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1.
Am J Mens Health ; 18(5): 15579883241280826, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39340388

RESUMEN

Prostate cancer disproportionately affects Black men in the United States, leading to higher mortality rates and health disparities. In addition, based on historical mistreatment and discrimination and the resulting distrust of the medical system, Black populations are consistently underrepresented in health care-related research. Addressing these challenges requires community-driven approaches integrating diverse perspectives and fostering equitable health outcomes. This article describes the formation and impact of The Multidisciplinary Health Outcomes Research and Economics (MORE) Lab Community Advisory Board (CAB) at The University of Oklahoma Health Sciences. We purposefully recruited Black men with CaP and Black health care professionals to serve on a CAB and advise on ongoing research to address quality of life (QoL) issues in ethnically diverse Black CaP survivors. The CAB seeks to mitigate CaP disparities and improve health equity by empowering Black voices and promoting collaborative research practices. The MORE Lab CAB has successfully provided a venue for community members to contribute to designing a culturally relevant research program to improve the QoL in ethnically diverse Black men with CaP. The CAB has been instrumental in developing research goals and tools, implementing a series of town hall meetings to educate and support Black CaP survivors, and disseminating research findings. In conclusion, CABs are potentially critical in guiding research, enhancing community engagement, and advocating for culturally responsive health interventions.


Asunto(s)
Comités Consultivos , Negro o Afroamericano , Neoplasias de la Próstata , Humanos , Masculino , Negro o Afroamericano/psicología , Neoplasias de la Próstata/etnología , Investigación Participativa Basada en la Comunidad , Persona de Mediana Edad , Participación de la Comunidad , Estados Unidos , Calidad de Vida , Oklahoma , Anciano
2.
Qual Life Res ; 33(10): 2705-2719, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39008143

RESUMEN

PURPOSE: This study examined the health-related quality of life (HRQoL) among ethnically diverse Black men (BM) with prostate cancer (CaP) in the United States. METHODS: A convergent parallel mixed-methods design, employing both qualitative and quantitative research, involved recruiting Black CaP survivors through multiple channels. The target population was native-born BM (NBBM), African-born BM (ABBM), and Caribbean-born BM (CBBM). QoL for all men was assessed using The Functional Assessment Cancer Therapy-Prostate (FACT-P) measure, which includes five domains: physical- (PWB), emotional- (EWB), social-(SWB), and functional-wellbeing (FWB), and a CaP subscale (PCS). A subset of men completed qualitative interviews. Demographic and clinical characteristics were also collected. RESULTS: Black CaP survivors aged 49-85 participated in the study (n = 108), with a subset (n = 31) completing a qualitative interview. Participants were mainly NBBM (72.2%) and treated with radiotherapy (51.9%). The FACT-P scale total mean score (± SD) was 114 ± 24.1 (theoretical range 0-156), with lower scores reported on the SWB, FWB, and EWB domains. The mixed-methods findings approach included meta-inferences derived from integrating the corresponding quantitative and qualitative data, covering all the domains within the FACT-P. CONCLUSION: Black CaP survivors experienced significant burdens that impacted their overall HRQoL. The analysis revealed impacts on physical, social, and emotional well-being, with variations among ethnic groups suggesting the need for culturally tailored interventions. EWB was also profoundly impacted by CaP treatment, with universal emotional burdens emphasized across all groups. Healthcare providers must recognize and address these multifaceted needs to promote better outcomes and HRQoL for Black CaP survivors.


Asunto(s)
Negro o Afroamericano , Supervivientes de Cáncer , Neoplasias de la Próstata , Investigación Cualitativa , Calidad de Vida , Humanos , Masculino , Neoplasias de la Próstata/psicología , Neoplasias de la Próstata/terapia , Calidad de Vida/psicología , Anciano , Persona de Mediana Edad , Supervivientes de Cáncer/psicología , Anciano de 80 o más Años , Negro o Afroamericano/psicología , Negro o Afroamericano/estadística & datos numéricos , Estados Unidos , Encuestas y Cuestionarios
3.
J Cancer Surviv ; 2024 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-38805150

RESUMEN

PURPOSE: Prostate cancer (CaP) is the most common cancer in Black men (BM), and the number of Black CaP survivors is rapidly increasing. Although Black immigrants are among the fastest-growing and most heterogeneous ethnic groups in the USA, limited data exist regarding their CaP experiences. Therefore, this study aimed to explore and model the experiences of ethnically diverse Black men with CaP. METHODS: In-depth interviews were conducted with 34 participants: native-born BM (NBBM) (n = 17), African-born BM (ABBM) (n = 11), and Caribbean-born BM (CBBM) (n = 6) CaP survivors recruited through QR code-embedded flyers posted in Black businesses, clinics, social media platforms, and existing research networks within the USA. Guided by Charmaz's constructivist grounded theory methodology, the interviews were analyzed using constant comparison following key stages of initial, focused, and theoretical coding using Atlas.ti v23. RESULTS: Participants were thirty-four men aged 49-84 years (mean ± SD, 66 ± 8). Most were married (77%), likely to be diagnosed at stage I (35%), and treated with radiotherapy (56%). Our study findings explored the complex trajectory of Black prostate cancer (CaP) survivors, unveiling a comprehensive model termed "Journeying through Unfamiliar Terrain." Comprising three phases and 11 sub-phases, this model uniquely captures the pre-diagnosis awareness and post-treatment adaptation among survivors. CONCLUSION: The resulting theoretical model delineates the entire CaP survivorship process among BM, providing contextual and conceptual understanding for developing interventions and enhancing patient-centered care for ethnically diverse CaP survivors, pivotal in bridging the gaps in survivorship research and healthcare practices. IMPLICATIONS FOR CANCER SURVIVORS: Black CAP survivors experience significant burdens and challenges that impact their overall quality of life. Understanding the factors that impact the complex survivorship journey can inform design and implementation of interventions to address the multiple challenges and thus improve quality of life.

4.
Front Oncol ; 13: 1263347, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37799466

RESUMEN

Extranodal extension (ENE) is a pattern of cancer growth from within the lymph node (LN) outward into perinodal tissues, critically defined by disruption and penetration of the tumor through the entire thickness of the LN capsule. The presence of ENE is often associated with an aggressive cancer phenotype in various malignancies including head and neck squamous cell carcinoma (HNSCC). In HNSCC, ENE is associated with increased risk of distant metastasis and lower rates of locoregional control. ENE detected on histopathology (pathologic ENE; pENE) is now incorporated as a risk-stratification factor in human papillomavirus (HPV)-negative HNSCC in the eighth edition of the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC) TNM classification. Although ENE was first described almost a century ago, several issues remain unresolved, including lack of consensus on definitions, terminology, and widely accepted assessment criteria and grading systems for both pENE and ENE detected on radiological imaging (imaging-detected ENE; iENE). Moreover, there is conflicting data on the prognostic significance of iENE and pENE, particularly in the context of HPV-associated HNSCC. Herein, we review the existing literature on ENE in HNSCC, highlighting areas of controversy and identifying critical gaps requiring concerted research efforts.

6.
J Otolaryngol Head Neck Surg ; 51(1): 37, 2022 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-36192808

RESUMEN

BACKGROUND: Advanced squamous cell carcinoma (SCCa) of the oral cavity is often not amenable to curative-intent therapy due to tumor location, tumor size, or comorbidities. CASE PRESENTATION: A 51-year-old male patient with human immunodeficiency virus and on highly active antiretroviral therapy (HAART) presented with a cT4aN2c SCCa of the tongue. He received a preoperative single course of Quad-Shot radiation therapy to 14 Gy in 4 fractions followed by surgical resection. Patient had no residual carcinoma on surgical pathology and no evidence of disease on subsequent clinical and radiological exams. CONCLUSIONS: To our knowledge, this is the first case of pathologic complete response for a patient on HAART following a single cycle of the Quad-Shot regimen for advanced oral cavity SCCa. Protease inhibitors in HAART can induce spontaneous tumor regression via inhibition of proteasome function and activation of apoptosis, and thus act as a cancer therapeutic.


Asunto(s)
Carcinoma de Células Escamosas , Infecciones por VIH , Neoplasias de la Boca , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/radioterapia , Terapia Combinada , VIH , Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Boca/radioterapia , Inhibidores de Proteasas/uso terapéutico , Complejo de la Endopetidasa Proteasomal/uso terapéutico
7.
Vaccine ; 38(14): 2960-2970, 2020 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-32111525

RESUMEN

Nontypeable strains of Haemophilus influenzae (NTHi) are one of the most common cause of otitis media and the most frequent infection associated with exacerbations of chronic obstructive pulmonary disease; there is currently no vaccine in the U.S. to prevent NTHi. Using bioinformatics and structural vaccinology, we previously identified several NTHi species-conserved and sequence-conserved peptides that mediate passive protection in the rat model of infection. Using these, and similar peptides, we designed Hi Poly 1, a Bacterial Vaccine Polypeptide, comprising 9 unique peptides from 6 different surface proteins. Recombinant Hi Poly 1 was purified by affinity chromatography. Forty chinchillas were immunized three times with 200 µg of Hi Poly 1 with alum adjuvant; similarly, 41 controls were immunized with adjuvant alone. The average Log2 IgG titer among immunized animals was 17.04, and IgG antibodies against each component peptide were detected. In the infant rat model, antisera from immunized chinchillas provided significant passive protection compared to PBS (p = 0.01) and pre-immune sera (p = 0.03). In the established chinchilla model of NTHi otitis media, the vaccinated group cleared infection faster than the control group as indicated by significantly decreased positive findings on video-otoscopy (p < 0.0001) and tympanometry (p = 0.0002) on day 7, and for middle ear fluid obtained by aspiration (p = 0.0001) on day 10 post-infection. Using 12 representative NTHi strains in a Live-Cell ELISA, greater antibody binding to each strain was detected with post Hi Poly 1 than the pre-immune chinchilla antisera. The data from this proof-of-principle study demonstrate the effectiveness of Hi Poly 1 against the NTHi in two relevant preclinical models of bacteremia and otitis media as well as surface antibody binding across the species. The Bacterial Vaccine Polypeptide approach to a vaccine against NTHi also serves as a paradigm for development of similar vaccines to protect against other bacteria.


Asunto(s)
Proteínas Bacterianas/inmunología , Infecciones por Haemophilus , Vacunas contra Haemophilus/inmunología , Proteínas de la Membrana/inmunología , Otitis Media , Animales , Anticuerpos Antibacterianos/sangre , Chinchilla , Infecciones por Haemophilus/prevención & control , Haemophilus influenzae , Sueros Inmunes/inmunología , Inmunoglobulina G/sangre , Otitis Media/microbiología , Otitis Media/prevención & control , Péptidos , Ratas
8.
Genome Announc ; 3(6)2015 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-26607889

RESUMEN

Nontypeable Haemophilus influenzae is an important cause of human disease. Strains were selected for genome sequencing to represent the breadth of nontypeable strains within the species, as previously defined by the electrophoretic mobility of 16 metabolic enzymes.

9.
Genome Announc ; 3(5)2015 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-26404588

RESUMEN

Haemophilus influenzae is an important cause of invasive disease. The infant rat is the accepted model of invasive H. influenzae disease. Here, we report the genome sequences of six nontypeable H. influenzae strains that establish bacteremia in the infant rat.

10.
PLoS One ; 10(9): e0136867, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26390432

RESUMEN

Nontypeable Haemophilus influenzae (NTHi) cause significant disease, including otitis media in children, exacerbations of chronic obstructive pulmonary disease, and invasive disease in susceptible populations. No vaccine is currently available to prevent NTHi disease. The interactions of NTHi and the human host are primarily mediated by lipooligosaccharide and a complex array of surface-exposed proteins (SEPs) that act as receptors, sensors and secretion systems. We hypothesized that certain SEPs are present in all NTHi strains and that a subset of these may be antibody accessible and represent protective epitopes. Initially we used 15 genomic sequences available in the GenBank database along with an additional 11 genomic sequences generated by ourselves to identify the core set of putative SEPs present in all strains. Using bioinformatics, 56 core SEPs were identified. Molecular modeling generated putative structures of the SEPs from which potential surface exposed regions were defined. Synthetic peptides corresponding to ten of these highly conserved surface-exposed regions were used to raise antisera in rats. These antisera were used to assess passive protection in the infant rat model of invasive NTHi infection. Five of the antisera were protective, thus demonstrating their in vivo antibody accessibility. These five peptide regions represent potential targets for peptide vaccine candidates to protect against NTHi infection.


Asunto(s)
Infecciones por Haemophilus/prevención & control , Haemophilus influenzae/inmunología , Animales , Sitios de Unión de Anticuerpos , Biología Computacional , Modelos Animales de Enfermedad , Epítopos , Infecciones por Haemophilus/inmunología , Vacunas contra Haemophilus , Sueros Inmunes , Modelos Moleculares , Ratas
11.
BMC Genomics ; 14: 925, 2013 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-24373462

RESUMEN

BACKGROUND: Haemophilus influenzae is a significant cause of childhood otitis media, and also has an absolute growth requirement for heme. Recent microarray studies using three H. influenzae isolates were used to propose a putative core of genes responsive to iron and heme levels. Included in the core modulon were thirty seven genes that are preferentially expressed under iron/heme limitation, most of which are directly involved with iron and or heme acquisition. In this report, the core iron/heme modulon was further refined following microarray analysis of two additional nontypeable H. influenzae isolates from patients with otitis media. The transcriptional status of the genes comprising the refined iron/heme core modulon was then assessed in vivo, in a chinchilla model of otitis media. These in vivo experiments were performed to address the hypothesis that iron and heme regulated genes are both highly expressed in vivo and important, during clinical infection. RESULTS: Microarray analysis of two additional H. influenzae strains resulted in the definition of a core of iron/heme responsive genes. This core consisted of 35 genes maximally expressed under heme restriction and a further 20 genes maximally expressed in heme replete conditions. In vivo studies were performed with two nontypeable H. influenzae strains, 86-028NP and HI1722. The majority of operons identified as members of the core modulon by microarray were also actively upregulated in the chinchilla ear during otitis media. In 86-028NP, 70% of the operons were significantly upregulated while in HI1722 100% of the operons were upregulated in samples recovered from the chinchilla middle ear. CONCLUSION: This study elucidates a conserved core of H. influenzae genes the transcription of which is altered by the availability of iron and heme in the growth environment, and further assesses transcription of these genes in vivo. Elucidation of this modulon allows for identification of genes with unrecognized roles in iron/heme acquisition or homeostasis and/or potential roles in virulence. Defining these core genes is also of potential importance in identifying targets for therapeutic and vaccine designs since products of these genes are likely to be preferentially expressed during growth in iron/heme restricted sites of the human body.


Asunto(s)
Chinchilla/microbiología , Oído Medio/microbiología , Regulación Bacteriana de la Expresión Génica , Haemophilus influenzae/genética , Transcriptoma , Animales , Modelos Animales de Enfermedad , Hemo/metabolismo , Hierro/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Operón , Otitis Media/microbiología , Regulón , Transcripción Genética
12.
BMC Microbiol ; 13: 134, 2013 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-23767779

RESUMEN

BACKGROUND: The RNA binding protein Hfq of Haemophilus influenzae is highly homologous to Hfq from other bacterial species. In many of these other bacteria, Hfq affects the expression of a broad range of genes and enhances the ability to respond to stressful environments. However, the role of Hfq in H. influenzae is unknown. RESULTS: Deletion mutants of hfq were generated in the nontypeable H. influenzae strains R2866 and 86-028NP to assess the role of Hfq in these well characterized but genotypically and phenotypically divergent clinical isolates. A deletion mutation of hfq had no effect on growth of H. influenzae in nutrient rich media and had no effect on survival in several stressful conditions in vitro. However, the mutation resulted in a reduced ability to utilize heme from hemoglobin. The mutant and wild type strains were assessed for virulence and competitive fitness in models of invasive disease and otitis media. In the chinchilla model of otitis media, the hfq mutant of 86-028NP exhibited impaired competitive fitness when compared to its wild type progenitor but exhibited no apparent defect in virulence. In the infant rat model, deletion of hfq in R2866 resulted in reduced bacterial titers in blood and a shorter duration of infection when compared to the wild type strain in the competitive fitness study. CONCLUSION: We conclude that Hfq is involved in the utilization of essential nutrients and facilitates infection by H. influenzae.


Asunto(s)
Haemophilus influenzae/patogenicidad , Proteína de Factor 1 del Huésped/metabolismo , Factores de Virulencia/metabolismo , Animales , Animales Recién Nacidos , Bacteriemia/microbiología , Bacteriemia/patología , Carga Bacteriana , Chinchilla , Femenino , Eliminación de Gen , Infecciones por Haemophilus/microbiología , Infecciones por Haemophilus/patología , Haemophilus influenzae/genética , Hemo/metabolismo , Hemoglobinas/metabolismo , Proteína de Factor 1 del Huésped/genética , Otitis Media/microbiología , Otitis Media/patología , Ratas , Ratas Sprague-Dawley , Virulencia
13.
PLoS One ; 7(11): e50588, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23226321

RESUMEN

To prevent damage by reactive oxygen species, many bacteria have evolved rapid detection and response systems, including the OxyR regulon. The OxyR system detects reactive oxygen and coordinates the expression of numerous defensive antioxidants. In many bacterial species the coordinated OxyR-regulated response is crucial for in vivo survival. Regulation of the OxyR regulon of Haemophilus influenzae was examined in vitro, and significant variation in the regulated genes of the OxyR regulon among strains of H. influenzae was observed. Quantitative PCR studies demonstrated a role for the OxyR-regulated peroxiredoxin/glutaredoxin as a mediator of the OxyR response, and also indicated OxyR self-regulation through a negative feedback loop. Analysis of transcript levels in H. influenzae samples derived from an animal model of otitis media demonstrated that the members of the OxyR regulon were actively upregulated within the chinchilla middle ear. H. influenzae mutants lacking the oxyR gene exhibited increased sensitivity to challenge with various peroxides. The impact of mutations in oxyR was assessed in various animal models of H. influenzae disease. In paired comparisons with the corresponding wild-type strains, the oxyR mutants were unaffected in both the chinchilla model of otitis media and an infant model of bacteremia. However, in weanling rats the oxyR mutant was significantly impaired compared to the wild-type strain. In contrast, in all three animal models when infected with a mixture of equal numbers of both wild-type and mutant strains the mutant strain was significantly out competed by the wild-type strain. These findings clearly establish a crucial role for OxyR in bacterial fitness.


Asunto(s)
Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica , Haemophilus influenzae/genética , Haemophilus influenzae/fisiología , Regulón , Animales , Bacteriemia/microbiología , Catalasa/metabolismo , Femenino , Haemophilus influenzae/citología , Haemophilus influenzae/metabolismo , Hemo/metabolismo , Espacio Intracelular/metabolismo , Hierro/metabolismo , Cinética , Mutación , Otitis Media/microbiología , Estrés Oxidativo/genética , Peroxirredoxinas/metabolismo , Embarazo , Ratas , Especificidad de la Especie , Transcripción Genética
14.
J Microbiol Methods ; 91(3): 336-40, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23085534

RESUMEN

Awareness of the high degree of redundancy that occurs in several nutrient uptake pathways of Haemophilus influenzae led us to attempt to develop a quantitative STM method that could identify both null mutants and mutants with decreased fitness that remain viable in vivo. To accomplish this task we designed a modified STM approach that utilized a set of signature tagged wild-type (STWT) strains (in a single genetic background) as carriers for mutations in genes of interest located elsewhere in the genome. Each STWT strain differed from the others by insertion of a unique, Q-PCR-detectable, seven base pair tag into the same redundant gene locus. Initially ten STWTs were created and characterized in vitro and in vivo. As anticipated, the STWT strains were not significantly different in their in vitro growth. However, in the chinchilla model of otitis media, certain STWTs outgrew others by several orders of magnitude in mixed infections. Removal of the predominant STWT resulted in its replacement by a different predominant STWT on retesting. Unexpectedly we observed that the STWT exhibiting the greatest proliferation was animal dependent. These findings identify an inherent inability of the signature tag methodologies to accurately elucidate fitness in this animal model of infection and underscore the subtleties of H. influenzae gene regulation.


Asunto(s)
Técnicas Genéticas , Infecciones por Haemophilus/microbiología , Haemophilus influenzae/crecimiento & desarrollo , Haemophilus influenzae/genética , Viabilidad Microbiana , Mutación , Otitis Media/microbiología , Animales , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Chinchilla , Haemophilus influenzae/aislamiento & purificación , Fenotipo
15.
BMC Res Notes ; 5: 327, 2012 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-22731867

RESUMEN

BACKGROUND: Haemophilus influenzae requires heme for aerobic growth and possesses multiple mechanisms to obtain this essential nutrient. METHODS: An insertional mutation in tonB was constructed and the impact of the mutation on virulence and fitness in a chinchilla model of otitis media was determined. The tonB insertion mutant strain was significantly impacted in both virulence and fitness as compared to the wildtype strain in this model. CONCLUSIONS: The tonB gene of H. influenzae is required for the establishment and maintenance of middle ear infection in this chinchilla model of bacterial disease.


Asunto(s)
Proteínas Bacterianas/genética , Chinchilla/microbiología , Genes Bacterianos/genética , Aptitud Genética , Haemophilus influenzae/genética , Haemophilus influenzae/patogenicidad , Proteínas de la Membrana/genética , Otitis Media/microbiología , Animales , Modelos Animales de Enfermedad , Aptitud Genética/efectos de los fármacos , Infecciones por Haemophilus/microbiología , Infecciones por Haemophilus/patología , Haemophilus influenzae/efectos de los fármacos , Haemophilus influenzae/crecimiento & desarrollo , Hemo/farmacología , Mutación/genética , Otitis Media/patología , Otitis Media con Derrame/microbiología , Otitis Media con Derrame/patología , Virulencia/efectos de los fármacos
17.
BMC Microbiol ; 10: 113, 2010 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-20398325

RESUMEN

BACKGROUND: Haemophilus influenzae has an absolute aerobic growth requirement for either heme, or iron in the presence of protoporphyrin IX. Both iron and heme in the mammalian host are strictly limited in their availability to invading microorganisms. Many bacterial species overcome iron limitation in their environment by the synthesis and secretion of small iron binding molecules termed siderophores, which bind iron and deliver it into the bacterial cell via specific siderophore receptor proteins on the bacterial cell surface. There are currently no reports of siderophore production or utilization by H. influenzae. RESULTS: Comparative genomics revealed a putative four gene operon in the recently sequenced nontypeable H. influenzae strain R2846 that encodes predicted proteins exhibiting significant identity at the amino acid level to proteins involved in the utilization of the siderophore ferrichrome in other bacterial species. No siderophore biosynthesis genes were identified in the R2846 genome. Both comparative genomics and a PCR based analysis identified several additional H. influenzae strains possessing this operon. In growth curve assays strains containing the genes were able to utilize ferrichrome as an iron source. H. influenzae strains lacking the operon were unable to obtain iron from ferrichrome. An insertional mutation in one gene of the operon abrogated the ability of strains to utilize ferrichrome. In addition transcription of genes in the identified operon were repressible by high iron/heme levels in the growth media. CONCLUSIONS: We have identified an iron/heme-repressible siderophore utilization locus present in several nontypeable H. influenzae strains. The same strains do not possess genes encoding proteins associated with siderophore synthesis. The siderophore utilization locus may enable the utilization of siderophores produced by other microorganisms in the polymicrobial environmental niche of the human nasopharynx colonized by H. influenzae. This is the first report of siderophore utilization by H. influenzae.


Asunto(s)
Genes Bacterianos , Haemophilus influenzae/genética , Haemophilus influenzae/metabolismo , Operón , Sideróforos/genética , Sideróforos/metabolismo , Adulto , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/metabolismo , Niño , Mapeo Cromosómico , Ferricromo/metabolismo , Infecciones por Haemophilus/microbiología , Haemophilus influenzae/crecimiento & desarrollo , Haemophilus influenzae/aislamiento & purificación , Hemo/metabolismo , Humanos , Hierro/metabolismo , Familia de Multigenes , Transcripción Genética
18.
Microbiology (Reading) ; 156(Pt 4): 1188-1200, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20075041

RESUMEN

The Haemophilus influenzae ORF designated HI1275 in the Rd KW20 genomic sequence encodes a putative S-adenosyl methyltransferase with significant similarity to tellurite-resistance determinants (tehB) in other species. While the H. influenzae tehB can complement an Escherichia coli tehB mutation, thus restoring tellurite resistance, its role in H. influenzae is unknown. In a previous study defining the iron and haem modulon of H. influenzae, we showed that transcription of this gene in H. influenzae Rd KW20 increases during growth in iron- and haem-restricted media. Since iron and haem uptake genes, and other known virulence factors, constitute the majority of the iron- and haem-regulated gene set, we postulated that tehB may play a role in nutrient acquisition and/or the virulence of H. influenzae. A tehB mutant was constructed in the H. influenzae type b strain 10810 and was evaluated for growth defects in various supplemented media, as well as for its ability to cause infection in rat models of infection. Deletion of tehB leads to an increase in sensitivity both to tellurite and to the oxidizing agents cumene hydroperoxide, tert-butyl hydroperoxide and hydrogen peroxide. The tehB mutant additionally showed a significantly reduced ability to utilize free haem as well as several haem-containing moieties including haem-human serum albumin, haemoglobin and haemoglobin-haptoglobin. Examination of the regulation kinetics indicated that transcription of tehB was independent of both tellurite exposure and oxidative stress. Paired comparisons of the tehB mutant and the wild-type H. influenzae strain 10810 showed that tehB is required for wild-type levels of infection in rat models of H. influenzae invasive disease. To our knowledge this is the first report of a role for tehB in virulence in any bacterial species. These data demonstrate that H. influenzae tehB plays a role in both resistance to oxidative damage and haem uptake/utilization, protects H. influenzae from tellurite exposure, and is important for virulence of this organism in an animal model of invasive disease.


Asunto(s)
Proteínas Bacterianas/metabolismo , Infecciones por Haemophilus/microbiología , Haemophilus influenzae/metabolismo , Haemophilus influenzae/patogenicidad , Animales , Proteínas Bacterianas/genética , Regulación Bacteriana de la Expresión Génica , Haemophilus influenzae/genética , Hemo/metabolismo , Humanos , Estrés Oxidativo , Ratas , Virulencia
19.
BMC Res Notes ; 2: 166, 2009 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-19703293

RESUMEN

BACKGROUND: Haemophilus influenzae requires a porphyrin source for aerobic growth and possesses multiple mechanisms to obtain this essential nutrient. This porphyrin requirement may be satisfied by either heme alone, or protoporphyrin IX in the presence of an iron source. One protein involved in heme acquisition by H. influenzae is the periplasmic heme binding protein HbpA. HbpA exhibits significant homology to the dipeptide and heme binding protein DppA of Escherichia coli. DppA is a component of the DppABCDF peptide-heme permease of E. coli. H. influenzae homologs of dppBCDF are located in the genome at a point distant from hbpA. The object of this study was to investigate the potential role of the H. influenzae dppBCDF locus in heme utilization. FINDINGS: An insertional mutation in dppC was constructed and the impact of the mutation on the utilization of both free heme and various proteinaceous heme sources as well as utilization of protoporphyrin IX was determined in growth curve studies. The dppC insertion mutant strain was significantly impacted in utilization of all tested heme sources and protoporphyin IX. Complementation of the dppC mutation with an intact dppCBDF gene cluster in trans corrected the growth defects seen in the dppC mutant strain. CONCLUSION: The dppCBDF gene cluster constitutes part of the periplasmic heme-acquisition systems of H. influenzae.

20.
Int J Med Microbiol ; 299(7): 479-88, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19451029

RESUMEN

Haemophilus influenzae has an absolute growth requirement for heme and the heme-binding lipoprotein (HbpA) and has been implicated in the utilization of this essential nutrient. We constructed an insertional mutation of hbpA in a type b and a nontypeable H. influenzae strain. In the type b strain, the hbpA mutant was impaired in utilization of heme complexed to either hemopexin or to albumin and in the utilization of low levels of heme but not in the utilization of heme at high levels or of hemoglobin or hemoglobin-haptoglobin complexes. In contrast, the hbpA mutant derivative of the nontypeable strain was impaired in utilization of all tested heme sources. We further examined the impact of the hbpA mutation in animal models of H. influenzae disease. The hbpA mutant of the nontypeable strain was indistinguishable from the wild-type strain in the chinchilla model of otitis media. The hbpA mutant derivative of the type b strain caused bacteremia as well as the wild-type strain in 5-day old infant rats. However, in 30-day old rats the hbpA caused significantly lower rates of bacteremia than the wild-type strain indicating a role for hbpA and heme acquisition in virulence in this model of H. influenzae disease. In conclusion, HbpA is important for heme utilization by multiple H. influenzae strains and is a virulence determinant in a model of H. influenzae invasive disease.


Asunto(s)
Proteínas Bacterianas/fisiología , Proteínas Portadoras/fisiología , Haemophilus influenzae/patogenicidad , Lipoproteínas/fisiología , Animales , Animales Recién Nacidos , Bacteriemia/microbiología , Proteínas Bacterianas/genética , Proteínas Portadoras/genética , Chinchilla , Modelos Animales de Enfermedad , Femenino , Haemophilus influenzae/genética , Hemo/metabolismo , Humanos , Lipoproteínas/genética , Mutagénesis Insercional , Otitis Media/microbiología , Embarazo , Ratas , Virulencia
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