Virulence and Resistance Determinants of German Staphylococcus aureus ST398 Isolates from Nonhuman Sources

ABSTRACTA series of 100Staphylococcus aureusisolates ascribed to sequence type 398 (ST398) and recovered from different sources (healthy carrier and diseased pigs, dust from pig farms, milk, and meat) in Germany were investigated for their virulence and antimicrobial resistance genetic background. Antimicrobial resistance was determined by the disk diffusion method. Virulence and resistance determinants (37 and 31 genes, respectively) were tested by PCR. Only two virulence profiles, including the accessory gene regulatoragrIand three or four hemolysin-encoding genes, were detected. In contrast, 33 resistance profiles were distinguished (only 11 were shown by more than one isolate). Fifty-nine isolates were multiresistant (four or more antimicrobial classes), and 98 were methicillin resistant (mecApositive). All of the ST398 isolates showed resistance to tetracycline [encoded bytet(M) alone or together withtet(K) and/ortet(L)]. In addition, 98% were resistant to other antimicrobials, including macrolide-lincosamine-streptogramin B (70%, encoded byermA,ermB, andermC, alone or in combination), trimethoprim (65%, mostly due todfrKanddfrG), kanamycin and gentamicin [29% and 14%, respectively, mainly related toaac(6′)-Ie-aph(2″)-Iaand/orant(4′)-Iabut also toaph(3′)-IIIa], chloramphenicol (9%,fexAorcfr), quinupristin-dalfopristin (9%), ciprofloxacin (8%), and trimethoprim-sulfamethoxazole (4%). The heterogeneity of the resistance profiles underlines the ability of the ST398 clone to acquire multiple antimicrobial resistance genes. However, the virulence gene content of the tested isolates was low. Continuous surveillance is needed to clarify whether its pathogenicity potential for animals and humans will increase over time.

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Frequency and Characterization of Antimicrobial Resistance and Virulence Genes of Coagulase-Negative Staphylococci from Wild Birds in Spain. Detection of tst-Carrying S. sciuri Isolates

Microorganisms ◽

10.3390/microorganisms8091317 ◽

2020 ◽

Vol 8 (9) ◽

pp. 1317

Author(s):

Laura Ruiz-Ripa ◽

Paula Gómez ◽

Carla Andrea Alonso ◽

María Cruz Camacho ◽

Yolanda Ramiro ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Virulence Genes ◽

Meca Gene ◽

Virulence Gene ◽

Wild Birds ◽

Diffusion Method ◽

Coagulase Negative Staphylococci ◽

Disk Diffusion Method ◽

Resistance Phenotype ◽

Antimicrobial Resistance Genes

The objective of this study was to determine the prevalence and diversity of coagulase-negative staphylococci (CoNS) species from wild birds in Spain, as well as to analyze the antimicrobial resistance phenotype/genotype and the virulence gene content. During 2015–2016, tracheal samples of 242 wild birds were collected in different regions of Spain for staphylococci recovery. The species identification was performed using MALDI-TOF. The antimicrobial resistance phenotype and genotype was investigated by the disk diffusion method and by PCR, respectively. The presence of the virulence genes lukF/S-PV, tst, eta, etb, etd and scn was investigated by PCR. Moreover, CoNS carrying the mecA gene were subjected to SCCmec typing. Of the tested animals, 60% were CoNS-carriers, and 173 CoNS isolates were recovered from the 146 positive animals, which belonged to 11 species, with predominance of S. sciuri (n = 118) and S. lentus (n = 25). A total of 34% of CoNS isolates showed a multidrug resistance phenotype, and 42 mecA-positive methicillin-resistant CoNS (MRCoNS) were detected. The isolates showed resistance to the following antimicrobials (percentage of resistant isolates/antimicrobial resistance genes detected): penicillin (49/ blaZ, mecA), cefoxitin (24/ mecA), erythromycin and/or clindamycin (92/ erm(B), erm(C), erm(43), msr(A), mph(C), lnu(A), lsa(B), vga(A) and sal(A)), gentamicin and/or tobramycin (5/ aac(6′)-Ie-aph(2″)-Ia, ant(4′)-Ia), streptomycin (12/str), tetracycline (17/ tet(K), tet(L), tet(M)), ciprofloxacin (4), chloramphenicol (1/ fexA), fusidic acid (86/ fusB, fusD) and trimethoprim–sulfamethoxazole (1/ dfrK). None of the isolates harbored the lukF/S-PV, eta, etb, etd and scn genes, but two S. sciuri isolates (1%) carried the tst gene. Wild birds are frequently colonized by CoNS species, especially S. sciuri. We identified scavenging on intensively produced livestock and feeding on landfills as risk factors for CoNS carriage. High proportions of MRCoNS and multidrug resistant CoNS were detected, which coupled with the presence of important virulence genes is of concern.

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Culture-Independent Genotyping, Virulence and Antimicrobial Resistance Gene Identification of Staphylococcus aureus from Orthopaedic Implant-Associated Infections

Microorganisms ◽

10.3390/microorganisms9040707 ◽

2021 ◽

Vol 9 (4) ◽

pp. 707

Author(s):

J. Christopher Noone ◽

Fabienne Antunes Ferreira ◽

Hege Vangstein Aamot

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Resistance Genes ◽

Virulence Gene ◽

Orthopaedic Implant ◽

Metagenomic Sequencing ◽

Gene Detection ◽

Shotgun Metagenomic Sequencing ◽

Antimicrobial Resistance Genes ◽

Culture Independent

Our culture-independent nanopore shotgun metagenomic sequencing protocol on biopsies has the potential for same-day diagnostics of orthopaedic implant-associated infections (OIAI). As OIAI are frequently caused by Staphylococcus aureus, we included S. aureus genotyping and virulence gene detection to exploit the protocol to its fullest. The aim was to evaluate S. aureus genotyping, virulence and antimicrobial resistance genes detection using the shotgun metagenomic sequencing protocol. This proof of concept study included six patients with S. aureus-associated OIAI at Akershus University Hospital, Norway. Five tissue biopsies from each patient were divided in two: (1) conventional microbiological diagnostics and genotyping, and whole genome sequencing (WGS) of S. aureus isolates; (2) shotgun metagenomic sequencing of DNA from the biopsies. Consensus sequences were analysed using spaTyper, MLST, VirulenceFinder, and ResFinder from the Center for Genomic Epidemiology (CGE). MLST was also compared using krocus. All spa-types, one CGE and four krocus MLST results matched Sanger sequencing results. Virulence gene detection matched between WGS and shotgun metagenomic sequencing. ResFinder results corresponded to resistance phenotype. S. aureus spa-typing, and identification of virulence and antimicrobial resistance genes are possible using our shotgun metagenomics protocol. MLST requires further optimization. The protocol has potential application to other species and infection types.

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Finding of Agr Phase Variants in Staphylococcus aureus

mBio ◽

10.1128/mbio.00796-19 ◽

2019 ◽

Vol 10 (4) ◽

Cited By ~ 3

Author(s):

Vishal Gor ◽

Aya J. Takemura ◽

Masami Nishitani ◽

Masato Higashide ◽

Veronica Medrano Romero ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Virulence Factors ◽

Phase Variation ◽

Accessory Gene ◽

Content Type ◽

Accessory Gene Regulator ◽

Immune Mediated ◽

A Minor ◽

First Time ◽

Phase Variants

ABSTRACT Staphylococcus aureus is an important human pathogen whose success is largely attributed to its vast arsenal of virulence factors that facilitate its invasion into, and survival within, the human host. The expression of these virulence factors is controlled by the quorum sensing accessory gene regulator (Agr) system. However, a large proportion of clinical S. aureus isolates are consistently found to have a mutationally inactivated Agr system. These mutants have a survival advantage in the host but are considered irreversible mutants. Here we show, for the first time, that a fraction of Agr-negative mutants can revert their Agr activity. By serially passaging Agr-negative strains and screening for phenotypic reversion of hemolysis and subsequent sequencing, we identified two mutational events responsible for reversion: a genetic duplication plus inversion event and a poly(A) tract alteration. Additionally, we demonstrate that one clinical Agr-negative methicillin-resistant S. aureus (MRSA) isolate could reproducibly generate Agr-revertant colonies with a poly(A) tract genetic mechanism. We also show that these revertants activate their Agr system upon phagocytosis. We propose a model in which a minor fraction of Agr-negative S. aureus strains are phase variants that can revert their Agr activity and may act as a cryptic insurance strategy against host-mediated stress. IMPORTANCE Staphylococcus aureus is responsible for a broad range of infections. This pathogen has a vast arsenal of virulence factors at its disposal, but avirulent strains are frequently isolated as the cause of clinical infections. These isolates have a mutated agr locus and have been believed to have no evolutionary future. Here we show that a fraction of Agr-negative strains can repair their mutated agr locus with mechanisms resembling phase variation. The agr revertants sustain an Agr OFF state as long as they exist as a minority but can activate their Agr system upon phagocytosis. These revertant cells might function as a cryptic insurance strategy to survive immune-mediated host stress that arises during infection.

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Impact of agr Functionality on the Outcome of Patients with Methicillin-Susceptible Staphylococcus aureus Bacteremia

Microbiology Spectrum ◽

10.1128/spectrum.00116-21 ◽

2021 ◽

Author(s):

Jeong Eun Lee ◽

Shinwon Lee ◽

Sohee Park ◽

Soon O. Lee ◽

Sun H. Lee

Keyword(s):

Staphylococcus Aureus ◽

Accessory Gene ◽

Content Type ◽

Accessory Gene Regulator ◽

Staphylococcus Aureus Bacteremia ◽

Mssa Infection

Few studies have examined the association between methicillin-susceptible Staphylococcus aureus (MSSA) infection and accessory gene regulator ( agr ) functionality. We evaluated the association between agr dysfunction and mortality in patients with MSSA bacteremia.

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Genetic Characterization of Methicillin-Resistant Staphylococcus aureus Isolates from Human Bloodstream Infections: Detection of MLSB Resistance

Antibiotics ◽

10.3390/antibiotics9070375 ◽

2020 ◽

Vol 9 (7) ◽

pp. 375

Author(s):

Vanessa Silva ◽

Sara Hermenegildo ◽

Catarina Ferreira ◽

Célia M. Manaia ◽

Rosa Capita ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Agents ◽

Methicillin Resistant Staphylococcus Aureus ◽

Bloodstream Infections ◽

Disk Diffusion ◽

Diffusion Method ◽

Accessory Gene ◽

Spa Typing ◽

Disk Diffusion Method ◽

Methicillin Resistant

In this study we aimed to characterize antimicrobial resistance in methicillin-resistant Staphylococcus aureus (MRSA) isolated from bloodstream infections as well as the associated genetic lineages of the isolates. Sixteen MRSA isolates were recovered from bacteremia samples from inpatients between 2016 and 2019. The antimicrobial susceptibility of these isolates was tested by the Kirby–Bauer disk diffusion method against 14 antimicrobial agents. To determine the macrolide–lincosamide–streptogramin B (MLSB) resistance phenotype of the isolates, erythromycin-resistant isolates were assessed by double-disk diffusion (D-test). The resistance and virulence genes were screened by polymerase chain reaction (PCR). All isolates were characterized by multilocus sequence typing (MLST), spa typing, staphylococcal chromosomal cassette mec (SCCmec) typing, and accessory gene regulator (agr) typing. Isolates showed resistance to cefoxitin, penicillin, ciprofloxacin, erythromycin, fusidic acid, clindamycin, and aminoglycosides, confirmed by the presence of the blaZ, ermA, ermC, mphC, msrA/B, aac(6’)-Ie-aph(2’’)-Ia, and ant(4’)-Ia genes. Three isolates were Panton–Valentine-leukocidin-positive. Most strains (n = 12) presented an inducible MLSB phenotype. The isolates were ascribed to eight spa-types (t747, t002, t020, t1084, t008, t10682, t18526, and t1370) and four MLSTs (ST22, ST5, ST105, and ST8). Overall, most (n = 12) MRSA isolates had a multidrug-resistance profile with inducible MLSB phenotypes and belonged to epidemic MRSA clones.

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Methicillin-Resistant Staphylococcus aureus in Commercial Swine Herds Is Associated with Disinfectant and Zinc Usage

Applied and Environmental Microbiology ◽

10.1128/aem.00036-15 ◽

2015 ◽

Vol 81 (8) ◽

pp. 2690-2695 ◽

Cited By ~ 29

Author(s):

Mackenzie Jonathan Slifierz ◽

Robert M. Friendship ◽

J. Scott Weese

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Resistance Gene ◽

Methicillin Resistant ◽

Content Type ◽

Nursery Pigs ◽

Herd Level ◽

Antimicrobial Resistance Genes ◽

Level Information ◽

Swine Herds

ABSTRACTMethicillin-resistantStaphylococcus aureus(MRSA) originating from swine is concerning for public health, but an understanding of the emergence and persistence of MRSA in nursery herds is lacking. The aim of this study was to determine whether MRSA in nursery pigs is associated with particular herd-level parameters, including the use of antimicrobials, disinfectants, and heavy metals, which may be driving the selection and persistence of antimicrobial resistance. Nasal cultures for MRSA were completed for 390 pigs from 26 farms at the end of the suckling phase and again at 3 weeks postweaning. Herd-level information was collected, and a random subset of MRSA isolates was screened for resistance to zinc and quaternary ammonium compounds (QACs). Multivariate analysis revealed that in-feed concentrations of zinc (P< 0.001) and frequent disinfection of nursery pens (P< 0.001) are associated with MRSA shedding in nursery pigs. Furthermore, 62.5% (25/40) of MRSA isolates carried the zinc resistance geneczrCand demonstrated decreased susceptibility to zinc. All MRSA isolates carried at least 1 QAC resistance gene. The most common genotype wasqacG qacH smr, which occurred in 32.5% (13/40) of isolates. Seven isolates (17.5%) demonstrated a significant tolerance to benzalkonium chloride, indicating a potential to survive commercial QAC exposure in the presence of organic matter. Overall, these findings indicate that high levels of in-feed zinc and QAC-based disinfectants are important drivers in the selection and persistence of MRSA in commercial swine herds, and these agents may be coselecting for other antimicrobial resistance genes.

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Staphylococci among Wild European Rabbits from the Azores: A Potential Zoonotic Issue?

Journal of Food Protection ◽

10.4315/0362-028x.jfp-19-423 ◽

2020 ◽

Vol 83 (7) ◽

pp. 1110-1114 ◽

Cited By ~ 1

Author(s):

MARGARIDA SOUSA ◽

VANESSA SILVA ◽

ADRIANA SILVA ◽

NUNO SILVA ◽

JESSICA RIBEIRO ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Resistance Genes ◽

Meca Gene ◽

Diffusion Method ◽

Coagulase Negative Staphylococci ◽

Spa Typing ◽

Disk Diffusion Method ◽

Genetic Lineages ◽

Antimicrobial Resistance Genes ◽

European Rabbits

ABSTRACT The prevalence and diversity of Staphylococcus species from wild European rabbits (Oryctolagus cuniculus) in the Azores were investigated, and the antibiotic resistance phenotype and genotype of the isolates were determined. Nasal samples from 77 wild European rabbits from São Jorge and São Miguel islands in Azores were examined. Antibiotic susceptibility of the isolates was determined using the Kirby-Bauer disk diffusion method, and the presence of antimicrobial resistance genes and virulence factors was determined by PCR. The genetic lineages of S. aureus isolates were characterized by spa typing and multilocus sequence typing. A total of 49 staphylococci were obtained from 35 of the 77 wild rabbits. Both coagulase-positive (8.2%) and coagulase-negative (91.8%) staphylococci were detected: 4 S. aureus, 17 S. fleurettii, 13 S. sciuri, 7 S. xylosus, 4 S. epidermidis, and 1 each of S. simulans, S. saprophyticus, S. succinus, and S. equorum. The four S. aureus isolates showed methicillin susceptibility and were characterized as spa type t272/CC121, Panton-Valentine leukocidin negative, and hlB positive. Most of the coagulase-negative staphylococci showed resistance to fusidic acid and beta-lactams, and multidrug resistance was identified especially among S. epidermidis isolates. The mecA gene was detected in 20 isolates of the species S. fleurettii and S. epidermidis, associated with the blaZ gene in one S. epidermidis isolate. Five antimicrobial resistance genes were detected in one S. epidermidis isolate (mecA,dfrA,dfrG,aac6′-aph2′′, and ant4). Our results highlight that wild rabbits are reservoirs or “temporary hosts” of Staphylococcus species with zoonotic potential, some of them carrying relevant antimicrobial resistances. HIGHLIGHTS

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Staphylococcus aureus CodY Negatively Regulates Virulence Gene Expression

Journal of Bacteriology ◽

10.1128/jb.01545-07 ◽

2007 ◽

Vol 190 (7) ◽

pp. 2257-2265 ◽

Cited By ~ 120

Author(s):

Charlotte D. Majerczyk ◽

Marat R. Sadykov ◽

Thanh T. Luong ◽

Chia Lee ◽

Greg A. Somerville ◽

...

Keyword(s):

Gene Expression ◽

Staphylococcus Aureus ◽

Regulatory Protein ◽

Virulence Gene ◽

Culture Fluid ◽

Accessory Gene ◽

Virulence Gene Expression ◽

Gram Positive Bacteria ◽

Accessory Gene Regulator ◽

Branched Chain

ABSTRACT CodY is a global regulatory protein that was first discovered in Bacillus subtilis, where it couples gene expression to changes in the pools of critical metabolites through its activation by GTP and branched-chain amino acids. Homologs of CodY can be found encoded in the genomes of nearly all low-G+C gram-positive bacteria, including Staphylococcus aureus. The introduction of a codY-null mutation into two S. aureus clinical isolates, SA564 and UAMS-1, through allelic replacement, resulted in the overexpression of several virulence genes. The mutant strains had higher levels of hemolytic activity toward rabbit erythrocytes in their culture fluid, produced more polysaccharide intercellular adhesin (PIA), and formed more robust biofilms than did their isogenic parent strains. These phenotypes were associated with derepressed levels of RNA for the hemolytic alpha-toxin (hla), the accessory gene regulator (agr) (RNAII and RNAIII/hld), and the operon responsible for the production of PIA (icaADBC). These data suggest that CodY represses, either directly or indirectly, the synthesis of a number of virulence factors of S. aureus.

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Antimicrobial Resistance and Virulence Determination of Enterococcus spp. Obtained from Hospital Environment in Iran

10.21203/rs.3.rs-123398/v1 ◽

2020 ◽

Author(s):

Saba Asgharzadeh Marghmalek ◽

Reza Valadan ◽

Mehrdad Gholami ◽

Mohtaram Nasrolahei ◽

Hamid Reza Goli

Keyword(s):

Antimicrobial Resistance ◽

Resistance Genes ◽

Pathogenic Bacteria ◽

Antibiotic Resistance Genes ◽

Hospital Environment ◽

Diffusion Method ◽

Virulence Determinants ◽

Environmental Isolates ◽

Disk Diffusion Method ◽

Antimicrobial Resistance Genes

Abstract Background: The role of the hospital environment as a source of pathogenic bacteria in recent studies has been poorly investigated. This study investigated the distribution of antimicrobial resistance genes and virulence determinants in Enterococcus species isolated from hospital environment in Sari, Iran. Method: Overall, 90 enterococci strains were obtained from high touch surfaces of four hospitals in Sari, Iran. These environmental samples were obtained from bathroom, beds, tables, doorknobs, room keys, wheelchair and walls in the patient and staff’s rooms. The resistance profile of the isolates was determined by disk diffusion method. Seven resistance genes and two virulence associated genes were evaluated molecularly by multiplex PCR. Results: According to the PCR, 42 (46.66%) of them were E. faecalis and 48 (53.33%) others were detected as E. faecium. Also, 28 (66.6%) E. faecalis and 18 (37.5%) E. faecium isolates were multidrug-resistant (MDR). Among all 90 environmental isolates 54 (60%), 54 (60%), 8 (8.8%), 8 (8.8%), 60 (66.6%), 26 (28.8%), and 24 (26.6%) isolates contained tetM, tetL, vanA, vanB, ermB, aac(6´)-Ie-aph(2´´)-Ia, and aph (3´)-IIIa, respectively. Moreover, all isolates were investigated for the presence of virulence genes and 88 (97.7%) of isolates had esp gene, and 16 (17.7%) had ace.Conclusions: This report showed that the environmental isolates of Enterococcus are the major sources of antibiotic resistance genes that can transfer them to the clinical isolates of bacteria in hospital settings. An effective following strategy should be organized to clearance and stop emergence of these pathogenic bacteria.

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Antimicrobial Resistance Profile of Salmonella and Listeria monocytogenes Isolated from Products Marketed on the Border of Brazil with Argentina and Uruguay

Journal of Food Protection ◽

10.4315/jfp-20-176 ◽

2020 ◽

Vol 83 (11) ◽

pp. 1941-1946

Author(s):

JULIANO GONÇALVES PEREIRA ◽

VANESSA MENDONÇA SOARES ◽

LEONARDO ERENO TADIELO ◽

TASSIANA RAMIRES ◽

WLADIMIR PADILHA da SILVA

Keyword(s):

Listeria Monocytogenes ◽

Antimicrobial Resistance ◽

Foodborne Pathogens ◽

Penicillin G ◽

Diffusion Method ◽

Salmonella Spp ◽

Disk Diffusion Method ◽

Resistance Profile ◽

Antimicrobial Resistance Profile ◽

Antimicrobial Resistance Genes

ABSTRACT We aimed to perform serotyping and the antimicrobial resistance profile of Salmonella spp. and Listeria monocytogenes strains isolated from raw meats imported illegally into Brazil along the borders of Argentina and Uruguay. Distinct isolates of Salmonella spp. (n = 6) and L. monocytogenes (n = 25) obtained from 270 of these food products of earlier work were serotyped and tested for antimicrobial resistance by agar disk diffusion method. For strains that were considered phenotypically resistant, antimicrobial resistance genes were investigated: strA, strB, floR, tetA, tetB, blaZ, blaTEM, ermB, ermC, and ereB to Salmonella sp. and blaZ and mecA to L. monocytogenes. All Salmonella isolates were identified as Salmonella Infantis; they were multidrug resistant and harbored the genes blaTEM (n = 6), strA (n = 1), strB (n = 1), floR (n = 1), ermB (n = 1), tetA (n = 3), and tetB (n = 3). L. monocytogenes isolates belonged to serovars 1/2a (n = 1), 1/2b (n = 14), 1/2c (n = 2), and 4b (n = 8), showed resistance only to penicillin G (n = 12), and did not show the blaZ and mecA genes. The results demonstrated that illegal foods that are commercialized in the Brazilian international border with Argentina and Uruguay may harbor foodborne pathogens, and some of them have multidrug resistance characteristics, such as Salmonella, emphasizing the need for greater control of international food transit in Brazil, especially in the region evaluated. HIGHLIGHTS

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