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.

Microbiological Characterization of Actinotignum schaalii Strains Causing Invasive Infections during a Multiyear Period in a Large Canadian Health Care Region.

Actinotignum schaalii is an underrecognized Gram-positive bacillus that is associated with urinary tract infections and cutaneous abscesses. The role of A. schaalii in invasive infections continues to be unappreciated because the bacteria can be isolated from a diverse spectrum of clinical specimens, ranging from being a single pathogen in urine and blood cultures to being deemed a colonizer in polymicrobial anaerobic cultures of sterile fluids and tissues. We conducted a microbiological analysis of clinical isolates obtained from 2012 through 2019. A total of 86 isolates were analyzed; 37 (43%) were from blood cultures, 35 (41%) were from deep wounds and abscesses, 6 (7%) were from urine samples, and the rest were recovered from peritoneal, kidney, and scrotal fluid samples. Urinary tract infections were clinically identified as the source of most cases of bacteremia, although no simultaneous urine cultures yielded positive results. The 16S rRNA gene sequences were available for 32 isolates (37%). Phylogenetic analysis revealed that AS.1/AS.2 strains caused a larger proportion of bloodstream infections (BSIs) (100% versus 52% [P = 0.01]) and trended toward a higher rate of hospitalization (91% versus 76% [P = 0.18]) but had a lower clindamycin MIC90 (0.12 versus >256 µg/mL). Our study emphasizes the emergence of A. schaalii as a pathogen in human urine samples, BSIs, and skin and soft tissue infections. It highlights the pitfalls of current laboratory methods in recovering and identifying this organism from clinical specimens, particularly urine samples. Phylogenetic analysis showed unique genotypic sequences for A. schaalii AS.1/AS.2 strains causing urosepsis, which requires further study to identify potential virulence factors. IMPORTANCE Actinotignum schaalii is an underrecognized Gram-positive bacillus due to its special growth requirements and prior phenotypic identification methods, and it is often mistaken as a contaminant. It has been associated with various clinical syndromes, from urinary tract infections to cutaneous infections. The widespread use of molecular diagnostic methods allowed for improved detection. However, its role in invasive infections remains underappreciated. We conducted a detailed microbiological analysis to improve our understanding of this organism's genotypic and phenotypic characteristics. Our results highlight the pitfalls of clinical laboratory recovery, particularly from urine cultures. Although most BSIs were caused by urinary tract infections, no simultaneous urine cultures identified A. schaalii, largely due to the failure of phenotypic methods to reliably isolate and identify this organism. Additionally, this is the first study demonstrating A. schaalii strains with differences in clinical and microbiological characteristics, raising the possibility of potential bacterial virulence factors contributing to invasive infections.

Characterizing Actinotignum schaalii infections in a large Canadian healthcare region.

Aims: We characterize the epidemiology of Actinotignum schaalii within a large Canadian region after implementation of improved identification methods. Patients & methods: Positive cultures for A. schaalii from a centralized microbiology laboratory in Canada were analyzed. Clinical data were retrieved through administrative databases and chart reviews. Primary outcome was incidence of A. schaalii infections; secondary outcomes included mortality, hospital admission and length of stay. Results & conclusions: 86 unique isolates were studied, 37 bloodstream infections (BSI) and 49 non-BSIs. Patients with BSIs were older with more comorbidities, with urinary tract infections implicated as the most frequent source; skin abscesses caused the most non-BSIs. Hospitalization and 90-day mortality was higher in the BSI group. A. schaalii is an important community-acquired pathogen with the potential to cause invasive infections.

Actinotignum schaalii bacteria require special conditions and substances for their growth. Normally, A. schaalii reside in the urogenital tract without causing harm; however, they can be associated with urinary tract infections. Severe infections are increasingly identified with improved identification methods. This retrospective study included all positive cultures for A. schaalii from a centralized microbiology laboratory in Canada from 2012 to 2019. Eighty-six unique isolates were studied, including 37 bloodstream infections (BSIs) and 49 non-BSIs. The mean incidence rate of infections increased during the study. BSIs were seen in older men with other medical comorbidities and were associated with high hospitalization and mortality. Skin and soft-tissue infections comprised the majority of non-BSIs, occurring in younger patients and who had better clinical outcomes. Our population-based study of A. schaalii infections highlights the potential of this pathogen to cause severe infections.

A 2-Year Retrospective Case Series on Isolates of the Emerging Pathogen Actinotignum schaalii from a Canadian Tertiary Care Hospital.

(1) Background: Actinotignum schaalii is an emerging, opportunistic pathogen often linked with UTIs but can extend beyond the urogenital system. Data on the clinical significance of A. schaalii are still emerging. (2) Methods: A retrospective review of A. schaalii isolates in a Canadian tertiary care hospital was conducted. The clinical data of patients that grew A. schaalii from January 2020 to 2022 were documented. Demographics, site, management, and microbiological parameters surrounding culture and sensitivities were recorded. (3) Results: A total of 43 cases of A. schaalii were identified. Actinotignum schaalii was primarily involved in UTIs (n = 17), abscesses (n = 9), bacteremia (n = 6), septic arthritis (n = 5), and ulcers (n = 5). A. schaalii had a slight predilection for polymicrobial infections (51.1%, n = 22 out of 43), with Aerococcus urinae (n = 5) being the most common coisolate. Susceptibility testing was only performed in two cases that showed sensitivity to beta-lactam antibiotics and resistance to metronidazole and ciprofloxacin. Amoxicillin-clavulanate (n = 5) is the most frequently prescribed antibiotic. (4) Conclusions: The non-urogenic clinical significance of A. schaalii remains undervalued. The management of A. schaalii infection is multimodal, consisting predominantly of antimicrobials and surgical procedures specific to the etiology. Clinicians should request sensitivities for A. schaalii so that appropriate antimicrobial coverage can be provided.

Actinotignum schaalii subcutaneous abscesses in a patient with hidradenitis suppurativa: Case report and literature review.

Actinotignum schaalii (formerly Actinobaculum schaalii) is a Gram-positive, facultative anaerobic rod that is typically involved in urinary tract infections in elderly patients or those with underlying urological pathologies. In contrast, abscess formation caused by A. schaalii is very rare. We present a case of multiple abscesses in the perineal area in a young patient with hidradenitis suppurativa associated with A. schaalii and Prevotella melaninogenica and review the relevant literature on the topic.

Recurrent obstructive acute pyelonephritis: A rare form of Actinotignum (Actinobaculum) schaalii infection in a HIV-1 infected patient.

Actinobaculum schaalii is a rarely reported, anaerobic, Gram-positive bacterium which role as uropathogen is emerging. We report here the case of a 47 year old HIV-1 infected woman presented with five recurrent episodes of obstructive pyelonephritis in the context of multiple renal stones. No bacteria was found until the fifth episode, during which prolonged urinary cultures as well as 16S rDNA sequencing allowed the diagnosis of A. schaalii infection. She had developed a life-threatening condition with severe renal failure. A right nephrectomy was performed and found that the intrarenal stones were attributed to the antiretroviral therapy. The renal parenchyma corresponded to an end-stage renal disease with chronic pyelonephritis without abcesses or granules. The situation improved after six months of amoxicillin therapy.

Actinotignum (formerly Actinobaculum) schaalii: a review of MALDI-TOF for identification of clinical isolates, and a proposed method for presumptive phenotypic identification.

Actinotignum schaalii is a recognised cause of urinary tract infection. Following a case of urosepsis, 20 isolates of A. schaalii were collected over an initial 18 month period from urine and blood culture. An additional 25 isolates were collected over the following 13 months. Actinotignum schaalii had likely been overlooked or dismissed as a contaminant in our laboratory prior to this study period. It grows slowly on blood agar with supplemental CO2 or anaerobically. It may not grow on MacConkey agar or chromogenic agars used for routine urine culture. Repeated attempts at identification by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) may be required as the optimal age of cultures for testing is unclear. Utilising its characteristic antibiogram may assist phenotypic identification of this organism which is otherwise difficult to distinguish from other actinomycetes.

Actinobaculum schaalii: A truly emerging pathogen?: Actinobaculum schaalii: un pathogène réellement émergent?

Actinobaculum schaalii is a Gram-positive facultative anaerobe bacillus. It is a commensal organism of the genitourinary tract. Its morphology is nonspecific. Aerobic culture is tedious, and identification techniques have long been inadequate. Thus, A. schaalii has often been considered as a nonpathogen bacterium or a contaminant. Its pathogenicity is now well described in urinary tract infections, and infections in other sites have been reported. This pathogen is considered as an emerging one following the growing use of mass spectrometry identification. In this context, the aim of our study was to evaluate the number of isolations of A. schaalii before and after the introduction of mass spectrometry in our hospital and to study the clinical circumstances in which isolates were found.

Actinobaculum schaalii est un bacille à Gram positif anaérobie facultatif. Il s'agit d'un germe commensal du tractus génito-urinaire. Sa morphologie est aspécifique. La culture est fastidieuse en aérobiose et les techniques d'identification ont longtemps été insuffisantes. De ce fait, il a souvent été considéré comme un germe non pathogène ou un contaminant. Sa pathogénicité est aujourd'hui bien décrite dans les infections urinaires, mais des infections au niveau d'autres sites ont été rapportées. Ce pathogène considéré comme émergent, voit en réalité son nombre d'isolats augmenter depuis l'introduction de la spectrométrie de masse. Dans ce contexte, le but de notre étude est d'évaluer le nombre d'isolements d'Actinobaculum schaalii avant et après l'introduction de la spectrométrie de masse dans notre centre hospitalier et d'étudier les circonstances cliniques dans lesquelles ces isolats ont été retrouvés.

Actinobaculum schaalii, a new cause of knee prosthetic joint infection in elderly.

Actinobaculum schaalii is an emerging pathogen particularly involved in urinary tract infection of elderly people and/or patient with urological risk factors of urinary tract infection. This microorganism is a difficult-to-diagnose pathogen and is rarely involved in systemic or deep infections. Here, we report the first case of prosthetic joint infection due to A. schaalii in an 84-year-old man with a benign prostatic hyperplasia associated with chronic retention of urine. This case underlines the importance to optimize the diagnosis of emerging uropathogens as A. schaalii, to prevent systemic infections, particularly in patients with orthopaedic implants.

A validation of the Danish microbiology database (MiBa) and incidence rate of Actinotignum schaalii (Actinobaculum schaalii) bacteraemia in Denmark.

Actinotignum schaalii (former named Actinobaculum schaalii) can cause urinary tract infections (UTIs) and bacteraemia, mainly in the elderly. A. schaalii is difficult to identify with conventional biochemical tests, and it is often overlooked if the urine is only cultured in ambient air. The aim of this study was to validate data from the nationwide Danish microbiology database (MiBa) with data from the laboratory information system (LIS) at the local department of microbiology in Viborg-Herning, and to evaluate the incidence rate of bacteraemia caused by A. schaalii in Denmark by using data from the MiBa. All departments of microbiology in Denmark report data to the MiBa. All microbiological samples with A. schaalii in Denmark were extracted for a period of 5 years from the MiBa and from the local LISs. All data obtained from our local LIS were also found in the MiBa, except for data on real-time PCR, which were not registered, owing to missing ID codes in the MiBa. From 2010 to 2014, there was a significant increase in the incidence rate of blood cultures with A. schaalii, from 1.8 to 6.8 cases per million, which was probably due to coincident implementation of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) in routine diagnostics. We found that A. schaalii caused bacteraemia and UTIs mainly in the elderly. In conclusion, the MiBa can be a useful source of nationwide microbiological data in Denmark. Our results suggest that the incidence rate of A. schaalii as a cause of bacteraemia has been underestimated, and that culture of urine in CO2 can improve the detection of A. schaalii.

Actinobaculum schaalii bacteremia: A report of two cases.

We report two cases of bacteremia with Actinobaculum schaalii, a rarely reported, anaerobic, Gram-positive bacterium. The first case was a patient with renal cancer who developed pyelonephritis after cryoablation, and the second was a patient who developed sepsis after a urogenital procedure. Bacteremia resolved after administration of empiric antibiotic therapy.

Actinobaculum schaalii: identification with MALDI-TOF.

Actinobaculum schaalii is an emerging uropathogen. So far, its identification has been performed with 16S rRNA gene sequencing or PCR. The diagnosis has often been delayed due to fastidious growth and identification problems. Eleven clinical isolates of A. schaalii from bloodstream infections that were initially identified with 16S rRNA sequencing analysis were recovered and later identified with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF). We present a review of bacteriological data of these patients, an algorithm for fast laboratory work-up and advocate the use of sensitized culture of urine to allow better recovery of A. schaalii in susceptible patients.

Skin and soft-tissue infections caused by Actinobaculum schaalii: report of two cases and literature review.

Skin and soft-tissue infections (SSTIs) caused by Actinobaculum spp. are very rare. In the present study, we report two cases and review the literature. The first case was an immunocompromised patient with an extensive cellulitis secondary to an inguinal abscess, and the second case was a patient with a pilonidal abscess. Clinical outcomes of both patients were good after surgical drainage and treatment with cloxacillin. The review of the literature showed that SSTIs caused by Actinobaculum spp. are usually located on the perineal and inguinal regions and can be severe, particularly in immunocompromised patients. SSTIs caused by Actinobaculum spp. can be overlooked because identification is often difficult and they can be considered as contaminants.

Bacteraemia caused by Actinobaculum schaalii: An overlooked pathogen?

Actinobaculum schaalii is a uropathogen resistant to ciprofloxacin and trimethoprim-sulfamethoxazole. It requires a long culture time and specific conditions, and is therefore easily overgrown by other bacteria and regarded as part of the normal bacterial flora. We review 17 cases of A. schaalii bacteraemia, demonstrating its invasive potential. A. schaalii should always be ruled out as causative agent in patients with urinary tract infection or urosepticaemia with treatment failure.

A rare case of histopathological bladder necrosis associated with Actinobaculum schaalii: the incremental value of an accurate microbiological diagnosis using 16S rDNA sequencing.

We describe here a rare case of bladder wall necrosis associated with Actinobaculum schaalii in a 72-year-old patient with non-muscle-invasive bladder cancer (NMIBC). A. schaalii microbiological diagnosis requires high index of suspicion and accurate identification methods such as 16S rDNA sequencing or MALDI-TOF Mass spectrometry.

Actinobaculum schaalii, a commensal of the urogenital area.

UNLABELLED: WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Actinobaculum schaalii is considered to be a part of the normai flora in the genital and urinary tract area. It has been associated to urinary tract infection (UTI), sepsis, osteomyelitis, endocarditis and Foumier's gangrene. So far it has mainly been isolated from urine, blood and pus, and predominantly in elderly patients. This study examined the habitat of A. schaalii by collecting samples from skin and urine in patients with kidney or ureter stones before and after treatment with Extracorporeal Shock Wave Lithotripsy (ESWL). Additionally faeces and vaginal swabs from routine specimen in patients not undergoing ESWL and without known urinary calculi were also analysed. The study does not find A. schaalii in faeces but shows it to be presents on skin and mucosa in the genital area. A. schaalii is also shown a possible pathogen in the stone-patient group undergoing ESWL. OBJECTIVE: To study the habitat of Actinobaculum schaalii by examing groin swabs, faeces samples and vaginal swabs, and to determine whether it is a common uropathogen in patients with kidney or ureter stones. PATIENTS AND METHODS: A quantitative real-time PCR assay was used to analyse all samples, which were collected between 2010 and 2011. A total of 38 patients (24 men and 14 women), with kidney or ureter stones and undergoing extracorporeal shock wave lithotripsy (ESWL), provided urine samples and had groin swabs taken. In addition, 30 faecal samples and 19 vaginal swabs that had been sent for routine microbiological examinations from patients outside the ESWL group were analysed. A chi-squared test was used to analyse the differences between patient groups, studying samples from urine, faeces samples, groin swabs and vaginal swabs. RESULTS: Actinobaculum schaalii was found in the urine samples from 14 (37%) patients undergoing ESWL, and in both urine and groin swabs from seven (18%) patients. Actinobaculum schaalii was not found in faeces samples but it was found in six (32%) of the vaginal swabs, predominantly in patients >50 years (P = 0.06). CONCLUSION: The study indicates that A. schaalii is a commensal found on skin, urine and vaginal mucosa in the human urogenital area and supports other investigations in its finding that the elderly are at greatest risk of being colonized with A. schaalii.