Access microbiology最新文献

Ten non-dermatophytic moulds isolated from both symptomatic and asymptomatic cattle skin, including Penicillum citrinum, Aspergillus welwitschiae, Aspergillus aculeatus, Curvularia kusanol, Cladosporium teniussmum, Pestalotiopsis microspora, Fusarium oxysporum, Fusarium linchenicola, Absidia sp. and Aspergillus fumigatus, were subjected to a pathogenicity test using albino mice. These isolates were also screened for five enzymes using a standard plate method. Results from pathogenicity tests showed that Absidia sp., Cladosporium tenuissimum and Aspergillus welwitschiae were able to elicit discoloration, lesion production and alopecia on the albino mice skin, respectively, providing evidence of clinical symptoms associated with cutaneous mycoses. The enzyme screening results revealed the highest zone of activity for keratinase (65 mm), amylase (86 mm), protease (60 mm), lipase (60 mm) and cellulase (86 mm) which were observed on Pestalotiopsis microspora, Aspergillus welwitschiae, Cladosporium tenuissimum, Aspergillus welwitschiae and Aspergillus welwitschiae respectively. Pathogenicity tests showed that some of these moulds may be virulent and this can be attributed to their possession of some virulence factors, including secretion of hydrolytic enzymes.

The Group A Streptococcus (GAS), also known as Streptococcus pyogenes (S. pyogenes), is a human pathogen causing various infections, ranging from mild, such as tonsillitis and impetigo, to severe and invasive conditions like septicemia and necrotizing fasciitis. Despite a decline in incidence and severity during the twentieth century due to antibiotics, there has been a reported increase in severe cases since the 1980s in industrialized countries. S. pyogenes is a human pathogen with a natural reservoir in the pharynx and skin, exhibits asymptomatic carriage in various body sites. It is responsible for a spectrum of clinical manifestations, from asymptomatic carriage to severe invasive infections. Transmission occurs through respiratory droplets or direct contact with skin lesions. Bacteriologically, S. pyogenes is a Gram-positive β-hemolytic streptococcus. This summary highlights a case of invasive Group A Streptococcus infection in a 28-year-old diagnosed at the microbiology laboratory of the Mohammed V Military Training Hospital in Rabat, Morocco. A 28-year-old patient, without any specific medical history, presented with acute febrile oligoarthritis. Following a recent flu-like syndrome and febrile tonsillitis, the patient experienced asymmetric inflammatory oligoarthralgia affecting the left knee, left ankle, and right shoulder, accompanied by functional impairment of the left lower limb. Upon admission, clinical examination revealed swelling, positive patellar tap, and sternal involvement. Laboratory and imaging findings indicated an abscessed collection in the left knee and anterior mediastinitis. Emergency aspirations revealed Group A Streptococcus, specifically Streptococcus pyogenes, leading to a diagnosis of septic arthritis. Dual antibiotic therapy and knee joint drainage resulted in symptom resolution after 45 days. The rise in severe Group A Streptococcus infection underscores the need for early detection and treatment. Widely sharing the French High Council for Public Health's antibiotic prophylaxis recommendations is crucial for awareness. Collaborating between clinicians and microbiologists is essential for effective management.

To help assess whether a potentially antimicrobial material, surface, or coating provides antimicrobial efficacy, a number of standardised test methods have been developed internationally. Ideally, these methods should generate data that supports the materials efficacy when deployed in the intended end-use application. These methods can be categorised based on their methodological approach such as suspension tests, agar plate/zone diffusion tests, surface inoculation tests, surface growth tests or surface adhesion tests. To support those interested in antimicrobial coating efficacy, this review brings together an exhaustive list of methods (for porous and non-porous materials), exploring the methodological and environmental parameters used to quantify antibacterial, antifungal, or antiviral activity. This analysis demonstrates that antimicrobial efficacy methods that test either fungi or viruses are generally lacking, whilst methods that test bacteria, fungi and viruses are not designed to simulate end-use/lack realistic conditions. As such, a number of applications for antimicrobial activity across medical touch screens, medical textiles and gloves and transport seat textiles are explored as example applications, providing guidance on modifications to existing methods that may better simulate the intended end-use of antimicrobial materials.

Here, we report on the one hundred and twenty-five bacterial strains made available by the National Collection of Type Cultures in 2022 alongside a commentary on the strains, their provenance and significance.

Historically, fuel microbiology studies have relied on culture data. Potentially relevant but unculturable bacteria were not detected. Although ATP can quantify total microbial bioburdens in fuels, it cannot differentiate among the taxa present. Quantitative PCR (qPCR) testing promises to fill this gap by quantifying targeted amplicon sequences thereby detecting both culturable and non-culturable taxa and quantifying specifically targeted taxa. In this study, fluid samples drawn from the fuel, interface and water phases of fuel over water microcosms were tested for cellular ATP concentration ([cATP]) and qPCR bioburdens. Additionally, surface swab samples from steel corrosion coupon surfaces exposed to each of these three phases were collected and tested for total ATP concentration ([tATP]) and qPCR bioburdens. Statistical relationships between ATP and qPCR bioburdens were examined. Correlation coefficients between the two variables were matrix dependent and ranged from negligible (|r|=0.2) to strong (|r|=0.7). When results were categorized into negligible, moderate and heavy bioburdens, parameter agreement was again matrix dependent. Percentage agreement between [ATP] and qPCR gene copies ranged from 11 % to 89 % - with qPCR-bioburden ratings typically being greater than ATP-bioburden ratings.

The hollow-fibre infection model (HFIM) is a valuable in vitro platform for emulating antimicrobial drug pharmacokinetic profiles. Despite its potential, standardized protocols for HFIM operation, especially concerning fastidious organisms, are lacking. This study addresses this gap by examining challenges in culturing Pasteurella multocida and Actinobacillus pleuropneumoniae, two fastidious organisms, in the HFIM. Our findings reveal effective strategies to prevent system clogging, involving multiple freeze-thaw cycles of horse blood, centrifugation and cell straining to enhance the clarity of the Mueller-Hinton fastidious medium defined by the European Committee on Antimicrobial Susceptibility Testing and Clinical and Laboratory Standards Institute. Additionally, we propose that the provision of a CO₂ atmosphere, along with the utilization of gas-permeable tubing and gas vent filters, significantly facilitates the growth of fastidious organisms. Remarkably, both P. multocida and A. pleuropneumoniae were sustained for a period of up to 10 days under these optimized conditions. This study provides crucial insights into the modifications necessary to successfully culture fastidious organisms in the HFIM, paving the way for more accurate and representative in vitro models for antimicrobial drug testing. These advancements hold promise for advancing research in the field of antimicrobial pharmacokinetics and efficacy against challenging pathogens.