Posts filed under ‘Resistencia bacteriana’

Complicated Urinary Tract Infections: What’s a Lab To Do?

Journal of Clinical Microbiology May 2016 V.54 N.5 P.1189-1190

Stephen M. Brecher

aDepartment of Pathology and Laboratory Medicine, VA Boston HealthCare System, West Roxbury, Massachusetts, USA

bDepartment of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, USA

The article by Price et al. in this issue (T. K. Price et al., J Clin Microbiol 54:1216–1222, 2016, http://dx.doi.org/10.1128/JCM.00044-16) advocates for the use of a larger inoculum when culturing urine obtained by “in-and-out” catheterization in a selected female population.

Their findings and the resulting challenges will afford clinical microbiologists and specialty physicians an opportunity to review what will or should be done with the additional microbiological culture data.

PDF

http://jcm.asm.org/content/54/5/1189.full.pdf

April 29, 2016 at 2:38 pm

Rethinking the Definition of Success in the Management of a Periprosthetic Joint Infection

The Journal of Bone & Joint Surgery SEPT.16, 2015 V.97 N.18 e64

Commentary on an article by Miguel M. Gomez, MD, et al.: “The Fate of Spacers in the Treatment of Periprosthetic Joint Infection”

 

In the article “The Fate of Spacers in the Management of Periprosthetic Joint Infection,” Gomez et al. raise two important questions with regard to the treatment of periprosthetic joint infection: What occurs with the patient during the interim between staged surgical treatments; and what occurs with the patient who does not undergo the subsequent stage of treatment?

This information is valuable as most reports on the outcome of a two-stage treatment for periprosthetic joint infection, in which infection eradication is attained in 85% to 90% of patients, have focused on showing results only for patients who completed the second stage. From their findings, Gomez et al. suggest that this may overestimate the rate of infection eradication, as some of these treated patients may have a subsequent infection. Equally importantly, the point is made that there are other possible outcomes after the index removal of the implant (failure to proceed with the second stage, surgical treatment other than reimplantation, amputation, fusion, resection arthroplasty, spacer retention, and death) that need to be described. The combination of reporting the success of the two-stage treatment and reporting the failures as defined above yields a much fuller picture of the impact of a periprosthetic joint infection. The authors are to be commended for asking and attempting to answer questions of great clinical import and in expanding the criteria for what defines a successful outcome….

 

abstract

http://jbjs.org/content/97/18/e64

 

PDF

http://jbjs.org/content/jbjsam/97/18/e64.full.pdf

April 29, 2016 at 2:37 pm

First Report of cfr-Carrying Plasmids in the Pandemic Sequence Type 22 Methicillin-Resistant Staphylococcus aureus Staphylococcal Cassette Chromosome mec Type IV Clone

Antimicrobial Agents and Chemotherapy May 2016 V.60  N.5 P.3007-3015

Anna C. Shore, Alexandros Lazaris, Peter M. Kinnevey, Orla M. Brennan, Gráinne I. Brennan, Brian O’Connell, Andrea T. Feßler, Stefan Schwarz, and David C. Coleman

aMicrobiology Research Unit, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland

bNational MRSA Reference Laboratory, St. James’s Hospital, Dublin, Ireland

cDepartment of Clinical Microbiology, School of Medicine, Trinity College Dublin, St. James’s Hospital, Dublin, Ireland

dInstitute of Farm Animal Genetics, Friedrich Loeffler Institut, Neustadt-Mariensee, Germany

Linezolid is often the drug of last resort for serious methicillin-resistant Staphylococcus aureus (MRSA) infections. Linezolid resistance is mediated by mutations in 23S rRNA and genes for ribosomal proteins; cfr, encoding phenicol, lincosamide, oxazolidinone, pleuromutilin, and streptogramin A (PhLOPSA) resistance; its homologue cfr(B); or optrA, conferring oxazolidinone and phenicol resistance.

Linezolid resistance is rare in S. aureus, and cfr is even rarer. This study investigated the clonality and linezolid resistance mechanisms of two MRSA isolates from patients in separate Irish hospitals. Isolates were subjected to cfr PCR, PhLOPSA susceptibility testing, 23S rRNA PCR and sequencing, DNA microarray profiling, spa typing, pulsed-field gel electrophoresis (PFGE), plasmid curing, and conjugative transfer.

Whole-genome sequencing was used for single-nucleotide variant (SNV) analysis, multilocus sequence typing, L protein mutation identification, cfr plasmid sequence analysis, and optrA and cfr(B) detection.

Isolates M12/0145 and M13/0401 exhibited linezolid MICs of 64 and 16 mg/liter, respectively, and harbored identical 23S rRNA and L22 mutations, but M12/0145 exhibited the mutation in 2/6 23S rRNA alleles, compared to 1/5 in M13/0401.

Both isolates were sequence type 22 MRSA staphylococcal cassette chromosome mec type IV (ST22-MRSA-IV)/spa type t032 isolates, harbored cfr, exhibited the PhLOPSA phenotype, and lacked optrA and cfr(B).

They differed by five PFGE bands and 603 SNVs. Isolate M12/0145 harbored cfr and fexA on a 41-kb conjugative pSCFS3-type plasmid, whereas M13/0401 harbored cfr and lsa(B) on a novel 27-kb plasmid.

This is the first report of cfr in the pandemic ST22-MRSA-IV clone. Different cfr plasmids and mutations associated with linezolid resistance in genotypically distinct ST22-MRSA-IV isolates highlight that prudent management of linezolid use is essential.

PDF

http://aac.asm.org/content/60/5/3007.full.pdf

April 28, 2016 at 8:23 am

Staphylococcus aureus resistentes a la meticilina portadores del gen mecC: ¿un problema emergente?

Enf Inf & Microb Clinica Mayo 2016 V.34 N.05 P.277-9

Editorial

Ana Vindel, Emilia Cercenado

a Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, España

b Departamento de Medicina, Facultad de Medicina, Universidad Complutense, Madrid, España

c Servicio de Microbiología y Enfermedades Infecciosas, Hospital General Universitario Gregorio Marañón, Madrid, España

Staphylococcus aureus (S. aureus) resistente a la meticilina –SARM– es un importante patógeno humano que causa una amplia variedad de infecciones que pueden ser leves, como algunas infecciones de piel y partes blandas, o graves, como bacteriemia, endocarditis, neumonía e infecciones de localización quirúrgica.

Además puede producir una colonización asintomática, lo que facilita su transmisión y diseminación. Desde su descripción inicial en 1959 y durante varias décadas, el SARM se había considerado un patógeno confinado al ámbito sanitario, pero a partir de la década de los noventa, se describe la emergencia de cepas de SARM responsables de infecciones aparentemente adquiridas en la comunidad.

Las cepas comunitarias pertenecían a clones diferentes a los implicados en las infecciones adquiridas en centros sanitarios, muchas de ellas producían la leucocidina de Panton-Valentine y eran más sensibles a los antibióticos antiestafilocócicos, si bien, actualmente estas diferencias se han difuminado y no son absolutas.

Por otra parte, en las últimas décadas se comunica la emergencia de SARM como un patógeno que también puede colonizar e infectar a un amplio rango de especies animales, tanto de granjas, como de compañía o salvajes.

Estas cepas, pertenecientes a otros linajes genéticos diferentes se conocen como SARM asociados al ganado1, 2. Las cepas de SAMR en animales no solo son importantes desde el punto de vista de la salud animal y desde la perspectiva económica sino que también pueden actuar como reservorio zoonótico, entrar en la cadena alimentaria y causar infecciones en humanos.

En todas estas cepas, la resistencia de S. aureus a la meticilina, se debe a la producción de una nueva proteína, la PBP2a, que presenta una baja afinidad por los betalactámicos. Esta proteína está codificada por el gen mecA….

PDF

http://apps.elsevier.es/watermark/ctl_servlet?_f=10&pident_articulo=90452006&pident_usuario=0&pcontactid=&pident_revista=28&ty=17&accion=L&origen=zonadelectura&web=www.elsevier.es&lan=es&fichero=28v34n05a90452006pdf001.pdf

April 28, 2016 at 8:21 am

Caracterización molecular de Staphylococcus aureus en personas relacionadas con una granja de ganado en España, con la detección de SARM-CC130-mecC: ¿un caso de zoonosis?

Enf Inf & Microb Clinica Mayo 2016 V.34 N.05 P.280-5

Daniel Benito, Paula Gómez, Carmen Aspiroz, Myriam Zarazaga, Carmen Lozano, Carmen Torres

a Área Bioquímica y Biología Molecular, Universidad de La Rioja, 26006 Logroño, Spain

b Unidad de Microbiología. Hospital Royo Villanova, Zaragoza, Spain

Objetivo

Estudiar la presencia de S. aureus en muestras nasales y cutáneas de los miembros de una familia de granjeros, con distinto nivel de contacto con ganado, y caracterizar los aislados obtenidos.

Métodos

Se recogieron 3 muestras nasales (1 cada 6 meses) de los 11 miembros de la familia de granjeros (n = 31) y 9 muestras cutáneas de pequeñas lesiones de 5 de ellos, para aislamiento de S. aureus, tanto sensible (SASM) como resistente a meticilina (SARM). Se realizó la caracterización molecular de los aislados (spa- y multi-locus-sequence-typing) y se estudiaron sus fenotipos y genotipos de resistencia, y su contenido en genes de virulencia y del clúster de evasión-inmune-humano (IEC).

Resultados

Se obtuvieron 18 aislados de S. aureus (1 SARM y 17 SASM) en las 40 muestras estudiadas. De las personas examinadas, 9/11 fueron portadoras de S. aureus: 7/11 en muestras nasales y 4/5 en cutáneas. La cepa SARM fue aislada en una lesión cutánea de un granjero, portaba el gen mecC y se tipó como ST130-CC130-t843. En las 17 cepas SASM se detectaron 9 tipos de spa y 9 secuencias-tipo, adscritas a los complejos clonales CC2, CC30, CC45, CC121 y a los asociados con ganado CC9 y CC133. Seis cepas portaron los genes eta o tsst-1. Tres de las 18 cepas carecían de los genes del sistema de evasión inmune (IEC) (SARM-ST130, SASM-ST1333 y SASM-ST133), y el resto presentaron IEC-A o -B.

Conclusión

Se detectaron líneas genéticas de S. aureus asociadas a animales en la familia de granjeros, destacando la detección de SASM-CC133 y SARM-ST130-mecC.

PDF

http://apps.elsevier.es/watermark/ctl_servlet?_f=10&pident_articulo=90452007&pident_usuario=0&pcontactid=&pident_revista=28&ty=18&accion=L&origen=zonadelectura&web=www.elsevier.es&lan=en&fichero=28v34n05a90452007pdf001.pdf

 

April 28, 2016 at 8:18 am

Provision of social norm feedback to high prescribers of antibiotics in general practice: a pragmatic national randomised controlled trial

Lancet April 23, 2016 V.387 N.10029 P.1743–1752

Articles

Michael Hallsworth, Tim Chadborn, PhD, Anna Sallis, Michael Sanders, PhD, Daniel Berry, Felix Greaves, PhD, Lara Clements, Prof Sally C Davies, MD

Background

Unnecessary antibiotic prescribing contributes to antimicrobial resistance. In this trial, we aimed to reduce unnecessary prescriptions of antibiotics by general practitioners (GPs) in England.

Methods

In this randomised, 2 × 2 factorial trial, publicly available databases were used to identify GP practices whose prescribing rate for antibiotics was in the top 20% for their National Health Service (NHS) Local Area Team. Eligible practices were randomly assigned (1:1) into two groups by computer-generated allocation sequence, stratified by NHS Local Area Team. Participants, but not investigators, were blinded to group assignment. On Sept 29, 2014, every GP in the feedback intervention group was sent a letter from England’s Chief Medical Officer and a leaflet on antibiotics for use with patients. The letter stated that the practice was prescribing antibiotics at a higher rate than 80% of practices in its NHS Local Area Team. GPs in the control group received no communication. The sample was re-randomised into two groups, and in December, 2014, GP practices were either sent patient-focused information that promoted reduced use of antibiotics or received no communication. The primary outcome measure was the rate of antibiotic items dispensed per 1000 weighted population, controlling for past prescribing. Analysis was by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN32349954, and has been completed.

Findings

Between Sept 8 and Sept 26, 2014, we recruited and assigned 1581 GP practices to feedback intervention (n=791) or control (n=790) groups. Letters were sent to 3227 GPs in the intervention group. Between October, 2014, and March, 2015, the rate of antibiotic items dispensed per 1000 population was 126·98 (95% CI 125·68–128·27) in the feedback intervention group and 131·25 (130·33–132·16) in the control group, a difference of 4·27 (3·3%; incidence rate ratio [IRR] 0·967 [95% CI 0·957–0·977]; p<0·0001), representing an estimated 73 406 fewer antibiotic items dispensed. In December, 2014, GP practices were re-assigned to patient-focused intervention (n=777) or control (n=804) groups. The patient-focused intervention did not significantly affect the primary outcome measure between December, 2014, and March, 2015 (antibiotic items dispensed per 1000 population: 135·00 [95% CI 133·77–136·22] in the patient-focused intervention group and 133·98 [133·06–134·90] in the control group; IRR for difference between groups 1·01, 95% CI 1·00–1·02; p=0·105).

Interpretation

Social norm feedback from a high-profile messenger can substantially reduce antibiotic prescribing at low cost and at national scale; this outcome makes it a worthwhile addition to antimicrobial stewardship programmes.

Funding

Public Health England.

 

PDF

http://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(16)00215-4.pdf

April 22, 2016 at 8:01 am

Strong stewardship to fight antimicrobial resistance

Lancet April 23, 2016 V.387 N.10029

Editorial

Antibiotics have undoubtedly revolutionised medicine. However, widespread use of antimicrobial drugs in medicine and agriculture has spurred the evolution of pan-resistant bacterial strains. With few new antibiotics in the development pipeline, the threat to public health of antimicrobial resistance is all too real. Strong stewardship policies are urgently needed to stem inappropriate prescribing and use of antibiotics.

 

On April 13, the Infectious Diseases Society of America and the Society for Health Care Epidemiology of America released a new guideline: Implementing an Antibiotic Stewardship Program, with 27 recommendations that cover a broad range of antibiotic stewardship interventions. Among the recommendations are use of preauthorisation for antibiotic prescribing, restriction of use of antibiotics with high risk of Clostridium difficile infection, and strategies for specific health-care settings (such as nursing homes) to reduce unnecessary or inappropriate antibiotic use. Of note, although these recommendations can be used across a range of clinical settings, the authors highlight the lack evidence for effective antibiotic stewardship interventions, and call for increased research to determine how to best achieve large-scale implementation of these measures.

PDF

http://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(16)30302-6.pdf

April 22, 2016 at 8:00 am

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