Botulism toxin inhibits acetylcholine release from the presynaptic nerve terminal, causing flaccid paralysis. Death in botulism exposure is generally due to respiratry failure.Tonic paralysis is the cause of respiratory arrest in other toxicity exposures, such as exposure to tetanus toxin.

Rickettsia rickettsiicauses Rocky Mountain Spotted Fever, and is spread by dermacentor ticks. It causes fever, headache, muscle pain, and a rash.Borrelia burgdorferiis associated with Lyme disease, ehrlichia chaffeensisis associated with human monocytotropic ehrlichiosis, andrickettsia helveticais associated (very rarely) with meningitis.

While all of the listed organisms can cause diarrhea,Cryptosporidium,a protozoa, is the most commonly isolated organism in HIV positive patients presenting with diarrhea.

30% of cases of Guillain-Barré are preceded by infection by Campylobacter jejuni.There is no known association between Staphylococcus aureus, Salmonella,orE.coliand Guillain-Barré syndrome.

The most commonly implicated bacteria in epiglottiits areH. influenzaetype B,链球菌spp,andStaphylococcus aureus.Campylobacter jejuniis a common cause of food poisoning.

The question requires the knowledge that大肠杆菌is a facultative, Gram negative, lactose fermenting bacteria. EMB (eosin methylene blue), or Mac (MacConkey) media is superior for isolating大肠杆菌because it is both selective and differential. Nutrient agar is neither selective nor differential. Selenium enriched media would not help identify this bacteria becauseEscherichiacolidoes not require this supplemented media to grow. Phenethyl alcohol can be used to select for anaerobic bacteria, which is of no utility in this situation.

Genital warts is caused by human papillomavirus. All other sexually transmitted infection is correctly matched with its causative agent.

The question stem describes bubonic plague which is caused byYersinia pestis.Staphylococcus aureuscauses skin infections, toxic shock, and food poisoning.Bacillus anthracis causes anthrax, which is similar to plague, but does not cause buboes.Borrelia burgdorfericauses lyme disease., which presents as rash and arthralgia.

The colon is anaerobic and the bladder is aerobic. This fact explains whyE. colinormally lives in an anaerobic environment, but can also survive aerobically. Facultative anaerobes normally live in anaerobic conditions but can adapt to aerobic conditions. Microaerophiles describes bacteria that are obligate aerobes, but are poisoned by high levels of oxygen and thus require specific oxygen levels to grow.

WhileProteus penneriandProteus vulgarisdo cause opportunistic infections in a small percentage of people, 90% ofProteusinfections in humans are caused byProteus mirabilis.

Proteus myxofaciens只存在于insect hosts and does not infect humans.