Antimicrobial drug resistance against Eucalyptus citriodora gum in strains of common microbes of public health concern isolated from food, animals and environment.Author(s): Bhoj Raj Singh
Of the 812 strains of microbes belonging to 27 genera (isolated from food, fish-pond-water, lizards, cow, pigs and mithun) tested against Eucalyptus citriodora gum (EG), 157 (19.3%) strains were detected sensitive. All the strains detected sensitive through disc diffusion method had an MIC 0.25 mg to 5 mg/ ml while those resistant had an MIC of 10 mg to 25 mg/ ml. Significantly (p <0.01) more number of microbial strains isolated from lizards (91.6%) and and mithuns (88.4%) were resistant to EG than strains of cattle (66.7%), pig (65.1%), water (75%) and food origin (65.8%). However, there was no significant difference in sensitivity pattern of strains of lizard and mithun origin (p, 0.33) also among strains of pig, cattle, water and food origin (p, 0.96). Resistant and sensitive strains were distributed among majority of them genera. All the strains of Aeromonas salmonicida ssp. achromogenes (2), A. sobria (2), Citrobacter amalonaticus (11), Edwardsiella hoshiniae (1), Escherichia blattae (3), Hafnea alvei (3), Klebsiella oxytoca (8), Kluyvera cryocrescens (6), Lactobacillus acidophillus (1), Leclercia adecarboxylata, Proteus myxofacience (1), Raoultella terrigena (6), Salmonella enterica ssp. houtenae (3), Salmonella enterica ssp. salamae (11), Serratia fonticola (1), Se. Marcescens (2), Se. odorifera (5), Se. plymuthica (1), Streptococcus milleri (3), Str. alactolyticus (1) and Xenorhhabdus luminiscens (1) were resistant to EG. On the other hand, all strains of Candida albicans (1), Leminorella ghrimontii (1), Micrococcus spp. (2), Providencia heimbachae (1), Staphylococcus aureus (4), Staph. xylosus (2) and Streptocococcus caseolyticus (1) were sensitive to EG. It may be an important question to ponder upon why majority of strains of certain bacteria were resistant to EG and a few strains were sensitive viz., Citrobacter freundii (3 of 74), Erwinia ananas (2 of 12), Escherichia coli (6 of 73), Klebsiella pneumoniae ssp. pneumoniae (4 of 63), Proteus penneri (3 of 16), Pragia fontium (1 of 14), Providencia rettgeri (1 of 5), Salmonella enterica ssp. indica (1 of 45). Similarly, resistance in a few strains of some species comprising mostly sensitive EG strains was also puzzling, such strains were detected among Staph. sciuri (3 of 17), Proteus mirabilis (3 of 8) and Aeromonas caviae (4 of 11). These exceptions may help in future in understanding the factors responsible for resistance or sensitivity to EG. The study has indicated that drug resistance against herbal products is common in strains of some species of microbes while in others it is rare.