Gammaproteobacteria

Aeromonas hydrophilaAeromonas hydrophila. Gram stain.1977From Wikimedia Commons

Aeromonas hydrophilaAeromonas hydrophila isolated from blood culture from a patient with severe diarrhoea. Cultured on C.L.E.D. agar.28 February 2012.From Wikimedia Commons

This photomicrograph revealed stool exudates in a patient with shigellosis, which is also known as Shigella dysentery, or Bacterial dysentery.Created: 1980

Under a very high magnification of 25000X, this scanning electron micrograph (SEM) depicted a grouping of Gram-negative Legionella pneumophila bacteria. Please note that you’re able to see a number of the flagella emanating from these organisms. Please see PHIL 11092 through 11152 for additional SEMs of these organisms, specifically PHIL 11106 for a colorized version of this image, which better features the flagella.You’ll note that a number of these bacteria seem to display an elongated-rod morphology. L. pneumophila are known to most frequently exhibit this configuration when grown in broth, however, they can also elongate when plate-grown cells age, as it was in this case, especially when they’ve been refrigerated. The usual L. pneumophila morphology consists of stout, fat bacilli, which is the case for the vast majority of the organisms depicted here.Created: 2009

This urease test, based on the process involving the hydrolysis of urea, was performed to help identify the Gram-negative enteric bacterium Yersinia enterocolitica.Created: 1976

Under a very high magnification of 25000X, this colorized scanning electron micrograph (SEM) revealed the presence of a single Gram-negative Salmonella typhimurium bacterium, which was imaged right at the point where it was undergoing the process of cell division, resulting in the formation of two separate organisms. This dividing bacterium had been isolated from a pure culture. See PHIL 10994 for a black and white version of this image.Created: 2009

Under a moderately-high magnification of 5356X, this scanning electron micrograph (SEM) depicted a grouping of Gram-negative Legionella pneumophila bacteria. Note that in some of these views you’re able to see a number of the flagella emanating from these organisms. Please see PHIL 11092 through 11152 for additional SEMs of these organisms, specifically PHIL 11104 for a colorized version of this image.You’ll note that a number of these bacteria seem to display an elongated-rod morphology. L. pneumophila are known to most frequently exhibit this configuration when grown in broth, however, they can also elongate when plate-grown cells age, as it was in this case, especially when they’ve been refrigerated. The usual L. pneumophila morphology consists of stout, fat bacilli, which is the case for the vast majority of the organisms depicted here.Created: 2009

This photograph depicts the colonial growth pattern displayed by the Gram-negative enteric bacterium Yersinia enterocolitica cultivated on this triple sugar iron agar (TSI) medium.Created: 1976

Under a very high magnification of 20000X, this colorized scanning electron micrograph (SEM) revealed the presence of a single Gram-negative Salmonella typhimurium bacterium that had been isolated from a pure culture. See PHIL 10990 for a black and white version of this image.What sort of germ is Salmonella?Salmonella is actually a group of bacteria that can cause diarrheal illness in humans. They are microscopic living creatures that pass from the feces of people or animals to other people or other animals. There are many different kinds of Salmonella bacteria. Salmonella serotype Typhimurium and Salmonella serotype Enteritidis are the most common in the United States. Salmonella germs have been known to cause illness for over 100 years. They were discovered by an American scientist named Salmon, for whom they are named.Created: 2009

Under a moderate magnification of 1200X, this scanning electron micrograph (SEM) depicted a diffuse group of Gram-negative Legionella pneumophila bacteria. Please see PHIL 11092 through 11152 for additional SEMs of these organisms, specifically PHIL 11102 for a colorized version of this image.You’ll note that a number of these bacteria seem to display an elongated-rod morphology. L. pneumophila are known to most frequently exhibit this configuration when grown in broth, however, they can also elongate when plate-grown cells age, as it was in this case, especially when they’ve been refrigerated. The usual L. pneumophila morphology consists of stout, fat bacilli, which is the case for the vast majority of the organisms depicted here. These bacteria originated on a 1 week-old culture plate (+/- 1 day), which had incubated a single colony, at 37oC upon a buffered charcoal yeast extract (BCYE) medium with no antibiotics.Created: 2009

This photograph depicts the colonial growth pattern displayed by Yersinia enterocolitica bacteria growing on a blood agar plate (BAP) medium.Created: 1976

Under a moderately-high magnification of 8000X, this colorized scanning electron micrograph (SEM) revealed the presence of a grouping of Gram-negative Salmonella typhimurium bacteria that had been isolated from a pure culture. See PHIL 10988 for a black and white version of this image.How do people catch Salmonella?Created: 2009

Under a moderately-high magnification of 3500X, this scanning electron micrograph (SEM) depicted a scattered group of Gram-negative Legionella pneumophila bacteria. Please see PHIL 11092 through 11152 for additional SEMs of these organisms, specifically PHIL 11100 for a colorized version of this image.You’ll note that a number of these bacteria seem to display an elongated-rod morphology. L. pneumophila are known to most frequently exhibit this configuration when grown in broth, however, they can also elongate when plate-grown cells age, as it was in this case, especially when they’ve been refrigerated. The usual L. pneumophila morphology consists of stout, fat bacilli, which is the case for the vast majority of the organisms depicted here. These bacteria originated on a 1 week-old culture plate (+/- 1 day), which had incubated a single colony, at 37oC upon a buffered charcoal yeast extract (BCYE) medium with no antibiotics.Created: 2009

This photograph depicts the colonial growth pattern displayed by Yersinia enterocolitica bacteria growing on a Hektoen enteric (HE) agar medium; Y. enterocolitica is a non-lactose fermenter, and its colonies atop the HE agar are blue-green in color.Created: 1976

Under a moderately-high magnification of 8000X, this colorized scanning electron micrograph (SEM) revealed the presence of a small grouping of Gram-negative Salmonella typhimurium bacteria that had been isolated from a pure culture. See PHIL 10986 for a black and white version of this image.How do people catch Salmonella?Created: 2008

Under a high magnification of 8000X, this scanning electron micrograph (SEM) depicted a grouping of Gram-negative Legionella pneumophila bacteria. Please see PHIL 11092 through 11152 for additional SEMs of these organisms, specifically PHIL 11097 for a colorized version of this image.You’ll note that a number of these bacteria seem to display an elongated-rod morphology. L. pneumophila are known to most frequently exhibit this configuration when grown in broth, however, they can also elongate when plate-grown cells age, as it was in this case, especially when they’ve been refrigerated. The usual L. pneumophila morphology consists of stout, fat bacilli, which is the case for the vast majority of the organisms depicted here. These bacteria originated on a 1 week-old culture plate (+/- 1 day), which had incubated a single colony, at 37oC upon a buffered charcoal yeast extract (BCYE) medium with no antibiotics.Created: 2009

This photograph depicts the colonial growth pattern displayed by Yersinia enterocolitica bacteria growing on a Xylose Lysine Sodium Deoxycholate (XLD) agar plate.Created: 1976

Under a magnification of 2500X, this colorized scanning electron micrograph (SEM) revealed the presence of a large number of Gram-negative Salmonella typhimurium bacteria that had been isolated from a pure culture. See PHIL 10984 for a black and white version of this image.How do people catch Salmonella?What can I do to prevent salmonellosis?- Cook poultry, ground beef, and eggs thoroughly. Do not eat or drink foods containing raw eggs, or raw (unpasteurized) milk.- If you are served undercooked meat, poultry or eggs in a restaurant, don't hesitate to send it back to the kitchen for further cooking.- Wash hands, kitchen work surfaces, and utensils with soap and water immediately after they have been in contact with raw meat or poultry.- Be particularly careful with foods prepared for infants, the elderly, and the immunocompromised.Created: 2009

Under a high magnification of 6500X, this scanning electron micrograph (SEM) depicted a large group of Gram-negative Legionella pneumophila bacteria. Please see PHIL 11092 through 11152 for additional SEMs of these organisms, and specifically PHIL 11095 for a colorized version of this image.You’ll note that a number of these bacteria seem to display an elongated-rod morphology. L. pneumophila are known to most frequently exhibit this configuration when grown in broth, however, they can also elongate when plate-grown cells age, as it was in this case, especially when they’ve been refrigerated. The usual L. pneumophila morphology consists of stout, fat bacilli, which is the case for the vast majority of the organisms depicted here.Created: 2009

This photograph depicts the colonial growth pattern displayed by the isolated Gram-negative bacteria Citrobacter freundii on a Xylose Lysine Sodium Deoxycholate (XLD) agar plate.Created: 1976

Under a very high magnification of 12000X, this colorized scanning electron micrograph (SEM) revealed the presence of a large grouping of Gram-negative Salmonella typhimurium bacteria that had been isolated from a pure culture. See PHIL 10982 for a black and white version of this image.How do people catch Salmonella?Salmonella live in the intestinal tracts of humans and other animals, including birds. Salmonella are usually transmitted to humans by eating foods contaminated with animal feces. Contaminated foods usually look and smell normal. Contaminated foods are often of animal origin, such as beef, poultry, milk, or eggs, but any food, including vegetables, may become contaminated. Thorough cooking kills Salmonella. Food may also become contaminated by the hands of an infected food handler who did not wash hands with soap after using the bathroom.Created: 2009

Under a high magnification of 6500X, this scanning electron micrograph (SEM) depicted a large grouping of Gram-negative Legionella pneumophila bacteria. Please see PHIL 11092 through 11152 for additional SEMs of these organisms, and specifically PHIL 11093 for a colorized version of this image.You’ll note that a number of these bacteria seem to display an elongated-rod morphology. L. pneumophila are known to most frequently exhibit this configuration when grown in broth, however, they can also elongate when plate-grown cells age, as it was in this case, especially when they’ve been refrigerated. The usual L. pneumophila morphology consists of stout, fat bacilli, which is the case for the vast majority of the organisms depicted here.Created: 2009

This photograph depicts the colonial morphology displayed by Gram-negative, facultatively anaerobic Citrobacter freundii bacteria cultivated on a blood agar plate (BAP).Created: 1976

Under a moderately-high magnification of 8000X, this colorized scanning electron micrograph (SEM) revealed the presence of a large grouping of Gram-negative Salmonella typhimurium bacteria that had been isolated from a pure culture. See PHIL 10980 for a black and white version of this image. How can Salmonella infections be treated??Salmonella infections usually resolve in 5-7 days and often do not require treatment other than oral fluids. Persons with severe diarrhea may require rehydration with intravenous fluids. Antibiotics, such as ampicillin, trimethoprim-sulfamethoxazole, or ciprofloxacin, are not usually necessary unless the infection spreads from the intestines. Some Salmonella bacteria have become resistant to antibiotics, largely as a result of the use of antibiotics to promote the growth of food animals.Created: 2009