Abstract：Objectives To investigate the blaNDM-1 gene of 30 CRE isolates recovered from April 2013 to March 2014 in our hospital, and the clinical characteristics of patients with CRE infections, as well as its relationship to antibiotic resistance. Methods Identification and drug resistance were tested by the BD Phoenix-100 system. Modified Hodge Test was used for the screening of carbapenemase. EDTA-synergy test was used for the detection of metallo-β-lactamases. PCR was performed for blaNDM-1 and the positive products were sequenced and analyzed with BLAST. Results (1) The distribution of isolates: the 30 CRE isolates from the clinical specimens of patients in our hospital between April 2013 and March 2014, including 16 isolates of Klebsiella pneumoniae (53.3%), 12 isolates of Enterobacter cloacae (40%), one isolate of Citrobacter brinell, and one isolate of Citrobacter freundii. These isolates were mainly collected from the intensive care unit (15/30, 50.0%), and neurological intensive care unit (8/30, 26.7%). Most of them were isolated from the sputum sample (12/30, 66.7%), followed by the urine (5/30, 16.7%), the blood (4/30, 13.3%), and the drainage fluid (1/30, 3.3%). The five blaNDM-1 gene carrying isolates were recovered from four patients with an average age of 73, and the average hospitalization time lasted 10 months; among these, three isolates were collected from urine, and two from sputum; two patients survived and two patients died. (2) The results of the drug resistance test: the resistance rates of 30 CRE to imipenem and meropenem were 100% and 86.7%, respectively; the resistance rates to the other β-lactam antibiotics were 100%. The resistance rates to chloramphenicol, gentamicin, levofloxacin, and ciprofloxacin were among 66.7%~93.3%. All of them were most sensitive to colistin and tigecycline, the sensitive rates were 100%; followed by trimethoprim/sulfamethoxazole and amikacin, the sensitive rates were 66.7% and 46.7%. All of the five NDM-1-producing isolates were sensitive to colistin and tigecycline; three isolates were sensitive to trimethoprim/sulfamethoxazole, and two isolates were sensitive to amikacin. All of the five NDM-1-producing isolates were resistant to β-lactam antibiotics, quinolones, and chloramphenicols. Conclusion 30 CRE isolates in our hospital were mainly collected from ICU and NICU, and were highly resistant to multiple antibiotics. The NDM-1-producing isolates were mainly recovered from long-term hospitalized senile patients with a high mortality rate. Therefore, we should investigate the risk factors of infections, and take effective measures to control infections.
