THE IMPORTANCE OF BLOOD CULTURES IN THE DIAGNOSTIC AND THERAPEUTIC PROCESS OF SEPTICEMIA

CHAPTER ONE

INTRODUCTION: In healthy people, the blood is completely devoid of bacteria. It is the primary transport mechanism that links all of the various components of the body together. Because it functions as a transport system throughout the body, carrying oxygen, food items, waste products, and other substances, it is also capable of carrying microorganisms (Owa, & Olusanya, 2022). However, it does not have any regular flora, and the fact that it contains microorganisms demonstrates that the defence mechanisms that were supposed to keep it sterile have failed. In many situations, a failure of this kind is very temporary and has little bearing on patient care, but in others, it can be extremely dangerous and even fatal. Lymphoid tissue is an important component of the immune system because it serves as a filter to prevent potentially invasive infections from entering the body. Additionally, lymphoid tissue is the headquarters of lymphocytes, which are an essential component of immunity. However, there is a risk of clinically severe infections caused by pathogens that are captured by this filter system, and it is also the prime target for some factors that contribute to infection (Reller, Murray, & MacLowry, 2022). The fact that germs are found in the blood is established by the fact that the blood, the lymphatic system, and the heart are all involved in the transmission of many infections.

Immediately following the removal of an abscess, tonsillectomy, or tooth extraction, bacteraemia has been documented by a number of different writers (Roberton, 2022). According to Robert et al. (2022), bacteraemia is a transient disease in which bacteria that are present in the blood are typically removed from the vascular system by the reticulo endothelial system without causing any harmful effects. However, septicaemia can develop in hosts that have a compromised immune system (Owa, & Olusanya, 2022).

The condition in which the blood serves as a site for bacteria multiplication as well as a means of transfer of the infectious agent from one site to the other is referred to as septicaemia. The term "septicaemia" is frequently used when describing severe bacteraemic infections or a condition in which this occurs. The clinical picture that is frequently seen in septicaemia is that of septic shock, which can be identified by a severe febrile episode with chills, fever, malaise, tachycardia mental confusion, hyperventilation and toxicity, a hypotension (drop in blood pressure) and prostration. Septic shock happens when circulating bacteria multiply at a rate that is faster than their removal by phagocytes. Acute renal failure and disseminated intravascular coagulation (DIC) are two of the complications that can arise (Owa, & Olusanya, 2022).

The mortality rate ranges anywhere from 15% to 35%, contingent upon the patient's age, the nature of the underlying disease, and the treatment that they receive (Reller, Murray, & MacLowry, 2022). Important first steps in treating septicemia include prompt diagnosis of the condition and an understanding of the organism that is most likely to be the cause. Septicemias that are caused by bacteria are caused by a vast number of bacteria that might vary greatly from one geographic location to another. Numerous studies on septicaemia in Nigeria have been conducted on newborns and children, in addition to being retrospective (Roberton, 2022), and as a result, there is a scarcity of information on prospective studies on septiceamia in various strata of society in Nigeria.

1.1 BLOOD CULTURE

This is a culture of blood microbiologically that is employed for the detection of diseases which are spreading through the bloodstream. One of such disease is septicemia. This culture of blood is possible because the bloodstream is usually a sterile environment and it is carried out through a laboratory test which will check for bacteria or other microorganisms in a blood sample. Most cultures check for bacteria. A culture may be done using a sample of blood, tissue, stool, urine, or other fluid from the body.

When signs or symptoms of a systemic infection is noticed in a patient, results from a blood culture can verify that an infection is present, and they can identify the type (or types) of microorganism that is responsible for the infection. A good example is when blood tests identifies the causative organisms in neonatal epiglottitis, sepsis, severe pneumonia, puerperal fever and fever of unknown origin (FUO). However, negative growths do not exclude infection. The usual risks of venipuncture and the occurrence of false positive results approximately 3%+ of the time, can lead to inappropriate treatment (Madeo et al., 2003).

1.2 SEPTICAEMIA

Septicaemia is often referred to as either blood poisoning, bacteremia or sepsis, although it could be argued that each of the terms are not entirely accurate, but are often used interchangeably by scientists (Al-Khafaji et al., 2010). Sepsis is not just limited to the blood and can affect the whole body, including the organs.

Septicaemia (another name for blood poisoning) refers to a bacterial infection of the blood, whereas sepsis can also be caused by viral or fungal infections.

Septicaemia also known as Sepsis is a condition that arises when the body’s response to infection injures its own tissues and organs (Deutschman and Tracey, 2014).Common signs and symptoms include fever, increased heart rate, increased breathing rate, and confusion. (CDC, 2014). There may also be symptoms related to a specific infection, such as a cough with pneumonia, or painful urination with a kidney infection. In the very young, old, and people with a weakened immune system, there may be no symptoms of a specific infection and the body temperature may be low or normal rather than high(Martí-Carvajal et al., 2012). Severe sepsis is sepsis causing poor organ function or insufficient blood flow. Insufficient blood flow may be evident by low blood pressure, high blood lactate, or low urine output. Septic shock is low blood pressure due to sepsis that does not improve after reasonable amounts of intravenous fluids are given (Dellinger et al., 2013).

Sepsis is caused by an immune response triggered by an infection (Jui, 2011; Deutschman and Tracey, 2014).  The infection is most commonly bacterial, but it can also be from fungi, viruses, or parasites (Jui, 2011) Common locations for the primary infection include: lungs, brain, urinary tract, skin, andabdominal organs. Risk factors include young or old age, a weakened immune system from conditions such as cancer or diabetes, and major trauma or burns (CDC, 2014). Diagnosis is based on meeting at least two systemic inflammatory response syndrome (SIRS) criteria due to a presumed infection. Blood cultures are recommended preferably before antibiotics are started; however, infection of the blood is not required for the diagnosis (Jui, 2011). Medical imaging should be done to look for the possible location of infection (Patel and Balk, 2012).  Other potential causes of similar signs and symptoms include: anaphylaxis, adrenal insufficiency, low blood volume, heart failure, andpulmonary embolism among others (Jui, 2011).

1.3 OBJECTIVES OF THE RESEARCH

This objectives of this research are to;

Determine the relevance of blood culture to the diagnosis and treatment of septicaemia.

Compare the occurrence of Gram positive and Gram negative bacteria in the subjects with culture – proven septicaemia.

Determine which gender(male or female) is more prone to septicaemia.

1.4  JUSTIFICATION

It is important to ensure that bloodstream infections are diagnosed accurately and that infecting pathogens, their antimicrobial susceptibilities, and the possible primary sources of infection are evaluated thoroughly, to enable optimal targeted antimicrobial therapy.Blood cultures and their microbiological analysis are highly essential and important for the diagnosis and treatment of septicaemia (sepsis).Blood culture is important for early diagnosis and treatment of patients with septicaemia as survival depends on early detection and administration of adequate empirical antimicrobial therapy.