Nosocomial transmission of highly resistant microorganisms on a spinal cord rehabilitation ward.

Background/objective: To study the mechanism of nosocomial transmission of highly resistant microorganisms (HRMOs).

Design: A prospective observational study.

Setting: A spinal cord ward of a rehabilitation center.

Participants: Patients admitted to the spinal cord rehabilitation ward.

Outcome Measures: HRMOs present in urine and feces. HRMOs, Enterobacteriaceae: (1) that produced an extended-spectrum beta-lactamase (ESBL), (2) that were resistant to carbapenems, (3) that fluoroquinolones and aminoglycosides (for Escherichia coli and Klebsiella species), or other Enterobacteriaceae species that were resistant to 2 of 3 of the following types of antibiotics (fluoroquinolones, aminoglycosides, cotrimoxazole).

Methods: Bacterial growth, identification and sensitivity were tested in urine cultures of 46 patients and faeces cultures of 15 patients. Data were collected on demographic characteristics, underlying diseases, reason and date of admission, room number, method of catheterization (suprapubic, clean intermittent catheterization or indwelling Foley catheter) and antibiotic use.

Results: Nine different HRMOs (7 E. coli, 1 Enterobacter cloacae, and 1 Citrobacter koseri) were isolated in urine samples from 15 patients. E. coli resistant to gentamicin, tetracycline, amoxicillin, cotrimoxazole, and ciprofloxacin were isolated from 8 patients during the study (cluster 1). One strain of multiresistant E coli found before the start of the study was not found during the study period (cluster 2). E coli strains producing an ESBL and resistant to tetracycline, cotrimoxazole, and ciprofloxacin were isolated from urine samples of 3 patients (cluster 3). Ciprofloxacin-resistant E. coli were present in feces of 3 patients (2 in cluster 1). Catheterization was found to be significantly more prevalent in patients with HRMOs. Most of the patients in cluster 1 were treated with antibiotics before the first isolation of the strain.

Conclusions: HRMOs from urine samples were strongly correlated with the use of catheterization. A close correlation was found between prior use of antibiotics and colonization of the urinary tract on the level of the individual patient, which has been rarely described in the literature.