Medical Microbiology case study - Essay Example

Medical Microbiology Case Study All about the case study The case study is an example of a health care associated infection which is an infection acquired in hospital. The type of infection in the case study is a urinary tract infection (UTI) which is the occurrence of pathogens at any point in the urinary tract (Tadesse & Alem, 2006).The defence mechanisms of the urinary tract include surface bladder muscosa, secretary IgA, menstrual flow in females, normal microbial flora and surface bladder mucosa (Tadesse & Alem, 2006).

The causative agents of UTI are gram- negative rods like proteus spp, klesbsiella pneumonia, Escherichia coli, pseudomonas aeruginosa and enterobacter arogens (Tadesse & Alem, 2006).The infection routes of pathogens include the ascending route where bacteria pass from the urethra to the bladder and kidney and the haematogenous route where the infection origin is the blood (Tadesse & Alem, 2006).The clinical features include the lower urinary tract infection which is the infection of the urethra and bladder that is shown by pain during urination, frequent urinating, blood stained urine and ‘NO’ fever is reported.

The upper urinary tract infection that is the infection of the kidney parenchyma and pylus that shows in lower UTI signs and symptoms, fever and chills, vomiting and nausea (Tadesse & Alem, 2006).Laboratory diagnosis involves direct microscopic examinations of white blood cells, erythrocytes and epithelial cells. Existence of more than five white blood cells and many epithelial cells per HPF indicates UTI (Tadesse & Alem, 2006).If the gram stain indicates one bacterium in Uncentrifuged gram stained urine, it indicates UTI (Tadesse & Alem, 2006).

Also culture can be done through blood agar medium and Mac Conkey agar medium. Culture results are interpreted as greater than or equal to 105cfu/ml of urine indicates UTI. Less than 103cfu/ml of urine shows specimen contamination, 103 - 105 cfu/ml of urine is not certain and 103 - 105cfu/ml of urine in catheterized specimen or symptomatic patient shows UTI (Tadesse & Alem, 2006).Genus: PseudonmonasIts characteristics include: Gram negative rods, aerobic and is motile (Tadesse & Alem, 2006).It may be found in water, sewage, soil, human and animal intestine, vegetation (Tadesse & Alem, 2006).

There are two species: Pseudomonas aeruginosa and pseudomallei. Our species of interest is P. Aeruginosa. It is located in animal and human intestines, soil, water and moist areas in hospitals. Primarily, it is a nosocomial bacterium. It invades and triggers infections in hospitalized persons whose host defences are abnormal. It produces toxins. Its antigenic features include exotoxin A which by hindering protein synthesis is cytotoxic, pili to stick to epithelial cells, lipopolysacchride which has an endotoxic effect, exopolysacchride that has anti – phagocytic features and its enzymes include protease, hemolysins, phospholipases C and elastases which digests proteins (Tadesse & Alem, 2006).

Its clinical features are that it’s pathogenic when it is introduced into environments that lack the required defences such as neutropenia of any cause, a broken mucus membrane and the utilization of urine catheter. Urinary tract infection is related with an indwelling catheter (Tadesse & Alem, 2006).Laboratory diagnosis is done by analysis of specimen such as pus, urine, sputum, blood and eye swabs (Tadesse & Alem, 2006).Smears produce gram negative rods while cultures indicate obligate aerobes that grow readily on all routine media on a broad range of temperature that lies between 5 and 42 degrees Celsius (Tadesse & Alem, 2006).

Laboratory results also indicate bluish – green pigmented large colonies that have a characteristic ‘fruity’ odor on the culture media (Tadesse & Alem, 2006).Its biochemical reactions include oxidative positive, catalase positive, citrate positive, indole negative and they secrete acid from carbohydrates by oxidation and not fermentation (Tadesse & Alem, 2006).The bacteria are identified on the basis of oxidase – positivity, colony morphology, groth at 42 degrees Celsius and a characteristic pigment secretiom (Tadesse & Alem, 2006).

Treatment can be done through administration of the following medications, Aztreonam, Imipenem, Ticarcillin, Fluoroquinolones and Cefoperazone (Tadesse & Alem, 2006).The pathogen can be prevented and controlled by ensuring that water baths, showers, sinks and hot baths are clean. These are the reservoirs (Tadesse & Alem, 2006).Polyvalent vaccine should be given to vulnerable groups (Tadesse & Alem, 2006).BibliographyTadesse, A. & Alem, M., 2006. Medical Bacteriology [pdf] Available at: http://www.

cartercenter.org/resources/pdfs/health/ephti/library/lecture_notes/env_occupational_health_students/medicalbacteriology.pdf [Accessed 8 April 2014].