Use of a Multiplex PCR Assay To Assess the Presence of Treponema pallidum in Mucocutaneous Ulcerations in Patients with Suspected Syphilis.

We evaluated the utility of the commercial Allplex genital ulcer real-time PCR multiplex assay for detecting Treponema pallidum, herpes simplex virus 1 (HSV-1) and 2 (HSV-2), and Chlamydia trachomatis serovar L (lymphogranuloma venereum [LGV]) DNA in mucosal and genital ulcers in the context of suspected syphilis. In total, 374 documented genital and mucosal ulcers from patients with and without syphilis presenting at several sexually transmitted infection (STI) centers in France from October 2010 to December 2016 were analyzed at the National Reference Center (CNR) for Bacterial STIs at Cochin Hospital in Paris. T. pallidum subsp. pallidum detection results were compared with the final diagnosis based on a combination of clinical examination, serological results, and in-house nested PCR (nPCR). Detections of HSV and LGV were validated against reference methods. We found that 44.6% of the 374 samples tested were positive for T. pallidum subsp. pallidum, 21% for HSV, and 0.8% for LGV. No positive results were obtained for 30.7% of samples, and 4.8% presented coinfections. For T. pallidum subsp. pallidum detection, the overall sensitivity was 80% (95% confidence interval [CI], 76.1 to 84.1%), specificity was 98.8% (95% CI, 97.7 to 99.9%), positive predictive value was 98.8% (95% CI, 97.7 to 99.9%) and negative predictive value was 80.2% (95% CI, 76.2 to 84.2%), with a rate of concordance with the reference method of 92.5% (k = 0.85). This PCR multiplex assay is suitable for T. pallidum subsp. pallidum detection in routine use and facilitates the simultaneous rapid detection of a broad panel of pathogens relevant in a context of suspected syphilis lesions.

Generation of Mycoplasma hominis gene-targeted mutants by targeting-induced local lesions in genomes (TILLING).

BACKGROUND: Mycoplasma hominis is a human urogenital pathogen involved in gynaecological, neonatal and extra-genital infections. However, no versatile genetic tools are currently available to study the pathogenicity of this bacterium. Targeting-Induced Local Lesions IN Genomes (TILLING) is a reverse-genetic method that combines point mutations induced by chemical mutagenesis with a DNA screening technique. We used ethyl methanesulfonate (EMS) that introduces C-G to T-A transition mutations to generate a library of M. hominis mutants. As a proof of concept, mutagenized organisms were screened for mutations in two target genes previously associated with the mycoplasma pathogenicity, the vaa gene encoding an adhesin lipoprotein and the oppA gene encoding the main ectoATPase of the bacterium. The resulting mutants were evaluated using functional assays, an adhesion to HeLa cell assay for vaa-mutants and an ATPase activity test for oppA-mutants. RESULTS: A 1200-clone library was generated by exposing M. hominis PG21 to 9 mg/mL EMS for 3 h. To identify mutants of interest, targeted gene fragments were amplified, heat-denatured, slowly reannealed and digested with the mismatch-specific endonuclease ENDO1. If multiple alleles were present in the PCR amplicons, these alleles formed heteroduplexes during reannealing that were specifically cleaved by ENDO1 at mismatching positions. A total of four vaa-mutants and two oppA-mutants harbouring missense mutations were obtained and fully sequenced. Zero to eight additional mutations were identified in the genomes of each mutant. The vaa-mutants were tested for adhesion to immobilized HeLa cells but their adhesion was not significantly different from the adhesion of M. hominis PG21. One of the two oppA-mutants that were tested for ATPase activity presented a higher affinity for its ATP substrate than the parental strain. CONCLUSION: For the first time, we demonstrated that M. hominis gene-targeted mutants could be successfully obtained using this TILLING strategy. In the absence of robust genetic tools for studying M. hominis, the TILLING strategy that can target any gene of the genome could help to elucidate gene functions and to better understand the pathogenesis of this human pathogenic species.

Tetracycline and fluoroquinolone resistance in clinical Ureaplasma spp. and Mycoplasma hominis isolates in France between 2010 and 2015.

Objectives: As information on Ureaplasma spp. and Mycoplasma hominis resistance is currently limited, the aim of this study was to investigate the susceptibility of Ureaplasma spp. and M. hominis to tetracyclines and fluoroquinolones in France. Methods: The susceptibility of 1014 clinical isolates obtained in Bordeaux University Hospital (Bordeaux, France) between 2010 and 2015 was evaluated using two commercial kits, S.I.R. Mycoplasma (Bio-Rad) from 1 January 2010 to 5 October 2012 and MYCOFAST RevolutioN kit (ELITech Group) from 6 October 2012 to 31 December 2015. The MICs of isolates designated as resistant were determined using the broth microdilution assay. Additionally, the tet(M) gene and fluoroquinolone resistance-associated mutations were identified. Results: Among 831 Ureaplasma spp. isolates, the tetracycline, levofloxacin and moxifloxacin resistance rates were 7.5%, 1.2% and 0.1%, respectively. Among 183 M. hominis isolates, the resistance rates were 14.8%, 2.7% and 1.6% for tetracycline, levofloxacin and moxifloxacin, respectively. Over the 6 year period, no significant change in resistance to tetracycline or fluoroquinolones was observed. The tet(M) gene was found in all tetracycline-resistant isolates. All levofloxacin-resistant isolates harboured a mutation in the parC or parE genes. Isolates that were also resistant to moxifloxacin harboured an additional mutation in the gyrA gene. The MYCOFAST RevolutioN kit significantly overestimated levofloxacin and moxifloxacin resistance in Ureaplasma spp. isolates. Conclusions: Resistance to tetracycline and fluoroquinolones is limited in France in mycoplasmas but compared with a previous report in 1999-2002, a significant increase in tetracycline resistance among Ureaplasma spp. was observed. Ongoing monitoring of the antibiotic susceptibility of these urogenital mycoplasmas remains necessary.

Interaction of Mycoplasma hominis PG21 with Human Dendritic Cells: Interleukin-23-Inducing Mycoplasmal Lipoproteins and Inflammasome Activation of the Cell.

Mycoplasma hominis lacks a cell wall, and lipoproteins anchored to the extracellular side of the plasma membrane are in direct contact with the host components. A Triton X-114 extract of M. hominis enriched with lipoproteins was shown to stimulate the production of interleukin-23 (IL-23) by human dendritic cells (hDCs). The inflammasome activation of the host cell has never been reported upon M. hominis infection. We studied here the interaction between M. hominis PG21 and hDCs by analyzing both the inflammation-inducing mycoplasmal lipoproteins and the inflammasome activation of the host cell. IL-23-inducing lipoproteins were determined using a sequential extraction strategy with two nondenaturing detergents, Sarkosyl and Triton X-114, followed by SDS-PAGE separation and mass spectrometry identification. The activation of the hDC inflammasome was assessed using PCR array and enzyme-linked immunosorbent assay (ELISA). We defined a list of 24 lipoproteins that could induce the secretion of IL-23 by hDCs, 5 with a molecular mass between 20 and 35 kDa and 19 with a molecular mass between 40 and 100 kDa. Among them, lipoprotein MHO_4720 was identified as potentially bioactive, and a synthetic lipopeptide corresponding to the N-terminal part of the lipoprotein was subsequently shown to induce IL-23 release by hDCs. Regarding the hDC innate immune response, inflammasome activation with caspase-dependent production of IL-1ß was observed. After 24 h of coincubation of hDCs with M. hominis, downregulation of the NLRP3-encoding gene and of the adaptor PYCARD-encoding gene was noticed. Overall, this study provides insight into both protagonists of the interaction of M. hominis and hDCs.IMPORTANCEMycoplasma hominis is a human urogenital pathogen involved in gynecologic and opportunistic infections. M. hominis lacks a cell wall, and its membrane contains many lipoproteins that are anchored to the extracellular side of the plasma membrane. In the present study, we focused on the interaction between M. hominis and human dendritic cells and examined both sides of the interaction, the mycoplasmal lipoproteins involved in the activation of the host cell and the immune response of the cell. On the mycoplasmal side, we showed for the first time that M. hominis lipoproteins with high molecular mass were potentially bioactive. On the cell side, we reported an activation of the inflammasome, which is involved in the innate immune response.

Molecular Epidemiology of Mycoplasma pneumoniae: Genotyping Using Single Nucleotide Polymorphisms and SNaPshot Technology.

Molecular typing of Mycoplasma pneumoniae is an important tool for identifying grouped cases and investigating outbreaks. In the present study, we developed a new genotyping method based on single nucleotide polymorphisms (SNPs) selected from the whole-genome sequencing of eight M. pneumoniae strains, using the SNaPshot minisequencing assay. Eight SNPs, localized in housekeeping genes, predicted lipoproteins, and adhesin P1 genes were selected for genotyping. These SNPs were evaluated on 140 M. pneumoniae clinical isolates previously genotyped by multilocus variable-number tandem-repeat analysis (MLVA-5) and adhesin P1 typing. This method was also adapted for direct use with clinical samples and evaluated on 51 clinical specimens. The analysis of the clinical isolates using the SNP typing method showed nine distinct SNP types with a Hunter and Gaston diversity index (HGDI) of 0.836, which is higher than the HGDI of 0.583 retrieved for the MLVA-4 typing method, where the nonstable Mpn1 marker was removed. A strong correlation with the P1 adhesin gene typing results was observed. The congruence was poor between MLVA-5 and SNP typing, indicating distinct genotyping schemes. Combining the results increased the discriminatory power. This new typing method based on SNPs and the SNaPshot technology is a method for rapid M. pneumoniae typing directly from clinical specimens, which does not require any sequencing step. This method is based on stable markers and provides information distinct from but complementary to MLVA typing. The combined use of SNPs and MLVA typing provides powerful discrimination of strains.

Identification and subtyping of clinically relevant human and ruminant mycoplasmas by use of matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) recently emerged as a technology for the identification of bacteria. In this study, we aimed to evaluate its applicability to human and ruminant mycoplasmal identification, which can be demanding and time-consuming when using phenotypic or molecular methods. In addition, MALDI-TOF MS was tested as a subtyping tool for certain species. A total of 29 main spectra (MSP) from 10 human and 13 ruminant mycoplasma (sub)species were included in a mycoplasma MSP database to complete the Bruker MALDI Biotyper database. After broth culture and protein extraction, MALDI-TOF MS was applied for the identification of 119 human and 143 ruminant clinical isolates that were previously identified by antigenic or molecular methods and for subcultures of 73 ruminant clinical specimens that potentially contained several mycoplasma species. MALDI-TOF MS resulted in accurate (sub)species-level identification with a score of ≥1.700 for 96% (251/262) of the isolates. The phylogenetically closest (sub)species were unequivocally distinguished. Although mixtures of the strains were reliably detected up to a certain cellular ratio, only the predominant species was identified from the cultures of polymicrobial clinical specimens. For typing purposes, MALDI-TOF MS proved to cluster Mycoplasma bovis and Mycoplasma agalactiae isolates by their year of isolation and genome profiles, respectively, and Mycoplasma pneumoniae isolates by their adhesin P1 type. In conclusion, MALDI-TOF MS is a rapid, reliable, and cost-effective method for the routine identification of high-density growing mycoplasmal species and shows promising prospects for its capacity for strain typing.

Evaluation of the combination of the NucliSENS easyMAG and the EasyQ applications for the detection of Mycoplasma pneumoniae and Chlamydia pneumoniae in respiratory tract specimens.

Mycoplasma pneumoniae and Chlamydia pneumoniae are respiratory tract pathogens frequently involved in community-acquired pneumonia, but are fastidious microorganisms. Their direct detection mainly requires molecular amplification techniques. A nucleic acid extraction system, NucliSENS easyMAG, and a real-time nucleic acid sequence-based amplification (NASBA) technique, NucliSENS EasyQ, were recently developed by bioMérieux to detect both bacteria. The aim of our study was to compare the easyMAG/EasyQ combination with our in-house combination, MagNA Pure extraction (Roche) and real-time polymerase chain reaction (PCR), to detect both bacteria in respiratory tract specimens. The analytical specificities of both combinations were similar. A higher analytical sensitivity was found for C. pneumoniae using the easyMAG/EasyQ combination, since the easyMAG/EasyQ system detected nucleic acid extracts 10(6) times more diluted than the in-house combination. Both combinations were equivalent when detecting M. pneumoniae in positive respiratory tract samples. Finally, the easyMAG/EasyQ combination is a potential useful tool for the detection of both bacteria regarding sensitivity, specificity, monitoring, and standardization of the procedure.

Development of multiple-locus variable-number tandem-repeat analysis for molecular typing of Mycoplasma pneumoniae.

In this study we report on the development of a multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) method for the molecular typing of Mycoplasma pneumoniae. The genomic content of M. pneumoniae M129 was analyzed for VNTRs, and 5 of the 17 VNTRs identified were selected for use in an MLVA assay. The method was based on a GeneScan analysis of VNTR loci labeled with fluorescent dyes by multiplex PCR and capillary electrophoresis. This approach was applied to a collection of 265 isolates from various European countries, Japan, and Tunisia; and 26 distinct VNTR types were found. The VNTR assay was compared to the P1 adhesin PCR-restriction fragment length polymorphism (RFLP) typing method and showed a far better resolution than the P1 PCR-RFLP method. The discriminatory power of MLVA (Hunter-Gaston diversity index [HGDI], 0.915) for the 265 isolates was significantly higher than that of the P1 PCR-RFLP method (HGDI, 0.511). However, there was a correlation between the typing results obtained by MLVA and the P1 gene PCR-RFLP method. The potential value of MLVA of M. pneumoniae as an epidemiological tool is discussed, and the use of the VNTR markers in further investigations of the potential use of MLVA in outbreaks of M. pneumoniae infections is proposed.

Evaluation of five commercial real-time PCR assays for detection of Mycoplasma pneumoniae in respiratory tract specimens.

The performances of five commercial TaqMan real-time PCR assays for the detection of Mycoplasma pneumoniae in respiratory tract specimens were evaluated in comparison with an in-house real-time PCR. All kits allowed prompt and specific results, validated by the use of an internal control. The Nanogen kit showed the best clinical sensitivity.

Increased macrolide resistance of Mycoplasma pneumoniae in France directly detected in clinical specimens by real-time PCR and melting curve analysis.

OBJECTIVES: Mycoplasma pneumoniae is a common aetiological agent of community-acquired respiratory tract infections for which macrolides are the treatment of choice. In France, only two macrolide-resistant isolates were reported in 1999. In contrast, several recent data reported that macrolide-resistant M. pneumoniae isolates have been spreading since 2000 in Japan. Mutations A2058G (Escherichia coli numbering), A2058C, A2059G, A2062G, C2611A and C2611G in domain V of the 23S rRNA gene were associated in vivo or in vitro with this resistance. The aim of this study was to determine whether macrolide resistance of M. pneumoniae is emerging in France. PATIENTS AND METHODS: We developed a duplex real-time PCR for the detection of the six 23S rRNA mutations associated with macrolide resistance in M. pneumoniae and a simplex real-time PCR for the identification of the A2058G mutation, the most common one. Both methods rely on fluorescence resonance energy transfer coupled to melting curve analysis and are directly applicable to clinical samples. The duplex real-time PCR assay, first validated on 40 genetically characterized M. pneumoniae strains, was then applied directly on 248 French respiratory tract clinical samples. RESULTS: Among M. pneumoniae-positive specimens collected before 2005, no macrolide-resistant M. pneumoniae isolate was detected. In contrast, among 51 samples collected between 2005 and 2007, five (9.8%) yielded a resistant genotype, suggesting a recent increase in macrolide-resistant M. pneumoniae isolates in France. CONCLUSIONS: The epidemiological monitoring of macrolide resistance in this species has become necessary in France and Europe, and will be made easier by using these PCR assays.

The vaginal microbiota and its association with human papillomavirus, Chlamydia trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium infections: a systematic review and meta-analysis.

BACKGROUND: The vaginal microbiota may modulate susceptibility to human papillomavirus (HPV), Chlamydia trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium infections. Persistent infection with a carcinogenic HPV is a prerequisite for cervical cancer, and C. trachomatis, N. gonorrheae and M. genitalium genital infections are all associated with pelvic inflammatory disease and subsequent infertility issues. OBJECTIVES: To evaluate the association between these infections and the vaginal microbiota. DATA SOURCES: The search was conducted on Medline and the Web of Science for articles published between 2000 and 2016. STUDY ELIGIBILITY CRITERIA: Inclusion criteria included a measure of association for vaginal microbiota and one of the considered STIs, female population, cohort, cross-sectional and interventional designs, and the use of PCR methods for pathogen detection. METHODS: The vaginal microbiota was dichotomized into high-Lactobacillus vaginal microbiota (HL-VMB) and low-Lactobacillus vaginal microbiota (LL-VMB), using either Nugent score, Amsel's criteria, presence of clue cells or gene sequencing. A random effects model assuming heterogeneity among the studies was used for each STI considered. RESULTS: The search yielded 1054 articles, of which 39 met the inclusion criteria. Measures of association with LL-VMB ranged from 0.6 (95% CI 0.3-1.2) to 2.8 (95% CI 0.3-28.0), 0.7 (95% CI 0.4-1.2) to 5.2 (95% CI 1.9-14.8), 0.8 (95% CI 0.5-1.4) to 3.8 (95% CI 0.4-36.2) and 0.4 (95% CI 0.1-1.5) to 6.1 (95% CI 2.0-18.5) for HPV, C. trachomatis, N. gonorrhoeae and M. genitalium infections, respectively. CONCLUSIONS: Although no clear trend for N. gonorrhoeae and M. genitalium infections could be detected, our results support a protective role of HL-VMB for HPV and C. trachomatis. Overall, these findings advocate for the use of high-resolution characterization methods for the vaginal microbiota and the need for longitudinal studies to lay the foundation for its integration in prevention and treatment strategies.

High prevalence of Mycoplasma genitalium infection and macrolide resistance in patients enrolled in HIV pre-exposure prophylaxis program.

OBJECTIVES: Limited data on Mycoplasma genitalium infection has been reported among PrEP users. The aim of this study was to estimate the prevalence and macrolide resistance of M. genitalium infection among enrollees in a French PrEP program. PATIENTS AND METHODS: M. genitalium infection screening was systematically and prospectively proposed to patients of the Bordeaux PrEP program (between January 2016 and February 2017). Macrolide resistance was evaluated in M. genitalium-positive patients. RESULTS: Among 89 clients, M. genitalium infection prevalence was 10% (mainly asymptomatic) with a high rate of macrolide resistance (58%). CONCLUSIONS: Because of a high level of macrolide resistance, a systematic search for M. genitalium macrolide resistance associated-mutations may be recommended in PrEP users before initiating the antibiotic therapy.

[Pathogenesis and laboratory diagnosis of Mycoplasma pneumoniae infections]. / Physiopathologie et diagnostic des infections àMycoplasma pneumoniae.

Mycoplasma pneumoniae is the only mycoplasma clearly involved in respiratory tract infections in man. Implicated most often in tracheobronchitis, it is the second most frequent agent responsible for community-wide bacterial pneumonia, and in addition it probably causes asthma exacerbations. M. pneumoniae infection occurs endemically, with epidemic peaks every four to seven years, mostly in children above five years of age. The laboratory diagnosis of these infections, mainly by serology, is made only in severe cases because of the fastidious growth of this microorganism. M. pneumoniae can, however, be detected easily by molecular amplification techniques. Macrolides and related antibiotics are considered the treatment of choice for M. pneumoniae infection in both adults and children. Antibiotic sensitivity testing of M. pneumoniae is not done routinely because resistant isolates have only rarely been described, the results are delayed, and they have no immediate therapeutic consequence.

Impact of the introduction of a nucleic acid amplification test for Clostridium difficile diagnosis on stool rejection policies.

BACKGROUND: The change from non-molecular to nucleic acid amplification tests (NAATs) is known to increase the detection of Clostridium difficile infection (CDI); however, the impact on stool rejection policies in clinical laboratories is unclear. The current guidelines have reinforced the importance of respecting strict conditions for performing tests on stool samples for CDI diagnosis. The purpose of this study was to estimate whether the implementation of molecular tests has resulted in changes in stool rejection policies between clinical laboratories that introduced NAATs and those that did not. RESULTS: A survey was conducted to evaluate the change in the number of stool samples rejected and the rejection criteria among 12 hospital laboratories in southwestern France before and after the switch from non-molecular tests to NAATs using retrospective data from June 1 till September 30, 2013 and the same period 2014. Four laboratories introduced NAATs as a second or third step in the process. A total of 1378 and 1297 stools samples were collected in 2013 and 2014, respectively. The mean number of rejected stool samples significantly increased (p < 0.001, Chi square test), with a total of 99 (7.1%) and 147 (11.3%) specimens rejected in 2013 and 2014, respectively. Notably, these laboratories had more stringent criteria and were no longer testing the stool samples of patients with CDI-positive results within 7 days. In contrast, there was a significant decrease in the rate of rejected stool samples (p < 0.001, Chi square test) in the five laboratories that did not adopt NAATs and a less stringent stool rejection policy. CONCLUSION: Nucleic acid amplification test implementation improved compliance with recommended stool rejection policies. Laboratories should follow the recommended laboratory algorithm for the CDI diagnosis combined with the correct stool rejection policy.

Observational study of anorectal Chlamydia trachomatis infections in France through the lymphogranuloma venereum surveillance network, 2010-2015.

The objective of this article is to describe the epidemiology of lymphogranuloma venereum (LGV) and non-LGV Chlamydia trachomatis anorectal infections in France and to examine the characteristics of the affected populations via a voluntary sentinel surveillance system for LGV between 2010 and 2015. Anorectal samples positive for C. trachomatis (CT) were sent by the participating laboratories to the National Reference Center for CT for LGV identification. Biological and clinical data were collected by biologists and clinicians. There were 1740 LGV episodes and 2248 non-LGV episodes. Continuous monitoring highlighted a sharp increase in the number of LGV and non-LGV anorectal infections, which were 2.3-fold and 6.5-fold, respectively. Most of the infections occurred in men who have sex with men. LGV patients were older than non-LGV patients and were more frequently human immunodeficiency virus (HIV)-positive compared to non-LGV patients. Anorectal LGV was significantly associated with residence in Paris, HIV co-infection, concurrent syphilis and bloody anal discharge. Undocumented patient characteristics were strongly associated with anorectal LGV. The anorectal LGV epidemic is poorly controlled in France. Early detection and prompt treatment of patients and their sexual partners are required to prevent transmission in the context of pre-exposure prophylaxis (PrEP) for HIV infection.

Development of a real-time PCR for the identification of Bordetella pertussis and Bordetella parapertussis.

This study describes a real-time PCR assay for the detection and identification of Bordetella pertussis and Bordetella parapertussis. The assay is based on amplification of a fragment from the repeat sequence regions IS481 and IS1001 found in B. pertussis and B. parapertussis, respectively, with subsequent species identification by melting curve analysis using SYBR Green chemistry. Discrimination between the two species was straightforward, as the corresponding melting points showed a significant difference of 7 degrees C. The assay was evaluated first with reference strains and retrospective human clinical samples, and then prospectively with 132 human clinical specimens received between March 2003 and December 2005. The assay allowed the rapid detection of 22 positive clinical samples, of which 15, including one fatal case, were not identified by standard culture techniques. The new assay was sensitive and specific, and can be implemented easily using any real-time PCR apparatus.

Quality assessment of conjunctival specimens for detection of Chlamydia trachomatis by PCR in children with active trachoma.

One component of control programmes to eliminate trachoma is the treatment of Chlamydia trachomatis infection. A diagnosis of trachoma is based on clinical grounds, but the signs of active trachoma do not always correlate with the presence of C. trachomatis. During a therapeutic trial, the level of C. trachomatis infection in children with active trachoma in Guinea and Pakistan was assessed using a qualitative commercially available PCR that targeted the C. trachomatis plasmid. The influence of the quality of specimens on the efficiency of the PCR was investigated using two quantitative real-time PCRs targeting the specific omp1 gene of C. trachomatis and human chromosomal DNA, respectively. C. trachomatis was detected in c. 23% of children (aged 1-10 years) who presented with clinically active trachoma. Controls showed that PCR-related problems did not influence this detection rate. For 14% of the positive samples, C. trachomatis was detected in only one eye, with a significantly lower mean load of bacteria. These results suggest that epidemiological and therapeutic surveys should be conducted by sampling and testing both eyes. Moreover, the high variability of the cell load observed in the conjunctival swabs suggests that the effectiveness of swabbing may be questionable.

Characterisation of in vitro-selected mutants of Ureaplasma parvum resistant to macrolides and related antibiotics.

Resistant mutants of Ureaplasma parvum were selected by serial passages of a susceptible strain in subinhibitory concentrations of different macrolides and related antibiotics (erythromycin, azithromycin, josamycin, quinupristin, quinupristin/dalfopristin, pristinamycin and telithromycin). Mechanisms of resistance were characterised by sequencing portions of genes encoding 23S rRNA and ribosomal proteins L4 and L22. Mutants with significantly increased minimum inhibitory concentrations could be selected with all the selector antibiotics, except quinupristin and pristinamycin. Mutants harboured mutations in domain V of the 23S rRNA gene at nucleotides G2056, G2057 or A2058 (Escherichia coli numbering) and in conserved portions of ribosomal proteins L4 and L22. Most of the mutations were associated with complete loss of macrolide and ketolide activity, whereas streptogramin combinations were less affected.

Contribution of tap water to patient colonisation with Pseudomonas aeruginosa in a medical intensive care unit.

This study examined tap water as a source of Pseudomonas aeruginosa in a medical intensive care setting. We prospectively screened specimens of patients, tap water and hands of healthcare workers (HCWs) over a six-month period in a 16-bed medical intensive care unit. Molecular relatedness of P. aeruginosa strains was investigated by pulsed-field gel electrophoresis. A total of 657 tap water samples were collected from 39 faucets and 127 hands of HCWs were sampled. P. aeruginosa was found in 11.4% of 484 tap water samples taken from patients' rooms and in 5.3% of 189 other tap water samples (P<0.01). P. aeruginosa was isolated from 38 patients. Typing of 73 non-replicate isolates (water samples, hands of HCWs and patients) revealed 32 major DNA patterns. Eleven (52.4%) of the 21 faucets were contaminated with a patient strain, found before isolation from tap water in the corresponding room in nine cases, or from the neighbouring room in two cases. Among seven P. aeruginosa strains isolated from HCW hands, the genotype obtained was the same as that from the last patient they had touched in six cases, and in the seventh with the last tap water sample used. More than half of P. aeruginosa carriage in patients was acquired via tap water or cross-transmission. Carriage of P. aeruginosa by patients was both the source and the consequence of tap water colonisation. These results emphasise the need for studies on how to control tap water contamination.

French situation concerning the Swedish Chlamydia trachomatis variant.

In 2006, a plasmid deletion mutant of Chlamydia trachomatis was identified in Sweden that can not be detected with those commercial tests targeting the deleted area. In order to study the spread of this strain in France, a laboratory-based surveillance system was set up by the National Reference Centre for Chlamydiae and the Institut de Veille Sanitaire. Among 1,141 C. trachomatis-positive specimens from all over France, the new variant was only detected in one case. This case was a non-French resident consulting a sexually transmitted infections clinic. Although the new variant does not seem to be established in France as yet, surveillance based on the testing of C. trachomatis-positive samples from all over France continues.