Is the Presence of Actinomyces spp. in Blood Culture Always Significant?

Understanding Actinomyces Odontolyticus: A Rare Culprit of Bacteremia

Actinomyces species are gram-positive filamentous non-acid fast anaerobic to microaerophilic bacteria that belong to human oral, gastrointestinal, and urogenital tract flora. Cervicofacial, abdominopelvic, and pulmonary infections are the most common presentations. Hematogenous spread is extremely rare and has been associated with Actinomyces meyeri, Actinomyces israelii, and Actinomyces odontolyticus. It affects individuals with poor oral hygiene, heavy alcohol intake, immunosuppressed, and underlying pulmonary diseases typically between the second and sixth decades of life with the peak incidence being between the fourth and fifth decades. We present a case of A. odontolyticus bacteremia in a patient with uncontrolled diabetes mellitus and chronic sinusitis.

Polymicrobial infections with specific Actinomyces and related organisms, using the current taxonomy

Actinomyces organisms reside on mucosal surfaces of the oropharynx and the genitourinary tract. Polymicrobial infections with Actinomyces organisms are increasingly being reported in the literature. Since these infections differ from classical actinomycosis, lacking of specific clinical and imaging findings, slow-growing Actinomyces organisms can be regarded as contaminants or insignificant findings. In addition, only limited knowledge is available about novel Actinomyces species and their clinical relevance. The recent reclassifications have resulted in the transfer of several Actinomyces species to novel genera Bowdeniella, Gleimia, Pauljensenia, Schaalia, or Winkia. The spectrum of diseases associated with specific members of Actinomyces and these related genera varies. In human infections, the most common species are Actinomyces israelii, Schaalia meyeri, and Schaalia odontolytica, which are typical inhabitants of the mouth, and Gleimia europaea, Schaalia turicensis, and Winkia neuii. In this narrative review, the purpose was to gather information on the emerging role of specific organisms within the Actinomyces and related genera in polymicrobial infections. These include Actinomyces graevenitzii in pulmonary infections, S. meyeri in brain abscesses and infections in the lower respiratory tract, S. turicensis in skin-related infections, G. europaea in necrotizing fasciitis and skin abscesses, and W. neuii in infected tissues around prostheses and devices. Increased understanding of the role of Actinomyces and related species in polymicrobial infections could provide improved outcomes for patient care. Key messages Due to the reclassification of the genus, many former Actinomyces species belong to novel genera Bowdeniella, Gleimia, Pauljensenia, Schaalia, or Winkia.Some of the species play emerging roles in specific infection types in humans.Increasing awareness of their clinical relevance as an established or a putative pathogen in polymicrobial infections brings about improved outcomes for patient care.

A 5-year retrospective study of Actinomyces odontolyticus bacteremia in the state of Qatar, case series

Introduction and importance

Manifestations of infection by A. odontolyticus include thoracic, abdominal, pelvic, and central nervous system disease. In the four decades following its isolation, more than 20 cases of invasive infections were reported in multiple geographic locations including the United States and Europe. As such, A. odontolyticus is an emerging bacterium and related research is encouraged for further characterization of its prevalence and clinical significance. Our case series represents the first case series about A. odontolyticus bacteremia in the state of Qatar.

Methods

We are reporting 15 cases with isolated A. odontolyticus positive blood cultures at Hamad Medical Corporation, State of Qatar from 1/Jan/2016 to 1/Nov/2020. Electronic health records (EHR) of patients who were identified to have positive blood cultures were accessed and the demographics and other clinically related data were collected and mentioned in this manuscript, after obtaining the appropriate approval from the Corporation Medical Research Council (MRC).

Outcomes

We are reporting 15 cases with isolated A. odontolyticus positive blood cultures at Hamad Medical Corporation, State of Qatar from 1/Jan/2016 to 1/Nov/2020.

Conclusion

12 of the 15 reported cases were considered significant and received a complete course of antimicrobial therapy. The patients presented with a wide variety of clinical pictures and were of variable age.

•

A. odontolyticus is an emerging bacterium with increasingly reported cases.

•

It is an anaerobic, filamentous gram-positive bacterium.

•

It is associated with cervical, thoracic, abdominal, and pelvic infections.

•

It can affect a wide spectrum of patient population.

Clinical Characteristics of Actinomyces viscosus Bacteremia

Background and Objectives: Actinomyces species are part of the normal flora of humans and rarely cause disease. It is an uncommon cause of disease in humans. The clinical features of actinomycosis have been described, and various anatomical sites (such as face, bones and joints, respiratory tract, genitourinary tract, digestive tract, central nervous system, skin, and soft tissue structures) can be affected. It is not easy to identify actinomycosis because it sometimes mimics cancer due to under-recognition. As new diagnostic methods have been applied, Actinomyces can now more easily be identified at the species level. Recent studies have also highlighted differences among Actinomyces species. We report a case of Actinomyces viscosus bacteremia with cutaneous actinomycosis. Materials and Methods: A 66 years old male developed fever for a day with progressive right lower-leg erythematous swelling. Blood culture isolates yielded Actinomyces species, which was identified as Actinomyces viscosus by sequencing of the 16S rRNA gene. In addition, we searched for the term Actinomyces or actinomycosis cross-referenced with bacteremia or "blood culture" or "blood stream" from January 2010 to July 2020. The infectious diseases caused by species of A. viscosus from January 1977 to July 2020 were also reviewed. Results: The patient recovered well after intravenous ampicillin treatment. Poor oral hygiene was confirmed by dental examination. There were no disease relapses during the following period. Most cases of actinomycosis can be treated with penicillin. However, clinical alertness, risk factor evaluation, and identification of Actinomyces species can prevent inappropriate antibiotic or intervention. We also compiled a total of 18 cases of Actinomyces bacteremia after conducting an online database search. Conclusions: In summary, we describe a case of fever and progressive cellulitis. Actinomyces species was isolated from blood culture, which was further identified as Actinomyces viscosus by 16S rRNA sequencing. The cellulitis improved after pathogen-directed antibiotics. Evaluation of risk factors in patients with Actinomyces bacteremia and further identification of the Actinomyces species are recommended for successful treatment.

Atypical Burkholderia Cepacia Resistance to Ceftazidime/Avibactam and Co-trimoxazole: A Case of Open Wound Contamination and Persistent Bacteremia

Wound contamination and subsequent colonization by microbes can significantly impair tissue repair and lead to the development of chronic non-healing ulcers. Atypical Burkholderia and Actinomycetes bacterial species are common in cases of soil contamination of open wounds leading to a complex infection that is both difficult to diagnose and treat. Despite much research on the involvement of atypical organisms, including Burkholderia and Actinomycetes, in antibiotic resistance, there is no consensus on the timeline from contamination to infection and on an algorithm for early diagnosis and management. Thus, the ways in which these organisms interact in settings of co-infection and contribute to cross-resistance remains unclear. The generally low index of clinical suspicion for atypical microbial infections and the absence of clear diagnostic protocols have multiple consequences, ranging from excessive reliance on pathology, delayed treatment, expensive and ineffective investigations and treatment, and progressive wound sepsis and morbidity. We are reporting a case of Burkholderia cepacia infection, co-infection with Actinomyces spp., and resistance to ceftazidime/avibactam and co-trimoxazole in a 28-year-old previously healthy farmer following soil contamination of an open wound. This is one of only a few reported cases of Burkholderia resistance to ceftazidime/avibactam and the first reported case ofB. cepacia bacteremia due to peripheral contamination.

A case report of primary sternal osteomyelitis caused by polymicrobial bacteria, including Actinomyces israelii

•

Actinomyces species colonize the human oropharynx, gastrointestinal tract, and urogenital tract.

•

Primary sternal osteomyelitis is very rare, especially caused by Actinomyces israelii.

•

Actinomycosis requires long-term antibiotic treatment.

•

A. israelii should be included in the differential diagnosis as a causative pathogen of osteomyelitis.

We herein report a case of primary sternal osteomyelitis caused by polymicrobial bacteria, including Actinomyces israelii. A 72-year-old man presented with a fever and precordial pain. Chest computed tomography (CT) revealed peristernal fluid associated with an osteolytic lesion and a peripheral nodule in the right upper lobe. We suspected sternal osteomyelitis, and an incision and drainage were performed. Culture of the drainage fluid and bone tissue yielded A. israelii, Fusobacterium necrophorum, and Streptococcus constellatus. Treatment with benzylpenicillin potassium (PCG) was administered. A subsequent chest CT scan showed that the peripheral nodule decreased in size after antimicrobial therapy. We therefore presumed the peripheral nodule as septic pulmonary embolism(SPE). Antimicrobial agents were administered for a total of 6 months. To our knowledge, this is the first case report of primary sternal osteomyelitis associated with presumed SPE caused by polymicrobial bacteria, including A. israelii. It is important to identify the causative pathogen in osteomyelitis, which requires long-term antibiotic treatment.

Preterm Labor Caused by Hemolysis, Elevated Liver Enzymes, Low Platelet Count (HELLP) Syndrome and Postpartum Infection Complicated with Actinomyces Species: A Case Report

Patient: Female, newborn

Final Diagnosis: Actinomyces infection

Symptoms: Premature labor

Medication: —

Clinical Procedure: —

Specialty: Infectious Disease