Abstract
Introduction: β-Lactamase enzymes are one of the most important factors in generating antibiotic resistance
among gram-negative bacteria. Klebsiella pneumoniae is an opportunistic pathogen from the Enterobacteriaceae
family, which plays a major role in the development of hospital infections and people with underlying diseases.
Objectives: This study was aimed to investigate the antimicrobial effect of the essential oil of Teucrium polium on
strains containing antibiotic resistant genes in clinical isolates of Klebsiella pneumoniae in Zahedan.
Materials and Methods: To identify chemical compounds and to investigate the antibacterial effects of T. polium
extract, the leaves of this plant were collected from their natural habitat in May 2018 at full flowering stage.
Extraction was carried out by water distillation method. Antibacterial activity of the extract of this plant and the
least inhibitory concentration of growth on the resistant strains of Klebsiella pneumoniae was performed.
Results: The essential oil yield of T. polium was 75%. Of the 29 compounds identified in the essential oil of the T.
polium, the combination of α-pinene with 12.52%, linalool was the highest in the essential oil of 10.63%. Of the
120 isolates of K. pneumoniae, 52 isolates in the initial screening were positive for ESBL production, of which 39
isolates (32.5%) were positive in the phenotypic confirmatory assay. Around 11 isolates (10.8%) had ampC genes.
Based on the results of polymerase chain reaction (PCR), 76.9%, 12.8%, 30.8%, 28.2%, 25.7% and 56.4% of the
isolates were carriers of FOX, EBC, ACC, DHA, CIT genes and MOX, respectively.
Conclusion: The results of antimicrobial resistance study of isolates showed that the highest resistance to
erythromycin antibiotics (92.5%), cefotaxime (38.4%) and ceftriaxone (35.9%), respectively, while the highest
susceptibility was observed in colistin antibiotics (98.3%), imipenem (90%) and amikacin (88.3%), respectively.
The essential oil of the T. polium had a significant antibacterial effect. Due to the high percentage of high
concentrations of α-pinene and linalool in the essential oil of the T. polium, in such a way that has antibacterial
properties, T. polium can be used to cope with certain pathogenic bacteria.