Background: The occurrence of a MβL-positive isolate in a hospital setting represents a
therapeutic problem, as well as a serious concern for infection control management. The
accurate identification and reporting of MβL-producing P. aeruginosa will aid infection
control practitioners in preventing the spread of these multidrug-resistant isolates.
Objectives: This study aimed to detect and characterize MβL producing P. aeruginosa in
Benha and to evaluate IMP- EDTA CDT as phenotypic screening method for MβL
detection. Methodology: This study was conducted on 100 P.aeruginosa strains isolated
from 220 different clinical specimens collected from patients admitted to Benha
University Hospital and Benha Teaching Hospital. The isolated P. aeruginosa strains
were subjected to antibiotic susceptibility testing by disc diffusion test and MβL detection
both phenotypically by IMP- EDTA CDT and genotypically by multiplex PCR. Results:
Out of 100 P.aeruginosa isolates, 25 strains (25%) were imipenem resistant and 15
strains of them (60%) were carrying genes responsible for MβL production (15% of the
total number of P.aeruginosa). Thirteen strains (13%) were carrying VIM gene while
two strains (2%) were carrying both VIM and SPM genes together. IMP, GIM-1, SIM-1
genes were not detected. None of the imipenem sensitive strains were carrying genes of
MβL production. Nearly all MβL producers were resistant to most antibiotics used while
all strains were sensitive to colistin and polymyxinB. There is very good strength of
agreement between IMP-EDTA CDT and PCR. The sensitivity & specificity of the IMPEDTA
CDT in relation to PCR was 93.3% and 100% respectively. Conclusion: MβL
producers is a serious problem as they are highly resistant to most antibiotics used
making treatment options very limited, VIM gene is the most prevelant one in
comparison with other genes of MβL production and IMP-EDTA CDT is a good and
sensitive test in detecting MβL production.