Antibiotic Effects of selected leaf extracts and molecular profile of Klebsiella pneumoniae and Enterobacter bugandensis strain (AdM2)

Abstract

Only healthy surface tissues of healthy animals that are constantly in contact with the environment can easily be colonized by various microbial species, including pathogenic ones. However, these microorganisms are usually the cause of opportunistic infections in animals. Two plants; Vernonia amygdalina (taxonomic ID number 112605) and Ocimum gratissimum (taxonomic ID number 112606) were identified at the Nigerian Federal Research Institute in Ibadan and subsequently concentrated with methanol, water and n-hexane. Twelve pre-slaughter healthy cattle in the same ratio of male to female were selected for this study. Samples from the mouth, skin, nose, vaginal and gastrointestinal tract were collected. Susceptibility patterns for antimicrobial agents were performed using disk-diffusion agar method. All isolates were subjected to bacteriological and molecular identification (PCR and sequencing techniques). Preliminary identification was carried out based on standard bacteriological, microscopic identification, biochemical criteria, while PCR and DNA sequencing techniques were used for molecular identification and analysis. Basic local alignment sequence tools (BLAST) were used to compare retrieved bacterial sequences to a set of previously published strains in the database. The morphological and biochemical profiles of six out of eight normal flora from different sites were Gram-negative. All bacterial cultures were oxidase-positive, including 7 catalase-positive cultures. The majority of isolated bacteria were moderately sensitive to all the extracts tested but resistant to Amoxylin. Noticeable amplification of 16S rRNA genes from Klebsiella pneumoniae strain EMB and Enterobacter bugandensis strain AdM2 was obtained. The amplification of the resistant genes of the two isolates was approximately 1,500 base pairs; however, some of the suspected virulence and antibiotic genes were within this base pair range.