[Actinotignum schaalii: Report of two cases of bacteremia in Argentina]. / Actinotignum schaalii: reporte de dos casos de bacteriemias en Argentina.

Actinotignum schaalii is an emerging pathogen in elderly patients with urinary tract pathologies. Two cases of A. schaalii bacteremia are described. Case 1: 79-year-old patient with a history of benign prostatic hyperplasia. He was admitted to the ward for febrile syndrome, abdominal pain, and dysuria. Case 2: 95-year-old patient with prostatic adenomectomy, urethrostomy due to urethral stricture, and benign prostatic hyperplasia. He was admitted due to febrile syndrome, productive cough, bilateral infiltrates with right paracardiac image, and pleural effusion. In both patients, A. schaalii was isolated in blood cultures, identified by MALDITOF-MS mass spectrometry. Only in case 1 was it confirmed that the focus of bacteremia was urinary. It is important to suspect this emerging pathogen in urinary infections with pathological sediment without developing in traditional culture media to ensure adequate empirical treatment. Since most of the isolates show resistance to ciprofloxacin and trimethoprim-sulfamethoxazole.

Significant increase in cultivation of Gardnerella vaginalis, Alloscardovia omnicolens, Actinotignum schaalii, and Actinomyces spp. in urine samples with total laboratory automation.

While total laboratory automation (TLA) is well established in laboratory medicine, only a few microbiological laboratories are using TLA systems. Especially in terms of speed and accuracy, working with TLA is expected to be superior to conventional microbiology. We compared in total 35,564 microbiological urine cultures with and without incubation and processing with BD Kiestra TLA for a 6-month period each retrospectively. Sixteen thousand three hundred thirty-eight urine samples were analyzed in the pre-TLA period and 19,226 with TLA. Sixty-two percent (n = 10,101/16338) of the cultures processed without TLA and 68% (n = 13,102/19226) of the cultures processed with TLA showed growth. There were significantly more samples with two or more species per sample and with low numbers of colony forming units (CFU) after incubation with TLA. Regarding the type of bacteria, there were comparable amounts of Enterobacteriaceae in the samples, slightly less non-fermenting Gram-negative bacteria, but significantly more Gram-positive cocci, and Gram-positive rods. Especially Alloscardivia omnicolens, Gardnerella vaginalis, Actinomyces spp., and Actinotignum schaalii were significantly more abundant in the samples incubated and processed with TLA. The time to report was significantly lower in the TLA processed samples by 1.5 h. We provide the first report in Europe of a large number of urine samples processed with TLA. TLA showed enhanced growth of non-classical and rarely cultured bacteria from urine samples. Our findings suggest that previously underestimated bacteria may be relevant pathogens for urinary tract infections. Further studies are needed to confirm our findings.

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.

Actinotignum schaalii infection: Challenges in diagnosis and treatment.

Actinotignum schaalii affects elderly people and is associated with individuals with urological-related predispositions, but can be found in a variety of locations, such as cutaneous, intraabdominal, genitourinary and surgical infections. Disseminated infections occur less frequently and are by and large related to urinary tract colonisation. This pathogen is often neglected due to growth requirements, especially in urinary tract infections. We present 107 Actinotignum schaalii isolated from genitourinary samples (80.4%), from skin and soft tissue infections (13.1%), from bone and deep tissue infection (4.7%) and from blood cultures (1.9%). The automated system Alfred 60/AST was paramount for the isolation of 77.6% of the UTI. All the isolates tested were susceptible to penicillin, ampicillin, linezolid, vancomycin, teicoplanin, rifampicin and tetracycline. In conclusion, we present a large series of Actinotignum schaalii infections. This pathogen is hard to isolate, and is resistant to commonly used empirical antimicrobials.

Actinotignum schaalii pyelonephritis in a young adult with ureteric calculus: case report.

Introduction: Actinotignum schaalii is a Gram-positive coccobacillus, and a member of the normal human microbiota. A. schaalii is considered as an emerging pathogen causing urinary tract infections among the elderly. Because of an anaerobic growth requirement and lack of knowledge on pathogenic potential following conventional microbiology laboratory techniques, A. schaalii is difficult to identify. Case report: A previously well 24-year-old male presented to a tertiary care unit with fever, left flank pain, and dysuria for two days. He was initially treated with empiric oral ciprofloxacin by the general practitioner. Following admission, blood cultures and urine cultures were done, and empirical intra-venous piperacillin-tazobactam was started. X-ray of the pelvis revealed left-sided pyelonephritis and left ureteric calculi. A nephrostomy tube was inserted to relieve the obstruction which drained pus and was sent to microbiology laboratory in aerobic and anaerobic blood culture bottles. Two days later blood culture flagged positive for Gram-positive bacilli from the anaerobic bottle, and the pus from enriched anaerobic culture grew A. schaalii. The urine culture remained negative. By VITEK 2 anaerobic card and MALDI-TOF analysis, it was identified as A. schaalii. Following clinical improvement, he was discharged with oral doxycycline. Ureteric calculus was removed and remained sterile following 16s DNA analysis. Conclusions: The urine Gram staining may have a role in detecting and considering anaerobic media to isolate A. schaalii. The novel diagnostic platforms are important to speciate the pathogen. Also, the lack of pathogen-specific breakpoints for antimicrobial susceptibilities made it a problem to decide on appropriate therapy.

Actinotignum schaalii infection - a case series from a tertiary hospital in Greece.

Introduction: Actinotignum schaalii is a small Gram-positive facultative anaerobic coccoid rod that was reclassified in 1997 from the genus Actinomyces and is difficult to culture with usual microbiological techniques, as it is slowly growing. A. schaalii is an emerging human pathogen that is most commonly implicated in urinary tract infections (UTIs), but has also been isolated less frequently from abscesses of various sites (such as the skin, the genitourinary tract, surgical sites or intraabdominal). Methods: All cases where A. schaalii was identified during a 6-year period (January 2016 - January 2022) in the University Hospital of Heraklion were reviewed. Results: A. schaalii was isolated in 11 cultures from 10 patients. The site of infection was skin and soft tissue in nine out of eleven cultures (81.8%) and the bone was the site of infection in two patients (18.2%). Most cultures were polymicrobial. The median age of patients was 55.5 years (interquartile range 34-63 years), and 80% (n=8) were male. A. schaalii was susceptible to beta-lactams, quinolones and vancomycin, but resistant to clindamycin, erythromycin and metronidazole. Moreover, two cases of diabetic patients diagnosed with polymicrobial diabetic foot osteomyelitis from this organism are presented in detail. Both patients were successfully managed with targeted antimicrobial treatment and prompt surgical management. Conclusions: A. schaalii is an emerging pathogen that is likely under-reported due to difficulties in isolation and identification. Herein two cases of diabetic foot osteomyelitis are also presented in detail, successfully managed with targeted antimicrobial therapy and surgical debridement.

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 Can Be an Uropathogen of "Culture-Negative" Febrile Urinary Tract Infections in Children with Urinary Tract Abnormalities.

Accurate diagnosis and treatment of febrile urinary tract infections (UTI) during childhood are important for the prevention of renal parenchymal damage and functional loss, and detection of underlying diseases related to chronic kidney disease (CKD). Actinotignum schaalii (A. schaalii)-related febrile UTI in children is rare, and its incidence and risk factors remain unclear. A 3-year-old boy with a history of UTI presented with fever and vomiting. Although the culture of his urine specimen in air was negative, A. schaalii was observed in a 5% carbon dioxide (CO2) culture condition, as well as an anaerobic one. A diagnosis of febrile UTI was made, and he recovered with antibiotic therapy. He was found to have CKD associated with vesicoureteral reflux (VUR) after further investigations. A. schaalii is one of the causative agents of febrile UTI in children with urinary tract abnormalities. Although the culture in the air could show negative results, urine culture in 5% CO2 and anaerobic conditions is useful for diagnosis. Our case is the youngest and the first known case of A. schaalii-related febrile UTI associated with VUR in children.

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.

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.

Presumed Septic Shock Caused by Actinotignum schaalii Bacteremia.

We herein report a case of presumed septic shock due to Actinotignum schaalii bacteremia with urinary tract infection. A 65-year-old Japanese man suffering from a fever was diagnosed with septic shock due to urinary tract infection. A urine sample was additionally incubated under 5% CO2 and anaerobic conditions after A. schaalii was identified in a blood culture, but A. schaalii was not detected in the urine culture. If Gram-positive rods are observed on Gram staining of a urine sample in symptomatic patients with a predisposing urogenital condition, 5% CO2 and an anaerobic culture of a urine sample should be performed immediately.

Case Report: Emphysematous Pyelonephritis With a Congenital Giant Ureterocele.

A 14-year-old girl noticed malodorous urine and experienced left flank pain. The patient was presented to our hospital with gradually increasing pain. She had no underlying disease but had a history of pain on micturition for several days. Hematologic examination indicated low white blood cell and platelet counts and a high serum lactate level. Computed tomography showed that a part of the parenchyma of the left kidney had poor contrast and was deteriorated, with fluid and gas retention from the perirenal region to the retroperitoneal cavity. A left hydroureter and large ureterocele were observed in the bladder. She was diagnosed with emphysematous pyelonephritis (EPN) with a giant congenital ureterocele. Vasopressors and blood transfusion failed to maintain normal circulatory dynamics, and an open left nephrectomy and transurethral ureterocele fenestration were performed. The excised outer portion of the left kidney was dissolved by the infection and replaced with blood clots and necrotic tissue. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identified the inflammatory, gas-producing bacteria Actinotignum schaalii, Peptoniphilus asaccharolyticus, and Actinomyces odontolyticus. Meropenem was administered for 4 days postoperatively and then de-escalated to sulbactam/ampicillin for another 10 days. The patient was discharged on day 17 of hospitalization, and the postoperative course remained favorable. EPN is extremely rare in pediatric patients, and it is believed that nephrectomy is sometimes necessary if the patient does not have normal circulatory dynamics despite the use of catecholamines.

Actinotignum schaalii Abscess in a Patient with Common Variable Immunodeficiency.

Actinotignum schaalii is an anaerobic, gram-positive commensal organism of the urogenital tract. A. schaalii typically causes urinary tract infections, predominantly in the elderly. Here, we describe the first case of A. schaalii infection presenting as cellulitis and abscess in a patient with common variable immunodeficiency. The patient was successfully treated with an incision and drainage and a prolonged antibiotic course. A. schaalii infection should be considered in sterile abscesses, and anaerobic cultures should be requested in the absence of positive routine cultures.

Actinotignum schaalii Infection: A Clandestine Cause of Sterile Pyuria?

Actinotignum schaalii is an underappreciated cause of urinary tract infections (UTIs) in older adults. The diagnosis may be missed due to difficulty isolating and identifying the organism. Complications can result because the organism is intrinsically resistant to 2 commonly used drugs to treat UTI, as illustrated by this case.

Actinotignum schaalii: reporte de dos casos de bacteriemias en Argentina / Actinotignum schaalii: Report of two cases of bacteremia in Argentina

Resumen Actinotignum schaalii es un patógeno emergente en pacientes ancianos con patologías del tracto urinario. Se describen dos casos de bacteriemias por A. schaalii. Caso 1: Paciente de 79 años, con antecedente de hiperplasia benigna prostética. Ingresó a la guardia por síndrome febril, dolor abdominal y disuria. Caso 2: Paciente de 95 anos con adenomectomía prostética, uretrostomía por estrechez uretral e hiperplasia benigna prostética. Ingresó por síndrome febril, tos productiva, infiltrados bilaterales con imagen paracardíaca derecha y derrame pleural. En ambos pacientes se aisló A. schaalii en hemocultivos, identificado por espectrometría de masas MALDI-TOF MS. Solo en el caso 1 se confirmó que el foco de la bacteriemia fue urinario. Es importante sospechar la presencia de este patógeno emergente en infecciones urinarias con sedimento patológico, sin desarrollo en medios de cultivo tradicionales, para garantizar un tratamiento empírico adecuado, ya que la mayoría de los aislamientos presentan resistencia a ciprofloxacina y trimetoprima-sulfametoxazol.

Abstract Actinotignum schaalii is an emerging pathogen in elderly patients with urinary tract pathologies. Two cases of A. schaalii bacteremia are described. Case 1: 79-year-old patient with a history of benign prostatic hyperplasia. He was admitted to the ward for febrile syn-drome, abdominal pain, and dysuria. Case 2: 95-year-old patient with prostatic adenomectomy, urethrostomy due to urethral stricture, and benign prostatic hyperplasia. He was admitted due to febrile syndrome, productive cough, bilateral infiltrates with right paracardiac image, and pleural effusion. In both patients, A. schaalii was isolated in blood cultures, identified by MALDITOF-MS mass spectrometry. Only in case 1 was it confirmed that the focus of bac-teremia was urinary. It is important to suspect this emerging pathogen in urinary infections with pathological sediment without developing in traditional culture media to ensure ade-quate empirical treatment. Since most of the isolates show resistance to ciprofloxacin and trimethoprim-sulfamethoxazole.

Propionimicrobium lymphophilum and Actinotignum schaalii bacteraemia: a case report.

Propionimicrobium lymphophilum is an anaerobic Gram-positive bacillus that exists in human skin and urinary tract. The pathogenicity is, however, not well known. Only two cases of urinary tract infection have been described recently. In the case presented here, the bacterium was isolated, concomitant with Actinotignum schaalii, from blood culture of a patient with fever and difficulty of urination. The bacteria were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S rRNA sequencing. The case was successfully treated with ampicillin/sulbactam.