Evaluation of Some Clinical Chemistry Parameters of Wistar Rats Induced with Staphylococcus aureus from Clinically Diagnosed Pneumonia Patients

Introduction

Staphylococcus aureus is the most pathogenic specie of the genus Staphylococcus with a diameter of 0.5-1.5µm [1]. This gram positive coccal bacterium belongs to the family staphylococaceae which is a member of the fermicutes. They are frequently found as a commensal residing on the skin, skin glands, respiratory tract and on the nose of healthy individuals [2]. It is a non-moving small round shaped coccus found in grape like (staphylo-) clusters, hence it is called Staphylococcus. Staphylococcus aureus owes its ability to cause disease, in part, to the production of a repertoire of virulence factors that modulate its ability to colonize host/ inert surfaces, thwart host defenses, and disseminate to satellite sites [3].

S. aureus is a versatile human pathogen causing infections ranging from relatively mild skin and soft tissue infections to life threatening sepsis, pneumonia, osteomyelitis, endocarditis as well as toxin mediated syndromes such as toxic shock syndrome and food poisoning [4]. Staphylococcus aureus is able to cause a large diversity of both benign and lethal infections in humans and animals because of a wide range of virulence factors that include various toxins and enzymes [5]. It has emerged as one of the most popular human pathogens and has become a leading cause of hospital (nosocomial) and community acquired infections [6].

Staphylococcus aureus is usually a harmless colonizer most likely to be found in the nares of about one third of healthy persons. Colonization increases the risk of subsequent infection since those S. aureus infections are usually infected with their colonizing strain [7]. A breach of the skin or mucosal barrier allows the organism to gain access into adjoining tissues or the blood stream causing infection [8].

Antibiotics could be used for the treatment of most Staphylococcal infections; but in recent years Staphylococcus aureus have been found to develop resistance against some of these used effective antibiotics found. Lincosamides, macrolides, streptogramin, tetracycline, gentamycin and beta-lactams, particularly methicillin are some examples of the antibiotics used [9].

Pneumonia infection is usually caused by Streptococcus pneumonia. But Staphylococcus aureus is now a common cause of pneumonia, the most frequent pathogen identified with health care-associated pneumonia as well as a major cause of superinfection and mortality after influenza [10]. Staphylococcus aureus pneumonia is a potentially life- threatening infection caused by this human pathogen. The only therapies available to treat S. aureus pneumonia are antibiotics, a modality that is jeopardized by the organism’s remarkable ability to acquire antimicrobial resistance. The cytotoxin, alpha- hemolysin produced by S. aureus is essential for the pathogenesis of pneumonia.

The primary form occurs without an extrapulmonary focus, presumably through direct inoculation to the lungs, and the secondary form results from hematogenous seeding of the lungs during endocarditis or bacteremia.

Pneumonia is a serious and rapidly progressive infection which is associated with high incidence of complications and mortality unless recognized early and treated appropriately [11]. Pneumonia is an inflammatory condition of the lung affecting primarily the microscopic air sacs known as the alveoli. Viruses or bacteria and less commonly other microorganisms, certain drugs and other conditions such as autoimmune diseases are common causes of pneumonia.

Pneumonia is sometimes referred to as the forgotten killer. The World Health Organization estimates that lower respiratory tract infection is the most common infectious cause of death in the World with almost 3.5 million deaths yearly (Geneva: World Health Organization, 2013).Together, pneumonia and influenza constitute the ninth leading cause of death in the United States, resulting in 50,000 estimated deaths in 2010 [12].

Pneumonia is a common illness affecting approximately 450million people a year and occurring in all parts of the world [13]. It is a major cause of death among all age groups resulting in 4million deaths (7% of the world’s total deaths) yearly [13, 14]. Rates are greatest in children less than five, and adults older than 75years. There is high risk of pneumonia in the developing world compared to developed world. Viral pneumonia accounts for about 200million cases. In the United States, as of 2009, pneumonia is the 8th leading cause of death [15]. In the terminally ill and elderly especially those with other conditions, pneumonia is often the immediate cause of death. In such cases, particularly when it cuts short the suffering associated with lingering illness, pneumonia.

S. aureus may occur commonly in the environment and is transmitted through air droplets or aerosol. When an infected person sneezes or coughs, he or she releases numerous small droplets of saliva that remain suspended in air. These contain the bacteria and can infect others. Following exposure, the organism may establish itself in the nasopharynx of its host usually resulting in asymptomatic colonization. The organism can be carried for a period of weeks to months. However sometimes, the newly acquired pneumococcus invades host defensive mechanisms and causes illness [16].

Clinical chemistry, a branch of Clinical medicine that deals with body fluids, is based on the basic principle that a disease causes changes in the biochemistry of the body. It may cause either increase in concentration, or decrease in concentration of certain biochemical parameters or even may cause a different substance to appear. Hence, clinical biochemistry deals with changes in the composition of blood and other body fluids which are associated with the diagnosis of disease or monitoring the therapy [17]. The Hematological and blood clinical chemistry could aid in the determination of the health status, diagnosis and prognosis of disease [18].

The objective of the present study was to determine the ability and prevalence of staphylococcus aureus to induce pneumonia with a view to providing information on the chemistry parameters of clinically diagnosed pneumonia patients.

Materials and Methods

The materials used for this experiment include autoclave, universal bottles, incubator (model:GP/50/CLAD/250/HYD), spirit lamp, measuring cylinder, Beam balance (Harvard trip 1400/1500 series) , wire loop, hot air oven(model; Gp/50/ CLAD/250/HYD),forceps, Pasteur pipettes, bijou bottles, latex gloves, Petri dishes, weighing balance, Wistar rats, test tubes, beakers, McCartney bottles, spatula, 2ml syringes and needles, dissecting kits, coloured markers, mannitol salt agar, non-heparinized micro- hematocrit capillary tubes, Spectrophotometer, chloride calibrator, Timer, Centrifuge, cotton wool. The reagents used includes; nutrient broth, sterile distilled water, disinfectant, chloride reagent.

Results and Discussion

Staphylococcal pneumonia is a generally progressive process in all age groups. Two main forms are recognized:

primary pneumonia due to direct inoculation through the respiratory tract and secondary or metastatic haematogenesis lung infection due to bacteremic seeding to the lung during the course of septicemia associated with the other sites of infection.

In this study, 79 patients were diagnosed to have pneumonia caused by Staphylococcus aureus. The various serum chemistry concentrations for sodium, potassium, chloride, creatinine and urea where determined.

For the control, the values obtained for Urea, Creatinine, Sodium, Potassium and Chloride were 14mg/dl, 0.47mg/dl, 136mmol/l, 4.8mmol/l and 98mmol/l respectively.

In respect to changes that occur in serum electrolytes, the results of this study show that there was a significant reduction in serum concentration of sodium and chloride while serum values of potassium were significantly increased [19].

Some studies conducted attributed the changes occurring in serum electrolytes during the course of respiratory disease to the hyperpyrexia in the acute course of the disease and metastatic infection of liver and kidneys resulting in hepatic and renal dysfunction [20].

High serum potassium levels usually occur in respiratory diseases especially if acidosis is present because H+ ions accumulated in the extracellular fluids (ECF) is exchanging with potassium in the intracellular (ICF) leading to hyperkalemia [21].

From the result above, it can be inferred that the level of potassium was relatively high (Hyperkalemia) compared to the normal range of 3.5 to 5.0. Hyperkalemia is serum potassium >5.5 milliequivalents per liter, hence any level greater than 6mEq can be life-threatening, depending on the clinical setting [22, 23]. Normal blood levels of potassium are critical for maintaining normal heart electrical rhythm. High blood potassium levels can lead to abnormal heart rhythm. Another important effect of hyperkalemia is interference with functioning of the skeletal muscle [24]. Central Hospital Ughelli had the highest mean value for potassium (8.02+0.779), CO for Urea, Yen for creatinine, Central Hospital Benin for sodium and Central Hospital Sapele for Chloride. For urea, pneumonia induced by staphylococcus aureus had no significant effect. This may be due to the level of infection or virulence of the organism on the pneumonia patient. Sodium levels drastically reduced (Hyponatremia) with the exception of SAP41, SAP83 and CB4. Increased sodium in the blood occurs whenever there is excess sodium in relation to water. Hypernatremia could be caused by kidney disease, too little water intake and loss of water due to diarrhea and vomiting. Usually patients with pneumonia are at high risk of experiencing low sodium levels since the principal organ of effect is the lung with continuous production of cough with sputum. Pneumonia also affects the gastrointestinal tract (GIT) causing nausea, vomiting and diarrhea. Due to loss of fluids, it is worthy to note here that the removal of sodium is faster than that of water from the body.

Conclusion

This study is based on the ability of Staphylococcus aureus isolated from pneumonia patients to cause changes in the clinical chemistry parameters of the body. These physiological changes in potassium, urea, sodium, creatinine, and chloride where determined using spectrophotometric methods. It can be concluded that the staphylococcus aureus isolated from clinically diagnosed pneumonia patients was capable of altering the body’s electrolyte level causing increase in potassium and decreased sodium and chloride levels. There were slight changes in the urea level with a remarkable effect on the creatinine level.

Conflict of Interest

No conflict of interest.

Acknowledgment

All staff of the department of Pharmaceutical Microbiology and Biotechnology are immensely appreciated for their support.