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1.
Eur J Clin Microbiol Infect Dis ; 42(7): 803-818, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37093325

RESUMO

A ring trial among five European laboratories was organized to reach consistency in microsatellite (MS) typing of the zoonotic parasite Toxoplasma gondii. Three sample sets were circulated and analyzed by each laboratory following a previously published method that is based on fragment length polymorphism of 15 MS markers. The first sample set compared typing results in general and focused on effects of DNA concentration; the second sample set focused on the polymorphic fingerprinting markers that can differentiate T. gondii strains within the same archetypal lineage; and the third set focused on non-archetypal genotypes. Methodological variations between laboratories, including the software programs used to determine MS fragment length, were collated using a questionnaire. Overall, lineage-level typing results reached a high level of agreement, especially in samples with the highest DNA concentrations. However, laboratory-specific differences were observed for particular markers. Major median differences in fragment length, of up to 6 base pairs, were related to the fluorophore used to label fragment-specific primers. In addition, primer pairs with identical sequences obtained from different suppliers resulted in fragments of differing length. Furthermore, differences in the way the sequencing profiles were assessed and interpreted may have led to deviating results in fragment length determination. Harmonization of MS typing, for example, by using the same fluorophores or by numerical adjustments applied to the fragment-lengths determined, could improve the uniformity of the results across laboratories. This is the first interlaboratory comparison, providing guidelines (added as a supplement) for the optimization of this technique.


Assuntos
Toxoplasma , Toxoplasmose Animal , Humanos , Animais , Toxoplasma/genética , Variação Genética , Polimorfismo de Fragmento de Restrição , DNA de Protozoário/genética , Repetições de Microssatélites , Genótipo
2.
Gynecol Obstet Fertil Senol ; 50(6): 486-493, 2022 06.
Artigo em Francês | MEDLINE | ID: mdl-35483610

RESUMO

Many countries with a high perinatal level have started a policy of vaccination of pregnant women against pertussis. To date, France has not chosen this policy. The objective was to review knowledge on pertussis mortality in infants. Compare the strategies available to protect the infant before his first vaccination, scheduled for two months of age. We proceeded to a litterature analysis, from January 1998 to 2021. Search by the following keywords used ; "Whooping cough, vaccination, pregnancy, strategy, cocooning", on the scientific basis of "Pubmed", as well as French and foreign vaccination recommendations. Currently 90% of whooping cough deaths are concerning infants under six months of age and this mortality represents 2% of mortality in the first year of life. Vaccination at birth is not effective. The cocooning strategy, which consists of vaccinating those around the child, is expensive and difficult to implement. A systematic vaccination policy for pregnant women is effective and reasonably expensive when compared to the cocooning strategy. In England, it was recently accompanied by a 78% reduction in confirmed cases of pertussis in infants under six months of age. In conclusion, compared to cocooning strategy, pertussis vaccination of pregnant women appears more effective and cost-effective, and this with each pregnancy.


Assuntos
Coqueluche , Criança , Análise Custo-Benefício , Feminino , Humanos , Lactente , Recém-Nascido , Parto , Gravidez , Gestantes , Vacinação , Coqueluche/prevenção & controle
4.
J Hosp Infect ; 118: 48-58, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34492304

RESUMO

Colonization resistance by gut microbiota is a fundamental phenomenon in infection prevention and control. Hospitalized patients may be exposed to multi-drug-resistant bacteria when hand hygiene compliance among healthcare workers is not adequate. An additional layer of defence is provided by the healthy gut microbiota, which helps clear the exogenous bacteria and acts as a safety net when hand hygiene procedures are not followed. This narrative review focuses on the role of the gut microbiota in colonization resistance against multi-drug-resistant bacteria, and its implications for infection control. The review discusses the underlying mechanisms of colonization resistance (direct or indirect), the concept of resilience of the gut microbiota, the link between the antimicrobial spectrum and gut dysbiosis, and possible therapeutic strategies. Antimicrobial stewardship is crucial to maximize the effects of colonization resistance. Avoiding unnecessary antimicrobial therapy, shortening the antimicrobial duration as much as possible, and favouring antibiotics with low anti-anaerobe activity may decrease the acquisition and expansion of multi-drug-resistant bacteria. Even after antimicrobial therapy, the resilience of the gut microbiota often occurs spontaneously. Spontaneous resilience explains the existence of a window of opportunity for colonization of multi-drug-resistant bacteria during or just after antimicrobial therapy. Strategies favouring resilience of the gut microbiota, such as high-fibre diets or precision probiotics, should be evaluated.


Assuntos
Microbioma Gastrointestinal , Preparações Farmacêuticas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana Múltipla , Disbiose , Humanos
5.
Gynecol Obstet Fertil Senol ; 49(7-8): 608-616, 2021.
Artigo em Francês | MEDLINE | ID: mdl-33434747

RESUMO

Chlamydia trachomatis (CT) is the most common sexually transmitted bacterial infection worldwide. It is asymptomatic in most cases and mainly affects young women, with potential long term sequelae (pelvic inflammatory disease, tubal infertility, obstetric complications). The impact on male fertility is controversial. Screening methods as well as antibiotics use have recently been reassessed due to resistance phenomena and the negative effect on the urogenital microbiota. Positive CT serology may be indicative of tuboperitoneal pathology, which may not be noticed on hysterosalpingography. New research on single-nucleotide polymorphisms (SNPs) aims to establish a patient profile at higher risk of infectious tubal damage due to CT. CT seropositivity is also associated with decreased spontaneous pregnancy rates and is a predictive factor for obstetrical complications.


Assuntos
Infecções por Chlamydia , Infertilidade Feminina , Infertilidade , Doença Inflamatória Pélvica , Infecções por Chlamydia/complicações , Infecções por Chlamydia/diagnóstico , Chlamydia trachomatis , Feminino , Humanos , Histerossalpingografia , Infertilidade Feminina/etiologia , Masculino , Gravidez
6.
Int J Obstet Anesth ; 41: 22-28, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31402310

RESUMO

BACKGROUND: Most pregnant women who self-report penicillin allergy are not truly penicillin-allergic and this misunderstanding often leads to administration of inappropriate antibiotic therapy. Decision algorithms have been developed to guide antibiotic selection but major discrepancies have been reported between guidelines and clinical practice. We aimed to optimize the prescription of antibiotics for pregnant women who self-reported penicillin allergy, using an educational intervention about the classification of penicillin allergies that targeted gynecologists, anesthesiologists and midwives. METHODS: This quasi-experimental study assessed the effect of an educational intervention about the classification of penicillin allergy. For six months, a combination of two strategies was used, namely dissemination of printed educational materials and group education. The principal study endpoint was the appropriateness of the antibiotic therapy, defined in advance for each level of allergic risk. RESULTS: The pre-intervention phase included 903 women; one year after its conclusion, the post-intervention phase began and included 892 women. The prevalence of self-reported penicillin allergy was stable over the two periods (6.8% before vs 5.4% after, P=0.24). The clinical classification of penicillin allergies was more often used after the educational intervention (68% vs 100%, P<0.001). The appropriateness of the antibiotic therapy prescribed to self-reported penicillin allergic-women increased significantly between the two periods, from 5/29 (17.2%) to 18/27 (66.7%, P<0.001). CONCLUSION: An educational intervention about penicillin allergy classification was associated with an improvement in the choice of appropriate antibiotic therapy among women who had reported penicillin allergy.


Assuntos
Antibacterianos/efeitos adversos , Hipersensibilidade a Drogas/classificação , Educação de Pacientes como Assunto , Penicilinas/efeitos adversos , Feminino , Humanos , Gravidez , Gestantes
7.
Gynecol Obstet Fertil Senol ; 47(5): 442-450, 2019 05.
Artigo em Francês | MEDLINE | ID: mdl-30890463

RESUMO

Postpartum endometritis accounts for 2% of postpartum infections in developed countries. In France, 2.3% of deaths are attributed to puerperal infections. The most important risk factor is cesarean delivery, especially if it is done after the start of labor. Bacteria of the vaginal microbiota are associated with postpartum endometritis. Symptoms are abdomino-pelvic pain, hyperthermia and abnormal lochia. The diagnosis is confirmed by uterine mobilization pain. The first-line antibiotic therapy is amoxicillin-clavulanic acid 3 to 6 grams per day depending on the weight, intravenously or orally. In case of impossibility to use penicillins (anaphylaxis for example), the combination of clindamycin 600mg×4/d plus gentamicin 5mg/kg×1/d may be use, it must be a specialized decision in case of maternal breastfeeding. The treatment is continued until obtaining 48hours of apyrexia and the disappearance of pelvic pain. In case of persistence of fever and/or pelvic pain after 72hours of antibiotic therapy, pelvic imaging should be performed for placental retention, septic thrombophlebitis, deep abscess or any other surgical complication and eliminate differential diagnoses. It is important to highlight the difficulties of interpreting endo-uterine images in ultrasound. Hypocoagulant heparin therapy should be started in case of septic thrombophlebitis for 6 weeks, or longer if there are complications such as embolism or thrombotic risk factors. Regarding prevention, during a caesarean section, a vaginal swab with iodinated polividone or chlorhexidine is recommended before caesarean if possible, and extraction of the placenta must be spontaneous.


Assuntos
Endometrite , Doença Inflamatória Pélvica , Combinação Amoxicilina e Clavulanato de Potássio/uso terapêutico , Antibacterianos/uso terapêutico , Anticoagulantes/uso terapêutico , Cesárea/efeitos adversos , Endometrite/diagnóstico , Endometrite/tratamento farmacológico , Endometrite/microbiologia , Feminino , Febre , Humanos , Doença Inflamatória Pélvica/diagnóstico , Doença Inflamatória Pélvica/tratamento farmacológico , Doença Inflamatória Pélvica/microbiologia , Dor Pélvica , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/tratamento farmacológico , Gravidez , Infecção Puerperal , Fatores de Risco , Tromboflebite/diagnóstico , Tromboflebite/tratamento farmacológico , Vagina/microbiologia
8.
Gynecol Obstet Fertil Senol ; 47(5): 398-403, 2019 05.
Artigo em Francês | MEDLINE | ID: mdl-30880245

RESUMO

OBJECTIVES: To provide up-to-date guidelines on management of pelvic inflammatory disease (PID). METHODS: An initial search of the Cochrane database, PubMed, and Embase was performed using keywords related to PID to identify reports in any language published between January 1990 and January 2012, with an update in 2018. All identified reports published in French and English relevant to the areas of focus were included. A level of evidence based on the quality of the data available was applied for each area of focus and used for the guidelines. RESULTS: PID must be suspected when spontaneous pelvic pain is associated with induced adnexal or uterine pain (grade B). Pelvic ultrasonography is necessary to exclude tubo-ovarian abscess (TOA) (grade C). Microbiological diagnosis requires endocervical and TOA sampling for molecular and bacteriological analysis (grade B). First-line treatment for uncomplicated PID combines ceftriaxone 1g, once, by intra-muscular (IM) or intra-venous (IV) route, doxycycline 100mg×2/d, and metronidazole 500mg×2/d oral (PO) for 10 days (grade A). First-line treatment for complicated PID combines IV ceftriaxone 1 to 2g/d until clinical improvement, doxycycline 100mg×2/d, IV or PO, and metronidazole 500mg×3/d, IV or PO for 14days (grade B). Drainage of TOA is indicated if the collection measures more than 3cm (grade B). Follow-up is required in women with sexually transmitted infections (STI) (grade C). The use of condoms is recommended (grade B). Vaginal sampling for microbiological diagnosis is recommended 3 to 6months after PID (grade C), before the insertion of an intra-uterine device (grade B), before elective termination of pregnancy or hysterosalpingography. Targeted antibiotics on identified bacteria are better than systematic antibioprophylaxis in those conditions. CONCLUSIONS: Current management of PID requires easily reproducible investigations and antibiotics adapted to STI and vaginal microbiota.


Assuntos
Doença Inflamatória Pélvica , Antibacterianos/administração & dosagem , Feminino , Humanos , Infecções/tratamento farmacológico , Infecções/microbiologia , Dispositivos Intrauterinos , Doença Inflamatória Pélvica/diagnóstico , Doença Inflamatória Pélvica/microbiologia , Doença Inflamatória Pélvica/terapia , Dor Pélvica , Infecções Sexualmente Transmissíveis , Ultrassonografia
10.
Med Mal Infect ; 48(2): 103-113, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29191391

RESUMO

OBJECTIVES: Streptococcus pneumoniae is the leading cause of community-acquired pneumonia. We aimed to analyze the epithelial response to S. pneumoniae-induced lung injury. METHODS: Using an in vitro model with 16HBE cells and experimental in vivo murine model of acute lung injury, we analyzed the epithelial response to S. pneumoniae. Lung epithelial cell monolayers were exposed to S. pneumoniae and permeability was assessed by transepithelial resistance (TER) measurement and organization and expression of junction proteins. Functional consequences were studied with an in vivo murine model measuring alveolar permeability, distal alveolar fluid clearance (DAFC), and the alveolar inflammatory response. RESULTS: In vitro, S. pneumoniae induced a dose-dependent decrease in transepithelial resistance, which was associated with significant modifications in the organization of junction proteins assessed by immunofluorescence staining and expression after 6hours of exposure. In vivo, S. pneumoniae induced a transient increase in alveolar permeability with an adequate increase in DAFC 6hours post infection. In a second phase, a permanent increased permeability was associated with a major decrease in DAFC. CONCLUSION: Overall, the epithelial response to S. pneumoniae followed a biphasic pattern with an initial reversible increase in permeability related to the alteration of tight and adherens junctions and a second phase associated with an epithelial injury with a major increase in permeability with a decreased DAFC reflecting an injured alveolar capillary barrier.


Assuntos
Lesão Pulmonar Aguda/microbiologia , Pneumonia Pneumocócica/complicações , Animais , Modelos Animais de Doenças , Feminino , Camundongos , Camundongos Endogâmicos C57BL
11.
Ann Dermatol Venereol ; 144(1): 45-48, 2017 Jan.
Artigo em Francês | MEDLINE | ID: mdl-28341191

RESUMO

BACKGROUND: Bacillus cereus is a ubiquitous telluric organism. B. cereus endocarditis is a rare condition seen mostly in prosthetic heart valves and among intravenous drug users. We report a new case of a patient without risk factors and with a good clinical outcome not requiring valve replacement. CASE REPORT: In October 2014, a 50-year-old woman was referred to the dermatology department of Lille University Hospital for lower-limb wounds developing 6 months earlier. She presented fever without clinical signs of infection, except for the lower-limbs wounds. Blood cultures revealed the presence of B. cereus. Transesophageal echocardiography was performed and revealed two foci of aortic valve vegetation with a diameter of 5mm. After bacterial sensitivity testing, rifampicin and levofloxacin treatment was given for six weeks, with complete remission. A skin graft was performed and good improvement was seen. DISCUSSION: Nineteen cases of B. cereus endocarditis have been described previously, only one of which was without risk factors. We described a case of complete remission after a 6-week course of antibiotics. Our case demonstrates that BC should not be considered as a blood culture contamination, and that treatment may be complex due to antibiotic resistance.


Assuntos
Antibacterianos/uso terapêutico , Bacillus cereus/isolamento & purificação , Endocardite/tratamento farmacológico , Endocardite/microbiologia , Úlcera da Perna/complicações , Levofloxacino/uso terapêutico , Rifampina/uso terapêutico , Quimioterapia Combinada , Endocardite/diagnóstico , Feminino , Humanos , Úlcera da Perna/microbiologia , Úlcera da Perna/terapia , Pessoa de Meia-Idade , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
12.
Clin Microbiol Infect ; 23(8): 576.e1-576.e5, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28192236

RESUMO

OBJECTIVES: Screening for primary immunodeficiencies (PIDs) in adults is recommended after two severe bacterial infections. We aimed to evaluate if screening should be performed after the first invasive infection in young adults. METHODS: Eligible patients were retrospectively identified using hospital discharge and bacteriology databases in three centres during a 3-year period. Eighteen to 40-year-old patients were included if they had experienced an invasive infection with encapsulated bacteria commonly encountered in PIDs (Streptococcus pneumoniae (SP), Neisseria meningitidis (NM), Neisseria gonorrhoeae (NG), Haemophilus influenzae (HI), or group A Streptococcus (GAS)). They were excluded in case of general or local predisposing factors. Immunological explorations and PIDs diagnoses were retrieved from medical records. Serum complement and IgG/A/M testings were systematically proposed at the time of study to patients with previously incomplete PID screening. RESULTS: The study population comprised 38 patients. Thirty-six had experienced a first invasive episode and a PID was diagnosed in seven (19%): two cases of common variable immunodeficiency revealed by SP bacteraemia, one case of idiopathic primary hypogammaglobulinaemia, and two cases of complement (C6 and C7) deficiency revealed by NM meningitis, one case of IgG2/IgG4 subclasses deficiency revealed by GAS bacteraemia, and one case of specific polysaccharide antibody deficiency revealed by HI meningitis. Two patients had previously experienced an invasive infection before the study period: in both cases, a complement deficiency was diagnosed after a second NM meningitis and a second NG bacteraemia, respectively. CONCLUSION: PID screening should be considered after a first unexplained invasive encapsulated-bacterial infection in young adults.


Assuntos
Bacteriemia/etiologia , Bacteriemia/imunologia , Proteínas do Sistema Complemento/deficiência , Síndromes de Imunodeficiência/complicações , Síndromes de Imunodeficiência/diagnóstico , Meningites Bacterianas/etiologia , Meningites Bacterianas/imunologia , Adolescente , Adulto , Feminino , Humanos , Fatores Imunológicos/deficiência , Masculino , Programas de Rastreamento/métodos , Prevalência , Estudos Retrospectivos , Adulto Jovem
14.
Med Mal Infect ; 46(4): 215-9, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27210283

RESUMO

BACKGROUND AND OBJECTIVES: Infections caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) have become a major public health issue worldwide. Cefoxitin is a second-generation cephalosporin and is associated with a strong in vitro activity against ESBL. PATIENTS AND METHODS: We conducted a prospective monocentric cohort study from 2012 to 2015 to evaluate the clinical efficacy and safety of cefoxitin in 15 patients treated for urinary tract infection (UTI) caused by ESBL-E, without any severity criteria. RESULTS: We included 15 patients; 11 were male patients with defined risk factors for ESBL-E. Ten patients presented with male UTI, three with pyelonephritis, and two with cystitis. Escherichia coli was the predominant pathogen. All patients had a positive outcome with a good tolerance (a skin rash without any sign of severity was observed in one patient). Microbiological cure was obtained in 9 patients out of 10 at the end of treatment. CONCLUSION: Cefoxitin is an alternative treatment to carbapenems for urinary tract infections caused by ESBL-producing Enterobacteriaceae.


Assuntos
Antibacterianos/uso terapêutico , Cefoxitina/uso terapêutico , Infecções por Escherichia coli/tratamento farmacológico , Infecções Urinárias/tratamento farmacológico , Resistência beta-Lactâmica , Antibacterianos/efeitos adversos , Proteínas de Bactérias/metabolismo , Cefoxitina/efeitos adversos , Toxidermias/etiologia , Feminino , Humanos , Infecções por Klebsiella/tratamento farmacológico , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento , Escherichia coli Uropatogênica/efeitos dos fármacos , Escherichia coli Uropatogênica/enzimologia , beta-Lactamases/metabolismo
15.
Med Mal Infect ; 46(2): 87-92, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26850899

RESUMO

BACKGROUND: Vascular thromboembolism (VTE) complicating cytomegalovirus (CMV) primary infection is increasingly reported in immunocompetent adults. No guideline is, however, currently available for the management of these infections and particularly for the antiviral therapy indication. METHODS: We performed a literature review of VTE complicating CMV primary infection in immunocompetent adults using PubMed. RESULTS: Sixty-nine case patients of VTE complicating CMV primary infection were reported. The main sites of venous thrombosis were the splanchnic veins (30 patients) or those of the lower limbs (18 patients). One-third of patients presented with pulmonary embolism (25 patients). Forty-nine patients (76%) had at least one VTE risk factor, inherited or acquired thrombophilia for 37 patients (58%), and another risk factor for 27 patients (42%). Only 11 patients received an antiviral therapy. A positive outcome was observed in all patients. CONCLUSION: We suggest that antiviral therapy should be considered for patients presenting with severe VTE, VTE with a negative outcome despite anticoagulation, severe organ involvement, or for patients managed in the intensive care unit.


Assuntos
Antivirais/uso terapêutico , Infecções por Citomegalovirus/complicações , Infecções por Citomegalovirus/tratamento farmacológico , Trombose/virologia , Humanos , Imunocompetência
16.
J Chromatogr A ; 1390: 71-7, 2015 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-25747666

RESUMO

A major challenge in countercurrent chromatography (CCC), the technique that works with a support-free biphasic liquid system, is to retain the liquid stationary phase inside the CCC column (Sf parameter). Two solutions are commercially available: the hydrostatic CCC columns, also called centrifugal partition chromatographs (CPC), with disks of interconnected channels and rotary seals, and the hydrodynamic CCC columns with bobbins of coiled open tube and no rotary seals. It was demonstrated that the amount of liquid stationary phase retained by a coiled tube was higher with larger bore tubing than with small bore tubes. At constant column volume, small bore tubing will be longer producing more efficiency than larger bore tube that will better retain the liquid stationary phase. Since the resolution equation in CCC is depending on both column efficiency and stationary phase retention ratio, the influence of the tubing bore should be studied. This theoretical work showed that there is an optimum tubing bore size depending on solute partition coefficient and mobile phase flow rate. The interesting result of the theoretical study is that larger tubing bores allow for dramatically reduced experiment durations for all solutes: in reversed phase CCC (polar mobile phase), hydrophobic solutes are usually highly retained. These apolar solutes can be separated by the same coil at high flow rates and reduced Sf with similar retention times as polar solutes separated at smaller flow rates and much higher Sf.


Assuntos
Cromatografia de Fase Reversa/métodos , Distribuição Contracorrente/métodos , Hidrodinâmica
17.
Methods Mol Biol ; 1274: 161-7, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25673491

RESUMO

Electrochromatography (EC) on a porous monolithic stationary phase prepared within the channels of a microsystem is an attractive alternative for on-chip separation. It combines the separation mechanisms of electrophoresis and liquid chromatography. Moreover, the porous polymer monolithic materials have become popular as stationary phase due to the ease and rapidity of fabrication via free radical photopolymerization. Here, we describe a hexyl acrylate (HA)-based porous monolith which is simultaneously in situ synthesized and anchored to the inner walls of the channel of a cyclic olefin copolymer (COC) device in only 2 min. The baseline separation of a mixture of neurotransmitters including six amino acids and two catecholamines is realized.


Assuntos
Acrilatos/química , Eletrocromatografia Capilar/métodos , Cicloparafinas/química , Polímeros/química
18.
Reanimation ; 24(Suppl 2): 379-385, 2015.
Artigo em Francês | MEDLINE | ID: mdl-32288742

RESUMO

In the last decade, we faced a large number of emerging pathogens. As a consequence we had to adapt our medical practice as well as our health system. This review summarizes the main features of the recent emerging pathogens with a particular focus on the recent and ongoing Ebola outbreak, we tried to evaluate the consequences on our national health management.

19.
Anal Bioanal Chem ; 406(24): 5919-26, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25084735

RESUMO

The previous article in this series described the physico-chemical properties and chemical compositions of the two phases of the limonene-ethyl acetate-ethanol-water biphasic liquid system. This system was designed to be a "green" version of the so-called Arizona (AZ) scale of heptane-ethyl acetate-methanol compositions in which the heptane-ethyl acetate volume ratio is exactly the same as the methanol-water ratio. The first major difference between the standard and "green" AZ systems is the difference in upper and lower phase densities. The higher density of limonene compared with heptane greatly reduces the density difference of the "green" system: half the compositions have a density difference lower than 0.06 g mL(-1), precluding their use in hydrodynamic CCC columns. The other major difference is the phase polarity. The better distribution of ethanol between the upper organic and lower aqueous phases of the "green" AZ scale renders them more polar than their counterparts in standard heptane-based compositions. The test solutes aspirin and coumarin have higher distribution constants in the "green" AZ compositions. It is revealed that a hydrostatic column is suitable for use with all "green" compositions, with very good phase retention and limited driving pressure at high flow rates. A hydrodynamic column only functioned at limited flow rates with polar compositions of sufficient phase-density difference. The CCC chromatograms obtained with different compositions and columns are shown, and their peak position and sharpness discussed.

20.
Med Mal Infect ; 43(4): 146-51, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23622953

RESUMO

Pseudomonas aeruginosa and Candida albicans are frequently coexisting opportunistic pathogens, responsible for colonization and infection in predisposed patients. They share a virulence specificity relying on auto-inducing, cell density-dependent molecules named quorum-sensing (QS). C. albicans virulence depends on its QS that influences morphological switch from yeast to filamentous form. Similarly, the production of P. aeruginosa virulence factors depends partly on QS molecules. Interactions have been investigated and demonstrated in vitro. P. aeruginosa may kill C. albicans either by producing toxins, such as pyocyanin, or by direct contact on its biofilm-dependent filamentous form. Cross-kingdom communication is a more subtle interaction: C. albicans can adapt its morphology in the presence of P. aeruginosa QS molecules, and inhibit P. aeruginosa QS-dependent virulence factor secretion, through farnesol, one of its QS molecule. But the in vivo relevance of these interactions is still controversial, as models of airway colonization/infection by C. albicans followed by subsequent P. aeruginosa pneumonia give contradictory results, suggesting the probable involvement of the immune system as a third party player. Finally, the authors of clinical studies performed in ventilated patients, indicate that C. albicans colonization could be a risk factor for P. aeruginosa pneumonia. The clinical outcome of C. albicans and P. aeruginosa interaction is uncertain, the virulence modulation demonstrated in these interactions opens new possibilities for future anti-infectious therapeutics.


Assuntos
Candida albicans/patogenicidade , Candidíase/microbiologia , Infecções Oportunistas/microbiologia , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/patogenicidade , Biofilmes , Candida albicans/ultraestrutura , Coinfecção , Interações Hospedeiro-Patógeno , Humanos , Percepção de Quorum/fisiologia , Virulência/fisiologia
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