Ureaplasma infections: update on epidemiology, antimicrobial resistance, and pathogenesis

Human Ureaplasma species are being increasingly recognized as opportunistic pathogens in human genitourinary tract infections, infertility, adverse pregnancy, neonatal morbidities, and other adult invasive infections. Although some general reviews have focused on the detection and clinical manifestations of Ureaplasma spp., the molecular epidemiology, antimicrobial resistance, and pathogenesis of Ureaplasma spp. have not been adequately explained. The purpose of this review is to offer valuable insights into the current understanding and future research perspectives of the molecular epidemiology, antimicrobial resistance, and pathogenesis of human Ureaplasma infections. This review summarizes the conventional culture and detection methods and the latest molecular identification technologies for Ureaplasma spp. We also reviewed the global prevalence and mechanisms of antibiotic resistance for Ureaplasma spp. Aside from regular antibiotics, novel antibiotics with outstanding in vitro antimicrobial activity against Ureaplasma spp. are described. Furthermore, we discussed the pathogenic mechanisms of Ureaplasma spp., including adhesion, proinflammatory effects, cytotoxicity, and immune escape effects, from the perspectives of pathology, related molecules, and genetics.

Mollicutes-related infections in thoracic surgery including lung and heart transplantation: A systematic review

BACKGROUND

Urogenital Mollicutes, that is, Mycoplasma hominis and Ureaplasma spp., can colonize the urogenital tract. While urogenital colonization is frequent, infections are rare but should not be missed. Furthermore, extragenital infections are even rarer. Over the past years, they have been increasingly documented as a cause of hyperammonemia syndrome (HS) and post-surgical infections. We review the literature on studies focused on post-surgical infections and HS involving urogenital Mollicutes after thoracic surgery including lung (LTR) and heart (HTR) transplantation.

METHODS

A systematic review was performed by searching PubMed/Medline case reports, case series, cohort studies, and clinical trials. Cases of infections and HS by urogenital Mollicutes after HTR and LTR transplantations were reported.

RESULTS

Overall, urogenital Mollicutes were associated with 15 HS, 31 infections in HTR and LTR, and 18 post-thoracic surgical infections in another context. Post-surgical infections were reported in all contexts. They were mainly due to M hominis, the only species that could cultivate on standard enriched agar forming pinpoint colonies after 3-5 days of incubation. Microbiologists should be prompted to pinpoint colonies even if the examination of Gram-staining is negative. The patients' management required surgical treatment and antimicrobials, almost always tetracyclines and/or fluoroquinolones. Conversely, HS occurred almost exclusively in bilateral LTR and is more likely due to Ureaplasma spp. As Ureaplasma spp. do not cultivate on standard media, the microbiological diagnosis was performed using molecular methods.

CONCLUSIONS

Infections involving urogenital Mollicute should be considered in LTR with HS. The overall rate of mortality is high and might be due in part to delay in etiologic diagnosis. Post-surgical infections were reported in all contexts. The route of contamination with Mollicutes remains unknown in HTR and non-transplant surgery, but evidence of transmission from donors has been documented for LTR.

Fatal multiple organ dysfunction caused by commensal bacteria of urogenital tract infection in adult lung transplant recipients: two case reports

BACKGROUND

Infection following lung transplantation has been the focus of clinical concerns. The colonization rate of commensal bacteria of the urogenital tract, including Mycoplasma hominis, Ureaplasma urealyticum (UU), and herpes simplex virus type-2 (HSV-2), is high, which may cause secondary infection after transplantation.

CASE PRESENTATION

Twenty-three-year-old and 67-year-old women underwent lung transplantation for different causes. Shortly after the operation, they developed perineal skin ulcers, hypoxia, and intractable epilepsy. Subsequent computed tomography (CT) of the chest showed lung consolidation, and cranial CT showed shallowing sulci and gyri. UU and HSV-2 were detected in bronchoalveolar lavage fluid by next-generation sequencing, and HSV-2 was shown in the cerebrospinal fluid of both patients. Despite active treatment, both suffered irreversible brain function damage within 72 h of the seizure.

CONCLUSIONS

Clinicians should know that commensal bacteria of urogenital tract infections can lead to fatal multiple organ dysfunction after lung transplantation.

Brain abscess with Ureaplasma parvum in a patient with granulomatosis with polyangiitis

PURPOSE

Ureaplasma species are associated with urogenital infections, infertility and adverse pregnancy outcomes as well as neonatal infections. Involvement of the central nervous system in adults is extremely rare. We report an unusual case of a brain abscess secondary to otitis media with Ureaplasma parvum in a patient with granulomatosis with polyangiitis (GPA).

METHODS

Imaging and laboratory findings, treatment decisions, and outcome of this case are explicated.

RESULTS

A young adult with GPA presented with progredient earache after ambulant diagnosis of otitis media. Despite different courses of broad-spectrum antibiotic therapy, she developed meningoencephalitis due to mastoiditis following temporal abscess formation. Mastoidectomy and neurosurgical abscess removal were performed. Standard cultures of cerebrospinal fluid, blood and intracranial abscess material, as well as polymerase chain reaction (PCR) for common bacterial and viral meningitis pathogens remained negative. Only eubacterial PCR of intracranial abscess material returned positive for Ureaplasma parvum. The patient finally improved under antibiotic therapy with moxifloxacin and doxycycline.

CONCLUSION

Ureaplasma species are rare causative pathogens in immunocompromised patients. They should be considered in patients with humoral immunodeficiencies with culture-negative infections failing standard therapy. Eubacterial PCR should be performed in early states of infection in these patients for immediate diagnosis and initiation of appropriate treatment to prevent adverse outcomes.

Ureaplasma parvum meningitis following atypical choroid plexus papilloma resection in an adult patient: a case report and literature review

Background

While Ureaplasma parvum has previously been linked to the incidence of chorioamnionitis, abortion, premature birth, and perinatal complications, there have only been rare reports of invasive infections of the central nervous system (CNS) in adults. Owing to its atypical presentation and the fact that it will yield sterile cultures using conventional techniques, diagnosing U. parvum meningitis can be challenging.

Case presentation

We describe a case of U. parvum meningitis detected in an adult patient following surgical brain tumor ablation. After operation, the patient experienced epilepsy, meningeal irritation, and fever with unconsciousness. Cerebrospinal fluid (CSF) analysis showed leukocytosis (484 * 10⁶ /L), elevated protein levels (1.92 g/L), and decreased glucose concentrations (0.02 mmol/L). Evidence suggested that the patient was suffering from bacterial meningitis. However, no bacterial pathogens in either CSF or blood were detected by routine culture or serology. The symptoms did not improve with empirical antibiotics. Therefore, we performed metagenomic next-generation sequencing (mNGS) to identify the etiology of the meningitis. Ureaplasma parvum was detected by mNGS in CSF samples. To the best of our knowledge, this case is the first reported instance of U. parvum meningitis in an adult patient in Asian. After diagnosis, the patient underwent successful moxifloxacin treatment and recovered without complications.

Conclusions

As mNGS strategies can enable the simultaneous detection of a diverse array of microbes in a single analysis, they may represent a valuable means of diagnosing the pathogens responsible for CNS infections and other clinical conditions with atypical presentations.

[Clinical implications of the genus Mycoplasma]

Dentro del género Mycoplasma, las especies que tradicionalmente se han relacionado con cuadros infecciosos han sido principalmente M. pneumoniae, M. genitalium, M. hominis o U. urealyticum. Sin embargo, existen otras muchas que están implicadas y, que muchas veces, son desconocidas para los profesionales sanitarios. El objetivo de esta revisión es identificar todas las especies del género Mycoplasma que se han aislado en el hombre y determinar su participación en la patología infecciosa humana.

Hyperammonemia by Ureaplasma urealyticum Pneumonia after Lung Transplantation

Ureaplasma urealyticum is a commensal of the female genital tract and can be detected as a pathogen in urethritis and vaginitis. Its importance as a respiratory pathogen beyond the field of neonatology remains controversial. We report a case of Ureaplasma-pneumonia in a recently lung-transplanted patient, with hyperammonemic syndrome.

The 51-year-old lung-transplanted female was admitted to the intensive care unit with new-onset reduction of her mental state due to hyperammonemia. A diagnostic bronchoscopy showed purulent bronchitis and multiple superficial ulcerations of the bronchial mucosa. The DNA-PCR from bronchoalveolar lavage confirmed the presence of Ureaplasma urealyticum in low concentration (about 5 * 10⁴ copies/ml), which was interpreted as evidence of infection and treated with Doxycycline intravenously. Ureaplasma was also identified by DNA-PCR in the biopsy specimens of the inflammatory enlarged mediastinal lymph nodes. Bilateral pleural effusions were found to be transudative and culturally sterile.

Ureaplasma-pneumonia can cause fatal hyperammonemia in lung-transplant patients and should be considered in the differential diagnosis of every unclear hyperammonemia with normal liver function. The early identification and treatment of the infection leads to clinical and biochemical resolution.

Ureaplasma parvum ventriculitis related to surgery and ventricular peritoneal drainage

Ureaplasma spp. usually causes genitourinary infections; few reports in the literature describe extragenital infections, usually in immunocompromised patients. We present a case of Ureaplasma parvum ventriculitis in an immunocompetent patient related to ventriculoperitoneal drainage and surgery. Ureaplasma parvum was detected with broad range 16S rRNA PCR and cultured on A8 agar.

[Mycoplasma hominis bacteremia. An underestimated etiological agent]

Mycoplasma hominis is a fastidious bacterium, which usually colonizes the lower urogenital tract and may cause systemic infections in neonates and genital infections in adults. It can also be the cause of serious extra-genital infections, mainly in immunosuppressed or predisposed subjects.

CASE PRESENTATION

We describe a case of bacteremia caused by M. hominis in a previously healthy woman after uterine curettage due to incomplete abortion. M. hominis could be an underestimated cause of bacteremia in immunocompetent patients. Mycoplasma organisms have fastidious growth requirements, are often difficult to culture on a cell-free medium and have no cell wall. The conventional method for detection may fail. This is the first report of M. hominis isolation from a positive automated blood culture (BD BACTEC, USA).

Atypical Wound Pathogens

BACKGROUND

Atypical wound pathogens may be so described because they are uncommon pathogens of soft tissue among human beings, or because they may be fastidious and difficult to recover/isolate in the laboratory.

METHODS

A review of pertinent English-language literature was performed.

RESULTS

These wound pathogens are a diverse lot, including aerobic and anaerobic gram-positive and gram-negative bacilli, non-tuberculous mycobacteria, and bacteria that cannot be characterized conventionally because they lack a cell wall (the Mycoplasmataceae). They are diverse with respect to their virulence, but many are opportunistic pathogens.

CONCLUSIONS

Among these atypical pathogens, clinical reports are most common of wound infections caused by Mycoplasma/Ureaplasma (sometimes as co-infecting agents), and the so-called rapidly growing non-tuberculous mycobacteria (Runyon Type IV; e.g., M. chelonae).

Mycoplasma hominis Induces Mediastinitis after a Tonsillar Abscess

Mycoplasma hominis is commonly involved in genitourinary tract infections. We report a 59-year-old man who developed a M. hominis-associated mediastinitis following acute tonsillar infection.

Mycoplasma hominis, a Rare but True Cause of Infective Endocarditis

Mycoplasma spp. are rarely recognized agents of infective endocarditis. We report a case of Mycoplasma hominis prosthetic valve endocarditis diagnosed by 16S ribosomal DNA (rDNA) PCR and culture of valves in a 74-year-old man. We reviewed the literature and found only 8 other cases reported.

A new case of Mycoplasma hominis mediastinitis and sternal osteitis after cardiac surgery

We report a case of nosocomial mediastinitis and sternal osteitis due to M. hominis after open-heart surgery in an immuno-competent patient. This infection has been diagnosed by incubating the culture media for an extended period of time, and sequencing 16S rDNA directly from the clinical samples.

Molecular mechanism of fluoroquinolones resistance in Mycoplasma hominis clinical isolates

To evaluate the molecular mechanism of fluoroquinolones resistance in Mycoplasma hominis (MH) clinical strains isolated from urogenital specimens. 15 MH clinical isolates with different phenotypes of resistance to fluoroquinolones antibiotics were screened for mutations in the quinolone resistance-determining regions (QRDRs) of DNA gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE) in comparison with the reference strain PG21, which is susceptible to fluoroquinolones antibiotics. 15 MH isolates with three kinds of quinolone resistance phenotypes were obtained. Thirteen out of these quinolone-resistant isolates were found to carry nucleotide substitutions in either gyrA or parC. There were no alterations in gyrB and no mutations were found in the isolates with a phenotype of resistance to Ofloxacin (OFX), intermediate resistant to Levofloxacin (LVX) and Sparfloxacin (SFX), and those susceptible to all three tested antibiotics. The molecular mechanism of fluoroquinolone resistance in clinical isolates of MH was reported in this study. The single amino acid mutation in ParC of MH may relate to the resistance to OFX and LVX and the high-level resistance to fluoroquinolones for MH is likely associated with mutations in both DNA gyrase and the ParC subunit of topoisomerase IV.

Vacuum-assisted closure (VAC)-Instill(®) with continuous irrigation for the treatment of Mycoplasma hominis mediastinitis

A 56-year-old patient who underwent ascending aorta replacement postoperatively developed mediastinitis with atypical Mycoplasma hominis. We present the first successful treatment of M. hominis mediastinitis after cardiac surgery with vacuum-assisted closure (VAC)-Instill(®) therapy combined with dilute antiseptic irrigation for bacterial eradication.

Brain abscess caused by Ureaplasma urealyticum in an adult patient

Ureaplasma urealyticum is a fastidious bacterium usually residing in the female genitourinary tract. We present an exceedingly complicated case of a brain abscess secondary to mastoiditis by U. urealyticum in an adult hypogammaglobulinemic patient after rituximab treatment 3 years earlier.

In vitro antimicrobial profile of Ureaplasma urealyticum from genital tract of childbearing-aged women in Northern and Southern Italy

Ureaplasma urealyticum is an opportunistic pathogen during pregnancy and in newborns. Other clinical problems related to U. urealyticum infections are: no susceptibility to cell wall-active drugs, limits of antibiotic treatment in pregnancy, and spread of antimicrobial resistance. In addition, the results of antimicrobial susceptibility against U. urealyticum from various countries are few and controversial. The antimicrobial susceptibility of U. urealyticum, isolated from cervical swabs and collected from outpatient childbearing-aged women in Italy from 2009 to 2012, was performed against fluoroquinolones, macrolides, streptogramin and tetracyclines, using an available biochemical commercial kit and a specific solid culture medium, to improve the therapeutic management of these pathogenic agents. Ureaplasma urealyticum was detected in 49.4% of samples, but significant bacterial load was revealed in 29.8%. In vitro tetracyclines showed the best activity against U. urealyticum, followed by streptogramin, macrolides, and fluoroquinolones.

Cluster or coincidence? An unusual cause of surgical site infections in adult trauma patients

Mycoplasma hominis is a bacteria that colonizes and infects the genitourinary tract; extragenital infections are not common. Three surgical site infections because of M hominis in immunocompetent adult trauma patients were detected at our facility in a 6-month time period. We investigated this case series and hypothesize transmission based on common exposures.

Mycoplasma hominis necrotizing pleuropneumonia in a previously healthy adolescent

Background

Mycoplasma hominis is a fastidious micro-organism causing systemic infections in the neonate and genital infections in the adult. It can also be the cause of serious extra-genital infections, mainly in immunosuppressed or predisposed subjects.

Case Presentation

We describe a case of severe pneumonia and pericarditis due to Mycoplasma hominis in a previously healthy adolescent who did not respond to initial therapy.

Conclusions

Mycoplasma hominis could be an underestimated cause of severe pneumonia in immunocompetent patients and should be particularly suspected in those not responding to standard therapy.

A deep sternal wound infection caused by Ureaplasma urealyticum

Ureaplasma species are usually associated with infection of the urogenital tract. An unusual case of a sternal wound infection caused by Ureaplasma urealyticum in a 41-year-old male after aortic valve replacement is described.

Fatal outcome of a disseminated dual infection with drug-resistant Mycoplasma hominis and Ureaplasma parvum originating from a septic arthritis in an immunocompromised patient

Mycoplasma hominis and Ureaplasma parvum are rare causes of severe and fatal infections. The diagnosis of infection with mycoplasma is dependent on clinical suspicion and microbiological diagnosis, and often relies on molecular methods that do not readily detect antibiotic resistance. This may be of increasing importance as illustrated in the case below.

Evaluation of Mycoplasma inactivation during production of biologics: egg-based viral vaccines as a model

Although mycoplasmas are generally considered to be harmless commensals, some mycoplasma species are able to cause infections in pediatric, geriatric, or immunocompromised patients. Thus, accidental contamination of biologics with mycoplasmas represents a potential risk for the health of individuals who receive cell-derived biological and pharmaceutical products. To assess the efficiency of inactivation of mycoplasmas by the agents used in the manufacture of egg-derived influenza vaccines, we carried out a series of experiments aimed at monitoring the viability of mycoplasmas spiked into both chicken allantoic fluid and protein-rich microbiological media and then treated with beta-propiolactone, formalin, cetyltrimethylammonium bromide, Triton X-100, and sodium deoxycholate, which are agents that are commonly used for virus inactivation and disruption of viral particles during influenza vaccine production. Twenty-two mycoplasma species (with one to four strains of each species) were exposed to these inactivating agents at different concentrations. The most efficient inactivation of the mycoplasmas evaluated was observed with either 0.5% Triton X-100 or 0.5% sodium deoxycholate. Cetyltrimethylammonium bromide at concentrations of >or=0.08% was also able to rapidly inactivate (in less than 30 min) all mycoplasmas tested. In contrast, negligible reductions in mycoplasma titers were observed with 0.0125 to 0.025% formaldehyde. However, increasing the concentration of formaldehyde to 0.1 to 0.2% improved the mycoplasmacidal effect. Incubation of mycoplasmas with 0.1% beta-propiolactone for 1 to 24 h had a marked mycoplasmacidal effect. A comparison of the mycoplasma inactivation profiles showed that strains of selected species (Mycoplasma synoviae, Mycoplasma gallisepticum, Mycoplasma orale, Mycoplasma pneumoniae, and Acholeplasma laidlawii) represent a set of strains that can be utilized to validate the effectiveness of mycoplasma clearance obtained by inactivation and viral purification processes used for the manufacture of an inactivated egg-based vaccine.

Mycoplasma hominis-associated parapharyngeal abscess following acute Epstein-Barr virus infection in a previously immunocompetent adult

Mycoplasma hominis most frequently causes diseases of the genitourinary tract. Extragenital infections are uncommon, with almost all occurring in immunosuppressed persons or those predisposed due to trauma or surgery. We present the case of a previously well man who developed an M. hominis-associated parapharyngeal abscess following acute Epstein-Barr virus infection.

Spontaneous bacterial pericarditis with tamponade due to Ureaplasma spp

Infectious pericardial effusion with tamponade is an uncommon but life-threatening disease. We report an unusual case of spontaneous Ureaplasma pericardial effusion with tamponade associated with pneumonia, pleural effusion, and urinary tract infection. All published cases of clinically invasive Ureaplasma infections in the adult population are also reviewed.

Ureaplasma parvum as a cause of sternal wound infection

Few reports in the literature have documented the isolation of Ureaplasma species from sternal wounds. A case of sternal wound infection likely due to Ureaplasma parvum is described. When routine bacterial cultures from a sternal wound infection fail to yield a pathogen, diagnostic testing for mycoplasmas and ureaplasmas should be considered.