1. Cohorting.

The implementation of patients and/or staff cohorting can improve the effectiveness of a bundle approach to control an outbreak due to MDR-Gram-negative bacteria. Laurent et al. described the failure of contact precautions (CP), isolation room, and active screening cultures (ASC) in controlling an outbreak of ESBL-producing K. pneumoniae. When the infection control measures were reinforced with the introduction of cohorting of colonized/infected patients in a dedicated ICU and total cohorting of nursing care and partial (daily shift only) cohorting of medical staff, the outbreak was controlled. According to the authors, cohorting was probably the most important contributing measure [1].

In a setting where MDR - A. baumannii was epidemic, a first multifaceted approach that included single rooms isolation, use of gloves, gowns and mask for affected patients without identification of carriers with ASC was ineffective in containing the outbreak. In a second phase, a partial ward closure with strict patient physical segregation and barrier nursing along with the use of ASC (three days a week) were introduced and these measures were effective in containing the outbreak [2].


  1. Laurent C, Rodriguez-Villalobos H, Rost F, Strale H, Vincent JL, Deplano A, et al. Intensive care unit outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae controlled by cohorting patients and reinforcing infection control measures. Infect Control Hosp Epidemiol. 2008; 29: 517-524.

  2. Enoch DA, Summers C, Brown NM, Moore L, Gillham MI, Burnstein RM, et al. Investigation and management of an outbreak of multidrug-carbapenem-resistant Acinetobacter baumannii in Cambridge, UK. J Hosp Infect. 2008; 70: 109-118.

Original contribution from:

Maria Adriana Cataldo and Nicola Petrosillo, National Institute for Infectious Diseases “Lazzaro Spallanzani”, Rome, Italy.