bacterial diseases

beneficial gut microbiome

• at birth: entire intestinal tract is sterile

• infant gut colonized by maternal environmental bacteria during birth and through feeding & other contacts

• by age 2.5 yrs the microbiota is similar to that of an adult, with variety of bacterial species

• flora is influences by age, diet, socioeconomic conditions

• antibiotics have potential to profoundly impact the microbiota

• microbiota help protect the host from colonization by pathogenic species

effect on humans

• most bacteria dont cause disease in humans

• beneficial bacteria: microbiome in the body can help prevent growth of other more dangerous bacteria

• pathogenic bacteria: cause disease

effect on oxygen

• aerobic bacteria need oxygen

• anaerobic bacteria have trouble living/growing in presence of oxygen

• facultative bacteria can live/grow with or without oxygen

staining, gram staining

• differences in staining are due to diff in cell wall

• gram positive & gram negative bacteria cause diff types of infections and r treated with diff types of antibiotics

• positive: stain blue/purple

• negative: stain red/pink

shape

• sphere (cocci)

• rods (bacilli)

• spirals or helixes (spirochetes)

• susceptibility to specific antibiotics

pertussis (whopping cough)

• caused by bacterium Bordetella pertussis

• attach to cilia and release toxins that damage the cilia and cause airways to swell

• highly contagious, airborne transmission by coughing or sneezing

• babies are highly susceptible

• vaccine preventable

helicobacter pylori (H pylori)

• in feces, saliva, and plaque on the teeth

• common worldwide

• transmissible through kissing or other close contact

• bacteria protect themselves by:

  • grow mucus layer stomach lining (protected from stomach acid)

  • producing ammonia (helps protect stomach acid; facilitates penetration of mucus layer

• increases acid production interferes with stomachs normal protection from acid and produces toxins

• effects:

  • inflammation of the stomach lining

  • peptic ulcer disease

  • some types of stomach cancer

• symptoms:

  • indigestion

  • pain & discomfort in upper abdomen

staphylococcus aureus

• spread by:

  • skin-to-skin contact

  • from contaminated surfaces or shared personal items including towels, soap & sports equipment

• can cause:

  • skin infections

  • bacteria in the blood and sepsis

  • pneumonia

  • endocarditis (infection of the heart valves) which can lead to heart failure or stroke

  • osteomyelitis (bone infection) due to bacteria in bloodstream

• ppl with diabetes or cancer - greater risk of staph infection

preventing transmission from contaminated surfaces: practicing good hand hygiene

• good hand hygiene breaks the chain of infection at the mode of transmission

• compliance with good hand hygiene is still a problem among healthcare workers

  • handwashing olympics

tuberculosis (TB)

• globally one of the most important causes of death due to infectious disease

• seen in all countries

• each yr about 9 mil ppl develop active Tb and 1.5 mil die of TB

• among frequent causes of death in females aged 15 to 44

• responsible for one-third of all HIV related deaths

TB caused by

• mycobacterium tuberculosis (has characteristics of both gram positive and gram negative bacteria)

• transmission occurs through the air a person with active TB coughs, speaks, sneezes

• latent Tb infection (no symptoms, not contagious)

• active tb: causes illness usually contagious: can occur weeks or years after infection

  • coughing

  • chest pain

  • unintentional weight loss

  • fatigue

  • fever, night sweat, chills

  • loss of appetite

active TB

• pulmonary

  • 85% cases

  • contagious

  • persistent cough

• extra pulmonary

  • kidney

  • spine

  • brain

  • symptoms can vary according to organs involved

ppl at higher risk of TB infection

• those around ppl with TB disease

• country where TB is common (latin america, africa, asia, eastern europe, russia)

• spend time in high risk settings, correctional facilities, nursing homes, homeless shelters

• HIV infection

• ppl who inject illegal drugs

• babies, young children, elderly

TB is not spread by

• shaking someone’s hand

• sharing food or drink

• touching bed linens or toilet seats

• sharing toothbrushes

• kissing

TB - good & bad news

• only 5% exposed get sick

  • airborne

  • a person with active TB will infect 10-15 persons per year

• curable-treatable

  • antibiotics

  • tough regimen

• multidrug-resistant TB (MDR TB): resistant at least to isoniazid & rifampin (the 2 most potent TB drugs)

• extensively drug-resistant TB (XDR TB): resistant to nearly all drugs used to treat TB

Detecting TB

• Hero Rats detect TB

• and they get rewarded when the get it correct