Bacteremia

What is Bacteremia?

Bacteremia is the medical condition involving the presence of foreign micro-organisms called bacteria in the usually sterile environment of the blood. Bacteremia is otherwise known as “blood poisoning” in layman’s terms, although the expression can be misleading as the condition does not at all involve the contamination of the blood with toxic substances, but with bacterial infestation.

Bacteremia can occur through a number of ways. The entry of bacteria into the bloodstream can be facilitated through a preceding bacterial infection that may complicate progressively, allowing the micro-organisms to reach the blood vessels and proliferate while remaining in the patient’s blood. Bacteremia may also occur as an unintentional complication of surgery, a consequence which is highly possible if the surgical procedure is not performed with sterile instruments or within a sterile environment. Bacteria can also opportunistically take advantage of other means to enter into a person’s system, such as through catheters used for medical purposes as well as through intravenous insertions like parenteral drug administration.

The condition is one that should not be taken lightly as it can quickly become a seriously life-threatening situation, especially if the bacteria are able to move and reproduce quickly enough to migrate to other parts of the body and overwhelm the system with its numbers, causing systemic affectation and leading to debilitating consequences. If left uncontrolled and untreated, the bacterial infection within the blood can bring about a wide-spread inflammatory response in the vast majority of the body, setting the stage for potential septic shock and highly increased mortality.

The first observable signs and symptoms of bacterial infection should be addressed in a timely manner, to provide prompt treatment and prevent worsening of the condition.

Bacteremia Symptoms

The following are the most commonly observed and reported symptoms of a bacterial infection in the blood. These include the classic signs of infection that come up as a result of the body’s immune response reacting to the presence of the foreign micro-organisms in the bloodstream.

• High fever
• Chills
• Increased heart rate (tachycardia)
• Pain felt in the abdominal region
• Nausea and vomiting
• Severe body malaise
• Weakness and fatigue
• Rapid breathing, usually more than 20 breaths per minute
• Productive cough

A diagnosis of bacteremia is not arrived at through mere reported symptoms. To further ascertain the diagnosis, the doctor will usually order a set of laboratory examinations to test the patient’s blood and confirm the bacterial infection. Certain laboratory findings will determine the diagnosis. This includes the white blood cell count which, if found to be abnormally high, will indicate that an immune response has been initiated in the body, signalling the presence of a bacterial infection.

Bacteremia Treatment

Once bacteremia is positively diagnosed, the patient must be treated through hospitalization, intravenous antibiotic administration, and a full therapeutic care regimen that manages any organ affectation that may have already occurred.

Antibiotic medications most commonly given to bacteremia patients are composed of a combination of antibiotics, instead of utilizing a single type of drug alone. The most frequently prescribed antibiotic for many bacteremia cases includes vancomycin as part of the drug regimen. Over time, close observation of the patient will eventually yield findings that can single out the most effective antibiotics for the particular type of infection a patient may be suffering from, reducing the requirement for the simultaneous use of multiple drugs.

In the event that the infection has progressed and come to affect vital organ function, medical equipment may be used to support the damaged organ. For instance, infection of the lungs and subsequent impairment of the respiratory system is helped through intubation. If organ infection is severe, the medical team may also have to resort to surgery in order to manually remove or drain the products of infection from the body. In severe cases, amputation may even sometimes be a last resort, in order to prevent the spread of a dangerous infection that can possibly cause death.

MSSA Bacteremia

MSSA Bacteremia is a form of blood poisoning caused by the bacteria known as staphylococcus aureus. This type of bacteremia is the most common kind of bacteremia that is identified and is the easiest to treat as the strains of bacteria are easily vulnerable to penicillin antibiotics, earning this form of the condition its label as MSSA Bacteremia or Methicillin-sensitive Staphylococcus Aureus.

MRSA Bacteremia

MRSA Bacteremia, or Methicillin-resistant Staphyloccus aureus bacteremia is much more difficult to treat in comparison to its contrasting form of MSSA Bacteremia which is easily sensitive to penicillins. MRSA bacteremia is otherwise known as multidrug-resistant staphylococcus aureus due to its ability to withstand treatment in the form of beta-lactam antibiotics such as penicillins, as well cephalosporins. The defiance to most forms of antibiotic treatment makes this type of bacteremia more life-threatening especially if individualized treatment for the type of bacterial infection found is not initiated in time.

E Coli Bacteremia

E. Coli Bacteremia is another common form of bacterial infection. Escherichia coli, the causative agent of the sickness, is one of the most commonly found culprits in cases of bacteremia that may have progressed from a preceding case of urinary tract infection, cholecystitis, cholangitis, or pneumonia.

Bacteremia that takes this form is treated through antibiotic medications, specifically through third-generation cephalosporins or fluoroquinolones. A host of other antibiotic medications are also used, these include doxycycline, amoxicillin, ampicillin, ceftriaxone, and aztreonam – among others.

Antibacterial therapy will most typically be required to be maintained for a period of at least 2 weeks. The drug regimen will be sustained in conjunction with usual supportive care in the form of preserving adequate hydration and oxygenation of the patient.

Occult Bacteremia

Occult Bacteremia is one that is difficult to detect and may even simply be coincidentally stumbled upon during a patient’s routine physical work-up. The condition does not manifest itself through many symptoms other than through fever and body malaise, in most cases. The patient will not complain of any other types of discomfort but diagnosis of the condition can be made through blood examination. Occult bacteremia is most commonly caused by Streptococcus penumoniae, which may potentially travel through the bloodstream and cause serious organ infection such as pneumonia or meningitis. In order to eliminate the problem, this type of bacteremia is treated through prescription antibiotics.

Enterococcal Bacteremia

Enterococcal Bacteremia is brought about by any of the members of the group of bacteria known as Enterococci. These micro-organisms are actually found naturally in the intestinal environment, specifically those of the species E. faecalis and E. Faecium, but are still however, capable of triggering serious infections if allowed to access other regions of the body. This can usually become possible through hospital acquired infections – otherwise known as nosocomial infections.

Bacteremia taking this form usually arise from initial bacterial infection in the urinary tract, or through meningitis or diverticulitis. Although increasingly resistant to antibiotic therapy, enterococcal bacteremia are still suscepbtible to treatment through ampicillin and vancomycin.

Staph aureus Bacteremia

Staphylococcus aureus is one of the leading causes of recorded cases of bacteremia. Bacteremia stemming from a preceding staph aureus infection may originally result from a great variety of initial infections, since S. aureus is an extremely versatile infectious agent and can cause disease including but not limited to minor skin infections, pneumonia, meningitis and even endocarditis. The infection is most commonly acquired as a nosocomial illness that progresses through lack of detection and treatment.

Treatment for usual forms of this type of bacteremia was most effective through penicillin, however, penicillin-resistant forms of staph infections has emerged and have thus warranted different treatment. Such cases are treated through oxacillin or flucloxacillin, a pair of antibiotics which are capable of resisting the penicillinase release by penicillin-resistant species of S. aureus. The penicillin antibiotic may be used in conjunction with gentamicin especially for cases which are manifesting heart affectation in the form of endocarditis.

Gram negative Bacteremia

Gram negative Bacteremia is a broad term used to indicate any type of blood poisoning brought about by any of the bacteria classified as gram-negative bacteria. These include proteobacteria such as E. coli, salmonella, and Shigella as well as other types of bacteria including Neisseria gonorrheae and Haemophilus influenzae. Each of these agents are responsible for causing their own respective illnesses, such as sexually transmitted diseases, meningitis, and respiratory and gastrointestinal problems.

Gram-negative bacteria are unique due to the distinct protective structure of their cell walls, granting them protection from certain antibiotics. However, drugs have been developed to combat these particular infections, such as ampicillin, chloramphenicol, streptomycin, and nalidixic acid.

Strep viridans Bacteremia

Caused by a form of strep infection known as Streptococcus Viridans, bacteremia brought about S. Viridans will initially emerge from an initial infection in the mouth as these are most commonly found in the environment of the oral region. They are able to proliferate through mouth or gingival infections and can then pass through the bloodstream, potentially causing endocarditis if able to reach the heart. Thankfully, strep viridans infections can be treated with the use of most types of antibiotics, such as penicillin and vancomycin.

Klebsiella Bacteremia

Klebsiella is one type of bacteria able to cause a variety of possible conditions, including pneumonia and urinary tract infections. As a type of gram-negative bacteria, bacteremia caused by klebsiella can be treated through antibiotics like ampicillin, chloramphenicol, streptomycin, and nalidixic acid.

VRE Bacteremia

VRE Bacteremia or Vancomycin-resistant Enterococcus Bacteremia is a unique and dangerous form of infection. The enterococcus are part of the normal flora within the gastrointestinal tract, but if allowed to migrate to other regions of the body, can set off an illness in the form of infection. Although Vancomycin is generally capable of treating many types of bacterial infection, VRE is one that has grown resistant to the antibiotic – a mutation said to arise due to previous use of vancomycin.

It is not typically a dangerous infection, if the patient is of good health and with a healthy immune system, but it is however a serious case for immunocompromised individuals as treatment is extremely difficult due to the infection’s resistance to antibiotic treatment.

In order to overcome the resistance, newer antibiotics have been developed to combat this particular infection. These are used in combination with other antibiotic drugs to increase efficacy. Some drug combinations currently in use include teicoplanin and amoxicillin, or ampicillin, vancomycin, and imipenem.

Staphylococcal Bacteremia

Staphylococcal bacteremia is a general term for any blood infection caused by any type of staphylococcus bacteria, the most common agent being S. aureus. The condition is often a cause for worry due to high mortality rates associated with this type of bacteremia, since it is capable of systemic infection that may affect critical organs – most notably the heart, bringing about serious endocarditis. An assortment of antibiotics are used for staphylococcal bacteremia, including nafcillin, vancomycin, telavancin, cefazolin, clindamycin, dicloxacillin, and daptomycin.