ANTIBIOTICS

2. • A typical prokaryotic chromosome consists of a circular molecule of DNA localized in a
region of the cytoplasm called the nucleoid. With few exceptions, no membrane
surrounds a nucleoid, though the chromosome is packed insuch a way that a distinct
boundary is visible between the nucleoid and the rest of the cytoplasm. Chromosomal
DNA is folded into loops that are 50,000–100,000 bp long,held in place by molecules of
protein and RNA.
• Archaeal DNA is wrapped around globular proteins called Non-histones. The enzyme
gyrase further folds and supercoils the entire prokaryotic chromosome like a skein of
yarn into a compact mass.
• In addition to chromosomes, many prokaryotic cells contain one or more plasmids,
which are small molecules of DNA that replicate independently of the chromosome.
Plasmids are usually circular and 1–5% of the size of a prokaryotic chromosome,
ranging in size from a few thousand bp to a few million bp. Each plasmid carries
information required for its own replication, and often for one or more cellular
traits.Typically, genes carried on plasmids are not essential for normal metabolism, for
growth, or for cellular reproduction but can confer advantages to the cells that carry
them.

3. • Fertility (F) plasmids carry instructions for conjugation, a process involved in
transferring genes from one bacterial cell to another.
• Resistance (R) plasmids carry genes for resistance to one or more antimicrobial drugs
or heavy metals. By processes we will discuss shortly, certain cells can transfer
resistance plasmids to other cells, which then acquire resistance to the same
antimicrobial chemicals. One example of the effects of an R plasmid involves strains of
Escherichia coli that have acquired resistance to the antimicrobials ampicillin,
tetracycline, and kanamycin from a strain of the bacterium Pseudomonas.
• Virulence plasmids carry instructions for structures, enzymes, or toxins that enable a
bacterium to become pathogenic. For example, E. coli, a normal resident of the human
gastrointestinal tract, causes diarrhea only when it carries plasmids that code for
certain toxins.

5. • Chemotherapeutic agents (synthetic antibiotics) are antimicrobial agents of synthetic
origin useful in the treatment of microbial or viral disease. Examples: sulfonilamides,
isoniazid, ethambutol, AZT, nalidixic acid and chloramphenicol.
• Five modes of action of chemotherapeutic drugs. Various antimicrobial agents act by
interfering with:
• (1) cell wall synthesis
• (2) plasma membrane integrity
• (3) Nucleic acid synthesis
• (4) Ribosomal function
• (5) folate synthesis.

6. • Antibiotics are chemicals that kill or inhibit the growth of bacteria and are used to treat
bacterial infections. They are produced in nature by soil bacteria and fungi.
• They may be of two types of antibiotic action .They are :
1)Bacteriostatic
2)Bacteriocidal
• Bacteriostatic: Capable of inhibiting the growth or reproduction of bacteria.
Examples: Tetracyclines, macrolides, clindamycin, trimethoprim/sulfamethoxazole,
linezolid, and chloramphenicol .
• Bactericidal: capable of killing bacteria including complete cell.
Examples: Daptomycin, fluoroquinolones, metronidazole, nitrofurantoin, co-
trimoxazole, telithromycin.

9. List of Antibiotic Classes (Types of Antibiotics)
• Penicillins
• Tetracyclines
• Cephalosporins
• Quinolones
• Lincomycins
• Macrolides
• Sulfonamides
• Glycopeptides
• Aminoglycosides
• Carbapenems

10. 1)Penicillins
Another name for this class is the "beta-lactam" antibiotics, referring to their structural formula. The
penicillin class contains five groups of antibiotics: aminopenicillins, antipseudomonal penicillins, beta-
lactamase inhibitors, natural penicillins, and the penicillinase resistant penicillins.
Common antibiotics in the penicillin class include:
Generic Brand Name Examples
Amoxicillin Amoxil
Amoxicillin and clavulanate Augmentin, Augmentin ES-600
Ampicillin Unasyn
Dicloxacillin N/A
Oxacillin Bactocill
Penicillin V potassium Penicillin VK
Certain penicillinase-resistant penicillins (such as oxacillin or dicloxacillin) are inherently resistant to
certain beta-lactamase enzymes by themselves. Others, for example, amoxicillin or ampicillin have greater
antibacterial activity when they are combined with a beta-lactamase inhibitor like clavulanate, sulbactam,
or tazobactam.

12. 2. Tetracyclines
• Tetracyclines are broad-spectrum against many bacteria and treat conditions such as
acne, urinary tract infections (UTIs), intestinal tract infections, eye infections, sexually
transmitted diseases, periodontitis (gum disease), and other bacterial infections. The
tetracycline class contains drugs such as:
Generic Brand Name Examples
• Demeclocycline N/A
• Doxycycline Doryx, Doxy 100, Monodox, Oracea, Vibramycin
• Eravacycline Xerava
• Minocycline Amzeeq, Dynacin, Minocin, Minolira, Solodyn, Ximino, Zilxi
• Omadacycline Nuzyra
• Sarecycline Seysara
• Tetracycline Achromycin V

14. Cephalosporins
• There are five generations of cephalosporins, with increasing expanded coverage across the class
to include gram-negative infections. Newer generations with updated structures are developed to
allow wider coverage of certain bacteria. Cephalosporins are bactericidal (kill bacteria) and work
in a similar way as the penicillins.
• Cephalosporins treat many types of infections, including strep throat, ear infections, urinary tract
infections, skin infections, lung infections, and meningitis. Common medications in this class
include:
Generic Brand Name Examples Generation
• cefaclor N/A 2nd generation
• cefadroxil Duricef 1st generation
• cefdinir N/A 3rd generation
• cephalexin Keflex 1st generation
• cefprozil Cefzil 2nd generation
• cefdinir N/A 3rd generation
• cefepim Maxipime 4th generation

15. • cefiderocol Fetroja 4th generation
• cefotaxime N/A 3rd generation
• cefotetan Cefotan 2nd generation
• ceftaroline Teflaran 5th (next) generation
• ceftazidime Avycaz, Fortaz, Tazicef 3rd generation
• ceftriaxone N/A 3rd generation
• cefuroxime Ceftin, Zinacef 2nd generation
• The fifth generation (or next generation) cephalosporin known as ceftaroline (Teflaro)
is active against methicillin-resistant Staphylococcus aureus (MRSA). Avycaz contains
the the beta-lactamase inhibitor avibactam.

17. Fluoroquinolones
• The fluoroquinolones, also known as the quinolones, are a synthetic, bactericidal
antibacterial class with a broad-spectrum of activity used in adults (not children). Due to
risk of multiple serious side effects, the FDA has advised that they are not suitable for
common infections such as sinusitis, bronchitis, and uncomplicated urinary tract infections.
They should only be considered when treatment with other, less toxic antibiotics, has failed.
Ask your doctor about the warnings associated with this class of drug before you take it.
• The FDA has issued several strong warnings about this class due to potential disabling side
effects.
• Common drugs in the fluoroquinolone class include:
Generic Brand Name Examples
• ciprofloxacin Cipro, Cipro XR
• delafloxacin Baxdela
• levofloxacin N/A
• moxifloxacin Avelox
• gemifloxacin Factive
• Several fluoroquinolones are also available in drop form to treat eye or ear infections.

19. Lincomycins
• This class has activity against gram-positive aerobes and anaerobes (bacteria
that can live without oxygen), as well as some gram-negative anaerobes.
• The lincomycin derivatives may be used to treat serious infections like pelvic
inflammatory disease, intra-abdominal infections, lower respiratory tract
infections, and bone and joint infections. Some forms are also used topically on
the skin to treat acne. A single-dose vaginal cream is also available to treat certain
bacterial vaginal infections (bacterial vaginosis). These drugs include:
Generic Brand Name Examples
• clindamycin Cleocin, Cleocin T, Clindets, Clindesse, Evoclin
• lincomycin Lincocin

21. Macrolides
• The macrolides can be use to treat community-acquired pneumonia, pertussis
(whooping cough), or for uncomplicated skin infections, among other susceptible
infections. Ketolides are a newer generation of antibiotic developed to overcome
macrolide bacterial resistance.
• Frequently prescribed macrolides are:
Generic Brand Name Examples
• Azithromycin Zithromax
• Clarithromycin Biaxin
• Erythromycin E.E.S., Ery-Tab, Eryc
• Fidaxomicin (ketolide) Dificid

23. Sulfonamides
• Sulfonamides are effective against some gram-positive and many gram-negative
bacteria, but resistance is widespread. Uses for sulfonamides include urinary
tract infections (UTIs), treatment or prevention of pneumocystis pneumonia, or
ear infections (otitis media).
• Familiar names include:
Generic Brand Name Examples
• sulfamethoxazole and trimethoprim Bactrim, Bactrim DS, Septra
• sulfasalazine Azulfidine

25. Glycopeptide Antibiotics
• Members of this group may be used for treating methicillin-resistant
staphylococcus aureus (MRSA) infections, complicated skin infections, C.
difficile-associated diarrhea, and enterococcal infections such as endocarditis
which are resistant to beta-lactams and other antibiotics.
• Common drug names include:
Generic Brand Name Examples
• Dalbavancin Dalvance
• Oritavancin Orbactiv, Kimyrsa
• Telavancin Vibativ
• Vancomycin Firvanq, Vancocin

27. Aminoglycosides
• Aminoglycosides inhibit bacterial synthesis by binding to the 30S ribosome and
act rapidly as bactericidal antibiotics (killing the bacteria). These drugs are
usually given intravenously (in a vein through a needle); inhaled and
ophthalmic (eye) dose forms are also available. Examples in this class are:
Generic Brand Name Examples
• Gentamicin Genoptic, Gentak
• Tobramycin Aktob, Kitabis Pak, TOBI, Tobrex
• Amikacin Amikin, Arikayce

29. Carbapenems
• These injectable beta-lactam antibiotics have a wide spectrum of bacteria-killing power
and may be used for moderate to life-threatening bacterial infections like stomach
infections, pneumonias, kidney infections, multidrug-resistant hospital-acquired
infections and many other types of serious bacterial illnesses. They are often saved for
more serious infections or used as "last-line" agents to help prevent resistance.
• Members of this class include:
Generic Brand Name Examples
• Imipenem and cilastatin Primaxin, Recarbrio
• Meropenem Merrem Vabomere
• Ertapenem Invanz
• Note: Recarbrio is a combination medicine that contains imipenem, cilastatin and the
beta-lactamse inhibitor relebactam. Vabomere is a combination product that contains
meropenem and the beta-lactamse inhibitor vaborbactam.

31. • Amoxicillin
• Doxycycline
• Cephalexin
• Ciprofloxacin
• Clindamycin
• Metronidazole
• Azithromycin
• Sulfamethoxazole and trimethoprim
• Amoxicillin and clavulanate
• Levofloxacin
*(All these antibiotics are already mentioned in above slides)

32. Thankyou for your attention