Foodborne Bacterial Infections ◾ 365
Vibrio vulnificus 43
Vib. vulnificus is often responsible for serious septicemia and would cause infection. It is a gramnegative, lactose-positive, salicin-positive, halophilic bacteria found in the estuarine environment
in coastal waters globally. It is considered a highly lethal pathogen because of its ability to invade
the bloodstream. Vib. vulnificus has been associated with fulminating septicemia from the consumption of contaminated seafood as well as progressive cellulitis and tissue necrosis, resulting
from wound infection. Following consumption of contaminated seafood, in many cases raw oysters or clams, the cells penetrate the intestinal wall and produce primary septicemia in 20–40
hours. Vib. vulnificus produces several virulence factors, including the ability to survive stomach
acid, capsular polysaccharide, lipopolysaccharide, cytotoxins, pili, and flagellum, which allow the
bacterium to enter into the bloodstream to cause septicemia. Symptoms are chills, fever, and
prostration with occasional vomiting and diarrhea. The fulminating septicemia sets up rapidly,
which can be fatal in many cases. The infection and fatality rate is very high (40%–60%) among
people with liver and gastric diseases and immunodeficiencies. This organism can cause severe
wound infection in individuals with preexisting cuts, skin lesions, and punctures in the skin during swimming or during handling of seafoods (especially the fisherman). In severe cases, tissue
necrosis and secondary sepsis may develop; thus, surgical debridement or amputation may be
required. The fatality rate for wound infection is 20%–30% and is related to underlying conditions. Control measures should include methods discussed for Vib. parahaemolyticus. Susceptible
individuals should avoid consumption of raw seafoods, such as oysters.
Brucellosis 44
Human brucellosis is a zoonotic infection caused by Brucella spp., namely, Brucella abortus, Bru.
suis, and Bru. melitensis. They are Gram-negative, nonmotile, nonsporeforming, aerobic small rods
pathogenic to animals and humans. In infected animals, the organisms are located in the uterus
of pregnant animals and in the mammary glands of lactating females. Thus, the pathogens can
be excreted in milk. People working with animals can become infected with Brucella spp. Also,
people working with meat can be infected. Consumption of raw milk and some products made
from raw milk (such as some imported cheese) have been implicated in foodborne brucellosis. The
cells survive for a long time in milk and milk products. Pasteurization of milk and milk products kills Brucella cells. The infectious dose for human infection is 10–100 cells. Symptoms of
brucellosis in humans include undulant fever with irregular rise and fall of temperature, profuse
sweats, body aches, aching joints, chills, and weakness. Symptoms appear in 3–21 days following
consumption of a contaminated food. Between 1983 and 1987, there were two outbreaks in the
United States from the consumption of imported cheese affecting 38 people with one death. The
CDC estimates about 839 cases of brucellosis in the United States annually and 50% of which are
foodborne. 29 Control measures for foodborne brucellosis include pasteurization of milk, manufacturing of dairy products from pasteurized milk, and proper sanitation to prevent recontamination
of pasteurized products.
Streptococcal Infection
Streptococcus pyogenes, in Group A, is a pathogen and has been isolated from lactating animals with
mastitis. It is a gram-positive coccus and has been associated with human pharyngitis with symptoms of sore throat, fever, chills, and weakness. In some cases, nausea, vomiting, and diarrhea can
Vibrio vulnificus 43
Vib. vulnificus is often responsible for serious septicemia and would cause infection. It is a gramnegative, lactose-positive, salicin-positive, halophilic bacteria found in the estuarine environment
in coastal waters globally. It is considered a highly lethal pathogen because of its ability to invade
the bloodstream. Vib. vulnificus has been associated with fulminating septicemia from the consumption of contaminated seafood as well as progressive cellulitis and tissue necrosis, resulting
from wound infection. Following consumption of contaminated seafood, in many cases raw oysters or clams, the cells penetrate the intestinal wall and produce primary septicemia in 20–40
hours. Vib. vulnificus produces several virulence factors, including the ability to survive stomach
acid, capsular polysaccharide, lipopolysaccharide, cytotoxins, pili, and flagellum, which allow the
bacterium to enter into the bloodstream to cause septicemia. Symptoms are chills, fever, and
prostration with occasional vomiting and diarrhea. The fulminating septicemia sets up rapidly,
which can be fatal in many cases. The infection and fatality rate is very high (40%–60%) among
people with liver and gastric diseases and immunodeficiencies. This organism can cause severe
wound infection in individuals with preexisting cuts, skin lesions, and punctures in the skin during swimming or during handling of seafoods (especially the fisherman). In severe cases, tissue
necrosis and secondary sepsis may develop; thus, surgical debridement or amputation may be
required. The fatality rate for wound infection is 20%–30% and is related to underlying conditions. Control measures should include methods discussed for Vib. parahaemolyticus. Susceptible
individuals should avoid consumption of raw seafoods, such as oysters.
Brucellosis 44
Human brucellosis is a zoonotic infection caused by Brucella spp., namely, Brucella abortus, Bru.
suis, and Bru. melitensis. They are Gram-negative, nonmotile, nonsporeforming, aerobic small rods
pathogenic to animals and humans. In infected animals, the organisms are located in the uterus
of pregnant animals and in the mammary glands of lactating females. Thus, the pathogens can
be excreted in milk. People working with animals can become infected with Brucella spp. Also,
people working with meat can be infected. Consumption of raw milk and some products made
from raw milk (such as some imported cheese) have been implicated in foodborne brucellosis. The
cells survive for a long time in milk and milk products. Pasteurization of milk and milk products kills Brucella cells. The infectious dose for human infection is 10–100 cells. Symptoms of
brucellosis in humans include undulant fever with irregular rise and fall of temperature, profuse
sweats, body aches, aching joints, chills, and weakness. Symptoms appear in 3–21 days following
consumption of a contaminated food. Between 1983 and 1987, there were two outbreaks in the
United States from the consumption of imported cheese affecting 38 people with one death. The
CDC estimates about 839 cases of brucellosis in the United States annually and 50% of which are
foodborne. 29 Control measures for foodborne brucellosis include pasteurization of milk, manufacturing of dairy products from pasteurized milk, and proper sanitation to prevent recontamination
of pasteurized products.
Streptococcal Infection
Streptococcus pyogenes, in Group A, is a pathogen and has been isolated from lactating animals with
mastitis. It is a gram-positive coccus and has been associated with human pharyngitis with symptoms of sore throat, fever, chills, and weakness. In some cases, nausea, vomiting, and diarrhea can