抗生素的应用（英文ppt）课件

Case #1,An 8-year-old boy is seen in February because of fever, headache, sore throat, and malaise. Hes had no rhinorrhea, cough, or hoarseness. Physical examination reveals a temperature of 103.5, exudative pharyngitis, and tender cervical adenopathy. How will you treat him?,Is penicillin still the drug of choice for treatment of streptococcal pharygitis?,AAP recommends oral penicillin V 2-3 times daily for 10 days, a single dose of benzathine penicillin, or amoxicillin 250 mg/kg tid for 10 days Larger doses of penicillin once daily result in more relapses* *Breese, 1965, Gerber, 1989,Once daily dosing?,Recommended by the FDA: azithromycin (Zithromax) cefixime (Suprax) cefdinir (Omnicef) cefadroxil (Ultracef, Duracef) ceftibutin (Cedax) Amoxicillin (750 mg once daily)* *Feder, Pediatrics, 1999,Shorter courses?,Approved by the FDA for 5-day regimen: cefpodoxime (Vantin) cefdinir (Omnicef) azithromycin (Zithromax),What about the penicillin-allergic child?,Erythromycin estolate (20-40 mg/kg/d divided bid) or ethylsuccinate (40 mg/kg/d divided bid) Azithromycin (12 mg/kg/d x 5 d), clarithromycin (15 mg/kg/d div q 12 hrs), clindamycin (20 mg/kg/d div q 6-8 hrs),Why penicillin might “fail”,Non-adherance to prescribed therapy failure to recognize carriers ? beta-lactamase production by other pharyngeal flora new streptococcal infection,Case #2,A 13-year-old boy has had fever and sore throat for two days. He now presents with a cough. On examination he has a temperature of 104, RR 22, O2 saturation of 98%, retractions, and crackles over the posterior left lower lung. Chest x-ray confirms a left lower lobe pneumonia. What do you think is causing his pneumonia? How will you treat him?,Common Causes of Community-Acquired Pneumonia in Otherwise Healthy Children,Viruses Respiratory syncytial virus Influenza A and B Parainfluenza 1, 2, and 3 Adenovirus Rhinoviruses Measles virus Mycoplasma Mycoplasma pneumoniae Chlamydia Chlamydia pneumoniae Chlamydia trachomatis,Bacteria Streptococcus pneumoniae Mycobacterium tuberculosis Staphylococcus aureus Haemophilus influenzae type b non-typable H. influenzae,McIntosh,K: NEJM 2002;346:429,Likelihood that the pneumonia is bacterial is greater if:,Fever is 39 degrees C The patient “looks sick” There are alveolar infiltrates on chest x-ray WBC is 15,000 NB: Blood culture is positive in about 10% of infants and children with bacterial pneumonia and more likely in those 2 yrs,Bacterial pneumonia according to age:, 28 days: Group B streptococcus, Gram negative enterics, CMV, listeria 3 wks - 3 months: C trachomatis, RSV, parainfluenza, S. pneumoniae, B. pertussis, Staph aureus 4 months-4 years: respiratory viruses, S. pneumoniae, M. pneumoniae, H. influenzae, TB 5 - 15 years: M. pneumoniae, S. pneumoniae, C. pneumoniae, TB,Antibiotics for pneumonia-according to age:, 28 days: ampicillin and gentamicin 1 month - 3 months: macrolide (afebrile) + cefotaxime/ceftriaxone (fever) 4 months - 4 years: NO ANTIBIOTICS FOR VIRAL INFECTION Amoxicillin (80-100 mg/kg/d divided tid) OR ampicillin 200 mg/kg/d divided q 6 hrs, OR cefuroxime or cefotaxime 5 - 15 years: macrolide + IV ampicillin OR cefuroxime OR cefotaxime,Beta-lactam-resistant S. pneumoniae:,Intermediate resistance: MIC = 0.1-1 microgram/ml High level resistance: MIC 2 micrograms/ml 100,000 units/kg of penicillin G yields a serum concentration of about 10 micrograms/ml 500 mg of amoxicillin yields a serum concentration of about 8 micrograms/ml,Importance of beta-lactam-resistant S. pneumoniae:,Highest risk in children 3 years day care recent antibiotics Can be overcome by high doses of penicillin/ampicillin Impact of Prevnar for immunized children? 11% fewer episodes of pneumonia, 33% fewer with abnormal x-ray, 73% fewer with extensive disease,What if his RR was 35, his O2 saturation was 85% and he had an effusion on chest x-ray?,Dont forget Staphylococcus aureus and group A streptococcus in children with large effusions who look very sick. IV clindamycin should be added for these children.,Case #3,A two-month-old girl is brought to your office because of a 5-day history of rhinorrhea and cough. She has been afebrile. On exam she has rhinorrhea and coughs frequently. There are scattered crackles and wheezes throughout her lung fields. What is the cause of her respiratory symptoms? How will you treat her?,Antibiotics for pneumonia-according to age:, 28 days: ampicillin and gentamicin 1 month - 3 months: macrolide (afebrile) + cefotaxime/ceftriaxone (fever) 4 months - 4 years: NO ANTIBIOTICS FOR VIRAL INFECTION Amoxicillin (80-100 mg/kg/d divided tid) OR ampicillin 200 mg/kg/d divided q 6 hrs, OR cefuroxime or cefotaxime 5 - 15 years: macrolide + IV ampicillin OR cefuroxime OR cefotaxime,Think about,Pertussis Any contacts with cough illness? Is the cough paroxysmal? Chest x-ray-pertussis only rarely is associated with pulmonary infiltrates CBC to look for lymphocytosis Chlamydia Maternal history of chlamydia?,And think about,Viruses Contacts? Season? (RSV, influenza, parainfluenza, enteroviruses) Antibiotic? The only class that makes sense is macrolides-erythromycin estolate, clarithromycin, azithromycin,Case #4,A four-year-old girl has had rhinorrhea, cough, and intermittant fever for 12 days. Her mom thinks there has been no improvement in her symptoms during that time. On exam she has a temperature of 100.5, rhinorrhea, and cough. What is your diagnosis?,AAP Clinical Practice Guideline (September, 2001),Diagnose acute sinusitis based upon persistent symptoms, no need for radiologic studies Treat with antibiotics as per acute otitis media recommendations BUT. . . .,Findings from Garbutt,JM, et al: Pediatrics: 2001;107:619 in a study of 161 patients 1-18 years old (50% 7 yrs) with symptoms between 10-28 days,Criticism of Garbutt study:,Children included were only mildly ill Diagnosis wasnt confirmed by x-ray Inclusion of older children whose disease was likely mild Symptomatic therapy was permitted Antibiotic doses prescribed may have been inadequate,Wald (letter):Pediatr 2002;109:166,Case # 5,A 6-year old girl developed varicella 7 days ago. She had fever for the first 4 days of her illness. Fever resolved but returned 1 day ago. Now she complains of pain in her left leg. On exam she has a temp of 102.5, scabbed varicella lesions over her trunk, face, and extremities, and tenderness over her left ankle region. There is also redness and tenderness around one of the scabbed lesions on her abdomen. What is your major concern?,MMWR;1997:46:944,Cases of varicella at a childcare center, by date of onset-Boston, MA January-February 1997,Cases of group A streptococcus at a childcare center by date of onset- Boston, MA, January-February, 1997,Bacterial complications associated with varicella:,Treat for group A streptococcal infection, but keep Staphylococcus aureus in mind.,Case # 6,An 18-month-old girl presents with continuing symptoms after 4 days of treatment with amoxicillin for acute otitis media. She is still complaining of ear pain, she has a temperature of 38.8 degrees C., and she is irritable. On exam you find that her TM is white and bulging with decreased mobility. What is/are the likely cause(s) of her persistent findings? How will you treat her?,Appropriate questions:,What dose of amoxicillin was prescribed? Did she take it? What is the likelihood of infection with resistant pneumococcus? What other bacteria do you want to treat?,Risk that this infection is due to S. pneumoniae: Acute otitis media due to S. pneumoniae is least likely to resolve spontaneously Risk factors for infection with resistant S. pneumoniae: 3 years day care attendance,Treatment options:,Continue current therapy (there is no direct relationship between the persistence of symptoms and the viability of infecting bacteria) Increase amoxicillin to 80-90 mg/kg/day (increase activity against resistant S. pneumoniae) Increase activity against beta-lactamase-producing organisms (H. influenzae and M. catarrhalis),Enhanced treatment against beta-lactamase-producers:,Add clavulanate (could also enhance activity against resistant S. pneumoniae by increasing amoxicillin component) Alternate choices: cefdinir (Omnicef), cefuroxime axetil (Ceftin), IM ceftriaxone (Rocephin), azithromycin (Zithromax),Other approaches:,Enhance compliance: reduced daily dosing, better taste, parenteral (ceftriaxone) therapy Tympanocentesis and culture,Case # 7,A 2-month old boy (born at term) is brought to the ED because of fever, irritability, and poor feeding for the past 24 hours. On exam the infant has a temp of 101, RR 50, O2 saturation 95%. He is moderately irritable, but his exam is otherwise normal. How will you evaluate and treat him?,After blood, urine, and CSF cultures have been obtained. . .,Treatment should be aimed at which bacterial organisms? S. pneumoniae Group B streptococcus H. influenzae E. coli and other enterics, incl salmonella Listeria,Whats wrong with ampicillin and gentamicin?,Nothing, as long as the CSF doesnt reveal pleocytosis. If it does, use ampicillin and ceftriaxone/cefotaxime (and consider vancomycin pending cultures),Case # 8,A 15-year-old boy was wrestling with his neighbors dog and was bitten on the arm. On exam he has a 2 cm jagged laceration on his right forearm. What are the bacterial agents to consider? What antibiotic(s) will you use?,Bacteria: Staphylococcus aureus (amp plus clav) Pasturella multocida (penicillin/ampicillin) Eikenella corrodens (ampicillin) Streptococcus and Staphylococcus species Dont forget to wash the wound and give tetanus prophylaxis if indicated,A 14-year-old girl is brought to the pediatric ED after 18 hours of