How important is patient-to-patient transmission in extended-spectrum beta-lactamase Escherichia coli acquisition.
BACKGROUND
Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli is an emerging pathogen. The causal role of antibiotic selective pressure versus patient-to-patient transmission has not been assessed. The objective of this study was to quantify the amount of patient-to-patient transmission among patients who acquire an ESBL-producing E coli infection using perianal surveillance cultures in an intensive care unit (ICU) population.


METHODS
A prospective cohort of patients admitted between September 1, 2001, and September 1, 2004, to the medical and surgical ICUs at a tertiary care hospital was studied. Patients had perianal cultures on admission, weekly, and upon discharge. Strain typing by pulsed-field gel electrophoresis (PFGE) and epidemiologic criteria were used to quantify the amount of patient-to-patient transmission.


RESULTS
There were 1806 patients admitted to the ICUs. There were 74 patients who had ESBL-producing E coli on admission to the ICU and 23 patients who acquired ESBL-producing E coli. Among these 23 patients, there were 14 PFGE types, and 3 (13%) patient acquisitions were defined as patient-to-patient transmission by similar PFGE type and overlapping time in the hospital.


CONCLUSIONS
Our data suggest that patient-to-patient transmission is not an important cause of the acquisition of ESBL-producing E coli colonization in the ICU setting.
Harris
Anthony D
AD
Department of Epidemiology and Preventive Medicine, University of Maryland, 100 North Greene Street, Baltimore, MD 21201, USA. aharris@epi.umaryland.edu
Kotetishvili
Mamuka
M
Shurland
Simone
S
Johnson
Judy A
JA
Morris
J Glenn
JG
Nemoy
Lucia L
LL
Johnson
J Kristie
JK
D000046:Academic Medical Centers; D000328:Adult; D001003:Anal Canal / Q000382:microbiology; D015142:Baltimore; D003428:Cross Infection / Q000382:microbiology* / Q000635:transmission*; D003470:Culture Media; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology / Q000635:transmission*; D006801:Humans; D007362:Intensive Care Units; D011159:Population Surveillance; D001618:beta-Lactamases / Q000096:biosynthesis*
D003470:Culture Media; D001618:beta-Lactamases