Theoretical and practical study of the cefoxitin‐Escherichia coli PBP5 complex interaction by molecular dynamics to obtain computational prototype of antimicrobial susceptibility to Gram negative bacteria

2020 ◽  
Vol 96 (4) ◽  
pp. 1095-1102
Author(s):  
Thaís Boulhosa Barros da Silva ◽  
Marta Chagas Monteiro ◽  
Rosivaldo dos Santos Borges ◽  
Tainá Guimarães Barros ◽  
Agnaldo da Silva Carneiro ◽  
...  
2020 ◽  
Vol 21 ◽  
Author(s):  
Karine Louise Calaça ◽  
Renato Clini Cervi ◽  
Silvânia Andrade Reis ◽  
Iolanda Aparecida Nunes ◽  
Valéria de Sá Jayme ◽  
...  

Abstract Captive Psittaciformes may harbor Gram-negative bacteria in their digestive tract, mainly due to poor hygienic conditions and confinement. The present study was carried out with the objective of isolating and identifying Escherichia coli in samples collected from Psittaciformes cages in 50 commercial establishments in the metropolitan region of Goiania, with subsequent antimicrobial susceptibility testing and detection of virulence genes. A total of 141 samples of excreta and swab samples from feeders and water bowls were collected, totaling 423 samples. Escherichia coli was isolated from 9.7% (41/423) samples: 12% (17/141) in excreta, 8.5% (12/141) in feed, and 8.5% (12 /141) in waterers. To determine the susceptibility profile of E. coli isolates, resistance to ciprofloxacin 4.9% (2/41), gentamicin 17.0% (7/41), doxycycline 34.1% (14/41), florfenicol 34.1% (14/41), trimethoprim 39.0% (16/41), tetracycline 41.5% (17/41), enrofloxacin 43.9% (18/41), amoxicillin 48.8% (20/41), neomycin 61.0% (25/41), and sulfonamide 90.2% (37/41) was determined. In 20 isolates, resistance was determined at 4 or more antimicrobials, seven of excreta (7/17), five of feed (5/12), and eight of waterers (8/12). One of the isolates from the waterers showed resistance to all antimicrobials. The iss gene was detected in three isolates, the tsh gene in three, the papC gene in two, traT and eae genes were not detected. In this study, it can be concluded that Psittaciformes commercialized as pet are carry E. coli isolates resistant to most commonly used antimicrobials, mainly sulfonamides and neomycin, besides having virulence and serum resistance genes, which highlights the possibility of the to cause disease in humans.


2006 ◽  
Vol 50 (1) ◽  
pp. 374-378 ◽  
Author(s):  
Thomas K. W. Ling ◽  
Jianhui Xiong ◽  
Yunsong Yu ◽  
Ching Ching Lee ◽  
Huifen Ye ◽  
...  

ABSTRACT A survey of 2,099 gram-negative bacilli from community infections at seven centers in the People's Republic of China is reported. The rates of resistance of 1,615 isolates of the family Enterobacteriaceae were as follows: 40.8% for ciprofloxacin, 32.2% for gentamicin, 0% for imipenem or ertapenem, and 14.7% for cefotaxime. The rates of extended-spectrum β-lactamase production were 16% for Escherichia coli and 17% for Klebsiella.


2013 ◽  
Vol 141 (11-12) ◽  
pp. 775-779 ◽  
Author(s):  
Tatjana Markovic ◽  
Ljiljana Jeinic ◽  
Aleksandra Smitran ◽  
Miroslav Petkovic

Introduction. In Gram-negative bacteria, the production of beta-lactamases is the most important mechanism of resistance to beta-lactam antibiotics. In the Banja Luka region, there were no extensive researches on the prevalence and antimicrobial resistance of the extended-spectrum beta-lactamase (ESBL) producing Escherichia coli (E. coli) isolates. Objective. The aim of the present study was to determine the presence of ESBL producing E. coli isolates as the cause of the urinary tract infections in outpatients, the distribution of these ESBL isolates according to age and gender of patients and their susceptibility to antimicrobials. Methods. Urine specimens obtained from outpatients were cultured on chromogenic CPS-ID3 media. All plates showing significant (>105 cfu/ml) growth of E. coli in pure culture were further processed. Antimicrobial susceptibility testing was performed on VITEK TWO Compact using AST-GN27 cards for testing Gram negative bacteria and detection of ESBL producers. Results. Out of 2,195 isolates, 177 (8.1%) were ESBL producers. Ninety-two isolates were obtained from female patients (5% of E. coli isolated from women) and 85 isolates from male patients (23% of E. coli isolated from men). High percentage of ESBL isolates was detected in the infant age group under one year (36.7%) and in the age group over 60 years (28.8%). All ESBL isolates were susceptible to imipenem and resistant to ampicillin, piperacillin, cefazolin, cefotaxime, ceftazidime and cefepime. There was a significant resistance to amikacin (79.1%), gentamicin (76.8%), amoxicillin/clavulanate (54.8%) and trimethoprim/sulphamethoxazole (45.8%). Resistance to nutrofurantoin was 13.6%. Conclusion. This study has demonstrated the presence of ESBL producing E. coli urinary isolates in outpatients, and their extensive susceptibility to imipenem and nitrofurantoin.


Author(s):  
Saad Alhumaid ◽  
Abbas Al Mutair ◽  
Zainab Al Alawi ◽  
Ahmad J. Alzahrani ◽  
Mansour Tobaiqy ◽  
...  

Abstract Background Studying time-related changes in susceptible pathogens causing healthcare-associated infections (HAIs) is vital in improving local antimicrobial and infection control practices. Objectives Describe susceptibility patterns to several antimicrobials in gram-positive and gram-negative pathogens isolated from patients causing HAIs at three private tertiary care hospitals in Saudi Arabia over a 5-year period. Methods Data on trends of antimicrobial susceptibility among bacteria causing HAIs events in children and adults at three tertiary private hospitals located in Riyadh and Qassim, Saudi Arabia, were collected retrospectively between 2015 and 2019 using the surveillance data datasets. Results Over a 5-year period, 38,624 pathogens caused 17,539 HAI events in 17,566 patients. About 9450 (53.8%) of patients who suffered HAIs were females and the average age was 41.7 ± 14.3 years (78.1% were adults and 21.9% were children). Gram-negative pathogens were 2.3-times more likely to cause HAIs compared to gram-positive bacteria (71.9% vs. 28.1%). The ranking of causative pathogens in decreasing order was: Escherichia coli (38%), Klebsiella species (15.1%), and Staphylococcus aureus (12.6%). Gram-positive isolates were mostly susceptible to linezolid (91.8%) whereas they were resistant to ampicillin (52.6%), cefoxitin (54.2%), and doxycycline (55.9%). Gram-negative isolates were mostly sensitive to tigecycline (95%) whereas they were resistant to cefotaxime (49.5%) and cefixime (59.6%). During the 5 years, there were relatively stable susceptibility patterns to all tested antimicrobials, except for cefotaxime which shown a susceptibility reduction by 41.4%, among Escherichia coli and Klebsiella species. An increase in the susceptibility of Acinetobacter and Enterobacter and Citrobacter species to all studied antimicrobials was observed except for colistin that had a slight sensitivity reduction in 2019 by 4.3% against Acinetobacter species. However, we noted reduced sensitivity of MRSA, CoNS and Enterococcus species to gentamicin; and increased resistance of MRSA to linezolid and vancomycin. Conclusion The observed increase in susceptibility of gram-positive and gram-negative bacteria to studied antimicrobials is important; however, reduced sensitivity of MRSA, CoNS and Enterococcus species to gentamicin; and increased resistance of MRSA to linezolid and vancomycin is a serious threat and calls for effective antimicrobial stewardship programs.


Author(s):  
Rubal C Das ◽  
Rajib Banik ◽  
Robiul Hasan Bhuiyan ◽  
Md Golam Kabir

Macrophomina phaseolina is one of the pathogenic organisms of gummosis disease of orange tree (Citrus reticulata). The pathogen was identified from the observation of their colony size, shape, colour, mycelium, conidiophore, conidia, hyaline, spore, and appressoria in the PDA culture. The crude chloroform extracts from the organism showed antibacterial activity against a number of Gram positive and Gram-negative bacteria. The crude chloroform extract also showed promising antifungal activity against three species of the genus Aspergillus. The minimum inhibitory concentration (MIC) of the crude chloroform extract from M. phaseolina against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Shigella sonnie were 128 ?gm, 256 ?gm, 128 ?gm and 64 ?gm/ml respectively. The LD50 (lethal dose) values of the cytotoxicity assay over brine shrimp of the crude chloroform extract from M. phaseolina was found to be 51.79 ?gm/ml. DOI: http://dx.doi.org/10.3329/cujbs.v5i1.13378 The Chittagong Univ. J. B. Sci.,Vol. 5(1 &2):125-133, 2010


Author(s):  
Gemedo Misha ◽  
Legese Chelkeba ◽  
Tsegaye Melaku

Abstract Background Globally, surgical site infections are the most reported healthcare-associated infection and common surgical complication. In developing countries such as Ethiopia, there is a paucity of published reports on the microbiologic profile and resistance patterns of an isolates. Objective This study aimed at assessing the bacterial profile and antimicrobial susceptibility patterns of isolates among patients diagnosed with surgical site infection at Jimma Medical Center in Ethiopia. Methods A prospective cohort study was employed among adult patients who underwent either elective or emergency surgical procedures. All the eligible patients were followed for 30 days for the occurrence of surgical site infection (SSI). From those who developed SSI, infected wound specimens were collected and studied bacteriologically. Results Of 251 study participants, 126 (50.2%) of them were females. The mean ± SD age of the patients was 38 ± 16.30 years. The overall postoperative surgical site infection rate was 21.1% and of these 71.7% (38/53) were culture positive. On gram stain analysis, 78% of them were Gram-negative, 11.5% were Gram-positive and 10.5% were a mixture of two microbial growths. Escherichia coli accounted for (21.43%), followed by Pseudomonas aeruginosa (19.05%), Proteus species (spp.) 14.29%), Staphylococcus aureus (11.90%), Klebsiella species (11.90%), Citrobacter spp. (9.5%), streptococcal spp. (7.14%), Coagulase-negative S. aureus (CoNS) (2.38%) Conclusion Gram-negative bacteria were the most dominant isolates from surgical sites in the study area. Among the Gram-negative bacilli, Escherichia coli were the most common bacteria causing surgical site infection. As there is high antibiotic resistance observed in the current study, it is necessary for routine microbial analysis of samples and their antibiogram.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tessa B. Moyer ◽  
Ashleigh L. Purvis ◽  
Andrew J. Wommack ◽  
Leslie M. Hicks

Abstract Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.


2021 ◽  
Vol 22 (10) ◽  
pp. 5328
Author(s):  
Miao Ma ◽  
Margaux Lustig ◽  
Michèle Salem ◽  
Dominique Mengin-Lecreulx ◽  
Gilles Phan ◽  
...  

One of the major families of membrane proteins found in prokaryote genome corresponds to the transporters. Among them, the resistance-nodulation-cell division (RND) transporters are highly studied, as being responsible for one of the most problematic mechanisms used by bacteria to resist to antibiotics, i.e., the active efflux of drugs. In Gram-negative bacteria, these proteins are inserted in the inner membrane and form a tripartite assembly with an outer membrane factor and a periplasmic linker in order to cross the two membranes to expulse molecules outside of the cell. A lot of information has been collected to understand the functional mechanism of these pumps, especially with AcrAB-TolC from Escherichia coli, but one missing piece from all the suggested models is the role of peptidoglycan in the assembly. Here, by pull-down experiments with purified peptidoglycans, we precise the MexAB-OprM interaction with the peptidoglycan from Escherichia coli and Pseudomonas aeruginosa, highlighting a role of the peptidoglycan in stabilizing the MexA-OprM complex and also differences between the two Gram-negative bacteria peptidoglycans.


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