1. General Infectious Disorders Part 2 Common Bacterial Infections
In this lecture we will discuss common bacterial infections

2. Examples of Bacterial Infections (General)
Group A Streptococcus Infections
A bacterium commonly found in the throat & skin resulting in a range of potential diseases from mild to deadly:
1. Strep throat
2. Scarlet fever
3. Rheumatic fever
4. Impetigo
5. Necrotizing fasciitis
Prevention involves hand-washing; clinician attention for those with sore throats with isolation of strep + individuals until 24 hours after starting antibiotics; cleansing of all wounds with careful attention to redness, swelling or drainage.
One of the most common bacterium causing infections in humans is the streptococcal bacterium. There are many strains, but the most common is Group A Streptococcus infections. This bacterium is commonly found in the throat and skin resulting in a range of potential diseases that range from mild to deadly. These include: Strep throat, scarlet fever, rheumatic fever, impetigo, and necrotizing fasciitis.

3. Examples of Bacterial Infections (General)
Staphylococcyl Infections
Toxic shock syndrome (TSS)
S. aureus commonly colonizes skin and mucous membranes in humans.
TSS has been associated with use of tampons and intravaginal contraceptive devices in women and occurs as a complication of skin abscesses or surgery.
Staphylococcal infections are responsible for many common skin infections and food poisoning. They also cause Toxic Shock Syndrome, or TSS. TSS is usually associated with tampon use and contraceptive devices, but it may also be caused by surgery or skin abscesses.

4. Examples of Bacterial Infections (General)
Staphylococcal Infections
Toxic shock syndrome (TSS)
In the United States, annual incidence is 1-2/100,000 women years of age (last active surveillance done in 1987).
5% of all cases are fatal.
Toxic shock syndrome (TSS) is characterized by sudden onset of fever, chills, vomiting, diarrhea, muscle aches and rash.
It can rapidly progress to severe and intractable hypotension and multisystem dysfunction. Desquamation, particularly on the palms and soles can occur 1-2 weeks after onset of the illness.
TSS is a relatively rare disease that has somewhat non-specific symptoms. The individual with TSS may suffer from hypotension and multisystem dysfunction.

5. Impact on lowering tampon absorbency rate TSS cases
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This graph shows the impact that lowering the absorbency of tampons has on the rate of TSS cases.
Source:

6. Examples of Bacterial Infections (General)
Staphylococcyl Infections
Methicillin-resistant Staphylococcus Aureus (MRSA)
Methicillin-resistant Staphylococcus Aureus (MRSA) is a type of staph that is resistant to certain antibiotics.
Staph infections, including MRSA, occur most frequently among persons in hospitals and healthcare facilities (such as nursing homes and dialysis centers) who have weakened immune systems.
MRSA infections in the community are usually manifested as skin infections, such as pimples and boils, and occur in otherwise healthy people.
Invasive MRSA infections that began in hospitals declined 28% from 2005 through 2008.
Staph that is resistant to Methicillin and other antibiotics is called Methicillin-resistant Staphylococus Aureus or MRSA. These infections occur most frequently among persons staying in hospitals or other healthcare facilities who have weakened immune systems. MRSA can also occur in the community and has been seen in healthy children and adults who do not have hospital-associated risk factors.

7. S. Aureus Infection
Most infections caused by S. aureus are skin and soft tissue infections
MRSA has been reported in increasing numbers among healthy persons of all ages
This is referred to as Community Acquired MRSA
Skin-to-skin contact with someone who has MRSA, someone with open cuts or abrasions, or someone who has poor hygiene or participates in contact sports is more likely to get MRSA. MRSA that is acquired in persons without the hospital associated risk factors is called Community Acquired MRSA.

8. MRSA
Treatment
Both hospital and community associated strains of MRSA still respond to certain medications. In hospitals and care facilities, doctors generally rely on the antibiotic vancomycin to treat resistant germs. CA-MRSA may be treated with vancomycin or other antibiotics that have proved effective against particular strains.
MRSA is more difficult to treat, but not impossible. Doctors generally use the antibiotic vancomycin to treat MRSA. This is given through injection or intravenous drip. Surgery may be needed to remove infected tissue or implanted devices that have become infected.

9. Methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA) Among ICU Patients, 1995-2004
This graph shows that MRSA has been gradually increasing among ICU patients.
Source: National Nosocomial Infections Surveillance (NNIS) System

10. Examples of Bacterial Infections (General)
Tuberculosis
Causative agent: Mycobacterium tuberculosis
Epidemiology
Third leading cause of death in 1900
One third of the World’s population is infected with TB
Almost 10,000 TB cases were reported in the US in 2012 (3.2 cases per 100,000)
In 2012, 63% of TB cases occurred among foreign-born persons. This is 11 times higher than in US-born persons.
Without intervention, about 10% will develop TB disease at some point in life
Development of antibiotics in the 1950’s dramatically reduce rates
From 1985 to 1992, reported TB cases increased by 20%
Since 1993, reported TB cases have been declining again
Today, one third of the World’s population is infected with TB. In the US, 9,945 cases were reported in 2012, which is the lowest number of reported cases since national reporting began in Rates of TB have been declining since the 1992 resurgence peak. In 2012, 63% of TB cases in the US occurred among foreign-born persons, which is eleven percent higher than the rate among US-born persons.

11. Symptoms Symptoms of TB include: A bad cough lasting 3 weeks or longer
Weight loss
Chills
Fever
Night sweats
Pain in the chest
Coughing up blood
Weakness/fatigue
Only a small percentage of those who have been exposed to TB will develop TB, and of those, only a small percentage will show symptoms.

12. Examples of Bacterial Infections (General)
Tuberculosis
Pathogenesis / Transmission
Only 5-10% of these will ever develop symptoms
50% in the first year / 50% after the first year
TB is primarily an airborne disease that spreads through microscopic droplets when the infected person sneezes, coughs, laughs, or speaks.
Only a small percentage of those infected with TB will show symptoms. TB is primarily an airborne disease that is spread through microscopic droplets.

13. Examples of Bacterial Infections (General)
Tuberculosis
Pathology
PNM’s attempt to destroy
Macrophages invade and combine w/ destroyed tissue to create tubercle
May become calcified / walled off
Lung function may become impaired if immune the system cannot cope and damage spreads
May spread to other areas of the body and linger for years
Treatment
Six months to one year of antibiotic therapy
Tb is caused my a immune response in which the PNM’s attempt to destro the lung tissue. Macrophages then invade and combine with the destroyed tissue to create a tubercle. This area will become walled-off and calcified and lung function may become impaired. Treatment of TB can involve as little as six months and up to one year of antibiotic therapy.

14. TB Case Rates in U. S. -born vs
TB Case Rates in U.S.-born vs. Foreign-born Persons, United States, 1993 – 2012*
Cases per 100,000
This slide depicts the difference in rates of TB among foreign-born persons versus US-born persons.
*Updated as of June 10, 2013.

15. As you can see in this graph, the rate of reported cases of TB has generally been decreasing in the past decade.

16. From this chart, you can see that the number of cases of TB has been decreasing every year. TB morbidity is the number of cases per 100,000.

17. This pie chart shows the differences in reported cases of TB among various races or ethnicities.

18. Pneumonia
An infection of the terminal airways of the lungs involving the respiratory bronchioles, alveolar ducts and sacs, and alveoli
Infection of the lung as manifested by:
Fever
Cough
Clinical signs of consolidation
Hypoxemia
New CXR (chest x-ray) infiltrate
Most types of pneumonia can be treated with an antibiotic, but it may be a serious illness for those who are elderly or already ill. Pneumonia can cause problems for those younger than 2 and older than 65.

19. Pneumonia CAUSES OF PNEUMONIA
Pneumonia is not a single disease. It can have over 30 different causes. There are five main causes of pneumonia:
Bacteria
Viruses
Mycoplasmas
Other infectious agents, such as fungi -- including pneumocystis
Various chemicals
Pneumonia kills more people each year in the US than all other vaccine-preventable diseases combined. Pneumonia has other 30 different causes, and half of all pneumonia cases are believed to be caused by viruses. The main 5 causes are listed.

20. Pneumonia
Pneumonia is often divided into two main categories ('community-acquired pneumonia' and 'hospital-acquired pneumonia') depending on whether you were infected while living at home (in the community) or while staying in hospital.
Pneumonia is often divided into community-acquired and hospital-acquired depending on whether the the person was infected in or outside of a hospital setting.

21. Pneumonia
Treatment
Most cases of pneumonia can be treated without hospitalization. Typically, oral antibiotics, rest, fluids, and home care are sufficient for complete resolution. However, people with pneumonia who are having trouble breathing, people with other medical problems, and the elderly may need more advanced treatment.
Pneumonia is typically treated with oral antibiotics, rest, and fluids. Those who are having trouble breathing, those with other medical problems, or the elderly may need more advanced treatment.