This presentation explores the interplay between climate change and the increasing incidence of Vibrio vulnificus infections in 2023. It delves into the effects of rising ocean temperatures, altered marine ecosystems, sea level rise, changes in salinity, and extended warm seasons on the prevalence of Vibrio vulnificus. This informative presentation sheds light on the environmental factors contributing to the emergence of this health risk.

1. Dr. Sourav
MD (Resident)
Phase-A, Year-2
Dept of Microbiology and Immunology
BSMMU

3. History
• The pathogen was first isolated in 1976 from a series of blood
culture samples submitted to the CDC in Atlanta
• In 2005, health officials clearly identified strains of V. vulnificus
infections among evacuees from New Orleans due to the
flooding there caused by Hurricane Katrina
• In 2015, in Florida, eight cases of V. vulnificus infection with
two resulting in death were reported

4. • By October 18, 2022, four deaths and 29 illnesses had been
recorded since landfall of the hurricane in late September
• This year, 2023 already 13 cases of death was recorded in USA
coastal area in last few months
• US Centers for Disease Control and Prevention issued a
“national health alert” on 1st September for people infected with
the flesh-eating bacteria Vibrio vulnificus.

5. Objectives
Structure
Virulence factors
Mode of transmission
Sign-symptoms
Pathogenesis
Lab diagnosis
Treatment and prevention

6. Introduction
• Vibrio naturally live in coastal waters, including salt water and brackish
water
• Can survive in water temperatures between 9℃ – 31℃
• About 150–200 V. vulnificus infections are reported to CDC each year
• About one in five people with this infection die—sometimes within 1–2
days of becoming ill

7. Original locations of
the 709 confirmed
non-foodborne V.
vulnificus infections
reported to the
“Cholera and Other
Vibrio Illness
Surveillance (COVIS)”
database between
2007 and 2018 within
200 km of the east
USA coastline (blue
shading)

8. • Overall annual costs associated with this pathogen are
estimated at US$ 320 million, making it the most expensive
marine pathogen in the USA to treat
• The presence of V. vulnificus does not affect the taste or odor
of contaminated seafood, making detection challenging

9. Impact of climate change
• Greenhouse gas emissions from human activity are changing our
climate
• The global mean temperature has risen 1-2°C since the pre-
industrial period
• These associations with climate have led to Vibrio species being
collectively recognized as a “microbial barometer of climate
change”

10. • Despite being endemic to subtropical
regions Vibrio spp. infections have
recently emerged at higher latitudes
• The bacteria thrive in warmer waters
(>18°C) especially during the summer
months (April to October) and in low-salt
marine environments
Impact of climate change (Contd…)

11. Source: Emerging
infectious disease
2008, CDC
• During July–August 2023, the United States has experienced
above-average coastal sea surface temperatures and
widespread heat waves

12. • During the same period, several East Coast states, including
Connecticut, New York, and North Carolina, have reported severe
and fatal V. vulnificus infections
• Majority infections acquired after an open wound was exposed to
coastal waters in those states
Impact of climate change (Contd…)

13. • Gram-negative, curved, rod-
shaped bacteria
• Typically about 1-3 μm in
length and 0.5 μm in width
• Motile with single polar
flagella
• Part of bacterial flora of
marine environment
Structure
KINGDOM: Bacteria
PHYLUM: Proteobacteria
ORDER: Vibrionales
FAMILY: Vibrionaceae
GENUS: Vibrio
SPECIES: Vibrio vulnificus
Taxonomy

14. Biotypes
• There are three established biotypes of V. vulnificus
• Biotype 1
Most commonly associated with severe infections in humans
They are responsible for the majority of clinical cases and
can cause wound infections, septicemia, and gastroenteritis,
particularly in individuals with underlying health conditions or
compromised immune systems

15. • Biotype 2 and 3
Primarily associated with infections in eels and other fish
species
They are less commonly associated with human infections
and are considered less virulent for humans compared to
Biotype 1 strains

16. Virulence factors
Source: Janina Ruffini

17. High risk group
• People with liver disorders eg. cirrhosis, HCC, Chronic hepatitis etc
• Hemochromatosis
• DM
• HIV/AIDS
• Cancer
• Taking prescribed medications to lower stomach acid levels

18. Mode of transmission

19. Sign-symptoms

20. Characteristics of V. vulnificus infections
• Invasiveness
Invasion of epithelial cells
Destruction of epithelium
• Septic shock and death
Evasion of innate immune response
Induction of overwhelming immune response
• Formation of skin lesion
Induction of inflammation
Tissue damage by bacterial products

21. Resulting illness
Three rapid distinct clinical syndrome-
• Rapid onset of fulminating septicemia- Fever and chills with
vomiting, nausea and diarrhea. Painful skin lesions may develop
• Rapidly progressing cellulitis- results when skin lacerations or
abrasions come in direct contact with seawater containing V.
vulnificus. Additionally, wound infections can occur during acute,
penetrating marine injuries
• Gastroenteritis- Associated with ingestion. Death is rare.

22. Wound infections from V. vulnificus
• Infections usually begin with redness, swelling
and intense pain around the infected site
• Often fluid-filled blisters develop and progress
to tissue necrosis. Can resemble gas gangrene
• About 50% of patients with V. vulnificus
wounds will require surgery or amputation
Primary septicemic skin
lesion in V. vulnificus

23. • Most infections are acute but with no
long- term consequences
• In patients who develop septic shock
from infection with V. vulnificus, the
mortality rate is 50%
• In rare instances, skin infection can
result in necrotizing fasciitis

24. Diagnosis
Consider V. vulnificus for coastal water-exposed wounds, especially in
high-risk patients
If V. vulnificus infection is suspected,
Obtain wound or hemorrhagic bullae cultures and send to local
public health lab
Blood cultures recommended if febrile, with hemorrhagic bullae, or
signs of sepsis
Ask about relevant exposures: coastal water contact with open
wound, scratches, or contact with raw seafood

25. Specimen: -Wound swabs or
-Other relevant sites (e.g., blood, tissue)
Gram stain:
Gram-negative bacteria
which appears pink / red
under a microscope

26. Culture:
 Media: Selective media like TCBS
 Incubation: 35-37ºC for 18-24
hours
 Need NaCl for growth
 Colony morphology: typically
greenish, slightly convex, and
may have a slightly fruity odor
Colonies of Vibrio vulnificus,
strain VV100, cultivated on TCBS
cholera agar during 24 h at 37°.

27. On blood agar plate
 Beta-hemolysis (complete clearing
of blood cells around the colony)
is found

28. Biochemical tests
V. Vulnificus
Oxidase +
Lactose +
Sucrose V
Lysine decarboxylase +
Arginine dihydrolase -
Ornithine
decarboxylase
V
Growth in 0% NaCl -
Growth in 1-2% NaCl +
PCR
Rt-qPCR
Molecular diagnosis

29. Clinical Management
• Vibrio vulnificus wound infections have a mortality rate around
25%
• People in whom the infection worsens into sepsis, typically
following ingestion, the mortality rate rises to 50%
• Majority of these people die within the first 48 hours of infection
• So prompt initiation of treatment is important

30. • Early antibiotic therapy and early surgical intervention
improve survival
• Do not wait for consultation with an infectious disease
specialist or laboratory confirmation of V. vulnificus infection
to initiate treatment

31. Wound care
• Careful attention to the wound site
• Necrotic tissue should be debrided
• Severe cases might require aggressive debridement, fasciotomy,
or amputation of the infected limb

33. Antibiotic therapy
• Preffered: Doxycycline + 3rd gen
cephalosporins (Inj. Ceftazidime)
• Alternative regimens: 3rd gen
cephalosporine + fluroquinolone

34. Prevention of infection
• Eat oysters that have been cooked properly
• Eat oysters that have been post-harvest treated
• Do not let raw seafood touch cooked seafood
• If eating raw oysters, ask the origin of the oysters
• Avoid eating raw oysters
• Do not swim/wade in seawater with open sores or wounds

35. Conclusion
• Serious illness or death can occur in persons with preexisting
liver disease or compromised immune systems
• Has the highest case fatality rate among all foodborne
pathogens
• Infection of open wounds can be serious
• Prevention is the key to mitigate this infections

36. Questions
How do you think climate change is impacting the prevalence
of Vibrio vulnificus infections in coastal regions?
What are the virulence factors of V. vulnificus?
How to prevent this infection?

37. Thank You