RESUMEN
A case-case-control study was conducted to identify independent risk factors for recovery of Escherichia coli strains producing CTX-M-type extended-spectrum ß-lactamases (CTX-M E. coli) within a large Southeastern Michigan medical center. Unique cases with isolation of ESBL-producing E. coli from February 2010 through July 2011 were analyzed by PCR for blaCTX-M, blaTEM, and blaSHV genes. Patients with CTX-M E. coli were compared to patients with E. coli strains not producing CTX-M-type ESBLs (non-CTX-M E. coli) and uninfected controls. Of 575 patients with ESBL-producing E. coli, 491 (85.4%) isolates contained a CTX-M ESBL gene. A total of 319 (84.6%) patients with CTX-M E. coli (282 [74.8%] CTX-M-15 type) were compared to 58 (15.4%) non-CTX-M E. coli patients and to uninfected controls. Independent risk factors for CTX-M E. coli isolation compared to non-CTX-M E. coli included male gender, impaired consciousness, H2 blocker use, immunosuppression, and exposure to penicillins and/or trimethoprim-sulfamethoxazole. Compared to uninfected controls, independent risk factors for isolation of CTX-M E. coli included presence of a urinary catheter, previous urinary tract infection, exposure to oxyimino-cephalosporins, dependent functional status, non-home residence, and multiple comorbid conditions. Within 48 h of admission, community-acquired CTX-M E. coli (n = 51 [16%]) and non-CTX-M E coli (n = 11 [19%]) strains were isolated from patients with no recent health care contacts. CTX-M E. coli strains were more resistant to multiple antibiotics than non-CTX-M E. coli strains. CTX-M-encoding genes, especially bla(CTX-M-15) type, represented the most common ESBL determinants from ESBL-producing E. coli, the majority of which were present upon admission. Septic patients with risk factors for isolation of CTX-M E. coli should be empirically treated with appropriate agents. Regional infection control efforts and judicious antibiotic use are needed to control the spread of these organisms.
Asunto(s)
Infecciones por Escherichia coli/epidemiología , Proteínas de Escherichia coli/metabolismo , Escherichia coli/aislamiento & purificación , beta-Lactamasas/metabolismo , Anciano , Anciano de 80 o más Años , Atención Ambulatoria , Estudios de Casos y Controles , Ciprofloxacina/farmacología , Infecciones Comunitarias Adquiridas/microbiología , Farmacorresistencia Bacteriana Múltiple , Escherichia coli/efectos de los fármacos , Escherichia coli/enzimología , Escherichia coli/genética , Infecciones por Escherichia coli/tratamiento farmacológico , Proteínas de Escherichia coli/genética , Femenino , Genes Bacterianos , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Combinación Trimetoprim y Sulfametoxazol/farmacología , Estados Unidos/epidemiología , Catéteres Urinarios/microbiología , Infecciones Urinarias/microbiología , beta-Lactamasas/genéticaRESUMEN
Fever is a common problem for which patients seek medical advice. Fortunately, in most cases, fever is self-limiting or the etiology of fever is promptly established. Sustained, unexplained fever despite a comprehensive work up is recognized as fever of unknown origin (FUO), which frequently poses a clinical challenge. For a methodical approach, FUO is recently categorized into classic FUO, nosocomial FUO, neutropenic FUO and HIV-associated FUO based on the clinical setting and patient's underlying immune status. This review focuses on the key factors of classic FUO. The etiologic clues obtainable from the history, bedside physical examination findings and pertinent laboratory tests are discussed. Also, FUO in older patients and tuberculosis as a cause of FUO are briefly discussed.