67 Questions
All of the ff. antibiotics acts directly on the cell membrane of the microorganism, except?
Aminoglycosides
Among the listed antibiotics, which ones inhibit the synthesis of bacterial cell walls?
Penicillin, Cephalosporins, Carbapenems
Which antibiotics are agents that disrupt the function of ribosomal subunits to inhibit protein synthesis?
Chloramphenicol, Tetracyclines, Erythromycin, Clindamycin
Which antibiotics specifically affect bacterial nucleic acid metabolism by inhibiting RNA polymerase?
Rifampicin, Rifabutin, Quinolones
Which mechanism of action does sulfonamide antibiotics primarily target?
Folate metabolism
Which antibiotic class binds to the 30S ribosomal subunit to cause bacterial cell death?
Aminoglycosides
Which bacterial pathway is targeted by trimethoprim and sulfonamides to inhibit growth?
Folate metabolism
Which antimicrobial agent is highly active against susceptible gram-positive cocci?
Penicillin G (IV) and V (oral)
What do Penicillinase-resistant penicillins like Nafcillin target?
Penicillinase-producing Staphylococcus aureus
Which antibiotic class is known for having an improved gram-negative spectrum, especially when combined with a beta-lactamase inhibitor?
Ampicillin
Which type of antibiotic has activity against Pseudomonas aeruginosa?
Extended-spectrum penicillin
Which part of the penicillin molecule is responsible for the loss of significant antibacterial activity when chemically altered?
Thiazolidine ring connected to the beta-lactam ring
What is the chief structural requirement for biological activity in penicillin?
The penicillin nucleus
Which component of the penicillin molecule determines many antibacterial and pharmacological characteristics?
Side chain (R)
What is inhibited by beta-lactam antibiotics like penicillin in bacterial cells?
Transpeptidation reaction
All are mechanisms that cause resistance to penicillin and other beta-lactams, except?
Enhanced resistance to antibiotics
How does amoxicillin differ from most oral penicillins in terms of absorption?
Requires an empty stomach for administration
Which pharmacological characteristic is associated with highly protein-bound penicillin like nafcillin?
Lower free-drug concentrations in serum
What is the effect of benzathine and procaine penicillin being formulated to delay absorption?
Prolonged blood and tissue concentrations
Penicillin poorly distributed except in cases of meningitis, EXCEPT?
Breast milk
How is Nafcillin primarily cleared from the body?
Biliary excretion
Main route of elimination for Oxacillin, Dicloxacillin, and Cloxacillin, EXCEPT?
Sputum and Milk excretion
What percentage of renal excretion of Penicillin occurs through glomerular filtration?
10%
What type of bacteria are penicillin-resistant to, despite having greater activity against gram-negative bacteria?
Staphylococci b-lactamase producing
Which antibiotic is DOC for infections caused by Treponema pallidum and many other spirochetes?
Penicillin
Which oral b-lactam antibiotics are most active against penicillin-resistant pneumococci?
Ampicillin and Amoxicillin
Which type of bacteria can extended spectrum penicillins target with the addition of a b-lactamase inhibitor?
Both gram-positive and gram-negative bacteria
What is the role of extended spectrum penicillins in combination with ESP?
They assist in absorption into the cell wall
Which of the following is NOT an adverse reaction associated with penicillins?
GI upset
In what condition should creatinine levels be before administering high doses of penicillin?
Normal
What adverse reaction can high doses of penicillin cause in patients with renal failure?
Seizures
Which bacterial genus is NOT sensitive to First Generation Cephalosporins?
Bacteroides
These bacterial species are inactive against First Generation Cephalosporins, EXCEPT?
E. coli
Which bacterial group is specifically mentioned as NOT being active against Cephalosporins & Cephamycins?
Enterococci
What is a characteristic of intramuscular administration of second-generation cephalosporins?
Avoided due to pain
For patients with renal issues, what adjustment is typically required in the dosage of oral first-generation cephalosporins?
Reduce the dosage
Which antibiotic is cited as an alternative to anti-staphylococcal penicillin for patients allergic to penicillin?
Cefazolin
What is the suggested primary use for first-generation cephalosporins?
Surgical prophylaxis
Which second-generation cephalosporin is mentioned as the most commonly used in the text?
Cefuroxime
What is the main reason why cefaclor is not popular these days according to the text?
Drug resistance
Which type of infections should second-generation cephalosporins be used cautiously?
Penicillin resistant pneumococci
How is excretion primarily carried out for oral first-generation cephalosporins like cephalexin, cephradine, and cefadroxil?
Through glomerular filtration and tubular secretion into urine
What is a common route of elimination for second-generation cephalosporins?
Renal clearance
Which bacterium type are second-generation cephalosporins primarily used to target?
Anaerobes
Which bacterial strains can oral second-generation cephalosporins primarily treat?
Beta-lactamase-producing Haemophilus influenzae
What is the main reason for using Cefuroxime in the treatment of community-acquired pneumonia?
Effectiveness against beta-lactamase-producing Klebsiella pneumoniae
Which 3rd generation cephalosporins have useful activity against P. aeruginosa?
Cefoperazone and Ceftazidime
What is the primary route of excretion for ceftriaxone and cefoperazone?
Biliary tract
Which body fluids and tissues do 3rd generation cephalosporins penetrate well?
Cerebrospinal fluid
What is the primary characteristic of MONOBACTAMS that differentiates them from other beta-lactam antibiotics?
They have a thiazolidine ring far from the beta-lactam ring
Which 3rd generation cephalosporins are approved treatment for meningitis?
Ceftriaxone and cefotaxime
What is a common adverse effect associated with 4th generation Cephalosporins?
Local irritation at the injection site
BLI are Not good inhibitors of class C b-lactamase (render less productive), produced by EXCEPT?
Bacteroides and Branhamella
Cephalosporins that contain a methylthiotetrazole group frequently cause?
Hypoprothrombinemia and bleeding disorders
What is the notable feature of 4th generation Cephalosporins regarding their resistance to hydrolysis by b-lactamases?
They are more resistant than 1st generation Cephalosporins
What is a demonstrated renal toxicity associated with some 4th generation Cephalosporins?
Interstitial nephritis
Which group of bacteria are 3rd generation cephalosporins NOT reliably active against?
Enterobacter species
Which statement regarding the activity of MONOBACTAMS is NOT true?
They have a wide spectrum of activity against both gram-positive and gram-negative bacteria
All bacterial strains are most affected by Ambler Class A BETA LACTAMASE INHIBITORS, EXCEPT?
N. gonorrhoeae and Serratia
Which bacteria are 4th generation Cephalosporins highly active against?
Pseudomonas aeruginosa and Haemophilus influenzae
In which type of infections are combinations of beta-lactam antibiotics with beta-lactamase inhibitors often indicated?
Mixed aerobic and anaerobic infections in intra-abdominal regions
Antibiotic of choice for treatment of Enterobacter infections because it is resistant to destruction by the b-lactamase produced by these organisms?
Carbapenems
What is the primary reason for the low urinary concentrations of Imipenem?
Inactivation by renal dehydropeptidases
Which carbapenem is resistant to most b-lactamases but not metallo-b-lactamases?
Imipenem
What is a distinguishing feature of Meropenem compared to Imipenem?
Greater activity against gram-positive organisms
What is the primary advantage of Meropenem over Imipenem in terms of renal clearance?
Not significantly degraded by renal dehydropeptidase
What determines the antibacterial spectrum of the combination of a beta-lactam antibiotic with a beta-lactamase inhibitor?
The companion penicillin in the combination
Test your knowledge about the unique characteristics of the bacterial cell wall, including the presence of a peptidoglycan layer, selective permeability, bacterial appendages, and research on antibody attack strategies.
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