Milk Contamination by Mycobacterium tuberculosis Complex, Implications for Public Health in Amazonas, Brazil.

ABSTRACT: In Brazil, contamination of raw milk with Mycobacterium tuberculosis complex (MTC) has been reported in several states. The highest rate of consumption of raw milk and its derivatives in Brazil occurs in Amazonas. This state also has the highest prevalence of tuberculosis in both humans and livestock. We assessed the contamination of cow's milk and buffalo's milk with MTC in Amazonas, focusing on Mycobacterium bovis, the species most commonly found in cattle and buffalo. In 2019, 250 samples of raw milk (91 from cattle, 159 from buffalo) were collected before processing from three milk plants in the state of Amazonas. The samples were placed into 21 pools and analyzed using shotgun metagenomic sequencing and taxonomic classification with Kraken 2 and MegaBLAST. To confirm the identity of mycobacterial species found, BLASTN was used to identify specific genomic positions in the TbD1 and RD1 regions and flanking RD4 region. MTC genetic material was identified in all pools of raw milk. Genetic material consistent with M. bovis was identified in seven pools of raw milk (1 from cattle, 6 from buffalo). Buffalo's milk had significantly higher MTC reads than did cow's milk. The common practice of consumption of raw milk and its derivatives in Amazonas presents a risk to public health. Urgent measures to prevent transmission of foodborne tuberculosis are needed in the Amazon region. Greater efforts and resources also should be directed toward elimination of bovine tuberculosis in cattle and buffalo herds in Amazonas and the rest of Brazil.

Ecological Assembly Processes Are Coordinated between Bacterial and Viral Communities in Fractured Shale Ecosystems.

The ecological drivers that concurrently act upon both a virus and its host and that drive community assembly are poorly understood despite known interactions between viral populations and their microbial hosts. Hydraulically fractured shale environments provide access to a closed ecosystem in the deep subsurface where constrained microbial and viral community assembly processes can be examined. Here, we used metagenomic analyses of time-resolved-produced fluid samples from two wells in the Appalachian Basin to track viral and host dynamics and to investigate community assembly processes. Hypersaline conditions within these ecosystems should drive microbial community structure to a similar configuration through time in response to common osmotic stress. However, viral predation appears to counterbalance this potentially strong homogeneous selection and pushes the microbial community toward undominated assembly. In comparison, while the viral community was also influenced by substantial undominated processes, it assembled, in part, due to homogeneous selection. When the overall assembly processes acting upon both these communities were directly compared with each other, a significant relationship was revealed, suggesting an association between microbial and viral community development despite differing selective pressures. These results reveal a potentially important balance of ecological dynamics that must be in maintained within this deep subsurface ecosystem in order for the microbial community to persist over extended time periods. More broadly, this relationship begins to provide knowledge underlying metacommunity development across trophic levels.IMPORTANCE Interactions between viral communities and their microbial hosts have been the subject of many recent studies in a wide range of ecosystems. The degree of coordination between ecological assembly processes influencing viral and microbial communities, however, has been explored to a much lesser degree. By using a combined null modeling approach, this study investigated the ecological assembly processes influencing both viral and microbial community structure within hydraulically fractured shale environments. Among other results, significant relationships between the structuring processes affecting both the viral and microbial community were observed, indicating that ecological assembly might be coordinated between these communities despite differing selective pressures. Within this deep subsurface ecosystem, these results reveal a potentially important balance of ecological dynamics that must be maintained to enable long-term microbial community persistence. More broadly, this relationship begins to provide insight into the development of communities across trophic levels.

Non-canonical cyclic AMP SMAD1/5/8 signalling in human granulosa cells.

Development of mammalian ovarian follicles is promoted by the combined action of endocrine cues and paracrine factors. Follicle stimulating hormone (FSH), through the action of cAMP drives follicular growth and development. The oocyte secretes powerful growth factors such as bone morphogenetic protein 15 (BMP15) to regulate granulosa cell proliferation, metabolism, steroidogenesis and differentiation through the activation of SMAD1/5/8. This study investigated the role of the cAMP signalling pathway on SMAD1/5/8 action in human granulosa cells. Cyclic AMP enhanced BMP15-induction of a SMAD1/5/8-specific BRE reporter. Moreover, in the absence of BMP ligand, cAMP also activated SMAD1/5/8-induced BRE activity. Cyclic AMP increased canonical downstream targets of BMP signalling such as inhibitor of differentiation (ID) mRNA expression. The observed effects were not mediated by secretion of BMPs as cAMP did not promote BMP ligand mRNA expression and a BMP extracellular antagonist, the BMP type II receptor ectodomain, did not affect cAMP-induced ID mRNA expression. Finally, the ERK1/2 pathway was shown to be required for the maintenance of cAMP-induced SMAD1/5/8 activity. Together our results suggest a novel and non-canonical pathway for cAMP signalling in human granulosa cells. Cyclic AMP appears to promote SMAD1/5/8 pathway activity intracellularly and has the ability to activate canonical SMAD1/5/8 downstream targets. Our results add another layer of complexity to the interactions between endocrine signalling and oocyte-secreted BMP ligands during folliculogenesis. Given the importance of both cAMP and SMAD1/5/8 pathways in follicular development, these interactions are likely required for the fine-tuning of oocyte paracrine signalling by endocrine stimuli.

Members of the Candidate Phyla Radiation are functionally differentiated by carbon- and nitrogen-cycling capabilities.

BACKGROUND: The Candidate Phyla Radiation (CPR) is a recently described expansion of the tree of life that represents more than 15% of all bacterial diversity and potentially contains over 70 different phyla. Despite this broad phylogenetic variation, these microorganisms appear to feature little functional diversity, with members generally characterized as obligate fermenters. Additionally, much of the data describing CPR phyla has been generated from a limited number of environments, constraining our knowledge of their functional roles and biogeographical distribution. To expand our understanding of subsurface CPR microorganisms, we sampled four separate groundwater wells over 2 years across three Ohio counties. RESULTS: Samples were analyzed using 16S rRNA gene amplicon and shotgun metagenomic sequencing. Amplicon results indicated that CPR members comprised between 2 and 20% of the microbial communities with relative abundances stable through time in Athens and Greene samples but dynamic in Licking groundwater. Shotgun metagenomic analyses generated 71 putative CPR genomes, representing roughly 32 known phyla and 2 putative new phyla, Candidatus Brownbacteria and Candidatus Hugbacteria. While these genomes largely mirrored metabolic characteristics of known CPR members, some features were previously uncharacterized. For instance, nitrite reductase, encoded by nirK, was found in four of our Parcubacteria genomes and multiple CPR genomes from other studies, indicating a potentially undescribed role for these microorganisms in denitrification. Additionally, glycoside hydrolase (GH) family profiles for our 71 genomes and over 2000 other CPR genomes were analyzed to characterize their carbon-processing potential. Although common trends were present throughout the radiation, differences highlighted potential mechanisms that could allow microorganisms across the CPR to occupy various subsurface niches. For example, members of the Microgenomates superphylum appear to potentially degrade a wider range of carbon substrates than other CPR phyla. CONCLUSIONS: CPR members are present across a range of environments and often constitute a significant fraction of the microbial population in groundwater systems, particularly. Further sampling of such environments will resolve this portion of the tree of life at finer taxonomic levels, which is essential to solidify functional differences between members that populate this phylogenetically broad region of the tree of life.

Pulmonary arterial hypertension - progress in understanding the disease and prioritizing strategies for drug development.

Pulmonary arterial hypertension (PAH), at one time a largely overlooked disease, is now the subject of intense study in many academic and biotech groups. The availability of new treatments has increased awareness of the condition. This in turn has driven a change in the demographics of PAH, with an increase in the mean age at diagnosis. The diagnosis of PAH in more elderly patients has highlighted the need for careful phenotyping of patients and for further studies to understand how best to manage pulmonary hypertension associated with, for example, left heart disease. The breadth and depth of expertise focused on unravelling the molecular pathology of PAH has yielded novel insights, including the role of growth factors, inflammation and metabolic remodelling. The description of the genetic architecture of PAH is accelerating in parallel, with novel variants, such as those reported in potassium two-pore domain channel subfamily K member 3 (KCNK3), adding to the list of more established mutations in genes associated with bone morphogenetic protein receptor type 2 (BMPR2) signalling. These insights have supported a paradigm shift in treatment strategies away from simply addressing the imbalance of vasoactive mediators observed in PAH towards tackling more directly the structural remodelling of the pulmonary vasculature. Here, we summarize the changing clinical and molecular landscape of PAH. We highlight novel drug therapies that are in various stages of clinical development, targeting for example cell proliferation, metabolic, inflammatory/immune and BMPR2 dysfunction, and the challenges around developing these treatments. We argue that advances in the treatment of PAH will come through deep molecular phenotyping with the integration of clinical, genomic, transcriptomic, proteomic and metabolomic information in large populations of patients through international collaboration. This approach provides the best opportunity for identifying key signalling pathways, both as potential drug targets and as biomarkers for patient selection. The expectation is that together these will enable the prioritization of potential therapies in development and the evolution of personalized medicine for PAH.

Phenotypic differentiation is associated with divergent sexual selection among closely related barn swallow populations.

Sexual selection plays a key role in the diversification of numerous animal clades and may accelerate trait divergence during speciation. However, much of our understanding of this process comes from phylogenetic comparative studies, which rely on surrogate measures such as dimorphism that may not represent selection in wild populations. In this study, we assess sexual selection pressures for multiple male visual signals across four barn swallow (Hirundo rustica) populations. Our sample encompassed 2400 linear km and two described subspecies: European H. r. rustica (in the Czech Republic and Romania) and eastern Mediterranean H. r. transitiva (in Israel), as well as a potential area of contact (in Turkey). We demonstrate significant phenotypic differentiation in four sexual signalling axes, despite very low-level genomic divergence and no comparable divergence in an ecological trait. Moreover, the direction of phenotypic divergence is consistent with differences in sexual selection pressures among subspecies. Thus, H. r. transitiva, which have the darkest ventral plumage of any population, experience directional selection for darker plumage. Similarly, H. r. rustica, which have the longest tail feathers of any population, experience directional selection for elongated tail feathers and disruptive selection for ventral plumage saturation. These results suggest that sexual selection is the primary driver of phenotypic differentiation in this species. Our findings add to growing evidence of phenotypic divergence with gene flow. However, to our knowledge, this is the first study to relate direct measures of the strength and targets of sexual selection to phenotypic divergence among closely related wild populations.

Genome-wide differentiation in closely related populations: the roles of selection and geographic isolation.

Population divergence in geographic isolation is due to a combination of factors. Natural and sexual selection may be important in shaping patterns of population differentiation, a pattern referred to as 'isolation by adaptation' (IBA). IBA can be complementary to the well-known pattern of 'isolation by distance' (IBD), in which the divergence of closely related populations (via any evolutionary process) is associated with geographic isolation. The barn swallow Hirundo rustica complex comprises six closely related subspecies, where divergent sexual selection is associated with phenotypic differentiation among allopatric populations. To investigate the relative contributions of selection and geographic distance to genome-wide differentiation, we compared genotypic and phenotypic variation from 350 barn swallows sampled across eight populations (28 pairwise comparisons) from four different subspecies. We report a draft whole-genome sequence for H. rustica, to which we aligned a set of 9493 single nucleotide polymorphisms (SNPs). Using statistical approaches to control for spatial autocorrelation of phenotypic variables and geographic distance, we find that divergence in traits related to migratory behaviour and sexual signalling, as well as geographic distance, together explain over 70% of genome-wide divergence among populations. Controlling for IBD, we find 42% of genomewide divergence is attributable to IBA through pairwise differences in traits related to migratory behaviour and sexual signalling alone. By (i) combining these results with prior studies of how selection shapes morphological differentiation and (ii) accounting for spatial autocorrelation, we infer that morphological adaptation plays a large role in shaping population-level differentiation in this group of closely related populations.

Single TRAM domain RNA-binding proteins in Archaea: functional insight from Ctr3 from the Antarctic methanogen Methanococcoides burtonii.

TRAM domain proteins present in Archaea and Bacteria have a ß-barrel shape with anti-parallel ß-sheets that form a nucleic acid binding surface; a structure also present in cold shock proteins (Csps). Aside from protein structures, experimental data defining the function of TRAM domains is lacking. Here, we explore the possible functional properties of a single TRAM domain protein, Ctr3 (cold-responsive TRAM domain protein 3) from the Antarctic archaeon Methanococcoides burtonii that has increased abundance during low temperature growth. Ribonucleic acid (RNA) bound by Ctr3 in vitro was determined using RNA-seq. Ctr3-bound M. burtonii RNA with a preference for transfer (t)RNA and 5S ribosomal RNA, and a potential binding motif was identified. In tRNA, the motif represented the C loop; a region that is conserved in tRNA from all domains of life and appears to be solvent exposed, potentially providing access for Ctr3 to bind. Ctr3 and Csps are structurally similar and are both inferred to function in low temperature translation. The broad representation of single TRAM domain proteins within Archaea compared with their apparent absence in Bacteria, and scarcity of Csps in Archaea but prevalence in Bacteria, suggests they represent distinct evolutionary lineages of functionally equivalent RNA-binding proteins.

Solvent immersion imprint lithography.

We present Solvent Immersion Imprint Lithography (SIIL), a technique for polymer functionalization and microsystem prototyping. SIIL is based on polymer immersion in commonly available solvents. This was experimentally and computationally analyzed, uniquely enabling two practical aspects. The first is imprinting and bonding deep features that span the 1 to 100 µm range, which are unattainable with existing solvent-based methods. The second is a functionalization scheme characterized by a well-controlled, 3D distribution of chemical moieties. SIIL is validated by developing microfluidics with embedded 3D oxygen sensors and microbioreactors for quantitative metabolic studies of a thermophile anaerobe microbial culture. Polystyrene (PS) was employed in the aforementioned applications; however all soluble polymers - including inorganic ones - can be employed with SIIL under no instrumentation requirements and typical processing times of less than two minutes.

Survival of HIV-positive individuals with hepatitis B and C infection in Michigan.

We sought to estimate mortality and associated factors in HIV-hepatitis co-infected individuals in Michigan using a retrospective cohort study. For the study period of 1 January 2006 to 31 December 2009, all HIV-infected individuals were matched to hepatitis B and C cases. In the final Cox proportional hazards regression model, individuals of other [hazard ratio (HR) 2·2, 95% confidence interval (CI) 1·4-3·2] and black (HR 1·3, 95% CI 1·1-1·6) race had decreased survival compared to white race. Similarly, injecting drug users (IDUs) (HR 2·1, 95% CI 1·6-2·6), men who have sex with men (MSM)/IDUs (HR 1·5, 95% CI 1·1-2·2), individuals with undetermined risk (HR 1·5, 95% CI 1·2-1·9) and heterosexual practices (HR 1·4, 95% CI 1·1-1·8) had decreased survival compared to MSM. Additionally, an interaction was found between current HIV status and co-infection. Mortality in HIV-hepatitis co-infected individuals remains a continuing problem. Our study can help in planning interventions to reduce mortality in HIV-infected individuals.

Hepatitis B and C co-infection in HIV/AIDS population in the state of Michigan.

A retrospective cohort study was conducted from 1 January 2006 to 31 December 2009 in Michigan to estimate the prevalence of HIV and hepatitis co-infection and identify associated factors. The prevalence of co-infection was 4.1% [95% confidence interval (CI) 3.8-4.5]. Multivariable logistic regression analysis revealed a significant association between co-infection and being male and: of Black race [odds ratio (OR) 2.0, 95% CI 1.2-3.6] and of Other race (OR 3.5, 95% CI 1.7-7.0) compared to Hispanic race. A significant association was found between co-infection and risk categories of blood products (OR 11.1, 95% CI 6.2-20.2), injecting drug user (IDU) (OR 3.6, 95% CI 2.7-4.8) and men who have sex with men/IDU (OR 3.4, 95% CI 2.4-4.9) in addition to two interactions; one between sex and current HIV status and the other between current HIV status and age at HIV diagnosis. Our results document the changing epidemiology of HIV-hepatitis co-infection which can guide preventive measures and interventions to reduce the prevalence of hepatitis co-infection.

The role of mesenchymal stem cells in veterinary therapeutics - a review.

Adult mammalian tissue contains a population of cells known as mesenchymal stem cells (MSC), that possess the capability to secrete regenerative cytokines and to differentiate into specialised cell types. When transplanted to a site of injury MSC embed in damaged tissue and repair and regenerate the tissue by secreting cytokines. The immuno-privileged and immuno-regulatory capabilities of MSC enhance their therapeutic potential not only in autologous but also allogeneic recipients. Studies have demonstrated the beneficial effects of MSC in the treatment of a variety of clinical conditions including osteoarthritis, tendon injuries, and atopic dermatitis in domestic animals. Studies using animal models have shown promising results following MSC or MSC secretion therapy for induced injury in musculoskeletal and nervous systems and some organ diseases. This review describes the stem cell types relevant to regenerative medicine and the procedures used for isolation, identification, expansion, enrichment and differentiation of these cells. We also review the use of MSC in animal models of disease as well as diseases in the clinical veterinary setting.

Pulmonary hypertension: the science behind the disease spectrum.

Pulmonary hypertension (PH) is a complex, multifactorial disorder divided into five major subtypes according to pathological, pathophysiological and therapeutic characteristics. Although there are distinct differences between the PH categories, a number of processes are common to the pathology of all subtypes. Vasoconstriction, as a result of endothelial dysfunction and an imbalance in the levels of vasoactive mediators, is a well-characterised contributory mechanism. Excessive cell proliferation and impaired apoptosis in pulmonary vessels leading to structural remodelling is most evident in pulmonary arterial hypertension (PAH), and several factors have been implicated, including mitochondrial dysfunction and mutations in bone morphogenetic protein receptor type 2. Inflammation plays a key role in the development of PH, with increased levels of many cytokines and chemokines in affected patients. Exciting insights into the role of angiogenesis and bone marrow-derived endothelial progenitor cells in disease progression have also recently been revealed. Furthermore, there is increasing interest in changes in the right ventricle in PH and the role of metabolic abnormalities. Despite considerable progress in our understanding of the molecular mechanisms of PH, further research is required to unravel and integrate the molecular changes into a better understanding of the pathophysiology of PH, particularly in non-PAH, to put us in a better position to use this knowledge for improved treatments.

Serological survey of Toxoplasma gondii and Campylobacter fetus fetus in sheep from New Zealand.

AIM: To determine the prevalence of antibody titres to Toxoplasma gondii and Campylobacter fetus fetus in sheep from New Zealand. METHODS: As part of a free screening service, unsolicited blood samples were supplied by veterinarians wishing to gauge the exposure of their clients' ewe flocks to T. gondii and C. fetus fetus. Blood samples were submitted from mixed-age ewes throughout New Zealand, from 2006 to 2009, that had not been vaccinated for T. gondii and C. fetus fetus. A total of 2,254 sera were serologically titrated for T. gondii and 3,429 for C. fetus fetus. A latex agglutination kit available commercially was used to quantify antibodies to T. gondii, and an agglutination test developed in-house was used for C. fetus fetus. For T. gondii, titres of ≥1:16 and ≥1:64 were used to define a positive response, and for C. fetus fetus a titre of ≥1:10 was defined as positive. A flock was defined as positive if ≥1 ewe had a positive titre. RESULTS: Of the sera tested for T. gondii, 1,917/2,254 (85%) were positive, using a titre of ≥1:16, and 1,384/2,254 (61%) with a titre of ≥1:64. All 198 ewe flocks tested were seropositive to T. gondii, at a titre of ≥1:16, and all but three were at a titre of ≥1:64. A bimodal distribution was evident in the prevalence of titres to T. gondii suggesting that a percentage of titres ≤1:64 may have been non-specific. Of the sera tested for C. fetus fetus, 1,644/3,429 (48%) were positive to at least one of the four test antigens at titre of ≥1:10. Only 34/298 (11%) flocks tested for C. fetus fetus were completely seronegative. The percentage of seropositive ewes to both T. gondii and C. fetus fetus was significantly higher in the North Island than the South Island. CONCLUSIONS: The study demonstrated that exposure to these two important infectious abortifacients was both considerable and widespread. Minimum titres were postulated to establish a 'cut-off' for a positive result and to allow comparison with past and future studies. The bimodal distribution evident for T. gondii suggested a titre of 1:64 may be an appropriate cut-off. The widespread on-farm exposure probably stimulates the immune response of vaccinated ewes. CLINICAL RELEVANCE: Further studies are required to confirm the clinical significance of flock-based antibody responses, and to validate their use in identifying recently aborted ewes, especially where there are no aborted fetuses for examination.

Iron deficiency in pulmonary arterial hypertension: a potential therapeutic target.

Iron deficiency is known to be common and detrimental in chronic left heart failure, where parenteral iron treatment has been shown to improve exercise capacity, New York Heart Association functional class and patient wellbeing. There is now increasing interest in the role of iron in the natural history of pulmonary arterial hypertension (PAH). Iron availability influences the pulmonary vasoconstrictor response to hypoxia and accumulating evidence indicates that iron deficiency is prevalent in idiopathic and heritable forms of PAH, iron status being related to exercise capacity, symptoms and poorer survival in patients with idiopathic PAH (IPAH). Potential mechanisms behind iron deficiency in IPAH include inhibition of dietary iron uptake by the master iron regulator hepcidin. High hepcidin levels underlie the anaemia of chronic disease. Possible stimuli of the observed high levels of hepcidin in IPAH include dysfunctional bone morphogenetic protein receptor type II signalling and inflammation. Iron status may influence outcomes through modulation of the pulmonary circulation as well as myocardial and skeletal muscle function. Two parallel studies, from our centre (Hammersmith Hospital, London, UK) and others in the UK and Amsterdam (the Netherlands), investigating the safety and potential benefit of iron supplementation in patients with PAH are currently under way.

Visual fields in patients with multifocal intraocular lens implants and monovision: an exploratory study.

PURPOSE: To assess the difference in binocular visual fields (VFs) in patients who underwent bilateral cataract surgery with either multifocal (MF; Tecnis ZM900, AMO) intraocular lenses (IOLs) or monofocal IOLs with powers adjusted to give monovision (MV; Akreos AO, Bausch&Lomb). SETTING: St George's & Moorfields Eye Hospital, London. METHODS: Prospective exploratory study. Binocular Esterman VFs (Humphrey Field Analyser II) were compared between 10 participants with MV and 16 participants with MF IOLs. The dominant eye in MV participants had 0 to -0.50DS and the non-dominant eye had between -1.0DS and -1.5DS. Best-corrected Snellen visual acuity for all 52 eyes was six out of nine or better. The main outcome measure was Esterman Efficiency Score. Incidence of suboptimal VF results (≥1 Unseen Locations--ULs) and mean testing times in the two groups were compared. RESULTS: There was no statistically significant difference in the incidence of suboptimal VF results in these two groups (P=0.662). Test durations in the two groups were not significantly different (P=0.650). However, 3/10 MV plots (33%) had markedly suboptimal right hemi-fields (distance-dominant eye) compared with 0/15 MF plots. Additionally, the MV group accounted for 79% of total ULs (20/29) and all these ULs were distributed in areas outside or bordering the true binocular VFs. CONCLUSIONS: All included VFs met the UK driving standards criteria. The pattern of VF defects encountered in the MV group is of interest because the majority of ULs (13/20; 65%) corresponded to the monocular VFs of the distance-dominant eye.

Tetrahydrobiopterin and the regulation of hypoxic pulmonary vasoconstriction.

Tetrahydrobiopterin (BH(4)) is an essential cofactor for nitric oxide synthases (NOS). This study investigated the effect of increasing BH(4) levels on hypoxia-induced pulmonary vasoconstriction (HPV). Sprague Dawley rats and hph-1 (BH(4) deficient) mice were given BH(4) before and during HPV in an isolated perfused lung preparation. BH(4) inhibited HPV in a concentration-dependent manner and increased NO metabolites in the perfusate. Bradykinin-induced reductions in HPV were blunted in hph-1 mice and pre-administration of BH(4) restored the response. The effect of BH(4) was attenuated by l-NAME (NOS inhibitor), PTIO (NO scavenger), and catalase (H(2)O(2) catalyser) administered prior to HPV but enhanced by MnTMPyP (superoxide dismutase mimetic). The effect of BH(4) on HPV was partially recapitulated by NH(4), a stereoisomer that shares antioxidant properties with BH(4) but is not a NOS cofactor. The bioavailability of BH(4) is an important determinant of the pulmonary vascular response to hypoxia. Its effects are mediated via nitric oxide, hydrogen peroxide and its antioxidant properties, and are attenuated by oxidant stress. Pharmacological administration of BH(4) may have therapeutic potential in pulmonary hypertension.

The role of exposures to animals and other risk factors in sporadic, non-typhoidal Salmonella infections in Michigan children.

Salmonellosis is largely a major foodborne disease. However, contact with animals particularly reptiles, has been increasingly recognized as a risk factor for Salmonella infection among children. The major risk factors for salmonellosis in Michigan children have not been assessed. Therefore, we have evaluated the association between Salmonella infections and contact with animals among Michigan children aged ≤ 10 years by conducting a population-based case-control study. A total of 123 children with laboratory-confirmed Salmonella infections and 139 control children, who had not experienced symptoms of gastrointestinal illness during the month prior to the interviews, were enrolled. A multivariable analysis matched on age group revealed that children with Salmonella infections had reported more commonly than controls contact with reptiles [adjusted matched odds ratio (MOR) = 7.90, 95% confidence interval (CI): 1.52-41.01] and cats (MOR = 2.53, 95% CI: 1.14-5.88). Results of this study suggest an association between salmonellosis and contact with cats and reptiles in Michigan children. Additional efforts are needed to educate caretakers of young children about the risk of Salmonella transmission through animal contact.

Use of multiple-locus variable number tandem repeat analysis and phage typing for subtyping of Salmonella Enteritidis from sporadic human cases in the United States.

AIMS: To investigate the genetic diversity among S. Enteritidis isolates from different geographic regions to evaluate the relationship between phage types (PTs) and variable number tandem repeat analysis (VNTR) loci. METHODS AND RESULTS: We performed multiple-locus variable number tandem repeat analysis (MLVA) and phage typing on 245 S. Enteritidis isolates collected from sporadic human clinical cases in Michigan, Minnesota, New York, and Washington states between 2000 and 2007. Ninety-four MLVA types and 22 different PTs were identified. Specific PTs were associated with a predominant allele for certain VNTR loci. Cluster analysis using a minimum-spanning tree demonstrated two major clusters (I, II) and one minor cluster of isolates. PTs 8, 13a, 13 and 34 were significantly associated with MLVA cluster I. Phage types 1, 4, 6a, and 18 were significantly associated with MLVA cluster II. CONCLUSIONS: We found significant association between MLVA-based clusters and PTs. Certain VNTR loci were associated with specific PTs and could serve as useful molecular markers for S. Enteritidis in epidemiological investigations. SIGNIFICANCE AND IMPACT OF THE STUDY: MLVA genotyping in combination with phage typing can be used for effective characterization of S. Enteritidis isolates. It can also be useful for tracing possible sources during investigations of sporadic and outbreak cases of S. Enteritidis.