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1.
Int J Mol Sci ; 23(24)2022 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-36555720

RESUMEN

Establishing the rapid and accurate diagnosis of sepsis is a key component to the improvement of clinical outcomes. The ability of analytical platforms to rapidly detect pathogen-associated molecular patterns (PAMP) in blood could provide a powerful host-independent biomarker of sepsis. A novel concept was investigated based on the idea that a pre-bound and fluorescent ligand could be released from lectins in contact with high-affinity ligands (such as PAMPs). To create fluorescent ligands with precise avidity, the kinetically followed TEMPO oxidation of yeast mannan and carbodiimide coupling were used. The chemical modifications led to decreases in avidity between mannan and human collectins, such as the mannan-binding lectin (MBL) and human surfactant protein D (SP-D), but not in porcine SP-D. Despite this effect, these fluorescent derivatives were captured by human lectins using highly concentrated solutions. The resulting fluorescent beads were exposed to different solutions, and the results showed that displacements occur in contact with higher affinity ligands, proving that two-stage competition processes can occur in collectin carbohydrate recognition mechanisms. Moreover, the fluorescence loss depends on the discrepancy between the respective avidities of the recognized ligand and the fluorescent mannan. Chemically modulated fluorescent ligands associated with a diversity of collectins may lead to the creation of diagnostic tools suitable for multiplex array assays and the identification of high-avidity ligands.


Asunto(s)
Colectinas , Sepsis , Humanos , Animales , Porcinos , Proteína D Asociada a Surfactante Pulmonar/química , Mananos/metabolismo , Ligandos , Lectinas/metabolismo
2.
Infection ; 49(2): 345-348, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32749595

RESUMEN

BACKGROUND: The Bacillus Calmette-Guerin (BCG) is a life-attenuated form of Mycobacterium bovis widely used as immunotherapy for localized bladder cancer. Adverse reactions to intravesical BCG instillations are rare. CASE: We describe a 70-year-old man with a history of an aortobifemoral bypass graft, placement of a synthetic mesh for treatment of a ventral hernia and, most recently, superficial bladder cancer treated with BCG therapy. Ten months after his final intravesical BCG instillation, he complained of fever and asthenia. After 12 months of investigation, he was diagnosed with Mycobacterium bovis infection of his aortobifemoral bypass graft and abdominal mesh, with Streptococcus intermedius superinfection. The bypass graft was excised and replaced with an in situ arterial allograft, the abdominal mesh was removed, and treatment started with amoxicillin, isoniazid, rifampicin and ethambutol. Several additional vascular interventions were needed for allograft degradation, but 12 months after the final procedure, outcome was good. DISCUSSION AND CONCLUSIONS: Among 35 cases of mycotic aneurysm reported after BCG therapy in the last 10 years, only one involved a vascular prosthesis. Surgical repair of such aneurysms using prosthetic grafts is commonly performed, associated with anti-mycobacterial treatment. Prognosis is poor with mortality of 14% (4/35) and a 26% rate of aneurysm recurrence under treatment (9/35).


Asunto(s)
Mycobacterium bovis , Sobreinfección , Neoplasias de la Vejiga Urinaria , Administración Intravesical , Anciano , Vacuna BCG/efectos adversos , Humanos , Inmunoterapia , Masculino , Streptococcus intermedius , Neoplasias de la Vejiga Urinaria/tratamiento farmacológico , Neoplasias de la Vejiga Urinaria/cirugía
3.
Proc Natl Acad Sci U S A ; 115(5): E1002-E1011, 2018 01 30.
Artículo en Inglés | MEDLINE | ID: mdl-29343644

RESUMEN

Mycobacterium abscessus, a rapidly growing mycobacterium (RGM) and an opportunistic human pathogen, is responsible for a wide spectrum of clinical manifestations ranging from pulmonary to skin and soft tissue infections. This intracellular organism can resist the bactericidal defense mechanisms of amoebae and macrophages, an ability that has not been observed in other RGM. M. abscessus can up-regulate several virulence factors during transient infection of amoebae, thereby becoming more virulent in subsequent respiratory infections in mice. Here, we sought to identify the M. abscessus genes required for replication within amoebae. To this end, we constructed and screened a transposon (Tn) insertion library of an M. abscessus subspecies massiliense clinical isolate for attenuated clones. This approach identified five genes within the ESX-4 locus, which in M. abscessus encodes an ESX-4 type VII secretion system that exceptionally also includes the ESX conserved EccE component. To confirm the screening results and to get further insight into the contribution of ESX-4 to M. abscessus growth and survival in amoebae and macrophages, we generated a deletion mutant of eccB4 that encodes a core structural element of ESX-4. This mutant was less efficient at blocking phagosomal acidification than its parental strain. Importantly, and in contrast to the wild-type strain, it also failed to damage phagosomes and showed reduced signs of phagosome-to-cytosol contact, as demonstrated by a combination of cellular and immunological assays. This study attributes an unexpected and genuine biological role to the underexplored mycobacterial ESX-4 system and its substrates.


Asunto(s)
Amoeba/microbiología , Mycobacterium abscessus/patogenicidad , Fagosomas/microbiología , Sistemas de Secreción Tipo IV/genética , Factores de Virulencia/genética , Proteínas Bacterianas/genética , Caspasa 1/metabolismo , Cromatografía en Capa Delgada , Citosol/metabolismo , Activación Enzimática , Citometría de Flujo , Galectina 3/metabolismo , Eliminación de Gen , Genómica , Humanos , Lípidos/química , Macrófagos/microbiología , Mutación , Mycobacterium abscessus/genética , Mycobacterium tuberculosis/patogenicidad , Células THP-1 , Virulencia
4.
Anaerobe ; 72: 102469, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34699978

RESUMEN

OBJECTIVES: Blood culture bottles (BCBs) are commonly used for the diagnosis of infections associated with orthopedic devices. Although Cutibacterium acnes is an important pathogen in orthopedics, relatively little is known about its growth characteristics in BCBs. This prompted us to analyze the influence of bacterial genotype and clinical significance on time-to-detection (TTD) in BCBs. METHODS: We reviewed 59 cases of orthopedic device-related infections in which at least one intraoperative specimen yielded a pure C. acnes culture from anaerobic BCBs (BD Bactec Lytic/10 Anaerobic/F; Lytic-Ana) and/or solid media. A strain was considered infectant if the same genotype was present in two or more intraoperative samples. From these cases, we isolated a total of 72 unique C. acnes strains belonging to four multilocus sequence type clonal complexes (CCs): CC18, CC28, CC36 and CC53. Growth rate and TTD in Lytic-Ana BCB were studied under experimental conditions (inoculation of standard inoculum) and in clinical samples (inoculation of periprosthetic tissue samples). RESULTS: Median TTD values were shorter for CC53 compared to other CCs under experimental conditions (69 vs. 103 h; p < 0.001) and from clinical specimens (70 vs. 200 h; p = 0.02). Infectant strains had a shorter median TTD compared to contaminant strains in a clinical situation, while the difference was not observed under experimental conditions. CONCLUSIONS: The detection dynamics of C. acnes in Lytic-Ana BCBs were associated with genotype. Thus, TTD not only reflects the bacterial load in clinical samples, but may also reflect the intrinsic properties of the clonal complex of C. acnes.


Asunto(s)
Infecciones por Bacterias Grampositivas/diagnóstico , Infecciones por Bacterias Grampositivas/microbiología , Propionibacterium acnes , Infecciones Relacionadas con Prótesis/diagnóstico , Infecciones Relacionadas con Prótesis/etiología , Adulto , Anciano , Proteínas Bacterianas/genética , Técnicas de Tipificación Bacteriana , Cultivo de Sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tipificación de Secuencias Multilocus , Procedimientos Ortopédicos/efectos adversos , Propionibacterium acnes/clasificación , Propionibacterium acnes/genética , Propionibacterium acnes/aislamiento & purificación
5.
BMC Infect Dis ; 20(1): 512, 2020 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-32677896

RESUMEN

BACKGROUND: The aims of this study were to identify the predictive factors for microbiological diagnosis through disco-vertebral biopsy (DVB) in patients with pyogenic vertebral osteomyelitis (PVO) and negative blood cultures, and compare the performance of DVB under fluoroscopic versus scanographic guidance. METHODS: We performed a cohort study comparing positive and negative DVB among patients with PVO. All cases of PVO undergoing a DVB for microbiological diagnosis in our center were retrospectively reviewed. Infections due to Mycobacterium tuberculosis, infections on foreign device, and non-septic diseases were excluded. Anamnestic, clinical, biological, microbiological, as well as radiological data were collected from medical charts thanks to a standardized data set. RESULTS: A total of 111 patients were screened; 88 patients were included. Microbiological cultures were positive in 53/88 (60.2%) patients. A thickening of the paravertebral tissue ≥10 mm on magnetic resonance imaging (MRI) in axial MR scans was a predictive factor of DVB microbiological positivity (52.4% vs. 13.3%; p = 0.006; OR = 5.4). Overall, 51 DVB were performed under fluoroscopic guidance and 37 under scanographic guidance. Considering lumbar DVB, 25/36 (69.4%) of cases yielded positive results under fluoroscopic guidance versus 5/15 (33.3%) under scanographic guidance (p = 0.02; OR = 4.4). No adverse event linked to DVB was notified. CONCLUSION: Every patient with PVO and negative blood cultures should undergo a DVB. A thickening of the paravertebral tissue ≥10 mm on MRI is associated with a higher rate of positive DVB culture. A lumbar DVB under fluoroscopic guidance is more sensitive than under scanographic guidance to identify the micro-organism involved.


Asunto(s)
Disco Intervertebral/patología , Vértebras Lumbares/patología , Osteomielitis/diagnóstico , Enfermedades de la Columna Vertebral/diagnóstico , Infecciones Estafilocócicas/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Absceso Epidural/diagnóstico , Absceso Epidural/patología , Femenino , Fluoroscopía/métodos , Humanos , Biopsia Guiada por Imagen/métodos , Disco Intervertebral/microbiología , Vértebras Lumbares/microbiología , Masculino , Persona de Mediana Edad , Osteomielitis/microbiología , Osteomielitis/patología , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Enfermedades de la Columna Vertebral/microbiología , Enfermedades de la Columna Vertebral/patología , Infecciones Estafilocócicas/patología , Tomografía Computarizada por Rayos X/métodos , Adulto Joven
6.
Clin Orthop Relat Res ; 478(12): 2786-2797, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32667753

RESUMEN

BACKGROUND: Preoperative synovial fluid culture is pivotal in the early diagnosis of prosthetic joint infection (PJI) but may yield false-positive and false-negative results. We evaluated the predictive value of synovial fluid culture results combined with the measurement of serum anti-staphylococcal antibodies (SASA). QUESTIONS/PURPOSES: (1) For hip and knee PJI, does combining positive SASA results with preoperative synovial culture results improve the positive predictive value (PPV) of preoperative synovial fluid culture alone? (2) Does combining preoperative synovial fluid culture results with a positive cell count and differential result increase the PPV of preoperative synovial fluid culture alone? (3) What proportion of isolated organisms exhibit concordance in antibiotic susceptibility: preoperative aspiration versus intraoperative isolates? METHODS: A prospective study was conducted at two French reference centers that manage bone and joint infections and included 481 adult patients who had a revision or resection arthroplasty between June 25, 2012 and June 23, 2014. Exclusion criteria including no serum sample available for immunoassay, the lack of microbiological documentation, and the absence of preoperative aspiration reduced the patient number to 353. Seven patients with an undetermined SASA result were excluded from the analysis. We also excluded patients with PJI involving more than one Staphylococcus species (polystaphylococcal infection) and those in whom more than one Staphylococcus species was recovered from the preoperative synovial fluid culture (polystaphylococcal synovial fluid culture). In total, 340 patients were included in the analysis (no infection, 67% [226 of 340]; staphylococcal infection, 21% [71 of 340]; other infection, 13% [43 of 340]). The preoperative synovial fluid analysis included a cell count and differential and bacterial culture. SASAs were measured using a multiplex immunoassay. The diagnosis of PJI was determined using the Infectious Diseases Society of America (IDSA) criteria [] and intraoperative tissue culture at the time of revision surgery was used as the gold standard (at least one positive intraoperative sample for a "virulent" organism (such as S. aureus) or two positive samples for a "non-virulent" (for example S. epidermidis). RESULTS: SASA increased the PPV compared with synovial fluid culture alone (92% [95% CI 82 to 97] versus 79% [95% CI 68 to 87]; p = 0.04); when stratified by site, an increase in PPV was seen in hip infections (100% [95% CI 89 to 100] versus 77% [95% CI 63 to 88]; p = 0.01) but not in knee infections (84% [95% CI 66 to 95] versus 80% [95% CI 64 to 91]; p = 0.75). A positive cell count and differential result increased the PPV of staphylococcal synovial fluid cultures compared with synovial fluid culture alone (86% [95% CI 70 to 95] versus 79% [95% CI 68 to 87]; p = 0.36); when stratified by site, no difference in hip and knee infections was observed (86% [95% CI 67 to 96] versus 77% [95% CI 63 to 88]; p = 0.42) and 86% [95% CI 70 to 95] versus 80% [95% CI 64 to 91]; p = 0.74). CONCLUSION: SASA measurement improves the predictive value of synovial fluid cultures of the hip for all staphylococcal organisms, including coagulase-negative staphylococci, but the PPV of SASA plus synovial fluid culture it is not superior to the PPV of synovial fluid cell count/differential plus synovial culture for the knee. LEVEL OF EVIDENCE: Level III, diagnostic study.


Asunto(s)
Anticuerpos Antibacterianos/sangre , Artroplastia de Reemplazo de Cadera/efectos adversos , Prótesis de Cadera/efectos adversos , Infecciones Relacionadas con Prótesis/diagnóstico , Pruebas Serológicas , Infecciones Estafilocócicas/diagnóstico , Staphylococcus/inmunología , Líquido Sinovial/microbiología , Anciano , Artroplastia de Reemplazo de Cadera/instrumentación , Artroplastia de Reemplazo de Rodilla/efectos adversos , Artroplastia de Reemplazo de Rodilla/instrumentación , Biomarcadores/sangre , Femenino , Francia , Humanos , Prótesis de la Rodilla/efectos adversos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Cuidados Preoperatorios , Estudios Prospectivos , Infecciones Relacionadas con Prótesis/sangre , Infecciones Relacionadas con Prótesis/microbiología , Infecciones Relacionadas con Prótesis/cirugía , Reproducibilidad de los Resultados , Infecciones Estafilocócicas/sangre , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/cirugía , Succión
7.
Clin Infect Dis ; 68(11): 1942-1945, 2019 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-31098616

RESUMEN

Cutibacterium acnes orthopedic device-related infections (ODRIs) range from obvious infections to solely culture-based diagnoses. Multilocus sequence typing of multiple isolates from the same procedure revealed that most cases with normal C-reactive protein levels that were classified as C. acnes ODRI would be considered contaminations when accounting for genotypic data.


Asunto(s)
Contaminación de Equipos , Infecciones por Bacterias Grampositivas/diagnóstico , Infecciones por Bacterias Grampositivas/microbiología , Tipificación de Secuencias Multilocus , Propionibacterium acnes/clasificación , Adulto , Anciano , Técnicas de Tipificación Bacteriana , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Propionibacterium acnes/aislamiento & purificación
8.
Emerg Infect Dis ; 25(3): 589-592, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30789329

RESUMEN

During June 2017-April 2018, active tuberculosis with Beijing SIT1 isolates was diagnosed in 14 persons living in 4 distant cities in France. Whole-genome sequencing indicated that these patients belonged to a single transmission chain. Whole-genome sequencing-based laboratory investigations enabled prompt tracing of linked cases to improve tuberculosis control.


Asunto(s)
Brotes de Enfermedades , Genoma Bacteriano , Mycobacterium tuberculosis/genética , Tuberculosis/epidemiología , Tuberculosis/microbiología , Secuenciación Completa del Genoma , Francia/epidemiología , Historia del Siglo XXI , Humanos , Mycobacterium tuberculosis/clasificación , Polimorfismo de Nucleótido Simple , Vigilancia de la Población , Tuberculosis/historia
9.
Eur J Clin Microbiol Infect Dis ; 38(7): 1269-1278, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30903537

RESUMEN

Corynebacterium striatum is a ubiquitous colonizer of human skin and mucous membranes. It is increasingly involved in infections, especially with prosthetic devices or in immunocompromised individuals. Microbiological diagnosis is challenging and bacterial resistance is a major concern. We performed a retrospective study of monomicrobial bone and joint infections (BJI) due to C. striatum in two referral centers from April 2012 to July 2017. We collected the patients' clinical and microbiological characteristics and outcomes. We also performed a literature review of BJI due to C. striatum. We identified 12 cases (nine prosthetic joint infections, one osteosynthetic device infection, one non-union, and one arthritis) in 11 patients, five of which were immunocompromised. Microbiological diagnosis was performed with prolonged culture media. Ten out of 12 strains were susceptible to aminopenicillin, a drug class not recommended for testing by the EUCAST/CASFM guidelines, and 8/12 patients were treated with amoxicillin-rifampicin. The cure rate was 8/12, after a median follow-up period of 487.5 days (IQR 140.3-1348.5). Twelve cases of BJI due to C. striatum were previously reported. Among them, 5/12 patients were immunocompromised, 3/12 cases were acute BJI, and 2/12 were device-related infections. The diagnosis was performed by PCR in one case, and 10/12 patients were treated with glycolipopeptides, with a cure rate of 11/12. We report the largest cohort of monomicrobial BJI with C. striatum. Determination of aminopenicillin susceptibility is essential since it is frequently active in our experience, even in BJI. The cure rate of this infection seems high.


Asunto(s)
Amoxicilina/uso terapéutico , Antibacterianos/uso terapéutico , Artritis Infecciosa/tratamiento farmacológico , Enfermedades Óseas Infecciosas/tratamiento farmacológico , Infecciones por Corynebacterium/tratamiento farmacológico , Infecciones Relacionadas con Prótesis/tratamiento farmacológico , Rifampin/uso terapéutico , Anciano , Anciano de 80 o más Años , Artritis Infecciosa/microbiología , Enfermedades Óseas Infecciosas/microbiología , Corynebacterium/efectos de los fármacos , Corynebacterium/aislamiento & purificación , Infecciones por Corynebacterium/diagnóstico , Farmacorresistencia Bacteriana Múltiple , Femenino , Humanos , Huésped Inmunocomprometido , Articulaciones/microbiología , Masculino , Persona de Mediana Edad , Infecciones Relacionadas con Prótesis/microbiología , Estudios Retrospectivos
10.
BMC Genomics ; 17: 118, 2016 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-26884275

RESUMEN

BACKGROUND: In mycobacteria, conjugation differs from the canonical Hfr model, but is still poorly understood. Here, we quantified this evolutionary processe in a natural mycobacterial population, taking advantage of a large clinical strain collection of the emerging pathogen Mycobacterium abscessus (MAB). RESULTS: Multilocus sequence typing confirmed the existence of three M. abscessus subspecies, and unravelled extensive allelic exchange between them. Furthermore, an asymmetrical gene flow occurring between these main lineages was detected, resulting in highly admixed strains. Intriguingly, these mosaic strains were significantly associated with cystic fibrosis patients with lung infections or chronic colonization. Genome sequencing of those hybrid strains confirmed that half of their genomic content was remodelled in large genomic blocks, leading to original tri-modal 'patchwork' architecture. One of these hybrid strains acquired a locus conferring inducible macrolide resistance, and a large genomic insertion from a slowly growing pathogenic mycobacteria, suggesting an adaptive gene transfer. This atypical genomic architecture of the highly recombinogenic strains is consistent with the distributive conjugal transfer (DCT) observed in M. smegmatis. Intriguingly, no known DCT function was found in M. abscessus chromosome, however, a p-RAW-like genetic element was detected in one of the highly admixed strains. CONCLUSION: Taken together, our results strongly suggest that MAB evolution is sporadically punctuated by dramatic genome wide remodelling events. These findings might have far reaching epidemiological consequences for emerging mycobacterial pathogens survey in the context of increasing numbers of rapidly growing mycobacteria and M. tuberculosis co-infections.


Asunto(s)
Evolución Molecular , Genoma Bacteriano , Mosaicismo , Mycobacterium/genética , Técnicas de Tipificación Bacteriana , Hibridación Genómica Comparativa , Conjugación Genética , ADN Bacteriano/genética , Flujo Génico , Frecuencia de los Genes , Transferencia de Gen Horizontal , Humanos , Modelos Genéticos , Tipificación de Secuencias Multilocus , Filogenia , Análisis de Secuencia de ADN
11.
J Clin Microbiol ; 54(4): 1065-73, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26865683

RESUMEN

We developed and evaluated a multiplex antibody detection-based immunoassay for the diagnosis of prosthetic joint infections (PJIs). Sixteen protein antigens from three Staphylococcusspecies (Staphylococcus aureus,Staphylococcus epidermidis, and Staphylococcus lugdunensis) (8 antigens),Streptococcus agalactiae(4 antigens), and Propionibacterium acnes(4 antigens) were selected by comparative immune proteomics using serum samples from PJI cases versus controls. A bead-based multiplex immunoassay that measured serum IgG against purified, recombinant forms of each of the 16 antigens was developed. We conducted a prospective study to evaluate the performance of the assay. A PJI was defined by the presence of a sinus tract and/or positive intraoperative sample cultures (at least one sample yielding a virulent organism or at least two samples yielding the same organism). A total of 455 consecutive patients undergoing revision or resection arthroplasty (hip, 66.3%; knee, 29.7%; shoulder, 4%) at two French reference centers for the management of PJI were included: 176 patients (38.7%) were infected and 279 (61.3%) were not. About 60% of the infections involved at least one of the species targeted by the assay. The sensitivity/specificity values were 72.3%/80.7% for targeted staphylococci, 75%/92.6% forS. agalactiae, and 38.5%/84.8% forP. acnes The assay was more sensitive for infections occurring >3 months after arthroplasty and for patients with an elevated C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR). However, it detected 64.3% and 58.3% of targeted staphylococcal infections associated with normal CRP and ESR values, respectively. This new multiplex immunoassay approach is a novel noninvasive tool to evaluate patients suspected of having PJIs and provides information complementary to that from inflammatory marker values.


Asunto(s)
Anticuerpos Antibacterianos/sangre , Artritis Infecciosa/diagnóstico , Infecciones Bacterianas/diagnóstico , Infecciones Relacionadas con Prótesis/diagnóstico , Pruebas Serológicas/métodos , Anciano , Anciano de 80 o más Años , Antígenos Bacterianos/inmunología , Femenino , Francia , Humanos , Inmunoglobulina G/sangre , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Proteínas Recombinantes/inmunología , Sensibilidad y Especificidad
12.
Infect Immun ; 83(2): 780-91, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25486995

RESUMEN

Mycobacterium abscessus is a pathogenic, rapidly growing mycobacterium involved in pulmonary and cutaneo-mucous infections worldwide, to which cystic fibrosis patients are exquisitely susceptible. The analysis of the genome sequence of M. abscessus showed that this bacterium is endowed with the metabolic pathways typically found in environmental microorganisms that come into contact with soil, plants, and aquatic environments, where free-living amoebae are frequently present. M. abscessus also contains several genes that are characteristically found only in pathogenic bacteria. One of them is MAB_0555, encoding a putative phospholipase C (PLC) that is absent from most other rapidly growing mycobacteria, including Mycobacterium chelonae and Mycobacterium smegmatis. Here, we report that purified recombinant M. abscessus PLC is highly cytotoxic to mouse macrophages, presumably due to hydrolysis of membrane phospholipids. We further showed by constructing and using an M. abscessus PLC knockout mutant that loss of PLC activity is deleterious to M. abscessus intracellular survival in amoebae. The importance of PLC is further supported by the fact that M. abscessus PLC was found to be expressed only in amoebae. Aerosol challenge of mice with M. abscessus strains that were precultured in amoebae enhanced M. abscessus lung infectivity relative to M. abscessus grown in broth culture. Our study underlines the importance of PLC for the virulence of M. abscessus. Despite the difficulties of isolating M. abscessus from environmental sources, our findings suggest that M. abscessus has evolved in close contact with environmental protozoa, which supports the argument that amoebae may contribute to the virulence of opportunistic mycobacteria.


Asunto(s)
Amoeba/fisiología , Infecciones por Mycobacterium no Tuberculosas/inmunología , Mycobacterium/patogenicidad , Fosfolipasas de Tipo C/fisiología , Amoeba/microbiología , Animales , Secuencia de Bases , Células Cultivadas , Técnicas de Cocultivo , Fibrosis Quística/microbiología , Técnicas de Inactivación de Genes , Genoma Bacteriano/genética , Macrófagos/inmunología , Lípidos de la Membrana/metabolismo , Ratones , Ratones Endogámicos BALB C , Mycobacterium/enzimología , Mycobacterium/genética , Infecciones por Mycobacterium no Tuberculosas/microbiología , Proteínas Recombinantes , Análisis de Secuencia de ADN , Fosfolipasas de Tipo C/genética , Factores de Virulencia/genética
13.
J Clin Microbiol ; 53(6): 1955-8, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25878336

RESUMEN

We compared two walk-away molecular diagnostic assays, the GeneXpert MRSA Gen 3 assay and the BD-Max MRSA XT assay. A total of 119 prospective swabs and 36 culture-positive samples were tested. Xpert MRSA Gen 3 had sensitivity of 95.7% and specificity of 100% versus 87.5% and 97.1% for BD-Max. The difference in agreement with the enriched culture results was significantly in favor of the Xpert assay (P < 0.02, McNemar nonparametric text).


Asunto(s)
Staphylococcus aureus Resistente a Meticilina/genética , Técnicas de Diagnóstico Molecular/métodos , Reacción en Cadena de la Polimerasa/métodos , Infecciones Estafilocócicas/diagnóstico , Humanos , Cavidad Nasal/microbiología , Estudios Prospectivos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Infecciones Estafilocócicas/microbiología
15.
Mol Microbiol ; 90(3): 612-29, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23998761

RESUMEN

Mycobacterium abscessus is an emerging pathogen that is increasingly recognized as a relevant cause of human lung infection in cystic fibrosis patients. This highly antibiotic-resistant mycobacterium is an exception within the rapidly growing mycobacteria, which are mainly saprophytic and non-pathogenic organisms. M. abscessus manifests as either a smooth (S) or a rough (R) colony morphotype, which is of clinical importance as R morphotypes are associated with more severe and persistent infections. To better understand the molecular mechanisms behind the S/R alterations, we analysed S and R variants of three isogenic M. abscessus S/R pairs using an unbiased approach involving genome and transcriptome analyses, transcriptional fusions and integrating constructs. This revealed different small insertions, deletions (indels) or single nucleotide polymorphisms within the non-ribosomal peptide synthase gene cluster mps1-mps2-gap or mmpl4b in the three R variants, consistent with the transcriptional differences identified within this genomic locus that is implicated in the synthesis and transport of Glyco-Peptido-Lipids (GPL). In contrast to previous reports, the identification of clearly defined genetic lesions responsible for the loss of GPL-production or transport makes a frequent switching back-and-forth between smooth and rough morphologies in M. abscessus highly unlikely, which is important for our understanding of persistent M. abscessus infections.


Asunto(s)
Genes Bacterianos , Lípidos/biosíntesis , Infecciones por Mycobacterium no Tuberculosas/microbiología , Mycobacterium/genética , Péptido Sintasas/genética , Proteínas Bacterianas/genética , Secuencia de Bases , Perfilación de la Expresión Génica , Variación Genética , Genoma Bacteriano , Humanos , Mutación INDEL , Datos de Secuencia Molecular , Familia de Multigenes , Mycobacterium/clasificación , Mycobacterium/patogenicidad , Polimorfismo de Nucleótido Simple
16.
Orthop Traumatol Surg Res ; : 103881, 2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38582223

RESUMEN

INTRODUCTION: Similar to the management of periprosthetic joint infections of the lower limb, one-stage revision in total shoulder arthroplasty (TSA) infections is an option that has been highlighted in scientific publications since the early 2010s. However, there are only a few studies which validate this treatment and determine its scope of application in relation to two-stage treatment. HYPOTHESIS: Single-stage revision for infected TSA is a reliable treatment allowing good infection control and satisfactory functional results. METHODS: This single-center retrospective series of 34 consecutive patients operated on between 2014 and 2020 for a one-stage prosthetic revision was evaluated at a minimum of 2 years of follow-up. All of the patients included underwent revision shoulder arthroplasty during this period with the diagnosis of infection confirmed by microbiological analysis of surgical samples. Patients who did not benefit from a bipolar revision were excluded. All patients were followed at least 2 years after the intervention. Clinically suspected recurrence of infection was confirmed by a periprosthetic sample under radiographic guidance. Functional clinical outcomes as well as mechanical complications were also reported. RESULTS: The average follow-up was 40.4 months (24-102±21.6). A septic recurrence was observed in three patients (8.8%). A mechanical complication was present in four patients (14.7%), and three (11.8%) required at least one surgical revision. The mean Constant-Murley score at the last follow-up was 49 (42-57±21.83). DISCUSSION: Single-stage revision for shoulder periprosthetic joint infection results in a success rate of 91.2% with satisfactory functional results after more than 2 years of follow-up. LEVEL OF EVIDENCE: IV; retrospective study.

17.
Clin Microbiol Infect ; 30(7): 905-910, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38522842

RESUMEN

OBJECTIVES: To assess the performance of the rapid syndromic BioFire® Joint Infection Panel (BF-JIP) to detect bacterial and fungal pathogens, as well as antibiotic resistance genes, directly in synovial fluid specimens collected from patients with acute arthritis. METHODS: The study was conducted in six French bacteriological laboratories. To assess the performances of BF-JIP, results were compared with those of synovial fluid 14-day culture and, in case of discrepancy, with those of complementary molecular methods and intraoperative samples. A total of 308 synovial fluid specimens were tested after collection from 308 adults and children presenting with clinical and biological suspicion of acute arthritis; patients presenting with acute periprosthetic joint infection were included according to the European Bone and Joint Infection Society 2021 criteria. RESULTS: Only one specimen failed (no result). On the basis of the consolidated data, the BF-JIP was concordant with the 14-day culture in 280 (91.2%) of the 307 specimens finally included in the study. The positive percentage agreement was 84.9% (95% CI, 78.8-89.8%) and the negative percentage agreement was 100% (95% CI, 97.2-100%). The positive predictive value was extremely high (100%; 95% CI, 97.6-100%), whereas the negative predictive value was lower (82.6%; 95% CI, 75.7-88.2%), partially explained by the missing target species in the panel. DISCUSSION: The BF-JIP showed high performances to detect pathogens involved in acute arthritis.


Asunto(s)
Artritis Infecciosa , Bacterias , Líquido Sinovial , Humanos , Estudios Prospectivos , Masculino , Femenino , Anciano , Persona de Mediana Edad , Artritis Infecciosa/microbiología , Artritis Infecciosa/diagnóstico , Adulto , Niño , Bacterias/aislamiento & purificación , Bacterias/clasificación , Bacterias/genética , Líquido Sinovial/microbiología , Anciano de 80 o más Años , Francia , Hongos/aislamiento & purificación , Hongos/clasificación , Hongos/genética , Adolescente , Adulto Joven , Preescolar , Enfermedad Aguda , Infecciones Relacionadas con Prótesis/microbiología , Infecciones Relacionadas con Prótesis/diagnóstico , Sensibilidad y Especificidad , Artritis/microbiología , Artritis/diagnóstico
18.
Int J Infect Dis ; 146: 107122, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38823623

RESUMEN

OBJECTIVES: Nontuberculous mycobacteria (NTM) bone and joint infections (BJIs) are uncommon. We evaluated the characteristics of BJIs and identified differences according to immune status. METHODS: We performed a multicenter retrospective study in France involving patients with documented NTM BJI over a 9-year period. We collected the clinical and microbiological characteristics, management, and clinical outcomes of the patients. RESULTS: Overall, 95 patients were included, of whom 50.5% (48/95) were immunosuppressed. Tenosynovitis was more frequent in the immunocompetent group, and native arthritis more common in the immunosuppressed group. Mycobacerium marinum and M. abscessus complex were significantly more frequent in the immunocompetent group, and M. avium and M. xenopi were significantly more frequent in the immunosuppressed group. The combination of antibiotherapy with surgery tended to be more frequent in the immunocompetent than the immunosuppressed group (63.8% (30/47) vs 47.8% (22/46), respectively); of the latter, 45.7% (21/46) received antimicrobial therapy alone, a higher frequency than in the immunocompetent group (23.4%, 11/47). The median duration of antimicrobial treatment was similar in the two groups (11 months). Mortality was significantly higher in the immunosuppressed group. CONCLUSIONS: Although the clinical presentations and the NTM species involved in BJI differed according to immune status, most recovered completely after treatment.

19.
Clin Microbiol Infect ; 30(7): 937-944, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38556212

RESUMEN

OBJECTIVES: We aimed to describe features and outcomes of cryptococcosis among HIV-seronegative individuals in a large surveillance network for cryptococcosis in France. METHODS: We included incident cases of cryptococcosis in HIV-seronegative individuals from 2005 to 2020. We compared patient characteristics, disease presentations, cryptococcal antigen results, and induction antifungal treatments according to underlying disease. We examined factors associated with 90-day mortality. Among patients with disseminated infections, we investigated whether receipt of flucytosine and polyene combination was associated with lower mortality. RESULTS: Among 652 individuals, 209 (32.1%) had malignancy, 130 (19.9%) were solid-organ transplant recipients, 204 (31.3%) had other immunocompromising conditions, and 109 (16.7%) had no reported underlying factor. The commonest presentations were disseminated infections (63.3%, 413/652) and isolated pulmonary infections (25.3%, 165/652). Solid-organ transplant patients were most likely to have disseminated infections and a positive serum cryptococcal antigen result. Patients with malignancy were older and less likely to receive a flucytosine-containing regimen for disseminated infections than others (58.7%, 78/133 vs. 73.2%, 194/265; p 0.029). The crude 90-day case-fatality ratio was 27.2% (95% CI, 23.5%-31.1%). Age ≥60 years (aOR: 2.75 [1.78-4.26]; p < 0.001), meningitis/fungaemia (aOR: 4.79 [1.80-12.7]; p 0.002), and malignancy (aOR: 2.4 [1.14-5.07]; p 0.02) were associated with higher 90-day mortality. Receipt of flucytosine and polyene combination was associated with lower 90-day mortality (aOR: 0.40 [0.23-0.71]; p 0.002) in multivariable analysis and inverse probability of treatment weighted analysis (aOR: 0.45 [0.25-0.80]; p 0.006). DISCUSSION: HIV-seronegative individuals with cryptococcosis comprise a wide range of underlying conditions with different presentations and outcomes, requiring a tailored approach to diagnosis and management.


Asunto(s)
Antifúngicos , Criptococosis , Humanos , Francia/epidemiología , Femenino , Masculino , Criptococosis/epidemiología , Criptococosis/mortalidad , Persona de Mediana Edad , Adulto , Estudios Transversales , Antifúngicos/uso terapéutico , Anciano , Flucitosina/uso terapéutico , Seronegatividad para VIH , Polienos/uso terapéutico , Adulto Joven , Huésped Inmunocomprometido
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