Samples as a Means of Observation of Microorganisms in the Immediate Environment

Purpose

In this experiment five different samples from the environment are collected and cultivated to examine the microorganisms present in the immediate environment. The samples taken were from a door handle, foot, the inside of an incubator, a forehead, and a sink handle. The samples taken from the body were incubated at ~37 Celsius where the ones in the environment were incubated at room temperature.

Procedure:

Five swabs are taken from different portions of the body and the environment and quad streaked onto individual plates. These plates are incubated for roughly 48 hours, at either 37 or 25 degrees Celsius depending on if the sample was taken from the body.

Results:

Door handle Sample Foot Sample Forehead Sample

Incubator Sample Sink Handle Sample

Conclusions:

It seems that the organisms present in the area were of very similar nature. For the two samples taken from the body, only two types of bacteria were present, but both samples shared the same type of characteristics. The foot and forehead sample both had two types of colonies, one forming larger white colonies, and the other smaller, more dense ones. The plates made from the environment had little growth, which could be due to the samples being taken from metal, which often has the potential to kill certain microorganisms, which is most likely the result for the door handle sample where no growth was seen. The little culture that was grown from the incubator and the sink handle both showed the same kind of large white colony growth that appeared on the body samples.

Colony Morphology

Purpose:

The characteristics and distinctions of different microbial colonies will be examined through incubation of a multitude of organisms. Color, shape, texture and other physical observations will be made to identify five different microorganisms cultured.

Procedure:

Five different microorganism samples are cultured on their own individual petri dish. These organisms are Micrococcus luteus, Kiebsiella pneumonia, Serratia marcescens, Bacillus subtilis, and finally Pseudomonas aeruginosa. The petri dishes are incubated at 37 degrees Celsius except form marcescens, which is incubated at 25 degrees. The samples are then examined for different physical characteristics in around 48 hours.

Results:

Micrococcus Bacillus Klebsiella Pseudomonas Serratia

Luteus subtilis pneumonia aeruginosa marcescens

Conclusion:

Five different samples contained enough morphological distinction to be able to separate and classify them by their physical traits. Micrococcus luteus was a yellow color with small, dense colonies throughout the sample. Bacillus subtilis created a thin layer of opaque, white colonies with a large size. Kiebsiella pneumonia created a thick glossy looking colonies, but with small diameters. Pseudomonas aeruginosa created a sample similar to luteus, wide, opaque white film, but had a slightly different, more yellowish pigment to the sample., Serratia marcescens was a reddish color, with colonies of a small radius, yet had a fairly high elevation on the particular colonies.

Growth Patterns on Slants

Purpose:

The morphology of five different microorganism cultures will be examined through their cultivation on slant mediums. The different physical differences are compared after an inoculation of roughly 48 hours.

Procedure:

Five different microorganism samples are transferred via inoculation loop onto their own individual slant medium. All of these samples are inoculated at roughly 35 degrees Celsius. After 48 hours the samples are examined for morphological differences. The organisms transferred onto individual slants are Micrococcus luteus, Kiebsiella pneumonia, Serratia marcescens, Bacillus subtilis, and Pseudomonas aeruginosa.

Results:

P. aeruginosa B. subtilis M. luteus S. Marcescens K. pneumonia

Conclusion:

All of the samples had very similar morphology with this type of medium, excluding how vigorous the growth was, or the amount of growth going deep within the medium. Three of the samples, aeruginosa, luteus, and marcescens seemed to have only grown on the surface of the slant and did not truly grow deeper than the surface layer. The other two samples grew more deeply into the slant medium, rather than just on the surface. This is probably depending on whether the organism can tolerate an anaerobic environment.

Growth Patterns in Broths

Purpose:

Five different types of microorganisms are cultivated in a broth medium to identify different growth characteristics. With these growth characteristics the microorganisms can better be classified.

Procedure:

Five different microorganisms, Micrococcus luteus, Kiebsiella pneumonia, Serratia marcescens, Bacillus subtilis, and Pseudomonas aeruginosa, are transferred to their own individual broth medium via an inoculation loop. These samples are then incubated at 35 degrees Celsius for roughly 24 to 48 hours. After this time the samples are examined for morphological differences.

Results:

M. luteus K. pneumonia P. aeruginosa B. subtilis S. marcescens

Conclusion:

For many of the samples no growth was observed. There was only two samples, pneumonia and aeruginosa, that showed significant growth in the form of cloudiness. S. marcescens also showed slight cloudiness but very insignificant. It seems that this type of medium is not necessarily idea for the growth of microorganisms like some of the other media used. These samples all showed little growth and almost no variety, making it a poor method of separating organisms morphologically.

Fluid Thioglycollate Medium

Four different microorganisms are cultivated in a thioglycollated broth with two layers to identify whether the organisms grow best in an aerobic or anaerobic environments. The samples are incubated all at 35 degrees Celsius and when growth occurs the layers are checked for signs of growth.

Procedure:

Four different organisms, M. luteus, P. aeruginosa, C. sporogenes, and S. aureus, are transferred into their own individual thioglycollate broth via a sterilized inoculation loop. These samples are then all incubated at 35 degrees Celsius for 24 to 48 hours. After this time period, the samples are examined to determine which layers of the thioglycollate broth has growth occurring.

Results:

S. aureus M. luteus P. aeruginosa C. sporogenes

Conclusion:

The thioglycollate growth helps to identify the oxygen requirements of the organisms that are being sampled. The microorganism’s aero tolerance category is the following:

S. aureus- facultative anaerobe, M. luteus- facultative anaerobe, P. aeruginosa- strict anaerobe, C. sporogenes- aero tolerant anaerobe.

Overall this type of medium exposes the oxygen requirement of the organisms by varying the oxygen concentration in different layers, and helps to show this by examining the growth in each particular layer.