RESUMEN
Zebu cattle (Bos indicus) is reported to be more resistant towards harmful environmental factors than taurine cattle (Bos taurus). A few hundred zebu cattle are kept in Switzerland and in contrast to the Swiss indigenous breeds, infectious hoof disease in zebu is not observed. Therefore, we compared the prevalence of three ruminant hoof pathogens in zebu and taurine cattle. These included Treponema spp., Fusobacterium necrophorum and Dichelobacter nodosus which are associated with bovine digital dermatitis (BDD), different bovine hoof diseases and ovine footrot, respectively. Interdigital swabs and punch biopsies from hind feet of slaughter animals were tested for the three pathogens by PCR. Sixty zebu from eight farms were compared to a convenience sample of 20 taurine cattle from 17 farms. Treponema spp. associated with BDD were not detected in zebu while 23â¯% of animals and 50â¯% of farms were positive for benign D. nodosus, with results indicating environmental contamination rather than colonization. Taurine cattle showed 35â¯% of animals and 41â¯% of farms positive for T. phagedenis while 90â¯% of animals and 94â¯% of farms were colonized by D. nodosus as indicated by a 500-fold higher bacterial load than in zebu. The difference in prevalence of the two pathogens between zebu and taurine cattle was highly significant. F. necrophorum was as well only detected in taurine cattle with values of 15â¯% of animals and 17.7â¯% of farms, being significantly different at the animal level. Furthermore, genetic analysis of Swiss zebu indicates high genomic diversity and clear separation from taurine cattle. This is the first evidence that zebu show resistance towards colonization by bacterial hoof pathogens in contrast to taurine cattle.
Asunto(s)
Enfermedades de los Bovinos , Dichelobacter nodosus , Fusobacterium necrophorum , Pezuñas y Garras , Animales , Bovinos , Enfermedades de los Bovinos/microbiología , Suiza/epidemiología , Pezuñas y Garras/microbiología , Dichelobacter nodosus/genética , Dichelobacter nodosus/patogenicidad , Fusobacterium necrophorum/genética , Fusobacterium necrophorum/patogenicidad , Fusobacterium necrophorum/aislamiento & purificación , Treponema/genética , Treponema/aislamiento & purificación , Treponema/clasificación , Enfermedades del Pie/veterinaria , Enfermedades del Pie/microbiología , Prevalencia , Resistencia a la Enfermedad , Infecciones por Fusobacterium/veterinaria , Infecciones por Fusobacterium/microbiologíaRESUMEN
Objetivou-se comparar o efeito in silico do florfenicol nas doses de 20 e 30 mg/Kg em ovinos pelas vias intravenosa (IV) e intramuscular (IM), usando a modelagem PK/PD. Realizou-se uma simulação de Monte Carlo com base nos dados de concentração plasmática de um estudo publicado anteriormente. Calculou-se a área sob a curva (ASC) e as taxas de eficácia do florfenicol para os efeitos bacteriostático, bactericida e de erradicação bacteriológica. A dose de 20 mg/Kg IV demonstrou efeitos de erradicação de 100, 93 e 0% para CIM de 0,5, 1 e acima, respectivamente. O efeito bacteriostático foi de 99 e 90% para CIM de 4 e 2 µg/ml, enquanto o bactericida foi de 14% para CIM de 2 µg/ml. A dose de 30 mg/Kg IV apresentou 100% de erradicação para CIM de 1 µg/mL e 100% de efeito bactericida para CIM de 2 µg/mL. Há 100% de efeito bacteriostático em CIM de 4 µg/ml. As doses de 20 e 30 mg/Kg IM mostraram 100% de erradicação para CIM até 1 µg/mL e 0% para CIM maiores. O efeito bacteriostático foi mantido em 100% para uma CIM de 4 µg/mL em ambas as doses. Este estudo mostra o efeito de erradicação bacteriológica do florfenicol nas doses de 20 e 30 mg/Kg, IV e IM. Recomenda-se que seja feito um estudo de eficácia in vivo com a dose de 30mg/Kg IM em ovinos infectados por F. necrophorum com MIC superior a 2 µg/mL.
We aimed to compare the in silico effect of florfenicol at doses of 20 and 30 mg/Kg in sheep by intravenous (IV) and intramuscular (IM) routes, using PK/PD modeling. We performed a Monte Carlo simulation based on plasma concentration data from a previously published study. We calculated the area under the curve (AUC) and the efficacy rates of florfenicol to bacteriostatic, bactericidal, and bacteriological eradication effects. The dose of 20 mg/Kg IV demonstrated 100, 93, and 0% eradication effects for MICs of 0.5, 1, and above, respectively. The bacteriostatic effect was 99 and 90% for MIC of 4 and 2 µg/ml, while the bactericide was 14% for MIC of 2 µg/ml. The 30 mg/Kg IV dose showed 100% eradication for MIC of 1 µg/mL and 100% bactericidal effect for MIC of 2 µg/mL. There is a 100% of bacteriostatic effect at MIC of 4 µg/ml. Doses of 20 and 30 mg/Kg IM showed 100% eradication for MIC up to 1 µg/mL and 0% for MIC above. The bacteriostatic effect was maintained at 100% for a MIC of 4 µg/mL at both doses. This study shows the bacteriological eradication effect of florfenicol at doses of 20 and 30 mg/Kg, IV, and IM. Therefore, we recommend an in vivo efficacy study with a dose of 30mg/Kg IM in sheep infected with F. necrophorum with MIC greater than two µg/mL.
Asunto(s)
Animales , Ovinos/anomalías , Técnicas Bacteriológicas/veterinaria , Panadizo Interdigital/tratamiento farmacológico , Fusobacterium necrophorum/patogenicidad , Antibacterianos/uso terapéutico , Método de MontecarloRESUMEN
The SARS-CoV-2 outbreak has disrupted the delivery of routine healthcare services on a global scale. With many regions suspending the provision of non-essential healthcare services, there is a risk that patients with common treatable illnesses do not receive prompt treatment, leading to more serious and complex presentations at a later date. Lemierre's syndrome is a potentially life-threatening and under-recognised sequela of an oropharyngeal or dental infection. It is characterised by septic embolisation of the gram-negative bacillus Fusobacterium necrophorum to a variety of different organs, most commonly to the lungs. Thrombophlebitis of the internal jugular vein is frequently identified. We describe an atypical case of Lemierre's syndrome involving the brain, liver and lungs following a dental infection in a young male who delayed seeking dental or medical attention due to a lack of routine services and concerns about the SARS-CoV-2 outbreak.
Asunto(s)
Absceso Encefálico , Infecciones por Coronavirus , Cuidados Críticos/métodos , Diagnóstico Tardío , Fusobacterium necrophorum , Absceso Piógeno Hepático , Nódulos Pulmonares Múltiples , Pandemias , Neumonía Viral , Cuarentena , Enfermedades Dentales , Antibacterianos/administración & dosificación , Anticoagulantes/administración & dosificación , Betacoronavirus , Absceso Encefálico/diagnóstico por imagen , Absceso Encefálico/etiología , COVID-19 , Deterioro Clínico , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/prevención & control , Diagnóstico Diferencial , Fusobacterium necrophorum/aislamiento & purificación , Fusobacterium necrophorum/patogenicidad , Humanos , Síndrome de Lemierre/diagnóstico , Síndrome de Lemierre/etiología , Síndrome de Lemierre/fisiopatología , Absceso Piógeno Hepático/diagnóstico por imagen , Absceso Piógeno Hepático/etiología , Absceso Piógeno Hepático/cirugía , Imagen por Resonancia Magnética/métodos , Masculino , Nódulos Pulmonares Múltiples/diagnóstico por imagen , Nódulos Pulmonares Múltiples/etiología , Pandemias/prevención & control , Aceptación de la Atención de Salud , Neumonía Viral/epidemiología , Neumonía Viral/prevención & control , Cuarentena/métodos , Cuarentena/psicología , SARS-CoV-2 , Tomografía Computarizada por Rayos X/métodos , Enfermedades Dentales/complicaciones , Enfermedades Dentales/diagnóstico , Enfermedades Dentales/microbiología , Resultado del Tratamiento , Adulto JovenRESUMEN
Here we report an outbreak of an atypical, ulcerative dermatitis in North Country mule lambs, located in South Gloucestershire, UK. The lesions, which appeared to be contagious, occured between the coronary band and the carpal joint as a focal, well demarcated, circular, ulcerative dermatitis. Histopathological examination of the lesion biopsies revealed areas of ulceration, epidermal hyperplasia, suppurative dermatitis and granulation tissue. Clumped keratohyalin granules and intracellular keratinocyte oedema (ballooning degeneration) were evident within lesion biopsies, consistent with an underlying viral aetiology. A PCR-based microbiological investigation failed to detect bovine digital dermatitis-associated treponeme phylogroups, Dichelobacter nodosus, Staphylococcus aureus, Dermatophilus congolensis or Chordopoxvirinae virus DNA. However, 3 of the 10 (30 %) and 6 of 10 (60 %) lesion samples were positive for Fusobacterium necrophorum and Streptococcus dysgalactiae DNA, respectively. Contralateral limb swabs were negative by all standard PCR assays. To better define the involvement of F. necrophorum in the aetiology of these lesions, a qPCR targeting the rpoB gene was employed and confirmed the presence of F. necrophorum DNA in both the control and lesions swab samples, although the mean F. necrophorum genome copy number detected in the lesion swab samples was â¼19-fold higher than detected in the contralateral control swab samples (245 versus 4752 genome copies/µl, respectively; P < 0.001). Although we have not been able to conclusively define an aetiological agent, the presence of both F. necrophorum and S. dysgalactiae in the majority of lesions assayed supports their role in the aetiopathogenesis of these lesions.
Asunto(s)
Infecciones Bacterianas/veterinaria , Úlcera de la Córnea/patología , Úlcera de la Córnea/veterinaria , Enfermedades de las Ovejas/microbiología , Factores de Edad , Animales , Infecciones Bacterianas/patología , Biopsia/veterinaria , Úlcera de la Córnea/microbiología , Fusobacterium necrophorum/genética , Fusobacterium necrophorum/patogenicidad , Pezuñas y Garras/microbiología , Pezuñas y Garras/patología , Ganado/microbiología , Extremidad Inferior/microbiología , Extremidad Inferior/patología , Ovinos , Enfermedades de las Ovejas/patología , Oveja Doméstica/microbiología , Streptococcus/genética , Streptococcus/patogenicidad , Reino UnidoRESUMEN
Lemierre's syndrome, also known as post-anginal septicemia or necrobacillosis, is characterized by bacteremia, internal jugular vein thrombophlebitis, and metastatic septic emboli secondary to acute pharyngeal infections. Modern physicians have "forgotten" this disease. The most common causative agent of Lemierre's syndrome is Fusobacterium necrophorum, followed by Fusobacterium nucleatum and anaerobic bacteria such as streptococci, staphylococci, and Klebsiella pneumoniae. The causative focus mostly originated from pharyngitis or tonsillitis, accounting for over 85% of the cases of Lemierre's syndrome. Pneumonia or pleural empyema is the most common metastatic infection in Lemierre's syndrome. Antimicrobial therapy should be prescribed for 3-6 weeks. The treatment regimens include metronidazole and ß-lactam antibiotics. In recent years, the antibiotic stewardship program has resulted in decreased antibiotic prescription for upper respiratory tract infections. The incidence of Lemierre's syndrome has increased over the past decade. F. necrophorum is an underestimated cause of acute pharyngitis or tonsillitis. A high index of suspicion is required for the differential diagnosis of acute tonsillopharyngitis with persistent neck pain and septic syndrome.
Asunto(s)
Bacterias Anaerobias/patogenicidad , Bacterias/patogenicidad , Enfermedades Transmisibles Emergentes/microbiología , Síndrome de Lemierre/tratamiento farmacológico , Sepsis/microbiología , Antibacterianos/uso terapéutico , Bacterias/clasificación , Fusobacterium necrophorum/patogenicidad , Humanos , Síndrome de Lemierre/diagnóstico , Síndrome de Lemierre/microbiología , Faringitis/microbiologíaRESUMEN
Several Finnish dairy herds have suffered from outbreaks of interdigital phlegmon (IP). In these new types of outbreaks, morbidity was high and clinical signs severe, resulting in substantial economic losses for affected farms. In our study, we visited 18 free stall dairy herds experiencing an outbreak of IP and 3 control herds without a similar outbreak. From a total of 203 sampled cows, 60 suffered from acute stage IP. We demonstrated that acute phase response of bovine IP was evident and therefore an appropriate analgesic should be administered in the treatment of affected animals. The response was most apparent in herds with high morbidity in IP and with a bacterial infection comprising Fusobacterium necrophorum and Dichelobacter nodosus, indicating that combination of these two bacterial species affect the severity of the disease.
Asunto(s)
Reacción de Fase Aguda , Enfermedades de los Bovinos/microbiología , Enfermedades del Pie/veterinaria , Infecciones por Bacterias Gramnegativas/veterinaria , Pezuñas y Garras/patología , Enfermedades de las Ovejas/microbiología , Animales , Bovinos , Enfermedades de los Bovinos/sangre , Estudios Transversales , Industria Lechera , Dichelobacter nodosus/patogenicidad , Brotes de Enfermedades/veterinaria , Femenino , Finlandia/epidemiología , Enfermedades del Pie/sangre , Enfermedades del Pie/microbiología , Fusobacterium necrophorum/patogenicidad , Infecciones por Bacterias Gramnegativas/sangre , Pezuñas y Garras/microbiología , Índice de Severidad de la Enfermedad , Ovinos , Enfermedades de las Ovejas/sangreRESUMEN
Sites of persistence of bacterial pathogens contribute to disease dynamics of bacterial diseases. Footrot is a globally important bacterial disease that reduces health and productivity of sheep. It is caused by Dichelobacter nodosus, a pathogen apparently highly specialised for feet, while Fusobacterium necrophorum, a secondary pathogen in footrot is reportedly ubiquitous on pasture. Two prospective longitudinal studies were conducted to investigate the persistence of D. nodosus and F. necrophorum in sheep feet, mouths and faeces, and in soil. Molecular tools were used to detect species, strains and communities. In contrast to the existing paradigm, F. necrophorum persisted on footrot diseased feet, and in mouths and faeces; different strains were detected in feet and mouths. D. nodosus persisted in soil and on diseased, but not healthy, feet; similar strains were detected on both healthy and diseased feet of diseased sheep. We conclude that D. nodosus and F. necrophorum depend on sheep for persistence but use different strategies to persist and spread between sheep within and between flocks. Elimination of F. necrophorum would be challenging due to faecal shedding. In contrast D. nodosus could be eliminated if all footrot-affected sheep were removed and fade out of D. nodosus occurred in the environment before re-infection of a foot.
Asunto(s)
Infecciones Bacterianas/microbiología , Panadizo Interdigital/microbiología , Enfermedades de las Ovejas/microbiología , Animales , Infecciones Bacterianas/patología , Infecciones Bacterianas/veterinaria , Dichelobacter nodosus/patogenicidad , Panadizo Interdigital/patología , Infecciones por Fusobacterium/microbiología , Infecciones por Fusobacterium/patología , Infecciones por Fusobacterium/veterinaria , Fusobacterium necrophorum/patogenicidad , Pezuñas y Garras/microbiología , Pezuñas y Garras/patología , Ovinos/genética , Ovinos/microbiología , Enfermedades de las Ovejas/patología , Virulencia/genéticaRESUMEN
Fusobacterium necrophorum is a Gram negative, rod-shaped and aero tolerant anaerobe. In animals, it is an opportunistic pathogen frequently associated with necrotic infections, generally called necrobacillosis, such as calf diphtheria, foot rot and liver abscesses in cattle. Two subspecies exist: subsp. necrophorum and subsp. funduliforme. Among several virulence factors, leukotoxin (Lkt) is considered to be a major factor and a protective antigen. The objective of the study was to utilize BL3 cells and measure the release of lactic dehydrogenase to quantify Lkt activity of F. necrophorum. The assay was used to examine the effects of storage and handling conditions, growth media, polymyxin B addition on the cytotoxicity and evaluate Lkt activities of F. necrophorum strains isolated from bovine liver abscesses and foot rot. The Lkt activity peaked at 9â¯h of incubation. There was a significant decrease in the cytotoxicity measured in the samples after each freeze and thaw cycle. No difference was observed in the cytotoxicity for the samples handled aerobically versus anaerobically. Lkt activities of strains grown in anaerobic Brain-Heart Infusion broth were higher compared to Vegitone broth. A small reduction in the cytotoxicity activity was observed after the addition of polymyxin. The Lkt activity was consistently higher in strains of subsp. necrophorum than subsp. funduliforme of liver abscess origin. Among the strains isolated from cattle foot rot, Lkt activities of subsp. necrophorum strains appear to be much more variable. Use of BL3 cells in combination of lactic acid dehydrogenase assay appears to be a simple and valid assay to measure Lkt activity of F. necrophorum.
Asunto(s)
Enfermedades de los Bovinos/microbiología , Exotoxinas/toxicidad , Infecciones por Fusobacterium/veterinaria , Fusobacterium necrophorum/aislamiento & purificación , Fusobacterium necrophorum/patogenicidad , Factores de Virulencia/toxicidad , Animales , Bovinos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Panadizo Interdigital/microbiología , Infecciones por Fusobacterium/microbiología , L-Lactato Deshidrogenasa/análisis , Absceso Hepático/microbiología , Absceso Hepático/veterinariaRESUMEN
BACKGROUND: Recent reports have reported an increase in the incidence of acute mastoiditis because of Fusobacterium necrophorum. However, the crude incidence and the specific clinical and laboratory characteristics of F. necrophorum mastoiditis in children have not been described. Our aim was to describe these features to identify high-risk patients. METHODS: The electronic medical records of all children with acute mastoiditis at a tertiary medical center between July 2011 and December 2015 were analyzed. Using a stepwise logistic regression to identify independent risk factors for F. necrophorum, we formulated a predictive model. RESULTS: F. necrophorum was identified in 13% (19/149) of mastoiditis cases with an identifiable agent. Its incidence increased 7-fold from 2.8% in 2012 to 20.4% in 2015 (P = 0.02). F. necrophorum infection had unique clinical, laboratory and prognostic features. The vast majority had complications and underwent surgical intervention. The predictive model used 4 parameters to define high-risk patients for F. necrophorum infection at admission: females, winter/spring season, prior antibiotic treatment and a C-reactive protein value >20 mg/dL (area under receiver operating characteristic curve 0.929). CONCLUSIONS: Clinicians should be aware of the increasing incidence of F. necrophorum mastoiditis and consider anaerobic cultures and specific anaerobic coverage in high-risk patients.
Asunto(s)
Enfermedades Transmisibles Emergentes/microbiología , Infecciones por Fusobacterium/microbiología , Fusobacterium necrophorum/patogenicidad , Mastoiditis/microbiología , Enfermedad Aguda/epidemiología , Adolescente , Factores de Edad , Antibacterianos/uso terapéutico , Proteína C-Reactiva/análisis , Niño , Preescolar , Enfermedades Transmisibles Emergentes/tratamiento farmacológico , Enfermedades Transmisibles Emergentes/epidemiología , Femenino , Infecciones por Fusobacterium/tratamiento farmacológico , Humanos , Incidencia , Lactante , Israel/epidemiología , Masculino , Mastoiditis/tratamiento farmacológico , Mastoiditis/epidemiología , Factores de Riesgo , Estaciones del AñoRESUMEN
BACKGROUND: Longtime follow-up studies on patients with pharyngotonsillitis are rare. We aimed to describe the patterns of new visits for a sore throat, complications and tonsillectomy during 2 years in a cohort of patients with pharyngotonsillitis and non-infected controls. METHODS: A retrospective chart review was performed on a cohort of patients with acute sore throat (n = 207), and non-infected controls (n = 108). New visits, complications and tonsillectomy within 2 years was recorded and analyzed in relation to microbiological findings at inclusion. RESULTS: Patients with Group A streptococci (GAS) (12/66) reconsulted more often within 30 days than patients with no GAS (9/141) (p = 0.009) and patients with F. necrophorum (2/29). After 2 years, we observed no significant differences in reconsultations with regard to aetiology at inclusion. A single complication was recorded and 5 patients were planned for tonsillectomy. CONCLUSIONS: Group A streptococci were the sole aetiological agent associated with recurrent sore throat while F. necrophorum did not distinguish itself as a major cause of either recurrent infection or complications in this cohort. More studies, preferably with the focus on adolescents, are needed before F. necrophorum can be considered an important cause of pharyngotonsillitis.
Asunto(s)
Faringitis/microbiología , Faringitis/virología , Adolescente , Adulto , Antibacterianos/uso terapéutico , Estudios de Casos y Controles , Resfriado Común/complicaciones , Femenino , Estudios de Seguimiento , Infecciones por Fusobacterium/microbiología , Fusobacterium necrophorum/patogenicidad , Humanos , Masculino , Persona de Mediana Edad , Faringitis/complicaciones , Faringitis/tratamiento farmacológico , Estudios Retrospectivos , Streptococcus pyogenes/patogenicidad , Tonsilectomía/efectos adversos , Tonsilitis/complicaciones , Tonsilitis/microbiología , Tonsilitis/cirugía , Adulto JovenRESUMEN
Fusobacterium necrophorum is a gram-negative anaerobic bacterium that is the causative agent of the invasive disease Lemierre's syndrome. In addition, it is also associated with peritonsillar abscess formation and otitis media in small children. Recent research has shown that F. necrophorum may be involved in pharyngotonsillitis especially in adolescent and young adults and that it may be the second most common bacterial cause of pharyngotonsillitis after Streptococcus pyogenes (Group A streptococci). Peritonsillar abscesses and Lemierre's syndrome due to F. necrophorum are also found in this age group, suggesting that they may be complications of F. necrophorum pharyngotonsillitis. In this review we present the present knowledge about the role of F. necrophorum in pharyngotonsillitis with special emphasis on the age distribution. We argue that F. necrophorum is an important pathogen involved in pharyngotonsillitis in the age group of 13-40 years of age and we urge clinical microbiology labs to set up the appropriate techniques to be able to detect F. necrophorum from throat swabs.
Asunto(s)
Fusobacterium necrophorum/patogenicidad , Síndrome de Lemierre/diagnóstico , Otitis Media/diagnóstico , Absceso Peritonsilar/diagnóstico , Faringitis/diagnóstico , Tonsilitis/diagnóstico , Adolescente , Adulto , Distribución por Edad , Factores de Edad , Antibacterianos/uso terapéutico , Niño , Femenino , Fusobacterium necrophorum/fisiología , Humanos , Síndrome de Lemierre/tratamiento farmacológico , Síndrome de Lemierre/microbiología , Síndrome de Lemierre/patología , Masculino , Orofaringe/efectos de los fármacos , Orofaringe/microbiología , Orofaringe/patología , Otitis Media/tratamiento farmacológico , Otitis Media/microbiología , Otitis Media/patología , Absceso Peritonsilar/tratamiento farmacológico , Absceso Peritonsilar/microbiología , Absceso Peritonsilar/patología , Faringitis/tratamiento farmacológico , Faringitis/microbiología , Faringitis/patología , Factores Sexuales , Tonsilitis/tratamiento farmacológico , Tonsilitis/microbiología , Tonsilitis/patologíaRESUMEN
Ovine footrot is characterised by interdigital dermatitis (ID) and by the separation of the skin and hoof horn (under-running footrot). Dichelobacter nodosus is the essential pathogen causing footrot; the role of other microorganisms in this disease remains unclear. The aims of this study were (i) to investigate the colonisation of D nodosus, Fusobacterium necrophorum and Treponema species in biopsies from the ovine interdigital skin of healthy, ID and footrot-affected feet and (ii) to characterise the virulence of D nodosus strains in those biopsies. Postslaughter biopsy samples (n=241) were collected and analysed by real-time PCR to determine prevalence and load of the different bacterial species. The highest prevalence and load of D nodosus were found on feet with ID. The vast majority of samples contained virulent D nodosus and some samples contained both virulent and benign D nodosus Notably, the more pathogenic subspecies of F necrophorum was found in samples from UK sheep. Our findings provide further insights into the role bacterial colonisation may play in the early stage of ID and in the progression towards footrot.
Asunto(s)
Panadizo Interdigital/microbiología , Enfermedades de las Ovejas/microbiología , Animales , Dichelobacter nodosus/aislamiento & purificación , Dichelobacter nodosus/patogenicidad , Fusobacterium necrophorum/aislamiento & purificación , Fusobacterium necrophorum/patogenicidad , Ovinos , Treponema/aislamiento & purificación , Treponema/patogenicidad , VirulenciaRESUMEN
Fusobacterium necrophorum has been detected in pneumonic bighorn sheep (BHS; Ovis canadensis ) lungs, in addition to the aerobic respiratory pathogens Mannheimia haemolytica , Bibersteinia trehalosi , Pasteurella multocida , and Mycoplasma ovipneumoniae . Similar to M. haemolytica , F. necrophorum produces a leukotoxin. Leukotoxin-induced lysis and degranulation of polymorphonuclear leukocytes (PMNs) and macrophages are responsible for acute inflammation and lung tissue damage characteristic of M. haemolytica -caused pneumonia. As one approach in elucidating the role of F. necrophorum in BHS pneumonia, we determined the frequency of the presence of F. necrophorum in archived pneumonic BHS lung tissues, and susceptibility of BHS leukocytes to F. necrophorum leukotoxin. A species-specific PCR assay detected F. necrophorum in 37% of pneumonic BHS lung tissues (total tested n=70). Sequences of PCR amplicons were similar to the less virulent F. necrophorum subsp. funduliforme. Fusobacterium necrophorum leukotoxin exhibited cytotoxicity to BHS PMNs and peripheral blood mononuclear cells. As with the M. haemolytica leukotoxin, F. necrophorum leukotoxin was more toxic to BHS PMNs than domestic sheep PMNs. It is likely that F. necrophorum enters the lungs after M. haemolytica and other aerobic respiratory pathogens enter the lungs and initiate tissue damage, thereby creating a microenvironment that is conducive for anaerobic bacterial growth. In summary, Fusobacterium leukotoxin is highly toxic for BHS leukocytes; however, based on the PCR findings, it is unlikely to play a direct role in the development of BHS pneumonia.
Asunto(s)
Fusobacterium necrophorum/patogenicidad , Neumonía/veterinaria , Enfermedades de las Ovejas , Borrego Cimarrón/microbiología , Animales , Leucocitos Mononucleares , Mannheimia haemolytica , Ovinos , Estados UnidosRESUMEN
New findings show that Fusobacterium necrophorum, the bacterium responsible for most cases of Lemierre's disease, a relatively rare condition that is sometimes called "the forgotten disease," is also the culprit for more sore throats than Group A strep bacterium among college-aged patients. However, as there is no point-of-care test for F. necrophorum, providers need to rely on physical examination when determining whether a sore throat is due to the bacterial infection. In an analysis of 312 college students, investigators detected F. necrophorum in more than 20% of patients with symptoms of sore throat. Group A strep was only detected in 10% of the cases, and Group C or G strep was detected in 9% of the cases. Researchers note that the F. necrophorum bacterium is associated with both Lemierre's disease and most cases involving a peritonsillar abscess, a deep infection of the head or neck that occurs most commonly in young adults. Infections caused by F. necrophorum can be effectively treated with penicillin or a cephalosporin, but do not typically respond to azithromycin.
Asunto(s)
Infecciones por Fusobacterium/diagnóstico , Fusobacterium necrophorum/patogenicidad , Faringitis/microbiología , Diagnóstico Diferencial , Servicio de Urgencia en Hospital , Infecciones por Fusobacterium/complicaciones , Infecciones por Fusobacterium/tratamiento farmacológico , Fusobacterium necrophorum/aislamiento & purificación , HumanosRESUMEN
Analysis of bacterial populations in situ provides insights into pathogen population dynamics and potential reservoirs for disease. Here we report a culture-independent study of ovine footrot (FR); a debilitating bacterial disease that has significant economic impact on sheep farming worldwide. Disease begins as an interdigital dermatitis (ID), which may then progress to separation of the hoof horn from the underlying epidermis causing severe footrot (SFR). Dichelobacter nodosus is the causative agent of ovine FR, however, the role of Fusobacterium necrophorum and other bacteria present in the environment and on the feet of sheep is less clear. The objective of this study was to use fluorescence in situ hybridisation (FISH) to detect, localise and quantify D. nodosus, F. necrophorum and the domain Bacteria from interdigital skin biopsies of healthy, ID- and SFR-affected feet. D. nodosus and F. necrophorum populations were restricted primarily to the epidermis, but both were detected more frequently in feet with ID or SFR than in healthy feet. D. nodosus cell counts were significantly higher in feet with ID and SFR (p<0.05) than healthy feet, whereas F. necrophorum cell counts were significantly higher only in feet with SFR (p<0.05) than healthy feet. These results, together with other published data, indicate that D. nodosus likely drives pathogenesis of footrot from initiation of ID to SFR; with D. nodosus cell counts increasing prior to onset of ID and SFR. In contrast, F. necrophorum cell counts increase after SFR onset, which may suggest an accessory role in disease pathogenesis, possibly contributing to the severity and duration of SFR.
Asunto(s)
Dichelobacter nodosus/patogenicidad , Panadizo Interdigital/microbiología , Fusobacterium necrophorum/patogenicidad , Enfermedades de las Ovejas/microbiología , Oveja Doméstica , Animales , Dichelobacter nodosus/fisiología , Fusobacterium necrophorum/fisiología , Pezuñas y Garras/patología , Hibridación Fluorescente in Situ/veterinaria , Dinámica Poblacional , Ovinos , Piel/microbiologíaRESUMEN
Fusobacterium necrophorum is a Gram-negative obligate anaerobe associated with several diseases in humans and animals. Despite its increasing clinical significance, there is little or no data on the relationship between its metabolism and virulence. Previous studies have shown that bacteria grown under iron-limitation express immunogenic antigens similar to those generated in vivo. Thus, this paper describes the relationship between F. necrophorum subsp. necrophorum (Fnn) metabolism and the expression of the encoded putative virulence factors under iron-restricted conditions. At the midlog phase, iron limitation reduced Fnn growth but the cell density was dependent on the size of the inoculum. Preferential utilization of glucose-1-phosphate, d-mannitol and l-phenylalanine; production of 2-hydroxycaproic acid and termination of dimethyl sulphide production were major Fnn response-factors to iron limitation. Ultimately, iron restriction resulted in an increased ability of Fnn to metabolize diverse carbon sources and in the expression of stress-specific virulence factors. Iron starvation in low Fnn cell density was associated with the up-regulation of haemagglutinin (HA) and leukotoxin (lktA) genes (2.49 and 3.72 fold change respectively). However, Fnn encoded Haemolysin (Hly), yebN homologue (febN) and tonB homologue, were down-regulated (0.15, 0.79 and 0.33, fold changes respectively). Interestingly, cell density appeared to play a regulatory role in the final bacteria cell biomass, induction of a metabolic gene expression and the expression pattern virulence factors in Fnn suggesting the role of a cell density-associated regulatory factor. This report suggest that future studies on differential expression of bacterial genes under altered environmental condition(s) should consider testing the effect of cell concentrations as this is often neglected in such studies. In conclusion, iron restriction induces preferential utilization of carbon sources and altered metabolism in Fnn with associated changes in the expression pattern of the virulence factors.
Asunto(s)
Fusobacterium necrophorum/genética , Fusobacterium necrophorum/metabolismo , Fusobacterium necrophorum/patogenicidad , Regulación Bacteriana de la Expresión Génica , Hierro/metabolismo , Factores de Virulencia/genética , Animales , Proteínas Bacterianas/genética , Carbono/metabolismo , Simulación por Computador , Fusobacterium necrophorum/crecimiento & desarrollo , Proteínas de la Membrana/genética , Datos de Secuencia Molecular , Ovinos/microbiologíaRESUMEN
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Asunto(s)
Humanos , Masculino , Anciano , Osteomielitis/microbiología , Mediastinitis/microbiología , Fusobacterium necrophorum/patogenicidad , Esternón/microbiologíaRESUMEN
Anaerobic bacterial infection is often accompanied by abscess formation; however, few in vivo studies have been published with descriptive data specifically evaluating antimicrobial activity in the presence of abscesses. The aim of this study was to establish a murine model of anaerobic infection with abscess formation and to verify the utility of this model for evaluating the in vivo efficacy of an antimicrobial agent. A clinical isolate of Fusobacterium necrophorum was inoculated into the caudal vein of immunocompetent BALB/c mice at 10(8) c.f.u. per mouse. Changes in body weight, bacterial load and histopathology of key organs were evaluated. After inoculation, bacterial counts in the liver increased from 10(4) to 10(8) c.f.u. after 1-3 days, and liver abscess formation was observed on the day following infection. Abscess formation and bacterial growth were not observed in other organs. In this model, 3 days of treatment with 5 mg metronidazole kg(-1) eradicated F. necrophorum in the liver; however, a reduction in bacterial load was not observed with 0.05 mg metronidazole kg(-1). In this study, we established a novel murine model of F. necrophorum liver abscess via haematogenous infection that may be useful for investigating in vivo antimicrobial activity against anaerobic abscesses and understanding the pathogenesis of F. necrophorum infection.
Asunto(s)
Modelos Animales de Enfermedad , Infecciones por Fusobacterium/microbiología , Infecciones por Fusobacterium/patología , Fusobacterium necrophorum/patogenicidad , Absceso Hepático/microbiología , Absceso Hepático/patología , Administración Intravenosa , Animales , Antibacterianos/administración & dosificación , Carga Bacteriana , Peso Corporal , Histocitoquímica , Hígado/microbiología , Hígado/patología , Masculino , Metronidazol/administración & dosificación , Ratones , Ratones Endogámicos BALB CRESUMEN
Fusobacterium necrophorum, a Gram-negative, anaerobic bacterium, is an opportunistic animal and human pathogen that causes a variety of infections termed necrobacillosis. There are 2 subspecies of F. necrophorum (subsp. necrophorum and subsp. funduliforme) that differ morphologically and biochemically and in virulence. Leukotoxin, a secreted protein, is considered to be the major virulence factor. In camelids, F. necrophorum causes a variety of infections, generally involving the lips, tongue, pharynx, interdigital spaces, foot pad, larynx, mandible, or maxillary bones. The objective of the current study was to characterize the presumptive Fusobacterium isolates from a variety of necrotic infections in llama (Lama glama) and alpaca (Vicugna pacos) and determine whether the strains possess leukotoxin activities. A total of 7 isolates from alpaca and 2 isolates from llama were characterized. Based on growth characteristics in broth culture, and biochemical and polymerase chain reaction analyses, all 9 isolates belonged to subsp. necrophorum and possessed the putative hemagglutinin gene. Western blot analysis with antileukotoxin antibodies raised in rabbit showed the presence of leukotoxin protein in the culture supernatant of all isolates. Furthermore, flow cytometry of the culture supernatants demonstrated cytotoxicity to bovine and alpaca polymorphonuclear leukocytes (PMNs). The extent of cytotoxicity to either alpaca or bovine PMNs differed among camelid strains. The cytotoxicity of many of the camelid strains was higher (P < 0.05) toward alpaca PMNs compared to bovine PMNs. Fusobacterium necrophorum isolates from llama and alpaca are similar to bovine isolates, and leukotoxin may be a major virulence factor.