Microorganisms are omnipresent creatures that have both beneficial and harmful features. Earlier, their identification has been a challenging task to the biologists. However, with the advent of scientific developments, key laboratory tests have been devised for their precise characterization based on their morphology and biological properties. In the present context, certain tests yielded results and based on this the identified organisms are as follows. Initially, lactose fermentation was positive. This may indicate that the organism may be Klebsiella pneumonia, Enterobacter pneumoniae, or E.coli(John, 1994). The presence of beta –haemolysis indicates Streptococcus pyogens and Streptococcus agalactiae (John, 1994).The positive result found for catalase and coagulase production may indicate the presence of Staphylococcus aureus bacteria. Oxidase production negative result may indicate that the organism may also be E.coli or Klebsiella apart from Staphylococcus aureus. The appearance of purple coloured cocci in clusters may indicate Staphylococcus or Micrococcus bacteria (John, 1994). The presence of circular shape in the morphology part may indicate that the organism may be Xylophilus ampelinus which is a gram negative aerobic cocci (John, 1994). Similarly, the moderate size, entire margin with yellowish tint pigmentation may further strengthen that the organism is Xylophilus ampelinus(John, 1994). The presence of shiny appearance, smooth texture convex shape nad opaqueness may indicate the possibility of yet another gram negative bacteria Flavimonas oryzihabitans (John, 1994).The above results may indicate that the organisms identified are from both gram negative and gram positive genera of bacteria. These bacteria form a very heterogenous, physiological and morphological group(John, 1994). They may be aerobic or microphilic.The reasons of assigning the organisms under gram negative group could be mainly due to the morphological features like cell shape which is of rod or coccobacilli. Secondly, pigmentation which is yellowish can be emphasized as a key point for identification.
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The catalase is positive for many groups of bacteria cited which is a further indication that the bacteria can be assigned under gram negative genera. The rationale for drawing the above conclusions could be due to the use of culture media for isolation, propagation and differentiation (www.archive.org). For example, brain heart infusion media, tryptose phosphate broth, tryptose blood agar base, heart infusion agar etc types of media have great selection potential to ensure the growth of the expected microorganism (www.archive.org). Next, variation in the susceptibility to certain antibiotics may be considered as another important factor that might play important role in assigning the organisms to specific genera. Gram negative bacteria possess low susceptibility to penicillin and sulfonamide where as they possess high susceptibility to streptomycin, tetracycline and chloramphenicol. Most of these bacteria may also contain 4 rings of flagella in the basal body which is another distinguishing feature.The biochemical characteristics of the organisms have yielded additional insights on their selection criteria. For example, Beta -hemolysis leads to total destruction of erythrocytes encircling the colony (www.textbookofbacteriology.net).This was clearly visible in the plate containing blood agar medium(www.textbookofbacteriology.net). Since, the organisms are beta-hemolytic it can be concluded that they may be of Group A streptococci (www.textbookofbacteriology.net). The organisms which can easily ferment lactose is E.coli. These microorganisms easily survive on media lactose agar medium. Further, the catalase positivity was found on the agar plate enriched with 3% hydrogen peroxide when the cultures have synthesized oxygen and produce bubbles (www.textbookofbacteriology.net). Hence, the presence of two features catalase-positive and oxidase-negative may help in categorizing the bacteria. The bacteria tested positive for coagulase when they were able to produce clots in a glass tube containing plasma (cmgm.stanford.edu). Therefore, with the diagnostic features and available information, the bacteria have been grouped under relevant genera.
- John.J.Holt. Bergeys manual of determinative bacteriology.9th ed.1994.Lippincot.USA
- DIFCO manual of dehydrated culture media and reagents for microbiological and clinical laboratory procedures. Web.
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