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Green Metal-Based Nanoparticles Synthesized Using Medicinal Plants and Plant Phytochemicals against Multidrug-Resistant Staphylococcus aureus
Published in Richard L. K. Glover, Daniel Nyanganyura, Rofhiwa Bridget Mulaudzi, Maluta Steven Mufamadi, Green Synthesis in Nanomedicine and Human Health, 2021
Abeer Ahmed Qaed Ahmed, Lin Xiao, Tracey Jill Morton McKay, Guang Yang
MRSA resistance is rooted in the production of a novel low-affinity penicillin-binding protein (PBP2a or PBP2’), which reduces the binding affinities of β-lactam antibiotics (Hartman and Tomasz, 1984; Reynolds and Brown, 1985; Utsui and Yokota, 1985). The mecA gene has been reported responsible for encoding the PBP2a (Jevons, 1961; Katayama et al., 2000). MRSA can continue with cell wall synthesis regardless of the presence of high concentrations of β-lactam antibiotics (Matthews and Tomasz, 1990). The mecA gene that encodes PBP2a is located on MRSA chromosome. The sequence of mecA gene was determined in Japan in 1987, when it was cloned from a MRSA strain (Staphylococcus aureus, TK784) (Song et al., 1987). The mecA gene was found to be distributed among coagulase-negative Staphylococcus strains as well as S. aureus (Hürlimann-Dalel et al., 1992; Suzuki et al., 1992). Therefore, the methicillin resistance determinant (mec) was hypothesized as to being able to transfer freely among Staphylococcal species. This mecA might have entered S. aureus only once or twice (Barry et al., 1993).
Staphylococcus aureus
Published in Firza Alexander Gronthoud, Practical Clinical Microbiology and Infectious Diseases, 2020
Methicillin-resistant S. aureus has a PBP2a instead of a PBP2 in its cell wall. This confers resistance to almost all β-lactams including the semisynthetic penicillins, cephalosporins and carbapenems. PBP2a is encoded by the mecA gene. The mecA gene is located in mobile genetic element called staphylococcal cassette chromosome mec (SCCmec). SCCmec also frequently contains resistance genes to other antibiotics including macrolides, clindamycin and tetracycline. MRSA can spread SCCmec to MSSA through horizontal gene transfer.
Antimicrobial Therapy
Published in John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie, Basic Sciences Endocrine Surgery Rhinology, 2018
Ursula Altmeyer, Penelope Redding, Nitish Khanna
The mecA gene of methicillin-resistant strains of S. aureus (MRSA) encodes for an altered penicillin binding protein called PBP2a, which does not allow attachment of any β-lactam agent and therefore renders the organism resistant to this class of antibiotic.
Identification and characterization of bacteria isolated from patients with cystic fibrosis in Jordan
Published in Annals of Medicine, 2022
Nid’a Alshraiedeh, Farah Atawneh, Rasha Bani-Salameh, Rawan Alsharedeh, Yara Al Tall, Mohammad Alsaggar
Among our isolated S. aureus strains, the highest resistance rates were observed in penicillin (89%; n = 16), followed by erythromycin (83%; n = 15) and oxacillin (67%; n = 12). Methicillin-resistant S. aureus (MRSA) identification and diagnosis in the clinical microbiology environment are critical for both determining effective treatment for individual patients and MRSA surveillance. MRSA strains are defined by the detection of the mecA gene which encodes PBP 2a; an altered penicillin-binding protein that has a low affinity for β-lactam antibiotics. The prevalence of MRSA, defined by detection of the mecA via PCR, was detected among 61% (n = 11) of S. aureus isolates. The slight difference between isolates resistant to oxacillin and mecA-positive isolates could be due to the presence of mecA homologous, such as mecC, emphasizing the need to search for both genetic resistance genes when identifying MRSA. Recently, isolates positive for MRSA but negative for mecA were discovered and found to harbour mecC, a homolog of mecA [22]. All S. aureus isolates were susceptible to gentamicin, doxycycline, and trimethoprim-sulfamethoxazole. In contrast to our findings, low rates of MRSA were reported in different studies conducted in different countries [23–25].
Occurrence, distribution and pattern analysis of methicillin resistant (MRSA) and methicillin sensitive (MSSA) Staphylococcus aureus on fomites in public facilities
Published in Pathogens and Global Health, 2021
Ziad W Jaradat, Maysoon Khwaileh, Waseem Al Mousa, Qutaiba O Ababneh, Anas Al Nabulsi
The presence of mecA gene was used as indicator of the number of MRSA among the confirmed isolates. Testing with PCR revealed that 158 (41.6 %) of the isolates harbored the mecA gene and thus were described as MRSA, while the other 222 (58.42%) tested negative and were described as MSSA. The results showed that MRSA isolates were recovered from all swab sites and public facilities. However, among the total 2600 collected samples, the percentages of MRSA in public facilities were higher in hospital fomites then transportation sites followed by university fomites and schools and least in market samples. According to fomite types, the percentages of MRSA were significantly higher on toilet door handles, student seats and wash rooms in comparison with other fomite types (p > 0.001) (Table 3A). In contrast, percent MSSA of the total isolates were almost the same around 9 for all locations except for transportation were percent MSSA was only 3.2% (Table 3B). Regarding the distribution of MSSA isolates among different fomites, the student disks contained the highest percentage followed by toilet door handles, door handles, markets, washrooms and the others (Table 3B).
Distribution and antibiotic-resistance of different Staphylococcus species identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) isolated from the oral cavity
Published in Journal of Oral Microbiology, 2021
Katarzyna Garbacz, Maria Wierzbowska, Ewa Kwapisz, Maja Kosecka-Strojek, Marek Bronk, Morteza Saki, Jacek Międzobrodzki
Methicillin-resistant staphylococci constitute a major challenge in the treatment of both nosocomial and community-acquired infections. Methicillin resistance is determined by an extra penicillin-binding protein (PBP2a), encoded by the mecA gene. In the present study, the mecA gene was found in 38.5%, 22.2%, 13.5% S. haemolyticus, S. saprophyticus and S. aureus isolates, respectively. The proportions of isolates carrying this gene were nearly thrice as high as reported by Smith et al. [19] but still lower than the rates documented in staphylococcal infections (40–60%) [8,28]. In previous studies, mecA-carriage was frequently demonstrated in CoNS belonging to S. haemolyticus, S. epidermidis, and S. hominis species, which is consistent with our findings [5,30,31]. mecA gene carriage rate in S. saprophyticus (22.3%) was higher than in clinical isolates reported by Cui et al. [28]. The presence of the mecA gene was not observed in some staphylococcal species, such as S. xylosus, S. pasteuri, S. simulans, and S. cohnii, which is consistent with the previous results [32]. The MDR phenotype was widespread among methicillin-resistant CoNS strains, such as S. haemolyticus S. saprophyticus, and S. epidermidis. These results imply that CoNS may constitute a potential reservoir for methicillin resistance and play a role in the inter-species transfer of resistance genes.