scholarly journals Correlation between mazEF Toxin-Antitoxin System Expression and Methicillin Susceptibility in Staphylococcus aureus and Its Relation to Biofilm-Formation

2021 ◽  
Vol 9 (11) ◽  
pp. 2274
Author(s):  
Aya Abd El rahman ◽  
Yasmine El kholy ◽  
Rania Y. Shash
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Methicillin Resistance ◽  
Diffusion Method ◽  
P Value ◽  
Sequence Motifs ◽  
University Hospitals ◽  
Specific Sequence ◽  
Disk Diffusion Method ◽  
Cellular Mrnas

Methicillin resistance in Staphylococcus aureus has become prevalent globally. Moreover, biofilm-formation makes it more difficult to eradicate bacteria by antibiotics. The mazEF toxin-antitoxin system encodes for mazF, which acts as an endoribonuclease that cleaves cellular mRNAs at specific sequence motifs (ACA), and mazE, which opposes the mazF action. Our goal was to detect mazEF expression in methicillin-resistant S. aureus (MRSA) isolates compared with methicillin-sensitive S. aureus (MSSA) isolates and determine its relation to methicillin susceptibility as well as biofilm-formation. According to their susceptibility to cefoxitin disks, 100 S. aureus isolates obtained from patients admitted to Cairo University Hospitals were categorized into 50 MSSA and 50 MRSA according to their susceptibility to cefoxitin disks (30 µg). Antimicrobial susceptibility and biofilm-formation were investigated using the disk diffusion method and tissue culture plate method, respectively. Finally, using real-time PCR, mazEF expression was estimated and correlated to methicillin susceptibility and biofilm formation. Both MRSA and MSSA isolates showed the best sensitivity results with linezolid and gentamicin, where about 88% of MRSA isolates and 96% of MSSA isolates were sensitive to linezolid while 76% of MRSA isolates and 84% of MSSA isolates were sensitive to gentamicin. MRSA isolates were significantly more able to form biofilm than MSSA isolates (p-value = 0.037). The mazEF expression was significantly correlated to methicillin resistance in S. aureus (p-value < 0.001), but not to biofilm-formation.

scholarly journals Biofilm Formation and Methicillin Resistance of Staphylococcus aureus Isolated from Clinical Samples

10.3823/841 ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Abdelraouf A. Elmanama ◽  
Islam Majdi Al-Aydi ◽  
Mariam R. Al-Reefi
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Resistance ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Methicillin Resistance ◽  
Gaza Strip ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Disk Diffusion Method ◽  
High Tendency

Background: Staphylococcus aureus including methicillin resistant S. aureus (MRSA) is one of the most effective biofilm-forming organisms, biofilm contribute in protecting the microorganism from host defenses and prevent the effective penetration of antimicrobial agents. Biofilm formation is considered as an important contributing factor for the initiation and establishment of chronic infection by S. aureus and known as a major obstacle in the treatment of S. aureus infections is their ability to develop resistance to antimicrobials. Aims : To screen clinical Staphylococcus aureus including MRSA isolates for their biofilm forming abilities and their association with antimicrobial resistance. Methods: A total of 196 clinical isolates of S. aureus were obtained from different sample sources using standard microbiological techniques from three major hospitals in Gaza strip. Biofilm formation of these isolates was determined by tissue culture plate (TCP) method and tube adherence method (TM). Antimicrobial susceptibility test was performed using the modified Kirby–Bauer disk diffusion method as per Clinical and Laboratory Standards Institute guidelines. MRSA was detected using the cefoxitin disk test. Results: Biofilm formation was observed in 174 (88.8 %) and in 145 (74.0%) isolates of S. aureus via TCP method and TM, respectively. The highest resistance percent was for penicillin (92.9%), followed by cefoxitin (80.6%) and oxacillin (67.9%), while the lowest resistance percent was for linezolid and ceftaroline (1%). Among the 196 isolates 71.4% (N=140) were classified as MDR with a MAR index (≥ 0.2). A total of 158 isolates (80.6%) were identified as MRSA distributed as 90.4%, 79.4% and 70.9% from Al-Shifa, Al-Nasser pediatrics and Al-Aqsa hospitals respectively. Large proportions (82.1%) of biofilm producers were identified as MRSA. Biofilm-producing MRSA exhibited a higher percent (90.5%) when compared with the biofilm non-producer MRSA (9.5%). Importantly, 89.2% of biofilm-producing S. aureus were multidrug resistant. Conclusions: S. aureus isolates possessed high biofilm-forming ability. Biofilm-producing strains have very high tendency to exhibit antimicrobial resistance, multidrug resistance and methicillin resistance. Regular surveillance of biofilm formation by S. aureus and their antimicrobial resistance profile may lead more success in treating S. aureus infections.   Keywords: Biofilm, MDR, MRSA, TCP, TM, Gaza strip, Palestine.

scholarly journals Methicillin-resistant Staphylococcus aureus bloodstream infection: risk factors and clinical outcome in non-intensive-care units

2012 ◽  
Vol 45 (2) ◽  
pp. 189-193 ◽  
Author(s):  
Karinne Spirandelli Carvalho Naves ◽  
Natália Vaz da Trindade ◽  
Paulo Pinto Gontijo Filho
Keyword(s):  
Risk Factors ◽  
Staphylococcus Aureus ◽  
Bloodstream Infection ◽  
Antimicrobial Agents ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Methicillin Resistant ◽  
Staphylococcus Aureus Bloodstream Infection

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is spread out in hospitals across different regions of the world and is regarded as the major agent of nosocomial infections, causing infections such as skin and soft tissue pneumonia and sepsis. The aim of this study was to identify risk factors for methicillin-resistance in Staphylococcus aureus bloodstream infection (BSI) and the predictive factors for death. METHODS: A retrospective cohort of fifty-one patients presenting bacteraemia due to S. aureus between September 2006 and September 2008 was analysed. Staphylococcu aureus samples were obtained from blood cultures performed by clinical hospital microbiology laboratory from the Uberlândia Federal University. Methicillinresistance was determined by growth on oxacillin screen agar and antimicrobial susceptibility by means of the disk diffusion method. RESULTS: We found similar numbers of MRSA (56.8%) and methicillin-susceptible Staphylococcus aureus (MSSA) (43.2%) infections, and the overall hospital mortality ratio was 47%, predominantly in MRSA group (70.8% vs. 29.2%) (p=0.05). Age (p=0.02) was significantly higher in MRSA patients as also was the use of central venous catheter (p=0.02). The use of two or more antimicrobial agents (p=0.03) and the length of hospital stay prior to bacteraemia superior to seven days (p=0.006) were associated with mortality. High odds ratio value was observed in cardiopathy as comorbidity. CONCLUSIONS: Despite several risk factors associated with MRSA and MSSA infection, the use of two or more antimicrobial agents was the unique independent variable associated with mortality.

scholarly journals In Vitro Activities of 28 Antimicrobial Agents against Staphylococcus aureus Isolates from Tertiary-Care Hospitals in Korea: a Nationwide Survey

2004 ◽  
Vol 48 (4) ◽  
pp. 1124-1127 ◽  
Author(s):  
Hong Bin Kim ◽  
Hee-Chang Jang ◽  
Hee Jung Nam ◽  
Yeong Seon Lee ◽  
Bong Su Kim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Methicillin Resistance ◽  
Tertiary Care ◽  
Nationwide Survey ◽  
Resistance Rate ◽  
Current Status ◽  
Diffusion Method ◽  
Disk Diffusion Method

ABSTRACT Staphylococcus aureus, one of the most frequently isolated pathogens in both hospitals and the community, has been particularly efficient at developing resistance to antimicrobial agents. As methicillin-resistant S. aureus (MRSA) has prevailed and, furthermore, as S. aureus with reduced susceptibility to vancomycin has emerged, the therapeutic options for the treatment of S. aureus infections have become limited. To update the current status of antibiotic resistance, clinical S. aureus isolates were collected from eight university-affiliated hospitals from June 1999 to January 2001. Susceptibility tests with 28 antibiotics were performed by the disk diffusion method. Among a total of 682 isolates, the methicillin resistance rate was 64% (439 of 682), and most of the MRSA isolates were resistant to multiple classes of antibiotics. Although a constitutive macrolide-lincosamide-streptogramin B resistance phenotype was common, no isolates were resistant to quinupristin-dalfopristin or linezolid. Rifampin, fusidic acid, trimethoprim-sulfamethoxazole, and arbekacin showed superior in vitro activity compared with the other antibiotics against the MRSA isolates. No isolates showed reduced susceptibility to vancomycin.

scholarly journals Antibiotic susceptibility of human-associated Staphylococcus aureus and its relation to agr typing, virulence genes, and biofilm formation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Safoura Derakhshan ◽  
Masoumeh Navidinia ◽  
Fakhri Haghi
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Antibiotic Susceptibility ◽  
Biofilm Formation ◽  
Virulence Genes ◽  
Production Capacity ◽  
Diffusion Method ◽  
Accessory Gene ◽  
Disk Diffusion Method ◽  
The Impact

Abstract Background and objective Carriage of virulence factors confers some evolutionary benefit to bacteria, which favors the resistant strains. We aimed to analyze whether antibiotic susceptibility of Staphylococcus aureus strains is affected by agr typing, biofilm formation ability, and virulence profiles. Methods A total of 123 S. aureus clinical isolates were subjected to antimicrobial susceptibility testing by disk diffusion method, biofilm formation by microtiter plate method, as well as polymerase chain reaction screening to identify virulence genes and the accessory gene regulator (agr) types I-IV. A P value < 0.05 was considered significant. Results The most prevalent virulence gene was staphyloxanthin crtN, followed by hemolysin genes, capsular cap8H, toxic shock toxin tst, and enterotoxin sea, respectively. Resistant isolates were more commonly found in the agr-negative group than in the agr-positive group. Isolates of agr type III were more virulent than agr I isolates. Strong biofilm producers showed more antibiotic susceptibility and carried more virulence genes than non-strong biofilm producers. Associations were found between the presence of virulence genes and susceptibility to antibiotics. Carriage of the virulence genes and agr was higher in the inpatients; while, resistance and strong biofilms were more prevalent in the outpatients. Conclusion These findings indicated the presence of several virulence factors, biofilm production capacity, agr types and resistance to antibiotics in clinical S. aureus isolates. Considering the importance of S. aureus for human medicine, an understanding of virulence and resistance relationships would help to reduce the impact of S. aureus infections.

scholarly journals Panton Valentine Gene in both Community-acquired and Healthcare-acquired Methicillin Resistant Staphylococcus aureus Isolates from Ain Shams University Hospitals

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
R A Mohamed ◽  
L F Fathi ◽  
N N Salaheldeen
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Cross Sectional Study ◽  
P Value ◽  
University Hospitals ◽  
Cross Sectional ◽  
Mannitol Salt Agar ◽  
Methicillin Resistant

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen that is associated with both hospital and community infections. Panton Valentine leukocidin (PVL) is an important virulence factor of S. aureus that is considered by many authors a marker of community acquired MRSA (CA-MRSA). Aim of the Work This study aimed to determine the prevalence of PVL genes among healthcare acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) and CA-MRSA isolates, and to test the hypothesis that PVL is a reliable marker of CA-MRSA isolates. Material and Methods This comparative cross-sectional study was done on fifteen community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) and fifteen hospital acquired methicillin resistant Staphylococcus aureus (HA-MRSA), obtained from patients attending outpatient clinics, presenting with community-acquired pyogenic infections and patients with healthcare acquired pyogenic infections in Intensive Care Units (ICUs), during the period from May 2017 till February 2018. Clinical specimens included pus and different body fluids. Staphylococcus aureus was isolated and identified using conventional microbiological methods3. Isolates were then tested for methicillin resistance by culture on mannitol salt agar (MSA) with cefoxitin4. The presence of mecA and pvl genes in all MRSA isolates was subsequently detected by PCR5,6. Results Among 15 HA-MRSA isolates, mecA gene was positive in 40% (6/15) of isolates, while pvl gene was positive in 53.3% (8/15) of isolates. Among 15 CA-MRSA isolates, mecA gene was positive in 46.7% (7/15) of isolates, while pvl gene was positive in 26.7% (4/15) of isolates. Conclusion We conclude that pvl gene is not a sole genetic marker for diagnosis CA-MRSA, as there was no significant correlation between mecA that encodes for methicillin resistance and pvl genes among fifteen CA-MRSA isolates (P value =1).

MrkD Gene as a Regulator of Biofilm Formation with Correlation to Antibiotic Resistance among Clinical Klebsiella pneumoniae Isolates from Menoufia University Hospitals

2020 ◽  
Vol 29 (3) ◽  
pp. 137-144
Author(s):  
Asmaa M. Elbrolosy ◽  
Naira A. Eissa ◽  
Nahed A. Al-Rajhy ◽  
Esraa El-Sayed A. El-Mahdy ◽  
Rasha G. Mostafa
Keyword(s):  
Antibiotic Resistance ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
University Hospitals ◽  
Pcr Assay ◽  
Disk Diffusion Method ◽  
Microbiological Methods

Background: Klebsiella pneumoniae (K. pneumoniae) is a common pathogen involved in a diverse array of life-threatening infections. Increasing frequent acquisition of antibiotic resistance by K. pneumoniae has given rise to multidrug-resistant pathogen mostly at the hospital level. Objectives: To assess the prevalence and antibiotic resistance pattern of the clinical K. pneumoniae isolates at Menoufia University Hospitals (MUHs) as well as to explore the role of mrkD gene as a regulator of biofilm formation. Methodology: A total of 340 different clinical samples were obtained from 270 patients who were admitted to MUHs and those from Outpatient clinics during the period from April 2018 to September 2019. 84 K. pneumoniae isolates were identified by the standard microbiological methods and vitek-2 system. The antimicrobial resistance pattern was determined by disk diffusion method. The biofilm-forming ability of all K. pneumoniae isolates was demonstrated phenotypically by the modified Congo red agar method (MCRA) and PCR assay verified the presence of mrkD gene as a genetic determinant of biofilm formation. Results: Klebsiella spp. represented 34.7% of the collected isolates and the predominant spp. was K. pneumoniae (91.3%). The highest resistance rates were for ceftriaxone (69%) followed by aztreonam (67.9%), 66.7% for each of piperacillin and ceftazidime, while the least resistance rate was for fosfomycin (8.3%). Biofilm production was detected among 83.3% of the isolates by MCRA method. A highly significant statistical difference was noted between biofilm- and non- biofilm - producing K. pneumoniae isolates regarding resistance to cefepieme and amikacin (P <0.001) and similarly regarding resistance to aztreonam, imipenem, meropenem, ertapenem and tobramycin (P<0.05). Conventional PCR assay showed that, 92% of the isolates harbored mrkD gene with a highly significant association with biofilm formation. Conclusion: The increasing prevalence and remarkable ability to acquire antibiotic resistance among K. pneumoniae isolates together with biofilm formation should alert even more regarding the hazard of this pathogen in hospital settings.

EVALUATION OF THE METHOSD FOR DETECTION METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS.

2013 ◽  
pp. 25-31
Author(s):  
Thi Kim Chi Nguyen ◽  
Dinh Binh Tran ◽  
Thi Nam Lien Nguyen ◽  
Van Tuan Mai ◽  
Godreuil Sylvain
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Antibiotic Sensitivity ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Antibiotic Resistant ◽  
Methicillin Resistant ◽  
Resistant Strains

Objective: To evaluate the infections that caused by Methicillin-resistant Staphylococcus aureus and the value of the tests to detect Methicillin-resistant Staphylococcus aureus. Subjects and Methods: Used routine techniques to culture and isolate S.aureus, test the antibiotic sensitivity by Kirby-Bauerr, determination the Methicillin-resistant Staphylococcus aureus by Oxacillin and cefoxitin disc and PCR in identified the mecA gene Staphylococcus aureus. Results: The rate of Staphylococcus aureus isolated is highest which isolated from pus specimens (55.06%). In 267 strains of Staphylococcus aureus isolated in the Department of Microbiology, Hue Central Hospital the Methicillin resistance Staphylococcus aureus was 61.42%. The level of antibiotic resistant strains of Methicillin-resistant Staphylococcus aureus is higher than that in Methicillin-sensitive strains. Conclusion: Cefoxitin 30 microg disk diffusion method to detect Methicillin resistance is effective for determinate Methicillin-resistant Staphylococcus aureus (sensitivity and specificity are all 100.00%). Key words: Staphylococcus aureus Methicillin-resistant.

Molecular characterization and detection of enterotoxins, methicillin resistance genes and antimicrobial resistance of Staphylococcus aureus from fish and ground beef

2017 ◽  
Vol 20 (1) ◽  
pp. 85-94 ◽  
Author(s):  
S. Arslan ◽  
F. Özdemir
Keyword(s):  
Staphylococcus Aureus ◽  
Sparus Aurata ◽  
Methicillin Resistance ◽  
Ground Beef ◽  
Diffusion Method ◽  
Biochemical Tests ◽  
Disk Diffusion Method ◽  
Enterotoxin Genes ◽  
Meat Samples ◽  
Coa Gene

AbstractA total of 120 samples including 40 freshwaterfish(Oncorhynchus mykiss), 40 seawater fish (Sparus aurata) and 40 ground beef samples were examined for the presence of Staphylococcus aureus. The isolates were identified using biochemical tests and a PCR for the species-specific fragment (Sa442) and thermonuclease gene (nucA). The presence of staphylococcal enterotoxin genes (sea, seb, sec, sed and see), toxin genes (eta, etb, tsst), methicillin resistance gene (mecA) and some phenotypic virulence factors was also tested. Genotypic characterization of the isolates was analyzed by PCR-RFLP of the coa gene. Overall, 36 (30%) meat samples were contaminated with S. aureus. Of the 36 isolates, 3 (8.3%) were found to be positive for enterotoxin genes. Only 1 isolate (5.9%) from ground beef had the sea gene. In addition, 1 (12.5%) of the freshwater fish and 1 (9.1%) of the seawater fish carried both the sea and sed genes. The presence of seb, sec, see, eta, etb and tsst was not detected among the isolates of S. aureus. The amplified coa gene revealed five different clusters. Seven and six distinct RFLP patterns were obtained with AluI and HaeIII digestion, respectively. All isolates were found to be positive for slime, hemolytic and DNase activity while 41.7% of them were beta-lactamase positive. The presence of methicillin resistance was neither detected by PCR nor the disk diffusion method. A total of 94.4% of the isolates were resistant to at least one antimicrobial while 44.4% of them were resistant to at least two or more antimicrobials.

scholarly journals Prevalence and antimicrobial drug resistance of Staphylococcus aureus isolated from cow milk samples

2020 ◽  
Vol 13 (12) ◽  
pp. 2736-2742
Author(s):  
Matlale Phriskey Mphahlele ◽  
James Wabwire Oguttu ◽  
Inge-Marie Petzer ◽  
Daniel Nenene Qekwana
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Methicillin Resistance ◽  
Multidrug Resistant ◽  
Cow Milk ◽  
Diffusion Method ◽  
Biochemical Tests ◽  
Disk Diffusion Method ◽  
Antimicrobial Drug Resistance ◽  
Milk Samples

Background and Aim: Staphylococcus aureus infections and antimicrobial resistance (AMR) in mastitis cases are both of clinical and economic importance. This study investigated the prevalence and AMR patterns of S. aureus isolated from composite milk samples of dairy cows submitted to the Onderstepoort Milk Laboratory for routine diagnosis. Materials and Methods: A total of 2862 cow milk samples randomly selected from submitted samples were tested for the presence of S. aureus using microbiological and biochemical tests. Confirmation of isolates was done using the analytical profile index. Antimicrobial susceptibility of S. aureus isolates against 12 antimicrobial agents was determined using the disk diffusion method. Results: S. aureus was isolated from 1.7% (50/2862) of the samples tested. All (100%) S. aureus isolates were resistant to at least one antimicrobial, while 62% (31/50) were resistant to three or more categories of antimicrobials (multidrug-resistant [MDR]). Most S. aureus isolates were resistant to erythromycin (62%; 31/50) and ampicillin (62%; 31/50). Almost half of S. aureus isolates were resistant to oxacillin (46%; 23/50) and only 8% (4/50) were resistant to cefoxitin. Conclusion: Although the prevalence of S. aureus among mastitis cases in this study was low, isolates exhibited high resistance to aminoglycosides, macrolides, and penicillins, all of which are important drugs in human medicine. The high prevalence of MDR S. aureus and the presence of methicillin resistance among S. aureus observed in this study are of both clinical and public health concerns.

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