Chloé Le Roy

Non-Nociceptive Environmental Stress Induces Hyperalgesia, Not Analgesia, in Pain and Opioid-Experienced Rats

It is well admitted that stress induces analgesia (SIA) via endogenous opioid release. However, there is evidence that stressful events play a role in the pathogenesis of pain, but little is known about mechanisms underlying such pain vulnerability. Previous studies reported that a single opioid exposure activates NMDA-dependent pronociceptive systems leading to long-term pain vulnerability after analgesia. Here, we studied whether prior inflammatory pain or/and opioid experiences may favour the development of pain vulnerability after non-nociceptive environmental stress (NNES). Nociceptive threshold (NT) changes were evaluated by paw pressure vocalization test. By contrast to discrete SIA observed in naive rats, 1 h stress induced hyperalgesia (SIH) for several hours (15–65% NT decrease) in pain and opioid experienced rats. Repetition of NNES induced an 18- to 22-fold SIH enhancement (3–4 days), whereas SIA decreased. SIH was still observed 4 months after pain and opioid experiences. This phenomenon is referred to as latent pain sensitization. Furthermore, a fentanyl ultra-low dose (ULD, 50 ng/kg) administration, mimicking SIA in naive rats, induced hyperalgesia (65% NT decrease, 4 h), not analgesia, in pain and opioid-experienced rats. This indicates that low levels of opioids induce opposite effects, that is analgesia vs hyperalgesia dependent on prior life events. In pain and opioid-experienced rats, NMDA receptor antagonists, ketamine or BN2572, completely prevented hyperalgesia when injected just before NNES or fentanyl ULD. This latent pain sensitization model may be important for studying the transition from acute to chronic pain and individual differences in pain vulnerability associated with prior life events.

Endogenous Opioids Released During Non-Nociceptive Environmental Stress Induce Latent Pain Sensitization Via a NMDA-Dependent Process

UNLABELLED Although stress induces analgesia, there is evidence that stressful events may exacerbate pain syndromes. Here, we studied the effects of 1 to 3 prestressful events (days 0, 2, and 7), such as non-nociceptive environmental stress, on inflammatory hyperalgesia induced by a carrageenan injection (day 14) in 1 rat hind paw. Changes in nociceptive threshold were evaluated by the paw pressure vocalization test. The higher the number of stress sessions presented to the rats, the greater was the inflammatory hyperalgesia. Blockade of opioid receptors by naltrexone before each stress inhibited stress-induced analgesia and suppressed the exaggerated inflammatory hyperalgesia. Stressed versus nonstressed animals could be discriminated by their response to a fentanyl ultra-low dose (fULD), that produced hyperalgesia or analgesia, respectively. This pharmacological test permitted the prediction of the pain vulnerability level of prestressed rats because fULD analgesic or hyperalgesic indices were positively correlated with inflammatory hyperalgesic indices (r(2) = .84). In prestressed rats, fULD-induced hyperalgesia and the exaggerated inflammatory hyperalgesia were prevented NMDA receptor antagonists. This study provides some preclinical evidence that pain intensity is not only the result of nociceptive input level but is also dependent on the individual history, especially prior life stress events associated with endogenous opioid release. PERSPECTIVE Based on these preclinical data, it would be of clinical interest to evaluate whether prior stressful events may also affect further pain sensation in humans. Moreover, this preclinical model could be a good tool for evaluating new therapeutic strategies for relieving pain hypersensitivity.

Evaluation of Two Commercial Real-Time PCR Assays for Detection of Mycoplasma genitalium in Urogenital Specimens

ABSTRACT The performance of two commercial real-time PCR kits for the detection of Mycoplasma genitalium was evaluated in comparison to an in-house real-time PCR assay. Concordances of 96% and 93% were found for the TIB MOLBIOL and the Diagenode assays, respectively, compared to the results of the in-house assay.

Fluoroquinolone-Resistant Mycoplasma genitalium, Southwestern France

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Prevalence and Macrolide Resistance of Mycoplasma genitalium in South African Women

Remnant specimens from 601 women obtained in a cross-sectional study from rural South Africa were tested for Mycoplasma genitalium. Overall, 10.8% of women were infected with M. genitalium either in the vagina or in the rectum. Macrolide resistance, although of low prevalence, in M. genitalium is described for the first time in Sub-Saharan Africa.

MLVA subtyping of genovar E Chlamydia trachomatis individualizes the Swedish variant and anorectal isolates from men who have sex with men.

This study describes a new multilocus variable number tandem-repeat (VNTR) analysis (MLVA) typing system for the discrimination of Chlamydia trachomatis genovar D to K isolates or specimens. We focused our MLVA scheme on genovar E which predominates in most populations worldwide. This system does not require culture and therefore can be performed directly on DNA extracted from positive clinical specimens. Our method was based on GeneScan analysis of five VNTR loci labelled with fluorescent dyes by multiplex PCR and capillary electrophoresis. This MLVA, called MLVA-5, was applied to a collection of 220 genovar E and 94 non-E genovar C. trachomatis isolates and specimens obtained from 251 patients and resulted in 38 MLVA-5 types. The genetic stability of the MLVA-5 scheme was assessed for results obtained both in vitro by serial passage culturing and in vivo using concomitant and sequential isolates and specimens. All anorectal genovar E isolates from men who have sex with men exhibited the same MLVA-5 type, suggesting clonal spread. In the same way, we confirmed the clonal origin of the Swedish new variant of C. trachomatis. The MLVA-5 assay was compared to three other molecular typing methods, ompA gene sequencing, multilocus sequence typing (MLST) and a previous MLVA method called MLVA-3, on 43 genovar E isolates. The discriminatory index was 0.913 for MLVA-5, 0.860 for MLST and 0.622 for MLVA-3. Among all of these genotyping methods, MLVA-5 displayed the highest discriminatory power and does not require a time-consuming sequencing step. The results indicate that MLVA-5 enables high-resolution molecular epidemiological characterisation of C. trachomatis genovars D to K infections directly from specimens.

A polyamine-deficient diet opposes hyperalgesia, tolerance and the increased anxiety-like behaviour associated with heroin withdrawal in rats.

In humans, hyperalgesia, tolerance and anxiety disorders are common symptoms during heroin withdrawal syndrome. Significant evidence supports a role of NMDA receptors in these phenomena. Because polyamines may positively modulate the functioning of NMDA receptors and mainly originate from dietary intake, one hypothesis is that a polyamine deficient diet (PD diet) may reduce withdrawal symptoms. To address this question, we investigated the ability of a PD diet to prevent or to alleviate some symptoms of withdrawal syndrome as hyperalgesia, and increased anxiety-like behaviour in rats receiving 14 once daily subcutaneous heroin injections. Here, we show that a PD diet has both preventive and curative properties for reducing certain signs of withdrawal such as hyperalgesia, tolerance and increased anxiety-like behaviour observed in rats fed with a standard diet. Moreover, in heroin-withdrawn rats which were returned to basal pain sensitivity level, hyperalgesia following acute analgesia induced by a single heroin dose was observed in heroin-treated rats fed with standard diet, not in rats fed with a PD diet. Similarly, a stress-induced hyperalgesia induced by a non-nociceptive environmental stress session was observed in heroin-treated rats fed with standard diet. In contrast, a stress-induced analgesia was observed in heroin-treated rats fed with a PD diet, as it was observed in non heroin-treated rats. Since a PD diet for several weeks did not induce appreciable side-effects in rats, these preclinical results suggest that a PD diet could be an effective strategy for improving the relief of certain negative emotional states of heroin withdrawal syndrome and to allow reducing other medications generally used, such as opioid maintenance drugs.

Evaluation of a Commercial Multiplex Quantitative PCR (qPCR) Assay for Simultaneous Detection of Mycoplasma genitalium and Macrolide Resistance-Associated Mutations in Clinical Specimens

Macrolide antibiotics are the first-line treatment for Mycoplasma genitalium infections; however, macrolide resistance has increased up to 40% in several countries ([1][1][–][2][3][3]). Consequently, the 2016 European guideline on M. genitalium infections has recommended complementing the

Surface lipoproteome of Mycoplasma hominis PG21 and differential expression after contact with human dendritic cells

AIM To assess the lipoproteins that are involved in the interaction between Mycoplasma hominis and human dendritic cells. MATERIALS & METHODS The surface lipoproteome of M. hominis PG21 was characterized by using Triton X-114 extraction and LC-MS/MS identification. The transcriptional changes in lipoprotein genes upon contact with human dendritic cells were determined by using reverse transcription quantitative PCR after identification of reference genes suitable for normalization. RESULTS A large-scale overexpression of lipoprotein genes was observed with 21 upregulated transcripts. Seven genes of unknown function were M. hominis species specific and six genes were putatively associated with increased nutrient capture from the host cell and adhesion. CONCLUSION M. hominis regulates lipoprotein gene expression and may use species-specific mechanisms during the host colonization process.

Home screening compared with clinic-based screening for Chlamydiae trachomatis in France: a randomised controlled trial

Abstract Background The prevalence of sexually transmitted infections by Chlamydia trachomatis has increased during the past 10 years in France. In 2006, a national survey including biological samples showed that prevalence was highest for those aged 18–24 years: 3·6% in women and 2·4% in men. To increase C trachomatis screening, the French National Institute in Health Prevention and Education has decided to use web-based promotion of a self-collected and mailed specimen. Methods The project, named Chlamyweb, is a randomised controlled trial, with a 1:1 computer-controlled randomisation. In the control group, participants received personalised information and were invited to be screened by a health professional or in a free and anonymous screening centre. In the intervention group, a free home self-collection kit was provided. Recruitment took place through a website for prevention of sexually transmitted diseases and was supported by web advertisements from Sept 3 to Oct 16, 2012. The eligibility criteria were age 18–24 years, living in mainland France, having had sex, and having a valid email address. Sociodemographic data were obtained by a self-administered questionnaire on the website. The primary outcome was the rate of screening in each group. For the control group, outcome data were obtained with follow-up questionnaires. For the intervention group, both follow-up questionnaires and laboratory data were used. The trial is registered with the French medical authority, number 2011-A01000-41. Findings 5544 participants were randomly assigned to the control group and 5531 to the intervention group. Independence of each group was tested and proven for all variables. More women were recruited than men (sex ratio men:women 0·87). 5935 of 11 075 (54%) were students, 2119 (19%) were employed, 1521 (14%) were unemployed, 1360 (12%) were in high school or in training, and 140 (1%) were classed as other (eg, housewives, people on sick leave). 2426 of 9289 (26%) lived in the Paris region, 4110 (44%) in an urban area, 1084 (12%) in a suburban area, and 1669 (18%) in a rural area. The median number of partners in the past year was two, and 4523 of 11 075 (41%) participants had at least one new partner in the past 3 months. Most of the participants (10 224 of 11 075 [92%]) had never had C trachomatis screening before (4926 of 5152 men [96%] and 5298 of 5923 women [89%]). Rates of screening were 29·2% (1616 of 5531) in the intervention group and 8·7% (480 of 5544) in the control group. Home screening significantly increased testing compared with clinic-based screening (odds ratio [OR] 4·4, 95% CI 3·9–4·9; p Interpretation Home screening promoted on the internet led to an increase in the rate of chlamydia testing in 18–24-year-old people. Provision of a free of charge, easy to use, self-collection kit could also reduce territorial disparities in clinic-based chlamydia testing. Because of the high prevalence of C trachomatis in the young population, this system could help us to reach a wider population. Funding The Chlamyweb trial was funded by the French Institute for Health Promotion and Health Education (INPES). INPES is funded by the French Ministry of Health and National Health Insurance.