Tobacco, alcohol, cannabis, and illicit drug use and their association with CD4/CD8 cell count ratio in people with controlled HIV: a cross-sectional study (ANRS CO3 AQUIVIH-NA-QuAliV)

BACKGROUND

To evaluate drug use (alcohol, tobacco, cannabis and other drugs) and its association with mean CD4/CD8 T cell count ratio, a marker of chronic inflammation, in virally suppressed people living with HIV-1 (PLWH) in Nouvelle Aquitaine, France.

METHODS

A multi-centric, cross-sectional analysis was conducted in 2018-19 in the QuAliV study-ANRS CO3 AQUIVIH-NA cohort. Tobacco, alcohol, cannabis, and other drug use (poppers, cocaine, amphetamines, synthetic cathinones, GHB/GBL) were self-reported. CD4 and CD8 T cell counts and viral load measures, ± 2 years of self-report, and other characteristics were abstracted from medical records. Univariable and multivariable linear regression models, adjusted for age, sex, HIV risk group, time since HIV diagnosis, and other drug use were fit for each drug and most recent CD4/CD8 ratio.

RESULTS

660 PLWH, aged 54.7 ± 11.2, were included. 47.7% [315/660] had a CD4/CD8 ratio of < 1. Their mean CD4/CD8 ratio was 1.1 ± 0.6. 35% smoked; ~ 40% were considered to be hazardous drinkers or have alcohol use disorder; 19.9% used cannabis and 11.9% other drugs. Chemsex-associated drug users' CD4/CD8 ratio was on average 0.226 (95% confidence interval [95% CI] - 0.383, - 0.070) lower than that of non-users in univariable analysis (p = 0.005) and 0.165 lower [95% CI - 0.343, 0.012] in multivariable analysis (p = 0.068).

CONCLUSIONS

Mean differences in CD4/CD8 ratio were not significantly different in tobacco, alcohol and cannabis users compared to non-users. However, Chemsex-associated drug users may represent a population at risk of chronic inflammation, the specific determinants of which merit further investigation.

TRIAL REGISTRATION NUMBER

NCT03296202.

Severe bacterial non-AIDS infections in persons with HIV: the epidemiology and evolution of antibiotic resistance over an 18-year period (2000-2017) in the ANRS CO3 AquiVih-Nouvelle-Aquitaine cohort

BACKGROUND

Severe non-AIDS bacterial infections (SBIs) are one of the leading causes of hospital admissions among persons with HIV (PWH) in regions with high ART coverage.

METHODS

This large prospective cohort study of PWH examined the types of infections, bacterial documentation, and evolution of antibiotic resistance among PWH hospitalized with SBIs over an 18-year period.

RESULTS

Between 2000 and 2017, 459 PWH had at least one SBI with bacterial documentation. Among the 847 SBIs, there were 280 cases of bacteremia, 269 cases of pneumonia, and 240 urinary tract infections. The 1025 isolated bacteria included Enterobacteriaceae (n = 394; mainly Escherichia coli), Staphylococcus aureus (n = 153) and Streptococcus pneumoniae (n = 82). The proportion of S. pneumoniae as the causative agent in pneumonia and bacteremia decreased sharply over time, from 34% to 8% and from 21 to 3%, respectively.The overall antibiotic resistance of S. aureus and S. pneumoniae decreased progressively but it increased for Enterobacteriaceae (from 24% to 48% for amoxicillin-clavulanate, from 4 to 18% for cefotaxime, and from 5% to 27% for ciprofloxacin). Cotrimoxazole prophylaxis was associated with higher nonsusceptibility of S. pneumoniae to amoxicillin and erythromycin, higher nonsusceptibility of Enterobacteriaceae to beta-lactams and fluoroquinolones, and a higher risk of extended-spectrum β-lactamase producing Enterobacteriaceae.

CONCLUSIONS

The bacterial resistance pattern among PWH between 2014 and 2017 was broadly similar to that in the general population, with the exception of a higher resistance profile of Enterobacteriaceae to fluoroquinolones. The use of cotrimoxazole as prophylaxis was associated with an increased risk of antibiotic resistance.

HCV cure: an appropriate moment to reduce cannabis use in people living with HIV? (ANRS CO13 HEPAVIH data)

BACKGROUND

Thanks to direct-acting antivirals, hepatitis C virus (HCV) infection can be cured, with similar rates in HCV-infected and HIV-HCV co-infected patients. HCV cure is likely to foster behavioral changes in psychoactive substance use, which is highly prevalent in people living with HIV (PLWH). Cannabis is one substance that is very commonly used by PLWH, sometimes for therapeutic purposes. We aimed to identify correlates of cannabis use reduction following HCV cure in HIV-HCV co-infected cannabis users and to characterize persons who reduced their use.

METHODS

We used data collected on HCV-cured cannabis users in a cross-sectional survey nested in the ANRS CO13 HEPAVIH cohort of HIV-HCV co-infected patients, to perform logistic regression, with post-HCV cure cannabis reduction as the outcome, and socio-behavioral characteristics as potential correlates. We also characterized the study sample by comparing post-cure substance use behaviors between those who reduced their cannabis use and those who did not.

RESULTS

Among 140 HIV-infected cannabis users, 50 and 5 had reduced and increased their use, respectively, while 85 had not changed their use since HCV cure. Cannabis use reduction was significantly associated with tobacco use reduction, a decrease in fatigue level, paying more attention to one's dietary habits since HCV cure, and pre-HCV cure alcohol abstinence (p = 0.063 for alcohol use reduction).

CONCLUSIONS

Among PLWH using cannabis, post-HCV cure cannabis reduction was associated with tobacco use reduction, improved well-being, and adoption of healthy behaviors. The management of addictive behaviors should therefore be encouraged during HCV treatment.

Mechanically tunable, human mesenchymal stem cell viable poly(ethylene glycol)-oxime hydrogels with invariant precursor composition, concentration, and stoichiometry

Hydrogels are used widely for exploratory tissue engineering studies. However, currently no hydrogel systems have been reported that exhibit a wide range of elastic modulus without changing precursor concentration, identity, or stoichiometry. Herein, ester and amide-based PEG-oxime hydrogels with tunable moduli (~5-30 kPa) were synthesized with identical precursor mass fraction, stoichiometry, and concentration by varying the pH and buffer concentration of the gelation solution, exploiting the kinetics of oxime bond formation. The observed modulus range can be attributed to increasing amounts of network defects in slower forming gels, as confirmed by equilibrium swelling and small angle neutron scattering (SANS) experiments. Finally, hMSC viability was confirmed in these materials in a 24 h assay. While only an initial demonstration of the potential utility, the controlled variation in defect density and modulus is an important step forward in isolating system variables for hypothesis-driven biological investigations.

[Pharmacokinetic risk factors of beta-blockers overdose in the elderly: Case report and pharmacology approach]

Beta-blockers are widely prescribed in elderly patients and may induce severe adverse drug reactions. We report a case of bisoprolol-induced bradycardia in an elderly patient with impaired renal function and use of cytochrome P450 inhibitors. A literature review has been performed in order to analyze pharmacokinetic risk factors of beta-blockers overdosing in geriatrics. Various mechanisms can result in decreased elimination of beta-blockers. These mechanisms vary according to the beta-blocker agent and may be combined in some individuals, especially elderly patients. This can lead to unexpected overexposure. Knowledge about drug interactions and pharmacokinetic elimination pathways is important for preventing overexposure and adverse drug reactions when using beta-blockers.

The absence of hyperbilirubinaemia is highly predictive of treatment failure in advanced HIV-infected patients treated with indinavir

In order to determine prognostic factors associated with treatment failure (TF) in advanced HIV-infected patients treated with a regimen including indinavir, a prospective cohort study of 80 patients was set up between 1 March and 31 December 1996. TF time was calculated using the Kaplan–Meier method, from treatment induction to the first of the following events: treatment modification for adverse event or lack of significant virological and/or immunological response, AIDS-defining diagnosis or death. Date of point was 31 December 1998. Multivariate analysis was performed using a Cox model. At baseline, 60% of the patients were AIDS-free, median viral load and CD4+ count were respectively 4.8 log/ml and 79/μl. After a median follow-up of 26 months, 70% of the patients experienced a TF in a median time of 8 months. Seventy-two per cent presented an hyperbilirubinaemia (>2 mg/dl). In multivariate analysis, initial AIDS stage (hazard ratios [HR]=1.94, P=0.04) and digestive intolerance (HR=2.32, P=0.003) were predictive of TF. Conversely, hyperbilirubinaemia was associated with a better outcome (HR=0.35, P<0.0001). These 2 latter parameters very likely reflected patients' treatment compliance.

Laboratory intercomparison of gene expression assays

The possibility of a large-scale acute radiation exposure necessitates the development of new methods that could provide rapid individual dose estimates with high sample throughput. The focus of the study was an intercomparison of laboratories' dose-assessment performances using gene expression assays. Lithium-heparinized whole blood from one healthy donor was irradiated (240 kVp, 1 Gy/min) immediately after venipuncture at approximately 37°C using single X-ray doses. Blood samples to establish calibration curves (0.25-4 Gy) as well as 10 blinded test samples (0.1-6.4 Gy) were incubated for 24 h at 37°C supplemented with an equal volume of medium and 10% fetal calf serum. For quantitative reverse transcription polymerase chain reaction (qRT-PCR), samples were lysed, stored at -20°C and shipped on ice. For the Chemical Ligation Dependent Probe Amplification methodology (CLPA), aliquots were incubated in 2 ml CLPA reaction buffer (DxTerity), mixed and shipped at room temperature. Assays were run in each laboratory according to locally established protocols. The mean absolute difference (MAD) of estimated doses relative to the true doses (in Gy) was calculated. We also merged doses into binary categories reflecting aspects of clinical/diagnostic relevance and examined accuracy, sensitivity and specificity. The earliest reported time on dose estimates was <8 h. The standard deviation of technical replicate measurements in 75% of all measurements was below 11%. MAD values of 0.3-0.5 Gy and 0.8-1.3 Gy divided the laboratories contributions into two groups. These fourfold differences in accuracy could be primarily explained by unexpected variances of the housekeeping gene (P = 0.0008) and performance differences in processing of calibration and blinded test samples by half of the contributing laboratories. Reported gene expression dose estimates aggregated into binary categories in general showed an accuracies and sensitivities of 93-100% and 76-100% for the groups, with low MAD and high MAD, respectively. In conclusion, gene expression-based dose estimates were reported quickly, and for laboratories with MAD between 0.3-0.5 Gy binary dose categories of clinical significance could be discriminated with an accuracy and sensitivity comparable to established cytogenetic assays.

Comparison of established and emerging biodosimetry assays

Rapid biodosimetry tools are required to assist with triage in the case of a large-scale radiation incident. Here, we aimed to determine the dose-assessment accuracy of the well-established dicentric chromosome assay (DCA) and cytokinesis-block micronucleus assay (CBMN) in comparison to the emerging γ-H2AX foci and gene expression assays for triage mode biodosimetry and radiation injury assessment. Coded blood samples exposed to 10 X-ray doses (240 kVp, 1 Gy/min) of up to 6.4 Gy were sent to participants for dose estimation. Report times were documented for each laboratory and assay. The mean absolute difference (MAD) of estimated doses relative to the true doses was calculated. We also merged doses into binary dose categories of clinical relevance and examined accuracy, sensitivity and specificity of the assays. Dose estimates were reported by the first laboratories within 0.3-0.4 days of receipt of samples for the γ-H2AX and gene expression assays compared to 2.4 and 4 days for the DCA and CBMN assays, respectively. Irrespective of the assay we found a 2.5-4-fold variation of interlaboratory accuracy per assay and lowest MAD values for the DCA assay (0.16 Gy) followed by CBMN (0.34 Gy), gene expression (0.34 Gy) and γ-H2AX (0.45 Gy) foci assay. Binary categories of dose estimates could be discriminated with equal efficiency for all assays, but at doses ≥1.5 Gy a 10% decrease in efficiency was observed for the foci assay, which was still comparable to the CBMN assay. In conclusion, the DCA has been confirmed as the gold standard biodosimetry method, but in situations where speed and throughput are more important than ultimate accuracy, the emerging rapid molecular assays have the potential to become useful triage tools.

[Adherence between antibiotic prescriptions and guidelines in an internal medicine ward: an evaluation of professional practices]

INTRODUCTION

This is an evaluation of professional practices (EPP) on antibiotic therapy in an internal medicine ward.

MATERIAL AND METHODS

A 6-month prospective review of antibiotic prescriptions and their comparisons with local and national guidelines (drug, daily dose, administration, and duration) were performed.

RESULTS

Antibiotic therapy on 227 infectious episodes was collected. According to local guidelines, we found 56% of totally respected (lower respiratory tract infections: 38%, urinary tract infections: 88% and skin infections: 73%), 33% of partially respected and 11% of non-appropriate prescriptions. Considering national guidelines for lower respiratory tract infections as references, the results were: totally respected prescriptions 81%, partially respected prescriptions 16%, and non-appropriate prescriptions 3%.

CONCLUSION

This evaluation of the prescriptions allowed setting up long-lasting actions to improve clinical practice. This approach anticipates the procedures of EPP that will be needed for hospital accreditation and highlights the importance of considering several guidelines for the interpretation of the results.

Genome scans reveal candidate regions involved in the adaptation to host plant in the pea aphid complex

A major goal in evolutionary biology is to uncover the genetic basis of adaptation. Divergent selection exerted on ecological traits may result in adaptive population differentiation and reproductive isolation and affect differentially the level of genetic divergence along the genome. Genome-wide scan of large sets of individuals from multiple populations is a powerful approach to identify loci or genomic regions under ecologically divergent selection. Here, we focused on the pea aphid, a species complex of divergent host races, to explore the organization of the genomic divergence associated with host plant adaptation and ecological speciation. We analysed 390 microsatellite markers located at variable distances from predicted genes in replicate samples of sympatric populations of the pea aphid collected on alfalfa, red clover and pea, which correspond to three common host-adapted races reported in this species complex. Using a method that accounts for the hierarchical structure of our data set, we found a set of 11 outlier loci that show higher genetic differentiation between host races than expected under the null hypothesis of neutral evolution. Two of the outliers are close to olfactory receptor genes and three other nearby genes encoding salivary proteins. The remaining outliers are located in regions with genes of unknown functions, or which functions are unlikely to be involved in interactions with the host plant. This study reveals genetic signatures of divergent selection across the genome and provides an inventory of candidate genes responsible for plant specialization in the pea aphid, thereby setting the stage for future functional studies.

Effects of urban particulate deposition on microbial communities living in bryophytes: an experimental study

Our previous in situ study showed that bryophyte-microorganism complexes were affected by particulate atmospheric pollution. Here, the effect of urban particulate wet deposits on microbial communities living in bryophytes was studied under controlled conditions. An urban particulate solution was prepared with particles extracted from analyzer' filters and nebulized on bryophytes in treatments differing in frequency and quantity. The bryophytes did not accumulate metallic trace elements, which were present in very weak concentrations. However, in treated microcosms the total microbial biomass and the biomasses of cyanobacteria, active testate amoebae and fungi significantly decreased in response to the deposition of particles. These results confirm that microbial communities living in terrestrial bryophytes could be more sensitive indicators of atmospheric pollution than bryophytes. Moreover, they suggest that unicellular predators--such as testate amoebae--could be especially useful microbial indicators, since they seem to be both directly and indirectly affected by pollution.

Effect of lead pollution on testate amoebae communities living in Sphagnum fallax: an experimental study

We studied the effects of lead pollution on testate amoebae communities living on Sphagnum fallax by growing this moss under controlled conditions. A progressive series of lead (Pb) concentration was used in the growing solution of the mosses: 0 (control), 625 and 2,500 microgL(-1). The mosses were sampled and analysed for accumulated Pb and testate amoeba communities after 0, 6, 12, and 20 weeks. Species richness, total density and total biomass of testate amoebae declined in response to the Pb treatment and changed over time. The Pb x Time cross-effect was significant for species richness, and total density but not for the total biomass and Shannon diversity. Furthermore, the testate amoebae species richness and the total density were negatively correlated to the Pb concentrations actually accumulated in the moss at the end of the experiment. Species-specific responses of testate amoebae to Pb pollution were identified. Our results thus confirm the sensitivity of testate amoebae to lead pollution.

Effects of experimental lead pollution on the microbial communities associated with Sphagnum fallax (Bryophyta)

Ecotoxicological studies usually focus on single microbial species under controlled conditions. As a result, little is known about the responses of different microbial functional groups or individual species to stresses. In an aim to assess the response of complex microbial communities to pollution in their natural habitat, we studied the effect of a simulated lead pollution on the microbial community (bacteria, cyanobacteria, protists, fungi, and micrometazoa) living on Sphagnum fallax. Mosses were grown in the laboratory with 0 (control), 625, and 2,500 microg L(-1) of Pb(2+) diluted in a standard nutrient solution and were sampled after 0, 6, 12, and 20 weeks. The biomasses of bacteria, microalgae, testate amoebae, and ciliates were dramatically and significantly decreased in both Pb addition treatments after 6, 12, and 20 weeks in comparison with the control. The biomass of cyanobacteria declined after 6 and 12 weeks in the highest Pb treatment. The biomasses of fungi, rotifers, and nematodes decreased along the duration of the experiment but were not significantly affected by lead addition. Consequently, the total microbial biomass was lower for both Pb addition treatments after 12 and 20 weeks than in the controls. The community structure was strongly modified due to changes in the densities of testate amoebae and ciliates, whereas the relative contribution of bacteria to the microbial biomass was stable. Differences in responses among the microbial groups suggest changes in the trophic links among them. The correlation between the biomass of bacteria and that of ciliates or testate amoebae increased with increasing Pb loading. We interpret this result as an effect on the grazing pathways of these predators and by the Pb effect on other potential prey (i.e., smaller protists). The community approach used here complements classical ecotoxicological studies by providing clues to the complex effect of pollutant-affecting organisms both directly and indirectly through trophic effects and could potentially find applications for pollution monitoring.

[Incidence and reasons of premature discontinuation of abacavir: results of a hospital investigation among 628 patients]

OBJECTIVE

The aim of this study was to determine the incidence of abacavir discontinuation within the first two months of treatment and the link with a true hypersensitivity reaction (HSR).

PATIENTS AND METHODS

A retrospective study was made between January 1998 and January 2006 on a cohort of HIV positive patients treated by abacavir delivered by the Bordeaux Saint-André University Hospital pharmacy.

RESULTS

Six hundred (and) twenty-eight patients were included. The reasons for non-renewal of abacavir prescription within the first three months of treatment were investigated. Early discontinuation for adverse effects was reported in 32 patients (5.1%): proved diagnosis of HSR (N=10), uncertain diagnosis of HSR (N=8), and no HSR (N=14). The decision for discontinuation was taken by physician after consultation in 76% of cases.

Five-Year Follow up of Once-Daily Therapy with Emtricitabine, Didanosine and Efavirenz (Montana ANRS 091 Trial)

Background

Once-daily combination therapy with emtricitabine, didanosine and efavirenz has been highly effective in clinical trials but its long-term efficacy and safety has not been previously reported.

Methods

This multicentre, single-arm, open-label trial enrolled 40 antiretroviral-naive HIV-1-infected patients who received a once-daily regimen of emtricitabine, didanosine and efavirenz. The objective was to assess the long-term effects of this combination on plasma HIV RNA levels, CD4+ T-cell counts, safety and tolerability.

Results

After 5 years, 73% and 68% of patients had plasma HIV RNA levels <400 and <50 copies/ml, respectively, in an intent-to-treat, missing-equals-failure analysis. Genotypic resistance on treatment emerged in six patients. There was a significant increase in CD4+ T-cell count of 294x106 cells/l. Only six patients discontinued study treatment, because of non-severe adverse events. Lipodystrophy was infrequent, and lipid and glucose profiles were favourable with a significant increase in high-density lipoprotein cholesterol.

Conclusions

A convenient once-daily regimen of emtricitabine, didanosine and efavirenz provided durable antiretroviral response and was well tolerated through 5 years of therapy.

Liver-related mortality in human-immunodeficiency-virus-infected patients between 1995 and 2003 in the French GERMIVIC Joint Study Group Network (MORTAVIC 2003 Study)

The objective of the present study was to determine mortality because of end-stage liver disease (ESLD) in a nationwide population of HIV-infected patients, 7 years following the introduction of highly active antiretroviral therapy (HAART). All departments of internal medicine and infectious diseases from the GERMIVIC Study Group prospectively recorded all deaths in HIV-infected patients during 2003. Fifty-nine departments, following a total of 20 940 HIV-infected patients, participated in the study. Results were compared with those of previous surveys conducted using similar methodology in 1995, 1997 and 2001. Among 215 deaths observed during 2003, 101 (46.9%) were related to AIDS, 27 (12.6%) to ESLD and 87 (40.5%) to other causes. Mortality because of ESLD represented 23.7% of non-AIDS-related deaths. Patients dying from ESLD had chronic hepatitis because of hepatitis C virus (HCV) in 92.6% of cases and moderate (30-60 g) or high (>60 g) alcohol consumption (43.5% and 26.0%, respectively). In this population, deaths because of ESLD were 1.5% in 1995, 6.6% in 1997, 14.3% in 2001 and 12.6% in 2003. The prevalence of hepatocellular carcinoma as a cause of death remained high in 2003 but stable when compared with 2001 (25%vs 14.8%). Treatment of hepatitis C in patients who died from ESLD was more frequent in 2003 (44.4%) than in 2001 (26.3%). Seven years after the introduction of HAART, ESLD associated with HCV infections is a leading cause of mortality in HIV-infected patients, which did not increase between the years 2001 and 2003.

Relationship between testate amoeba (protist) communities and atmospheric heavy metals accumulated in Barbula indica (bryophyta) in Vietnam

We studied the relationships between testate amoeba communities and heavy metal (Pb, Cd, Zn, Ni, Cu, Mn, and Fe) concentrations in the moss Barbula indica sampled at 29 sites in and around the city of Hanoi (Vietnam). Our first approach was to compare the heavy metal concentrations and testate amoeba variables between the city (zone 1) and the surrounding (zone 2). Mean moss concentrations of Pb, Cd, Zn, Ni, and Cu were significantly higher and testate amoeba species richness and abundance were significantly lower in zone 1 and the abundance of eight taxa differed significantly between the two zones. We then studied the correlation between heavy metals and testate amoebae. Species richness and abundance were correlated negatively to Pb concentration. Shannon H' was negatively correlated to both Pb and Cd. The abundance of several species was negatively correlated with Pb, Cd, Zn, and Ni; however, at the community level, Pb emerged as the only significant variable in a redundancy analysis. Our results suggest that testate amoebae are sensitive to and may be good bioindicators for heavy metal pollution, especially lead. Further research is needed to understand the causal relationships underlying the observed patterns.

Lead concentrations in feathers and blood of common blackbirds (Turdus merula) and in earthworms inhabiting unpolluted and moderately polluted urban areas

Despite the dramatic decrease of atmospheric lead (Pb) concentrations in urban areas of most industrialised countries, we hypothesised that urban common blackbirds (Turdus merula) may still be contaminated by Pb concentrations of toxicological concern due to transfer from soil through the food chain. We sampled blackbirds and earthworms, one of their main preys, in Besançon, a middle-size city of Eastern France (where atmospheric Pb concentrations decreased from 0.5 microg/m(3) in 1987 to nearly 0 in 2002) and in a rural reference site. Lead concentrations were determined in the tissues of the different functional groups of earthworms (anecic, epigeous and endogeous) and in blood, washed and unwashed outermost tail feathers and breast feathers of blackbirds. Fresh masses and an index of individual body condition were measured in the two blackbird populations as biomarkers of possible toxic effects. Lead concentrations in earthworms did not differ among functional groups but were significantly higher in urban individuals than in rural ones. Concentrations in outermost tail feathers, breast feathers and blood were significantly higher in urban blackbirds (7.75+/-4.50, 3.15+/-1.77 and 0.15+/-0.09 microg/g, respectively) than in rural individuals. In urban blackbirds, concentrations in washed and unwashed outermost tail feathers allowed estimating the external contamination (probably due to deposition of dusts and/or to excretion of the uropygial gland) at 37% of the total Pb concentration of the unwashed feathers. Remaining 63% should be linked to food chain transfer of persistent Pb from urban soils. Among the 23 sampled blackbirds, 4 of them (3 in the urban site and 1 in the rural site) exhibited blood Pb concentrations higher than the benchmark value (0.20 microg/g) related to subclinical and physiological effects in birds. Variations in body condition index were not correlated to Pb concentrations in blackbird tissues. Present results suggest that Pb may still be of environmental concern for blackbirds in urban areas because of the persistence of Pb in soils and its transfer through the food chain.

Myasthenia gravis exacerbation or unmasking associated with telithromycin treatment

Telithromycin, a new ketolide antibiotic, has been implicated in the exacerbation or unmasking of myasthenia gravis. This retrospective study presents two clinical reports and summarizes eight other suspected cases notified to the French pharmacovigilance system, highlighting a potentially life-threatening risk of telithromycin treatment in myasthenic patients. An important common feature was that, in seven cases, symptomatology occurred within 2 hours of first telithromycin intake--notably in cases of severe exacerbation.