scholarly journals Phosphonopeptides Revisited, in an Era of Increasing Antimicrobial Resistance

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1445 ◽  
Author(s):  
Emma C.L. Marrs ◽  
Linda Varadi ◽  
Alexandre F. Bedernjak ◽  
Kathryn M. Day ◽  
Mark Gray ◽  
...  

Given the increase in resistance to antibacterial agents, there is an urgent need for the development of new agents with novel modes of action. As an interim solution, it is also prudent to reinvestigate old or abandoned antibacterial compounds to assess their efficacy in the context of widespread resistance to conventional agents. In the 1970s, much work was performed on the development of peptide mimetics, exemplified by the phosphonopeptide, alafosfalin. We investigated the activity of alafosfalin, di-alanyl fosfalin and β-chloro-L-alanyl-β-chloro-L-alanine against 297 bacterial isolates, including carbapenemase-producing Enterobacterales (CPE) (n = 128), methicillin-resistant Staphylococcus aureus (MRSA) (n = 37) and glycopeptide-resistant enterococci (GRE) (n = 43). The interaction of alafosfalin with meropenem was also examined against 20 isolates of CPE. The MIC50 and MIC90 of alafosfalin for CPE were 1 mg/L and 4 mg/L, respectively and alafosfalin acted synergistically when combined with meropenem against 16 of 20 isolates of CPE. Di-alanyl fosfalin showed potent activity against glycopeptide-resistant isolates of Enterococcus faecalis (MIC90; 0.5 mg/L) and Enterococcus faecium (MIC90; 2 mg/L). Alafosfalin was only moderately active against MRSA (MIC90; 8 mg/L), whereas β-chloro-L-alanyl-β-chloro-L-alanine was slightly more active (MIC90; 4 mg/L). This study shows that phosphonopeptides, including alafosfalin, may have a therapeutic role to play in an era of increasing antibacterial resistance.

2021 ◽  
Vol 10 (1) ◽  
pp. 14-29
Author(s):  
Sembodho Edi Kurniawan ◽  
Mahyarudin Mahyarudin ◽  
Ambar Rialita

ABSTRAKAncaman global pada kasus Methicillin Resistant Staphylococcus aureus (MRSA) membutuhkan alternatif penanganan dengan tanaman obat tradisional. Bakteri endofit pada tanaman pegagan (Centella asiatica) memiliki kemampuan menghasilkan senyawa metabolit sekunder bersifat antibakteri yang serupa dengan tanaman inangnya. Tujuan penelitian ini untuk mengetahui aktivitas antibakteri isolat bakteri endofit daun pegagan (C. asiatica) terhadap S. aureus. Penelitian ini bersifat deskriptif yaitu isolat bakteri endofit daun pegagan (C. asiatica) diujikan dengan metode difusi cakram terhadap S. aureus. Isolat yang paling berpotensi memiliki aktivitas antibakteri dilakukan uji metabolit untuk mengetahui senyawa antibakteri yang dihasilkan. Identifikasi bakteri endofit berdasarkan morfologi koloni, morfologi sel, dan uji biokimia. Hasil penelitian menunjukkan 2 dari 37 isolat memiliki aktivitas terhadap S. aureus  dengan zona hambat sebesar 9,02 mm dan 15,9 mm. Isolat yang paling berpotensi memiliki aktivitas tertinggi yaitu isolat I2 dengan zona hambat sebesar 15,9 mm. Isolat I2 memiliki kemiripan dengan genus Bacillus dan kemampuan mengasilkan senyawa antibakteri seperti alkaloid, saponin dan terpenoid.  Kata kunci: antibakteri; bakteri endofit; Centella asiatica; Staphylococcus aureus   ABSTRACTAntibacterial activity of endophytic bacteria isolate from pegagan leaves (Centella asiatica) against Staphylococcus aureusThe global threat in the case of Methicillin Resistant Staphylococcus aureus (MRSA) requires alternative treatment using traditional medicinal plants. Endophytic bacteria found in Pegagan plants (Centella asiatica) have ability to produce secondary metabolites with antibacterial capabilities similar to their host plants. The purpose of this study is to determine the antibacterial activity of endophytic bacterial isolates of Pegagan (C. asiatica) against S. aureus. This study is a descriptive research where endophytic bacterial isolates of Pegagan leaves (C. asiatica) were tested with disk diffusion method against S. aureus. The most potential isolates with antibacterial activity were performed metabolites test to determine the antibacterial compounds produced. Endophytic bacteria identification based on colony morphology, cell morphology and biochemical tests. The results showed that 2 out of 37 isolates had activity against S. aureus with inhibition zone of 9,02 mm and 15.9 mm. The most potential isolate that has highest activity was I2 isolate with inhibition zone of 15.9 mm. Isolate I2 has similarities with the genus Bacillus and the ability to produce antibacterial compounds such as alkaloids, saponins and terpenoids. Key words: antibacterial; Centella asiatica; endophytic bacteria; Staphylococcus aureus


Author(s):  
K. S. Adebiyi ◽  
F. O. Ehigiamusoe ◽  
C. E. Oshoma

Aim: Methicillin-resistant Staphylococcus aureus (MRSA) and other nosocomial pathogens are frequently isolated from the Radiology Department of hospitals. These pathogens are repeatedly exposed to refracted electromagnetic radiations during diagnostic clinical X-ray imaging sessions. This study thus investigated the effect of these refracted radiations on the nosocomial bacteria found within Radiology units and their possible survival mechanism. Methodology: Swab samples were collected from three (3) Radiology units; plain radiography machine, ultrasound machine and mammography machine. The samples were cultured and identified following standard microbiology procedures. The identified bacterial isolates were exposed to X-rays at different KVp and MAs factors, cell counts and catalase activities of the isolates were determined using standard procedures. Results: The bacterial isolates identified were Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli and Enterococcus faecalis where Staphylococcus aureus had the highest prevalence (29.41%) and Enterococcus faecalis (11.76%) was least. The highest survival level to KVp and MAs exposure was S. aureus with values 11.16 ± 0.86 x103 and 19.50 ± 0.16 x103 cfu/ml respectively while Enterococcus faecalis was least with negative value. There was a positive correlation between catalase activity and cell survival with R-value of 0.2512 and 0.6925 for KVp and MAs exposure factors respectively. Conclusion: The study revealed that clinical X-ray does not completely eliminate nosocomial pathogens within Radiology Department and MRSA is a formidable bacterium in the units.


Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 954
Author(s):  
Vikas Saini ◽  
Charu Jain ◽  
Narendra Pal Singh ◽  
Ahmad Alsulimani ◽  
Chhavi Gupta ◽  
...  

Antimicrobial resistance (AMR) is an emerging public health problem in modern times and the current COVID-19 pandemic has further exaggerated this problem. Due to bacterial co-infection in COVID-19 cases, an irrational consumption of antibiotics has occurred during the pandemic. This study aimed to observe the COVID-19 patients hospitalized from 1 March 2019 to 31 December 2020 and to evaluate the AMR pattern of bacterial agents isolated. This was a single-center study comprising 494 bacterial isolates (blood and urine) that were obtained from patients with SARS-CoV-2 admitted to the ICU and investigated in the Department of Microbiology of a tertiary care hospital in Delhi, India. Out of the total bacterial isolates, 55.46% were gram negative and 44.53% were gram positive pathogens. Of the blood samples processed, the most common isolates were CoNS (Coagulase Negative Staphylococcus) and Staphylococcus aureus. Amongst the urinary isolates, most common pathogens were Escherichia coli and Staphylococcus aureus. A total of 60% MRSA was observed in urine and blood isolates. Up to 40% increase in AMR was observed amongst these isolates obtained during COVID-19 period compared to pre-COVID-19 times. The overuse of antibiotics gave abundant opportunity for the bacterial pathogens to gradually develop mechanisms and to acquire resistance. Since the dynamics of SARS-COV-2 are unpredictable, a compromise on hospital antibiotic policy may ultimately escalate the burden of drug resistant pathogens in hospitals. A shortage of trained staff during COVID-19 pandemic renders it impossible to maintain these records in places where the entire hospital staff is struggling to save lives. This study highlights the extensive rise in the use of antibiotics for respiratory illness due to COVID-19 compared to antibiotic use prior to COVID-19 in ICUs. The regular prescription audit followed by a constant surveillance of hospital infection control practices by the dedicated teams and training of clinicians can improve the quality of medications in the long run and help to fight the menace of AMR.


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