scholarly journals The effect of type II toxin-antitoxin systems on methicillinresistant Staphylococcus aureus persister cell formation and antibiotic tolerance

2021 ◽  
Vol 65 (1) ◽  
pp. 113-117
Author(s):  
Mandana Hosseini ◽  
Jamileh Nowroozi ◽  
Nour Amirmozafari
Keyword(s):  
Staphylococcus Aureus ◽  
Potential Role ◽  
Cell Formation ◽  
Antibiotic Tolerance ◽  
Type Ii ◽  
Persister Cells ◽  
Methicillin Resistant ◽  
Pcr Method ◽  
Persister Cell ◽  
Lethal Doses

Persister cells are defi ned as a subpopulation of bacteria in a dormant state with the ability to reduce bacterial metabolism and they are involved in antibiotic tolerance. Toxin-antitoxin (TA) systems have been previously suggested as important players in persistence. Therefore, this study aimed to study the involvement of TA systems in persister cell formation in methicillin-resistant Staphylococcus aureus following antibiotic exposure. Using TADB and RASTA database, two type II TA systems including MazF/MazE and RelE/RelB were predicted in S. aureus. The presence of these TA genes was determined in 5 methicillin-resistant S. aureus isolates and the standard strain S. aureus subsp. aureus N315 using PCR method. To induce persistence, isolates were exposed to lethal doses of ciprofl oxacin and the expression of the studied TA system genes was measured after 5 h using Real-Time PCR. According to our results, all the studied isolates harbored the TA system genes. S. aureus was highly capable of persister cell formation following exposure to sub-MIC of ciprofl oxacin and RT-qPCR showed a signifi cant increase in the expression of the MazEF and RelBE loci, indicating their potential role in antibiotic tolerance. Considering the importance of antibiotic tolerance, further studies on persister cell formation and TA systems involved in this phenomenon are required to effi ciently target these systems.

Biofilm Persister Cell Formation, and Relative Gene Expression Analysis of Type II Toxin-Antitoxin System in Pseudomonas Aeruginosa Strains in the Exponential and Stationary Phases

2021 ◽  
Author(s):  
Rezvan Golmoradi Zadeh ◽  
Behrooz Sadeghi Kalani ◽  
Marzie Mahdizade Ari ◽  
Malihe Talebi ◽  
Shabnam Razavi ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Real Time ◽  
Bacterial Growth ◽  
Real Time Pcr ◽  
Stationary Phases ◽  
Cell Formation ◽  
Type Ii ◽  
Persister Cells ◽  
Persistent Infections ◽  
Persister Cell

Abstract Chronic and persistent infections and therapy failure are concerning issues in patients with Pseudomonas aeruginosa infections. Presence of persister cells in biofilm considers as one from the causes for antibiotic resistance and treatment failure. Consequently, in this research, the expression of TA type II systems into persister formation of biofilm was assessed in presence of colistin ciprofloxacin antibiotics into exponential and stationary phases. The results showed that TA systems at different stages of bacterial growth in biofilm have different functions that subsequently, cause differences in the presence amount of persister cells at each stage of bacterial growth. The expression of the systems were measured by Real-Time PCR method. Keywords: Persister cell; Biofilm; Pseudomonas aeruginosa; TA systems; Real-time PCR; Exponential and Stationary phases

scholarly journals Role of Global Regulators and Nucleotide Metabolism in Antibiotic Tolerance in Escherichia coli

2008 ◽  
Vol 52 (8) ◽  
pp. 2718-2726 ◽  
Author(s):  
Sonja Hansen ◽  
Kim Lewis ◽  
Marin Vulić
Keyword(s):  
Escherichia Coli ◽  
Cell Formation ◽  
Nucleotide Metabolism ◽  
Flavin Mononucleotide ◽  
Formation Mechanisms ◽  
Antibiotic Tolerance ◽  
Persister Cells ◽  
Global Regulators ◽  
Persister Cell

ABSTRACT Bacterial populations produce a small number of persister cells that exhibit multidrug tolerance. Persister cells are largely responsible for the antibiotic recalcitrance of biofilm infections. The mechanism of persister cell formation largely remains unknown due to the challenges in identifying persister genes. We screened an ordered comprehensive library of 3,985 Escherichia coli knockout strains to identify mutants with altered antibiotic tolerance. Stationary-state cultures in 96-well plates were exposed to ofloxacin at a concentration which allows only tolerant persister cells to survive. The persister cell level of each culture was determined. A total of 150 mutants with decreased persistence were identified in the initial screen, and subsequent validation confirmed that neither the growth rate nor the ofloxacin MIC was affected for 10 of them. The genes affected in these strains were dnaJ and dnaK (chaperones), apaH (diadenosine tetraphosphatase), surA (peptidyl-prolyl cis-trans isomerase), fis and hns (global regulators), hnr (response regulator of RpoS), dksA (transcriptional regulator of rRNA transcription), ygfA (5-formyl-tetrahydrofolate cyclo-ligase), and yigB (flavin mononucleotide [FMN] phosphatase). The prominent presence of global regulators among these strains pointed to the likely redundancy of persister cell formation mechanisms: the elimination of a regulator controlling several redundant persister genes would be expected to produce a phenotype. This observation is consistent with previous findings for a possible role of redundant genes such as toxin/antitoxin modules in persister cell formation. ygfA and yigB were of special interest. The mammalian homolog of YgfA (methenyltetrahydrofolate synthetase) catalyzes the conversion of 5-formyl-tetrahydrofolate (THF) into the rapidly degraded 5,10-methenyl-THF, depleting the folate pool. The YigB protein is a phosphatase of FMN which would deplete the pool of this cofactor. Stochastic overexpression of these genes could lead to dormancy and, hence, tolerance by depleting the folate and FMN pools, respectively. Consistent with this scenario, the overexpression of both genes produced increased tolerance to ofloxacin.

scholarly journals The Expression of Type II TA System Genes Following Persister Cell Formation in Pseudomonas Aeruginosa Isolates in The Exponential and Stationary Phases

2021 ◽  
Author(s):  
Rezvan Golmorazi Zadeh ◽  
Maryam Mirshekar ◽  
Behrouz Sadeghi Kalani ◽  
Faramarz Masjedian ◽  
Mahmood Barati
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phases ◽  
Cell Formation ◽  
Exponential Phase ◽  
Type Ii ◽  
Persister Cells ◽  
Time Intervals ◽  
Qrt Pcr ◽  
Colony Counting ◽  
Persister Cell

Abstract Objectives: Failure of infection therapy in the presence of antibiotics has become a major problem which has been mostly attributed to the ability of bacterial persister cell formation. Bacteria use various mechanisms to form persister cells in different phases, among which is the toxin-antitoxin (TA) systems. This study aimed at investigating the expression of type II TA system genes under the stress of ciprofloxacin and colistin antibiotics in the exponential and stationary phases.Methods: To determine the effects of ciprofloxacin and colistin on persister cell formation in the exponential and stationary phases of Pseudomonas aeruginosa strains, colony counting was performed at different time intervals in the presence of 5-fold MIC of ciprofloxacin and colistin. In addition, the expression of relBE, Xre-COG5654, vapBC, and Xre-GNAT genes in P. aeruginosa isolates was assessed 3.5 h after antibiotic treatment in the exponential and stationary phases using qRT-PCR.Results: Our results indicated the presence of persister phenotype of P. aeruginosa strains in the presence of 5-fold MIC of ciprofloxacin and colistin compared to the control after 3.5 h of incubation in the exponential and stationary phases. Also, the number of persister cells in the stationary phase was higher than that of the exponential phase. According to the results of qRT-PCR, ciprofloxacin and colistin may induce persister cells by increasing the expression of type II TA systems in stationary and exponential phases.Conclusion: Ciprofloxacin and colistin may increase the formation of persister cells by affecting the expression of type II TA systems.

RNA antitoxin SprF1 binds ribosomes to attenuate translation and promote persister cell formation in Staphylococcus aureus

2021 ◽  
Author(s):  
Marie-Laure Pinel-Marie ◽  
Régine Brielle ◽  
Camille Riffaud ◽  
Noëlla Germain-Amiot ◽  
Norbert Polacek ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Formation ◽  
Persister Cell

scholarly journals Inactivation of TCA cycle enhances Staphylococcus aureus persister cell formation in stationary phase

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Ying Wang ◽  
Martin Saxtorph Bojer ◽  
Shilpa Elizabeth George ◽  
Zhihao Wang ◽  
Peter Ruhdal Jensen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Stationary Phase ◽  
Cell Formation ◽  
Tca Cycle ◽  
Persister Cell

scholarly journals Distribution of Virulence Genes Among Methicillin-resistant Staphylococcus Aureus of Clinical and Environmental Origin

2020 ◽  
Author(s):  
Deepshikha Bhowmik ◽  
Shiela Chetri ◽  
Bhaskar Jyoti Das ◽  
Debadatta Dhar Chanda ◽  
Amitabha Bhattacharjee
Keyword(s):  
Staphylococcus Aureus ◽  
Multidrug Resistance ◽  
Virulence Genes ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Virulence Gene ◽  
Type I ◽  
Type Ii ◽  
Methicillin Resistant ◽  
Type Iv ◽  
Type V

Abstract Objective: This study was designed to discover the dissemination of virulence genes in Methicillin-resistant Staphylococcus aureus from clinical and environmental settings. Results: The virulence gene such as sea (n=54), seb (n=21), eta (n=27), etb (n=2), cna (n=24), ica (n=2) and tst (n=30) was revealed from this study. Different SCCmec types such as type I, type II, type III, type IV, type V, type VI, type VII, type VIII and type XII were detected among sixty three MRSA isolates where SCCmec type II having ST1551 and type V with ST2416 were found to be associated with multidrug resistance and were highly prevalent in the study area.

scholarly journals A selective membrane-targeting repurposed antibiotic with activity against persistent methicillin-resistant Staphylococcus aureus

2019 ◽  
Vol 116 (33) ◽  
pp. 16529-16534 ◽  
Author(s):  
Wooseong Kim ◽  
Guijin Zou ◽  
Taylor P. A. Hari ◽  
Ingrid K. Wilt ◽  
Wenpeng Zhu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Membrane Fluidity ◽  
Lipid Bilayers ◽  
Therapeutic Agent ◽  
Md Simulations ◽  
Persister Cells ◽  
Methicillin Resistant ◽  
Bacterial Membranes ◽  
Selective Membrane ◽  
Mrsa Infection

Treatment of Staphylococcus aureus infections is complicated by the development of antibiotic tolerance, a consequence of the ability of S. aureus to enter into a nongrowing, dormant state in which the organisms are referred to as persisters. We report that the clinically approved anthelmintic agent bithionol kills methicillin-resistant S. aureus (MRSA) persister cells, which correlates with its ability to disrupt the integrity of Gram-positive bacterial membranes. Critically, bithionol exhibits significant selectivity for bacterial compared with mammalian cell membranes. All-atom molecular dynamics (MD) simulations demonstrate that the selectivity of bithionol for bacterial membranes correlates with its ability to penetrate and embed in bacterial-mimic lipid bilayers, but not in cholesterol-rich mammalian-mimic lipid bilayers. In addition to causing rapid membrane permeabilization, the insertion of bithionol increases membrane fluidity. By using bithionol and nTZDpa (another membrane-active antimicrobial agent), as well as analogs of these compounds, we show that the activity of membrane-active compounds against MRSA persisters positively correlates with their ability to increase membrane fluidity, thereby establishing an accurate biophysical indicator for estimating antipersister potency. Finally, we demonstrate that, in combination with gentamicin, bithionol effectively reduces bacterial burdens in a mouse model of chronic deep-seated MRSA infection. This work highlights the potential repurposing of bithionol as an antipersister therapeutic agent.

scholarly journals Control of Methicillin-Resistant Staphylococcus aureus Strains Associated With a Hospital Outbreak Involving Contamination From Anesthesia Equipment Using UV-C

2020 ◽  
Vol 11 ◽  
Author(s):  
Sara A. Ochoa ◽  
Ariadnna Cruz-Córdova ◽  
Jetsi Mancilla-Rojano ◽  
Gerardo Escalona-Venegas ◽  
Veronica Esteban-Kenel ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Opportunistic Pathogen ◽  
Type Ii ◽  
Methicillin Resistant ◽  
Hospital Outbreak ◽  
Anesthesia Equipment ◽  
Mrsa Strains ◽  
Healthcare Associated ◽  
Uv C ◽  
Sequence Types

Methicillin-resistant Staphylococcus aureus (MRSA) is considered an opportunistic pathogen in humans and is mainly associated with healthcare-associated infections (HCAIs). This bacterium colonizes the skin and mucous membranes of healthy people and causes frequent hospital outbreaks. The aim of this study was to perform molecular typing of the staphylococcal cassette chromosome mec (SCCmec) and agr loci as wells as to establish the pulsotypes and clonal complexes (CCs) for MRSA and methicillin-sensitive S. aureus (MSSA) outbreaks associated with the operating room (OR) at a pediatric hospital. Twenty-five clinical strains of S. aureus (19 MRSA and 6 MSSA strains) were recovered from the outbreak (patients, anesthesia equipment, and nasopharyngeal exudates from external service anesthesia technicians). These clinical S. aureus strains were mainly resistant to benzylpenicillin (100%) and erythromycin (84%) and were susceptible to vancomycin and nitrofurantoin. The SCCmec type II was amplified in 84% of the S. aureus strains, and the most frequent type of the agr locus was agrII, which was amplified in 72% of the strains; however, the agrI and agrIII genes were mainly detected in MSSA strains. A pulsed-field gel electrophoresis (PFGE) analysis grouped the 25 strains into 16 pulsotypes (P), the most frequent of which was P1, including 10 MRSA strains related to the anesthesia equipment, external service anesthesia technicians, and hospitalized patients. Multilocus sequence typing (MLST) identified 15 sequence types (STs) distributed in nine CCs. The most prevalent ST was ST1011, belonging to CC5, which was associated with the SCCmec type II and agrII type. We postulate that the external service anesthesia technicians were MRSA carriers and that these strains were indirectly transmitted from the contaminated anesthesia equipment that was inappropriately disinfected. Finally, the MRSA outbreak was controlled when the anesthesia equipment disinfection was improved and hand hygiene was reinforced.

scholarly journals Screening for Methicillin-Resistant Staphylococcus aureus Colonization Using Sponges

2015 ◽  
Vol 36 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Chang-Seop Lee ◽  
Bianca Montalmont ◽  
Jessica A. O’Hara ◽  
Alveena Syed ◽  
Charma Chaussard ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Nasal Swab ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Type Ii ◽  
Chain Reaction ◽  
Methicillin Resistant ◽  
Nasal Swabs ◽  
Positive Specimen ◽  
Mrsa Infection ◽  
Polymerase Chain

OBJECTIVENasal swab culture is the standard method for identifying methicillin-resistant Staphylococcus aureus (MRSA) carriers. However, this method is known to miss a substantial portion of those carrying MRSA elsewhere. We hypothesized that the additional use of a sponge to collect skin culture samples would significantly improve the sensitivity of MRSA detection.DESIGNHospitalized patients with recent MRSA infection were enrolled and underwent MRSA screening of the forehead, nostrils, pharynx, axilla, and groin with separate swabs and the forehead, axilla, and groin with separate sponges. Staphylococcal cassette chromosome mec (SCCmec) typing was conducted by polymerase chain reaction (PCR).PATIENTSA total of 105 MRSA patients were included in the study.RESULTSAt least 1 specimen from 56.2% of the patients grew MRSA. Among patients with at least 1 positive specimen, the detection sensitivities were 79.7% for the swabs and 64.4% for the sponges. Notably, 86.4% were detected by a combination of sponges and nasal swab, and 72.9% were detected by a combination of pharyngeal and nasal swabs, whereas only 50.9% were detected by nasal swab alone (P<0.0001 and P=0.0003, respectively). Most isolates had SCCmec type II (59.9%) and IV (35.7%). No correlation was observed between the SCCmec types and collection sites.CONCLUSIONScreening using a sponge significantly improves MRSA detection when used in addition to screening with the standard nasal swab.Infect Control Hosp Epidemiol 2014;36(1): 28–33

scholarly journals Identification of a Novel Variant of Staphylococcal Cassette Chromosome mec, Type II.5, and Its Truncated Form by Insertion of Putative Conjugative Transposon Tn6012

2009 ◽  
Vol 53 (6) ◽  
pp. 2616-2619 ◽  
Author(s):  
Xiao Han ◽  
Teruyo Ito ◽  
Fumihiko Takeuchi ◽  
Xiao Xue Ma ◽  
Michihiko Takasu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Sequence Type ◽  
Type I ◽  
Type Ii ◽  
Truncated Form ◽  
Conjugative Transposon ◽  
Methicillin Resistant ◽  
Novel Variant ◽  
Staphylococcal Cassette Chromosome

ABSTRACT We identified two novel staphylococcal cassette chromosome mec (SCCmec) elements in sequence type 8 methicillin-resistant Staphylococcus aureus strains isolated in Japan: type II.5 SCCmec, whose J1 region was highly homologous to that of type I.2 SCCmec of strain PL72 (previously isolated in Poland), and its J1 region variant caused by the deletion/insertion of putative conjugative transposon Tn6012, identified in four S. aureus genomes.

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