抗生素的应用(英文PPT).ppt

1、抗生素的应用(英文PPT)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*Bre

2、ese,1965,Gerber,1989Once daily dosing?Recommended by the FDA:azithromycin(Zithromax)cefixime(Suprax)cefdinir(Omnicef)cefadroxil(Ultracef,Duracef)ceftibutin(Cedax)Amoxicillin(750 mg once daily)*Feder,Pediatrics,1999Why penicillin might“fail”Non-adherance to prescribed therapy failure to recognize car

3、riers?beta-lactamase production by other pharyngeal flora new streptococcal infectionCase#2A 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

4、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 ChildrenVirusesRespiratory syncytial virusInfluenza A and BParainfluenza 1,2,and 3AdenovirusRhinovirusesMea

5、sles virusMycoplasmaMycoplasma pneumoniaeChlamydiaChlamydia pneumoniaeChlamydia trachomatisBacteriaStreptococcus pneumoniaeMycobacterium tuberculosisStaphylococcus aureusHaemophilus influenzae type bnon-typable H.influenzaeMcIntosh,K:NEJM 2002;346:429Likelihood that the pneumonia is bacterial is gre

6、ater 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 yrsBacterial pneumonia according to age:28 days:Group B streptococcus,

7、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,TBAntibiotics for pneumonia-according to age:2 mic

8、rograms/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/mlImportance of beta-lactam-resistant S.pneumoniae:Highest risk in children 3 years day care recent antibiotics Can be overcome

9、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 diseaseWhat 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

10、A streptococcus in children with large effusions who look very sick.IV clindamycin should be added for these children.Case#3A 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 a

11、re 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 ANTIBIO

12、TICS 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 cefotaximeThink about Pertussis Any contacts with cough illness?Is the cough paroxysmal?Chest x-ray-pertussis only

13、 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,azit

14、hromycinCase#4A 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,20

15、01)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 symptomsbetween 10-28 daysCrit

16、icism 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 inadequateWald(letter):Pediatr 2002;109:166Case#5A 6-year old girl de

17、veloped 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

18、 is also redness and tenderness around one of the scabbed lesions on her abdomen.What is your major concern?MMWR;1997:46:944Cases of varicella at a childcare center,bydate of onset-Boston,MA January-February1997Cases of group A streptococcus at achildcare center by date of onset-Boston,MA,January-Fe

19、bruary,1997Bacterial complications associated with varicella:Treat for group A streptococcal infection,but keep Staphylococcus aureus in mind.Case#6An 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

20、 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

21、?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

22、 care attendanceTreatment 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-pro

23、ducing 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),az

24、ithromycin(Zithromax)Other approaches:Enhance compliance:reduced daily dosing,better taste,parenteral(ceftriaxone)therapy Tympanocentesis and cultureCase#7A 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

25、 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

26、 other enterics,incl salmonella ListeriaWhats 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#8A 15-year-old boy was wrestling with his neighbors dog and was b

27、itten 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 Staphylococc

28、us species Dont forget to wash the wound and give tetanus prophylaxis if indicatedA 14-year-old girl is brought to the pediatric ED after 18 hours of fever.She had complained of sore throat and headache,and went to bed early the night before.This morning her mother found her in the bathroom somewhat

29、 disoriented.She had vomited once and had an episode of diarrhea the night before.On exam she had a temp of 103,RR 25,O2 sat 93,BP 100/35.There were no focal findings on exam.A 3-year-old boy has had a URI for 3-4 days.This morning his mother noted a swelling in his left neck.On exam he has a temper

30、ature of 102 and a tender,firm,slightly red mass in the left anterior cervical area.A 2-year-old boy has a fever and a 36 hour history of increasing leg pain and refusal to walk.On exam his temp is 102,he is holding his right leg in slight flexion and abduction,there is reduced range of motion of the hip,and he refuses to bear weight.A 12-month-old boy presents with clear nasal discharge for 2 days,difficulty sleeping,and tugging at his right ear.On exam he has a temperature of 102 degrees and a bulging,white,opaque,immobile right tympanic membrane.This is his first episode of otitis media.