title: Surveillance of multidrug-resistant gram-negative bacilli in a neonatal intensive care unit: prominent role of cross transmission.
abstract: BACKGROUND
  Multidrug-resistant gram-negative bacilli (MDRGN) are an important cause of nosocomial infections in neonatal intensive care units (NICUs). We conducted a 1-year prospective surveillance study in an NICU to assess the epidemiology of MDRGN among newborns and the relative importance of acquisition routes.
  
  
  METHODS
  Neonates admitted at the NICU of the Dipartimento Materno-Infantile, University Hospital, Palermo, Italy, from January 7, 2003, to January 6, 2004, were included in the study. Colonization of patients with MDRGN was assessed by cultures of rectal swabs sampled twice a week. Pulsed-field gel electrophoresis was used to determine relatedness among MDRGN isolates. Extended-spectrum beta-lactamases (ESBL) and metallo-beta-lactamases (MBL) production was investigated. The association between risk factors at admission and during the NICU stay was analyzed by multivariate logistic regression analysis.
  
  
  RESULTS
  During the 12-month period January 7, 2003, through January 6, 2004, 1021 rectal swabs were cultured from 210 infants. One hundred sixteen infants (55.2%) were colonized by MDRGN. The monthly incidence of acquisition of MDRGN ranged between 12 and 53 cases per 1000 patient-days. Eighty-four (72.4%) of the 116 patients were cross colonized. Exclusive feeding by formula was significantly associated with cross transmission (RR=1.8, P=.02). Fifty-seven (49.1%) of the 116 infants were colonized by ESBL-producing Enterobacteriaceae. Feeding by formula was significantly associated with colonization by ESBL-producing Enterobacteriaceae (RR=1.6, P=.007), whereas breastfeeding proved to be protective (RR=0.5, P=.001). Ninety-two (43.8%) of the 210 infants received antibiotics during the NICU stay, but exposure to those most frequently administered, ampicillin-sulbactam and gentamicin, was not significantly associated with MDRGN colonization.
  
  
  CONCLUSIONS
  The emerging picture of this study is that spread of MDRGN in an NICU may be the result of diffuse cross transmission and, consequently, of poor infection control procedures.
authors.affiliation: Dipartimento di Igiene e Microbiologia G. D'Alessandro, Università degli Studi, Palermo, Italy. diptigmi@unipa.it
authors.forename: Caterina
authors.initials: C
authors.lastname: Mammina
authors.forename: Paola
authors.initials: P
authors.lastname: Di Carlo
authors.forename: Domenico
authors.initials: D
authors.lastname: Cipolla
authors.forename: Mario
authors.initials: M
authors.lastname: Giuffrè
authors.forename: Alessandra
authors.initials: A
authors.lastname: Casuccio
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Di Gaetano
authors.forename: Maria Rosa Anna
authors.initials: MR
authors.lastname: Plano
authors.forename: Emma
authors.initials: E
authors.lastname: D'Angelo
authors.forename: Lucina
authors.initials: L
authors.lastname: Titone
authors.forename: Giovanni
authors.initials: G
authors.lastname: Corsello
mesh_terms: D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission; D018432:Drug Resistance, Multiple; D016521:Electrophoresis, Gel, Pulsed-Field; D004755:Enterobacteriaceae / Q000145:classification / Q000187:drug effects*; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000635:transmission; D006801:Humans; D007231:Infant, Newborn; D017053:Infection Control; D007363:Intensive Care Units, Neonatal; D007558:Italy / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D011446:Prospective Studies; D018571:Sentinel Surveillance