New insights into the pathogenesis and detection of Mycoplasma pneumoniae infections

Detection of Mycoplasma pneumoniae by real-time PCR

Mycoplasma pneumoniae is a significant cause of respiratory disease, accounting for approximately 20% of cases of community-acquired pneumonia. Although several diagnostic methods exist to detect M. pneumoniae in respiratory specimens, real-time PCR has emerged as a significant improvement for the rapid diagnosis of this pathogen. The method described herein details the procedure for the detection of M. pneumoniae by real-time PCR (qPCR). The qPCR assay described can be performed with three targets specific for M. pneumoniae (Mp181, Mp3, and Mp7) and one marker for the detection of the RNaseP gene found in human nucleic acid as an internal control reaction. Recent studies have demonstrated the ability of this procedure to reliably identify this agent and facilitate the timely recognition of an outbreak.

Surveillance of macrolide-resistant Mycoplasma pneumoniae in Beijing, China, from 2008 to 2012

Macrolide resistance rates of Mycoplasma pneumoniae in the Beijing population were as high as 68.9%, 90.0%, 98.4%, 95.4%, and 97.0% in the years 2008 to 2012, respectively. Common macrolide-resistant mobile genetic elements were not detected with any isolate. These macrolide-resistant isolates came from multiple clones rather than the same clone. No massive aggregation of a particular clone was found in a specific period.

Severe Hemolytic Anemia Associated with Mild Pneumonia Caused by Mycoplasma pneumonia

We report a case of M. pneumoniae infection presenting with severe hemolytic anemia in a 4-year-old girl, with a ten-day history of paleness, weakness, and nonproductive cough. She was very pale and tachycardic. However, she was not tachypneic. Chest examination showed normal breath sounds. No rhoncus or whistling was heard. As the erythrocyte sedimentation rate was excessively elevated, the differential diagnosis primarily comprised hematological malignancies. Direct Coombs' test was positive. Diagnosis of M. pneumoniae infection was confirmed by elevated levels of M. pneumoniae IgG and IgM antibodies and a chest X-ray suggestive of atypical pneumonia. The patient was treated with clarithromycin and packed red cell transfusion and showed a favorable recovery within ten days after admission. In conclusion, this case demonstrates that severe hemolytic anemia caused by M. pneumoniae is not always associated with severe pulmonary involvement, even when the respiratory infection is very mild, M. pneumoniae may be the cause of severe anemia.

Differences in the frequency of 23S rRNA gene mutations in Mycoplasma pneumoniae between children and adults with community-acquired pneumonia: clinical impact of mutations conferring macrolide resistance

We investigated the frequency and clinical significance of macrolide resistance in adult and pediatric patients with community-acquired pneumonia from a Mycoplasma pneumoniae infection. The frequency of the A2063G mutation in the 23S rRNA gene was significantly higher in children than in adults (61.3% [19/31] and 13.3% [8/60], respectively; P < 0.001). Patients with macrolide-resistant M. pneumoniae infections showed a longer duration of fever (P = 0.021) and required a longer duration of antibiotic treatment (P = 0.007).

Molecular methods for the detection of Mycoplasma and ureaplasma infections in humans: a paper from the 2011 William Beaumont Hospital Symposium on molecular pathology

Mycoplasma and Ureaplasma species are well-known human pathogens responsible for a broad array of inflammatory conditions involving the respiratory and urogenital tracts of neonates, children, and adults. Greater attention is being given to these organisms in diagnostic microbiology, largely as a result of improved methods for their laboratory detection, made possible by powerful molecular-based techniques that can be used for primary detection in clinical specimens. For slow-growing species, such as Mycoplasma pneumoniae and Mycoplasma genitalium, molecular-based detection is the only practical means for rapid microbiological diagnosis. Most molecular-based methods used for detection and characterization of conventional bacteria have been applied to these organisms. A complete genome sequence is available for one or more strains of all of the important human pathogens in the Mycoplasma and Ureaplasma genera. Information gained from genome analyses and improvements in efficiency of DNA sequencing are expected to significantly advance the field of molecular detection and genotyping during the next few years. This review provides a summary and critical review of methods suitable for detection and characterization of mycoplasmas and ureaplasmas of humans, with emphasis on molecular genotypic techniques.

Mycoplasmal panencephalitis: a neuropathologic documentation

Mycoplasmas, particularly Mycoplasma pneumoniae, have been implicated as causative agents in a large variety of central nervous system diseases, especially acute childhood encephalitis. Postulated pathomechanisms for mycoplasma-mediated neurological disease have included: direct infection, autoimmunity, and vascular occlusion. Neuropathologic data are meager and are reviewed. We report a 3-year-old boy, who developed signs and symptoms of encephalitis 7 days after the onset of fever with cough and death 5 days later. At autopsy, he displayed diffuse vasogenic edema and perivascular to infiltrative inflammatory cells, the latter most prominent in gray matter of brainstem and amygdala. The predominant cell was the CD68-positive macrophage, followed by the T-lymphocyte. Cells immunolabeled with a polyclonal antibody to M. pneumoniae included perivascular to parenchymal macrophages/microglia, occasional oligodendrocytes, and neurons, particularly in brainstem. Affected neurons varied from morphologically normal to profoundly degenerate and necrotic. Ultrastructural study of the inferior olive confirmed the presence of 260-600 nm cell-wall-free microorganisms, consistent with mycoplasma, in perivascular cells and neurons. Foci of acute disseminated encephalomyelitis also were rarely identified. This case report confirms the postulated role of direct infection of brain by mycoplasma in acute childhood encephalitis, but also reveals a virus-like infection of central neurons. The pathogenesis of acute childhood encephalitis due to mycoplasma seems to be multifactorial.

[Microbiological diagnosis of mycoplasma infections]

The microbiological diagnosis of mycoplasma and ureaplasma infections has always been limited due to the fastidious growth of these microorganisms, as well as the lack of commercially prepared growth media, absence of rapid diagnostic procedures, and the clinical perception that these organisms are less significant in the infectious diseases setting. During the last few years, this situation has substantially improved due to the commercial availability of culture media, the development of rapid serological techniques, and, in particular, to the introduction of nucleic acid amplification assays, commercially available or "in-house" preparations. Despite the lack of proper standardisation and validation of the molecular and serological techniques, methodological advances have led to an increased detection of these microorganisms and, consequently, a greater appreciation of their clinical relevance.

Macrolides in the treatment of asthma

PURPOSE OF REVIEW

This review summarizes the importance of macrolide therapy in the treatment of asthma, discusses macrolide mechanisms of action, and outlines new clinical data supporting their use. The effects of macrolides on both the innate and adaptive immune responses are discussed.

RECENT FINDINGS

Subacute bacterial infection with both typical and atypical organisms contributes to poor asthma control. Identification of pathogens using polymerase chain reaction (PCR) and cultures from bronchoscopic samples directs antibiotic therapy and improves asthma control. PCR identification of Mycoplasma pneumoniae and Chlamydophila pneumoniae in asthmatics best identifies the macrolide responsive phenotype.

SUMMARY

Because of their effect on protein synthesis, macrolides have both antimicrobial and anti-inflammatory properties. Both mechanisms appear to be important in their clinical efficacy in treating a wide variety of pulmonary disorders, including asthma.

Colonization of paediatric lower respiratory tract with genital Mycoplasma species

BACKGROUND AND OBJECTIVE

Recently, much attention has been given to the possible role played by pathogens that colonize neonatal or paediatric airway and their potential involvement in chronic respiratory disease. The goal of the current study was to evaluate the prevalence of Mycoplasma organisms in the BAL fluid of paediatric patients suffering from a variety of chronic respiratory diseases to determine if there was any clear disease association with bacterial presence.

METHODS

We examined 319 paediatric BAL samples for the presence of M.genitalium, M.hominis, U.urealyticum, U.parvum and M.pneumoniae DNA with species-specific PCR.

RESULTS

Mycoplasma DNA was found in 32.6% (104/319) of patient samples; 10% (32/319) for M.pneumoniae, 8.8% for U.parvum, 2.8% for U.urealyticum; 4.7% for M.hominis and 9.1% for M.genitalium. There were no significant clinical and laboratory differences except serum IgE in asthmatics according to Mycoplasma colonization or not. Elevated levels of IgE were found more often in Mycoplasma DNA-negative patients than patients with bacterial DNA, 85/109 versus 24/109 respectively (P<0.0001). There was no difference in the frequency of Mycoplasmas between the asthmatics and the non-asthmatics; 30.6% (69/225) versus 37.2% (35/94) for Mycoplasma 16S DNA, and 8% versus 14.9% for M.pneumoniae, respectively.

CONCLUSIONS

Our data indicate that in addition to M.pneumoniae, urogenital Mycoplasma species may colonize the airway of patients with chronic respiratory diseases. There was, however, no association between chronic asthma diagnosis and Mycoplasma colonization in this study.

Multiple organ dysfunction syndrome associated with Mycoplasma pneumoniae infection

In this study, we report one case of a three-year-old boy infected with Mycoplasma pneumonia (MP) and presenting concomitant multiple organ damage of the heart, kidney, lung and liver, among others, together with a brief review for the diagnosis and treatment of MP infection with multiple organ dysfunction syndrome (MODS).

Eosinophilic Fasciitis associated with Mycoplasma arginini infection

Eosinophilic fasciitis (EF) with generalized sclerodermiform skin lesions developed over a 19-month period in a previously healthy 23-year-old man. Although we confirmed EF by skin histology and laboratory tests, the recurrent fevers and the clinical observation of sclerotic prepuce with urethritis indicated further bacteriological analysis by conventional microbiological and DNA-based tests. Urethra cultures were positive for an arginine-hydrolyzing mycoplasma and Ureaplasma urealyticum. The patient also had serum IgM antibodies to Mycoplasma pneumoniae using enzyme-linked immunosorbent assay (ELISA)-based qualitative detection. Mycoplasma arginini was isolated from two independent venous blood serum samples and was identified by conventional microbiological tests and sequencing of the 16S rRNA and rpoB genes (GenBank sequence accession numbers HM179555 and HM179556, respectively). M. arginini genomic DNA also was detected by species-specific PCR in the skin lesion biopsy sample. Treatment with corticosteroids and long-term courses of selected antibiotics led to remission of skin symptoms and normalization of laboratory values. This report provides the first evidence of EF associated with mycoplasma infection and the second report of human infection with M. arginini and therefore suggests that this mycoplasma infection might have contributed to the pathogenesis of the disease.

Antibiotic sensitivity of 40 Mycoplasma pneumoniae isolates and molecular analysis of macrolide-resistant isolates from Beijing, China

MICs of eight antibiotics were detected with 40 Chinese Mycoplasma pneumoniae isolates. Thirty-eight isolates (95%) were macrolide resistant. Each macrolide-resistant isolate harbored an A2063G or A2064G point mutation in the 23S rRNA gene. All 40 isolates (100%) were type I strains, but they might have originated from different clones.

Amplification of 16S rDNA by nested PCR for measurement of Mycoplasma pneumoniae DNA over time: clinical application

Mycoplasma pneumoniae (MP) is the most common atypical pathogen that causes respiratory infections in children. Such infections are typically treated by macrolide antibiotics, but the duration of treatment is variable. In this study, we used nested PCR to amplify the 16S rDNA (16S rRNA gene) of MP at different stages of MP pneumonia (MPP) in 100 children who were admitted for lower respiratory tract infections and diagnosed with MPP. Our results indicate that the median duration of MP-DNA positivity was 5 weeks, and 78 % of cases tested positive for 3-6 weeks. Patients with severe disease were positive for MP-DNA for a significantly longer time (median of 6 weeks) than those with mild disease (median of 4 weeks). Thirty-one patients with severe disease who received intravenous immunoglobulin were MP-DNA positive for significantly less time than patients with severe disease who did not receive this treatment. The duration of MP-DNA positivity was prolonged when MP antibody levels were high and treatment was started at a later stage. Therefore, nested PCR can be used for early diagnosis of MP and the duration of MP-DNA reflects the clinical stage of MPP. Early treatment of MPP and the administration of intravenous immunoglobulin during the acute phase of severe MPP shorten the duration of MP-DNA positivity.

Mycoplasma pneumoniae: susceptibility and resistance to antibiotics

Mycoplasma pneumoniae is a pathogenic mycoplasma responsible for respiratory tract infections in humans, which occurs worldwide in children and adults. This article focuses on its antibiotic susceptibility profile and on the development of acquired resistance in this microorganism. The lack of a cell wall in mycoplasmas makes them intrinsically resistant to β-lactams and to all antimicrobials that target the cell wall. M. pneumoniae is susceptible to macrolides and related antibiotics, tetracyclines and fluoroquinolones. Macrolides and related antibiotics are the first-line treatment for respiratory infections caused by M. pneumoniae. However, strains with acquired resistance to macrolides have recently emerged worldwide and have been spreading in Europe, USA and A sia especially, with more than 90% of Chinese isolates resistant to erythromycin and azithromycin. This acquired resistance can be detected by PCR methods directly from respiratory specimens and is related to 23S rRNA mutations.

Clinical SERS: are we there yet?

Surface Enhanced Raman Spectroscopy or SERS has witnessed many successes over the past 3 decades, owing particularly to its simplicity of use as well as its highly-multiplexing capability. This article provides an overview of SERS and its applicability in the field of bio-medicine. We will preview recent developments in SERS substrate designs, and the various sensing technologies that are based on the SERS phenomenon. An overview of the clinical applications of SERS is also included. Finally, we provide an opinion on the future trends of this unique spectroscopic technique.

Mycoplasmal cerebral vasculopathy in a lymphoma patient: presumptive evidence of Mycoplasma pneumoniae microvascular endothelial cell invasion in a brain biopsy

A 73-year-old man had episodic encephalopathy, ataxia and neuropathy. Symptoms largely resolved but adenopathy later lead to the diagnosis of a low-grade follicular lymphoma. The neurological symptoms soon recurred with new pontine calcifications identified by computed tomography. Brain biopsy revealed microvascular endothelial cell nuclear changes. Electron microscopy identified small polymorphic bacteria without a cell wall and with terminal and attachment organelles within endothelial cells and clustered in some microvascular lumina. Immunostaining was positive for Mycoplasma pneumoniae and convalescent serum enzyme immunoassay was positive for M. pneumoniae IgG. The patient again recovered and he was neurologically stable 33 months after the initial episode. The ultrastructural findings of the bacterial cells are distinctive of some mycoplasmal species when compared to other small bacteria. Mycoplasma-like organisms are reported in four autopsied patients who had chronic encephalopathy, movement disorders, and some of the same light- and electron-microscopic findings in the brain as our patient. Direct neuroinvasion by Mycoplasma species has been suggested, while anatomic observations in our patient and in the four autopsy cases show microvascular invasion but not parenchymal invasion. Most mycoplasmal encephalitis may be immune-mediated. The frequency of neurovascular invasion is not known. It may be rare and it may persist.

Mycoplasma pneumoniae: Innocent Bystander or a True Cause of Central Nervous System Disease?

The consistency with which Mycoplasma pneumoniae has been implicated as a cause of encephalitis, and the increased incidence of central nervous system (CNS) disease observed during M. pneumoniae respiratory outbreaks, support the role of M. pneumoniae as a CNS pathogen. Three pathophysiologic mechanisms have been proposed: direct infection, autoimmunity, and vascular occlusion. Recent evidence demonstrating the organism's ability to survive intracellularly, presence of its DNA in the serum of individuals with acute encephalitis, case reports in which the organism is detected in brain parenchyma or cerebrospinal fluid (CSF), and animal data demonstrating CNS invasion by several Mycoplasma species support the contention that M. pneumoniae is capable of direct infection of the CNS. Because of limitations of current serologic assays and difficulty in interpreting the significance of positive polymerase chain reaction results in regard to acuity of infection and viability of the organism, the diagnosis of M. pneumoniae-associated CNS disease should be based on a combination of positive tests and exclusion of alternative diagnoses.

Stevens-Johnson syndrome in a boy with macrolide-resistant Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae is a highly specialized parasitic bacterium that is a significant cause of community-acquired pneumonia in children. Although most such respiratory infections are mild, a minor percentage of patients require hospitalization and, occasionally, intensive treatment for respiratory failure. A variety of extrapulmonary sequelae of M pneumoniae infections have been described, including Stevens-Johnson syndrome. Macrolide resistance in M pneumoniae has developed rapidly in Asia, particularly in China, over the past decade and is now appearing in the United States. Emerging resistance to macrolides creates a therapeutic conundrum, particularly for pediatricians caring for young children in whom absolute or relative contraindications exist for the use of tetracyclines or fluoroquinolones, the 2 other main classes of drugs shown to be efficacious for M pneumoniae. We describe here the case of a child with a prolonged febrile illness associated with Stevens-Johnson-like mucocutaneous involvement who was found to have a respiratory infection with macrolide-resistant M pneumoniae.

Lower respiratory tract infections in cats: reaching beyond empirical therapy

PRACTICAL RELEVANCE

Lower respiratory tract infections (LRTIs) in cats can be due to bacteria, parasites, fungi and viruses. This review details the practical investigation of these infections and highlights specific therapy where possible. The aim is to avoid the all-too-frequent temptation in practice to treat cats with lower respiratory tract signs empirically for feline bronchial disease (FBD)/asthma. This is potentially hazardous as immunosuppressive therapy for FBD/asthma could exacerbate disease due to a LRTI. Empirical treatment of suspected LRTI is also difficult to recommend given the wide range of potential pathogens.

CLINICAL CHALLENGES

Making a clinical ante-mortem diagnosis of LRTI in a cat can be challenging. Consistent historical, clinical, haematological and radiographic abnormalities are often lacking and findings may be non-specific. Astute clinical acumen, thorough investigation and high quality laboratory analysis are usually required for a diagnosis. Bronchoalveolar lavage, if feasible, and tests for lungworm should be routine in cats with lower respiratory tract signs. Lung fine needle aspiration may be useful in cases of diffuse or nodular pulmonary disease. Histopathology is rarely employed in ante-mortem investigations.

EVIDENCE BASE

The authors have reviewed a substantial body of literature to provide information on many of the reported bacterial, parasitic, fungal and viral pathogens, including some that occur in Asia. Attention has been given to specific therapy for each pathogen, with evidence-based comments when there is a deviation from routine recommendations.

Prevalence of Mycoplasma pneumoniae-associated respiratory tract infections in hospitalized children: results of a 4-year prospective study in Tunis

Specific microbiologic, molecular, and serologic assays are hardly available in Tunis to confirm a suspected infection of Mycoplasma pneumoniae (MP). These diagnosis methods were used for the first time in a Tunisian prospective study to estimate the prevalence of MP infection in children and to evaluate their usefulness for diagnosis. A total of 540 children hospitalized in Tunis for lower respiratory tract infections (LRTIs) between 2005 and 2009 and 580 clinical specimens were investigated for the presence of MP by culture and by end-point polymerase chain reaction (PCR) targeting the P1 and the 16S rRNA genes. Real-time PCR was also used for MP detection on 158 respiratory samples. A total of 525 serum samples were tested for detection of MP-specific IgM and IgG. The P1 adhesin type and the antibiotic susceptibility testing were determined for the 9 clinical strains isolated during the study period. MP was detected in 33 (5.7%) clinical samples. Specific MP seropositivity was confirmed in 54 serum samples (10.3%), among which 19 (3.6%) were indicative of acute MP infection. MP infection was confirmed in 39 (7.2%) patients: 24 positive by PCR and/or culture, 10 serologically positive only, and 5 confirmed positive by both methods. MP infections occurred throughout the year with a slight decrease in autumn. The 9 MP isolates were susceptible to erythromycin, tetracycline, and ciprofloxacin, and all belonged to type I. The prevalence of MP infection in children with LRTI was 7.2% between 2005 and 2009, in Tunisia. Combination of direct detection and serology was required to enhance the clinical sensitivity of MP detection in clinical specimens.

Domain analysis of protein P30 in Mycoplasma pneumoniae cytadherence and gliding motility

The cell wall-less prokaryote Mycoplasma pneumoniae causes bronchitis and atypical pneumonia in humans. Mycoplasma attachment and gliding motility are required for colonization of the respiratory epithelium and are mediated largely by a differentiated terminal organelle. P30 is a membrane protein at the distal end of the terminal organelle and is required for cytadherence and gliding motility, but little is known about the functional role of its specific domains. In the current study, domain deletion and substitution derivatives of P30 were engineered and introduced into a P30 null mutant by transposon delivery to assess their ability to rescue P30 function. Domain deletions involving the extracellular region of P30 severely impacted protein stability and adherence and gliding function, as well as the capacity to stabilize terminal organelle protein P65. Amino acid substitutions in the transmembrane domain revealed specific residues uniquely required for P30 stability and function, perhaps to establish correct topography in the membrane for effective alignment with binding partners. Deletions within the predicted cytoplasmic domain did not affect P30 localization or its capacity to stabilize P65 but markedly impaired gliding motility and cytadherence. The larger of two cytoplasmic domain deletions also appeared to remove the P30 signal peptide processing site, suggesting a larger leader peptide than expected. We propose that the P30 cytoplasmic domain may be required to link P30 to the terminal organelle core, to enable the P30 extracellular domain to achieve a functional conformation, or perhaps both.

Effects of atypical infections with Mycoplasma and Chlamydia on asthma

Mycoplasma pneumoniae and Chlamydophila pneumoniae are atypical bacteria that are frequently found in patients with asthma. A definitive diagnosis of infection is often difficult to obtain because of limitations with sampling and detection. Numerous animal studies have outlined mechanisms by which these infections may promote allergic lung inflammation and airway remodeling. In addition, there is mounting evidence from human studies suggesting that atypical bacterial infections contribute to asthma exacerbations, chronic asthma, and disease severity. The role of antimicrobials directed against atypical bacteria in asthma is still under investigation.

Detection of Mycoplasma pneumoniae in simulated and true clinical throat swab specimens by nanorod array-surface-enhanced Raman spectroscopy

The prokaryote Mycoplasma pneumoniae is a major cause of respiratory disease in humans, accounting for 20% of all community-acquired pneumonia and the leading cause of pneumonia in older children and young adults. The limitations of existing options for mycoplasma diagnosis highlight a critical need for a new detection platform with high sensitivity, specificity, and expediency. Here we evaluated silver nanorod arrays (NA) as a biosensing platform for detection and differentiation of M. pneumoniae in culture and in spiked and true clinical throat swab samples by surface-enhanced Raman spectroscopy (SERS). Three M. pneumoniae strains were reproducibly differentiated by NA-SERS with 95%-100% specificity and 94-100% sensitivity, and with a lower detection limit exceeding standard PCR. Analysis of throat swab samples spiked with M. pneumoniae yielded detection in a complex, clinically relevant background with >90% accuracy and high sensitivity. In addition, NA-SERS correctly classified with >97% accuracy, ten true clinical throat swab samples previously established by real-time PCR and culture to be positive or negative for M. pneumoniae. Our findings suggest that the unique biochemical specificity of Raman spectroscopy, combined with reproducible spectral enhancement by silver NA, holds great promise as a superior platform for rapid and sensitive detection and identification of M. pneumoniae, with potential for point-of-care application.

Characterization of macrolide resistance in Mycoplasma pneumoniae isolated from children in Shanghai, China

One hundred Mycoplasma pneumoniae strains were isolated from pediatric patients from March 2008 to July 2009. Of 100 isolates, 90 (90%) were resistant to erythromycin (MICs >128 microg/mL for 88 strains and 64 microg/mL for 2 strains), azithromycin, and clarithromycin. Fluoroquinolones and tetracyclines maintain good activities against clinical M. pneumoniae isolates. Of 90 macrolide-resistant M. pneumoniae strains, 88 (98%) harbored an A-to-G transition mutation at position 2063 in 23S rRNA genes, and the remaining 2 showed either A2064G or A2063T mutation; the latter point mutation is newly discovered and reported. Ninety-three (93%) clinical isolates were classified into the P1 gene restriction fragment length polymorphism (RFLP) type I, and 7 (7%) were type II.

Loss and gain of GroEL in the Mollicutes

GroEL is a chaperone thought of as essential for bacterial life. However, some species of Mollicutes are missing GroEL. We use phylogenetic analysis to show that the presence of GroEL is polyphyletic among the Mollicutes, and that there is evidence for lateral gene transfer of GroEL to Mycoplasma penetrans from the Proteobacteria. Furthermore, we propose that the presence of GroEL in Mycoplasma may be required for invasion of host tissue, suggesting that GroEL may act as an adhesin-invasin.

Nested PCR-linked capillary electrophoresis and single-strand conformation polymorphisms for detection of macrolide-resistant Mycoplasma pneumoniae in Beijing, China

Mycoplasma pneumoniae is usually susceptible to macrolides, but macrolide-resistant strains have been found frequently in recent years. Mutations in domain V of the 23S rRNA gene of M. pneumoniae interfere with the binding of macrolides to rRNA and mediate macrolide resistance. In this study, we developed a rapid and inexpensive method that combines nested PCR (nPCR), single-strand conformation polymorphisms (SSCPs), and capillary electrophoresis (CE) to detect macrolide-resistant mutants directly from throat swabs. nPCR was used to specifically amplify M. pneumoniae 23S rRNA gene fragments containing mutations, and amplicons were analyzed by CE-SSCP for macrolide resistance mutations, with results confirmed by sequencing. From January to December 2009, 665 throat swabs were collected in Beijing, China, yielding 110 samples that tested positive for M. pneumoniae by nPCR and serological testing. We randomly selected 64 positive throat swabs for CE-SSCP analysis. The A2063G mutation was found in 57 samples, and a coexisting T2611C mutation was identified in 1 sample. An A2063T mutation was identified in 1 sample. The total mutation rate was 91%. All mutant samples identified by nPCR-CE-SSCP were sequenced. The nPCR-CE-SSCP method could identify macrolide-resistant mutants directly from clinical samples. This is the first report of an nPCR-CE-SSCP assay for the detection of dominant mutations that confer macrolide resistance on M. pneumoniae. This approach would allow clinicians to choose appropriate therapy rapidly and could be used as a screening method for genetic mutations related to antibiotic resistance.

The role of Mycoplasma in upper respiratory infections

Mycoplasma pneumoniae is a common cause of upper and lower respiratory tract infections. Pneumonia is the most clinically important manifestation, but tracheobronchitis and various nonspecific upper respiratory tract symptoms are more typically seen in clinical settings. M. pneumoniae can cause pharyngitis with or without concomitant lower respiratory tract involvement, but it is less commonly detected in other upper respiratory conditions such as otitis media, sinusitis, and the common cold. A variety of methods exist for laboratory diagnosis of M. pneumoniae infection, including culture, serology, and the polymerase chain reaction assay, but each has limitations. This article provides a summary of recent studies that have evaluated the role of M. pneumoniae in upper respiratory tract infections; a brief discussion of its cell biology, pathogenic mechanisms, and epidemiology; and recommendations for laboratory diagnosis and management.

[Asthma and Mycoplasma pneumoniae]

INTRODUCTION

A growing body of basic and clinical science implicates Mycoplasma pneumonia in asthma, but its exact contribution to asthma development, exacerbation and persistence is as yet unclear.

STATE OF THE ART

M. pneumoniae infection, with the induction of bronchial hyperresponsiveness, seems to be a precipitating factor for asthma development in predisposed subjects. M. pneumoniae has been seen both in acute exacerbation (18-20%) and in chronically infected adults with stable asthma, where it may be enhancing chronic airway inflammation.

PERSPECTIVES

If M. pneumoniae plays a role in the development or progression of asthma, its eradication might influence the clinical course of the disease and improve symptoms. Macrolide treatment, with antimicrobial and anti-inflammatory properties, could have a place in the management of asthma, especially steroid-dependent asthma.

CONCLUSIONS

M. pneumoniae infection seems to be important in asthma pathogenesis and the clinical course of the disease. Difficulty in detecting the pathogen complicates investigations. Ongoing research will further determine the place of macrolide antibiotics in asthma management.

Mycoplasma pneumoniae and Chlamydia pneumoniae seropositivity in patients with age-related macular degeneration

Background

To determine a possible relation between Mycoplasma pneumoniae (MP) or Chlamidia pneumoniae (CP) seropositivity and age-related macular degeneration (AMD).

Methods

Sixty patients (20 wet AMD, 20 dry AMD and 20 non-AMD controls) were included in the study. Serum samples were collected for analysis of IgM and IgG antibody seropositivity for CP and MP by enzyme-linked immunosorbent assay (ELISA). Comparison of the distribution of seropositivity of these antibodies among patients with wet and dry AMD, and controls was performed. A prospective comparative clinical trial was applied.

Results

There was no major difference in the distribution of IgM and IgG seropositivity to CP and MP in patients with wet and dry AMD, and in controls (p > 0.05).

Conclusions

We found no significant association between MP as well as CP antibody titers and AMD. It seems that MP or CP infection is not a risk factor for AMD.

Keywords

Mycoplasma pneumoniae; Chlamydia pneumoniae; Age-related macular degeneration; Serology

Identification of P1 variants of Mycoplasma pneumoniae by use of high-resolution melt analysis

Mycoplasma pneumoniae is a leading cause of community-acquired pneumonia. Although two genetically distinct types of M. pneumoniae are known, variants of each also exist. We used a real-time PCR high-resolution melt genotyping assay to identify clinical variants which may provide greater insight into the genetic distribution of M. pneumoniae strains.

Antimicrobial susceptibility of Mycoplasma pneumoniae isolates and molecular analysis of macrolide-resistant strains from Shanghai, China

Fifty-three Mycoplasma pneumoniae strains were isolated from pediatric patients in Shanghai, China, from October 2005 to February 2008. Of 53 clinical isolates, 44 (83%) were resistant to erythromycin (MICs of >128 microg/ml for all 44 strains), azithromycin, and clarithromycin. All macrolide-resistant M. pneumoniae strains harbored an A-to-G transition mutation at position 2063 in 23S rRNA genes. Forty-five (85%) clinical isolates were classified into the P1 gene restriction fragment length polymorphism type I, and six (11%) were type II.