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1.
Infect Dis Now ; 54(5): 104922, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38754702

RESUMEN

OBJECTIVE: Acute graft pyelonephritis (AGPN) is the most frequent infectious complication in kidney transplant recipients (KTR). The treatment of acute community-acquired (CA) pyelonephritis is based on third-generation cephalosporins (3GC) and fluoroquinolones. Cefepime or a piperacillin-tazobactam combination are more often used in healthcare-associated (HCA) infections. However, these recommendations do not consider the resistance observed in KTRs. The objective of our study was to define the most appropriate empirical antibiotherapy for AGPN in KTRs according to the CA and HCA settings. To answer this question, we assessed the prevalence of resistance to different antibiotics usually recommended for urinary tract infections (UTIs) in the general population. METHODS: Observational, retrospective, multicenter study covering all episodes of AGPN occurring in hospitalized KTRs in 2019. RESULTS: A total of 210 patients were included in 7 centers and 244 episodes of AGPN were analyzed (158 CA-AGPN and 86 HCA-AGPN). The prevalence of 3GC and fluoroquinolone resistance was 23 % (n = 36) and 30 % (n = 50) in CA infections (n = 158), and 47 % (n = 40) and 31 % (n = 27) in HCA infections (n = 86), respectively. Cefepime resistance rate was 19 % (n = 30) in CA-AGPN and 29 % (n = 25) in HCA-AGPN. Piperacillin-tazobactam combination had resistance rates > 15 % in both CA and HCA infections. The only antimicrobials with resistance rates < 10 % were aminoglycosides and carbapenems. CONCLUSION: None of the antibiotics recommended in empirical treatment in UTIs has shown a resistance rate of less than 10% with regard to AGPN. Therefore, none of them should be used as monotherapy. A combination therapy including amikacin could be an appropriate strategy in this setting.


Asunto(s)
Antibacterianos , Trasplante de Riñón , Pielonefritis , Humanos , Estudios Retrospectivos , Antibacterianos/uso terapéutico , Pielonefritis/tratamiento farmacológico , Masculino , Femenino , Persona de Mediana Edad , Trasplante de Riñón/efectos adversos , Adulto , Enfermedad Aguda , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Infecciones Urinarias/tratamiento farmacológico , Combinación Piperacilina y Tazobactam/uso terapéutico , Anciano , Fluoroquinolonas/uso terapéutico , Cefalosporinas/uso terapéutico , Farmacorresistencia Bacteriana , Pruebas de Sensibilidad Microbiana , Infección Hospitalaria/tratamiento farmacológico
2.
Soins Gerontol ; 29(167): 38-45, 2024.
Artículo en Francés | MEDLINE | ID: mdl-38677810

RESUMEN

Nearly two-thirds of geriatric short-stay patients were eligible for pneumococcal vaccination. Among patients eligible for vaccination, less than 5 % had received at least one injection of pneumococcal vaccine on admission. We found no modifiable factors associated with vaccination status, but several avenues for improving vaccination coverage.


Asunto(s)
Infecciones Neumocócicas , Vacunas Neumococicas , Humanos , Vacunas Neumococicas/administración & dosificación , Vacunas Neumococicas/uso terapéutico , Anciano , Masculino , Femenino , Anciano de 80 o más Años , Infecciones Neumocócicas/prevención & control , Francia , Vacunación/estadística & datos numéricos , Cobertura de Vacunación/estadística & datos numéricos
3.
Microbiol Spectr ; 11(3): e0419022, 2023 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-37133395

RESUMEN

The choice of the best probabilistic postoperative antibiotics in bone and joint infections (BJIs) is still challenging. Since the implementation of protocolized postoperative linezolid in six French referral centers, linezolid-resistant multidrug-resistant Staphylococcus epidermidis (LR-MDRSE) strains were isolated in patients with BJI. We aimed here to describe clinical, microbiological, and molecular patterns associated with these strains. All patients with at least one intraoperative specimen positive for LR-MDRSE between 2015 and 2020 were included in this retrospective multicenter study. Clinical presentation, management, and outcome were described. LR-MDRSE strains were investigated by MIC determination for linezolid and other anti-MRSA antibiotics, characterization of genetic determinants of resistance, and phylogenetic analysis. Forty-six patients (colonization n = 10, infection n = 36) were included in five centers, 45 had prior exposure to linezolid, 33 had foreign devices. Clinical success was achieved for 26/36 patients. Incidence of LR-MDRSE increased over the study period. One hundred percent of the strains were resistant to oxazolidinones, gentamicin, clindamycin, ofloxacin, rifampicin, ceftaroline, and ceftobiprole, and susceptible to cyclins, daptomycin, and dalbavancin. Susceptibility to delafloxacin was bimodal. Molecular analysis was performed for 44 strains, and the main mutation conferring linezolid resistance was the 23S rRNA G2576T mutation. All strains belonged to the sequence type ST2 or its clonal complex, and phylogenetic analysis showed emergence of five populations corresponding geographically to the centers. We showed the emergence of new clonal populations of highly linezolid-resistant S. epidermidis in BJIs. Identifying patients at risk for LR-MDRSE acquisition and proposing alternatives to systematic postoperative linezolid use are essential. IMPORTANCE The manuscript describes the emergence of clonal linezolid-resistant strains of Staphylococcus epidermidis (LR-MDRSE) isolated from patients presenting with bone and joint infections. Incidence of LR-MDRSE increased over the study period. All strains were highly resistant to oxazolidinones, gentamicin, clindamycin, ofloxacin, rifampicin, ceftaroline, and ceftobiprole, but were susceptible to cyclins, daptomycin, and dalbavancin. Susceptibility to delafloxacin was bimodal. The main mutation conferring linezolid resistance was the 23S rRNA G2576T mutation. All strains belonged to the sequence type ST2 or its clonal complex, and phylogenetic analysis showed emergence of five populations corresponding geographically to the centers. LR-MDRSE bone and joint infections seem to be accompanied by an overall poor prognosis related to comorbidities and therapeutic issues. Identifying patients at risk for LR-MDRSE acquisition and proposing alternatives to systematic postoperative linezolid use become essential, with a preference for parenteral drugs such as lipopeptids or lipoglycopeptids.


Asunto(s)
Daptomicina , Staphylococcus aureus Resistente a Meticilina , Oxazolidinonas , Infecciones Estafilocócicas , Humanos , Linezolid/farmacología , Linezolid/uso terapéutico , Staphylococcus epidermidis/genética , Rifampin/uso terapéutico , Clindamicina/uso terapéutico , ARN Ribosómico 23S/genética , Filogenia , Proteína 1 Similar al Receptor de Interleucina-1/genética , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Gentamicinas/uso terapéutico , Ofloxacino , Pruebas de Sensibilidad Microbiana , Farmacorresistencia Bacteriana/genética , Ceftarolina
5.
Microbiol Spectr ; 10(2): e0232921, 2022 04 27.
Artículo en Inglés | MEDLINE | ID: mdl-35357222

RESUMEN

Bone and joint infections (BJI) represent the second cause of invasive Group B Streptococcus (GBS) infections. Biofilm formation plays a major role in BJI. This study's aim was to analyze the genetic features and biofilm production of GBS strains. In six French laboratories, 77 GBS strains isolated from BJI and 57 strains from vaginal human colonization (Hcol) were characterized and compared by Multi-Locus Sequence Typing (MLST). PCR was used to search for the adhesins (bsaB, lmb, scpB, fbsA, fbsB, hvgA, bibA, bca, srr-1, and srr-2) and Pilus Islands (PI) related genes (PI-1, PI-2a, PI-2b). Biofilm production was studied by crystal violet assay. Strains were categorized into three groups, based on Specific Biofilm Formation (SBF) values defined as: weak, moderate, or strong producers. Molecular study revealed three major clonal complexes (CC) in BJI strains: CC1 (42%), CC23 (22%) and CC10 (14%). Several associations between CC and adhesin/pili were identified: CC1 with srr2, PI-1 + 2a; CC10 with srr-1, bca, PI-1 + 2a; CC17 with fbsB, hvgA, srr-2, PI-1+PI-2b; CC19 with bibA, srr-1, PI-1 + 2a; CC23 with fbsB, bibA, srr-1, PI-2a. The biofilm production was significantly different according to CC, adhesins and pili gene detection. CC10, CC23 and strains harboring fbsB produce more biofilm than CC1, PI-1 + 2a (independently). Finally, SBF values were significantly stronger for Hcol strains rather than for BJI strains (76% versus 40%). This study revealed that Hcol strains appeared to produce stronger biofilm than BJI strains, though they belonged to similar CCs and had the same adhesin and pili content. IMPORTANCE Bone and joint infections (BJI) are pathologies that can be life-threatening and result in compromised functional prognosis for patients. Relapses are common and often related to biofilm formation. Group B streptococci (GBS) BJI increased since the last decade. However, few data are available on this subject in the literature. Our study aims to highlight genotype and biofilm production of GBS isolates from BJI. Seventy-seven GBS strains isolated from BJI and 57 from asymptomatic human vaginal colonization were characterized by multilocus sequence typing (MLST), adhesins content, nature of the pili and the ability to form biofilm. Our results revealed that vaginal human colonization strains produced stronger biofilm than BJI strains, despite belonging to the same phylogenetic lineage and having the same adhesin and pili content.


Asunto(s)
Infecciones Estreptocócicas , Streptococcus agalactiae , Adhesinas Bacterianas/genética , Biopelículas , Femenino , Genotipo , Humanos , Tipificación de Secuencias Multilocus , Filogenia , Streptococcus agalactiae/genética
6.
Microorganisms ; 9(12)2021 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-34946075

RESUMEN

Bacteria belonging to the genus Achromobacter are increasingly isolated from respiratory samples of people with cystic fibrosis (PWCF). The management of this multidrug-resistant genus is challenging and characterised by a lack of international recommendations, therapeutic guidelines and data concerning antibiotic susceptibility, especially concerning the newer antibiotics. The objective of this study was to describe the antibiotic susceptibility of Achromobacter isolates from PWCF, including susceptibility to new antibiotics. The minimum inhibitory concentrations (MICs) of 22 antibiotics were determined for a panel of 23 Achromobacter isolates from 19 respiratory samples of PWCF. Two microdilution MIC plates were used: EUMDROXF® plate (Sensititre) and Micronaut-S Pseudomonas MIC® plate (Merlin) and completed by a third method if necessary (E-test® or UMIC®). Among usual antimicrobial agents, the most active was imipenem (70% susceptibility). Trimethoprim-sulfamethoxazole, piperacillin and tigecycline (65%, 56% and 52% susceptibility, respectively) were still useful for the treatment of Achromobacter infections. Among new therapeutic options, ß-lactams combined with a ß-lactamase-inhibitor did not bring benefits compared to ß-lactam alone. On the other hand, cefiderocol appeared as a promising therapeutic alternative for managing Achromobacter infections in PWCF. This study provides the first results on the susceptibility of clinical Achromobacter isolates concerning new antibiotics. More microbiological and clinical data are required to establish the optimal treatment of Achromobacter infections.

8.
J Clin Med ; 8(12)2019 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-31810267

RESUMEN

Currently, no guideline provides recommendations on the duration of empirical antimicrobial treatment (EAT) in prosthetic joint infection (PJI). The aim of our study was to describe the time to growth of bacteria involved in PJI, rendering possible decreased duration of EAT. Based on a French multicentre prospective cohort study, culture data from patients with confirmed hip or knee PJI were analysed. For each patient, five samples were processed. Time to positivity was defined as the first positive medium in at least one sample for virulent pathogens and as the first positive medium in at least two samples for commensals. Definitive diagnosis of polymicrobial infections was considered the day the last bacteria were identified. Among the 183 PJIs, including 28 polymicrobial infections, microbiological diagnosis was carried out between Day 1 (D1) and D5 for 96.7% of cases. There was no difference in the average time to positivity between acute and chronic PJI (p = 0.8871). Microbiological diagnosis was given earlier for monomicrobial than for polymicrobial infections (p = 0.0034). When an optimized culture of peroperative samples was carried out, almost all cases of PJI were diagnosed within five days, including polymicrobial infections. EAT can be re-evaluated at D5 according to microbiological documentation.

11.
Eur J Clin Microbiol Infect Dis ; 38(9): 1659-1663, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31203474

RESUMEN

Prosthetic joint infection (PJI) can occur with a wide range of microorganisms and clinical features. After replacement surgery of prosthetic joint, prescription of probabilistic broad-spectrum antimicrobial therapy is usual, while awaiting microbial culture results. The aim of our study was to describe the antibiotic susceptibility of microorganisms isolated from hip and knee PJI. The data were collected to determine the best alternative to the usual combination of piperacillin-tazobactam (TZP) or cefotaxime (CTX) and vancomycin (VAN). Based on a French prospective, multicenter study, we analyzed microbiological susceptibility to antibiotics of 183 strains isolated from patients with confirmed hip or knee PJI. In vitro susceptibility was evaluated: TZP+VAN, TZP+linezolid (LZD), CTX+VAN, and CTX+LZD. We also analyzed resistance to different antibiotics commonly used as oral alternatives. Among the 183 patients with PJI, 62 (34%) had a total knee prosthesis, and 121 (66%) a hip prosthesis. The main identified bacteria were Staphylococcus aureus (32.2% of isolates), coagulase-negative staphylococci (27.3%), Enterobacteriaceae (14.2%), and Streptococcus (13.7%). Infections were polymicrobial for 28 (15.3%) patients. All combinations were highly effective: CTX+VAN, CTX+LZD, TZP+VAN, and TZP+LZD (93.4%, 94%, 98.4%, and 98.9% of all cases respectively). Use of LZD instead of VAN in combination with a broad-spectrum beta-lactam covers almost all of the bacteria isolated in PJI. This association should be considered in probabilistic chemotherapy, as it is particularly easy to use (oral administration and no vancomycin monitoring).


Asunto(s)
Antibacterianos/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Prótesis de la Rodilla/microbiología , Linezolid/uso terapéutico , Infecciones Relacionadas con Prótesis/tratamiento farmacológico , Anciano , Anciano de 80 o más Años , Artritis Infecciosa/tratamiento farmacológico , Artroplastia de Reemplazo de Cadera/efectos adversos , Artroplastia de Reemplazo de Rodilla/efectos adversos , Bacterias/efectos de los fármacos , Infecciones Bacterianas/microbiología , Estudios Transversales , Femenino , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Probabilidad , Estudios Prospectivos , Infecciones Relacionadas con Prótesis/microbiología
12.
J Clin Microbiol ; 56(9)2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29976593

RESUMEN

No gold standard exists for histopathological diagnosis of a prosthetic joint infection (PJI). The historical criterion considers the presence of neutrophil infiltration upon examination of periprosthetic tissue. Morawietz et al. proposed a classification of periprosthetic membranes (Morawietz et al., Clin Pathol 59:591-597, 2006, https://doi.org/10.1136/jcp.2005.027458) and a more recently described classification with a new cutoff value of 23 neutrophils in 10 high-power fields (Morawietz et al., Histopathology 54:847-853, 2009. https://doi.org/10.1111/j.1365-2559.2009.03313.x). We performed a multicenter prospective study, which compared both methods for the diagnosis of PJI. All suspicions of PJI (n = 264) between December 2010 and March 2012 in seven centers were prospectively included. Five perioperative specimens were collected per patient for cultures, and one was collected for histology. Diagnosis of PJI was made according to the Infectious Diseases Society of America (IDSA) guidelines. Histopathological analysis classified the patients according to the threshold of 23 neutrophils and according to the classification of Morawietz. Performances of both methods were compared by using clinical and/or bacteriological criteria as the gold standard. Among 264 patients with suspected PJI, a diagnosis of infection was confirmed in 215 and unconfirmed in 49 patients. Histopathological analysis was available for 150 confirmed PJI and 40 unconfirmed PJI cases. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 78.7%, 90.0%, 96.7%, 52.9%, and 81.1%, respectively, for the Morawietz classification, and 82.0%, 90.0%, 96.9%, 57.1%, and 83.7%, respectively, for the 23-neutrophil threshold. The new algorithm using a threshold of 23 neutrophils can be proposed as a new gold standard for the histopathological diagnosis of PJI.


Asunto(s)
Artritis Infecciosa/diagnóstico , Interfase Hueso-Implante/patología , Prótesis Articulares , Neutrófilos/patología , Infecciones Relacionadas con Prótesis/diagnóstico , Anciano , Artritis Infecciosa/patología , Técnicas Bacteriológicas , Femenino , Humanos , Recuento de Leucocitos , Masculino , Estudios Prospectivos , Infecciones Relacionadas con Prótesis/patología , Sensibilidad y Especificidad
13.
J Antimicrob Chemother ; 73(9): 2352-2359, 2018 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-29897463

RESUMEN

Objectives: There is an urgent need for accurate and fast diagnostic tests to identify carbapenemase-producing bacteria. Here, we have evaluated three MALDI-TOF-based techniques to detect carbapenemase-producing Enterobacteriaceae (CPE) from cultured colonies. Methods: The performance of three MALDI-TOF-based techniques, including the commercialized MBT STAR®-Carba IVD Kit (Bruker Daltonics) and two in-house protocols performed on the Microflex LT Biotyper (Bruker Daltonics) and the VITEK® MS Plus (bioMérieux), were compared with those of the RAPIDEC® CARBA NP (bioMérieux). A collection of 175 isolates including 120 carbapenemase producers and 55 non-carbapenemase producers was tested. Samples were tested blind in the three participating centres. The repeatability of the MBT STAR®-Carba IVD Kit was also evaluated. Results: The three MALDI-TOF techniques possess sensitivities ranging from 95% to 100% and specificities from 98.2% to 100% compared with 99.2% and 100%, respectively, for the RAPIDEC® CARBA NP. The MBT STAR®-Carba IVD Kit gave highly reproducible results and is the only technique able to provide a concomitant identification of the bacterial isolate. The three MALDI-TOF techniques possess a fast turnaround time (less than 1.5 h). Conclusions: Overall, MALDI-TOF is a reliable technique for the rapid detection of CPE from cultured colonies. MBT STAR®-Carba IVD Kit, the only commercially available assay, could easily be implemented in a clinical microbiology laboratory if it is already equipped with a Microflex LT Biotyper mass spectrometer.


Asunto(s)
Técnicas Bacteriológicas/métodos , Enterobacteriaceae Resistentes a los Carbapenémicos/aislamiento & purificación , Pruebas Diagnósticas de Rutina/métodos , Infecciones por Enterobacteriaceae/diagnóstico , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Enterobacteriaceae Resistentes a los Carbapenémicos/enzimología , Infecciones por Enterobacteriaceae/microbiología , Humanos , Sensibilidad y Especificidad , Factores de Tiempo
14.
Infect Dis (Lond) ; 50(7): 539-549, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29451055

RESUMEN

INTRODUCTION: Immediate empirical antibiotic therapy is mandatory in febrile chemotherapy-induced neutropenia, but its optimal duration is unclear, especially in patients with fever of unknown origin (FUO). OBJECTIVES: The primary objective of this 20-month prospective observational study was to evaluate the feasibility and safety of short-term antibiotic treatment in afebrile or febrile patients exhibiting FUO, irrespective of their neutrophil count. The secondary objective was to describe the epidemiology of all episodes of febrile neutropenia. METHODS: In the first phase of the study, empirical antibiotic therapy in FUO patients was stopped after 48 h of apyrexia, in accordance with European Conference on Infections in Leukaemia guidelines (n = 45). In the second phase of the study, antibiotics were stopped no later than day 5 for all FUO patients, regardless of body temperature or leukocyte count (n = 37). RESULTS: Two hundred and thirty-eight cases of febrile neutropenia in 123 patients were included. Neither the composite endpoint (p = .11), nor each component (in-hospital mortality (p = .80), intensive care unit admission (p = 0.48), relapse of infection ≤48 h after discontinuation of antibiotics (p = .82)) differed between the two FUO groups. Violation of protocol occurred in 17/82 episodes of FUO without any major impact on statistical results. Twenty-six (57.3%) and 22 (59.5%) FUO episodes did not relapse during hospital-stay (p = 1), and nine (20%) and five (13.5%) presented another FUO, respectively. One hundred and fifty-six episodes of febrile neutropenia (65.5%) were clinically or microbiologically documented, including 85 bacteremia. CONCLUSIONS: These results suggest that early discontinuation of empirical antibiotics in FUO is safe for afebrile neutropenic patients.


Asunto(s)
Antibacterianos/administración & dosificación , Neutropenia Febril/tratamiento farmacológico , Fiebre de Origen Desconocido/tratamiento farmacológico , Privación de Tratamiento , Adolescente , Adulto , Anciano , Antibacterianos/efectos adversos , Antibacterianos/uso terapéutico , Neutropenia Febril Inducida por Quimioterapia/tratamiento farmacológico , Neutropenia Febril Inducida por Quimioterapia/epidemiología , Quimioterapia Combinada , Estudios de Factibilidad , Neutropenia Febril/epidemiología , Neutropenia Febril/mortalidad , Femenino , Fiebre de Origen Desconocido/epidemiología , Fiebre de Origen Desconocido/mortalidad , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Infecciones por Bacterias Gramnegativas/epidemiología , Infecciones por Bacterias Gramnegativas/mortalidad , Humanos , Masculino , Persona de Mediana Edad , Guías de Práctica Clínica como Asunto , Estudios Prospectivos , Seguridad , Factores de Tiempo , Adulto Joven
15.
J Antimicrob Chemother ; 72(9): 2469-2477, 2017 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-28859446

RESUMEN

Objectives: To describe a novel plasmid-borne class D carbapenemase (CHDL) named OXA-427 identified in several Enterobacteriaceae clinical isolates from nine patients in one Belgian hospital. Methods: OXA-427-producing isolates were analysed by an electrochemical imipenem hydrolysis method (BYG Carba test), Carba NP test, conventional phenotypic assays and by molecular methods (PCR, whole sequencing of the OXA-427-encoding plasmid and cloning). The antimicrobial resistance profile of OXA-427 was analysed by expression of the cloned gene in Escherichia coli DH10B and J53. Results: Eleven OXA-427-producing Enterobacteriaceae isolates of various species were identified from clinical specimens of nine patients between March 2012 and June 2014. OXA-427 shares only 22%-29% amino acid identity with OXA-48-like enzymes and other acquired CHDL (e.g. OXA-23, -24/40 and -58 of Acinetobacter spp.). Conversely, it appeared closely related to the chromosomal class D ß-lactamase of Aeromonas media, Aeromonas hydrophila and Aeromonas sobria (99%, 89% and 77% of identity, respectively). When expressed in E. coli, OXA-427 hydrolysed imipenem and conferred resistance to extended-spectrum cephalosporins (mostly ceftazidime), penicillins including temocillin, and reduced susceptibility to carbapenems. The blaOXA-427 gene was located in a 45 kb resistance island on a 177 kb IncA/C plasmid. Conclusions: OXA-427 is a novel CHDL most closely related to chromosomal class D ß-lactamase of A. media WS. It confers resistance to penicillins, ceftazidime and aztreonam and in some instances to carbapenems. OXA-427, which is not detectable by classical molecular tests, caused a protracted outbreak in one university hospital over a 2 year period.


Asunto(s)
Antibacterianos/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Carbapenémicos/metabolismo , Infecciones por Enterobacteriaceae/microbiología , Enterobacteriaceae/enzimología , Plásmidos/genética , beta-Lactamasas/genética , beta-Lactamasas/metabolismo , Antibacterianos/farmacología , Proteínas Bacterianas/aislamiento & purificación , Bélgica/epidemiología , Carbapenémicos/farmacología , Clonación Molecular , Farmacorresistencia Bacteriana Múltiple/genética , Infecciones por Enterobacteriaceae/epidemiología , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Hidrólisis , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , beta-Lactamasas/aislamiento & purificación
17.
J Clin Microbiol ; 54(2): 385-91, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26637380

RESUMEN

Although numerous perioperative samples and culture media are required to diagnose prosthetic joint infection (PJI), their exact number and types have not yet been definitely determined with a high level of proof. We conducted a prospective multicenter study to determine the minimal number of samples and culture media required for accurate diagnosis of PJI. Over a 2-year period, consecutive patients with clinical signs suggesting PJI were included, with five perioperative samples per patient. The bacteriological and PJI diagnosis criteria were assessed using a random selection of two, three, or four samples and compared with those obtained using the recommended five samples (references guidelines). The results obtained with two or three culture media were then compared with those obtained with five culture media for both criteria. The times-to-positivity of the different culture media were calculated. PJI was confirmed in 215/264 suspected cases, with a bacteriological criterion in 192 (89%). The PJI was monomicrobial (85%) or polymicrobial (15%). Percentages of agreement of 98.1% and 99.7%, respectively, for the bacteriological criterion and confirmed PJI diagnosis were obtained when four perioperative samples were considered. The highest percentages of agreement were obtained with the association of three culture media, a blood culture bottle, a chocolate agar plate, and Schaedler broth, incubated for 5, 7, and 14 days, respectively. This new procedure leads to significant cost saving. Our prospective multicenter study showed that four samples seeded on three culture media are sufficient for diagnosing PJI.


Asunto(s)
Artritis/diagnóstico , Artritis/microbiología , Infecciones Relacionadas con Prótesis/diagnóstico , Infecciones Relacionadas con Prótesis/microbiología , Técnicas Bacteriológicas/métodos , Estudios Transversales , Femenino , Costos de la Atención en Salud , Humanos , Masculino , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Factores de Tiempo
18.
J Clin Microbiol ; 53(7): 2163-71, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25926485

RESUMEN

The recognition of carbapenemase-producing Enterobacteriaceae (CPE) isolates is a major laboratory challenge, and their inappropriate or delayed detection may have negative impacts on patient management and on the implementation of infection control measures. We describe here a matrix-assisted laser desorption ionization-time of flight (MALDI-TOF)-based method to detect carbapenemase activity in Enterobacteriaceae. After a 20-min incubation of the isolate with 0.5 mg/ml imipenem at 37°C, supernatants were analyzed by MALDI-TOF in order to identify peaks corresponding to imipenem (300 Da) and an imipenem metabolite (254 Da). A total of 223 strains, 77 CPE (OXA-48 variants, KPC, NDM, VIM, IMI, IMP, and NMC-A) and 146 non-CPE (cephalosporinases, extended-spectrum ß-lactamases [ESBLs], and porin defects), were tested and used to calculate a ratio of imipenem hydrolysis: mass spectrometry [MS] ratio = metabolite/(imipenem + metabolite). An MS ratio cutoff was statistically determined to classify strains as carbapenemase producers (MS ratio of ≥0.82). We validated this method first by testing 30 of our 223 isolates (15 CPE and 15 non-CPE) 10 times to calculate an intraclass correlation coefficient (ICC of 0.98), showing the excellent repeatability of the method. Second, 43 strains (25 CPE and 18 non-CPE) different from the 223 strains used to calculate the ratio cutoff were used as external controls and blind tested. They yielded sensitivity and specificity of 100%. The total cost per test is <0.10 U.S. dollars (USD). This easy-to-perform assay is time-saving, cost-efficient, and highly reliable and might be used in any routine laboratory, given the availability of mass spectrometry, to detect CPE.


Asunto(s)
Proteínas Bacterianas/análisis , Técnicas Bacteriológicas/métodos , Enterobacteriaceae/enzimología , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , beta-Lactamasas/análisis , Antibacterianos/metabolismo , Humanos , Hidrólisis , Imipenem/metabolismo , Sensibilidad y Especificidad , Factores de Tiempo
19.
Antimicrob Agents Chemother ; 59(7): 3823-8, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25870062

RESUMEN

The epidemiology of carbapenemases worldwide is showing that OXA-48 variants are becoming the predominant carbapenemase type in Enterobacteriaceae in many countries. However, not all OXA-48 variants possess significant activity toward carbapenems (e.g., OXA-163). Two Serratia marcescens isolates with resistance either to carbapenems or to extended-spectrum cephalosporins were successively recovered from the same patient. A genomic comparison using pulsed-field gel electrophoresis and automated Rep-PCR typing identified a 97.8% similarity between the two isolates. Both strains were resistant to penicillins and first-generation cephalosporins. The first isolate was susceptible to expanded-spectrum cephalosporins, was resistant to carbapenems, and had a significant carbapenemase activity (positive Carba NP test) related to the expression of OXA-48. The second isolate was resistant to expanded-spectrum cephalosporins, was susceptible to carbapenems, and did not express a significant imipenemase activity, (negative for the Carba NP test) despite possessing a blaOXA-48-type gene. Sequencing identified a novel OXA-48-type ß-lactamase, OXA-405, with a four-amino-acid deletion compared to OXA-48. The blaOXA-405 gene was located on a ca. 46-kb plasmid identical to the prototype IncL/M blaOXA-48-carrying plasmid except for a ca. 16.4-kb deletion in the tra operon, leading to the suppression of self-conjugation properties. Biochemical analysis showed that OXA-405 has clavulanic acid-inhibited activity toward expanded-spectrum activity without significant imipenemase activity. This is the first identification of a successive switch of catalytic activity in OXA-48-like ß-lactamases, suggesting their plasticity. Therefore, this report suggests that the first-line screening of carbapenemase producers in Enterobacteriaceae may be based on the biochemical detection of carbapenemase activity in clinical settings.


Asunto(s)
Antibacterianos/uso terapéutico , Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana Múltiple/genética , Infecciones por Serratia/tratamiento farmacológico , Serratia marcescens/efectos de los fármacos , beta-Lactamasas/genética , Adulto , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Secuencia de Bases , Carbapenémicos/uso terapéutico , Cefalosporinas/uso terapéutico , ADN Bacteriano/genética , Femenino , Humanos , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Plásmidos/genética , Análisis de Secuencia de ADN , Infecciones por Serratia/microbiología , Serratia marcescens/genética , Serratia marcescens/aislamiento & purificación , beta-Lactamasas/química , beta-Lactamasas/metabolismo
20.
J Clin Microbiol ; 53(2): 419-24, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25411177

RESUMEN

The objective of this study was to assess the performance of seven French laboratories for 16S rRNA gene detection by real-time PCR in the diagnosis of bone and joint infection (BJI) to validate a large multicenter study. External quality control (QC) was required owing to the differences in extraction procedures and the molecular equipment used in the different laboratories. Three proficiency sets were organized, including four bacterial DNA extracts and four bead mill-pretreated osteoarticular specimens. Extraction volumes, 16S rRNA gene primers, and sequencing interpretation rules were standardized. In order to assess each laboratory's ability to achieve the best results, scores were assigned, and each QC series was classified as optimal, acceptable, or to be improved. A total of 168 QCs were sent, and 160 responses were analyzed. The expected results were obtained for 93.8%, with the same proportion for extracts (75/80) and clinical specimens (75/80). For the specimens, there was no significant difference between manual and automated extraction. This QC demonstrated the ability to achieve good and homogeneous results using the same 16S rRNA gene PCR with different equipment and validates the possibility of high-quality multicenter studies using molecular diagnosis for BJI.


Asunto(s)
Infecciones Bacterianas/diagnóstico , Infecciones Bacterianas/microbiología , Ensayos de Aptitud de Laboratorios , Técnicas de Diagnóstico Molecular/métodos , Osteoartritis/diagnóstico , Osteoartritis/microbiología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , ADN Ribosómico/genética , Francia , Genes de ARNr , Humanos , ARN Ribosómico 16S/genética
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