Septicemia, bacteremia, “bacteria in the blood”

500M cases in United States/annum

25% mortality rate

10% of patients with sepsis die of underlying disease or comorbidity

13th leading cause of death in the United

States

Cost 5-10 billion in annual healthcare expenditures

50% of all cases of sepsis are caused by gram negative rods

other etiologies include:CNSStaphylococcus aureusEnterococcus spFungi (yeast)

The numbers of sepsis are predicted to increase:

larger numbers of immunocompromised patientsmore frequent use of invasive procedures or devicesgreater availability of life-sustaining technologyhigher infection rates of antibiotic resistant bacteriaincrease proportion of patients at the extremes of age

Among hospitalized in non-coronary intensive

care units, sepsis has been reported to be the

most common cause of death.

The term systemic inflammatory response syndrome (SIRS)was developed to imply a clinical response from a non-specific etiology.

SIRS is defined as two or more of the following:temperature above 38 C or below 36 Cheart rate above 90 beats/minuterespiratory rate above 20/minute P CO2 less than 32 mm Hgwhite blood count above 12M or below 4M cells/mm3

presence of more than 10% immature neutrophils

A severe form of gangrene (tissue death) usually caused by Clostridium perfringens (see also necrotizing subcutaneous infection). It can also be from Group A Streptococcus. Staphlyococcus aureus and Vibrio vulnificus can also cause similar infections.

Gas gangrene occurs as a result of infection by Clostridium bacteria. Under anaerobic (low oxygen) conditions, produce toxins that cause the tissue death and associated symptoms.

Gas gangrene generally occurs at the site of trauma or a recent surgical wound.

Symptoms   ◦ moderate to severe pain around a skin

injury ◦ progressive swelling around a skin

injury ◦ moderate to high fever ◦ skin color initially pale, later dusky

progressing to dark red or purple ◦ Vesicle (blister) formation, coalescent

(combine into large blisters) ◦ blisters filled with brown-red fluid ◦ drainage from the tissues, foul-

smelling brown-red or bloody fluid (serosanguineous discharge)

◦ increased heart rate (tachycardia) ◦ sweating ◦ subcutaneous emphysema (air under

the skin)

Treatment   ◦ Prompt surgical removal of dead,

damaged, and infected tissue (debridement) is necessary. Amputation of an arm or leg may be indicated to control the spread of infection.

◦ Antibiotics, preferably penicillin-type, should be given. Initially, this is given intravenously (through a vein). Analgesics may be required to control pain. Hyperbaric oxygen has been tried with varying degrees of success.

◦ Hyperbaric treatment Prognosis   

◦ Gas gangrene is progressive and often lethal. Immediate medical attention is required.

Yersina pestis is the causative agent.

Three clinical manifestations:Pneumonic SepticemicBubonic

In early stages of bubonic there is fever, delirium, and swelling of lymph nodes. Septicemia

develops and cause hemorragic blackened lesion therefore black death

Plague is transmitted among

rodents and to humans by flea bite

or ingestion of the feces of fleas.

It can also be transmitted human

to human when a plague victim

develops pneumonia and spreads

infected droplets by coughing.

An epidemic may be started this

way.

Symptoms    Sudden onset of high fever Chills General discomfort, uneasiness, or

ill feeling (malaise) Muscular pains Severe headache Smooth, oval, reddened, painful

swellings of swollen lymph glands called buboes in the groin, armpits, neck, or elsewhere in the body. Pain may occur in the area before the swelling; the most common area is in the groin

Seizures

Treatment   ◦ Immediate treatment with

antibiotics such as streptomycin, chloramphenicol, or tetracycline is indicated. Oxygen, intravenous fluids, and respiratory support are additional treatments.

◦ Patients with pneumonic plague are strictly isolated from other patients.

◦ People who have had contact with anyone infected by pneumonic plague are observed closely and are given antibiotics as a preventive measure.

Prognosis   ◦ Half of bubonic plague

victims die if not treated, and almost all victims of pneumonic plague die if not treated. Treatment reduces the death rate to 5%

Borrelia burgdorferi is a species of Gram negative

bacteria of the spirochete class of the genus

Borrelia. B. burgdorferi is predominant in North

America, but also exists in Europe, and

is the agent of Lyme disease.

It is a zoonotic, vector-borne disease transmitted

by ticks and is named after the researcher Willy

Burgdorfer who first isolated the bacterium in

1982.

B. burgdorferi is one of the few pathogenic

bacteria that can survive without iron, having

replaced all of its iron-sulfur cluster enzymes with

enzymes that use manganese, thus avoiding the

problem many pathogenic bacteria face in

acquiring iron.

Borrelia burgdorferi infections have been

linked to non-Hodgkin lymphomas.

Lyme disease is diagnosed based on

symptoms, objective physical findings

(such as erythema migrans, facial palsy,

or arthritis), and a history of possible

exposure to ticks. Validated laboratory

tests can be very helpful but are not

generally recommended when a patient

has erythema migrans.

The Lyme disease bacterium, Borrelia

burgdorferi, normally lives in mice,

squirrels and other small animals.

It is transmitted among these animals

and to humans through the bites of

certain species of ticks. In the

northeastern and north-central

United States, the black-legged tick

(or deer tick, Ixodes scapularis)

transmits Lyme disease.

Antibiotics commonly used for oral treatment

include doxycycline, amoxicillin, or cefuroxime

axetil. Patients with certain neurological or

cardiac forms of illness may require intravenous

treatment with drugs such as ceftriaxone or

penicillin.

Patients treated with antibiotics in the early stages

of the infection usually recover rapidly and

completely.

A few patients, particularly those diagnosed with

later stages of disease, may have persistent or

recurrent symptoms.

Scientists have concluded that longer courses of

antibiotic treatment are not beneficial.

Longer courses of antibiotics have been linked to

serious complications, including death.

Brucellosis is an infectious disease caused

by the bacteria of the genus Brucella.

These bacteria are primarily passed among

animals, and they cause disease in many

different vertebrates.

Various Brucella species affect sheep, goats,

cattle, deer, elk, pigs, dogs, and several other

animals.

Humans become infected by coming in contact

with animals or animal products that are

contaminated with these bacteria.

In humans brucellosis can cause a range of

symptoms that are similar to the flu and may

include fever, sweats, headaches, back pains, and

physical weakness.

Also known as undulating fever (higher at night),

muscle aches, enlarged spleen and lymph nodes

Severe infections of the central nervous systems

or lining of the heart may occur. Brucellosis can

also cause long-lasting or chronic symptoms that

include recurrent fevers, joint pain, and fatigue.

Mainly an infection of livestock.

Human cases are reported as:

60% butchers, meat packers

30% ranchers and hunters

10% people who consume unpasteurized dairy products

Brucellosis is diagnosed in a

laboratory by finding Brucella

organisms in samples of

blood or bone marrow.

Also, blood tests can be done to

detect antibodies against the

bacteria.

If this method is used, two blood

samples should be collected 2 weeks

apart.

Treatment can be difficult. Doctors can

prescribe effective antibiotics.

Usually, doxycycline and rifampin are used

in combination for 6 weeks to prevent

reoccuring infection.

Depending on the timing of treatment and

severity of illness, recovery may take a few

weeks to several months.

Mortality is low (<2%), and is usually associated

with endocarditis.

Francisella tularensis, the organism that causes tularemia, is one of the most infectious pathogenic bacteria known, requiring inoculation or inhalation of as few as 10 organisms to cause disease.

It is considered to be a dangerous potential biological weapon because of its extreme infectivity, ease of dissemination, and substantial

capacity to cause illness and death.

Francisella tularensis is a hardy non-spore forming organism that is capable of surviving for weeks at lowtemperatures in water, moist soil, hay, straw or decaying animal carcasses.

Tularemia is a zoonosis. Natural reservoirs

include small mammals such as voles, mice, water rats, squirrels, rabbits and hares.

Naturally acquired human infection occurs

through a variety of mechanisms such as:

bites of infected arthropods; handling infectious animal tissues or fluids; direct contact or ingestion of contaminated water, food, or soil; and inhalation of infective aerosols.

F. tularensis is so infective that examining an open culture plate can cause infection.

Humans can contract tularemia in the following ways:

direct contact with an infected animal or carcass via broken skin

the bite of an infected flea, deer fly, or tick

ingesting infected meat (rare)

  red spot on the skin,

enlarging to an ulcer enlarged lymph nodes of

groin or armpits headache muscle pains possible conjunctivitis shortness of breath fever chills sweating weight loss joint stiffness

 ◦ The goal of treatment is to

eliminate the infection with antibiotic therapy. Streptomycin and tetracycline are commonly used in this infection.

◦ Tularemia is fatal in about 5% of untreated cases and in less than 1% with treatment.

Complications   ◦ meningitis ◦ pneumonia ◦ pericarditis

Cat scratch disease is an infectious illness caused by the bacteria Bartonella, believed to be transmitted by cat scratches, bites, or exposure to cat saliva.

More than 40,000 cases occur annually in the US

Symptoms    ◦ A history of contact with a cat◦ Papule or pustule at site of

injury (inoculation), usually the first sign

◦ Swelling of the lymph nodes (adenopathy) occurs in the area near where the skin was infected (bitten, scratched, etc.)

◦ Fever in approximately one third of patients

◦ Fatigue◦ Malaise ◦ Headache

Treatment   ◦ Generally, cat scratch

disease is not serious. Treatment, other than reassurance, is not usually recommended. However, in severe cases treatment with antibiotics can be helpful.

Typhus is a rickettsial disease caused by one of two organisms, Rickettsia prowazekii (epidemic typhus and Brill disease) and Rickettsia typhi (murine or endemic typhus). Epidemic typhus and Brill disease are uncommon in the United States.

Murine typhus occurs in the southeastern and southern states. There are less than 100 cases per year. Murine typhus is a milder form and is seldom fatal (less than 2%).

It is frequently seen in the summer and fall and typically lasts two to three weeks. Risk factors for murine typhus include exposure to rat fleas or rat feces, or exposure to other animals (such as cats, opossums, raccoons, skunks, and rats).

Epidemic typhus occurs in poor hygienic conditions (which is why it is sometimes called "jail fever"), usually when the temperature is cold.

It is spread by lice. Although very rare in the United States, it has sometimes been spread by the lice and fleas of flying squirrels.

◦ severe headache ◦ fever, high (104 degrees Fahrenheit) ◦ cough in 70% of patients ◦ arthralgia and myalgia, (muscle pain)

severe ◦ chills ◦ falling blood pressure◦ stupor ◦ delirium◦ rash that begins on chest and spreads

to rest of trunk and extremities, but not to palms and soles

◦ early rash is faint and rose colored and fades with pressure (Later the lesions become dull, red, and do not fade. People with severe typhus may also develop petechiae.)

◦ lights appear very bright, and exposure to light may hurt the eyes

Treatment   ◦ The goal of treatment is to

eliminate the infection and to treat the symptoms with antibiotics (such as tetracycline, doxycycline, or chloramphenicol). For epidemic typhus, intravenous fluids and oxygen may be necessary to help stabilize the patient.

Prognosis   ◦ Without treatment death may

occur in 10 to 60% of patients with epidemic typhus. Patients over the age of 60 have the highest risk of death. With timely antibiotic therapy, the affected person is expected to recover completely.

◦ Less than 2% of untreated patients with murine typhus may die, and appropriate antibiotic therapy will cure virtually all patients.

An infectious disease caused by Rickettsia rickettsii transmitted to humans by the bite of ticks.

Symptoms   ◦ fever ◦ chills ◦ incubation period of 2 to 14 days ◦ severe headache ◦ muscle pain ◦ mental confusion ◦ rash, first appearing on wrists and

ankles, then spreading to most of the body, usually starts a few days after fever starts; up to 20% of people do not get a rash

Chagas disease is caused by Trypanosoma cruzi, a parasite related to the African trypanosome that causes sleeping sickness.

It is spread by reduvid bugs and is one of the major health problems in South America, where 20 million people are infected.

Due to immigration, approximately 500,000 people in the United States are believed to be infected.

Chagas disease has two phases – acute and chronic. The acute phase may have no symptoms or have very mild symptoms. Symptoms of the acute phase include swelling and reddening at the site of infection (where the blood-sucking insect caused the initial infection).

This may be followed by swelling of one eye. Lymph nodes that drain the area of the insect bite may become swollen. As the parasite spreads from the bite site, the patient develops fever, malaise, and generalized swelling of the lymph nodes. The liver and spleen may become enlarged.

The disease goes into remission after the acute phase and may become chronic with no further symptoms for many years. When symptoms finally develop, they appear as cardiac disease (cardiomyopathy) and digestive abnormalities.

Patients may developcongestive heart failure.

Swallowing difficulties may be the first symptom of digestive disturbances and may lead to malnutrition.

Patients who have parasitic infection of the colon may experience abdominal pain and constipation. Death is usually caused by heart disease.

  ◦ history of exposure in an area

where Chagas disease is known to occur

◦ swollen red area at site of previous insect bite

◦ enlarged lymph nodes ◦ swelling of one eye ◦ fever ◦ irregular heartbeat

(arrhythmia) ◦ rapid heartbeat (tachycardia) ◦ swallowing difficulties

Treatment   ◦ The acute phase should be treated.

Benznidazole has been shown to be effective. Experimental treatment may include nifurtimox. Treating the chronic phase with antibiotics is not helpful. Instead, the symptoms of heart and intestinal disease should be treated.

Prognosis   ◦ Approximately 30% of infected and

untreated people will develop chronic or symptomatic Chagas disease. It may take more than twenty years from the time of the original infection to develop heart or digestive problems.

◦ Abnormal heart rhythms (arrythmias, ventricular tachycardia) may cause sudden death. Once congestive heart failure develops, death usually occurs within several years.

Leishmania are tiny protozoa. Their parasitic life cycle includes the sandfly and an appropriate host.

Humans are one of those hosts. Leishmania infection can cause skin disease (called cutaneous leishmaniasis).

It can affect the mucous membranes with a wide range of appearance, most frequently ulcers. It may cause skin lesions that resemble those of other diseases including cutaneous tuberculosis, syphilis, leprosy, skin cancer (basal cell carcinoma), andfungus infections.

Symptoms    ◦ history of exposure to the bite of

sandflies ◦ history in being in an area known

for leishmaniasis ◦ Systemic illness (visceral

leishmaniasis) ◦ fever, persistent, long duration

(weeks), may cycle irregularly ◦ night sweats ◦ fatigue◦ weakness ◦ appetite loss (anorexia) ◦ weight loss ◦ abdominal discomfort, vague ◦ vomiting (children) ◦ diarrhea (children) ◦ cough (children) ◦ skin, scaly ◦ skin, gray, dark, ashen ◦ hair, thinning

Skin disease (cutaneous leishmaniasis)

Symptoms on the skin include: ◦ macule or papule,

erythematous ◦ skin ulcer, forms at site of

original lesion ◦ ulcer heals very slowly over

a matter of months ◦ smaller lesions may form

around the ulcer (satellite lesions)

Treatment   ◦ Antimony-containing compounds are

the principal medications used to treat leishmaniasis. These include: meglumine antimonate sodium stibogluconate

◦ Other drugs that may be used include: pentamidine amphotericin B Miltefosine

◦ Plastic surgery may be required to correct disfigurement by destructive facial lesions (mucocutaneous leishmaniasis). Removal of the spleen (splenectomy) may be required in drug-resistant cases (visceral leishmaniasis).

Causes and risks   ◦ Schistosoma infections are contracted

through contact with contaminated water. The parasite in its infective stages is called a cercaria. It swims freely in open bodies of water.

◦ On contact with humans, the parasite burrows into the skin, matures into another larval stage (schistosomula), then migrates to the lungs and liver (where it matures into the adult form).

◦ The adult worm then migrates to the anatomic area of its preference, depending on which species is involved. Likely areas include the bladder, rectum, intestines, liver, portal venous system, spleen, and lungs.

◦ Schistosomiasis is not usually found in the United States. However, it is prevalent in many tropical or subtropical areas, and it is a common illness thought to affect more than 200 million people.

Symptoms   ◦ Symptoms vary with the species of

worm and the phase of infection. ◦ Initial invasion of the skin may cause

itching and a rash (swimmer's itch). ◦ Heavy infestation may cause fever,

chills, lymph node enlargement, and liver and spleen enlargement.

◦ Urinary symptoms may include frequency, painful urination (dysuria), and blood in urine (hematuria).

◦ Intestinal symptoms include abdominal pain and diarrhea (which may be bloody).

Treatment   ◦ Praziquantel ◦ With acute infection,

corticosteroids may be given Prognosis   

◦ Treatment before significant damage or severe complications usually produces good results.

Toxoplasmosis is caused by the protozoan parasite Toxoplasma gondii. In the United States it is estimated that 22.5% of the population 12 years and older have been infected with Toxoplasma.

In various places throughout the world, it has been shown that up to 95% of some populations have been infected with Toxoplasma. Infection is often highest in areas of the world that have hot, humid climates and lower altitudes.

Toxoplasmosis is not passed from person-to-person, except in instances of mother-to-child (congenital) transmission and blood transfusion or organ transplantation. People typically become infected by three principal routes of transmission.

Foodborne transmissionThe tissue form of the parasite (a

microscopic cyst consisting of bradyzoites) can be transmitted to humans by food. People become infected by:

Eating undercooked, contaminated meat (especially pork, lamb, and venison)

Accidental ingestion of undercooked, contaminated meat after handling it and not washing hands thoroughly (Toxoplasma cannot be absorbed through intact skin)

Eating food that was contaminated by knives, utensils, cutting boards, or other foods that had contact with raw, contaminated meat

Cats play an important role in the spread of toxoplasmosis. They become infected by eating infected rodents, birds, or other small animals. The parasite is then passed in the cat's feces in an oocyst form, which is microscopic.

Kittens and cats can shed millions of oocysts in their feces for as long as 3 weeks after infection. Mature cats are less likely to shed Toxoplasma if they have been previously infected. A Toxoplasma-infected cat that is shedding the parasite in its feces contaminates the litter box. If the cat is allowed outside, it can contaminate the soil or water in the environment as well.

People can accidentally swallow the oocyst form of the parasite. People can be infected by:

Accidental ingestion of oocysts after cleaning a cat's litter box when the cat has shed Toxoplasma in its feces

Accidental ingestion of oocysts after touching or ingesting anything that has come into contact with a cat's feces that contain Toxoplasma

Accidental ingestion of oocysts in contaminated soil (e.g., not washing hands after gardening or eating unwashed fruits or vegetables from a garden)

Drinking water contaminated with the Toxoplasma parasite

People can accidentally swallow the

oocyst form of the parasite. People

can be infected by: Accidental ingestion of oocysts

after cleaning a cat's litter box when the cat has shed Toxoplasma in its feces

Accidental ingestion of oocysts after touching or ingesting anything that has come into contact with a cat's feces that contain Toxoplasma

Accidental ingestion of oocysts in contaminated soil (e.g., not washing hands after gardening or eating unwashed fruits or vegetables from a garden)

Drinking water contaminated with the Toxoplasma parasite

Most healthy people recover from toxoplasmosis without treatment. Persons who are ill can be treated with a combination of drugs such as pyrimethamine and sulfadiazine, plus folinic acid.

Pregnant women, newborns, and infants can be treated, although the parasite is not eliminated completely. The parasites can remain within tissue cells in a less active phase; their location makes it difficult for the medication to completely eliminate them.

Persons with ocular toxoplasmosis are sometimes prescribed medicine to treat active disease by their ophthalmologist. Whether or not medication is recommended depends on the size of the eye lesion, the location, and the characteristics of the lesion (acute active, versus chronic not progressing).

Persons with compromised immune systems need to be treated until they have improvement in their condition. For AIDS patients, continuation of medication for the rest of their lives may be necessary, or for as long as they are immunosuppressed.