Mycoplasma hominis bloodstream infection and persistent pneumonia in a neurosurgery patient: a case report.

BACKGROUND: Mycoplasma hominis is typically associated with a urogenital tract infection, while its association with bacteremia and pneumonia is rare and therefore easily overlooked. Here we report a M. hominis bloodstream infection and pneumonia in a surgical patient. CASE PRESENTATION: A 56-year-old male with symptoms of pneumonia underwent microsurgery and decompressive craniectomy after a left basal ganglia hemorrhage. The patient recovered well from surgery, but pulmonary symptoms progressively worsened, with antimicrobial therapies seemingly ineffective. Culturing of bilateral blood samples resulted in pin-point-sized colonies on blood agar plates, which were subsequently identified as M. hominis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Furthermore, sequencing of bronchoalveolar lavage samples also identified M. hominis as the main pathogen responsible for the pulmonary symptoms. The M. hominis strain was ciprofloxacin resistant, but susceptible to doxycycline and moxifloxacin. Doxycycline and moxifloxacin were subsequently used in a successful combination therapy that finally alleviated the patient's fever and resulted in absorption of pleural effusion. At 1-month follow-up, following complaints of dysuria, a prostate abscess containing M. hominis was detected as the likely primary source of infection. The abscess was successfully drained and treated with doxycycline. CONCLUSIONS: Mycoplasma hominis should be considered as a source of bloodstream infections and pneumonia, particularly when the response to standard antimicrobial therapy is limited. In this case, effective antimicrobial therapy was only commenced after identification of M. hominis and antimicrobial susceptibility testing.

The Impact of Selected Bacterial Sexually Transmitted Diseases on Pregnancy and Female Fertility.

Sexually transmitted infections (STIs) caused by Neisseria gonorrhoeae, Chlamydia trachomatis and Mycoplasma genitalium are a common cause of pelvic inflammatory disease (PID) which can lead to tubal factor infertility (TFI). TFI is one of the most common causes of infertility, accounting for 30% of female fertility problems. STIs can also have an impact on pregnancy, leading to adverse pregnancy outcomes. Escalating antibiotic resistance in Neisseria gonorrhoeae and Mycoplasma genitalium represents a significant problem and can be therapeutically challenging. We present a comprehensive review of the current treatment options, as well as the molecular approach to this subject. We have given special attention to molecular epidemiology, molecular diagnostics, current and new treatments, and drug resistance.

Cross-sectional study of urethral exposures at last sexual episode associated with non-gonococcal urethritis among STD clinic patients.

OBJECTIVE: Although Chlamydia trachomatis (CT) and Mycoplasma genitalium (MG) are major causes of non-gonococcal urethritis (NGU), up to 50% of cases are of unknown aetiology. We sought to identify urethral exposures at last sexual episode associated with NGU and non-CT/non-MG NGU to identify anatomical sites from which aetiologically relevant micro-organisms may be acquired. METHODS: We enrolled STD clinic patients with and without NGU assigned male sex at birth and age ≥16 into a cross-sectional study. NGU was urethral symptoms or visible discharge plus ≥5 polymorphonuclear leucocytes without Neisseria gonorrhoeae. Urine was tested for CT and MG (Aptima). We used logistic regression to estimate the association between urethral exposures at last sex and NGU separately among cisgender men and transgender women who have sex with men (MSM/TGWSM) and cisgender men who have sex with women (MSW). RESULTS: Between 8 August 2014 and 1 November 2017, we enrolled 432 patients, including 183 MSM/TGWSM (118 NGU+, 65 NGU-) and 249 MSW (126 NGU+, 123 NGU-). The mean age was 34; 59% were white. CT and MG were detected in 72 (30%) and 49 (20%) NGU+ participants, respectively. Compared with MSM/TGWSM reporting only non-urethral exposures at last sex, those reporting insertive anal intercourse (IAI) only (adjusted OR (AOR)=4.46, 95% CI 1.09 to 18.19) and IAI with insertive oral sex (IOS) (AOR=7.88, 95% CI 2.67 to 23.26) had higher odds of NGU. MSM/TGWSM reporting IOS only had no significant increased odds (AOR=1.67, 95% CI 0.58 to 4.85). Compared with MSW whose only urethral exposure at last sex was vaginal sex (VS), MSW reporting IOS and VS had similar odds of NGU (OR=0.84, 95% CI 0.50 to 1.41). The results were similar for non-CT/non-MG NGU. CONCLUSIONS: Among MSM/TGWSM, IAI may lead to transmission of yet-unidentified rectal micro-organisms that cause non-CT/non-MG NGU, in addition to transmission of known pathogens. Sites of urethral exposure appear less important for understanding NGU risk among MSW due to minimal variation in behaviour.

Infection due to Mycoplasma hominis after left hip replacement: case report and literature review.

BACKGROUND: Hip replacement is generally conducted in those with prolonged arthritis pain or hip fractures, and postoperative infection is a serious complication. Mycoplasma hominis, belonging to mycoplasma species, exists mainly in the genitourinary tract. M. hominis infection after total hip replacement was rarely documented in literature. CASE PRESENTATION: A 59-year-old male was febrile after left total hip replacement. Empiric therapy with cefepime for suspected infection was ineffective. Specimens at the infection site were collected for culture, and pinpoint colonies grew after incubation at 35 °C for 48 h on blood agar plate. They grew to approximately 0.5 mm colonies in diameter after 7-day incubation, and were identified as M. hominis. Sequentially, combination therapy with clindamycin hydrochloride and moxifloxacin was initiated, and the patient defervesced within 3 days and was discharged home. CONCLUSIONS: The study highlighted the potential pathogenicity of M. hominis in postoperative infection. The possibility of this microorganism involvement should be valued if the patients who experienced the hip or joint replacement had inexplicable fever.

Donor-Derived Mycoplasma hominis and an Apparent Cluster of M. hominis Cases in Solid Organ Transplant Recipients.

BACKGROUND: Invasive and disseminated Mycoplasma hominis infections are well recognized but uncommon complications in solid organ transplant recipients. In a single center, a cluster of M. hominis infections were identified in lung transplant recipients from the same thoracic intensive care unit (ICU). We sought to determine the source(s) of these infections. METHODS: Medical records of the donor and infected transplant recipients were reviewed for clinical characteristics. Clinical specimens underwent routine processing with subculture on Mycoplasma-specific Hayflick agar. Mycoplasma hominis identification was confirmed using sequencing of the 16S ribosomal RNA gene. Mycoplasma hominis isolates were subjected to whole-genome sequencing on the Illumina NextSeq platform. RESULTS: Three lung transplant recipients presented with invasive M. hominis infections at multiple sites characterized by purulent infections without organisms detected by Gram staining. Each patient had a separate donor; however, pretransplant bronchoalveolar lavage fluid was only available from the donor for patient 1, which subsequently grew M. hominis. Phylo- and pangenomic analyses indicated that the isolates from the donor and the corresponding recipient (patient 1) were closely related and formed a distinct single clade. In contrast, isolates from patients 2 and 3 were unrelated and divergent from one another. CONCLUSIONS: Mycoplasma hominis should be considered a cause of donor-derived infection. Genomic data suggest donor-to-recipient transmission of M. hominis. Additional patients co-located in the ICU were found to have genetically unrelated M. hominis isolates, excluding patient-to-patient transmission.

The infection of Mycoplasma hominis after total knee replacement: Case report and literature review.

The Mycoplasma hominis infection is a rare postoperative complication after joint replacement. Based on our knowledge, there were only two cases reported by Korea all over the world currently. A case of postoperative Mycoplasma hominis infection after total knee replacement in our hospital was reported in this article. It was confirmed through mass spectrometer and Mycoplasma cultivation and treated by the first stage debridement, polyethylene insert replacement, and then drainage and irrigation combined with sensitive antibiotics after the operation. We observed that the C reactive protein (CRP) level correlates with the development of disease, while the erythrocyte sedimentation rate (ESR) remains at a high level, indicating the relevance between the Mycoplasma hominis infection caused by knee joint replacement and CRP. This study aims to report the case and review relevant literature.

Changes in corticosterone concentrations and behavior during Mycoplasma gallisepticum infection in house finches (Haemorhous mexicanus).

Glucocorticoid stress hormones are important for energy mobilization as well as regulation of the immune system, and thus these hormones are particularly likely to both influence and respond to pathogen infection in vertebrates. In this study, we examined how the glucocorticoid stress response in house finches (Haemorhous mexicanus) interacts with experimental infection of the naturally-occurring bacterial pathogen, Mycoplasma gallisepticum (MG). We also investigated whether infection-induced concentrations of corticosterone (CORT), the primary glucocorticoid in birds, were associated with the expression of sickness behavior, the lethargy typically observed in vertebrates early in infection. We found that experimental infection with MG resulted in significantly higher CORT levels on day 5 post-infection, but this effect appeared to be limited to female house finches only. Regardless of sex, infected individuals with greater disease severity had the highest CORT concentrations on day 5 post-infection. House finches exposed to MG exhibited behavioral changes, with infected birds having significantly lower activity levels than sham-inoculated individuals. However, CORT concentrations and the extent of sickness behaviors exhibited among infected birds were not associated. Finally, pre-infection CORT concentrations were associated with reduced inflammation and pathogen load in inoculated males, but not females. Our results suggest that the house finch glucocorticoid stress response may both influence and respond to MG infection in sex-specific ways, but because we had a relatively low sample size of males, future work should confirm these patterns. Finally, manipulative experiments should be performed to test whether the glucocorticoid stress response acts as a brake on the inflammatory response associated with MG infection in house finches.

Genomic Investigations unmask Mycoplasma amphoriforme, a new respiratory pathogen.

BACKGROUND: Mycoplasma amphoriforme has been associated with infection in patients with primary antibody deficiency (PAD). Little is known about the natural history of infection with this organism and its ability to be transmitted in the community. METHODS: The bacterial load was estimated in sequential sputum samples from 9 patients by quantitative polymerase chain reaction. The genomes of all available isolates, originating from patients in the United Kingdom, France, and Tunisia, were sequenced along with the type strain. Genomic data were assembled and annotated, and a high-resolution phylogenetic tree was constructed. RESULTS: By using high-resolution whole-genome sequencing (WGS) data, we show that patients can be chronically infected with M. amphoriforme manifesting as a relapsing-remitting bacterial load, interspersed by periods when the organism is undetectable. Importantly, we demonstrate transmission of strains within a clinical environment. Antibiotic resistance mutations accumulate in isolates taken from patients who received multiple courses of antibiotics. CONCLUSIONS: Mycoplasma amphoriforme isolates form a closely related species responsible for a chronic relapsing and remitting infection in PAD patients in the United Kingdom and from immunocompetent patients in other countries. We provide strong evidence of transmission between patients attending the same clinic, suggesting that screening and isolation may be necessary for susceptible patients. This work demonstrates the critical role that WGS can play in rapidly unraveling the biology of a novel pathogen.

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.

The impact of copper-containing and levonorgestrel-releasing intrauterine contraceptives on cervicovaginal cytology and microbiological flora: a prospective study.

OBJECTIVE: To compare vaginal microflora and cervical cytology before and after insertion of a copper-containing intrauterine device (Cu-IUD) or a levonorgestrel releasing-intrauterine system (LNG-IUS). METHODS: Between April 2009 and February 2011, all women requesting insertion of an intrauterine contraceptive for family planning or noncontraceptive indications were enrolled. One hundred and eight Cu-IUDs and 42 LNG-IUSs were placed. Cervical cytological and vaginal microbiological findings before insertion and after 12 months were recorded. RESULTS: With regard to cervical cytology, nonspecific inflammatory changes became more frequent (but not significantly so; p = 0.062) after one year of use of a Cu-IUD, whereas their prevalence remained unchanged among women fitted with a LNG-IUS. Colonisation by Candida spp. and mycoplasma infections were diagnosed significantly more often after one year of use of the Cu-IUD than at baseline. During the study period, women wearing a Cu-IUD complained significantly more frequently of vaginal discharge, pelvic pain, and increased menstrual flow. CONCLUSION: Use of a Cu-IUD - but not that of a LNG-IUS - was associated with an alteration of the vaginal flora and showed a trend towards a higher frequency of nonspecific inflammatory changes affecting cervical cytology.

An uncommon case of Mycoplasma hominis infection after total disc replacement.

PURPOSE: Beside mechanical complications, the majority of adverse events after total disc arthroplasty (TDA) are related to the surgical approach. Septic complications are very uncommon and only one previous case has been published. The objective of this article is to describe the clinical circumstances, treatment, and outcomes of septic complication after TDA at L4-L5, involving an uncommon pathogen (Mycoplasma hominis). METHODS: A 38-year-old woman underwent a MobiDisc(®) TDA at L4-L5 level for discogenic pain. One month postoperatively, she complained of acute low back and abdominal pain associated with fever (39 °C). C-reactive protein level was elevated (197 mg/L; normal <5 mg/L) and the white blood cell count was normal (7 × 10(9)/L; normal 4-10 × 10(9)/L). A computerized tomography (CT) showed a left psoas-based retroperitoneal abscess. Treatment consisted of open debridement, drainage and empirical antibiotic therapy. Intraoperative cultures yielded M. hominis after 7 days incubation. Antibiotic therapy was adapted and discontinued after 2 months. The patient had failed to mention earlier that she had been suffering from abnormal vaginal discharge for some time and was using an intrauterine contraceptive device. RESULTS: At 1.5-year follow-up, review confirmed healing of the infection with biological normalization without residual collection, radiolucent lines or osteolysis around the prosthesis at radiographs, CT and MRI. CONCLUSIONS: Mycoplasma hominis can be involved as an extragenital pathogen in musculoskeletal infections. Because its culture and identification are difficult, special media and real-time PCR are required in case of postoperative deep wound infection after anterior lumbar spine surgery, especially in the case of previous genitourinary infections, to decrease the delay in diagnosis and treatment.

Effect of infection route and concurrent infectious bronchitis virus vaccination on Mycoplasma gallisepticum disease pathology in an experimental model.

The study of Mycoplasma gallisepticum (MG) infection is needed, not only to understand the disease process but also to understand the mechanisms by which MG vaccines protect the host. Many model systems have been used to study the MG disease process. This work compared two different routes of infection (intratracheal versus eye drop) in commercial pullets, looking for differences in the pathology (air sac and tracheal lesion scores, and tracheal mucosal thickness) and the humoral immune response (measured by serum plate agglutination) of the host. The impact of concurrent infectious bronchitis virus vaccination on disease outcomes was also determined. Results showed that the intratracheal route of MG infection caused increased air sac and tracheal lesion scores and tracheal mucosal thickness at one week post infection, whereas the eye drop route produced no noticeable pathology. However, tracheal mucosal thicknesses of intratracheally challenged pullets were not statistically different from those of the eye drop challenged or control pullets at two and three weeks post infection. Concurrent infectious bronchitis virus vaccination had a negligible outcome on disease pathology. Vaccination of specific-pathogen-free chickens with the F-strain MG vaccine completely protected them against the effects of MG intratracheal infectious challenge, as evidenced by a lack of significant difference in air sac and tracheal lesion scores and tracheal mucosal thickness with those of unchallenged media control chickens.

Pathophysiological and molecular considerations of viral and bacterial infections during maternal-fetal and -neonatal interactions of SARS-CoV-2, Zika, and Mycoplasma infectious diseases.

During pregnancy, a series of physiological changes are determined at the molecular, cellular and macroscopic level that make the mother and fetus more susceptible to certain viral and bacterial infections, especially the infections in this and the companion review. Particular situations increase susceptibility to infection in neonates. The enhanced susceptibility to certain infections increases the risk of developing particular diseases that can progress to become morbidly severe. For example, during the current pandemic caused by the SARS-CoV-2 virus, epidemiological studies have established that pregnant women with COVID-19 disease are more likely to be hospitalized. However, the risk for intensive care unit admission and mechanical ventilation is not increased compared with nonpregnant women. Although much remains unknown with this particular infection, the elevated risk of progression during pregnancy towards more severe manifestations of COVID-19 disease is not associated with an increased risk of death. In addition, the epidemiological data available in neonates suggest that their risk of acquiring COVID-19 is low compared with infants (<12 months of age). However, they might be at higher risk for progression to severe COVID-19 disease compared with older children. The data on clinical presentation and disease severity among neonates are limited and based on case reports and small case series. It is well documented the importance of the Zika virus infection as the main cause of several congenital anomalies and birth defects such as microcephaly, and also adverse pregnancy outcomes. Mycoplasma infections also increase adverse pregnancy outcomes. This review will focus on the molecular, pathophysiological and biophysical characteristics of the mother/placental-fetal/neonatal interactions and the possible mechanisms of these pathogens (SARS-CoV-2, ZIKV, and Mycoplasmas) for promoting disease at this level.

[Peritonitis due to post-myomectomy Mycoplasma hominis infection].

A 36-year-old woman undergoing a myomectomy developed postoperative surgical-saite peritonitis and hematoma. Eight days postoperatively, she developed a 38 degrees C-plus fever and accumulated ascites, with fever unchanged despite antimicrobial beta-lactams therapy. Following transvaginal ascitic drainage, her fever disappeared. Recurrent 38 degrees C fever and inflammation were cured by clindamycin of 1.2 g/day. M. hominis detected from ascites drainage was considered the primary causative organism. Nongenito-urinary M. hominis infection is often difficult to detect, as in our case. Gram staining, for example, is not useful in ascertaining small organisms such as Mycoplasma spp. having no cell walls to stain. M. hominis grows slowly, requiring over three days to form colonies on blood agar plates, requiring time to identify pathogens. We report case showing the importance of suspecting M. hominis of causing gynecological surgical-site infection. When common bacterial pathogen cultures remain negative and when empiric beta-lactam antibiotic treatment is ineffective, M. hominis should be suspected. In conclusion, M. hominis should be considered a causative following myomectomy resection.

[A case of Mycoplasma hominis infection after bladder injury during cesarean section].

A 21-year-old female patient underwent emergency cesarean section and a postoperative hematoma occurred at the site of the uterine incision. The patient underwent laparotomy for hemostasis. An 3 cm perforation at the posterior wall of the bladder was identified. The bladder was repaired in two layers with an absorbable suture. Three days later she developed a fever of over 38 degrees C. Despite therapy with several antimicrobial agents, her fever persisted and the wound was opened. Computed tomography scan revealed an abscess at the site where the hematoma had formed. We present a case of severe wound infection that was caused by Mycoplasma hominis infection after cesarean section. Bladder perforation associated with cesarean section is uncommon. Mycoplasma hominis should be considered as a causative organism if an antimicrobial resistant infection occurs at the surgical site after a cesarean section.

Mycoplasma hominis pericarditis in a lung transplant recipient: review of the literature about an uncommon but important cardiothoracic pathogen.

Purulent pericarditis due to Mycoplasma hominis is rare, and is usually associated with mediastinitis or pleuritis following cardiothoracic surgery. We report the first case to our knowledge of isolated purulent pericarditis caused by M. hominis in a lung transplant recipient and review previously reported cases of this disease.

The silent presence of Mycoplasma hominis in patients with prostate cancer.

BACKGROUND: Mycoplasma hominis, an opportunistic pathogen in human genitourinary tract, can cause chronic infection in the prostate. Intracellular survival of M. hominis leads to a prolonged presence in the host cells that can affect the cell's biological cycle. In the present study, we aimed to evaluate the frequency of M. hominis DNA in prostate tissue of Iranian patients with prostate cancer (PCa) in comparison to a control group with benign prostatic hyperplasia (BPH). METHODS: This research was a retrospective case-control study using 61 archived formalin-fixed paraffin-embedded (FFPE) blocks of prostate tissue from patients with PCa and 70 FFPE blocks of patients with BPH. Real-time PCR, targeting two different genes, 16S rRNA and yidC, in the M. hominis genome was performed for all specimens. RESULTS: Out of 61 blocks of prostate biopsy from patients with PCa, eight samples (13%) were positive for M. hominis, while the bacterium was not detected in any of the 70 blocks of patients with BPH (P value, 0.002). CONCLUSIONS: The high frequency of M. hominis in patients with PCa likely shows a hidden role of the organism in prostate cancer during its chronic, apparently silent and asymptomatic colonization in prostate.

Effect of a live Mycoplasma synoviae vaccine on the production of eggshell apex abnormalities induced by a M. synoviae infection preceded by an infection with infectious bronchitis virus D1466.

An experimental study was conducted to assess the effect of a live Mycoplasma synoviae vaccine (Vaxsafe MS; Bioproperties Pty Ltd, Ringwood, Victoria, Australia) on M. synoviae-induced eggshell apex abnormalities (EAA). Four experimental groups of specified-pathogen-free white laying hens were made. All groups were inoculated with infectious bronchitis virus D1466 at 18 weeks of age. One group did not receive further treatment (non-vaccinated non-challenged (NVNC)). Two groups were vaccinated at 14 weeks of age against M. synoviae, and one of these groups was also challenged with an EAA-inducing M. synoviae strain 5 days after infectious bronchitis virus challenge (vaccinated non-challenged (VNC) and vaccinated challenged group (VC), respectively). The fourth group was not vaccinated but was challenged with M. synoviae (non-vaccinated challenged (NVC)). Eggs with EAA eggs were produced only in the NVC and VC groups. However, the proportion of eggs with EAA and the mean daily production of eggs with EAA per chicken was significantly lower (P<0.05) in the VC group (88/741 (11.9%) and 0.09+/-0.01 eggs per hen) compared with the NVC group (148/646 (22.9%) and 0.14+/-0.01 eggs per hen). The mean daily egg production per chicken was significantly lower in the NVC group (0.48+/-0.03 eggs) compared with that of the NVNC group (0.60+/-0.03 eggs), but not significantly different from other groups. The eggshell strength of eggs with EAA (22.8 N) was significantly lower (P<0.05) than non-affected eggs from the other groups (33.7 to 39.5 N). Furthermore, the eggshell strength of non-affected eggs in the NVC group was significantly lower (P<0.05) compared with that of non-affected eggs from the flock of origin (33.7 versus 41.2 N), but not different from the other groups. It can be concluded from the present study that vaccination with a live M. synoviae vaccine reduces the occurrence of M. synoviae-induced EAA significantly.

Iatrogenic Ventriculitis Due to Mycoplasma Hominis: A Case Report and Review of the Literature.

BACKGROUND Mycoplasma hominis, which rarely causes infection after neurosurgical procedures, is a small free-living organism, belonging to the genus Mycoplasma. M. hominis lacks a rigid cell wall and cannot be clearly visualized by routine light microscopy. Thus, it is challenging to diagnose infections caused by this pathogen. Here, we report a case of Mycoplasma hominis causing iatrogenic ventriculitis secondary to extraventricular drain. CASE REPORT A 25-year-old man who was a victim of a road traffic accident developed M. hominis ventriculitis secondary to extraventricular drain. Despite a delay in the diagnosis due to the difficulty of identifying M. hominis, the patient was successfully treated with intravenous ciprofloxacin 400 mg for 14 days. CONCLUSIONS The findings of this case report, coupled with a thorough review of the literature, demonstrate the pathogenic potential of M. hominis. Particularly in developing countries, in which laboratories may have limited access to advanced technologies, such rare infectious diseases remain major diagnostic challenges.

Mycoplasma Ocular Infection in Subretinal Graft Transplantation of iPS Cells-Derived Retinal Pigment Epithelial Cells.

Purpose: To report occurrence of acute severe inflammation after surgical implantation of mycoplasma-infected induced pluripotent stem cell-derived RPE (iPS-RPE) cells into the eyes of healthy primates, and determine the immunopathological mechanisms of the inflammation. Methods: Ophthalmic allogeneic transplantation of iPS-RPE cells was performed in the subretina of major histocompatibility complex (MHC)-matched (two eyes) and MHC-mismatched (one eye) healthy cynomolgus monkeys. The clinical course after transplantation was observed using color fundus photography, fluorescence angiography, and optical coherence tomography. After the animals were killed at 1 month after surgery, eyeballs were removed and pathologically examined. Microorganisms were analyzed by PCR methods and BLAST analysis using preserved graft iPS-RPE cells and the recipients' vitreous humor. Mixed lymphocyte-RPE assay was performed on the mycoplasma-infected and noninfected iPS-RPE cells in vitro. Results: In tested eyes, abnormal findings were observed in the grafted retina 2 weeks after surgery. Here, we observed retinal vasculitis and hemorrhage, retinal detachment, and infiltration of inflammatory cells into the retina of the eyes. One month after surgery, animals were killed due to the severe immune responses observed. Using PCR methods, sequence analysis detected mycoplasma-DNA (Mycoplasma arginini species) in both the grafted RPE cells and the collected vitreous fluids of the monkeys. Mixed lymphocyte-RPE assay revealed that the infected iPS-RPE cells enhanced the proliferation of inflammatory cells in vitro. Conclusions: Transplantation of graft iPS-RPE cells contaminated with mycoplasma into the subretina caused severe ocular inflammation. Mycoplasma possesses the ability to cause immune responses in the host.