Microbiological and Clinical Aspects of Cervicofacial Actinomyces Infections: An Overview

Effects of glucose and lactate on Streptococcus mutans abundance in a novel multispecies oral biofilm model

The oral microbiome plays an important role in protecting oral health. Here, we established a controlled mixed-species in vitro biofilm model and used it to assess the impact of glucose and lactate on the ability of Streptococcus mutans, an acidogenic and aciduric species, to compete with commensal oral bacteria. A chemically defined medium was developed that supported the growth of S. mutans and four common early colonizers of dental plaque: Streptococcus gordonii, Actinomyces oris, Neisseria subflava, and Veillonella parvula. Biofilms containing the early colonizers were developed in a continuous flow bioreactor, exposed to S. mutans, and incubated for up to 7 days. The abundance of bacteria was estimated by quantitative polymerase chain reaction (qPCR). At high glucose and high lactate, the pH in bulk fluid rapidly decreased to approximately 5.2, and S. mutans outgrew other species in biofilms. In low glucose and high lactate, the pH remained above 5.5, and V. parvula was the most abundant species in biofilms. By contrast, in low glucose and low lactate, the pH remained above 6.0 throughout the experiment, and the microbial community in biofilms was relatively balanced. Fluorescence in situ hybridization confirmed that all species were present in the biofilm and the majority of cells were viable using live/dead staining. These data demonstrate that carbon source concentration is critical for microbial homeostasis in model oral biofilms. Furthermore, we established an experimental system that can support the development of computational models to predict transitions to microbial dysbiosis based on metabolic interactions.IMPORTANCEWe developed a controlled (by removing host factor) dynamic system metabolically representative of early colonization of Streptococcus mutans not measurable in vivo. Hypotheses on factors influencing S. mutans colonization, such as community composition and inoculation sequence and the effect of metabolite concentrations, can be tested and used to predict the effect of interventions such as dietary modifications or the use of toothpaste or mouthwash on S. mutans colonization. The defined in vitro model (species and medium) can be simulated in an in silico model to explore more of the parameter space.

Sigmoid colon pseudotumor of actinomycosis: a rare case

Actinomycosis is a chronic suppurative infection caused by gram-positive bacteria, Actinomyces, which commonly colonize the oral cavity, urogenital tract and gastrointestinal tract. It causes opportunistic infection where the mucosal barrier is compromised and is often misdiagnosed as malignancy. We report a case of a 58-year-old female with severe abdominal pain and a palpable tender mass in the left lower quadrant. Computed tomography scan with contrast showed thickening of the transverse, descending to sigmoid colon wall and intense contrast enhancement resembling colitis with mesenteritis. At laparotomy, we found an adherent mass involving sigmoid colon with adjacent small bowel and peritoneum. We decided to perform adhesiolysis and Hartmann procedure. The culture result was negative, whereas the biopsy of sigmoid colon revealed characteristic sulfur granules of actinomycosis colony. Intravenous antibiotic combination of ceftazidime and metronidazole was administered for 14 days followed by complete resolution of symptoms. Histopathological and bacteriological examinations are keys to diagnose actinomycosis. Patients require long-term antibiotic therapy, but surgery is often required because preoperative diagnosis is difficult.

Main novel aspects?

We presented the rare case of intra-abdominal actinomycosis in IndonesiaThe case was challenging to diagnose pre-operatively based on physical examination andExploratory laparotomy revealed pseudotumor mimicking advanced stage of colon neoplasm.

Role of Actinomyces spp. and related organisms in the development of medication-related osteonecrosis of the jaw (MRONJ): Clinical evidence based on a case series

Medication-related osteonecrosis of the jaw (MRONJ) is an increasingly common consequence of antiresorptive treatment, which often leads to the development of necrotic exposed bone surfaces with inflammatory processes affecting the jawbone. Although the development of MRONJ is often associated with the inflammatory response or infections caused by the colonizing members of the oral microbiota, the exact pathogenesis of MRONJ is still not fully understood. In the present paper, we aimed to provide additional, microbiological culture-supported evidence, supporting the "infection hypothesis" that Actinomyces spp. and related organisms may play an important pathogenic role in the development of MRONJ and the resulting bone necrosis. In our case series, all patients presented with similar underlying conditions and anamnestic data, and have received antiresorptive medications (bisphosphonates or a RANK ligand (RANKL) inhibitor) to prevent the occurrence or progression of bone metastases, secondary to prostate cancer. Nevertheless, a few years into antiresorptive drug therapy, varying stages of MRONJ was identified in the mentioned patients. In all three cases, quantitative microbiological culture of the necrotic bone samples yielded a complex microbiota, dominated by Actinomyces and Schaalia spp. with high colony counts. Additionally, our followed-up case series document the treatment of these patients with a combination of surgical intervention and long-term antibiotic therapy, where favourable clinical responses were seen is all cases. If the "infection hypothesis" is valid, it may have significant consequences in the preventative and therapeutic strategies associated with this disease.

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.

The role of Actinomyces spp. and related organisms in cervicofacial infections: Pathomechanism, diagnosis and therapeutic aspects

Members of the Actinomyces genus and Actinomyces-like organisms (ALOs; namely Actinotignum, Arcanobacterium, Schaalia and Varibaculum) are Gram-positive, non-spore-forming rods that are commensal members of the human oral cavity, gastrointestinal tract, female genital tract and skin microbiota. Cervicofacial actinomycosis or "lumpy jaw syndrome" - the chronic, suppurative granulomatous disease caused by Actinomyces spp. And ALOs - is characterized by an initially slow and unspecific disease-presentation, which often mimics other pathologies, followed by the formation of painful abscesses and severe tissue destruction. Actinomycosis has been described as a rare disease, however, reliable epidemiological data are lacking. In addition, there is increasing awareness regarding the role of Actinomyces spp. in the development of osteoradionecrosis and medication-related osteonecrosis of the jaw. The aim of this narrative review is to succinctly summarize the current advances regarding the microbiological, clinical, diagnostic and therapeutic aspects of cervicofacial actinomycosis, in addition to the roles of Actinomyces species and ALOs as members of the oral microbiota and in dental biofilm, in other dental infections (caries, root canal infection, periapical infection, periodontitis) and osteonecrosis of the jaw, in the context of recent taxonomic changes affecting the genus. Our paper aims to be a blueprint for dentists, other physicians, microbiologists and researchers regarding the multifaceted field of cervicofacial actinomycosis.

Detection and molecular characterization of Actinomyces denticolens causing lymph node abscessation in horses

Introduction

Abscessation of equine head lymph nodes can be caused by various bacteria, but Streptococcus equi subsp. equi is mainly involved. At our laboratory, samples of three unrelated horses with submandibular abscesses were found negative for S. equi, and further testing proved the presence of another genus. This raised the question for the exact identity of this pathogen and whether these isolates were epidemiologically related and it warranted further characterization with regards of virulence and resistance factors.

Methods

Culture followed by identification using MALDI-TOF MS, MIC testing and whole genome sequencing (WGS) was performed to characterize the bacteria.

Results

Bacterial culture and subsequent identification with MALDI-TOF MS resulted in the reliable identification of A. denticolens in two of the three cases. Final confirmation of A. denticolens for all three isolates was achieved by analysis of the WGS data, supported by multilocus sequence typing (MLST). The three isolates showed 95% nucleotide sequence identity. The number of single nucleotide polymorphisms (10,170 to 36,058) indicated that the isolates were not clonal, suggesting that these cases were epidemiologically unrelated. Only four known virulence related genes were detected. The absence of known antibiotic resistance genes was in line with the high susceptibility, as indicated by the susceptibility patterns obtained for two of the three isolates.

Conclusion

We conclude that A. denticolens should be included in the differential diagnosis of (submandibular) lymph node abscessation in horses, especially if strangles cannot be confirmed with laboratory diagnostics. Furthermore, we report the first draft genome of A. denticolens isolated from horses.

The epidemiology, clinical presentation and treatment outcomes in CNS actinomycosis: a systematic review of reported cases

BACKGROUND

CNS actinomycosis is a rare chronic suppurative infection with non-specific clinical features. Diagnosis is difficult due to its similarity to malignancy, nocardiosis and other granulomatous diseases. This systematic review aimed to evaluate the epidemiology, clinical characteristics, diagnostic modalities and treatment outcomes in CNS actinomycosis.

METHODS

The major electronic databases (PubMed, Google Scholar, and Scopus) were searched for the literature review by using distinct keywords: "CNS" or "intracranial" or "brain abscess" or "meningitis" OR "spinal" OR "epidural abscess" and "actinomycosis." All cases with CNS actinomycosis reported between January 1988 to March 2022 were included.

RESULTS

A total of 118 cases of CNS disease were included in the final analysis. The mean age of patients was 44 years, and a significant proportion was male (57%). Actinomycosis israelii was the most prevalent species (41.5%), followed by Actinomyces meyeri (22.6%). Disseminated disease was found in 19.5% of cases. Most commonly involved extra-CNS organs are lung (10.2%) and abdomen (5.1%). Brain abscess (55%) followed by leptomeningeal enhancement (22%) were the most common neuroimaging findings. Culture positivity was found in nearly half of the cases (53.4%). The overall case-fatality rate was 11%. Neurological sequelae were present in 22% of the patients. On multivariate analysis, patients who underwent surgery with antimicrobials had better survival (adjusted OR 0.14, 95% CI 0.04-0.28, p value 0.039) compared to those treated with antimicrobials alone.

CONCLUSION

CNS actinomycosis carries significant morbidity and mortality despite its indolent nature. Early aggressive surgery, along with prolonged antimicrobial treatment is vital to improve outcomes.

Paediatric pulmonary actinomycosis: A forgotten disease

Actinomycosis is a rare, indolent and invasive infection caused by Actinomyces species. Actinomycosis develops when there is disruption of the mucosal barrier, and invasion and systemic spread of the organism, which can lead to endogenous infection affecting numerous organs. It is known to spread in tissue through fascial planes and most often involves the cervicofacial (55%), abdominopelvic (20%) and thoracic (15%) soft tissue. Pulmonary actinomycosis is rare in patients under the age of five years, with the median reported age in the fifth decade. Clinical findings include chest wall mass (49%), cough (40%), pain (back, chest, shoulders) (36%), weight loss (19%), fever (19%), Draining sinuses (15%) and hemoptysis (9%). Chest x-ray findings in pulmonary actinomycosis are mostly nonspecific and can overlap with pulmonary tuberculosis, foreign body aspiration and malignancy. Endobronchial tissue aggregates may show sulphur granules, with yellow to white conglomerate areas of gram positive Actinomyces. Removal or biopsy of these large endobronchial masses must be done with care, because of the risk of bleeding and large airway obstruction. The cytology on bronchoalveolar lavage fluid may show Periodic acid-Schiff (PAS) positive stain, ZN negative and Gram-positive filamentous bacilli which is morphologically suggestive of Actinomycosis. Actinomyces spp is highly susceptible to beta lactam antibiotics, penicillin G, and amoxicillin. A minimum of 3-6 months is needed but up to 20 months of treatment may be needed. Early diagnosis and correct treatment can lead to a good prognosis with a low mortality.

Actinomyces sp. Presence in the Bone Specimens of Patients with Osteonecrosis of the Jaw: The Histopathological Analysis and Clinical Implication

Medication-related osteonecrosis of the jaw (MRONJ) and osteoradionecrosis (ORN) are two similar bone pathologies in the jaw with different aetiologies. Actinomycosis is a relatively rare oral infection caused by the Gram-positive anaerobe Actinomyces sp. that normally colonizes the oral cavity. Actinomycosis is associated with the pathogenesis of both the MRONJ and ORN, as evident in our cases, and not just as a superficial contaminant. The clinical and histopathological aspects of the cases treated in our centre were also reported with a review of the literature. Clinical implication on the treatment of the cases was highlighted in view of the presence of this microorganism.

Periapical Actinomycosis: A Rare Subdivision of Cervicofacial Actinomycosis, Review of the Literature, and a Case Report

Background

Periapical actinomycosis, which is reckoned as a subgroup of cervicofacial actinomycosis, is an uncommon, more indolent, less invasive, and limited type of actinomycosis infection. However, it can be considerably underreported due to the low number of periapical surgical specimens that are submitted for histopathological analysis after excision of the lesion with the preliminary diagnosis of typical periapical infections. It is believed that during root canal treatment, the organisms are displaced from the oral cavity into the periapical regions as a result of failure to establish aseptic techniques which can further result in actinomycosis infections and, in rare instances, lead to more severe events and can even be life-threatening. Case Presentation. We intend to report a case of periapical actinomycosis in a 34-year-old female who presented with the chief complaint of pain and slight mobility of the mandibular right second premolar and first molar with no significant issues in the patient's medical history. Initial orthopantomography revealed a uniloculated, radiolucent lesion engulfing the apices of the aforementioned teeth. An incisional biopsy was then obtained which revealed fragments of fibroconnective tissue including few crushed bone particles severely infiltrated by acute inflammatory cells and some foamy macrophages. The suppurative exudate focally surrounds colonies of filamentous bacteria as round basophilic masses with radial configuration resembling “sulfur granules.” Surgical approach consisted of curettage accompanied with peripheral ostectomy and cautious burnishing of the two involved tooth roots.

Conclusion

This case report emphasizes the importance of aseptic techniques during endodontic and more invasive treatments, as they can cause penetration of Actinomyces into the periapical region which in some cases can lead to more serious complications and even life-threatening situations.

Disseminated cutaneous Actinomyces bovis infection in an immunocompromised host: case report and review of the literature

Background

Actinomycosis is an uncommon endogenous bacterial infection caused by Actinomyces species, characterized by the development of abscesses, tissue fibrosis, and fistulisation. It remains a diagnostic challenge, due to its similarities with diverse aetiologies’ presentation, such as neoplasms, tuberculosis, or fungal infections. Actinomyces bovis is a microorganism rarely reported as a cause of human disease. Cutaneous involvement is sporadic. In this case, Actinomyces bovis was responsible for disseminated cutaneous disease in an immunosuppressed patient.

Case presentation

We report the case of a 69-year-old female with multiple skin masses, under immunosuppressive therapy due to ulcerative colitis. Imaging exams were compatible with multiple cutaneous abscesses in the cervicofacial region and limbs. Actinomyces bovis was isolated in culture after abscess drainage. Antimicrobial therapy with parenteral penicillin G and oral amoxicillin was administered for 6 months, with complete resolution of cutaneous lesions and no relapse of the infection.

Conclusions

Considering actinomycosis as a possible diagnosis in the presence of subacute/chronic recurrent mass-like cutaneous lesions, especially in the setting of immunosuppression, may reduce the burden associated with delayed diagnosis and incorrect treatment and provide better outcomes and improvement of patient’s quality of life.

Targeted histological evaluation shows high incidence of actinomyces infection in medication-related osteonecrosis of the jaws

Medication-Related Osteonecrosis of the Jaws (MRONJ) is a difficult-to-treat complication of the therapy of osteoporosis and some malignancies cured with bisphosphonates and antiresorptive drugs. The pathomechanism is unclear, but there is increasing observation that Actinomyces infection may play a role in its development and progression. The aim of our study was to demonstrate that histological examination using a validated triple staining procedure for Actinomyces bacteria strains can detect a high rate of Actinomyces infection in patient's samples with MRONJ. 112 previously hematoxylin-eosin (HE) stained samples submitted with the clinical diagnosis of MRONJ were re-evaluated histologically using an appropriate triple special staining validated for the identification of Actinomyces infection. During the first evaluation, when pathologists did not specifically look for Actinomyces, only 8.93% of the samples were reported as positive. In contrast, re-evaluation with triple staining provided a yield of 93.7% positive samples, therefore, we suggest the triple special staining to be standard in MRONJ histology evaluation. These results show that if the clinician suspects Actinomyces infection and brings this to the attention of the pathologist, it could significantly increase the number of correct diagnoses. It serves as an aid for clinicians in therapeutic success of MRONJ by selecting a long-term adequate antibiotic medication which is suitable for the elimination of actinomyces infection.

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.

Oral and Maxillo-Facial Manifestations of Systemic Diseases: An Overview

Many systemic (infective, genetic, autoimmune, neoplastic) diseases may involve the oral cavity and, more generally, the soft and hard tissues of the head and neck as primary or secondary localization. Primary onset in the oral cavity of both pediatric and adult diseases usually represents a true challenge for clinicians; their precocious detection is often difficult and requires a wide knowledge but surely results in the early diagnosis and therapy onset with an overall better prognosis and clinical outcomes. In the current paper, as for the topic of the current Special Issue, the authors present an overview on the most frequent clinical manifestations at the oral and maxillo-facial district of systemic disease.

[Cervicofacial actinomycosis]

Actinomycosis is an infectious disease caused by gram-positive, facultative anaerobic bacteria, which in most cases manifests itself in the cervicofacial area and often has a dentogenic focus. The clinical presentation ranges from acute abscess to chronically fistulating soft tissue processes. Early diagnosis and an appropriate therapeutic approach including a combination of extensive antibiotic treatment and, if necessary, surgical intervention are critical. This article presents five cases of actinomycete infections, which are intended to illustrate the variety of clinical presentations, the problems on the way to the correct diagnosis and possible therapeutic courses.

Invasive Nocardiosis: Disease Presentation, Diagnosis and Treatment - Old Questions, New Answers?

Nocardia spp. is an environmental filamentous Gram-positive bacterium that may cause infections in humans and, despite recent progress, many challenges remain regarding the management of nocardiosis. This review aims at describing most recently published data regarding the diagnosis, treatment and follow-up of patients with invasive nocardiosis. As nocardiosis mainly affects patients with cell-mediated immunity defects, a comprehensive workup is mandatory in case of invasive nocardiosis occurring in ”apparently healthy patients”. Indeed, invasive nocardiosis might reveal an unknown primary immunodeficiency or the presence of anti-GM-CSF autoantibodies. Even if the diagnosis of nocardiosis mostly relies on direct examination and bacterial culture, a genus-specific PCR may be used for the detection of Nocardia, when directly performed on a clinical sample. Brain imaging should always be performed, even in the absence of neurological symptoms. Cotrimoxazole (trimethoprim/sulfamethoxazole), linezolid, parenteral cephalosporins, carbapenems and amikacin may be used as initial antibiotics to treat nocardiosis. Cotrimoxazole or linezolid can be used as monotherapy in selected patients without brain involvement. Although treatment duration has historically been set to at least 6 months in the absence of central nervous system involvement, shorter durations (<120 days) seem to be associated with a favourable outcome.

The Pathogenic Role of Actinomyces spp. and Related Organisms in Genitourinary Infections: Discoveries in the New, Modern Diagnostic Era

Actinomycosis is a chronic, suppurative, granulomatous infectious disease, caused by different species of Actinomyces bacteria. To date, 26 validly published Actinomyces species have been described as part of a normal human microbiota or from human clinical specimens. Due to the rapid spread of new, modern diagnostic procedures, 13 of 26 of these species have been described in this century and the Actinomycetaceae family has undergone several taxonomic revisions, including the introduction of many novel species termed Actinomyces-like organisms (ALOs). There is scarce data available on the role of these novel bacterial species in various infectious processes in human medicine. The aim of this review is to provide a comprehensive overview of Actinomyces and closely related organisms involved in human diseases-with a special focus on newly described species-in particular their role in genitourinary tract infections in females and males.

Cyto-morphological and clinical approach to infections presenting with discharging sinuses mimicking malignancy

INTRODUCTION

Discharging sinuses is a form of chronic unhealed infection that can present at any site due to a variety of infectious organisms. These discharging sinuses may be associated with mass lesions and lymphadenopathy to mimic some neoplastic processes. Identifying these infections with accuracy and promptness is essential, as the treatment regimens are specific. Fine-needle aspiration (FNA) of these lesions, along with appropriate cytochemical stains, aids in the rapid and precise diagnosis of these infections and excludes neoplasms at these sites. Also, material for culture and other studies can be obtained by FNA.

MATERIAL AND METHODS

This retrospective study was conducted in the Department of pathology from 2018 to 2020. A total of 179 patients with similar clinical presentation and confirmed infection on cytology were identified. On the evaluation of the requisition forms, 32 (18%) patients were identified with discharging sinus associated along with swelling.

RESULTS

The five infections (32 cases) that were identified, included 18 cases of tuberculosis (56.25%) followed by 9 cases of actinomycosis (28.12%), 3 cases of pheohypomycosis (9.37%), and one case each of Nocardia (3.12%) and eumycetoma (3.12%) which presented as swelling with discharging sinus. Special stains were performed in all cases for confirmation. Histopathological/Microbiological correlation was done whenever available.

CONCLUSION

Infections presenting as swelling with discharging sinuses mimicking malignancy can be diagnosed on FNAC with good accuracy.

Development of a multispecies periodontal biofilm model within a stirred bioreactor

The objective of this work was to develop a subgingival biofilm model using a stirred bioreactor. Discs of bovine teeth were adapted to a stirred bioreactor filled with a culture medium containing bacterial species associated with periodontal health or disease. After anaerobic incubation, the biofilms growing on the substratum surfaces were collected and analyzed. The mean number of Colony-forming Units (CFUs) varied, but with no difference between 3 and 7 days of biofilm formation (p > 0.05). Scanning Electron Microscopy (SEM) analysis showed a uniform biofilm layer covering the cement layer of the root surface containing bacteria with diverse morphology. In checkerboard DNA-DNA hybridization, bacterial species were identified in both biofilms. In conclusion, a subgingival biofilm model was developed using a stirred bioreactor, allowing the in vitro reproduction of complex microbial communities. This is an advanced model that may be useful to mimic complex clinical periodontal biofilms.

Actinomycotic Osteomyelitis of the Hand and Wrist Treated with Pharmacotherapy Alone: A Case Report

CASE

Primary infection by Actinomyces is uncommon because susceptibility to infection requires breakdown of the normal protective mucosal barrier. Furthermore, involvement of the upper extremity is rare. This case report presents clinical, radiological, and pathological findings in a 26-year-old patient with actinomycosis of the hand that was treated successfully by pharmacotherapy alone without any surgical debridement.

CONCLUSION

Primary actinomycoses of the hand and upper extremity present as a challenging condition. It requires a high index of clinical suspicion and histopathologic diagnosis to guide treatment, typically involving antimicrobial therapy. This case highlights the usefulness of conservative treatment with antimicrobial therapy without surgical debridement.

The incidence of anaerobic bacteria in adult patients with chronic sinusitis: A prospective, single-centre microbiological study

INTRODUCTION

Chronic sinusitis caused by anaerobes is a particular concern clinically, because many of the complications are associated with infections caused by these organisms. The aim of this study was to evaluate the incidence of anaerobic bacteria in chronic sinusitis in adults as a part of a prospective microbiological study.

MATERIALS AND METHODS

Over a one-year period, aspirations of maxillary sinus secretions and/or ethmoid cavities were derived in n = 79 adult patients with chronic sinusitis by endoscopy in a tertiary-care teaching hospital in Hungary. The qualitative and quantitative compositions of the total cultivable aerobic and anaerobic bacterial and fungal flora cultured on the samples were compared. Correct anaerobic species level identifications were carried out according to standard methods.

RESULTS

Bacteria were recovered for all of the 79 aspirates and the numbers of the significant cultured isolates (with colony forming units ≥103) were between 1 and 10. A total of 206 isolates, 106 anaerobic and 100 aerobic or facultative-anaerobic strains were isolated. The most common aerobic bacteria were Streptococcus pneumoniae (n = 40), Haemophilus influenzae (n = 29), Moraxella catarrhalis (n = 6), Staphylococcus aureus (n = 7) and Streptococcus pyogenes (n = 6). The anaerobic bacteria included black-pigmented Prevotella spp. and Porphyromonas spp. (n = 27), Actinomyces spp. (n = 13), Gram-positive anaerobic cocci (n = 16), Fusobacterium spp. (n = 19) and Cutibacterium acnes (n = 8).

CONCLUSIONS

This study illustrates the microbial dynamics in which anaerobic and aerobic bacteria prevail and highlights the importance of obtaining cultures from patients with chronic sinusitis for guidance in selection of proper antimicrobial therapy.

Relevance of anaerobic bacteremia in adult patients: A never-ending story?

Obligate anaerobic bacteria are considered important constituents of the microbiota of humans; in addition, they are also important etiological agents in some focal or invasive infections and bacteremia with a high level of mortality. Conflicting data have accumulated over the last decades regarding the extent in which these pathogens play an intrinsic role in bloodstream infections. Clinical characteristics of anaerobic bloodstream infections do not differ from bacteremia caused by other pathogens, but due to their longer generation time and rigorous growth requirements, it usually takes longer to establish the etiological diagnosis. The introduction of matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) has represented a technological revolution in microbiological diagnostics, which has allowed for the fast, accurate and reliable identification of anaerobic bacteria at a low sample cost. The purpose of this review article is to summarize the currently available literature data on the prevalence of anaerobic bacteremia in adults for physicians and clinical microbiologists and to shed some light on the complexity of this topic nowadays.

Utility of Photodynamic Therapy in Dentistry: Current Concepts

The significant growth in scientific and technological advancements within the field of dentistry has resulted in a wide range of novel treatment modalities for dentists to use. Photodynamic therapy (PDT) is an emerging, non-invasive treatment method, involving photosensitizers, light of a specific wavelength and the generation of singlet oxygen and reactive oxygen species (ROS) to eliminate unwanted eukaryotic cells (e.g., malignancies in the oral cavity) or pathogenic microorganisms. The aim of this review article is to summarize the history, general concepts, advantages and disadvantages of PDT and to provide examples for current indications of PDT in various subspecialties of dentistry (oral and maxillofacial surgery, oral medicine, endodontics, preventive dentistry, periodontology and implantology), in addition to presenting some images from our own experiences about the clinical success with PDT.

Diagnosis and Management of Cervicofacial Actinomycosis: Lessons from Two Distinct Clinical Cases

Members of the Actinomyces genus are non-spore-forming, anaerobic, and aerotolerant Gram-positive bacteria that are abundantly found in the oropharynx. They are the causative agents of actinomycosis, a slowly progressing (indolent) infection with non-specific symptoms in its initial phase, and a clinical course of extensive tissue destruction if left untreated. Actinomycoses are considered to be rare; however, reliable epidemiological data on their prevalence is lacking. Herein, we describe two representative and contrasting cases of cervicofacial actinomycosis, where the affected patients had distinctively different backgrounds and medical histories. Identification of the relevant isolates was carried out using matrix-assisted laser desorption/ionization mass spectrometry; antimicrobial susceptibility was performed using E-tests. Cervicofacial actinomycoses are the most frequent form of the disease; isolation and identification of these microorganisms from relevant clinical samples (with or without histological examination) is the gold standard for diagnosis. The therapy of these infections includes surgical debridement and antibiotic therapy, mainly with a penicillin-derivative or clindamycin.

Extraintestinal Clostridioides difficile Infections: Epidemiology in a University Hospital in Hungary and Review of the Literature

Extraintestinal manifestations of Clostridioides difficile infections (CDIs) are very uncommon, and according to the literature, poor outcomes and a high mortality have been observed among affected individuals. The objective of this study was to investigate the incidence rate of extraintestinal infections caused by C. difficile (ECD) in a tertiary-care university hospital in Hungary. During a 10-year study period, the microbiology laboratory isolated 4129 individual strains of C. difficile; among these, the majority were either from diarrheal fecal samples or from colonic material and only n = 24 (0.58%) were from extraintestinal sources. The 24 extraintestinal C. difficile isolates were recovered from 22 patients (female-to-male ratio: 1, average age: 55.4 years). The isolates in n = 8 patients were obtained from abdominal infections, e.g., appendicitis, rectal abscess or Crohn’s disease. These extraintestinal cases occurred without concomitant diarrhea. In all, but two cases C. difficile was obtained as a part of a polymicrobial flora. Our isolates were frequently toxigenic and mostly belonged to PCR ribotype 027. Resistance to metronidazole, vancomycin, clindamycin and rifampin were 0%, 0%, 20.5% and 9.7%, respectively. The increasing amount of reports of C. difficile extraintestinal infections should be noted, as these infections are characterized by a poor outcome and high mortality rate.