- Volume 71, Issue 9, 2022
Volume 71, Issue 9, 2022
- Editorials
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- Reviews
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A recurrent prosthetic joint infection caused by Erysipelothrix rhusiopathiae: case report and literature review
Prosthetic knee joint infection caused by Erysipelothrix rhusiopathiae is uncommon and only one case of recurrent infection has previously been described. Here, we describe the case of a 77-year-old male patient who was admitted to the teaching hospital of Rennes (France) with bilateral and nocturnal gonalgia evolving for 1 month. He had bilateral knee prosthesis 10 years ago, and a history of large B-cell lymphoma in remission. A diagnosis of infective endocarditis, with prosthetic knee infection, was made, with positive cultures of synovial fluids and blood; colonies of E. rhusiopathiae were identified by MALDI-TOF MS. Initial treatment involved debridement, implant retention surgery and intravenous amoxicillin (12 g day–1) for 6 weeks with gentamicin 3 mg kg–1 day–1 added for the first 4 days. One year later, a second episode of E. rhusiopathiae infection occurred, suggesting a recurrence or reinfection due to the same bacterial species. The patient was finally cured after a two-stage exchange with a cemented articulated spacer and a 3 month course of amoxicillin (12 g day–1, iv). Different characteristics of E. rhusiopathiae infection were discussed, with a review of all cases of prosthetic joint infections caused by Erysipelothrix species. This case highlights the need for a long-term survey of patients, and a good knowledge of their environment to avoid any risk of reinfection.
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- JMM Profiles
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JMM Profile: Brachyspira species: the causative agent of Avian Intestinal Spirochaetosis
More LessThe genus Brachyspira includes nine officially recognised species, several of which are pathogenic to mammals and birds. B. pilosicoli, B. intermedia, and B. alvinipulli are the causative agents of avian intestinal spirochaetosis (AIS), a gastrointestinal disease in poultry caused by the colonisation of the caeca and/ or colo-rectum by Brachyspira . AIS primarily affects layer hens and broiler breeders over the age of 15 weeks. The severity of symptoms can vary but typically presents as reduced growth rates, delayed onset of lay, reduced egg production, faecally stained eggs, and diarrhoea. This disease is estimated to cost the UK laying industry £18 million per annum. Brachyspira colonisation in humans is common in populations from developing countries and HIV-positive patients; however, it is rarely investigated as a human pathogen.
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- Antimicrobial Resistance
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Antimicrobial resistance and molecular characterization of gene cassettes from class 1 integrons in Salmonella strains
Jie Ma, Na An, Wanxiang Li, Mi Liu and Shirong LiIntroduction. The emergence of antibiotic-resistant Salmonella isolates is a global concern and has been attributed to the indiscriminate use of antibiotics in humans and animals. Integrons are mobile gene elements closely related to bacterial drug resistance. Among them, class 1 integrons containing various resistance gene cassettes could play an important role in disseminating and maintaining antibiotic resistance in Salmonella isolates.
Hypothesis. Salmonella class 1 integrons have a relationship with Salmonella drug resistance.
Aim. This study aims to investigate the distribution of class 1 integrons and their variable regional molecular characteristics, as well as the diversity of the promoters and drug sensitivity among Salmonella strains.
Methodology. A total of 111 Salmonella strains, collected between 2018 and 2020, underwent fully automated bacterial identification using the VITEK 2 Compact system and an antibiotic sensitivity test. PCR was employed to screen class 1 integrase genes (IntI1) and integron variable regions, while promoter type and variable region gene cassette characteristics were determined using sequencing analysis.
Results. A total of 24 IntI1-positive strains were detected in 111 Salmonella strains. Moreover, IntI1-positive strains exhibited statistically significant resistance to ceftazidime, ciprofloxacin, levofloxacin, ceftriaxone, trimethoprim/sulfamethoxazole and azithromycin compared to integron-negative strains (P<0.05). The multidrug resistance rate of IntI1-positive strains was significantly higher than that of negative strains. Variable regions were observed in 6 of the 24 IntI1-positive strains. Four gene cassettes were detected, namely dfrA17-aadA5, dfrA12-aadA2, aadA22 and aar-3-dfrA27. Finally, 3 types of class 1 integron variable region promoters were identified in 24 strains, including PcW, PcH1 and PcWTGN-10; they are all relatively weak promoters.
Conclusion. The integron and the drug resistance genes carried by integron have a certain relationship with drug resistance.
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- Clinical Microbiology
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Antimicrobial activity: potential of Spondias purpurea (Anacardiaceae) against bacterial and fungal species
More LessIntroduction. Plants have been used as medicines for centuries to treat human diseases. Studies with plants are extremely important for the development of future drugs that can benefit the human population.
Hypothesis/Gap Statement. With the emergence of pathogens resistant to antimicrobial agents, there is an urgent need to direct research towards the discovery of new antimicrobials.
Aim. In this study, Spondias purpurea L. (Anacardiaceae) was evaluated for its antimicrobial activity, antioxidant activity and cytotoxicity.
Methodology. Antimicrobial activity was evaluated by the MIC using the 96-well plate microdilution technique of ethanolic, hexanic and dicloromethanic extracts of dried S. purpurea leaves against bacteria, yeast and filamentous fungi. The antioxidant activity of extracts was evaluated by the 2,2-diphenyl-1-picrylhydrazine (DPPH) method. To evaluate the safety of extracts, a cytotoxicity study against HaCat, J774 and HepG2 cells was performed.
Results. The extracts had no activity against the bacteria at the maximum concentration of 5.0 mg ml−1, but showed fungistatic action against Candida species and dermatophytes. The ethanolic extract showed 88 % antioxidant activity and showed no significant cytotoxicity against the previously mentioned cells.
Conclusion. This study showed that the 100 % ethanolic (EtOH) extract was favourable for antifungal and antioxidant activities and did not present significant cytotoxicity against the three studied cell lines, indicating that S. purpurea leaves are promising for the development of new antimicrobials.
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- Disease, Diagnosis and Diagnostics
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Peritonsillar abscess: an 8-year retrospective, culture based evaluation of 208 cases
Introduction. Peritonsillar abscess (PTA) is a common infection which requires surgical intervention and suitable antibiotic therapy.
Hypotheses/Gap Statement. Beside Streptococcus pyogenes and Fusobacterium necrophorum several other mostly anaerobic bacteria can be cultured from the properly taken pus samples of PTA, the clinical significance of which is still not fully understood.
Aim. This study focused on the culture-based microbiological evaluation of PTA cases, compared to surgical intervention and empirical antibiotic management.
Methodology. A retrospective analysis of PTA cases was performed between 2012 and 2019. Data about the aerobic and anaerobic culture results of the samples taken during different surgical interventions were summarized and the coverage of the empirically selected antibiotics was evaluated. The patient’s history, the development of complications and the recurrence rate were also evaluated.
Results. The microbiological culture results were available for 208 of 320 patients with clinically diagnosed PTA. Incision and drainage (I and D) and immediate tonsillectomy were the leading surgical interventions. Ninety-five Fusobacterium species (including 44 Fusobacterium necrophorum ), 52 Actinomyces species and 47 Streptococcus pyogenes were obtained from PTA samples alone or together with polymicrobial flora. S. pyogenes (33.7 %, n=28) and F. necrophorum (22.9 %, n=19) were the dominating pathogens in the 83 monobacterial PTA samples. In >60 % of the patients polymicrobial infection was demonstrated, involving a great variety of anaerobic bacteria. In 22 out of 42 cases where intravenous cefuroxime was empirically started, the therapy should be changed to properly cover the culture-proven anaerobic flora. There were no serious complications, abscess recurrence was detected in two cases (0.96 %).
Conclusion. PTAs are often polymicrobial infections including a great variety of anaerobes. Targeted antibiotic therapy, in conjunction with adequate surgical drainage eliminating the anaerobic milieu, can accelerate the healing process and radically reduce the complication and recurrence rate.
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- Medical Mycology
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Microbiological and molecular screening of Candida spp. isolated from genital tract of asymptomatic pregnant women
Introduction. Candida spp. may cause opportunistic infections called vulvovaginal candidiasis (VVC), which is estimated to be the second most common cause of vaginitis worldwide.
Gap Statement. Under various circumstances, VVC could compromise pregnancy outcomes. Emerging data suggests that VVC during pregnancy may be associated with increased risk of complications and congenital cutaneous candidiasis.
Aim. To assess the prevalence of Candida spp. in asymptomatic pregnant women and determine the susceptibility of the isolates to antifungal drugs.
Methodology. In a prospective cohort, 65 high vaginal swab samples of consented pregnant women. Candida isolates were identified using both microbiological and molecular tools and drug susceptibilities were profiled.
Results. The prevalence of VVC among our study participants was 37 %, 24 of the 65 asymptomatic pregnant women show Candida spp. colonization. C. albicans was the most common species 61 %, followed by C. glabrata 39 %. In addition, a significant fraction of the isolated colonies showed resistance to Fluconazole, with a ratio of 63 % for C. albicans isolates and 16 % for Candida glabrata isolates. Moreover, relative quantification of genes related to resistance to fluconazole, CDR1, ERG11 as well as HWP1, showed a significant change compared to controls.
Conclusion. Monitoring of vaginal Candida colonization before the third trimester of pregnancy, that could reduce congenital Candida colonization and risk of pregnancy complications.
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- Microbiome and Microbial Ecology in Health
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Integrated analysis of intestinal microbiota and host gene expression in colorectal cancer patients
Introduction. Colorectal cancer (CRC) is one of the most common cancers and poses heavy burden on global health. The relationship between mucosal microbiome composition and colorectal gene expression are rarely studied. In this study, we integrated transcriptome data with microbiome data to investigate the relationship between them in colorectal cancer patients.
Gap statement. Previous studies have identified the contribution of gut microbiota and DEGs to the pathogenesis of CRC, but the relationship between mucosal microbiome composition and colorectal gene expression are rarely studied.
Aim. In this study, we integrated transcriptome data with microbiome data to investigate the relationship between mucosal microbiome composition and colorectal gene expression.
Methodology. First, three independent CRC gene expression profiles (GSE184093, GSE156355 and GSE146587) from Gene Expression Omnibus (GEO) were used to identify differentially expressed genes (DEGs). Second, another dataset (GSE163366) was used to analyse gut mucosal microbiome differential abundance. GO (Gene Ontology) function and KEGG (Kyoto Encyclopaedia of Genes and Genomes) pathway enrichment analyses of the DEGs were performed. Protein-protein interactions (PPIs) of the DEGs were constructed. The Spearman correlation analysis was computed between host DEGs and gut microbiome abundance data.
Results. A total of 1036 upregulated DEGs and 1194 downregulated DEGs between noncancerous tissues and cancerous tissues were identified based on the analysis. One significant module with a score 37.65 was selected out via MCODE including 41 upregulated DEGs, which are were mostly enriched in two pathways, including microtubule binding and tubulin binding. In particular, significant negative correlations are prevalent between Fusobacterium and the 41 DEGs with the correlation ranging between −0.54 and −0.35, and there commonly exist significant positive correlations between Blautia and the 41 DEGs with the correlation ranging between 0.42 and 0.54, indicating that Fusobacterium and Blautia are two of the most important microbes interacting with the gene regulation.
Conclusion. Our results demonstrate significant correlation between some gut microbes and DEGs, providing a comprehensive bioinformatics analysis of them for future investigation into the molecular mechanisms and biomarkers.
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Volumes and issues
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Volume 73 (2024)
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