Date of Award

Summer 7-6-2022

Document Type


Degree Name

Master of Science (MS)

First Advisor

Dave Bachoon

Second Advisor

Indiren Pillay

Third Advisor

Andrei Barkovskii


Helicobacter pylori is a pathogenic bacterium that infects more than half of the world’s population. The large number of H. pylori infections in Puerto Rico could be related to the waterborne transmission of the pathogen. While the San Juan Bay Estuary (SJBE) system is home to over three million people, water quality studies in this area of Puerto Rico are lacking. The goal of this study is to determine seasonal and yearly (2020-2021) shifts and relationships between the presence of H. pylori and host-specific (human and dog) Bacteroides in streams that flow through the northern coastal zone of Puerto Rico and streams that drain into the SBJE waters using quantitative polymerase chain reaction (qPCR) methods and microbial source tracking (MST) techniques. The 16s rRNA gene fragment of H. pylori was detected in twenty-nine (16.86%) of the 172 water samples collected over the two-year period with higher detection rates in the wet seasons (17.65%) than the dry seasons (16.09%). Microbial source tracking of human- and dog-specific Bacteroides in H. pylori positive samples over the two-year period resulted in equal detection rates (51.72%) of both host sources. Human- and dog-specific Bacteroides were detected in eighty-three (48.26%) and seventy-six (44.19%) of the 172 samples collected, respectively. A total of eleven samples were positive for all three markers (H. pylori, human, dog). Five of these samples were collected during the 2020 sampling event from two sample sites at subbasin Juan Méndez and one sample site from the Blasina, Rio Piedras Norte, and Dona Ana subbasins. The remaining six samples were collected during the 2021 sampling event from two sample sites located at the Dona Ana subbasin, and one sample site from subbasins Juan Méndez, Río Herrera, Blasina, and Río Canovanillas.