Objective To investigate the
antibiotic resistance and resistance
genes of
carbapenem-resistant Enterobacteriaceaes (CRE) isolated from 5
hospitals in Northeast
China.
Methods This study collected 85 CRE isolates during January 2013 to June 2015 from five
hospitals in Northeast
China.
Drug sensitivities of 14
antimicrobial agents were determined by the broth microdilution
method.The
phenotypes of carbapenemases were screened by modified Hodge test and
EDTA test respectively.The
genotypes of carbapenemases and other extended spectrum β-lactamases (ESBL) were detected by
PCR gene amplification and
DNA sequencing method.Using the
PCR result as
gold standard, the performances of other two carbapenemase
detection methods were evaluated.Results Among the 85 CRE
strains collected in this study,
Klebsiella pneumoniae was the most frequently isolated species (61/85,71.8%).The results of
antimicrobial agent sensitivity showed that the 85 CRE
strains had resistance rate of
cephalosporin and β-
lactams/
enzyme inhibitor (
piperacillin-
tazobactam) over 80.0%.The resistance rate of
carbapenem was high, with
ertapenem 100.0% (85/85),
meropenem 65.9% (56/85),
imipenem 71.8% (61/85).There were 36 isolates resistant to both
meropenem and
imipenem.For
fluoroquinolones, the resistance rates of
levofloxacin and
ciprofloxacin were 72.9% (62/85) and 65.9% (56/85), respectively.The resistance rate to
fosfomycin and
amikacin were 65.0% (55/85) and 54.1% (46/85), respectively.The resistance rate of
colistin (21.2%, 18/85) and
tigecycline (20.5%, 17/85) were low.Forty-nine
strains were modified Hodge test positive and 12
strains were
EDTA test positive.By
PCR gene amplification and
DNA sequencing method, 64
strains carried carbapenemase-encoding
genes, of which KPC-2 was the main type (53/85, 62.4%), followed by
IMP-4 (10/85, 11.8%), NDM-5 (7/85, 8.2%) and NDM-6 (1/85, 1.2%).At the same
time, 85 CRE isolates had the ESBL
gene detection and 47 isolates were CTX-M type ESBLs (47/85, 55.3%), with no TEM or SHV type.Conclusions
Klebsiella pneumoniae is the majority of CRE
strains from 5 large
hospitals in Northeastern
China.The CRE
strains are resistant to most of antimicrobials.Most carbapenemases-producing isolates have the KPC-2 type.Nearly half of the carbapenemase-producing
strains also carry ESBL
genes, which makes the resistance mechanisms more complicated.