Case study #5 Listeria monocytogenes is a chemoheterotrophic facultative anaerobic Gram-positive bacterium that can act as a human pathogen or as a saprobe, depending on its environment. This bacillus-shaped cell is motile, moving with peritrichous flagella. This bacterium has a high salt tolerance and can multiply readily at 4 oC (refrigerator temperatures). L. monocytogenes is part of the normal gut microbiota of many farm animals, including cows. Deli meats, hot dogs, and unpasteurized cheese and milk are likely sources of this pathogen. Many antibiotics can be used to treat infection with L. monocytogenes, including drugs that target peptidoglycan biosynthesis, the small ribosomal subunit of bacteria, and folic acid biosynthesis.   What term(s) in the case study description supports your answer for what L. monocytogenes uses as a source of carbon and energy (what term(s) supports your answer to the previous question)?

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.   Zinc’s role in the NDM-1 enzyme is to act as a(n):

Choose the statement that best describes the benefits of microbial antagonism to the human host.

Which of the following would be considered a symptom?

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?

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