scholarly journals Relationship between Virulence and Resistance among Gram-Negative Bacteria

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 719
Author(s):  
Virginio Cepas ◽  
Sara M. Soto
Keyword(s):  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant ◽  
Great Capacity ◽  
Gram Negative ◽  
Points Of View ◽  
The Relationship ◽  
Selection Of

Bacteria present in the human body are innocuous, providing beneficial functions, some of which are necessary for correct body function. However, other bacteria are able to colonize, invade, and cause damage to different tissues, and these are categorised as pathogens. These pathogenic bacteria possess several factors that enable them to be more virulent and cause infection. Bacteria have a great capacity to adapt to different niches and environmental conditions (presence of antibiotics, iron depletion, etc.). Antibiotic pressure has favoured the emergence and spread of antibiotic-resistant bacteria worldwide. Several studies have reported the presence of a relationship (both positive and negative, and both direct and indirect) between antimicrobial resistance and virulence among bacterial pathogens. This review studies the relationship among the most important Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) taking into account two points of view: (i) the effect the acquisition of resistance has on virulence, and (ii) co-selection of resistance and virulence. The relationship between resistance and virulence among bacteria depends on the bacterial species, the specific mechanisms of resistance and virulence, the ecological niche, and the host.

scholarly journals Antibiotic Resistance and Virulence Profiles of Gram-Negative Bacteria Isolated from Loggerhead Sea Turtles (Caretta Caretta) of the Island of Maio, Cape Verde

2021 ◽  
Author(s):  
Matilde Costa Fernandes ◽  
Miguel L. Grilo ◽  
Eva Cunha ◽  
Carla Carneiro ◽  
Luís Tavares ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Pathogenic Bacteria ◽  
Sea Turtles ◽  
Caretta Caretta ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant Bacteria ◽  
Loggerhead Sea Turtles ◽  
Antibiotic Resistant ◽  
Gram Negative

Abstract Background: Several studies detected high levels of antibiotic-resistance in loggerhead sea turtles (Caretta caretta) and pointed this species as prime reservoirs of antibiotic-resistant bacteria and carriers of potentially pathogenic bacteria. This study aimed to characterize, for the first time, the Gram-negative aerobic microbiota of the Cape Verdean loggerhead subpopulation. Cloacal, oral and egg content swab samples from 33 nesting loggerheads (n = 99) of the Island of Maio were analysed regarding the presence of Gram-negative bacteria and their antibiotic resistance and virulence profiles. Results: Shewanella putrefaciens (27.78%), Morganella morganii (22.22%) and Vibrio alginolyticus (22.22%) were the most prevalent species isolated from the animals under study. A low incidence of antibiotic-resistant bacteria (26%) was detected, and no multidrug-resistant isolates were identified. Non-Enterobacteriaceae isolates presented the most complex virulence profiles, revealing the ability to produce hemolysins (100%), DNases (89%), lipases (79%), proteases (53%), lecithinases (21%), gelatinases (16%), and also biofilms (74%). Moreover, higher virulence indices were obtained for turtles with high parasite intensities compared with apparently healthy animals, and a positive correlation between antibiotic resistance and virulence was observed. Conclusions: Results suggest that this loggerhead population may be less exposed to antimicrobial compounds, probably due to the low anthropogenic impact observed in both their nesting (the Island of Maio) and foraging sites. Nevertheless, the presence of potentially pathogenic bacteria expressing virulence factors may threat both sea turtles’ and humans’ health.

scholarly journals Developing Cyclic Peptomers as Broad-Spectrum Gram-negative Bacterial Type III Secretion System Inhibitors

2021 ◽  
Author(s):  
Hanh N. Lam ◽  
Tannia Lau ◽  
Adam Lentz ◽  
Jessica Sherry ◽  
Alejandro Cabrera-Cortez ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Pathogenic Bacteria ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Type Iii ◽  
Twin Arginine Translocation

Antibiotic resistant bacteria are an emerging global health threat. New antimicrobials are urgently needed. The injectisome type III secretion system (T3SS), required by dozens of Gram-negative bacteria for virulence but largely absent from non-pathogenic bacteria, is an attractive antimicrobial target. We previously identified synthetic cyclic peptomers, inspired by the natural product phepropeptin D, that inhibit protein secretion through the Yersinia Ysc and Pseudomonas aeruginosa Psc T3SSs, but do not inhibit bacterial growth. Here we describe identification of an isomer, 4EpDN, that is two-fold more potent (IC50 of 4 μM) than its parental compound. Furthermore, 4EpDN inhibited the Yersinia Ysa and the Salmonella SPI-1 T3SSs, suggesting that this cyclic peptomer has broad efficacy against evolutionarily distant injectisome T3SSs. Indeed, 4EpDN strongly inhibited intracellular growth of Chlamydia trachomatis in HeLa cells, which requires the T3SS. 4EpDN did not inhibit the unrelated Twin arginine translocation (Tat) system, nor did it impact T3SS gene transcription. Moreover, although the injectisome and flagellar T3SSs are evolutionarily and structurally related, the 4EpDN cyclic peptomer did not inhibit secretion of substrates through the Salmonella flagellar T3SS, indicating that cyclic peptomers broadly but specifically target the injestisome T3SS. 4EpDN reduced the number of T3SS needles detected on the surface of Y. pseudotuberculosis as detected by microscopy. Collectively, these data suggest that cyclic peptomers specifically inhibit the injectisome T3SS from a variety of Gram-negative bacteria, possibly by preventing complete T3SS assembly.

scholarly journals Antibiotic Resistance of Gram-Negative Bacteria from Wild Captured Loggerhead Sea Turtles

Antibiotics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 162 ◽  
Author(s):  
Monica Francesca Blasi ◽  
Luciana Migliore ◽  
Daniela Mattei ◽  
Alice Rotini ◽  
Maria Cristina Thaller ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Sea Turtles ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Marine Animals ◽  
Loggerhead Sea Turtles ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Marine Habitats ◽  
Resistant Strains

Sea turtles have been proposed as health indicators of marine habitats and carriers of antibiotic-resistant bacterial strains, for their longevity and migratory lifestyle. Up to now, a few studies evaluated the antibacterial resistant flora of Mediterranean loggerhead sea turtles (Caretta caretta) and most of them were carried out on stranded or recovered animals. In this study, the isolation and the antibiotic resistance profile of 90 Gram negative bacteria from cloacal swabs of 33 Mediterranean wild captured loggerhead sea turtles are described. Among sea turtles found in their foraging sites, 23 were in good health and 10 needed recovery for different health problems (hereafter named weak). Isolated cloacal bacteria belonged mainly to Enterobacteriaceae (59%), Shewanellaceae (31%) and Vibrionaceae families (5%). Although slight differences in the bacterial composition, healthy and weak sea turtles shared antibiotic-resistant strains. In total, 74 strains were endowed with one or multi resistance (up to five different drugs) phenotypes, mainly towards ampicillin (~70%) or sulfamethoxazole/trimethoprim (more than 30%). Hence, our results confirmed the presence of antibiotic-resistant strains also in healthy marine animals and the role of the loggerhead sea turtles in spreading antibiotic-resistant bacteria.

scholarly journals Antibiotic-Resistant Gram-Negative Bacteria in Birds From the Brazilian Atlantic Forest

The Condor ◽  
2003 ◽  
Vol 105 (2) ◽  
pp. 358-361 ◽  
Author(s):  
Andréa M. A. Nascimento ◽  
Luciana Cursino ◽  
Higgor Gonçalves-Dornelas ◽  
Andrea Reis ◽  
Edmar Chartone-Souza ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Kanamycin Resistance ◽  
Minas Gerais ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Brazilian Atlantic Forest ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Resistant Phenotype ◽  
Animal Farms

Abstract We evaluated the antibiotic resistance of bacteria isolated from cloacal swabs of wild birds collected with mist nets in the Jequitinhonha river valley, in the state of Minas Gerais, Brazil. A total of 191 isolates from 19 individuals of 16 species was obtained and tested for resistance to five antibiotics. At Salto da Divisa 97% of the isolates exhibited a resistant phenotype, and resistance to more than one antibiotic was frequent (71%). At Jequitinhonha 36% of isolates were resistant, but 94% showed resistance to only one antibiotic. Of the five antibiotics tested, resistance to ampicillin was most frequent (in both areas), whereas kanamycin resistance was found in only one isolate. The data here obtained and other data reported in the literature show that the general premise that antibiotic-resistant bacteria arise primarily in hospitals or animal farms should be reconsidered. Bactérias Gram-Negativas Resistentes a Antibióticos em Aves da Mata Atlântica Brasileira Resumo. Avaliamos a resistência a antibióticos de bactérias isoladas por swab cloacal em aves selvagens capturadas com redes de neblina em duas regiões do Vale do Rio Jequitinhonha, Minas Gerais, Brasil. Foram obtidos 191 isolados de 19 indivíduos de 16 espécies e foi testada a resistência desses isolados a cinco antibióticos. Em Salto da Divisa, 97% dos isolados exibiram fenótipo resistente e foi freqüente (71%) a resistência a mais de um antibiótico. Em Jequitinhonha, 36% dos isolados exibiram fenótipo resistente, dos quais 94% apresentaram resistência a apenas um antibiótico. Em ambas as áreas, a maioria dos isolados apresentou resistência à ampicilina, enquanto somente um único isolado foi resistente à canamicina. Os dados aqui obtidos e outros relatados na literatura mostram que a premissa geral de que bactérias resistentes a antibióticos surgem principalmente em hospitais ou fazendas de animais deve ser reconsiderada.

scholarly journals Molecular Characterization of Zinc (Zn) Resistant Bacteria in Banger River, Pekalongan, Indonesia

2018 ◽  
Vol 10 (3) ◽  
pp. 622-628
Author(s):  
Fitri Arum Sasi ◽  
Hermin Pancasakti Kusumaningrum ◽  
Anto Budiharjo
Keyword(s):  
Bacterial Species ◽  
Selective Medium ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Indigenous Bacteria ◽  
Gram Positive Bacteria ◽  
Sequences Analysis

Indigenous bacteria are able to remove the metals contamination in environment. This study aimed to assess the resistance of bacterial species to Zinc (Zn) in Banger River, Pekalongan City. The bacteria from three different parts of Banger River were isolated and inoculated in Zn-selective medium. Then, molecular identification to determine the bacteria species was conducted using polymerase chain reaction (PCR) by applying forward-reverse 16SrRNA gene primers. The sequences analysis was conducted using MUSCLE and MEGA6. There were seven dominant species that possibly resistant to Zn. Approximately, every isolate could reach more than 95 % from 2000 ppm of Zn in the medium. The higher absorption of Zn was found in Z5 isolate. The seven bacteria species were clustered into nine genera i.e. Klebsiela, Xenorhabdus, Cronobacter, Enterobacter, Escherichia, Shigella and Sporomusa known as Gram Negative bacteria and Clostridium and Bacillus as Gram Positive bacteria. In Gram Positive bacteria, especially Bacillus sp, carboxyl group in peptidoglycan play a role as metal binder. In Gram-negative bacteria, lipopolysaccharide (LPS) which is highly anionic component on the outer membrane, able to catch the Zn. Besides that, Enterobacter activates endogen antioxidants such as glutathione peroxidase (GSHPx), glutathione reductase (GR), catalase (CAT) and superoxide dismutase (SOD). The research found there was possible seven novel indigenous bacteria species in Banger that able to remove Zn from the sediment extremely. This finding can be developed as an eco-friendly approach to reduce metals pollution using local microorganisms.

Bacteria rapidly colonize and modulate healing of gastric ulcers in rats

1998 ◽  
Vol 275 (3) ◽  
pp. G425-G432 ◽  
Author(s):  
Susan N. Elliott ◽  
André Buret ◽  
Webb McKnight ◽  
Mark J. S. Miller ◽  
John L. Wallace
Keyword(s):  
Ulcer Healing ◽  
Bacterial Colonization ◽  
Healing Process ◽  
Gastric Ulcers ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
E Coli ◽  
Beneficial Effects ◽  
The Relationship

The stomach is generally regarded as an environment that is not conducive to bacterial colonization. In this study, we examined the possibility that this changes significantly when an ulcer has formed and that colonization of ulcers interferes with the normal healing process. Gastric ulcers were induced by serosal application of acetic acid. The relationship between ulcer healing and bacterial colonization was examined. The effects of antibiotics, induction of Lactobacilluscolonization, and selective colonization with an antibiotic resistant strain of Escherichia coli on ulcer healing were examined. Within 6–12 h of their induction, gastric ulcers were colonized by a variety of bacteria, with gram-negative bacteria predominating. Suppression of colonization with antibiotics resulted in marked acceleration of healing. Induction of Lactobacillus colonization also accelerated ulcer healing. The beneficial effects of antibiotics were reversed through selective colonization with antibiotic-resistant E. coli. Bacterial colonization occurred irrespective of the method used to induce the ulcer. This study demonstrates that colonization of gastric ulcers in rats occurs rapidly and significantly impairs ulcer healing. This effect appeared to be primarily attributable to gram-negative bacteria.

scholarly journals Synergism between Outer Membrane Proteins and Antimicrobials

2011 ◽  
Vol 55 (5) ◽  
pp. 2206-2211 ◽  
Author(s):  
P. Veiga-Crespo ◽  
E. Fusté ◽  
T. Vinuesa ◽  
M. Viñas ◽  
T. G. Villa
Keyword(s):  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Bactericidal Effect ◽  
Resistant Bacteria ◽  
Logarithmic Phase ◽  
Permeability Barrier ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Gram Negative

ABSTRACTAntibiotic-resistant bacteria are becoming one of the most important problems in health care because of the number of resistant strains and the paucity of new effective antimicrobials. Since antibiotic-resistant bacteria will continue to increase, it is necessary to look for new alternative strategies to fight against them. It is generally accepted that Gram-negative bacteria are intrinsically less susceptible than Gram-positive bacteria to antimicrobials. The main reason is that Gram-negative bacteria are surrounded by a permeability barrier known as the outer membrane (OM). Hydrophilic solutes most often cross the OM through water-filled channels formed by a particular family of proteins known as porins. This work explores the possibility of using exogenous porins to lower the required amounts of antibiotics (ampicillin, ciprofloxacin, cefotaxime, clindamycin, erythromycin, and tetracycline). Porins had a bactericidal effect onEscherichia colicultures, mainly in the logarithmic phase of growth, when combined with low antibiotic concentrations. The use of different antibiotic-porin mixtures showed a bactericidal effect greater than those of antibiotics and porins when used separately. It was possible to observe different behaviors according to the antibiotic type used.

scholarly journals Lysophosphatidylcholine Potentiates Antibacterial Activity of Polymyxin B

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
Jitender Yadav ◽  
Sana Ismaeel ◽  
Ayub Qadri
Keyword(s):  
Antibacterial Activity ◽  
Polymyxin B ◽  
Resistant Bacteria ◽  
Bacterial Membrane ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Drug Resistant Bacteria

ABSTRACT Polymyxin B, used to treat infections caused by antibiotic-resistant Gram-negative bacteria, produces nephrotoxicity at its current dosage. We show that a combination of nonbactericidal concentration of this drug and lysophosphatidylcholine (LPC) potently inhibits growth of Salmonella and at least two other Gram-negative bacteria in vitro. This combination makes bacterial membrane porous and causes degradation of DnaK, the regulator of protein folding. Polymyxin B-LPC combination may be an effective and safer regimen against drug-resistant bacteria.

scholarly journals Occurrence of Multiple Antibiotic Resistant Bacteria in Aquatic Environments in Central Minnesota

2015 ◽  
Vol 12 (3) ◽  
Author(s):  
Megan Bollin ◽  
Ellen Jensen ◽  
David Mitchell
Keyword(s):  
Aquatic Ecosystems ◽  
Resistant Bacteria ◽  
Aquatic Environments ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Antibiotic Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Density Values ◽  
Resistance Coefficients

The purpose of this study was to investigate the possibility that antibiotic resistant bacteria could be isolated and identified in aquatic ecosystems in the lakes on the campus of Saint John’s University and the nearby Sauk and Watab Rivers. A total of 125 isolates were collected. Seventy-nine percent of the isolates were gram negative rods. Twenty-six isolates that were resistant to seven or more antibiotics were selected for further investigation. The 26 isolates were all gram negative and members of seven different genera with Flavobacterium and Acinetobacter being the most common. Resistance coefficients were calculated based on optical density values relative to cells grown without antibiotics. Multi-drug resistant, gram negative bacteria were shown to be common in aquatic environments in central Minnesota.

scholarly journals Association between the rate of fluoroquinolones-resistant Gram-negative bacteria and antibiotic consumption from China based on 145 tertiary hospitals data in 2014

2019 ◽  
Author(s):  
Ping Yang ◽  
Yunbo Chen ◽  
Saiping Jiang ◽  
Ping Shen ◽  
Xiaoyang Lu ◽  
...  
Keyword(s):  
Antibiotic Consumption ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Annual Consumption ◽  
Tertiary Hospitals ◽  
The Relationship ◽  
Third Generation Cephalosporins ◽  
Consumption Intensity

Abstract This study aimed to investigate the relationship between the rate of fluoroquinolones-resistant (FQR) gram-negative bacteria and antibiotic consumption intensity in 145 tertiary hospitals from China in 2014.Methods A retrospective study using national surveillance data from 2014 was conducted. Data on the annual consumption of each antibiotic, and the rate of FQR gram-negative bacteria, were collected from each participating hospital, and the correlation between antibiotic consumption and FQR rate was simultaneously investigated.Results The overall antibiotic consumption intensity among the hospitals varied between 23.93 and 115.39 defined daily dosages (DDDs) per 100 patient-days (median, 46.30 DDDs per 100 patient-days). Cephalosporins were the most commonly prescribed antibiotics, followed by fluoroquinolones, penicillins, and carbapenems, and the rate of FQR gram-negative bacteria from each hospital varied. The correlation analysis showed significantly relationship between the percentage of FQR E. coli and the consumption of FQs consumption (r=0.308, p<0.01) and levofloxacin (r=0.252, p<0.01). For FQR K. pneumoniae, not only FQs (r=0.291, p<0.01) and levofloxacin (r=0.260, p<0.01) use but also carbapenems (r=0.242, p<0.01) and overall antibiotics (r=0.247, p<0.01) use showed significant correlation. A strong correlation was observed between the resistant proportion of FQR P. aeruginosa and the consumption of all antibiotics (r=0.260, p<0.01), FQs (r=0.319, p<0.01) and levofloxacin (r=0.377, p<0.01). The percentage of levofloxacin-resistant A. baumannii was significantly correlated with the consumption of all antibiotics (r=0.282, p<0.01), third-generation cephalosporins excluding combinations with beta-lactamase inhibitors (r=0.246, p<0.01), FQs (r=0.254, p<0.01) and levofloxacin (r=0.336, p<0.01). However, the correlation of the ciprofloxacin-resistant A. baumannii and the antibiotics consumption was not found.Conclusions A significant relationship was demonstrated between the antibiotic consumption and the rates of FQR gram-negative bacteria. As unreasonable antibiotics usage remains crucial in the proceeding of resistant bacteria selection, our study could greatly promote the avoidance of unnecessary antibiotic usage.

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