Antibiotic Profiling and Detection of blaimp-1 and blavim-2 in Carbapenem-Resistant Acinetobacter baumannii and Pseudomonas aeruginosa from Selected Tertiary Hospitals in Metro Manila, Philippines
- 1. Department of Medical Technology, University of Santo Tomas, Philippines
- 2. Department of Laboratory Medicine, University of Santo Tomas, Philippines
- 3. Research Center for the Natural and Applied Sciences, University of Santo Tomas, Philippines
Introduction: Acinetobacter baumannii and Pseudomonas aeruginosa are common opportunistic bacteria causing nosocomial infections among hospitalized patients. Aside from being opportunistic, these bacteria, nowadays, are exhibiting resistance to some antibiotics, making antibiotic therapy difficult and challenging. With this, we aimed to determine the presence of some resistance-causing genes such as blaIMP-1 and blaVIM-2, from carbapenem-resistant A.baumannii (CRAB) and carbapenem-resistant P. aeruginosa (CRPA).
Methodology: Purposive sampling was used wherein all CRAB and CRPA isolates were collected from two selected tertiary hospitals in Metro Manila, Philippines. Phenotypic and antibiotic susceptibility testing of the isolates were done using VITEK® 2 Compact. Carbapenem resistance was retestedusing Kirby-Bauer disk diffusion method. For the genotypic identification of the presence of blaIMP-1 and blaVIM-2, the deoxyribonucleic acid (DNA) of the samples was isolated and purified.It was thenamplified through polymerase chain reaction (PCR).Amplicons produced were run through gel electrophoresis for the visualization of bands indicating the presence of blaIMP-1 at 740 bp and blaVIM-2 at 865 bp.
Results: We detected the genes blaIMP-1 and blaVIM-2 in four (58%) and one (14%) CRAB isolates, respectively. One (14%) isolate has both blaIMP-1 and blaVIM-2. While in CRPA isolates, only blaIMP-1was detected in two (67%) isolates. In terms of the antibiotic profiling of the isolates with blaIMP-1 and blaVIM-2, we found that all are resistant against ceftazidime and ciprofloxacin (100%); seven (87.5%) against cefepime, gentamicin, and piperacillin/tazobactam; and one (12.5%) against amikacin. Furthermore, the antibiotic profile of the isolates with no blaIMP-1 and blaVIM-2 are the following: all are resistant against cefepime, ceftazidime, ciprofloxacin, gentamicin, and piperacillin/tazobactam (100%). On the other hand, both blaIMP-1 and blaVIM-2 negative isolates are sensitive to amikacin. All isolates (100%) are sensitive against colistin.
Conclusion: We conclude thatblaIMP-1 is present in CRAB and CRPA, and itis more frequent thanblaVIM-2.This study also concludes the coexistence of multiple metallo-β-lactamase genes in CRAB isolates.