnostic Pathology Jan 2022Immunohistochemistry (IHC) using monoclonal and polyclonal antibodies is a useful diagnostic method for detecting pathogen antigens in fixed tissues, complementing the... (Review)
Review
BACKGROUND
Immunohistochemistry (IHC) using monoclonal and polyclonal antibodies is a useful diagnostic method for detecting pathogen antigens in fixed tissues, complementing the direct diagnosis of infectious diseases by PCR and culture on fresh tissues. It was first implemented in a seminal publication by Albert Coons in 1941.
MAIN BODY
Of 14,198 publications retrieved from the PubMed, Google, Google Scholar and Science Direct databases up to December 2021, 230 were selected for a review of IHC techniques, protocols and results. The methodological evolutions of IHC and its application to the diagnosis of infectious diseases, more specifically lice-borne diseases, sexually transmitted diseases and skin infections, were critically examined. A total of 59 different pathogens have been detected once in 22 different tissues and organs; and yet non-cultured, fastidious and intracellular pathogens accounted for the vast majority of pathogens detected by IHC. Auto-IHC, incorporating patient serum as the primary antibody, applied to diseased heart valves surgically collected from blood culture-negative endocarditis patients, detected unidentified Gram-positive cocci and microorganisms which were subsequently identified as Coxiella burnetii, Bartonella quintana, Bartonella henselae and Tropheryma whipplei. The application of IHC to ancient tissues dated between the ends of the Ptolemaic period to over 70 years ago, have also contributed to paleomicrobiology diagnoses.
CONCLUSION
IHC plays an important role in diagnostic of infectious diseases in tissue samples. Paleo-auto-IHC derived from auto-IHC, is under development for detecting non-identified pathogens from ancient specimens.
Topics: Bartonella quintana; Communicable Diseases; Coxiella burnetii; Heart Valves; Humans; Polymerase Chain Reaction
PubMed: 35094696
DOI: 10.1186/s13000-022-01197-5