RESUMEN
Ticks are obligatory hematophagous ectoparasites that transmit pathogens among various vertebrates, including humans. The microbial and viral communities of ticks, including pathogenic microorganisms, are known to be highly diverse. However, the factors driving this diversity are not well understood. The tropical horse tick, Dermacentor nitens, is distributed throughout the Americas and it is recognized as a natural vector of Babesia caballi and Theileria equi, the causal agents of equine piroplasmosis. In this study, we characterized the bacterial and viral communities associated with partially fed Dermacentor nitens females collected using a passive survey on horses from field sites representing three distinct geographical areas in the country of Colombia (Bolivar, Antioquia, and Cordoba). RNA-seq and sequencing of the V3 and V4 hypervariable regions of the 16S rRNA gene were performed using the Illumina-Miseq platform (Illumina, San Diego, CA, USA). A total of 356 operational taxonomic units (OTUs) were identified, in which the presumed endosymbiont, Francisellaceae/Francisella spp., was predominantly found. Nine contigs corresponding to six different viruses were identified in three viral families: Chuviridae, Rhabdoviridae, and Flaviviridae. Differences in the relative abundance of the microbial composition among the geographical regions were found to be independent of the presence of Francisella-like endosymbiont (FLE). The most prevalent bacteria found in each region were Corynebacterium in Bolivar, Staphylococcus in Antioquia, and Pseudomonas in Cordoba. Rickettsia-like endosymbionts, mainly recognized as the etiological agent of rickettsioses in Colombia, were detected in the Cordoba samples. Metatranscriptomics revealed 13 contigs containing FLE genes, suggesting a trend of regional differences. These findings suggest regional distinctions among the ticks and their bacterial compositions.
RESUMEN
Ticks are obligatory hematophagous ectoparasites that transmit pathogens among various vertebrates, including humans. The composition of the microbial and viral communities in addition to the pathogenic microorganisms is highly diverse in ticks, but the factors driving the diversity are not well understood. The tropical horse tick, Dermacentor nitens , is distributed throughout the Americas and it is recognized as a natural vector of Babesia caballi and Theileria equi , the causal agents of equine piroplasmosis. We characterized the bacterial and viral communities associated with partially-fed D. nitens females collected by a passive survey on horses from field sites representing three distinct geographical areas in Colombia (Bolivar, Antioquia, and Cordoba). RNA-seq and sequencing of the V3 and V4 hypervariable regions of the 16S rRNA gene were performed using the Illumina-Miseq platform. A total of 356 operational taxonomic units (OTUs) were identified, in which the presumed endosymbiotic Francisellaceae/ Francisella spp. was predominantly found. Nine contigs corresponding to six different viruses were identified in three viral families: Chuviridae, Rhabdoviridae, and Flaviviridae. Differences in the relative abundance of the microbial composition among the geographical regions were found to be independent of the presence of Francisella -Like Endosymbiont (FLE). The most prevalent bacteria found on each region were Corynebacterium in Bolivar, Staphylococcus in Antioquia, and Pseudomonas in Cordoba. Rickettsia -like endosymbionts, mainly recognized as the etiological agent of rickettsioses in Colombia were detected in the Cordoba samples. Metatranscriptomics revealed 13 contigs containing FLE genes, suggesting a trend of regional differences. These findings suggest regional distinctions among the ticks and their bacterial compositions.
RESUMEN
U.S. military troops are exposed to mosquito-borne pathogens when deployed to endemic regions. Personal protective measures such as permethrin-treated uniforms and dermal repellents are the cornerstones of mosquito-borne disease prevention for the U.S. military. These measures have limitations and additional personal protection tools, such as spatial repellent devices to decrease the risk of vector-borne pathogen transmission, are required. Novel spatial repellent controlled-release devices formulated with metofluthrin were evaluated in an outdoor setting in the northern Amazon of Peru to evaluate performance under field conditions. The metofluthrin emitting devices lowered the number of mosquitoes captured in protected human landing collections (HLC) compared to blank devices, although there were effect differences between Anopheles spp. and species in other mosquito genera. A computational-experimental model was developed to correlate HLC and active ingredient (AI) concentrations as a function of time and space. Results show a strong correlation between the released AI and the decrease in HLC. This model represents the first effort to obtain a predictive analytical tool on device performance using HLC as the entomological endpoint.
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BACKGROUND: In Peru, the information regarding sand fly vectors of leishmaniasis and bartonellosis in the Amazon region is limited. In this study, we carried out sand fly collections in Peruvian lowland and highland jungle areas using different trap type configurations and screened them for Leishmania and Bartonella DNA. METHODOLOGY/PRINCIPAL FINDINGS: Phlebotomine sand flies were collected in Peruvian Amazon jungle and inter Andean regions using CDC light trap, UV and color LED traps, Mosquito Magnet trap, BG Sentinel trap, and a Shannon trap placed outside the houses. Leishmania spp. screening was performed by kDNA PCR and confirmed by a nested cytochrome B gene (cytB) PCR. Bartonella spp. screening was performed by ITS PCR and confirmed by citrate synthase gene (gltA). The PCR amplicons were sequenced to identify Leishmania and Bartonella species. UV and Blue LED traps collected the highest average number of sand flies per hour in low jungle; UV, Mosquito Magnet and Shannon traps in high jungle; and Mosquito Magnet in inter Andean region. Leishmania guyanensis in Lutzomyia carrerai carrerai and L. naiffi in Lu. hirsuta hirsuta were identified based on cytB sequencing. Bartonella spp. related to Bartonella bacilliformis in Lu. whitmani, Lu. nevesi, Lu. hirsuta hirsuta and Lu. sherlocki, and a Bartonella sp. related to Candidatus B. rondoniensis in Lu. nevesi and Lu. maranonensis were identified based on gltA gene sequencing. CONCLUSIONS/SIGNIFICANCE: UV, Blue LED, Mosquito Magnet and Shannon traps were more efficient than the BG-Sentinel, Green, and Red LED traps. This is the first report of L. naiffi and of two genotypes of Bartonella spp. related to B. bacilliformis and Candidatus B. rondoniensis infecting sand fly species from the Amazon region in Peru.
Asunto(s)
Infecciones por Bartonella/transmisión , Bartonella bacilliformis/aislamiento & purificación , Control de Insectos/métodos , Insectos Vectores/fisiología , Leishmania/aislamiento & purificación , Leishmaniasis/transmisión , Phlebotomus/fisiología , Animales , Infecciones por Bartonella/microbiología , Bartonella bacilliformis/clasificación , Bartonella bacilliformis/genética , Humanos , Control de Insectos/instrumentación , Insectos Vectores/microbiología , Insectos Vectores/parasitología , Leishmania/clasificación , Leishmania/genética , Leishmaniasis/parasitología , Perú , Phlebotomus/microbiología , Phlebotomus/parasitologíaRESUMEN
Rickettsiae and bartonellae are Gram-negative bacteria that can cause zoonotic and human diseases and are vectored by hematophagous arthropods. In the Americas, rickettsioses and bartonelloses have reemerged as significant public health threats. Bartonella species have been identified as causing zoonotic infections responsible for a variety of clinical syndromes in humans and animals. The aim of this study was to investigate the distribution, prevalence, and molecular heterogeneity of Rickettsia spp. and Bartonella spp. among ectoparasites collected from domestic animals in 14 farming communities in the Andes Mountains of Cuzco, Peru. A total of 222 domestic animals representing 8 different species (sheep, donkeys, goats, cattle, pigs, llamas, guinea pigs, and horses) were sampled. Nine species of ectoparasites (n = 1,697) collected from 122 animals were identified resulting in 1,657 chewing lice, 39 ticks, and 1 flea. DNA was individually extracted from a random sample of 600 (35.4%) considering variability of ectoparasite species, hosts, and sample location elevation. All 600 samples were negative for rickettsial DNA by a genus-specific molecular assay. A subset of 173 (28.8%) samples were selected based on variability of arthropods species, host, and location for Bartonella testing. Ninety-one (52.6%) of these samples including Melophagus ovinus (90/110) and Bovicola bovis (1/7) were positive for Bartonella by a genus-specific molecular assay. Five Bartonella genes of seven DNA samples from M. ovinus were analyzed by the multilocus sequence typing for characterization. We identified five identical Bartonella melophagi specimens and two specimens with Bartonella species related to B. melophagi from the seven M. ovinus. The Bartonella agents detected were widely distributed and frequent in multiple studied locations.
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Infecciones por Bartonella , Bartonella , Enfermedades de los Bovinos , Dípteros , Enfermedades de las Cabras , Enfermedades de los Caballos , Animales , Animales Domésticos , Bartonella/genética , Infecciones por Bartonella/epidemiología , Infecciones por Bartonella/veterinaria , Bovinos , ADN Bacteriano/genética , Cobayas , Caballos , Perú/epidemiología , OvinosRESUMEN
Introduction: Malaria is still an important vector-borne disease in the New World tropics. Despite the recent decline in malaria due to Plasmodium falciparum infection in Africa, a rise in Plasmodium infections has been detected in several low malaria transmission areas in Latin America. One of the main obstacles in the battle against malaria is the lack of innovative tools to assess malaria transmission risk, and the behavioral plasticity of one of the main malaria vectors in Latin America, Anopheles darlingi. Methods: We used human IgG antibodies against mosquito salivary gland proteins as a measure of disease risk. Whole salivary gland antigen (SGA) from Anopheles darlingi mosquitoes was used as antigen in Western blot experiments, in which a ~65 kDa protein was visualized as the main immunogenic band and sent for sequencing by mass spectrometry. Apyrase and peroxidase peptides were designed and used as antigens in an ELISA-based test to measure human IgG antibody responses in people with different clinical presentations of malaria. Results: Liquid chromatography-mass spectrometry revealed 17 proteins contained in the ~65 kDa band, with an apyrase and a peroxidase as the two most abundant proteins. Detection of IgG antibodies against salivary antigens by ELISA revealed a significant higher antibody levels in people with malaria infection when compared to uninfected volunteers using the AnDar_Apy1 and AnDar_Apy2 peptides. We also detected a significant positive correlation between the anti-peptides IgG levels and antibodies against the Plasmodium vivax and P. falciparum antigens PvMSP1 and PfMSP1. Odd ratios suggest that people with higher IgG antibodies against the apyrase peptides were up to five times more likely to have a malaria infection. Conclusion: Antibodies against salivary peptides from An. darlingi salivary gland proteins may be used as biomarkers for malaria risk.
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Anopheles , Plasmodium , África , Animales , Formación de Anticuerpos , Humanos , Mosquitos Vectores , Plasmodium falciparum , Proteínas y Péptidos SalivalesRESUMEN
BACKGROUND: The humoral immune response against Anopheles salivary glands proteins in the vertebrate host can reflect the intensity of exposure to Anopheles bites and the risk of Plasmodium infection. In Colombia, the identification of exposure biomarkers is necessary due to the several Anopheles species circulating. The purpose of this study was to evaluate risk of malaria infection by measuring antibody responses against salivary glands extracts from Anopheles (Nyssorhynchus) albimanus and Anopheles (Nys.) darlingi and also against the gSG6-P1 peptide of Anopheles gambiae in people residing in a malaria endemic area in the Colombian Pacific coast. METHODS: Dried blood spots samples were eluted to measure the IgG antibodies against salivary gland extracts of An. albimanus strains STECLA (STE) and Cartagena (CTG) and An. darlingi and the gSG6-P1 peptide by ELISA in uninfected people and microscopic and submicroscopic Plasmodium carriers from the Colombia Pacific Coast. A multiple linear mixed regression model, Spearman correlation, and Mann-Whitney U-test were used to analyse IgG data. RESULTS: Significant differences in specific IgG levels were detected between infected and uninfected groups for salivary glands extracts from An. albimanus and for gSG6-P1, also IgG response to CTG and gSG6-P1 peptide were positively associated with the IgG response to Plasmodium falciparum in the mixed model. CONCLUSION: The CTG and STE An. albimanus salivary glands extracts are a potential source of new Anopheles salivary biomarkers to identify exposure to the main malaria vector and to calculate risk of disease in the Colombian Pacific coast. Also, the gSG6-P1 peptide has the potential to quantify human exposure to the subgenus Anopheles vectors in the same area.
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Anopheles/inmunología , Inmunoglobulina G/biosíntesis , Malaria/epidemiología , Mosquitos Vectores/inmunología , Proteínas y Péptidos Salivales/inmunología , Adolescente , Animales , Infecciones Asintomáticas/epidemiología , Niño , Preescolar , Colombia/epidemiología , Estudios Transversales , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunoglobulina G/sangre , Estudios Longitudinales , Malaria/inmunología , Malaria/transmisión , Masculino , Oportunidad Relativa , Océano Pacífico , Factores de RiesgoRESUMEN
BACKGROUND: The common bed bug, Cimex lectularius, is an obligatory blood-feeding ectoparasite that requires a blood meal to molt and produce eggs. Their frequent biting to obtain blood meals and intimate association with humans increase the potential for disease transmission. However, despite more than 100 years of inquiry into bed bugs as potential disease vectors, they still have not been conclusively linked to any pathogen or disease. This ecological niche is extraordinarily rare, given that nearly every other blood-feeding arthropod is associated with some type of human or zoonotic disease. Bed bugs rely on the bacteria Wolbachia as an obligate endosymbiont to biosynthesize B vitamins, since they acquire a nutritionally deficient diet, but it is unknown if Wolbachia confers additional benefits to its bed bug host. In some insects, Wolbachia induces resistance to viruses such as Dengue, Chikungunya, West Nile, Drosophila C and Zika, and primes the insect immune system in other blood-feeding insects. Wolbachia might have evolved a similar role in its mutualistic association with the bed bug. In this study, we evaluated the influence of Wolbachia on virus replication within C. lectularius. METHODS: We used feline calicivirus as a model pathogen. We fed 40 bed bugs from an established line of Wolbachia-cured and a line of Wolbachia-positive C. lectularius a virus-laden blood meal, and quantified the amount of virus over five time intervals post-feeding. The antibiotic rifampicin was used to cure bed bugs of Wolbachia. RESULTS: There was a significant effect of time post-feeding, as the amount of virus declined by ~90% over 10 days in both groups, but no significant difference in virus titer was observed between the Wolbachia-positive and Wolbachia-cured groups. CONCLUSIONS: These findings suggest that other mechanisms are involved in virus suppression within bed bugs, independent of the influence of Wolbachia, and our conclusions underscore the need for future research.
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Chinches/microbiología , Chinches/virología , Calicivirus Felino/crecimiento & desarrollo , Calicivirus Felino/aislamiento & purificación , Interacciones Microbianas , Carga Viral , Wolbachia/crecimiento & desarrollo , AnimalesRESUMEN
BACKGROUND: The age range for supracondylar humeral fractures spans from 1 to 14 years of age; most published studies have analyzed patients as non-age-segregated cohorts. Some isolated studies focused on the upper age range, demonstrating a male predominance and more severe fractures. The purpose of the current study was to analyze a large cohort of patients with surgically treated supracondylar humeral fractures at the low end of the age range (<2 years of age). METHODS: Patients <2 years of age were identified from surgical billing records. Pin constructs were categorized as lateral column-only fixation or medial and lateral column fixation. All patients were followed through fracture-healing. Substantial loss of reduction was defined as a Baumann angle that changed ≥10° between surgery and healing or as a lateral rotation percentage (i.e., Gordon index) of ≥50% at the time of healing. The Fisher exact test was used for statistical analysis. RESULTS: One hundred and three patients met our inclusion criteria. There were 69 female and 34 male patients (a 2:1 female-to-male ratio). Two patients did not have adequate follow-up radiographs. Of the 46 patients with bicolumnar fixation, 5 (11%) demonstrated loss of reduction compared with 20 (36%) of 55 patients with lateral column-only fixation. This difference between the groups was significant (p = 0.005). The group with lateral column-only fixation had 4.7-times-higher odds of loss of reduction (95% confidence interval, 1.6 to 13.8). A subset of patients had in-cast imaging that allowed calculation of the posterior sagittal cast index (a measure of cast fit). Eight of 15 patients who had a posterior sagittal cast index of ≥0.20 experienced loss of reduction, while only 1 of 19 patients with a cast index value of <0.20 had loss of reduction (p = 0.004). CONCLUSIONS: Supracondylar humeral fractures were twice as common in females in this very young cohort. We also found a nearly 5-times-higher odds of loss of reduction when fracture fixation was of the lateral column only. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
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Fijación Interna de Fracturas/métodos , Fracturas del Húmero/cirugía , Clavos Ortopédicos , Femenino , Estudios de Seguimiento , Fijación Interna de Fracturas/instrumentación , Curación de Fractura , Humanos , Fracturas del Húmero/diagnóstico por imagen , Fracturas del Húmero/epidemiología , Lactante , Masculino , Ohio/epidemiología , Radiografía , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
The common bed bug, Cimex lectularius harbors the endosymbiotic microorganism, Wolbachia (wCle), in a gonad-associated bacteriome as an obligate nutritional mutualist. The obligatory nature of this association suggests that all individuals in C. lectularius populations would be infected with wCle. However, studies spanning the past several decades have reported variation in both infection frequency and relative abundance of wCle in field-collected samples of bed bugs. Since the growth kinetics of wCle is poorly understood, the objective of this study was to quantify wCle over the life cycle of two strains of C. lectularius. Our results highlight that wCle is dynamic during bed bug development, changing relative to life stage, intermolt stage, and blood-fed status. These results suggest new hypotheses about the coordination of Wolbachia growth and regression with its host's physiology and endocrine events. The observed quantitative modulation of wCle during the bed bug life cycle and during periods of starvation may explain the disparities in wCle infections reported in field-collected C. lectularius.
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Chinches/microbiología , Simbiosis , Wolbachia/crecimiento & desarrollo , Animales , ADN/genética , Femenino , Cinética , Larva/microbiologíaRESUMEN
Tennis elbow is a common musculoskeletal condition affecting middle-aged patients with symptoms usually lasting from 6 months to 2 years. The vast majority of individuals will respond to conservative therapy; however, some will require surgical intervention. A new treatment system has been developed for use with ultrasound guidance in the ultrasonic microresection of tendinopathic tissue. This technology has been implemented in the TX1 Tissue Removal System and is used to treat various tendinopathies by debridement using targeted ultrasonic energy. We describe the surgical technique for the TX1 system as well as provide pain and functional outcome scores for a series of patients with recalcitrant lateral epicondylitis treated with percutaneous tenotomy with ultrasonic energy utilizing ultrasound guidance.
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Desbridamiento/métodos , Codo de Tenista/cirugía , Tenotomía/métodos , Ultrasonido , Humanos , Satisfacción del Paciente , Reinserción al Trabajo , Tendones/diagnóstico por imagen , Tendones/cirugía , Ultrasonografía Intervencional , Escala Visual AnalógicaRESUMEN
The house fly, Musca domestica L. (Diptera: Muscidae), is a disease vector of mechanically transmitted pathogens including bacteria, viruses, and protozoans. Opportunities for pathogen transmission can increase as fly longevity increases. Dietary preferences play an important role in insect longevity; therefore, we investigated house fly preferences, sucrose availability, and caloric constraints on house fly longevity. Experimental goals were: 1) to test the effects of calorie restriction on survival of house flies by manipulating concentrations of erythritol (low caloric content) and sucrose (high caloric content), and comparing commercial sweeteners of differing calorie content, 2) to identify house fly preferences for either erythritol or sucrose, and 3) to evaluate the insecticidal activity or toxicity of erythritol on house flies. Our data show that house flies may prefer high calorie options when given a choice and that house fly longevity likely increases as calorie content increases. Additionally, no significant differences in longevity were observed between the water only control (zero calories) and erythritol treatments. This suggests that decreased survival rates and death could be the result of starvation rather than insecticidal activity. This research furthers our understanding of house fly survival and sugar-feeding behavior.
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Eritritol/farmacología , Moscas Domésticas/efectos de los fármacos , Insecticidas/farmacología , Sacarosa/metabolismo , Edulcorantes/toxicidad , Animales , Restricción Calórica , Conducta de Elección , Femenino , Moscas Domésticas/fisiología , MasculinoRESUMEN
Three insecticides commonly used for mosquito and sand fly control were applied 30 min to 3 h after sunset during June and July 2010, at Camp Buehring, Kuwait, to determine the relative quantity of pesticides to height and distance traveled in a hot desert environment. A BVA dilution oil was used for the control. Oil-based adulticides were sprayed using a truck-mounted Curtis DynaFog Maxi-Pro 4 ultra-low volume (ULV) sprayer. Malathion (Fyfanon ULV, 96% active ingredient [AI]), resmethrin (Scourge 4+12, 4% AI), pyrethrins (ULD BP-300, 3% AI), and BVA Spray 13 (100% refined petroleum distillate) were mixed with Uvitex optical brightener fluorescent dye and applied at 2 speeds on evenings when wind speed was less than 16.1 km/h (10 mph). Collection targets using biodegradable cotton ribbons (1 m×2.5 cm) were later read with a fluorometer to quantify the amount of insecticide deposited on targets set at heights of 15.2, 76.2, and 152.4 cm (6, 30, and 60 in.) and distances of 1.5, 6.1, 15.2, 30.5, 61.0, and 91.4 m (5, 20, 50, 100, 200, and 300 ft). Mean insecticide deposition across all distances was 31% on 76.2-cm targets and 49% on 152.4-cm targets, while 15.2-cm targets typically collected <20% of test spray. Mean ground temperatures were typically within 5°C of air temperatures at 152.4 cm and within 1 to 5°C of air at 15.2 cm or 76.2 cm. Collectively, mean insecticide deposition was 80% at or above 76.2 cm for all insecticides. This finding may explain in part why control of low-flying phlebotomine sand flies with ULV insecticides has been met with less than optimal success by US military forces deployed in the Middle East.
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Clima Desértico , Control de Insectos/métodos , Insecticidas/química , Psychodidae/efectos de los fármacos , Salud Pública , Animales , Humanos , Insecticidas/administración & dosificación , Insecticidas/farmacología , Kuwait , Malatión/administración & dosificación , Malatión/química , Malatión/farmacología , Nebulizadores y Vaporizadores , Residuos de Plaguicidas , Petróleo , Piretrinas/administración & dosificación , Piretrinas/química , Piretrinas/farmacologíaRESUMEN
A Yersinia pseudotuberculosis (Yptb) murine model of lung infection was previously developed using the serotype III IP2666NdeI strain, which robustly colonized lungs but only sporadically disseminated to the spleen and liver. We demonstrate here that a serotype Ib Yptb strain, IP32953, colonizes the lungs at higher levels and disseminates more efficiently to the spleen and liver compared with IP2666NdeI . The role of adhesins was investigated during IP32953 lung infection by constructing isogenic Δail, Δinv, ΔpsaE and ΔyadA mutants. An IP32953ΔailΔyadA mutant initially colonized but failed to persist in the lungs and disseminate to the spleen and liver. Yptb expressing these adhesins selectively bound to and targeted neutrophils for translocation of Yops. This selective targeting was critical for virulence because persistence of the ΔailΔyadA mutant was restored following intranasal infection of neutropenic mice. Furthermore, Ail and YadA prevented killing by complement-mediated mechanisms during dissemination to and/or growth in the spleen and liver, but not in the lungs. Combined, these results demonstratethat Ail and YadA are critical, redundant virulence factors during lung infection, because they thwart neutrophils by directing Yop-translocation specifically into these cells.
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Adhesinas Bacterianas/metabolismo , Proteínas de la Membrana Bacteriana Externa/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas de la Membrana/metabolismo , Neutrófilos/inmunología , Neutrófilos/microbiología , Yersiniosis/inmunología , Yersinia pseudotuberculosis/fisiología , Adhesinas Bacterianas/genética , Animales , Proteínas de la Membrana Bacteriana Externa/genética , Modelos Animales de Enfermedad , Eliminación de Gen , Interacciones Huésped-Patógeno , Hígado/microbiología , Pulmón/inmunología , Pulmón/microbiología , Ratones , Bazo/microbiología , Factores de Virulencia/genética , Factores de Virulencia/metabolismo , Yersiniosis/microbiología , Yersinia pseudotuberculosis/inmunologíaRESUMEN
Many pathogens are capable of causing a fulminant infection in pulmonary tissues of mammals. Animal models have provided an extensive understanding of the genetic and molecular mechanisms of bacterial pathogenesis as well as host immune response in the lungs. Many clinically relevant Gram-negative bacteria are host-restricted. Thus, the powerful, informative tools of mouse models are not available for study with these organisms. However, over the past 30 years, enterprising work has demonstrated the utility of pulmonary infection with enteric pathogens. Such infection models have increased our understanding host-pathogen interactions in these organisms. Here, we provide a review and comparison of lung models of infection with enteric, Gram-negative bacteria relative to naturally occurring lung pathogens.
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Modelos Animales de Enfermedad , Infecciones por Enterobacteriaceae/microbiología , Infecciones por Enterobacteriaceae/patología , Enterobacteriaceae/fisiología , Neumonía Bacteriana/microbiología , Neumonía Bacteriana/patología , Animales , Enterobacteriaceae/patogenicidad , RatonesRESUMEN
The field of cyanobacterial biofuel production is advancing rapidly, yet we know little of the basic biology of these organisms outside of their photosynthetic pathways. We aimed to gain a greater understanding of how the cyanobacterium Synechocystis PCC 6803 (Synechocystis, hereafter) modulates its cell surface. Such understanding will allow for the creation of mutants that autoflocculate in a regulated way, thus avoiding energy intensive centrifugation in the creation of biofuels. We constructed mutant strains lacking genes predicted to function in carbohydrate transport or synthesis. Strains with gene deletions of slr0977 (predicted to encode a permease component of an ABC transporter), slr0982 (predicted to encode an ATP binding component of an ABC transporter) and slr1610 (predicted to encode a methyltransferase) demonstrated flocculent phenotypes and increased adherence to glass. Upon bioinformatic inspection, the gene products of slr0977, slr0982, and slr1610 appear to function in O-antigen (OAg) transport and synthesis. However, the analysis provided here demonstrated no differences between OAg purified from wild-type and mutants. However, exopolysaccharides (EPS) purified from mutants were altered in composition when compared to wild-type. Our data suggest that there are multiple means to modulate the cell surface of Synechocystis by disrupting different combinations of ABC transporters and/or glycosyl transferases. Further understanding of these mechanisms may allow for the development of industrially and ecologically useful strains of cyanobacteria. Additionally, these data imply that many cyanobacterial gene products may possess as-yet undiscovered functions, and are meritorious of further study.
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Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Microbiología Industrial , Ingeniería Metabólica , Antígenos O/genética , Synechocystis/genética , Transportadoras de Casetes de Unión a ATP/deficiencia , Transportadoras de Casetes de Unión a ATP/genética , Adhesión Bacteriana , Biocombustibles , Transporte Biológico , Vidrio , Metiltransferasas/deficiencia , Metiltransferasas/genética , Familia de Multigenes , Antígenos O/metabolismo , Synechocystis/metabolismoRESUMEN
Yersinia delivers Yops into numerous types of cultured cells, but predominantly into professional phagocytes and B cells during animal infection. The basis for this cellular tropism during animal infection is not understood. This work demonstrates that efficient and specific Yop translocation into phagocytes by Yersinia pseudotuberculosis (Yptb) is a multi-factorial process requiring several adhesins and host complement. When WT Yptb or a multiple adhesin mutant strain, ΔailΔinvΔyadA, colonized tissues to comparable levels, ΔailΔinvΔyadA translocated Yops into significantly fewer cells, demonstrating that these adhesins are critical for translocation into high numbers of cells. However, phagocytes were still selectively targeted for translocation, indicating that other bacterial and/or host factors contribute to this function. Complement depletion showed that complement-restricted infection by ΔailΔinvΔyadA but not WT, indicating that adhesins disarm complement in mice either by prevention of opsonophagocytosis or by suppressing production of pro-inflammatory cytokines. Furthermore, in the absence of the three adhesins and complement, the spectrum of cells targeted for translocation was significantly altered, indicating that Yersinia adhesins and complement direct Yop translocation into neutrophils during animal infection. In summary, these findings demonstrate that in infected tissues, Yersinia uses adhesins both to disarm complement-dependent killing and to efficiently translocate Yops into phagocytes.
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Adhesinas Bacterianas/metabolismo , Proteínas del Sistema Complemento/metabolismo , Fagocitos/metabolismo , Infecciones por Yersinia pseudotuberculosis/metabolismo , Yersinia pseudotuberculosis/metabolismo , Adhesinas Bacterianas/genética , Animales , Proteínas del Sistema Complemento/genética , Ratones , Fagocitos/microbiología , Fagocitos/patología , Transporte de Proteínas/genética , Yersinia pseudotuberculosis/genética , Infecciones por Yersinia pseudotuberculosis/genética , Infecciones por Yersinia pseudotuberculosis/patologíaRESUMEN
LcrF (VirF), a transcription factor in the multiple adaptational response (MAR) family, regulates expression of the Yersinia type III secretion system (T3SS). Yersinia pseudotuberculosis lcrF-null mutants showed attenuated virulence in tissue culture and animal models of infection. Targeting of LcrF offers a novel, antivirulence strategy for preventing Yersinia infection. A small molecule library was screened for inhibition of LcrF-DNA binding in an in vitro assay. All of the compounds lacked intrinsic antibacterial activity and did not demonstrate toxicity against mammalian cells. A subset of these compounds inhibited T3SS-dependent cytotoxicity of Y. pseudotuberculosis toward macrophages in vitro. In a murine model of Y. pseudotuberculosis pneumonia, two compounds significantly reduced the bacterial burden in the lungs and afforded a dramatic survival advantage. The MAR family of transcription factors is well conserved, with members playing central roles in pathogenesis across bacterial genera; thus, the inhibitors could have broad applicability.
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Proteínas Bacterianas/antagonistas & inhibidores , Bencimidazoles/farmacología , Neumonía Bacteriana/patología , Factores de Transcripción/antagonistas & inhibidores , Infecciones por Yersinia pseudotuberculosis/patología , Yersinia pseudotuberculosis/efectos de los fármacos , Yersinia pseudotuberculosis/patogenicidad , Animales , Antibacterianos/administración & dosificación , Antibacterianos/síntesis química , Antibacterianos/química , Antibacterianos/farmacología , Proteínas Bacterianas/metabolismo , Bencimidazoles/administración & dosificación , Bencimidazoles/síntesis química , Bencimidazoles/química , Línea Celular , Modelos Animales de Enfermedad , Femenino , Humanos , Pulmón/microbiología , Macrófagos/microbiología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Neumonía Bacteriana/tratamiento farmacológico , Neumonía Bacteriana/microbiología , Neumonía Bacteriana/mortalidad , Factores de Transcripción/metabolismo , Resultado del Tratamiento , Virulencia , Yersinia pseudotuberculosis/metabolismo , Infecciones por Yersinia pseudotuberculosis/tratamiento farmacológico , Infecciones por Yersinia pseudotuberculosis/microbiología , Infecciones por Yersinia pseudotuberculosis/mortalidadRESUMEN
BACKGROUND: Heart rate can affect cardiac function, but the importance of rates lower than 100 paced beats per minute is unknown. We therefore sought to evaluate the impact of different heart rates on ejection fraction, 6-minute walk, and peak oxygen consumption (VO2) in heart failure patients. METHODS AND RESULTS: We studied 13 pacemaker-dependent New York Heart Association Class III patients with ejection fraction <40%, age 66 +/- 13. Eligible patients included those pacing at least 75% of the time at a lower set rate of 60 ppm. This was a 3-period randomized blinded crossover study. Patients were assigned to pace at 60, 75, or 90 ppm (with rate responsivity to 20 ppm above the lower rate) for 2 months at each setting. At the end of each period, ejection fraction (by nuclear ventriculography) and exercise tolerance (by peak VO2 and 6-minute walk) were assessed. Ejection fraction, peak VO2, and 6-minute walk distance were significantly different among the 3 heart rates. All 3 were depressed at 90 ppm. A heart rate of 90 also led to more clinical deterioration and premature discontinuation from that period. CONCLUSIONS: Pacing at a heart rate of 90 led to lower ejection fraction, VO2, 6-minute walk distance and clinical evidence of worsening heart failure as compared with slower heart rates.
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Estimulación Cardíaca Artificial/métodos , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/terapia , Frecuencia Cardíaca , Anciano , Enfermedad Crónica , Estudios Cruzados , Prueba de Esfuerzo , Tolerancia al Ejercicio , Femenino , Humanos , Masculino , Consumo de Oxígeno , Volumen Sistólico , Resultado del TratamientoRESUMEN
Yersinia pseudotuberculosis infects many mammals and birds including humans, livestock, and wild rodents and can be recovered from the lungs of infected animals. To determine the Y. pseudotuberculosis factors important for growth during lung infection, we developed an intranasal model of infection in mice. Following intranasal inoculation, we monitored both bacterial growth in lungs and dissemination to systemic tissues. Intranasal inoculation with as few as 18 CFU of Y. pseudotuberculosis caused a lethal lung infection in some mice. Over the course of 7 days, wild-type Y. pseudotuberculosis replicated to nearly 1 x 10(8) CFU/g of lung in BALB/c mice, induced histopathology in lungs consistent with pneumonia, but disseminated sporadically to other tissues. In contrast, a Delta yopB deletion strain was attenuated in this model, indicating that translocation of Yersinia outer proteins (Yops) is essential for virulence. Additionally, a Delta yopH null mutant failed to grow to wild-type levels by 4 days postintranasal inoculation, but deletions of any other single effector YOP did not attenuate lung colonization 4 days postinfection. Strains with deletions in yopH and any one of the other known effector yop genes were more attenuated that the Delta yopH strain, indicating a unique role for yopH in lungs. In summary, we have characterized the progression of a lung infection with an enteric Yersinia pathogen and shown that YopB and YopH are important in lung colonization and dissemination. Furthermore, this lung infection model with Y. pseudotuberculosis can be used to test potential therapeutics against Yersinia and other gram-negative infections in lungs.