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Journal of Bacteriology Oct 1968
Topics: Ampicillin; Bacteroides; Chromatography, Thin Layer; Oxacillin; Penicillin G; Penicillin Resistance; Penicillinase
PubMed: 5686011
DOI: 10.1128/jb.96.4.1437-1438.1968 -
Clinics (Sao Paulo, Brazil) Jan 2015To establish the risk factors for joint infection by oxacillin-resistant Staphylococcus aureus (MRSA) using clinical and epidemiological data.
OBJECTIVE
To establish the risk factors for joint infection by oxacillin-resistant Staphylococcus aureus (MRSA) using clinical and epidemiological data.
METHODS
All septic arthritis cases of the knee and hip diagnosed and treated in our institution from 2006 to 2012 were evaluated retrospectively. Only patients with cultures identified as microbial agents were included in the study. The clinical and epidemiological characteristics of the patients were analyzed, seeking the differences between populations affected by MRSA and oxacillin-sensitive Staphylococcus aureus (MSSA).
RESULTS
S. aureus was isolated in thirty-five patients (46.0%) in our total sample, 25 in the knee and 10 in the hip. Of these 35 patients, 22 presented with MSSA and 13 presented with MRSA. Provenance from a health service-related environment, as described by the Centers for Disease Control and Prevention, was the only variable associated with oxacillin-resistant strains of this bacterium (p = 0.001).
CONCLUSION
Provenance from a health service-related environment was associated with a higher incidence of MRSA-related septic arthritis, suggesting that this agent should be considered in the initial choice of antibiotic treatment. Previous surgeries of the knee or affected limb and the absence of leukocytes might also be related to infection with this agent.
Topics: Adolescent; Adult; Aged; Anti-Bacterial Agents; Arthritis, Infectious; Brazil; Child; Child, Preschool; Hip Joint; Humans; Knee Joint; Male; Middle Aged; Oxacillin; Retrospective Studies; Risk Factors; Staphylococcal Infections; Staphylococcus aureus; Young Adult
PubMed: 25672426
DOI: 10.6061/clinics/2015(01)06 -
MSphere Nov 2018We examined the oxacillin resistance phenotype and genomic structure of staphylococcal cassette chromosome (SCC) elements from 77 veterinary methicillin-resistant...
We examined the oxacillin resistance phenotype and genomic structure of staphylococcal cassette chromosome (SCC) elements from 77 veterinary methicillin-resistant (MRSP) isolates. Isolates were characterized by oxacillin broth microdilution, whole-genome sequencing, and bioformatics analysis. Five previously described SCC elements, and a sixth novel element, were identified: SCC III (also known as II-III), ΨSCC, and SCC (a SCC VII variant), all previously described in MRSP, and SCC IVg and SCC V, previously described in both methicillin-resistant (MRSA) and MRSP. The sixth element was novel and found among nine geographically clustered isolates. This novel pseudostaphylococcal cassette chromosome (ΨSCC) contained a class A gene complex but lacked genes. It also harbored heavy metal (cadmium) resistance determinants. The median oxacillin MIC values among ΨSCC, SCC III, and SCC V isolates were significantly higher than those determined for the SCC VII variant isolates and ΨSCC and SCC IVg isolates. ΨSCC was found exclusively in sequence type 497 (ST497), an MRSP clone that is locally successful in Victoria, Australia. Future studies are necessary to determine if this clone has disseminated further afield and if ΨSCC has moved into other MRSP lineages or staphylococcal species. is a significant veterinary pathogen and occasional cause of infections in humans. β-Lactams are an important group of antimicrobials used to treat staphylococcal infections in humans and animals. However, when staphylococci become methicillin resistant via the acquisition of a mobile genetic element called staphylococcal cassette chromosome (SCC), they become resistant to all β-lactams. This study detected a novel SCC element among a cluster of methicillin-resistant isolates from animals in Australia. It also detected SCC elements in that had high similarity to those identified in methicillin-resistant , demonstrating how human and animal pathogens can share the same resistance determinants.
Topics: Animal Diseases; Animals; Anti-Bacterial Agents; Australia; Chromosomes, Bacterial; Computational Biology; Genomic Islands; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Staphylococcal Infections; Staphylococcus; Whole Genome Sequencing
PubMed: 30404937
DOI: 10.1128/mSphere.00491-18 -
Chemotherapy 2012Staphylococcus saprophyticus is the second most frequent community-acquired causative agent of urinary tract infection (UTI). The objective of this study was to evaluate... (Comparative Study)
Comparative Study
BACKGROUND
Staphylococcus saprophyticus is the second most frequent community-acquired causative agent of urinary tract infection (UTI). The objective of this study was to evaluate the susceptibility profile and resistance detection in Staphylococcus species. isolated from patients with UTI.
MATERIALS AND METHODS
The isolates were investigated using the disk diffusion method, Vitek I system, E-test®, and detection of the mecA gene.
RESULTS
Most isolates (76.2%) were resistant to oxacillin by the disk diffusion method, followed by those resistant to penicillin (72.2%). The oxacillin disk diffusion method, E-test, and Vitek I method showed higher sensitivity (94.4%) and lower specificity (28.9, 26.5, and 24.0%, respectively) than the cefoxitin disk diffusion test (sensitivity: 83.5%, specificity: 85.5%) for the detection of oxacillin resistance.
CONCLUSIONS
The large number of oxacillin-resistant isolates indicates that the breakpoint value recommended by the Clinical and Laboratory Standards Institute may overestimate oxacillin resistance in S. saprophyticus. Thus, changes in these guidelines are necessary for the correct detection of this resistance.
Topics: Anti-Bacterial Agents; Disk Diffusion Antimicrobial Tests; Drug Resistance, Bacterial; Humans; Oxacillin; Practice Guidelines as Topic; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus; Staphylococcus saprophyticus; Urinary Tract Infections
PubMed: 23548376
DOI: 10.1159/000346529 -
Revista Da Sociedade Brasileira de... 2003
Topics: Abscess; Adult; Drainage; Humans; Male; Myositis; Oxacillin; Penicillins; Radiography; Staphylococcal Infections; Staphylococcus aureus
PubMed: 12715072
DOI: 10.1590/s0037-86822003000100017 -
Journal of Global Antimicrobial... Mar 2022Over the past decade, daptomycin treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections has led to the emergence of daptomycin nonsusceptible...
OBJECTIVES
Over the past decade, daptomycin treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections has led to the emergence of daptomycin nonsusceptible (DAP-NS) MRSA strains and a subsequent interest in combinatorial antibiotic therapies. We investigated the phenotypic and genetic changes associated with the seesaw effect, which describes the correlation between daptomycin resistance and increased β-lactam susceptibility in DAP-NS MRSA and the reverse phenomenon of DAP-NS strains acquiring renewed susceptibility to daptomycin after β-lactam exposure.
METHODS
A continuous bioreactor model was used to study the effects of incremental doses of daptomycin followed by oxacillin on MRSA strain N315. Minimum inhibitory concentrations for daptomycin and oxacillin were determined for the bioreactor-derived samples. Transmission electron microscopy and cytochrome C binding assays were used to measure cell wall thickness and cell membrane charge, respectively, in the bioreactor-derived samples. Whole-genome sequencing was used to identify mutations associated with the seesaw effect.
RESULTS
Although daptomycin resistance conferred enhanced susceptibility to oxacillin, oxacillin treatment of DAP-NS strains was accompanied by a lowered minimum inhibitory concentration for daptomycin. Additionally, there was a reduction in relative positive cell surface charge and cell wall thickness. However, the mutations acquired in our DAP-NS populations were not accompanied by additional genomic changes after treatment with oxacillin, implicating alternative mechanisms for the seesaw effect.
CONCLUSION
In this study, we successfully produced and characterized the seesaw effect in MRSA strain N315 in a unique bioreactor model.
Topics: Bioreactors; Daptomycin; Methicillin-Resistant Staphylococcus aureus; Oxacillin; beta-Lactams
PubMed: 35085792
DOI: 10.1016/j.jgar.2022.01.013 -
Diagnostic Microbiology and Infectious... Oct 2022Use of the Biolog OmniLog® phenotyping system for antibiotic susceptibility testing (AST) was evaluated using 51 clinical isolates of Staphylococcus aureus. MIC testing...
Use of the Biolog OmniLog® phenotyping system for antibiotic susceptibility testing (AST) was evaluated using 51 clinical isolates of Staphylococcus aureus. MIC testing by broth microdilution was compared to results generated using the OmniLog® system for oxacillin, daptomycin, vancomycin, gentamicin, linezolid, and tetracycline. There was >90% essential and categorical agreement between methods for all antibiotics, except gentamicin, which had 83.6% essential agreement, although very major errors occurred with linezolid (n = 3) and daptomycin (n = 1). Precision was satisfactory, with 5 triplicate measurements in agreement. A quantitative threshold allowed automated interpretation of MICs yielding results comparable to manual interpretation; oxacillin, gentamicin, and tetracycline resistance could be identified at a median of 7.13, 5.25, and 7.25 hours, respectively. Limitations include the small number of isolates, and especially resistant isolates tested, and the focus on a single species. Overall, the OmniLog® system was a precise method for AST of S. aureus, although accuracy was imperfect.
Topics: Anti-Bacterial Agents; Daptomycin; Gentamicins; Linezolid; Microbial Sensitivity Tests; Oxacillin; Staphylococcal Infections; Staphylococcus aureus
PubMed: 35872370
DOI: 10.1016/j.diagmicrobio.2022.115759 -
MBio Dec 2020Antistaphylococcal penicillins such as oxacillin are the key antibiotics in the treatment of invasive methicillin-susceptible (MSSA) infections; however,...
Antistaphylococcal penicillins such as oxacillin are the key antibiotics in the treatment of invasive methicillin-susceptible (MSSA) infections; however, gene-independent resistance adaptation can cause treatment failure. Despite its clinical relevance, the basis of this phenomenon remains poorly understood. Here, we investigated the genomic adaptation to oxacillin at an unprecedented scale using a large collection of 503 clinical -negative isolates and 30 -adapted isolates from independent oxacillin exposures. By combining comparative genomics, evolutionary convergence, and genome-wide association analysis, we found 21 genetic loci associated with low-level oxacillin resistance, underscoring the polygenic nature of this phenotype. Evidence of adaptation was particularly strong for the c-di-AMP signal transduction pathways ( and ) and in the chaperone-protease complex. The role of mutations in in conferring low-level oxacillin resistance was confirmed by allele-swapping experiments. We found that resistance to oxacillin emerges at high frequency (median, 2.9 × 10; interquartile range [IQR], 1.9 × 10 to 3.9 × 10), which is consistent with a recurrent minimum inhibitory concentration (MIC) increase across the global phylogeny of clinical isolates. Nevertheless, adaptation in clinical isolates appears sporadically, with no stably adapted lineages, suggesting a high fitness cost of resistance, confirmed by growth assessment of mutants in rich media. Our data provide a broader understanding of the emergence and dynamics of oxacillin resistance adaptation in and a framework for future surveillance of this clinically important phenomenon. The majority of strains causing human disease are methicillin-susceptible (MSSA) and can be treated with antistaphylococcal penicillins (such as oxacillin). While acquisition of the gene represents the main resistance mechanism to oxacillin, can acquire low-level resistance through adaptive mutations in other genes. In this study, we used genomic approaches to understand the basis of adaption to oxacillin and its dynamic at the population level. By combining a genome analysis of clinical isolates from persistent MSSA infections, selection of oxacillin resistance, and genome-wide association analysis on a large collection of isolates, we identified 21 genes linked to secondary oxacillin resistance. Adaptive mutations in these genes were easy to select when was exposed to oxacillin, but they also came at a substantial cost in terms of bacterial fitness, suggesting that this phenotype emerges preferentially in the setting of sustained antibiotic exposure.
Topics: Adaptation, Biological; Anti-Bacterial Agents; Bacterial Proteins; Drug Resistance, Bacterial; Genome, Bacterial; Genomics; Humans; Methicillin-Resistant Staphylococcus aureus; Mutation; Oxacillin; Staphylococcal Infections; Staphylococcus aureus
PubMed: 33293382
DOI: 10.1128/mBio.02882-20 -
Microbiology Spectrum Aug 2023Methicillin-resistant Staphylococcus aureus (MRSA) is a clinical threat with high morbidity and mortality. Here, we describe a new simple, rapid identification method...
Methicillin-resistant Staphylococcus aureus (MRSA) is a clinical threat with high morbidity and mortality. Here, we describe a new simple, rapid identification method for MRSA using oxacillin sodium salt, a cell wall synthesis inhibitor, combined with Gram staining and machine vision (MV) analysis. Gram staining classifies bacteria as positive (purple) or negative (pink) according to the cell wall structure and chemical composition. In the presence of oxacillin, the integrity of the cell wall for methicillin-susceptible S. aureus (MSSA) was destroyed immediately and appeared Gram negative. In contrast, MRSA was relatively stable and appeared Gram positive. This color change can be detected by MV. The feasibility of this method was demonstrated in 150 images of the staining results for 50 clinical S. aureus strains. Based on effective feature extraction and machine learning, the accuracies of the linear linear discriminant analysis (LDA) model and nonlinear artificial neural network (ANN) model for MRSA identification were 96.7% and 97.3%, respectively. Combined with MV analysis, this simple strategy improved the detection efficiency and significantly shortened the time needed to detect antibiotic resistance. The whole process can be completed within 1 h. Unlike the traditional antibiotic susceptibility test, overnight incubation is avoided. This new strategy could be used for other bacteria and represents a new rapid method for detection of clinical antibiotic resistance. Oxacillin sodium salt destroys the integrity of the cell wall of MSSA immediately, appearing Gram negative, whereas MRSA is relatively stable and still appears Gram positive. This color change can be detected by microscopic examination and MV analysis. This new strategy has significantly reduced the time to detect resistance. The results show that using oxacillin sodium salt combined with Gram staining and MV analysis is a new, simple and rapid method for identification of MRSA.
Topics: Humans; Methicillin-Resistant Staphylococcus aureus; Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Methicillin; Staining and Labeling; Anti-Bacterial Agents; Staphylococcal Infections
PubMed: 37395643
DOI: 10.1128/spectrum.05282-22 -
International Journal of Molecular... Oct 2022Raman spectra of oxacillin (OXN), carbenicillin (CBC), and azlocillin (AZL) are reported for the first time together with their full assignment of the normal modes, as...
Raman spectra of oxacillin (OXN), carbenicillin (CBC), and azlocillin (AZL) are reported for the first time together with their full assignment of the normal modes, as calculated using Density Functional Theory (DFT) methods with the B3LYP exchange-correlation functional coupled to the 6-31G(d) and 6-311+G(2d,p) basis sets. Molecular docking studies were performed on five penicillins, including OXN, CBC, and AZL. Subsequently, their chemical reactivity and correlated efficiency towards specific pathogenic strains were revealed by combining frontier molecular orbital (FMO) data with molecular electrostatic potential (MEP) surfaces. Their bactericidal activity was tested and confirmed on a couple of species, both Gram-positive and Gram-negative, by using the disk diffusion method. Additionally, a surface-enhanced Raman spectroscopy (SERS)-principal component analysis (PCA)-based of is proposed as a clinically relevant insight resulting from the synergistic cheminformatics and vibrational study on CBC and AZL.
Topics: Spectroscopy, Fourier Transform Infrared; Models, Molecular; Cheminformatics; beta-Lactams; Molecular Docking Simulation; Azlocillin; Spectrum Analysis, Raman; Static Electricity; Vibration; Carbenicillin; Oxacillin; Quantum Theory; Thermodynamics
PubMed: 36293563
DOI: 10.3390/ijms232012685