Antimicrobial resistance, virulence factors and genetic lineages of hospital-onset methicillin-resistant Staphylococcus aureus isolates detected in a hospital in Zaragoza / Resistencia a antibióticos, factores de virulencia y líneas clonales de Staphylococcus aureus resistente a la meticilina de origen hospitalario en un hospital de Zaragoza

INTRODUCTION: MRSA population dynamics is undergoing significant changes, and for this reason it is important to know which clones are circulating in our nosocomial environment. MATERIALS AND METHODS: A total of 118 MRSA isolates were collected from clinical samples from patients with previous hospital or healthcare contact (named as hospital-onset MRSA (HO-MRSA)) during a one year period. Susceptibility testing was performed by disk diffusion and microdilution. The presence of resistance genes and virulence factors were tested by PCR. All isolates were typed by SCCmec, spa and agr typing. PFGE and MLST were applied to a selection of them. RESULTS: Eighty-three HO-MRSA isolates (70.3%) were resistant to any antibiotic included in the macrolide-lincosamide-streptogramin B group. Among these isolates, the M phenotype was the most frequent (73.5%). One hundred and seven of HO-MRSA isolates (90.7%) showed aminoglycoside resistance. The combination aac(6')-Ie-aph(2'')-Ia + ant(4')-Ia genes was the most frequent (22.4%). Tetracycline resistance rates in HO-MRSA isolates were low (3.4%), although a high level of mupirocin resistance was observed (25.4%). Most of the HO-MRSA isolates (approximately 90%) showed SCCmec type IVc and agr type II. Fifteen unrelated pulsotypes were identified. CC5 was the most prevalent (88.1%), followed by CC8 (5.9%), CC22 (2.5%), CC398 (2.5%) and CC1 (0.8%). CONCLUSION: CC5/ST125/t067 lineage was the most frequent. This lineage was related to aminoglycoside resistance, and to a lesser extent, with macrolide resistance. The presence of international clones as EMRSA-15 (CC22/ST22), European clones as CC5/ST228, community clones related to CC1 or CC8 and livestock associated clones, as CC398, were observed in a low percentage

INTRODUCCIÓN: Las dinámicas poblacionales de SARM están experimentando cambios significativos en los últimos tiempos. Por ello es importante conocer qué líneas clonales circulan en nuestro ambiente hospitalario. MATERIALES Y MÉTODOS: Durante un año, se seleccionaron 118 SARM de muestras clínicas de pacientes con contacto previo con el ambiente hospitalario (SARM de origen hospitalario [SARM-OH]). Las pruebas de sensibilidad se realizaron mediante difusión con discos y microdilución. La presencia de genes de resistencia y factores de virulencia fueron estudiados mediante PCR. Se estableció el tipo de SCCmec, spa y agr en todos los aislados, y en una selección se estudió su relación genética por PFGE y MLST. RESULTADOS: Ochenta y tres SARM-OH (70,3%) fueron resistentes a al menos un antibiótico del grupo de los macrólidos-lincosamidas-estreptograminas B. Entre estos, el fenotipo M fue el más frecuente (73,5%). Ciento siete aislamientos (90,7%) mostraron resistencia a aminoglucósidos. La combinación aac(6')-Ieaph( 2'')-Ia + ant(4')-Ia fue la más frecuente (22,4%). Las tasas de resistencia a tetraciclinas detectadas fueron bajas (3,4%). Se observó un 25,4% de resistencia de alto nivel a mupirocina. Aproximadamente un 90% de SARM-OH mostraron SCCmec tipo IVc y agr tipo II. Se identificaron 15 pulsotipos no relacionados. El CC5 fue el más prevalente (88,1%) seguido de CC8 (5,9%), CC22 (2,5%), CC398 (2,5%) y CC1 (0,8%). CONCLUSIÓN: La línea clonal CC5/ST125/t067 fue la más habitual. Esta línea se relacionó con resistencia a aminoglucósidos, y, en menor medida, con macrólidos. La presencia de clones internacionales como EMRSA-15 (CC22/ST22), clones europeos como CC5/ST228, clones comunitarios relacionados con CC1 o CC8 y clones asociados al ganado, como el CC398, se observaron en un bajo porcentaje

Antimicrobial resistance, virulence factors and genetic lineages of hospital-onset methicillin-resistant Staphylococcus aureus isolates detected in a hospital in Zaragoza.

INTRODUCTION: MRSA population dynamics is undergoing significant changes, and for this reason it is important to know which clones are circulating in our nosocomial environment. MATERIALS AND METHODS: A total of 118 MRSA isolates were collected from clinical samples from patients with previous hospital or healthcare contact (named as hospital-onset MRSA (HO-MRSA)) during a one year period. Susceptibility testing was performed by disk diffusion and microdilution. The presence of resistance genes and virulence factors were tested by PCR. All isolates were typed by SCCmec, spa and agr typing. PFGE and MLST were applied to a selection of them. RESULTS: Eighty-three HO-MRSA isolates (70.3%) were resistant to any antibiotic included in the macrolide-lincosamide-streptogramin B group. Among these isolates, the M phenotype was the most frequent (73.5%). One hundred and seven of HO-MRSA isolates (90.7%) showed aminoglycoside resistance. The combination aac(6')-Ie-aph(2″)-Ia+ant(4')-Ia genes was the most frequent (22.4%). Tetracycline resistance rates in HO-MRSA isolates were low (3.4%), although a high level of mupirocin resistance was observed (25.4%). Most of the HO-MRSA isolates (approximately 90%) showed SCCmec type IVc and agr type II. Fifteen unrelated pulsotypes were identified. CC5 was the most prevalent (88.1%), followed by CC8 (5.9%), CC22 (2.5%), CC398 (2.5%) and CC1 (0.8%). CONCLUSION: CC5/ST125/t067 lineage was the most frequent. This lineage was related to aminoglycoside resistance, and to a lesser extent, with macrolide resistance. The presence of international clones as EMRSA-15 (CC22/ST22), European clones as CC5/ST228, community clones related to CC1 or CC8 and livestock associated clones, as CC398, were observed in a low percentage.

Influencia de la edad en la enfermedad neumocócica invasiva y en la resistencia a antimicrobianos / Influence of age on the clinical manifestations of invasive pneumococcal disease and antibiotic resistance rates

Fundamento y objetivo: La enfermedad invasiva por Streptococcus pneumoniae (EISP) presenta variaciones epidemiológicas en relación con la edad y el serotipo de neumococo aislado. Los objetivos del trabajo fueron analizar las formas clínicas y la mortalidad de EISP, los serotipos aislados y la tasa de resistencia a antimicrobianos en diferentes grupos de edad. Pacientes y método: Se estudiaron 141 pacientes con EISP diagnosticados entre 2002 y 2008 y se clasificaron en 4 grupos: ≤ 2 años, 3-14 años, 15-64 años y ≥ 65 años. Resultados: La neumonía que la manifestación más frecuente (71%) en todos los grupos de edad. En el grupo ≤ 2 años destacó una mayor prevalencia de meningitis (28 frente a 9%, p = 0,054) y en el grupo 3-14 años el empiema fue más frecuente (31 frente a 5%, p < 0,001). La mortalidad se asoció con la edad ≥ 65 años (odds ratio [OR] 7, intervalo de confianza del 95% [IC 95%] 1,9-28,9), la bacteriemia primaria (OR 7, IC 95% 1,9-28,9) y la intubación orotraqueal (OR 9, IC 95% 1,9-41,1). Los serotipos más prevalentes en ≤ 2 años fueron 14, 19A y 19F, el serotipo 1 en el grupo 3-14 años y el 3 en ≥ 65 años. En la población pediátrica se observó una mayor tasa de cepas no sensibles a penicilina (42 frente a 18%, p = 0,007). Conclusiones: La edad se relacionó con las formas clínicas, la mortalidad y la resistencia a antimicrobianos. La bacteriemia primaria constituyó uno de los factores asociados con una mayor mortalidad (AU)

Background and objective: Invasive pneumococcal disease (IPD) shows different epidemiological characteristics depending on age and pneumococcus serotype. The aims of the work were to analyze the clinical manifestations and mortality associated with IPD, the serotype isolated and the antibiotic resistance rates in different age groups. Patients and method: Retrospectively, 141 patients with IPD diagnosed between 2002 and 2008 were studied. Patients were classified in 4 age groups: 2 year-old, 3-14 year-old, 15-64 year-old and 65 year-old. Results: Pneumonia was the most common manifestation in all age groups (71%). Pneumococcal meningitis was more prevalent in patients 2 year-old (28 vs. 9%, P = .054) and empyema was more frequent in those between 3-14 year-old (31 vs. 5%, P < .001). Mortality was associated with age 65 year-old (odds ratio [OR] 7, 95% confidence interval [95% CI] 1.9-28.9), primary bacteremia (OR 7, 95% CI 1.9-28.9) and orotracheal intubation (OR 9, 95% CI 1.9-41.1). The more prevalent serotypes among patients 2 year-old were 14, 19A and 19F. The serotype 1 was most common in patients between 3-14 year-old and serotype 3 in those 65 year-old. A higher rate of non-susceptible penicillin strains was observed in pediatric population (42 vs. 19%, P = .007). Conclusions: Age was related to the clinical manifestations, mortality and antibiotic resistance rates. Primary bacteremia was one of the risk factors of mortality (AU)

Usefulness of PCR-RFLP coa gene for clonal classification of methicillin-resistant Staphylococcus aureus isolates in tertiary hospitals.

One hundred and one methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates were classified into 10 genotypes based on their polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) coa pattern. PCR-RFLP coa patterns correlated with the clonal complex (CC) with the exception of CC5, which was related to 2 patterns (B and E). The PCR-RFLP coa gene technique provides a useful preliminary method to monitor variations in MRSA populations.

[Influence of age on the clinical manifestations of invasive pneumococcal disease and antibiotic resistance rates]. / Influencia de la edad en la enfermedad neumocócica invasiva y en la resistencia a antimicrobianos.

BACKGROUND AND OBJECTIVE: Invasive pneumococcal disease (IPD) shows different epidemiological characteristics depending on age and pneumococcus serotype. The aims of the work were to analyze the clinical manifestations and mortality associated with IPD, the serotype isolated and the antibiotic resistance rates in different age groups. PATIENTS AND METHOD: Retrospectively, 141 patients with IPD diagnosed between 2002 and 2008 were studied. Patients were classified in 4 age groups: ≤ 2 year-old, 3-14 year-old, 15-64 year-old and ≥ 65 year-old. RESULTS: Pneumonia was the most common manifestation in all age groups (71%). Pneumococcal meningitis was more prevalent in patients ≤ 2 year-old (28 vs. 9%, P=.054) and empyema was more frequent in those between 3-14 year-old (31 vs. 5%, P<.001). Mortality was associated with age ≥ 65 year-old (odds ratio [OR] 7, 95% confidence interval [95% CI] 1.9-28.9), primary bacteremia (OR 7, 95% CI 1.9-28.9) and orotracheal intubation (OR 9, 95% CI 1.9-41.1). The more prevalent serotypes among patients ≤ 2 year-old were 14, 19A and 19F. The serotype 1 was most common in patients between 3-14 year-old and serotype 3 in those ≥ 65 year-old. A higher rate of non-susceptible penicillin strains was observed in pediatric population (42 vs. 19%, P=.007). CONCLUSIONS: Age was related to the clinical manifestations, mortality and antibiotic resistance rates. Primary bacteremia was one of the risk factors of mortality.

Influence of glutathione S-transferase M1 and T1 homozygous null mutations on the risk of antituberculosis drug-induced hepatotoxicity in a Caucasian population.

OBJECTIVES: Genetic variations in enzymes of isoniazid metabolism confer an increased risk for antituberculosis drug-induced hepatotoxicity in Asian populations. The present study was aimed at investigating the possible association of antituberculosis drug-induced hepatotoxicity with polymorphisms at the glutathione S-transferase (GST) gene in a Caucasian population. METHODS: A prospective case-control study was nested in a cohort of patients with active tuberculosis who were treated with a combination of isoniazid, rifampicin and pyrazinamide. Cases constituted patients with antituberculosis drug-induced hepatotoxicity (n=35), and controls constituted patients without any evidence of this complication (n=60). Homozygous null polymorphisms at GST loci M1 and T1 were analysed from genomic DNA from all participants. RESULTS: The GSTT1 homozygous null polymorphism was significantly associated with antituberculosis drug-induced hepatotoxicity [odds ratio (OR) 2.60, 95% confidence interval (CI) 1.08-6.24, P=0.03]. No significant association was observed between the GSTM1 homozygous null polymorphism and antituberculosis drug-induced hepatotoxicity (OR 0.73, 95% CI 0.31-1.73, P=0.48). CONCLUSION: The GSTT1 homozygous null polymorphism may be a risk factor of antituberculosis drug-induced hepatotoxicity in Caucasians.