Molecular Biology & Mechanism of Disease - Report Example

Aim To identify micro-organisms that normally reside in our surroundings especially on the commodities of day-to-day life. Introduction Microbes are indispensible module of our environment. They are associated in a variety of ways with everything we use in our everyday lives (Fratamico, 2005). They are found to be associated with the food that we eat, the clothes we wear/make use of and water we drink/utilize. They may perhaps influence the quality of our lives. Food items may be contaminated during the handling process, surroundings and the sanitary conditions where they are kept (Betts, 2002). On the other hand dish cloth may harbor other micro-organisms as even the tiny food particle serves as a medium for the augmentation of microorganisms and this growth may cause the food decomposition and spoilage. Food and water may also carry pathogenic microbes and as a result transmit disease (Fratamico, 2005). It is therefore essential to understand the microbes linked with the commodities we use in our everyday life. Microbiological assessment of food, water and clothes may present information concerning the quality of processed food, water and clothes indicating the sanitary conditions under which the food was processed, the contamination of water as well as the effectiveness of the method of food preservation (Fratamico, 2005). Protocol Result: Table 1: Cellular morphology, Colony morphology, Selective and Differential Media characteristics and Biochemistry tests Sample Peanut Butter Dam Water Dish Cloth Isolate No Peanut- S Peanut- L Dam -Red Dam –Non Red Dish -weight Dish -Creamy Cellular morphology Gram reaction Gram +ve Gram -ve Gram +ve Gram -ve Gram -ve Gram -ve Cellular morphology Cocci Bacilli Cocci Bacilli Bacilli Bacilli Cell arrangement Strep/Staph-cocci Singular/ Diploid Singular/Diploid Singular/ Diploid Single/Diploid Singular Colony morphology Gross morphology Round Round Round Round Round Round Colony height Raised Flat Plateau Flat Raised Flat Colony margins Smooth Smooth Smooth Smooth Smooth Smooth Colony size Small Large Medium Medium Small Pinpoint Colony pigmentation Creamy Creamy Weight Creamy Red Creamy Colony Characteristic on Selective and Differential Media Blood Agar Non-heamolytic (β) haemolytic Non haemolytic Non-haemolytic Non haemolytic Non haemolytic MacConkeyAgar Non lactose fermenting No growth Non- Lactose fermenting Non- lactose fermenting No growth Lactose fermenting Mannitol Salt Agar No growth No growth No growth No growth Mannitol fermenting No growth Biochemistry Catalase Test Positive Negative Positive Positive Positive Positive Oxidase Test Negative Negative Negative Negative Negative Positive Identification Identification Gram+ve: Streptococci pyogenes Gram-ve:99% Salmonella spp    Serratia marcescens  Aeromonas hydrophila Klebsiella oxytoca Staphylococcus aureus Table 2: Microbact code: Test # Biochemical tests Dam water 1 Peanut Butter 2 Dish Cloth 1 1 Lysine + + + 2 Ornithine + + - 3 H2S - + - 4 Glucose + + + 5 Mannitol + + + 6 Xylose + - - 7 ONPG + - + 8 Indole - - - 9 Urease - - - 10 (VP) - - - 11 Citrate + + + 12 TDA + - - ID Code 6743 7602 4642 Identification 98% S.Liquefaciens 99% Salmonella spp. 90% K.ozaemae 6% S. rubidaea 6% E.coli inactive 2% K.pneumonia Table 3: Antibiotic disc diffusion: Antibiotics Dam water (Red) Dam water (Non-Red) Peanut butter (L) Peanut butter (S) Zone of inhibition (mm) R/S/I Zone of Inhibition (mm) R/S/I Zone of inhibition (mm) R/S/I Zone of inhibition (mm) R/S/I Ampicillin (AM) Zero R 0 R 25 S S S Gentamycin (CN) 26 S 30 S 24 S S S Tetracycline (T) 11 R 23 S 24 S S S Chlormphenicol(C) 32 S Zero R 25 S S S Cepholothine(Cp) Zero R Zero R 30 S S S Clindamycin(Cl) Zero R Zero R Zero R S S Table 4: Antibiotic disc diffusion: Observations & Results: Scientific Drawing: Figure 1- Peanut butter 1: Streptococci pyogenes (Gram +) spherical cells Figure 2- Peanut butter 2 Gram-ve: Salmonella spp. Rod shaped cells  Scientific Drawing Figure 3- Dish cloth 1 Klebsiella Gram negative rods. Observed under Oil Immersion lens Morphology On MacConkeyAgar Figure 4- Dish cloth 2 Staphylococcus aureus Gram Positive spherical cells. Observed under Oil Immersion lens Scientific Drawing Figure 5- Dam water 1 Serratia marcescens Gram negative rods. Observed under Oil Immersion lens Figure 6- Dam water 2 Aeromonas hydrophila Gram negative rods. Observed under Oil Immersion lens Discussion Smears obtained from various samples were observed under microscope after performing the basic Gram Staining, differential staining to segregate two major groups of micro-organisms (Brett, 2002). This reaction is based on the bacterial cell wall structure. The Gram-positive bacteria retains the purple coloured crystal violet stain as they possess thick peptidoglycan layer in their cell wall, on the other hand, Gram-negative bacteria possess thin peptidoglycan layer and cannot retain the crystal violet stain and therefore they take up the pink coloured Safranin, the counter stain. These Gram-negative organisms also possess high lipid concentration in their cell wall and therefore show much resistance towards most of the drugs (Downes, 2001). Different samples collected, were observed under microscope after performing Gram staining, based on morphology and Gram reactions they were categorized as Gram- positive E.g. Streptococci pyogenes and Staphylococcus aureus and Gram negative e.g. Salmonella spp,  Serratia marcescens, Aeromonas hydrophila, Klebsiella oxytoca respectively. It is difficult to characterize bacteria merely on the basis of Gram reaction as in the present case, four out of six isolates were G-ve and only two isolates were G +ve. To further differentiate, it is essential to understand the colony characteristics of the organism which is performed with the help of various differential media, growth patterns and characteristics as these are imperative in defining the characteristics of the isolates to identify them to the species level. Further, biochemical tests were performed to identify the organisms based on the biochemical characteristics they display (Downes, 2001; Fratamico, 2005). Later, antibiotic sensitivity was used to test the sensitivity of the isolates for various antibiotics. Greater the zone of inhibition around the antibiotic display sensitivity of the isolates towards the antibiotic, whereas if the zone of inhibition is less then it depicts the resistance towards that antibiotic (Downes, 2001; Fratamico, 2005). In the present study, isolate obtained from the sample collected from Dam water (Red) shows resistance towards many antibiotics demonstrating the disease causing ability of the isolate. This isolate was identified as Serratia marcescen. It is capable of causing infections of urinary tract, respiratory tract and wounds, eye infections like conjunctivitis, keratitis, endophthalmitis, lachrymal duct infection, endocarditis, osteomyelitis, pneumonia and meningitis. They show high level of resistance to various antibiotics especially to ampicillin, macrolides and first generation cephalosporins. It is therefore essential to do microbiological examination of water before consumption (Hejazi, 1997). Food borne pathogens are the foremost basis of ill health and fatality in many developing countries as it results in gastrointestinal diseases, pathogenic progression is accountable for resistance to antibiotics (Fratamico, 2005). One of the isolates obtained from peanut butter was Streptococcus pyogenes capable of causing suppurative infections. The pathogen is of chief apprehension in occasional cases it results in swift progression of disease. It is responsible for infections like pharyngitis, scarlet fever, impetigo, cellulites, also invasive toxigenic infections cause necrotizing fasciitis, myositis, rheumatic fever and acute glomerulonephritis (Schaechter , 1998; Tomasz, 2000). Salmonella one of the isolates obtained from the peanut butter is responsible for causing diarrhea, nausea, vomiting, abdominal pain, headache, fever (Schaechter, 1998). Aeromonas hydrophilia found in freshwater environment and is obtained as one of the isolates from the sample collected from Dam water is responsible for cellulites which can be fatal under untreated conditions (Schaechter, 1998). The organism shows resistance towards various antibiotics. In the isolates obtained from the dish cloth, the organisms identified were Klebsiella oxytoca and Staphylococcus aureus. These isolates are known to be responsible for various other dreaded diseases. Klebsiella oxytoca is known to cause colitis and sepsis; while Staphylococcus aureus possesses carotenoid pigment staphyloxanthin which is responsible for its virulence characteristic and thereby cause skin infections encompassing folliculitis, carbuncles, scalded skin syndrome (sss), gradually affecting soft tissues, endovascular tissues and bones (Schaechter, 1998). It is therefore essential to combat these micro-organisms to prevent the occurrence of these diseases. Conclusion The isolates obtained from the commodities which are used in day-to-day life indicated that there is a soaring requirement to microbiologically examine the consumables especially the food and water which are potent carriers of infectious micro-organisms. In the present study, G +ve Streptococci pyogenes and Staphylococcus aureus and Gram negative Salmonella spp,  Serratia marcescens, Aeromonas hydrophila, Klebsiella oxytoca were isolated. Considering the impending role of these micro-organisms in the disease causing abilities and virulence they possess it is essential to consider the microbiological examination of consumables as a necessity. Examinations carried out in the present study lay the foundation of further research to eliminate microbial population from food and water. It is also essential to maintain appropriate hygiene and sanitary conditions to avoid infectious microbial populace on material like dish cloth that indirectly affects the quality of food that is being consumed. The present study paves the way to have a close look on the consequences that may be witnessed if ignorance regarding hygiene take a toll. References Betts, RF., Chapman, SW., Penn, RL. 2002. A Practical Approach to Infectious Diseases. 5th Edition, Lippincott Williams & Wilkins Downes, FP., Ito, K. 2001. Compendium of Methods for the Microbiological Examinations of Foods, Fourth Edition, American Public Health Association. Fratamico, PM., Bhunia, AK., Smith, JL. 2005. Foodborne Pathogens: Microbiology and Molecular Biology, Caister Academic Press. Hejazi A, Falkiner FR. 1997. "Serratia marcescens". J Med Microbiol, 46 (11), 903–12. Lindsay, J. 2008. Staphylococcus: Molecular Genetics, Caister Academic Press. Schaechter, M., Engleberg, NC., Eisenstein, BI., Medoff, G. 1998. Mechanism of Microbial Diseases. 3rd Edition. Lippincott Williams & Wilkins. Tomasz, A. 2000. Streptococcus pneumoniae: Molecular Biology & Mechanism of Disease. 1st Edition, Mary Ann Liebert. Read More