Journal of Clinical Microbiology最新文献

Biofilms are structured communities of microorganisms encased in a self-produced polymeric matrix that typically adhere to surfaces. Recent research, however, has revealed that non-attached aggregates share many common traits with the surface-dependent biofilms. This mode of bacterial growth provides enhanced protection against antibiotics and resistance to host immune defenses. Biofilms require higher antibiotic concentrations than those needed to inhibit planktonic bacteria, necessitating prolonged high-dose and combination therapies to achieve effective eradication. This increased resistance is attributed to multiple factors, including the protective extracellular matrix, reduced metabolic activity of bacteria within the biofilm, and also the ability of bacterial genomes to rapidly adjust in response to environmental changes. Diagnostic modalities such as sonication, tissue culture, and polymerase chain reaction-based assays currently dominate clinical diagnostics of biofilm infections due to their practicality, cost-effectiveness, and proven reliability. Recent research has led to innovative treatment strategies that target biofilm structure, enhance drug delivery, and modulate host-pathogen interactions. This review summarizes our current knowledge of biofilm formation, explores the current techniques for detecting microbial biofilms, and discusses future perspectives for advancing diagnostic and therapeutic strategies.

Leptospirosis, caused by Leptospira spp. infection, is a globally significant zoonotic disease that affects a wide range of animals. Although renal colonization is well-documented, genital infection by leptospires remained less explored for decades, despite its impact on reproduction. Evidence suggests that genital infection occurs as a primary condition rather than secondary to renal colonization, particularly in cattle suffering from bovine genital leptospirosis (BGL), linked to chronic infections by strains of the Sejroe serogroup. In horses, a similar condition is suggested to be associated with strains of serogroup Australis. Molecular studies confirmed the presence of Leptospira DNA in uterine, follicular, and vaginal samples, strengthening the hypothesis of an independent genital physiopathology. Despite significant advances in molecular diagnostics, the detection of genital carriers remains challenging, requiring refined methodologies beyond standard serology. This review critically examines the historical detection of Leptospira spp. in genital samples of cattle, small ruminants, swine, and equines, emphasizing its relevance to reproductive health. Moreover, we highlight the limitations of current diagnostic approaches, advocating for increased use of genital samples in leptospirosis research of large animals and shedding light on future directions regarding genital leptospirosis in livestock research. Enhanced understanding and diagnosis of genital leptospirosis will contribute to better livestock reproductive management and disease prevention.

Bovine tuberculosis, a zoonotic disease caused primarily by Mycobacterium bovis, poses a significant threat to cattle health and farming livelihoods within the United Kingdom (UK). Disease control in cattle is complicated by the persistence of M. bovis in European badgers, the UK's principal wildlife reservoir. Accurate diagnostic tools for both species are essential for effective surveillance and disease control. Many existing badger serodiagnostic tests, which include MPB70, MPB83, and ESAT6-CFP10 antigens, have relatively modest sensitivities (~50%-60%), limiting their utility in surveillance. To address this issue, we used an unbiased and comprehensive antigen discovery approach to identify new diagnostic targets. This strategy identified Rv3616c as a novel antigen with promising diagnostic test potential for M. bovis infection in badgers. Overlapping peptides spanning the full Rv3616c amino acid sequence were screened to identify the most diagnostically informative epitopes. A pool of four Rv3616c peptides, used in an indirect enzyme-linked immunosorbent assay (ELISA), had a sensitivity of 85.71% (95% CI: 77.19-91.96), a specificity of 94.80% (95% CI: 90.35-97.59), and a diagnostic accuracy of 91.51% (95% CI: 87.54-94.54). The existing validated Badger M. bovis Ab Test, when used alone, had a sensitivity of 73.47% (95% CI: 63.59-81.88); however, parallel interpretation with the Rv3616c ELISA could increase overall sensitivity to 91.84% (95% CI: 84.55-96.41), with minimal loss of specificity. These findings support the use of Rv3616c-derived peptides in serodiagnostic tests to improve the detection of M. bovis infection in badgers and enhance tuberculosis surveillance in this wildlife reservoir.IMPORTANCEAccurate diagnosis of Mycobacterium bovis infection in wildlife reservoirs is essential for controlling bovine tuberculosis (bTB), a zoonotic disease that threatens human health, animal welfare, and farming livelihoods. In the United Kingdom, European badgers are the principal wildlife reservoir, complicating efforts to eradicate bTB in cattle. Existing serodiagnostic tests for badgers have moderate sensitivity, limiting effectiveness in surveillance. To address this, this study used an unbiased, comprehensive antigen discovery approach and identified several new diagnostic targets, including the Rv3616c protein. A test based on specific Rv3616c-derived peptides had a high diagnostic accuracy (91.51%) and, when used in parallel with a validated test, improved test sensitivity while maintaining specificity. These synthetic peptides are scalable, cost-effective, and adaptable to different diagnostic platforms. The findings reveal an antigen with diagnostic potential that could inform the development of new tests for bTB surveillance in wildlife, supporting One Health principles and global tuberculosis elimination strategies.

There is increasing concern regarding the importance of Stenotrophomonas maltophilia as a nosocomial infection, given its inherent antibiotic resistance, particularly for patients who have risk factors such as being mechanically ventilated. The prevalence of colonization receiving mechanical ventilation in chronic care facilities has not been studied. The Multi-Drug-Resistant Organism (MDRO) Prevention Collaborative performed a point prevalence of patients receiving mechanical ventilation in all 18 chronic care facilities in Maryland between 7 March 2023 and 8 June 2023. Patients had at least one sputum, skin, or perianal surveillance culture collected (579 samples). Samples were tested using three microbiological methods: (i) growth on Acinetobacter CHROMagar, (ii) growth on MacConkey agar with an imipenem disk, and (iii) growth in brain-heart infusion broth with an imipenem disk, followed by growth on MacConkey agar. 21.4% (124/579) of the samples collected grew S. maltophilia. Among 200 patients, 58.5% had at least one positive site (117/200). S. maltophilia was isolated from 58.2% (113/194) of sputum, 4.1% (8/193) of skin, and 1.6% (3/185) of perianal samples. Two patients had multiple samples that grew S. maltophilia for a total of 119 positive samples from 117 patients. Mechanically ventilated patients in chronic care facilities may be at risk of S. maltophilia colonization and potential infection.IMPORTANCEThere is increasing concern regarding the importance of Stenotrophomonas maltophilia as a nosocomial infection, given its inherent antibiotic resistance. S. maltophilia is widely present in the environment, and while not always virulent, it has been documented to have high morbidity and mortality among certain at-risk patient populations. We analyzed mechanically ventilated patients in chronic care facilities in the state of Maryland to quantify the burden of S. maltophilia in this population. More than half of patients receiving mechanical ventilation in chronic care facilities were colonized with S. maltophilia, which was most frequently isolated from sputum samples.

Leptospirosis is a life-threatening zoonotic disease with a major public and animal health impact. Annually, approximately 1.03 million people are affected by leptospirosis, but our understanding of its impact on animals is limited. The epidemiology, pathogenesis, clinical presentation, diagnostic methods, and control measures for this disease differ significantly between humans and animals. This difference is due in part to the wide range of animal species that can be infected, the different infecting serovars present across species and geographic regions, and the existence of chronic asymptomatic reservoirs. Additionally, diagnosing leptospirosis in animals is complicated by the limited availability of sensitive, specific, and affordable diagnostic tools that can be employed at the point of care. There is often a trade-off between the sensitivity/specificity and accessibility of these diagnostics, and no single diagnostic test is entirely reliable. Many newer diagnostic methods lack validation for use in various animal species and clinical samples. In this minireview, we discuss the methods used for detecting Leptospira-infected animals and challenges associated with these techniques.

Pulmonary disease caused by Mycobacterium avium complex (MAC-PD) is a chronic, recurrent disease, and its high recurrence rate after treatment makes clinical management difficult. Distinguishing whether recurrence is due to persistence of existing strains or reinfection with new strains is essential for establishing treatment strategies, preventing overuse of antimicrobials, and establishing infection control measures. According to reports, 54%-74% of MAC-PD recurrence is due to reinfection, which may be mainly related to environmental reservoirs such as household water supply. In this review, we present various clinical scenarios in which MAC-PD recurrence may occur and examine genotyping techniques as a strategy to distinguish and respond to them. From traditional methods such as IS1245-based restriction fragment length polymorphism, pulsed-field gel electrophoresis, and hsp65 and rpoB gene sequencing to high-resolution analysis techniques such as multilocus sequence testing and whole-genome sequencing, the latest molecular typing methods are comprehensively summarized. Integrating these genotype data into clinical settings, standardizing single-nucleotide polymorphism-based interpretation thresholds, and promoting the establishment of a global MAC strain database will make a substantial contribution to more accurately distinguishing the recurrence mechanisms of MAC-PD and establishing personalized treatment strategies.IMPORTANCEThe global burden of nontuberculous mycobacterial pulmonary disease (PD) is increasing, with Mycobacterium avium (MAC)-PD being the most prevalent and clinically challenging form. Its low treatment success rates, high frequency of recurrence, and persistent environmental exposure complicate both diagnosis and management. A critical clinical issue is determining whether recurrence represents true relapse, due to persistence of the original strain, or reinfection with a new strain, as this guides treatment and prevents overtreatment. Genotypic strategies capable of resolving strain-level differences can improve diagnostic accuracy, prevent misclassification, and ultimately support more informed treatment decisions. Therefore, integrating genotyping data into clinical workflows, standardizing single-nucleotide polymorphism thresholds, and establishing a global MAC strain database will not only support personalized treatment but also enhance the broader public health response to this disease.