Antibacterial Efficacy of Eucalyptus Globulus and Mentha Piperita against MultidrugResistant 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.