The Changing Face of Bacterial Soft-Rot Diseases

2018 ◽  
Vol 56 (1) ◽  
pp. 269-288 ◽  
Author(s):  
Amy O. Charkowski
Keyword(s):  
Disease Management ◽  
Soft Rot ◽  
Diploid Potato ◽  
Bacterial Soft Rot ◽  
Foot Rot ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Storage Organs ◽  
Rot Disease ◽  
Over Time

Bacterial soft rot is a disease complex caused by multiple genera of gram-negative and gram-positive bacteria, with Dickeya and Pectobacterium being the most widely studied soft-rot bacterial pathogens. In addition to soft rot, these bacteria also cause blackleg of potato, foot rot of rice, and bleeding canker of pear. Multiple Dickeya and Pectobacterium species cause the same symptoms on potato, complicating epidemiology and disease resistance studies. The primary pathogen species present in potato-growing regions differs over time and space, further complicating disease management. Genomics technologies are providing new management possibilities, including improved detection and biocontrol methods that may finally allow effective disease management. The recent development of inbred diploid potato lines is also having a major impact on studying soft-rot pathogens because it is now possible to study soft-rot disease in model plant species that produce starchy vegetative storage organs. Together, these new discoveries have changed how we face diseases caused by these pathogens.

The epidemiology of central venous catheter-related bloodstream infection in our renal units is changing

2021 ◽  
pp. 112972982199022
Author(s):  
Salvatore Mandolfo ◽  
Adriano Anesi ◽  
Vanina Rognoni
Keyword(s):  
Burkholderia Cepacia ◽  
Present Report ◽  
Statistical Significance ◽  
Bloodstream Infections ◽  
Venous Catheter ◽  
Renal Unit ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Over Time

Recent reports have shown an increase in the rate of Gram-negative bacteremia in several settings, including catheter-related bloodstream infections (CRBSI). To analyze if the epidemiology of CRBSI is also changing in hemodialysis patients, we revisited the etiology of CRBSIs in our renal unit over 8 years. During the observed periods, 149 episodes of CRBSIs were reported and the CRBSI incidence rate, ranged between 0.67 and 0.82 episodes/1000 tCVC days. Of these 149 episodes, 84 (56.3%) were due to Gram-positive bacteria, 62 (41.6%) to Gram-negative bacteria, and 3 (2.1%) to polymicrobial flora, no episodes of fungi were found. There was a trend, but not statistically significative, increase over time in the number of Gram-negative CRBSIs among the total CRBSIs, rising from 37.8% in the first period to 41.2% in the second period and to 44.3% in the last period, with a parallel decrease in the percentage of Gram-positive CRBSIs (from 59.5% to 56.9% and subsequently to 54.1%). Between Gram-negative, we reported an intensification of CRBSI due to Enterobacterales, particularly Escherichia coli. Among the Gram-negative, we have isolated germs rarely reported in the literature, such as Burkholderia cepacia, Pantoea agglomerans, and Rhizobium radiobacter. Regarding Gram-positive bacteria, a triplicate incidence of Staphylococcus aureus was reported with MRSA accounting for 42% in the third period. Among the Gram-positive bacteria, we reported two episodes of Kocuria kristinae and two of Bacillus spp. Our data demonstrated that the epidemiology of CRBSI in the same center, will change over time and Gram-negative strains are an increasing cause of CRBSI. The limitation of the present report is that statistical significance has not been reached, probably due to the limited number of CRBSI. New bacteria, both Gram-negative and Gram-positive, are emerging. Collaboration with the Microbiology Department appears essential to an appropriate diagnosis.

scholarly journals Screening, Identification and Efficacy Evaluation of Antagonistic Bacteria for Biocontrol of Soft Rot Disease Caused by Dickeya zeae

2020 ◽  
Vol 8 (5) ◽  
pp. 697 ◽  
Author(s):  
Jieling Li ◽  
Ming Hu ◽  
Yang Xue ◽  
Xia Chen ◽  
Guangtao Lu ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Prevention And Control ◽  
Pathogenic Bacteria ◽  
Soft Rot ◽  
Antagonistic Bacteria ◽  
Bacterial Soft Rot ◽  
Soft Rot Disease ◽  
Wide Range ◽  
Rot Disease ◽  
And Control

Dickeya zeae is the causal agent of bacterial soft rot disease, with a wide range of hosts all over the world. At present, chemical agents, especially agricultural antibiotics, are commonly used in the prevention and control of bacterial soft rot, causing the emergence of resistant pathogens and therefore increasing the difficulty of disease prevention and control. This study aims to provide a safer and more effective biocontrol method for soft rot disease caused by D. zeae. The spot-on-lawn assay was used to screen antagonistic bacteria, and three strains including SC3, SC11 and 3-10 revealed strong antagonistic effects and were identified as Pseudomonas fluorescens, P. parafulva and Bacillus velezensis, respectively, using multi-locus sequence analysis (MLSA) based on the sequences of 16S rRNA and other housekeeping genes. In vitro antimicrobial activity showed that two Pseudomonas strains SC3 and SC11 were only antagonistic to some pathogenic bacteria, while strain 3-10 had broad-spectrum antimicrobial activity on both pathogenic bacteria and fungi. Evaluation of control efficacy in greenhouse trials showed that they all restrained the occurrence and development of soft rot disease caused by D. zeae MS2 or EC1. Among them, strain SC3 had the most impressive biocontrol efficacy on alleviating the soft rot symptoms on both monocotyledonous and dicotyledonous hosts, and strain 3-10 additionally reduced the occurrence of banana wilt disease caused by Fusarium oxysporum f. sp. cubensis. This is the first report of P. fluorescens, P. parafulva and B. velezensis as potential bio-reagents on controlling soft rot disease caused by D. zeae.

scholarly journals Microbiological Isolates and Antibiotic Susceptibilities in Cases of Posttraumatic Endophthalmitis: A 15-Year Review

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Chunhong Liu ◽  
Jian Ji ◽  
Zhujian Wang ◽  
Huiwen Chen ◽  
Wenjun Cao ◽  
...  
Keyword(s):  
Antibiotic Sensitivity ◽  
Coagulase Negative Staphylococci ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Fungal Isolates ◽  
Antibiotic Susceptibilities ◽  
Chi Squared ◽  
Posttraumatic Endophthalmitis ◽  
Over Time

Purpose. The objective of this study was to evaluate the microbiological spectrum and antibiotic susceptibilities of isolates in posttraumatic endophthalmitis over a 15-year period. Methods. A retrospective study of 3,163 posttraumatic endophthalmitis cases was conducted between July 2004 and July 2019. The outcome measures included the microbiological spectrum and antibiotic susceptibilities. Chi-squared tests were conducted to detect trends in changes in antibiotic sensitivity over the 15-year period. P values of <0.05 were considered statistically significant. Results. Of the 3,163 cases of posttraumatic endophthalmitis, 1,003 culture-positive isolates were identified. Among these, there were 848 (84.5%) Gram-positive isolates, 109 (10.9%) Gram-negative isolates, and 46 (4.6%) fungal isolates. The most common isolates were Staphylococcal species. There was a significant increase in the percentage of fungal isolates over the 15-year period (P=0.02). Gram-positive organisms showed the greatest level of susceptibility to vancomycin (99.6%). The susceptibilities of the 109 Gram-negative isolated organisms were as follows: levofloxacin (95.8%), meropenem (95.7%), ciprofloxacin (93.5%), tobramycin (90.8%), imipenem (88.9%), trimethoprim-sulfamethoxazole (TMP-SMX) (87.7%), ertapenem (80%), and ceftazidime (79.1%). The susceptibility of Gram-positive organisms to several antibiotics, including levofloxacin (P=0.004), ciprofloxacin (P<0.001), and chloramphenicol (P=0.001) decreased over time, whereas the susceptibility to TMP-SMX increased over time (P<0.001). The susceptibility of Gram-negative bacilli to ceftazidime decreased over time (P=0.03). Conclusions. Over the 15-year study period, most isolates were Gram-positive cocci, especially coagulase-negative staphylococci (CNS). Vancomycin seemed to be the most effective antibiotic for Gram-positive bacteria. Gram-negative bacteria appeared to be most susceptible to fluoroquinolones. A number of antibiotics showed an increasing trend of microbial resistance.

scholarly journals Original Article. In vitro evaluation of potato genotypes for resistance against bacterial soft rot (Pectobacterium carotovorum) – a new tool for studying disease resistance

2016 ◽  
Vol 57 (1) ◽  
pp. 1-8
Author(s):  
Sima Azadmanesh ◽  
Javad Mozafari ◽  
Nader Hasanzadeh ◽  
Cobra Moslemkhani
Keyword(s):  
Soft Rot ◽  
Bacterial Suspension ◽  
Post Inoculation ◽  
Pectobacterium Carotovorum ◽  
In Vitro Screening ◽  
Bacterial Soft Rot ◽  
Inoculation Techniques ◽  
Potato Collection ◽  
Rot Disease

Abstract In vitro screening techniques were used to evaluate 46 genotypes of Iranian potato collection for resistance to bacterial soft rot caused by Pectobacterium carotovorum subsp. carotovorum (Pcc). One month old in vitro rooted potato plantlets were inoculated by two inoculation techniques under in vitro conditions: 1) sterile toothpicks dipped into bacterial suspension and pressed into the crown of plantlets and 2) the freshly cut crown of plantlets were dipped into bacterial suspension of 108 cfu ∙ ml-1 for 10 min. Typical soft rot disease symptoms, including the percentage of wilted leaves were recorded on inoculated plantlets 3, 6, 9, 12 and 15 days post-inoculation. The potato genotypes which were examined responded differently to Pcc and varying levels of resistance were observed. Potato genotype AG showed the highest level of resistance. Results obtained from in vitro screening were then verified by classical tuber slice assay. The verifications were conducted using five representative cultivars: Milva, Ramus, Picaso, Marfona and Agria which responded similarly to both in vitro and classical evaluation systems. Similar results obtained from these tests indicated that the in vitro screening technique developed in this study could provide a simple and rapid whole plant assay in selecting resistant potato genotypes against bacterial soft rot.

scholarly journals First Report of Bacterial Soft Rot Disease on Mammillaria mystax Caused by Enterobacter cloacae subsp. dissolvens in Mexico

Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1536-1536
Author(s):  
Guadalupe Reyes-García ◽  
Santo Ángel Ortega-Acosta ◽  
Francisco Palemón-Alberto ◽  
Yanet Romero Ramírez ◽  
Jeiry Toribio-Jiménez ◽  
...  
Keyword(s):  
Enterobacter Cloacae ◽  
Soft Rot ◽  
Bacterial Soft Rot ◽  
First Report ◽  
Soft Rot Disease ◽  
Rot Disease

Characterization of Dickeya fangzhongdai causing bacterial soft rot disease on Dendrobium nobile in India

2020 ◽  
Vol 158 (3) ◽  
pp. 773-780
Author(s):  
A. Balamurugan ◽  
A. Kumar ◽  
K. Sakthivel ◽  
M. Ashajyothi ◽  
Kuleshwar Prasad Sahu ◽  
...  
Keyword(s):  
Soft Rot ◽  
Bacterial Soft Rot ◽  
Dendrobium Nobile ◽  
Soft Rot Disease ◽  
Rot Disease

scholarly journals Spectrum and Sensitivity of Bacterial Keratitis Isolates in Auckland

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
S. Marasini ◽  
S. Swift ◽  
S. J. Dean ◽  
S. E. Ormonde ◽  
J. P. Craig
Keyword(s):  
Public Hospital ◽  
Hospital Admissions ◽  
Antibiotic Sensitivity ◽  
Gram Negative Bacteria ◽  
Bacterial Keratitis ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Culture Positive ◽  
Over Time

Background.The bacteria isolated from severe cases of keratitis and their antibiotic sensitivity are recognised to vary geographically and over time.Objectives.To identify the most commonly isolated bacteria in keratitis cases admitted over a 24-month period to a public hospital in Auckland, New Zealand, and to investigatein vitrosensitivity to antibiotics.Methods.Hospital admissions for culture-proven bacterial keratitis between January 2013 and December 2014 were identified. Laboratory records of 89 culture positive cases were retrospectively reviewed and antibiotic sensitivity patterns compared with previous studies from other NZ centres.Results.From 126 positive cultures, 35 species were identified.Staphylococcuswas identified to be the most common isolate (38.2%), followed byPseudomonas(21.3%). Over the last decade, infection due toPseudomonasspecies, in the same setting, has increased (p≤0.05). Aminoglycosides, cefazolin, ceftazidime, erythromycin, tetracycline, and doxycycline were 100% effective against tested isolatesin vitro. Amoxicillin (41.6%), cefuroxime (33.3%), and chloramphenicol (94.7%) showed reduced efficacy against Gram-negative bacteria, whereas penicillin (51%) and ciprofloxacin (98.8%) showed reduced efficacy against Gram-positive bacteria.Conclusions.Despite a shift in the spectrum of bacterial keratitis isolates, antibiotic sensitivity patterns have generally remained stable and show comparability to results within the last decade from NZ centres.

scholarly journals Antimicrobial Peptide Resistance Genes in the Plant Pathogen Dickeya dadantii

2016 ◽  
Vol 82 (21) ◽  
pp. 6423-6430 ◽  
Author(s):  
Caroline Pandin ◽  
Martine Caroff ◽  
Guy Condemine
Keyword(s):  
Antimicrobial Peptides ◽  
Bacterial Resistance ◽  
Soft Rot ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Dickeya Dadantii ◽  
Gram Negative ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
New Genes

ABSTRACTModification of teichoic acid through the incorporation ofd-alanine confers resistance in Gram-positive bacteria to antimicrobial peptides (AMPs). This process involves the products of thedltXABCDgenes. These genes are widespread in Gram-positive bacteria, and they are also found in a few Gram-negative bacteria. Notably, these genes are present in all soft-rot enterobacteria (PectobacteriumandDickeya) whosedltDXBACoperons have been sequenced. We studied the function and regulation of these genes inDickeya dadantii.dltBexpression was induced in the presence of the AMP polymyxin. It was not regulated by PhoP, which controls the expression of some genes involved in AMP resistance, but was regulated by ArcA, which has been identified as an activator of genes involved in AMP resistance. However,arcAwas not the regulator responsible for polymyxin induction of these genes in this bacterium, which underlines the complexity of the mechanisms controlling AMP resistance inD. dadantii. Two other genes involved in resistance to AMPs have also been characterized,phoSandphoH.dltB,phoS,phoH, andarcAbut notdltDmutants were more sensitive to polymyxin than the wild-type strain. Decreased fitness of thedltB,phoS, andphoHmutants in chicory leaves indicates that their products are important for resistance to plant AMPs.IMPORTANCEGram-negative bacteria can modify their lipopolysaccharides (LPSs) to resist antimicrobial peptides (AMPs). Soft-rot enterobacteria (DickeyaandPectobacteriumspp.) possess homologues of thedltgenes in their genomes which, in Gram-positive bacteria, are involved in resistance to AMPs. In this study, we show that these genes confer resistance to AMPs, probably by modifying LPSs, and that they are required for the fitness of the bacteria during plant infection. Two other new genes involved in resistance were also analyzed. These results show that bacterial resistance to AMPs can occur in bacteria through many different mechanisms that need to be characterized.

scholarly journals 001 Establishment of Methods in Evaluating the Susceptibility of Chinese Cabbage (Brassica campestris spp.) to Soft Rot Disease by Erwinia

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 440-441
Author(s):  
Won Jun ◽  
Soo-Seong Lee ◽  
Jongkee Kim
Keyword(s):  
Chinese Cabbage ◽  
Large Scale ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Experimental Plant ◽  
Bacterial Soft Rot ◽  
Breeding Lines ◽  
Inoculation Methods ◽  
Soft Rot Disease ◽  
Rot Disease

Three inoculation methods, including cutting of a leaf, drenching, and point inoculation, were compared in an effort to screen the susceptibility of Chinese cabbage to soft rot disease caused by Erwinia carotovora subsp. carotovora. Three- to 4-week-old seedlings from 10 lines of cabbage with 16-h-old bacterial culture were routinely used. Inoculated seedlings were kept at 25.0 ± 10.0 °C for 48 h with saturated water vapor using a plastic tunnel in a greenhouse. Sixty-day-old mature plants were produced and inoculated in a greenhouse. Severity of symptoms, which were observed from percentage of plant infected was scored as from 1 to 9, representing resistant to susceptible, respectively. The correlation between seedlings and mature plants from ten lines was evaluated among the three different inoculation methods. Point inoculation gave the most significant correlation (r = 0.843, P < 0.05) between seedlings and mature plants. A good correlation was also observed between point inoculation of seedlings and drenching of mature plants (r = 0.609, P < 0.05). Cutting of a leaf of seedlings was also correlated with point inoculation of mature plants (r = 0.609, P < 0.05). This method provides the advantage of being able to keep the experimental plant alive, as only one leaf is detached. The point inoculation method is simple and relatively sensitive, so it could be used for large-scale screening for this bacterial soft rot disease. From three different evaluation assays, it was concluded that the breeding lines, C3-28, C3-29 from Cornell Univ. (Geneva, N.Y.) and the cultivar Kweonsim319 were relatively resistant to bacterial soft rot, while the Cornell breeding line CC-25 and the `Rang-no' cultivar were relatively susceptible.

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