Bacterial Pathogens Cocci of Medical Importance Genus Staphylococcus o Gram o Contains several dozen species o Facultative Anaerobe wide range of oxygen levels o Can cause disease in all places of the body o Major cause in nosocomial infections o Harder to kill off than other types of bacteria o Can survive for a long time on inanimate objects or fomites o Transmitted easily o 15 25 of all infections o 15 20 pneumonia Strain Variation of bacteria Staphylococcus Aureus Methicillin Resistant Staphylcoccus Aureus MRSA o Multiple drug resistant strain of staph aureus o Hard to get rid of once in clinical setting o More virulent o Special procedures needed to prevent spread o Out breaks are commonly found in locker rooms schools athletes etc Coagulase Negative Staphylococcus CoNS o Not as pathogenic virulent o Normal skin inhabitants o Surgical sites and indwelling devices Genus Streptococcus Fastidious needs growth factors vitamins Gram Not many strains are resistant Easier to kill than staphylococcus Does not persist or stay on fomites for long Streptococcus Pyogenes Causes wide variety of disease Reproductive tract Skin infections o Puerperal Fever Woman die a few days after child birth due to complications Strep Throat Complications o Rheumatic Fever Joints become inflamed especially in the lining of the heart and heart valves After recovery heart valves still fail later in life o Scarlet Fever Toxin released causes fever and bright red rash o Glomerulonephritis Kidney damage failure Streptococcus Pneumoniae pneumococcus 5 50 of people normal nasopharynx flora Pneumococcal pneumonia o Infection in the lungs o 70 of all bacterial pneumonia o Most deaths in the elderly o Meningitis Sputum Mucus coughed up from the lungs Otis Media Infection of middle ear Inflamed ear drum 30 40 of cases due to Strep Pneumoniae Penicillin and amoxicillin used for treatment 17 resistance in S pneumonia Cocci of Medical Importance Genus Enterococcus Shows up more in hospitals Intestinal tract commensals large intestines Gram Growing cause of nosocomial infections 16 UTIs Has natural resistance to antibiotics and may transfer their resistance to Long lasting in environment more serious diseases VRE Genus Neisseria Gram Comes in pairs and is bean shaped Diplococci Fastidious and requires CO2 and a lot of growth factors vitamins o Neisseria gonorrheoae STD Most common STD Symptoms Males Over 300 000 cases per year in the USA 1 Develop quickly after transmission 2 80 of men will develop symptoms 3 Painful urination Urethritis Symptoms Females 4 Not likely to have long term effects 1 Very mild symptoms but spreads to other organs 2 50 see symptoms 3 Urethritis vaginitis cervicitis 4 If spreads deeper it can lead to PID pelvic inflammatory 5 Can lead to damage to the fallopian tubes and can cause disease infertility Treatments Antibiotics penicillin or cephalosporin tetracycline Can lead to Gonococcal Ophthalmia Infection of the outer lining of eyes in infants that is passed from the infected mother o Neisseria meningitides meningococcal meningitis Most serious form of the disease in the meninges Starts growing in the lining of the brain then releases the endotoxin LPS Endotoxin then invades the bloodstream and spread to other organs other than the brain Many people have natural immunity Common in children and teens and crowded cities Bacteria is usually inhaled by the person then infects nasal Spread through direct contact cavity travels through porous bone and finally infects meninges in the brain Symptoms Prodromal Symptoms then rapidly increases Headache stiffneck fever delirium convulsions hemorrhaging 15 mortality with treatment If caught early full recovery is possible if not loss of limbs or kidney failure can happen Treatments Penicillin G Prevention vaccine for high risk groups or prophylactic Preventative antibiotics for people that came in contact Bacilli of Medical Importance Genus Clostridium Most harmless fermenters that survive in little to no oxygen o Gram o Anaerobic o Forms resistant endospores o Grows on dead or decaying matter in soils or water saprophytic o Some are commensals in intestinal tract some are potent toxins Gas Gangrene Caused by several different species of clostridium c perfringens is most common o Infections of serious wounds often deep and contaminated with debri dirt or dust o Often in surgical sites o Bacterium produce toxins and enzymes that produce gas o Endospores get into the wound deep where there is no oxygen and replicate in tissue and release fermented end products of CO2 gas o Subcutaneous and muscle tissue destroyed Treatments Broad spectrum cephalosporins penicillin Debridement surgical removal of dead tissue Amputation Removal of limb to stop from spreading Hyperbaric oxygen therapy put in a chamber that pumps high levels of oxygen o Disease is fatal if spreads to body cavities Prevention Clean wounds Prophylactic antibiotics preventative Tetanus C tetani Wound infections and toxicosis disease due to toxin Pathogenesis Description of how the disease progresses o Endospores invade deep puncture wounds o Vegetative cells develop and produce potent toxin o Tetanospasmin a neurotoxin in spinal cord o Toxin gets into blood steam then spinal cord and effects nerves in o Binds to inhibitory motor neurons and slows down impulses from spinal cord reaching skeletal muscles o Skeletal muscles over contract to the point where you cant move your muscles and you face paralysis o Symptoms Painful spastic paralysis of skeletal muscles Tense contractions of muscles Neck face and limbs them reaches respiratory muscles Leads to difficulty swallowing or breathing Death due to respiratory failure because the breathing muscles are paralyzed o Treatments Antibiotics although no effect of toxins already released Passive immunization human tetanus immune globin binds up inactive bacteria Have to do both treatments to be successful o Prevention Active immunization tetanus toxoid very effective