Variants of large colony beta-haemolytic Lancefield group A, C and G streptococci that are non-haemolytic or alpha-haemolytic on sheep blood agar have been detected in clinical specimens due to their enhanced haemolytic activity when grown on a new selective and differential blood agar medium containing colistin, nalidixic acid and pH 7.5-adjusted PIPES buffer (CNA-P). The large colony Lancefield group C and G isolates were identified as Streptococcus dysgalactiae subsp. equisimilis by API 20 Strep classification and 16S rDNA profiling. The haemolytic activity of these variants on various blood agar media, including CNA-P, was closely similar to that of known streptolysin S-defective mutants of S. pyogenes and was blocked by addition of cholesterol, a specific inhibitor of the streptolysin O family of haemolysins. As haemolysin variants could be detected in large numbers in cultures from patients with clinical symptoms of pharyngitis it is suggested that they may function as primary pathogens in such infections. The high frequency with which haemolysin variants were isolated from clinical specimens during a 3-month trial (3%, 13% and 10%, respectively, of group A, C and G streptococcal isolates) indicated that a substantial proportion of streptococcal infections may go undetected if only conventional sheep blood agar media are used in clinical laboratories for the detection of beta-haemolytic streptococci. As haemolysin variants have been implicated in the development of serious streptococcal sequelae, further investigation of the full extent of their contribution to streptococcal disease is indicated.
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http://dx.doi.org/10.1099/0022-1317-49-9-811 | DOI Listing |
Cureus
November 2024
Microbiology, Kalinga Institute of Medical Sciences, Bhubaneswar, IND.
Background And Objectives: Stroke-associated pneumonia (SAP) is the aftermath of aspiration of oropharyngeal secretions or stomach content. Mechanical ventilation and lowered immunity and consciousness facilitate the etiopathogenesis of SAP. Antibiotic prophylaxis and repeated culture and sensitivity testing dampen the drug susceptibility patterns of the pathogens.
View Article and Find Full Text PDFBMC Oral Health
December 2024
Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China.
Background: IFN-γ is crucial in induction of inducible cell-autonomous immunity, and IFN-γ signaling pathway is activated in pulpitis. Guanylate-binding proteins (GBPs) are a family of IFN-inducible GTPases and could utilize autophagy or pyroptosis to mitigate infection. GBP5 is abundantly expressed in inflamed pulp and human dental pulp cells (HDPCs).
View Article and Find Full Text PDFJ Appl Microbiol
December 2024
Department of Biological and Chemical Engineering, Aarhus University, 8000 Aarhus C, Denmark.
Aim: Aeromonas spp. are common members of water and wastewater microbiomes but some are listed as opportunistic pathogens and are often reported to carry antimicrobial resistance (AMR) genes. We aimed to assess the performance of isolation media for capturing their distribution and their role in AMR dissemination into aquatic environments.
View Article and Find Full Text PDFJ Hosp Infect
December 2024
Infectious Diseases Service, Hospital Clínic Barcelona, Institut d'Investigacions Biomèdiques Augusto Pi I Sunyer (IDIBAPS), Barcelona, Spain. Electronic address:
Background: We evaluated the microbial burden on gel polished nails (GPN), standard polished nails (SPN) and unpolished nails (UPN) before and after an alcohol-based hand rub (HHAB).
Methods: Three GPN, two SPN and five UPN in both hands were analyzed in 46 health-care workers volunteers. Nail length was maintained ≤2mm during the study.
Access Microbiol
September 2024
Graduate School of Health Sciences, Hirosaki University, Hon-cho 66-1, Hirosaki, Aomori, 036-8564, Japan.
The string test is a screening method for detecting hypervirulent (hvKp). Agar media are used for string tests; however, the effect of the type of media on the test results remains unclear. We aimed to determine the optimal agar medium and cutoff value for the string test.
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