title: Biofilm Formation and Susceptibility to Polymyxin B by a Highly Prevalent Clone of Multidrug-Resistant Acinetobacter baumannii from a Mexican Tertiary Care Hospital.
abstract: BACKGROUND
  Acinetobacter baumannii has emerged as a major cause of hospital-associated infections with increased morbidity and mortality among those affected.
  
  
  METHODS
  A total of 85 isolates of a highly prevalent multidrug-resistant clone, identified during the period 2007-2011, were analyzed for biofilm formation on a polystyrene surface. The minimal inhibitory concentration was determined by the Sensititre System, the agar disk diffusion method and then read by means of the BIOMIC system and serial dilutions on Müller-Hinton agar.
  
  
  RESULTS
  In this study, covering a period of 5 years (2007-2011), we demonstrate that a particular clone emerged as the most prevalent, with an associated lethality of 28.2%. We demonstrate that 92.9% of strains corresponding to this clone are biofilm producers. Our results also demonstrate that all isolates were 100% susceptible to polymyxin B.
  
  
  CONCLUSIONS
  Our study suggests that the high prevalence and lethality of this multidrug-resistant clone of A. baumannii and its persistence over close to 5 years in a Mexican tertiary hospital environment can be explained in part by the ability of these clinical isolates of A. baumannii to form biofilms.
authors.forename: Roberto
authors.initials: R
authors.lastname: Rosales-Reyes
authors.forename: María Dolores
authors.initials: MD
authors.lastname: Alcántar-Curiel
authors.forename: Ma Dolores
authors.initials: MD
authors.lastname: Jarillo-Quijada
authors.forename: Catalina
authors.initials: C
authors.lastname: Gayosso-Vázquez
authors.forename: María Del Rayo
authors.initials: Mdel R
authors.lastname: Morfin-Otero
authors.forename: Eduardo
authors.initials: E
authors.lastname: Rodríguez-Noriega
authors.forename: José Ignacio
authors.initials: JI
authors.lastname: Santos-Preciado
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects*; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects*; D006801:Humans; D008800:Mexico / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D011112:Polymyxin B / Q000494:pharmacology*; D062606:Tertiary Care Centers
chemical_list: D000900:Anti-Bacterial Agents; D011112:Polymyxin B