Antibiotics are also called as antibacterials or anti-microbes, which are the medications used in treatment of various bacterial infections. An antibiotic is an agent that destroys or inhibits the growth of micro-organism, or bacteria, or microbes. Bacteria or microbes are microscopic organisms which causes illness or diseases condition of the host organism (human body) due to infections and inflammatory response.

History of Antibiotics –
In 1877, Louis Pasteur and Robert Koch described antibiotic after observing inhibition of growth of Bacillus Anthracis by an airborne bacillus. Alexander Fleming was the first person who discovered the first natural antibiotic, Penicillin, in 1928. It was Selman Waksman who termed the word antibiotic in the year 1942. Selman Waksman with his collaborators described antibiotic as any substance that is produced or secreted by a microorganism, which acts against the growth of other micro-organisms in higher dilution.

  • How antibiotics work?

  • What is bacterial infection?

  • What are the signs and symptoms of bacterial infection or disease?

  • Transmission of bacterial infection?

  • Classification of Antibiotics

  • When your doctor prescribes antibiotics?

  • Medical uses of antibiotics

  • >What are the drug reactions of antibiotics?
  • What do you mean by antibiotic resistance?

  • What is culture and sensitivity test?

  • Precautionary steps while taking antibiotics

  • Antibiotics – Myths and Facts:

  • Purchasing of antibiotics

Antibiotics are potent medicines that fights bacterial infections or inflammations. It can save lives if used in an appropriate manner. Different types of antibiotics have different action on bacterial cell. The action mechanism of antibiotics is either to kill the micro-organism or stops the bacteria from reproducing.

Usually, our immune system fights bacterial infection. Our body’s natural defense mechanism destroys the bacteria after the invasion of the microbes in the body. Human body has special blood cells called as white blood cells (WBCs), which attacks and destroys harmful microbes. Our immune system fights off the infection even if the symptoms occur. However, there are situations when our immune system fails to fight against the infection. In such cases, you need antibiotics to combat bacterial infection.

The mechanism of antibiotics
There are many different types of antibiotics, which usually works in two ways –

  • Bactericidal – A bactericidal usually intervenes with the bacteria’s cell wall or cell content. It kills or destroys the microbes or bacteria, for example, Penicillin.
  • Bacteriostatic – A bacteriostatic stops microbes or bacteria from reproducing or multiplying.

A bacterial infection is caused by a pathogenic bacteria agent. An infection is the intrusion of microbe or pathogenic bacteria in the host organism’s body or tissue (human). After the invasion, the microbes multiply and release toxins leading to inflammation or infection.

There are different types of pathogenic bacteria agents causing various types of medical conditions, which are diagnosed by the physician followed by appropriate antibiotic management.

The diseases caused by the pathogenic bacteria species have characteristic interactions with the human body.

Conditionally pathogenic – In this condition, pathogenic bacteria are activated due to decreased immunity or major wounds. For example, Streptococcus and Staphylococcus are usually present in the skin or the other areas of the body as a part of normal human flora. They can cause bacterial skin infection, pneumonia and septicemia leading to shock and death.

Intracellular – Intracellular parasites such as Rickettsia, Chlamydophila, etc. grow and multiply within the cells or other organisms. Infections caused by intracellular bacteria are usually asymptomatic.

Target location of the body –
Few bacterial infections are classified on the basis of location in the human body, which are as follows –

  • Inflammation of the meninges (covering brain and spinal cord) – Bacterial Meningitis
  • Infection of lungs – Bacterial Pneumonia
  • Infection of urinary tract – UTI (Urinary tract infection)
  • Inflammation or infection of vagina – Bacterial Vaginosis
  • Inflammation of gastro-intestinal tract – Bacterial gastroenteritis
  • Bacterial skin Infections – Impetigo, Erysipelas (inflammation of deep epidermis) and Cellulitis (inflammation of connective tissue)

List of the diseases with pathogenic species of bacteria –
You should take antibiotics under the strict observation of your physician for proper dosage and schedule.

Following are the list of common diseases caused by various pathogenic bacteria agents with appropriate antibiotic treatment –

  • Bacterial skin infections, septicemia, necrotizing pneumonia, toxic shock syndrome, acute infective endocarditis –
    Pathogenic bacteria – Staphylococcus aureus
    Antibiotic – Vancomycin, Nafcillin, Oxacillin
  • Acute bacterial pneumonia, meningitis, otitis media, sinusitis –
    Pathogenic bacteria – Streptococcus pneumoniae
    Antibiotic – Penicillin, Vancomycin
  • Impetigo, erysipelas, streptococcal pharyngitis, rheumatic fever, necrotizing fasciitis –
    Pathogenic bacteria – Streptococcus pyogenes
    Antibiotic – Penicillin, Macrolides (Azithromycin, Clarithromycin)
  • Pseudomonas infections – Infection of eye, ear, skin, respiratory tract, gastro-intestinal tract, urinary tract, bones and joints, soft tissue, central nervous system –
    Pathogenic bacteria – Pseudomonas aeruginosa
    Antibiotic – Aminoglycosides and Anti-pseudomonal β-lactum
  • Secondary bacterial pneumonia/Whooping cough –
    Pathogenic bacteria – Bordetella Pertusis
    Antibiotics  – Macrolide antibiotics (Erythromycin, Azithromycin)
  • Acute enteritis –
    Pathogenic bacteria – Campylobacter pylori
    Antibiotic – Ciprofloxacin
  • Community-acquired respiratory infection –
    Pathogenic bacteria – Chlamydia pneumoniae
    Antibiotic – Doxycycline, Erythromycin
  • Gas gangrene, anaerobic cellulitis and acute food poisoning –
    Pathogenic bacteria – Clostridium perfringens
    Antibiotic – Penicillin or Doxycycline
  • Diphtheria –
    Pathogenic bacteria – Corynebacterium diphtheria
    Antibiotic – Erythromycin, Penicillin
  • Urinary tract infection, meningitis in infants, diarrhea –
    Pathogenic bacteria – Escherichia coli
    Antibiotic – Cephalosporin, Gentamicin, Co-trimoxazole
  • Bacterial meningitis, pneumonia, bronchitis, URTI (upper respiratory tract infection) –
    Pathogenic bacteria – Haemophilus influenzae
    Antibiotic – Cephalosporin, Ampicillin and sulbactum
  • Peptic ulcers (Gastric ulcer and duodenal ulcer), gastric B-cell lymphoma, gastric cancer –
    Pathogenic bacteria – Helicobacter pylori
    Antibiotic – Tetracycline and Metronidazole
  • Tuberculosis –
    Pathogenic bacteria – Mycobacterium tuberculosis
    Antibiotic – Combination of Rifampicin, Isoniazid, Ethambutol and Pyrazinamide
  • Leprosy (Hansen’s disease)
    Pathogenic bacteria – Mycobacterium leprae
    Antibiotic – Dapsone, Rifampin, or Clofazimine
  • Typhoid fever –
    Pathogenic bacteria – Salmonella typhi
    Antibiotic – Ceftriaxone, Fluoroquinolones (Cephalosporins)
  • Bacillary dysentery –
    Pathogenic bacteria – Shigella sonnei
    Antibiotic – Ciprofloxacin, Azithromycin
  • Cholera –
    Pathogenic bacteria – Vibrio cholera
    Antibiotic – Doxycycline
  • Syphilis –
    Pathogenic bacteria – Treponema pallidum
    Antibiotic – Penicillin, Erythromycin, or Tetracycline
  • Leptospirosis –
    Pathogenic bacteria – Leptospira interrogans
    Antibiotic – Penicillin, Tetracycline (Doxycycline)
  • Bubonic and pneumonic plague –
    Pathogenic bacteria – Yersinia pestis
    Antibiotic – Streptomycin, Gentamicin, Tetracycline
  • Brucellosis –
    Pathogenic bacteria – Brucella abortus
    Antibiotic – Doxycycline, Streptomycin
  • Tetanus –
    Pathogenic bacteria – Clostridium tetani
    Tetanus immune globulin, sedation and mechanical ventilation

These are few bacterial infections, which are treated by using broad spectrum antibiotics by mouth or by intravenous/intramuscular administration. The above mentioned diseases, pathogenic bacteria and antibiotics are just for general reference. If you are suffering from any of the above bacterial infections, you should immediately consult your physician for appropriate antibiotic management. Self-medication is not advisable in case of any bacterial infection.

The signs and symptoms of bacterial infections of diseases depends on the type of pathogenic bacteria agent, the part of the human body, and other factors such as medical history and patient’s age and susceptibility. There are certain signs and symptoms that indicate bacterial infections or diseases.

Most common signs and symptoms of bacterial infection

  • Fever – Fever is a common symptom of bacterial infection. When your body fight with the infection, your temperature levels are on the higher side. Low-grade fever i.e. temperature less than 102O F may occur. One may experience high-grade fever i.e. more than 102O F, associated with severe chills or rigors in serious bacterial infection.
  • Headache – Headache is usually low grade. In severe infections the pain is annoying with throbbing headache associated with burning in eyes.
  • Fatigue – Generalized weakness is a common symptom in any kind of infection. You may feel weak and sick due to low immune status.
  • Loss of appetite – Anorexia or loss of appetite is caused due to infection. One may experience anorexia from bitter taste and indigestion while suffering from bacterial infection. Loss of appetite occurs mainly due to vomiting, stomach pain, digestion problem and bitter taste in mouth.
  • Weight loss – In severe bacterial infections, one may experience weight loss due to loss of appetite. Insufficient intake of food, vitamins and minerals can lead to weight loss, sometimes associated with muscle wasting.
  • Pains or aches – You may experience pain all over the body including muscles and joints, which affects your body movements leading to stiffness and pain on movement.
  • Swelling of lymph nodes – In bacterial infection, your physician may feel your swollen lymph nodes, especially under the jaw line, under the arms, base of the skull, neck region and other areas of the body.
  • Localized signs and symptoms – The classical signs and symptoms of bacterial infection are localized pain, redness, tenderness, swelling and heat. For example, in case of gastro-intestinal infections, one may experience stomach or abdominal pain or upset associated with vomiting and diarrhea. In case of severe bacterial infection, you may suffer from black, bloody or tarry stools with signs of dehydration and/or vomiting of blood.
  • Bacterial skin infection – Abscess, boils and carbuncles are the common signs of bacterial infections on skin. In these conditions, the area of the skin affected becomes red, warm, tender, inflamed with collection of pus in the tissue. In case of big abscess or boils, the pus is drained by incising the wound, and oral antibiotics are prescribed for healing the wound.

Early detection of the signs and symptoms allows you to manage your infection with quick recovery of the health. Many people do not consult their health care specialist for a mild bacterial infection, which goes untreated due to negligence on the part of the patient. If these bacterial infections are not managed on time, they lead to secondary infection with medical complications such as septicemia (followed by shock or death). Your physician will treat your bacterial infection with the help of antibiotics that are suitable for your diseases condition, in the form of tablets or capsules, injections or topical applications.

Bacterial infection can be transmitted from various potential routes; hence some of the infections are communicable or transmissible.

Following are the routes of transmission of bacterial infection –
Fecal-oral transmission – Contaminated water or foodstuffs intake can lead to various bacterial infections such as gastroenteritis, cholera, etc. Pathogenic bacteria agents that are transmitted through fecal-oral routes are Escherichia coli, Entameba histolytica, Tape worms, Vibrio cholera and Giardia.

Droplet contact – Air borne disease are caused due to droplet infection through respiratory route. The infection may enter the body through mouth, nose and eyes from infected person’s cough or sneeze. The common disease caused by this route is Tuberculosis, which is caused by pathogenic bacteria Mycobacterium tuberculosis.

Direct contact transmission – Few infections are caused due to direct contact of the body part, such as impetigo, athlete’s foot, etc.

Sexual transmission – STD (Sexually transmitted disease) also known as venereal disease are caused due to sexual intercourse, wherein certain bacterial agents are transmitted in the process. Syphilis, which is caused due to Treponema pallidum is usually transmitted through sexual contact.

Oral transmission – Few bacterial infections may occur due to oral transmission such as sharing a drinking glass or cigarette, kissing, etc.

Vertical transmission – It is the direct transmission of infection from the mother to the fetus or new-born.

Iatrogenic transmission – It is the infection caused due to infected materials used during surgical procedures or injections.

Vector-borne transmission – In this type of transmission, a vector (organism) transmits infection by carrying the pathogenic agents from one body or host to another body.

The classification of antibiotics are usually done after considering the bactericidal or bacteriostatic action of the drug.

Few classifications of antibiotics –

  • Aminoglycosides –
    The microbes are unable to synthesize proteins that help in growth of bacteria. Aminoglycosides inhibits the synthesis of proteins.
    Indications – Tuberculosis, gonorrhea, E. coli and Klebsiella, etc.
    Few Generic names – Amikacin, Gentamicin, Kanamycin, Neomycin, Streptomycin, etc.
  • Carbapenems –
    It is a bactericidal and inhibits the bacterial cell wall synthesis. It is a broad spectrum antibiotic.
    Indications – Used in both Gram-positive and Gram-negative bacterial infections
    Generic – Meropenem, Imipenem/Cilastatin, Doripenem, etc.
  • Cephalosporins –
    These antibiotics are further classified from first generation cephalosporins to fifth generation cephalosporins. This type of antibiotics breaks the layer of bacterial cell walls.
    Indications – Used in Gram-positive, Gram-negative and pseudomonal infections.
    Generic – Cefadroxil, Cefaclor, Cefazolin, Cefuroxime, Cefoxitin, Fefixime, Cefotaxime, Cefpodoxime, Ceftazidime, Ceftriaxone, Cefepime, etc.
  • Penicillin –
    It breaks the cell wall of bacteria.
    Indications – Streptococcal infection, Lyme disease, Syphilis and other bacterial infections.
    Generic –Penicillin, Amoxicillin, Ampicillin, Piperacillin, etc.
  • Macrolides –
    Inhibits bacterial protein synthesis.
    Indications – Streptococcal infection, Syphilis, Upper and lower respiratory tract infection, etc.
    Generic – Azithromycin, Erythromycin, Clarithromycin, etc.
  • Quinolones –
    Inhibits DNA transcription and replication.
    Indications – Pneumonia, Urinary tract infection, bacterial diarrhea and prostatitis, gonorrhea, etc.
    Generic – Ofloxacin, Ciprofloxacin, Gatifloxacin, Norfloxacin, etc.
  • Sulfonamides –
    Inhibition of folate synthesis by forbidding certain enzymes.
    Indications – Urinary tract infection, eye infections, burns, etc.
    Generic – Sulfadiazine, Sulfamethoxazole, etc.
  • Tetracyclines –
    Inhibits bacterial growth.
    Indications – Syphilis, Chlamydial infection, Mycoplasmal infections, Malaria, etc.
    Generic – Doxycycline, Tetracycline, etc.
  • Oxazolidonones –
    Inhibits bacterial growth. Generic – Linozolid
  • Nitrofurans –
    Indications – Urinary tract infection, Bacterial or protozoal diarrhea or gastro-enteritis.
    Generic – Nitrofurantoin, Furazolidone.
  • Glycopeptides –
    Indications – Used in aerobic and aneorbic Gram-positive bacterial infection.
    Generic – Vancomycin

These are few types of antibiotics that help in managing the bacterial infections. However, there are many other antibiotics, which may be prescribed to you by physician or medical officer at hospital. In case of other chronic infections such as tuberculosis, your physician may prescribe you combinations of various antibiotics with proper dosage schedule.

Your doctor will prescribe antibiotics in case of serious bacterial infections, and in case of few parasitic infections. In case of viral infections, you are not prescribed antibiotics, though the signs and symptoms of the bacterial and viral infection are similar. In such cases, you need antiviral drugs to suffice your viral infection.

If you are suffering from mild bacterial infection, your immune system will clear it without any antibiotics. Few health care providers may give you antibiotics for speedy recovery in case of bronchitis, throat infections, and ear infections caused by bacterial agents. A mild bacterial infection like acne may require oral antibiotics or antibiotic creams or lotions to subside infection.

However, you physician will prescribe you broad spectrum antibiotics in case of serious bacterial infections such as pneumonia, meningitis or septicemia. In such cases, antibiotics play a vital role in saving your life.

Antibiotics are widely used by innumerable physicians to treat various infections. They are usually used to treat the disease condition or to prevent infection.

  • Treatment –
    • Bacterial infection
    • Protozoal infection (metronidazole)
    • Immunomodulation or immunotherapy (Tetracycline in periodontal inflammation, Dapsone in autoimmune disease)
  • Prophylaxis  –
    • Post-surgical management
    • Surgical wounds
    • Dental antibiotic prophylaxis
    • Cancer-related problems such as neutropenia (decrease levels of neutrophils – part of white blood cells)

Mode of administration of antibiotics –
There are different routes of administration of anti-microbial drugs. Your physician will suggest you the mode of administration after considering the severity and type of bacterial infection.

  • Oral antibiotics are taken orally or by mouth
  • Intravenous or intramuscular antibiotics are given in severe bacterial infection, such as systemic infections. Intravenous injections are administered through intravenous drip and intramuscular injections are injected in deep muscles.
  • Topical applications in the form of eye/ear drops, ointments, lotions, creams, etc. are used locally on the affected part.

Many antibiotics have one or the other side effects, which should be treated or managed with help of your physician to avoid health complications.

The most common drug reactions of antibiotics –

  • Diarrhea – Due to antibiotic treatment, the sugar levels in the gut increases that allow bacteria to thrive on it leading to gut infection that is followed by diarrhea.
  • Fungal infections of digestive tract, mouth and vagina
  • Generalized weakness, feeling sick and malaise
  • Nausea and stomach pain

Rare side effects of antibiotics –

  • Cephalosporins – abnormal blood clotting, allergic reactions
  • Trimethoprim – blood disorders
  • Tetracyclines – sensitivity to sunlight, depression of bone growth
  • Erythromycin and Aminoglycosides – deafness, vertigo, kidney damage, jaundice
  • Sulphonamides – kidney stone formation, decreased white blood cells
  • Penicillin – kidney and brain damage

In elder patients, antibiotics may cause severe diarrhea due to inflamed bowels (colitis). A broad spectrum antibiotic such as Clindamycin has this side effect, which is used in most serious infections.

In many cases, pathogenic bacteria fight with the antibiotic that you take and your infection persists. Your physician may term this as an antibiotic resistance. When your infection does not go away even after a proper antibiotic course, your doctor will prescribe you a different antibiotic to tackle your bacterial infection after considering the reports of blood culture or microbial culture of blood.

In case of pus formation (abscess), your doctor will advise culture and sensitivity test for appropriate antibiotic treatment.

Your physician will collect the tissue or the pus from the infected area. The material is then sent for pathological analysis i.e. culture and sensitivity test.

In this test, a laboratory technician will perform few procedures to detect the bacteria and its sensitivity to antibiotics.

Uses of culture and sensitivity test –

  • Identification of pathogenic bacteria agent(s)
  • Determination of pathogenic bacteria sensitivity to antibiotics
    • Sensitivity – The antibiotic kills the bacterial agents. In this test, a particular antibiotic is effective against the infection
    • Intermediate – Few bacterial agents are sensitive or resistant to a particular antibiotic
    • Resistant – A particular antibiotic is ineffective in subsiding the infection or it is unable to kill the pathogenic bacteria

If you’re prescribed antibiotic does not act against pathogenic bacteria, your infection lasts longer and you may require the right antibiotic to kill the bacteria. In case of serious infections, you may require hospitalization to subside your infection. Your physician may prescribe you a single antibiotic or a combination of antibiotics to eliminate you bacterial infection in the form of oral medications or intravenous/intramuscular injections.

In few cases, the resistant pathogenic bacterium remains alive in your body, wherein you will be the carrier of the bacterium, and you could transmit them to your family members or friends. Therefore, you should consult your physician regularly, until your infection is totally eradicated.

One should be careful while undergoing antibiotic management. You should know the indications, risks and benefits, and precautionary measures before and during antibiotic therapy. Usually antibiotics are made from fungi or bacteria to kill other disease causing microbes. Antibiotics such as Penicillin, Tetracycline, Streptomycin, etc. are common antibiotics made from micro-organisms.

Following are the precautionary measures –

  • You should take antibiotics strictly under the supervision of your healthcare practitioner.
  • Antibiotic therapy (course) should be completed as directed by your physician.
  • You should consume antibiotic medicines at the right time and in the right amount.
  • An over dose or wrong dose of antibiotics can lead to other health complications and it also hampers the efficacy of the drug.
  • You should not take antibiotics on empty stomach.
  • You should inform your physician, if you are allergic to any other antibiotic or any other drug before starting up with antibiotic therapy.
  • One should not consume excessive amount of antibiotics, as they may kill the “good bacteria” in the body, which acts as a normal human flora.

Antibiotics are the drugs that are considered as the “one stop cure” for all the infections. Many people pop them for common complaints like cough, sneezes and fever. Undoubtedly, antibiotics are powerful fighters of bacterial infection, but if you use them indiscriminately, then you can actually endanger your health.

Following are few myths and facts about antibiotics –
Myth – Antibiotics can treat all infectious disease.
Fact – Antibiotics can treat only those infections that are caused by bacteria, and not by viruses. Certain parasites and fungi are susceptible to antibiotics, but they are usually treated with anti-parasitic agents and antifungal agents, respectively.

Myth – Antibiotic subside the infection and can be stopped immediately.
Fact – Antibiotic therapy should be taken exactly as directed by the physician. For example, a particular antibiotic is prescribed for five days by your physician; it means the course of antibiotic is for five days. If you fail to do so, your infection may occur again and you may suffer from antibiotic-resistant, which can be serious or difficult to treat again.

Myth – Antibiotic resistance does not exist.
Fact – Pathogenic bacteria agent becoming resistant to antibiotics actually exist. Indiscriminate use of antibiotics or discontinuation of antibiotics before the completion of therapy can lead to re-infection or inappropriate treatment resulting into antibiotic resistant. In this case, the bacterial growth is not affected by antibiotics.

Myth – One can use antibiotics to prevent infection as a precautionary measure (like vaccines).
Fact – No, you cannot take antibiotics as a vaccine or as a precautionary step. Antibiotics should be taken when you are affected with bacterial infections. If you use antibiotics when they are not in need, you are harming your body. You are damaging the ‘good’ bacteria i.e. the natural human flora. Pathogenic bacteria develop resistance to antibiotics leading to more problems. However, few physicians recommend antibiotic prophylaxis in case of gastrointestinal surgeries, dental surgeries, pneumocystis, etc.

Myth – Antibiotics can be used in colds or flu.
Fact – Colds or flu symptoms are caused due to viruses, hence antibiotics are ineffective against colds and flu.

Myth – Antibiotics boosts the immune system to cure infection.
Fact – Antibiotics only kill or retard the growth of bacteria, they do not boost or strengthen the body’s immune system. In fact, it is the immune system that recovers the body from the infection and antibiotics just kill the bacterial agent.

Myth – If you have fever, you should go for antibiotic therapy.
Fact – Generally, fever is a result of inflammatory response between any kind of infection and body’s defense mechanism. Fever can also occur due to viral infection. Hence, antibiotics are not recommended in all the infectious diseases. They are used only in infections caused due to pathogenic bacteria agent.

Myth – The best way to treat infectious diseases is by using combination of antibiotics.
Fact – Combination therapy of antibiotics can lead to antibiotic-resistant and bacteria to multiply. Combination therapy is a common practice, but researchers claim that this practice allows bacteria to multiply, with occurrence of antibiotic-resistant.

Myth – There are no more antibiotics in making and scientists do not have new antibiotics.
Fact – Currently, new types of antibiotics are being tested by scientists. Due to rise in antibiotic-resistant, scientists are looking for new antibiotics to fight against bacterial infections.

One should get an appropriate doctor’s prescription for buying antibiotics. You can purchase antibiotics from direct pharmacy store or from the online pharmacy store by using internet through healthcare websites. One can buy oral and topical-based antibiotics from online drug stores at affordable rates. The healthcare websites take utmost care in packing and shipping your antibiotic medications, thereby maintaining the efficacy and effectiveness of the medicine throughout the process from ordering the product to the delivery.

Few antibiotics such as Doxycycline, Cephalexin, Generic Keflex, Cefdinir, Minoz are available on online medical stores.

One should be careful while undergoing antibiotic therapy. You should complete the antibiotic course prescribed by your physician to subside the bacterial infection. You should strictly follow all the instructions given on the medicine label or leaflet before taking antibiotic tablets.

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