Category Archives: J Antimicrob Chemother

Effects of prophylactic antibiotics on patients with stable COPD: a systematic review and meta-analysis of randomized controlled trials.

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Effects of prophylactic antibiotics on patients with stable COPD: a systematic review and meta-analysis of randomized controlled trials.
J Antimicrob Chemother. 2018 Sep 04;:
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Use of gentamicin-impregnated beads or sponges in the treatment of early acute periprosthetic joint infection: a propensity score analysis.

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Use of gentamicin-impregnated beads or sponges in the treatment of early acute periprosthetic joint infection: a propensity score analysis.
J Antimicrob Chemother. 2018 Sep 05;:
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Characterization of the population structure, drug resistance mechanisms and plasmids of the community-associated Enterobacter cloacae complex in China.

Characterization of the population structure, drug resistance mechanisms and plasmids of the community-associated Enterobacter cloacae complex in China.

J Antimicrob Chemother. 2017 Oct 27;:

Authors: Zhou K, Yu W, Cao X, Shen P, Lu H, Luo Q, Rossen JWA, Xiao Y

Abstract
Objectives: To investigate the population structure, drug resistance mechanisms and plasmids of community-associated Enterobacter cloacae complex (CA-ECC) isolates in China.
Methods: Sixty-two CA-ECC isolates collected from 31 hospitals across China were typed by hsp60 typing and MLST. ESBL and AmpC-overexpression phenotype was determined by double-disc synergy test. Replicon typing and conjugation were performed for plasmid analysis. All ESBL-positive isolates and representative conjugants were subjected to detailed characterization by WGS.
Results: Enterobacter hormaechei and Enterobacter kobei were predominant in our collections. MLST distinguished 46 STs with a polyclonal structure. ST591 was the most prevalent clone detected in northern China. Twenty-two isolates (35.5%) were ESBL positive and half of them were E. kobei. ESBL positivity was related to ESBL production (15/22) and to AmpC overexpression (18/22). Core-genome phylogenetic analysis identified intra- and inter-regional dissemination of ESBL-producing E. kobei clones. ESBL producers were exclusively classified as E. hormaechei and E. kobei, and blaCTX-M-3 was the most prevalent ESBL genotype (10/15) detected in four different environments. In the ESBL-positive population, the ESBL producers encoded more drug resistance genes (8-24 genes) by carrying more plasmids (1-3 plasmids) than the non-ESBL-producing isolates, resulting in an inter-group difference in drug susceptibilities. IncHI-type plasmids were prevalent in the ESBL producers (12/15). All IncHI2-type plasmids (n = 11) carried ESBL genes and shared a similar backbone to p09-036813-1A_261 recovered from Salmonella enterica in Canada.
Conclusions: The species-specific distribution, species-dependent ESBL mechanism and endemic plasmids identified in our study highlight the necessity for tailored surveillance of CA-ECC in the future.

PMID: 29088362 [PubMed – as supplied by publisher]

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Whole-genome analysis of an oxacillin-susceptible CC80 mecA-positive Staphylococcus aureus clinical isolate: insights into the mechanisms of cryptic methicillin resistance.

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Whole-genome analysis of an oxacillin-susceptible CC80 mecA-positive Staphylococcus aureus clinical isolate: insights into the mechanisms of cryptic methicillin resistance.

J Antimicrob Chemother. 2015 Jul 20;

Authors: Sabat AJ, Pournaras S, Akkerboom V, Tsakris A, Grundmann H, Friedrich AW

Abstract
OBJECTIVES: The mec and bla systems, among other genetic factors, are critical in regulating the expression of methicillin resistance in Staphylococcus aureus. We examined by WGS a naturally occurring oxacillin-susceptible mecA-positive S. aureus isolate to identify the mechanism conferring oxacillin susceptibility.
METHODS: The mecA-positive oxacillin-susceptible S. aureus isolate GR2 (penicillin and oxacillin MICs 0.094 and 1 mg/L, respectively), belonging to clonal complex 80, was characterized. DNA fragment libraries were sequenced on Roche 454 and Illumina MiSeq sequencers and de novo assembly of the genome was generated using SeqMan NGen software. Plasmid curing was conducted by SDS treatment. Expression of mecA was quantified without/with β-lactam pressure.
RESULTS: The genome of GR2 consisted of a 2 792 802 bp chromosome and plasmids pGR2A (28 895 bp) and pGR2B (2473 bp). GR2 carried SCCmec type IV, with a truncated/non-functional mecR1 gene and no mecI. A single copy of the bla system, with an organization unique for S. aureus, was found, harboured by plasmid pGR2A. Particularly, the blaZ gene was orientated like its regulatory genes, blaI and blaR1, and a gene encoding transposase IS66 was integrated between blaZ and the regulatory genes deleting the 5′-end of blaR1; blaI, encoding blaZ/mecA repressor, was intact. After plasmid loss, GR2 became penicillin and oxacillin resistant (MICs 0.5 and 6 mg/L, respectively).
CONCLUSIONS: We can conclude that after exposure to β-lactams, the non-functional BlaR1 does not cleave the mecA repressor BlaI, derepression does not occur and mecA is not efficiently expressed. Removal of the bla system after curing of pGR2A allows constitutive expression of mecA, resulting in oxacillin and penicillin resistance.

PMID: 26198147 [PubMed – as supplied by publisher]

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Efficacy of tenofovir and efavirenz in combination with lamivudine or emtricitabine in antiretroviral-naive patients in Europe.

Efficacy of tenofovir and efavirenz in combination with lamivudine or emtricitabine in antiretroviral-naive patients in Europe.

J Antimicrob Chemother. 2015 Mar 3;

Authors: Swartz JE, Vandekerckhove L, Ammerlaan H, de Vries AC, Begovac J, Bierman WF, Boucher CA, van der Ende ME, Grossman Z, Kaiser R, Levy I, Mudrikova T, Paredes R, Perez-Bercoff D, Pronk M, Richter C, Schmit JC, Vercauteren J, Zazzi M, Židovec Lepej S, De Luca A, Wensing AM, on behalf of the European Society for translational Antiviral Research (ESAR)

Abstract
BACKGROUND: The combination of tenofovir and efavirenz with either lamivudine or emtricitabine (TELE) has proved to be highly effective in clinical trials for first-line treatment of HIV-1 infection. However, limited data are available on its efficacy in routine clinical practice.
METHODS: A multicentre cohort study was performed in therapy-naive patients initiating ART with TELE before July 2009. Efficacy was studied using ITT (missing or switch = failure) and on-treatment (OT) analyses. Genotypic susceptibility scores (GSSs) were determined using the Stanford HIVdb algorithm.
RESULTS: Efficacy analysis of 1608 patients showed virological suppression to <50 copies/mL at 48 weeks in 91.5% (OT) and 70.6% (ITT). Almost a quarter of all patients (22.9%) had discontinued TELE at week 48, mainly due to CNS toxicity. Virological failure within 48 weeks was rarely observed (3.3%, n = 53). In multilevel, multivariate analysis, infection with subtype B (P = 0.011), baseline CD4 count <200 cells/mm³ (P < 0.001), GSS <3 (P = 0.002) and use of lamivudine (P < 0.001) were associated with a higher risk of virological failure. After exclusion of patients using co-formulated compounds, virological failure was still more often observed with lamivudine. Following virological failure, three-quarters of patients switched to a PI-based regimen with GSS <3. After 1 year of second-line therapy, viral load was suppressed to <50 copies/mL in 73.5% (OT).
CONCLUSIONS: In clinical practice, treatment failure on TELE regimens is relatively frequent due to toxicity. Virological failure is rare and more often observed with lamivudine than with emtricitabine. Following virological failure on TELE, PI-based second-line therapy was often successful despite GSS <3.

PMID: 25740950 [PubMed – as supplied by publisher]

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Genome-wide analysis reveals two novel mosaic regions containing an ACME with an identical DNA sequence in the MRSA ST398-t011 and MSSA ST8-t008 isolates.

Genome-wide analysis reveals two novel mosaic regions containing an ACME with an identical DNA sequence in the MRSA ST398-t011 and MSSA ST8-t008 isolates.
J Antimicrob Chemother. 2015 Jan 28;
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OXY-2-15, a novel variant showing increased ceftazidime hydrolytic activity.

OXY-2-15, a novel variant showing increased ceftazidime hydrolytic activity.

J Antimicrob Chemother. 2015 Jan 27;

Authors: Nijhuis RH, Oueslati S, Zhou K, Bosboom RW,…

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Using an index-based approach to assess the population-level appropriateness of empirical antibiotic therapy.

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Using an index-based approach to assess the population-level appropriateness of empirical antibiotic therapy.
J Antimicrob Chemother. 2014 Aug 27;
Authors: Ciccolini M, Spoorenberg V, Geerlings SE, Pr… Continue reading

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Systemic absorption of nasally administered tobramycin and colistin in patients with cystic fibrosis.

Systemic absorption of nasally administered tobramycin and colistin in patients with cystic fibrosis.

J Antimicrob Chemother. 2014 Jul 11;

Authors: Berkhout MC, van…

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Five year results of an international proficiency testing programme for measurement of antifungal drug concentrations.

Five year results of an international proficiency testing programme for measurement of antifungal drug concentrations.

J Antimicrob Chemother. 2014 Jul 7;

Authors: Lempers VJ, Alffenaar JW, Touw DJ, Burger DM, Uges DR, Aarnoutse RE, Brüggemann RJ

Abstract
OBJECTIVES: Since 2007 the Dutch Association for Quality Assessment in Therapeutic Drug Monitoring (KKGT) has organized an international interlaboratory proficiency testing (PT) programme for measurement of antifungal drugs in plasma. We describe the 5 year results of the laboratories’ performance.
METHODS: Twice a year, laboratories received a set of blind plasma samples containing low or high concentrations of fluconazole, itraconazole, hydroxyitraconazole, posaconazole, voriconazole and flucytosine. Participating laboratories were asked to report their results within 6 weeks after dispatch and provide details of their analytical methods. Results deviating >20% from the weighed-in concentration were considered inaccurate. Four-way ANOVA was performed to assess the effect of antifungal drug measured, concentration, analytical method and performing laboratory on the absolute inaccuracy. In 2012, a questionnaire based on the CLSI guidelines was dispatched with the request to provide input on sources of error.
RESULTS: Fifty-seven laboratories (13 countries) reported 2251 results (287 fluconazole, 451 itraconazole, 348 hydroxyitraconazole, 402 posaconazole, 652 voriconazole and 111 flucytosine) in 5 years. Analyses were performed using HPLC (55.0%), LC-MS(/MS) (43.4%), UPLC (1.4%) or GC-MS (0.2%). Overall, 432 (19.2%) analyses were inaccurate. The performing laboratory was the only factor clearly associated with inaccuracies. The questionnaire results indicated that laboratories encounter significant problems analysing low concentrations (15.4% of all inaccuracies).
CONCLUSIONS: Results of the PT programme suggest that one out of five measurements is inaccurate. The performing laboratory is the main determinant of inaccuracy, suggesting that internal quality assurance is pivotal in preventing inaccuracies, irrespective of the antifungal drug measured, concentration and analytical equipment.

PMID: 25006236 [PubMed – as supplied by publisher]

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Frequent carriage of resistance mechanisms to β-lactams and biofilm formation in Haemophilus influenzae causing treatment failure and recurrent otitis media in young children.

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Frequent carriage of resistance mechanisms to β-lactams and biofilm formation in Haemophilus influenzae causing treatment failure and recurrent otitis media in young…

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Effect of pravastatin and fosinopril on recurrent urinary tract infections.

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Effect of pravastatin and fosinopril on recurrent urinary tract infections.

J Antimicrob Chemother. 2013 Mar;68(3):708-14

Authors: Pouwels KB, Visser ST,…

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Comment on: Daily 300 mg dose of linezolid for multidrug-resistant and extensively drug-resistant tuberculosis: updated analysis of 51 patients.

Comment on: Daily 300 mg dose of linezolid for multidrug-resistant and extensively drug-resistant tuberculosis: updated analysis of 51 patients.
J Antimicrob Chemother. 2012 Apr 27;
Authors: Bolhuis MS, van Altena R, Alffenaar… Continue reading

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