Emerging Resistance and Virulence Patterns in <i>Salmonella enterica</i>: Insights into Silver Nanoparticles as an Antimicrobial Strategy

Emerging Resistance and Virulence Patterns in <i>Salmonella enterica</i>: Insights into Silver Nanoparticles as an Antimicrobial Strategy

Background/Objectives: This study aims to characterize antibiotic resistance (AR) and virulence markers in <i>Salmonella</i> spp. isolated from Romanian outpatients’ stool samples. Methods: In 2019, community-acquired <i>Salmonella</i> strains were collected and identified us...

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Main Authors: Irina Gheorghe-Barbu, Ilda Czobor Barbu, Rareș-Ionuț Dragomir, Ioana Cristina Marinaș, Miruna Silvia Stan, Radu Pericleanu, Andreea Ștefania Dumbravă, Liviu-Iulian Rotaru, Simona Paraschiv, Leontina Mirela Bănică, Ionuț Pecete, Dan Oțelea, Violeta Corina Cristea, Mircea Ioan Popa, Marilena Monica Țânțu, Marius Surleac
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Antibiotics
Subjects:
salmonellosis
<i>Salmonella enterica</i> Typhimurium
paediatric patients
alternative antimicrobial solutions based on silver nanoparticles
Online Access:https://www.mdpi.com/2079-6382/14/1/46
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Summary:Background/Objectives: This study aims to characterize antibiotic resistance (AR) and virulence markers in <i>Salmonella</i> spp. isolated from Romanian outpatients’ stool samples. Methods: In 2019, community-acquired <i>Salmonella</i> strains were collected and identified using MALDI-TOF mass spectrometry, antibiotic susceptibility profiles have been determined with the MicroScan system, and soluble virulence factors were evaluated using specific culture media, while biofilm formation was quantified in 96-well plates. Molecular analysis targeted resistance genes for β-lactams (e.g., <i>bla</i><sub>TEM</sub> and <i>bla</i><sub>SHV</sub>); tetracyclines (e.g., <i>tet(A)</i>); sulphonamides; and quinolones, as well as virulence genes (e.g., <i>invA</i>, <i>spvC</i>, <i>pldA</i>, and <i>held</i>). Whole-genome sequencing (WGS) was performed on 19 selected isolates. A silver nanoparticles (AgNPsol) alternative to conventional antibiotics was tested for effectiveness against multidrug-resistant (MDR) isolates. Results: From the total of 309 <i>Salmonella</i> isolates (65.05% from children under 4 years of age) belonging to four subtypes and four serovars, 27.86% showed resistance to at least one antibiotic, most frequently to tetracycline, ampicillin, and piperacillin. The strains frequently expressed haemolysin (67%), aesculinase (65%), and gelatinase (62%). Resistance to trimethoprim-sulfamethoxazole was encoded by the <i>sul1</i> gene in 44.83% of the strains and to tetracyclines by the <i>tet(A)</i> gene (59.52%). The ESBL genes <i>bla</i><sub>TEM</sub>, <i>bla</i><sub>SHV</sub>, and <i>bla</i><sub>CTX-M</sub> were detected by PCR in 16.18%, 2.91%, and 0.65% of the strains, respectively. Additionally, 98.63% of the strains carried the <i>invA</i> marker, with notable positive associations between <i>bla</i><sub>SHV</sub>, <i>qnrB</i>, and <i>sul1</i> with <i>spvC</i>. Conclusions: The present findings revealed significant patterns in <i>Salmonella</i> isolates, subtypes, serovars, AR, and virulence, emphasising the need for continuous surveillance of <i>Salmonella</i> infections. Additionally, the potential of AgNPs as an alternative treatment option was demonstrated, particularly for paediatric <i>S. enterica</i> infections.
ISSN:2079-6382

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