Posts filed under ‘Resistencia bacteriana’

Descripción clínica y epidemiológica de un brote nosocomial por KPC en Buenos Aires, Argentina

Enf Inf & Microbiol Clínica 2012 V.30 N.7 P.376-79

Ezequiel Córdova a, María Inés Lespada a, Nora Gómez b, Fernando Pasterán c, Viviana Oviedo a y Claudia Rodríguez-Ismael a

a Grupo de Trabajo en Infectología, Hospital General de Agudos «Dr. Cosme Argerich», Buenos Aires, Argentina

b Laboratorio de Microbiología, Hospital General de Agudos «Dr. Cosme Argerich», Buenos Aires, Argentina c Servicio de Antimicrobianos, Departamento Bacteriología, Instituto Nacional de Enfermedades Infecciosas (INEI)-ANLIS «Dr. Carlos G. Malbrán», Buenos Aires, Argentina

Introducción

Klebsiella pneumoniae (K. pneumoniae) productora de carbapenemasa tipo KPC (Kpn-KPC) representa un patógeno emergente, con elevada capacidad de diseminación nosocomial. El objetivo del presente estudio es describir las características clinico epidemiológicas de un brote nosocomial por KpnKPC en Buenos Aires, Argentina.

Métodos

Estudio descriptivo y prospectivo. Se registraron los aspectos clinico epidemiológicos de pacientes con infección por Kpn-KPC (agosto de 2009 a julio de 2010). Se determinó la sensibilidad a los antimicrobianos mediante antibiograma por disco-difusión y por método automatizado (Vitek® 2 CbioMerieux). La búsqueda de carbapenemasa tipo KPC se realizó con la prueba de inhibición con 3-aminofenil-borónico (APB) y se confirmó su presencia por reacción en cadena de la polimerasa (PCR, por sus siglas en inglés). Se realizó tipificación molecular de las cepas aisladas por electroforesis en campo pulsado (PFGE, por sus siglas en inglés).

Resultados

Se registraron 27 casos de infección por Kpn-KPC (sala de cirugía general: n = 8; clínica médica: n = 6; unidad de cuidados intensivos: n = 5; sala de emergencia: n = 4; otras: n = 4). Todos los aislamientos de Kpn-KPC pertenecieron a un mismo clon (ST258). Los sitios de infección fueron: tracto urinario (63%), tracto respiratorio (15%), abdomen (15%), sangre (7%) y hueso (4%). Todos los aislamientos de KPn-KPC fueron solamente sensibles a tigeciclina y colistina. Tratamiento empírico inadecuado: 63%. Tratamiento efectivo dirigido: colistina (74%), tigeciclina (4%), tigeciclina + colistina (22%). Mortalidad global: 59% (atribuible: 26%). Cultivos de vigilancia (hisopados) positivos: 7/70 (10%).

Conclusiones

Se describe la emergencia de un brote nosocomial de Kpn-KPC en Buenos Aires, con alta capacidad de diseminación y elevada mortalidad. La implementación de medidas de control de infecciones es fundamental para reducir la transmisión nosocomial de Kpn-KPC

PDF

http://antimicrobianos.com.ar/ATB/wp-content/uploads/2012/11/Descripci%C3%B3n-cl%C3%ADnica-y-epidemiol%C3%B3gica-de-un-brote-nosocomial.pdf

 

July 25, 2015 at 3:58 pm

Evaluation of white cell count and differential in synovial fluid for diagnosing infections after total hip or knee arthroplasty.

PLoS One. 2014 Jan 8;9(1):e84751.

Qu X, Zhai Z, Liu X, Li H, Wu C, Li Y, Li H, Zhu Z, Qin A, Dai K.

Author information

Department of Orthopedics, Shanghai Key Laboratory of Orthopedic Implant, Shanghai Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.

Abstract

BACKGROUND:

The accuracy of synovial fluid (SF) white cell count (WCC) and polymorphonuclear (PMN) cell evaluation for predicting prosthetic joint infection (PJI) at the total hip arthroplasty (THA) or total knee arthroplasty (TKA) site is unknown. Therefore, we performed a meta-analysis to summarize the diagnostic validity of SF-WCC and SF-PMN for diagnosing PJI.

METHODS:

The MEDLINE, EMBASE, and OVID databases were searched for studies that had evaluated the diagnostic validity of SF-WCC and SF-PMN between January 1990 and May 2013. Meta-analysis methods were used to pool sensitivity, specificity, diagnostic odd ratios (DORs), the area under the receiver-operating characteristic curve (AUC), positive likelihood ratios (PLR), negative likelihood ratios (NLR), and post-test probability. We also conducted heterogeneity, publication bias, subgroup, and meta-regression analyses.

RESULTS:

Fifteen articles (15 SF-WCC and 14 SF-PMN) that included a total of 2787 patients fulfilled the inclusion criteria and were considered for analysis. The pooled sensitivity and specificity for PJI detection was 0.88 (95% confidence intervals [CI], 0.81-0.93) and 0.93 (95% CI, 0.88-0.96) for SF-WCC and 0.90 (95% CI, 0.84-0.93) and 0.88 (95% CI, 0.83-0.92) for SF-PMN, respectively. The AUC was 0.96 for SF-WCC and 0.95 for SF-PMN. PLR and NLR were 13.3 and 0.13 for SF-WCC, and 7.6 and 0.12 for SF-PMN, respectively. There was no evidence of publication bias. Low-clinical-scenario (pre-test probability, 20%) post-test probabilities were 3% for both negative SF-WCC and SF-PMN results. The subgroup analyses indicated that the sensitivity/specificity of THA were 0.73/0.96 for SF-WCC and 0.85/0.83 for SF-PMN, whereas those of TKA were 0.90/0.91 for SF-WCC and 0.90/0.88 for SF-PMN. We also found that collection of SF-WCC preoperatively had a higher sensitivity than that obtained intraoperatively (0.91 vs. 0.77).

CONCLUSIONS:

SF-WCC and SF-PMN have an adequate and clinically acceptable diagnostic value for detecting PJI, particularly after TKA.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3885622/pdf/pone.0084751.pdf

July 25, 2015 at 10:54 am

Efficacy of a novel PCR- and microarray-based method in diagnosis of a prosthetic joint infection.

Acta Orthop. 2014 Apr;85(2):165-70.

Metso L1, Mäki M, Tissari P, Remes V, Piiparinen P, Kirveskari J, Tarkka E, Anttila VJ, Vaara M, Huotari K.

Author information

1Department of Orthopedics , Peijas Hospital, Helsinki University Central Hospital.

Abstract

BACKGROUND AND PURPOSE:

Polymerase chain reaction (PCR) methods enable detection and species identification of many pathogens. We assessed the efficacy of a new PCR and microarray-based platform for detection of bacteria in prosthetic joint infections (PJIs).

METHODS:

This prospective study involved 61 suspected PJIs in hip and knee prostheses and 20 negative controls. 142 samples were analyzed by Prove-it Bone and Joint assay. The laboratory staff conducting the Prove-it analysis were not aware of the results of microbiological culture and clinical findings. The results of the analysis were compared with diagnosis of PJIs defined according to the Musculoskeletal Infection Society (MSIS) criteria and with the results of microbiological culture.

RESULTS:

38 of 61 suspected PJIs met the definition of PJI according to the MSIS criteria. Of the 38 patients, the PCR detected bacteria in 31 whereas bacterial culture was positive in 28 patients. 15 of the PJI patients were undergoing antimicrobial treatment as the samples for analysis were obtained. When antimicrobial treatment had lasted 4 days or more, PCR detected bacteria in 6 of the 9 patients, but positive cultures were noted in only 2 of the 9 patients. All PCR results for the controls were negative. Of the 61 suspected PJIs, there were false-positive PCR results in 6 cases.

INTERPRETATION:

The Prove-it assay was helpful in PJI diagnostics during ongoing antimicrobial treatment. Without preceding treatment with antimicrobials, PCR and microarray-based assay did not appear to give any additional information over culture.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3967259/pdf/ORT-85-165.pdf

July 25, 2015 at 10:52 am

Sensitivities, specificities, and predictive values of microbiological culture techniques for the diagnosis of prosthetic joint infection.

Biomed Res Int. 2014;2014:180416.

Jordan RW1, Smith NA2, Saithna A1, Sprowson AP2, Foguet P1.

Author information

1University Hospital Coventry & Warwickshire, Clifford Bridge Road, Coventry CV2 2DX, UK.

2University of Warwick, Coventry CV4 7AL, UK.

Abstract

BACKGROUND:

Identifying the microorganism in a prosthetic joint infection is the key to appropriately targeting antimicrobial treatment. Despite the availability of various techniques, no single test is considered the definitive gold standard.

AIM:

Our aim was to determine the sensitivity, specificity, and positive/negative predictive values for a variety of culture techniques.

METHODS:

We performed a retrospective case series of 219 patients undergoing revision surgery of their hip or knee replacement between May 2004 and February 2013. The patients were classified as either infected or noninfected according to criteria set out by the Musculoskeletal Infection Society. The number and type of samples taken intraoperatively varied between cases but included tissue samples and fluid sent in either blood culture vials or sterile containers.

RESULTS:

The highest sensitivity was found with blood culture vials (0.85) compared to fluid in sterile containers (0.26) and tissues samples (0.32). Blood culture vials also had a better specificity and positive and negative predictive values profile.

CONCLUSION:

We conclude that, of the techniques studied, fluid in blood culture vials had the best profile for the correct identification of microorganisms and advocate its use.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4055545/pdf/BMRI2014-180416.pdf

July 25, 2015 at 10:50 am

Emergence of Klebsiella pneumoniae Carbapenemase (KPC)-Producing Bacteria

South Med J. 2011 Jan; 104(1): 40–45.

Ryan S. Arnold, MD,1 Kerri A. Thom, MD, MS,2 Saarika Sharma, MD MA,4 Michael Phillips, MD,4 J. Kristie Johnson, PhD,3 and Daniel J. Morgan, MD2,5

1Department of Medicine, University of Maryland, Baltimore

2Department of Epidemiology and Public Health, University of Maryland, Baltimore

3Department of Pathology, University of Maryland, Baltimore

4Division of Infectious Disease, NYU School of Medicine, New York

5VA Maryland Health Care System

Klebsiella pneumoniae carbapenemase (KPC)-producing bacteria are a group of emerging highly drug-resistant Gram-negative bacilli causing infections associated with significant morbidity and mortality.

Once confined to outbreaks in the northeastern United States (US), they have spread throughout the US and most of the world. KPCs are an important mechanism of resistance for an increasingly wide range of Gram-negative bacteria and are no longer limited to K pneumoniae.

KPC-producing bacteria are often misidentified by routine microbiological susceptibility testing and incorrectly reported as sensitive to carbapenems; however, resistance to the carbapenem antibiotic ertapenem is common and a better indicator of the presence of KPCs.

Carbapenem antibiotics are generally not effective against KPC-producing organisms. The best therapeutic approach to KPC-producing organisms has yet to be defined; however, common treatments based on in vitro susceptibility testing are the polymyxins, tigecycline, and less frequently aminoglycoside antibiotics.

The purpose of this review is to identify the various challenges that KPC-producing bacteria present to clinicians. These include the need for special techniques for microbiological detection, the potential for nosocomial transmission, and therapeutic challenges related to limited, relatively unproven antimicrobial treatment options.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3075864/pdf/nihms-253051.pdf

July 23, 2015 at 11:03 am

Reviving old antibiotics

Journal of Antimicrobial Chemotherapy August 2015 V.70 N.8 P.2177-2181

Editor’s Choice

Ursula Theuretzbacher, Françoise Van Bambeke, Rafael Cantón, Christian G. Giske, Johan W. Mouton, Roger L. Nation, Mical Paul, John D. Turnidge, and Gunnar Kahlmeter

1Center for Anti-Infective Agents, Vienna, Austria

2Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium

3Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Biomédica (IRYCIS), Madrid, Spain

4Clinical Microbiology, L2:02, Karolinska University Hospital, Solna, Stockholm, Sweden

5Department of Laboratory Medicine (LABMED), Division of Clinical Microbiology, Karolinska Institutet, Huddinge, Sweden

6Department of Medical Microbiology and Infectious Diseases Erasmus MC, Rotterdam, The Netherlands

7Department of Medical Microbiology, Radboudumc Radboud University, Nijmegen, The Netherlands

8Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia

9Division of Infectious Diseases, Rambam Health Care Campus and Faculty of Medicine, Technion – Israel Institute of Technology, Haifa, Israel

10School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia

11Department of Clinical Microbiology, Central Hospital, Växjö, Sweden

12Department of Medical Sciences, Division of Clinical Bacteriology, Uppsala University, Uppsala, Sweden

*Corresponding author. Center for Anti-Infective Agents, Eckpergasse 13, 1180 Vienna, Austria. Tel: +43-14797024; E-mail: utheuretzbacher@cefaia.com

In the face of increasing antimicrobial resistance and the paucity of new antimicrobial agents it has become clear that new antimicrobial strategies are urgently needed.

One of these is to revisit old antibiotics to ensure that they are used correctly and to their full potential, as well as to determine whether one or several of them can help alleviate the pressure on more recent agents.

Strategies are urgently needed to ‘re-develop’ these drugs using modern standards, integrating new knowledge into regulatory frameworks and communicating the knowledge from the research bench to the bedside.

Without a systematic approach to re-developing these old drugs and rigorously testing them according to today’s standards, there is a significant risk of doing harm to patients and further increasing multidrug resistance.

This paper describes factors to be considered and outlines steps and actions needed to re-develop old antibiotics so that they can be used effectively for the treatment of infections.

PDF

http://jac.oxfordjournals.org/content/70/8/2177.full.pdf+html

July 15, 2015 at 8:33 am

Within-host diversity of MRSA antimicrobial resistances

Journal of Antimicrobial Chemotherapy August 2015 V.70 N.8 P.2191-2198

Kinga I. Stanczak-Mrozek, Anusha Manne, Gwenan M. Knight, Katherine Gould, Adam A. Witney, and Jodi A. Lindsay

1Institute for Infection and Immunity, St George’s, University of London, Cranmer Terrace, London SW17 0RE, UK

2Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK

*Corresponding author. Tel: +44-(0)208-725-0445; E-mail: jlindsay@sgul.ac.uk

Objectives

MRSA is a major antimicrobial resistance (AMR) pathogen. The reservoir of infecting isolates is colonization, which is the site of evolutionary selection. The aim was to identify if AMRs in colonizing MRSA populations diversified and potential mechanisms of resistance gene transfer in vivo.

Methods

Nasal swabs from 38 MRSA carriers admitted to hospital were plated and 20 individual colonies from each patient tested for phenotypic antibiotic susceptibility and genetically for lineage, carriage of four prophages and three plasmid families. Free bacteriophages were detected in swabs as well as their capacity for transducing resistance genes.

Results

Nine (24%) patients carried phenotypic AMR variants and 24 (63%) carried prophage and plasmid variants. If a single colony was selected for testing, the probability of detecting all AMR in that patient was 87%. Sixty-four different AMR and mobile genetic element (MGE) profiles were detected, mostly in the MRSA CC22 background (where CC stands for clonal complex), with up to 8 profiles per patient. Nearly half of the patients carried detectable free bacteriophages and phages successfully transduced resistance genes between laboratory and patient isolates in vitro. WGS showed MRSA core genomes were stable, while AMR and MGEs varied.

Conclusions

‘Clouds’ of MRSA variants that have acquired or lost AMR and MGEs are common in nasal colonizing populations and bacteriophages may play an important role in gene transfer. Accurate estimation of AMR and genetic variability has implications for diagnostics, epidemiology, antimicrobial stewardship and understanding the evolutionary selection of AMR in colonizing populations.

PDF

http://jac.oxfordjournals.org/content/70/8/2191.full.pdf+html

 

July 15, 2015 at 8:31 am

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