Salmonella isolates from urine cultures: serotypes and antimicrobial resistance in hospital settings.

This study investigated the serotypes and antimicrobial resistance of Salmonella isolates in urine cultures from 38 hospitalized patients. Nine serotypes were detected, and a large proportion was Typhimurium and Enteritidis. The strains presented resistance to 11 different antibiotics. Thirteen isolates (11 from serotype Typhimurium) exhibited multidrug resistance.

Salmonelosis extraintestinal: clínica, epidemiología y resistencia antimicrobiana / Salmonella extraintestinal infection: clinic features, epidemiology and antimicrobial resistance

Se evaluaron retrospectivamente las características clínicas de 59 pacientes con aislamientos extraintestinales de Salmonella enterica no Typhi y la resistencia antibiótica entre 1988 y 2004. En el 95% de los casos se conocieron las condiciones de base del huésped que consistieron en: enfermedad oncohematológica (15), lupus eritematoso sistémico (11), síndrome de inmuno deficiencia adquirida (10), pacientes internados en neonatología (8), colecistitis (4) y otras (7). Las formas clínicas halladas fueron: bacteriemias primarias (26), bacteriemias secundarias a gastroenteritis (15), artritis séptica (7), infección urinaria (12), infección intraabdominal (5), meningitis (1) y pericarditis (1). En 29 pacientes se aisló Salmonella enterica no Typhi en más de una localización. El 15,8% y el 21,0% de 59 aislamientos presentaron resistencia a cefalosporinas de 3ª generación y a ampicilina, respectivamente. Salmonella Agona causó un brote epidémico en la sala de cuidados intensivos de neonatología, aislándose de sangre en 5 pacientes y en uno también de LCR. Este serotipo fue multirresistente. Imipenem, trimetroprima-sulfometoxazol y ciprofloxacina fueron los antibióticos más activos (CIM 50: 0,5; 0,5 y 0,002 µg/mL, respectivamente).

The clinical and antimicrobial resistance of 59 patients with extraintestinal infection by nontyphi Salmonella was retrospectively evaluated from 1988 to 2004. In 95% of the patients there were underlying diseases, which included: oncohematologic disease (15), systemic lupus erythematosus (11), acquired immunodeficiency disease (AIDS) (10), patients of neonatal units (8), colecistitis (4), and other disorders (7). The clinical manifestation were primary bacteremias (26), bacteremias secondary to gastroenteritis (15), arthritis (7), urinary tract infections (12), abdominal infections (5), meningitis (1) and pericarditis (1). In 29 patients Salmonella enterica no Typhi was isolated in more than one site. Resistance to third generation cephalosporins was observed in 15,8 % of these isolates, and resistance to ampicillin in 21,0%. Salmonella Agona was isolated from an outbreak in neonatal ICU; the organism was recovered from blood samples of five neonates and in one patient also isolated from CSF. These isolates showed multiresistance. Imipenem, trimetoprim-sulfametoxazol and ciprofloxacin were the three most active antimicrobial agents (MIC 50: 0.5, 0.5 and 0.002 µg/mL, respectively).

dfrA25, a novel trimethoprim resistance gene from Salmonella Agona isolated from a human urine sample in Brazil.

OBJECTIVES: To describe a novel trimethoprim resistance gene, designated dfrA25, which was detected as a gene cassette within a class 1 integron in Salmonella Agona. METHODS: The gene was cloned into Escherichia coli MT102 and resistance to 10 different antimicrobial drugs was measured. A phylogenetic tree was constructed based on representative trimethoprim-resistance-mediating DfrA proteins retrieved from GenBank. Filter-mating experiments and Southern blots of plasmid preparations were performed with the donor and selected transconjugants. RESULTS AND CONCLUSIONS: dfrA25 encodes a dihydrofolate reductase of 157 amino acids with closest identity (85%) to dfrA5 dihydrofolate reductase. dfrA25 was located on a transferable plasmid (approximately 150 kb) that also harboured the tetracycline resistance gene tet(A).