Actinomyces meyeri, a Common Agent of Actinomycosis

Mediastinal Mass, Cancer, or Infection, Atypical Paraesophageal Actinomycosis Infection, Clinical and Surgical Approach

Actinomyces israelii (AI) is a Gram-positive, rod-shaped bacterium that lives commensally on and within humans as a typical colonizer within the gastrointestinal tract, including the mouth. As an opportunistic pathogen, infection often results from tissue injury or breach of the mucosal barrier (ie, during various dental or GI procedures, aspiration, or specific pathologies such as diverticulitis). Symptoms generally present slowly as a non-tender, indurated mass that evolves into multiple abscesses, fistulae, or draining sinus tracts without regard for anatomical barriers, including fascial planes or lymphatic drainage. However, it may also present as an acute suppurative infection with pain and rapid progression to abscess formation.

Actinomyces meyeri-induced brain abscess in pregnancy: a case report

BACKGROUND

Brain abscesses can occur when suppurative, bacterial or protozoan infections spread to the brain. Here, we report a rare case of Actinomyces meyeri-induced brain abscess in a pregnant woman.

CASE PRESENTATION

We present the case of a 38-years-old primipara admitted to the emergency department at our hospital with a 4-day history of fever and vomiting. The symptoms worsened rapidly during the 8 h prior to admission, and the patient experienced a sudden loss of consciousness 4 h before arrival to the unit. Brain magnetic resonance imaging revealed abnormal signals in the right parietal-temporal lobe, suggesting the possibility of abscess rupture into the ventricle and sulcus. Right lateral ventricle compression and midline structure deviation to the left were noted. A right temporal-occipital mass with midline shift was detected. Emergency procedures were promptly performed, including craniotomy, removal of the right temporal-occipital mass, decompressive craniectomy, implantation of an intracranial pressure monitoring device, and external ventricular drainage. Cerebrospinal fluid culture indicated infection with Actinomyces meyeri. After administration of antibiotics, including linezolid and meropenem injections, along with treatments to decrease intracranial pressure, the patient's vital signs stabilized. However, the patient developed hydrocephalus, requiring placement of a hydrocephalus shunt several months later. Throughout this period, the patient remained in a coma vigil state, and labor was induced for the fetus.

CONCLUSIONS

Although the patient did not present with any apparent predisposing causes for brain abscess, a scout view of CT revealed dental caries. In addition, the occurrence of the brain abscess may have been influenced by the hormonal changes during pregnancy, including increased secretion of estrogen and progesterone, as well as decreased immune function. Early diagnosis and intervention are crucial in such cases. Therefore, it is recommended to seek early medical attention if symptoms such as fever, vomiting, and changes in mental state occur during pregnancy, as the prognosis for both the mother and infant is poor once the abscess ruptures.

Actinomyces meyeri Causing Cerebral Abscess in a Patient on Methotrexate: A Rare Case Report and Systematic Review of the Literature

Central nervous system (CNS) actinomycosis is a rare, serious, life-threatening, suppurative infection caused by Actinomyces species. Actinomyces are anaerobic Gram-positive bacteria, which can be normally isolated from the polymicrobial flora of the gastrointestinal- and genital tracts. They are considered very low virulent bacteria to humans. However, they can lead to several types of local or disseminated infections, if certain pathologic states or immunodeficiency occur. Intracranial abscesses caused by Actinomyces meyeri are rarely reported in adults. In this case report, we describe a 66-year-old woman who presented to the emergency department due to progressive complaints of altered sensorium and low-grade fever, due to an A. meyeri-related brain abscess. The only risk factor was represented by immunodeficiency due to the therapy with Methotrexate and steroids.

Brain Abscess: A Rare Clinical Case with Oral Etiology

Brain abscess is a very rare condition but has a significant mortality rate. The three main routes of inoculation are trauma, contiguous focus, and the hematogenous route. The odontogenic focus is infrequent and is usually a diagnosis of exclusion. This paper presents a brain abscess case proven to be of dental origin, caused by Actinomyces meyeri and Fusobacterium nucleatum. This case highlights the risk underlying untreated dental disease and why oral infectious foci removal and good oral health are essential in primary care.

Abdominal actinomycosis after reparative surgery for cholecystogastric fistula in an immunosuppressed patient

A male patient, aged over 75 years, was referred to the emergency room for pain in his right hypochondrium. This pain, which persisted for approximately 3 days, radiated to his right flank and right iliac quadrant and worsened after meals. The patient reported no nausea, vomiting, diarrhoea, fever or recent traumatic events. Blood laboratory tests, ultrasonography, an MRI and a CT scan were performed, leading to the diagnosis of a mass in the Morrison's pouch with ultrasound features of adipose tissue compatible with a liposarcoma, infiltrating the liver and the right kidney. Subsequent CT-guided needle aspiration and a histological examination led to the diagnosis of actinomycosis. The patient was initially treated with a daily dose of 18 million IU of benzylpenicillin for 4 weeks and subsequently prescribed the oral administration of 3 g/day of amoxicillin for 11 months. A monitoring CT scan was performed after 1, 5, 8 and 12 months, and a CT scan re-evaluation confirmed that the mass had completely healed.

Sepsis due to Actinomyces odontolyticus as a Rare Complication of Neobladder

Sepsis due to Actinomyces odontolyticus (A. odontolyticus) is an extremely rare condition that has been reported only a handful of times. In this report, we showcase an 83-year-old male who had a complication of neobladder procedure and developed sepsis due to A. odontolyticus that was successfully treated with a prolonged course of doxycycline.

A rare case of voluminous brain abscess due to Actinomyces meyeri and Aggregatibacter aphrophilus: is there any evidence for a prolonged antibiotic oral relay?

We present the case of a patient with a voluminous cerebral abscess caused by Aggregatibacter aphrophilus and Actinomyces meyeri occurring a week post dental scaling. Both these bacteria are rarely involved in brain abscesses, and so far, cases of cerebral actinomyces have mostly been treated surgically and with intravenous (IV) antibiotics for 3-4 months, then put on oral antibiotic therapy with penicillin or amoxicillin for a further 3-12 months. Our patient underwent drainage through craniotomy and was subsequently put on intravenous ceftriaxone for 3 months accompanied by brain imaging control at the end of this period which showed complete regression of the abscess. Following parenteral treatment, no oral antibiotics were given since pharmacokinetic properties do not allow to attain high tissue concentration in the brain. This treatment gave excellent results.

Species diversity and molecular analysis of opportunistic Mycobacterium, Nocardia and Rhodococcus isolated from the hospital environment in a developing country, a potential resources for nosocomial infection

Background

Hospital environmental resources have a significant role in cross-transmission of opportunistic pathogens such as actinomycetes species to the patients. Actinomycetes have a remarkable capability to survive in adverse and harsh conditions of hospital environments; therefore, they are a threat to the health of patients. Due to this issue, we aimed to determine the frequency and diversity of actinomycetes species in hospital soil, water and dust by using a combination of conventional and molecular methods including the phenotypic and biochemical tests for preliminary identification and the PCR amplification of the specific region of the 16S rRNA, hsp65 gene and sequence analyses of 16S rRNA for the genus and species identification.

Results

A total of 50 (35.2%) actinomycetes isolates from 7 genera were isolated from 142 hospital environmental samples. The three most prevalent species were M. setense 10%, R. erythropolis and M. fortuitum 8% followed by N.cyriacigeorgica and M. gordonae 6%, M. chelonae, M. abscessus, M. lentiflavum, M. mucogenicum, N. asteroides, N. farcinica, R. equi and L. shinushuensis 4% and the single isolates of M. conceptionense, M. septicum, N. rhamnosophilia, N. bravicatena, M. flavescens, M. arupense, M. doricum, M. frederiksbergense, S. heliomycini, S. albus, S. albogriseolus, R. facians, D. maris, G. terae and A. globiformis.

Conclusions

In conclusion we showed that the hospital environment is a potential reservoir for a broad range of actinomycetes species, due to the remarkable survival capability of these microorganisms in adverse hospital environment, carrying a threat to the health of patients.

Actinomyces meyeri: A Rare Cause of Postsurgical Pelvic Actinomycosis

Actinomyces meyeri bacterium resides on mucosal surfaces and is uncommonly pathogenic. When A. meyeri does cause infection, these infections are typically pulmonary in origin and have the capacity to disseminate throughout the body. A. meyeri is an uncommon cause of pelvic infection. We present a unique case of a posthysterectomy abscess caused by this particular bacterium.

"Pulmonary Actinomycosis attributable to Actinomyces meyeri presenting as cardiac tamponade: a case report"

BACKGROUND

Recently, it is reported that Actinomyces meyeri is the most common species causing actinomycosis. However, to our knowledge, there was no report about pulmonary actinomycosis attributable to A. meyeri presenting as cardiac tamponade.

CASE PRESENTATION

Hereby we describe a case of pulmonary actinomycosis attributable to A. meyeri presenting as cardiac tamponade. At first, the patient was diagnosed with bacterial pericarditis with lung abscess in the left lower lung lobe and underwent pericardial drainage. Three days after the removal of the drainage tube, atrial fibrillation followed by cardiac arrest with asystole occurred and immediate cardiopulmonary resuscitation restored his circulation. Thereafter, he underwent pneumocentesis of the lung abscess and the culture grew A. meyeri. He was successfully treated with penicillin G.

CONCLUSION

This is the first case of pulmonary actinomycosis attributable to A. meyeri presenting as cardiac tamponade. We believe that an increased awareness of the disease is necessary to expedite diagnosis therefore minimizing morbidity and mortality.

Emerging role of Actinomyces meyeri in brain abscesses: A case report and literature review

We describe a case of a 29-year-old man from Pakistan who presented with progressive neurologic symptoms over 1 week and was found to have a right parietal cerebral abscess. Neurosurgical drainage cultures showed growth of Actinomyces meyeri, Streptococcus intermedius, and Parvimonas micra. An abscessed molar was identified as the likely port of entry and was extracted. The patient was treated with metronidazole, vancomycin, and doxycycline because of prior anaphylaxis to penicillin. At 6-month follow-up, repeat magnetic resonance imaging showed no signs of residual abscess. Culture-independent identification techniques (e.g., ribosomal sequencing) increasingly identify Actinomyces meyeri as a causative agent and significant pathogen in spontaneous brain abscesses. As understanding about Actinomyces meyeri’s prevalence and pathogenesis improves, questions arise about optimal treatment strategy, which we discuss based on a literature review.