N N K, G S
antibiotic sensitivity, antibiotic sensitivity of acid stressed culture., lactobacillus, ph
N N K, G S. Antibiotic Sensitivity Of Acid Stressed Probiotic Lactobacillus Acidophilus Ncdc 291. The Internet Journal of Microbiology. 2010 Volume 9 Number 2.
LAB (Lactic Acid Bacteria)-
A well known proverb “health is wealth” has become the most important subject of concern with the modern world. Healthy lifestyle can be achieved with a nutritious diet, regular exercise etc. When it comes to health and diet, an increasing trend for food containing probiotics is in demand today. Probiotics are usually defined as microbial food supplements, that when administered in adequate amount exert beneficial effects on the host (Khalil
LAB (Lactic Acid Bacteria)-
Antibiotics taken during illness act as a double edged sword killing not only the disease causing microorganisms but also disrupting normal microbial balance of the gut. According to the latest statistics one in five persons taking antibiotics does not take full course of antibiotic therapy because of the side effects associated with it. Common antibiotic side effects include upset stomach, diarrhea, and vaginal infections etc which occur mainly because of the disturbed microbial load or normal bacterial flora of the patient. To overcome this problem supplementary diet including probiotics is a must. For this the antibiotic sensitivity of the probiotic microorganism holds foremost position. Lactobacilli show varied response towards different antibiotics. Increased resistance of the acid stressed culture provides us with a potent probiotic supplement that can withstand high acid conditions in the stomach and colonize the intestine further enhancing the immunity of the patient by discouraging the growth of pathogenic microorganisms. In the present study a well known probiotic i.e.
Material and Methods
Microbial culture of
Initially it was cultured in 12% (v/v) skimmed milk autoclaved at 15 psi for 30 min and incubated for 24 h at 37 °C. Curdling of milk marked the growth of
Effect of pH on growth:
Following the method of Joshi
Antibiotics namely Ampicillin, Erythromycin, Streptomycin, Vancomycin, Penicillin, Chloramphenicol and Tetracycline were chosen in the present study. Ampicillin, Vancomycin, Streptomycin and Penicillin function by inhibiting the cell wall synthesis whereas Chloramphenicol, Erythromycin and Tetracycline inhibit the protein synthesis thereby exerting the bactericidal effect.
Well Diffusion method was followed. Stock solutions of antibiotics were prepared in sterile distilled water. 100 µl of filter sterilized (using syringe filter of pore size 0.22µ) antibiotic solution with final concentration of 1 mg/ml was added into the wells. Control well contained sterile distilled water. Diameter of zone of inhibition was measured with antibiotic zone scale.
Antibiotic sensitivity of acid stressed culture:
As per method of Ehab Essa Kheadr (2006), the culture was sensitized to acidity by repeated subculturing in medium, the pH of which was altered using 1M glacial acetic acid to 4.0. It was subcultured every 24 h for 5 days. Subsequent procedure followed to study the effect of antibiotics is mentioned above.
Effect of pH:
Growth inhibiting effects of Ampicillin, Erythromycin, Streptomycin, Vancomycin, Penicillin, Chloramphenicol and Tetracycline were studied and
Acid stressed culture on the other hand became resistant to all the antibiotics except Chloramphenicol and Tetracycline where a clear zone of 11.0 mm was observed in both (Table 1). 19 mm and 20 mm decrease in zone diameter in case of Chloramphenicol and Tetracycline respectively, indicates that the microorganism became less sensitive towards these antibiotics as well.
Our strain was found to be sensitive to all the antibiotics except Erythromycin. Delgado
On the other hand acid stressed culture of
It can be inferred from the results that acid stressed probiotic Lactic acid bacteria come up as a savior for the individuals who have adverse reactions from these wonder drugs and also by those who suffer from yeast infections. Gut of the individuals harboring acid stressed probiotic microflora can help to improve health of that particular person by resisting the gastrointestinal aggression by disease causing microorganisms. Acid stressed probiotics being resistant to antibiotics can provide probiotic benefit during the course of treatment and alleviate the side effects of these antibiotics.