Salvage heart transplantation for Mycoplasma hominis prosthetic valve endocarditis: A case report and review of the literature

Deciphering the genetic basis of resistome and virulome diversity among multidrug-resistant Mycoplasma hominis

Mycoplasma hominis, a commensal bacterium that commonly inhabits the genital tract, leading to infections in both the genitourinary and extragenital regions. However, the antimicrobial resistance and pathogenic mechanisms of M. hominis isolated from extra-urogenital cystic abscess is largely unknown. This study reports the genomic epidemiological characteristics of a M. hominis isolate recovered from a pelvic abscess sample in China. Genomic DNA was extracted and sequenced using Illumina HiSeq X Ten platform. De novo assembly was performed and in silico analysis was accomplished by multiple bioinformatics tools. For phylogenomic analysis, publicly available M. hominis genomes were retrieved from NCBI GenBank database. Whole genome sequencing data showed that the genome size of M. hominis MH4246 was calculated as 679,746 bp, with 558 protein-coding sequences and a G + C content of 26.9%. M. hominis MH4246 is resistant to fluoroquinolones and macrolides, harboring mutations in the quinolone resistance-determining regions (QRDRs) (GyrA S153L, ParC S91I and ParE V417I) and 23S rRNA gene (G280A, C1500T, T1548C and T2218C). Multiple virulence determinants, such as tuf, hlyA, vaa, oppA, MHO_0730 and alr genes, were identified. Phylogenetic analysis showed that the closest relative of M. hominis MH4246 was the strain MH-1 recovered from China, which differed by 3490 SNPs. Overall, this study contributes to the comprehension of genomic characteristics, antimicrobial resistance patterns, and the mechanisms underlying the pathogenicity of this pathogen.

Extra-urogenital infection by Mycoplasma hominis in transplant patients: two case reports and literature review

BACKGROUND

Mycoplasma hominis is a facultative anaerobic bacterium commonly present in the urogenital tract. In recent years, M. hominis has increasingly been associated with extra-urogenital tract infections, particularly in immunosuppressed patients. Detecting M. hominis in a diagnostic laboratory can be challenging due to its slow growth rate, absence of a cell wall, and the requirements of specialized media and conditions for optimal growth. Consequently, it is necessary to establish guidelines for the detection of this microorganism and to request the appropriate microbiological work-up of immunosuppressed patients.

CASE PRESENTATION

We hereby present two cases of solid organ transplant patients who developed M. hominis infection. Microscopic examination of the bronchial lavage and pleural fluid showed no microorganisms. However, upon inoculating the specimens onto routine microbiology media, the organism was successfully identified and confirmation was performed using 16S rDNA sequencing. Both patients received appropriate treatment resulting in the resolution of M. hominis infection.

CONCLUSIONS

The prompt detection of M. hominis in a clinical specimen can have a significant impact on patient care by allowing for early intervention and ultimately resulting in more favorable clinical outcomes, especially in transplant patients.

Heart transplantation as salvage treatment of intractable infective endocarditis

BACKGROUND

For infective endocarditis (IE) with extensive perivalvular lesions or end-stage cardiac failure, heart transplantation (HT) may be the last resort.

METHODS

We retrospectively collected all cases of HT for IE within the International Collaboration on Endocarditis (ICE) network.

RESULTS

Between 1991 and 2021, 20 patients (5 women, 15 men), median age 50 years [interquartile range, 29-61], underwent HT for IE in Spain (n = 9), France (n = 6), Switzerland (n = 2), Colombia, Croatia, and USA (n = 1). IE affected prosthetic (n = 10), and native valves (n = 10), primarily aortic (n = 11) and mitral (n = 6). The main pathogens were oral streptococci (n = 8), Staphylococcus aureus (n = 5), and Enterococcus faecalis (n = 2). The major complications included heart failure (n = 18), peri-annular abscess (n = 10), and prosthetic valve dehiscence (n = 4). Eighteen patients had previous cardiac surgery for this episode of IE, and four were on circulatory support before HT (left ventricular assist-device and extra-corporeal membrane oxygenation, 2 patients each). The median time interval between first symptoms of IE and HT was 44.5 days [22-91.5]. The main post-HT complication was acute rejection (n = 6). Seven patients died (35%), four during the first month post-HT. Thirteen (81%) of the 16 patients discharged from the hospital survived with a median follow-up of 35.5 months [4-96.5] after HT, and no relapse of IE.

CONCLUSIONS

IE is not an absolute contraindication for HT: Our case series and the literature review support that HT may be considered as a salvage treatment in highly-selected patients with intractable IE.

A subacute presentation of Mycoplasma hominis prosthetic valve endocarditis

Mycoplasma hominis is a rare but important cause of prosthetic valve endocarditis. It is usually associated with acute progression of symptoms and can be difficult to diagnose as it does not grow in standard culture media. We report a case of an immunocompetent man in his 70s who presented with 14-month subacute decline with shortness of breath and evidence of a splenic infarct. Following a redo aortic valve replacement and diagnosis of M. hominis through 16S ribosomal ribonucleic acid PCR, he improved clinically with oral doxycycline therapy. He remained well at follow-up 2 years post-cessation of antibiotics. We present a literature review highlighting the role of PCR testing in the microbiological identification of M. hominis.

Diagnosis of Mycoplasma hominis Meningitis with Metagenomic Next-Generation Sequencing: A Case Report

Background

Mycoplasma hominis meningitis is a rare postoperative complication of neurosurgery. Accurate and early diagnosis of M. hominis remains challenging because of the limitations of traditional detection methods. Metagenomic next-generation sequencing (mNGS) is an advanced technique with high sensitivity and specificity for identifying infectious pathogens; however, its application in diagnosing M. hominis meningitis has not been widely studied.

Case Presentation

We report the case of a 61-year-old man who presented with fever and headache after neurosurgical treatment for a cerebral hemorrhage. Empiric antibiotic therapy was ineffective. Traditional culture of pathogens and serological testing yielded negative results, but M. hominis was detected in the cerebrospinal fluid by mNGS. After further verification by polymerase chain reaction (PCR), the patient's clinical treatment was adjusted accordingly. With targeted antibiotic intervention, the patient's symptoms were effectively alleviated, and clinical indicators returned to normal levels. Furthermore, the abundance of M. hominis decreased significantly compared to the initial mNGS reading after targeted treatment, indicating that the infection caused by M. hominis was effectively controlled.

Conclusion

Using mNGS, we found that M. hominis may be a candidate causative agent of meningitis. The technique also has the advantage of timeliness and accuracy that traditional cultures cannot achieve. A combination of mNGS with PCR is recommended to identify pathogens in the early stages of infectious diseases to administer targeted clinical medication.

Blood Culture-Negative Infective Endocarditis by Mycoplasma hominis: Case Report and Literature Review

Mycoplasma hominis is a habitual colonizing microorganism of the lower genital tract but can exceptionally be the causal agent of blood culture-negative infective endocarditis (IE). Only 11 cases of this entity have been published to date. The study objectives were to describe the first case diagnosed in our center of IE by M. hominis on pacemaker lead and to carry out a narrative review. Among published cases of IE by this microorganism, 72.7% were male, with a mean age of 45 years and a history of valve surgery; the diagnosis was by culture (54.5%) or molecular technique (45.5%), and the prognosis was favorable in 72.7% of cases. The most frequently prescribed antibiotics were doxycycline, quinolones, and clindamycin.

Mycoplasma hominis: An under recognized pathogen

Mycoplasma hominis, a commensal of the genital tract, is a potential underestimated pathogen causing both genitourinary and extragenital infections including neonatal infections. Septic arthritis, prosthetic joint infection, central nervous system (CNS) infections, infective endocarditis and abscess formation are common extragenital infections associated mainly with immunocompromised patients. Mycoplasma hominis lipoproteins play an important role in pathogenicity and directly interact with the host immune system. Polymerase chain reaction (PCR) is the mainstay of diagnosis. Increasing resistance to tetracyclines and quinolones which are used for treatment, is a matter of global concern. We reviewed PubMed literature and Google search engine on the recent developments of association of Mycoplasma hominis with various diseases, pathogenesis, diagnosis and treatment.