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Calcium Potentiated Carbapenem Effectiveness Against Resistant Enterobacter Species
Abiola Isawumi1,2, Molly Kukua Abban1,2, Eunice Ampadubea Ayerakwa1,2
1West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana.
Background:
Antimicrobial resistance (AMR) remains a global health challenge, as bacteria display increasing resistance to last-resort antibiotics such as carbapenems. Enterobacter cloacae are evolving and developing high level of resistance to carbapenems. With increasing AMR, availability of antibiotics for treatment dwindles, hence a need to complement antibiotics to enhance activity or reduce the level of resistance. This study explored the use of calcium ions in attenuating bacterial resistance to carbapenems.
Method:
E. cloacae strains isolated from hospital fomites and air were subjected to antimicrobial susceptibility testing with carbapenem antibiotics (imipenem, meropenem, doripenem and ertapenem) using the disc diffusion (E. coli ATCC 25922 as control). Growth profile, Ca-Adjusted assay and time-kill curve of the strains was determined in the presence and absence of carbapenem antibiotics following a calcium stress assay.
Results:
Growth profile showed that all the E. cloacae strains grew markedly well at 37°C relative to ATCC 25922 and all strains displayed 80% to 100% level of resistance to tested antibiotics. The growth rate of the strains in the presence of the antibiotics was comparable to the growth rate in the absence of carbapenems. Conditional growth stress with calcium ions showed a 50% reduction in the level of resistance with doripenem displaying the lowest level of reduction and ertapenem, the highest.
Discussion:
The study showed that E. cloacae strains displayed high levels of resistance to carbapenems, increasing the possibility of treatment failure. Challenging strains with calcium prior to antibiotic treatment led to a significant reduction in level of resistance, indicating that calcium ions could affect bacterial strains during antibiotic activity leading to reduction in level of resistance.
Conclusion:
Calcium supplement could potentiate carbapenem effectiveness and reduce bacterial AMR.
Insights
Calcium ions significantly reduced carbapenem resistance in *Enterobacter cloacae* strains. This finding suggests calcium supplementation may enhance antibiotic effectiveness against resistant bacteria.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Antimicrobial resistance (AMR) is a growing global health threat, with *Enterobacter cloacae* exhibiting increasing resistance to carbapenem antibiotics.
- The diminishing availability of effective antibiotics necessitates strategies to enhance current treatments or overcome resistance mechanisms.
Purpose of the Study:
- To investigate the potential of calcium ions in mitigating carbapenem resistance in *E. cloacae*.
- To explore calcium's role in potentiating antibiotic activity against resistant bacterial strains.
Main Methods:
- Antimicrobial susceptibility testing of *E. cloacae* strains against carbapenems (imipenem, meropenem, doripenem, ertapenem).
- Growth profiling, calcium stress assays, and time-kill curve analyses were performed in the presence and absence of calcium ions and antibiotics.
Main Results:
- All *E. cloacae* strains demonstrated high-level resistance (80-100%) to tested carbapenems.
- Exposure to calcium ions prior to antibiotic treatment resulted in a notable reduction in resistance levels, up to 50% for ertapenem.
- Calcium ions influenced bacterial response to carbapenems, impacting resistance levels.
Conclusions:
- *Enterobacter cloacae* exhibits substantial resistance to carbapenems, posing a risk for treatment failure.
- Calcium supplementation can significantly attenuate carbapenem resistance in these strains.
- Calcium ions show promise in enhancing carbapenem efficacy and combating bacterial AMR.
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