RESUMEN
The number of antibiotic-resistant bacteria is increasing worldwide, and the demand for novel antimicrobials is constantly growing. Antimicrobial peptides (AMPs) could be an important part of future treatment strategies of various bacterial infection diseases. However, AMPs have relatively low stability, because of proteolytic and chemical degradation. As a consequence, carrier systems protecting the AMPs are greatly needed, to achieve efficient treatments. In addition, the carrier system also must administrate the peptide in a controlled manner to match the therapeutic dose window. In this work, lyotropic liquid crystalline (LC) structures consisting of cubic glycerol monooleate/water and hexagonal glycerol monooleate/oleic acid/water have been examined as carriers for AMPs. These LC structures have the capability of solubilizing both hydrophilic and hydrophobic substances, as well as being biocompatible and biodegradable. Both bulk gels and discrete dispersed structures (i.e., cubosomes and hexosomes) have been studied. Three AMPs have been investigated with respect to phase stability of the LC structures and antimicrobial effect: AP114, DPK-060, and LL-37. Characterization of the LC structures was performed using small-angle X-ray scattering (SAXS), dynamic light scattering, ζ-potential, and cryogenic transmission electron microscopy (Cryo-TEM) and peptide loading efficacy by ultra performance liquid chromatography. The antimicrobial effect of the LCNPs was investigated in vitro using minimum inhibitory concentration (MIC) and time-kill assay. The most hydrophobic peptide (AP114) was shown to induce an increase in negative curvature of the cubic LC system. The most polar peptide (DPK-060) induced a decrease in negative curvature while LL-37 did not change the LC phase at all. The hexagonal LC phase was not affected by any of the AMPs. Moreover, cubosomes loaded with peptides AP114 and DPK-060 showed preserved antimicrobial activity, whereas particles loaded with peptide LL-37 displayed a loss in its broad-spectrum bactericidal properties. AMP-loaded hexosomes showed a reduction in antimicrobial activity.
Asunto(s)
Péptidos Catiónicos Antimicrobianos/química , Péptidos Catiónicos Antimicrobianos/farmacología , Bacterias/efectos de los fármacos , Portadores de Fármacos/química , Lípidos/química , Cristales Líquidos/química , Pruebas de Sensibilidad MicrobianaRESUMEN
The presence of Acinetobacter baumannii outside hospitals is still a controversial issue. The objective of our study was to explore the extrahospital epidemiology of A. baumannii in Lebanon. From February 2012 to October 2013, a total of 73 water samples, 51 soil samples, 37 raw cow milk samples, 50 cow meat samples, 7 raw cheese samples, and 379 animal samples were analyzed by cultural methods for the presence of A. baumannii. Species identification was performed by rpoB gene sequencing. Antibiotic susceptibility was investigated, and the A. baumannii population was studied by two genotyping approaches: multilocus sequence typing (MLST) and blaOXA-51 sequence-based typing (SBT). A. baumannii was detected in 6.9% of water samples, 2.7% of milk samples, 8.0% of meat samples, 14.3% of cheese samples, and 7.7% of animal samples. All isolates showed a susceptible phenotype against most of the antibiotics tested and lacked carbapenemase-encoding genes, except one that harbored a blaOXA-143 gene. MLST analysis revealed the presence of 36 sequence types (STs), among which 24 were novel STs reported for the first time in this study. blaOXA-51 SBT showed the presence of 34 variants, among which 21 were novel and all were isolated from animal origins. Finally, 30 isolates had new partial rpoB sequences and were considered putative new Acinetobacter species. In conclusion, animals can be a potential reservoir for A. baumannii and the dissemination of new emerging carbapenemases. The roles of the novel animal clones identified in community-acquired infections should be investigated.
Asunto(s)
Infecciones por Acinetobacter/veterinaria , Acinetobacter baumannii/aislamiento & purificación , Microbiología de Alimentos , Microbiología del Suelo , Microbiología del Agua , Infecciones por Acinetobacter/epidemiología , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/clasificación , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/genética , Animales , Antibacterianos/farmacología , Bovinos , ADN Bacteriano/química , ADN Bacteriano/genética , ARN Polimerasas Dirigidas por ADN/genética , Genotipo , Líbano/epidemiología , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Tipificación Molecular , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: A. baumannii has emerged as an important nosocomial pathogen with an outstanding ability to acquire multidrug resistant mechanisms. In this study, we investigate the molecular epidemiology and carbapenem resistance mechanisms of A. baumannii in Tripoli, Northern Lebanon. METHODS: One hundred sixteen non-duplicate isolates isolated between 2011 and 2013 in different hospitals in Tripoli, Lebanon from Lebanese patients and wounded Syrian patients during Syrian war were studied. Antibiotic susceptibility testing was determined by agar disc diffusion and Etest. Carbapenemase-encoding genes were investigated by PCR. All isolates were typed by bla OXA-51-like sequence based typing (SBT) and 57 isolates were also analysed by MLST using Pasteur's scheme followed by eBURST analysis. RESULTS: Of the 116 isolates, 70 (60 %) showed a carbapenem resistance phenotype. The bla OXA-23 with an upstream insertion of ISAba1 was the major carbapenem resistance mechanism and detected in 65 isolates. Five isolates, including four from wounded Syrian patients and one from a Lebanese patient, were positive for bla NDM-1. bla OXA-51-like SBT revealed the presence of 14 variants, where bla OXA-66 was the most common and present in 73 isolates, followed by bla OXA-69 in 20 isolates. MLST analysis identified 17 sequence types (ST) and showed a concordance with bla OXA-51-like SBT. Each clonal complex (CC) had a specific bla OXA-51-like sequence such as CC2, which harboured bla OXA-66 variant, and CC1 harbouring bla OXA-69 variant. NDM-1 producing isolates belonged to ST85 (4 Syrian isolates) and ST25 (1 Lebanese isolate). CONCLUSIONS: Our results showed a successful predominance of international clone 2 with a widespread occurrence of OXA-23 carbapenemase in Lebanese hospitals. These findings emphasise the urgent need of effective measures to control the spread of A. baumannii in this country.
Asunto(s)
Infecciones por Acinetobacter/epidemiología , Acinetobacter baumannii/clasificación , Acinetobacter baumannii/genética , Variación Genética , Tipificación Molecular , beta-Lactamasas/genética , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/enzimología , Acinetobacter baumannii/aislamiento & purificación , Infección Hospitalaria/epidemiología , Infección Hospitalaria/microbiología , Genotipo , Hospitales , Humanos , Líbano/epidemiología , Pruebas de Sensibilidad Microbiana , Epidemiología Molecular , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADNRESUMEN
We describe the first case of Pseudoclavibacter species endocarditis in a 44-year-old patient. This genus, rarely isolated from humans, confirms here its role as a human pathogen.
Asunto(s)
Infecciones por Actinomycetales/diagnóstico , Actinomycetales/aislamiento & purificación , Endocarditis Bacteriana/diagnóstico , Actinomycetales/clasificación , Infecciones por Actinomycetales/microbiología , Adulto , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Endocarditis Bacteriana/microbiología , Humanos , Masculino , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
The aim of this study was to unravel, by focusing on cell surface properties, the underlying virulence factors contributing to the difference in the pathogenicity observed in two Acinetobacter baumannii strains isolated from the same patient. The two strains were phenotypically different: (i) a mucoid strain (AB-M), highly virulent in a mouse model of pneumonia, and (ii) a nonmucoid strain (AB-NM), moderately virulent in the same model. The study of the cell surface properties included the microbial adhesion to solvents method, the measurement of the electrophoretic mobility of bacteria, the analysis of biofilm formation by calcofluor white staining, the adherence to silicone catheters, and scanning electron microscopy. The AB-NM strain was more hydrophobic, more adherent to silicone catheters, and produced more biofilm than the AB-M strain. Scanning electron microscopy showed bacterial cells with a rough surface and the formation of large cell clusters for AB-NM whereas the AB-M strain had a smooth surface and formed only a few cell clusters. Contrary to the results of most previous studies, cell surface properties were not correlated to the virulence described in our experimental model, indicating that mechanisms other than adherence may be involved in the expression of A. baumannii virulence.
Asunto(s)
Acinetobacter baumannii/metabolismo , Acinetobacter baumannii/patogenicidad , Virulencia/fisiología , Acinetobacter baumannii/aislamiento & purificación , Acinetobacter baumannii/ultraestructura , Animales , Adhesión Bacteriana , Cápsulas Bacterianas/metabolismo , Cápsulas Bacterianas/ultraestructura , Biopelículas , Catéteres/microbiología , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Ratones , Microscopía Electrónica de Rastreo , Propiedades de Superficie , Factores de Virulencia/metabolismoRESUMEN
A critical feature of Mycobacterium tuberculosis, the causative agent of human tuberculosis (TB), is its ability to survive and multiply within macrophages, making these host cells an ideal niche for persisting microbes. Killing the intracellular tubercle bacilli is a key requirement for efficient tuberculosis treatment, yet identifying potent inhibitors has been hampered by labor-intensive techniques and lack of validated targets. Here, we present the development of a phenotypic cell-based assay that uses automated confocal fluorescence microscopy for high throughput screening of chemicals that interfere with the replication of M. tuberculosis within macrophages. Screening a library of 57,000 small molecules led to the identification of 135 active compounds with potent intracellular anti-mycobacterial efficacy and no host cell toxicity. Among these, the dinitrobenzamide derivatives (DNB) showed high activity against M. tuberculosis, including extensively drug resistant (XDR) strains. More importantly, we demonstrate that incubation of M. tuberculosis with DNB inhibited the formation of both lipoarabinomannan and arabinogalactan, attributable to the inhibition of decaprenyl-phospho-arabinose synthesis catalyzed by the decaprenyl-phosphoribose 2' epimerase DprE1/DprE2. Inhibition of this new target will likely contribute to new therapeutic solutions against emerging XDR-TB. Beyond validating the high throughput/content screening approach, our results open new avenues for finding the next generation of antimicrobials.
Asunto(s)
Antibióticos Antituberculosos/farmacología , Descubrimiento de Drogas/métodos , Mycobacterium tuberculosis/efectos de los fármacos , Racemasas y Epimerasas/antagonistas & inhibidores , Animales , Benzamidas/farmacología , Procesos de Crecimiento Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Humanos , Macrófagos/microbiología , Ratones , Pruebas de Sensibilidad Microbiana , Microscopía Confocal/métodos , Microscopía Fluorescente/métodos , Mycobacterium tuberculosis/enzimología , Análisis de Componente Principal , Reproducibilidad de los Resultados , Relación Estructura-Actividad , Tuberculosis/tratamiento farmacológico , Tuberculosis/microbiologíaRESUMEN
AIMS: To assess the impact of a multi-faceted training program on the compliance with hand hygiene and gloving practices. BACKGROUND: Hand hygiene is considered as the cornerstone of the prevention of hospital-acquired infections. Several studies have enhanced the poor effectiveness of training programs in improving hand hygiene compliance. DESIGN: A before-after evaluation study. METHODS: The study was conducted in four healthcare settings before and after an intervention program which included the performance feedback of the first evaluation phase, three six-h training sessions, the assessment of hand hygiene performance with teaching boxes and the organisation of one full-day session devoted to institutional communication around hand hygiene in each setting. Hand hygiene compliance and quality of hand rubbing were evaluated. Hand hygiene opportunities were differentiated into extra-series opportunities (before or after a single contact and before the first contact or after the last contact of a series of consecutive contacts) and intra-series opportunities (from the opportunity following the first contact to the opportunity preceding the last in the same series). RESULTS: Overall, 969 contacts corresponding to 1,470 hand hygiene opportunities (760 during the first phase and 710 during the second) were observed. A significant improvement of observed practices was recorded for the hand hygiene compliance in intra-series opportunities (39·0% vs. 19·0%; p < 10(-5) ), the proportion of gloves worn if indicated (71·4% vs. 52·0%; p < 0·001) and the quality of hand rubbing (85·0% vs. 71·9%; p < 10(-5) ). CONCLUSIONS: Some of the performances measured for both hand hygiene and gloving practices were improved. We plan to extend this investigation by performing a qualitative study with experts in behavioural sciences to try improving practices for which adherence was still weak after the training program such as hand hygiene in intra-series opportunities. RELEVANCE TO CLINICAL PRACTICE: This study underscored the usefulness of implementing contextualised training programs, while more traditional courses have shown little impact.
Asunto(s)
Guantes Protectores , Desinfección de las Manos , Administración de Instituciones de Salud , Higiene , Adhesión a Directriz , HumanosRESUMEN
BACKGROUND: Meropenem is a carbapenem that has an excellent activity against many gram-positive and gram-negative aerobic, facultative, and anaerobic bacteria. The major objective of the present study was to assess the in vitro activity of meropenem compared to imipenem and piperacillin/tazobactam, against 1071 non-repetitive isolates collected from patients with bacteremia (55%), pneumonia (29%), peritonitis (12%) and wound infections (3%), in 15 French hospitals in 2006. The secondary aim of the study was to compare the results of routinely testings and those obtained by a referent laboratory. METHOD: Susceptibility testing and Minimum Inhibitory Concentrations (MICs) of meropenem, imipenem and piperacillin/tazobactam were determined locally by Etest method. Susceptibility to meropenem was confirmed at a central laboratory by disc diffusion method and MICs determined by agar dilution method for meropenem, imipenem and piperacillin/tazobactam. RESULTS: Cumulative susceptibility rates against Escherichia coli were, meropenem and imipenem: 100% and piperacillin/tazobactam: 90%. Against other Enterobacteriaceae, the rates were meropenem: 99%, imipenem: 98% and piperacillin/tazobactam: 90%. All Staphylococci, Streptococci and anaerobes were susceptible to the three antibiotics. Against non fermeters, meropenem was active on 84-94% of the strains, imipenem on 84-98% of the strains and piperacillin/tazobactam on 90-100% of the strains. CONCLUSIONS: Compared to imipenem, meropenem displays lower MICs against Enterobacteriaceae, Escherichia coli and Pseudomonas aeruginosa. Except for non fermenters, MICs90 of carbapenems were <4 mg/L. Piperacillin/tazobactam was less active against Enterobacteriaceae and Acinetobacter but not P. aeruginosa. Some discrepancies were noted between MICs determined by Etest accross centres and MICs determined by agar dilution method at the central laboratory. Discrepancies were more common for imipenem testing and more frequently related to a few centres. Overall MICs determined by Etest were in general higher (0.5 log to 1 log fold) than MICs by agar dilution.
Asunto(s)
Antibacterianos/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Imipenem/farmacología , Tienamicinas/farmacología , Bacteriemia/microbiología , Francia , Bacterias Gramnegativas/aislamiento & purificación , Bacterias Grampositivas/aislamiento & purificación , Humanos , Meropenem , Pruebas de Sensibilidad Microbiana/métodos , Ácido Penicilánico/análogos & derivados , Ácido Penicilánico/farmacología , Peritonitis/microbiología , Piperacilina/farmacología , Combinación Piperacilina y Tazobactam , Neumonía Bacteriana/microbiología , Infección de Heridas/microbiologíaRESUMEN
The SFBC Working Group on critical care testing describes in this paper the SFBC recommendations for the determination of maximal turnaround times (TAT) for laboratory medicine examination in emergency conditions. The table presented in a previous paper was updated, taken into account the clinical situations, as well as the emergency response capabilities of the medical laboratory. These new French recommendations must to be based to each local situation in a clinical-biological context between the physicians and the specialist in Lab Medicine.
Asunto(s)
Cuidados Críticos , Ciencia del Laboratorio Clínico/normas , Pruebas en el Punto de Atención/normas , Práctica Profesional/normas , Acreditación , Cuidados Críticos/clasificación , Cuidados Críticos/métodos , Cuidados Críticos/organización & administración , Cuidados Críticos/normas , Urgencias Médicas/clasificación , Francia , Humanos , Ciencia del Laboratorio Clínico/organización & administración , Sociedades Médicas/normasRESUMEN
Endotoxemia and bacterial infection are frequent in patients with cirrhosis. They alter systemic and splanchnic hemodynamics, worsen coagulation disorders, impair liver function and thus may induce variceal bleeding. In variceal bleeding, bacterial infection favours failure to control bleeding, early rebleeding, and death. In patients with cirrhosis and variceal bleeding, antibiotic-prophylaxis decreases bacterial infection and the incidence of early rebleeding, and, more important, significantly decreases the death rate in these patients.
Asunto(s)
Infecciones Bacterianas/complicaciones , Várices Esofágicas y Gástricas/complicaciones , Hemorragia Gastrointestinal/etiología , Cirrosis Hepática/complicaciones , Antibacterianos/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Várices Esofágicas y Gástricas/tratamiento farmacológico , Hemorragia Gastrointestinal/tratamiento farmacológico , Hemorragia Gastrointestinal/microbiología , Hemorragia Gastrointestinal/prevención & control , Humanos , Cirrosis Hepática/tratamiento farmacológico , Resultado del TratamientoRESUMEN
AIM: Implementing a mouse model of Acinetobacter baumannii (AB) digestive colonization and studying the propensity of an intestinal reservoir of AB to be at the origin of pneumonia. MATERIALS & METHODS: After a disruption of the digestive flora by piperacillin-tazobactam, two multidrug-resistant AB strains were intranasally inoculated to two cohorts of ten mice daily. For each strain, five mice were rendered transiently neutropenic. RESULTS & CONCLUSION: One strain persisted several weeks in the digestive tract, even after stopping piperacillin-tazobactam injections, leading to the hypothesis that some AB strains can authentically colonize the gut. Most of the immunocompromised mice experienced clinical signs and positive lung cultures, which were associated with positive spleen cultures, an argument in favor of bacterial translocation.
Asunto(s)
Infecciones por Acinetobacter/microbiología , Modelos Animales de Enfermedad , Tracto Gastrointestinal/microbiología , Pulmón/microbiología , Neumonía Bacteriana/microbiología , Acinetobacter/aislamiento & purificación , Acinetobacter/fisiología , Animales , Antibacterianos/administración & dosificación , Traslocación Bacteriana , Farmacorresistencia Bacteriana Múltiple , Tracto Gastrointestinal/efectos de los fármacos , Terapia de Inmunosupresión , Ratones , Neutropenia/microbiología , Ácido Penicilánico/administración & dosificación , Ácido Penicilánico/análogos & derivados , Piperacilina/administración & dosificación , Combinación Piperacilina y TazobactamRESUMEN
BACKGROUND: Glycopeptide-intermediate Staphylococcus aureus (GISA) is emerging as a cause of nosocomial infection and outbreaks of infection and colonization in intensive care units (ICUs). We describe an outbreak of GISA colonization/infection and the ensuing control measures in an ICU and investigate outcomes of the affected patients. METHODS: We describe an outbreak of GISA colonization and infection that affected 21 patients in a medical ICU at a tertiary care teaching hospital, as well as the measures taken to eradicate the GISA strain. RESULT: Recognition of the outbreak was difficult. Infections, all of which were severe, were diagnosed in 11 of 21 patients. Patient isolation and barrier precautions failed when used alone. Addition of a stringent policy of restricted admissions, twice daily environmental cleaning, and implementation of hand decontamination with a hydroalcoholic solution led to outbreak termination. This was associated with increases in workload, despite a marked decrease in the number of admissions. CONCLUSION: This first description of a large outbreak of GISA colonization and infection underlines the importance of routine GISA-strain detection when methicillin-resistant S. aureus is isolated. Outbreak control may be difficult to achieve.
Asunto(s)
Brotes de Enfermedades , Farmacorresistencia Bacteriana , Glicopéptidos/farmacología , Control de Infecciones , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/efectos de los fármacos , Antibacterianos/farmacología , Portador Sano , Infección Hospitalaria , Desinfección de las Manos/métodos , Personal de Salud , Servicio de Limpieza en Hospital , Humanos , Control de Infecciones/métodos , Unidades de Cuidados Intensivos , Factores de TiempoRESUMEN
We compared the sensitivity of screening with nasal culture alone with that of a multiple-site screening method for the identification of carriers of methicillin-resistant Staphylococcus aureus at hospital admission. If nasal cultures alone had been used during the 1-year study, 27.0% of carriers of methicillin-resistant S. aureus would have been missed, which corresponds to 560 theoretical isolation days. If rectal screening had not been used, 431 theoretical isolation days would have been missed, and, if axillary screening had not been used, 99 theoretical isolation days would have been missed.
Asunto(s)
Hospitales de Enseñanza , Tamizaje Masivo/métodos , Resistencia a la Meticilina , Admisión del Paciente , Staphylococcus aureus/aislamiento & purificación , Francia , Humanos , Staphylococcus aureus/efectos de los fármacosRESUMEN
BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has become an increasingly important pathogen responsible for hospital-acquired infections. Our study was to evaluate the efficiency of our selective screening program for methicillin-resistant Staphylococcus aureus (MRSA) carriers at admission to nonintensive care units. METHODS: During 6 months, all patients were screened at admission to an internal medicine ward, at which time they were classified as patients at risk of carriage (PRC) and those with no known risk factor. The amplitude of cross transmission was estimated using various indicators during this universal screening period and during the same calendar period of the preceding year (selective screening). RESULTS: The prevalence of MRSA carriage at admission was 5.5%. Among the 22 carriers identified, only 10 were PRC. Age >80 years was significantly associated with MRSA carriage upon admission (OR, 3.5; P < .01). All estimation indicators of MRSA dissemination amplitude were significantly lower during universal screening (relative risks varied from 2.79 to 26.4 according to indicators), demonstrating the need to broaden our criteria defining PRC. CONCLUSION: Adding patients >80 years of age to our PRC definition would increase screening sensitivity (15 carriers identified for 128 patients sampled) and would enable early implementation of barrier precautions for the additional carriers identified.
Asunto(s)
Portador Sano/diagnóstico , Pruebas Diagnósticas de Rutina/métodos , Resistencia a la Meticilina , Infecciones Estafilocócicas/transmisión , Factores de Edad , Anciano , Anciano de 80 o más Años , Portador Sano/epidemiología , Francia/epidemiología , Humanos , Tamizaje Masivo/métodos , Persona de Mediana Edad , Prevalencia , Estudios Prospectivos , Infecciones Estafilocócicas/prevención & controlRESUMEN
Acinetobacter spp. are ubiquitous gram negative and non-fermenting coccobacilli that have the ability to occupy several ecological niches including environment, animals and human. Among the different species, Acinetobacter baumannii has evolved as global pathogen causing wide range of infection. Since the implementation of molecular techniques, the habitat and the role of non-baumannii Acinetobacter in human infection have been elucidated. In addition, several new species have been described. In the present review, we summarize the recent data about the natural reservoir of non-baumannii Acinetobacter including the novel species that have been described for the first time from environmental sources and reported during the last years.
RESUMEN
Acinetobacter baumannii has emerged as a major cause of nosocomial infections. The ability of A. baumannii to display various resistance mechanisms against antibiotics has transformed it into a successful nosocomial pathogen. The limited number of antibiotics in development and the disengagement of the pharmaceutical industry have prompted the development of innovative strategies. One of these strategies is the use of essential oils, especially aromatic compounds that are potent antibacterial molecules. Among them, the combination of carvacrol and cinnamaldehyde has already demonstrated antibacterial efficacy against A. baumannii. The aim of this study was to determine the biological effects of these two compounds in A. baumannii, describing their effect on the rRNA and gene regulation under environmental stress conditions. Results demonstrated rRNA degradation by the carvacrol/cinnamaldehyde mixture, and this effect was due to carvacrol. Degradation was conserved after encapsulation of the mixture in lipid nanocapsules. Results showed an upregulation of the genes coding for heat shock proteins, such as groES, groEL, dnaK, clpB, and the catalase katE, after exposure to carvacrol/cinnamaldehyde mixture. The catalase was upregulated after carvacrol exposure wich is related to an oxidative stress. The combination of thiourea (hydroxyl radical scavenger) and carvacrol demonstrated a potent bactericidal effect. These results underline the development of defense strategies of the bacteria by synthesis of reactive oxygen species in response to environmental stress conditions, such as carvacrol.
RESUMEN
OBJECTIVES: To investigate the molecular epidemiology of Acinetobacter baumannii strains isolated from different hospitals in Lebanon. METHODS: A total of 119 non-duplicate Acinetobacter strains were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and partial rpoB gene sequencing. Antibiotic susceptibility testing was performed by disc diffusion method and all identified carbapenem-resistant isolates were investigated by PCR assays for the presence of the carbapenemase-encoding genes. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were used for molecular typing. RESULTS: Of the 119 A. baumannii isolates, 76.5% were resistant to carbapenems. The most common carbapenemase was the OXA-23-type, found in 82 isolates. The study of population structure using MLST revealed the presence of 30 sequence types (STs) including 18 new ones, with ST2 being the most commonly detected, accounting for 61% of the isolates typed. PFGE performed on all strains of ST2 identified a major cluster of 53 isolates, in addition to three other minor clusters and ten unique profiles. CONCLUSIONS: This study highlights the wide dissemination of highly related OXA-23-producing carbapenem-resistant A. baumannii belonging to the international clone II in Lebanon. Thus, appropriate infection control measures are recommended in order to control the geographical spread of this clone in this country.
Asunto(s)
Infecciones por Acinetobacter/epidemiología , Acinetobacter baumannii/aislamiento & purificación , beta-Lactamasas/metabolismo , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/efectos de los fármacos , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Carbapenémicos/farmacología , Electroforesis en Gel de Campo Pulsado , Hospitales , Humanos , Líbano/epidemiología , Pruebas de Sensibilidad Microbiana , Epidemiología Molecular , Tipificación de Secuencias Multilocus , Reacción en Cadena de la Polimerasa , beta-Lactamasas/genéticaRESUMEN
AIM: To investigate the extrahospital reservoirs of Acinetobacter spp. in Lebanon. MATERIALS & METHODS: Two thousand three hundred and sixty-one samples from different ecological niches were analyzed by culture methods. Species identification was confirmed by rpoB-gene sequencing. Multilocus sequence typing was used to characterize the Acinetobacter baumannii clones. RESULTS & CONCLUSION: Acinetobacter spp. were detected in 14% of environmental samples and 8% of food samples. Furthermore, 9% of animals and 3.4% of humans were colonized. Non-baumannii Acinetobacter were the most common species isolated and newly susceptible A. baumannii clones were detected. Interestingly, 21 isolates were not identified at the species level and were considered as putative novel species. To our knowledge, this is the largest epidemiological study investigating the epidemiology of Acinetobacter spp. outside hospitals.
Asunto(s)
Infecciones por Acinetobacter/microbiología , Infecciones por Acinetobacter/veterinaria , Acinetobacter/aislamiento & purificación , Microbiología Ambiental , Microbiología de Alimentos , Acinetobacter/clasificación , Acinetobacter/efectos de los fármacos , Acinetobacter/genética , Infecciones por Acinetobacter/epidemiología , Adolescente , Adulto , Anciano , Animales , Antibacterianos/farmacología , Biodiversidad , Niño , Preescolar , Femenino , Humanos , Líbano/epidemiología , Ganado/microbiología , Masculino , Persona de Mediana Edad , Tipificación de Secuencias Multilocus , Mascotas/microbiología , Filogenia , Adulto JovenRESUMEN
Lipid nanocapsules (LNCs) are a new generation of biomimetic nanocarriers obtained via a phase inversion temperature method and have an oily core of medium-chain triglycerides that is surrounded by a shelf containing a lipophilic surfactant (lecithin) and a hydrophilic surfactant macrogol 15-hydroxystearate. The aim of the present study was to produce LNCs with antibacterial activity by replacing lecithin with other lipophilic surface active compounds, namely medium-chain fatty acids and their 1-monoglycerides, which are known to have antimicrobial properties. Fatty acids and monoglycerides were found to affect the properties of LNCs, such as particle size and zeta potential. Incorporation of a co-surfactant decreased significantly particle size (p⩽0.0039). Furthermore, incorporation of either lecithin or fatty acids with at least 10 carbon atoms yielded LNCs with the zeta potential significantly more negative than that of LNCs composed solely of triglycerides and macrogol 15 hydroxystearate (p⩽0.0310). Moreover, they were capable of decreasing the phase inversion temperature. The activity of the LCNs against Gram-positive S. aureus, including a methicillin-resistant strain, increased with increases in the length of the hydrocarbon tail. Monoglyceride-LNCs were found to be more active than the corresponding fatty acids. The opposite behaviour was observed for Gram-negative bacteria, whereby only caproic acid- and caprylic acid-LNCs were found to be active against these organisms. The monoglyceride-LNCs were bactericidal, and they killed in a time-dependent manner. Fatty acid-LNCs killed in a concentration-dependent manner. A haemolysis assay was performed to obtain preliminary information on the safety of the tested LNCs. In the case of fatty acid-LNCs, the concentrations at which bacterial growth was inhibited were similar to the haemolytic concentrations. However, monoglyceride-LNCs showed antibacterial action at concentrations much lower than those at which haemolysis was observed. In conclusion, monoglyceride-LNCs are promising candidates as carriers for the encapsulation of antibacterial agents, particularly against S. aureus.
Asunto(s)
Antibacterianos/química , Ácidos Grasos/química , Lípidos/química , Monoglicéridos/química , Nanocápsulas/química , Tensoactivos/química , Animales , Antiinfecciosos/química , Biomimética , Portadores de Fármacos/química , Hemólisis , Caballos , Cinética , Lecitinas/química , Tamaño de la Partícula , Staphylococcus aureus/metabolismo , TemperaturaRESUMEN
SFBC working group on critical care testing describes in this paper guideline for the management of laboratory medicine examination process in emergency conditions. After a summary on French standards and regulations, the critical care testing perimeter and definitions of stat levels are presented in different contexts. The complete examination process is described. Guidelines are proposed for each step, to manage sub-process in a risk management approach. The following steps were studied: ordering (by specialties), sampling, transport, reception, analysis, validation and release. In summary, we proposed a list of examinations allowed to be prescribed in stat conditions with a short list and complementary tests as a function of clinical setting. These guidelines need to be adapted in clinicobiological contracts.