Sm. Bhorade et al., The incidence of and clinical variables associated with vancomycin-resistant enterococcal colonization in mechanically ventilated patients, CHEST, 115(4), 1999, pp. 1085-1091
Citations number
37
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Study objectives: (1) To determine in our ICU the incidence of vancomycin-r
esistant enterococcus (VRE) colonization in mechanically ventilated patient
s without a history of VRE infection or colonization; and (2) to determine
the risk factors and outcome variables associated with VRE colonization in
these patients.
Design: A prospective cohort study conducted between January 1996 and March
1998.
Setting Medical and cardiac critical care units in a tertiary care urban un
iversity hospital.
Patients: Mechanically ventilated patients without evidence of pneumonia at
the onset of ventilation.
Interventions: None.
Measurements and results: Patients underwent rectal cultures by standard me
thods on day 1, day 3 or 4, day 6 or 7, and day 14 of intubation to detect
VRE. Thirteen of 83 patients (16%) had rectal cultures positive for VRE (VR
E+) at some point while being mechanically ventilated during their stay in
the ICU. In comparison, approximately 15 of 2,100 medical ICU patients (0.7
%) had clinical VRE, infections as determined by the hospital's infection c
ontrol program during a e-year period. VRE+ patients had a higher incidence
of immunosuppression than patients who had rectal cultures negative for VR
E (VRE-) (9 of 13 [69%] vs 16 of 70 [23%], respectively; p < 0.01) and neut
ropenia (4 of 13 [31%] vs 5 of 70 [7%], respectively; p < 0.01). Hospital l
ength of stay (LOS) was longer in VRE+ patients than in VRE- patients (27 /- 17 days vs 17 +/- 14 days, respectively; p = 0.05), whereas pre-ICU hosp
ital LOS and ICU LOS were similar in both patient groups. Five of 67 patien
ts (7%) were VRE+ on day 1 of intubation, suggesting colonization at a prio
r site of care. Three of 29 patients who had subsequent rectal cultures con
verted to VRE+ while in the ICU. This group had a higher incidence of immun
osuppression and neutropenia, and received more vancomycin compared with th
e patients who remained VRE- (p < 0.01). However there was no significant d
ifference in the use of other broad-spectrum antibiotics (such as antipseud
omonal penicillins, third-generation cephalosporins, quinolones, and clinda
mycin), enteral tube feedings, or sucralfate between the two groups. In add
ition, a topical antibiotic paste (a gentamicin, nystatin, polymixin slurry
) that,vas placed in the oropharynx to prevent bacterial overgrowth was not
found to increase the incidence of VRE colonization in this patient popula
tion.
Conclusions: The incidence of VRE colonization was surprisingly high: 16% i
n mechanically ventilated patients in a hospital in which VRE was not previ
ously known to be endemic. Risk factors for the acquisition of VRE coloniza
tion included immunosuppression, neutropenia, and vancomycin use. Increased
LOSs and hospital costs were seen in VRE+ patients compared to VRE- patien
ts. Whether VRE colonization is a contributor to severe disease that leads
to prolonged hospitalization and increased resource allocation or whether i
t is simply a marker of disease severity cannot be determined from this stu
dy. To the extent that specific antibiotic protocols are used to reduce ant
ibiotic-resistant flora in the ICU, monitoring the incidence of VRE in the
stool specimens of immunocompromised, mechanically ventilated patients can
be a simple and useful tool to assess ne effect of these strategies.