Juan Sebastián Castillo

Frequency of microorganisms isolated in patients with bacteremia in intensive care units in Colombia and their resistance profiles

OBJECTIVE The aim of this study was to describe the most frequently found bacterial microorganisms in bloodstream isolates taken from patients in intensive care units in Colombia and their resistance profiles. METHODS This was a multicentre descriptive observational study that was carried out between January 2001 and June 2008 with laboratory data from 33 participating hospitals in a surveillance network. RESULTS The most frequently found microorganisms were coagulase-negative Staphylococci 39.6%, Staphylococcus aureus 12.3%, Klebsiella pneumoniae 8.2%, Escherichia coli 5.7%, Acinetobacter baumannii, 4.0% and Pseudomonas aeruginosa 3.8%. Coagulase-negative Staphylococci registered greater than 70% oxacillin resistance rate. S. aureus presented a change in its multiresistance profile during the years of follow-up. There was a trend towards a lower resistance rate among E. coli and K. pneumoniae isolates during the study period while A. baumannii carbapenem resistance rate exceeded 50%. DISCUSSION There has been a change in the frequency of species being isolated with a higher frequency of enterobacteriaceae compared to Gram-positive microorganisms, in general with a high resistance rate.

Mortality among critically ill patients with methicillin-resistant Staphylococcus aureus bacteremia: a multicenter cohort study in Colombia

OBJECTIVE To evaluate risk factors associated with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia emergence, its prognosis, and mortality-determining factors in critically ill patients in Colombia. METHODS A multicenter, retrospective cohort study conducted in 2005-2008 at 16 public and private reference health care institutions in Bogotá, Colombia, that form part of a national epidemiological surveillance network and a hospital network with 4 469 beds. Methicillin-resistant emergence and mortality were analyzed using descriptive and time-to-event analysis; a multivariate Cox proportional hazard regression model was built to test the association between methicillin resistance and mortality. RESULTS A total of 372 patients were studied: 186 with MRSA bacteremia, randomly matched with 186 with methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. Previous surgery, antibiotic exposure, and hospital-acquired infections were independently associated with methicillin resistance. MRSA caused longer hospital stays among survivors (median 24 versus 18 days, P = 0.014). Mortality predictors were: patient age, creatinine level over 1.21 mg/dl at ICU admission, severe sepsis, and inotropic requirement. Appropriate antimicrobial therapy and antimicrobial therapy change were independent protective factors, as was male gender. CONCLUSIONS Methicillin resistance per se was not a mortality-independent prognostic factor. Previous conditions, such as age, baseline renal impairment, severe sepsis, and inotropy demand explained the observed mortality. Appropriate antimicrobial therapy remained a protective factor. A call to improve infection control measures in Colombia is mandatory.

Métodos diagnósticos en candidemia: una revisión sistemática de la literatura con meta-análisis

Candidemia is a disease with high morbidity and mortality especially in critical care patients. Early diagnosis enables early treatment. Objectives: To conduct a systematic review of the literature in order to establish the best laboratory tests for the diagnosis of candidemia in critical patients. Materials and Methods: We conducted a systematic review of available literature in PubMed. Serological studies were subjected to meta-analysis in metadisk-Beta 1.1.1. Results: 4 studies of 1286 reviewed were included. Three were about serological tests and one about molecular testing (RT-PCR). The sensitivity and specifi city for RT-PCR, antibody testing and antigen and antibody tests were 87% and 100%, 47.5% and 82.6%, 96% and 81%, respectively. Diagnostic Odds Ratio of antigenemia was 1.51 (95% CI = 0,032-70,964, p = 0.001). Conclusions: RT-PCR has better diagnostic performance, measuring antigenemia plus antibodies improves sensitivity, specifi city, LR + and LR-¬. There is insuffi cient evidence to support this.

Intervenciones de consejería para la cesación de la adicción al tabaco: revisión sistemática de la literatura

Objective. A systematic review on efficacy and safety of smoking cessation counseling was developed. Materials and methods. The ADAPTE methodology was used with a search of Clinical Practice Guidelines (CPG) in Medline, EMBASE, CINAHL, LILACS, and Cochrane. DELBI was used to select CPG with score over 60 in methodological rigor and applicability to the Colombian health system. Smoking cessation rates at 6 months were assessed according to counseling provider, model, and format. In total 5 CPG out of 925 references were selected comprising 44 systematic reviews and metaanalyses. Results. Physician brief counseling and trained health professionals’ intensive counseling (individual, group, proactive telephone) are effective with abstinence rates between 2.1% and 17.4%. Only practical counseling and motivational interview were found effective intensive interventions. The clinical effect of smoking cessation counseling is low and long term cessation rates uncertain. Conclusion. Cost-effectiveness analyses are recommended for the implementation of counseling in public health programs.

Prioritization strategies in clinical practice guidelines development: a pilot study

ObjectiveFew methodological studies address the prioritization of clinical topics for the development of Clinical Practice Guidelines (CPGs). The aim of this study was to validate a methodology for Priority Determination of Topics (PDT) of CPGs.Methods and resultsFirstly, we developed an instrument for PDT with 41 criteria that were grouped under 10 domains, based on a comprehensive systematic search. Secondly, we performed a survey of stakeholders involved in CPGs development, and end users of guidelines, using the instrument. Thirdly, a pilot testing of the PDT procedure was performed in order to choose 10 guideline topics among 34 proposed projects; using a multi-criteria analysis approach, we validated a mechanism that followed five stages: determination of the composition of groups, item/domain scoring, weights determination, quality of the information used to support judgments, and finally, topic selection. Participants first scored the importance of each domain, after which four different weighting procedures were calculated (including the survey results). The process of weighting was determined by correlating the data between them. We also reported the quality of evidence used for PDT. Finally, we provided a qualitative analysis of the process. The main domains used to support judgement, having higher quality scores and weightings, were feasibility, disease burden, implementation and information needs. Other important domains such as user preferences, adverse events, potential for health promotion, social effects, and economic impact had lower relevance for clinicians. Criteria for prioritization were mainly judged through professional experience, while good quality information was only used in 15% of cases.ConclusionThe main advantages of the proposed methodology are supported by the use of a systematic approach to identify, score and weight guideline topics selection, limiting or exposing the influence of personal biases. However, the methodology was complex and included a number of quantitative and qualitative approaches reflecting the difficulties of the prioritization process.

Systematic review of antimicrobial resistance among Gram positive cocci in hospitals in Colombia

INTRODUCTION Bacterial resistance is a public health problem worldwide whose proper management requires knowledge of its presence and its behavior in each region and country. OBJECTIVES A survey of the medical literature was conducted to identify levels of resistance to antibiotic markers in Gram positive bacterial isolates from Colombian hospitals. MATERIALS AND METHODS A systematic review of the literature included articles indexed in MEDLINE and LILACS. A manual search was made of Colombian scientific journals and other infectious disease literature not available electronically. RESULTS A total of 34 observational studies were located, including a series of consecutive reports initiated in 2001. Most of the reports came from the city of Bogota. The rate of methicillin resistance for Staphylococcus aureus and coagulase-negative staphylococci in non intensive care unit isolates ranged between 35%-50% and 72%-76%, respectively. Resistance in intensive care unit isolates had a range between 35%-71% and 74%-83%, respectively. The rate of vancomycin-resistant Enterococcus faecium averaged less than 20% over the years but with large annual variation . CONCLUSIONS Resistance markers appeared in high frequency among Gram positive isolates identified in hospitals in major Colombian cities.

Risk factors for methicillin-resistant Staphylococcus aureus bacteremia: A multicenter matched case-control study

INTRODUCTION Methicillin-resistant Staphylococcus aureus is a frequent pathogen at critical care services. Its presence leads to increased hospital stays and mortality risk in patients with bacteremia. However, the etiology of this resistance marker has not been fully studied. OBJECTIVE To identify risk factors associated with the emergence of methicillin-resistant S. aureus bacteremia in critically ill patients treated at intensive care units in Bogotá, Colombia. MATERIALS AND METHODS We conducted a retrospective paired case-control study, nested in a cohort of patients diagnosed with S. aureus bacteremia and treated at intensive care units between 2006 and 2008 in Bogotá. Cases were patients with positive blood culture to methicillin resistance, matched in a 1:1 ratio with methicillin-sensitive controls isolated from the same institution and hospitalization year. We used conditional logistic regression to analyze the risk factors associated with the presence of resistance, with emphasis on prior antibiotic therapy. RESULTS We included 372 patients with S. aureus bacteremia. Factors such as the use of pre-hospital devices: vascular (OR=1.986, 95% CI 1.038 to 3.801) and urinary (OR=2.559, 95% CI: 1.170 to 5.596), along with the number of previously used antibiotics, were associated with the emergence of resistance. The number of antibiotics used previously was determined to have a gradient effect, particularly carbapenems. CONCLUSIONS The rational use of antibiotics and surveillance of exposure to surgical procedures or use of invasive devices are interventions that could diminish the emergence of methicillin-resistant S. aureus bacteremia causes.

Bacteriemia por Staphylococcus aureus resistente a la meticilina en la unidad de cuidados intensivos:revisión de los estudios de pronóstico

Staphylococcus aureus es una de los principales causas de infeccion de pacientes en estado critico. La informacion de vigilancia muestra 32,9 % de resistencia a la meticilina y una frecuencia de aislamiento como causante de infeccion de 12,15 % en las unidades de cuidados intensivos, especialmente infecciones del torrente sanguineo. No se encontraron articulos de sintesis de de los datos sobre el impacto de la resistencia de esta bacteria en la mortalidad de los pacientes gravemente comprometidos. Esta revision de la literatura resume los estudios de pronostico sobre la infeccion del torrente sanguineo por S. aureus resistente a meticilina (SARM) en pacientes de la unidad de cuidados intensivos. Se incluyeron los articulos que evaluaron la mortalidad por bacteriemias primarias o secundarias, comparandola con controles sensibles a la meticilina o infectados por otra bacteria. No se incluyeron estudios con bacteriemias polimicrobianas. De 387 referencias, seis estudios cumplieron los criterios de inclusion. Los datos disponibles no permiten generar una conclusion sobre la mortalidad relacionada con SARM en la unidad de cuidados intensivos. Los analisis bivariados muestran un incremento de la mortalidad, el cual tiende a desaparecer cuando se controla por otras variables, como el tratamiento inicial apropiado y la gravedad del cuadro clinico. La participacion de este microorganismo en la mortalidad de pacientes de la unidad de cuidados intensivos y sus determinantes, permanecen aun sin explicar.