Actinomycetoma by Actinomadura madurae. Clinical and therapeutic characteristics of 18 cases with two treatment modalities

A Rare Strain Actinomadura geliboluensis Was First Isolated from the Bronchoalveolar Lavage Fluid of a Patient with Pneumonia

Background

Actinomadura geliboluensis was first isolated in 2012 in Gelibolu, Canakkale, Turkey, and has not been reported to be isolated from humans until now. We have isolated it from the bronchoalveolar lavage fluid (BLF) of a patient with pneumonia and found its drug resistance. It is the first time that Actinomadura geliboluensis has been isolated from humans since its discovery and naming. This case may provide new ideas and methods for the clinical diagnosis and treatment of pulmonary actinomycosis.

Case Description

The patient was a 75-year-old male who was hospitalized in a township hospital and failed to improve after penicillin treatment. After admission to our hospital, the patient was treated with piperacillin/tazobactam according to clinical guidelines for 14 days. Actinomadura geliboluensis was isolated from the patient's BLF and was identified by 16S rRNA sequencing. This report shows the biological characteristics and in vitro drug susceptibility testing, as well as the genomics analysis based on next-generation sequencing (NGS). The results demonstrated that Actinomadura geliboluensis was easy to be mistakenly identified as Actinomyces dental caries by using the Merieux ANC identification card. Based on the MIC test, Actinomadura geliboluensis was susceptible to tetracyclines, quinolones and sulfonamides, but resistant to carbapenems, penicillins and cephalosporins. The K-B test results showed Actinomadura geliboluensis was highly sensitive to piperacillin/tazobactam. Genomic analysis based on NGS showed that the Actinomadura geliboluensis belongs to Planobispora rosea EF-Tu mutants conferring resistance to inhibitor GE2270A, AAC(3)-VIIa, vanRO, chrB, and mexY.

Conclusion

Actinomycetes is generally sensitive to Penicillin but Actinomadura geliboluensis is not. In vitro drug susceptibility test is needed to support individualized drug use to avoid delay in the disease.

Fate of resistome components and characteristics of microbial communities in constructed wetlands and their receiving river

Currently, most researches focus on that constructed wetlands (CWs) achieve desirable removal of antibiotics, antibiotic resistance genes (ARGs) and human pathogens. However, few studies have assessed the fate of resistome components, especially the behavior and cooccurrence of ARGs, mobile genetic elements (MGEs) and virulence factors (VFs). Therefore, characteristics of microbial communities (MCs) in CWs and their receiving rivers also deserve attention. These factors are critical to water ecological security. This study used two CWs to explore the fate of resistome components and characteristics of MCs in the CWs and their receiving river. Eleven samples were collected from the two CWs and their receiving river. High-throughput profiles of ARGs and microbial taxa in the samples were characterized. 31 ARG types consisting of 400 subtypes with total relative abundance 42.63-84.94× /Gb of sequence were detected in CWs, and 62.07-88.08× /Gb of sequence in river, evidencing that ARG pollution covered CWs and the river, and implying huge potential risks from ARGs. MGEs and VFs were detected, and tnpA, IS91 and intI1 were the three dominant MGEs, while Flagella. Type IV pili and peritrichous flagella were main VFs. Both CWs can remove ARGs, MGEs and VFs efficiently. However, some ARGs were difficult to remove, such as sul1 and sul2, and certain ARGs remained in the effluent of the CWs. The co-occurrence of ARGs, MGEs, and VFs implies the risk of antibiotic resistance and dissemination of ARGs. Eighty-five types of human pathogen were detected in the river samples, particularly Pseudomonas aeruginosa, Bordetella bronchiseptica, Aeromonas hydrophila and Helicobacter pylori. Correlation analysis indicated that MCs had significant effects on the profiles of ARGs in the water environment. This study reveals potential risks of the reuse of reclaimed water, and illustrates the removal ability of ARGs and related elements by CWs. This study will be helpful for monitoring and managing resistomes in water environments.

The developed molecular biological identification tools for mycetoma causative agents: An update

Mycetoma is a chronic granulomatous inflammatory disease that is caused either by bacteria or fungi. Bacterial mycetoma (actinomycetoma) can be caused by various causative agents of the genera Nocardia, Streptomyces and Actinomadura. On the other hand, fungal mycetoma (eumycetoma) is most commonly caused by causative agents belonging to the genera Madurella, Scedosporium and Falciformispora. Early and accurate diagnosis of the causative organisms can guide proper patient management and treatment. To allow rapid and accurate species identification, different molecular techniques were developed over the past decades. These techniques can be protein based (MALDI-TOF MS) as well as DNA based (Sequencing, PCR and isothermal amplification methods). In this review, we provide an overview of the different molecular techniques currently in use and identify knowledge gaps, which need to be addressed before we can implement molecular diagnostics for mycetoma in different clinical settings.

Actinomadura soli sp. nov., isolated from the top soil layer on basaltic material in Turkey

An actinobacterium, designated 14C53^T, was isolated from a soil sample on basaltic material from Samsun, Turkey. The growth ranges for NaCl concentration and pH of strain 14C53^T were quite limited and the growth temperature range of the strain was 20-37 °C, with an optimum at 28 °C. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain 14C53^T was most closely related to Actinomadura geliboluensis A8036^T (98.5 % similarity value), but in the phylogenetic tree, it formed a clade with Actinomadura alkaliterrae D310A^T. The genome tree revealed a close relationship between the strain and Actinomadura pelletieri DSM 43383^T. However, the digital DNA-DNA hybridization and average nucleotide identity values between strain 14C53^T with Actinomadura geliboluensis A8036^T and Actinomadura pelletieri DSM 43383^T were 28.6-30.2 % and 84.3-85.5 %, respectively, and comparative analyses based on the genome sequences demonstrated that it represents a novel species of the genus Actinomadura. The genome size of strain 14C53^T was approximately 9.0 Mb and the genomic DNA G+C content of the strain was 71.3 mol%. The major cellular fatty acids of strain 14C53^T were C_16 : 0 and iso-C_16 : 0. Strain 14C53^T contained meso-diaminopimelic acid as the diamino acid in the cell-wall peptidoglycan. The predominant menaquinones were MK-9(H₈) and MK-9(H₆). Based on evidence collected from the phenotypic, genotypic and phylogenetic analyses, a novel species Actinomadura soli sp. nov. is proposed, with 14C53^T (=DSM 104447^T=KCTC 39878^T) as the type strain.