classes of antibacterials

2. ANTIBACTERIAL
CLASSIFICATION
&
DETAIL

3. Protein synthesis inhibitors
30S Amino
glycosides
(initiation
inhibitors)
-mycin (
Streptomyce
s)
Streptomycin
Neomycin (Framycetin, Paromomycin,
Ribostamycin)
Kanamycin (Amikacin, Arbekacin, Bekanamycin,
Dibekacin, Tobramycin)
Spectinomycin# · Hygromycin B
-micin
(Micromonos
pora
Paromomycin
Gentamicin# (Netilmicin, Sisomicin,
Isepamicin)Verdamicin
Astromicin
Tetracyclin
e
antibiotics
(tRNA
binding)
Tetracyclines Doxycycline# •Chlortetracycline • Clomocycline •
Demeclocycline • Lymecycline •
Meclocycline • Metacycline • Minocycline •
Oxytetracycline • Penimepicycline •Rolitetracyclin
e • Tetracycline
Glycylcycline
s
Tigecycline

4. Protein synthesis inhibitors
50
S
Oxazolidinone
(initiation inhibitors)
Linezolid •
Torezolid · Eperezolid · Posizolid · Radezolid
Peptidyl
transferase
Amphenicols Chloramphenicol# · Azidamfenicol · Thiampheni
col · Florfenicol
Pleuromutilin
s
Retapamulin · Tiamulin · Valnemulin
MLS (trans
peptidation/
translocatio
n
Macrolides Erythromycin# · Azithromycin# · Spiramycin · M
idecamycin ·Oleandomycin · Roxithromycin · Jo
samycin · Troleandomycin ·Clarithromycin · Mio
camycin · Rokitamycin · Dirithromycin ·Flurithro
mycin · Ketolide (Telithromycin, Cethromycin)
Lincosamides Clindamycin# · Lincomycin
Streptogrami
ns
Pristinamycin · Quinupristin/dalfopristin ·
Virginiamycin
EF-G
Steroidantibacterials Fusidic acid

5. Cell envelope antibiotics
Intracellular inhibit peptidoglycan subunit
synthesis and transport:
NAM synthesis
inhibition (Fosfomycin)
DADAL/AR inhibitors (Cycloserine)
bactoprenol inhibitors (Bacitracin
Glycopeptide inhibit PG chain elongation:
Vancomycin (Oritavancin,
Telavancin)
Teicoplanin (Dalbavancin) · Ramopla
nin

6. Cell envelope antibiotics
β-lac
tams
inhibit
PBP
cross-links
Peni
cillins
penams
Extende
d
sp.
Amino
penicillin
s
Amoxicillin , Ampicillin
Pivampicillin, Hetacillin, Bacampicillin,
Metampicillin, Talampicillin, Epicillin
Carboxy
penicillin
s
Carbenicillin (Carindacillin) · Ticarcillin ·
Temocillin
Ureido
penicillin
s
Azlocillin · Piperacillin · Mezlocillin
other: Mecillinam Pivmecillinam · Sulbenicillin
β-lacta
mase
sensitive
Benzylpenicillin (G):
Clometocillin · Benzathine .benzylpenicillin·
Procaine benzylpenicillin·
Azidocillin · Penamecillin
Phenoxymethylpenicillin (V)#:
Propicillin · Benzathine
phenoxymethylpenicillin · Pheneticillin

7. Cell envelope antibiotics
β-lac
tams
(inhibit
PBP
cross-links)
Penicillin
s
(penams)
Narrow
sp.
β-
lactamas
e
sensitive
BenzyL
penicillin
(G)#:
Clometocillin · Benzathine
benzylpenicillin# ·Procaine
benzylpenicillin# · Azidocillin ·
Penamecillin
Phenoxy
methyl
penicillin
(V)#:
Propicillin · Benzathine
phenoxymethylpenicillin ·
Pheneticillin
β-
lactamas
e
resistant
Cloxacillin
#
(Dicloxacillin, Flucloxacillin) ·
Oxacillin · Meticillin ·Nafcillin
Penems Faropenem
Carba
penems
Biapenem · Doripenem · Ertapenem · Imipenem · Meropenem ·
Panipenem

8. Cell envelope antibiotics
β-lac
tams
inhibit
PBP
cross-links
Cephalo
sporins
cephems
1st
(PEc
K)
# · Cefacetrile · Cefadroxil · Cefalexin · Cefaloglycin · C
efalonium ·Cefaloridine · Cefalotin · Cefapirin · Cefatriz
ine ·
Cefazedone · Cefazaflur ·Cefradine · Cefroxadine · Cef
tezole
2nd
(HEN
Cefaclor · Cefamandole · Cefminox · Cefonicid · Cefor
anide
Cefotiam ·Cefprozil · Cefbuperazone · Cefuroxime · Ce
fuzonam · cephamycin (Cefoxitin,Cefotetan, Cefmetaz
ole) ·
carbacephem (Loracarbef)
3rd Cefixime# · Ceftazidime# · Ceftriaxone# · Cefcapene · C
efdaloxime · Cefdinir ·Cefditoren · Cefetamet · Cefmen
oxime ·
Cefodizime · Cefoperazone ·Cefotaxime · Cefpimizole
·
Cefpiramide Cefpodoxime · Cefsulodin · Cefteram ·
Ceftibuten · Ceftiolene · Ceftizoxime · oxacephem
(Flomoxef, Latamoxef ‡)
4th Cefepime · Cefozopran · Cefpirome · Cefquinome

9. Cell envelope antibiotics
β-lac
tams
inhibit
PBP
cross-links
Monobactams Aztreonam ·
Tigemonam · Carumonam
β-lactamase inh. penam
(Sulbactam, Tazobactam) ·
clavam
(Clavulanic acid
Combinations Co-amoxiclav (Amoxicillin/clavulanic acid)
Imipenem/cilastatin·
Ampicillin/sulbactam(Sultamicillin) ·
Piperacillin/tazobactam
Other detergent
(Colistin, Polymyxin B)
depolarizing
(Daptomycin) ·
hydrolyze NAM-NAG
(Lysozyme)

10. Nucleic acid inhibitors
Antifolate
s
(inhibits
purine
metabolis
m,
thereby
inhibiting
DNA and
RNA
synthesis
DR
inhibitor
2,4-Diaminopyrimidine Trimethoprim#,
(Brodimoprim, Tetroxoprim, Iclaprim†)
Sulfo
namide
s
(DS
inhibitor
)
Short-acting
Sulfaisodimidine · Sulfamethizole · Sulfadimidin
e ·
Sulfapyridine ·Sulfafurazole · Sulfanilamide
(Prontosil) · Sulfathiazole · Sulfathiourea
Inter
mediate
acting
Sulfamethoxazole · Sulfadiazine# · Sulfamoxole
Long-acting
Sulfadimethoxine · Sulfalene · Sulfametomidine
·
Sulfametoxydiazine ·Sulfamethoxypyridazine ·
Sulfaperin · Sulfamerazine · Sulfaphenazole ·
Sulfamazone
Other/Un grouped sulfanilamide (Sulfacetamide, Sulfametrole)
Combinations Sulfamethoxazole and trimethoprim#

11. Nucleic acid inhibitors
Topo
isomeras
e
inhibitors
quinolon
es
inhibits
DNA
Repli
-cation
1st
gene
ration
Cinoxacin‡ · Flumequine · Nalidixic acid · Oxolinic
acid · Pipemidic acid · Piromidic acid ·Rosoxacin
Fluoro
Quino
lones
2nd
gene
ratio
n
Ciprofloxacin· Enoxacin· Fleroxacin· Lomefloxacin ·
Nadifloxacin ·Ofloxacin·Norfloxacin·Pefloxacin · Ruflo
xacin
3rd
gene
ratio
n
Balofloxacin · Grepafloxacin· Levofloxacin · Pazufloxa
cin ·
Sparfloxacin· Temafloxacin· Tosufloxacin
4th
gene
ratio
n
Besifloxacin · Clinafloxacin† · Garenoxacin · Gemiflox
acin · Moxifloxacin ·Gatifloxacin‡ ·
Sitafloxacin · Trovafloxacin‡/Alatrofloxacin‡ · Pruliflox
acin
Veterinary Danofloxacin · Difloxacin · Enrofloxacin · Ibafloxacin ·
Marbofloxacin ·Orbifloxacin · Pradofloxacin · Saraflox
acin
Related
Aminocoumarins: Novobiocin

12. Nucleic acid inhibitors
Anaerobi
c DNA
inhibitors
Nitro-imidazolederivatives
Metronidazole · Tinidazole · Ornidazole
Nitrofuran derivatives Furazolidone · Nitrofurantoin · Nifurtoinol
RNA synt
hesis
Rifamycins/
RNA polymerase
Rifampicin · Rifabutin · Rifapentine · Rifaxi
min
Other/ungrouped
Isoleucine- tRNA
ligase inhibitors
bornane: Xibornol
cresol: Clofoctol
polyamine: Methenamine
alpha hydroxy acid: Mandelic acid
nitroquinoline: Nitroxoline
pyran/fatty acid: (Mupirocin)

13. PENICILLINS
Penicillins are beta-lactam antibiotics derived
from 6-aminopenicillanic acid. The natural
penicillins include sodium and potassium
salts of benzyl penicillins. Semi synthetic
penicillins possess properties that improve
upon deficiencies of natural penicillins,
including wider antimicrobial spectrum and
decreased susceptibility to degradation by
gastric acids and beta-lactamase enzymes

14. MECHANISM OF ACTION:
 Beta-lactam antibiotics lyses bacteria by
binding to cytoplasmatic membrane enzymes
(penicillin-binding proteins). This inhibits a
step in peptidoglican synthesis that is crucial
for cell wall formation. All members of the
family have a beta-lactam ring and a
carboxyl group resulting in similarities in the
pharmacokinetics and mechanism of action
of the group members.

15. INDICATIONS, TOXICITY & DOSAGE:
 Omphalitis; Clostridial infections (necrotic
enteritis, gangrenous dermatitis),
Staphilococcosis, Pasteurellosis,
Ornithobacterium rhinotracheale
 Amoxycillin Chickens: 20 mg/kg bw
Generally low toxicity. All penicillins have
low toxicity in the normal sense of the
word.

16. DRUG INTERACTIONS:
 Penicillins+Aminoglycosides:There is an in vitro interaction
between aminoglycoside antibiotics and penicillins leading to a
significant loss of aminoglycoside antibacterial activity if these
antibiotics are mixed in the same bottle. The extend of inactivation
depends on the penicillin concentration, the contact time, and the
temperature. Aminoglycosides should not be mixed with penicillins
or cephalosporines in the same bottle.
 In vitro, penicillins interact chemically with the aminoglycoside
antibacterial to form biologically inactive amides by a reaction
between the amino groups on the Aminoglycosides and the beta-lactam
ring on the penicillins. Thus both antibacterial are
inactivated.
 Penicillins+Tetracyclines: The generally accepted explanation is
that bactericides, such as penicillin which inhibits bacterial cell wall
synthesis, require cells to be actively growing and dividing to be
maximally effective, a situation that will not occur in the presence
of bacteriostatic antibacterial such as the tetracyclines.

17. PHARMACOKINETICS:
 Amoxicillin is a semi synthetic derivative of penicillin
and an analog of ampicillin that displays a broad
spectrum of antibacterial activity against many gram-positive
and gram-negative organisms, inactivated by
beta-lactamases. Amoxicillin is absorbed better and
has more rapid action and greater resistance to the
gastric acid than ampicillin.
 When amoxicillin was administered orally to broilers
for 5 consecutive days, no significant differences were
observed between the elimination profiles in healthy
and diseased birds. The daily administration of
amoxicillin to laying hens at a dosage of 16 mg/kg bw
for 5 consecutive days was not found capable of
resulting in residues in eggs at concentrations above
0.007 ppm.

18. TETRACYCLINES
 Tetracyclines generally act as
bacteriostatic antibiotics. Broad spectrum
antibiotics with activity against Gram-positive
and Gram-negative bacteria.
Resistance is widespread. The
tetracyclines are a closely related group of
antibiotics with comparable
pharmacological properties but different
pharmacokinetic characteristics

19. MECHANISM OF ACTION:
 Tetracyclines inhibit bacterial protein
synthesis. Their site of action is the
bacterial ribosome - 30 S subunit, thereby
preventing binding to those ribosomes of
aminoacyl transfer-RNA. Active transport
of the drug into the bacterial cell must
occur in order for the drug to be effective.
Doxycycline enters the cell by passive
diffusion

20. SOURCE & INDICATIONS:
 Chlortetracycline S treptomyces
aureofaciens
 Oxytetracycline Streptomyces rimosus
 Doxycycline Semisynthetic
 Mycoplasma, Chlamydia, Pasteurella,
Ornithobacterium rhinotracheale,
Clostridium spp., Spirochetes and some
protozoa.

21. DOSAGE:
 Chickens:
Oxytetracycline 50 mg/kg
Doxycycline 25 mg/kg
 Doxycycline
 is a second generation tetracycline mainly active
against Gram-positive and Gram-negative aerobic
and anaerobic bacteria. Doxycycline has low
affinity for calcium and is relatively more stable in
aqueous solution. It has a high relative
liposolubility which readily compensates for the
high protein binding. Doxycycline has several
advantages over other tetracycline analogues:

22. DRUG INTERACTIONS:
 Co-administration of tetracyclines with
antacids or other drugs containing divalent
or trivalent cat ions, such as calcium,
magnesium, iron or sodium content, is
contraindicated. Tetracyclines form
complexes with such cat ions, which are
very poorly or not at all absorbed.
Incompatibility:
 Penicillins, cephalosporins.

23. PHARMACOKINETICS:
 Variations in clinical efficacy of individual
tetracyclines are attributable to differences
in their pharmacokinetic properties rather
than to differences in quantitative
susceptibility of micro-organisms. The
factor that underlies the pharmacokinetic
properties of tetracyclines is lipid solubility;
the degree of lipid solubility differs between
individual tetracyclines.

24. MACROLIDES
Description:
 A group of organic compounds that contain a
macrocyclic lactones ring linked glycosidically to
one or more sugar moieties.
 Mechanism of action: Binding to the 50S
subunit of the bacterial ribosome and inhibiting
translocation of peptidyl-tRNA from the A site to
the P site. The result of this inhibition is that
bacteria are not able to complete proteins that
are essential for life. Macrolides are
bacteriostatic.


25. SOURCE:
 Tylosin
 Streptomyces fradiae
 Tilmicosin
 Produced semi synthetically by chemical
modifications of desmycosin.
 Chemistry:
 Tylosin consists primarily of Tylosin factor A
with small amounts of three minor factors,
desmycosin (factor B), macrocin (factor C) and
relomycin (factor D). Tylosin factor A has the
highest microbiological potency.

26. INDICATIONS & DRUG INTERACTIONS:
Mycoplasmosis, Necrotic enteritis, O.R.T.
Dosage:
 Chickens:
Tylosin 50 mg/Kg Tilmicosin 20 mg/kg
Florfenicol and lincosamides have
mechanisms of action similar to the
Macrolides; they may be prevented from
binding, or prevent a Macrolides from
binding to the 50S subunit of bacterial
ribosomes.

27. RESIDUES
 Pharmacokinetics:
 Tylosin: Residue in tissues is very rare. It
is eliminated from the body upon
withdrawal of the drug.
 Tilmicosin: Liver should be the target
tissue for Tilmicosin residues in broiler
chickens. The recommended withdrawal
time is 10 days.
 Protein binding: chickens - 30%

28. FLUOROQUINOLONES
 The Fluoroquinolones are synthetic, broad-spectrum
antibacterial agents with
bactericidal activity. They exert their effects
by binding to and inhibiting bacterial DNA-gyrase.
This enzyme produces super coiling
of cellular DNA which is needed for bacterial
DNA synthesis.
 Description: The Fluoroquinolones are
broad-spectrum antibacterial agents with in
vitro activity against many gram-negative and
gram-positive organisms.

29. MECHANISM OF ACTION
 Quinolones rapidly inhibit DNA synthesis
by promoting cleavage of bacterial DNA in
the DNA-enzyme complexes of DNA
gyrase and type IV topoisomerase,
resulting in rapid bacterial death.(1-3) As a
general rule, gram-negative bacterial
activity correlates with inhibition of DNA
gyrase, and gram-positive bacterial
activity corresponds with inhibition of DNA
type IV topoisomerase.

30. INDICATIONS:
 Salmonellosis, Colibacillosis, Fowl cholera,
Pseudomonas aeruginosa (enrofloxacin)
 Dosage:
 Chickens:
 Enrofloxacin 10 mg/kg
 Danofloxacin 6 mg/kg
 Flumequine 18-20 mg/kg
 Norfloxacin 15 mg/kg
 Difloxacin 10 mg/kg

31. DRUG INTERACTIONS:
 Various drug-drug interactions can occur with
the use of the Quinolones. Absorption of the
Quinolones is significantly diminished with the
concomitant use of compounds that contain
multivalent metal cat ions such as aluminum,
magnesium, zinc, iron, and calcium.

32. AMINOGLYCOSIDES
Aminoglycosides are antibiotics that are highly effective
against gram-negative and to a lesser extent gram-positive
bacteria. Neomycin, among others, is effective against
Enterobacter, Salmonella and Shigella. Neomycin, is not
effective against Pseudomonas aeruginosa as opposed to
Gentamicin, which is. Aminoglycosides are ineffective
against fungi and yeast. Neomycin consists of a mixture of
Neomycin A, B and C, which differ in the side chains
attached to the amino sugars. Neomycin A is a degradation
product of Neomycin B and C, and has no antimicrobial
activity. Neomycin is an aminoglycoside antibiotic. It
consists of 78-88 % Neomycin B and 10-16 % Neomycin C.
Neomycin, had better activity than streptomycin against
aerobic gram-negative bacilli.

33. MECHANISM OF ACTION:
 The bactericidal effect of these antibiotics is
based on the inhibition of protein synthesis.
Aminoglycosides bind to the 30S subunit of
the bacterial ribosome, interfering with the
binding of fMet-tRNA and therefore the
formation of the initiation complex.
Attachment to the 30S subunit results in
stagnation of the initiation phase during
translation. Because of this stagnation
elongation can no longer take place and
protein synthesis stops.

34. SOURCE & INDICATIONS:
 Neomycin Streptomyces fradiae
 Streptomycin Streptomyces griseus
 Spectinomycin Streptomyces spectabilis
 Gentamicin Micromonospora purpurea
 Gentamicin: Its extended stability and slow
development of bacterial resistance allow
long-term virus and tissue culture studies.
Neomycin: Treatment of enteric infections.

35. DOSAGE:
Chickens:
Neomycin 70-140 g/ ton feed
Streptomycin 20 mg/kg; 2.5-5.0 mg /chick
Spectinomycin 50-100 mg/kg bw
Gentamicin sulphate 5.5 mg/kg IM, 0.2 mg/chick

36. PHARMACOKINETICS:
 Aminoglycosides are poorly absorbed from
the gastrointestinal tract. After parenteral
administration, Aminoglycosides are primarily
distributed within the extracellular fluid.
Penetration of biologic membranes is poor
because of the drug's polar structure, and
intracellular concentrations are usually low,
with the exception of the proximal renal
tubule.

37. TOXICITY
Repetitive dosing may result in renal
accumulation and toxicity. Nephrotoxicity
results from renal cortical accumulation
resulting in tubular cell degeneration and
sloughing.
Proximal acute tubular necrosis (ATN)
result in decrease GFR.
The use of Gentamicin or neomycin (Inj)
has been associated with polyureia,
polydispsia and Nephrotoxicity.

38. RESISTANCE & COMBINATIONS
 Via plasmid-mediated aminoglycoside-modifying
enzymes. Bacterial inactivation by
intracellular enzymes.
 Synergistic in combination with beta-lactams
and glycopeptides.
Spectinomycin can be combined with Colistin
or lincomycin.

39. DRUG-DRUG INTERACTIONS
 There is an in vitro interaction between
aminoglycoside antibiotics and penicillin's leading to a
significant loss of aminoglycoside antibacterial activity
if these antibiotics are mixed in the same bottle. The
extend of inactivation depends on the penicillin
concentration, the contact time, and the temperature.
Aminoglycosides should not be mixed with penicillins
or cephalosporines in the same bottle.
 Comments:
 The antimicrobial effect of the antibiotic depends on
the extracellular pH. Antimicrobial activity decreases
significantly at pH levels of 6.5 and lower. The
presence of divalent cat ions (Ca+2 and Mg+2) in the
medium also decreases the antimicrobial activity.

40. POLYPEPTIDES
Description & Mechanism of action:
 The polypeptides are bactericidal antibiotics
with activity against gram-negative aerobic
bacilli including Pseudomonas aeruginosa.
They are not active against Proteus sp and
have no activity against gram-positive
organisms.
 Polymyxin B, Colistin and bacitracin act by
disrupting the bacterial cell membrane
with leakage of intracellular materials and it
inhibits bacterial oxidative metabolism.

41. SOURCE:
Polymyxin B Bacillus polymyxa
Polymyxin E Bacillus polymyxa var.
Colistin Colistinus
Bacitracin Bacillus subtilis
Dosage Chickens:
Polymyxin B IM: 500,000-750,000 IU/kg
Colistin PO: IM: 60-80,000 IU/kg
Bacitracin
(broilers are more susceptible to the toxic
effects of the drug)

42. CHEMICAL STRUCTURE:
 Polymyxin B sulfate is the sulfate salt of Polymyxin B 1 and B 2 ,
which are produced by the growth of Bacillus polymyxa. It has a
potency of not less than 6,000 Polymyxin B units per mg,
calculated on an anhydrous basis.
 Polymyxin E was isolated from the culture of a strain of Bacillus
polymyxa var. Colistinus, also called "Colistin" due to his
excellent activity against E. coli.
 Colistin is no homogenous substance, but a mixture of the two
components Colistin A and Colistin B. These molecules are
identical with Polymyxin B with the exception of the substitution of
a D-phenylalanine by d-Leucine.
Bacitracin is a bactericidal antibiotic active only against gram-positive
organisms.
 A unit of the antibiotic is equivalent to 26 micro-gram of the
USP standard.


43. PHARMACOKINETICS:
 Polymyxin B after IM administration, F(%) = 90.4
 Colistin Lipophilic nature.
 Toxicity: Polymyxin B and Colistin are toxic to the
kidneys: this may be due to their surfactant action
on renal tubular cells, which is similar to their
antibacterial action. Colistin can induce severe
shock in its sulphate form especially in broilers
and ducks. After repeated injections, ascites can
be observed.
 Comments: Synergic bactericidal action when
Colistin is combined with Spectinomycin.

44. SULFONAMIDES
 Tetrahydrofolic acid (THF) is a coenzyme in the
synthesis of purine bases and thymidine. These are
constituents of DNA and RNA and are required for cell
growth and replication. Lack of THF leads to inhibition
of cell proliferation.
 Formation of THF from dihydrofolate (DHF) is
catalyzed by the enzyme dihydrofolate reductase.
DHF is made from folic acid, a vitamin that cannot be
synthesized in the body but must be taken up from
exogenous sources. Most bacteria do not have a
requirement for folate, because they are capable of
synthesizing it - more precisely DHF—from
precursors. Selective interference with bacterial
biosynthesis of THF can be achieved with
sulfonamides and trimethoprim.

45. MECHANISM OF ACTION:
 Sulfonamides possess bacteriostatic activity against
a broad spectrum of pathogens. These are produced
by chemical synthesis, they structurally resemble Para
amino benzoic acid (PABA), a precursor in bacterial
DHF synthesis. As false substrates, sulfonamides
competitively inhibit utilization of PABA, and
hence DHF synthesis. Because most bacteria cant take
up exogenous folate, they are depleted of DHF.
 Trimethoprim: It is a pyrimidine derivative used in
combination with sulfonamides for enhanced
antibacterial activity. Inhibits bacterial DHF reductase. It
has bacteriostatic activity against a broad spectrum of
pathogens. The antibacterial spectrum of TMP is
similar to that of sulfonamides, however, TMP is 20- to
50-fold more potent.

46. INDICATIONS:
Gram-positive and gram-negative organisms
as: Staphylococcus spp., Streptococcus spp.,
Pasteurella, Salmonella and E.coli.

47. METABOLISM: TOXICITY:
 The sulfa drugs are acetylated, primarily in the
liver. The product is devoid of antimicrobial
activity but retains the toxic potential to
precipitate at neutral or acidic pH. This causes
crystalluria and, therefore, potential damage to
the kidney.
 Suppression of bone marrow activity with
resultant anemia. It can cause decrease in egg
shell thickness, soft-shelled eggs as well
as rough surface.
 Drug-Drug Interactions: Urine alkalinization
increases the urinary excretion of sulfonamides

48. AMPHENICOLS
 Description & Mechanism of action:
Chloramphenicol, thiamphenicol, and
Florfenicol are broad-spectrum antibacterial,
bacteriostatic with closely related chemical
structures, recently termed Amphenicols.
 Potent antibacterial agents acting through
interaction with ribosomes to inhibit
organisms from synthesizing proteins. These
compounds inhibit peptidyl transferase
activity and affect microbial protein synthesis.

49. ORIGIN & DOSAGE:
 Chloramphenicol, Streptomyces venezuelae
 Thiamphenicol analogue, Synthetic CPC
 Florfenicol A fluorinated derivative
of thiamphenicol
 Chickens:
 Florfenicol 30 mg/kg bw
 Thiamphenicol 1000 mg/kg feed

50. DRUG-DRUG INTERACTIONS
 Toxicity:
 The p-nitro group of Chloramphenicol is
responsible for serious bone marrow toxicity
and dose-independent irreversible aplastic
anemia in humans. For this reason, the use of
Chloramphenicol in food-producing animals
has been banned.