Antimicrobial susceptibility of clinical isolates of Actinomyces and related genera reveals an unusual clindamycin resistance among Actinomyces urogenitalis strains

Isolation and Genomic Characterization of Schaalia turicensis from a Patient with Gonococcal Urethritis, Thailand

Schaalia turicensis is facultative anaerobic Gram-positive bacillus that commonly inhabits the oropharynx, gastrointestinal, and genitourinary tract of healthy individuals. This organism has been co-isolated with Neisseria gonorrhoeae from 15-year-old Thai male patient with gonococcal urethritis in Bangkok, Thailand. In this study, we characterized the class 1 integron in S. turicensis isolate using whole-genome sequencing and bioinformatics analysis. Sequencing analysis confirmed the presence of an imperfect class 1 integron located on chromosome and a novel 24.5-kb-long composite transposon, named Tn7083. The transposon Tn7083 carried genes encoding chloramphenicol resistance (cmx), sulfonamide resistance (sul1), and aminoglycoside resistance [aph(6)-Id (strB), aph(3'')-Ib (strA), aph(3')-Ia].

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.

Fabrication of Ciprofloxacin-Immobilized Calcium Phosphate Particles for Dental Drug Delivery

Calcium phosphate (CaP) particles immobilizing antibacterial agents have the potential to be used as dental disinfectants. In this study, we fabricated CaP particles with immobilized ciprofloxacin (CF), a commonly prescribed antibacterial agent, via a coprecipitation process using a supersaturated CaP solution. As the aging time in the coprecipitation process increased from 2 to 24 h, the CaP phase in the resulting particles transformed from amorphous to low-crystalline hydroxyapatite, and their Ca/P elemental ratio, yield, and CF content increased. Despite the higher CF content, the particles aged for 24 h displayed a slower release of CF in a physiological salt solution, most likely owing to their crystallized matrix (less soluble hydroxyapatite), than those aged for 2 h, whose matrix was amorphous CaP. Both particles exhibited antibacterial and antibiofilm activities along with an acid-neutralizing effect against the major oral bacteria, Streptococcus mutans, Porphyromonas gingivalis, and Actinomyces naeslundii, in a dose-dependent manner, although their dose-response relationship was slightly different. The aging time in the coprecipitation process was identified as a governing factor affecting the physicochemical properties of the resulting CF-immobilized CaP particles and their functionality as a dental disinfectant.

Case report: A rare case of skin abscess caused by coinfection of Actinobaculum schaalii and Actinomyces turicensis

Skin abscess is one of the most common infections of the skin and soft tissues. However, anaerobic bacteria are infrequently identified as the causative agents of this particular form of abscess. In this case, a 34-year-old pregnant woman was diagnosed with a skin abscess with the use of ultrasonography. The microbiological analysis results of the purulent fluid revealed the coinfection of Actinobaculum schaalii and Actinomyces turicensis. The patient was first treated empirically with 3 days of cefathiamidine, which resulted in no symptom improvement. Subsequently, a surgical procedure involving incision and draining was performed, with the administration of ceftriaxone. After 7 days of antibiotic intervention, the patient exhibited a satisfactory recovery. Clinicians need to be aware of other types of infections that might be attributed to Actinobaculum schaalii and Actinomyces turicensis, in addition to urinary tract infections.

Actinomyces spp. Prosthetic Vascular Graft Infection (PVGI): A Multicenter Case-Series and Narrative Review of the Literature

BACKGROUND

Actinomycosis represents a challenging and under-reported complication of vascular surgery. Optimal management of Actinomyces spp. prosthetic vascular graft infection (PVGI) is highly uncertain because of the paucity of reports on this disease.

METHODS

We conducted a retrospective case-series of Actinomyces-PVGI that occurred in the last five years in two major university hospitals in northern Italy. We searched for previously published cases in the scientific literature.

RESULTS

We report five original cases of Actinomyces spp. prosthetic vascular graft infection following aortic aneurysm repair. Our literature review retrieved eight similar cases. Most patients were immunocompetent males. Most infections were polymicrobial (11/13 cases), with a prevalence of A. odontolyticus involvement (3/13 cases were associated with. Salmonella spp. infection). All cases had a late presentation (≥4 months from graft placement), with 61% associated with an aorto-enteric fistula. All patients received antibiotic therapy, but the duration was highly heterogeneous (from two weeks to life-long antibiotics). The patients without surgical revision experienced septic recurrences (2/13), permanent dysfunction (1/13), or a fatal outcome (2/13), while of the remainder who underwent vascular graft explant, six recovered completely and one developed a periprosthetic abscess. In two cases follow-up was not available.

CONCLUSIONS

This case-series aims to raise the diagnostic suspicion and to describe the current management of Actinomyces-PVGIs. We highlight a high heterogeneity in antibiotic duration, choice of the antibiotic regimen, and surgical management. Higher reporting rate is advisable to produce better evidence and optimize management of this rare complication of vascular surgery.

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.

[Actinomyces europaeus (Gleimia europaea) associated with brain abscess: A report of three cases]

A brain abscess is a focal infection characterized by a collection of pus in the brain parenchyma. It is a life-threatening condition that should be diagnosed and treated as soon as possible. We report here three cases of patients with otogenic brain abscesses of polymicrobial origin that had in common the isolation of Actinomyces europaeus, which has not been previously described in this location. A. europaeus was identified by the conventional methodology, matrix-associated laser deionization-time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing. Antibiotic susceptibility was evaluated by the epsilometric method, and all isolates showed sensitivity to penicillin, vancomycin and linezolid, whereas susceptibility to clindamycin and erythromycin was variable. MALDI-TOF MS identification allowed a quick and reliable species level identification in order to provide a rapid and effective response to avoid treatment delay that could lead to increased morbidity and even mortality.

Recent Trends in Antimicrobial Resistance among Anaerobic Clinical Isolates

Anaerobic bacteria are normal inhabitants of the human commensal microbiota and play an important role in various human infections. Tedious and time-consuming, antibiotic susceptibility testing is not routinely performed in all clinical microbiology laboratories, despite the increase in antibiotic resistance among clinically relevant anaerobes since the 1990s. β-lactam and metronidazole are the key molecules in the management of anaerobic infections, to the detriment of clindamycin. β-lactam resistance is usually mediated by the production of β-lactamases. Metronidazole resistance remains uncommon, complex, and not fully elucidated, while metronidazole inactivation appears to be a key mechanism. The use of clindamycin, a broad-spectrum anti-anaerobic agent, is becoming problematic due to the increase in resistance rate in all anaerobic bacteria, mainly mediated by Erm-type rRNA methylases. Second-line anti-anaerobes are fluoroquinolones, tetracyclines, chloramphenicol, and linezolid. This review aims to describe the up-to-date evolution of antibiotic resistance, give an overview, and understand the main mechanisms of resistance in a wide range of anaerobes.

A first case of prosthetic joint infection with Actinomyces radingae

Prosthetic joint infection is a common clinical orthopedic problem but infections caused by Actinomyces species have been rarely reported. An increasing number of reports identifying Actinomyces in cases of prosthetic joint infection suggest it may be an emerging pathogen. We describe here the first known case of a prosthetic joint infection caused by Actinomyces radingae.

Comparative genomic analyses of the clinically-derived Winkia strain NY0527: the reassignment of W. neuii subsp. neuii and W. neuii subsp. antitratus into two separate species and insights into their virulence characteristics

Background

Winkia neuii, previously known as Actinomyces neuii, is increasingly recognized as a causative agent of various human infections, while its taxonomy and genomic insights are still understudied.

Methods

A Winkia strain NY0527 was isolated from the hip abscess of a patient, and its antibiotic susceptibility was assessed. The genome was hybrid assembled from long-reads and short-reads sequencing. Whole-genome-based analyses on taxa assignment, strain diversity, and pathogenesis were conducted.

Results

The strain was found to be highly susceptible to beta-lactam antibiotics, but resistant to erythromycin, clindamycin, and amikacin. The complete genome sequences of this strain were assembled and found to consist of a circular chromosome and a circular plasmid. Sequence alignment to the NCBI-nt database revealed that the plasmid had high sequence identity (>90%) to four Corynebacterium plasmids, with 40-50% query sequence coverage. Furthermore, the plasmid was discovered to possibly originate from the sequence recombination events of two Corynebacterium plasmid families. Phylogenomic tree and genomic average nucleotide identity analyses indicated that many Winkia sp. strains were still erroneously assigned as Actinomyces sp. strains, and the documented subspecies within W. neuii should be reclassified as two separate species (i.e., W. neuii and W. anitratus). The core genome of each species carried a chromosome-coded beta-lactamase expression repressor gene, which may account for their broadly observed susceptibility to beta-lactam antibiotics in clinical settings. Additionally, an ermX gene that expresses fluoroquinolone resistance was shared by some W. neuii and W. anitratus strains, possibly acquired by IS6 transposase-directed gene transfer events. In contrast, tetracycline resistance genes were exclusively carried by W. neuii strains. In particular, W. neuii was found to be more pathogenic than W. anitratus by encoding more virulence factors (i.e., 35-38 in W. neuii vs 27-31 in W. anitratus). Moreover, both species encoded two core pathogenic virulence factors, namely hemolysin and sialidase, which may facilitate their infections by expressing poreformation, adhesion, and immunoglobulin deglycosylation activities.

Conclusion

This study highlights the underappreciated taxonomic diversity of Winkia spp. and provides populational genomic insights into their antibiotic susceptibility and pathogenesis for the first time, which could be helpful in the clinical diagnosis and treatment of Winkia spp. infections.

Periprosthetic Joint Infection With Actinomyces radingae May Lead to the Identification of a Neglected Source of Intraoperative Contamination

Periprosthetic joint infection remains a major complication in arthroplasty. We present the first description of a case of periprosthetic joint infection with Actinomyces radingae, microorganism that is mostly found on the skin of the upper body and might cause particular challenges as it is difficult to culture and specify. Furthermore, a thorough microbiologic workup may indicate the source of infection. In this case, it is possible that perspiration from the surgeon was the source of intraoperative contamination. Intraoperative contamination through perspiration may be important and should be avoided by all means.

Infective endocarditis by Actinomyces species: a systematic review

Actinomycosis, is a slowly progressive infection that may mimic malignancy due to the invasiveness of tissues and the ability to form sinus tracts. Infective Endocarditis (IE) is a rare disease with significant morbidity and mortality. Interestingly, even though there are scarce data of IE by Actinomyces spp. in the literature, a review adequately summarizing all available evidence on the topic in a systematic way is lacking. The aim of this study was to systematically review all cases of IE by Actinomyces spp. in the literature and describe the epidemiology, microbiology, clinical characteristics, treatment and outcomes of this infection. A systematic review of PubMed, Scopus and Cochrane library (through 19 August 2021) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE by Actinomyces spp. was performed. A total of 31 studies providing data for 31 patients were included. A prosthetic valve was present in 12.9%, while the most common microorganism was A. meyeri. Aortic valve was the most commonly infected intracardiac site, followed by the mitral valve. Diagnosis was most commonly performed with transesophageal echocardiography, while the diagnosis was made at autopsy in 16.1%. Penicillin, cephalosporins and aminopenicillins were the most commonly used antimicrobials. Clinical cure was noted in 80.6%, while mortality was 19.4%. Development of heart failure was associated with mortality by IE. This systematic review thoroughly describes IE by Actinomyces and provides information on epidemiology, clinical presentation, treatment and outcomes.

Antimicrobial Susceptibility of Clinical Oral Isolates of Actinomyces spp

Actinomyces species play an important role in the pathogenesis of oral diseases and infections. Susceptibility testing is not always routinely performed, and one may oversee a shift in resistance patterns. The aim of the study was to analyze the antimicrobial susceptibility of 100 well-identified clinical oral isolates of Actinomyces spp. against eight selected antimicrobial agents using the agar dilution (AD) and E-Test (ET) methods. We observed no to low resistance against penicillin, ampicillin-sulbactam, meropenem, clindamycin, linezolid and tigecycline (0-2% ET, 0% AD) but high levels of resistance to moxifloxacin (93% ET, 87% AD) and daptomycin (83% ET, 95% AD). The essential agreement of the two methods was very good for benzylpenicillin (EA 95%) and meropenem (EA 92%). The ET method was reliable for correctly categorizing susceptibility, in comparison with the reference method agar dilution, except for daptomycin (categorical agreement 87%). Penicillin is still the first-choice antibiotic for therapy of diseases caused by Actinomyces spp.

Acute disseminated actinomycosis presenting as pneumonia with bilateral pulmonary nodules and pelvic osteomyelitis in an immunocompetent patient

Actinomycosis is an indolent human infectious disease caused by gram-positive anaerobic filamentous bacteria Actinomyces. Despite its sluggish growth, clinical manifestations can be acute or chronic. Over the last five decades, a significant incidence decline in the western world is due to the discovery of effective antimicrobials and improved oral hygiene. Actinomycosis is now rarely encountered and often misdiagnosed as its manifestations mimic malignancy and other infectious diseases. Due to prior use of antimicrobials, laboratory diagnostic processes often fail to isolate the organism making it arduous to establish the diagnosis. Clinical classification is based on the geographical distribution of the disease as oro-cervicofacial, thoracic, abdominopelvic, neurologic, musculoskeletal, and disseminated. Disseminated and pulmonary actinomycosis in an immunocompetent individual is extremely rare. Here we present a 53-year-old healthy male presenting with acute disseminated actinomycosis with bilateral pulmonary nodules, right upper lobe pneumonia, and pelvic osteomyelitis from Actinomyces odontolyticus infection.

Intravenous administration of Penicillin results in therapeutic intravitreal levels in chronic postoperative endophthalmitis

IMPORTANCE

The role of systemic antibiotics in the treatment of bacterial endophthalmitis remains controversial. While penicillin is a highly effective antibiotic against bacteria that frequently cause endophthalmitis, the ability of systemically administered Penicillin G to penetrate into the vitreous at adequate therapeutic concentrations has not been studied. Its role in the treatment of endophthalmitis, particularly for bacteria for which it is the antibiotic of choice, therefore remains unknown.

OBJECTIVE

We sought to determine whether intravenous administration of Penicillin G leads to adequate therapeutic concentrations in the vitreous for the treatment of bacterial endophthalmitis.

DESIGN AND SETTING

This study was conducted in an ambulatory setting, at the Ottawa Hospital Eye Institute, a university-affiliated tertiary care center, where a 77-year old gentleman with chronic post-cataract surgery Actinomyces neuii endophathalmitis was treated with intravenous Penicillin G (4 × 106 units every 4 h) and intravitreal ampicillin (5000μg/0.1 m1).

MAIN OUTCOMES AND MEASURES

Intravitreal concentration of Penicillin G and ampicillin were obtained at the time of intraocular lens removal, measured by high-performance liquid chromatography.

RESULTS

The intravitreal concentration of penicillin and ampicillin was 3.5μg/ml and 0.3μg/ml, respectively. Both the concentration of penicillin and ampicillin were within the level of detection of their respective assays (penicillin 0.06-5μg/ml, ampicillin 0.12-2.5μg/ml).

CONCLUSION AND RELEVANCE

This study shows that intravenous Penicillin G administered every four-hours allows for adequate intravitreal concentrations of penicillin. Future studies are required to determine if the results of this study translate into improved clinical outcomes.

[Analysis of the diversity of Actinomyces/Actinotignum clinical isolates in a university hospital]

Actinomyces and related genera are grampositive bacilli, opportunistic pathogens, which have been mainly involved in endogenous infections. However, due to the complexity in identifying them for most clinical laboratories, there is scant knowledge about their real clinical significance. In this work, 166 isolates of 13 different species of Actinomyces/Actinotignum species recovered from clinical samples of patients treated in a university hospital were studied. The identification was performed by MALDI-TOF MS and molecular identification. MALDI-TOF MS identified 91.57% of the isolates (152/166) at the species level using a score ≥ 1.7 and 3.61% (6/166) of the isolates were identified only at the gender level with a score ≥ 1.5. MALDI-TOF MS did not yield reliable identification results for 4.82% (8/166) of the isolates. Actinomyces/Actinotignum species were isolated from: soft tissue (n: 47), urine samples (n: 35), head / neck abscesses (n: 19), genital abscesses (n: 11), blood samples (n: 10), breast abscesses (n: 8), osteoarticular samples (n: 6), abdominal/ascitic fluids (n: 3), abdominal abscesses (n: 5), sputum/BAL (n: 4), brain abscesses (n: 3), and others (n: 15). The results obtained from the statistical analysis showed a high differential frequency (> 2) for the location/species association: urine/A. schaalii/sanguinis; brain abscesses/A. europaeus; osteoarticular samples/A. urogenitalis; abdominal abscesses/ A. turicensis; respiratory samples/A. naeslundii/viscosus. This information provides a greater understanding of the clinical and epidemiological relevance of these species. The pathogenic role of Actinomyces spp. will be increasingly revealed as these microorganisms could be recognized thanks to prolonged culture and the advances in identification technology facilitated by MALDI-TOF MS.

Abdominopelvic Actinomycosis Mimicking a Malignant Ovarian Neoplasia: Case Report and Review of Literature

Abdominal actinomycosis is a chronic, granulomatous, and indolent disease produced by Actinomyces spp., a gram-positive filamentous bacillus, anaerobic, commensal in the oral cavity, gastrointestinal tract, and pelvic mucosa. Diagnosis is usually difficult and delayed due to its insidious presentation. It can simulate different neoplastic, inflammatory as well as infectious diseases such as tuberculosis, nocardiosis, or mycosis. In most cases, the diagnosis is made postoperatively with the histopathological report, and only 10% of them are diagnosed preoperatively. We present two cases of abdominopelvic actinomycosis simulating advanced ovarian neoplasia.

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.

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.

A rare case of Actinomyces skin and soft tissue infection in an end-stage kidney disease patient with a review of the literature

End-stage kidney disease (ESKD) patients are a commonly overlooked immunocompromised population that places them at risk for rare infections. We describe the case of a 78-year-old man with a history of ESKD managed with thrice weekly in-center hemodialysis who had a prolonged episode of left elbow pain and drainage and was eventually found to have a skin and soft tissue infection from Actinomyces radingae. We review the bacteriology of Actinomyces spp. and the experiences of other providers who have treated actinomycosis in individuals with ESKD. The anatomic sites and demographics of these individuals are heterogeneous, but they all generally require a long antibiotic course with a beta-lactam and portend to a good prognosis. High index of suspicion is needed to identify rare and atypical infections in the ESKD population.

Antimicrobial treatment of Acinetobacter neuii invasive infections: A systematic review

Aims: The objectives of this study were to find out whether and to what extent Actinomyces neuii is pathogenic to humans in terms of causing invasive infections and to ascertain the most appropriate and effective antibiotic therapy against this bacterium. Material and method: This study was designed as a systematic review article. MEDLINE, Google Scholar, SCIndex, Cochrane database of published clinical trials - Central and Clinicaltrials.gov databases were systematically searched for primary case reports or case series describing invasive infection with Actinomyces neuii. Results: A literature search identified 23 studies that met the inclusion criteria, describing cases of patients with an invasive infection caused by Actinomyces neuii. It was found that A. neuii could cause endocarditis, endophthalmitis, osteomyelitis, pleural empyema, soft tissue abscesses, neonatal sepsis, ventriculoperitoneal shunt infections and periprosthetic tissue infections. The most prescribed antibiotics for the treatment of Actinomyces neuii infections were amoxicillin and vancomycin (n = 10; 12.3%), followed by penicillin (n =9; 11.1%), gentamicin (n = 6; 7.4%), ampicillin (n = 5; 6.2%) and ceftazidime (n = 4; 4.9%). Antibiotic treatment of infections caused by A. neuii was followed by clinical improvement or complete cure of all patients, with no recorded deaths. Conclusion: A. neuii has a relevant pathogenic potential to cause invasive infections of various organs and tissues, especially in immunocompromised individuals of any age. For the treatment of mild infections caused by this bacterium, the antibiotics of choice are penicillin or amoxicillin, while vancomycin should be used to treat severe infections caused by Actinomyces neuii.

Bacteremia and urogenital infection with Actinomyces urogenitalis following prolonged urinary retention

A case of bacteremia with the fastidious bacteria Actinomyces urogenitalis following lengthy urinary retention is reported in a sixty-year-old man. In 2013, the first case of bacteremia due to A. urogenitalis was presented, secondary to a tubo-ovarian abscess following transvaginal oocyte retrieval. To the best of our knowledge, this is the first male bacteremic episode involving A. urogenitalis related to a urinary tract focus. The patient had no prior urogenital medical history. Extensive susceptibility testing was done on isolates from urinary and blood cultures. The organism exhibited fluoroquinolone resistance but was susceptible to most other antibiotics used in the treatment of urinary infections. Due to its unusual growth requirements infections with A. urogenitalis are most likely an underdiagnosed entity.

Microbiological and Clinical Aspects of Cervicofacial Actinomyces Infections: An Overview

Similarly to other non-spore-forming Gram-positive anaerobes, members of the Actinomyces genus are important saprophytic constituents of the normal microbiota of humans. Actinomyces infections are considered to be rare, with cervicofacial infections (also known as ‘lumpy jaw syndrome’) being the most prevalent type in the clinical practice. Actinomycoses are characterized by a slowly progressing (indolent) infection, with non-specific symptoms, and additionally, the clinical presentation of the signs/symptoms can mimic other pathologies, such as solid tumors, active Mycobacterium tuberculosis infections, nocardiosis, fungal infections, infarctions, and so on. The clinical diagnosis of actinomycosis may be difficult due to its non-specific symptoms and the fastidious, slow-growing nature of the pathogens, requiring an anaerobic atmosphere for primary isolation. Based on 111 references, the aim of this review is to summarize current advances regarding the clinical features, diagnostics, and therapy of cervicofacial Actinomyces infections and act as a paper for dentistry specialists, other physicians, and clinical microbiologists.

Repetitive urinary tract infections and two prostatic masses: Prostatic soft tissue infection with Actinomyces neuii

Actinomyces infection is a tissue destructive, low-grade infection that often resembles malignancy. We report the case of a 70-year-old male with repeated, culture-negative urinary tract infections while intermittently catheterized. At presentation, the patient reported a new episode of urinary tract infection with white discharge in his urine. Transrectal ultrasonography showed two lesions in the prostate, suspect for prostate cancer. However, biopsy did not show cancer, and anaerobic culture grew Actinomyces neuii. A 3-month antibiotic course of amoxicillin eventually cured the infection. This is a case of prostatic soft tissue infection with A. neuii. It is important to consider Actinomyces infection in patients with a non-malignant prostatic mass. Although β-lactam antibiotics do not penetrate the prostate well, the Actinomyces infection was cured by prolonged amoxicillin treatment in this case. It is possible that the tissue damage enhanced the amoxicillin concentration in the infected prostate.

Antibiotic resistance genes in the Actinobacteria phylum

The Actinobacteria phylum is one of the oldest bacterial phyla that have a significant role in medicine and biotechnology. There are a lot of genera in this phylum that are causing various types of infections in humans, animals, and plants. As well as antimicrobial agents that are used in medicine for infections treatment or prevention of infections, they have been discovered of various genera in this phylum. To date, resistance to antibiotics is rising in different regions of the world and this is a global health threat. The main purpose of this review is the molecular evolution of antibiotic resistance in the Actinobacteria phylum.

Actinomyces turicensis Necrotizing Soft-Tissue Infection of the Thigh in a Diabetic Male

Background: Necrotizing soft-tissue infections are a devastating infection that is rarely caused by Actinomyces spp. Case Report: A 45-year-old obese previously healthy male presented to the emergency department with diabetic ketoacidosis. The patient developed systemic signs of infections and right medial thigh pain subsequently diagnosed as a necrotizing soft-tissue infection. Successful treatment included prompt surgical intervention and initiation of broad-spectrum antimicrobial drugs. Conclusion: Actinomyces turicensis may be the pathogen causing certain necrotizing soft-tissue infections. Clinicians should consider the possibility that this organism represents a true pathogen and not colonization/contamination.

Antimicrobial Susceptibility Patterns of Anaerobic Bacterial Clinical Isolates From 2014 to 2016, Including Recently Named or Renamed Species

BACKGROUND

Anaerobic bacterial resistance trends may vary across regions or institutions. Regional susceptibility patterns are pivotal in the empirical treatment of anaerobic infections. We determined the antimicrobial resistance patterns of clinically important anaerobic bacteria, including recently named or renamed anaerobes.

METHODS

A total of 521 non-duplicated clinical isolates of anaerobic bacteria were collected from a tertiary-care hospital in Korea between 2014 and 2016. Anaerobes were isolated from blood, body fluids, and abscess specimens. Each isolate was identified by conventional methods and by Bruker biotyper mass spectrometry (Bruker Daltonics, Leipzig, Germany) or VITEK matrix-assisted laser desorption ionization time-of-flight mass spectrometry (bioMérieux, Marcy-l'Étoile, France). Antimicrobial susceptibility was tested using the agar dilution method according to the CLSI guidelines. The following antimicrobials were tested: piperacillin-tazobactam, cefoxitin, cefotetan, imipenem, meropenem, clindamycin, moxifloxacin, chloramphenicol, tetracycline, and metronidazole.

RESULTS

Most Bacteroides fragilis isolates were susceptible to piperacillin-tazobactam, imipenem, and meropenem. The non-fragilis Bacteroides group (including B. intestinalis, B. nordii, B. pyogenes, B. stercoris, B. salyersiae, and B. cellulosilyticus) was resistant to meropenem (14%) and cefotetan (71%), and Parabacteroides distasonis was resistant to imipenem (11%) and cefotetan (95%). Overall, the Prevotella and Fusobacterium isolates were more susceptible to antimicrobial agents than the B. fragilis group isolates. Anaerobic gram-positive cocci exhibited various resistance rates to tetracycline (6-86%). Clostridioides difficile was highly resistant to penicillin, cefoxitin, imipenem, clindamycin, and moxifloxacin.

CONCLUSIONS

Piperacillin-tazobactam, cefoxitin, and carbapenems are highly active β-lactam agents against most anaerobes, including recently named or renamed species.

Gossypiboma: a ghastly find

A gossypiboma is a mass within a patient's body comprising a cotton matrix surrounded by a foreign body granuloma. We describe an unusual presentation of a gossypiboma presenting in a 32-year-old man with acute epigastric pain and haematemesis. His surgical history revealed an emergency laparotomy following a road traffic accident 16 years ago. Initial gastroscopy showed extrinsic stomach compression. An abdominal ultrasound scan followed by a CT scan evidenced a large, well-defined, predominantly cystic mass with some solid areas occupying the left hypochondrium. Conservative management with insertion of a percutaneous drain proved to be inefficient. A laparotomy was performed; intraoperatively, the cyst was found to be ruptured and within it, a large surgical gauze was found. This was removed but required a distal pancreatectomy and gastrectomy for complete excision. He was discharged on day 74 of admission with outpatient follow-up.

Actinomyces europaeus Isolated from a Breast Abscess in a Penicillin-Allergic Patient

This is a case of Actinomyces europaeus in the breast abscess of a penicillin-allergic woman. The mainstay of treatment for actinomycosis is penicillin, and there is a lack of literature describing nonpenicillin treatment options. A 69-year-old woman presented acutely with a breast abscess which was managed with incision and drainage and antibiotic therapy to good response. 21 days after presentation, Actinomyces were grown from the culture of pus, so the patient was recalled and more rigorous treatment and follow-up were initiated. The penicillin allergy led to difficulty in the identification of an appropriate antimicrobial agent that was also logistically feasible to be given on an outpatient IV basis. IV tigecycline followed by oral clarithromycin was found to be effective treatment.