Dataset Information

Detection of Oxacillin/Cefoxitin Resistance in Staphylococcus aureus Present in Recurrent Tonsillitis.

ABSTRACT:

Background

Recurrent tonsillitis is one of the most common diseases in childhood, caused many times by ß-lactam-resistant S. aureus. The objective of this study was to investigate an alternative method to identify resistance to oxacillin/cefoxitin in S. aureus from hospitalized children with recurrent tonsillitis.

Methods

The samples of S. aureus came from patients with recurrent tonsillitis and were used in 16S rRNA sequencing and an antibiogram test for identification and verifying resistance, after which HSI methodology were applied for separation of S. aureus resistances.

Results

The S. aureus isolated showed sensitivity to oxacillin/cefoxitin and the diagnostic images show a visual description of the resistance different groups formed, that may be related to sensitivity and resistance to oxacillin/cefoxitin, characterizing the MRSA S. aureus.

Conclusions

Samples that showed phenotypic resistance to oxacillin/cefoxitin were clearly separated from samples that did not show this resistance. A PLS-DA model predicted the presence of resistance to oxacillin/cefoxitin in S. aureus samples and it was possible to observe the pixels classified as MRSA. The HSI was able to successfully discriminate samples in replicas that were sensitive and resistant, based on the calibration model it received.

SUBMITTER: Messias ACMC

PROVIDER: S-EPMC10055619 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Detection of Oxacillin/Cefoxitin Resistance in <i>Staphylococcus aureus</i> Present in Recurrent Tonsillitis.

Messias Aline Cristine Magalhães Costa ACMC Gama Aline Rodrigues AR de Almeida Prado Letícia Suriano LS da Silva Paulo Alex Neves PAN Galvão Filho Arlindo Rodrigues AR Coelho Clarimar José CJ Avelino Melissa Ameloti Gomes MAG Vieira José Daniel Gonçalves JDG Carneiro Lilian Carla LC

Microorganisms 20230228 3

<h4>Background</h4>Recurrent tonsillitis is one of the most common diseases in childhood, caused many times by ß-lactam-resistant <i>S. aureus</i>. The objective of this study was to investigate an alternative method to identify resistance to oxacillin/cefoxitin in <i>S. aureus</i> from hospitalized children with recurrent tonsillitis.<h4>Methods</h4>The samples of <i>S. aureus</i> came from patients with recurrent tonsillitis and were used in 16S rRNA sequencing and an antibiogram test for iden ...[more]

PMID: 36985189

Similar Datasets

Project description:The oxacillin- and cefoxitin-susceptible mecA-positive Staphylococcus aureus is a novel "stealth" methicillin-resistant S. aureus (MRSA) type. Here, we sequenced the whole genome of two oxacillin- and cefoxitin-susceptible mecA-positive MRSA isolates from breast abscesses in a lactating woman and a nasal swab of a healthy student in Guangzhou for investigating the mechanism underlying its occurrence. The reversion of these isolates was selected by exposure to sub-MICs of cefoxitin with or without mupirocin. The mecA expression of both parental strains and their revertants was determined, and the whole genome of the revertants was sequenced. Comparative whole-genome analyses performed for both strains revealed that mecA of the clinical strain was mutated by a single-bp insertion at the 262nd position in the tandem repeat region of the gene, and this mutation that led to the formation of a premature stop codon. The colonizing strain was mutated by a novel G-to-A base substitution in the second promoter region (-35 bp) of mecA. The mecA expression level of strain 697 revertant was 37 times higher than that of the parental strain. Although the mecA expression level was even higher for parental strain 199 compared with that for its revertant, its cDNA sequence contained a single-bp insertion. Collectively, both the missense and single substitution mutations of the second promoter of mecA could render MRSA isolates as "stealth" MRSA, thereby emphasizing the importance of combining phenotype tests with mecA or penicillin-binding protein 2a detection for the identification of MRSA. IMPORTANCE The oxacillin- and cefoxitin-susceptible mecA-positive Staphylococcus aureus is a novel type of "stealth" methicillin-resistant S. aureus (MRSA), which is difficult to be detected using conventional methods. To investigate the genomic basis of their occurrence, we sequenced the whole genome of two previously recovered oxacillin- and cefoxitin-susceptible mecA-positive MRSA isolates from breast abscesses in a lactating woman and a nasal swab of a healthy student in Guangzhou. Complete SCCmec structure was absent except for mecA in clinical isolate 199. Additionally, a novel single-base pair insertion was observed in the clinical strain, which resulted in premature termination and a frameshift mutation. The colonizing isolate 697 had a Scc-mec-type IVa, and the second promoter region (-35 bp) of mecA was mutated by a novel G-to-A base substitution. The reversion of oxacillin- and cefoxitin-susceptible mecA-positive S. aureus to resistant MRSA isolates was selected by exposure to subminimum inhibitory cefoxitin with or without mupirocin.