Identifying Bacteria - NCLEX-PN

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 by Yersinia pestis. Staphylococcus aureus causes skin infections, toxic shock, and food poisoning. _Bacillus anthraci_s causes anthrax, which is similar to plague, but does not cause buboes. Borrelia burgdorferi causes lyme disease., which presents as rash and arthralgia.

The colon is anaerobic and the bladder is aerobic. This fact explains why E. coli normally 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.

Bacteria are classified as either Gram positive or Gram negative. Gram positive bacteria stain purple because of their thick peptidoglycan cell wall. Staph and Strep groups are both Gram positive. Bacteria can then be organized based on their shape. Cocci are circular while bacilli are rectangular in shape. Staph grows in clusters.

While Proteus penneri and Proteus vulgaris do cause opportunistic infections in a small percentage of people, 90% of Proteus infections in humans are caused by Proteus mirabilis.

_Proteus myxofaciens is only found in insect hosts and does not infect humans.

Proteus mirabilis is a Gram-negative, facultatively anaerobic, rod-shaped (bacillus) bacteria. It produces large amounts of the enzyme urease, which is able to hydrolyze urea to ammonia, causing the distinctively high pH seen in the urine of individuals with a P. mirabilis infection.

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 rickettsii causes Rocky Mountain Spotted Fever, and is spread by dermacentor ticks. It causes fever, headache, muscle pain, and a rash. Borrelia burgdorferi is associated with Lyme disease, e_hrlichia chaffeensis_ is associated with human monocytotropic ehrlichiosis, andr_ickettsia helvetica_ is 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 C_ampylobacter jejuni._ There is no known association between S_taphylococcus aureus, Salmonella,_ or E.coli and Guillain-Barré syndrome.

The most commonly implicated bacteria in epiglottiits are H. influenzae type B, Streptococcus spp, and Staphylococcus aureus. _Campylobacter jejuni is a common cause of food poisoning.

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 rickettsii causes Rocky Mountain Spotted Fever, and is spread by dermacentor ticks. It causes fever, headache, muscle pain, and a rash. Borrelia burgdorferi is associated with Lyme disease, e_hrlichia chaffeensis_ is associated with human monocytotropic ehrlichiosis, andr_ickettsia helvetica_ is 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 C_ampylobacter jejuni._ There is no known association between S_taphylococcus aureus, Salmonella,_ or E.coli and Guillain-Barré syndrome.

The most commonly implicated bacteria in epiglottiits are H. influenzae type B, Streptococcus spp, and Staphylococcus aureus. _Campylobacter jejuni is a common cause of food poisoning.

The question requires the knowledge that Escherichia coli is a facultative, Gram negative, lactose fermenting bacteria. EMB (eosin methylene blue), or Mac (MacConkey) media is superior for isolating Escherichia coli because it is both selective and differential. Nutrient agar is neither selective nor differential. Selenium enriched media would not help identify this bacteria because Escherichia coli does 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 by Yersinia pestis. Staphylococcus aureus causes skin infections, toxic shock, and food poisoning. _Bacillus anthraci_s causes anthrax, which is similar to plague, but does not cause buboes. Borrelia burgdorferi causes lyme disease., which presents as rash and arthralgia.