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Streptococcus pneumoniae: does antimicrobial resistance matter?
Semin Respir Crit Care Med. 2009 Apr; 30(2):210-38.SR

Abstract

Over the past 3 decades, antimicrobial resistance among Streptococcus pneumoniae, the most common cause of community-acquired pneumonia (CAP), has escalated dramatically worldwide. In the late 1970s, strains of pneumococci displaying resistance to penicillin were described in South Africa and Spain. By the early 1990s, penicillin-resistant clones of S. pneumoniae spread rapidly across Europe and globally. Additionally, resistance to macrolides and other antibiotic classes escalated in tandem with penicillin resistance. Six international clones (serotypes 6A, 6B, 9V, 14, 19F, 23F) were responsible for most of these resistant isolates. Currently, 15 to 30% of S. pneumoniae worldwide are multidrug-resistant (MDR) (i.e., resistant to > or = 3 classes of antibiotics). Despite the dramatic escalation in the rate of antimicrobial resistance among pneumococci worldwide, the clinical impact of antimicrobial resistance is difficult to define. Treatment failures due to antibiotic-resistant pneumococci have been reported with meningitis, otitis media, and lower respiratory tract infections, but the relation between drug resistance and treatment failures has not been convincingly established. Clinical failures often reflect factors independent of antimicrobial susceptibility of the infecting organisms. Host factors (e.g., extremes of age; underlying immunosuppressive or debilitating disease; comorbidities), or factors that affect intrinsic virulence of the organisms (e.g., capsular subtype) strongly influence prognosis. Mortality rates are higher in the presence of: multilobar involvement, renal insufficiency, need for intensive care unit (ICU) care, hypoxemia, severe derangement in physiological parameters, and comorbidities. Given these confounding factors, dissecting out the impact of antimicrobial resistance on clinical outcomes is difficult, if not impossible. Prospective, randomized trials designed to assess the clinical significance of antimicrobial resistance among pneumococci are lacking, and for logistical reasons, will never be done. Does in vitro resistance translate into clinical failures? Should changing resistance patterns modify our choice of therapy for CAP or for suspected pneumococcal pneumonia? In this review, we discuss several facets, including mechanisms of antimicrobial resistance among specific antibiotic classes, epidemiology and spread of antimicrobial resistance determinants regionally and worldwide, risk factors for acquisition and dissemination of resistance, the impact of key international clones displaying multidrug resistance, the clinical impact of antimicrobial resistance, and strategies to limit or curtail antimicrobial resistance among this key respiratory tract pathogen.

Authors+Show Affiliations

Division of Pulmonary, Critical Care Medicine, Allergy, and Clinical Immunology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA. jplynch@mednet.ucla.eduNo affiliation info available

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

19296420

Citation

Lynch, Joseph P., and George G. Zhanel. "Streptococcus Pneumoniae: Does Antimicrobial Resistance Matter?" Seminars in Respiratory and Critical Care Medicine, vol. 30, no. 2, 2009, pp. 210-38.
Lynch JP, Zhanel GG. Streptococcus pneumoniae: does antimicrobial resistance matter? Semin Respir Crit Care Med. 2009;30(2):210-38.
Lynch, J. P., & Zhanel, G. G. (2009). Streptococcus pneumoniae: does antimicrobial resistance matter? Seminars in Respiratory and Critical Care Medicine, 30(2), 210-38. https://doi.org/10.1055/s-0029-1202939
Lynch JP, Zhanel GG. Streptococcus Pneumoniae: Does Antimicrobial Resistance Matter. Semin Respir Crit Care Med. 2009;30(2):210-38. PubMed PMID: 19296420.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Streptococcus pneumoniae: does antimicrobial resistance matter? AU - Lynch,Joseph P,3rd AU - Zhanel,George G, Y1 - 2009/03/18/ PY - 2009/3/20/entrez PY - 2009/3/20/pubmed PY - 2009/6/13/medline SP - 210 EP - 38 JF - Seminars in respiratory and critical care medicine JO - Semin Respir Crit Care Med VL - 30 IS - 2 N2 - Over the past 3 decades, antimicrobial resistance among Streptococcus pneumoniae, the most common cause of community-acquired pneumonia (CAP), has escalated dramatically worldwide. In the late 1970s, strains of pneumococci displaying resistance to penicillin were described in South Africa and Spain. By the early 1990s, penicillin-resistant clones of S. pneumoniae spread rapidly across Europe and globally. Additionally, resistance to macrolides and other antibiotic classes escalated in tandem with penicillin resistance. Six international clones (serotypes 6A, 6B, 9V, 14, 19F, 23F) were responsible for most of these resistant isolates. Currently, 15 to 30% of S. pneumoniae worldwide are multidrug-resistant (MDR) (i.e., resistant to > or = 3 classes of antibiotics). Despite the dramatic escalation in the rate of antimicrobial resistance among pneumococci worldwide, the clinical impact of antimicrobial resistance is difficult to define. Treatment failures due to antibiotic-resistant pneumococci have been reported with meningitis, otitis media, and lower respiratory tract infections, but the relation between drug resistance and treatment failures has not been convincingly established. Clinical failures often reflect factors independent of antimicrobial susceptibility of the infecting organisms. Host factors (e.g., extremes of age; underlying immunosuppressive or debilitating disease; comorbidities), or factors that affect intrinsic virulence of the organisms (e.g., capsular subtype) strongly influence prognosis. Mortality rates are higher in the presence of: multilobar involvement, renal insufficiency, need for intensive care unit (ICU) care, hypoxemia, severe derangement in physiological parameters, and comorbidities. Given these confounding factors, dissecting out the impact of antimicrobial resistance on clinical outcomes is difficult, if not impossible. Prospective, randomized trials designed to assess the clinical significance of antimicrobial resistance among pneumococci are lacking, and for logistical reasons, will never be done. Does in vitro resistance translate into clinical failures? Should changing resistance patterns modify our choice of therapy for CAP or for suspected pneumococcal pneumonia? In this review, we discuss several facets, including mechanisms of antimicrobial resistance among specific antibiotic classes, epidemiology and spread of antimicrobial resistance determinants regionally and worldwide, risk factors for acquisition and dissemination of resistance, the impact of key international clones displaying multidrug resistance, the clinical impact of antimicrobial resistance, and strategies to limit or curtail antimicrobial resistance among this key respiratory tract pathogen. SN - 1098-9048 UR - https://www.unboundmedicine.com/medline/citation/19296420/Streptococcus_pneumoniae:_does_antimicrobial_resistance_matter L2 - http://www.thieme-connect.com/DOI/DOI?10.1055/s-0029-1202939 DB - PRIME DP - Unbound Medicine ER -