MicroPara

• Gastrointestinal tract infections to describe

  • Colitis
  • Dysentery
  • Enteritis
  • Gastritis
  • Gastroenteritis
  • Hepatitis
• Colitis


  Inflammation of the colon (large intestines)
• Dysentery


  Low-volume, painful, bloody diarrhea
• Enteritis


  Inflammation of the small intestines
• Gastritis


  Inflammation of the mucosal lining of the stomach
• Gastroenteritis


  Inflammation of the mucosal lining of the stomach and intestine
• Hepatitis


  Inflammation of the liver
• The digestive system is inhabited by many microorganisms. From the mouth down to the colon, these different ecosystems are occupied by site-specific microbial populations.
• The stomach, due to its acidity, acts as an effective sterilization chamber that limits the entry of microorganisms to the small intestines.
• Infections of the digestive system range from asymptomatic infections to life-threatening loss of fluids and electrolytes, or severe ulceration accompanied by intestinal perforation and hemorrhage.
• The clinical manifestations vary from one another.
• Factors that play important roles in the causation of infectious disease in the digestive system

  • Intact mucosal epithelium covering all parts of the digestive system
  • Early damage to the lining may lead to manifestations such as nausea and vomiting
  • Damage to the colon in the form of ulcerations allow the members of the normal flora to penetrate the deep tissue and disseminate through the bloodstream to other organs
  • Alteration of the acid barrier of the stomach by disease, surgery or drugs increases the survival of pathogens leading to infection
  • Changes in the composition of the normal flora allow the growth of pathogenic organisms
  • Certain bacteria, viruses, and parasites can cause disease even in the absence of predisposing factors due to their ability to produce virulence factors (e.g., toxin production)
• Mechanisms by which signs and symptoms of infections in the gastrointestinal tract are produced

  • Pharmacologic action
  • Local inflammation
  • Deep tissue invasion
  • Perforation
• Pharmacologic action


  Some bacteria produce toxins which may alter normal intestinal function without causing lasting damage to their target cells
• Local inflammation


  Invasion of the alimentary tract by microbes can lead to inflammation, usually limited to the epithelial layer but may spread to the deeper tissues
• Deep tissue invasion


  Certain organisms are able to spread to adjacent tissues and enter the bloodstream
• Perforation


  When the mucosal epithelium is perforated, the normal flora spills into sterile areas and invades deep tissues, often with serious consequence
• Unlike other exterior surfaces, the teeth are hard and do not shed surface cells allowing accumulation of masses of microorganisms and their products.
• These accumulations are called dental plaques and are involved in the formation of dental caries or tooth decay.
• Older, calcified deposits of plaque are called dental calculus or tartar.
• Dental caries


  The most important organism that causes dental caries is Streptococcus mutans, although other microorganisms may also be involved (e.g., Actinomyces and lactobacilli)
• Dental caries


  • S. mutans favors crevices or other sites on the teeth that are protected from the shearing action of chewing or from the flushing action of saliva
  • The lactic acid produced by the bacteria is not diluted or neutralized by saliva, and this breaks down the enamel of the teeth, leading to localized softening of the external enamel
  • If the initial penetration of the enamel by caries remains untreated, bacteria can penetrate the interior of the tooth eventually advancing into the pulp of the tooth
• Preventive measures against the development of dental caries

  • Minimal ingestion of sucrose
  • Brushing
  • Flossing
  • Regular dental visits to remove plaque
  • Use of fluoride
  • Use of mouthwash (chlorhexidine being the most effective)
• Periodontal disease


  A term used to describe conditions that are characterized by inflammation and degeneration of structures that support the teeth
• Gingivitis


  The reversible inflammation of the gingivae or gums, characterized by bleeding of the gums while brushing the teeth, due to overgrowth of supra-gingival plaque causing irritation to the tissues of the gums
• Organisms involved in gingivitis

  • Streptococci
  • Actinomycetes
  • Anaerobic gram-negative bacteria (Prevotella, Bacteroides, and Fusobacterium nucleatum)
• Periodontitis


  A chronic gum disease that can cause bone destruction and tooth loss, generally causing little discomfort, with the gums being inflamed and bleeding easily, and as the infection progresses, the bone and tissue that supports the teeth are destroyed, leading to loosening and loss of teeth
• Numerous bacteria may be involved in the infection of periodontitis.
• Acute necrotizing ulcerative gingivitis (Vincent's disease or trench mouth)


  A common serious infection of the mouth, characterized by pain that prevents normal chewing and may be accompanied by bad breath or halitosis, with the most common organism involved being Prevotella intermedia
• Oral thrush


  A condition caused by the fungus Candida albicans, which is part of the normal flora of the skin, mucous membranes, and gastrointestinal tract, consisting of white patches adherent to the oral mucosa
• Factors that predispose the development of oral thrush

  • Endocrine disturbances (e.g., diabetes)
  • Prolonged intake of antibiotics
  • Malnutrition
  • Malignancy
  • Immunosuppression
  • Prolonged use of steroids
• Diagnosis of oral thrush


  Inspection and confirmation by examination of scraped material under the microscope demonstrating the characteristic pseudohyphae
• Treatment of oral thrush

  Correcting the predisposing factor, avoiding unnecessary use of antibiotics, and using topical antifungal agents (drug of choice is nystatin)
• Mumps (Epidemic Parotitis)

  A highly communicable disease characterized by painful inflammation of the salivary glands (more commonly the parotid gland), caused by the mumps virus, a member of the family Paramyxoviridae, with humans being the natural hosts
• Mode of transmission of mumps virus

  Transmitted via respiratory droplets
• Mumps


  • The disease occurs worldwide, affecting people who have not been vaccinated before the age of 15
  • Lifelong immunity occurs in persons who have had the disease
• Complications of mumps


  • Orchitis (inflammation of the testis)
  • Meningitis
• Orchitis


  A significant complication, especially if it occurs in post-pubertal males and if the involvement is bilateral, as it can lead to sterility
• Meningitis


  Usually benign and self-limited
• Laboratory diagnosis of mumps

  1. Virus isolation from saliva, spinal fluid, or urine

  2. Measurement of antibody titers