Antibiotic resistance and the new antibiotic agents

Abstract Background Resistant Staphylococcus aureus (S. aureus) bacteria are considered among the major causes of foodborne diseases. This survey aims to assess genotypic and phenotypic profiles of antibiotic resistance in S. aureus bacteria isolated from ready-to-eat food samples. Methods According to the previously reported prevalence of S. aureus in ready-to-eat food samples, a total of 415 ready-to-eat food samples were collected from Tehran province, Iran. S. aureus bacteria were identified using culture and biochemical tests. Besides, the phenotypic antibiotic resistance profile was determined by disk diffusion. In addition, the genotypic pattern of antibiotic resistance was determined using the PCR. Results A total of 64 out of 415 (15.42%) ready-to-eat food samples were contaminated with S. aureus. Grilled mushrooms and salad olivieh harbored the highest contamination rate of (30%), while salami samples harbored the lowest contamination rate of 3.33%. In addition, S. aureus bacteria harbored the highest prevalence of resistance to penicillin (85.93%), tetracycline (85.93%), gentamicin (73.43%), erythromycin (53.12%), trimethoprim-sulfamethoxazole (51.56%), and ciprofloxacin (50%). However, all isolates were resistant to at least four antibiotic agents. Accordingly, the prevalence of tetK (70.31%), blaZ (64.06%), aacA-D (57.81%), gyrA (50%), and ermA (39.06%) was higher than that of other detected antibiotic resistance genes. Besides, AacA-D + blaZ (48.43%), tetK + blaZ (46.87%), aacA-D + tetK (39.06%), aacA-D + gyrA (20.31%), and ermA + blaZ (20.31%) were the most frequently identified combined genotypic patterns of antibiotic resistance. Conclusion Ready-to-eat food samples may be sources of resistant S. aureus, which pose a hygienic threat in case of their consumption. However, further investigations are required to identify additional epidemiological features of S. aureus in ready-to-eat foods.

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The role of stereochemistry of antibiotic agents in the development of antibiotic resistance in the environment

Environment International ◽

10.1016/j.envint.2020.105681 ◽

2020 ◽

Vol 139 ◽

pp. 105681 ◽

Cited By ~ 2

Author(s):

Felicity C.T. Elder ◽

Edward J. Feil ◽

JasoN. Snape ◽

William H. Gaze ◽

BarbarA. Kasprzyk-Hordern

Keyword(s):

Antibiotic Resistance ◽

Antibiotic Agents

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Antimicrobial Resistance Properties of Staphylococcus Aureus Isolates From Powdered Packaged Medicinal Plants and Bottle Herbal Distillates

10.21203/rs.3.rs-116659/v1 ◽

2020 ◽

Author(s):

Zohreh Mashak ◽

Bahareh Tavakoli-Far

Keyword(s):

Staphylococcus Aureus ◽

Antibiotic Resistance ◽

Medicinal Plants ◽

Medicinal Plant ◽

Antibiotic Resistance Genes ◽

Culture Method ◽

Multidrug Resistant ◽

Contamination Rate ◽

Pcr Techniques ◽

Antibiotic Agents

Abstract BackgroundHuman involvement in the production and processing of medicinal plants and herbal distillates caused a potential risk of microbial contamination, particularly with Staphylococcus aureus. The present research was performed to assess the prevalence and phenotypic and genotypic properties of antibiotic resistance of S. aureus bacteria isolated from diverse kinds of powdered packaged medicinal plant and bottle herbal distillate samples. MethodsThree-hundred different powdered packaged medicinal plant and bottle herbal distillate samples produced in traditional conditions were collected and examined by the culture method. Phenotypic and genotypic patterns of antibiotic resistance of S. aureus isolates were examined using disk diffusion and PCR techniques. ResultsThirty out of three-hundred (10%) powdered packaged medicinal plant and bottle herbal distillate samples were contaminated with S. aureus. The prevalence of S. aureus amongst the powdered packaged medicinal plant and bottle herbal distillate samples were 8.33% and 11.11%, respectively. A. citrodora (10%) and R. damascene (10%) powdered packed medicinal plants and A. maurorum (16.66%) bottle herbal distillate had the highest contamination rate with S. aureus. S. aureus isolates harbored the highest prevalence of resistance toward penicillin (93.33%), tetracycline (90%), gentamicin (86.66%), erythromycin (70%), trimethoprim-sulfamethoxazole (63.33%) and ciprofloxacin (53.33%). Totally, 13.33% of the S. aureus isolates harbored resistance toward more than 7 antibiotic agents. blaZ (63.33%), tetK (60%), ermA (46.66%), msrA (43.33%), aacA-D (43.33%), and mecA (43.33%) were the most frequent antibiotic resistance genes. ConclusionsPowdered packaged medicinal plant and bottle herbal distillate samples may be sources of multidrug resistant-S. aureus, which poses a hygienic threat concerning the consumption of these therapeutic options in Iran. Nevertheless, further research is compulsory to understand other epidemiological features of S. aureus in powdered packaged medicinal plant and bottle herbal distillate samples.

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Molecular Typing and Phenotypic and Genotypic Evaluation of Antibiotic Resistance and Virulence Factors of the Methicillin-Resistant Staphylococcus Aureus Bacteria Isolated From Vegetable and Salad Samples

10.21203/rs.3.rs-116662/v1 ◽

2020 ◽

Author(s):

Bahareh Tavakoli-Far ◽

Bita Mousavi ◽

Zohreh Mashak ◽

Mohammad Adel Rezaei ◽

Fatemeh Doregiraee ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Antibiotic Resistance ◽

Virulence Factors ◽

Resistance Genes ◽

Molecular Typing ◽

Antibiotic Resistance Genes ◽

Disk Diffusion ◽

Bacteria Resistance ◽

Antibiotic Agents ◽

Antibiotic Resistance Properties

Abstract BackgroundMethicillin-resistant Staphylococcus aureus is an important cause of foodborne diseases. The present research evaluated the antibiotic resistance properties, distribution of virulence factors, and molecular typing of MRSA bacteria isolated from vegetable and salad samples. MethodsThree-hundred and fifty vegetable and salad samples were examined for the presence of S. aureus using the culture. MRSA bacteria were identified using cefoxitin and oxacillin disk diffusion. The phenotypic pattern of antibiotic resistance was assessed by disk diffusion. ResultsThe PCR evaluated the distribution of antibiotic resistance and virulence genes. Forty-five out of 350 (12.85%) vegetable and salad samples were positive for S. aureus. Twenty-six isolates out of 45 (57.77%) S. aureus bacteria were determined as MRSA. MRSA bacteria harbored the uppermost prevalence of resistance against cefoxitin (100%), ceftaroline (100%), penicillin (100%), tetracycline (88.46%), gentamicin (80.76%), trimethoprim-sulfamethoxazole (69.23%), and erythromycin (69.23%). The prevalence of MRSA bacteria resistance recovered from vegetable and salad samples against more than seven antibiotic agents was 12.50% and 27.77%, respectively. BlaCTX-M (100%), blaZ (100%), aacA-D (61.53%), tetK (57.69%), dfrA1 (46.15%), and vanA (42.30%) were the most commonly detected antibiotic resistance genes. PVL (57.69%), coa (53.84%), and hla (38.46%) were the most commonly detected virulence factors amongst the MRSA bacteria. ConclusionMRSA isolates had a similarity lower than 80%, categorized in the same group. The presence of one or more virulence factors and antibiotic resistance genes amongst the resistant-MRSA bacteria signifies an important threat rendering the consumption of contaminated vegetables and salads.

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Assessing antibiotic resistance of microorganisms in sanitary sewage

Water Science & Technology ◽

10.2166/wst.2014.467 ◽

2014 ◽

Vol 71 (2) ◽

pp. 168-173 ◽

Cited By ~ 4

Author(s):

Thomas Kaeseberg ◽

Frank Blumensaat ◽

Jin Zhang ◽

Peter Krebs

Keyword(s):

Antibiotic Resistance ◽

Surface Waters ◽

Inhibitory Concentration ◽

Inhibition Test ◽

Trophic Levels ◽

Gram Negative Bacteria ◽

Clinical Tests ◽

Antimicrobial Substances ◽

Wastewater Samples ◽

Antibiotic Agents

The release of antimicrobial substances into surface waters is of growing concern due to direct toxic effects on all trophic levels and the promotion of antibiotic resistance through sub-inhibitory concentration levels. This study showcases (1) the variation of antibiotics in sanitary sewage depending on different timescales and (2) a method to assess the antibiotic resistance based on an inhibition test. The test is based on the measurement of the oxygen uptake rate (OUR) in wastewater samples with increasing concentrations of the selected antibiotic agents. The following antibiotics were analysed in the present study: clarithromycin (CLA) was selected due to its high toxicity to many microorganisms (low EC50), ciprofloxacin (CIP) which is used to generally fight all bacteria concerning interstitial infections and doxycyclin (DOX) having a broad spectrum efficacy. Results show that CLA inhibited the OUR by approximately 50% at a concentration of about 10 mg L−1, because Gram-negative bacteria such as Escherichia coli are resistant, whereas CIP inhibited about 90% of the OUR at a concentration equal to or greater than 10 mg L−1. In the case of DOX, a moderate inhibition of about 38% at a concentration of 10 mg L−1 was identified, indicating a significant antibiotic resistance. The results are consistent with the corresponding findings from the Clinical and Laboratory Standards Institute. Thus, the presented inhibition test provides a simple but robust alternative method to assess antibiotic resistance in biofilms instead of more complex clinical tests.

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