A novel insertion element from Mycobacterium avium, IS1245, is a specific target for analysis of strain relatedness

Guerrero, Carmen; Bernasconi, C.; Burki, D; Bodmer, Thomas; Telenti, Amalio

doi:10.1128/jcm.33.2.304-307.1995

Cited by 285 publications

(150 citation statements)

References 30 publications

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“…strain H87 [45]. The MAH 11 genome contains at least 14 copies of IS1245 (similar to MAH 104; [46]), but none of IS901 (associated with members of the MAC complex primarily infecting birds; [42, 47]). S2 Fig shows the position of MAH 11 in a phylogenetic tree (created using PHYLIP, http://evolution.genetics.washington.edu/phylip.html) together with 21 other M. avium genomes obtained from NCBI GenBank, including M. avium subsp.…”

Section: Resultsmentioning

confidence: 99%

Global assessment ofMycobacterium aviumsubspecieshominissuisgenetic requirement for growth and virulence

Dragset

Ioerger

Loevenich

et al. 2019

Preprint

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27 Nontuberculous mycobacterial infections caused by the opportunistic pathogen 28 Mycobacterium avium subsp. hominissuis (MAH) are currently receiving renewed 29 attention due to increased incidence combined with difficult treatment. Insights into 30 the disease-causing mechanisms of this species have been hampered by difficulties in 31 genetic manipulation of the bacteria. Here, we identified and sequenced a highly 32 transformable, virulent MAH clinical isolate susceptible to high-density transposon 33 mutagenesis, facilitating global gene disruption and subsequent investigation of MAH 34 gene function. By transposon insertion sequencing (TnSeq) of this strain, we defined 35 the MAH genome-wide genetic requirement for virulence and in vitro growth, and 36 organized ~3500 identified transposon mutants for hypothesis-driven research. The 37 majority (71 %) of the genes we identified as essential for MAH in vitro had a 38 growth-essential mutual ortholog in the related and highly virulent M. tuberculosis 39 (Mtb). However, passaging our library through a mouse model of infection revealed a 40 substantial number (54% of total hits) of novel virulence genes. Strikingly, > 97 % of 41 the MAH virulence genes had a mutual ortholog in Mtb. Two of the three virulence 42 genes specific to MAH (i.e. no Mtb mutual orthologs) were PPE proteins, a family of 43 proteins unique to mycobacteria and highly associated with virulence. Finally, we 44 validated novel genes as required for successful MAH infection; one encoding a 45 probable MFS transporter and another a hypothetical protein located in immediate 46 vicinity of six other identified virulence genes. In summary, we provide new, 47 fundamental insights into the underlying genetic requirement of MAH for growth and 48 host infection. 49 50 3 51 Author summary 52 Pulmonary disease caused by nontuberculous mycobacteria is increasing worldwide. 53 The majority of these infections are caused by the M. avium complex (MAC), 54 whereof >90% arise from Mycobacterium avium subsp. hominissuis (MAH).55 Treatment of MAH infections is currently difficult, with a combination of antibiotics 56 given for at least 12 months. To control MAH by improved therapy, prevention and 57 diagnostics, we need to understand the underlying mechanisms of infection. While 58 genetic manipulation of pathogens is crucial to study pathogenesis, M. avium (Mav) 59 has been found notoriously hard to engineer. Here, we identify an MAH strain highly 60 susceptible to high-density transposon mutagenesis and transformation, facilitating 61 genetic engineering and analysis of gene function. We provide crucial insights into 62 this strain's global genetic requirements for growth and infection. Surprisingly, we 63 find that the vast majority of genes required for MAH growth and virulence (96% and 64 97%, respectively) have mutual orthologs in the tuberculosis-causing pathogen M.65 tuberculosis (Mtb). However, we also find growth and virulence genes specific to 66 MAC species. Finally, we validate novel mycobacterial ...

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Section: Resultsmentioning

confidence: 99%

Global assessment ofMycobacterium aviumsubspecieshominissuisgenetic requirement for growth and virulence

Dragset

Ioerger

Loevenich

et al. 2019

Preprint

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“…Mycobacterium avium was isolated from the large and small intestine, lymph nodes, liver, spleen, and heart in 5/9 horses. PCRs for IS1245 (Guerrero et al 1995) and IS901 (Kunze et al 1991) were used to discriminate between M. avium ssp. avium and M. avium ssp.…”

Section: Post Mortem Examinationmentioning

confidence: 99%

Disseminated alimentary mycobacteriosis in the horse: a retrospective study of nine cases

Mönki

Hewetson

Hahn

et al. 2015

Equine Veterinary Education

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Summary This paper summarises the clinical findings of 9 cases of disseminated alimentary mycobacteriosis in horses presented at a Finnish referral equine hospital 2009–2014. Four of 9 horses were Standardbreds and 8/9 horses were male. The median age was 2 years, ranging from 6 months to 15 years. The duration of clinical signs before admission ranged from 2 weeks to 6 months. All horses demonstrated deterioration of the clinical signs after a protracted period of the disease and were finally subjected to euthanasia after poor response to multiple medical therapies. The most common complaints on admission were weight loss and diarrhoea (9/9), pyrexia (7/9), ventral oedema (7/9), lethargy (7/9) and inappetance (6/9). The most common clinicopathological abnormalities were hypoalbuminaemia and hyperfibrinogenaemia, which were present in all horses. Rectal biopsy specimens were examined from 5/9 horses and specimens were stained with Ziehl‐Nielsen (ZN). At rectal biopsy, mild multifocal neutrophilic or mild granulomatous proctitis was recognised in all 5 horses, but the ZN stain for mycobacteria was positive in only one biopsy. A liver biopsy was taken from one horse in which hepatomegaly was observed clinically and revealed marked granulomatous hepatitis with the presence of mycobacteria. The rectal biopsy from this horse was ZN negative. At post mortem examination, chronic, multifocal to coalescing granulomatous typhlocolitis and lymphadenitis were found in all horses with the small intestine less frequently involved. At histopathological examination of post mortem samples, a ZN stain was performed and intracellular acid‐fast bacilli were identified in macrophages and multinucleated giant cells in the large intestine, liver and lymph nodes in 9/9 horses and in the small intestine in 5/9 horses. Mycobacterium avium ssp. hominissuis was isolated in 5/9 horses from post mortem samples.

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“…Quantification was performed according to the plasmid quantification gradient diluted in range 5 9 10 5 -5 9 10 0 plasmid copies per qPCR reaction. For the calculation of MAH cell number, on average fifteen copies of IS1245 per MAH cell were assumed (Guerrero et al, 1995). The detection limit of the qPCR assay is five copies for IS1245 (Slana et al, 2010).…”

Section: Determination Of Mycobacterium Avium Subsp Hominissuis Viabmentioning

confidence: 99%

Survival of three Mycobacterium avium subsp. hominissuis isolates in fish products after hot smoking and frying

Klanicova

Lorencova

Makovcová

et al. 2012

Int J of Food Sci Tech

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Summary Fish mycobacteriosis should be considered as one possible means of transmission of mycobacterial infections to humans. In our study, we examined the survival of three field Mycobacterium avium subsp. hominissuis (MAH) isolates in fish meat during thermal processing technologies using culture and quantitative real‐time PCR (qPCR) methods. Minced carp meat mixture was artificially contaminated with known amount of MAH cells and survival and absolute numbers of MAH was monitored after hot smoking and frying. The viability of MAH was significantly lower after the frying process, whereas in response to hot smoking viable MAH cells could still be cultured even after 10 min at 70 °C. Significant differences in thermal stability were also observed among the three different MAH isolates. The human isolate was the most resistant, whereas the environmental isolate was the least resistant, which is probably due to host adaptability. In this work we confirmed that MAH can survive temperatures of 70 °C and thus can pose a risk to consumers.

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A novel insertion element from Mycobacterium avium, IS1245, is a specific target for analysis of strain relatedness

Cited by 285 publications

References 30 publications

Global assessment ofMycobacterium aviumsubspecieshominissuisgenetic requirement for growth and virulence

Global assessment ofMycobacterium aviumsubspecieshominissuisgenetic requirement for growth and virulence

Disseminated alimentary mycobacteriosis in the horse: a retrospective study of nine cases

Survival of three Mycobacterium avium subsp. hominissuis isolates in fish products after hot smoking and frying

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