Bacterial infection(classifications accordung to disease).pptx

This lecture discusses the types of bacteria in different disease(pneumonia, meningitis..etc)

1. Bacterial infection Dr Asma Alsherei ق

2. Bacteria Prokaryotes (pro-carry-oats) . DNA is not enclosed in a nucleus. Classification: Gram Stain Morphology Oxygen tolerance Spore formation The domain Bacteria also includes rickettsiae , chlamydiae , mycoplasmas, actinomycetes , Nocardia spp., and mycobacteria. Except for mycoplasmas, bacteria are enclosed in a peptidoglycan-containing cell wall

3. Febrile Patients at Increased Risk for Serious Bacterial Infections ( Immunocompetent) Condition Comment Neonates (<28 d) Sepsis and meningitis caused by group B streptococci, Escherichia coli , Listeria monocytogenes , herpes simplex virus Infants <3 mo Serious bacterial disease (10-15%); bacteremia in 5% of febrile infants Infants and children 3-36 mo Occult bacteremia in 4%; increased risk with temperature >39°C and white blood cell count >15,000/muL Hyperpyrexia (>41°C) Meningitis, bacteremia, pneumonia, heatstroke, hemorrhagic shock-encephalopathy syndrome Fever with petechiae Bacteremia and meningitis caused by Neisseria meningitidis , Haemophilus influenzae type b, Streptococcus pneumoniae

4. Progression from infection to sepsis (SIRS) and its complications

5. Treatment Lab: cultures, CBC, PT, PTT, fibrinogen level, ABGs, and CXR. Airway: O2, PEEP, ventilation Circulation: IV crystalloids, colloids IV ABx: Bactericidal, 3 rd G cephalosporin, +/_ aminoglycoside. Inotropes: e.g. dopamine, epinephrine, dobutamine Corticosteroids: improve the hearing outcome of children with meningitis caused by HiB and in Waterhouse-Friderichsen syndrome

6. Clinical Syndromes: Bacterial Meningitis first 2 mo : GBS , gram-negative enteric bacilli, and Listeria monocytogenes occasionally H. influenzae (any) 2 m-12 y : S. pneumoniae, N. meningitidis, or H. influenzae type b. Alterations of host defense (anatomic defects or immune deficits) : less common pathogens e.g. Pseudomonas aeruginosa, Staphylococcus aureus, CONS, Salmonella spp, and L. monocytogenes. Treatment : Bactericidal ABx (3 rd G Ceph. + Vancomycin in USA) Data support the use of intravenous dexamethasone , 0.15 mg/kg/dose given every 6 hr for 2 days, (age > 6 wk) especially for H. influenzae type b.

7. Febrile Patients at Increased Risk for Serious Bacterial Infections ( Immunocompromized) Condition Comment Sickle cell anemia Pneumococcal sepsis, meningitis Asplenia Encapsulated bacteria Complement/properdin deficiency Meningococcal sepsis Agammaglobulinemia Bacteremia, sinopulmonary infection AIDS S. pneumoniae , H. influenzae type b, Salmonella Congenital heart disease Increased risk of endocarditis Central venous line Staphylococcus aureus , coagulase-negative staphylococci, Candida Malignancy Gram negative enteric bacteria, S. aureus , coagulase-negative staphylococci, Candida

8. Preceding viral infection disturbs the defense mechanisms of the lungs. S. pneumoniae is still the most common cause of bacterial infection of the lungs. Streptococcal pneumonia and tracheobronchitis are uncommon, viral infections particularly those causing exanthems and epidemic influenza, predispose to these diseases, which are encountered most frequently in children 3-5 yr of age. Staphylococcal Pneumonia : < 1y age, rapid progression of symptoms, H. influenzae pneumonia is more often insidious in onset, and the course is usually prolonged over several weeks , usually lobar in distribution . Clinical Syndromes: Bacterial Pneumonia

9. Clinical Syndromes: Gastroenteritis Organism Antimicrobial Agent Indication for Antimicrobial Therapy Aeromonas TMP/SMX Dysentery-like illness, prolonged diarrhea Campylobacter Erythromycin * Early in the course of illness Clostridium difficile Metronidazole or vancomycin Moderate to severe disease Escherichia coli   Enterotoxigenic TMP/SMX * Severe or prolonged illness   Enteropathogenic TMP/SMX Nursery epidemics, life-threatening illness   Enteroinvasive TMP/SMX * All cases if organism susceptible Salmonella Ampicillin or chloramphenicol or TMP/SMX or cefotaxime * Infants <3 mo, immunodeficient patients, typhoid fever ( Salmonella typhi ), bacteremia, dissemination with localized suppuration Shigella TMP/SMX; cefixime or ceftriaxone for resistant strains * All cases if organism susceptible Vibrio cholerae Tetracycline or doxycycline All cases

10. Clinical Syndromes: OM & SA Osteomyelitis: Staphylococcus aureus (all age groups) GBS and gram-negative enteric bacilli (neonates). GAS < 10% of cases. After 6 yr of age, gram-positive cocci or Pseudomonas aeruginosa (puncture wounds of the foot). Suppurative arthritis : staphylococcal infection (most common). Haemophilus influenzae type b (accounted for more than half of all cases before widespread vaccination) Invasive GAS & Strept. pneumoniae