Definition of Antibiotic –

An antibiotic is a natural substance or derivative of a natural substance, which if taken in small doses, will either kill or prevent the growth of a microorganism, but will not seriously harm the person taking it.

Prescription of Antibiotic(s)-

Many of the infections are viral and self limiting. So, antibiotic for infection is not all time essential. Therefore, while prescribing antibiotic(s) you should follow the “General principles of antibiotic prescribing” given here:

*Prescribe antibiotics only for bacterial infections where-

Symptoms of the disease are severe or significant
The infection is not resolving itself
There is a high chance of arising complications

* Choose the most appropriate antibiotic on the basis of the identification of the microorganism causing the infection.
* Provide prescription of antibiotic(s) with as narrow a range of effectiveness as possible
* Reserve broad spectrum antibiotics for indicated conditions only
* Prescribe a dosage to cure the infection, but use the antibiotic for the shortest possible time which will effect a cure.

Here a tableis given for the practicing doctors, which contains some common Infections, their causative organisms & the antibiotics (according to chronology of efficacy) for those infections.

(Note: For Immunosuppressed patients and those who had splenectomy the choice of antibiotics are a combination of Aminoglycoside with an antipseudomonal Penicillin or Cephalosporin).

Table : Some Infections, their causative microorganisms & the antibiotics (according to chronology of efficacy) for those infections-

Infections	Microorganisms	Antibiotics(according to chronology of efficacy)
Bone infection
Acute osteomyelitis	Staphylococcus, Streptococcus,Escherichia coli,Proteus spp, P aeruginosa.	Cefotaxime,Ampicillin,Amoxicillin, Cephalexin, Cephaloridine, Flucloxacillin plus Fusidic acid,Gentamicin, Kanamycin,Clindamycin.
Chronic osteomyelitis	Staphylococcus, Streptococcus,Escherichia coli,Proteus spp.	Ampicillin,Amoxicilliin,Cephalexin, Flucloxacillin, Cephaloridine, Gentamicin, Kanamycin, Clindamycin.
Fungal Infection of Bone	Aspergillus, Cryptococcus, Histoplasma etc.	Nystatin,Amphotericin B,Fluconazole, Ketoconazole
Septic arthritis	Streptococci, Staphylococcus aureus, Enterobacteriaceae.	Cefotaxime.
Central Nervous System
Bacterial meningitis	Neisseria eningitides, Streptococcus pneumoniae,Listeria monocytogenes, Haemophilus influenzae	For Newborns: Ampicillin + Cefotaxime, Ampicillin +Gentamicin.For patients having age of 2 months-60 years: Ceftriaxone/ Cefotaxime with or without Vancomycin, Meropenem with or without Vancomycin.
Fungal meningitis	Cryptococcus	Amphotericin plus Flucytosine
Viral meningo-encephalitis	Herpes simplex	Aciclovir.
Ear infection		Antibiotic for Ear infection
Acute Otitis Externa	Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, polymicrobial infections	Clioquinol + flumethasone Ear Dropor Dexamethasone + framycetin + gramicidinEarDrop or Ciprofloxacin + hydrocortisone Ear Drop, Oral flucloxacillin (If there is spreading cellulites).
Acute Otitis Media	Respiratory viruses, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis	Amoxicillin, Azithromycin or Clarithromycin or Erythromycin, Cefuroxime, Cefpodoxime, Amoxicillin with Clavulanate, Clindamycin, Ceftriaxone.
Endocarditis	Acute Native Valve Endocarditis (NVE) -Staphylococcus aureus and group B streptococci. Subacute Native Valve Endocarditis (NVE)- Alpha-hemolytic streptococci or enterococci. Early Prosthetic valve Endocarditis (PVE)- Coagulase-negative staphylococci, gram-negative bacilli, and Candida species. Late Prosthetic valve Endocarditis (PVE)- Staphylococci, alpha-hemolytic streptococci, and enterococci. Intravenous Drug Abuse (IVDA) Endocarditis- S aureus. Pacemaker IE- Staphylococci (both coagulase-negative and coagulase-positive). Nosocomial IE (NIE)- S aureus. Enterococci.	Antibiotic for Endocarditis Penicillin G or Ampicillin + Gentamicin, IV Vancomycin+ Gentamicin.
Eye infection		Antibiotic for Eye infection
Conjunctivitis(Infectious)	Viruses, Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Chlamydia trachomatis or Neisseria gonorrhoeae	Antibiotic for Conjunctivitis Topical Chloramphenicol, Topical Fusidic acid or topical Framycetin.
Gall bladder
Acute cholecystitis	Coliforms	Cefuroxime plus Metronidazole, Amoxicillin with Clavulanate, Ciprofloxacin plus Metronidazole.
Gastrointestinal System
Campylobacteriosis	Campylobacter jejuni	Azithromycin or Clarithromycin or Erythromycin, Ciprofloxacin.
Clostridium difficile colitis	Clostridium difficile	Metronidazole, IV Vancomycin (hospital treatment).
Giardiasis	Giardia lamblia	Ornidazole or Metronidazole
Salmonellosis	Salmonella enteritidis, Salmonella typhimurium	Ciprofloxacin,Co-trimoxazole.
Travellers’ diarrhoea	Escherichia coli, Campylobacter jejuni, Salmonella and Shigella species	Ciprofloxacin, Azithromycin.
Genito- Urinary system
Acute non-specific urethritis	Ureaplasma urealyticum, Mycoplasma genitalium, Trichomonas vaginalis	Azithromycin plus Ceftriaxone , Doxycycline plus Ceftriaxone, Azithromycin plus Cefixime or Ciprofloxacin, Ofloxacin.
Acute prostatitis	Escherichia coli, Proteus species, Klebsiella pneumoniae, Chlamydia trachomatis.	Trimethoprim plus Doxycycline,Ciprofloxacin.
Acute pyelonephritis	Escherichia coli, Proteus, Pseudomonas, Staphylococcus aureus, and Enterococcus faecalis (formerly Streptococcus faecalis)	For ambulatory patients: Fluroquinolones: Ciprofloxacin or Levofloxacin or Gatifloxacin or Norfloxacin, 1^st generation Cephalosporins (Cephradine,Cephalexin etc), Amoxycillin with Clavulanic acid, Co-trimoxazole.For hospitalized patients: Fluroquinolones: Levofloxacin or Gatifloxacin, Ampicillin/Sulbactam + Gentamycin, Imipenem/Meropenem.
Bacterial vaginosis	Gardnerella vaginalis, Bacteroides, Peptostreptococci, Mobilunculus	Antibiotic for Bacterial vaginosisMetronidazole or Ornidazole or Secnidazole.
Cervicitis	Chlamydia trachomatis, Neisseria gonorrhoeae, Ureaplasma urealyticum, Mycoplasma genitalium, Trichomonas vaginalis	Azithromycin plus Ceftriaxone , Doxycycline plus Ceftriaxone, Azithromycin plus Cefixime or Ciprofloxacin, Ofloxacin.
Chlamydia	Chlamydia trachomatis	Antibiotic for ChlamydiaAzithromycin,Doxycyclineor Amoxicillin.
Cystitis	Escherichia coli, Staphylococcus saprophyticus, Proteus sp., Klebsiella sp., Enterococcus sp.	Antibiotic for CystitisFluroquinolones: Ciprofloxacin or Levofloxacin or Gatifloxacin or Norfloxacin, Trimethoprim/ Sulfamethoxazole, Nitrofurantoin, 1^st generation Cephalosporins (Cephradine,Cephalexin etc),
Epidiymo-orchitis	Mainly due to Chlamydia trachomatis or Neisseria gonorrhoeae. Also due to E. coli, Bacteroides species, Gardnerella vaginalis, Mycoplasma hominis, Ureaplasma urealyticum, Trichomonas vaginalis, Streptococcus agalactiae	If STI is suspected:Ceftriaxone and Azithromycin, Ciprofloxacin.If UTI is suspected: Amoxicillin clavulanate or Ciprofloxacin.
Gonorrhoea	Neisseria gonorrhoeae	Antibiotic for GonorrhoeaCeftriaxone or cefixime and Azithromycin, Cefotaxime, Cefpodoxime, Cefuroxime, Ciprofloxacin.
Lower UTI	Escherichia coli Staphylococcus saprophyticus Proteus mirabilis Klebsiella pneumoniae	Newborn<2 weeks: Ampicillin + Gentamycin.Newborn 2weeks-2months: Ampicillin+ Cefotaxime.Children>2months:For ambulatory Children : Cephalexin, Co-trimoxazole,Cefixime,Nitrofurantoin. For hospitalized Children : Cefotaxime, Ceftriaxone. For adults: Ciprofloxacin or Levofloxacin, 1^st generation Cephalosporins (Cephradine,Cephalexin etc), Amoxycillin with Clavulanic acid, Co-trimoxazole.
Pelvic inflammatory disease	Chlamydia trachomatis, Neisseria gonorrhoeae and others	For ambulatory patients: Ceftriaxoneand Doxycycline and Metronidazole, Ofloxacin and Levofloxacin and Metronidazole, Azithromycin.For hospitalized patients: Cefoxitin plus Doxycycline, Clindamycin plus Gentamicin plus Doxycycline, Ofloxacjn plus Metronidazole, Ciprofloxacin and Doxycycline and Metronidazole, Azithromycin and Metronidazole.
Syphilis	Treponema pallidium	Antibiotic for Syphilis Benzathine penicillin or Procaine penicillin, Ceftriaxone, Tetracycline or Doxycycline.
Trichomoniasis	Trichomonas vaginalis	Metronidazole or Ornidazole or Secnidazole.
Vulvovaginal Candidiasis	Candida albicans	Fluconazole, Nystatin, Terconazole, Clotrimazole, or Miconazole.
Intra-abdominal Infections & Peritonitis	E. coli, Enterococci, Klebsiella species,Bacteroides, Peptococcus, Fusobacterium and Clostridium species, staphylococci, P. aeruginosa, Candida species, Pneumococcal and streptococcal species,Listeria monocytogenes, Campylobacter coli, and Aeromonas species.	Ampicillin/Sulbactam with or without Aminoglycoside,Cefotetan/Cefoxitin with or without Aminoglycoside,3^rd generation Cephalosporins(Ceftriaxone,Cefotaxime) plus Metronidazole/Clindamycin with or without Aminoglycoside, Ciprofloxacin plus Metronidazole/Clindamycin, Imipenem/Meropenem with or without Aminoglycoside.
Nose
Acute Sinusitis	Respiratory viruses, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, anaerobic bacteria	Amoxycillin or Amoxycillin with Clavulanic acid, Ciprofloxacin or Levofloxacin, Azithromycin, Doxycycline, Co-trimoxazole, Cefaclor.
Respiratory System
Acute exacerbation of chronic bronchitis or COPD	Respiratory viruses, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis	Azithromycin, Levofloxacin, Gatifloxacin, Amoxicillin or Amoxycillin with Clavulanic acid, Doxycycline, 2^nd or 3^rd generation Cephalosporins(Cefixime,Cefpodoxime, Cefaclor), Co-trimoxazole
Aspiration pneumonia	Community-acquired aspiration pneumonia- Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Enterobacteriaceae.Hospital-acquired aspiration pneumonia- Gram-negative organisms including Pseudomonas aeruginosa, Staphylococci.	Coamoxiclav or Amoxicillin+Metronidazole
Atypical or Legionella likey	Legionella pneumophila,Chlamydia pneumoniae, Chlamydia psittaci,Coxiella burnetii,Francisella tularensis,Mycoplasma pneumoniae, Fungus, Protozoa,Virus.	Erythromycin or Tetracycline
Antibiotic for Bronchitis	Acute bronchitis-Mycoplasma pneumoniae and Chlamydia trachomatis.Virus.Chronic bronchitis-Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Virus.	Amoxicillin, Oxytetracycline or Doxycycline.
Community acquired pneumonia (In adult)	Respiratory viruses, Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydophilia pneumonia, Legionella pneumophila, Staphylococcus aureus	For ambulatory patients: Azithromycin or Clarithromycin, Doxycycline, Levofloxacin or Gatifloxacin, Amoxycillin or Amoxycillin with Clavulanic acid, 2^nd generation Cephalosporins(Cefuroxime axetil,Cefpodoxime proxetil, Cefdinir,)For hospitalized patients: Ceftriaxone or Cefotaxime with or without Azithromycin or Clarithromycin, Levofloxacin or Gatifloxacin, Cefuroxime axetil with or without Azithromycin or Clarithromycin.
Community acquired pneumonia (In child)	Respiratory viruses, Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae	Amoxycillin or Amoxycillin with Clavulanic acid, Erythromycin
Hospital acquired pneumonia/Post operative	P. aeruginosa, A.baumanii, Methicillin-resistant S. aureus [MRSA], Stenotrophomonas maltophilia, S. aureus, Haemophilus influenzae, and Streptococcus pneumoniae.	Ceftazidime/Ciprofloxacin+Metronidazole, IV Gentamicin and Ticarcillin with Clavulanic acid.
Pertussis	Bordetella pertussis	Antibiotic for PertussisErythromycin.
Uncomplicated Chest Infection	Respiratory viruses, Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus.	Amoxicillin, Erythromycin.
Septicaemia and Septic Shock	Septic Shockdue to lower respiratory tract infection by- Streptococcus pneumoniae,Klebsiella pneumoniae,Staphylococcus aureus,Escherichia coli,Legionella species,Haemophilus species,Anaerobes,Gram-negative bacteria,Fungi.Septic Shockdue to urinary tract infection by- E coli,Proteus species,Klebsiella species,Pseudomonas species,Enterobacterspecies,Serratia species.Septic Shockdue to soft tissue infection by- S aureus,Staphylococcus epidermidis,Streptococci,Clostridia,Gram-negative bacteria,Anaerobes.Septic Shockdue to GI tract infection by- E coli,Streptococcus faecalis,Bacteroides fragilis,Acinetobacter species,Pseudomonas species,Enterobacter species,Salmonella species. Septic Shockdue to reproductive system infection by- Neisseria gonorrhoeae,Gram-negative bacteria, Streptococci, Anaerobes. Septic Shockdue to foreign body infection by- S aureus, S epidermidis, and fungi / yeasts (eg, Candida species). Septic Shockdue to miscellaneous infection by- Neisseria meningitides.	Antibiotic for Septicaemia and Septic ShockFor Neonates: Ampicillin plus Cefotaxime, Ampicillin plus Ceftriaxone, Ampicillin plus Genatamicin.For Children: 3^rd generation Cephalosporins(Ceftriaxone,Cefotaxime).For Adults: 3^rd or 4^th generation Cephalosporins(Ceftriaxone,Cefotaxime, Ceftizoxime,Cefepime), Piperacillin/Tazobactam, Imipenem/Meropenem, Vancomycin with Aminoglycoside. ;
Skin & Soft Tissue Infections
Bites and clenched fist infections	Polymicrobial infection, Pasteurella multocida, Capnocytophaga canimorsus (bites by cat or dog), Eikenella corrodens (fist injury), Staphylococcus aureus, Streptococci and anaerobes	Amoxycillin or Amoxycillin with Clavulanic acid, Clindamycin/Metronidazole plus Doxycycline or Co-trimoxazole.
Boils	Staphylococcus aureus	Antibiotic for BoilsFlucloxacillin, Cephalosporins (Cephradine, Cephalexin, Cefazolin etc).
Cellulitis	Group A streptococci, Staphylococcus aureus.	Antibiotic for CellulitisFor ambulatory patients: Amoxycillin with Clavulanic acid, Flucloxacillin, Azithromycin, 1^st generation Cephalosporins (Cephradine,Cephalexin etc), Aminopenicillins or Quinolones.For hospitalized patients: Imipenem/Meropenem, IV Cephalosporins (Ceftazidime, Ceftriaxone), Fluroquinolone + Clindamycin/ Metronidazole.
Diabetic Foot Infections	Gram-positive organisms include Enterococcus faecalis, S aureus(specially Methicillin-resistant S aureus (MRSA), S epidermidis,and groupB streptococci.Gram-negative organisms include Proteus species, E coli, Klebsiella species, and Pseudomonas species.Anaerobesinclude Peptococcus species and Bacteroides fragilis	Mild infection: Amoxycillin with Clavulanic acid, Cephalosporins (Cephalexin, Cephradine, Cefazolin etc) plus Clindamycin/Metronidazole,Severe infection: Ampicillin/Sulbactam, Cefotetan/Cefoxitin, Fluroquinolone + Clindamycin/ Metronidazole, Imipenem/Meropenem. IV Vancomycin (If caused by MRSA ).
Erysipelas	Streptococcus pyogenes.	Phenoxymethylpenicillin, Ciprofloxacin plus Clindamycin.
Foot infections	S. aureus, S. epidermidis, and Streptococcus sp.	First-generation Cephalosporins, Clindamycin (for patients allergic to Penicillin), Amoxicillin and Cavulanate, Levofloxacin.
Impetigo	Streptococcus pyogenes, Staphylococcus aureus	Fusidic acid cream, Flucloxacillin.
Mastitis	Staphylococcus aureus for lactating women, anaerobes for non-lactating women or men	Antibiotic for Mastitis Flucloxacillin,Cephalosporins (Cephalexin, Cefazolin etc), Amoxycillin with Clavulanic acid.
Necrotizing fasciitis	Bacteroides species, staphylococci, and enterococci, Aerobic streptococci, E coli and Proteus species	Piperacillin and Tazobactam,Ticarcillin and Clavulanate, Ceftazidime and Clindamycin.
Severe limb- threatening foot infections	S. aureus, S. epidermidis, and Streptococcus sp.	Ampicillin and Sulbactam, Ticarcillin and Clavulanate or Piperacillin and Tazobactam. IV Clindamycin in combination with oral Ciprofloxacin (for patients allergic to Penicillin), Levofloxacin or Gatifloxacin, Aminoglycoside should be added if wounds are suspected of having very aggressive gram-negative organisms.
Throat
Acute Epiglottitis	H. influenzae	Cefotaxime.
Pharyngitis	Respiratory viruses, Streptococcus pyogenes	Phenoxymethylpenicillin, Azithromycin or Clarithromycin or Erythromycin,1^st or 2^nd generation Cephalosporin (Cefuroxime axetil,Cefpodoxime proxetil, Cefdinir), Clindamycin.
Quinsy	Beta haemolytic Streptococci, Anaerobes of mouth cavity.	Phenoxymethylpenicillin with Metronidazole.
Tonsillitis	Streptococci pneumoniae (commonest), Staphylococcus, Pneumococcus, H. Influenzae,Diphtheroids, Viral.	Antibiotic for TonsillitisPenicillin V
Vincent’s Angina	Anaerobes of mouth cavity	Phenoxymethylpenicillin with Metronidazole.
Wound Infections
Abdominal and Pelvic wound infection	Anaerobic streptococci, E. coli, Klebsiella, Proteus, Bacteroides species, Staphylococcus aureus, Pseudornonas and the Group B haemolytic streptococci.	Metronidazole with 2nd or 3rd generation Cephalosporin or Benzyl Penicillin & Genatmycin.
Burn wounds	P aeruginosa, S aureus, Escherichia coli, Klebsiella and Enterococcus species	Piperacillin-tazobactam, Imipenem, Meropenem, Ceftazidime or Piperacillin with Gentamicin, Oxacillin, Cefuroxime, Cefepime, Flucloxacillin, Ciprofloxacin, Levofloxacin, Trimethoprim + Sulfamethoxazole.
Crush injuries	P aeruginosa, S aureus, Escherichia coli, Klebsiella and Enterococcus species,anaerobic organisms	Piperacillin-tazobactam, Imipenem, Meropenem, Ceftazidime or Piperacillin with Gentamicin, Oxacillin, Cefuroxime, Cefepime, Flucloxacillin,Ciprofloxacin, Levofloxacin, Trimethoprim + Sulfamethoxazole.
Gas gangrene	Clostridium perfringens & other species of Clostridium	Benzyl Penicillin,Metronidazole,Chloramphenicol (for patients allergic to Penicillin).
Infection at the site of amputation	Clostridium perfringens,coliforms, anaerobes,gram positive bacteria.	Amoxycillin with Clavulanic acid,Benzyl Penicillin,Metronidazole.
Penetrating/Puncture wounds	S aureus, beta-hemolytic streptococci, and various anaerobic bacteria,Pseudomonas aeruginosa,	Flucloxacillin, Ciprofloxacin, Levofloxacin, Trimethoprim + Sulfamethoxazole, Piperacillin-tazobactam, Imipenem, Meropenem, Ceftazidime or Piperacillin with Gentamicin, Oxacillin, Cefuroxime, Cefepime.

Medical For All

Infections, their causative microorganisms and the antibiotics

Definition of Antibiotic –

Prescription of Antibiotic(s)-

Table : Some Infections, their causative microorganisms & the antibiotics (according to chronology of efficacy) for those infections-

Bone infection

Central Nervous System

Ear infection

Endocarditis

Acute Native Valve Endocarditis (NVE) -Staphylococcus aureus and group B streptococci.

Subacute Native Valve Endocarditis (NVE)- Alpha-hemolytic streptococci or enterococci.

Eye infection

Gall bladder

Gastrointestinal

System

Genito- Urinary system

Escherichia coli, Proteus, Pseudomonas, Staphylococcus aureus, and Enterococcus faecalis (formerly Streptococcus faecalis)

Intra-abdominal Infections & Peritonitis

Nose

Respiratory

System

Septicaemia and Septic Shock

Skin & Soft Tissue Infections

Piperacillin and Tazobactam,Ticarcillin and Clavulanate, Ceftazidime and Clindamycin.

Throat

Wound Infections

To know the Generic and Trade names of the above mentioned drugs and their available formulations in Bangladesh click here.

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