Determination of the Pattern of Resistance to Antibiotics among Strains of Staphylococcus aureus Isolated from the Nose or Pharynx †
by
Samuel González-García
1,*, 
Aida Hamdan-Partida
2,
Anaid Bustos-Hamdan
3 and
Jaime Bustos-Martínez
2 1
División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, Mexico City 04960, Mexico
2
Departamento Atención a la Salud, Universidad Autónoma Metropolitana-Xochimilco, Mexico City 04960, Mexico
3
Instituto Nacional de Perinatología, Mexico City 11000, Mexico
*
Author to whom correspondence should be addressed.
†
Presented at the 2nd International Electronic Conference on Antibiotics—Drugs for Superbugs: Antibiotic Discovery, Modes of Action and Mechanisms of Resistance, 15–30 June 2022; Available online: https://eca2022.sciforum.net/ .
Med. Sci. Forum 2022, 12(1), 38; https://doi.org/10.3390/eca2022-12720
Published: 15 June 2022
(This article belongs to the Proceedings of The 2nd International Electronic Conference on Antibiotics—Drugs for Superbugs: Antibiotic Discovery, Modes of Action and Mechanisms of Resistance)
The pathophysiology of Staphylococcus aureus in nasal carriers has been extensively studied, however, it must be admitted that the clinical relevance of S. aureus carriers in the pharynx has not been extensively investigated. S. aureus can be commonly found in other body sites such as the axillae (8%), chest/abdomen (15%), perineum (22%), intestine (17–31%), vagina (5%) and from 4 to 64% in the pharynx.
The objective of the work was to determine if there are differences in the pattern of resistance to antibiotics of strains isolated from the nose and pharynx.
Pharyngeal and nasal exudates were performed on 98 university students once a month for three months. All strains that were coagulase-positive mannitol fermenters were identified as S. aureus. If a person presented three isolates of S. aureus, they were considered persistent carriers, if they presented one or two isolates in a row, they were considered intermittent carriers, and if the bacteria were never isolated, they were considered non-carriers.
All strains of S. aureus underwent antibiogram against ciprofloxacin, fosfomycin, trimethoprim-sulfamethoxazole, penicillin, vancomycin, tetracycline, erythromycin, oxacillin, clindamycin, gentamicin, and cephalothin by the Kirby-Bauer method and minimum inhibitory concentration (MIC) for oxacillin, following the indications of the CLSI.
A total of 81 strains of S. aureus were isolated from the pharynx and 43 strains from the nose of the students during the three samples taken. In the case of the pharyngeal strains, 81.4% were resistant to penicillin, 12.5% to clindamycin, 8.6% to erythromycin, 2.78% they are resistant to tetracycline and oxacillin. For ciprofloxacin, fosfomycin, vancomycin, gentamicin, and cephalothin, the percentage of resistant strains was less than 1%.
In the case of the strains isolated from the nose, it was found that 84.3% are resistant to penicillin, 18.2% to erythromycin, 12.4% to clindamycin, 4.49% to tetracycline, 3.6% were resistant to oxacillin. For ciprofloxacin, fosfomycin, trimethoprim-sulfamethoxazole, gentamicin, and cephalothin, the percentage of resistant strains was less than 1%.
More strains of S. aureus were isolated from the pharynx than from the nose. No differences were found in resistance to antibiotics, nor changes in the percentage of resistant strains in the pharynx and nose.
Supplementary Materials
The following are available online at https://www.mdpi.com/article/10.3390/eca2022-12720/s1.
Author Contributions
Conceptualization, S.G.-G., A.H.-P. and J.B.-M.; methodology, S.G.-G., A.H.-P. and A.B.-H.; formal analysis, S.G.-G., A.H.-P. and A.B.-H.; writing—original draft preparation, S.G.-G., A.H.-P. and J.B.-M.; writing—review and editing S.G.-G., A.H.-P., A.B.-H. and J.B.-M. All authors have read and agreed to the published version of the manuscript.
Funding
This work was support by Special Research Support Program of UAM.
Institutional Review Board Statement
The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Ethics Committee and the Research Committee of the Division of Biological and Health Sciences of the Universidad Autónoma Metropolitana-Xochimilco within the project: “Molecular characterization of Staphylococcus aureus strains isolated in healthy carriers of the Mexican community” in the 1/18 session held on 8 February 2018. The identification code is DCBS.CD.056.18.
Informed Consent Statement
Informed consent was obtained from all subjects involved in the study.
Data Availability Statement
Not applicable.
Conflicts of Interest
The authors declare no conflict of interest.
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MDPI and ACS Style
González-García, S.; Hamdan-Partida, A.; Bustos-Hamdan, A.; Bustos-Martínez, J. Determination of the Pattern of Resistance to Antibiotics among Strains of Staphylococcus aureus Isolated from the Nose or Pharynx. Med. Sci. Forum 2022, 12, 38. https://doi.org/10.3390/eca2022-12720
AMA Style
González-García S, Hamdan-Partida A, Bustos-Hamdan A, Bustos-Martínez J. Determination of the Pattern of Resistance to Antibiotics among Strains of Staphylococcus aureus Isolated from the Nose or Pharynx. Medical Sciences Forum. 2022; 12(1):38. https://doi.org/10.3390/eca2022-12720
Chicago/Turabian StyleGonzález-García, Samuel, Aida Hamdan-Partida, Anaid Bustos-Hamdan, and Jaime Bustos-Martínez. 2022. "Determination of the Pattern of Resistance to Antibiotics among Strains of Staphylococcus aureus Isolated from the Nose or Pharynx" Medical Sciences Forum 12, no. 1: 38. https://doi.org/10.3390/eca2022-12720
