Gram Positive and gram Negative - Essay Example

Introduction It is evident that sample contains various kinds of microorganism belonging to different species, although the disease causing organism pre-dominates other micro flora present in the sample. Identification is based on the kind of Gram reaction shown by the organism. This is the most pragmatic staining also called differential staining performed to categorize microbial population into two groups the Gram positive and Gram negative organisms. The reaction displays the characteristic of the cell wall of the bacterial species. If the bacterial species possess thick peptidoglycan layer it displays Gm +ve differential staining and if the microorganism possess thin or single layer of peptidoglycan then it takes up the counter stain Safranin of the Gram reaction. Thus, G +ve organisms display purple staining whereas the G –ve organisms take up the counter stain and display pink staining. Counter stain Safranin is added to the reaction after washing the Gram stain with alcohol. This step is most imperative as Gram positive organisms possessing thick peptidoglycan retains the stain while Gram negative organisms possessing thin peptidoglycan cell wall becomes colorless and therefore takes up the counter stain when stained with Safranin. It is therefore this staining procedure aids as a diagnostic device in medical as well as research pursuits. Staining also helps in identifying the morphology of the microbial population (Korolik, 2008). "Gram Negative- Klebsiella pneumoniae" Classification Klebsiella pneumoniae belong to Kingdom- Bacteria; Phylum- Proteobacteria; Class- Gamma Proteobacteria; Order- Enterobacteriales; Family- Enterobacteriaceae (Todar). Characteristics- It is a Gram-negative rod. The bacteria does not possess flagella and therefore not motile bacteria. It possess capsule and therefore it is encapsulated. Klebsiella is known to be lactose fermenting organism (Ryan, 2004). Habitat It is present as the natural microflora on the epidermal layers especially skin and oral cavity. It is also present in the intestine. It is also present in soil and around 30% of the species fix nitrogen under anaerobic conditions (Postgate, 1998). Background Klebsiella is becoming the topic of research as it is emerging as an impetrative pathogen in nosocomial infections. Klebsiella possess two different kinds of antigens one on its cell wall and other on its capsule. The O antigen is present as a cell wall component on the lipopolysaccharide (LPS) and possess 9 different kinds. The capsular antigen is known as K antigen and possess as many as 80 different kinds. These antigens are responsible for the virulence of the organism (Podschun, 1998). Clinical implications These virulence factors are responsible for disease called pneumonia. Pneumonia is the disease of lungs and results in inflammation of lungs. This results in necrosis of cells. It then produces thick, blood filled mucous or sputum. The causal organism is Klebsiella pneumoniae. The organism gains access into the lower part of respiratory tract and inhabit there as an oropharyngeal microbial population (Todar). If the immune system of the individual is compromised either due to poor nutrition or some condition of illness then the individual is likely to suffer with pneumonia. It is observed that Klebsiella pneumoniae affects individuals suffering from either diabetes, or display any kind of malignancy or witness liver disease or malfunction or if the individual is alcoholic. It is also reported that individuals with Chronic Obstructive Pulmonary Diseases (COPD) or suffer from renal failure, they also become victim of Klebsiella pneumoniae. Professional hazard in case of paper mill workers is also observed where personnel are likely to become soft targets for Klebsiella pneumoniae (Todar). Hospitalizations could also result in Klebsiella pneumoniae infestation and therefore the organism is becoming a source of nosocomial infections. Under these conditions, Klebsiella pneumoniae causes bronchopneumonia and also bronchitis. The patient may witness abscess of lungs, or cavitations in lungs, pus may get collected in the lung cavities resulting in empyema or pleural empyema, as a result of pneumonia, this are linked with parapneumonic effusions. This is a three phase ailment encompassing (Pothula, 1994). a. exudative phase where accumulation of pus takes place. b. fibrinopurulent stage where lot of pus pockets are being generated. c. the organizing stage which causes entrapment of lung(s) (Pothula, 1994). Pleural adhesion may be generated as a result of all the implications causing elevation in death rate. Klebsiella also affects the urinary tract, causing UTI. It also disrupts the intestinal lining and hence causes diarrhea. It is capable of colonizing in the upper respiratory tract and causes upper respiratory tract infection. It also causes infection of wounds, inflammation of gall bladder causing cholecystitis, as well as infection of bone and bone marrow leading to osteomyelitis. The most dreaded infection caused by Klebsiella pneumoniae is the inflammation of meninges leading to meningitis, it travels the blood stream leading to septicemia (Todar). The prevalence of Klebsiella pneumoniae in the invasive device or support equipments or catheters, not only contaminates the device but also position patients at an enhanced risk for Klebsiella infection. Thus sepsis as well as septic shock enables the bacteria to gain entry into the blood (Todar). "Gram Positive- Staphylococcus aureus" Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA) colonization, results in severe infections in humans. It is examined that Methicillin-resistant Staphylococcus aureus (MRSA) is a widespread basis of illness in society and hospital surroundings. The severity is due to its multi-drug resistant nature. It is therefore also known as multidrug resistant Staphylococcus aureus, as it is the strain that has developed resistance to beta-lactam as well as cephalosporin group of antibiotics. It is a nuisance in hospital for the patients with open wounds or on invasive devices. It is bothersome for immunocompromised patients. Signs and Symptoms of MRSA- In most of the cases skin infections leads to MRSA: 1. Cellulitis: Infection of the skin or skin tissues, initiated as small red bump. Boils: They are generally pus-filled and occur due to inflammation or infection of the hair follicles. 2. Abscess: It occurs due to accumulation of pus either in the skin epidermal cells or in the underlying tissues of the skin. 3. Sty: It occurs due to the infection of oil gland present on the eye lids. 4. Carbuncles: It is more severe kind of infection, a condition serious than the abscess. 5. Impetigo: In such condition pus-filled blisters occur. 6. Rash: Skin demarcates red colored patches. MRSA gains entry into the body through these lesions on the skin and can spread to other organs too. Once it gains entry into the internal organs the condition may worsen and symptoms like, fever, chills, reduction in blood pressure, pain in joints could be witnessed, further, headaches, shortness of breath may result. Under grave conditions rashes appear all through the body and a medical emergency occurs. The condition may lead to endocarditis, necrotizing fasciitis, sepsis, osteomyelitis all these conditions may turn out to be fatal. Transmission of MRSA 1. Direct contact with the patient: Physical contact with the patient or the person who is victim of MRSA or a carrier, those who are not infected but harbor the organism. 2. Indirect contact: Contacting doors, windows, latches, handles, floors, taps, sinks, towels that was once touched by the MRSA-infected patient or a carrier of MRSA. 3. People with normal skin are at lesser risk then those with open wounds, cuts or abrasions or psoriasis. 4. Carelessness towards the skin imperfections may also result in causing invasion of MRSA. 5. Lung infected patients such as cases of pneumonia can transmit MRSA by means of airborne droplets. 6. Healthcare workers may also serve as a vector for the transmission of MRSA. Diagnosis of the Disease Sample from skin, either pus from wound or blood, urine or from the biopsy tissue is examined microbiologically. The sample is cultured for S aureus. On isolation of the strain it is tested for its antibiotic sensitivity/ resistance. Growth of the organism in the presence of antibiotic Methicillin, indicates the resistance of S aureus for antibiotic and the individual is diagnosed as MRSA positive. The test confirms the infection due to MRSA and infection is not due to any other means viz. Insect/ spider bite or any other incidence such as skin changes as in Lyme disease. In recent days samples can be observed in PCR (MRSA Infection). Prevention of MRSA Infection 1. No direct contact with the patient, especially skin and clothing or any other item being touched or used by the patient or carrier. 2. Application of antiseptic cream or covering the wound with first aid dressing material could prevent wounds from contracting the infection. 3. Adopting and practicing good hygiene reduces the chances of getting infection. 4. Frequent hand washing habit could also prevent chances of infection. 5. Clothes should be washed properly and if possible should be sterilized. 6. Constant screening of the patients when administered to the hospital may reduce the chances of hospital acquired MRSA. 7. Constant surface sanitization may prevent the spread of MRSA. 8. Routine and regular use of surgical respirator may prevent the spread of MRSA. 9. Adoption of appropriate method for the disposal of hospital waste may also prevent spread of MRSA. 10. Isolation of MRSA victims may minimize the MRSA spread incidence. 11. Check on the utilization and prescription of antibiotics. Treatment It is evident that, apart from emerging cause of skin and soft tissue infections, S. aureus, including MRSA, also represents a significant proportion of invasive infections, including bacteremia. CA-MRSA and HA-MRSA are known to be highly resistant to anti-staphylococcal beta-lactam antibiotics. Vancomycin has emerged as the drug of choice for the CA-MRSA. Although HA-MRSA shows much resistance towards the antibiotics including Vancomycin. In the recent years, linezolid and daptomycin are found to be effective against both the groups, CA-MRSA and HA-MRSA. To treat MRSA infections, glycopeptides antibiotics such as Vancomycin and teicoplanin. It is observed that Teicoplanin has similar spectrum as Vancomycin but possess longer half-life than Vancomycin. It is recommended that these antibiotics must be administered intravenously for rapid action as well as to check systemic infections (Janknegt,1997). Recent studies display the fact that honey could be used to combat MRSA because of its high osmotic concentration and hypertonic nature. Prognosis Prognosis of MRSA infection depends on the intensity of the infection. It is reported that MRSA associated with pneumonia or any other lung infection and blood poisoning display high death rate. It is observed that individuals possessing good health and high immunity recover and the recovery percentage is ~100% in case of good and sound health as well as immunity. It is also believed and postulated that an individual could remain a carrier for as long as 30 months. In case of immunocompromised individual, or as soon as the body immunity is lowered due to physiological condition or due to contraction of some disease or ailment, recurrence of the disease may occur or the individuals may get victimized of MRSA (MRSA infection-1). References Janknegt, R. "The treatment of staphylococcal infections with special reference to pharmacokinetic, pharmacodynamic, and pharmacoeconomic considerations". Pharmacy world & science : PWS 19 (3): 133–41, 1997. Korolik, V., Beacham, I.R. Microbiology study guide, 2007HSC Microbiology, Griffith University, Gold Coast, Australia. 2008. "MRSA Infection". (Online). 11 Mar 2012. . "MRSA Infection-1". (Online). 11 Mar 2012. . Podschun, R., Ullman, U. "Klebsiella spp. as Nosocomial Pathogens: Epidemiology, Taxonomy, Typing Methods, and Pathogenicity Factors". Clinical Microbiology Reviews, 11 (4), 589–603. 1998. Postgate, J. Nitrogen fixation. 3rd ed. Publisher: Cambridge University Press. 1998. Pothula, V., Krellenstein, D. J. "Early aggressive surgical management of parapneumonic empyemas". Chest, 105 (3), 832–6. 1994. Ryan, K. J., Ray, C. G. "Sherris Medical Microbiology", 4th ed. Publisher: McGraw Hill. 2004. Todar, K. Todars Online Textbook of Bacteriology. (Online). 11 Mar 2012. http://www.textbookofbacteriology.net. Read More