Epidemiology of resistant Enterobacteriaceae in a tertiary hospital

Abstract number: r2011

Andersen  L.P., Pedersen  I.S., Audelin  A., Tvede  M.

Introduction: 

An increase of Enterobacteriaceae (most commonly E. coli and E. cloacae) resistant to cephalosporines and fluoquinolones has been observed within the last years, whereas resistance to aminoglycosides has been stationary. Compared to their use of antibiotic and time of occurance.

Material and methods: 

The incidence of E. coli and E. cloacae resistant to cephalosporins (C), fluquinoloes (F) and aminoglycoside (A) were estimated for each antibiotic and combinations of the three antibiotics in different clinical in the years 2002–2004. The incidences of resistant E. coli and E. cloacae were compared to antibiotic sent from the pharmacy to the departments. To estimate the time of occurance of resistant E. coli and E. cloacae only patients with resistant bacteria in 2003 and 2004 who have not been in this hospital in 2002 were included. To investigate clonal spread of multiresistant bacteria all E. coli and E. cloacae resistant to one or more of the three antibiotics were collected and examined by automatic ribotyping.

Results: 

The incidence of cephlosporin resistance in E. coli and E. cloacae was found in 134 of 4990 (2.7%) patients; in 491 of 4990 (9.8%) patients strains were found resistant to fluquinolones and aminoglycoside resistant strains were found in 76 of 4990 (1.5%) of patients. Combined resistance were found in CA: 0.6%, CF: 1.1%, FA: 0.5% and CAF: 0.3%. No correlation to the use of antibiotic in the departments were found. In about 75% of patients with E. coli or E. cloacae resistant to one or more of the three antibiotics these bacteria were found within the first week after admission at a time where resistance could not yet have been developed at the hospital. The remaining 25% of the patients include those who had a susceptible E. coli or E. cloacae and those in whom these bacteria were not found at the time of admission. Typing of resistant strains revealed that three clones of resistant bacteria occurred in more than one patient. Further typing of strains is needed.

Conclusion: 

The incidence of E. coli and E. cloacae resistant to cephlosporines, fluquinolones and aminoglycosides are still low. The majority of the strains seem to be brought to the hospital when patients are admitted but endemic clones may also occur.