Evaluation of a new rapid diagnostic test for the detection of influenza and RSV / Evaluación de un nuevo test de diagnóstico rápido para la detección de influenza y VRS

INTRODUCTION: Influenza viruses and respiratory syncytial virus (RSV) can cause an acute respiratory disease that occurs seasonally in epidemic waves. This retrospective study was conducted to evaluate the Sofia®Influenza A + B and the Sofia® RSV fluorescence immunoassays (FIAs), two novel rapid detection tests (RDTs) for influenza A and B and RSV. METHODS: Two hundred and nine breath samples were selected from patients with respiratory symptoms determined to be positive/negative for influenza A, influenza B or RSV using one of the reference diagnostic techniques, cell culture and/or RT-PCR (Simplexa™Flu A/B & RSV). The Sofia Influenza A + B FIA was tested on 123 samples (63 from children and 60 from adults) and the Sofia RSV FIA was tested on 86 pediatric samples. Sensitivity and specificity values of both assays were calculated assuming the reference techniques as the gold standard. RESULTS: Sensitivity and specificity values for the Sofia Influenza A + B FIA were 73.1% and 97.8%, respectively. Sensitivity and specificity values for the Sofia RSV FIA were 87.5% and 86.7%, respectively. CONCLUSION: The sensitivity results obtained for the two assays were considerably higher than those reported for other RDTs. In conclusion, the Sofia Influenza A + B and the Sofia RSV FIAs are appropriate tools for the rapid diagnosis of these viruses

INTRODUCCIÓN: Los virus influenza A y B y el virus respiratorio sincitial (VRS) causan infecciones respiratorias agudas de forma estacional en olas epidémicas. Este estudio restrospectivo se llevó a cabo para evaluar dos nuevos tests de diagnóstico rápido para detectar los virus influenza A y B y VRS: Sofia® Influenza A + B y Sofia® RSV Fluorescence Immunoassays (FIAs). MÉTODOS: Se seleccionaron 209 muestras respiratorias procedentes de pacientes con síntomas respiratorios en las que se había establecido el diagnóstico de presencia o ausencia de influenza A, influenza B o VRS mediante las técnicas de referencia: cultivo celular o RT-PCR PCR (Simplexa™Flu A/B & RSV). Sofia Influenza A + B se realizó en 123 muestras (63 de niños y 60 de adultos) y Sofia RSV en 86 muestras pediátricas. Se calcularon los valores de sensibilidad y especificidad de ambos test tomando las técnicas de referencia como gold standard. RESULTADOS: Los valores de sensibilidad y especificidad de Sofia Influenza A + B fueron 73,1 y 97,8%. Los valores de sensibilidad y especificidad de Sofia RSV fueron 87,5 y 86,7%. CONCLUSIONES: Los valores de sensibilidad obtenidos para ambos tests son mayores que los descritos para otras técnicas de diagnóstico rápido. Por lo tanto, Sofia Influenza A + B FIA y Sofia RSV FIA son test adecuados para el diagnóstico rápido de influenza y VRS

Evaluation of a new rapid diagnostic test for the detection of influenza and RSV.

INTRODUCTION: Influenza viruses and respiratory syncytial virus (RSV) can cause an acute respiratory disease that occurs seasonally in epidemic waves. This retrospective study was conducted to evaluate the Sofia(®) Influenza A+B and the Sofia(®) RSV fluorescence immunoassays (FIAs), two novel rapid detection tests (RDTs) for influenza A and B and RSV. METHODS: Two hundred and nine breath samples were selected from patients with respiratory symptoms determined to be positive/negative for influenza A, influenza B or RSV using one of the reference diagnostic techniques, cell culture and/or RT-PCR (Simplexa™Flu A/B & RSV). The Sofia Influenza A+B FIA was tested on 123 samples (63 from children and 60 from adults) and the Sofia RSV FIA was tested on 86 pediatric samples. Sensitivity and specificity values of both assays were calculated assuming the reference techniques as the gold standard. RESULTS: Sensitivity and specificity values for the Sofia Influenza A+B FIA were 73.1% and 97.8%, respectively. Sensitivity and specificity values for the Sofia RSV FIA were 87.5% and 86.7%, respectively. CONCLUSION: The sensitivity results obtained for the two assays were considerably higher than those reported for other RDTs. In conclusion, the Sofia Influenza A+B and the Sofia RSV FIAs are appropriate tools for the rapid diagnosis of these viruses.

Multiclonal spread of VIM-1-producing Enterobacter cloacae isolates associated with In624 and In488 integrons located in an IncHI2 plasmid.

Over a 6-year period (2007-2012), the emergence of Enterobacter cloacae isolates resistant to ß-lactams and with reduced susceptibility to carbapenems was observed in Hospital Universitario 12 de Octubre (Madrid, Spain). To determine the possible role of metallo-ß-lactamases (MBLs) in the resistance profile of these isolates, a molecular and clinical epidemiological study was performed, including determination of patients' clinical characteristics, genetic diversity of strains, resistance mechanisms to carbapenems, and the genetic environment of VIM-1. A total of 73 E. cloacae isolates showed resistance to extended-spectrum cephalosporins and reduced susceptibility to at least one carbapenem during 2007-2012. PCR amplification revealed the presence of bla(VIM-1) gene in 37 isolates, bla(VIM-2) in 1 isolate and bla(KPC) in 5 isolates. Molecular typing showed high clonal diversity of E. cloacae isolates carrying bla(VIM-1). The genetic environment of bla(VIM-1) was investigated and two integron structures were found: intI-bla(VIM-1)-aacA4-dfrB1-aadA1-catB2-qacEΔ1/sul1 (In624); and intI-bla(VIM-1)-aacA4-aadA1-qacEΔ1/sul1 (In488). Isolates belonging to three clones (A, F and G) harboured different types of integron (In624 or In488) despite belonging to the same clone. Conjugal experiments showed an association with a conjugative plasmid of ca. 300 kb belonging to IncHI2 group, which is common in Spanish hospitals, suggesting that the widespread dissemination of bla(VIM-1) may be due to horizontal transfer of mobile genetic determinants rather than the result of spreading of a few clones. These results have implications for infection control programmes in the hospital.

Could polymerase chain reaction tests on conjunctival swabs be useful to diagnose herpetic keratitis?

INTRODUCTION: Diagnosis of HSV-1 keratitis (HK) is frequently based on clinical findings. Invasive specimens (corneal scrapings, biopsies) are required for microbiological diagnosis. Methods Corneal scrapings and conjunctival swabs were collected on patients with/without clinical suspicion of HK from 2007 to 2012.ResultsThe sensitivity, specificity, positive and negative predictive values for conjunctival swabs by PCR was 77.8, 92.1, 84.4 and 88.3, respectively. Discussion Conjunctival swabs by PCR may help in the diagnosis of HK, despite the limited sensitivity

INTRODUCCIÓN: El diagnóstico de queratitis herpética (QH) está basado normalmente en hallazgos clínicos. Para el diagnóstico microbiológico se requieren muestras invasivas (raspado corneal, biopsias).MÉTODOS: Raspados corneales y exudados conjuntivales fueron obtenidos de pacientes con/sin sospecha clínica de QH del ano˜ 2007 al 2012.RESULTADOS: La sensibilidad, la especificidad y los valores predictivos positivos y negativos para la PCR enexudados conjuntivales fueron 77,8, 92,1, 84,4 y 88,3, respectivamente. DISCUSIÓN: La PCR en exudados conjuntivales puede ayudar en el diagnóstico, a pesar de su limitada sensibilidad

Could polymerase chain reaction tests on conjunctival swabs be useful to diagnose herpetic keratitis?

INTRODUCTION: Diagnosis of HSV-1 keratitis (HK) is frequently based on clinical findings. Invasive specimens (corneal scrapings, biopsies) are required for microbiological diagnosis. METHODS: Corneal scrapings and conjunctival swabs were collected on patients with/without clinical suspicion of HK from 2007 to 2012. RESULTS: The sensitivity, specificity, positive and negative predictive values for conjunctival swabs by PCR was 77.8, 92.1, 84.4 and 88.3, respectively. DISCUSSION: Conjunctival swabs by PCR may help in the diagnosis of HK, despite the limited sensitivity.

Relationship between agr dysfunction and reduced vancomycin susceptibility in methicillin-susceptible Staphylococcus aureus causing bacteraemia.

OBJECTIVES: Limited data exist regarding the role of agr dysfunction in reducing susceptibility to vancomycin in methicillin-susceptible Staphylococcus aureus (MSSA). This study investigated the clinical and molecular epidemiology of MSSA causing bacteraemia, with emphasis on the reduced susceptibility to vancomycin (RSV) phenotype (MIC ≥ 1.5 mg/L) and its relationship with agr dysfunction. METHODS: All MSSA bloodstream isolates obtained at our hospital during 2010 were analysed. Antimicrobial susceptibility was determined and time-kill experiments were performed for oxacillin. Multilocus sequence type and agr genotype were determined and DNA microarray analysis of virulence factors was performed. agr dysfunction was assessed phenotypically and by RT-PCR quantification of RNAIII. RESULTS: Of 84 MSSA, 55 (65.5%) exhibited the RSV phenotype, comprising 13 clonal complexes. agr II polymorphism was more prevalent in RSV than non-RSV isolates (41.8% versus 17.2%, P = 0.023) and average levels of RNAIII gene expression were higher in RSV than non-RSV isolates (ΔCt 4.05 ± 3.29 versus 1.5 ± 2.11, P = 0.005), implying greater agr dysfunction in RSV MSSA. CONCLUSIONS: We demonstrated a correlation between RSV phenotype in MSSA and reduced agr expression, particularly in association with the agr II genotype. These results may help to understand the role of agr dysfunction in the increased mortality in MSSA infections.

Colonización nasal por Staphylococcus aureus en estudiantes de medicina: importancia en la transmisión hospitalaria / Staphylococcus aureus nasal colonization in medical students: Importance in nosocomial transmission

INTRODUCCIÓN: Staphylococcus aureus es el principal patógeno causante de infecciones nosocomiales. Los profesionales sanitarios, incluyendo los estudiantes de medicina, pueden ser una fuente de transmisión. Los objetivos del estudio fueron determinar la tasa de portadores nasales de S. aureus sensible y resistente a la meticilina (SARM) y evaluar el conocimiento y la adherencia que tenían los estudiantes sobre la higiene de manos. Métodos En el estudio participaron estudiantes de medicina adscritos al Hospital Universitario 12 de Octubre. Se realizó la toma de muestras de ambos vestíbulos nasales, y en todos los aislamientos se determinó la sensibilidad antibiótica. La obtención de datos se realizó mediante una encuesta autoadministrada que incluía factores de riesgo de colonización, hábitos higiénicos y conocimiento del protocolo de higiene de manos. Resultados De los 140 estudiantes incluidos, se detectaron 55 (39,3%) colonizados por S. aureus, con 3 (2,1%) SARM. La exposición a los antibióticos en los últimos 3 meses fue menor en los estudiantes colonizados (12,3% vs. 25,9%, p = 0,03). La autoevaluación mostró que el 56,4% de los estudiantes no se lavaban las manos casi nunca antes de atender al primer paciente, y solo el 38,6% se lavaban siempre después de explorar a los pacientes. El 35,7% desconocían el protocolo de higiene de manos, y el 38,6% no habían recibido formación específica. Conclusiones Los estudiantes de medicina deben ser tenidos en cuenta en los programas de control de la infección hospitalaria. La formación sobre higiene de manos debería impartirse antes de que los estudiantes comenzasen sus prácticas en el hospital

BACKGROUND: Staphylococcus aureus is the main pathogen causing nosocomial infections. Health profesionals, including medical students, could be a source of transmission. The aims of the study were to determine the rate of nasal carriage of S. aureus susceptible and resistant to methicillin (MRSA) and evaluate the knowledge and adherence that students had about hand hygiene. METHODS: The study included medical students attached to the Hospital Universitario 12 de Octubre(Madrid, Spain). We collected samples from both nasal vestibules, and the antimicrobial susceptibility was determined on all isolates. Data collection was performed using a self-administered questionnaire that included risk factors for colonization, hygiene habits and knowledge of hand hygiene protocols. RESULTS: Of the 140 students included, 55 (39.3%) were colonized by S. aureus, and 3 (2,1%) by MRSA. The exposure to antibiotics in the last 3 months was lower in colonized students (12.3% vs. 25.9%, P = .03). Self-assessment showed that 56.4% of students almost never washed their hands before to attending to the first patient, and only 38.6% always washed after examining patients. More than a third (35.7%) ignored the hand hygiene protocol, and 38.6% had not received specific formation. CONCLUSIONS: Medical students should be included in hospital infection control programs. Hand hygiene training should be given to students before they begin their practices in the hospital

Draft Whole-Genome Sequence of VIM-1-Producing Multidrug-Resistant Enterobacter cloacae EC_38VIM1.

The VIM-1-producing multidrug-resistant strain Enterobacter cloacae was isolated from blood culture. The strain showed multiple resistances to clinically used antibiotics, including all ß-lactams, fluoroquinolones, aminoglycosides, and sulfonamides. Sequence analysis showed the presence of 14 genes associated with resistance to antibiotics, including the metallo-ß-lactamase VIM-1 gene, which was located in a class 1 integron.

Draft Genome Sequence of Strain SA_ST125_MupR of Methicillin-Resistant Staphylococcus aureus ST125, a Major Clone in Spain.

Here, we report the draft genome sequence of a methicillin-resistant Staphylococcus aureus (MRSA) strain with high-level mupirocin resistance (SA_ST125_MupR), isolated from a patient with recurrent bacteremia. This strain belonged to sequence type ST125, which was responsible for more than 50% of the health care-associated infections caused by MRSA in Spain.

Draft Genome Sequence of VIM-2-Producing Multidrug-Resistant Pseudomonas aeruginosa ST175, an Epidemic High-Risk Clone.

The VIM-2-producing multidrug-resistant high-risk clone Pseudomonas aeruginosa sequence type (ST) 175 was isolated in the setting of a large outbreak in Hospital Universitario 12 de Octubre (Spain) from 2007 to 2010. This strain was resistant to all ß-lactams, fluoroquinolones, and aminoglycosides, with the exception of amikacin, and has become an endemic clone in our institution.

Molecular characterization of Achromobacter isolates from cystic fibrosis and non-cystic fibrosis patients in Madrid, Spain.

Multilocus sequence typing and nrdA sequence analysis identified 6 different species or genogroups and 13 sequence types (STs) among 15 Achromobacter isolates from cystic fibrosis (CF) patients and 7 species or genogroups and 11 STs among 11 isolates from non-CF patients. Achromobacter xylosoxidans was the most frequently isolated species among CF patients.

Algorithm proposal based on the C. Diff Quik Chek Complete ICT device for detecting Clostridium difficile infection

Objective: To assess a new immunochromatography (ICT) test that detects glutamate dehydrogenase (GDH) antigen and Clostridium difficile toxin A/B simultaneously, and to propose an algorithm for the diagnosis of C. difficile infection (CDI) based on this test. Methods We analysed 970 stool samples. Discrepant results between GDH and toxin A/B were resolved using toxigenic culture as the reference. Results This test enabled us to obtain a conclusive result in <30min in 93.8% of the samples. Among the discrepant results (GDH (+)/Toxin A/B (-)), 41.7% (25/60) were found to be toxigenic C. difficile by toxigenic culture. Conclusion This test has a high sensitivity and specificity for the diagnosis of CDI (AU)

Objetivo: Evaluar una nueva prueba inmunocromatográfica que detecta el antígeno glutamato deshidrogenasa (GDH) y la toxina A/B de Clostridium difficile simultáneamente y proponer un algoritmo para el diagnóstico de infección por C. difficile (ICD) basado en esta prueba. Métodos: Se analizaron 970 muestras. Las discrepancias entre GDH y toxina A/B se resolvieron utilizando el cultivo toxigénico como método de referencia. Resultados: Esta prueba permitió obtener el resultado del 93,8% de las muestras en < 30 minutos. El 41,7%(25/60) de las muestras discrepantes (GDH (+)/Toxina A/B (-)) fueron C. difficile toxigénicos, mediante cultivo toxigénico. Conclusión: Esta prueba es sensible y específica para el diagnóstico de ICD (AU)

[Staphylococcus aureus nasal colonization in medical students: importance in nosocomial transmission]. / Colonización nasal por Staphylococcus aureus en estudiantes de medicina: importancia en la transmisión hospitalaria.

BACKGROUND: Staphylococcus aureus is the main pathogen causing nosocomial infections. Health professionals, including medical students, could be a source of transmission. The aims of the study were to determine the rate of nasal carriage of S.aureus susceptible and resistant to methicillin (MRSA) and evaluate the knowledge and adherence that students had about hand hygiene. METHODS: The study included medical students attached to the Hospital Universitario 12 de Octubre (Madrid, Spain). We collected samples from both nasal vestibules, and the antimicrobial susceptibility was determined on all isolates. Data collection was performed using a self-administered questionnaire that included risk factors for colonization, hygiene habits and knowledge of hand hygiene protocols. RESULTS: Of the 140 students included, 55 (39.3%) were colonized by S.aureus, and 3 (2,1%) by MRSA. The exposure to antibiotics in the last 3 months was lower in colonized students (12.3% vs. 25.9%, P=.03). Self-assessment showed that 56.4% of students almost never washed their hands before to attending to the first patient, and only 38.6% always washed after examining patients. More than a third (35.7%) ignored the hand hygiene protocol, and 38.6% had not received specific formation. CONCLUSIONS: Medical students should be included in hospital infection control programs. Hand hygiene training should be given to students before they begin their practices in the hospital.

Algorithm proposal based on the C. Diff Quik Chek Complete ICT device for detecting Clostridium difficile infection.

OBJECTIVE: To assess a new immunochromatography (ICT) test that detects glutamate dehydrogenase (GDH) antigen and Clostridium difficile toxin A/B simultaneously, and to propose an algorithm for the diagnosis of C. difficile infection (CDI) based on this test. METHODS: We analysed 970 stool samples. Discrepant results between GDH and toxin A/B were resolved using toxigenic culture as the reference. RESULTS: This test enabled us to obtain a conclusive result in <30min in 93.8% of the samples. Among the discrepant results (GDH (+)/Toxin A/B (-)), 41.7% (25/60) were found to be toxigenic C. difficile by toxigenic culture. CONCLUSION: This test has a high sensitivity and specificity for the diagnosis of CDI.

VIM-2-producing multidrug-resistant Pseudomonas aeruginosa ST175 clone, Spain.

A total of 183 patients were colonized or infected with multidrug-resistant Pseudomonas aeruginosa isolates at a hospital in Spain during 2007-2010; prevalence increased over this period from 2.8% to 15.3%. To characterize these isolates, we performed molecular epidemiologic and drug resistance analysis. Genotyping showed that 104 (56.8%) isolates belonged to a single major clone (clone B), which was identified by multilocus sequence typing as sequence type (ST) 175. This clone was initially isolated from 5 patients in 2008, and then isolated from 23 patients in 2009 and 76 patients in 2010. PCR analysis of clone B isolates identified the bla(VIM-2) gene in all but 1 isolate, which harbored bla(IMP-22). ST175 isolates were susceptible to only amikacin (75%) and colistin (100%). Emergence of the ST175 clone represents a major health problem because it compromises therapy for treatment of P. aeruginosa nosocomial infections.

Long-term evolution of multiple outbreaks of Serratia marcescens bacteremia in a neonatal intensive care unit.

The annual incidence of Serratia marcescens bacteremia in a neonatal intensive care unit increased significantly between 2002 and 2010. Molecular epidemiology studies revealed that 8 clones were responsible for 85.2% of cases. Given that these infections are potentially preventable, even the appearance of 1 case of bacteremia should be an indicator for outbreak management.

Lack of the detection of XMRV or polytropic MLV-related sequences in blood cells from HIV-1-infected patients in Spain.

BACKGROUND: Xenotropic murine leukemia virus-related virus (XMRV) and polytropic murine leukemia virus (MLV)-related virus are recently described human gammaretroviruses that have been associated with prostate cancer and chronic fatigue syndrome. These studies have been controversial because a number of laboratories have been unable to find evidence of XMRV in similar groups of patients or controls. Because the existence of XMRV raises many questions, we decided to study its presence in a group of patients infected with HIV-1 with a high proportion of intravenous drug use and coinfection by hepatitis C virus. METHODS: Forty HIV-1-infected patients under follow-up in our institution were screened for XMRV/MLV by nested polymerase chain reaction using primers targeting the gag and env region. Specific primers for mouse mitochondrial DNA were used to rule out contamination. RESULTS: No evidence of XMRV or polytropic MLV-related sequences was found in any sample from patients or controls. Four samples yielded polymerase chain reaction bands whose sequence corresponded to murine endogenous retroviral sequences, however, contamination with mouse cell DNA was subsequently confirmed. CONCLUSIONS: XMRV/MLV viruses do not seem to be associated with HIV-1 infection or intravenous drug use. Contamination of samples or reagents by genomic murine DNA or XMRV vectors could account for the sporadic detection of positive samples for XMRV and related agents.

Multidrug-resistant Acinetobacter baumannii Harboring OXA-24 carbapenemase, Spain.

In February 2006, a patient colonized with a multidrug-resistant sequence type 56 Acinetobacter baumannii strain was admitted to a hospital in Madrid, Spain. This strain spread rapidly and caused a large outbreak in the hospital. Clinicians should be alert for this strain because its spread would have serious health consequences.

High vancomycin MIC and complicated methicillin-susceptible Staphylococcus aureus bacteremia.

We conducted a retrospective study of 99 patients with methicillin-suseptible Staphylococcus aureus catheter-related bacteremia in which vancomycin MIC was determined by Etest. High vancomycin MIC (>1.5 ug/mL) was the only independent risk factor for development of complicated bacteremia caused by methicillin-susceptible S. aureus (odds ratio 22.9, 95% confidence interval 6.7-78.1).