scholarly journals Coagulase Negative Staphylococci (CoNS): A Review

2021 ◽  
pp. 304-315
Author(s):  
Suvarna Sande
Keyword(s):  
Virulence Factors ◽  
Molecular Mechanisms ◽  
Methicillin Resistance ◽  
Clinical Importance ◽  
Diagnostic Techniques ◽  
Cross Resistance ◽  
Coagulase Negative Staphylococcus ◽  
Screening Methods ◽  
Coagulase Negative Staphylococci ◽  
Pathogenic Potential

Coagulase-negative staphylococcus (CoNS) has gained more importance as pathogenic organism for infections in both human and animals. CoNS are especially prevalent in immunocompromised patients, critically ill patients, patients having invasive medical devices. The incidence of CoNS varied across different geographic locations in humans and animals. Also, there are varying antibiotic resistance patterns observed in CoNS species, with high methicillin resistance and cross resistance against many antibiotics. Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus xylosus are the most commonly reported species in various studies. Various virulence factors in CoNS are responsible for enhanced pathogenicity. Because of advancement in diagnostic techniques understanding of molecular mechanisms of CoNS pathogenicity is possible.  Recent advances in identification and typing methods, virulence screening methods will help to assess true pathogenic potential of CoNS species. This review focuses on various CoNS species, their identification and virulence factors and clinical importance.

scholarly journals Species distribution and antibiogram of coagulase negative Staphylococci isolated from various clinical specimens in a tertiary care hospital

2021 ◽  
Vol 7 (3) ◽  
pp. 199-206
Author(s):  
Uma Chikkaraddi ◽  
Namratha W Nandihal
Keyword(s):  
Methicillin Resistance ◽  
Tertiary Care ◽  
Diffusion Method ◽  
Care Hospital ◽  
Coagulase Negative Staphylococci ◽  
Pathogenic Potential ◽  
Antibiotic Resistant ◽  
Clinical Specimens ◽  
Gram Staining ◽  
Life Threatening

Coagulase Negative Staphylococci (CoNS) are common inhabitants of skin and mucous membrane, may act as pathogens causing fatal infections especially in immunocompromised patients. CoNS mainly cause infections involving biofilm on implanted biomaterials. Increase in antimicrobial resistance causes difficulties to treat life threatening infections. Despite their growing importance, their speciation is rarely done. Therefore, the present study is undertaken to identify CoNS to the species level and to know their antibiotic susceptibility pattern along with rate of MRCoNS.250 isolates from various clinical specimens were considered in this study. The isolates were identified by colony morphology, Gram staining, catalase, slide and tube coagulase test. Speciation was done by Novobiocin resistance, urease activity, ornithine decarboxylase, pyrrolidonylarylamidase and aerobic acid production from mannose. The antimicrobial susceptibility was performed by Kirby-Bauer's disc diffusion method as per CLSI guidelines.Among 250 CoNS isolates, commonest species identified was (59.2%) followed by (19.6%) and (12.4%). They were commonly isolated in the age group 21 to 30 years (26.8%) and among males(58%). Total of 33.2% were isolated from pus followed by blood(21.6%). Majority species expressed resistance towards nalidixic acid(97.2%) followed by Penicillin(94%), 74.4% to Amoxicillin-Clavulanic acid and 66.4% to Cotrimoxazole. All the isolates were sensitive to Vancomycin. Methicillin resistance among CoNS was 73.2%. : The increased recognition of pathogenic potential in CoNS and emergence of drug resistance among them demonstrates the need to adopt simple laboratory methods to identify the species and determine the antibiotic resistant patterns to help the clinicians in treating the infections caused by CoNS.

scholarly journals Genes, Pathways, and Mechanisms Involved in the Virulence of Mucorales

Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 317 ◽  
Author(s):  
Carlos Lax ◽  
Carlos Pérez-Arques ◽  
María Isabel Navarro-Mendoza ◽  
José Tomás Cánovas-Márquez ◽  
Ghizlane Tahiri ◽  
...  
Keyword(s):  
Fungal Infection ◽  
Virulence Factors ◽  
High Mortality ◽  
Genetic Study ◽  
Molecular Mechanisms ◽  
Gene Manipulation ◽  
Pathogenic Potential ◽  
Limited Knowledge ◽  
New Genes

The order Mucorales is a group of ancient fungi with limited tools for gene manipulation. The main consequence of this manipulation unwillingness is the limited knowledge about its biology compared to other fungal groups. However, the emerging of mucormycosis, a fungal infection caused by Mucorales, is attracting the medical spotlight in recent years because the treatments available are not efficient in reducing the high mortality associated with this disease. The result of this renewed interest in Mucorales and mucormycosis is an extraordinarily productive effort to unveil their secrets during the last decade. In this review, we describe the most compelling advances related to the genetic study of virulence factors, pathways, and molecular mechanisms developed in these years. The use of a few genetic study models has allowed the characterization of virulence factors in Mucorales that were previously described in other pathogens, such as the uptake iron systems, the mechanisms of dimorphism, and azole resistances. More importantly, recent studies are identifying new genes and mechanisms controlling the pathogenic potential of Mucorales and their interactions with the host, offering new alternatives to develop specific strategies against mucormycosis.

scholarly journals Methicillin-resistant coagulase-negative staphylococci in healthy dogs

2017 ◽  
Vol 62 (No. 9) ◽  
pp. 479-487 ◽  
Author(s):  
J. Siugzdaite ◽  
A. Gabinaitiene
Keyword(s):  
Antimicrobial Resistance ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Diffusion Method ◽  
Coagulase Negative Staphylococcus ◽  
Coagulase Negative Staphylococci ◽  
Phenotypic Properties ◽  
Methicillin Resistant ◽  
Healthy Dogs ◽  
Resistance Rates

The objective of this study was to evaluate the prevalence of coagulase-negative staphylococci in healthy dogs and to determine whether methicillin-resistant staphylococci expressed the mecA gene. Nasal and rectal swab samples were taken from 50 clinically healthy dogs. The prevalence of coagulase-negative staphylococci was evaluated according to phenotypic properties. The agar diffusion method was applied to evaluate antimicrobial resistance and the prevalence of methicillin resistance was determined using PCR analysing the mecA gene. A total of 59 coagulase-negative staphylococcus strains were isolated from the nostrils and rectums of 37 (74%) clinically healthy dogs. The prevalence of coagulase-negative staphylococci in female dogs was significantly higher compared with male dogs (P < 0.05). The results of antimicrobial susceptibility testing showed that 6.7% of the strains were resistant to oxacillin, 23.7% were resistant to penicillin, 22% to ampicillin and 16.9% to erythromycin. The mecA PCR revealed one oxacillin-sensitive and four oxacillin-resistant coagulase-negative staphylococci strains to be mecA carriers. Staphylococcus sciuri (60%) and Staphylococcus warneri (20%) were the most prevalent species among methicillin-resistant coagulase negative staphylococci. High antimicrobial resistance rates for these bacteria were observed against penicillin (100%), ampicillin (100%), oxacillin (80%), erythromycin (80%) and gentamicin (60%). All strains were susceptible to vancomycin and enrofloxacin. It is assumed that methicillin-resistance genes evolved in coagulase-negative staphylococcus and were then horizontally transferred among staphylococci.

scholarly journals Virulence factors and antimicrobial resistance of coagulase-negative staphylococci isolated from drinking water

2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Zuzana Čuvalová ◽  
Monika Pipová ◽  
Miriam Kantíková ◽  
Andrea Brtková ◽  
Jozef Fajber
Keyword(s):  
Drinking Water ◽  
Antimicrobial Resistance ◽  
Virulence Factors ◽  
Slovak Republic ◽  
Meca Gene ◽  
Distribution Networks ◽  
Coagulase Negative Staphylococci ◽  
Pathogenic Potential ◽  
Methicillin Resistant ◽  
Chlorinated Drinking Water

AbstractLittle has been published about the occurrence, speciesidentification, andpathogenicpotentialofcoagulasenegative staphylococci (CoNS) present in drinking water. In this study, ten species were identified among 57 isolates of staphylococci from 756 samples of chlorinated drinking water taken from public distribution networks in the Slovak Republic. S. warneri (37%), S. haemolyticus (23%), and S. saprophyticus ssp. saprophyticus (14%) were identified most frequently. Isolates did not produce coagulase, DNase, or hyaluronidase; production of gelatinase and lecithinase was observed in 28 and 22 isolates, respectively. Genetically encoded ability for production of enterotoxin SED was revealed in two isolates. Among ten antibiotics tested, resistance to ampicillin (66.7%), penicillin (64.9%), and erythromycin (57.9%) were observed most frequently. Resistance to gentamicin, vancomycin, or clindamycin was not confirmed. Production of β-lactamase was observed in 64.9% of isolates. Fourty-two isolates were resistant to two or more antibiotics tested, and eight isolates showed multiresistance. The presence of mecA gene was confirmed in 8 isolates, while PBP2a was revealed in 7. Two isolates of S. epidermidis were identified as methicillin-resistant (MRSE). The results demonstrate that CoNS in chlorinated drinking water may possess virulence factors and show resistance to various antibiotics. Therefore, their pathogenic potential should not be ignored.

Coagulase negative Staphylococcus bacteremia in hematopoietic stem cell transplant recipients: Clinical features and molecular characterization

2021 ◽  
Author(s):  
Yosra Chebbi ◽  
Siwar Frigui ◽  
Anis Raddaoui ◽  
Dorra Belloumi ◽  
Amel Lakhal ◽  
...  
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Hematopoietic Stem Cell Transplant ◽  
Stem Cell Transplant ◽  
Methicillin Resistance ◽  
High Rate ◽  
Coagulase Negative Staphylococcus ◽  
Cell Transplant ◽  
Coagulase Negative Staphylococci ◽  
Hematopoietic Stem

AbstractThe purpose of our study was to investigate the epidemiology of coagulase negative staphylococci (CoNS) responsible for bacteremia in hematopoietic stem cell transplant (HSCT) recipients and to determine the prevalence and the genetic background of methicillin resistance. The prevalence of CoNS bacteremia was 7.4% (54/728), higher in allograft (10.7%) than in autograft (4.7%) recipients. A sepsis or a septic shock were observed in 9% of cases. No deaths were attributable to CoNS bacteremia. The methicillin resistance rate was 81%. All MR-CoNS, harbored mecA gene and 90% were typeable with SCCmec typing using PCR amplification. The SCCmec type IV was the most frequent (44%). Clonal dissemination of MR- Staphylococcus epidermidis strains was limited. Our study showed a low prevalence and favorable outcome of CoNS bacteremia in HSCT recipients with limited clonal diffusion. However, they were associated with a significant rate of severe infections and a high rate of methicillin resistance, mediated by SCCmec IV element in most cases.

scholarly journals GENETIC MECHANISMS OF METHICILLIN RESISTANCE IN STAPHYLOCOCCUS AUREUS (MRSA) AND ITS CAPACITY OF TRANSMISSION: A BRIEF REVIEW

2017 ◽  
Vol 9 (2) ◽  
pp. 29-37
Author(s):  
Maja Velhner ◽  
Gordana Kozoderović ◽  
Ljiljana Suvajdžić ◽  
Dalibor Todorović ◽  
Jelena Petrović
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Methicillin Resistance ◽  
Genetic Regulation ◽  
Human Pathogens ◽  
Spa Typing ◽  
Healthy Human ◽  
Pathogenic Potential ◽  
Mrsa Strains ◽  
Healthcare Associated

Methicillin-resistant Staphylococcus aureus is one of the most important human pathogens. Th ese bacteria have the ability to colonize animals andcross species barriers. Th ree major groups of MRSA strains have emerged. Healthcare associated MRSA and community acquired MRSA strains have potential to spread worldwide and oft en persist in hospitals and communities as clonal strains. Th e livestock-associated MRSA has been isolated from healthy human carriers but also from infected patients all around the world. Molecular typing of staphylococcal cassette chromosome mec (SCCmec), multilocus sequence typing in combination with pulse fi eld gel electrophoresis and spa typing are most frequently used for genetic characterization of MRSA strains. Th e community-acquired MRSA strains are capable of producing Panton Valentine leukocidin (PVL) cytotoxin which is their major virulence determinant. MRSA strains possess a number of virulence factors that are common in other bacteria and it is still not entirely explained which virulence factors or mechanisms of their regulation are important for the pathogenic potential, persistence in the environment or the ability to cause detrimental infection in patients. Recently, as a contribution to the progress of molecular biology, peculiar mechanisms of genetic regulation of virulence genes have been discovered and their role in pathogenesis of infection and epidemiology of MRSA has been studied.

Molecular Processes Involved in Pancreatic Cancer and Therapeutics

2020 ◽  
Vol 14 ◽  
Author(s):  
Subhajit Makar ◽  
Abhrajyoti Ghosh ◽  
Divya ◽  
Shalini Shivhare ◽  
Ashok Kumar ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Molecular Mechanisms ◽  
Early Stage ◽  
Locally Advanced ◽  
Therapeutic Strategies ◽  
Screening Methods ◽  
Pancreatic Cancer Cells ◽  
Systemic Treatments ◽  
Cancer Initiation ◽  
Novel Therapeutic Strategies

: Despite advances in the development of cytotoxic and targeted therapies, pancreatic adenocarcinoma (PAC) remains a significant cause of cancer mortality worldwide. It is also difficult to detect it at an early stage due to numbers of factors. Most of the patients are present with locally advanced or metastatic disease, which precludes curative resection. In the absence of effective screening methods, considerable efforts have been made to identify better systemic treatments during the past decade. This review describes the recent advances in molecular mechanisms involved in pancreatic cancer initiation, progression, and metastasis. Additionally, the importance of deregulated cellular signalling pathways and various cellular proteins as potential targets for developing novel therapeutic strategies against incurable forms of pancreatic cancer is reported. The emphasis is on the critical functions associated with growth factors and their receptors viz. c-MET/HGF, CTHRC1, TGF-β, JAK-STAT, cyclooxygenase pathway, WNT, CCK, MAPK-RAS-RAF, PI3K-AKT, Notch, src, IGF-1R, CDK2NA and chromatin regulation for the sustained growth, survival, and metastasis of pancreatic cancer cells. It also includes various therapeutic strategies viz. immunotherapy, surgical therapy, radiation therapy and chemotherapy.

scholarly journals Healthcare-Associated Laboratory-Confirmed Bloodstream Infections—Species Diversity and Resistance Mechanisms, a Four-Year Retrospective Laboratory-Based Study in the South of Poland

2021 ◽  
Vol 18 (5) ◽  
pp. 2785
Author(s):  
Agnieszka Chmielarczyk ◽  
Monika Pomorska-Wesołowska ◽  
Dorota Romaniszyn ◽  
Jadwiga Wójkowska-Mach
Keyword(s):  
Bloodstream Infections ◽  
Diagnostic Techniques ◽  
Resistance Mechanisms ◽  
Infection Prevention And Control ◽  
The South ◽  
Coagulase Negative Staphylococci ◽  
Aminoglycoside Resistance ◽  
Gram Negative ◽  
Maldi Tof ◽  
Carbapenem Resistant

Introduction: Regardless of the country, advancements in medical care and infection prevention and control of bloodstream infections (BSIs) are an enormous burden of modern medicine. Objectives: The aim of our study was to describe the epidemiology and drug-resistance of laboratory-confirmed BSI (LC-BSIs) among adult patients of 16 hospitals in the south of Poland. Patients and methods: Data on 4218 LC-BSIs were collected between 2016–2019. The identification of the strains was performed using MALDI-TOF. Resistance mechanisms were investigated according to European Committee on Antimicrobial Susceptibility Testing, EUCAST recommendations. Results: Blood cultures were collected from 8899 patients, and LC-BSIs were confirmed in 47.4%. The prevalence of Gram-positive bacteria was 70.9%, Gram-negative 27.8% and yeast 1.4%. The most frequently isolated genus was Staphylococcus (50% of all LC-BSIs), with a domination of coagulase-negative staphylococci, while Escherichia coli (13.7%) was the most frequent Gram-negative bacterium. Over 4 years, 108 (2.6%) bacteria were isolated only once, including species from the human microbiota as well as environmental and zoonotic microorganisms. The highest methicillin resistant Staphylococcus aureus (MRSA) prevalence was in intensive care units (ICUs) (55.6%) but S. aureus with resistance to macrolides, lincosamides and streptogramins B (MLSB) in surgery was 66.7%. The highest prevalence of E. faecalis with a high-level aminoglycoside resistance (HLAR) mechanism was in ICUs, (84.6%), while E. faecium-HLAR in surgery was 83.3%. All cocci were fully glycopeptide-sensitive. Carbapenem-resistant Gram-negative bacilli were detected only in non-fermentative bacilli group, with prevalence 70% and more. Conclusions: The BSI microbiology in Polish hospitals was similar to those reported in other studies, but the prevalence of MRSA and enterococci-HLAR was higher than expected, as was the prevalence of carbapenem-resistant non-fermentative bacilli. Modern diagnostic techniques, such as MALDI-TOF, guarantee reliable diagnosis.

scholarly journals Xyloglucan processing machinery in Xanthomonas pathogens and its role in the transcriptional activation of virulence factors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Plinio S. Vieira ◽  
Isabela M. Bonfim ◽  
Evandro A. Araujo ◽  
Ricardo R. Melo ◽  
Augusto R. Lima ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Model Organism ◽  
Citrus Canker ◽  
Effector Proteins ◽  
Glycoside Hydrolases ◽  
Host Cells ◽  
System A ◽  
Enzymatic Machinery

AbstractXyloglucans are highly substituted and recalcitrant polysaccharides found in the primary cell walls of vascular plants, acting as a barrier against pathogens. Here, we reveal that the diverse and economically relevant Xanthomonas bacteria are endowed with a xyloglucan depolymerization machinery that is linked to pathogenesis. Using the citrus canker pathogen as a model organism, we show that this system encompasses distinctive glycoside hydrolases, a modular xyloglucan acetylesterase and specific membrane transporters, demonstrating that plant-associated bacteria employ distinct molecular strategies from commensal gut bacteria to cope with xyloglucans. Notably, the sugars released by this system elicit the expression of several key virulence factors, including the type III secretion system, a membrane-embedded apparatus to deliver effector proteins into the host cells. Together, these findings shed light on the molecular mechanisms underpinning the intricate enzymatic machinery of Xanthomonas to depolymerize xyloglucans and uncover a role for this system in signaling pathways driving pathogenesis.

scholarly journals Virulence Factors in Coagulase-Negative Staphylococci

Pathogens ◽  
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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