We previously reported that deficiency of the lytH gene, whose product is homologous to lytic enzymes, caused the elevation of methicillin resistance in Staphylococcus aureus strain SR17238, a strain of S. aureus with a low level of resistance to methicillin (low-level MRSA) (J. Bacteriol. 179:6294-6301, 1997). In this study, we demonstrated that deficiency of lytH caused the same phenomenon in four other clinical isolates of low-level MRSA, suggesting this deficiency to exist in clinical isolates. We therefore searched the region including lytH in 127 clinical isolates of MRSA by PCR and found one strain, SR17164 (methicillin MIC, 1,600 microg/ml), in which the lytH gene was inactivated by insertion sequence IS1182. lytH::IS1182 was replaced with intact lytH in this strain by integration and excision of the plasmid carrying the lytH region. Recombinants with intact lytH genes showed methicillin MICs of 800 microg/ml, twofold lower than those of the recombinants with lytH::IS1182 and the parent. In addition, S. aureus SR17164, which has a high level of methicillin resistance, had properties similar to those caused by lytH deficiency; that is, the resistance levels of strain SR17164 and lytH-deficient variants from strain SR17238 were not significantly affected by llm inactivation, which greatly lowered resistance levels in most other high-level MRSA strains. These findings suggest that lytH inactivation contributed, to some extent, to the resistance level of S. aureus SR17164. To the best of our knowledge, this strain is the first clinical isolate of MRSA for which the genetic base for high-level resistance has been clarified.
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http://dx.doi.org/10.1128/AAC.00395-07 | DOI Listing |
Bioact Mater
April 2025
Department of Orthopedic Trauma and Microsurgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, PR China.
Chronic osteomyelitis caused by implant infections is a common complication following orthopedic surgery. Preventing bacterial infection and simultaneously improving bone regeneration are the key for osteomyelitis. Current treatments include systemic antibiotics and multiple surgical interventions, but the strategies available for treatment are limited.
View Article and Find Full Text PDFHeliyon
January 2025
Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran.
Cockroaches are widely recognized as vectors for transmitting pathogenic microorganisms in hospital and community environments due to their movement between contaminated and human-occupied spaces. (. ), particularly methicillin-resistant (MRSA), is a primary global health concern because of its capacity to cause a wide range of infections and its resistance to many antibiotics.
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January 2025
Center for Health Equity and Innovation, Cook County Health, Chicago, IL, USA.
Objective: We aimed to determine whether benchmarking antimicrobial use (AU) to antimicrobial resistance (AR) using select AU/AR ratios is more informative than AU metrics in isolation.
Design: We retrospectively measured AU (antimicrobial therapy days per 1,000 days present) and AU/AR ratios (specific antimicrobial therapy days per corresponding AR event) in two hospitals during 2020 through 2022. We then had antimicrobial stewardship committee members evaluate each AU and corresponding AU/AR value and indicate whether they believed it represented potential overuse, appropriate use, or potential underuse of the antimicrobials, or whether they could not provide an assessment.
Int J Biol Macromol
January 2025
Guangxi Key Laboratory of Natural Polymer Chemistry and Physics, Nanning Normal University, Nanning 530000, China. Electronic address:
Due to resistance to common antibiotics, methicillin-resistant Staphylococcus aureus (MRSA) infections pose a significant threat to human health. In this study, we developed an injectable, adhesive, and biocompatible hydrogel with multiple functions. Specifically, carboxymethyl chitosan (CMCS) crosslinked with hyaluronic acid (HA) forms the primary framework of the hydrogel.
View Article and Find Full Text PDFCarbohydr Res
January 2025
Faculty of Chemistry, University of Wrocław, Wrocław, 50-383, Poland.
Triggered by the urgent need to tackle the global crisis of multidrug-resistant bacterial infections, in this work, we present a way to overcome chloramphenicol resistance by introducing modifications based on the glycosylation of its hydroxyl groups. The synthesized derivatives demonstrate complete resistance to the action of recombinant chloramphenicol acetyltransferase (CAT) from Escherichia coli and efficacy against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli ESBL, and Pseudomonas aeruginosa ATCC 27853. Glycosylation gives chloramphenicol an additional advantage - the stable glycosidic form is less toxic to human dermal fibroblasts and has significantly better water solubility than non-glycosylated chloramphenicol.
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