bacterial infections and antibiotic resistance

How do antibiotics work, on what cell structures?

antibiotics target bacterial structures such as the cell wall, cell membrane, ribosomes, or DNA replication machinery.

they disrupt cell wall synthesis, protein synthesis, or nucleic acid function, leading to bacterial death.

THEY DO NOT AFFECT VIRUSES

What are 3 examples of normal human flora?

staphylococcus aureus (nasal passages)

streptococcus mutans (mouth)

Escherichia coli (large intestine)

what is the advantage of having human flora?

they synthesize vitamins (b12 and K),

aid in digestion,

prevent colonization by pathogens,

and produce substances that inhibit harmful bacteria 

what are some classes of pathogenic bacteria?

actinomycetes (gram positive, purple, cell walls)

firmicutes (gram positive mostly, gut microbiota)

proteobacteria (gram negative, free living)

cyanobacteria (photosynthetic aquatic)

spirilla—transmitted by water/uncooked food

treponema pallidum—STIs

Borrelia Burgdorferi—lymes

how do vibrios move and where do they normally live?

vibrios are gram-negative rods that move with flagella and live in fresh and salt water

target intestines and cause diarrhea and dehydration

how is cholera transmitted? where does it affect the host? what are they symptoms?

cholera is transmitted through contaminated water, affects the intestinal tract, and causes watery diarrhea, dehydration and possible death

how is typhoid transmitted? where does it affect the host? what are the symptoms?

typhoid fever spreads via the fecal-oral route through contaminated food or water. it affects the intestines, liver and spleen and multiplies in the lymph nodes

. symptoms include fever, fatigue, abdominal pain, rose spots, diarrhea or constipation, and severe cases may lead to perforation or hemorrhage.

how is conjunctivitis transmitted? where does it affect the host? what are the symptoms?

conjunctivitis spreads through direct contact or contaminated objects, affects the eye’s conjunctiva, and causes redness, swelling, and pus-like discharge. 

what are the two common bacteria seen with conjunctiva?

staphylococcus aureus and streptococcus pneumoniae

how is necrotizing fasciitis transmitted ? Where does it affect the host? What are the symptoms?

it enters through cuts, punctures, or surgery, affecting connective tissue. symptoms include severe pain, fever, chills, tissue necrosis and sepsis

how is leprosy transmitted? where does it affect the host? what are the symptoms?

leprosy spreads through prolonged contact. it affects skin and peripheral nerves, causing lesions, numbness, and deformities of hands, feet, and face

howis pertussis transmitted? where does it affect the host? what are the symptoms?

pertussis is spread via respiratory droplets, affects the respiratory tract, and causes severe coughing fits with a ‘whooping’ sound, vomiting, and possible pneumonia or seizures in infants 

how do lobar pneumonia, bronchopneumonia and interstitial pneumonia differ?

lobar pneumonia affects one or more lobes (usually streptococcus pneumoniae) bronchopneumonia is patchy and often secondary to other infections. interstitial pneumonia involves inflammation of the lung tissue and is often viral or chronic.

How is tuberculosis transmitted? Where does it affect the host? What are the symptoms?

TB spreads through airborne droplets, mainly affects lungs but can spread to other organs. symptoms: chronic cough, weight loss, fever, night sweats, and fatigueWh

Why are UTIs more common in women?

because the female urethra is shorter and closer to the rectum, allowing bacteria like E. coli easier access 

How is syphilis transmitted? Where does it affect the host? What are the symptoms?

syphilis is sexually transmitted, affects the genitals, skin and nervous system. symptoms: painless sores, rash, fever, and late-stage heart/brain damage

how is plague transmitted? where does it affect the host? what are the symptoms?

plague spreads by fleas or airborne dorplets. it affects the lymph nodes, blood and lungs. symptoms: swolled nodes, fever, chills, necrosis, and cough

what conditions can have either a bacterial or viral cause?

pneumonia, meningitis, and urinary tract infections

what are broad-spectrum anitbiotics?

antibiotics that kill a wide range of bacteria, including harmful and beneficial microbiota wha

what are the modes of action for antibiotics?

inhibit cell wall synthesis, inhibit protein synthesis, inhibit folate synthesis, inhibit DNA repication, or disrupt cell membranes 

What is the mode of action for penicillin? tetracyclines?

penicillin inhibits bacterial cell wall synthesis.

tetracyclines inhibit protein synthesis 

how do bacteria resist antibiotics?

through enzyme inactivation, efflux pumps, target site modification, blocking antibiotic entry or alternative enzyme pathways

what are the main causes of antibiotic resistance?

Overuse/misuse of antibiotics, using antibiotics for viral infections, not finishing prescriptions, prophylactic use in agriculture, and poor hygiene in hospitals.

1.       What occurs when you do not complete a round of antibiotics?

Partially resistant bacteria survive and multiply, leading to resistant infections that are harder to treat.

1.       Why are antibiotics not effective against viruses?

Viruses lack the cellular structures (cell walls, ribosomes, metabolism) that antibiotics target.

1.       Why is dosing and the timing of doses important for antibiotics?

Maintaining proper drug levels ensures bacteria are killed. Missed or incorrect doses promote resistance.

1.       What are the main pathogens displaying antibiotic resistance?

MRSA, VRE, C. difficile, Pseudomonas aeruginosa, E. coli, Acinetobacter baumannii, Klebsiella pneumoniae, Mycobacterium tuberculosis.

1.       What is MRSA? What infections are seen?

MRSA (Methicillin-resistant Staphylococcus aureus) causes skin infections, pneumonia, meningitis, and sepsis. It is resistant to most antibiotics except vancomycin.

1.       What is VRE? Where do most cases occur?

VRE (Vancomycin-resistant Enterococci) causes infections in blood, urine, and surgical wounds. Most cases occur in hospitals and long-term care facilities.

1.       What is C Difficile? What are the symptoms?

C. difficile is a hospital-acquired bacterium causing diarrhea and colon inflammation, often after antibiotic use. Symptoms: watery diarrhea, abdominal pain, and fever.