International Journal of Antimicrobial Agents

Editorial Board

2012-02-01

Introduction to the MRSA series of reviews

Ian Gould — 2011-12-23

Meticillin-resistant Staphylococcus aureus (MRSA) continues to cause major healthcare problems in most countries, both in hospitals and in the community. The introduction of new anti-MRSA antimicrobial agents allows for some complacency and attention has, to some extent, shifted to extreme resistance in Gram-negative organisms. We allow this at our peril. Although we now have good information on the measures necessary to control healthcare MRSA, even in endemic situations , very few countries have been able to implement the necessary control measures.

New insights into meticillin-resistant Staphylococcus aureus (MRSA) pathogenesis, treatment and resistance

2011-12-26

Abstract: Meticillin-resistant Staphylococcus aureus (MRSA) remains one of the principal multiply resistant bacterial pathogens causing serious healthcare-associated and community-onset infections. This paper reviews recent studies that have elucidated the virulence strategies employed by MRSA, key clinical trials of agents used to treat serious MRSA infections, and accumulating data regarding the implications of antibacterial resistance in MRSA for clinical success during therapy. Recent pre-clinical data support a species-specific role for Panton–Valentine leukocidin in the development of acute severe S. aureus infections and have elucidated other virulence mechanisms, including novel modes of internalisation, varying post-invasion strategies (featuring both upregulation and downregulation of virulence factors) and phenotypic switching. Recent double-blind, randomised, phase III/IV clinical trials have demonstrated the efficacy of linezolid and telavancin in hospital-acquired pneumonia (HAP) and complicated skin and skin-structure infections (cSSSIs) caused by MRSA. Tigecycline was non-inferior to imipenem/cilastatin in non-ventilator-associated HAP but was inferior in ventilator-associated pneumonia and has shown a higher rate of death than comparators on meta-analysis. Ceftaroline was clinically and microbiologically non-inferior to vancomycin/aztreonam in the treatment of MRSA cSSSI. Key resistance issues include a rise in vancomycin minimum inhibitory concentrations in MRSA, reports of clonal isolates with linezolid resistance mediated by acquisition of the chloramphenicol/florfenicol resistance gene, and case reports of daptomycin resistance resulting in clinical failure. Novel antimicrobial targets must be identified with some regularity or we will face the risk of untreatable S. aureus infections.

Emergence of resistance to carbapenems in Acinetobacter baumannii in Europe: clinical impact and therapeutic options

Marie Kempf, Jean-Marc Rolain — 2011-11-23

Abstract: Despite having a reputation of low virulence, Acinetobacter baumannii is an emerging multidrug-resistant (MDR) pathogen responsible for community- and hospital-acquired infections that are difficult to control and treat. Interest in this pathogen emerged about one decade ago because of its natural MDR phenotype, its capability of acquiring new mechanisms of resistance and the existence of nosocomial outbreaks. Recent advances in molecular biology, including full genome sequencing of several A. baumannii isolates, has led to the discovery of the extraordinary plasticity of their genomes, which is linked to their great propensity to adapt to any environment, including hospitals. In this context, as well as the increasing antimicrobial resistance amongst A. baumannii isolates to the last-line antibiotics carbapenems and colistin, therapeutic options are very limited or absent in some cases of infections with pandrug-resistant bacteria. However, a large proportion of patients may be colonised by such MDR bacteria without any sign of infection, leading to a recurrent question for clinicians as to whether antibiotic treatment should be given and will be effective in the presence of resistance mechanisms. The worldwide emergence of A. baumannii strains resistant to colistin is worrying and the increasing use of colistin to treat infections caused by MDR bacteria will inevitably increase the recovery rate of colistin-resistant isolates in the future. Current knowledge about A. baumannii, including biological and epidemiological aspects as well as resistance to antibiotics and antibiotic therapy, are reviewed in this article, in addition to therapeutic recommendations.

In vitro activity of tigecycline and comparators against Gram-negative pathogens isolated from blood in Europe (2004–2009)

Arjana Tambic Andrasevic, Michael J. Dowzicky — 2011-12-21

Abstract: Here we report on the antimicrobial resistance amongst Gram-negative isolates (excluding Acinetobacter spp.) collected from blood culture sources at European study sites as part of the global Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) from the study start in 2004 until August 2009. All isolates were collected and tested for minimum inhibitory concentrations using Clinical and Laboratory Standards Institute methodology. Over the collection period, extended-spectrum β-lactamase (ESBL) production was recorded in 21.1% of Klebsiella pneumoniae, 2.6% of Klebsiella oxytoca and 11.3% of Escherichia coli, primarily in Croatia, Greece, Hungary, Italy, Poland, Romania and the Slovak Republic. ESBL rates stabilised amongst K. pneumoniae over 2006–2009, but doubled amongst E. coli in 2008–2009. The patterns of antimicrobial resistance changed accordingly for both organisms. Generally, Greece had the highest antimicrobial resistance for K. pneumoniae, Italy for E. coli, Serratia marcescens and Enterobacter spp., and Croatia for Pseudomonas aeruginosa. High resistance rates amongst K. pneumoniae were also seen in Croatia and Italy. Imipenem resistance amongst K. pneumoniae was reported exclusively in Greece (13.8%); amongst other Enterobacteriaceae, imipenem resistance was absent or low. Similarly, meropenem resistance was low amongst the Enterobacteriaceae except K. pneumoniae from Greece (42.6%). Across Europe, the most active antimicrobial agents against the Enterobacteriaceae were tigecycline, amikacin and the carbapenems, each with <10% resistance each year. Against the other antimicrobials, significant increases in non-susceptibility were reported for K. pneumoniae and E. coli, both important causative pathogens of bacteraemia.

An antibacterial from Hypericum acmosepalum inhibits ATP-dependent MurE ligase from Mycobacterium tuberculosis

2011-11-14

Abstract: In a project to characterise new antibacterial chemotypes from plants, hyperenone A and hypercalin B were isolated from the hexane and chloroform extracts of the aerial parts of Hypericum acmosepalum. The structures of both compounds were characterised by extensive one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and were confirmed by mass spectrometry. Hyperenone A and hypercalin B exhibited antibacterial activity against multidrug-resistant strains of Staphylococcus aureus, with minimum inhibition concentration ranges of 2–128mg/L and 0.5–128mg/L, respectively. Hyperenone A also showed growth-inhibitory activity against Mycobacterium tuberculosis H37Rv and Mycobacterium bovis BCG at 75mg/L and 100mg/L. Neither hyperenone A nor hypercalin B inhibited the growth of Escherichia coli and both were non-toxic to cultured mammalian macrophage cells. Both compounds were tested for their ability to inhibit the ATP-dependent MurE ligase of M. tuberculosis, a crucial enzyme in the cytoplasmic steps of peptidoglycan biosynthesis. Hyperenone A inhibited MurE selectively, whereas hypercalin B did not have any effect on enzyme activity.

Efficacy and safety of moxifloxacin as antibacterial prophylaxis for patients receiving autologous haematopoietic stem cell transplantation: a randomised trial

2011-12-14

Abstract: Patients receiving high-dose chemotherapy with autologous peripheral blood stem cell transplantation (PBSCT) are at high risk of infections, especially bacteraemia. A prospective, double-blind, randomised, placebo-controlled, single-centre, pilot study was performed on oral moxifloxacin 400mg versus placebo for preventing bacteraemia in PBSCT recipients. Patients received moxifloxacin or placebo for the duration of neutropenia or until emergence of fever or other infections necessitating intravenous antibiotic treatment. Of 68 patients included in the trial, 2 were excluded from the trial before taking their first dose. The remaining 66 patients were eligible for evaluation in the intention-to-treat analysis set. Neutropenia with an absolute neutrophil count of <500cells/μL developed in 30 moxifloxacin-treated patients (88.2%) and 21 patients in the placebo group (65.6%) (P<0.03). Nine patients (26.5%) and eight patients (25.0%), respectively, were prematurely discontinued from study treatment. Breakthrough bacteraemia occurred in 3 moxifloxacin-treated patients (8.8%) and 9 patients in the placebo group (28.1%) (P=0.042). The time period until fever was 9.5 days [95% confidence interval (CI) 8.06–10.94 days) and 7.69 days (95% CI 6.51–8.85 days), respectively (P=0.0499). There was no difference in adverse events or toxicities between the groups. Moxifloxacin prevented bacteraemia and shortened febrile episodes in patients receiving autologous PBSCT. No significant increase of adverse events in the moxifloxacin arm was observed, possibly due to the rather small sample size.

Effect of antibiotic prescribing in primary care on meticillin-resistant Staphylococcus aureus carriage in community-resident adults: a controlled observational study

2011-11-14

Abstract: The objectives of this study were to investigate the relationship between primary care antibiotics prescribed within 2 months and 12 months and the carriage of meticillin-resistant Staphylococcus aureus (MRSA) in nasal flora from a large representative sample of community-resident adults. S. aureus isolates were obtained from nasal samples submitted by UK resident adults aged ≥16 years registered with 12 general practices in the former Avon and Gloucestershire health authority areas. Individual-level antibiotic exposure data during the 12 months prior to providing the samples were collected from the primary care electronic records. MRSA status was determined by measuring resistance to cefoxitin. In total, 6937 adults were invited to take part, of whom 5917 returned a nasal sample. S. aureus was identified in 946 samples and a total of 761 participants consented to primary care record review and had complete data for the analyses. There was no evidence of an association between any antibiotic in the previous 2 months and MRSA isolation, with an adjusted odds ratio (aOR) of 1.33 [95% confidence interval (CI) 0.12–15; P=0.8]. There was a suggestion of an association between any antibiotic use in the previous 12 months and MRSA, with an aOR of 2.45 (95% CI 0.95–6.3; P=0.06). In conclusion, there is a suggestion that antibiotics prescribed within 12 months is associated with the carriage of MRSA, but not within 2 months, although the 2-month analysis had fewer data subjects and was therefore underpowered to detect this association. A larger study would be able to clarify these associations further.

Colistin therapy in critically ill patients with chronic renal failure and its effect on development of renal dysfunction

Melda Turkoglu, Murat Dizbay, Arzu Çiftçi, F. Nur Aksakal, Gülbin Aygencel — 2011-11-24

Abstract: Recently, colistin has become a salvage therapy in the treatment of serious Intensive Care Unit infections owing to the emergence of extensively drug-resistant (XDR) bacterial isolates. This study aimed to show the effectiveness of colistin in critically ill patients with renal failure. A prospective case–control study of 94 patients admitted to medical intensive care units of a university hospital from December 2008 to June 2010 was conducted. All patients had infections with XDR Acinetobacter baumannii or Pseudomonas aeruginosa and received colistin. Cases comprised 39 patients with chronic renal failure (CRF) and controls were other patients without CRF. Apart from the male dominancy in the CRF group, there was no statistical difference between the two groups regarding demographic characteristics, Acute Physiology and Chronic Health Evaluation (APACHE) II score, and site and type of infection. In patients who completed colistin therapy, bacteriological cure was seen in 87% of patients with CRF and 95% of patients without CRF (P=0.890). Mortality in patients with CRF was similar to that in patients without CRF (44% and 42%, respectively) (P=0.999). Nephrotoxicity developed in 23.6% of patients in the control group. Concomitant nephrotoxic agents and total defined daily dose of colistin did not affect the development of nephrotoxicity. The mortality rate was 38% in patients with nephrotoxicity, similar to the mortality rate in patients without nephrotoxicity (36%) (P=0.999). In conclusion, in critically ill patients with CRF, colistin therapy, although used at a reduced dosage, was as effective as in patients without CRF.

In vitro antibacterial and antimalarial activity of dehydrophenylalanine-containing undecapeptides alone and in combination with drugs

2011-11-28

Abstract: A set of three cationic undecapeptides, analogous to the previously reported peptide VS2 (KWΔFWKΔFVKΔFVK), was created by alanine substitution in order to probe the effect of hydrophobicity on peptide activity. The activities of these peptides were determined against Escherichia coli, Staphylococcus aureus and the malaria parasite Plasmodium falciparum. VA1, the closest analogue of VS2, showed five-fold augmented activity [minimum inhibitory concentration (MIC)=10μM] against the Gram-positive bacterium S. aureus. The designed analogues were non-haemolytic and non-cytotoxic at their MICs and clinically relevant concentrations. By alanine substitution, it was also possible to probe the critical role of tryptophan residues in determining peptide potency. Circular dichroism studies of the peptides in a membrane-mimetic system showed a correlation between peptide helicity and antimicrobial activity. The peptides were also tested in combination with sublethal concentrations of antibiotic drugs (rifampicin and kanamycin) and the antimalarial drug chloroquine. In combination with these drugs, the effect of the peptides was synergistic or additive. These results provide insight into basic design principles for generating new clinically relevant lead peptides. It also provides an alternative strategy where a peptide and a non-peptide drug can be used in combination to battle increasingly drug-resistant microbes.

Continuous infusion of piperacillin/tazobactam in ventilator-associated pneumonia: a pilot study on efficacy and costs

2011-12-12

Abstract: Ventilator-associated pneumonia (VAP) occurs in nearly one-third of mechanically ventilated patients in the Intensive Care Unit. Piperacillin/tazobactam (TZP) is currently recommended in the empirical treatment of VAP, but intermittent dosing may result in inadequate serum concentrations. The efficacy and costs of continuous infusion (CI) of TZP, using therapeutic drug monitoring for real-time dose adjustment, was assessed in a prospective pilot study of 16 patients with VAP. TZP was given as a loading dose of 2.0/0.25g followed by a CI of 10.0/1.25g daily. Rapid antimicrobial susceptibility testing was used to determine the minimum inhibitory concentration (MIC) of the pathogens. TZP concentrations were determined by high-pressure liquid chromatography before and at 1, 6, 12, 24, 48, 72 and 96h after the onset of administration. Dosages were adjusted to maintain piperacillin concentrations four-fold above the MIC (T>4×MIC) of the pathogen, with a maximum dose of 16.0/2.0g. The cost of the total TZP administered was compared with the cost of a standard TZP regimen (16.0/2.0g) if given over the same period of time. The median MIC for TZP was 1μg/mL (range 0.025–32μg/mL). TZP concentrations were adequate for 71% of pathogens on the first day of therapy. Clinical cure was achieved in 9/10 patients who had adequate drug concentrations and in 3/6 patients with insufficient levels. The daily dose of TZP received by CI was 37.5% less than that of a standard regimen, which corresponds to a saving of €15 on daily therapy costs compared with the standard regimen. In conclusion, CI of TZP achieved optimal drug concentrations in most patients with VAP, with a favourable impact on costs. Adequate drug concentrations were achieved for MIC≤4μg/mL, but higher dosages should be considered for the treatment of pathogens with low susceptibility thresholds.

Activity of oritavancin and comparators in vitro against standard and high inocula of Staphylococcus aureus

Francis F. Arhin, Ingrid Sarmiento, Thomas R. Parr, Gregory Moeck — 2011-11-09

Abstract: In this study, the impact of inoculum density on the growth inhibitory and killing activities of oritavancin and comparators (vancomycin, daptomycin and linezolid) in vitro against four Staphylococcus aureus strains at clinically relevant drug concentrations was studied. Broth microdilution and time–kill assays were performed using a standard inoculum [ca. 105colony-forming units (CFU)/mL as per Clinical and Laboratory Standards Institute (CLSI) guidelines] and a high inoculum (ca. 107CFU/mL). Whereas minimal inhibitory concentrations (MICs) of comparators were 2–8-fold higher when tested at high inoculum, oritavancin MICs were 16-fold higher for all strains at the high inoculum relative to the standard inoculum. However, in time–kill assays, when tested at its fCmin [trough concentration of free (non-protein-bound) drug] and fCmax (peak concentration of non-protein-bound drug), oritavancin retained its bactericidal activity against a vancomycin-susceptible, meticillin-susceptible S. aureus (VS-MSSA) strain and a vancomycin-susceptible, meticillin-resistant S. aureus (VS-MRSA) strain both at standard and high inocula. At its fCmax, oritavancin was bactericidal at standard inoculum but not at high inoculum against two vancomycin-intermediate S. aureus (VISA) strains. Against both VISA strains at standard inoculum, oritavancin at its fCmin reduced cell density by between 2 and 3log (bacteriostatic), predicting that it will retain activity against certain VISA infections. However, oritavancin had no substantial growth inhibitory effect against either VISA strain at high inoculum, suggesting that in rare VISA infections with an anticipated high bacterial burden such as endocarditis, alternative oritavancin dosing strategies, including combinations with other agents, may be explored.

In vitro pharmacodynamic evaluation of garenoxacin against quinolone-resistant Streptococcus pneumoniae

Yoshiko Fukuda, Masahiro Takahata, Yoko Sugiura, Yuko Shinmura, Nobuhiko Nomura — 2011-11-17

Abstract: The bactericidal activity and resistance selectivity of garenoxacin against Streptococcus pneumoniae with mutations in ParC (S79F) or both GyrA (S81F) and ParC (D83Y and K137N) were investigated using in vitro pharmacokinetic models simulating plasma concentrations for a standard clinical regimen [400mg once daily (q.d.)]. The efficacy of garenoxacin was compared with that of levofloxacin (500mg q.d.) and moxifloxacin (400mg q.d.). Garenoxacin showed excellent bactericidal activity against S. pneumoniae, including quinolone-resistant S. pneumoniae (QRSP), achieving ratios of area under the plasma concentration–time curve over 24h to minimum inhibitory concentration (AUC0–24/MIC) ≥26.3, without emerging resistant subpopulations. The area above the killing curves was greater and the time to achieve 99.9% killing was shorter for garenoxacin than the corresponding values for levofloxacin and moxifloxacin. No resistant subpopulations and no additional substitution of amino acids in GyrA or ParC emerged following treatment with garenoxacin. On the other hand, in the parC mutant strain, levofloxacin and moxifloxacin treatment caused an increase in the frequency of the resistant population and an additional substitution of amino acids in GyrA (levofloxacin, S81Y/F/C; moxifloxacin, S81Y or E85K). In QRSP with mutations in GyrA and ParC, levofloxacin had no bactericidal activity, whilst the bactericidal activity of moxifloxacin was less than that of garenoxacin; moreover, an additional substitution of amino acids in ParC (S79Y) was noted. In conclusion, garenoxacin corresponding to an oral dose of 400mg showed excellent bactericidal activity against S. pneumoniae, including QRSP, without the emergence of resistant mutants.

Rapid emergence and spread of OXA-48-producing carbapenem-resistant Enterobacteriaceae isolates in Belgian hospitals

2011-11-24

Abstract: During a polymerase chain reaction (PCR)-based surveillance study of β-lactam resistance, 19 OXA-48-positive enterobacterial isolates were detected at nine Belgian hospitals from January 2010 to April 2011. Most cases were presumed to have been locally acquired and were detected in patients who had not travelled abroad. Clonally related outbreaks occurred in two different cities. The majority of isolates co-produced several β-lactamases as well as non-β-lactam resistance genes. This report highlights the rapid emergence and spread of OXA-48-producing Enterobacteriaceae in Belgium.

Drug susceptibility testing and pharmacokinetics question current treatment regimens in Mycobacterium simiae complex disease

2011-11-18

Abstract: The Mycobacterium simiae complex bacteria can cause opportunistic infections in humans. In the case of definite disease, there are no evidence-based treatment regimens and outcomes are very disappointing. To increase the evidence base underpinning treatment regimens for M. simiae complex disease, drug susceptibility patterns and rifampicin/ethambutol synergy were assessed retrospectively in 69 clinical M. simiae complex isolates from 60 patients (22 patients with M. simiae, 24 with Mycobacterium lentiflavum, 8 with Mycobacterium triplex, 5 with Mycobacterium parascrofulaceum and 1 with Mycobacterium stomatepiae) submitted to the mycobacteriology laboratory at National Jewish Health (Denver, CO). Quantitative drug susceptibility testing (DST) was performed using the radiometric BacTec 460 macrodilution method. Results were related to pharmacokinetic (PK) measurements, where available. All M. simiae complex species proved susceptible to clarithromycin and, to a lesser extent, rifabutin, clofazimine, streptomycin and moxifloxacin. Synergy or additive action between rifampicin and ethambutol was observed for all species except M. simiae. Mycobacterium simiae is poorly susceptible in vitro to rifampicin and ethambutol alone as well as in combination; PK measurements support the limited efficacy of these drugs against M. simiae. The triple-drug regimen of a rifamycin, ethambutol and a macrolide may be advised to treat disease caused by M. lentiflavum, M. triplex, M. parascrofulaceum and M. stomatepiae; for M. simiae, this regimen appears less active. These findings may partly explain the limited treatment results in M. simiae disease. A treatment regimen including a macrolide, moxifloxacin and one or two additional drugs based on DST results may be advisable; clofazimine and amikacin or streptomycin are potential candidates.

Use of anti-infective drugs during pregnancy and the risk of preterm birth

Fabiano Santos, Odile Sheehy, Sylvie Perreault, Ema Ferreira, Anick Bérard — 2011-11-14

Anti-infective drugs are amongst the most frequently used medications during pregnancy . Maternal infections during gestation are associated with an increased risk of preterm birth . Preterm babies are at risk of mortality and long-term morbidity . Hence, given its impacts on the health of the mother and foetus, prompt antibiotic treatment when an infection occurs during gestation is warranted . However, there is some controversy on the use of anti-infective drugs to prevent preterm birth . Indeed, studies have failed to show convincingly the independent effect of anti-infective drugs used to treat maternal infections on the risk of prematurity.

Diversity of acquired β-lactamases amongst Klebsiella pneumoniae in Greek hospitals

2011-11-21

Until 2001, the majority of multidrug-resistant Klebsiella pneumoniae isolated in Greek hospitals produced extended-spectrum β-lactamases (ESBLs), with SHV-5 being the most prevalent type, followed by CTX-M and GES type enzymes . During the period 2002–2007, K. pneumoniae producing the metallo-β-lactamase (MBL) VIM-1 were isolated at increasing frequencies . In late 2007, the first K. pneumoniae producing KPC-2 β-lactamase was isolated and until the end of 2008 producers of the latter carbapenemase became predominant in the major hospitals throughout the country . Thus, findings during the last decade show a continuously evolving situation requiring regular monitoring. In this study, the prevalence of clinically important β-lactamases was determined in a recent representative sample of K. pneumoniae isolates derived from Greek hospitals.

Synergistic activity of sulbactam combined with colistin against colistin-resistant Acinetobacter baumannii

2011-11-21

Acinetobacter baumannii is an emerging multidrug-resistant (MDR) pathogen that is responsible for community- and hospital-acquired infections that are difficult to control and treat . With increasing antimicrobial resistance to carbapenems, colistin is often the treatment of last resort, however colistin-resistant clinical isolates have already been reported. Since therapeutic options are very limited or absent in some cases of infection with pandrug-resistant bacteria, there is an urgent need to find new antibiotic strategies. In this study, we report the in vitro synergistic activity of a combination of colistin with sulbactam against colistin-resistant A. baumannii strains.

Community-onset bacteraemia caused by fluoroquinolone-resistant Klebsiella pneumoniae: clinical epidemiology and risk factors

2011-11-21

Despite the high prevalence of antimicrobial-resistant Klebsiella pneumoniae in hospital-acquired infections, the clinical epidemiology of fluoroquinolone (FQ) resistance in community-onset K. pneumoniae bacteraemia is not well understood. This study was performed to evaluate the clinical features and risk factors for community-onset FQ-resistant K. pneumoniae bacteraemia amongst patients admitted to the Emergency Department.

Emergence of nosocomial New Delhi metallo-β-lactamase-1 (NDM-1)-producing Klebsiella pneumoniae in patients admitted to a tertiary care hospital in Kuwait

W. Jamal, V.O. Rotimi, M. John Albert, F. Khodakhast, E.E. Udo, L. Poirel — 2011-11-23

Resistance to carbapenems has recently emerged in Enterobacteriaceae and has resulted in serious clinical consequences as carbapenems are practically the last option to treat infections due to these bacteria. Recently, the New Delhi metallo-β-lactamase-1 (NDM-1) encoded by the blaNDM-1 gene has been identified from a Klebsiella pneumoniae isolate from a urine sample of a Swedish patient of Indian origin following hospitalisation in India . Members of the family Enterobacteriaceae producing this enzyme have been reported extensively in the UK, India and Pakistan and to a lesser extent in other parts of the world .

Occurrence and molecular epidemiology of blaCTX-M, including co-occurrence of blaTEM and blaSHV genes, and sul1 association in Indian Enterobacteriaceae

Anuradha Singh, Mohd Shahid, Farrukh Sobia, Umesh, Haris M. Khan — 2011-12-22

β-Lactam antibiotics are the first-line curative treatment for infections caused by Enterobacteriaceae, however increasing resistance to these compounds has been reported in the last decade . Resistance to β-lactams is mediated by the production of extended-spectrum β-lactamases (ESBLs). CTX-M is the most common type of ESBL and has been reported in Enterobacteriaceae isolates from various countries including Poland, Canada, France, the UK, Russia, Cameroon, Japan and Bulgaria as well as in India .

Corrigendum to “Linezolid resistance in Staphylococcus epidermidis associated with a G2603T mutation in the 23S rRNA gene” [Int. J. Antimicrob. Agents 34 (2009) 281–282]

Nilton Lincopan, Lara M. de Almeida, Maria R. Elmor de Araújo, Elsa M. Mamizuka — 2011-12-07

The authors regret the error which appeared in the above article and would like to publish the following corrigendum: “We reported the G2306T mutation in the 23S rRNA gene of the S. epidermidis strain BF734/08 by relating it to the number of the S. epidermidis strain CP000029 (GenBank accession number) instead of correlating it to the standard E. coli numbering system. Thus, the mutation G2306T is, actually, the same mutation that had been described as G2576T according to the E. coli number. We acknowledge Dr. Shaw for her contributions to this correction.”