Yersinia pseudotuberculosis
Yersinia pseudotuberculosis is one of the three primary species within the Yersinia genus and is known to cause gastroenteritis, which can resemble appendicitis. This bacterium can be transmitted from animals to humans or through contaminated food, making it a significant public health concern. Typically, it resides in warm-blooded animals such as mammals and birds, serving as reservoirs for potential zoonotic infections. Symptoms of infection include abdominal pain, fever, and occasionally a skin rash, with a notable absence of diarrhea.
Infections usually manifest five to ten days after exposure and can last from one to three weeks. For those with weakened immune systems, the bacteria may enter the bloodstream, leading to severe complications like sepsis, which can have a high mortality rate. Diagnosis often involves culture and molecular testing due to the similar symptomatology to appendicitis. While many cases resolve without antibiotics, specific groups may require treatment with medications like fluoroquinolones or aminoglycosides. Preventing Y. pseudotuberculosis infections relies heavily on good hygiene practices and careful food handling.
Yersinia pseudotuberculosis
Definition: causes an animal-transmitted or food-borne gastroenteritis whose symptoms mimic appendicitis
Y. pseudotuberculosis is one of the three mainYersinia bacterium species. It causes an animal-transmitted or food-borne gastroenteritis whose symptoms mimic appendicitis.
Microscopically, Y. pseudotuberculosis shows as an ovoid-shaped cell (coccobacillus) that stains gram-negative (red) during a Gram stain. If cultured from infected persons, it tends to grow slowly and form small, translucent, gray colonies. The cells have multiple flagella that allow them to move rapidly at low temperatures. At higher temperatures that approximate that of the human body95 degrees Fahrenheit, or 35 degrees Celsiusthe species is nonmotile.
Causes
Upon introduction to the gastrointestinal tract, the organism invades the wall of the lower small intestine and usually colonizes the lymphatic system associated with the intestines (causing mesenteric lymphadenitis).
Risk Factors
Y. pseudotuberculosis normally lives in warm-blooded animals. Mammals such as dogs, cats, cattle, horses, rabbits, deer, rodents, and birdssuch as turkeys, geese, ducks, cockatoos, and canariescan act as reservoirs of this organism. Contact with animals that carry Y. pseudotuberculosis can cause zoonotic infectionsdiseases transmitted from animals to humans. Likewise, the consumption of food prepared from animals that harbor the bacterium can cause food-borne infections. Drinking water from wells, streams, or other water sources, including those contaminated with bacterium-containing soil, also can lead to Y. pseudotuberculosis infections.
Symptoms
The symptoms of Y. pseudotuberculosis infection are a triad of abdominal pain in the lower right quadrant, a fever, and sometimes a skin rash, but diarrhea is rather uncommon. Symptoms usually appear five to ten days after infection and can last one to three weeks in healthy persons without treatment.
In persons with poorly functioning immune systems or liver disorders that cause excessive blood-iron concentrations, the organism can colonize the blood, leading to sepsis. In such cases, mortality rates exceed seventy-five percent.
Screening and Diagnosis
Because of the location of the abdominal pain, Y. pseudotuberculosis gastroenteritis is commonly confused with appendicitis. Y. pseudotuberculosis may be diagnosed through culture, polymerase chain reaction (PCR) tests, and serological testing.
Treatment and Therapy
Most Y. pseudotuberculosis infections do not require antibiotic treatment, but drug therapy is essential for children or adults with preexisting conditions that make sepsis likely.
Fluoroquinolones are often considered first-line treatment for Y. pseudotuberculosis infections, especially ciprofloxacin. Trimethoprim-sulfamethoxazole is also a common treatment. Aminoglycoside antibiotics, such as streptomycin sulfate, tobramycin, and gentamicin, can treat Y. pseudotuberculosis infections, but the toxicity of these drugs to the kidneys and ears limits their long-term usefulness. Bacterial cell-wall inhibitors such as the beta-lactam antibiotic pipericillin or the third-generation cephalosporin cefotaxime show consistent activity against Y. pseudotuberculosis. The bacterial protein-synthesis inhibitor chloramphenicol is effective against Y. pseudotuberculosis but should be used only as a last resort because it can damage bone marrow and cause aplastic anemia.
Combinations of antibiotics are also efficacious against Y. pseudotuberculosis infections. For example, a combination of cefotaxime and the quinolone antibiotic levofloxacin has effectively treated persons with bacteremia caused by Y. pseudotuberculosis.
Prevention and Outcomes
Prevention involves proper hygiene and food preparation and the avoidance of other sources of infection.
Bibliography
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