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Role of Synonymous Mutations in the Evolution of TEM β-Lactamase Genes. Antimicrob Agents Chemother 2021; 65:AAC.00018-21. [PMID: 33820762 DOI: 10.1128/aac.00018-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/23/2021] [Indexed: 01/25/2023] Open
Abstract
Nonsynonymous mutations are well documented in TEM β-lactamases. The resulting amino acid changes often alter the conferred phenotype from broad spectrum (2b) conferred by TEM-1 to extended spectrum (2be), inhibitor resistant (2br), or both extended spectrum and inhibitor resistant (2ber). The encoding bla TEM genes also deviate in numerous synonymous mutations, which are not well understood. bla TEM-3 (2be), bla TEM-33 (2br), and bla TEM-109 (2ber) were studied in comparison to bla TEM-1 bla TEM-33 was chosen for more detailed studies because it deviates from bla TEM-1 by a single nonsynonymous mutation and three additional synonymous mutations. Genes encoding the enzymes with only nonsynonymous or all (including synonymous) mutations plus all permutations between bla TEM-1 and bla TEM-33 were expressed in Escherichia coli cells. In disc diffusion assays, genes encoding TEM-3, TEM-33, and TEM-109 with all synonymous mutations resulted in higher resistance levels than genes without synonymous mutations. Disc diffusion assays with the 16 genes carrying all possible nucleotide change combinations between bla TEM-1 and bla TEM-33 indicated different susceptibilities for different variants. Nucleotide BLAST searches did not identify genes without synonymous mutations but did identify some without nonsynonymous mutations. Energies of possible secondary mRNA structures calculated with mfold are generally higher with synonymous mutations, suggesting that their role could be to destabilize the mRNA and facilitate its unfolding for efficient translation. In summary, our data indicate that transition from bla TEM-1 to other variant genes by simply acquiring the nonsynonymous mutations is not favored. Instead, synonymous mutations seem to support the transition to other variant genes with nonsynonymous mutations leading to different phenotypes.
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Wootton M, MacGowan AP, Howe RA. Towards better antimicrobial susceptibility testing: impact of the Journal of Antimicrobial Chemotherapy. J Antimicrob Chemother 2017; 72:323-329. [PMID: 28115501 DOI: 10.1093/jac/dkw494] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Susceptibility testing of bacteria is one of the most important tests performed in a clinical microbiology laboratory. Improvements in laboratory techniques, especially the move towards standardized susceptibility testing, has provided better consistency and accuracy of testing. When used in conjunction with the most recently developed interpretative criteria, the result is better prediction of the outcome of antimicrobial therapy for infected patients. Throughout the last four decades this Journal has published numerous articles evidencing improvements and new techniques, a valuable source of information for microbiology laboratories.
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Affiliation(s)
- Mandy Wootton
- Welsh Antimicrobial Resistance Programme, Public Health Wales, University Hospital of Wales, Cardiff CF14 4XW, UK
| | - Alasdair P MacGowan
- Bristol Centre for Antimicrobial Research & Evaluation (BCARE), Department of Infection Sciences, Pathology Sciences Building, Southmead Hospital, Westbury-on-Trym, Bristol BS10 5NB, UK
| | - Robin A Howe
- Welsh Antimicrobial Resistance Programme, Public Health Wales, University Hospital of Wales, Cardiff CF14 4XW, UK
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Banche G, Allizond V, Mandras N, Tullio V, Cuffini AM. Host immune modulation by antimicrobial drugs: current knowledge and implications for antimicrobial chemotherapy. Curr Opin Pharmacol 2014; 18:159-66. [DOI: 10.1016/j.coph.2014.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/18/2014] [Accepted: 07/21/2014] [Indexed: 12/29/2022]
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Bosnar M, Kragol G, Koštrun S, Vujasinović I, Bošnjak B, Bencetić Mihaljević V, Marušić Ištuk Z, Kapić S, Hrvačić B, Brajša K, Tavčar B, Jelić D, Glojnarić I, Verbanac D, Čulić O, Padovan J, Alihodžić S, Eraković Haber V, Spaventi R. N′-Substituted-2′-O,3′-N-carbonimidoyl Bridged Macrolides: Novel Anti-inflammatory Macrolides without Antimicrobial Activity. J Med Chem 2012; 55:6111-23. [DOI: 10.1021/jm300356u] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Martina Bosnar
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Goran Kragol
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Sanja Koštrun
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Ines Vujasinović
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Berislav Bošnjak
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | | | - Zorica Marušić Ištuk
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Samra Kapić
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Boška Hrvačić
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Karmen Brajša
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Branka Tavčar
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Dubravko Jelić
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Ines Glojnarić
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Donatella Verbanac
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Ognjen Čulić
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Jasna Padovan
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Sulejman Alihodžić
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Vesna Eraković Haber
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
| | - Radan Spaventi
- GlaxoSmithKline Research Centre
Zagreb, Prilaz baruna Filipovića 29, Zagreb, Croatia
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Discovery of novel ureas and thioureas of 3-decladinosyl-3-hydroxy 15-membered azalides active against efflux-mediated resistant Streptococcus pneumoniae. Bioorg Med Chem Lett 2011; 21:853-6. [DOI: 10.1016/j.bmcl.2010.11.079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 11/05/2010] [Accepted: 11/16/2010] [Indexed: 11/18/2022]
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Chalmers JD, Al-Khairalla M, Short PM, Fardon TC, Winter JH. Proposed changes to management of lower respiratory tract infections in response to the Clostridium difficile epidemic. J Antimicrob Chemother 2010; 65:608-18. [PMID: 20179023 DOI: 10.1093/jac/dkq038] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Clostridium difficile infection (CDI) remains a major healthcare problem associated with antibiotic use in hospitals. Recent years have seen a dramatic increase in the incidence of CDI in the UK and internationally. Lower respiratory tract infections (LRTIs) are the leading indication for antibiotic prescription in hospitals and are therefore a critical battleground in the fight against inappropriate antibiotic use and healthcare-associated infections. This article reviews the evidence for interventions to reduce CDI in hospitalized patients with LRTIs. Reducing prescriptions of cephalosporins and fluoroquinolones in favour of penicillin-based regimens and increased use of tetracyclines have been proposed. Expanding outpatient management of LRTIs and reducing length of hospital stay will limit patient exposure to the healthcare environment in which C. difficile is most easily acquired. Intravenous (iv) broad-spectrum antibiotics are often prescribed when narrower spectrum, oral antimicrobials would be equally effective and, in a proportion of patients, antibiotic therapy is used unnecessarily. Shorter antibiotic regimes may be as effective as prolonged therapy and reduce antibiotic-related complications. Early switch from iv to oral therapy allows simpler antibiotic regimens and facilitates early discharge from hospital. Simple improvements in the management of LRTIs have the potential to reduce the incidence of healthcare-associated infections.
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Affiliation(s)
- James D Chalmers
- MRC Centre for Inflammation Research, Queens Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
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New semiphysiological absorption model to assess the pharmacodynamic profile of cefuroxime axetil using nonparametric and parametric population pharmacokinetics. Antimicrob Agents Chemother 2009; 53:3462-71. [PMID: 19528278 DOI: 10.1128/aac.00054-09] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cefuroxime axetil is widely used to treat respiratory tract infections. We are not aware of a population pharmacokinetic (PK) model for cefuroxime axetil. Our objectives were to develop a semiphysiological population PK model and evaluate the pharmacodynamic profile for cefuroxime axetil. Twenty-four healthy volunteers received 250 mg oral cefuroxime as a suspension after a standardized breakfast. Liquid chromatography-tandem mass spectrometry was used for drug analysis, NONMEM and S-ADAPT (results reported) were used for parametric population PK modeling, and NPAG was used for nonparametric population PK modeling. Monte Carlo simulations were used to predict the duration for which the non-protein-bound-plasma concentration was above the MIC (fT(>MIC)). A model with one disposition compartment, a saturable and time-dependent drug release from the stomach, and fast drug absorption from the intestine yielded precise (r > 0.992) and unbiased curve fits and an excellent predictive performance. The apparent clearance was 21.7 liters/h (19.8% coefficient of variation [CV]) and the volume of distribution 38.7 liters (18.3% CV). Robust (>or=90%) probabilities of target attainment (PTAs) were achieved by 250 mg cefuroxime given every 12 h (q12h) or q8h for MICs of <or=0.375 mg/liter or <or=0.5 mg/liter, respectively, for the bacteriostasis target fT(>MIC) of >or=40% and for MICs of <or=0.094 mg/liter or <or=0.375 mg/liter, respectively, for the near-maximal-killing target fT(>MIC) of >or=65%. For the >or=40% fT(>MIC) target, the PTAs for 250 mg cefuroxime q12h were >or=97.8% for Streptococcus pyogenes and penicillin-susceptible Streptococcus pneumoniae. Cefuroxime at 250 mg q12h or q8h achieved PTAs below 73% or 92%, respectively, for Haemophilus influenzae, Moraxella catarrhalis, and penicillin-intermediate S. pneumoniae for susceptibility data from various countries. Depending on the MIC distribution, 250 mg oral cefuroxime q8h instead of q12h should be considered, especially for more-severe infections that require near-maximal killing by cefuroxime.
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Abstract
Doxycycline is a member of the tetracycline class of antibiotics and has been used clinically for more than 40 years. It is a well-tolerated drug that is bacteriostatic and acts via the inhibition of bacterial ribosomes. It is generally given at a dose of 100-mg daily or twice daily. It is well absorbed and has generally good tissue penetration. The serum half-life is 18-22 hours and dosage does not need to be adjusted in the presence of renal or hepatic impairment. Major side effects are gastro-intestinal and dermatological and it is generally contra-indicated in pregnancy or childhood because of concerns about discolouration of developing teeth and potential effects on growing bones. Drug interactions are not common although can occur with the concomitant use of methotrexate and the oral contraceptive pill, and its absorption can be reduced by the co-administration with some antacids and iron preparations. It has activity against many organisms, including Gram-positives, Gram-negatives and atypical bacteria. In addition, it appears to have some potentially clinically useful anti-inflammatory properties.
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Affiliation(s)
- Natasha E. Holmes
- Department of Infectious Diseases, Austin Health, PO Box 5555, Heidelberg VIC 3084, Australia
| | - Patrick G.P. Charles
- Department of Infectious Diseases, Austin Health, PO Box 5555, Heidelberg VIC 3084, Australia
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Cuffini AM, Tullio V, Banche G, Allizond V, Mandras N, Roana J, Scalas D, Carlone NA. The erythromycin-resistance in S. pyogenes does not limit the human polymorphonuclear cell antimicrobial activity. Int J Immunopathol Pharmacol 2009; 22:239-42. [PMID: 19309572 DOI: 10.1177/039463200902200127] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In order to highlight the potential erythromycin immunomodulatory properties related to different antibiotic resistance patterns in Streptococcus spp., we evaluated the influence of the macrolide on the PMNs primary functions against erythromycin-susceptible (Ery-S) and erythromycin-resistant (Ery-R) S. pyogenes strains. A total of 438 S. pyogenes were isolated over the period 2005-2007. On the basis of the triple disk testing, 345 out of 438 S. pyogenes isolates were Ery-S and 93 were Ery-R; among the resistant strains, 65 displayed the cMLSB phenotype, 23 had the M phenotype and 5 had iMLSB phenotype. Concerning antibacterial activity of PMNs, our results showed that erythromycin did not modify bacterial uptake, but significantly increased the phagocyte intracellular killing, compared with controls, for both Ery-S and Ery-R strains. Consequently, this report underlines that in immunocompetent hosts the dichotomy between the in vitro resistance and clinical trial data for antimicrobial agents should be thoroughly re-evaluated.
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Vardakas KZ, Siempos II, Grammatikos A, Athanassa Z, Korbila IP, Falagas ME. Respiratory fluoroquinolones for the treatment of community-acquired pneumonia: a meta-analysis of randomized controlled trials. CMAJ 2008; 179:1269-77. [PMID: 19047608 PMCID: PMC2585120 DOI: 10.1503/cmaj.080358] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND We investigated whether the use of respiratory fluoroquinolones was associated with better clinical outcomes compared with the use of macrolides and beta- lactams among adults with pneumonia. METHODS We searched PubMed, Current Contents, Scopus, EMBASE, ClinicalTrials.gov and Cochrane with no language restrictions. Two reviewers independently extracted data from published trials that compared fluoroquinolones (levofloxacin, moxifloxacin, gemifloxacin) with macrolides or beta-lactams or both. A meta-analysis was performed with the clinical outcomes of mortality, treatment success and adverse outcomes. RESULTS We included 23 trials in our meta-analysis. There was no difference in mortality among patients who received fluoroquinolones or the comparator antibiotics (OR 0.85, 95% CI 0.65-1.12). Pneumonia resolved in more patients who received fluoroquinolones compared with the comparator antibiotics for the included outcomes in the intention-to-treat population (OR 1.17, 95% CI 1.00-1.36), clinically evaluable population (OR 1.26, 95% CI 1.06-1.50) and the microbiologically assessed population (OR 1.67, 95% CI 1.28-2.20). Fluoroquinolones were more effective than a combination of beta-lactam and macrolide (OR 1.39, 95% CI 1.02-1.90). They were also more effective for patients with severe pneumonia (OR 1.84, 95% CI 1.02-3.29), those who required admission to hospital (OR = 1.30, 95% CI 1.04-1.61) and those who required intravenous therapy (OR = 1.44, 15% CI 1.13-1.85). Fluoroquinolones were more effective than beta-lactam and macrolide in open-label trials (OR = 1.35, 95% CI 1.08-1.69) but not in blinded randomized controlled trials (OR = 1.13, 95% CI 0.85-1.50). INTERPRETATION Fluoroquinolones were associated with higher success of treatment for severe forms of pneumonia; however, a benefit in mortality was not evident. A randomized controlled trial that includes patients with severe pneumonia with or without bacteremia is needed.
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Farrell DJ, Felmingham D, Shackcloth J, Williams L, Maher K, Hope R, Livermore DM, George RC, Brick G, Martin S, Reynolds R. Non-susceptibility trends and serotype distributions among Streptococcus pneumoniae from community-acquired respiratory tract infections and from bacteraemias in the UK and Ireland, 1999 to 2007. J Antimicrob Chemother 2008; 62 Suppl 2:ii87-95. [DOI: 10.1093/jac/dkn355] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Ludlam HA, Enoch DA. Doxycycline or moxifloxacin for the management of community-acquired pneumonia in the UK? Int J Antimicrob Agents 2008; 32:101-5. [PMID: 18571380 DOI: 10.1016/j.ijantimicag.2008.02.003] [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] [Received: 01/07/2008] [Accepted: 02/04/2008] [Indexed: 11/17/2022]
Abstract
Macrolide monotherapy is currently recommended as first-line treatment of mild-to-moderate community-acquired pneumonia (CAP) in penicillin-intolerant/allergic individuals in the UK. However, resistance rates among the commonest cause, Streptococcus pneumoniae, now exceed 10% in the UK and a review of alternative agents is therefore timely. This review considers the relative merits of two agents, doxycycline and moxifloxacin, which are candidates to replace macrolides for second-line therapy of non-severe CAP.
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Affiliation(s)
- H A Ludlam
- Clinical Microbiology & Public Health Laboratory, Box 236, Addenbrooke's Hospital, Cambridge University NHS Foundation Trust, Hills Road, Cambridge, UK
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Lode HM. Rational antibiotic therapy and the position of ampicillin/sulbactam. Int J Antimicrob Agents 2008; 32:10-28. [PMID: 18539004 DOI: 10.1016/j.ijantimicag.2008.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2008] [Accepted: 02/04/2008] [Indexed: 01/22/2023]
Abstract
In the current context of increasing antimicrobial resistance, it is important to use antibiotics rationally and to re-assess regularly the clinical usefulness of commonly used agents. This review focuses on the efficacy of the beta-lactam ampicillin co-administered with the beta-lactamase inhibitor sulbactam, either parenterally (ampicillin/sulbactam) or orally (sultamicillin), for the treatment of bacterial infections. Clinical findings from the past decade confirm the results of numerous older studies and together provide good evidence to support the continued use of ampicillin/sulbactam and sultamicillin in hospital- and community-acquired infections both in adults and children. This is also recognised in recent published national and international guidelines, many of which recommend ampicillin/sulbactam as first-line therapy for various respiratory and skin infections.
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Affiliation(s)
- Hartmut M Lode
- Research Centre for Medical Studies, Institute of Clinical Pharmacology, Charité Universitätsmedizin Berlin, Hohenzollerndamm 2, Berlin, Germany.
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Shen XZ, Lu Q, Deng L, Yu S, Zhang H, Deng Q, Jiang M, Hu Y, Yao KH, Yang YH. Resistance of Haemophilus influenzae isolates in children under 5 years old with acute respiratory infections in China between 2000 and 2002. J Int Med Res 2007; 35:554-63. [PMID: 17697534 DOI: 10.1177/147323000703500416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This prospective, three-centre study tested for antimicrobial susceptibility in 898 isolates of Haemophilus influenzae between 2000 and 2002 in Chinese children aged under 5 years with acute upper respiratory tract infection. The average incidence of beta-lactamase production was 12.0%. Overall, 88.0% of isolates were susceptible to ampicillin, 100.0% were susceptible to amoxicillin/clavulanic acid, ceftriaxone, cefuroxime and azithromycin, and 99.0% were susceptible to ciprofloxacin. Isolates from Beijing and Shanghai had a lower susceptibility to tetracycline (57.0% and 61.0%, respectively) compared with those from Guangzhou (81.0%), while trimethoprim/sulfamethoxazole susceptibilities in Shanghai (47.0%) and Guangzhou (54.0%) were significantly higher than in Beijing (35.0%). A total of 34.5% of all the isolates were susceptible to all eight of these antimicrobial agents and 12.8% were multi-drug resistant. Ampicillin resistance increased over the duration of the study. These findings show that beta-lactamase production and ampicillin resistance among isolates from Chinese children with upper respiratory tract infection are increasing, and highlight the strong correlation between ampicillin resistance and resistance to cefaclor, chloramphenicol and tetracycline in H. influenzae isolates.
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Affiliation(s)
- X Z Shen
- Beijing Children's Hospital Affiliated to Capital Medical University, Beijing, China
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Felmingham D, Cantón R, Jenkins SG. Regional trends in β-lactam, macrolide, fluoroquinolone and telithromycin resistance among Streptococcus pneumoniae isolates 2001–2004. J Infect 2007; 55:111-8. [PMID: 17568680 DOI: 10.1016/j.jinf.2007.04.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 04/13/2007] [Accepted: 04/17/2007] [Indexed: 11/13/2022]
Abstract
OBJECTIVES To determine global antibacterial resistance rates among community-acquired isolates of Streptococcus pneumoniae. METHODS Between 2001 and 2004, 20,142 S. pneumoniae isolates from 151 centres in 40 countries were collected and tested for susceptibility to common antibacterials in the PROTEKT surveillance study. RESULTS The prevalence of beta-lactam and macrolide resistance did not change, but there was marked geographic variability. The most common macrolide resistance mechanism was ribosomal methylation mediated by erm(B), except in Canada, Greece and the USA where drug efflux mediated by mef(A) was predominant. The erythromycin minimum inhibitory concentration for mef(A) isolates increased significantly (P<0.001; chi2 test). The global prevalence of macrolide-resistant isolates positive for both erm(B) and mef(A) was 12.0% in 2003-2004; erm(B)+mef(A) strains were particularly common in South Korea (40.8%), South Africa (46.4%) and the USA (29.6%). Telithromycin was the most active antibacterial tested. Over the studied period, > or = 99.7% of all isolates and > 99% of erythromycin-resistant isolates, irrespective of genotype, were susceptible to telithromycin. CONCLUSIONS These results confirm the high worldwide prevalence of resistance to commonly used antibacterial agents and multiple resistance phenotypes among clinical isolates of S. pneumoniae and suggest that high-level macrolide resistance is continuing to increase in most countries.
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