scholarly journals Antimicrobial Resistance Leading to Develop Livestock-Associated Methicillin-Resistant S. aureus, and Its Impact on Human, Animal, and Environment

2021 ◽  
Author(s):  
Muhammad Farooq ◽  
Ifra Siddique ◽  
Zia Ullah

The most important microbe in humans is Staphylococcus aureus, which has caused worldwide dispersion in both nosocomial and community settings. The impact of Gram-positive Staphylococcus Aureuson the host is extremely detrimental to illness development. The life form is noteworthy for its ability to receive anti-toxin protection from a variety of anti-toxin classes. The development and distribution of methicillin-resistant Staphylococcus Aureus (MRSA) strains, which are generally multi-drug resistant in clinics and, as a result, in the population, cause severe mortality and bleakness. The research of MRSA illness transmission has advanced since its underlying event, which necessitates a complete clinical approach to dealing with take on this microorganism. For long term use drug of choice is vancomycine nevertheless its efficacy has been put to the test by rise in opposition. More modern anti-MRSA anti-infection medicines have been approved for clinical usage in the last 10 years or so. The aim of this chapter is to offer related data on the genus Staphylococcus and the evolution of antibiotic resistance in addition a discussion of the most important antibiotic resistance mechanisms. Although they are notorious for causing anti-infection blockage, there is a constant need for exploring innovative MRSA antagonists from various sources, including plants, and assessing non-anti-toxin draws close.

2019 ◽  
Vol 8 (6) ◽  
pp. 816 ◽  
Author(s):  
Kuo-Ti Peng ◽  
Tsung-Yu Huang ◽  
Yao-Chang Chiang ◽  
Yu-Yi Hsu ◽  
Fang-Yi Chuang ◽  
...  

Methicillin-resistant Staphylococcus aureus (MRSA) causes superficial infections such as cellulitis or invasive infections such as osteomyelitis; however, differences in MRSA isolates from cellulitis (CL-MRSA) and from osteomyelitis (OM-MRSA) at the same local area remain largely unknown. A total of 221 MRSA isolates including 106 CL-MRSA strains and 115 OM-MRSA strains were collected at Chang-Gung Memorial Hospital in Taiwan between 2016 and 2018, and their genotypic and phenotypic characteristics were compared. We found that OM-MRSA isolates significantly exhibited higher rates of resistance to multiple antibiotics than CL-MRSA isolates. Genotypically, OM-MRSA isolates had higher proportions of the SCCmec type III, the sequence type ST239, and the spa type t037 than CL-MRSA isolates. Besides the multidrug-resistant lineage ST239-t037-SCCmecIII more prevalent in OM-MRSA, higher antibiotic resistance rates were also observed in several other prevalent lineages in OM-MRSA as compared to the same lineages in CL-MRSA. Furthermore, when prosthetic joint infection (PJI) associated and non-PJI-associated MRSA strains in osteomyelitis were compared, no significant differences were observed in antibiotic resistance rates between the two groups, albeit more diverse genotypes were found in non-PJI-associated MRSA. Our findings therefore suggest that deep infections may allow MRSA to evade antibiotic attack and facilitate the convergent evolution and selection of multidrug-resistant lineages.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Justine Fri ◽  
Henry A. Njom ◽  
Collins N. Ateba ◽  
Roland N. Ndip

Thirty-three (33) isolates of methicillin-resistant Staphylococcus aureus (MRSA) from healthy edible marine fish harvested from two aquaculture settings and the Kariega estuary, South Africa, were characterised in this study. The phenotypic antimicrobial susceptibility profiles to 13 antibiotics were determined, and their antibiotic resistance determinants were assessed. A multiplex PCR was used to determine the epidemiological groups based on the type of SCCmec carriage followed by the detection of staphylococcal enterotoxin-encoding genes sea-sed and the Panton Valentine leucocidin gene (pvl). A high antibiotic resistance percentage (67–81%) was observed for Erythromycin, Ampicillin, Rifampicin, and Clindamycin, while maximum susceptibility to Chloramphenicol (100%), Imipenem (100%), and Ciprofloxacin (94%) was recorded. Nineteen (58%) of the MRSA strains had Vancomycin MICs of ≤2 μg/mL, 4 (12%) with MICs ranging from 4–8 μg/mL, and 10 (30%) with values ≥16 μg/mL. Overall, 27 (82%) isolates were multidrug-resistant (MDR) with Erythromycin-Ampicillin-Rifampicin-Clindamycin (E-AMP-RIP-CD) found to be the dominant antibiotic-resistance phenotype observed in 4 isolates. Resistance genes such as tetM, tetA, ermB, blaZ, and femA were detected in two or more resistant strains. A total of 19 (58%) MRSA strains possessed SCCmec types I, II, or III elements, characteristic of healthcare-associated MRSA (HA-MRSA), while 10 (30%) isolates displayed SCCmec type IVc, characteristic of community-associated MRSA (CA-MRSA). Six (18%) of the multidrug-resistant strains of MRSA were enterotoxigenic, harbouring the see, sea, or sec genes. A prevalence of 18% (6/33) was also recorded for the luk-PVL gene. The findings of this study showed that marine fish contained MDR-MRSA strains that harbour SCCmec types, characteristic of either HA-MRSA or CA-MRSA, but with a low prevalence of enterotoxin and pvl genes. Thus, there is a need for continuous monitoring and implementation of better control strategies within the food chain to minimise contamination of fish with MDR-MRSA and the ultimate spread of the bug.


mSphere ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Morgan L. Grundstad ◽  
Corey P. Parlet ◽  
Jakub M. Kwiecinski ◽  
Jeffrey S. Kavanaugh ◽  
Heidi A. Crosby ◽  
...  

ABSTRACT Methicillin-resistant Staphylococcus aureus (MRSA) infections impact all patient populations both in the community and in health care settings. Despite advances in our knowledge of MRSA virulence, little is known about the regulatory mechanisms of USA100 health care-associated MRSA isolates, which are the second most frequently identified MRSA isolates found in all infections. This work focused on the contribution of the USA100 agr type II quorum-sensing system to virulence and antibiotic resistance. From a MRSA strain collection, we selected 16 representative USA100 isolates, constructed mutants with Δagr mutations, and characterized selected strain pairs for virulence factor expression, murine skin infection, and antibiotic resistance. For each strain pair, hemolysis and extracellular protease expression were significantly greater in the wild-type (WT) strains than in the Δagr mutants. Similarly, mice challenged with the WT strains had larger areas of dermonecrosis and greater weight loss than those challenged with the Δagr mutants, demonstrating that the USA100 agr system regulates virulence. Although USA100 isolates exhibit a high level of antibiotic resistance, the WT and Δagr strain pairs showed no difference in MICs by MIC testing. However, in the presence of a sub-MIC of vancomycin, most of the USA100 Δagr mutants exhibited slower growth than the WT isolates, and a couple of the Δagr mutants also grew more slowly in the presence of a sub-MIC of cefoxitin. Altogether, our findings demonstrate that the USA100 agr system is a critical regulator of virulence, and it may have a contribution to the optimal survival of these MRSA strains in the presence of antibiotics. IMPORTANCE USA100 health care-associated MRSA isolates are highly antibiotic resistant and can cause invasive disease across all patient populations. Even though USA100 strains are some of the most frequently identified causes of infections, little is known about virulence regulation in these isolates. Our study demonstrates that the USA100 agr quorum-sensing system is important for the control of toxin and exoenzyme production and that the agr system has a key role in skin infection. In some USA100 isolates, the agr system is important for growth in the presence of low levels of antibiotics. Altogether, our findings demonstrate that the USA100 agr system is a critical regulator of virulence and that it may make a contribution to the optimal survival of these MRSA strains in the presence of antibiotics.


Toxins ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 119 ◽  
Author(s):  
Assia Mairi ◽  
Abdelaziz Touati ◽  
Jean-Philippe Lavigne

This review assessed the molecular characterization of the methicillin-resistant Staphylococcus aureus (MRSA)-ST80 clone with an emphasis on its proportion of total MRSA strains isolated, PVL production, spa-typing, antibiotic resistance, and virulence. A systematic review of the literature was conducted on MRSA-ST80 clone published between 1 January 2000 and 31 August 2019. Citations were chosen for a review of the full text if we found evidence that MRSA-ST80 clone was reported in the study. For each isolate, the country of isolation, the sampling period, the source of isolation (the type of infection, nasal swabs, or extra-human), the total number of MRSA strains isolated, number of MRSA-ST80 strains, antibiotic resistance patterns, PVL production, virulence genes, and spa type were recorded. The data from 103 articles were abstracted into an Excel database. Analysis of the data showed that the overall proportion of MRSA-ST80 has been decreasing in many countries in recent years. The majority of MRSA-ST80 were PVL positive with spa-type t044. Only six reports of MRSA-ST80 in extra-human niches were found. This review summarizes the rise of MRSA-ST80 and the evidence that suggests that it could be in decline in many countries.


2017 ◽  
Vol 61 (3) ◽  
Author(s):  
Catarina Milheiriço ◽  
Hermínia de Lencastre ◽  
Alexander Tomasz

ABSTRACT Most methicillin-resistant Staphylococcus aureus (MRSA) strains are resistant to beta-lactam antibiotics due to the presence of the mecA gene, encoding an extra penicillin-binding protein (PBP2A) that has low affinity for virtually all beta-lactam antibiotics. Recently, a new resistance determinant—the mecC gene—was identified in S. aureus isolates recovered from humans and dairy cattle. Although having typically low MICs to beta-lactam antibiotics, MRSA strains with the mecC determinant are also capable of expressing high levels of oxacillin resistance when in an optimal genetic background. In order to test the impact of extensive beta-lactam selection on the emergence of mecC-carrying strains with high levels of antibiotic resistance, we exposed the prototype mecC-carrying MRSA strain, LGA251, to increasing concentrations of oxacillin. LGA251 was able to rapidly adapt to high concentrations of oxacillin in growth medium. In such laboratory mutants with increased levels of oxacillin resistance, we identified mutations in genes with no relationship to the mecC regulatory system, indicating that the genetic background plays an important role in the establishment of the levels of oxacillin resistance. Our data also indicate that the stringent stress response plays a critical role in the beta-lactam antibiotic resistance phenotype of MRSA strains carrying the mecC determinant.


Author(s):  
William Lelorel Nguekap Nankam ◽  
Pierre René Fotsing Kwetche ◽  
Gildas Boris Tazemda-Kuitsouc ◽  
Golda Joyce Djeutsa Chouna ◽  
Jean Michel Tekam

Abstract Background Commensal flora colonization during hospitalization by bacteria is the first step for nosocomial infections while antibiotic resistance reduces therapeutic options. In aim to control this phenomenon, we initiated this study to describe the impact of hospitalization on colonization by methicillin-resistant Staphylococcus aureus in the surgical department of 03 health facilities in the Ndé division, West-Cameroon. Methods This study was carried out on patients admitted for surgery in 03 health facilities of the Ndé division, West-Cameroon (District Hospital of Bangangté, Protestant Hospital of Bangwa and Cliniques Universitaires des Montagnes). After obtaining ethical clearance and authorizations, nasal swabs were performed at admission and discharge, with the aim of isolating bacteria and performing their antibiotic susceptibility tests. Informations on each participant's antibiotic therapy were recorded. Laboratory investigations were carried out according to standard protocols (CASFM, 2019). Results The most commonly used antibiotics were β-lactams. A total of 104 nasal swabs were performed on 52 patients who agreed to participate to the study. From the analysis, 110 (57 at admission versus 53 at discharge) Staphylococcus isolates were obtained. Overall, susceptibility testing showed that antibiotic resistance rates were higher at discharge than at admission; with significant differences between the susceptibility profiles obtained at admission and discharge for β-lactams and not significant for fluoroquinolones and aminoglycosides. Globally, frequency of nasal carriage of methicillin-resistant Staphylococcus aureus at discharge 16 (30.77%) was significantly higher than at admission 07 (13.46%) with Chi-2 = 4.52 and p = 0.0335. Conclusion The high rates of antibiotic resistance of bacteria isolated at discharge compared to those isolated at admission obtained in the present investigation, highlights the important role that hospitalization plays in the selection and dissemination of methicillin-resistant Staphylococcus aureus and colonization by these bacteria in health structures of Ndé division. As a result, further investigations to find the factors that promote this phenomenon should be carried out.


Author(s):  
Shengnan Jiang ◽  
Hemu Zhuang ◽  
Feiteng Zhu ◽  
Xiang Wei ◽  
Junxiong Zhang ◽  
...  

The emergence of daptomycin-resistant (DAP-R) Staphylococcus aureus strains has become a global problem. Point mutations in mprF are the main cause of daptomycin (DAP) treatment failure. However, the impact of these specific point-mutations in methicillin-resistant S. aureus (MRSA) strains associated with DAP resistance and the “see-saw effect” of distinct beta-lactams remains unclear. In this study, we used three series of clinical MRSA strains with three distinct mutated mprF alleles from clone complexes (CC) 5 and 59 to explore the “see-saw effect” and the combination effect of DAP plus beta-lactams. Through construction of mprF deletion and complementation strains of SA268, we determined that mprF -S295A, mprF -S337L and one novel mutation of mprF- I348del within the bifunctional domain lead to DAP resistance. Compared with wild-type mprF cloned from a DAP-susceptible (DAP-S) strain, these three mprF mutations conferred the “see-saw effect” to distinct beta-lactams in the SA268Δ mprF strains and mutated- mprF (I348del and S337L) did not alter the cell surface positive charge ( P > 0.05). The susceptibility to beta-lactams increased significantly in DAP-R CC59 strains and the “see-saw effect” was found to be associated with distinct mutated mprF alleles and the category of beta-lactams. The synergistic activity of DAP plus oxacillin was detected in all DAP-R MRSA strains. Continued progress in understanding the mechanism of restoring susceptibility to beta-lactam antibiotics mediated by the mprF mutation and its impact on beta-lactam combination therapy will provide fundamental insights into treatment of MRSA infections.


2019 ◽  
Vol 57 (12) ◽  
Author(s):  
Andrea Álvarez ◽  
Lucía Fernández ◽  
Diana Gutiérrez ◽  
Beatriz Iglesias ◽  
Ana Rodríguez ◽  
...  

ABSTRACT Even though antibiotic resistance in bacteria is a natural phenomenon, the alarming increase in pathogenic bacteria refractory to a wide range of antimicrobials is attracting attention worldwide. Indeed, the World Health Organization (WHO) has recently published a list of priority pathogens for which new antimicrobial alternatives are urgently needed. Among these pathogens, methicillin-resistant Staphylococcus aureus (MRSA) strains are perhaps the best known by the general public. In addition to its potential to acquire antibiotic resistance, S. aureus can produce a large number of virulence factors, such as hemolysins, enterotoxins, and proteases, and exhibits the ability to form biofilms as well as to evolve into different clones that can spread and colonize new environments. This review provides a brief overview of the latest options in antibacterial therapies, mainly focusing on phage therapy. In this regard, the current stage of research about antimicrobial compounds based on bacteriophages and endolysins against MRSA infections is shown and discussed.


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