Case study #1 NDM-1 is an enzyme that hydrolyzes and inactivates nearly all known β-lactam-class antibiotics. This enzyme requires a metallic ion, usually zinc, to catalyze the hydrolysis reaction. The gene encoding NDM-1 is found on a conjugative plasmid and is efficiently transferred to many Gram negative bacteria.   What term(s) in the case study description supports your understanding of the cellular target of these antibiotics (what term(s) supports your answer to the previous question)? 

PAMPs would be found on the surface of which of the following?

Extra credit case study In August 2014, a 68-year-old man sustained a deep bite to his left fourth and fifth fingers from his pet African gray parrot. The gentleman had a past medical history of chronic obstructive pulmonary disease, for which he took regular inhaled steroids. He was also severely affected by osteoarthritis, for which he took long-acting morphine as analgesia. A day following the parrot bite, he saw his family practitioner for a consultation. The practitioner noted a laceration over the fourth proximal interphalangeal phalanx (PIP) with reddening of the surrounding tissues, and a course of oral antibiotics that have a broad spectrum against most Gram positive and Gram negative bacteria was prescribed for a presumed diagnosis of bacterial cellulitis (skin infection)… In October 2015, the patient again visited his general practitioner with worsening fourth finger swelling and erythema and a new fleshy nodule on the dorsal aspect of the left wrist. In November 2015, a rheumatologist injected steroids into the fourth PIP joint. In December 2015, the fourth PIP wound reopened and his entire left hand became red and swollen. The orthopedic team performed an initial washout with debridement, and amputation was considered. In February 2016, a second washout was performed from which deep tissue swabs showed non-nucleated acid-fast bacilli on a smear. A comprehensive medical history taken in February 2016 revealed that, in addition to the African gray parrot, the patient kept tropical fish and had cleaned the fish tank thoroughly following the parrot bite. The organism identified as the cause of this man’s infection is a naturally occurring aquatic organism found in freshwater and salt water. In humans, it predominantly causes soft tissue infections following exposure to contaminated water. The most common presentation is “fish tank granuloma”, i.e., hand infection following exposure to fish tank water. The majority of cases have a preceding injury to the hand (e.g., bites, abrasions, or puncture wounds) prior to the exposure that allowed entry of the organism through the dermis and into the soft tissue.   Based on what you know about the cell structure of the etiological agent, is it likely that the fish tank water can be easily treated with disinfectants to kill the agent but not the fish?

Enterovirus-D68 (EV-D68) is a virus that can cause mild to severe respiratory symptoms, especially in children. Since 1987, small numbers of EV-D68 cases in the US have been reported regularly to CDC. The number of people with new, confirmed EV-D68 infection was much greater in 2014 than that reported in previous years. The term that best describes the status of EV-D68 in 2014 is

Which of the following applies to hyaluronidase?

Choose all that apply: Normal microbiota is found in humans in/on the

Match the type of infection to its proper description.

Case study #6 Clostridium botulinum is the causative agent of botulism. This Gram-positive, anaerobic bacillus is commonly found on plants, in soil and water, and in the intestinal tract of some animals. The main virulence factor of C. botulinum is botulism toxin, which is a protein neurotoxin that causes muscle paralysis. Death results from paralysis of respiratory muscles. Genetic analysis has led to the understanding that C. botulinum has acquired its toxin genes from lysogenic bacteriophages. Adults who ingest C. botulinum spores alone generally do not become ill. However, adult botulism will result after ingestion of food containing botulinum toxin. Boiling and common chemical treatments used for water denatures botulism toxin. Infantile botulism, rather, results after children under the age of one ingest foods, such as honey, which contains C. botulinum spores but no botulinum toxin. Once inside the infant gut, these spores germinate and botulism toxin is produced after colonization. Treatment for botulism requires injections of botulinum antitoxin, pre-made antibodies that are administered to the patient as quickly as possible.   Choose all that apply: Treatment for botulism

Case study #3 Dental caries (dental decay) is the result of solubilization (dissolving) of tooth enamel by acid. The microbes associated with cavities, usually the Gram-positive Streptococcus mutans and Lactobacillus species living in biofilms as plaque, produce organic acids as the waste product of a specific metabolic pathway. Regular tooth brushing and chewing gum after meals, which increases saliva production, and are the two leading methods that can be preformed daily to prevent tooth decay.   The increased saliva production is a mechanical defense that is triggered by chewing gum. This is part of

Case study #4 Plasmodium falciparum is the most virulent causative agent of malaria. This parasite has a trophozoite form that must undergo a life cycle within the gut of the female Anopheles mosquito to be naturally transmitted to the next host. The parasite also has separate trophozoite forms in the liver and blood of humans. If the malaria parasite is introduced into a pregnant woman, it can cross the placental barrier and infect the developing fetus. People at increased risk for malaria infection are children under 5 years old, pregnant women, and people with AIDS (active HIV infection).   Defend your answer to the previous question – why or why not would chloramphenicol, which binds to the 50S ribosomal subunit, be effective at treating a P. falciparum infection?