Catheter-related bloodstream infection due to Tsukamurella pulmonis identified by MALDI-TOF spectrometry, 16S rRNA gene sequencing, and secA1 gene sequencing in an immunocompromised child: a case report and literature review

A Case Report of a Rare Pulmonary Opportunistic Infection in an Infant Caused by Tsukamurella tyrosinosolvens

This case report describes the case of a female infant hospitalized for severe pneumonia. During the treatment process, various antibiotics are used to treat and prevent further infection. The child had a weak physical condition, combined with neuroblastoma, paraneoplastic syndrome, and low immune function, leading to Tsukamurella tyrosinosolvens infection. The treatment was eventually abandoned owing to poor prognosis. This study aims to through the medium, dyeing, electron microscope observation, 16s rRNA and high-throughput sequencing investigated the morphological characteristics, staining properties, electron microscope morphology, antibiotic resistance, and genomic characteristics of Tsukamurella tyrosinosolvens. The aim of the study is to provide data reference for clinical laboratory staff in bacteria identification research, and to provide relevant help for clinicians in diagnosis and treatment.

Tsukamurella Bacteremia in a Surgical Patient: Case Report and Review of the Literature

Background: Tsukamurella species were first isolated in 1941. Since then, 48 cases of Tsukamurella bacteremia have been reported, a majority of which were immunosuppressed patients with central venous catheters.A case is described and previous cases of Tsukamurella bacteremia are reviewed. Patients and Methods: A 70-year-old total parenteral nutrition (TPN)-dependent female with recurrent enterocutaneous fistula (ECF), developed leukocytosis one week after a challenging ECF takedown. After starting broad-spectrum antibiotic agents, undergoing percutaneous drainage of intra-abdominal abscess, and subsequent repositioning of the drain, her leukocytosis resolved. Blood and peripherally inserted central catheter (PICC) cultures grew Tsukamurella spp. The patient was discharged to home with 14 days of daily 2 g ceftriaxone, with resolution of bacteremia. Conclusions: Tsukamurella spp. are a rare opportunistic pathogen predominantly affecting immunocompromised patients, with central venous catheters present in most cases. However, there have been few reported cases in immunocompetent individuals with predisposing conditions such as end-stage renal disease and uncontrolled diabetes mellitus.

Catheter-related bloodstream infection caused by Tsukamurella tyrosinosolvens identified by secA1sequencing in an immunocompromised child: a case report

BACKGROUND

Tsukamurella spp. are obligate aerobic, gram-positive, non-motile, and slightly acid-fast bacilli belonging to the Actinomycetes family. They share many characteristics with Nocardia, Rhodococcus, Gordonia, and the rapidly growing Mycobacterium species. Therefore, standard testing may misidentify Tsukamurella spp. as another species. Accurate and rapid diagnosis is critical for proper infection management, but identification of this bacterium is difficult in the standard laboratory setting.

CASE PRESENTATION

A bloodstream infection caused by a gram-positive bacterium and related to a central venous catheter was identified in an immunocompromised 2-year-old girl. Tsukamurella tyrosinosolvens was identified by modified secA1 sequencing. Antibiotic treatment and removal of the central venous catheter resolved the infection. Inappropriate management of the catheter during an overnight stay outside of the hospital was considered as a possible source of infection.

CONCLUSIONS

SecA1 sequencing may be a useful diagnostic tool in the identification of T. tyrosinosolvens. Providing proper central venous catheter care instructions to patients, their families, and medical staff is important for infection prevention.

Obligate aerobic, gram-positive, weak acid-fast, nonmotile bacilli, Tsukamurella tyrosinosolvens: Minireview of a rare opportunistic pathogen

Tsukamurella species are obligate aerobic, gram-positive, weak acid-fast, nonmotile bacilli. They are found in various environments, such as soil, water, sludge, and petroleum reservoir wastewater, and belong to the order Actinomycetales. In 2016, there was a reclassification of species within the genus Tsukamurella, merging the species Tsukamurella tyrosinosolvens (T. tyrosinosolvens) and Tsukamurella carboxydivorans. Tsukamurella species are clinically considered to be a rare opportunistic pathogen, because most reported cases have been related to bacteremia and intravascular prosthetic devices and immunosuppression. To date, it has been isolated only from human specimens, and has always been associated with clinical disease; human infections are very rare. Reported infections have included pneumonia, brain abscesses, catheter-related bloodstream infections, ocular infections, bacteremia, and sepsis presenting with septic pulmonary emboli in patients who are immunocompromised. To date, there is no commercially available test for identification. On the other hand, sequence-based identification, including matrix-assisted laser desorption ionization time-of-flight mass spectrometry, is an alternative method for identifying clinical isolates that are either slow growers or difficult to identify through biochemical profiling. The golden standards for diagnosis and optimal management still remain to be determined. However, newer molecular biological techniques can provide accurate identification, and contribute to the appropriate selection of definitive therapy for infections caused by this organism. Combinations of several antimicrobial agents have been proposed for treatment, though the length of treatment for infections has yet to be determined, and should be individualized according to clinical response. Immunocompromised patients often experience severe cases due to infection, and life-threatening T. tyrosinosolvens events associated with dissemination and/or failure of source control have occurred. Favorable prognoses can be achieved through earlier identification of the cause of infection, as well as successful management, including appropriate antibiotic therapy together with source control. Further analyses of similar cases are required to establish the most adequate diagnostic methods and treatment regimens for infections.

A fatal case associated with Catabacter hongkongensis bacteremia in lung cancer patient: A case report

Catabacter hongkongensis is a bacterium first isolated in 2007 and has since been detected in the blood of about fifteen patients with disease such as gastrointestinal malignancy, intestinal obstruction, or acute intestinal infection. We describe herein the case of a patient newly diagnosed with metastatic lung cancer, who died from a fatal infection possibly related to Catabacter hongkongensis bacteremia. By reviewing all cases reported in the literature, our case report supports that this infection is associated with a very high mortality in cancer patients.

Catheter-related bloodstream infection caused by Tsukamurella ocularis: A case report

Tsukamurella spp. causes mainly bacteremia and central venous catheter-related bloodstream infections. To the best of our knowledge, there is no documented evidence that Tsukamurella ocularis causes catheter-related bloodstream infections like other species of Tsukamurella. We present a novel case of T. ocularis bacteremia in a 69-year-old woman with malignant cancer, wherein the patient was successfully treated with a peripherally inserted central venous catheter. We administered combination antimicrobial therapy to the patient, which was terminated only after confirming the absence of infection. We identified T. ocularis by sequencing three housekeeping genes that could not be identified using conventional mass spectrometry and 16S rRNA gene analysis.

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.