Control of a Clonal Outbreak of Multidrug-Resistant Acinetobacter baumannii in a Hospital of the Basque Country after the Introduction of Environmental Cleaning Led by the Systematic Sampling from Environmental Objects.

Background. Between July 2009 and September 2010, an outbreak of multidrug-resistant (MDR) Acinetobacter baumannii was detected in one critical care unit of a tertiary hospital in the Basque Country, involving 49 infected and 16 colonized patients. The aim was to evaluate the impact of environmental cleaning and systematic sampling from environmental objects on the risk of infection by MDR A. baumannii. Methods. After systematic sampling from environmental objects and molecular typing of all new MDR A. baumannii strains from patients and environmental isolates, we analyzed the correlation (Pearson's r) between new infected cases and positive environmental samples. The risk ratio (RR) of infection was estimated with Poisson regression. Results. The risk increased significantly with the number of positive samples in common areas (RR = 1.40; 95%CI = 0.99-1.94) and positive samples in boxes (RR = 1.19; 95%CI = 1.01-1.40). The number of cases also positively correlated with positive samples in boxes (r = 0.50; P < 0.05) and common areas (r = 0.29; P = 0.18). Conclusion. Once conventional measures have failed, environmental cleaning, guided by systematic sampling from environmental objects, provided the objective risk reduction of new cases and enabled the full control of the outbreak.

Estudio comparativo de QuantiFERON ®-TB Gold IT frente a tuberculina para el diagnóstico de la infección tuberculosa latente en estudios de contactos / Comparative performance of QuantiFERON ®-TB Gold IT versus Tuberculin Skin Test among contact investigations for latent tuberculosis infection

Fundamento y objetivo: Hasta hace poco, la única técnica disponible para diagnosticar la infección tuberculosa latente (ITL) era la tuberculina (PPD). QuantiFERON®-TB Gold In-Tube (QF), al igual que otros métodos diagnósticos basados en la liberación de interferón-γ (IGRA), aparecen como una alternativa a la PPD. El objetivo del estudio es comparar ambas técnicas (PPD y QF) para evaluar la utilidad diagnóstica y factibilidad del uso rutinario de QF en estudios de contactos. Pacientes y método: Estudio descriptivo prospectivo de concordancia entre PPD y QF a partir de contactos de pacientes con tuberculosis confirmada mediante cultivo entre mayo de 2007 y febrero de 2008 en Bizkaia y Araba, estimándose la concordancia mediante el estadístico kappa (κ).Resultados: Se hallaron 376 contactos: 8 niños (edad ≤ 14 años) de alto riesgo, 30 niños de riesgo bajo-medio, 46 adultos (edad > 14 años) de alto riesgo y 270 adultos de riesgo bajo-medio. Un total de 160 contactos (42,5%) fueron PPD+ para PPD ≥ 5mm, 141 (37,5%) para PPD ≥ 10mm y 95 (25,3%) para PPD ≥ 15mm. Mediante QF se obtuvieron 94 positivos, 279 negativos y tres indeterminados. Aunque en conjunto hay buena concordancia para PPD ≥ 10mm (κ=0,53; p < 0,0001), hubo pobre concordancia cuando el caso índice era no bacilífero para PPD ≥ 5mm (κ=0,28; p<0,001) y en contactos de alto riesgo para PPD ≥ 15mm (κ=0,048; p=0,36). Conclusiones: Frente a PPD, los IGRA constituyen una excelente herramienta en Salud Pública para el diagnóstico de la ITL, proporcionando un diagnóstico más específico, reduciendo el número potencial de tratamientos y mejorando el aprovechamiento de recursos sanitarios (AU)

Background and objective: Until recently, the only tool for detection of latent tuberculosis infection (LTI) was the tuberculin skin test (PPD). QuantiFERON®-TB Gold In-Tube (QF), as well as other Mycobacterium tuberculosis-specific interferon-γ release assays (IGRAs), appears to be an alternative or adjunct to the PPD. The goal of the study was to compare QF with PPD to evaluate de accuracy of QF for routinely identifying LTI in contact investigations. Patients and method:We performed a descriptive and prospective study with contacts of culture-confirmed tuberculosis source cases in Bizkaia and Araba from May 2007 through February 2008 who underwent QF and PPD. Concordance between both tests was analyzed using the kappa statistic (κ). Results: 376 contacts were found: 8 were high-risk children (age < 15), 30 low-medium risk children, 46 high-risk adults (age>14) and 270 low-medium risk adults. PPD was positive in 160 subjects (42.5%) at PPD ≥ 5mm, 141 (37.5%) at PPD ≥ 10mm and 95 (25.3%) at PPD ≥ 15mm. In QF analysis 94 subjects were positive, 279 negative and 3 indeterminate. Overall agreement between QF and PPD was good at PPD ≥ 10mm (κ=0.53; p<0.0001) but agreement was poor when the index case had positive baciloscopy at PPD ≥ 5mm (κ=0.28; p<0.001) and high-risk contacts at PPD ≥ 15mm (κ=0.048; p=0.36). Conclusions: IGRAs are an accurate indicator of LTI, providing a more specific way of diagnostic and reducing the number of subjects to be treated. QF appears to be a valuable public health tool with potential advantages over the PPD and improving resources (AU)

[Comparative performance of QuantiFERON(®)-TB Gold IT versus tuberculin skin test among contact investigations for latent tuberculosis infection]. / Estudio comparativo de QuantiFERON(®)-TB Gold IT frente a tuberculina para el diagnóstico de la infección tuberculosa latente en estudios de contactos.

BACKGROUND AND OBJECTIVE: Until recently, the only tool for detection of latent tuberculosis infection (LTI) was the tuberculin skin test (PPD). QuantiFERON(®)-TB Gold In-Tube (QF), as well as other Mycobacterium tuberculosis-specific interferon-γ release assays (IGRAs), appears to be an alternative or adjunct to the PPD. The goal of the study was to compare QF with PPD to evaluate de accuracy of QF for routinely identifying LTI in contact investigations. PATIENTS AND METHOD: We performed a descriptive and prospective study with contacts of culture-confirmed tuberculosis source cases in Bizkaia and Araba from May 2007 through February 2008 who underwent QF and PPD. Concordance between both tests was analyzed using the kappa statistic (κ). RESULTS: 376 contacts were found: 8 were high-risk children (age < 15), 30 low-medium risk children, 46 high-risk adults (age>14) and 270 low-medium risk adults. PPD was positive in 160 subjects (42.5%) at PPD ≥ 5mm, 141 (37.5%) at PPD ≥ 10mm and 95 (25.3%) at PPD ≥ 15 mm. In QF analysis 94 subjects were positive, 279 negative and 3 indeterminate. Overall agreement between QF and PPD was good at PPD ≥ 10mm (κ=0.53; p<0.0001) but agreement was poor when the index case had positive baciloscopy at PPD ≥ 5mm (κ=0.28; p<0.001) and high-risk contacts at PPD ≥ 15 mm (κ=0.048; p=0.36). CONCLUSIONS: IGRAs are an accurate indicator of LTI, providing a more specific way of diagnostic and reducing the number of subjects to be treated. QF appears to be a valuable public health tool with potential advantages over the PPD and improving resources.