Introducción. Actualmente se considera a Enterococcus spp. como uno de los agentes de infección hospitalaria más importantes, siendo su resistencia a los antibióticos un problema importante en los centros de salud. Objetivos. Caracterizar la resistencia antimicrobiana en 50 cepas de Enterococcus spp. aisladas de muestras clínicas de pacientes hospitalizados . Materiales y métodos. Se llevó a cabo un estudio de tipo descriptivo observacional de corte transversal en 50 aislamientos clínicos de estas especies microbianas. Se trabajó un aislamiento por paciente. La identificación y la sensibilidad a los antibióticos se realizaron por métodos automatizados y convencionales. El análisis fenotípico de los mecanismos de resistencia a glucopéptidos se hizo según las recomendaciones de la Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. Resultados. De 50 aislamientos, 30 (60,0 %) y 20 (40,0 %) pertenecían a las especies de Enterococcus faecalis y Enterococcus faecium , respectivamente. La resistencia global expresada por este género fue de 38/50 (76,0 %) para ampicilina; 33/50 (66,0 %) para gentamicina de alto nivel; 34/50 (68,0 %) para estreptomicina de alto nivel; 26/50 (52,0 %) para ciprofloxacina; 4/50 (8,0 %) para linezolid; 17/50 (34,0 %) para teicoplanina; 25/50 (50,0 %) para vancomicina; 31/50 (62,0 %) para minociclina; 34/50 (68,0 %) para tetraciclina y 9/50 (18,0 %) para nitrofurantoina. Frente a los glucopéptidos, 25/50 (50,0 %) y 10/50 (20,0 %) de los aislamientos presentaron los mecanismos Van A y Van B, respectivamente. Conclusiones. Podemos concluir que la mayoría de las veces, las cepas aisladas en el Hospital Hermanos Ameijeiras mostraron porcentajes de resistencia por encima de lo reportado en la literatura científica consultada. El alto porcentaje de cepas con resistencia a la vancomicina podría influir en la aparición de otros gérmenes Gram positivos con resistencia a este fármaco. Se reporta por primera vez en un hospital cubano resistencia de E. faecium a linezolid.

Introduction: Enterococcus spp is currently considered as one of the most important nosocomial pathogens . The antibiotic resistance of this group of bacteria is a particularly important problem in health centers. Objective: To characterize the antibiotic resistance of 50 Enterococcus spp strains isolated from hospitalized patients clinical samples. Materials and methods: We conducted a cross-sectional descriptive observational study in 50 clinical isolates of Enterococcus spp. Only one isolate per patient was analyzed . The identification and antibiotic susceptibility were studied by conventional and automated methods . The phenotypic analysis of glycopeptide resistance mechanisms was performed as recommended by the Spanish Society of Clinical Microbiology and Infectious Diseases . Results: Of 50 isolates obtained from clinical samples, 30 ( 60.0%) belonged to Enterococcus faecalis and 20 (40.0 %) to Enterococcus faecium . The global resistance expressed by this genre was as follows: Ampicillin, 38/50 ( 76.0%); high-level gentamicin , 33/50 ( 66.0%); high-level streptomycin, 34/50 (68.0 %) ; ciprofloxacin, 26/50 (52.0 %); linezolid, 4/50 (8.0 %); teicoplanin, 17/50 ( 34.0%); vancomycin, 25/50 (50.0 %); minocycline, 31/50 ( 62.0%); tetracycline, 34/50 (68.0 %); nitrofurantoin, 9/50 ( 18.0%). As regards glycopeptides, 25/50 (50.0%) showed a Van A mechanism and 10/50 (20.0 %) a Van B mechanism . Conclusions: The isolates obtained at Hospital Hermanos Ameijeiras showed higher resistance rates than those reported in the consulted literature. The high percentage of vancomycin-resistant strains might have influenced the development of other Gram-positive bacteria resistant to this drug. This is the first report on Enterococcus faecium resistant to linezolid in a Cuban hospital.

INTRODUCTION: Nosocomial pneumonia associated with use of mechanical ventilators is one of the greatest challenges confronted by intensivists worldwide. The literature associates several bacteria with this type of infection; most common in intensive care units are Acinetobacter baumannii, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and some of the Enterobacteriaceae family. OBJECTIVES: To identify the causal agents of nosocomial ventilatorassociated pneumonia in patients receiving mechanical ventilation in the intensive care units of Havana's Hermanos Ameijeiras Clinical-Surgical Teaching Hospital in 2011, and to characterize their antibiotic resistance. METHODS: A cross-sectional descriptive study was conducted using hospital administrative data of quantitative cultures from positive tracheal aspirates for January through December, 2011. Records were analyzed from 77 intensive care unit patients who developed nosocomial ventilator-associated pneumonia. Variables examined were age and sex, and pathogens identified from culture of tracheal aspirate and related antibiotic susceptibility. RESULTS: Species most frequently isolated were: Acinetobacter baumannii in 53 patients (68.8%), Pseudomonas aeruginosa in 34 patients (44.2%), other species of Pseudomonas in 15 patients (19.5%), and Serratia marcescens, Klebsiella pneumoniae, and Escherichia coli in 12 patients each (15.6%). Some patients presented more than one pathogen in concurrent or successive infections. Antimicrobial susceptibility testing found high percentages of resistance to antibiotics in all these pathogens. Least resistance was found to colistin. CONCLUSIONS: The prevalence of antibiotic resistance in bacteria causing nosocomial ventilator-associated pneumonia is of concern. Colistin is the drug of choice among the antibiotics reviewed, but sensitivity to other antibiotics should be assessed to search for more appropriate broad-spectrum antibiotics for treating nosocomial ventilator-associated pneumonia. Our results also suggest the need to strengthen infection control efforts, particularly in intensive care units, and to reassess compliance with quality control procedures. Multidisciplinary research involving microbiologists, epidemiologists, internists and intensivists is needed to fully understand the etiological and resistance patterns observed.

OBJECTIVE: To characterize mechanical ventilation-associated pneumonia (MVAP). METHOD: This is an observational descriptive study to characterize MVAP in 61 ventilated patients admitted in the intensive care units of the Hermanos Ameijeiras hospital during 2011. This study also aimed to isolate the bacteria causing MVAP and characterize their resistance to antibiotics. RESULTS: 51 (83.60%) patients presented pulmonary infiltrates and 35 (50.81%) presented a clinical score > 6 according to the Clinical Pulmonary Infection Score. Acinetobacter baumannii and Pseudomonas aeruginosa were the most frequently isolated microorganisms from patients with MVAP. Both microorganisms showed a high resistance to antibiotics. Carbapenems were the most frequent used antimicrobial therapeutic agents; elective antibiotic combinations were directed against both bacterial wall structure and nucleic acid synthesis. CONCLUSION: Patients with MVAP identified during the studied period showed similar frequency to those reported in medical literature. Thus, this study corroborated that this is still a relevant medical problem in this hospital. Acinetobacter baumannii and Pseudomonas aeruginosa were the most frequently isolated microorganisms from patients with MVAP. Antimicrobial treatment, empirical or not, are still the main risk factors for the development of multidrug-resistant strains of bacteria. The rate of resistance to antibiotics of Acinetobacter baumannii and Pseudomonas aeruginosa strains isolated from patients with MVAP was higher than those isolated from infected patients without MAVP. Tigecycline and colistin were the only antibiotics fully effective against Acinetobacter baumannii strains isolated in 2011 from patients with MVAP; against Pseudomonas aeruginosa strains, only colistin was fully effective.