Latest Advances in Laboratory Detection of Mycoplasma genitalium.

Mycoplasma genitalium is an important sexually transmitted pathogen affecting both men and women. Its extremely slow growth in vitro and very demanding culture requirements necessitate the use of molecular-based diagnostic tests for its detection in clinical specimens. The recent availability of U.S. Food and Drug Administration (FDA)-cleared commercial molecular-based assays has enabled diagnostic testing to become more widely available in the United States and no longer limited to specialized reference laboratories. Advances in the knowledge of the epidemiology and clinical significance of M. genitalium as a human pathogen made possible by the availability of molecular-based testing have led to updated guidelines for diagnostic testing and treatment that have been published in various countries. This review summarizes the importance of M. genitalium as an agent of human disease, explains the necessity of obtaining a microbiological diagnosis, describes currently available diagnostic methods, and discusses how the emergence of antimicrobial resistance has complicated treatment alternatives and influenced the development of diagnostic tests for resistance detection, with an emphasis on developments over the past few years.

Septic polyarthritis with Mycoplasma salivarium in a patient with common variable immunodeficiency: case report and review of the literature.

Mycoplasma salivarium is a common mycoplasma usually isolated from human oropharynx, particularly from individuals with periodontal disease. It is also among the more common mycoplasmal contaminants of eukaryotic cell cultures. Although M. salivarium has been isolated occasionally from abscesses and other sterile sites, to our knowledge, only three cases of septic arthritis have been documented in the past due to this organism, all in patients with humoral immunodeficiency. We now report a fourth case of septic polyarthritis in a patient with profound hypoimmunoglobulinemia who had experienced dental abscesses within the preceding 2 years. Our case highlights the importance of considering invasive mycoplasmal infection in hypogammaglobulinemic patients. It is likely of significance that the patient had suffered recurrent dental abscesses as a source of infection with M. salivarium .

Macrolide-resistant Mycoplasma pneumoniae pneumonia in transplantation: Increasingly typical?

Mycoplasma pneumoniae is one of the most common bacterial causes of pneumonia. Macrolide-resistant M pneumoniae (MRMP) was documented in 7.5% of isolates in the United States. Resistance portends poor outcomes to macrolide therapy, yet patients respond well to fluoroquinolones or tetracyclines such as minocycline. However, MRMP may be under-appreciated because M pneumoniae generally causes relatively mild infections in non-immunosuppressed adults that may resolve without effective therapy and because microbiological confirmation and susceptibility are not routinely performed. We report two cases of pneumonia due to MRMP in kidney transplant recipients. Both patients required hospital admission, worsened on macrolide therapy, and rapidly defervesced on doxycycline or levofloxacin. In one case, M pneumoniae was only identified by multiplex respiratory pathogen panel analysis of BAL fluid. Macrolide resistance was confirmed in both cases by real-time PCR and point mutations associated with macrolide resistance were identified. M pneumoniae was isolated from both cases, and molecular genotyping revealed the same genotype. In conclusion, clinicians should be aware of the potential for macrolide resistance in M pneumoniae, and may consider non-macrolide-based therapy for confirmed or non-responding infections in patients who are immunocompromised or hospitalized.

Mycoplasma genitalium Coinfection in Women With Chlamydia trachomatis Infection.

We evaluated the prevalence of Mycoplasma genitalium coinfection in 302 chlamydia-infected women seen at a sexually transmitted disease clinic in Birmingham, AL. M genitalium coinfection was detected in 22 (7.3%). No participant characteristics predicted coinfection. Among coinfected women, M genitalium was detected again in 6 (28.6%) of 21 women returning for a 3-month follow-up visit after azithromycin treatment.

Evaluation of the ELITe InGenius PCR Platform for Detection of Mycoplasma pneumoniae.

Mycoplasma pneumoniae is the leading cause of bacterial community-acquired pneumonia in persons of all ages. Due to the fastidious nature of this bacterium and the necessary specialized growth media, nucleic acid amplification testing is currently the most reliable means for patient diagnostics. Analytical sensitivity, specificity, reproducibility, and clinical performance of the ELITe InGenius automated PCR platform with its MGB Alert M. pneumoniae real-time PCR research use only reagents (ELITechGroup, Inc., Bothell, WA) were compared with those of a laboratory-developed real-time PCR assay targeting repMp1 for detection of M. pneumoniae The ELITe InGenius PCR assay successfully detected 31 distinct M. pneumoniae clinical isolates and reference strains, and there was no cross-reactivity with other mollicutes, Gram-positive bacteria, or Gram-negative bacteria. In testing 223 clinical samples, the ELITe InGenius PCR showed 95.79% and 99.22% positive and negative agreement with the repMp1 assay, respectively. Additionally, the ELITech platform showed 98.91% positive and 96.95% negative predictive values, and there was no significant difference detected between the two assays (McNemar's test, P = 0.375). The ELITe InGenius PCR assay limit of detection was 0.16 CFU/PCR test or 4.16 genome copies (GCs)/test. Accuracy, instrument ease-of-use, and decreased hands-on time make the ELITe InGenius platform suitable for detection of M. pneumoniae directly from clinical specimens.

Two cases of multidrug-resistant genitourinary Mycoplasma genitalium infection successfully eradicated with minocycline.

Mycoplasma genitalium (MG) infection is a sexually transmitted infection that causes up to 25% of nongonococcal urethritis (NGU). MG strains carrying genetic markers of antimicrobial resistance that may affect treatment outcomes are increasingly recognized as a public health concern. We present two cases of persistent MG NGU with strains carrying both macrolide and quinolone resistance-associated mutations that were eradicated successfully by an extended course of minocycline.

Evaluation of a real-time PCR assay for detection of Mycoplasma genitalium and macrolide resistance-mediating mutations from clinical specimens.

Mycoplasma genitalium (MG) is a sexually transmitted pathogen for which there is no FDA-approved diagnostic test available in the United States. A modified real-time polymerase chain reaction assay for detecting MG and simultaneously identifying macrolide resistance mutations from clinical specimens was evaluated and proved to be sensitive and accurate for diagnostic purposes.

Analysis of the tonsillar microbiome in young adults with sore throat reveals a high relative abundance of Fusobacterium necrophorum with low diversity.

Fusobacterium necrophorum (Fn), a gram-negative anaerobe, is increasingly implicated as an etiologic agent in older adolescents and young adults with sore throat. Inadequately treated Fn pharyngitis may result in suppurative complications such as peritonsillar abscess and Lemierre's syndrome. Data from the literature suggest that the incidence of life-threating complications in these age groups from Fn pharyngitis (Lemierre's syndrome) in the United States exceeds those associated with group A beta-hemolytic streptococcal (GAS) pharyngitis (acute rheumatic fever). Using real-time PCR, we previously reported about a 10% prevalence of Fn in asymptomatic medical students and about 20% in students complaining of sore throat at a university student health clinic (p = 0.009). In this study, a comprehensive microbiome analysis of the same study samples confirms that Fn pharyngitis was more common than GAS pharyngitis. Eighteen patients were found to have Fn OTU values exceeding an arbitrary cutoff value of 0.1, i.e. greater than 10% of total sequences, with five subjects reaching values above 0.7. By contrast only 9 patients had GAS OTU values greater than 0.1 and none exceeded 0.6. When the data were analyzed using five separate assessments of alpha diversity, in each case for Fn there were statistically significant differences between Fn positive_high (OTU abundance > 0.1) vs control, Fn positive_high vs Fn negative (OTU abundance = 0), Fn positive_high vs Fn positive_low (OTU abundance > 0 and < 0.1). When the data were analyzed using three beta diversity indexes (Bray-Curtis, weighted unifrac, and unweighted unifrac), there were statistically significant differences between Fn positive_high (OTU abundance ≥ 0.1) vs control for all three. Statistically significant differences remained if we chose somewhat different OTU abundance cutoffs of 0.05 or 0.15. We conclude that Fn appears to play a dominant role in bacterial pharyngitis in the older adolescent and young adult age groups and that the development of a productive mucosal infection with Fn is linked to a significant decrease in the diversity of the associated tonsillar microbiome.

Mycoplasma hominis Infections Transmitted Through Amniotic Tissue Product.

Background: Mycoplasma hominis is a commensal genitourinary tract organism that can cause infections outside the genitourinary tract. We investigated a cluster of M. hominis surgical site infections in patients who underwent spine surgery, all associated with amniotic tissue linked to a common donor. Methods: Laboratory tests of tissue product from the donor, including culture, quantitative real-time polymerase chain reaction (qPCR), and whole-genome sequencing were performed. Use of this amniotic tissue product was reviewed. A multistate investigation to identify additional cases and locate any unused products was conducted. Results: Twenty-seven tissue product vials from a donor were distributed to facilities in 7 states; at least 20 vials from this donor were used in 14 patients. Of these, 4 of 14 (29%) developed surgical site infections, including 2 M. hominis infections. Mycoplasma hominis was detected by culture and qPCR in 2 unused vials from the donor. Sequencing indicated >99% similarity between patient and unopened vial isolates. For 5 of 27 (19%) vials, the final disposition could not be confirmed. Conclusions: Mycoplasma hominis was transmitted through amniotic tissue from a single donor to 2 recipients. Current routine donor screening and product testing does not detect all potential pathogens. Clinicians should be aware that M. hominis can cause surgical site infections, and may not be detected by routine clinical cultures. The lack of a standardized system to track tissue products in healthcare facilities limits the ability of public health agencies to respond to outbreaks and investigate other adverse events associated with these products.

Shaken or stirred?: Comparison of methods for dispersion of Mycoplasma pneumoniae aggregates for persistence in vivo.

BACKGROUND: Mycoplasma pneumoniae (Mpn), one of the smallest self-replicating prokaryotes, is known to readily adhere to host cells and to form aggregates in suspension. Having only one cell membrane and no cell wall, mycoplasmas present questions as to optimal aggregate disruption method while minimizing cell death in vitro. We compared conventional vortex mixing with other methods for disruption of bacterial aggregates and for its effect on cell viability. METHODS: Strain UAB PO1, a clinical Mpn isolate, was dispersed using a conventional vortex mixer with or without nonionic detergent (0.1% and 0.01% Tween-20), a probe-type ultrasonicator, or repeated passage through a 27-gauge needle. The resulting suspensions were assayed for recoverable colony-forming units (CFU). Flow cytometric assays were carried out to examine particle size and membrane integrity with the transmembrane potential dye DiBAC4. Wet Scanning Transmission Electron Microscopy (Wet-STEM) was performed for high resolution imaging of the resultant cell suspensions. Additional Mpn strains and other human mollicute species were assayed in a similar manner. Mice were infected with either vortexed or sonicated UAB PO1 and bacterial persistence was examined via Mpn-specific 16S qPCR. RESULTS: Comparison between dispersion methods showed a 10-fold enrichment of recoverable Mpn CFU with sonication compared to other methods. Time-course analysis showed significantly lower bacterial CFU with vortexing compared to sonication at all time points. Flow cytometric analysis showed increased cellular membrane damage via DiBAC4 staining in sonicated suspensions, but a decreased particle size. Wet-STEM imaging showed markedly improved dispersion with sonication compared to conventional vortex treatment, and surprisingly vortexing for 30s produced up to a 100-fold drop in CFU. Results similar to UAB PO1 were obtained with three additional Mpn strains and other Mollicutes species, although they exhibited differential susceptibilities to disaggregation by sonication. Finally, increased persistence of the organism in a mouse model of infection was observed using sonicated suspensions for initial infection. CONCLUSIONS: Sonication is superior to vortexing with or without nonionic detergent or repeated 27-gauge needle passage for dispersion of Mpn aggregates while preserving cell viability. Preparation of Mpn suspensions for in vivo experiments is best accomplished using brief sonication due to the dramatic increase in CFU produced by sonication. Dispersion methods may affect the final experimental results and should be an important consideration for future research involving mycoplasma species.

Macrolide-Resistant Mycoplasma pneumoniae, United States.

Macrolide-resistant Mycoplasma pneumoniae (MRMP) is highly prevalent in Asia and is now being reported from Europe. Few data on MRMP are available in the United States. Using genotypic and phenotypic methods, we detected high-level MRMP in 13.2% of 91 M. pneumoniae--positive specimens from 6 US locations.

Specificity and Strain-Typing Capabilities of Nanorod Array-Surface Enhanced Raman Spectroscopy for Mycoplasma pneumoniae Detection.

Mycoplasma pneumoniae is a cell wall-less bacterial pathogen of the human respiratory tract that accounts for > 20% of all community-acquired pneumonia (CAP). At present the most effective means for detection and strain-typing is quantitative polymerase chain reaction (qPCR), which can exhibit excellent sensitivity and specificity but requires separate tests for detection and genotyping, lacks standardization between available tests and between labs, and has limited practicality for widespread, point-of-care use. We have developed and previously described a silver nanorod array-surface enhanced Raman Spectroscopy (NA-SERS) biosensing platform capable of detecting M. pneumoniae with statistically significant specificity and sensitivity in simulated and true clinical throat swab samples, and the ability to distinguish between reference strains of the two main genotypes of M. pneumoniae. Furthermore, we have established a qualitative lower endpoint of detection for NA-SERS of < 1 genome equivalent (cell/µl) and a quantitative multivariate detection limit of 5.3 ± 1 cells/µl. Here we demonstrate using partial least squares- discriminatory analysis (PLS-DA) of sample spectra that NA-SERS correctly identified M. pneumoniae clinical isolates from globally diverse origins and distinguished these from a panel of 12 other human commensal and pathogenic mycoplasma species with 100% cross-validated statistical accuracy. Furthermore, PLS-DA correctly classified by strain type all 30 clinical isolates with 96% cross-validated accuracy for type 1 strains, 98% cross-validated accuracy for type 2 strains, and 90% cross-validated accuracy for type 2V strains.

The clinical presentation of Fusobacterium-positive and streptococcal-positive pharyngitis in a university health clinic: a cross-sectional study.

BACKGROUND: Pharyngitis guidelines focus solely on group A ß-hemolytic streptococcal infection. European data suggest that in patients aged 15 to 30 years, Fusobacterium necrophorum causes at least 10% of cases of pharyngitis; however, few U.S. data exist. OBJECTIVE: To estimate the prevalence of F. necrophorum; Mycoplasma pneumoniae; and group A and C/G ß-hemolytic streptococcal pharyngitis and to determine whether F. necrophorum pharyngitis clinically resembles group A ß-hemolytic streptococcal pharyngitis. DESIGN: Cross-sectional. SETTING: University student health clinic. PATIENTS: 312 students aged 15 to 30 years presenting to a student health clinic with an acute sore throat and 180 asymptomatic students. MEASUREMENTS: Polymerase chain reaction testing from throat swabs to detect 4 species of bacteria and signs and symptoms used to calculate the Centor score. RESULTS: Fusobacterium necrophorum was detected in 20.5% of patients and 9.4% of asymptomatic students. Group A ß-hemolytic streptococcus was detected in 10.3% of patients and 1.1% of asymptomatic students. Group C/G ß-hemolytic streptococcus was detected in 9.0% of patients and 3.9% of asymptomatic students. Mycoplasma pneumoniae was detected in 1.9% of patients and 0 asymptomatic students. Infection rates with F. necrophorum, group A streptococcus, and group C/G streptococcus increased with higher Centor scores (P < 0.001). LIMITATIONS: The study focused on a limited age group and took place at a single institution. Asymptomatic students-rather than seasonal control participants-and a convenience sample were used. CONCLUSION: Fusobacterium necrophorum-positive pharyngitis occurs more frequently than group A ß-hemolytic streptococcal-positive pharyngitis in a student population, and F. necrophorum-positive pharyngitis clinically resembles streptococcal pharyngitis. PRIMARY FUNDING SOURCE: University of Alabama at Birmingham and the Justin E. Rodgers Foundation.

Comparison of the illumigene Mycoplasma DNA amplification assay and culture for detection of Mycoplasma pneumoniae.

A loop-mediated isothermal amplification (LAMP) system, the illumigene Mycoplasma DNA amplification assay (Meridian Bioscience, Inc., Cincinnati, OH) was evaluated to determine its analytical sensitivity, specificity, and clinical application in comparison to historic culture in a collection of archived respiratory specimens. The illumigene limit of detection was ≤88 CFU/reaction for 10 Mycoplasma pneumoniae reference strains. This assay correctly identified 36 M. pneumoniae reference strains and clinical isolates from various geographic origins, including both of the main subtypes. No cross-reactions were detected with other mycoplasmas, ureaplasmas, other bacterial species, viruses, yeasts, or human DNA. Among 214 respiratory specimens previously cultured for M. pneumoniae, when real-time PCR with bidirectional sequencing of the PCR products was used to resolve discrepancies, the sensitivity was 22 of 22 (100%) and the specificity was 190 of 192 (99%). This commercial LAMP assay is a useful rapid method for detecting M. pneumoniae in clinical specimens. Additional prospective clinical trials with direct comparison to culture and PCR are warranted.

Regioselective routes to disubstituted dibenzo crown ethers and their complexations.

Two isomers of bis(carbomethoxybenzo)-24-crown-8 (cis-BCMB24C8, 1, and trans-BCMB24C8, 2) were synthesized regiospecifically with acceptable to excellent yields. Cyclization in the presence of a template reagent, KPF(6), led to an essentially quantitative yield of the potassium complex of the crown ether 1; the isolated cyclization yield of pure was a remarkable 89%! The methods not only avoid the very difficult separation of the isomers, but also greatly shorten the synthesis time by eliminating syringe pump usage during cyclization. The complexations of the isomeric BCMB24C8 with dibenzylammonium hexafluorophosphate (10) were studied by NMR; association constants (Ka) for 1 and 2 with the dibenzylammonium cation are 190 and 312 M(-1), respectively. The X-ray crystal structures of crown ether and the complexes 1.KPF(6), 2.KPF(6) and pseudorotaxane 2.10 were determined.