Antibacterial Efficacy of Eucalyptus Globulus and Mentha Piperita against Multidrug-Resistant Bacteria Associated with Pneumonia in Kaduna

Abstract

Background: On the scale of global infectious disease incidence, pneumonia ranked as one of the major leading infectious diseases with a debilitating impact and high death rate among children below 5 years in Nigeria, with the highest deaths among children less than 2 years, and northern Nigeria is considered a hotspot. Since below 30% of infected children receive prompt antibiotic treatment and the growing antimicrobial resistance profile of associated bacteria, pneumonia accounts for approximately 16–19% annual deaths, resulting in an estimated 162,000 annual deaths at 18 deaths per hour in Nigeria, and is triggered by low vaccination coverage, indoor air pollution and malnutrition.

Aim: This study was designed to determine the antibacterial efficacy of Eucalyptus globulus and Mentha piperita against multidrug-resistant bacteria isolated from pneumonia patients in Kaduna, Nigeria for alternative and better treatment option.

Methods: A total of 15 multidrug-resistant (isolates with MARI ≥0.5) bacterial isolates, 3 from each bacterium (Ps. aeruginosa, K. pneumoniae, Streptococcus pneumoniae, E. coli, and S. aureus) from pneumonia patients attending Barau Dikko Teaching Hospital, Kaduna, were collected from our previous study on the prevalence of multidrug-resistant bacterial pneumonia in Kaduna, Nigeria. The antimicrobial activity of Mentha piperita and Eucalyptus globulus ethanolic extracts on multidrug-resistant isolates was evaluated using the Kirby-Bauer disc diffusion method, while Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays were determined using the CLSI method.

Results: Overall assessment of the susceptibility profile of the selected isolates that were 100% MDR and MARI ≥ 0.5 showed that 80% of the isolates were resistant to tetracycline, amoxicillin and chloramphenicol, 73.3% were resistant to cefotaxime, 60% were resistant to cotrimoxazole and amoxicillin-clavulanic acid and 53.3% resistant to imipenem while most of the isolates were still susceptible to ciprofloxacin (73.3%) and azithromycin (53.3%).  Mentha piperita extract exhibited significant antimicrobial activity against all tested multidrug-resistant bacteria, with MIC values ranging from 250 mg/ml to 450 mg/ml, while Eucalyptus globulus extract also showed activity, but with higher MIC values. The combination of Mentha piperita and Eucalyptus globulus extracts showed enhanced antimicrobial activity with zones of inhibition higher than when tested alone, and as compared with the control.

Conclusion: The study demonstrates the potential of Mentha piperita and Eucalyptus globulus extracts as natural antimicrobial agents against pneumonia-causing bacteria. The combination of these extracts may offer a promising approach for the treatment of pneumonia.

Keywords: Mentha piperita, Eucalyptus globulus, bacteria, pneumonia, multidrug resistance