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Deeks SL, Palacio R, Ruvinsky R, Kertesz DA, Hortal M, Rossi A, Spika JS, Di Fabio JL. Risk factors and course of illness among children with invasive penicillin-resistant Streptococcus pneumoniae. The Streptococcus pneumoniae Working Group. Pediatrics 1999; 103:409-13. [PMID: 9925833 DOI: 10.1542/peds.103.2.409] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES To assess differences in risk factors, clinical presentation, and course of illness between children infected with penicillin-sensitive and drug-resistant Streptococcus pneumoniae (DRSP). DESIGN A retrospective cohort study conducted in Uruguay and Argentina using information from a hospital-based surveillance system. Hospitalized children 5 years of age and younger who had S pneumoniae isolated from a normally sterile site between June 1993 and October 1996 were eligible. Hospital records were linked with surveillance data. Both stratified univariate analysis and logistic regression was completed. RESULTS Of the 380 children eligible for the study, 274 records (72%) were available for review. Ninety-nine children (36%) had DRSP; 46 showed intermediate susceptibility (minimum inhibitory concentration, 0.12-1.0 microg/mL) and 53 showed high-level resistance (minimum inhibitory concentration >/=2.0 microg/mL). Children with meningitis were less likely to have DRSP than those with other forms of invasive disease (relative risk = 0. 5; 95% confidence interval [CI], 0.2-0.9). Risk factors associated with DRSP were use of penicillin or ampicillin in the 3 months before illness (odds ratio = 2.9; 95% CI, 1.5-5.7) and possession of private medical coverage (odds ratio = 2.4; 95% CI, 1.2-5.0). Response to therapy, including response to penicillin or ampicillin among children with nonmeningeal invasive disease, course of illness, and clinical outcome did not differ significantly between children infected with penicillin-susceptible or penicillin-resistant isolates. CONCLUSION In this study, previous use of penicillin or ampicillin and private medical coverage were associated with having DRSP. Children with nonmeningeal invasive disease responded equally well to penicillin regardless of the penicillin susceptibility of their pneumococcal isolate.
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Affiliation(s)
- S L Deeks
- Bureau of Infectious Diseases, Laboratory Centre for Disease Control, Health Canada, Ottawa, Canada
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52
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Aldridge KE, Ashcraft DS, O'Cain P, Sanders CV, Janney A, Brown W, Silberman R, Pankey GK. A multicenter study of the prevalence and susceptibility patterns of isolates of Streptococcus pneumoniae with reduced susceptibility to penicillin G in Louisiana. Am J Med Sci 1998; 316:277-84. [PMID: 9766490 DOI: 10.1097/00000441-199810000-00009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Because of increasing reports of multiple-antibiotic-resistant strains of Streptococcus pneumoniae and associated clinical failures, this study was performed to determine the prevalence of multiresistance among strains from nine Louisiana medical centers. Using a National Committee for Laboratory Standards broth microdilution method, 481 strains were tested. Of these, 70% were penicillin-susceptible (PS), 23% had intermediate minimum inhibitory concentration values to penicillin (I), and 7% were fully resistant to penicillin (PR). The isolation rates (15% to 40% for I strains and 0% to 33% for PR strains) at the various medical centers varied appreciably. The prevalence of penicillin resistance was highest among upper respiratory isolates, while cross-resistance to other antimicrobials varied. The least cross-resistance was noted among PS strains. However, strains with reduced penicillin susceptibility had high levels of cross-resistance. Among I strains, the prevalence of cross-resistance (%) was noted for amoxicillin/clavulanate (6%), cefuroxime (71%), cefaclor (91%), ceftriaxone (13%), cefotaxime (34%), erythromycin (67%), azithromycin (32%), and clarithromycin (32%). For PR strains, the prevalence of cross-resistance was 97% for amoxicillin/clavulanate, cefuroxime, and cefaclor; 67% for ceftriaxone and erythromycin; 89% for cefotaxime; and 69% for azithromycin and clarithromycin. These data emphasize the high prevalence of multiple-antimicrobial-resistance among strains of S pneumoniae with reduced penicillin susceptibility in this geographic area.
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Affiliation(s)
- K E Aldridge
- Department of Medicine, Louisiana State University Medical Center, New Orleans 70112, USA
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53
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Kaplan SL, Mason EO. Management of infections due to antibiotic-resistant Streptococcus pneumoniae. Clin Microbiol Rev 1998; 11:628-44. [PMID: 9767060 PMCID: PMC88901 DOI: 10.1128/cmr.11.4.628] [Citation(s) in RCA: 172] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antibiotic-resistant strains of Streptococcus pneumoniae are becoming more prevalent throughout the world; this has resulted in modifications of treatment approaches. Management of bacterial meningitis has the greatest consensus. Strategies for treating other systemic infections such as pneumonia, bacteremia, and musculoskeletal infections are evolving, in part related to the availability of new antibiotics which are active in vitro against isolates resistant to penicillin and the extended-spectrum cephalosporins. However, there are currently very limited data related to the clinical efficacy of these new agents. The studies upon which current recommendations are based are reviewed. Otitis media represents the single most common infection due to S. pneumoniae. Recommendations for treatment of acute otitis media due to drug-resistant strains and the rationale for these recommendations are discussed.
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Affiliation(s)
- S L Kaplan
- Section of Pediatric Infectious Diseases, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA.
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54
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Spach DH, Black D. Antibiotic resistance in community-acquired respiratory tract infections: current issues. Ann Allergy Asthma Immunol 1998; 81:293-302; quiz 302-3. [PMID: 9809491 DOI: 10.1016/s1081-1206(10)63121-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE In recent years, antibiotic resistance has emerged as an important global problem. The major goal of this review is to update important issues pertaining to antibiotic resistance, with an emphasis on antibiotic resistance involving community-acquired respiratory pathogens. In addition, this review examines potential reasons why antibiotic resistance has increased in recent years, how clinicians can better understand commonly used laboratory antibiotic resistance tests, and possible solutions to the increasing problem of antibiotic resistance. The article emphasizes the diagnosis, therapy, and prevention of antibiotic-resistant infections. DATA SOURCES We identified relevant English-language articles through MEDLINE search (1966 to March 1998). All articles related to antibiotic resistance and the scope of the articles included original investigative articles, reviews, letters, and editorials. In addition, we selected additional references from the bibliographies of the identified articles. STUDY SELECTION We selected articles for detailed review if they provided direct insight into the cause of antibiotic resistance, testing for antibiotic resistance, or the treatment of antibiotic resistance. Most, but not all, of the articles selected pertained to antibiotic resistance and respiratory tract infections. We performed a detailed review on approximately 40% of the originally selected articles. RESULTS Multiple factors that play a significant role in the development of antibiotic resistance include the overuse of antibiotics in both humans and animals, situations such as day care that enhance transmission via frequent close personal contact, and widespread dissemination of resistant strains via global travel. Most respiratory pathogens have developed resistance to commonly used antibiotics either by producing beta-lactamase or by altering binding site proteins. CONCLUSIONS In many regions of the United States, the level of antibiotic resistance has impacted the clinical management of common respiratory pathogens. Future efforts to curtail antibiotic resistance will require a concerted effort in multiple areas, particularly enhanced epidemiologic surveillance to better detect resistance trends, judicious use of antibiotics, and new drug development.
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Affiliation(s)
- D H Spach
- Division of Infectious Diseases, University of Washington, Seattle, USA
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55
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Aldridge KE, Ashcraft DS, O'Cain P, Sanders CV, Janney A, Brown W, Silberman R, Pankey GK. A Multicenter Study of the Prevalence and Susceptibility Patterns of Isolates of Streptococcus pneumoniae with Reduced Susceptibility to Penicillin G in Louisiana. Am J Med Sci 1998. [DOI: 10.1016/s0002-9629(15)40419-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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56
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Kaplan SL, Mason EO, Barson WJ, Wald ER, Arditi M, Tan TQ, Schutze GE, Bradley JS, Givner LB, Kim KS, Yogev R. Three-year multicenter surveillance of systemic pneumococcal infections in children. Pediatrics 1998; 102:538-45. [PMID: 9738174 DOI: 10.1542/peds.102.3.538] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To track antibiotic susceptibility of Streptococcus pneumoniae isolates obtained from children with systemic infections and determine outcome of treatment. DESIGN A 3-year (September 1993 through August 1996) prospective surveillance study of all invasive pneumococcal infections in children. PATIENTS Infants and children cared for at eight children's hospitals in the United States with culture-proven systemic pneumococcal infection. RESULTS One thousand two hundred ninety-one episodes of systemic pneumococcal infection were identified in 1255 children. An underlying illness was present in the children for 27% of the episodes. The proportion of isolates that were nonsusceptible to penicillin or ceftriaxone increased annually and nearly doubled throughout the 3-year period; for the last year the percentages of isolates nonsusceptible to penicillin and ceftriaxone were 21% and 9.3%, respectively. There was no difference in mortality between patients with penicillin-susceptible or nonsusceptible isolates. Only 1 of 742 patients with bacteremia had a repeat blood culture that was positive > 1 day after therapy was started. All 24 normal children with bacteremia attributable to isolates resistant to penicillin had resolution of their infection; the most common treatment regimen was a single dose of ceftriaxone followed by an oral antibiotic. CONCLUSIONS The percentage of pneumococcal isolates nonsusceptible to penicillin and ceftriaxone increased yearly among strains recovered from children with systemic infection. Because empiric antibiotic therapy already has changed for suspected pneumococcal infections, antibiotic resistance has not been associated with increased mortality. Careful monitoring of antibiotic susceptibility and outcome of therapy is necessary to continually reassess current recommendations for treatment.
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Affiliation(s)
- S L Kaplan
- Pediatric Infectious Disease Section, Baylor College of Medicine, Houston, TX 77030, USA
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57
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Abstract
In patients with otitis media or sinusitis, antibiotics must be used judiciously. First-line treatment for both uncomplicated acute otitis media and acute sinusitis is amoxicillin. Erythromycin ethylsuccinate and sulfisoxazole or TMP-SMZ may be used in patients who are allergic to penicillin. Beta-lactamase-stable agents should be given when no response occurs within 48 to 72 hours. In cases in which penicillin-resistant pneumococcus is suspected, high-dose amoxicillin, with or without clavulanate, or clindamycin should be considered. Antibiotics are not indicated for initial treatment of otitis media with effusion but may be considered for effusions lasting longer than 3 months. Prophylactic antibiotics should be considered only for recurrent acute infections occurring three or more times within 6 months or four or more times within a year. The common cold should not be treated with antibiotics, and antimicrobial therapy should be initiated only when there is reasonable clinical certainty about the presence of acute sinusitis.
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Affiliation(s)
- G S Ahuja
- Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, College of Medicine, Orange 92868, USA.
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58
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Geslin P, Fremaux A, Sissia G, Spicq C, Georges S. [Development of resistance to beta-lactams and other antibiotics of pneumococci isolated from acute otitis media in France: statement of the National Reference Center 1995-1996]. Arch Pediatr 1998; 5:982-7. [PMID: 9789629 DOI: 10.1016/s0929-693x(98)80007-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
POPULATION AND METHODS During 1995 and 1996, 393 and 566 strains of Streptococcus pneumoniae, isolated from acute otitis media, were respectively sent to the National Reference Center for Pneumococci by its corresponding centers. RESULTS The resistance rates for 1995 and 1996 were respectively: for penicillin: 65.4 and 70.3% (18.6 and 24.9% of intermediately resistant strains, 46.8 and 45.4% of fully resistant strains), for erythromycin: 57.5 and 68.5%, for tetracycline: 43.2 and 42.6%, for trimethoprim-sulfamethoxazole: 47.5 and 50.9%. Minimal inhibitory concentrations (MICs) of various betalactams were determined against a representative sample of strains (n = 99). CONCLUSION Amoxicillin, cefpodoxime and cefuroxime MICs remained low against numerous penicillin resistant strains, indicating that these three oral antibiotics (in combination with clavulanate for amoxicillin) have a useful potential for the treatment of acute otitis media when risk factors for pneumococcal penicillin-resistant infections are detected.
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Affiliation(s)
- P Geslin
- Centre national de référence des pneumocoques, centre hospitalier intercommunal, Créteil, France
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Heikkinen T, Ghaffar F, Okorodudu AO, Chonmaitree T. Serum interleukin-6 in bacterial and nonbacterial acute otitis media. Pediatrics 1998; 102:296-9. [PMID: 9685429 DOI: 10.1542/peds.102.2.296] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Increasing prevalence of antibiotic-resistant bacteria is a serious clinical problem that calls for reduction of unnecessary use of antibiotics. Acute otitis media (AOM) is the most common reason for antibiotic therapy in the United States. Approximately 30% of AOM cases do not have a bacterial etiology. Rapid identification of these cases could help withhold unnecessary antibiotic treatment. OBJECTIVE To determine the usefulness of serum levels of interleukin-6 (IL-6), an acute phase cytokine shown to be a reliable marker of neonatal bacterial infection, in differentiation between bacterial and nonbacterial AOM in children. STUDY DESIGN IL-6 was measured in stored serum samples from 184 children (mean age, 22 months) with AOM who were enrolled in antibiotic efficacy trials at our department. The samples were obtained at enrollment and at 9 to 12 days after initiation of antibiotic therapy. Sera from 21 uninfected children (mean age, 23 months) were used as controls. The etiology of AOM was determined by bacterial and viral cultures as well as respiratory syncytial virus antigen detection in the middle ear fluids obtained by tympanocentesis. RESULTS Bacterial etiology of AOM was confirmed in 125 children (68%), whereas in 59 children (32%) no bacterial pathogen could be detected in the middle ear fluid. Children with bacterial AOM had significantly higher IL-6 levels than those with nonbacterial AOM (median, 11.5 vs 3.7 pg/mL). However, this difference was almost entirely attributable to pneumococcal AOM specifically. IL-6 levels in children with AOM caused by Streptococcus pneumoniae were significantly higher (median, 40.1 pg/mL) than in AOM caused by Haemophilus influenzae (7.3 pg/mL) or Moraxella catarrhalis (6.8 pg/mL). At the cutoff value of 30 pg/mL, the specificity of IL-6 for detection of pneumococcal AOM was 91% with a sensitivity of 61%, but its sensitivity for detection of bacterial AOM in general was only 27%. CONCLUSIONS Low levels of IL-6 do not rule out bacterial etiology of AOM in general; therefore, IL-6 is not sensitive enough as a marker of bacterial AOM. Surprisingly, serum IL-6 levels in pneumococcal AOM were significantly higher than the levels associated with other bacterial AOM, and serum IL-6 levels of >30 pg/mL were highly specific for pneumococcal AOM. These findings suggest a distinctive role for S pneumoniae in the pathogenesis of AOM.
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Affiliation(s)
- T Heikkinen
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas 77555-0371, USA
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60
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Leibovitz E, Raiz S, Piglansky L, Greenberg D, Yagupsky P, Fliss DM, Leiberman A, Dagan R. Resistance pattern of middle ear fluid isolates in acute otitis media recently treated with antibiotics. Pediatr Infect Dis J 1998; 17:463-9. [PMID: 9655535 DOI: 10.1097/00006454-199806000-00005] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Little information is available about the effect of antibiotic treatment on the prevalence and MIC of the subsequently isolated pathogens in cases of acute otitis media (AOM) failing a course of antibiotic therapy. This information is important, particularly regarding the effectiveness of the oral antibiotics used in children failing initial therapy. PATIENTS AND METHODS One hundred eighty-one children with culture-positive AOM were prospectively studied between October, 1995, and July, 1996. Sixty-three (35%) patients received various antibiotics for variable periods during the 14 days preceding enrollment. RESULTS A total of 94 Streptococcus pneumoniae (Pnc) and 113 Haemophilus influenzae (Hi) were isolated. Thirty-eight Pnc and 35 Hi were isolated in the 63 patients with recently treated AOM. Pnc as a single isolate was more prevalent in patients recently treated with antibiotics (27 of 63, 43%) than among those not recently treated (32 of 118, 27%, P = 0.047). The MIC50 values of penicillin, cefaclor and cefuroxime axetil for Pnc were significantly higher in the pneumococci isolated from patients recently treated than among those isolated from patients not recently treated with antibiotics (0.38, 3 and 0.75 microg/ml vs. 0.094, 0.38 and 0.12 microg/ml, respectively). Seventy-nine percent of Pnc isolates in the recently treated group had MIC for penicillin of >0.1 microg/ml vs. only 47% in those not recently treated (P < 0.05). The respective figures for MIC >0.5 microg/ml of cefaclor were 79% vs. 41% for the recently treated and not recently treated groups (P < 0.001); cefuroxime MIC >0.5 microg/ml was found in 61 and 25%, respectively (P = 0.001). CONCLUSIONS Pneumococcus is more prevalent in AOM after a recent antibiotic treatment, and the MIC of the commonly used beta-lactam drugs for Pnc is considerably higher in this setting. In view of our data, the use of oral cephalosporins like cefaclor or cefuroxime as second line drugs in the treatment of unresponsive AOM, particularly in regions where resistant PNC is prevalent, should be reconsidered.
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Affiliation(s)
- E Leibovitz
- Pediatric Infectious Disease Unit, Soroka University Medical Center and the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Affiliation(s)
- S A Chartrand
- Creighton University, Department of Pediatrics, Omaha, NE 68178, USA
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Canafax DM, Yuan Z, Chonmaitree T, Deka K, Russlie HQ, Giebink GS. Amoxicillin middle ear fluid penetration and pharmacokinetics in children with acute otitis media. Pediatr Infect Dis J 1998; 17:149-56. [PMID: 9493813 DOI: 10.1097/00006454-199802000-00014] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Acute otitis media (AOM) is a common childhood infectious disease. The efficacy of antibiotic dosing regimens is usually assessed by antibiotic plasma pharmacokinetics or middle ear fluid (MEF) concentration at one or two time points. Viral coinfection in AOM reduced antibacterial efficacy of antibiotics. OBJECTIVE To determine amoxicillin MEF penetration and pharmacokinetics in bacterial and combined bacterial and viral AOM. METHODS Thirty-four children with AOM were enrolled, and MEF was collected by tympanocentesis for bacterial culture and viral studies. Nasal wash and venous blood were also obtained for viral culture and serologic studies, respectively. Subjects were treated with amoxicillin 40 mg/kg/day orally, divided in equal doses every 8 h. During the second visit (48 to 72 h later) the subjects, with the regular morning amoxicillin dose withheld, were given an oral amoxicillin dose of 25 mg/kg. Thereafter two blood samples and one MEF sample by tympanocentesis were collected from each child at selected times between 0.5 and 4.0 h after dosing for bacterial and viral studies and amoxicillin concentration determination by high performance liquid chromatography. RESULTS Eleven (37%) children had only bacterial infection, 6 (20%) had viral infection only, 6 (20%) had both bacterial and viral infections and in 7 (23%) neither bacterial nor viral pathogens were recovered. MEF bacterial culture was positive in 23 of 40 ears (57.5%) before treatment with amoxicillin (40 mg/kg/day) and was still positive in 4 of 38 ears (10.5%) after 2 to 3 days of treatment. Amoxicillin plasma concentration reached its peak at 1.0 to 1.5 h after a 25-mg/kg oral dose. The estimated MEF concentration peak occurred 3.0 h after the dose with MEF concentrations ranging from undetectable to 20.6 microg/ml and a mean of approximately 9.5 microg/ml. Geometric mean amoxicillin concentrations were lowest in virus-infected children (2.7 microg/ml), nearly the same in culture-negative samples from children without viral infection (2.9 microg/ml), higher in children with combined bacterial and viral infection (4.1 microg/ml) and highest in children with bacterial-only infection (5.7 microg/ml). CONCLUSIONS MEF amoxicillin penetration tended to be lower in children with viral infection. The current amoxicillin dosing recommendation of 40 mg/kg/day in three divided dose is inadequate to effectively eradicate resistant Streptococcus pneumoniae, particularly during viral coinfection. A dosing regimen of 75 to 90 mg/kg/day is recommended for AOM.
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Affiliation(s)
- D M Canafax
- Otitis Media Research Center, Department of Pharmacy Practice, College of Pharmacy, University of Minnesota, Minneapolis, USA
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Heffernan R, Henning K, Labowitz A, Hjelte A, Layton M. Laboratory survey of drug-resistant Streptococcus pneumoniae in New York City, 1993-1995. Emerg Infect Dis 1998; 4:113-6. [PMID: 9452405 PMCID: PMC2627676 DOI: 10.3201/eid0401.980116] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Wide geographic variation in the prevalence of drug-resistant Streptococcus pneumoniae demonstrates the importance of tracking antimicrobial resistance locally. This survey of hospital microbiology laboratories in New York City found that penicillin resistance (MIC > or = 2.0 micrograms/ml) increased from 1.5% of S. pneumoniae isolates in 1993 to 6.3% in 1995 and that in 1995, one-third of isolates nonsusceptible to penicillin (MIC > or = 0.1 microgram/ml) were also nonsusceptible to an extended-spectrum cephalosporin (MIC > or = 1 microgram/ml).
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Affiliation(s)
- R Heffernan
- New York City Department of Health, New York, USA
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64
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LOWER RESPIRATORY TRACT INFECTIONS IN ELDERLY PATIENTS WITH ASTHMA. Immunol Allergy Clin North Am 1997. [PMCID: PMC7135044 DOI: 10.1016/s0889-8561(05)70337-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Infection plays a significant role in the morbidity and mortality of the elderly. One population in which infection has not been adequately studied is the elderly asthmatic. This article examines the problems of lower respiratory tract infections in elderly asthmatics in the context of their host defenses, the severity of infection, and their risk of infection with specific organisms. The role of infection in the pathogenesis of asthma and consideration of prophylaxis and therapy are presented.
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Abstract
Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are the most frequently isolated pathogens in patients with acute otitis media (AOM). Other potential causative pathogens include Streptococcus pyogenes in older children and Chlamydia pneumoniae in younger children. The recent emergence of penicillin-resistant S. pneumoniae and the increasing frequency of beta-lactamase-producing strains of M. catarrhalis and H. influenzae are creating concerns regarding the use of amoxicillin as traditional first line empiric therapy for AOM in younger children. Both the in vitro antibiotic activity against these more resistant causative pathogens and the antibiotic concentrations achieved in middle ear fluid must be considered when selecting antibiotics for treatment of refractory AOM. The newer macrolides, azithromycin and clarithromycin, provide reasonable in vitro coverage against penicillin-resistant S. pneumoniae and beta-lactamase-producing H. influenzae, although azithromycin is more active against the latter. Both drugs also achieve notably higher, sustained concentrations in middle ear fluid than do beta-lactam antibiotics. Thus the newer macrolides represent important new rational alternatives for the management of AOM.
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Affiliation(s)
- S L Block
- Kentucky Pediatric Research, Bardstown 40004, USA
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