Direct detection of Corynebacterium striatum, Corynebacterium propinquum, and Corynebacterium simulans in sputum samples by high-resolution melt curve analysis

Rising prevalence and drug resistance of Corynebacterium striatum in lower respiratory tract infections

Corynebacterium striatum (C. striatum) is a Gram-positive bacterium commonly colonizing the skin and mucosa in healthy individuals and hospitalized patients. Traditionally regarded as a contaminant, C. striatum is now increasingly recognized as a potential cause of clinical infections, especially after the coronavirus disease pandemic. It has emerged as a pathogen implicated in severe infections, including pneumonia, bacteremia, meningitis, artificial joint infections, abdominal infections, and endocarditis. C. striatum has been reported in lower respiratory tract infections, mostly as a conditioned pathogen in immunocompromised individuals, particularly in those with chronic structural lung diseases, such as chronic obstructive pulmonary disease, leading to severe pneumonia or exacerbation of the existing disease and high mortality. Additionally, C striatum has been implicated in the community-acquired pneumonia among immunocompetent individuals and nosocomial lung infections, with evidence of person-to-person transmission through caregivers. C. striatum may exhibit multidrug resistance. Vancomycin, alone or in combination, is currently considered the most effective treatment for C. striatum. This review highlights the epidemiological characteristics, drug resistance mechanisms, diagnostics approaches, and treatment options for C. striatum lower respiratory tract infections to enhance clinician awareness and improve patient management strategies.

Relapsing peritoneal dialysis-associated peritonitis caused by Corynebacterium striatum: a case report

Peritoneal dialysis (PD)-associated peritonitis is a serious complication of PD, and its prevention and treatment are important for reducing patient morbidity and mortality. Reports of PD-associated peritonitis caused by Corynebacterium spp. are limited, and PD-associated peritonitis caused by Corynebacterium striatum (C. striatum) is rare. Only two case reports are available, wherein improvement was only achieved after intraperitoneal administration of antibiotics. Here, we report a case of relapsing PD-associated peritonitis caused by C. striatum that did not improve with antibiotic therapy. In this case, the patient started PD due to end-stage renal failure with immunoglobulin A nephropathy. In addition, he had been diagnosed with bronchiectasis and was prescribed clarithromycin. Four days after PD induction, the patient developed culture-negative PD-associated peritonitis. Ceftazidime and cefazolin were subsequently administered intraperitoneally for a total of 14 days, resulting in improvement in his condition. However, 3 and 5 months after PD induction, he developed PD-associated peritonitis again, and C. striatum was detected in each culture. He was treated with intraperitoneal vancomycin for a total of 14 days and improved; however, he developed PD-associated culture-negative peritonitis again 7 months later. We diagnosed relapsing PD-associated peritonitis caused by C. striatum. PD catheter removal and reinsertion were performed, and he has not relapsed since. In conclusion, PD-associated peritonitis caused by C. striatum may have a poor prognosis; therefore, PD catheter removal is recommended, especially in patients with a history of repeated PD-related peritonitis due to C. striatum.

The first case of urosepsis caused by Corynebacterium aurimucosum in an immunocompetent patient

Non-diphtheroid Corynebacterium sepsis is rare and has affected only immunocompromised or particularly predisposed patients so far. We present the first case of urosepsis caused by Corynebacterium aurimucosum in a 67-year-old woman, without any known immunodeficiencies and in absence of any immunosuppressive therapy, admitted to the hospital for fever and acute dyspnea. This work suggests a new approach in evaluating the isolation of Corynebacteria, especially if isolated from blood. In particular, it highlights the potential infectious role of C. aurimucosum (often considered a contaminant and only rarely identified as an etiological agent of infections) and its clinical consequences, detailing also interesting aspects about its microbiological diagnosis and relative therapy and clarifying contrasting data of literature.

Public knowledge, attitudes, and practices (KAP) regarding antibiotics use and antimicrobial resistance (AMR) in Bangladesh

Background

Antibiotic resistance is a global public health concern that requires an understanding of public knowledge, attitudes, and practices (KAP) towards antibiotics. This study aimed to assess the KAP regarding antibiotic use and AMR among the general population in Bangladesh.

Methods

A cross-sectional survey was conducted among 656 respondents in Bangladesh. Data on socio-demographic characteristics, knowledge, attitudes, and practices regarding antibiotics use and AMR were collected through a structured questionnaire. Descriptive statistics and ordered logit regression analysis were performed to analyze the data.

Results

The study involved participants, with 52.44 % aged 18 to 30, 77.29 % males, and 92.53 % having primary education or higher. Urban residents were 80 %, and students formed the largest occupational group (29.57 %), followed by businessmen (25 %), service holders (24.7 %), housewives (10.52 %), and day laborers (8.84 %). The majority of respondents demonstrated average knowledge (52.29 %), moderate attitudes (67.84 %), and good practices (50.61 %) regarding antibiotic use and AMR. Socioeconomic factors such as education, media exposure, and urban residence significantly (1 % level of significance) influenced KAP. The findings revealed knowledge gaps and misconceptions among the respondents, including incorrect beliefs about antibiotic resistance (42%), and inadequate awareness of the importance of completing full antibiotic courses (54.88 %).

Conclusion

This study sheds light on the existing KAP related to antibiotic use and AMR within the general population of Bangladesh. The findings reveal varying levels of knowledge, attitudes, and practices among the participants. The results underscore the importance of addressing knowledge gaps, and misconceptions for awareness building through educational campaigns utilizing social media platforms and newspapers. These insights provide a foundation for informed strategies to ensure the continued efficacy of antibiotics.

Skincare potential of a sustainable postbiotic extract produced through sugarcane straw fermentation by Saccharomyces cerevisiae

Postbiotics are defined as a "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host." They can be produced by fermentation, using culture media with glucose (carbon source), and lactic acid bacteria of the genus Lactobacillus, and/or yeast, mainly Saccharomyces cerevisiae as fermentative microorganisms. Postbiotics comprise different metabolites, and have important biological properties (antioxidant, anti-inflammatory, etc.), thus their cosmetic application should be considered. During this work, the postbiotics production was carried out by fermentation with sugarcane straw, as a source of carbon and phenolic compounds, and as a sustainable process to obtain bioactive extracts. For the production of postbiotics, a saccharification process was carried out with cellulase at 55°C for 24 h. Fermentation was performed sequentially after saccharification at 30°C, for 72 h, using S. cerevisiae. The cells-free extract was characterized regarding its composition, antioxidant activity, and skincare potential. Its use was safe at concentrations below ~20 mg mL-1 (extract's dry weight in deionized water) for keratinocytes and ~ 7.5 mg mL-1 for fibroblasts. It showed antioxidant activity, with ABTS IC50 of 1.88 mg mL-1 , and inhibited elastase and tyrosinase activities by 83.4% and 42.4%, respectively, at the maximum concentration tested (20 mg mL-1 ). In addition, it promoted the production of cytokeratin 14, and demonstrated anti-inflammatory activity at a concentration of 10 mg mL-1 . In the skin microbiota of human volunteers, the extract inhibited Cutibacterium acnes and the Malassezia genus. Shortly, postbiotics were successfully produced using sugarcane straw, and showed bioactive properties that potentiate their use in cosmetic/skincare products.

Relationships between Secreted Aspartyl Proteinase 2 and General Control Nonderepressible 4 gene in the Candida albicans resistant to itraconazole under planktonic and biofilm conditions

This study aimed to explore the roles of SAP2 and GCN4 in itraconazole (ITR) resistance of C. albicans under different conditions, and their correlations. A total of 20 clinical strains of C. albicans, including 10 ITR resistant strains and 10 sensitive strains, were used. Then, SAP2 sequencing and GCN4 sequencing were performed, and the biofilm formation ability of different C. albicans strains was determined. Finally, real-time quantitative PCR was used to measure the expression of SAP2 and GCN4 in C. albicans under planktonic and biofilm conditions, as well as their correlation was also analyzed. No missense mutations and three synonymous mutation sites, including T276A, G543A, and A675C, were found in SAP2 sequencing. GCN4 sequencing showed one missense mutation site (A106T (T36S)) and six synonymous mutation sites (A147C, C426T, T513C, T576A, G624A and C732T). The biofilm formation ability of drug-resistant C. albicans strains was significantly higher than that of sensitive strains (P < 0.05). Additionally, SAP2 and GCN4 were up-regulated in the ITR-resistant strains, and were both significantly higher in C. albicans under biofilm condition. The mRNA expression levels of SAP2 and GCN4 had significantly positive correlation. The higher expression levels of SAP2 and GCN4 were observed in the ITR-resistant strains of C. albicans under planktonic and biofilm conditions, as well as there was a positive correlation between SAP2 and GCN4 mRNA expression.

Development of high-resolution melting (HRM) assay to differentiate the species of Shigella isolates from stool and food samples

Shigella species, a group of intracellular foodborne pathogens, are the main causes of bacillary dysentery and shigellosis in humans worldwide. It is essential to determine the species of Shigella in outbreaks and food safety surveillance systems. The available immunological and molecular methods for identifying Shigella species are relatively complicated, expensive and time-consuming. High resolution melting (HRM) assay is a rapid, cost-effective, and easy to perform PCR-based method that has recently been used for the differentiation of bacterial species. In this study, we designed and developed a PCR-HRM assay targeting rrsA gene to distinguish four species of 49 Shigella isolates from clinical and food samples and evaluated the sensitivity and specificity of the assay. The assay demonstrated a good analytical sensitivity with 0.01–0.1 ng of input DNA template and an analytical specificity of 100% to differentiate the Shigella species. The PCR-HRM assay also was able to identify the species of all 49 Shigella isolates from clinical and food samples correctly. Consequently, this rapid and user-friendly method demonstrated good sensitivity and specificity to differentiate species of the Shigella isolates from naturally contaminated samples and has the potential to be implemented in public health and food safety surveillance systems.