Emerging discrepancies in conventional and molecular epidemiology of methicillin resistant Staphylococcus aureus isolated from bovine milk

Aqib, Amjad Islam; Ijaz, Muhammad; Farooqi, Shahid Hussain; Ahmed, Rais; Shoaib, Muhammad; Ali, Muhammad Muddassir; Mehmood, Khalid; Zhang, Hui

doi:10.1016/j.micpath.2018.01.005

Cited by 21 publications

(15 citation statements)

References 18 publications

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“…These data suggest that the cefoxitin disk-diffusion (CFD) method is a sensitive phenotypic testing used for the identification of MRSA, as previously reported [ 18 ]. This CDF method is able to avoid misdiagnosis that could be the significant factor for the emergence of infections with MRSA [ 23 ] and could lead to the development of resistance against other important available antibiotics. A study from Pakistan reported that 22% of the clinical isolates were misdiagnosed as MRSA [ 24 ].…”

Section: Discussionmentioning

confidence: 99%

Mutation-Based Antibiotic Resistance Mechanism in Methicillin-Resistant Staphylococcus aureus Clinical Isolates

et al. 2021

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β-Lactam antibiotics target penicillin-binding proteins and inhibit the synthesis of peptidoglycan, a crucial step in cell wall biosynthesis. Staphylococcus aureus acquires resistance against β-lactam antibiotics by producing a penicillin-binding protein 2a (PBP2a), encoded by the mecA gene. PBP2a participates in peptidoglycan biosynthesis and exhibits a poor affinity towards β-lactam antibiotics. The current study was performed to determine the diversity and the role of missense mutations of PBP2a in the antibiotic resistance mechanism. The methicillin-resistant Staphylococcus aureus (MRSA) isolates from clinical samples were identified using phenotypic and genotypic techniques. The highest frequency (60%, 18 out of 30) of MRSA was observed in wound specimens. Sequence variation analysis of the mecA gene showed four amino acid substitutions (i.e., E239K, E239R, G246E, and E447K). The E239R mutation was found to be novel. The protein-ligand docking results showed that the E239R mutation in the allosteric site of PBP2a induces conformational changes in the active site and, thus, hinders its interaction with cefoxitin. Therefore, the present report indicates that mutation in the allosteric site of PBP2a provides a more closed active site conformation than wide-type PBP2a and then causes the high-level resistance to cefoxitin.

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Section: Discussionmentioning

confidence: 99%

Mutation-Based Antibiotic Resistance Mechanism in Methicillin-Resistant Staphylococcus aureus Clinical Isolates

et al. 2021

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“…Sin embargo, existen varias cepas enfrentadas con cefoxitina u oxacilina con presunta resistencia a meticilina que no presentaron el gen mecA. Este fenómeno de hetero resistencia puede estar relacionado con la presencia de algún otro marcador asociado con la resistencia, como algunos genes homólogos (Aqib et al, 2018).…”

Section: Discussionunclassified

Caracterización fenotípica y genotípica de Staphylococcus spp con resistencia a meticilina en pollos comerciales

Cotaquispe¹,

Sarmiento²,

Lovón³

et al. 2021

Rev. investig. vet. Perú

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El estudio tuvo como objetivo identificar Staphylococcus spp con fenotipos y genotipos de resistencia a meticilina, así como identificar variantes del polimorfismo del gen coa + en S. aureus. Se utilizaron 97 cepas de Staphylococcus spp aislados de pollos y se hicieron antibiogramas y pruebas de PCR multiplex, PCR convencional y secuenciamiento. Los resultados fenotípicos indican la presencia de resistencia a 2 SARM y 26 SCN resistentes a meticilina (cefoxitina) y 2 S. aureus y 67 SCN con presunta resistencia a meticilina (oxacilina) en las pruebas de antibiograma. Mediante PCR se identificó el gen mecA responsable de la resistencia a meticilina en 24 cepas: 2 SARM y 22 SCNRM y se identificaron cuatro genotipos de S. aureus con variantes del polimorfismo del gen coagulasa. Los resultados sugieren una actividad genética constante, la aparición de clones y la expresión de genes para la resistencia a los principales antibióticos que enfrentan Staphylococcus spp.

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“…Aquib et al (2018) reported a significant discrepancies in mecA dependent methicillin resistance. They reported a significant number of mecA negative MRSA, as well as mecA positive MSSA 33 .…”

Section: Discussionmentioning

confidence: 99%

Antibiotic Sensitivity and Virulence Genes in Staphylococcus aureus Isolates from Surgical Site Infection

Akhter

Akter

Ahsan

et al. 2021

Bangla. J. Microbiol.

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Fourteen multi drug resistant Staphylococcus aureus isolates from surgical site infection were analyzed for their antibiotic sensitivity and the presence of nine virulence genes. The isolates showed a high resistance pattern, all being resistant to methicillin, oxacillin, azithromycin, ceftazidime and amoxyclav. Seven of the isolates were sensitive to linezolid; three were sensitive to trimethoprim: sulfamethoxazol and another three were sensitive to ciprofloxacin. Ceftriaxone, gentamicin and amikacin were the drugs of choice as nine (64.3%) isolates were sensitive to ceftriaxone, eleven (78.6%) were sensitive to gentamicin and another eleven (78.6%) to amikacin. The present study focused to identify nine important virulence genes including intrinsic methicillin resistance gene mecA, methicillin resistance assisting gene femA, toxic shock syndrome toxin gene tst, exfoliative toxin A and B genes, eta and etb, Panton Valentine leukocidin gene LukS/F-PVL, along with three enterotoxin genes sec, sed and see. According to the presence of mecA gene and antibiotic resistance profile, two isolates were identified as methicillin resistant Staphylococcus aureus. However, another isolate, despite harbouring both mecA and femA genes, was sensitive to ceftriaxone which excluded it from being considered as an MRSA. Thus, the ratio of MRSA can be considered to be quite high (2/14) among the strains. Interestingly, most of the isolates (10/14) harboured femA gene, the majority of which were mecA negative with an MSSA type antibiotic profile. Although considered as a marker for community acquired MRSA, LukS/F-PV was found in half of these nosocomial isolates. Five, four and two of the isolates harboured etb, tst and sec gene, respectively. However, all the isolates were negative for eta, sed and see genes. Two isolates showed the co-existance of “femA, LukS/F-PV, etb, and tst” genes. Another two virulence gene patterns observed were “femA, mecA, tst, sec” and “femA, LukS/F-PV, etb”. The presence of several virulence genes can be correlated to the highly pathogenic nature of the isolates. Bangladesh J Microbiol, Volume 38, Number 1, June 2021, pp 21-26

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Emerging discrepancies in conventional and molecular epidemiology of methicillin resistant Staphylococcus aureus isolated from bovine milk

Cited by 21 publications

References 18 publications

Mutation-Based Antibiotic Resistance Mechanism in Methicillin-Resistant Staphylococcus aureus Clinical Isolates

Mutation-Based Antibiotic Resistance Mechanism in Methicillin-Resistant Staphylococcus aureus Clinical Isolates

Caracterización fenotípica y genotípica de Staphylococcus spp con resistencia a meticilina en pollos comerciales

Antibiotic Sensitivity and Virulence Genes in Staphylococcus aureus Isolates from Surgical Site Infection

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