2008—2011 Surveillance of Resistance in Bacteria Isolated from Intensive Care Units in Peking Union Medical College Hospital

  Objective  To investigate the rates of resistance in bacteria obtained from intensive care units (ICU) in Peking Union Medical College Hospital.

  Methods  A total of 3507 non-duplicate clinical isolates from ICU were collected from January 2008 to December 2011. Disc diffusion test (Kirby-Bauer method) was employed to study the antimicrobial resistance. The data were analyzed by WHONET 5.4 software according to Clinical and Laboratory Standards Institute (CLSI) 2011 breakpoints.

  Results  Among these 3507 non-duplicate clinical isolates, gram-negative organisms and gram-positive cocci accounted for 74.7% and 25.3%, respectively. The 10 most common pathogens in ICU were A. baumannii (28.1%), P. aeruginosa (12.8%), S. aureus (10.0%), E. coli (7.8%), K. pneumoniae (7.7%), coagulase-negative staphylococci (7.1%), S. maltophilia (5.2%), E. faecium (4.4%), E. cloacae (2.3%), and E. faecalis (2.3%). Methicillin-resistant Staphylococcus aureus (MRSA) strains and coagulase-negative staphylococci (MRCNS) accounted for 74.9% (262/350) and 83.4% (206/247), respectively. However, 82.6% of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole, while 79.6% of MRCNS strains were susceptible to rifampin. No staphylococcal strain was resistant to vancomycin, teicoplanin, or linezolid. The resistance rates of faecalis to ampicillin (18.2%), nitrofurantoin (5.6%), and fosfomycin (2.7%) were low. The resistant rates of E. faecium and E. faecalis to vancomycin were 9.5% and 1.3%, while to teicoplanin were 7.5% and 1.3%, respectively. Extended spectrum β-lactamases (ESBLs) -producing strains accounted for 60.2% (165/274) and 46.8% (126/269) in E. coli and K. pneumoniae, respectively. The rates of pan-resistant (except minocycline) A. baumannii and P. aeruginosa were 60.4% (596/987) and 5.6% (25/450). The resistance rates of A. baumannii to imipenem and meropenem were 82.8% and 83.8%, respectively. The susceptible rate to minocycline was 58.0%. The resistance rates of P. aeruginosa to imipenem and meropenem were 42.6% and 35.3%, respectively. P. aeruginosa isolates showed the lowest resistant rate (16.8%) to amikacin.

  Conclusion  Carbapenems remain highly active against E. coli and K. pneumoniae. The antibiotic resistance of A. baumanii is increasing, especially those multidrug-resistant and pandrug-resistant strains.