Researchers Examine Clinical Patterns Associated With ESBL-Producing Isolates

Description of the clinical pictures of patients colonized or infected by ESBL-producing Enterobacteriaceae isolates and admitted to hospital are rather limited in Europe; however, depicting the clinical patterns associated with the carriage of ESBL-producing isolates may allow healthcare providers to identify more rapidly at risk patients. Researchers say this matter is of particular concern because of the growing proportion of ESBL-producing Enterobacteriaceae species isolates worldwide.

Didier Schoevaerdts, of the Department of Geriatric Medicine, Cliniques Universitaires UCL de Mont-Godinne, in Belgium, and colleagues, undertook a descriptive analysis of 114 consecutive patients in whom ESBL-producing Enterobacteriaceae isolates were collected from clinical sample over a 20-month period. Clinical data were collected through retrospective analysis of medical record charts. Microbiological cultures were carried out by standard laboratory methods. The research was published in BMC Infectious Diseases. 

The researchers report that the proportion of ESBL-producing Enterobacteriaceae strains after exclusion of duplicate isolates was 4.5 percent and the incidence rate was 4.3 cases/1,000 patients admitted. Two-thirds of the patients were aged over 65 years and 13 percent (n=15) were living in nursing homes. Sixty-nine patients (61 percent) were considered clinically infected. The number and severity of co-morbidities was high, particularly including diabetes mellitus and chronic renal insufficiency. Other known risk factors for ESBL colonization or infection such as prior antibiotic exposure, urinary catheter or previous hospitalization were often found. The four main diagnostic categories were: urinary tract infections, lower respiratory tract infections, septicaemia and intra-abdominal infections. For hospitalized patients, the median hospital length of stay was 22 days and the average mortality rate during hospitalization was 13 percent (Confidence Interval 95%: 6-20). Escherichia coli, by far, accounted as the most frequent ESBL-producer (77/114; [68%]) while CTX-M-1 group (mostly including CTX-M-15) was the most prevalent ESBL enzyme (n=56).

The researchers add that in this retrospective study, the clinical profiles of patients carrying ESBL-producing Enterobacteriacae is characterized by a high prevalence rate of several major co-morbidities and potential known risk factors. In this group of patients, both the length of hospital stay and overall hospital mortality rates were particularly high. A prospective case-control matched study should be designed and performed in order to control for possible inclusion bias.

Reference: Schoevaerdts D, Bogaerts P, Grimmelprez A, Hubert MD, Delaere B, Jamart J, Swine C and Glupczynski Y. Clinical profiles of patients colonized or infected with extended-spectrum beta-lactamase producing Enterobacteriaceae isolates: a 20 month retrospective study at a Belgian University Hospital. BMC Infectious Diseases 2011, 11:12doi:10.1186/1471-2334-11-12.