BIO 2100 Unit 10 Note Guide Clinical Microbiology & BacterialViral Infections – Wilkerson (Galen College of Nursing) 2026

USLO 10.1 Vocabulary to define: • Pleomorphic-capable of having a variety of shapes • Endothelial cells-an epithelial cell found in blood vessels and lining the heart Bacterial Diseases of the digestive system • Bacillus cereus o Disease associated with pathogen-food poisoning/intoxication-found in pasta or rice o Signs and symptoms-symptoms begin within a few hours & include nausea, pain & abdominal cramps. Vomiting or diarrhea may also be present depending on the enterotoxin present. Has been known to cause death. o Virulence Factors-makes 2 enterotoxins ▪ One causes vomiting ▪ Other causes diarrhea o Transmission-found in the soil & is often associated with grains. The bacteria in food will form and endospore. Vegetative bacteria make enterotoxins. Enterotoxins can be secreted into food that is left out too long or not cooked properly. o Treatment-antibiotics and fluids • Bacillus anthracis o Disease associated with pathogen-anthrax o Signs and symptoms-rare in the US, prompt treatment is necessary for good outcomes. Without treatment, gastrointestinal anthrax is fatal in about 40% of cases. o Virulence Factors-has a capsule, lethal toxin (LT), and edema toxin (ET). o Transmission-enters through the GI system causes gastrointestinal anthrax. Can be contracted through eating meat contaminated with the bacterium. o Treatment-antibiotics; penicillin, doxycycline, ciprofloxacin • Clostridium botulinum o Disease associated with pathogen-botulism o Signs and symptoms-nausea, vomiting, constipation, diarrhea, abdominal cramps, difficulty swallowing, drooping eyelids, blurred vision o Virulence Factors-usually the endospore of C. botulinum are in food and germinate within the food allowing the production of the neurotoxin. The person ingests the neurotoxin and enters the bloodstream causing the paralysis at the NMJ. Forms the neurotoxin BoNT. o Transmission-Associated with improperly canned foods. The neurotoxin is ingested through the digestive tract. o Treatment-Administration of the anti-toxin for the BoNT. This will only stop progression and not reverse any damage to the NMJ already done. Over time, neurological functions may be regained over a period of months or years. • Clostridium difficile o Disease associated with pathogen-C-diff infection o Signs and symptoms-toxins cause damage to intestinal tract causing a pseudomembranous colitis, watery and or bloody diarrhea, stomach cramping, dehydration, fever, and loss of appetite. In older people, death can result. o Virulence Factors-produced toxins TcdA and TcdB o Transmission-C. diff is part of the normal microbiota of normal healthy people. When antibiotics disrupt the balance of the normal intestinal microbiota, Clostridium difficile is allowed to overgrow causing symptoms. Also caused by unwashed hands. Hand sanitizer does not kill spores. o Treatment-Stopping antibiotics and using metronidazole or vancomycin. Other treatment options may include fecal transplant from a healthy donor. Probiotics can help to preserve the normal flora once the infection is under control. • Clostridium perfringens o Disease associated with pathogen-Gastroenteritis o Signs and symptoms-diarrhea and abdominal cramps usually develop within 8-12hrs and resolves within 24hrs o Virulence Factors-enterotoxins o Transmission-Found in undercooked food and the endospore will germinate and secrete enterotoxins. Endospores that are ingested can also germinate in the intestines. o Treatment-Supportive care and replacement of electrolytes • Escherichia coli o Disease associated with pathogen-food poisoning o Signs and symptoms—watery diarrhea, occasionally with a fever or vomiting o Virulence Factors-fimbriae allow attachment, more virulent strains produce enterotoxins, toxins are similar to cholera or shiga toxins o Transmission-Normal inhabitant of lower GI tract. The most common means of transmission is through contaminated food or water from improper hand hygiene. o Treatment-most are self-limiting and only require supportive care such as replacing electrolytes. Other more virulent strains may require antibiotics, but these are rarely used due to the risk of antibiotic resistance and the potential of hemolytic urea syndrome. • Helicobacter pylori o Disease associated with pathogen-peptic ulcers o Signs and symptoms-can be an inhabitant of some people and be asymptomatic. Symptoms are nausea, lack of appetite, burping, bloating, and weight loss. Some people will develop ulcers and some have risk of stomach cancer. o Virulence Factors-Produces toxins Vac A. Attached using pili. Produces an exoenzyme urease to neutralize stomach acid and allow for the bacteria to survive. o Transmission-Transmitted through contaminated food or water. Recent research has shown it is possible to transmit between people from close contact or sharing food and drink. o Treatment-Triple therapy with antibiotics and an antacid to decrease stomach acid that the bacteria prefer. • Salmonella