Corticoid treatment increases the risk of enterobacter aerogenes infection in intensive care unit
© Current Science Ltd 1998
Published: 1 March 1998
The emergence of multiresistant Enterobacter aerogenes (E.a.) has serious implications in the management of intensive care patients because of increasing risk of nosocomial infection acquisition attributed not only to the severity of the underlying disease, but also to invasive procedures and contaminated life-support equipment. Acquisition of E.a. usually occurs either by colonization with an endogenous strain selected de novo from the patient's own flora (eg broad-spectrum antibiotic follow-up therapy) or by patient-to-patient transmission of strains by the health personnel. E.a. is a difficult-to-treat organism since it is intrinsically resistant to beta-lactam antibiotics and it readily develops multiple drug resistance following the clinical usage of broad-spectrum cephalosporins or carbapenems.
A prospective study comparing risk-factors for E.a. colonization/infection has been conducted in a 12-bed ICU patients (median age, length of stay, mortality rate, mechanical ventilation, antibiotherapy prior to ICU admission, urinary catheter, surgical drain and corticoid therapy). From February 25, 1995 up to May 12, 1995, prescription order of perineal swabs has been undertaken to all patients prior to admission, discharge and on a weekly basis, to rule out the unit specific incidence of E.a. acquisition. 146 patients were included in this study. Out of which, 14 (9.6%) had one or more perineal swabs positive for E.a. and 7 of them had a positive swab the day of the ICU admission.
The E.a. colonization/infection was not significantly associated with patient's median age, mortality rate, antiobiotherapy prior to ICU admission, mechanical ventilation, urinary catheter and surgical drain. A significant association had been noted with corticoid therapy and ICU length of stay (respectively 80 days for E.a. + and 3.0 days for E.a.-), also had been noted that the median SAPS 2 score for colonized/infected patients is superior to the median SAPS 2 score of the ICU patients (43 versus32). Nine patients with E.a. colonization/infection developped infection. Despite appropriate antimicrobial therapy, E.a. colonization was associated with a crude mortality rate of 43%.
These data suggest that corticoid therapy is a risk factor in E.a. colonization/infection in ICU patients and perhaps, indeed, increases the patients mortality rate. Further prospective study are needed to optimize these data and precise the other risk factors. The potential effects of risk factors emphasize the importance of specific measures for infection control in critically ill patients.