Document text
Principal Investigator: Jose Enrique Pietri
Organization: UNIVERSITY OF SOUTH DAKOTA
Fiscal Year: 2024
Award: $1
Funding agency: National Institute of Allergy and Infectious Diseases
PROJECT SUMMARY
Salmonella enterica serovar Typhimurium is a widespread human enteric pathogen that has a broad range of
animal hosts and environmental reservoirs. Meanwhile, the German cockroach, Blattella germanica, is the most
common pestiferous cockroach species in human environments. B. germanica frequently harbors Salmonella
spp. in nature, serving as both an environmental reservoir and a vector. Transmission of S. Typhimurium by
cockroaches has been previously described as a passive, non-replicative process by which the bacteria are
mechanically transferred from one surface to another. However, our laboratory recently demonstrated that S.
Typhimurium actively colonizes the digestive tract of German cockroaches after being ingested. Colonization of
the cockroach is characterized in part by an initial population bottleneck during which most ingested bacteria are
eliminated. Subsequently, the surviving population of S. Typhimurium undergoes replication and persists in the
cockroach gut, interacting with a highly diverse microbiota. The bacteria that persist are disseminated in the
feces into the environment where they can be ingested by other cockroaches via coprophagy and/or acquired
by a vertebrate host. The central hypothesis of this project is that cockroaches provide a unique environment for
S. Typhimurium to undergo significant evolution as a result of both selection pressure from the host and
interaction with its gut microbiota. Specifically, we hypothesize that evolution in the gut of the cockroach vector
may favor the emergence of novel variants of S. Typhimurium with 1) enhanced ability for vector-borne
transmission, 2) altered potential to colonize other animal hosts, and 3) antimicrobial resistance horizontally
acquired from diverse constituents of the cockroach gut microbiota. We will pursue two specific aims to test our
hypotheses. In specific aim 1, we will use whole genome sequencing to identify the adaptive genotypic changes
that occur in S. Typhimurium after experimental evolution in a laboratory cockroach strain and we will examine
the effects of these changes on fitness in the vector. In specific aim 2, we will determine if S. Typhimurium can
horizontally acquire antimicrobial resistance from commensal bacteria harbored in the gut of field collected
cockroach strains, and we will explore the mechanisms by which this may occur. Together, these studies will
provide novel, naturally relevant insight into how underappreciated insect reservoirs may contribute to evolution
of S. Typhimurium and may implicate insect control as a simple intervention to mitigate pathogen evolution.
Terms: <Affect><Alimentary Canal><Animals><Anti-microbial susceptibility><Antibiotic Agents><Antibiotic Drugs><Antibiotics><Antimicrobial Resistance><Bacteria><Category B pathogen><Category B priority pathogen><Cockroaches><Competence><DNA><Data><Deoxyribonucleic Acid><Dictyoptera><Digestive Tract><Disease><Disorder><Enteral><Enteric><Environment><Evolution><Excretory function><Feces><GI Tract><GI microbiota><Gastrointestinal Tract><Gastrointestinal microbiota><Gastrointestinal tract structure><GeneHomolog><Genes><Genotype><German><German population><Homolog><Homologous Gene><Homologue><Horizontal Gene Transfer><Hour><Human><Infection><Ingestion><Insect Control><Insecta><Insects><Insects Invertebrates><Interphase><Intervention><Intervention Strategies><Laboratories><Lateral Gene Transfer><Mechanics><Miscellaneous Antibiotic><Modern Man><Morbidity><Morbidity - disease rate><NIAID><National Institute of Allergy and Infectious Disease><Nature><Pattern><Phenotype><Plasmids><Population><Process><Proliferating><Property><Public Health><Resistance><Resistance profile><Resistant profile><Route><S enterica serovar Typhimurium><S typhimurium><S. enterica Typhimurium><S. enterica serovar Typhimurium><S. typhimurium><Salmonella><Salmonella enterica Typhimurium><Salmonella enterica serovar Typhimurium><Salmonella typhimurium><Serial Passage><Surface><Testing><Transmission><Variant><Variation><alimentary tract><anti-microbial><anti-microbial resistant><antimicrobial><bacteria pathogen><bacterial pathogen><clinical relevance><clinically relevant><commensal bacteria><commensal bacterial species><digestive canal><enteral pathogen><enteric microbial community><enteric microbiota><enteric pathogen><enteropathogen><entire genome><excretion><fitness><full genome><gastrointestinal microbial flora><genome sequencing><gut commensal><gut community><gut flora><gut microbe community><gut microbes><gut microbial community><gut microbial composition><gut microbial consortia><gut microbial species><gut microbiota><gut microbiotic><gut microflora><improved><ingest><insight><interventional strategy><intestinal flora><intestinal microbes><intestinal microbiota><intestinal microflora><intestinal pathogen><intestinal tract microflora><intestine pathogen><mechanic><mechanical><microbial consortia><microbial flora><microbiota><microflora><mortality><multispecies consortia><novel><pathogen><pathogenic bacteria><pressure><resistance to anti-microbial><resistant><resistant to antimicrobial><stool><transmission process><vector><vector-borne><vectorborne><whole genome>