Microbiology Case Study: An Elderly Adult Presenting with Foodborne Illness Related to Shellfish Consumption

Case History

An adult consumed shellfish at a restaurant. Approximately 12 hours after this dinner, the patient experienced the first signs of loose stools, fever, and abdominal cramping. The patient had watery diarrhea for the next three days with 8 bouts a day. The patient did not have a fever after the first day. The patient denied blood in stool or nausea or vomiting. The patient did not have a recent travel history and denied recent antibiotic use. On the 4^th day of symptoms, the patient was seen by their primary care provider. The physical exam was unremarkable except for dehydration. A stool and blood sample were obtained and aggressive hydration was recommended. Blood smear, complete blood panel, and basic metabolic panel resulted in normal. Shigella, Salmonella, Campylobacter, and Shiga-toxin-producing gene were not detected by PCR. The stool sample was set up for culture. Mucoid colonies were noticed after 12 hours on the blood agar plate. MALDI revealed Grimontia hollisae.

Discussion

The genera of Grimontia is one of the new members of the Vibrionaceae family. Grimontia hollisae, previously known as Vibrio hollisae, is currently the only known pathogenic species in the Grimontia genera. Vibrio hollisae was first described and named by Hickman et al. in 1982.¹ However, based on phylogenetic and phenotypical differences V. hollisae was placed into a novel genus, named Grimontia.² It is named after French microbiologist Patrick P. A. Grimont.

G. hollisae are halophilic, gram negative, oxidase-positive, indole-positive, ornithine-negative, and motile by a single polar flagellum.² One of the most important features of G. hollisae is its failure to grow on thiosulfate-citrate-bile salts-sucrose (TCBS) agar, the main phenotypical difference from vibrios.² However, it does grow well on sheep blood agar and marine agar.³ G. hollisae is generally transmitted via shellfish (mostly oysters, mussels, and prawns etc.).² However, it can also be transmitted through infected ocean water, and other foods that are cross-contaminated with the organism.⁴ To date, the person-to-person spread has not been documented.⁴

Diagnosis of G. hollisae can be challenging since it does not grow on Vibrio-selective media (TCBS agar) or on MacConkey.⁵ However, the organism grows well on blood agar plate. Spot oxidase and indole tests may be helpful to rule-in a possible Vibrio or Grimontia species in suspicious cases.⁵ It is important that the stool sample should be collected as soon as possible in patients suspicious for vibrio gastroenteritis.⁵ Cary-Blair medium should be used as transport medium.⁵

The incubation period of G. hollisae is usually 12-24 hours (ranging between 4-96 hours).⁴ It primarily causes moderate to severe gastroenteritis.³ Signs and symptoms of G. hollisae gastroenteritis include fever, abdominal cramping, watery diarrhea, nausea, and vomiting. Although it is mostly self-limited, it may also cause serious conditions such as hypovolemic shock, sepsis, hepatitis, and ileus.^{3, 6-8} Rarely, grossly bloody stool can be seen in severe cases.⁹ Treatment is mostly supportive, oral hydration is preferred over intravenous in tolerating patients.

G. hollisae disease, clinically, is still considered Vibriosis.⁴ Janda et al. showed that among the all other causes of Vibriosis, G. hollisae comprises only 1.2% of the cases.⁵ In 83% of these cases, the organism was isolated from the gastrointestinal system.⁵ Skin and soft tissue specimens were other resources where G. hollisae was isolated.⁵ In the same study, it has been shown that unlike V. cholerea, V. mimicus, and V parahaemolyticus, G. hollisae has never caused an epidemic, a pandemic, or an outbreak.⁵ However, unfortunately, the numbers of vibriosis are in increasing trend due to rising sea surface temperature.¹⁰ Considering the record high temperatures and heat waves in recent years, it is more than a lucky guess that we may see more and more Vibriosis cases in the next years, especially in the summer seasons. As microbiologists and healthcare workers we should be aware of these organisms, their capabilities, their limits, and how to prevent the spread of them.

References

1. Hickman FW, Farmer JJ 3rd, Hollis DG, Fanning GR, Steigerwalt AG, Weaver RE, Brenner DJ. Identification of Vibrio hollisae sp. nov. from patients with diarrhea. J Clin Microbiol. 1982 Mar;15(3):395-401. doi: 10.1128/jcm.15.3.395-401.1982. PMID: 7076812; PMCID: PMC272106.
2. Thompson FL, Hoste B, Vandemeulebroecke K, Swings J. Reclassification of Vibrio hollisae as Grimontia hollisae gen. nov., comb. nov. Int J Syst Evol Microbiol. 2003 Sep;53(Pt 5):1615-1617. doi: 10.1099/ijs.0.02660-0. PMID: 13130058.
3. Hinestrosa F, Madeira RG, Bourbeau PP. Severe gastroenteritis and hypovolemic shock caused by Grimontia (Vibrio) hollisae infection. J Clin Microbiol. 2007 Oct;45(10):3462-3. doi: 10.1128/JCM.01205-07. Epub 2007 Aug 17. PMID: 17704283; PMCID: PMC2045321.
4. https://www.oregon.gov/oha/PH/DiseasesConditions/CommunicableDisease/ReportingCommunicableDisease/ReportingGuidelines/Documents/vibrio.pdf
5. Janda JM, Newton AE, Bopp CA. Vibriosis. Clin Lab Med. 2015 Jun;35(2):273-88. doi: 10.1016/j.cll.2015.02.007. Epub 2015 Apr 9. PMID: 26004642.
6. Edouard S, Daumas A, Branger S, Durand JM, Raoult D, Fournier PE. Grimontia hollisae, a potential agent of gastroenteritis and bacteraemia in the Mediterranean area. Eur J Clin Microbiol Infect Dis. 2009 Jun;28(6):705-7. doi: 10.1007/s10096-008-0678-0. Epub 2008 Dec 17. PMID: 19089475.
7. Gromski MA, Relich RF, Siwiec RM. Grimontia hollisae: A Cause of Severe Ileus in a Seafood-Loving Traveler: 968. American Journal of Gastroenterology: October 2015 – Volume 110 – Issue – p S415-S416
8. Edouard S, Daumas A, Branger S, Durand JM, Raoult D, Fournier PE. Grimontia hollisae, a potential agent of gastroenteritis and bacteraemia in the Mediterranean area. Eur J Clin Microbiol Infect Dis. 2009 Jun;28(6):705-7. doi: 10.1007/s10096-008-0678-0. Epub 2008 Dec 17. PMID: 19089475.
9. Abbott SL, Janda JM. Severe gastroenteritis associated with Vibrio hollisae infection: report of two cases and review. Clin Infect Dis. 1994 Mar;18(3):310-2. doi: 10.1093/clinids/18.3.310. PMID: 8011809.
10. Baker-Austin C, Trinanes J, Gonzalez-Escalona N, Martinez-Urtaza J. Non-Cholera Vibrios: The Microbial Barometer of Climate Change. Trends Microbiol. 2017 Jan;25(1):76-84. doi: 10.1016/j.tim.2016.09.008. Epub 2016 Nov 12. PMID: 27843109.

-Kadir Isidan, MS, MD is a pathology resident at University of Chicago (NorthShore). His academic interests include gastrointestinal pathology and cytopathology.

-Paige M.K. Larkin, PhD, D(ABMM), M(ASCP)^CM is the Director of Molecular Microbiology and Associate Director of Clinical Microbiology at NorthShore University HealthSystem in Evanston, IL. Her interests include mycology, mycobacteriology, point-of-care testing, and molecular diagnostics, especially next generation sequencing.