scholarly journals Protein extracts from streptomyces sps. inhibits beta-lactamases secreted by pathogenic bacteria

Author(s):  
Rohit Mani Yadava ◽  
Manjula Ishwara Kalyani

<p>Beta-lactamases are enzymes produced by pathogenic microorganisms which exhibit resistance to beta-lactam group of antibiotics and are of considerable clinical importance. In our study, we examined the pathogenic organisms for the secretion of beta-lactamase using the antibiotic ampicillin. The extracted beta-lactamase from the isolates was characterized biochemically for enzyme activity and to initiate their inhibition activities.  The protein extracts separated from the potential actinomycetes species were analyzed by targeting against the beta lactamase enzyme activity. The beta-lactamase enzymes from bacterial isolates were purified from the cell free culture extract and activity was estimated spectrophotometrically.<em>  </em>The actinomycetes isolated from the soil source were tested for their efficiency to inhibit the beta-lactamase enzyme activity. The protein fractions were extracted by salt precipitation using ammonium sulfate and further salt removal by dialysis technique. The assays for enzyme inhibition were performed by plate well diffusion along with absorbance readings of the enzyme and substrate using spectrophotometer. The beta-lactamase enzyme activity of <em>Proteus</em> sp. had shown highest enzymatic activity followed by <em>Staphylococcus aureus </em>and <em>Pseudomonas </em>sp<em>. </em>The protein extracts of four actinomycetes isolates that showed beta-lactamase inhibition were identified belonging to the genus <em>Streptomyces </em>based on their colony morphology, microscopic observation, and biochemical tests. The beta-lactamase inhibition activities were analyzed to combat antibiotitc resistances exerted by the pathogenic bacteria in infections.</p><p> </p>

Author(s):  
Kavi Aniis ◽  
Rajamanikandan Kcp ◽  
Arvind Prasanth D

<p>ABSTRACT<br />Objective: Beta-lactams are the group of antibiotics that contain a ring called as “beta-lactam ring,” which is responsible for the antibacterial activity.<br />The presence of resistance among Gram-negative organisms is due to the production of beta-lactamases enzymes that hydrolysis the beta-lactam ring<br />thereby conferring resistance to the organism. This study is undertaken to determine the prevalence of extended-spectrum beta-lactamase (ESBL)<br />producing Gram-negative organism from clinical samples.<br />Methods: A total of 112 clinical samples were taken for this study. The combined disc synergistic test (CDST) was used for the phenotypic detection<br />of ESBL producers from the clinical samples. The genotypic identification of ESBL producers was carried out by alkaline lysis method by isolation of<br />plasmid DNA.<br />Result: A total of 87 bacterial isolates were isolated and identified. Among them, Klebsiella (41%) was the predominant organism followed by<br />Escherichia coli (33%), Proteus (10%), Pseudomonas (10%), and Serratia (6%). Among the various bacterial isolates, Klebsiella showed a higher<br />percentage of resistance. The CDST showed that 8 isolates of Klebsiella, 3 isolates of E. coli, and 1 isolate of Pseudomonas were found to be ESBL<br />producers. The genotypic confirmation showed that the two bacterial isolates, namely, Klebsiella and E. coli were found to possess temoniera (TEM)<br />gene which was the 400-500 bp conferring resistance to the antibiotics.<br />Conclusion: The results of this study suggest that early detection of ESBL producing Gram-negative organism is a very important step in planning the<br />therapy of patient in Hospitals. CDST continues to be a good indicator in the detection of ESBL producers.<br />Keywords: Beta-lactamases, Gram-negative bacilli, Extended-spectrum beta-lactamase, Resistance, Combined disc synergistic test.</p><p> </p>


1988 ◽  
Vol 1 (1) ◽  
pp. 109-123 ◽  
Author(s):  
K Bush

beta-Lactamases constitute the major defense mechanism of pathogenic bacteria against beta-lactam antibiotics. When the beta-lactam ring of this antibiotic class is hydrolyzed, antimicrobial activity is destroyed. Although beta-lactamases have been identified with clinical failures for over 40 years, enzymes with various abilities to hydrolyze specific penicillins or cephalosporins are appearing more frequently in clinical isolates. One approach to counteracting this resistance mechanism has been through the development of beta-lactamase inactivators. beta-Lactamase inhibitors include clavulanic acid and sulbactam, molecules with minimal antibiotic activity. However, when combined with safe and efficacious penicillins or cephalosporins, these inhibitors can serve to protect the familiar beta-lactam antibiotics from hydrolysis by penicillinases or broad-spectrum beta-lactamases. Both of these molecules eventually inactivate the target enzymes permanently. Although clavulanic acid exhibits more potent inhibitory activity than sulbactam, especially against the TEM-type broad-spectrum beta-lactamases, the spectrum of inhibitory activities are very similar. Neither of these inhibitors acts as a good inhibitor of the cephalosporinases. Clavulanic acid has been most frequently combined with amoxicillin in the orally active Augmentin and with ticarcillin in the parenteral beta-lactam combination Timentin. Sulbactam has been used primarily to protect ampicillin from enzymatic hydrolysis. Sulbactam has been used either in the orally absorbed prodrug form as sultamicillin or as the injectable combination ampicillin-sulbactam. Synergy has been demonstrated for these combinations for most members of the Enterobacteriaceae, although those organisms that produce cephalosporinases are not well inhibited. Synergy has also been observed for Neisseria gonorrhoeae, Haemophilus influenzae, penicillinase-producing Staphylococcus aureus, and anaerobic organisms. These antibiotic combinations have been used clinically to treat urinary tract infections, bone and soft-tissue infections, gonorrhea, respiratory infections, and otitis media. Gastrointestinal side effects have been reported for Augmentin and sultamicillin; most side effects with these agents have been mild. Although combination therapy with beta-lactamase inactivators has been used successfully, the problem of resistance development to two agents must be considered. Induction of cephalosporinases can occur with clavulanic acid. Permeability mutants could arise, especially with added pressure from a second beta-lactam.(ABSTRACT TRUNCATED AT 250 WORDS)


2020 ◽  
Vol 10 (1) ◽  
pp. 1-4
Author(s):  
Omor Ahmed Chowdhury ◽  
Md Raihan Ahmed ◽  
Md Raihan Dipu ◽  
Md Aftab Uddin

The use of earphones has increased in recent times throughout the world especially among the different level of students such as school, college or university who have a higher tendency of sharing these among them. Unlike airline headsets, headphones and stethoscope ear-pieces, ear phones are often shared by multiple users and can be a potential medium for transmission of pathogens, which can give rise to various ear related infections. The objective of this study was to detect the pathogenic bacteria from the ear-phones used by the students of Stamford University Bangladesh. A total of 16 ear-phone swabs were collected by sterile cotton swabs. The swabs were inoculated onto blood agar and incubated aerobically overnight at 37oC. Microscopic observation and standard biochemical tests were performed to confirm the identification of all the bacterial isolates. Six presumptively identified Staphylococcus spp. (38%) were tested against six different types of antibiotics following Kirby-Bauer disk diffusion method. Isolates were found to be 84% resistant against Cotrimoxazole and demonstrated 100% sensitivity to Vancomycin and Ciprorofloxacin. The findings of this study suggest the users to disinfect their respective ear phones and not to exchange them as they may act as a potential source to transfer pathogenic and antibiotic resistant bacteria among the ear phone users. Stamford Journal of Microbiology, Vol.10 (1) 2020: 1-4


2018 ◽  
Vol 4 ◽  
pp. 49-54 ◽  
Author(s):  
Pramila Pathak ◽  
Nandalal Jaishi ◽  
Binod Kumar Yadav ◽  
Pradeep Kumar Shah

Objectives: This study was conducted to determine the prevalence of multi-drug resistance (MDR) along with Extended Spectrum β-lactamase (ESBL) and Metallo β-lactamase (MBL) producing gram negative bacterial isolates among the patients attending Shahid Gangalal National Heart Centre, Kathmandu, Nepal.Methods: This cross-sectional study was carried out from June to December; 2016. Altogether 977 clinical specimens were processed for analysis of bacteriological profile and the isolates were identified by culture, morphological and biochemical tests. Antibiotic susceptibility testing of the isolates was performed by Kirby Bauer disc diffusion methods following Clinical and Laboratories Standard Institute guideline and the isolates were tested for ESBL and MBL by combined disk method.Results: out of 977 clinical specimens, 254 (25.99%) were found to be gram negative bacterial isolates, among them Klebsiella pneumoniae 83 (32.67%) was the most predominant organism followed by E. coli 51 (20.07%), Pseudomonas aeruginosa 36 (14.17%), K. oxytoca 32 (12.59%), Proteus mirabilis 13 (5.11%) and P. vulgaris 13 (5.11%), Acinetobacter spp. 11 (4.33%), Citrobacter spp. 10 (3.93%) and Enterobacter spp. 5 (1.96%) respectively. 83 (32.67%) isolates were found to be MDR, 38(14.96%) were positive for ESBL while 19 (7.48%) were MBL producer.Conclusion: The determent drug resistance among ESBL and MBL producers, reflect the extensive use of antibiotics possessing difficulties in therapeutic potions in hospital setting which might be overcome by proper microbiological analysis of pathogenic isolates and judicious use of antibiotics for emergence of resistance strains.


2014 ◽  
Vol 6 (01) ◽  
pp. 007-013 ◽  
Author(s):  
Sridhar PN Rao ◽  
Prasad Subba Rama ◽  
Vishwanath Gurushanthappa ◽  
Radhakrishna Manipura ◽  
Krishna Srinivasan

ABSTRACT Background: There are sporadic reports on detection of extended-spectrum beta-lactamases (ESBL) producers from Karnataka; hence, this is a first multicentric study across Karnataka state to determine the prevalence of ESBL production among clinical isolates of Escherichia coli and Klebsiella pneumoniaei. Aims and objectives: To determine the prevalence of ESBL producing clinical isolates of E. coli and K. pneumoniae from five geographically distributed centers across Karnataka, to study the susceptibility of ESBL producing isolates to other beta-lactam and beta-lactam-beta-lactamase inhibitors and to demonstrate transferability of plasmids coding for ESBL phenotype. Materials and Methods: Two hundred isolates of E. coli and K. pneumoniae each were collected from each of the five centers (Bellary, Dharwad, Davangere, Kolar and Mangalore). They were screened for resistance to screening agents (ceftazidime, cefotaxime, ceftriaxone, aztreonam) and positive isolates were confirmed for ESBL production by test described by Clinical and Laboratory Standards Institute . Co-production of ESBL and AmpC beta-lactamase was identified by using amino-phenylboronic acid disk method. Susceptibility of ESBL producers to beta-lactam antibiotics and beta-lactamase inhibitors was performed. Transferability of plasmids was performed by conjugation experiment. Results: Overall prevalence of ESBL production among E. coli and K. pneumoniae across five centers of the state was 57.5%. ESBL production was found to be 61.4% among E. coli and 46.2% among K. pneumoniae. ESBL production was significantly more among E. coli than K. pneumoniae. Significant variations in distribution of ESBL across the state was observed among E. coli isolates, but not among K. pneumoniae isolates. All ESBL producers demonstrated minimum inhibitory concentration levels ≥2 μg/ml towards cefotaxime, ceftazidime and ceftriaxone. Conclusion: Overall prevalence of ESBL production among clinical isolates of E. coli and K. pneumoniae across Karnataka state was high. The prevalence of ESBL production was significantly higher with E. coli than K. pneumoniae isolates. Higher rates of resistance to ceftriaxone and cefotaxime than to ceftazidime suggests the possibility of presence of CTX-M type ESBLs. Of all the beta-lactam/beta-lactamase inhibitor combinations tested, cefepime-tazobactam demonstrated highest in-vitro activity against ESBL producers. There was no statistical difference in the transferability of plasmids among E. coli and K. pneumoniae.


2021 ◽  
Vol 38 (3) ◽  
pp. 301-304
Author(s):  
Zahra SADEGHI DEYLAMDEH ◽  
Abolfazl JAFARI SALES

Beta-lactamases are the most common cause of bacterial resistance to beta-lactam antibiotics. AmpC-type beta-lactamases hydrolyze cephalosporins, penicillins, and cephamycins. Therefore, the study aims was to determine antibiotic resistance and to investigate the presence of AmpC beta-lactamase gene in clinical strains of Escherichia coli isolated from hospitalized patients in Tabriz. In this cross-sectional descriptive study, 289 E. coli specimens were collected from clinical specimens. Disk diffusion method and combined disk method were used to determine the phenotype of extended spectrum β-Lactamase producing (ESBLs) strains. Then PCR was used to evaluate the presence of AmpC (FOX) beta-lactamase gene in the strains confirmed in phenotypic tests. Antibiotic resistance was also determined using disk diffusion by the Kibry-Bauer method. A total of 121 isolates were identified as generators of beta-lactamase genes. 72 (59.5 %) isolates producing ESBL and 49 (40.5 %) isolates were identified as AmpC generators. In the PCR test, 31 isolates contained the FOX gene. The highest resistance was related to the antibiotics amoxicillin (76.12%), ceftazidime (70.24%) and nalidixic acid (65.05%). The results indicate an increase in the prevalence of beta-lactamase genes and increased resistance to beta-lactam antibiotics, which can be the result of improper use of antibiotics and not using antibiotic susceptibility tests before starting treatment. Also, using phenotypic and molecular diagnostic methods such as PCR together can be very useful.


Author(s):  
Olga Lomovskaya ◽  
Debora Rubio-Aparicio ◽  
Kirk Nelson ◽  
Dongxu Sun ◽  
Ruslan Tsivkovski ◽  
...  

QPX7728 is an ultra-broad-spectrum beta-lactamase inhibitor with potent inhibition of key serine and metallo beta-lactamases. QPX7728 enhances the potency of multiple beta-lactams in beta-lactamase producing Enterobacterales and Acinetobacter spp. In this study we evaluated the in vitro activity of QPX7728 (8 μg/ml) combined with multiple beta-lactams against clinical isolates of Pseudomonas aeruginosa with varying beta-lactam resistance mechanisms. Seven-hundred-ninety clinical isolates were included in this study; 500 isolates, termed a “representative panel”, were selected to be representative the MIC distribution of meropenem (MEM), ceftazidime-avibactam (CAZ-AVI), and ceftolozane-tazobactam (TOL-TAZ) resistance for clinical isolates according to 2017 SENTRY surveillance data (representative panel). An additional 290 selected isolates (“challenge panel”), that were either non-susceptible to MEM or were resistant to TOL-TAZ or CAZ-AVI were also tested; 61 strains carried metallo beta-lactamases (MBLs), 211 strains were defective in the carbapenem porin OprD and 185 strains had the MexAB-OprM efflux pump overproduced based on a phenotypic test. Against the representative panel, susceptibility for all QPX7728/beta-lactam combinations was >90%. For the challenge panel, QPX-ceftolozane (TOL) was the most active combination (78.6% susceptible) followed by equipotent QPX-piperacillin (PIP) and QPX-cefepime (FEP), restoring susceptibility in 70.3% of strains (CLSI breakpoints for the beta-lactam compound alone). For MBL-negative strains, QPX-TOL and QPX-FEP restored the MIC values to susceptibility rates in ∼90% and ∼80% of strains, respectively, vs 68-70% for QPX-MEM and QPX-PIP and 63-65% for TOL-TAZ and CAZ-AVI. For MBL-positive strains, QPX-PIP restored the MIC to susceptibility values for ∼70% of strains vs 2-40% for other combinations. Increased efflux and impaired OprD had varying effect on QPX7728 combination depending on the partner beta-lactam tested. QPX7728 enhanced the potency of multiple beta-lactams against P. aeruginosa, with varying results according to the beta-lactamase production and other intrinsic resistance mechanisms.


2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Lalu Zulkifli ◽  
Dwi Soelistya Dyah Jekti ◽  
Samsul Bahri

The objective of this study was to isolate endophytic bacteria from bark of srikaya, analyzing antibacterial activity of endophytic bacteria in S. aureus, B. cereus and E. coli pathogenic bacteria, characterizing endophytic bacteria capable of inhibiting the growth of pathogenic bacteria and identification of endophytic bacteria able to inhibit the growth of pathogenic bacteria. Isolation of endophytic bacteria using TSA and NA media, bioassay on pathogen bacteria with concentration of 106 cells / ml with using Ø 6 mm wells and entering supernatant of 100 μl. Supernatant was obtained by growing endophytic bacteria in NB media shaken with shaker 150 cycles / min for 48 h at 32ᵒC then culture centrifuge at 5000 g for 30 min. Positive control using cyprofloxacin. Characterization is based on the nature of the colony, Gram paint, spore formation, and biochemical tests. The results of the study yielded 13 endophytic bacterial isolates and 4 endophytic isolates capable of inhibiting the growth of 8 pathogenic bacteria with sensitive criteria, 2 pathogenic bacteria with resistant criteria and 1 pathogen bacteria can not be inhibited its growth. Gram's paint results show that 4 endophytic isolates belong to Gram-positive, rod-shaped and spore forming cells. From the character possessed by the bacteria can be identified that the 4 bacteria endofit capable of inhibiting pathogenic bacteria are Bacillus brevis, Bacillus latesporus, Virgibacillus pantothenticus, and Bacillus circulansKeywords: Characterization, Endophytic Bacteria, Bark of Srikaya, Antibacterial


2020 ◽  
Vol 64 (6) ◽  
Author(s):  
Ruslan Tsivkovski ◽  
Maxim Totrov ◽  
Olga Lomovskaya

ABSTRACT QPX7728 is a new ultrabroad-spectrum inhibitor of serine and metallo-beta-lactamases (MBLs) from a class of cyclic boronates that gave rise to vaborbactam. The spectrum and mechanism of beta-lactamase inhibition by QPX7728 were assessed using purified enzymes from all molecular classes. QPX7728 inhibits class A extended-spectrum beta-lactamases (ESBLs) (50% inhibitory concentration [IC50] range, 1 to 3 nM) and carbapenemases such as KPC (IC50, 2.9 ± 0.4 nM) as well as class C P99 (IC50 of 22 ± 8 nM) with a potency that is comparable to or higher than recently FDA-approved beta-lactamase inhibitors (BLIs) avibactam, relebactam, and vaborbactam. Unlike those other BLIs, QPX7728 is also a potent inhibitor of class D carbapenemases such as OXA-48 from Enterobacteriaceae and OXA enzymes from Acinetobacter baumannii (OXA-23/24/58, IC50 range, 1 to 2 nM) as well as MBLs such as NDM-1 (IC50, 55 ± 25 nM), VIM-1 (IC50, 14 ± 4 nM), and IMP-1 (IC50, 610 ± 70 nM). Inhibition of serine enzymes by QPX7728 is associated with progressive inactivation with a high-efficiency k2/K ranging from 6.3 × 104 (for P99) to 9.9 × 105 M−1 s−1 (for OXA-23). This inhibition is reversible with variable stability of the QPX7728-beta-lactamase complexes with target residence time ranging from minutes to several hours: 5 to 20 min for OXA carbapenemases from A. baumannii, ∼50 min for OXA-48, and 2 to 3 h for KPC and CTX-M-15. QPX7728 inhibited all tested serine enzymes at a 1:1 molar ratio. Metallo-beta-lactamases NDM, VIM, and IMP were inhibited by a competitive mechanism with fast-on–fast-off kinetics, with Kis of 7.5 ± 2.1 nM, 32 ± 14 nM, and 240 ± 30 nM for VIM-1, NDM-1, and IMP-1, respectively. QPX7728’s ultrabroad spectrum of BLI inhibition combined with its high potency enables combinations with multiple different beta-lactam antibiotics.


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