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1.
Nephrol Dial Transplant ; 39(4): 627-636, 2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-37667539

RESUMEN

BACKGROUND: While opportunistic infections are a frequent and challenging problem in kidney transplant recipients, their long-term epidemiology remains hardly known. METHODS: Opportunistic infections were recorded in 1144 recipients transplanted in our center between 2004 and 2015. Incidence rates and baseline risk factors were determined using joint frailty models. RESULTS: After a median follow-up of 5.6 years, 544 opportunistic infections occurred in 373/1144 (33%) patients, dominated by viral infections (396/544, 72%), especially cytomegalovirus (CMV) syndromes and diseases (213/544, 39%). One-third of the infected patients experienced at least two opportunistic infections. The incidence of opportunistic infections was 10 times higher during the first year post-transplantation than after that (34.7 infections for 100 patient-years vs 3.64). Opportunistic infections associated with the age of the donor (P = .032), the age of the recipient (P = .049), the CMV serostatus (P < 10-6), a higher class II HLA mismatch (P = .032) and an induction treatment including rabbit anti-thymocyte globulins (P = .026). Repeated opportunistic infections associated with each other (P < 10-6) and with renal death (P < 10-6). CONCLUSION: Opportunistic infections occur with a two-period incidence pattern and many susceptible patients suffer from repeated episodes. This knowledge may help tailor new prevention and follow-up strategies to reduce the burden of opportunistic infections and their impact on transplantation outcome.


Asunto(s)
Infecciones por Citomegalovirus , Trasplante de Riñón , Infecciones Oportunistas , Humanos , Infecciones por Citomegalovirus/tratamiento farmacológico , Antivirales/uso terapéutico , Trasplante de Riñón/efectos adversos , Estudios Retrospectivos , Factores de Riesgo , Citomegalovirus , Infecciones Oportunistas/etiología , Receptores de Trasplantes
2.
Artículo en Inglés | MEDLINE | ID: mdl-30323045

RESUMEN

A clinical Pseudomonas aeruginosa isolate resistant to all ß-lactams, including ceftolozane-tazobactam and carbapenems, was recovered. It belonged to sequence type 235 and produced the extended-spectrum ß-lactamase (ESBL) GES-6 differing from GES-1 by two amino acid substitutions (E104K and G170S). GES-6 possessed an increased hydrolytic activity toward carbapenems and to ceftolozane and a decreased susceptibility to ß-lactamase inhibitors compared to GES-1, except for avibactam. We show here that resistance to ceftolozane-tazobactam may occur through acquisition of a specific ESBL in P. aeruginosa but that ceftazidime-avibactam combination remains an effective alternative.


Asunto(s)
Antibacterianos/farmacología , Carbapenémicos/farmacología , Cefalosporinas/farmacología , Pseudomonas aeruginosa/genética , Tazobactam/farmacología , Resistencia betalactámica/genética , beta-Lactamasas/genética , Sustitución de Aminoácidos , Compuestos de Azabiciclo/farmacología , Ceftazidima/farmacología , Combinación de Medicamentos , Expresión Génica , Humanos , Pruebas de Sensibilidad Microbiana , Infecciones por Pseudomonas/tratamiento farmacológico , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/enzimología , Pseudomonas aeruginosa/aislamiento & purificación , Resistencia betalactámica/efectos de los fármacos , beta-Lactamasas/metabolismo
3.
J Clin Microbiol ; 56(9)2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29976591

RESUMEN

A whole-genome sequencing (WGS) approach was conducted in order to identify the molecular determinants associated with antimicrobial resistance in 12 multidrug-resistant Campylobacter jejuni and Campylobacter coli isolates, with a focus on aminoglycoside resistance determinants. Two variants of a new aminoglycoside phosphotransferase gene [aph(2″)-Ii1 and aph(2″)-Ii2 ] putatively associated with gentamicin resistance were found. In addition, the following new genes were identified for the first time in Campylobacter: a lincosamide nucleotidyltransferase gene [lnu(G)], likely associated with lincomycin resistance, and two resistance enzyme genes (spw and apmA) similar to those found in Staphylococcus aureus, which may confer spectinomycin and gentamicin resistance, respectively. A C1192T mutation of the 16S rRNA gene that may be involved in spectinomycin resistance was also found in a C. coli isolate. Genes identified in the present study were located either on the bacterial chromosome or on plasmids that could be transferred naturally. Their role in aminoglycoside resistance remains to be supported by genetic studies. Regarding the other antimicrobial agents studied, i.e., ampicillin, ciprofloxacin, erythromycin, and tetracycline, a perfect correlation between antimicrobial phenotypes and genotypes was found. Overall, our data suggest that WGS analysis is a powerful tool for identifying resistance determinants in Campylobacter and can disclose the full genetic elements associated with resistance, including antimicrobial compounds not tested routinely in antimicrobial susceptibility testing.


Asunto(s)
Aminoglicósidos/farmacología , Antibacterianos/farmacología , Infecciones por Campylobacter/microbiología , Campylobacter/genética , Campylobacter/aislamiento & purificación , Farmacorresistencia Bacteriana Múltiple/genética , Genoma Bacteriano/genética , Animales , Proteínas Bacterianas/genética , Campylobacter/clasificación , Campylobacter/efectos de los fármacos , Campylobacter coli/clasificación , Campylobacter coli/efectos de los fármacos , Campylobacter coli/genética , Campylobacter coli/aislamiento & purificación , Campylobacter jejuni/clasificación , Campylobacter jejuni/efectos de los fármacos , Campylobacter jejuni/aislamiento & purificación , ADN Bacteriano/genética , Humanos , Mutación , Filogenia , Plásmidos , ARN Ribosómico 16S/genética , Carne Roja/microbiología , Análisis de Secuencia de ADN
4.
J Antimicrob Chemother ; 73(5): 1272-1278, 2018 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-29481600

RESUMEN

Background: The broth microdilution (BMD) method is currently the recommended technique to determine susceptibility to colistin. Objectives: We evaluated the accuracy of three commercialized BMD panels [Sensititre (ThermoFisher Diagnostics), UMIC (Biocentric) and MicroScan (Beckman Coulter)] to determine colistin susceptibility. Methods: A collection of 185 isolates of Gram-negative bacilli (133 colistin resistant and 52 colistin susceptible) was tested. Manual BMD according to EUCAST guidelines was used as the reference method, and EUCAST 2017 breakpoints were used for susceptibility categorization. Results: The UMIC system gave the highest rate of very major errors (11.3%) compared with the Sensititre and MicroScan systems (3% and 0.8%, respectively). A high rate of major errors (26.9%) was found with the MicroScan system due to an overestimation of the MICs for the non-fermenting Gram-negative bacilli, whereas no major errors were found with the Sensititre and UMIC systems. Conclusions: The UMIC system was easy to use, but failed to detect >10% of colistin-resistant isolates. The MicroScan system showed excellent results for enterobacterial isolates, but non-susceptible results for non-fermenters should be confirmed by another method and the range of MICs tested was narrow. The Sensititre system was the most reliable marketed BMD panel with a categorical agreement of 97.8%.


Asunto(s)
Antibacterianos/farmacología , Colistina/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Errores Diagnósticos , Sensibilidad y Especificidad
5.
Artículo en Inglés | MEDLINE | ID: mdl-28874377

RESUMEN

Mutations in crrAB genes encoding a two-component regulator involved in modifications of lipopolysaccharide were searched for among a collection of colistin-resistant Klebsiella pneumoniae isolates. Four isolates, respectively, producing carbapenemases NDM-1, OXA-181, or KPC-2 showed mutated CrrB proteins compared with those in wild-type strains. Complementation assays with a wild-type CrrB protein restored the susceptibility to colistin in all cases, confirming the involvement of the identified substitutions in the resistance phenotype.


Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/genética , Colistina/farmacología , Farmacorresistencia Bacteriana/genética , Klebsiella pneumoniae/efectos de los fármacos , Sustitución de Aminoácidos , Proteínas Bacterianas/metabolismo , Farmacorresistencia Bacteriana/efectos de los fármacos , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Prueba de Complementación Genética , Humanos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/aislamiento & purificación , Klebsiella pneumoniae/metabolismo , Pruebas de Sensibilidad Microbiana , Mutación , beta-Lactamasas/genética , beta-Lactamasas/metabolismo
6.
J Antimicrob Chemother ; 72(9): 2507-2511, 2017 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-28586429

RESUMEN

Objectives: To determine the susceptibility to colistin of Hafnia alvei and Hafnia paralvei, and to compare methods for colistin resistance detection in the Hafnia genus. Methods: A collection of 25 Hafnia isolates was studied. Species were identified by using 16S rRNA gene sequencing with subsequent phylogeny analysis. Susceptibility to colistin was determined using the broth microdilution (BMD) reference method, the Phoenix automated system, the Rapid Polymyxin NP test, the Etest system and the disc diffusion method. Results: The collection consisted of 15 H. alvei and 10 H. paralvei isolates. Based on the 16S rRNA analysis, a close relationship of the Hafnia genus with naturally colistin-resistant enterobacterial genera (Proteus, Morganella, Providencia and Serratia) was identified. Susceptibility testing performed using the BMD method, the Phoenix automated system and the Rapid Polymyxin NP test revealed a high rate of colistin resistance (96%). Underestimation of colistin resistance using Etest strips (72%) and the disc diffusion method (0%) was observed. Conclusions: The high rate of colistin resistance observed within the Hafnia genus and its close phylogenetic relationship with naturally colistin-resistant genera suggest that Hafnia is a naturally colistin-resistant enterobacterial genus.


Asunto(s)
Antibacterianos/farmacología , Colistina/farmacología , Hafnia/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Pruebas Antimicrobianas de Difusión por Disco , Farmacorresistencia Bacteriana Múltiple , Infecciones por Enterobacteriaceae/microbiología , Hafnia/clasificación , Hafnia/genética , Humanos , Tipificación Molecular , Filogenia , ARN Ribosómico 16S/genética
7.
J Clin Microbiol ; 54(9): 2273-7, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27307457

RESUMEN

Enterobacterial strains resistant to polymyxins are being increasingly reported worldwide. The conventional methods for detection of colistin-resistant isolates such as broth microdilution remain time-consuming (24 to 48 h), and methods such as disc diffusion and Etest are not reliable. Recently, the rapid polymyxin NP test was developed for rapid identification of polymyxin-resistant Enterobacteriaceae This test is based on the detection of glucose metabolism related to bacterial growth in the presence of a defined concentration of colistin (or polymyxin B). The formation of acid metabolites is evidenced by a color change of a pH indicator (red phenol) in less than 2 h. In this study, the polymyxin NP test was evaluated for detection of colistin-resistant Enterobacteriaceae directly from blood cultures. The test was performed with 73 blood culture sets (either spiked or clinical blood cultures) with various enterobacterial species. The test exhibited excellent discrimination between polymyxin-resistant and polymyxin-susceptible enterobacterial isolates, and results are obtained from blood cultures within 4 h. It is easy to perform and requires neither subculture nor a centrifugation step. This test is rapid, specific, and sensitive and allows early identification of polymyxin-resistant Enterobacteriaceae directly from blood cultures.


Asunto(s)
Antibacterianos/farmacología , Cultivo de Sangre/métodos , Farmacorresistencia Bacteriana , Infecciones por Enterobacteriaceae/diagnóstico , Enterobacteriaceae/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Polimixinas/farmacología , Color , Enterobacteriaceae/aislamiento & purificación , Infecciones por Enterobacteriaceae/microbiología , Humanos , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Sensibilidad y Especificidad , Factores de Tiempo
8.
Nurs Ethics ; 23(2): 191-202, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25488762

RESUMEN

BACKGROUND AND PURPOSE: Providing non-therapeutic intensive care for some patients in hopeless condition after cerebrovascular stroke in order to protect their organs for possible post-mortem organ donation after brain death is an effective but ethically tricky strategy to increase organ grafting. Finding out the feelings and opinion of the involved healthcare professionals and assessing the training needs before implementing such a strategy is critical to avoid backlash even in a presumed consent system. PARTICIPANTS AND METHODS: A single-centre opinion survey of healthcare professionals was conducted in 2013 in the potentially involved wards of a French University Hospital: the Neurosurgical, Surgical and Medical Intensive Care Units, the Stroke Unit and the Emergency Department. A questionnaire with multiple-choice questions and one open-ended question was made available in the different wards between February and May 2013. ETHICAL CONSIDERATIONS: The project was approved by the board of the Lorraine University Diploma in Medical Ethics. RESULTS: Of a total of 340 healthcare professionals, 51% filled the form. Only 21.8% received a specific education on brain death, and only 18% on potential donor's family approach and support. Most healthcare professionals (93%) think that non-therapeutic intensive care is the continuity of patient's care. But more than 75% of respondents think that the advance patient's consent and the consent of the family must be obtained despite the presumed consent rule regarding post-mortem organ donation in France. CONCLUSION: The acceptance by healthcare professionals of non-therapeutic intensive care for brain death organ donation seems fairly good, despite a suboptimal education regarding brain death, non-therapeutic intensive care and families' support. But they ask to require previously expressed patient's consent and family's approval. So, it seems that non-therapeutic intensive care should only remain an ethically sound mean of empowerment of organ donors and their families to make post-mortem donation happen as a full respect of individual autonomy.


Asunto(s)
Actitud del Personal de Salud , Muerte Encefálica , Cuidados Críticos/ética , Cuerpo Médico de Hospitales/psicología , Asistentes de Enfermería/psicología , Personal de Enfermería en Hospital/psicología , Obtención de Tejidos y Órganos , Francia , Hospitales Universitarios , Humanos , Cuerpo Médico de Hospitales/estadística & datos numéricos , Evaluación de Necesidades , Asistentes de Enfermería/estadística & datos numéricos , Personal de Enfermería en Hospital/estadística & datos numéricos , Consentimiento Presumido/ética , Relaciones Profesional-Familia , Encuestas y Cuestionarios
9.
Phys Chem Chem Phys ; 16(16): 7339-49, 2014 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-24623310

RESUMEN

We show in the case of N,N'-dimethyl-N,N'-dioctyl-2-(2(hexyloxy)ethyl)-malonamide (DMDOHEMA) chosen as a typical oil-soluble extractant with surface activity that the free energy of formation of reverse micelles in the solvent phase strongly depends on the presence of polar solutes. Free energies per molecule vary typically from 0 to 2 kT per molecule (5 kJ mol(-1)), depending on the kosmotropic/chaotropic nature of the anion extracted. Variations of the reverse aggregation free energy introduced by acids and other co-extracted solutes as deduced from the critical aggregation concentrations cannot be neglected while modelling extraction. With typical aggregation numbers of 4-6, the free energy of formation of one reverse aggregate varies up to 20 kJ mol(-1), which is four times the typical difference in free energy of one single cation transfer between a "target" and a non-target ion in practical extraction and stripping industrial processes.

10.
Pharmaceuticals (Basel) ; 17(3)2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38543091

RESUMEN

Antimicrobial resistance (AMR) is a global public health threat. Quality data are needed to address the rise of multidrug-resistant clones, particularly in sub-Saharan Africa. In this study, we analysed the prevalence, antimicrobial resistance profile, and presence of genes encoding extended-spectrum ß-lactamase-producing Escherichia coli (ESBL-Ec) and Klebsiella pneumoniae (ESBL-Kp) in environmental samples from Ouagadougou, Burkina Faso. Of 264 samples collected, 95 (36%) and 74 (28%) contained ESBL-Kp and ESBL-Ec, respectively. ESBL-Kp was more prevalent in runoff water and in treated and untreated wastewater, while ESBL-Ec was more prevalent in manure. Interestingly, wastewater treatment did not significantly reduce the recovery of ESBL bacteria. As expected, resistance to third- and fourth-generation cephalosporins was predominant, and rare for second generation cefoxitin. Interestingly, all the isolates from treated wastewater were susceptible to ampicillin and piperacillin, while all the other clones were resistant to these antibiotics. Regarding the ESBL-encoding genes, the blaCTX-M family was the most abundant, with the blaCTX-M1 subfamily being the most prevalent. Carriage of combinations of ESBL genes was common, with the majority of the isolates harbouring 2-4 different genes. This study highlights the need for active surveillance to manage the risk of exposure to ESBL bacteria in Burkina Faso.

12.
Clin Kidney J ; 16(3): 494-500, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36865002

RESUMEN

Background: Catheter-related bloodstream infections (CRBIs) remain a major cause of mortality in haemodialysis (HD) patients with central venous catheters (CVCs), especially because of the non-specific symptomatology and the delay in microbiological diagnosis with possible use of non-optimal empiric antibiotics. Moreover, empiric broad-spectrum antibiotics increase antibiotic resistance development. This study aims to evaluate the diagnostic performance of real-time polymerase chain reaction (rt-PCR) in suspected HD CRBIs compared with blood cultures. Methods: A blood sample for rt-PCR was collected simultaneously with each pair of blood cultures for suspected HD CRBI. The rt-PCR was performed on the whole blood, without any enrichment stage and with specific DNA primers: 16S (universal bacterial), Staphylococcus spp., Staphylococcus aureus and mecA. Each successive patient with a suspected HD CRBI in the HD centre of Bordeaux University Hospital was included. Performance tests were used to compare the result obtained in each rt-PCR assay with its corresponding routine blood culture. Results: Eighty-four paired samples were collected and compared for 40 suspected HD CRBI events in 37 patients. Among these, 13 (32.5%) were diagnosed as HD CRBI. All rt-PCRs except mecA (insufficient number of positive samples) showed high diagnostic performances within 3.5 h: 16S (sensitivity 100%, specificity 78%), Staphylococcus spp. (sensitivity 100%, specificity 97%), S. aureus (sensitivity 100%, specificity 99%). Based on the rt-PCR results, antibiotics could be more appropriately targeted, thus cutting anti-cocci Gram-positive therapy from 77% to 29%. Conclusions: The performance of rt-PCR in suspected HD CRBI events showed fast and high diagnostic accuracy. Its use would improve HD CRBI management with an antibiotic consumption decrease.

13.
Ann Intensive Care ; 13(1): 25, 2023 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-37014580

RESUMEN

BACKGROUND: The worldwide dissemination of extended spectrum beta-lactamase producing Enterobacteriales (ESBL-E) is of major concern. Microbiota may play a role in the host resistance to colonization with ESBL-E, but the underlying mechanisms remain unknown. We aimed to compare the gut microbiota composition between ESBL-producing E. coli or K. pneumoniae carriers and ESBL-E non-carriers according to the bacterial species. RESULTS: Among 255 patients included, 11 (4,3%) were colonized with ESBL-producing E. coli and 6 (2,4%) with ESBL-producing K. pneumoniae, which were compared with age- and sex-matched ESBL-E non carriers. While no significant differences were found between ESBL-producing E. coli carriers and non-carriers, gut bacteriobiota α-diversity was decreased in ESBL-K. pneumoniae faecal carriers compared both with non-carriers (p = 0.05), and with ESBL-producing E. coli carriers. The presence of Sellimonas intestinalis was associated with the absence of ESBL-producing E. coli fecal carriage. Campylobacter ureolyticus, Campylobacter hominis, bacteria belonging to Clostridium cluster XI and Saccharomyces sp. were associated with the absence of ESBL-producing K. pneumoniae faecal carriage. CONCLUSIONS: The composition of the gut microbiota differs between ESBL-producing E. coli and K. pneumoniae faecal carriers suggesting that microbial species should be taken into account when investigating the role of gut microbiota in resistance to gut colonization with ESBL-E. TRIAL REGISTRATION NUMBER: NCT04131569, date of registration: October 18, 2019.

14.
Antibiotics (Basel) ; 12(10)2023 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-37887195

RESUMEN

Hospital wastewater is a recognized reservoir for resistant Gram-negative bacteria. This study aimed to screen for carbapenemase-producing Escherichia coli and Klebsiella pneumoniae and their resistance determinants in two hospital effluents of Ouagadougou. Carbapenem-resistant E. coli and K. pneumoniae were selectively isolated from wastewater collected from two public hospitals in Ouagadougou, Burkina Faso. Bacterial species were identified via MALDI-TOF mass spectrometry. Carbapenemase production was studied phenotypically using antibiotic susceptibility testing via the disk diffusion method. The presence of carbapenemases was further characterized by PCR. A total of 14 E. coli (13.59%) and 19 K. pneumoniae (17.92%) carbapenemase-producing isolates were identified with different distributions. They were, respectively, blaNDM (71.43%), blaVIM (42.86%), blaIMP (28.57%), blaKPC (14.29%), blaOXA-48 (14.29%); and blaKPC (68.42%), blaNDM (68.42%), blaIMP (10.53%), blaVIM (10.53%), and blaOXA-48 (5.26%). In addition, eight (57.14%) E. coli and eleven (57.89%) K. pneumoniae isolates exhibited more than one carbapenemase, KPC and NDM being the most prevalent combination. Our results highlight the presence of clinically relevant carbapenemase-producing isolates in hospital effluents, suggesting their presence also in hospitals. Their spread into the environment via hospital effluents calls for intensive antimicrobial resistance (AMR) surveillance.

15.
Antibiotics (Basel) ; 11(2)2022 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-35203729

RESUMEN

Tripartite multidrug RND efflux systems made of an inner membrane transporter, an outer membrane factor (OMF) and a periplasmic adaptor protein (PAP) form a canal to expel drugs across Gram-negative cell wall. Structures of MexA-MexB-OprM and AcrA-AcrB-TolC, from Pseudomonas aeruginosa and Escherichia coli, respectively, depict a reduced interfacial contact between OMF and PAP, making unclear the comprehension of how OMF is recruited. Here, we show that a Q93R mutation of MexA located in the α-hairpin domain increases antibiotic resistance in the MexAQ93R-MexB-OprM-expressed strain. Electron microscopy single-particle analysis reveals that this mutation promotes the formation of tripartite complexes with OprM and non-cognate components OprN and TolC. Evidence indicates that MexAQ93R self-assembles into a hexameric form, likely due to interprotomer interactions between paired R93 and D113 amino acids. C-terminal deletion of OprM prevents the formation of tripartite complexes when mixed with MexA and MexB components but not when replacing MexA with MexAQ93R. This study reveals the Q93R MexA mutation and the OprM C-terminal peptide as molecular determinants modulating the assembly process efficacy with cognate and non-cognate OMFs, even though they are outside the interfacial contact. It provides insights into how OMF selectivity operates during the formation of the tripartite complex.

16.
Nephrol Ther ; 18(2): 80-88, 2022 Apr.
Artículo en Francés | MEDLINE | ID: mdl-35033479

RESUMEN

Patients in hemodialysis on central venous catheter as vascular access are at risk of infections. Catheter-related bloodstream infection is one of the most serious catheter-complications in hemodialysis patients. Its clinical and microbiological diagnosis is challenging. The implementation of empiric antibiotic therapy is based on old recommendations proposing the combination of a molecule targeting methicillin-resistant Staphylococcus aureus and a betalactamin active on P. aeruginosa, and also adapting this probabilistic treatment by carrying out a microbiological register on a local scale, which is rarely done. In our hemodialysis center at Bordeaux University Hospital, an analysis of the microorganisms causing all catheter-related bloodstream infection over the period 2018-2020 enabled us to propose, in agreement with the infectious disease specialists, an adapted probabilistic antibiotic therapy protocol. This approach allowed us to observe a low incidence of meticillinoresistance of Staphylococcus. For catheters inserted more than 6 months ago, we observed no Staphylococcus, no multi-resistant Pseudomonas, and only 2% of Enterobacteria resistant to cephalosporins. A frequent updating of the microbiological epidemiology of catheter-related bloodstream infection, in partnership with the infectious diseases team in each hemodialysis center, allowing an adaptation of the probabilistic antibiotic therapy, and seems to have a good feasibility. This strategy might favor the preservation of microbial ecology on an individual and collective scale in maintenance hemodialysis patients.


Asunto(s)
Bacteriemia , Infecciones Relacionadas con Catéteres , Cateterismo Venoso Central , Catéteres Venosos Centrales , Staphylococcus aureus Resistente a Meticilina , Antibacterianos/uso terapéutico , Bacteriemia/diagnóstico , Bacteriemia/tratamiento farmacológico , Bacteriemia/epidemiología , Infecciones Relacionadas con Catéteres/diagnóstico , Infecciones Relacionadas con Catéteres/tratamiento farmacológico , Infecciones Relacionadas con Catéteres/epidemiología , Cateterismo Venoso Central/efectos adversos , Catéteres Venosos Centrales/efectos adversos , Humanos , Diálisis Renal/efectos adversos
17.
Biochim Biophys Acta ; 1804(4): 781-8, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20026260

RESUMEN

The dipeptidyl peptidases (DPP) 8 and 9 belong to the DPP4 activity and/or structure homologues (DASH). Recently, a DPP9-like protein was purified from bovine testes. The aim of the present study was to prove its identity and to investigate the characteristics of this natural enzyme. We report the identification and N-terminal sequence analysis by MALDI-TOF/TOF MS, of the purified bovine enzyme as DPP9. The tryptic peptides after in-gel digestion covered 41% and 38% of the short and full-length variants of bovine DPP9, respectively. Using Asp-N digestion combined with a very recently described mass spectrometric method using DITC glass beads, the N-terminal peptide (XTGALTSERG) was isolated. It corresponds to the N-terminus of the short form of bovine DPP9. There was no evidence for glycosylation of purified bovine DPP9. The purified DPP9 was activated and stabilized by DTT. Bovine DPP9 lost its activity almost completely after alkylation with N-ethylmaleimide. Also alkylation with iodoacetamide inhibited DPP9, albeit only 70%. Other properties of bovine DPP9 are reported, including functional stability and sensitivity towards metal ions. Our results indicate that the short form of DPP9 can be isolated from bovine testes and that it behaves as a stable enzyme suitable for further functional and biochemical characterization as well as for inhibitor screening and characterization.


Asunto(s)
Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/química , Testículo/enzimología , Secuencia de Aminoácidos , Animales , Bovinos , Cromatografía Líquida de Alta Presión , Cromatografía de Fase Inversa , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/genética , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/aislamiento & purificación , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/metabolismo , Estabilidad de Enzimas , Humanos , Técnicas In Vitro , Cinética , Masculino , Datos de Secuencia Molecular , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/aislamiento & purificación , Homología de Secuencia de Aminoácido , Especificidad de la Especie , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectrometría de Masas en Tándem , Tripsina
18.
Microbiology (Reading) ; 157(Pt 2): 496-503, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20966089

RESUMEN

In a collection of 110 clinical isolates of Klebsiella pneumoniae, a single strain, Kp593, was found to exhibit a mutator phenotype with a rifampicin mutation frequency 100-fold higher than the modal value for this species. Complementation experiments with the wild-type MutL, one of the main components of the methyl-directed mismatch repair system, allowed the mutator phenotype to be reversed. Sequencing revealed substitution of the conserved residue Lys307 to Arg and site-directed mutagenesis followed by complementation experiments confirmed the critical role of this mutation. The patient infected with Kp593 relapsed a month later and the strain isolated then, Kp869, was identical to Kp593, as verified by PFGE analysis. Phenotypically, Kp869 colonies were more mucoid than those of Kp593, probably due to increased capsule synthesis as shown by electron microscopy. In addition, Kp869 exhibited a 16-fold higher amoxicillin resistance level related to a 36.4 kb tandem duplication encompassing the chromosomal bla(SHV-11) gene, which was unstable in vitro. These data suggest that the mutator phenotype found in Kp593/Kp869 is associated with beneficial mutations conferring a selective advantage, such as increased virulence factor production and antibiotic resistance. The latter was due to resistance gene duplication, an event rarely described in natural isolates. This is the first description of the in vivo occurrence of gene duplication in a mutator background.


Asunto(s)
Duplicación de Gen , Klebsiella pneumoniae/genética , beta-Lactamasas/genética , Anciano de 80 o más Años , Clonación Molecular , ADN Bacteriano/genética , Farmacorresistencia Bacteriana , Femenino , Prueba de Complementación Genética , Humanos , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/enzimología , Klebsiella pneumoniae/patogenicidad , Pruebas de Sensibilidad Microbiana , Proteína MutS de Unión a los Apareamientos Incorrectos del ADN/genética , Mutagénesis Sitio-Dirigida , Mutación , Fenotipo , Análisis de Secuencia de ADN , Virulencia , beta-Lactamas/farmacología
19.
Biol Chem ; 392(3): 189-98, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21194356

RESUMEN

Dipeptidyl peptidase IV (DPPIV)/CD26 is by far the most extensively studied member of the prolyl oligopeptidase family of serine proteases. The discovery of the related enzymes DPP8 and DPP9 necessitates a (re-)evaluation of the DPPIV-like enzymatic activity in cells and organs. In this study, we aimed (1) to investigate the expression of the individual dipeptidyl peptidases in different types of endothelial cells (ECs) and (2) to reconsider published data in relation to our findings. Examination of DPP expression in rat primary ECs of aortic, endocardial and cardiac microvascular origin revealed the presence of DPPIV-like activity in all cell lysates. More than half of this activity could be attributed to DPP8/9. Western blot analysis revealed an abundance of the DPP8 protein as compared to DPP9. The expression of DPPIV and DPP8 was significantly higher in the cardiac microvascular endothelium than in the other ECs, suggesting a more pronounced role of these DPPs in the microvasculature. In situ, DPP activity in ventricular microvasculature was completely inhibited by sitagliptin, indicating that DPPIV is the predominant DPPIV-like enzyme in this organ. By contrast, immunohistochemical studies indicated DPP9 as the predominant DPP in human carotid artery ECs. In conclusion, our results support a highly regulated expression of individual DPPs in ECs, with a spatial heterogeneity in the cardiovascular tree.


Asunto(s)
Dipeptidil Peptidasa 4/metabolismo , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/metabolismo , Células Endoteliales/enzimología , Endotelio Vascular/enzimología , Animales , Aorta/citología , Aorta/enzimología , Capilares/citología , Arterias Carótidas/citología , Arterias Carótidas/enzimología , Línea Celular , Inhibidores de la Dipeptidil-Peptidasa IV/farmacología , Células Endoteliales/efectos de los fármacos , Endotelio Vascular/citología , Humanos , Miocardio/enzimología , Pirazinas/farmacología , Ratas , Fosfato de Sitagliptina , Triazoles/farmacología
20.
BMC Infect Dis ; 11: 120, 2011 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-21569334

RESUMEN

BACKGROUND: Patients with Enterobacter community-acquired pneumonia (EnCAP) were admitted to our intensive care unit (ICU). Our primary aim was to describe them as few data are available on EnCAP. A comparison with CAP due to common and typical bacteria was performed. METHODS: Baseline clinical, biological and radiographic characteristics, criteria for health-care-associated pneumonia (HCAP) were compared between each case of EnCAP and thirty age-matched typical CAP cases. A univariate and multivariate logistic regression analysis was performed to determine factors independently associated with ENCAP. Their outcome was also compared. RESULTS: In comparison with CAP due to common bacteria, a lower leukocytosis and constant HCAP criteria were associated with EnCAP. Empiric antibiotic therapy was less effective in EnCAP (20%) than in typical CAP (97%) (p < 0.01). A delay in the initiation of appropriate antibiotic therapy (3.3 ± 1.6 vs. 1.2 ± 0.6 days; p < 0.01) and an increase in duration of mechanical ventilation (8.4 ± 5.2 vs. 4.0 ± 4.3 days; p = 0.01) and ICU stay were observed in EnCAP patients. CONCLUSIONS: EnCAP is a severe infection which is more consistent with HCAP than with typical CAP. This retrospectively suggests that the application of HCAP guidelines should have improved EnCAP management.


Asunto(s)
Concienciación , Infecciones Comunitarias Adquiridas/psicología , Infección Hospitalaria/psicología , Enterobacter/aislamiento & purificación , Neumonía Bacteriana/psicología , Adulto , Anciano , Anciano de 80 o más Años , Antibacterianos/uso terapéutico , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Infecciones Comunitarias Adquiridas/microbiología , Infección Hospitalaria/tratamiento farmacológico , Infección Hospitalaria/microbiología , Enterobacter/genética , Enterobacter/fisiología , Femenino , Hospitalización , Humanos , Unidades de Cuidados Intensivos , Masculino , Persona de Mediana Edad , Neumonía Bacteriana/tratamiento farmacológico , Neumonía Bacteriana/microbiología , Estudios Retrospectivos , Índice de Severidad de la Enfermedad
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