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

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Xuehan Li ◽  
Tao Huang ◽  
Kai Xu ◽  
Chenglin Li ◽  
Yirong Li

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.

2019 ◽  
Author(s):  
Xuehan Li ◽  
Tao Huang ◽  
Kai Xu ◽  
Chenglin Li ◽  
Yirong Li

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: 227 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 2013-2014 (5.5%, 5/91) to 2018-2019 (18.4%, 25/136). Seventy-six MRSA isolates were subject to staphylococcus chromosomal cassette mec (SCC mec ) typing. SCC mec- IVa was the predominant SCC mec type, and specifically, ST45-SCC mec 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.


2019 ◽  
Author(s):  
Xuehan Li ◽  
Tao Huang ◽  
Kai Xu ◽  
Chenglin Li ◽  
Yirong Li

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: 227 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 2013-2014 (5.5%, 5/91) to 2018-2019 (18.4%, 25/136). Seventy-six MRSA isolates were subject to staphylococcus chromosomal cassette mec (SCC mec ) typing. SCC mec- IVa was the predominant SCC mec type, and specifically, ST45-SCC mec 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.


2019 ◽  
Author(s):  
Xuehan Li ◽  
Tao Huang ◽  
Kai Xu ◽  
Chenglin Li ◽  
Yirong Li

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: 227 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 2013-2014 (5.5%, 5/91) to 2018-2019 (18.4%, 25/136). Seventy-six MRSA isolates were subject to staphylococcus chromosomal cassette mec (SCC mec ) typing. SCC mec- IVa was the predominant SCC mec type, and specifically, ST45-SCC mec 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.


2019 ◽  
Author(s):  
Xuehan Li ◽  
Kai Xu ◽  
Chenglin Li ◽  
Tao Huang ◽  
Yirong Li

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: 227 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, and antibiotic resistance profiles. Results: Thirty-four sequence types (STs) and 79 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 moreover, the prevalence of ST398-MSSA increased significantly from 2013-2014 (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. Eleven virulence genes, including the Panton-Valentine leukocidin (pvl) and eta, were determined, and the positive rates of eta and pvl were found to be 57.3% and 47.6%. Such high prevalence has never been seen in mainland China before.


2020 ◽  
Author(s):  
Raymond Mudzana ◽  
Rooyen T Mavenyengwa ◽  
Muchaneta Gudza-Mugabe

Abstract Background: Streptococcus agalacticae is one of the most important causative agents of serious infections among neonates. Group B Streptococcus (GBS) virulence factors are important in the development of vaccines, whilst antibiotic resistance genes are necessary in understanding the resistance mechanisms used by these pathogens. This study was carried out to identify the virulence genes and antibiotic resistance genes associated with GBS isolated from pregnant women.Methods: A total of 43 GBS isolates were obtained from vaginal samples that were collected from all HIV positive and HIV negative women who were 13-35 weeks pregnant attending Antenatal Care at both Chitungwiza and Harare Central Hospitals in Zimbabwe. Identification tests of GBS isolates was done using standard bacteriological methods including molecular tests. Antibiotic susceptibility testing using 3 antibiotics was done using the modified Kirby-Bauer method. The boiling method was used to extract DNA and Polymerase Chain Reaction (PCR) was used to screen for 13 genes in the isolates. Data was fed into SPSS 24.0 and the Spearman rank correlation test used to determine any correlation among genes.Results: Nine distinct virulence gene profiles were identified. The profiles hly-scpB-bca-rib 37.2% (16/43) and hly-scpB-bca 18.6% (8/43) were common among GBS isolates. The following virulence gene frequencies were obtained namely hly 97.8% (42/43), scpB 90.1% (39/43), bca 86.0% (37/43), rib 69.8% (30/43) and bac 11.6% (5/43). Antibiotic resistance genes showed high frequencies for tetM 97.6% (41/42) and low frequencies for ermB 34.5% (10/29), ermTR 10.3% (3/29), mefA 3.4% (1/29), tetO 2.4% (1/42) and linB 0% (0/35). The atr housekeeping gene amplification yielded 100% (43/43) positive results, whilst the mobile genetic element IS1548 yielded a low 9.3% (4/43).Conclusion: The study showed a high prevalence of multiple virulence genes hly, scpB, bca and rib in S. agalactiae strains isolated from pregnant women. Tetracycline resistance was found to be predominantly caused by the tetM gene, whilst macrolide resistance was predominantly due to the presence of erm methylase, with the ermB gene being more prevalent. It was also observed that in vitro phenotypic resistance is not always accurately predicted by resistance genotypes.


2020 ◽  
Author(s):  
Raymond Mudzana ◽  
Rooyen T Mavenyengwa ◽  
Muchaneta Gudza-Mugabe

Abstract Background : Streptococcus agalacticae (Group B Streptococcus, GBS) is one of the most important causative agents of serious infections among neonates. GBS virulence factors are important in vaccine development, whilst antibiotic resistance genes are necessary in understanding the resistance mechanisms used by pathogens. This study was carried out to identify virulence genes and antibiotic resistance genes associated with GBS isolated from pregnant women. Methods: A total of 43 GBS isolates were obtained from 420 vaginal samples collected from HIV positive and negative women who were 13-35 weeks pregnant attending Antenatal Care at Chitungwiza and Harare Central Hospitals in Zimbabwe. Identification tests of GBS isolates was done using standard bacteriological methods including molecular tests. Antibiotic susceptibility testing using 3 antibiotics was done using the modified Kirby-Bauer method. The boiling method was used to extract DNA and Polymerase Chain Reaction (PCR) was used to screen for 13 genes. Data was fed into SPSS 24.0 and the Spearman rank correlation test used to determine correlation among genes. Results: Nine distinct virulence gene profiles were identified. The profiles hly-scpB-bca-rib 37.2% (16/43) and hly-scpB-bca 18.6% (8/43) were common. The following virulence gene frequencies were obtained namely hly 97.8% (42/43), scpB 90.1% (39/43), bca 86.0% (37/43), rib 69.8% (30/43) and bac 11.6% (5/43). High resistance to tetracycline 97.7% (42/43) was reported followed by clindamycin 55.8% (24/43) and erythromycin 30.2% (13/43). Antibiotic resistance genes among the resistant and intermediate-resistant isolates showed high frequencies for tetM 97.6% (41/42) and low frequencies for ermB 34.5% (10/29), ermTR 10.3% (3/29), mefA 3.4% (1/29), tetO 2.4% (1/42) and linB 0% (0/35). The atr housekeeping gene yielded 100% (43/43) positive results, whilst the mobile genetic element IS1548 yielded 9.3% (4/43). Conclusion: The study showed high prevalence of multiple virulence genes hly, scpB, bca and rib in S. agalactiae strains isolated from pregnant women. Tetracycline resistance was found to be predominantly caused by the tetM gene, whilst macrolide resistance was predominantly due to the presence of erm methylase, with the ermB gene being more prevalent. It was also observed that in vitro phenotypic resistance is not always accurately predicted by resistance genotypes.


2020 ◽  
Author(s):  
Adebayo O. Shittu ◽  
Tomiwa Adesoji ◽  
Edet E. Udo

AbstractStaphylococcus aureus is an important human pathogen with an arsenal of virulence factors and a propensity to acquire antibiotic resistance genes. The understanding of the global epidemiology of S. aureus through the use of various typing methods is important in the detection and tracking of novel and epidemic clones in countries and regions. However, detailed information on antibiotic resistance and virulence genes of S. aureus, and its population structure is still limited in Africa. In this study, S. aureus isolates collected in South Africa (n=38) and Nigeria (n=2) from 2001-2004 were characterized using DNA microarray. The combination of spa typing and DNA microarray classified the isolates into seven spa types and three clonal complexes (CCs) i.e. t064-CC8 (n=17), t037-CC8 (n=8), t1257-CC8 (n=6), t045-CC5 (n=5), t951-CC8 (n=1), t2723-CC88 (n=1), t6238-CC8 (n=1), and untypeable-CC8 (n=1). There was excellent agreement (only two discordant results) between antibiotic susceptibility testing and the detection of the corresponding resistance genes by DNA microarray. Antibiotic and virulence gene markers were associated with specific clones. The detection of the collagen-binding adhesion (cna) gene was unique for t037-CC8-MRSA, the enterotoxin gene cluster (egc) and staphylococcal complement inhibitor (scn) gene for t045-CC5-MRSA, and the combination of genes encoding enterotoxin (entA, entB, entK, entQ) were noted with most of the CC8 isolates. The t045-CC5-MRSA clone was positive for the mercury resistance (mer) operon. DNA microarray assay provides information on antibiotic resistance and virulence gene determinants and can be a useful tool to identify gene markers of specific S. aureus clones in Africa.


2020 ◽  
Author(s):  
Nazanin Fazel ◽  
Sepideh Karimi ◽  
Hassan Momtaz

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.


2019 ◽  
Vol 22 (4) ◽  
pp. 419-427
Author(s):  
S. Nouri Gharajalar ◽  
M. Onsori

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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