Evaluación de la herramienta SaTScan-Whonet para la detección precoz de brotes en infecciones bacterianas en una institución de tercer nivel de atención en Colombia / Evaluation of the SaTScan-Whonet tool for detecting outbreaks of bacterial infection in a tertiary healthcare institution in Colombia

Introducción: Las infecciones asociadas al cuidado de la salud representan un problema de salud pública y la transmisión horizontal supone un incremento en la morbimortalidad y los costos en la atención. La vigilancia activa es costosa y tiene alto riesgo de omitir la detección de brotes, mientras que la virtual (modelos matemáticos) permite la búsqueda sistemática de alertas de brotes. El objetivo de este estudio es evaluar la relación costo-efectividad del uso de la herramienta SaTScan-Whonet para la detección temprana de infecciones bacterianas, comparada con la vigilancia tradicional en una institución de alta complejidad de Colombia. Metodología: En un hospital universitario de alta complejidad se realizó un estudio retrospectivo, se identificó un brote bacteriano, se caracterizó clínicamente y por biología molecular. Se extrajeron las bases de datos de los sistemas automatizados de identificación y susceptibilidad microbiológica. Se realizaron análisis retrospectivos de SaTScan-Whonet, así como simulaciones diarias para el primer semestre de 2011 de manera prospectiva; también se identificó la fecha para la alerta de detección de brote, tanto en la vigilancia activa como en la virtual. Resultados: Se aislaron 4.584 microorganismos en los servicios de hospitalización tanto UCI como no UCI entre 2010 y 2011 (2.288 y 2.296 respectivamente). Por vigilancia activa se notificó un brote por Enterococcus faecium el 28 de marzo de 2011, que fue caracterizado por biología molecular con la presencia del gen Van A, que confiere resistencia a glucopéptidos. Se identificó de manera retrospectiva una alerta de brote para E. faecium entre el 14 de marzo y el 10 de mayo de 2011 con un intervalo de recurrencia de 609.384. En los análisis prospectivos simulados se identificó la primera alerta de brote de esta bacteria el 13 de abril de 2011 con un intervalo de recurrencia de 3.897 (p = 0,0002655). Conclusión: La utilización de dicha herramienta de manera prospectiva no fue superior a la vigilancia activa en cuanto a oportunidad en la detección. Los análisis retrospectivos tuvieron un alto rendimiento diagnóstico y podrían ser de utilidad para los sistemas de vigilancia y control de los entes reguladores.

Background: Healthcare-associated infections represent a public health problem, and horizontal transmission has led to an increase in morbidity and mortality as well as higher health care costs. Active surveillance is expensive and carries high risk of failing to detect outbreaks. Virtual surveillance (mathematical models) allows a systematic search for alerts to outbreaks. The objective of this study is to evaluate the cost-effectiveness of the SaTScan-Whonet tool for the early detection of outbreaks of bacterial infection, compared with traditional surveillance, in an institution of high complexity in Colombia. Methodology: In a university hospital of high complexity a retrospective study was performed, identifying a bacterial outbreak that was characterised clinically and by molecular biology techniques. Databases of automated systems of identification and microbiological susceptibility were extracted. Retrospective analyses were performed using SaTScan-Whonet and daily simulations during the first semester of 2011 in a prospective manner. The date for the alert to the detection of the outbreak for both active and virtual surveillance was also identified. Results: A total of 4,584 microorganisms were isolated both inside and outside the ICU bet-ween 2010 and 2011 (2,288 and 2,296, respectively). An outbreak of Enterococcus faecium was identified by active surveillance on March 28, 2011. Using molecular biology techniques, the outbreak was characterised, showing the presence of the vanA gene, which confers resistance to glycopeptides. An alert to an Enterococcus faecium outbreak was retrospectively identified between March 14 and May 10, 2011 with a recurrence interval of 609,384. The first alert to outbreak for this bacterium was identified in a prospective simulated analysis on April 13, 2011 with a recurrence interval of 3,897 (P=.0002655). Conclusion: The use of such a tool prospectively is not superior to active surveillance in regard to timely detection of bacterial outbreaks. Retrospective analyses have high diagnostic ability and could be very helpful in systems of surveillance and control of regulatory entities.

Susceptibility rates in Latin American nations: report from a regional resistance surveillance program (2011)

OBJECTIVE: To establish a resistance (R) surveillance program monitoring antimicrobial susceptibility patterns in Latin America (LATAM; Argentina [ARG], Brazil [BRA], Chile, Colombia [CBA], Costa Rica, Ecuador [ECU], Guatemala [GUA], Mexico [MEX], Panama [PAN], Peru, and Venezuela [VEN]). METHODS: In 2011, 4979 organisms were collected from 11 nations (20 laboratories) for susceptibility testing in a central laboratory design. Antimicrobials were tested by CLSI methods and results interpreted by CLSI and EUCAST breakpoints. Most common Gram-positive (Staphylococcus aureus [SA, 921], other staphylococci [CoNS; 299], enterococci [218], Streptococcus pneumoniae [SPN; 182], β-haemolytic streptococci [115]) and Gram-negative (E. coli [EC; 644], Klebsiella spp. [KSP; 517], Enterobacters [272], Pseudomonas aeruginosa [PSA; 586], Acinetobacters [ACB; 494]) pathogens were analyzed against linezolid (LZD), vancomycin (VAN), tigecycline (TIG), colistin (COL), cefoperazone/sulbactam (C/S), and amikacin (AMK). RESULTS: MRSA rates varied from 29% (CBA, BRA) to 79% (Peru); but LZD (MIC90, 2 mg/L), TIG (MIC90, 0.12mg/L) and VAN (MIC90, 1mg/L) covered all strains. Enterococci showed a 14% VRE rate, highest in BRA and MEX; all inhibited by TIG and daptomycin, but not LZD (three non-susceptible with G2576T mutations or cfr). Penicillin-R among SPN and viridans streptococci was 51.6 and 41.1%, respectively. LZD overall R against Gram-positives was 0.3%. High ESBL rates were observed in EC (54-71%) and KSP (>50%) from GUA, MEX and Peru, and six nations, respectively. Carbapenem-R in KSP was 9%, highest rates associated with KPC in BRA, CBA, ECU, PAN and VEN; also a NDM-1 in KSP from CBA. AMK, TIG, C/S and carbapenems were the broadest-spectrum agents tested against Enterobacteriaceae. Only COL inhibited >90% of PSA; COL and TIG (<2 mg/L) covered >85% of ACB. CONCLUSIONS: LATAM nations demonstrated variable levels of antimicrobial R especially among Enterobacteriaceae (β-lactamase-mediated), PSA and ACB. MRSA (48%), VRE (14%) and multidrug-R SPN were also regional therapeutic challenges.