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

Tsukamurella conjunctivitidis peritonitis diagnosed by 16S rRNA gene sequencing in a patient undergoing peritoneal dialysis

Peritoneal dialysis (PD)-associated peritonitis remains a serious and life-threatening complication in patients undergoing PD. Majority of peritonitis cases are caused by bacteria, with coagulase-negative Staphylococcus being the most common cause. Tsukamurella species are obligate aerobic gram-positive bacilli found in various environments; however, peritonitis caused by Tsukamurella species in association with PD is rare, with few reports of infections caused by T. conjunctivitidis, including PD-associated peritonitis. We describe a rare case of peritonitis caused by T. conjunctivitidis in a patient undergoing PD. A 62-year-old man undergoing PD was referred to our hospital for fever and abdominal pain lasting for 4 days and was diagnosed with PD-associated peritonitis based on abdominal pain, cloudy effluent, elevated white blood cell count in the peritoneal fluid, and presence of gram-positive rods in the effluent culture. Yellow-grayish, dry, membrane-like colonies were observed on a blood agar plate. The isolated strain was identified as T. conjunctivitidis through 16S rRNA gene sequencing. Because the PD-associated peritonitis was refractory to antibiotics, the PD catheter was removed, and the patient was switched to hemodialysis on day 21 of admission. Clinicians should consider peritonitis caused by T. conjunctivitidis as a differential diagnosis in cases where diagnosis using routine examination is challenging. Notably, 16S rRNA gene sequencing is a useful diagnostic tool for identifying T. conjunctivitidis. Further analyses of similar cases are required to understand the characteristics of such infections and establish adequate diagnostic methods and treatment regimens.

Mucosal infection with Tsukamurella species following nasal septum procedure: a rare case report

Introduction and importance

Tsukamurella species are rare, aerobic, gram-positive bacteria known to cause infections, primarily in immunocompromised individuals. This case report presents a rare instance of a mucosal infection caused by Tsukamurella species following a nasal septum procedure in an immunocompetent patient.

Case presentation

A 51-year-old man with a history of multiple hereditary exostosis, allergic rhinitis, and recent nasal fracture repair presented with persistent fevers and low back pain. Postoperatively, he developed sinus pain and small oral lesions, initially treated with antibiotics for presumed sinusitis. Despite treatment, his fever persisted, leading to an emergency department visit. Laboratory tests indicated sepsis, but a CT scan of the sinuses showed no sinusitis. Despite broad-spectrum antibiotics, the patient's fever continued. On admission day 9, nasal endoscopy and culture identified Tsukamurella species. The patient was treated with augmentin, fluconazole, and levofloxacin, leading to the resolution of symptoms and discharge with ongoing treatment.

Clinical discussion

Tsukamurella species are uncommon pathogens that are often associated with bacteremia in immunocompromised individuals. This case highlights the diagnostic challenges and the importance of considering unusual pathogens in postprocedural infections, even in immunocompetent patients. Accurate identification and appropriate management are critical in improving outcomes for patients with Tsukamurella infections.

Conclusion

This case underscores the need for vigilance in diagnosing rare infections like Tsukamurella, even in immunocompetent individuals. The successful resolution with combination therapy highlights the importance of appropriate antibiotic selection in managing such infections.

Social wasp-associated Tsukamurella sp. strains showed promising biosynthetic and bioactive potential for discovery of novel compounds

In the face of escalating antibiotic resistance, the quest for novel antimicrobial compounds is critical. Actinobacteria is known for producing a substantial fraction of bioactive molecules from microorganisms, nonetheless there is the challenge of metabolic redundancy in bioprospecting. New sources of natural products are needed to overcome these current challenges. Our present work proposes an unexplored potential of Neotropical social wasp-associated microbes as reservoirs of novel bioactive compounds. Using social wasp-associated Tsukamurella sp. strains 8F and 8J, we aimed to determine their biosynthetic potential for producing novel antibiotics and evaluated phylogenetic and genomic traits related to environmental and ecological factors that might be associated with promising bioactivity and evolutionary specialization. These strains were isolated from the cuticle of social wasps and subjected to comprehensive genome sequencing. Our genome mining efforts, employing antiSMASH and ARTS, highlight the presence of BGCs with minimal similarity to known compounds, suggesting the novelty of the molecules they may produce. Previous, bioactivity assays of these strains against bacterial species which harbor known human pathogens, revealed inhibitory potential. Further, our study focuses into the phylogenetic and functional landscape of the Tsukamurella genus, employing a throughout phylogenetic analysis that situates strains 8F and 8J within a distinct evolutionary pathway, matching with the environmental and ecological context of the strains reported for this genus. Our findings emphasize the importance of bioprospecting in uncharted biological territories, such as insect-associated microbes as reservoirs of novel bioactive compounds. As such, we posit that Tsukamurella sp. strains 8F and 8J represent promising candidates for the development of new antimicrobials.

Peritoneal dialysis-associated peritonitis caused by Tsukamurella inchonensis: a case report and literature review

Background

Peritoneal dialysis (PD)-associated peritonitis is a serious complication that can lead to PD discontinuation and mortality. Tsukamurella species are uncommon opportunistic pathogens that can cause peritonitis, often necessitating catheter removal.

Case presentation

A 46-year-old woman with a 1.5-year history of PD presented with fever and lower abdominal pain, along with cloudy peritoneal effluent showing an elevated cell count. Empiric antibiotic therapy with ciprofloxacin, cefazolin, and ceftazidime was started for PD-associated peritonitis. The peritoneal effluent culture yielded a gram-positive rod with weak acid-fast staining. A rebound in the cell count necessitated a switch of antibiotics to meropenem and vancomycin. This led to improvement, and the treatment was switched to oral levofloxacin on day 30 and the patient was discharged on day 35. Subsequently, 16S rRNA gene sequencing confirmed the isolate as Tsukamurella inchonensis.

Conclusion

This case highlights the challenges in identifying and treating Tsukamurella peritonitis. Successful treatment without catheter removal in this case suggests that early detection and appropriate antibiotics may enable catheter salvage in this rare infection. However, further research is needed to establish optimal treatment strategies.

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.

Uncommon finding in a pulmonary graft versus host disease: A first report of Tsukamurella pneumonia in a pulmonary graft-versus-host disease

A 64-year-old woman presented to Our Department with 2 weeks history of fever and cough. Through a series of radiological and invasive diagnostic studies we finally reach an unexpected diagnosis of Tsukamurella pneumonia; Diagnosing an ILD is a dynamic process, and that is the reason why complex cases discussed in a multidisciplinary team may need to be reconsidered in light of evolution of the disease and the results of the performed exams with a flexible approach. Tsukamurella spp. is an obligate aerobic, Gram-positive, weakly acid-fast, non-motile bacillus that belongs to the order Actinomycetales. Pneumonia caused by Tsukamurella is exceedingly rare, and only few cases are reported in the literature. Our aim is to evidence the paramount importance of Multidisciplinary team discussion in deciding the most appropriate diagnostic is of and therapeutical strategy.

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.

Systematic investigation of the emerging pathogen of Tsukamurella species in a Chinese tertiary teaching hospital

Tsukamurella species have been clinically regarded as rare but emerging opportunistic pathogens causing various infections in humans. Tsukamurella pneumonia has often been misdiagnosed as pulmonary tuberculosis due to its clinical presentation resembling tuberculosis-like syndromes. Tsukamurella species have also been confused in the laboratory with other phylogenetic bacteria, such as Gordonia. This study aimed to investigate the clinical, microbiological, and molecular characteristics; species distribution; and antimicrobial susceptibility of Tsukamurella species. Immunodeficiency and chronic pulmonary disease appeared to be risk factors for Tsukamurella pneumonia, and the presence of bronchiectasis and pulmonary nodules on imaging was highly correlated with this infection. The study confirmed that groEL (heat shock protein 60) and secA (the secretion ATPase) genes are reliable for identifying Tsukamurella species. Additionally, the ssrA (stable small RNA) gene showed promise as a tool for discriminating between different Tsukamurella species with the shortest sequence length. In terms of antimicrobial susceptibility, quinolones, trimethoprim/sulfamethoxazole, amikacin, minocycline, linezolid, and tigecycline demonstrated potent in vitro activity against Tsukamurella isolates in our study. The study also proposed a resistance mechanism involving a substitution (S91R) within the quinolone-resistance-determining region of the gyrA gene, which confers resistance to levofloxacin and ciprofloxacin. Furthermore, we found that disk diffusion testing is not suitable for testing the susceptibilities of Tsukamurella isolates to ciprofloxacin, imipenem, and minocycline. In conclusion, our systematic investigation may contribute to a better understanding of this rare pathogen. Tsukamurella species are rare but emerging human pathogens that share remarkable similarities with other mycolic acid-containing genera of the order Actinomycetales, especially Mycobacterium tuberculosis. Consequently, misdiagnosis and therapeutic failures can occur in clinical settings. Despite the significance of accurate identification, antimicrobial susceptibility, and understanding the resistance mechanism of this important genus, our knowledge in these areas remains fragmentary and incomplete. In this study, we aimed to address these gaps by investigating promising identification methods, the antimicrobial susceptibility patterns, and a novel quinolone resistance mechanism in Tsukamurella species, utilizing a collection of clinical isolates. The findings of our study will contribute to improve diagnosis and successful management of infections caused by Tsukamurella species, as well as establishing well-defined performance and interpretive criteria for antimicrobial susceptibility testing.