Date of Completion


Document Type


Degree Name

Grade 12


Pathogens, Bacterial Colonies, Morphological Characteristic, doorknobs, Toilet Facilities


Bacteria are microorganisms that thrive in moist areas; some of which are harmless while others are classified as pathogenic which can cause and spread diseases. Pathogens are microorganisms that are capable of causing and spreading disease, pathogens thrive in moist areas. Restrooms are often subjected to researches for detection of pathogens. This study focused on the doorknobs in the restrooms of Lourdes E. Campos, MD Building of De La Salle Medical and Health Science Institute for detection of pathogens and which floor yielded the most bacterial colonies. Six restroom doorknobs, 3 from each male and female restrooms, were swabbed to collect bacterial samples. These samples were diluted and spread in agar plates to be incubated and let bacteria grow for morphological characterization and colony counting. Out of 72 agar plates containing the samples, only 10 plates have shown bacterial colonies. 9 of which only have 1 colony and the other 1 left has 2 colonies. All restroom doorknobs have shown presence of bacteria with girls restroom having the most number of colonies. In addition, the restroom doorknobs in fourth floor of the building yielded the most bacterial colony among the other floors. Since the colonies that were counted was not able to reach the range of 30-300 colonies, the prevalence of the bacterial colonies accumulated in the samples were noted to be too few to count. The colonies shared multiple morphological characteristics. Common trends among them were having all the samples with dull appearance, nonpigmentation, and an optical property of opaque. Majority of the samples were flat in elevation, circular in shape, small in size, and having entire margins. Based from the morphological characteristics observed from the samples which were compared from different studies similar to it, it has been concluded that most of the obtained bacterial colonies were possibly identified as pathogenic.

First Advisor

Pancho E. Ercilla