Mycobacterium Avium Subsp. Avium Research Articles

Identification and Phylogenetic Analysis of Mycobacterium avium subsp. avium Strain Isolated from Cow

Mycobacterium avium subsp. avium (MAA) is the main tuberculosis pathogen of poultry and wild birds. MAA can also infect mammals such as pigs, cattle, and horses and can pose a threat to people with low immunity. Here, we describe the first identification of MAA strain HJW isolated from a cow in Jilin Province, China. The isolate was completely sequenced and a phylogenetic analysis of its relationship to members of the Mycobacterium avium complex (MAC) was performed. The results revealed that strain HJW was type MAA based on the analysis of insertion sequence amplification and whole genome sequencing. The HJW genome size was 4,961,843 bp with a GC content of 69.28%. The strain was genetically most closely related to the Mycobacterium avium subsp. avium strain DSM 44156. This study suggests that MAA may pose an infection risk to cattle and provides data support for the phylogeny of Mycobacterium avium.

Disseminated tuberculosis-like but atypical mycobacteriosis in a cat caused by Mycobacterium avium subsp. avium (MAA)

Disseminated tuberculosis-like but atypical mycobacteriosis in a cat caused by Mycobacterium avium subsp. avium (MAA)

Isolation of Mycobacterium avium and other nontuberculous mycobacteria in chickens and captive birds in peninsular Malaysia

BackgroundMycobacterium avium complex (MAC) causes a chronic infectious in the birds known as avian mycobacteriosis. Almost all species of the birds are susceptible to MAC which consists of two closely related species of mycobacteria, that is, M. avium and M. intracellulare. This study aimed to determine the occurrence of Mycobacterium avium subsp. avium (MAA) in chickens and captive birds in selected states of Peninsular Malaysia.ResultsA 300 fecal samples were collected from village chickens (n = 100), layer chickens (n = 100) and captive birds (n = 100). Fecal samples were split into two aliquots for microbiological and molecular detection of MAA. Microbiology detection consisted of microscopy (Ziehl-Neelsen staining) and culture of samples decontaminated with 1% Cetylperidinium chloride and vancomycin, nalidixic acid and amphotericin B (VNA) antibiotic cocktail [vancomycin (VAN) 100 μg/ml, nalidixic acid (NAL) 100 μg/ml and amphotericin B (AMB) 50 μg/ml] onto Löwenstein-Jensen (L-J). Molecular detection (PCR-IS901) was performed to detect MAA DNA from the feces and PCR-16S rRNA and IS901 for identification of genus Mycobacterium and Mycobacterium avium sub species avium isolated onto L-J. All samples (296) were AFB negative smear. M. avium was isolated in 0.3% (1/296) samples by culture and detected in 2.5% (6/242) samples by PCR (IS901). Other mycobacteria were found in 1.7% (5/296) chickens. Of five isolates, two were identified as Mycobacterium terrae and M. engbaekii and remaining isolates were not sequenced. Birds positive for M. avium included White Pelican (n = 1) Black Hornbill (n = 1), Macaw (n = 2), Cockatoo (n = 2) and village chicken (n = 1).ConclusionIt is concluded that chickens and birds were infected with M. avium in selected areas of Peninsular Malaysia. Although, PCR is rapid, reliable and cost effective method for detection of M. avium in a subclinical stage, the culture of the avian feces should still be used as a reference test for the diagnosis of avian tuberculosis.

Prevalence and molecular epidemiology of Johne’s disease in Egyptian cattle

Johne’s disease is chronic enteric incurable disease in ruminant, is caused by Mycobacterium avium subsp. paratuberculosis (MAP). The data about incidence and economic importance of the disease in Egypt are scare. The present study investigated the prevalence of Johne`s disease among cattle in some localities in Egypt. The results revealed that the infection was significantly higher in older animals than young animals (P = <0.05). The prevalence of the disease was higher in Gharbia governorate (19.6%) in comparison with other studied area. To determine the efficiency of diagnostic tests, 138 fecal samples were examined by culture and real-time PCR, the result showed slight agreement between both tests for detection of MAP in feces. Sequence analysis of IS1311 gene for isolated MAP strain from Egypt revealed high identity (98%) with other MAP strains from Germany and Netherland. MAP belongs to a subspecies genetically different from Mycobacterium avium subsp. Hominissuis (MAH) and Mycobacterium avium subsp. avium (MAA), therefore these results are as would be expected. This study confirms the circulation of MAP among cattle in Egypt and highlights the need for more study on the disease in the Middle East.

Rapid Identification of Mycobacterium avium subsp. avium from MB/BacT Bottles Using PCR

The mycobacterial infections caused by strains of Mycobacterium avium complex (MAC) in animals and humans are still present. Mycobacterium avium subsp. avium (MAA) is the etiologic agent of avian tuberculosis, a chronic contagious disease described in a wide variety of domestic and wild bird species. The aim of this study was to evaluate the advantage of using the MB/BacT bottles in an automated system and PCR method for rapid identification of the etiologic agent of tuberculosis in hens. The culture samples isolates from hens in the MB/BacT automated system and PCR amplification of insertion element (IS1245, IS901) it was a faster and specific method.

PRESENCE OF MYCOBACTERIUM AVIUM SUBSP. PARATUBERCULOSIS IN ALPACAS (LAMA PACOS) INHABITING THE CHILEAN ALTIPLANO.

Mycobacterium avium subsp. paratuberculosis (MAP) is the etiologic agent of paratuberculosis. The organism causes disease in both domestically managed and wild ruminant species. South American camelids have a long, shared history with indigenous people in the Andes. Over the last few decades, increasing numbers of alpacas were exported to numerous countries outside South America. No paratuberculosis surveillance has been reported for these source herds. In this study, individual fecal samples from 85 adult alpacas were collected from six separate herds in the Chilean Altiplano. A ParaTB mycobacterial growth indicator tube (MGIT) liquid culture of each individual fecal sample, followed by real-time polymerase chain reaction (PCR) protocol was used for confirmation. DNA extracts from a subset of confirmed MAP isolates were subjected to mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) typing. Fifteen alpaca were fecal culture test-positive. Five false-positive culture samples were negative on PCR analysis for Mycobacterium avium subsp. avium (MAA), Mycobacterium bovis (M. bovis), and the 16 S rDNA gene. Three MAP isolates subset-tested belonged to the same MIRU-VNTR type, showing four repeats for TR292 (locus 1) in contrast to the three repeats typical of the MAP reference strain K10. The number of repeats found in the remaining loci was identical to that of the K10 strain. It is not known how nor when MAP was introduced into the alpaca population in the Chilean Altiplano. The most plausible hypothesis to explain the presence of MAP in these indigenous populations is transmission by contact with infected domestic small ruminant species that may on occasion share pastures or range with alpacas. Isolation of this mycobacterial pathogen from such a remote region suggests that MAP has found its way beyond the confines of intensively managed domestic agriculture premises.

Avian tuberculosis in flocks of pigeons and its potential impact on tuberculination of cattle

Aims and objectivesThe Mycobacterium avium subsp avium (MAA) is a slow-growing, frequently-encountered mycobacterium in the environment that causes tuberculosis mainly in birds and sometimes in farm animals. As a favorite pet bird, the pigeon is extensively kept for homing and/or racing purposes in Iran, therefore, the main objective of this study was to investigate dissemination of M. avium subsp avium (MAA) in pigeon aviaries in Tabriz, North-western Iran. MethodsFrom a total of 140 birds collected from private flocks (n=3), The pathologically changed lungs and the lymph node were examined histologically by staining with Ziehl–Neelsen (Z–N) and hematoxylin–eosin; 39 were subjected to bacterial culture, out of which 34 mycobacterial isolates were recovered. Mycobacterial DNA was isolated according to the previously described method (Van Soolingen et al., 1993). Applying a five-PCR diagnostic algorithm targeting short, but definitive stretches of 16S rRNA and RV0577 genes, IS6110, IS901 and IS1245 genomic loci, all the isolates were identified as MAA. PvuII-IS901 RFLP typing was also performed on all isolates. ResultsThey were either IS901+/IS1245+ (n=22) or IS901+/IS1245 (n=12). In IS901-RFLP strain typing of a subset of the isolates (n=22), they were classified into five distinct multi-banded but similar patterns, namely PA (n=13), PB (n=5), PC (n=2), PD (n=1) and PE (n=1). No correlation between IS901-RFLP genotype and presence/lack of IS1245 was noted as isolates both holding and lacking IS1245 were found to share PA and PB genotypes. Whilst no case of mixed infection with more than one strain was detected in any single bird, it was not possible to extend this observation to the aviary level as original colonies of birds were not recorded. When four healthy cattle sensitized against Mycobacterium bovis AN5 and M. avium D4 were tuberculinated, the results confirmed the observed skin reactions against bovine tuberculin in animals sensitized with M. avium were large enough to complicate test interpretation. ConclusionsIt is believed that the extent of such epidemiological impact deserves further investigation if progress in the control of bovine tuberculosis is intended. This indicates the importance of identification of the causative agent before any conclusions are made, based solely upon the results of the skin test and histopathological examination.

Mannosylated Lipoarabinomannans from Mycobacterium Avium Subsp. Paratuberculosis Alters the Inflammatory Response by Bovine Macrophages and Suppresses Killing of Mycobacterium Avium Subsp. Avium Organisms

Analysis of the mechanisms through which pathogenic mycobacteria interfere with macrophage activation and phagosome maturation have shown that engagement of specific membrane receptors with bacterial ligands is the initiating event. Mannosylated lipoarabinomannan (Man-LAM) has been identified as one of the ligands that modulates macrophage function. We evaluated the effects of Man-LAM derived from Mycobacterium avium subsp. paratuberculosis (MAP) on bovine macrophages. Man-LAM induced a rapid and prolonged expression of IL-10 message as well as transient expression of TNF-α. Preincubation with Man-LAM for up to 16 h did not suppress expression of IL-12 in response to interferon-γ. Evaluation of the effect of Man-LAM on phagosome acidification, phagosome maturation, and killing of Mycobacterium avium subsp. avium (MAA) showed that preincubation of macrophages with Man-LAM before addition of MAA inhibited phagosome acidification, phagolysosome fusion, and reduced killing. Analysis of signaling pathways provided indirect evidence that inhibition of killing was associated with activation of the MAPK-p38 signaling pathway but not the pathway involved in regulation of expression of IL-10. These results support the hypothesis that MAP Man-LAM is one of the virulence factors facilitating survival of MAP in macrophages.

Serum protein profiles in domestic pigeons naturally infected with Mycobacterium avium subsp. avium

Avian tuberculosis is an important disease affecting all species of birds and is most often caused by Mycobacterium avium or Mycobacterium genavense. Blood proteins are important diagnostic constituents in gastrointestinal, hepatic, renal, and infectious diseases. The aim of the study was to compare serum protein profiles of domestic pigeons (Columba livia var. domestica) infected with Mycobacterium avium subsp. avium (MAA), with healthy pigeons. Serum samples were collected from 80 pigeons with clinical signs of tuberculosis, all kept in the same loft. All birds were necropsied and cultured for mycobacteriosis; positive cultures were typed for MAA by PCR reactions targeting 16S rRNA, IS901 and IS1245. The concentration of total serum proteins was determined by the biuret method and spectrophotometry. Individual protein fractions were analyzed by cellulose acetate electrophoresis and extrapolated based on total protein concentration. For statistical analysis, the infected birds were compared with healthy pigeons. A total of 37 pigeons with culture results positive for MAA were selected and allocated to 2 groups, a culture-positive group with macroscopic lesions of tuberculosis and another without macroscopic lesions. Six protein fractions were identified: prealbumin, albumin, alpha-1, alpha-2, and beta globulins and gamma globulins. Concentrations of total protein, beta globulins and gamma globulins were statistically significantly higher in the infected pigeons when compared with the control group. There were no significant differences between the groups of birds with or without macroscopic lesions. Statistically significant differences in total protein, and beta and gamma globulin concentrations in all infected pigeons suggest that serum protein electrophoresis represents a nonspecific but valuable indicator for tuberculosis in pigeons.

Genetic IS901RFLP diversity amongMycobacterium aviumsubsp.aviumisolates from four pheasant flocks

IS901 RFLP analysis of 36 Mycobacterium avium subsp. avium (MAA) isolates from 15 pheasants (Phasianus colchicus) and two goshawks (Accipiter gentilis) from four pheasant farms was performed. Using this method, six different IS901 RFLP types (E, F, G, M, Q, and V) were identified. The distribution of IS901 RFLP profiles was tightly linked to individual flocks. Matching IS901 RFLP profiles observed in the present study indicate MAA transmission between pheasants and goshawks in the same locality. In two flocks, different pheasants within a flock as well as in various organs of five individual pheasants were found to have two distinct IS901 RFLP profiles.

Different immune response of pigs to Mycobacterium avium subsp. avium and Mycobacterium avium subsp. hominissuis infection

Mycobacterium avium subsp. avium (MAA) and Mycobacterium avium subsp. hominissuis (MAH) are the most common mycobacterial species isolated from granulomatous lesions in swine in countries with controlled bovine tuberculosis. This study is focused on the immunological aspect of MAA and MAH infection in pigs. We detected induction of humoral and cell-mediated immunity in experimentally infected pigs. Specific antibodies were analyzed in serum by ELISA and the IFN-γ release assay was used for evaluation of cell-mediated immunity. While MAA induced a significant increase of both types of immune responses, MAH-infected pigs had an unvarying level of specific antibodies and showed low cell-mediated immunity with high individual variability. The subsequent in vitro experiment confirmed the lower immunogenicity of the MAH strain in comparison to MAA. MAH-infected porcine monocyte-derived macrophages showed a weaker induction of pro-inflammatory mediators in comparison to MAA, which included mRNA for IL-1β, TNF-α, IL-23p19, IL-18 and chemokines CCL-3, CCL-5, CXCL-8 and CXCL-10. Additionally, qualitative proteomic analysis revealed 28 proteins exclusively in MAA and 7 proteins unique to MAH. In conclusion, closely related M. avium subspecies MAA and MAH showed different capacities to stimulate the porcine immune system. From a diagnostic point of view, the IFN-γ release assay showed higher sensitivity than the detection of specific antibodies by ELISA and seems to be an effective tool for discrimination of MAA-infected pigs. In the case of MAH infection, the IFN-γ release assay could fail because of the low immunogenic capacity of the MAH strain.

Cell-mediated immune response in swine infected with Mycobacterium avium subsp. avium

The zoonotic characteristic of Mycobacterium avium subsp. avium ( MAA) represents a veterinary and economic problem in infected pigs. In this study, we analysed cell-mediated immunity six months after experimental infection by measuring interferon-γ (IFN-γ) production and by performing lymphocyte transformation tests after in vitro re-stimulation with the MAA-derived antigen. At the same time, IFN-γ-producing cells were characterised by flow cytometry. In MAA-infected animals, the production of IFN-γ increased in response to the MAA antigen in the blood, spleen and mesenteric lymph nodes. Similarly, a positive antigen-driven response was detected by the proliferation assay. In contrast, IFN-γ production and proliferation was undetectable after stimulation with the MAA antigen in uninfected control animals. These results indicate that both methods can be used for the identification of individual MAA-infected pigs. Using flow cytometry, we found that double-positive CD4 +CD8 + lymphocytes were the major T lymphocyte subset producing IFN-γ after in vitro re-stimulation.

Examination of Mycobacterium avium subsp. avium distribution in naturally infected hens by culture and triplex quantitative real time PCR

Mycobacterium avium subsp. avium (MAA) is the etiologic agent of avian tuberculosis, a chronic contagious disease described in a wide variety of domestic and wild bird species. The aims of this study were to assess the advantages of triplex quantitative real time PCR (qPCR) in comparison with culture testing for distribution of MAA in the organs of hens displaying varying degrees of clinical symptoms of the disease. From one small flock of ten hens and one cock with a history of weight loss, 98 tissue samples were examined in total. Pathological lesions were observed in six hens from which two were clinically ill. A total of 12 samples were positive by culture and 16 were positive by IS901 and IS1245 qPCR, confirming MAA infection. In conclusion, qPCR was a faster and more reliable alternative method in comparison with conventional culture analysis. Due to the detection of MAA in the muscle tissue of one hen, consumption of under cooked meat originating from infected fowl could pose a threat to immunosuppressed individuals.

Distribution of Mycobacterium avium subsp. avium and M. a. hominissuis in artificially infected pigs studied by culture and IS 901 and IS 1245 quantitative real time PCR

Mycobacterium avium subsp. avium ( MAA) and M. a. hominissuis ( MAH) belong to the Mycobacterium avium complex ( MAC) and are frequently associated with diseases in animals and humans. The aim of this study was to develop a system for rapid and accurate real time quantitative PCR (qPCR) identification and quantification of MAA and MAH. This study included 22 per os infected pigs, of which 10 were infected with MAA, 10 with MAH and 2 were present as a negative control group. From each animal, 21 different tissue samples as well as blood were tested by microscopy, culture and triplex qPCR. The developed triplex qPCR reaction was based on the simultaneous detection of specific insertion sequences, IS 901 and IS 1245, and also contained an internal amplification control. In both groups of experimentally infected animals, the newly developed triplex qPCR assay proved to be more specific and sensitive in comparison with the other methods used. Contrary to culture examination, triplex qPCR confirmed the infection in all animals infected with MAA, and in eight animals infected with MAH. In conclusion, we developed a quick and sufficiently sensitive triplex qPCR for MAA and MAH detection in tissue and blood samples. From the food safety point of view the presence of MAH in muscles should be considered as a possible threat to human health.

Experimental infection of Eurasian wild boar with Mycobacterium avium subsp. avium

The Eurasian wild boar ( Sus scrofa) is increasingly relevant as a host for several pathogenic mycobacteria. We aimed to characterize the first experimental Mycobacterium avium subsp. avium (MAA) infection in wild boar in order to describe the lesions and the immune response as compared to uninfected controls. Twelve 1–4-month-old wild boar piglets were housed in class III bio-containment facilities. Four concentrations of MAA suspension were used: 10, 10 2 and 10 4 mycobacteria (2 animals each, oropharyngeal route) and 2.5 × 10 6 mycobacteria (2 animals each by the oropharyngeal and nasal routes). No clinical signs were observed and pathology evidenced a low pathogenicity of this MAA strain for this particular host. Bacteriological and pathological evidence of successful infection after experimental inoculation was found for the group challenged with 2.5 × 10 6 mycobacteria. These four wild boar showed a positive IFN-γ response to the avian PPD and the real-time RT-PCR data revealed that three genes, complement component C3, IFN-γ and RANTES, were significantly down regulated in infected animals. These results were similar to those found in naturally and experimentally M. bovis-infected wild boar and may constitute biomarkers of mycobacterial infection in this species.

Mycobacterium avium subsp. avium distribution studied in a naturally infected hen flock and in the environment by culture, serotyping and IS 901 RFLP methods

Mycobacterium avium subsp. avium ( MAA) of serotype 2 and genotype IS 901+ and IS 1245+ was cultured from 21 naturally infected hens ( Gallus domesticus) from one smallholder aviary. From a total of 330 samples taken from hens, 124 mycobacteria were detected. Out of which MAA was detected in 103 (35.7%) of 288 tissues, in 4 (19.0%) of 21 swabs of cloacae and in 9 (42.9%) of 21 faeces samples, 8 other conditionally pathogenic mycobacterial species were also isolated. Tuberculous (TB) lesions were found in the liver, spleen and intestinal organs of seven hens. The isolates of MAA ( n = 58) from 16 infected hens (7 with TB lesions and 9 without TB lesions) were found to be of 3 IS 901 RFLP types AE ( n = 48), AD ( n = 4) and E ( n = 6), where these MAA isolates are highly virulent to hens. Mixed infections with IS 901 RFLP types (AE and AD) and (AE and E) were also evident in seven hens. From a total of 35 examined environmental samples, 23 mycobacterial isolates were detected. Out of which four (17.4%) MAA isolates of IS 901 RFLP type AE and 19 (82.6%) other isolates of conditionally pathogenic mycobacteria were detected. The finding of identical IS 901 RFLP types from both tissues and faecal isolates confirms that infected domestic hens are the principal source of infection for other susceptible hosts and lead to the contamination of the surrounding environment. The presence of different IS 901 RFLP types in tissue isolates may indicate the repeated incidence of MAA infection and the occurrence of polyclonal infection.

Granulomatous lesions in lymph nodes of slaughter pigs bacteriologically negative for Mycobacterium avium subsp. avium and positive for Rhodococcus equi

The prevalence of granulomatous lesions in lymph nodes of pigs was studied. From January till August 2004 in two slaughterhouses in The Netherlands 2,116,536 pigs were examined for the presence of granulomatous lesions in the sub-maxillary lymph nodes. In 15,900 (0.75%) of these pigs, lesions could be detected. Nine farms with the highest incidence of lesions were selected for a more detailed pathological and bacteriological examination. On these farms, the prevalence of lesions in sub-maxillary lymph nodes ranged from 2.3 to 5.7% with a mean of 3.0%. From 1276 pigs that were sampled, 98 (7.7%) displayed granulomatous lesions in the sub-maxillary lymph nodes and one (0.1%) pig showed lesions in its mesenteric lymph node. Mycobacterium avium subsp. avium (MAA) could not be isolated from the lymph nodes of the 99 pigs with lesions and from a selection of lymph nodes ( n = 61) of pigs without lesions. Rhodococcus equi was isolated from 44 out of 98 (44.9%) of the sub-maxillary lymph nodes with granulomatous lesions and from two mesenteric lymph nodes without lesions. A comparison of former studies and the current results indicate that the prevalence of MAA infections in slaughter pigs has strongly decreased over the last decade, whereas R. equi is highly prevalent. The high incidence of granulomatous lesions associated with the bacteriological presence of R. equi could be considered as a serious cause of misdiagnosis of MAA infections in cases where meat inspection is carried out by inspection for granulomatous changes of lymph nodes only.

MYCOBACTERIUM AVIUM SUBSPECIES PARATUBERCULOSIS AND MYCOBACTERIUM AVIUM SUBSP. AVIUM INFECTIONS IN A TULE ELK (CERVUS ELAPHUS NANNODES) HERD

Between 2 August and 22 September 2000, 37 hunter-killed tule elk (Cervus elaphus nannodes) were evaluated at the Grizzly Island Wildlife Area, California, USA, for evidence of paratuberculosis. Elk were examined post-mortem, and tissue and fecal samples were submitted for radiometric mycobacterial culture. Acid-fast isolates were identified by a multiplex polymerase chain reaction (PCR) that discriminates among members of the Mycobacterium avium complex (MAC). Histopathologic evaluations were completed, and animals were tested for antibodies using a Johne's enzyme-linked immunosorbent assay (ELISA) and agar gel immunodiffusion. In addition, 104 fecal samples from tule elk remaining in the herd were collected from the ground and submitted for radiometric mycobacterial culture. No gross lesions were detected in any of the hunter-killed animals. Mycobacterium avium subsp. paratuberculosis (MAP) was cultured once from ileocecal tissue of one adult elk and was determined to be a strain (A18) found commonly in infected cattle. One or more isolates of Mycobacterium avium subsp. avium (MAA) were isolated from tissues of five additional adult elk. Gastrointestinal tract and lymph node tissues from 17 of the 37 elk (46%) examined had histopathologic lesions commonly seen with mycobacterial infection; however, acid-fast bacteria were not observed. All MAC infections were detected from adult elk (P = 0.023). In adult elk, a statistically significant association was found between MAA infection and ELISA sample-to-positive ratio (S/P) > or = 0.25 (P=0.021); four of five MAA culture-positive elk tested positive by ELISA. Sensitivity and specificity of ELISA S/P > or = 0.25 for detection of MAA in adult elk were 50% and 93%, respectively. No significant associations were found between MAC infection and sex or histopathologic lesions. Bacteriologic culture confirmed infection with MAP and MAA in this asymptomatic tule elk herd. The Johne's ELISA was useful in signaling mycobacterial infection on a population basis but could not discriminate between MAA and MAP antibodies. The multiplex PCR was useful in discriminating among the closely related species belonging to MAC.

Annotating the Mycobacterium avium Genome: A Project in Bioinformatics

Bioinformatic tools facilitate efficient processing and formatting of experimental data and are becoming essential to research in the biological sciences. Whole genome sequencing projects, combined with DNA microarray technology, have allowed genomic comparisons between and within species of microorganisms. The genome of Mycobacterium avium subsp. avium (MAA) has been sequenced by The Institute for Genomic Research (TIGR), but a final and annotated version has not yet been made available. The goal of this project was to annotate the sequence of MAA as a foundation for microarray-based genomic comparisons. We used software to identify and predict open reading frames (ORFs) present in this organism. The ORFs were then compared to those catalogued in two large, online genetic databases for other microorganisms and matched to homologous sequences, allowing the determination of putative functions for each predicted gene. The genome of MAA was determined to contain 4480 genes, the majority of which are homologous to genes found in other Mycobacterial species.

Use of Bioinformatics to Predict a Function for the GS Element in Mycobacterium avium Subspecies paratuberculosis

Mycobacterium avium subsp. paratuberculosis (MAP) is a member of the Mycobacterium avium complex (MAC) and causes the inflammatory bowel disease, Johne’s disease, in livestock. MAP has also been implicated as the causative agent of a similar disease, Crohn’s disease, in humans. One of three major genetic differences between MAP and non-pathogenic MAC is the 6,496-bp GS element. Based on the output from freely available protein sequence and structural bioinformatics tools, and the close homology of GS genes with the ser2 region of the closely related Mycobacterium avium subsp. avium (MAA), we predict that GS encoded enzymes are involved in the biosynthesis of GDP-fucose, and the addition to, and modification of fucose on, the oligosaccharide moiety of GPL. GPL is a major constituent of the cell wall of the MAC and has immunomodulatory properties. Therefore, the enzymes involved in its synthesis may provide novel drug targets against MAP and other pathogenic MAC members.