RELEVANCE OF BLOOD CULTURE TO THE DIAGNOSIS AND TREATMENT OF SEPTICEMIA

Code No: 645387

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ABSTRACT

A study of septicaemia was conducted in Enugu metropolis with a view to determine the relevance of blood culture to the diagnosis and treatment of this disease. The subjects comprised of three hundred and fifty (350) children and adults of both sexes aged between one day to 70 years having clinical features suggestive of septicaemia, who were on admission at University Of Nigeria Teaching Hospitals (UNTH), Enugu. Their blood specimens were seeded into thioglycolateand glucose broths and incubated at 37 Â°C for 7 days. Subcultures were performed after 1, 2, 3, 4 and 7 days respectively. Growth (positivity) in the broths was assessed using conventional diagnostic methods namely macroscopy(visualization), Gram filming (microscopy) and culture. The bacterial isolates harvested were subjected to in-vitroantibiotic susceptibility tests using the disc diffusion method. Etiology was established in 104 out of 350 subjects indicating an incidence of 29.7%.
This difference in prevalence among different age groups was statistically significant(P < 0.01). The males (59/350, 16.86%) appeared to be more susceptible to septicaemia than the females (45/350, 12.9%) in all the age groups.
This variation had no statistical significance (P > 0.01). Monomicrobialsepticaemia had ahigher prevalence (91.3%) than polymicrobialsepticaemia (8.65%). Staphylococcus aureusand Escherichia coliconstituted 33.3%. Most of the offensive microbes were facultative anaerobes (93.3%) while very few were strict aerobes (7.69%) and strict anaerobes (1.92%). The isolated anaerobes were Peptostreptococcussp. (1%) and Bacteroidesfragilis(1%). The in vitro susceptibility of the bacterial isolates to antibiotics indicated 78.9-92.9% sensitivity to vancomycin, zinnat, peflacin and fortum. However, they were 60 â€“ 90% resistant to penicillin, ampicillin, tetracycline and septrin. This study confirmed the diverse nature of bacterial etiologies of septicaemia in Enugu metropolis; the need for the use ofthioglycolate broths, first subcultures on or before 24 h instead of starting off for after 48 h of incubation, complementary application of macroscopy, Gram filming and culture including antibiotic susceptibility test as an integral part of diagnosis and treatment of septicaemia is hereby advocated, most especially in the developing countries of the world.

CHAPTER 1

CHAPTER ONE
1.0 INTRODUCTION
Blood is normally sterile in healthy individuals. It is the main transport mechanism connecting all different parts of the body. As it serves as a transport system for oxygen, food materials, waste products and others round the body, it can also carry microbes (Eugene et al., 1998). However, it has no normal flora and the presence of microorganism in it indicates failure of the defence mechanisms to maintain its sterility. In many cases such a failure is transitory and of no clinical importance but in others, it is serious and life threatening. Lymphoid tissue is an important part of the defence system acting as a filter to intercept potentially invasive pathogens as well as being the headquarter of the lymphocytes on which immunity is heavily dependent. This filter system is however liable to clinically significant infections by intercepted pathogen and it is also the primary target for some factors of infection (Douglas et al., 1981). The involvement of blood, lymphatic system and heart in many infections give us the knowledge of the presence of bacteria in the blood.
Various authors have reported bacteraemia immediately after incision of an abscess, tonsillectomy and tooth extraction (Fischer et al., 1941; Murry et al., 1941). Robert et al. (1997) described bacteraemia as a transitory disease in which bacteria present in the blood are usually eliminated from the vascular system by the reticulo endothelial system with no harmful effect, but in host with reduced immunity, septicaemia results.
The term septicaemia is often used in describing severebacteraemic infections or a condition in which the blood serves as a site of bacteria multiplication as well as a means of transfer of the infectious agent from one site to the other. The clinical picture frequently present in septicaemia is that of septic shock which is recognized by a severe febrile episode with chills, fever, malaise, tachycardia mental confusion, hyperventilation and toxicity, a hypotension (drop in blood pressure) and prostration which results when circulating bacteria multiply at a rate that exceeds their removal by phagocytes. Complications include disseminated intravascular coagulation (DIC) and acute renal failure (Shanson, 1999).
The mortality rate varies between 15 and 35%, depending on the age, the underlying condition and the treatment given (Shamson, 1998). Prompt recognition of septicaemia and immediate treatment based on the knowledge of the likely causative organism is essential. Septicemias which are of bacterial origin are caused by myriads of bacteria varying from one locality to another. Many studies on septicaemia in Nigeria have been on neonates and childhood and also retrospective (Dawodu et al., 1980) and there is therefore paucity of information on prospective study on septiceamia in different strata of society in Nigeria.