2602. Genetic Basis of Staphylococcus aureus Virulence

Abstract Background Although multiple different virulence factors have been identified for Staphylococcus aureus, there is limited information on genetic variation present between different strains of S. aureus in the clinical setting. To better define whether differing virulence factors could contribute to differing clinical manifestations of S. aureus infections we undertook a comparison of the frequency of virulence and antibiotic resistance genes present in S. aureus isolates from different clinical sites. Methods Whole-genome sequencing was performed on a convenience sample of S. aureus isolates from clinical or surveillance cultures obtained at an academic medical center over a 27-month period. Genomic assemblies were generated and annotated to define protein-coding regions. The prevalence of 28 genes previously defined as being associated with S. aureus virulence or antimicrobial resistance, including MSCRAMM genes, was then analyzed in relation to nine specific culture sources including only a single isolate from each culture source per patient using a likelihood ratio χ 2 analysis. Results There were 1286 S. aureus isolates with draft assemblies and annotations, and there was a statistically significant (P < 0.01) difference in gene frequencies between culture sources for 18 genes that included 13 of 19 virulence factors, 4 of 7 antibiotic resistance genes and 1 of 2 MSCRAMM genes. The most notable variation was seen for the presence of the sec, sep, entB, lukS, lufK, fosB, mecA, and ermA genes (all with P < 0.0001). There were also significant variations in overall gene frequency patterns between isolates from wound, blood, and respiratory isolates (P < 0.0001), as well as significant differences in the frequency of cna and hlY genes between surveillance and clinical isolates (P < 0.0001). Conclusion This study demonstrates a difference in the prevalence of virulence and antibiotic resistance genes in S. aureus isolates based on the culture source. As the culture location can be considered a surrogate for different types of infections (such as bacteremia, pneumonia, urinary tract infections) these differences in gene frequency may contribute to variation in the clinical manifestations of infections by differing S. aureus strains. Disclosures All authors: No reported disclosures.

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Urinary Tract Infections in Benin: Exploring the Virulence Factors and Antibiotic Resistance and Virulence Genes among Bacterial Isolates

International Journal of Pathogen Research ◽

10.9734/ijpr/2021/v7i130174 ◽

2021 ◽

pp. 28-36

Author(s):

Victorien Dougnon ◽

Phénix Assogba ◽

Jibril Mohammed ◽

Jerrold Agbankpe ◽

Esther Deguenon ◽

...

Keyword(s):

Antibiotic Resistance ◽

Urinary Tract ◽

Virulence Factors ◽

Urinary Tract Infections ◽

Resistance Genes ◽

Antibiotic Resistance Genes ◽

Public Health Problem ◽

Virulence Gene ◽

Scientific Data ◽

Tract Infections

Objective: The emergence and increasing spread of resistance to antibiotics in uropathogenic Enterobacteriaceae is a huge public health problem and increase the morbidity and mortality. The objective of this study was to produce scientific data on the virulence and level of resistance of these bacteria in Benin. Results: This study was conducted on 230 strains of enterobacteria isolated from patients with urinary tract infections. These virulence factors sought were hemolysis, hemagglutination, serum resistance, biofilm formation, and the production of lipase, protease and lecithinase. The molecular characterization of the virulence and antibiotic resistance genes was accomplished by PCR according to the different conditions for each gene. The bacteria possessed several types of virulence factors such as hemagglutinin (28.26%), lipase production (23.92%) and hemolysin production (17.83%). The virulence gene identified were FimH (74.79%), PapC (30.44%), Iss (11.34%) and Biofilm (3.92%). The antibiotic resistance genes such as Bla-SHV (49.56%), Bla-CTX-M15, Bla-CTX-M2 (33.92%), Bla-CTX-M9 (19.13%) and bla-CTX-M1 (11.74%) were also detected. Conclusion: These results filled the national gap about virulence and antimicrobial resistance of enterobacteria responsible of urinary tract infection and may be used to improve the management of patients in Benin.

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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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Molecular typing, phenotypic and genotypic assessment of antibiotic resistance and virulence factors amongst the Staphylococcus aureus bacteria isolated from raw chicken meat

10.21203/rs.3.rs-21570/v1 ◽

2020 ◽

Author(s):

Nazanin Fazel ◽

Sepideh Karimi ◽

Hassan Momtaz

Keyword(s):

Staphylococcus Aureus ◽

Antibiotic Resistance ◽

Virulence Factors ◽

Resistance Genes ◽

Molecular Typing ◽

Virulence Genes ◽

Antibiotic Resistance Genes ◽

Chicken Meat ◽

Genetic Cluster ◽

Meat Samples

Abstract Background: Staphylococcus aureus is an important cause of foodborne diseases due to the consumption of contaminated raw chicken meat. The present research was performed to evaluate the phenotypic and genotypic properties of antibiotic resistance, virulence factor profiles and molecular typing of S. aureus strains isolated from chicken meat. A total of 36 S. aureus strains were isolated from raw chicken meat samples. Phenotypic pattern of antibiotic resistance was assessed by disk diffusion. Distribution of antibiotic resistance and virulence genes was evaluated by PCR. Molecular typing of isolates was perform ed by the ERIC-PCR. Results: Considering the over than 80% similarity, 36 S. aureus isolates were classified in 9 different profiles with 43 to 100% similarities. S. aureus strains showed the highest incidence of resistance against penicillin (100%), tetracycline (91.66%), cephalothin (77.77%), ciprofloxacin (75%), erythromycin (75%), mupirocin (63.88%), clindamycin (61.11%) and trimethoprim/sulfamethoxazole (61.11%). The most commonly detected antibiotic resistance genes amid the S. aureus isolates were mecA (100%), tetK (80.55%), tetM (66.66%), aacA-D (61.11%), msrA (55.55%) and ermA (55.55%). Total distribution of etB, etA, tsst-1, clfA and coa virulence factors amongst the S. aureus strains was 61.11%, 58.33%, 13.88%, 75% and 100%, respectively. Conclusions: Genetic cluster of bacteria affected the antibiotic resistance and virulence characters of S. aureus strains. S. aureus strains with the same ERIC-genetic cluster had similar antibiotic resistance and virulence characters which may show their similar origins. Presence of one or more virulence factors and antibiotic resistance genes amongst the resistant-S. aureus strains signifies an important public health threat rendering the consumption of raw or undercooked chicken meat.

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Virulence Factors in Coagulase-Negative Staphylococci

Pathogens ◽

10.3390/pathogens10020170 ◽

2021 ◽

Vol 10 (2) ◽

pp. 170

Author(s):

Angela França ◽

Vânia Gaio ◽

Nathalie Lopes ◽

Luís D. R. Melo

Keyword(s):

Antibiotic Resistance ◽

Virulence Factors ◽

Resistance Genes ◽

Biofilm Formation ◽

Antibiotic Resistance Genes ◽

Coagulase Negative Staphylococci ◽

Healthcare Associated ◽

Major Pathogens

Coagulase-negative staphylococci (CoNS) have emerged as major pathogens in healthcare-associated facilities, being S. epidermidis, S. haemolyticus and, more recently, S. lugdunensis, the most clinically relevant species. Despite being less virulent than the well-studied pathogen S. aureus, the number of CoNS strains sequenced is constantly increasing and, with that, the number of virulence factors identified in those strains. In this regard, biofilm formation is considered the most important. Besides virulence factors, the presence of several antibiotic-resistance genes identified in CoNS is worrisome and makes treatment very challenging. In this review, we analyzed the different aspects involved in CoNS virulence and their impact on health and food.

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Molecular characteristics and virulence gene profiles of Staphylococcus aureus isolates in Hainan, China

BMC Infectious Diseases ◽

10.1186/s12879-019-4547-5 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 8

Author(s):

Xuehan Li ◽

Tao Huang ◽

Kai Xu ◽

Chenglin Li ◽

Yirong Li

Keyword(s):

Staphylococcus Aureus ◽

Antibiotic Resistance ◽

Resistance Genes ◽

Virulence Genes ◽

Mainland China ◽

Geographical Location ◽

Antibiotic Resistance Genes ◽

Virulence Gene ◽

Molecular Characteristics ◽

Staphylococcal Protein A

Abstract Background There have been no reports regarding the molecular characteristics, virulence features, and antibiotic resistance profiles of Staphylococcus aureus (S. aureus) from Hainan, the southernmost province of China. Methods Two hundred twenty-seven S. aureus isolates, consisting of 76 methicillin-resistant S. aureus (MRSA) and 151 methicillin-susceptible S. aureus (MSSA), were collected in 2013–2014 and 2018–2019 in Hainan, and investigated for their molecular characteristics, virulence genes, antibiotic resistance profiles and main antibiotic resistance genes. Results Forty sequence types (STs) including three new STs (ST5489, ST5492 and ST5493), and 79 Staphylococcal protein A (spa) types were identified based on multilocus sequence typing (MLST) and spa typing, respectively. ST398 (14.1%, 32/227) was found to be the most prevalent, and the prevalence of ST398-MSSA increased significantly from 2013 to 2014 (5.5%, 5/91) to 2018–2019 (18.4%, 25/136). Seventy-six MRSA isolates were subject to staphylococcus chromosomal cassette mec (SCCmec) typing. SCCmec-IVa was the predominant SCCmec type, and specifically, ST45-SCCmec IVa, an infrequent type in mainland China, was predominant in S. aureus from Hainan. The antibiotic resistance profiles and antibiotic resistance genes of S. aureus show distinctive features in Hainan. The resistant rates of the MRSA isolates to a variety of antibiotics were significantly higher than those of the MSSA isolates. The predominant erythromycin and tetracycline resistance genes were ermC (90.1%, 100/111) and tetK (91.8%, 78/85), respectively. Eleven virulence genes, including the Panton-Valentine leukocidin (pvl) and eta, were determined, and the frequency of eta and pvl were found to be 57.3 and 47.6%. Such high prevalence has never been seen in mainland China before. Conclusion S. aureus isolates in Hainan have unique molecular characteristics, virulence gene and antibiotic resistance profiles, and main antibiotic resistance genes which may be associated with the special geographical location of Hainan and local trends in antibiotic use.

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Molecular detection of antibiotic resistance genes in multidrug-resistant Staphylococcus aureus isolates from dog dental plaque

BULGARIAN JOURNAL OF VETERINARY MEDICINE ◽

10.15547/bjvm.2099 ◽

2019 ◽

Vol 22 (4) ◽

pp. 419-427

Author(s):

S. Nouri Gharajalar ◽

M. Onsori

Keyword(s):

Staphylococcus Aureus ◽

Antibiotic Resistance ◽

Multiplex Pcr ◽

Resistance Genes ◽

Dental Plaque ◽

Antibiotic Resistance Genes ◽

Multidrug Resistant ◽

Diffusion Method ◽

Pcr Assay ◽

Multiplex Pcr Assay

Multidrug resistant Staphylococcus aureus strains are a major health care problem both in humans and animals. In this work we described three multiplex PCR assays for detection of clinically relevant antibiotic resistance genes in S. aureus isolated from dog dental plaques. Thirty dental plaque samples were collected; then cultural, biochemical and molecular tests performed for isolation and identification of S. aureus from samples. The antibiotic susceptibility of the isolates were checked by Kirby Bauer disc diffusion method and the prevalence of antibiotic resistance genes determined using multiplex PCR assay. As a result S. aureus was isolated from 18 dog plaque samples. Fifteen of these isolates were resistant to penicillin. The mecA gene was more prevalent than blaZ among penicillin-resistant bacteria. Ten of the isolates were resistant to tetracycline. The percentage of tetM was higher than tetK among them. Also, 10 of the isolates were resistant to cefazolin among them bla TEM detected in higher rate than blaSHV and blaOXA-1. Hence multiplex PCR assay is a suitable method for detection of antibiotic resistance patterns of S. aureus isolates.

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