ABSTRACT
BACKGROUND:- New Delhi metallo-β-lactamase 1 (NDM-1) enzyme leads to multidrug resistance and has been detected from bacteria in many countries. The study was done To detect bacteria carrying blaNDM-1 gene from intensive care unit (ICU) patients and correlate the change with increasing duration of ICU stay. METHODS:- Blood and urine samples were collected from 140 patients thrice- 0-2 days, 3-7 days and 7 days of ICU admission. All bacterial isolates resistant to meropenem were evaluated for Metallo-β-lactamase (MBL) production. blaNDM-1 gene was detected using Real Time PCR from the MBLproducers. RESULT:- Overall, 458 samples (229 each) of blood and urine were collected and 75 gram negative bacteria were isolated. From these, 46.7% (35/75) strains were found to be carbapenem resistant and blaNDM-1 gene was detected in 17.3% (13/75). CONCLUSION:- High prevalence of bacteria carrying blaNDM-1 gene was seen in ICU patients increasing the burden on healthcare.
ABSTRACT
Objective To investigate the transmission of blaNDM-1 gene in carbapenem-resistant Citrobacter freundii. Methods A total of 18 strains of NDM-1-producing C. freundii were collected from the First Affiliated Hospital of Kunming Medical University during the period from June 2012 to October 2014. The isolates were identified and subjected to antimicrobial susceptibility testing with VITEK 2 System. Conjugation experiments, pulsed-field gel electrophoresis (PFGE) and Southern blot hybridization were performed to determine the transferability of plasmids. Results The antibiotic susceptibility results showed that all the NDM-1-producing C. freundii isolates were resistant to penicillins, cephalosporins and carbapenems. All isolates exhibited different level resistance to other antibiotics. Conjugation experiments revealed that the plasmids harboring blaNDM-1 in 13 strains were transformed into E. coli 600, and exhibited carbapenem resistance. PFGE and Southern blot hybridization found that blaNDM-1 was located on a 33.3 kb plasmid in 16 isolates and on 33.3-54.7 kb plasmid in 2 isolates. Conclusions Our findings suggest that plasmids contribute to the horizontal dissemination of blaNDM-1 gene in carbapenemresistant C. freundii.
ABSTRACT
Objective To construct a blaNDM-1gene deletion mutant of Enterobacter cloacae and to analyze its biological characteristics. Methods The blaNDM-1gene deletion mutant was constructed by using Red homologous recombination technology and verified by PCR and RT-qPCR. Antimicrobial susceptibility profiles,growth curves and in vitro competition abilities of the original strain and the blaNDM-1gene deletion mutant were analyzed. Results PCR,DNA sequencing and RT-qPCR showed that the blaNDM-1gene dele-tion mutant was successfully constructed. Antimicrobial susceptibility test showed that the original strain was resistant to imipenem,meropenem and ertapenem, while the blaNDM-1gene deletion mutant was sensitive to all. The original strain and the blaNDM-1gene deletion mutant had similar growth curves in Luria-Bertani liq-uid medium. In vitro competition experiment revealed that the competitive index of them was 0.69. Conclu-sion Red homologous recombination technology can be used to knockout the blaNDM-1gene of Enterobacter cloacae,which is associated with antimicrobial resistance and competitiveness.