Carriage frequency, phenotypic and genotypic characteristics of Staphylococcus aureus isolated from dialysis and kidney tranplant patients at a hosptial in northern Paraná

The objective of the present study was to determine the frequency of Staphylococcus aureus nasal carriage among dialysis and kidney transplant patients, to identify the antimicrobial resistance profile of these strains and to verify their genetic profiles with the RW3A primer. The study included 159 individuals, comprising 111 dialysis and 48 kidney transplant patients. Of the 48 transplant patients, 75% were positive for S. aureus, whereas 49% of the 111 dialysis patients were carriers. Two samples yielded conflicting results for oxacillin sensitivity between the disk diffusion and minimum inhibitory concentration (MIC) assays: both were sensitive by the disk diffusion assay and resistant by MIC (4 μg/ml). In the antibiogram by disk diffusion, ten samples were resistant to cefoxitin, among which eight were also resistant to oxacillin. The resistance of the ten samples to cefoxitin by the disk diffusion assay was confirmed by MIC. Of the ten oxacillin-resistant samples, eight harbored the mecA gene. All samples were sensitive to vancomycin, and most were resistant to penicillin and demonstrated high rates of resistance to the other antimicrobials tested. The samples from dialysis patients exhibited a more homogenous genetic profile. Among the samples with a high percent similarity, no correlation with sensitivity or resistance to oxacillin was observed. According to the results of this study, the implementation of prevention and control measures, such as increased restrictions on prescriptions for antimicrobial drugs and nasal decontamination prior to high-risk procedures, is recommended.

Portadores nasales de Staphylococcus aureus en personal que labora en un Hospital de Santander / Nasal carriers of Staphylococcus aureus in the personnel that works in a Hospital of Santander

Introducción: Las infecciones intrahospitalarias constituyen un problema de salud pública mundial, la diseminación de bacterias patógenas a partir del personal de salud, ha sido el enfoque de numerosas investigaciones que buscan mejorar la calidad de vida de los pacientes. Objetivo: Determinar la frecuencia de portadores de Staphylococcus aureus en fosas nasales del personal que labora en las unidades de cuidados intensivos, infectología pediátrica y lactario en un Hospital en Santander. Metodología: Se estudiaron muestras provenientes de fosas nasales de 87 trabajadores del Hospital. Las cepas aisladas se identificaron mediante las pruebas bioquímicas y posteriormente, se determinó el perfil de susceptibilidad ante diferentes antibióticos, se realizó test D a las cepas de S. aureus. Resultados: La frecuencia de portadores de bacterias patógenas fue 41,4%; el patógeno aislado con mayor frecuencia fue S. aureus (72%), donde el porcentaje de S. aureus meticilino-resistentes (SARM) fue de 11,6%, Enterobacter aerogenes (6%), Proteus mirabilis (2,3%), Haemophylus influenzae (1,1%), Citrobacter koseri (1,1%) y Providencia rettgeri (1,1%). Conclusión: S. aureus es el agente aislado con mayor frecuencia de las fosas nasales del personal de salud y la presencia de SARM es preocupante por su resistencia a los antibióticos, lo que dificulta su tratamiento. Este hecho evidencia la necesidad de actuar con un carácter preventivo, en el cual el control de portadores es crítico y debe asociarse con medidas de bioseguridad que establezcan barreras más eficientes, para reducir la diseminación del microorganismo y la ocurrencia de infecciones intrahospitalarias. Salud UIS 2011; 43 (2): 111-117.

Introduction: Nosocomial infections are a public health problem worldwide, its spread start from health personnel carrier of pathogenic bacteria, it has been the focus of a large number of research to improve the quality of life of the patients. Objective: To determine the frequency of nasal carriers of Staphylococcus aureus in the personnel that works in intensive care units (adults ICU and pediatric ICU), pediatric infectology and lactary in a Hospital in Santander. Methodology: Nasal samples from 87 workers from of the Hospital were studied. Isolated strains were identified by the corresponding biochemical tests and subsequently determined their susceptibility profiles to different antibiotics and test D for S. aureus. Results: The frequency of nasal carriers of pathogenic bacteria was 41.4%; it was found that S. aureus was the most isolated pathogenic microorganism, with a frequency of (72%). The percentage of meticilin resistant S. aureus (MRSA) was 11.6% , Enterobacter aerogenes (6%), Proteus mirabilis (2.3%); Haemophylus influenzae (1.1%); Citrobacter koseri (1.1%) and Providencia rettgeri (1.1%). Conclusion: S. aureus is the most frequently isolated agent in health personnel's nasal nostrils and the presence of MRSA is worrying, additionally, it presents characteristic of resistance to antibiotics, making harder its treatment. This fact evidences the necessity to act with a preventive character, in which the control of carriers is critical and it should be associated with biosecurity measures to establish effective barriers to reduce the dissemination of the microorganism and occurrence of nosocomial infections. Salud UIS 2011; 43 (2): 111-117.