Introduction of Pseudomonas Infection
Gessard first discovered this infection in 1882. Pseudomonas infection is one type of bacterial infection which is caused by Pseudomonas aeruginosa bacterium. Mostly normal people have this infection without knowing. It is mostly found in moist environment such as from soil, plants, animals, and water. It causes serious infection that sometimes produces life threatening conditions. Doctors may find difficulties in treating such conditions because these organisms are resistant to most of the antibiotic drugs.
More than 20 species of pseudomonas are found but, only aeruginosa causes the most common infection. Healthy people may get this infection and people whose immunity are very low may have higher chances of getting this infection. The person gets infected when the bacteria has proper path to enter into the body such as through intravenous lines, urinary catheters, burn injuries, endotracheal tubes, dialysis tubes, etc. The bacteria may be found in hot water tubs and swimming pools, they may cause ear infection or skin rash. Organisms may enter into eyes via non sterile contact lenses leading to severe eye infection. Most commonly, aeruginosa type infection occurs in patients hospitalized for more than 7 days. It is also found in patients with low immunity due to diseases such as AIDS, other respiratory diseases, patients on immunosuppressants, etc. It is associated high mortality rate because treatment is very difficult to resolve this condition.
Signs and Symptoms of Pseudomonas Infection
Symptoms depend upon the location of infection. There are wide varieties of symptoms found with this infection.
- Respiratory Tract - If pseudomonas infects the respiratory tract, it causes pneumonia. Pneumonia means inflammation of the alveoli, which is the functional unit of the lungs. In emergency department, bacteria enters into the respiratory tract through mechanical ventilator tube or endotracheal tube. The characteristic symptoms are chronic cough, hypersecretion of the mucus, high grade fever, weakness, etc.
- Blood Stream - Pseudomonas causes bacteremia, which is the presence of Pseudomonas aeruginosa in blood. Bacteria may enter into blood via surgery, infected respiratory tract or gastro intestinal tract. Sepsis is the most common complication of bacteremia. Sepsis is defined as generalized inflammation of the body. It is a very serious condition and has very high mortality rate. Infection of the blood also spreads the infection to other parts of the body. It is characterized by high pulse rate, low blood pressure and fever. It is mostly evaluated from blood sample culture.
- Heart - Pseudomonas infection causes endocarditis. Heart has three layers. The innermost layer of the heart is known as endocardium. It is defined as inflammation of this layer due to infection. It occurs mostly secondary from other infected sites. Most of the time, it also affects the valves of the heart leading to heart attack. It is characterized by fever, high pulse rate, and abnormal heart sounds.
- Central Nervous System - Brain and spinal cord are covered with specific layers known as meninges. Pseudomonas infection causes inflammation of meninges known as meningitis and brain abscess. Infection may come from external ear, sinus or mastoid process. Fever, headache, confusion, loss of memory are the main features of it.
- Ear - This organism causes otitis externa, a fungal infection of the external ear. It is characterized by pus formation, intense pain and swelling of the inner ear. It is the second most common condition that occurs with pseudomonas infection. Pus discharge and mild fever may accompany this. If it remains untreated it will spread to central nervous system leading to meningitis, abscess and brain nerve palsy.
- Eye - Pseudomonas infects the eye structures such as aqueous humour, cornea, vitreous humour, etc. When this organism infects the eye, it produces some extracellular enzymes which damage the structure of the eye. It may be progressive and very destructive in nature. Damage is irreversible in nature. It is characterized by pain in eyes, which is intense in nature, inflammation, redness in the eye and also visual impairment.
- Bones and Joints - Particular sites such as sternoclavicular joint, pelvis, vertebral column are most commonly involved. Infection of bones and joints occur. Vertebral osteomyelitis is the common complication. Osteomyelitis means bacterial infection of the bones which is characterized by pus formation, pain, restriction in bone growth, destruction of bone, local tenderness, decreased range of motion, puncture wound with pus, and may be a fracture.
- Gastrointestinal Tract - Irritability, nausea, diarrhea, dehydration are the common complications associated with this organism. Abnormal abdominal distension and abdominal pain is also present.
- Urinary Tract - This organism causes infection of the ascending urinary tract. It is initiated by the catheterization or surgery. There are some characteristic features of the Urinary Tract Infections (UTI) such as intense pain in the lower abdominal area, mild fever, burning sensation while urination, irritation in urethra.
Investigations for Diagnosing Pseudomonas
- Complete Blood Count (CBC) shows increase in the number of leucocytes, a type of white blood cells responsible for destroying foreign particles.
- Urine analysis shows presence of pseudomonas in urine culture test if patient has urinary tract infection due to pseudomonas organisms.
- If patient is suffering from pneumonia due to pseudomonas infection, sputum is collected in one bottle and sent for sputum analysis. It shows presence of bacteria.
- Chest-x-ray shows bilateral lung bronchi, segments and lung edema (accumulation of fluid in the base of lung fields). Cavitation may be present.
- Cerebrospinal fluid is evaluated for presence of pseudomonas organisms through lumbar puncture if patient has meningitis. One syringe is inserted through space between subsequent two vertebrae and fluid sample is taken from it and sent for culture examination.
How to Treat Pseudomonas Infection?
Antibiotics are widely used to treat pseudomonas infection.
- Gentamicin is largely used in this type of cases. It can be given intravenously or intra muscularly. Dosage is 1 to 2.5 mg per kg per dose every eight or twelve hours. It acts directly and destroys the bacteria as it reacts with bacterial antigen and disturbs its cell activity and causes death of this organism.
- Piperacillin alters the action of cell wall structure and restricts the biosynthesis of it. It is best used when the organisms have initiated to multiply. It is also given intravenously. Dosage is 3.1 gram iv every 4 or 6 hours.
- Imipenem and Cilastatin are widely used when there is presence of multiple organism infection. It also can be given intravenously. Dosage is 500 to 750 mg every twelve hours. It binds with the specific protein which is present on the surface of the wall of the organism. It alters the structure and restricts the biosynthesis activity of the antigen.
- Aztreonam acts in the same way as above. It can be given intramuscularly or intravenously. Intramuscular route is widely used because drug is well absorbed through this route. Dosage, in moderate to severe cases is 1 to 2 gram every 8 or twelve hours. Dose must not be exceeding 8 gram per day. In moderate to severe cases 2 gram every 6 or 8 hours and should not exceed 8 gram per day.
- Ciprofloxacin has strongest bactericidal activity. It inactivates the activity of the DNA of the organisms. It breaks down the DNA. It restricts the cell multiplication through this way. Dosage in mild to moderate cases is 500 mg every twelve hour orally or 400 mg every twelve hour for ten days intravenously. In severe cases it can be given 750 mg every twelve hour or 400 mg every twelve hour for four weeks.
- Cefepime is only for pseudomonas infection. It is widely used in case of meningitis. It is given intravenously. Dosage 1 to 2 gram intravenously for every 8 or 12 hours for 21 days. Its mechanism of action is also same as above.
- Ceftazidime is also widely used against pseudomonas. It binds with surface protein of the bacteria which is responsible for cell division or growth. By this way, it arrests the growth of bacteria. Dosage is 2 g intravenously every 12 hours.
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