Sir, Methicillin-resistant Staphylococcus aureus (MRSA) is of growing concern in public and animal health and it is important to ensure efficient and reliable methods for MRSA identification. Standard confirmatory tests include PCR for detection of the mecA gene and protein agglutination for identification of the penicillin-binding protein 2a (PBP2a). In 2011, a novel mecA homologue designated mecC (or mecALGA251) was described in S. aureus. This MRSA variant will not be detected with the usual mecA PCR approaches or with the PBP2a agglutination tests, representing a challenge to MRSA confirmation in diagnostic laboratories. Searching for mecC has recently been performed in several countries. Investigated isolates have either been part of historical collections or originated from current diagnostic submissions. The chosen candidates for mecC screening have typically been isolates with a phenotype corresponding to MRSA but lacking mecA, and/or isolates belonging to clonal lineages already associated with mecC carriage. So far the occurrence of the mecC gene has been confirmed in isolates from the typical hosts, humans and/or cattle, in several countries in Northern Europe: the UK, Denmark, Ireland, Germany, France, Sweden and Norway. – 8 Only two studies examining isolates from hosts other than humans and cattle are known; one of these studies investigated a historical isolate collection and mecC was found in S. aureus from a dog, a seal and a chaffinch (all from the UK), from a rabbit and rats from Belgium, and from sheep in Denmark. The other study, recently published by Walther et al., found mecC-positive MRSA from two dogs, seven cats and a guinea pig. The MRSA isolates investigated originated from samples submitted to a laboratory in Germany during the period 2008–11. Based on current knowledge, mecC seems to have a rather wide geographical and host distribution, but occurs at low frequencies. The Norwegian Veterinary Institute has recently detected mecC in an MRSA isolate from a submission to our diagnostic bacteriological service unit in Bergen. The isolate originated from a cat and represents the first finding from current diagnostic activity performed on samples from companion animals. The mecC-positive MRSA (designated 2012-50-2037) was isolated from an eye swab from a 5-year-old house cat with chronic conjunctivitis and stomatitis. The cat had tested negative for all relevant viruses and Chlamydophila felis. Initial treatment with systemic clavulanate-potentiated amoxicillinand topical fusidicacid was ineffective, but improvement was seen after a change of treatment to systemic enrofloxacin and topical dexamethasone, neomycin and polymyxin B. The cat is currently living in a household with two adults, two children and another cat. The MRSA carrier status of the family members and the other cat is not known. The isolate was routinely tested for susceptibility to antimicrobial agents following the disc diffusion method and breakpoints described by EUCAST (www.eucast.org, 7 November 2012, date last accessed). The isolate showed resistance to b-lactams only. MICs were subsequently determined by the use of a broth dilution method (Trek Diagnostics). The following antimicrobial agents were tested: penicillin, cefoxitin, ciprofloxacin, erythromycin, clindamycin, gentamicin, tetracycline, linezolid, fusidic acid, rifampicin, chloramphenicol, trimethoprim, vancomycin, quinupristin/dalfopristin and mupirocin. The isolate exhibited resistance to the b-lactams only, with a cefoxitin MIC of 16 mg/L. The MIC of oxacillin was 2 mg/L, determined by Etest (bioMérieux). The results were interpreted according to EUCAST. S. aureus ATCC 29213 was included as quality control. DNAwas prepared by the boil lysis method and subsequentlysubjected to PCR for detection of mecA, mecC, nuc and 16S rDNA with primers previously described. In addition to a negative control, positive control strains included S. aureus CCUG 29213 (nuc+), S. aureus CCUG 35603 (nuc+, mecA+), Staphylococcus pseudintermedius CCUG 49543 (nuc, mecA) and S. aureus SVA-AB-773 (nuc+, mecC+). The PCR results confirmed MRSA with mecC. The sequence of the mecC amplicon was determined and showed 100% identity with the previously determined mecC sequence. The mecC gene was probably located on a type XI SCCmec element as PCRs with primers for the mecI, mecR, ccrA, ccrB and blaZ genes related to SCCmecXI produced amplicons of correct sizes. The spa typing showed that the isolate belonged to spa type t6902. This spa type has only one other recording in the Ridom spaserver (http://spaserver.ridom.de/, 7 November 2012, date

BACKGROUND Surveillance of HIV-1 drug resistance in treated patients with plasma viral load (VL) >50 copies/mL. METHODS The protease and reverse transcriptase (RT) genes were systematically sequenced in samples from 756 patients with VL >50 copies/mL in 2009. The genotyping results were interpreted for each antiretroviral drug (ARV) by using the ANRS algorithm v21. Weighted analyses were used to derive representative estimates of percentages of patients. Prevalence rates were compared with those obtained in 2004 among patients with VL >1000 copies/mL. RESULTS Sequences were obtained for 506 patients. Sequencing was successful in 45%, 80% and 96% of samples with VL of 51-500, 501-1000 and >1000 copies/mL, respectively. Resistance or possible resistance to at least one ARV was observed in 59% of samples. Overall, 0.9% of samples contained viruses resistant to all drugs belonging to at least three drug classes. All resistance prevalence rates were significantly lower in 2009 than in 2004. CONCLUSION In France, where 86% of patients were receiving combination antiretroviral therapy in 2009, only 15.0% of patients had a VL >50 copies/mL, suggesting that only 8.9% of treated patients could potentially transmit resistant viruses. Only 0.08% of patients harboured viruses fully resistant to at least three antiretroviral drug classes. Further studies are needed to determine whether resistance continues to decline over time.

Background: We developed clinically relevant genotypic scores for resistance to fosamprenavir/ritonavir in HIV-1 protease inhibitor (PI)-experienced patients.Methods: PI-experienced patients with virological failure receiving fosamprenavir/ritonavir as the sole PI for at least 3 months and with detectable fosamprenavir plasma levels were included. The impact of baseline protease mutations on virological response (VR, i.e. decrease in plasma HIV-1 RNA between baseline and month 3) was analysed using the Mann-Whitney test. Mutations with prevalence > 10% and P value < 0.10 were retained. The Jonckheere-Terpstra test was used to select the combination of mutations most strongly associated with VR. The association between score and VR was assessed by multivariate backward regression.Results: In the 73 patients included, the median baseline HIV-1 RNA was 4.6 log(10) copies/mL (range: 2.7-6.9) and the mean decrease at month 3 was -1.07 +/- 1.40 log(10) copies/mL. Ninety per cent of the patients were infected by HIV-1 subtype B variants. Two fosamprenavir/ritonavir mutation scores were constructed: score A (L10F/I/V + L33F + M36I + I54L/M/V/A/T/S + I62V + V82A/F/C/G + I84V + L90M) was based only on mutations associated with a worse VR, whereas score B (L10FIV + L33F + M36I + I54L/M/V/A/T/S + A71V - V77I - N88S + L90M) also took into account favourable mutations. Both scores were independent predictors of VR, however, co-administration of tenofovir was associated with a worse VR and the presence of the N88S protease mutation and co-administration of enfuvirtide with a better VR.Conclusions: These clinically validated mutation scores should be of interest for the clinical management of PI-experienced patients. The fosamprenavir/ritonavir score A was introduced in the 2006 ANRS algorithm along with isolated mutations I50V and V32I + I47V.

The performance of French virology laboratories belonging to the ANRS network has been assessed annually for 3 years. The performance of these laboratories was compared between the years 2002 and 2003. Ten and 7 coded samples were sent to 38 virology laboratories in 2002 and 45 virology laboratories in 2003, respectively. Each panel of coded samples included at least one HIV-negative control, a pair of duplicate specimens, samples with a wide range of viral loads, and samples with a large number of resistance mutations. The laboratories used their standard sequencing procedures and were asked to report the amino acids at codons associated with resistance mutations, based on the IAS-USA expert panel list. The reference amino acid sequences were defined as those most frequently reported by the participants. The specificity of detection of RT mutations was significantly better in 2003 (99.9%) than in 2002 (99.7%) (P=0.05). There was no difference between 2002 and 2003 in the specificity of detection of protease mutations (99.6% and 99.8%) or the sensitivity of detection of RT mutations (98.8% and 98.2%). The sensitivity of detection of protease mutations improved significantly between 2002 and 2003 (97.6% and 99.0%, respectively; P=0.037). The proportion of laboratories reporting fully accurate results, in terms of amplification, specificity, sensitivity, and reproducibility, tended to increase between 2002 and 2003 (P=0.077). No errors were made by 19% of laboratories in 2002, compared to 42% in 2003. These results show the value of repeated external quality assessments.

Despite satisfactory efficacy of WHO-recommended second-line antiretroviral treatment for patients with HIV in low-income countries, the need for simplified, low-cost, and less-toxic maintenance strategies remains high. We compared boosted protease inhibitor monotherapy with dual therapy with boosted protease inhibitor plus lamivudine in patients on second-line antiretrovial therapy (ART).We did a multicentre, randomised, parallel, open-label, superiority, trial in the HIV services of five hospitals in sub-Saharan Africa (Yaoundé, Cameroon; Dakar, Senegal; and Bobo Dioulasso, Burkina Faso). We recruited patients from the long-term, post-trial cohort of the ANRS 12169/2LADY study that compared the efficacy of three second-line combinations based on boosted protease inhibitors. Participants for our study were HIV-1 infected with multiple mutations including M184V, at first-line failure, aged 18 years and older, on boosted protease inhibitor plus two nucleoside reverse transcriptase inhibitors (NRTI) for at least 48 weeks with at least 48 weeks follow-up in the 2LADY trial, with two viral load measurements of less than 200 copies per mL in the previous 6 months, CD4 counts of more than 100 cells per μL, adherence of at least 90%, and no change to ART in the past 3 months. We randomly assigned participants (1:1) to receive either monotherapy with their boosted protease inhibitor (once-daily darunavir 800 mg [two 400 mg tablets] boosted with ritonavir 100 mg [one tablet] or coformulation of lopinavir 200 mg with ritonavir 50 mg [two tablets taken twice per day]) or to boosted protease inhibitor plus once-daily lamivudine 300 mg (one 300 mg tablet or two 150 mg tablets). Computer-generated randomisation was stratified by study site and viral load at screening (< 50 copies per mL, and 50–200 copies per mL), and concealed from study personnel throughout the inclusion period. After randomisation, treatment allocation was not masked from clinicians or patients]. Patients had follow-up visits at weeks 4 and 12, and every 3 months until 96 weeks; if viral load exceeded 500 copies per mL at any visit, NRTI (tenofovir and lamivudine) were reintroduced into treatment. The primary outcome was the proportion of participants who had treatment failure at 96 weeks in the intention-to-treat analysis, where treatment failure was defined as one of the following: a confirmed viral load of more than 500 copies per mL, reintroduction of NRTI, or interruption of boosted protease inhibitor. We designed the study to detect a difference of 12% between groups in the primary outcome, with an expected 20% of patients having treatment failure in the monotherapy group. This study is registered with ClinicalTrials.gov, number NCT01905059.Between March 5, 2014, and Jan 26, 2015, 265 participants were assigned to receive monotherapy (133) or boosted protease inhibitor plus lamivudine (132). At week 48, an independent data safety monitoring board reviewed data, and advised discontinuation of the monotherapy group because the number of failures had exceeded the expected 20%; therefore results here are for week 48. At this point, treatment failure occurred in four (3·0%; 95% CI 0·8–7·6) of 132 participants on dual therapy and 33 (24·8%; 17·7–33·0) of 133 participants on monotherapy (relative risk 8·2, 95% CI 3·0–22·5; odds ratio 10·6, 95% CI 3·6–42·1). The difference between groups (21·8%, 95% CI 13·9–29·7; p<0·0001) showed superiority of dual therapy compared with monotherapy. We recorded 46 severe adverse events of grade 3 or 4 (29 in the monotherapy group, 17 in the boosted protease inhibitor plus lamivudine group); one event in the montherapy group (intoxication resulting from co-administration of ritonavir-boosted lopinavir with an ergotamine derivate) was deemed related to study drug. Two participants in the monotherapy group and one in the dual therapy group died, all from causes not related to study drugs or procedures (one from complications from gastric cancer surgery, one in a work accident, and one from a lung disease of unknown cause).After viral suppression with boosted protease inhibitor plus NRTI in second-line ART, maintenance therapy with boosted protease inhibitor plus lamivudine was associated with a high rate of success, despite the presence of M184V mutations at first-line treatment failure. Results indicated that boosted protease inhibitor monotherapy cannot be recommended for these patients.Agence National de Recherche sur le Sida et les hépatites and Janssen Pharmaceutica.

ABSTRACT The genotypic inhibitory quotient (GIQ) has been proposed as a way to integrate drug exposure and genotypic resistance to protease inhibitors and can be useful to enhance the predictivity of virologic response for boosted protease inhibitors. The aim of this study was to evaluate the predictivity of the GIQ in 116 protease inhibitor-experienced patients treated with lopinavir-ritonavir. The overall decrease in human immunodeficiency virus type 1 (HIV-1) RNA from baseline to month 6 was a median of −1.50 log10 copies/ml and 40% of patients had plasma HIV-1 RNA below 400 copies/ml at month 6. The overall median lopinavir study-state Cmin concentration was 5,856 ng/ml. Using univariate linear regression analyses, both lopinavir GIQ and the number of baseline lopinavir mutations were highly associated with virologic response through 6 months. In the multivariate analysis, only lopinavir GIQ, baseline HIV RNA, and the number of prior protease inhibitors were significantly associated with response. When the analysis was limited to patients with more highly mutant viruses (three or more lopinavir mutations), only lopinavir GIQ remained significantly associated with virologic response. This study suggests that GIQ could be a better predictor of the virologic response than virological (genotype) or pharmacological (minimal plasma concentration) approaches used separately, especially among patients with at least three protease inhibitor resistance mutations. Therapeutic drug monitoring for patients treated by lopinavir-ritonavir would likely be most useful in patients with substantially resistant viruses.

OBJECTIVE:To survey the frequency of genotypic antiretroviral resistance and the spread of non-B subtypes in patients with primary HIV-1 infection (2001-2002) and in treatment-naive chronically HIV-1-infected patients (2001).METHODS:Plasma samples from 303 patients with acute HIV-1 infection (Primo study) and 363 treatment-naive patients with chronic HIV-1 infection (Odyssee study) were tested for genotypic resistance. Resistance mutations were identified from the International AIDS Society Resistance Testing-USA panel and resistant viruses were defined according to the French Agence Nationale de Recherches sur le SIDA (ANRS) resistance algorithm.RESULTS:In the Primo study, 14% of the patients had viruses with resistance mutations and 12% of patients had viruses with mutations conferring resistance to least 1 antiretroviral drug. Thirty patients had viruses with mutations to at least 1 antiretroviral drug in a single pharmacologic class. Six patients were infected by viruses resistant to 2 or 3 classes of drugs. In the Odyssee study, the prevalence of reverse transcript (RT) associated and major protease inhibitor-associated mutations was 6.1% (95% CI: 3.6-8.6). Six patients had viruses resistant to at least 1 antiretroviral drug and 3 patients had viruses resistant to 2 classes of antiretroviral drugs. Twenty-four percent of acutely infected patients harbored non-B subtype strains (19% in 1999-2000) and 33.2% of chronically infected patients (10% in 1998; P < 0.0001).CONCLUSION:In France, the frequency of HIV-1 resistance in untreated patients was not significantly higher in 2001-2002 than in previous surveys while the prevalence of non-B subtypes is increasing.

Auteur(s) : J-C Plantier1, V Lemee1, I Dorval2, M Gueudin1, J Braun1, P Hutin2, A Ruffault3, A Curie1, F Simon1 1Unite de virologie, laboratoire associe CNR du VIH, Hopital Charles-Nicolle, 76000 Rouen 2Centre Hospitalier de Cornouaille, Quimper-Concarneau 3Laboratoire de Virologie, CHU Pontchaillou, Rennes Le VIH1 est divise en trois groupes : M, N et O. Le groupe M est pandemique, tandis que le groupe O est limite a l’Ouest de l’Afrique centrale et aux pays lies historiquement [...]

Auteur(s) : J-C Plantier1, V Lemee1, I Dorval2, M Gueudin1, J Braun1, P Hutin2, A Ruffault3, A Curie1, F Simon1 1Unite de virologie, laboratoire associe CNR du VIH, Hopital Charles-Nicolle, 76000 Rouen 2Centre Hospitalier de Cornouaille, Quimper-Concarneau 3Laboratoire de Virologie, CHU Pontchaillou, Rennes Le VIH1 est divise en trois groupes : M, N et O. Le groupe M est pandemique, tandis que le groupe O est limite a l’Ouest de l’Afrique centrale et aux pays lies historiquement [...]