--- title: How is Shigellosis Diagnosed? date: 2021-01-04T20:29:00-08:00 author: admin canonical_url: "https://marlerclark.com/foodborne-illnesses/shigella/shigella-diagnosis" section: Resource Library --- [Foodborne Illnesses](/foodborne-illnesses) / [Shigella](https://marlerclark.com/foodborne-illnesses/shigella) / # How is Shigellosis Diagnosed? ### *Shigella* infection is diagnosed through testing of a stool sample. Because the symptoms of a *Shigella* infection are consistent with a fairly large number of potential illnesses, including most foodborne infections, a diagnosis must be confirmed by a laboratory test. First, a stool sample must be obtained from the potentially infected person and then placed on a medium to encourage the growth of bacteria. If and when there is growth, the bacteria are identified, usually by looking at the growth under a microscope. The laboratory can also do special tests to tell which species of *Shigella* the person has and which antibiotics would be best to treat the infection. Antibiotic-sensitivity tests are important because *Shigella* is often resistant to multiple antibiotics. ![](https://s3.us-west-2.amazonaws.com/aboutshigellacom-images/outbreaks/image8.jpeg)More advanced testing and surveillance methods, such as plasmid profiling and chromosomal fingerprinting, can also be used. So-called “genetic fingerprinting” of the bacterial isolate, using pulsed-field gel electrophoresis (PFGE), is a molecular technique that can help to characterize *Shigella* isolates, whether obtained from human or food samples. Taken together, all of these tests can assist public health officials in determining whether cases (confirmed infections) are isolated or associated with common-source outbreaks. There is potential for future creation and use of a rapid stool test for shigellosis diagnosis, but this method is still in testing phases. Efforts to identify outbreaks of foodborne illness—whether caused by *Shigella* or other pathogens—are important to preventing the secondary spread of infection, especially with bacteria as highly communicable as *Shigella*. One major advance in these efforts was the creation of FoodNet. As described by the CDC: > FoodNet is an active surveillance system, meaning that public health officials routinely communicate with more than 650 clinical laboratories serving the surveillance area to identify new cases and conduct periodic audits to ensure that all cases are reported. > FoodNet collects information on laboratory-confirmed cases (defined as isolation for bacteria or identification for parasites of an organism from a clinical specimen) and cases diagnosed using culture-independent methods. Once a case is identified, FoodNet personnel at each site collect information about core variables, enter this information into a database, and transmit data to the CDC. [ Next: Treatment for Shigella Infection › ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-treatment) ### More information about Shigella [February 26, 2020 ###### Mariscos San Juan Restaurant Shigella Outbreak and Litigation - California (2015) According to a Public Health Warning, on Saturday afternoon, October 17, 2015, the Santa Clara County Public Health Department was notified by a local hospital of 5 patients with fever ... ](https://marlerclark.com/news_events/mariscos-san-juan-restaurant-shigella-outbreak-and-litigation-california-2015) [February 11, 2018 ###### Pearl Catering Shigella Outbreak Lawsuits - Oregon (2018) On August 14, 2018 the Oregon Health Authority (OHA) and Yamhill County Health and Human Services received reports of multiple people with gastrointestinal illness days after attending a wedding and ... ](https://marlerclark.com/news_events/pearl-catering-shigella-outbreak-and-litigation-oregon-2018) [November 05, 2014 ###### Salsarita Shigella Outbreak Lawsuit – Arkansas (2014) Salsarita’s Restaurant in the Walmart Home Office Café in Bentonville has reopened following a Shigella outbreak that made 275 sick in nine states. ... ](https://marlerclark.com/news_events/salsarita-shigella-outbreak-lawsuit-arkansas-2014) [March 08, 2010 ###### Subway Restaurant Shigella Outbreak Lawsuits - Illinois (2010) At least 116 people were confirmed ill with Shigella infections traced to a Subway restaurant in Lombard, IL in March of 2010. Marler Clark represented 74 people sickened in this ... ](https://marlerclark.com/news_events/subway-restaurant-shigella-outbreak-chicago) [1. View all ](/news_events/outbreaks?illness=shigella&year=all) ## All Shigella Resources [###### Shigella Food Poisoning ](https://marlerclark.com/foodborne-illnesses/shigella/about-shigella) [###### The Incidence of Shigella Infection ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-incidence) [###### The Prevalence of Shigella in Food and Elsewhere ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-prevalence) [###### How is Shigella Infection Spread? ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-transmission) [###### Symptoms of Shigella Infection ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-symptoms-risks) [###### Complications of Shigella Infection ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-complications) [###### How is Shigellosis Diagnosed? ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-diagnosis) [###### Treatment for Shigella Infection ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-treatment) [###### The Economic Impact of Shigella Infections ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-economic-impact) [###### How to Prevent Shigella Infection ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-prevention) [###### Outbreaks of Shigella Infection ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-outbreaks) [###### Antimicrobial Resistance in Bacteria ](https://marlerclark.com/foodborne-illnesses/shigella/antimicrobial-resistance-in-bacteria-shigella) [###### Shigella References ](https://marlerclark.com/foodborne-illnesses/shigella/shigella-references) ### Other foodborne illnesses [E. coli](https://marlerclark.com/foodborne-illnesses/e-coli) [Salmonella](https://marlerclark.com/foodborne-illnesses/salmonella) [Listeria](https://marlerclark.com/foodborne-illnesses/listeria) [Hepatitis A](https://marlerclark.com/foodborne-illnesses/hepatitis-a) [Reactive Arthritis](https://marlerclark.com/foodborne-illnesses/reactive-arthritis) [Guillain-Barre Syndrome](https://marlerclark.com/foodborne-illnesses/guillain-barre-syndrome) [Irritable Bowel Syndrome](https://marlerclark.com/foodborne-illnesses/irritable-bowel-syndrome) [Norovirus](https://marlerclark.com/foodborne-illnesses/norovirus) [Botulism](https://marlerclark.com/foodborne-illnesses/botulism) [Campylobacter](https://marlerclark.com/foodborne-illnesses/campylobacter) [Cyclospora](https://marlerclark.com/foodborne-illnesses/cyclospora) [Hemolytic Uremic Syndrome](https://marlerclark.com/foodborne-illnesses/hemolytic-uremic-syndrome)