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Antimicrobial Resistant Streptococcus pneumoniae: Prevalence, Mechanisms, and Clinical Implications. Am J Ther 2018; 24:e361-e369. [PMID: 28430673 DOI: 10.1097/mjt.0000000000000551] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Streptococcus pneumoniae is a major cause of pneumonia, meningitis, sepsis, bacteremia, and otitis media. S. pneumoniae has developed increased resistance to multiple classes of antibiotics. STUDY DESIGN Systematic literature review of prevalence, mechanisms, and clinical implications in S. pneumoniae resistance. AREAS OF UNCERTAINTY Since S. pneumoniae resistance to penicillin was first reported with subsequent development of resistance to other classes of drugs, selection of appropriate antibiotic treatment is challenging. DATA SOURCES We searched PubMed (English language) for citations to antibiotic resistance in S. pneumoniae published before March 1, 2016. RESULTS We present a review of S. pneumoniae resistance to beta-lactams, macrolides, lincosamides, fluoroquinolones, tetracyclines, and trimethoprim-sulfamethoxazole (TMP-SMX). There has been a steady decline in susceptibility of S. pneumoniae to commonly used beta-lactams. Phenotypic expression of penicillin resistance occurs as a result of a genetic structural modification in penicillin-binding proteins. Between 20% and 40% of S. pneumoniae isolates are resistant to macrolides. Macrolide resistance mechanisms include ribosomal target site alteration, alteration in antibiotic transport, and modification of the antibiotic. Approximately 22% of S. pneumoniae isolates are resistant to clindamycin. Similar to macrolide resistance, clindamycin involves a target site alteration. The prevalence of fluoroquinolone resistance is low, although increasing. S. pneumoniae resistance to fluoroquinolones occurs by accumulated mutations within the bacterial genome, increased efflux, or acquisition of plasmid-encoded genes. S. pneumoniae resistance has also increased for the tetracyclines. The primary mechanism is mediated by 2 genes that confer ribosomal protection. The prevalence of TMP-SMX resistance is around 35%. As with fluoroquinolones, resistance to TMP-SMX is secondary to mutations in the bacterial genome. CONCLUSIONS Effective treatment of resistant S. pneumoniae is a growing concern. New classes of drugs, newer formulations of older drugs, combination antibiotic therapy, nonantibiotic modalities, better oversight of antibiotic usage, and enhanced preventive measures hold promise.
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El Garch F, Lismond A, Piddock LJV, Courvalin P, Tulkens PM, Van Bambeke F. Fluoroquinolones induce the expression of patA and patB, which encode ABC efflux pumps in Streptococcus pneumoniae. J Antimicrob Chemother 2010; 65:2076-82. [DOI: 10.1093/jac/dkq287] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Lode HM, Schmidt-Ioanas M. Moxifloxacin: update and perspectives after 8 years of usage. Expert Rev Respir Med 2010; 2:443-53. [PMID: 20477208 DOI: 10.1586/17476348.2.4.443] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Moxifloxacin has a broad spectrum of activity, including Gram-positive and Gram-negative organisms, atypical respiratory pathogens, anaerobes and penicillin- and macrolide-resistant Streptococcus pneumoniae. It achieves good tissue penetration and high concentrations in clinically relevant tissues and fluids. It is available in both an oral and intravenous formulation, has a once-daily administration and a good tolerance and safety profile. Moxifloxacin is used mainly for the treatment of acute bacterial exacerbation of chronic bronchitis, community-acquired pneumonia, acute bacterial sinusitis, complicated skin and skin-structure infections and complicated intra-abdominal infections, as well as pulmonary TB, although it is not approved in this indication. The most recent studies covering these clinical indications are discussed.
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Affiliation(s)
- Hartmut M Lode
- RCMS Institute for Clinical Pharmacology, Charitè - Universitätsmedizin Berlin, Hohenzollerndamm 2, D10717 Berlin, Germany.
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Madurga S, Sánchez-Céspedes J, Belda I, Vila J, Giralt E. Mechanism of binding of fluoroquinolones to the quinolone resistance-determining region of DNA gyrase: towards an understanding of the molecular basis of quinolone resistance. Chembiochem 2009; 9:2081-6. [PMID: 18677735 DOI: 10.1002/cbic.200800041] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have studied the bacterial resistance to fluoroquinolones that arises as a result of mutations in the DNA gyrase target protein. Although it is known that DNA gyrase is a target of quinolone antibacterial agents, the molecular details of the quinolone-gyrase interaction remain unclear. The mode of binding of ciprofloxacin, levofloxacin, and moxifloxacin to DNA gyrase was analyzed by means of docking calculations over the surface of the QRDR of GyrA. The analysis of these binding models allows study of the resistance mechanism associated with gyrA mutations more commonly found in E. coli fluoroquinolone-resistant strains at the atomic level. Asp87 was found to be critical in the binding of these fluoroquinolones because it interacts with the positively charged nitrogens in these bactericidal drugs. The role of the other most common mutations at amino acid codon Ser83 can be explained through the contacts that the side chain of this residue establishes with fluoroquinolone molecules. Finally, our results strongly suggest that, although Arg121 has never been found to be associated with fluoroquinolone resistance, this residue makes a pivotal contribution to the binding of the antibiotic to GyrA and to defining its position in the QRDR of the enzyme.
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Affiliation(s)
- Sergio Madurga
- Institute for Research in Biomedicine, Baldiri Reixac 10, 08028 Barcelona, Spain
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Okumura R, Hirata T, Onodera Y, Hoshino K, Otani T, Yamamoto T. Dual-targeting properties of the 3-aminopyrrolidyl quinolones, DC-159a and sitafloxacin, against DNA gyrase and topoisomerase IV: contribution to reducing in vitro emergence of quinolone-resistant Streptococcus pneumoniae. J Antimicrob Chemother 2008; 62:98-104. [PMID: 18390884 DOI: 10.1093/jac/dkn136] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES DC-159a (a novel quinolone) and sitafloxacin (DU-6859a) are structurally related quinolones, bearing a 3-aminopyrrolidyl substitution. We investigated the relationship between the target preferences of these 3-aminopyrrolidyl quinolones, in vitro potencies and emergence of quinolone-resistant mutants in Streptococcus pneumoniae, compared with other quinolones. METHODS MICs, resistance frequencies and mutant prevention concentrations (MPCs) were determined using quinolone-susceptible strains and first-step parC mutant strains of S. pneumoniae. Target preferences were tested by the following two methods: antibacterial activities against gyrA or parC mutants and in vitro enzyme assays for the determination of 50% inhibition (IC(50)) values. RESULTS DC-159a and sitafloxacin exhibited potent antibacterial activities, low frequencies of mutant selection, low MPCs and narrow mutant selection windows against both quinolone-susceptible strains and first-step parC mutants of S. pneumoniae, compared with gatifloxacin, moxifloxacin and other quinolones tested. DC-159a and sitafloxacin showed relatively low MIC ratios against single gyrA or parC mutants relative to the wild-type strain and low IC(50) ratios against DNA gyrase and topoisomerase IV. CONCLUSIONS DC-159a and sitafloxacin demonstrated a more balanced dual-targeting activity than gatifloxacin, moxifloxacin and other quinolones tested. In addition, DC-159a and sitafloxacin have a lower propensity for selecting first- and second-step resistant mutants.
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Affiliation(s)
- Ryo Okumura
- Biological Research Laboratories IV, Daiichi Sankyo Co., Ltd, 1-16-13 Kitakasai, Edogawa-ku, Tokyo 134-8630, Japan.
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Shin JH, Jung HJ, Kim HR, Jeong J, Jeong SH, Kim S, Lee EY, Lee JN, Chang CL. Prevalence, characteristics, and molecular epidemiology of macrolide and fluoroquinolone resistance in clinical isolates of Streptococcus pneumoniae at five tertiary-care hospitals in Korea. Antimicrob Agents Chemother 2007; 51:2625-7. [PMID: 17502407 PMCID: PMC1913271 DOI: 10.1128/aac.00107-07] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genes erm(B), mef(A), and both erm(B) and mef(A) were identified in 42.6, 10.1, and 47.3%, respectively, of the erythromycin-resistant Streptococcus pneumoniae isolates. Of the strains, 3.8% were nonsusceptible to levofloxacin and had 1 to 6 amino acid changes in the quinolone resistance-determining region, including a new mutation, Asn94Ser, in the product of parC. Levofloxacin with reserpine was highly specific for efflux screening.
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Affiliation(s)
- Jeong Hwan Shin
- Department of Laboratory Medicine, College of Medicine, Inje University, 633-165 Gaegeum-Dong Busanjin-Gu, Busan, 614-110, Korea.
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Streptococcus pneumoniae. INFECTIOUS DISEASES IN CLINICAL PRACTICE 2007. [DOI: 10.1097/01.idc.0000239722.78078.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kays MB, Zhanel GG, Reimann MA, Jacobi J, Denys GA, Smith DW, Wack MF. Selection of agyrAMutation and Treatment Failure with Gatifloxacin in a Patient withStreptococcus pneumoniaewith a PreexistingparCMutation. Pharmacotherapy 2007; 27:221-6. [PMID: 17253913 DOI: 10.1592/phco.27.2.221] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An 81-year-old woman had pneumonia caused by Streptococcus pneumoniae (levofloxacin Etest minimum inhibitory concentration [MIC] 1.5 microg/ml) and was treated with intravenous gatifloxacin 200 mg/day. After 3 days of therapy, repeat sputum cultures were positive for S. pneumoniae, which was resistant to levofloxacin (Etest MIC > 32 microg/ml). The isolate obtained before therapy showed a preexisting parC mutation of aspartic acid-83 to asparagine (Asp83-->Asn), and the isolate obtained during therapy showed an acquired gyrA mutation from serine-81 to phenylalanine (Ser81-->Phe) and a second parC mutation from lysine-137 to Asn (Lys137-->Asn). Both isolates were the same strain, as determined with pulsed-field gel electrophoresis. This case demonstrates the potential for resistance to emerge during 8-methoxy fluoroquinolone therapy for fluoroquinolone-susceptible S. pneumoniae with a preexisting parC mutation. Additional clinical failures with a fluoroquinolone may occur unless these first-step parC mutants can be identified to assist clinicians in selecting appropriate antimicrobial therapy.
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Affiliation(s)
- Michael B Kays
- Department of Pharmacy Practice, Purdue University School of Pharmacy and Pharmaceutical Sciences, Indianapolis, Indiana 43202-2879, USA.
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Adam HJ, Schurek KN, Nichol KA, Hoban CJ, Baudry TJ, Laing NM, Hoban DJ, Zhanel GG. Molecular characterization of increasing fluoroquinolone resistance in Streptococcus pneumoniae isolates in Canada, 1997 to 2005. Antimicrob Agents Chemother 2006; 51:198-207. [PMID: 17088485 PMCID: PMC1797689 DOI: 10.1128/aac.00609-06] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Molecular characterization of fluoroquinolone-resistant Streptococcus pneumoniae in Canada was conducted from 1997 to 2005. Over the course of the study, 205 ciprofloxacin-resistant isolates were evaluated for ParC and GyrA quinolone resistance-determining region (QRDR) substitutions, substitutions in the full genes of ParC, ParE, and GyrA, reserpine sensitivity, and serotype and by pulsed-field gel electrophoresis. Rates of ciprofloxacin resistance of S. pneumoniae increased significantly, from less than 1% in 1997 to 4.2% in 2005. Ciprofloxacin resistance was greatest in people >64 years of age and least in those <16 years of age. Significant increases were also noted in rates of resistance to gatifloxacin, gemifloxacin, levofloxacin, and moxifloxacin, to the current rates of 1.6%, 1.0%, 1.1%, and 1.0%, respectively. The most common genotype observed consisted of QRDR substitutions in GyrA (Ser81Phe) and ParC (Ser79Phe). Substitutions outside the QRDR of GyrA, ParC, and ParE were not associated with fluoroquinolone resistance in this study. Overall, 21% of isolates were reserpine-sensitive and were thus assumed to be efflux positive. The ciprofloxacin-resistant isolates belonged to 35 different serotypes, but 10 (19F, 11A, 23F, 6B, 22F, 12F, 6A, 14, 9V, and 19A) accounted for 72% of all isolates. The majority of the isolates were found to be genetically unrelated by pulsed-field gel electrophoresis. Within the observed clusters, there was considerable genetic heterogeneity with regard to fluoroquinolone resistance mechanisms and serotypes. Continued surveillance and molecular analysis of fluoroquinolone-resistant S. pneumoniae in Canada are essential for appropriate empirical treatment of infections and early detection of novel resistance mechanisms.
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Affiliation(s)
- Heather J Adam
- Clinical Microbiology, Health Sciences Centre, MS673-820 Sherbrook St., Winnipeg, Manitoba R3A 1R9, Canada.
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10
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Sethi S. Moxifloxacin for the treatment of acute exacerbations of chronic obstructive pulmonary disease. Clin Infect Dis 2006; 41 Suppl 2:S177-85. [PMID: 15942884 DOI: 10.1086/428058] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND/PURPOSE The significant impact of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is now recognized. This recognition has led to increased efforts to provide evidence-based, appropriate treatment of AECOPD, to minimize its negative impact. This article reviews the bacterial etiology of AECOPD and clinical trials (both placebo-controlled and antibiotic comparison trials) that support the use of antibiotics for AECOPD, with an emphasis on the role of newer fluoroquinolones for the treatment of patients with this condition. A discussion of patient stratification that permits identification of those who require initial aggressive antibiotic therapy is presented. MAIN FINDINGS Among the treatment modalities for exacerbations, the role and choice of antibiotics is hotly debated. Current evidence supports the use of antibiotics in the treatment of AECOPD, because bacterial pathogens cause approximately half the exacerbations, and because empirical antibiotics have a significant benefit in most exacerbations. Several recent investigations have aided in the development of a rational antibiotic strategy for AECOPD. These include outcome studies that have identified patients who are likely to have a poor outcome of their exacerbation and, therefore, are candidates for aggressive initial antibiotic therapy. Studies of the new fluoroquinolone agents have shown superior short- and long-term clinical results among patients with AECOPD who are at risk of a poor outcome. CONCLUSIONS Theoretical concerns about the emergence of resistance to the fluoroquinolones dictate not only the appropriate use of these drugs but, also, the use of the most-potent agents available in this class, to sustain their usefulness over time. Such selected use of the new fluoroquinolones balances individual benefit with societal concerns regarding the use of these agents for the treatment of AECOPD.
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Affiliation(s)
- Sanjay Sethi
- Division of Pulmonary, Critical Care and Sleep Medicine, State University of New York, and Department of Veterans Affairs, Western New York Healthcare System, Buffalo, New York, USA.
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Schurek KN, Adam HJ, Hoban DJ, Zhanel GG. Call for the international adoption of microbiological breakpoints for fluoroquinolones and Streptococcus pneumoniae. Int J Antimicrob Agents 2006; 28:266-9. [PMID: 16904294 DOI: 10.1016/j.ijantimicag.2006.04.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Accepted: 04/13/2006] [Indexed: 11/19/2022]
Abstract
The use of current Clinical and Laboratory Standards Institute levofloxacin breakpoints for assessing fluoroquinolone resistance in Streptococcus pneumoniae is inadequate for detecting isolates possessing first-step parC mutations. Consequently, the risk for development of fluoroquinolone resistance is greatly underestimated. Adopting microbiological breakpoints for fluoroquinolones and S. pneumoniae, where parC mutations are rare in susceptible isolates, more accurately describes the emergence of resistance and may help to prevent a number of future fluoroquinolone treatment failures. Additionally, we propose that the use of a second fluoroquinolone marker, such as ciprofloxacin, offers the best prediction for detecting an isolate possessing a first-step parC mutation.
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Affiliation(s)
- Kristen N Schurek
- Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, 5th Floor Basic Medical Sciences Building, 730 William Avenue, Winnipeg, Manitoba, Canada R3E 0W3.
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Stanhope MJ, Walsh SL, Becker JA, Italia MJ, Ingraham KA, Gwynn MN, Mathie T, Poupard JA, Miller LA, Brown JR, Amrine-Madsen H. Molecular evolution perspectives on intraspecific lateral DNA transfer of topoisomerase and gyrase loci in Streptococcus pneumoniae, with implications for fluoroquinolone resistance development and spread. Antimicrob Agents Chemother 2006; 49:4315-26. [PMID: 16189113 PMCID: PMC1251522 DOI: 10.1128/aac.49.10.4315-4326.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fluoroquinolones are an important class of antibiotics for the treatment of infections arising from the gram-positive respiratory pathogen Streptococcus pneumoniae. Although there is evidence supporting interspecific lateral DNA transfer of fluoroquinolone target loci, no studies have specifically been designed to assess the role of intraspecific lateral transfer of these genes in the spread of fluoroquinolone resistance. This study involves a comparative evolutionary perspective, in which the evolutionary history of a diverse set of S. pneumoniae clinical isolates is reconstructed from an expanded multilocus sequence typing data set, with putative recombinants excluded. This control history is then assessed against networks of each of the four fluoroquinolone target loci from the same isolates. The results indicate that although the majority of fluoroquinolone target loci from this set of 60 isolates are consistent with a clonal dissemination hypothesis, 3 to 10% of the sequences are consistent with an intraspecific lateral transfer hypothesis. Also evident were examples of interspecific transfer, with two isolates possessing a parE-parC gene region arising from viridans group streptococci. The Spain 23F-1 clone is the most dominant fluoroquinolone-nonsusceptible clone in this set of isolates, and the analysis suggests that its members act as frequent donors of fluoroquinolone-nonsusceptible loci. Although the majority of fluoroquinolone target gene sequences in this set of isolates can be explained on the basis of clonal dissemination, a significant number are more parsimoniously explained by intraspecific lateral DNA transfer, and in situations of high S. pneumoniae population density, such events could be an important means of resistance spread.
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Schurek KN, Adam HJ, Siemens CG, Hoban CJ, Hoban DJ, Zhanel GG. Are fluoroquinolone-susceptible isolates of Streptococcus pneumoniae really susceptible? A comparison of resistance mechanisms in Canadian isolates from 1997 and 2003. J Antimicrob Chemother 2005; 56:769-72. [PMID: 16126779 DOI: 10.1093/jac/dki315] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To assess the prevalence of efflux and amino acid substitutions in ParC and GyrA in Canadian clinical isolates of fluoroquinolone-susceptible Streptococcus pneumoniae with levofloxacin MICs of 1 mg/L collected before the introduction of the respiratory fluoroquinolones (1995-1997) and after 7 years of use (2003). METHODS Quinolone resistance determining regions of parC and gyrA were sequenced for 111 clinical isolates collected from 1995 to 1997 and 665 isolates collected in 2003. Efflux was assessed using a reserpine agar dilution method. RESULTS No isolates exhibited efflux. No significant increase in isolates harbouring amino acid substitutions was observed over time (0.9% in 1995-1997 to 2.1% in 2003, P = 0.32). However, the proportion of isolates with a ciprofloxacin MIC = 2 mg/L and a levofloxacin MIC = 1 mg/L versus ciprofloxacin MIC = 1 mg/L and a levofloxacin MIC = 1 mg/L increased over time (3.6% to 6.5%, P = 0.0021). CONCLUSIONS No increase in prevalence of first-step parC mutations was observed among all fluoroquinolone-susceptible clinical isolates of S. pneumoniae with levofloxacin MICs of 1 mg/L after the introduction of the respiratory fluoroquinolones; however, fluoroquinolones appear to be selecting for isolates with elevated ciprofloxacin MICs.
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Affiliation(s)
- Kristen N Schurek
- Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, 5th Floor, Basic Medical Sciences Building, 730 William Avenue, Winnipeg, Manitoba, R3E 0W3, Canada.
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Abstract
Quinolones are one of the largest classes of antimicrobial agents used worldwide. This review considers the quinolones that are available currently and used widely in Europe (norfoxacin, ciprofloxacin, ofloxacin, levofloxacin and moxifloxacin) within their historical perspective, while trying to position them in the context of recent and possible future advances based on an understanding of: (1) their chemical structures and how these impact on activity and toxicity; (2) resistance mechanisms (mutations in target genes, efflux pumps); (3) their pharmacodynamic properties (AUC/MIC and Cmax/MIC ratios; mutant prevention concentration and mutant selection window); and (4) epidemiological considerations (risk of emergence of resistance, clonal spread). Their main indications are examined in relation to their advantages and drawbacks. Overall, it is concluded that these important agents should be used in an educated fashion, based on a careful balance between their ease of use and efficacy vs. the risk of emerging resistance and toxicity. However, there is now substantial evidence to support use of the most potent drug at the appropriate dose whenever this is required.
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Affiliation(s)
- F Van Bambeke
- Unit of Cellular and Molecular Pharmacology, Catholic University of Louvain, Brussels.
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15
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Abstract
Newer fluoroquinolones such as levofloxacin, moxifloxacin, gatifloxacin and gemifloxacin have several attributes that make them excellent choices for the therapy of lower respiratory tract infections. In particular, they have excellent intrinsic activity against Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and the atypical respiratory pathogens. Fluoroquinolones may be used as monotherapy to treat high-risk patients with acute exacerbation of chronic bronchitis, and for patients with community-acquired pneumonia requiring hospitalisation, but not admission to intensive care. Overall, the newer fluoroquinolones often achieve clinical cure rates in > or =90% of these patients. However, rates may be lower in hospital-acquired pneumonia, and this infection should be treated on the basis of anticipated organisms and evaluation of risk factors for specific pathogens such as Pseudomonas aeruginosa. In this setting, an antipseudomonal fluoroquinolone may be used in combination with an antipseudomonalbeta-lactam. Concerns are now being raised about the widespread use, and possibly misuse, of fluoroquinolones and the emergence of resistance among S. pneumoniae, Enterobacteriaceae and P. aeruginosa. A number of pharmacokinetic parameters such as the peak concentration of the antibacterial after a dose (C(max)), and the 24-hour area under the concentration-time curve (AUC24) and their relationship to pharmacodynamic parameters such as the minimum inhibitory and the mutant prevention concentrations (MIC and MPC, respectively) have been proposed to predict the effect of fluoroquinolones on bacterial killing and the emergence of resistance. Higher C(max)/MIC or AUC24/MIC and C(max)/MPC or AUC24/MPC ratios, either as a result of dose administration or the susceptibility of the organism, may lead to a better clinical outcome and decrease the emergence of resistance, respectively. Pharmacokinetic profiles that are optimised to target low-level resistant minor subpopulations of bacteria that often exist in infections may help preserve fluoroquinolones as a class. To this end, optimising the AUC24/MPC or C(max)/MPC ratios is important, particularly against S. pneumoniae, in the setting of lower respiratory tract infections. Agents such as moxifloxacin and gemifloxacin with high ratios against this organism are preferred, and agents such as ciprofloxacin with low ratios should be avoided. For agents such as levofloxacin and gatifloxacin, with intermediate ratios against S. pneumoniae, it may be worthwhile considering alternative dose administration strategies, such as using higher dosages, to eradicate low-level resistant variants. This must, of course, be balanced against the potential of toxicity. Innovative approaches to the use of fluoroquinolones are worth testing in further in vitro experiments as well as in clinical trials.
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Affiliation(s)
- Wael E. Shams
- Division of Infectious Diseases, Department of Internal Medicine, University of Kentucky School of Medicine, Room MN 672, 800 Rose Street, Lexington, Kentucky 40536 USA
- Department of Internal Medicine, University of Alexandria Faculty of Medicine, Alexandria, Egypt
- Division of Infectious Diseases, Department of Internal Medicine, East Tennessee State University, Johnson City, Tennessee USA
| | - Martin E. Evans
- Division of Infectious Diseases, Department of Internal Medicine, University of Kentucky School of Medicine, Room MN 672, 800 Rose Street, Lexington, Kentucky 40536 USA
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DeRyke CA, Maglio D, Nicolau DP. Defining the need for new antimicrobials: clinical and economic implications of resistance in the hospitalised patient. Expert Opin Pharmacother 2005; 6:873-89. [PMID: 15952918 DOI: 10.1517/14656566.6.6.873] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Resistance among pathogens causing the most common infections encountered in hospitalised patients is increasing. Due to this resistance, the clinical efficacy of current antimicrobial agents is decreasing against many pathogens, including Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Pseudomonas aeruginosa, extended-spectrum beta-lactamases, and AmpC beta-lactamase-producing organisms. Studies assessing the impact of these resistance mechanisms on clinical outcomes have been performed; however, studies determining the economic impact of resistance have been limited. Strategies to retain the clinical efficacy of currently available agents include the initiation of antimicrobials with efficacy against the suspected pathogen(s) based on data obtained from local antibiograms, the use of combination therapy, and pharmacodynamic optimisation. Once a broad-spectrum regimen has been initiated, de-escalation to narrow, targeted antimicrobial therapy based on susceptibility data is warranted. Despite these efforts, new antimicrobials with novel mechanisms of action are eagerly anticipated to extend the current armamentarium against the growing population of multi-drug-resistant pathogens.
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Affiliation(s)
- C Andrew DeRyke
- Center for Anti-infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102, USA
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Keam SJ, Croom KF, Keating GM. Gatifloxacin: a review of its use in the treatment of bacterial infections in the US. Drugs 2005; 65:695-724. [PMID: 15748100 DOI: 10.2165/00003495-200565050-00007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Gatifloxacin (Tequin) is an 8-methoxy fluoroquinolone approved in the US for use in the treatment of community-acquired pneumonia (CAP), acute exacerbations of chronic bronchitis (AECB), acute sinusitis, uncomplicated and complicated urinary tract infections (UTIs), pyelonephritis, gonorrhoea and uncomplicated skin and skin structure infections. Gatifloxacin has a broad spectrum of antibacterial activity in vitro and good clinical and bacteriological efficacy in patients with indicated infections following once-daily administration by the intravenous or oral routes. It is generally well tolerated; the most common adverse events are associated with the gastrointestinal tract and CNS. Recent approvals for the use of gatifloxacin in the treatment of CAP due to multidrug-resistant Streptococcus pneumoniae (MDRSP) and in uncomplicated skin and skin structure infections extend the role of this drug in the treatment of bacterial infections in the US.
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Affiliation(s)
- Susan J Keam
- Adis International Limited, Auckland, New Zealand.
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Abstract
Bacterial resistance to quinolones/fluoroquinolones has emerged rapidly and such resistance has traditionally been attributed to the chromosomally mediated mechanisms that alter the quinolone targets (i.e. DNA gyrase and topoisomerase IV) and/or overproduce multidrug resistance efflux pumps. However, the discovery of the plasmid-borne quinolone resistance determinant, named qnr, has substantially broadened our horizon on the molecular mechanisms of quinolone resistance. Several recent reports of Qnr or its homologues encoded by transferable plasmids in Gram-negative bacteria isolated worldwide highlight the significance of the emerging plasmid-mediated mechanism(s). This also alerts us to the potential rapid dissemination of quinolone resistance determinants. Qnr belongs to the pentapeptide repeat family and protects DNA gyrase from the action of quinolone agents including the newer fluoroquinolones. This protection interplays with chromosomal mechanisms to raise significantly the resistance levels. The qnr-bearing strains generate quinolone-resistant mutants at a much higher frequency than those qnr-free strains. Furthermore, the qnr-plasmids are integron-associated and carry multiple resistance determinants providing resistance to several classes of antimicrobials including beta-lactams and aminoglycosides. The high quinolone resistance rates in Escherichia coli are used to address issues of quinolone resistance, and possible strategies for minimising quinolone resistance are discussed.
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Affiliation(s)
- Xian-Zhi Li
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA.
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Mitscher LA. Bacterial topoisomerase inhibitors: quinolone and pyridone antibacterial agents. Chem Rev 2005; 105:559-92. [PMID: 15700957 DOI: 10.1021/cr030101q] [Citation(s) in RCA: 591] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lester A Mitscher
- Department of Medicinal Chemistry and Molecular Biosciences and The Chemical Methodologies and Library Development Center of Excellence, The University of Kansas, Lawrence, Kansas 66045-7582, USA.
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Zhanel GG, Hoban DJ, Schurek K, Karlowsky JA. Role of efflux mechanisms on fluoroquinolone resistance in Streptococcus pneumoniae and Pseudomonas aeruginosa. Int J Antimicrob Agents 2005; 24:529-35. [PMID: 15555873 DOI: 10.1016/j.ijantimicag.2004.08.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Prokaryotic efflux mechanisms can effectively increase the intrinsic resistance of bacteria by actively transporting antibiotics out of cells, thus reducing the effective concentration of these agents. The fluoroquinolones, similar to most other antimicrobial classes, are susceptible to efflux mechanisms, particularly in Gram-negative organisms, such as Pseudomonas aeruginosa. Resistant P. aeruginosa clones isolated after fluoroquinolone therapy frequently over express at least one of the multiple efflux pump mechanisms found in this organism. Gram-positive bacteria, such as Streptococcus pneumoniae, also possess efflux mechanisms, though their effect on fluoroquinolone resistance seems to be more limited and selective. In the future, efflux pump inhibitors may offer effective adjunctive therapy to antibiotics for the treatment of difficult infections by efflux mutants. In the meantime, appropriate antibiotic selection and optimal dosing strategies should aim to eradicate the causative pathogen before a resistant efflux mutant can emerge.
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Affiliation(s)
- George G Zhanel
- Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Manitoba, Canada.
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Smith-Adam HJ, Nichol KA, Hoban DJ, Zhanel GG. Stability of fluoroquinolone resistance in Streptococcus pneumoniae clinical isolates and laboratory-derived mutants. Antimicrob Agents Chemother 2005; 49:846-8. [PMID: 15673786 PMCID: PMC547370 DOI: 10.1128/aac.49.2.846-848.2005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The stability of fluoroquinolone resistance in Streptococcus pneumoniae was evaluated in laboratory-derived mutants and clinical isolates. Isolates with various genotypes and phenotypes were subcultured for 20 days on antibiotic-free media and were monitored by E-tests to identify any alterations in resistance. Fluoroquinolone resistance mechanisms, whether efflux or chromosomally mediated, remained stable in both clinical and laboratory-derived mutants.
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Affiliation(s)
- Heather J Smith-Adam
- Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, R3A 1R9 Canada.
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Abstract
Gatifloxacin (Tequin, Kyorin Pharmaceutical Co. Ltd) is a new fluoroquinolone with a broad spectrum of activity for pathogens implicated in community-acquired respiratory tract infections, including Gram-positive, -negative and atypical bacteria. Excellent oral bioavailability, a half-life allowing once-daily administration and excellent penetration into respiratory tissues are desirable pharmacokinetic characteristics of gatifloxacin. Monte Carlo simulation of gatifloxacin in Streptococcus pneumoniae infection demonstrates that adequate levels of pharmacokinetic/pharmacodynamic parameters are obtained with gatifloxacin in almost all instances. In randomised, controlled trials and a large open-label, community-based study, gatifloxacin has shown excellent clinical and bacteriological efficacy in acute bacterial sinusitis, acute exacerbations of chronic bronchitis and community-acquired pneumonia. Current guidelines recommend the initial empiric use of gatifloxacin (along with the other new fluoroquinolones) for community-acquired respiratory tract infection in patients who have increased likelihood of infection with resistant pathogens. Another group of patients where this agent is recommended for initial antimicrobial therapy are those who, because of underlying disease and/or comorbid conditions, need an antibiotic with high antimicrobial efficacy to achieve optimal outcomes.
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Affiliation(s)
- Sanjay Sethi
- Department of Medicine, Division of Pulmonary/Critical Care/Sleep Medicine, University at Buffalo SUNY, Buffalo, NY 14215, USA.
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Abstract
Moxifloxacin (Avelox) is a fluoroquinolone antibacterial with a methoxy group in the C-8 position and a bulky C-7 side chain. Moxifloxacin is approved for use in the treatment of acute exacerbations of chronic bronchitis (AECB), community-acquired pneumonia (CAP), acute bacterial sinusitis and uncomplicated skin and skin structure infections (approved indications may differ between countries). Moxifloxacin has a broad spectrum of antibacterial activity, including activity against penicillin-resistant Streptococcus pneumoniae. It achieves good tissue penetration and has a convenient once-daily administration schedule, as well as being available in both intravenous and oral formulations in some markets. Moxifloxacin has good efficacy in the treatment of patients with AECB, CAP, acute bacterial sinusitis and uncomplicated skin and skin structure infections, and is generally well tolerated. Thus, moxifloxacin is an important option in the treatment of bacterial infections.
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Richter SS, Heilmann KP, Beekmann SE, Miller NJ, Rice CL, Doern GV. The Molecular Epidemiology of Streptococcus pneumoniae with Quinolone Resistance Mutations. Clin Infect Dis 2005; 40:225-35. [PMID: 15655739 DOI: 10.1086/426817] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Accepted: 09/01/2004] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND The purpose of this study was to determine the prevalence of fluoroquinolone resistance and quinolone resistance-determining region (QRDR) mutations among Streptococcus pneumoniae isolates in the United States during the period of 2001-2002. A second objective was to examine the genetic relatedness of pneumococcal isolates with parC and/or gyrA mutations during the period of 1994-2002. METHODS Susceptibility testing was performed for 1902 S. pneumoniae isolates collected in the United States during the period of 2001-2002. On the basis of the minimum inhibitory concentration (MIC) of ciprofloxacin, 146 isolates were selected from the 2001-2002 study for QRDR analysis of parC, parE, gyrA, and gyrB genes. The genetic relatedness of isolates with parC and/or gyrA mutations from 2001-2002 (n=55) and from 3 US surveillance studies conducted during 1994-2000 (n=56) was determined by pulsed-field gel electrophoresis (PFGE). RESULTS Between 1999-2000 and 2001-2002, there was a 2-fold increase in the rate of ciprofloxacin resistance (MIC, >or=4 micro g/mL), from 1.2% to 2.7%, and in the rate of levofloxacin nonsusceptibility (MIC, >or=4 micro g/mL), from 0.6% to 1.3%. The 111 isolates with parC and/or gyrA mutations were assigned to 48 different PFGE types. Forty-four isolates (40%) belonged to 8 PFGE types that were closely related to widespread clones. Fifteen of the 43 levofloxacin-nonsusceptible pneumococci (LNSP) belonged to 4 PFGE types that were closely related to major clones (Spain(23F)-1 [n=6]; Spain(6B)-2 [n=5], Taiwan(19F)-14 [n=2], and Tennessee(23F)-4 [n=2]). CONCLUSION The population of fluoroquinolone-resistant S. pneumoniae in the United States has increased but remains genetically diverse. However, 35% of LNSP were related to widespread pneumococcal clones, increasing the potential for the rapid spread of quinolone resistance in this species.
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Affiliation(s)
- S S Richter
- Department of Pathology, University of Iowa Carver College of Medicine, Iowa City 52242-1009, USA.
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Smith HJ, Noreddin AM, Siemens CG, Schurek KN, Greisman J, Hoban CJ, Hoban DJ, Zhanel GG. Designing fluoroquinolone breakpoints for Streptococcus pneumoniae by using genetics instead of pharmacokinetics-pharmacodynamics. Antimicrob Agents Chemother 2004; 48:3630-5. [PMID: 15328145 PMCID: PMC514724 DOI: 10.1128/aac.48.9.3630-3635.2004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We determined fluoroquinolone microbiological resistance breakpoints for Streptococcus pneumoniae by using genetic instead of pharmacokinetic-pharmacodynamic parameters. The proposed microbiological breakpoints define resistance as the MIC at which >50% of the isolates carry quinolone resistance-determining region mutations and/or, if data are available, when Monte Carlo simulations demonstrate a <90% chance of bacteriological eradication. The proposed microbiological resistant breakpoints are as follows (in micrograms per milliliter): gatifloxacin, >0.25; gemifloxacin, >0.03; levofloxacin, >1; and moxifloxacin, >0.12. Monte Carlo simulations of the once daily 400-mg doses of gatifloxacin and 750-mg doses levofloxacin demonstrated a high level of target attainment (free-drug area under the concentration-time curve from 0 to 24 h/MIC ratio of 30) by using these new genetically derived breakpoints.
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Affiliation(s)
- H J Smith
- Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Canada.
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Pletz MWR, McGee L, Jorgensen J, Beall B, Facklam RR, Whitney CG, Klugman KP. Levofloxacin-resistant invasive Streptococcus pneumoniae in the United States: evidence for clonal spread and the impact of conjugate pneumococcal vaccine. Antimicrob Agents Chemother 2004; 48:3491-7. [PMID: 15328116 PMCID: PMC514755 DOI: 10.1128/aac.48.9.3491-3497.2004] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The emergence of fluoroquinolone resistance in sterile-site isolates of Streptococcus pneumoniae is documented in this study characterizing all invasive levofloxacin-resistant (MIC, > or = 8 mg/liter) S. pneumoniae isolates (n = 50) obtained from the Centers for Disease Control and Prevention Active Bacterial Core Surveillance from 1998 to 2002. Resistance among all isolates increased from 0.1% in 1998 to 0.6% in 2001 (P = 0.008) but decreased to 0.4% in 2002, while resistance among vaccine serotypes continued to increase from 0.3% in 1998 to 1.0% in 2002, suggesting that fluoroquinolones continue to exert selective pressure on these vaccine serotypes. Only 22% of resistant isolates were not covered by the conjugate vaccine serogroups. Multilocus sequence typing revealed that 58% of resistant strains were related to five international clones identified by the Pneumococcal Molecular Epidemiology Network, with the Spain(23F)-1 clone being most frequent (16% of all isolates). Thirty-six percent of the isolates were coresistant to penicillin, 44% were coresistant to macrolides, and 28% were multiresistant to penicillin, macrolides, and fluoroquinolones. Fifty percent of the isolates were resistant to any three drug classes. Ninety-four percent of the isolates had multiple mutations in the quinolone resistance-determining regions of the gyrA, gyrB, parC, and parE genes. In 16% of the isolates, there was evidence of an active efflux mechanism. An unusual isolate was found that showed only a single parE mutation and for which the ciprofloxacin MIC was lower (2 mg/liter) than that of levofloxacin (8 mg/liter). Our results suggest that invasive pneumococcal isolates resistant to levofloxacin in the United States show considerable evidence of multiple resistance and of clonal spread.
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Affiliation(s)
- Mathias W R Pletz
- Department of International Health, Rollins School of Public Health, Emory University, 1518 Clifton Rd., Atlanta, GA 30322, USA.
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Croisier D, Etienne M, Piroth L, Bergoin E, Lequeu C, Portier H, Chavanet P. In vivo pharmacodynamic efficacy of gatifloxacin against Streptococcus pneumoniae in an experimental model of pneumonia: impact of the low levels of fluoroquinolone resistance on the enrichment of resistant mutants. J Antimicrob Chemother 2004; 54:640-7. [PMID: 15317743 DOI: 10.1093/jac/dkh393] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To investigate the impact of low levels of fluoroquinolone resistance on the emergence of resistant mutants, we examined the mutant selection window (MSW) hypothesis in experimental pneumonia in rabbits infected with pneumococci with various susceptibility levels to fluoroquinolones and treated with gatifloxacin using a human-like regimen (equivalent to 400 mg once daily). The MSW corresponds to the range of concentrations between the minimal inhibitory concentration (MIC) and the mutant prevention concentration (MPC), which is the antibiotic concentration that prevents selection of resistant mutants. MATERIALS AND METHODS Five pneumococcal strains were tested and were defined as follows [MIC of ciprofloxacin (mg/L)/MIC of gatifloxacin (mg/L)/MPC of gatifloxacin (mg/L)/involved quinolone resistance mechanisms]: strain 16089=0.5/0.25/0.25/wild-type; strain MS1A=2/0.5/1/efflux; strain MS2A=8/1/8/parC S79F; strain MR3B4=10/1/8/parC S79T; strain Gyr-1207=6/4/4/gyrA S81F. RESULTS A 48 h human-like treatment with gatifloxacin was significantly bactericidal on pneumonia induced by strain 16089 ( > 6 log(10) killing) as well as the efflux derivative strain MS1A ( > 5 log(10) killing). However, a small number of parC-gyrA mutants were recovered in 26% of the animals infected with this efflux strain. As expected, no decrease in viable bacteria counts was observed when pneumonia was induced by the gyrA resistant strain. In contrast, because of the enrichment of highly resistant mutants in 100% of the animals, no significant bacterial reduction was observed after treatment of pneumonia induced by the two susceptible parC mutated strains. A classification and regression tree (CART) analysis identified T(MSW) (percentage of the time during which gatifloxacin serum concentrations are inside the MSW) and AUC(MSW) (area under curve between MIC and MPC values) as the best parameters associated with the enrichment of resistant pneumococci. CONCLUSIONS This study shows that the acquisition of a low level of fluoroquinolone resistance (especially a parC mutation and to a lesser extent an efflux mechanism) is associated with a clearly lower potential for preventing resistance development. These data support the concept that resistant mutants are selectively enriched when antibiotic concentrations fall inside the mutant selection window and suggest that in vivo dynamic models have to be used to predict the relative abilities of quinolones to prevent mutant selection.
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Affiliation(s)
- Delphine Croisier
- Service des Maladies Infectieuses, Microbiologie Médicale et Moléculaire, Hôpital du Bocage, 21000 Dijon Cedex, France
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Montanari MP, Tili E, Cochetti I, Mingoia M, Manzin A, Varaldo PE. Molecular Characterization of Clinical Streptococcus pneumoniae Isolates with Reduced Susceptibility to Fluoroquinolones Emerging in Italy. Microb Drug Resist 2004; 10:209-17. [PMID: 15383164 DOI: 10.1089/mdr.2004.10.209] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Fifteen Streptococcus pneumoniae clinical isolates with reduced fluoroquinolone susceptibility (defined as a ciprofloxacin MIC of > or = 4 microg/ml), all collected in Italy in 2000-2003, were typed and subjected to extensive molecular characterization to define the contribution of drug target alterations and efflux mechanisms to their resistance. Serotyping and pulsed-field gel electrophoresis analysis indicated substantial genetic unrelatedness among the 15 isolates, suggesting that the new resistance traits arise in multiple indigenous strains rather than through clonal dissemination. Sequencing of the quinolone resistance-determining regions of gyrA, gyrB, parC, and parE demonstrated that point mutations producing single amino acid changes were more frequent in topoisomerase IV (parC mutations in 14 isolates and parE mutations in 13) than in DNA gyrase subunits (gyrA mutations in 7 isolates and no gyrB mutations observed). No isolate displayed a quinolone efflux system susceptible to carbonyl cyanide m-chlorophenylhydrazone; conversely, four-fold or greater MIC reductions in the presence of reserpine were observed in all 15 isolates with ethidium bromide, in 13 with ulifloxacin, in 9 with ciprofloxacin, in 5 with norfloxacin, and in none with five other fluoroquinolones. The effect of efflux pump activity on the level and profile of fluoroquinolone resistance in our strains was minor compared with that of target site modifications. DNA mutations and/or efflux systems other than those established so far might contribute to the fluoroquinolone resistance expressed by our strains. Susceptibility profiles to nonquinolone class antibiotics and resistance-associated phenotypic and genotypic characteristics were also determined and correlated with fluoroquinolone resistance. A unique penicillin-binding protein profile was observed in all five penicillin-resistant isolates, whereas the same PBP profile as S. pneumoniae R6 was exhibited by all six penicillin-susceptible isolates. This is the first attempt to molecularly characterize clinical isolates of S. pneumoniae with reduced susceptibility to fluoroquinolones emerging in Italy.
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Affiliation(s)
- Maria Pia Montanari
- Department of Microbiology and Biomedical Sciences, Polytechnic University of Marche Medical School, 60131 Ancona, Italy
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Oh WS, Suh JY, Song JH, Ko KS, Jung SI, Peck KR, Lee NY, Yang Y, Chongthaleong A, Chiu CH, Kamarulzaman A, Parasakthi N, Lalitha MK, Perera J, Yee TT, Kumarasinghe G, Carlos CC. Fluoroquinolone Resistance in Clinical Isolates ofStreptococcus pneumoniaefrom Asian Countries: ANSORP Study. Microb Drug Resist 2004; 10:37-42. [PMID: 15140392 DOI: 10.1089/107662904323047781] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Seventeen clinical isolates of Streptococcus pneumoniae showing reduced susceptibility to ciprofloxacin (MIC >/= 4 micro g/ml) collected from eight different Asian countries were analyzed by antimicrobial susceptibility, serotyping, pulsed-field gel electrophoresis (PFGE), and DNA sequencing of the quinolone resistance-determining regions (QRDRs) in gyrA, gyrB, parC, and parE. All isolates but one showed more than one amino acid alteration in QRDRs of four responsible genes. Ile460 --> Val in parE was the most common mutation. Data suggest that Lys137 --> Asn in parC may be a primary step in the development of high-level and multiple FQ resistance. An additional mutation of Ser81 --> Phe in gyrA resulted in high-level resistance to ciprofloxacin, levofloxacin, and gatifloxacin, whereas Ser79 --> Phe in parC may exert an important role in the development of moxifloxacin resistance. Two novel amino acid changes in gyrB, Ala390 --> Val and Asn423 --> Thr, were found. Data from PFGE suggest an introduction and local spread of multiple resistant Spain(23F)-1 clone in Hong Kong, but isolates from other Asian countries were not related to this clone.
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Affiliation(s)
- Won Sup Oh
- Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, Korea
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Zhanel GG, Noreddin AM. Fluoroquinolone AUIC break points and the link to bacterial killing rates: in vitro models. Ann Pharmacother 2003; 37:1331-4. [PMID: 12921519 DOI: 10.1345/aph.1d095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Johnson CN, Benjamin Jr WH, Moser SA, Hollingshead SK, Zheng X, Crain MJ, Nahm MH, Waites KB. Genetic relatedness of levofloxacin-nonsusceptible Streptococcus pneumoniae isolates from North America. J Clin Microbiol 2003; 41:2458-64. [PMID: 12791865 PMCID: PMC156496 DOI: 10.1128/jcm.41.6.2458-2464.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We characterized 32 levofloxacin-nonsusceptible Streptococcus pneumoniae (LNSP) isolates obtained from a broad geographic region of North America over a 5-year period by using capsular serotypes, antimicrobial susceptibility profiles, BOX-PCR, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Sixteen international clones identified by the Pneumococcal Molecular Epidemiology Network also were included for comparison. Fifteen serotypes were represented, with serogroups 6, 9, 14, 19, and 23 accounting for 63% of isolates. Among isolates whose quinolone resistance-determining regions were sequenced, all contained gyrA and parC point mutations. Sixty-three percent were penicillin susceptible, and 84% were erythromycin susceptible. BOX-PCR analysis identified 39 different band patterns among 32 LNSP and 16 international clones and grouped 16 isolates, including 2 international clones, into seven unrelated groups of 2 to 4 isolates each. PFGE analysis identified 35 different band patterns among 32 LNSP and 16 international clones and grouped 21 isolates, including 3 international clones, into eight unrelated groups of 2 to 6 isolates each. MLST performed on 10 isolates identified five allelic profiles and separated 9 isolates into four groups of 2 to 3 isolates each. Overall, each typing method indicated that the LNSP were heterogeneous and that resistance to fluoroquinolones was not closely associated with a particular serotype or with coresistance to other antimicrobial classes and suggests that LNSP have likely arisen through independent mutational events as a result of selective pressure. However, seven LNSP were found to be related to three international clones by PFGE.
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Affiliation(s)
- Crystal N Johnson
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35249, USA
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Biedenbach DJ, Jones RN. Five-year analysis of Haemophilus influenzae isolates with reduced susceptibility to fluoroquinolones: prevalence results from the SENTRY antimicrobial surveillance program. Diagn Microbiol Infect Dis 2003; 46:55-61. [PMID: 12742320 DOI: 10.1016/s0732-8893(03)00016-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The appearance of resistance or reduced susceptibility to fluoroquinolones among Hemophilus influenzae has been documented for nearly a decade. Over this time, the use of fluoroquinolones for the treatment of respiratory infections including commonly isolated bacterial causes of community-acquired infections has markedly increased. The documentation of resistance to fluoroquinolones among Streptococcus pneumoniae and H. influenzae has also become more prevalent as measured by peer-reviewed publications. During 1997-2001, a total of 11,355 H. influenzae isolates were tested by reference broth microdilution methods from strains collected by the SENTRY Antimicrobial Surveillance Program (American and European medical centers). Strains with reduced susceptibility to fluoroquinolones (RSF) were detected during all five study years at an overall rate of 0.15%. Among the tested compounds, sitafloxacin (MIC(50,) 0.03 microg/ml) was the most potent agent against the RSF strains, followed by gemifloxacin (0.12 microg/ml) > garenoxacin = grepafloxacin = levofloxacin = moxifloxacin = trovafloxacin (0.5 microg/ml) > ciprofloxacin = sparfloxacin (1 microg/ml). Gene sequencing of the quinolone resistance determining region and epidemiologic typing of 30 RSF isolates showed diverse mutational events in gyr A and par C and multiple pulsed-field gel electrophoresis (PFGE) patterns among strains that was not consistent with clonal dissemination. Continued surveillance by global or national networks should continue to monitor for H. influenzae isolates that are refractory to fluoroquinolone therapy.
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