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1.
Ann Ital Chir ; 93: 377-384, 2022.
Article in English | MEDLINE | ID: mdl-36155937

ABSTRACT

INTRODUCTION: Inguinal hernia is one of the most common surgical diseases in the world. Today, this disease is treated by surgical technique only. Among the late complications after surgery, the most frequent is the appearance of chronic post-operative pain after surgical treatment. The incidence of this complication is about 28% of patients undergoing hernioplasty suffering a varying degree of chronic pain, severe enough to interfere with normal daily activities. OBJECTIVES: In this study we evaluated the onset of the neuropathic pain as a complication of inguinal prosthetic hernioplasty surgery. METHODS: This is a prospective observational study run between September 2019 and August 2020. All patients, during the first visit conducted in an outpatient clinic, were recruited in a specific database. Subsequently, surgery was planned in election on one day surgery, patients were administered a specific questionnaire aiming at the identification of any pain and its exact location. The Inguinal Pain Questionnarie (IPQ) was used. During the surgical procedure the selective neurectomy of the 3 nerves has been documented, the entire population of patients has undergone a standardized surgical treatment. At the end of surgery, a follow-up was carried out administering two questionnaires (IPQ Short Form Modified and the IPQ Short Form Paresthesia Modified) concerning the possible chronic post-operative pain and the eventual paresthesia. The questionnaires were administered at first, third and sixth month from the date of surgery. RESULTS: A total of 266 patients were screened from September 2019 to October 2020. Fiftyseven male patients were included in the study with a confirmed diagnosis of primary inguinal hernia. Clinical data, baseline characteristics and outcomes are described. Preoperatively, at the time of IPQ administration, 1.8% of patients had a pain score of 6, 10% of 5, 21% of 4, 31% of 3, 28% with a score of 2 and 7% of patients with a score of 1. In all cases the ileoinguinals and ileohypogastric nerves found were subjected to neurectomy, in 19% of cases also the genitofemoral nerve was subjected to surgical resection. At the end of the follow-up, the first questionnaire (IPQ Short Form Modified) results did show that, among the total of patients who had an open prosthetic hernioplasty with extensive nerves resection in the inguinal canal, 84% of them indicated a pain score equal to 0 (no pain) after 6 months of treatment and only 1.7% indicated a score equal to 4. Analyzing the second questionnaire on paresthesia (IPQ Short Form Paresthesia Modified), 79% of patients indicated a score equal to 0 by describing no paresthesia and no changes in sensitivity; 15.7% score 1; 3.5% score 2; 1.7% score 3. CONCLUSIONS: Based on our experience and according to the modern literature, we would advise prophylactic total neurectomy of the inguinal canal nerves during prosthetic inguinal hernioplasty. KEY WORDS: Abdominal Surgery, Chronic pain, Inguinal hernioplasty, Neurectomy, Paresthesia.


Subject(s)
Chronic Pain , Hernia, Inguinal , Neuralgia , Chronic Pain/etiology , Chronic Pain/prevention & control , Chronic Pain/surgery , Denervation , Hernia, Inguinal/diagnosis , Herniorrhaphy/adverse effects , Herniorrhaphy/methods , Humans , Male , Neuralgia/etiology , Neuralgia/prevention & control , Pain, Postoperative/etiology , Pain, Postoperative/prevention & control , Surgical Mesh
2.
Ann Ital Chir ; 93: 229-234, 2022.
Article in English | MEDLINE | ID: mdl-35476670

ABSTRACT

INTRODUCTION: Several studies have suggested that intracorporeal anastomosis (IC) has advantages over extracorporeal anastomosis (EC) in laparoscopic right colectomy. Scientific evidence is lacking. The aim is to define the possible benefits of intracorporeal anastomosis compared with extracorporeal anastomosis in elective surgery. METHODS: A single-centre retrospective study was performed. The primary endpoint was duration of hospital stay. Secondary outcomes included operative time, bowel recovery, conversion to open surgery and postoperative complications. RESULTS: In the IC group mean hospital stay was 7,100 days, mean age was 70,5 years, mean operating time was 233 minutes and mean time to restoration of digestive function was 3,950 days. In the EC group mean hospital stay was 9,455 days, mean age was 72,55 years, mean operating time was 183 minutes, mean time to restoration of digestive function was 5,364 days. CONCLUSION: This study shows many clinical outcomes advantages for the intracorporeal anastomosis technique in laparoscopic right colectomy. IA was associated with earlier bowel recovery, decreased hospital stay and fewer complications; operative time was shorter in EA KEY WORDS: Anastomosis, Colon cancer, Laparoscopy, Hemicolectomy, Retrospective.


Subject(s)
Colonic Neoplasms , Laparoscopy , Anastomosis, Surgical/methods , Colectomy/methods , Colonic Neoplasms/surgery , Humans , Laparoscopy/methods , Retrospective Studies
3.
Ann Med Surg (Lond) ; 74: 103260, 2022 Feb.
Article in English | MEDLINE | ID: mdl-35145658

ABSTRACT

INTRODUCTION: Total mesorectal excision (TME) performed for the first time by Held through an open approach, it has become the standard technique for the surgical treatment of rectal cancer. The aim the of this meta-analysis is to compare the outcomes provided by TaTME than LaTME. MATERIAL AND METHODS: In this meta-analysis, we included all comparative studies, prospective and retrospective, which addressed in low and middle rectal cancer, a comparison between TaTME and LaTME. A search was performed through MEDLINE and Cochrane Database. 846 records were identified. RESULTS: Eight relevant studies have been included in this meta-analysis. The studies were from France, Russia, USA, Netherlands, Taiwan, Egypt. The eight studies including 471 patients with middle or low rectal cancer. CONCLUSION: The meta-analysis confirmed safety of TaTME for low and middle rectal cancer. TaTME can lead to a high quality of rectal cancer resection specimen.

5.
Nat Commun ; 12(1): 6457, 2021 11 09.
Article in English | MEDLINE | ID: mdl-34753930

ABSTRACT

The gram-negative bacterium Vibrio cholerae is the causative agent of the diarrhoeal disease cholera and is responsible for seven recorded pandemics. Several factors are postulated to have led to the decline of 6th pandemic classical strains and the rise of El Tor biotype V. cholerae, establishing the current 7th pandemic. We investigated the ability of classical V. cholerae of the 2nd and 6th pandemics to engage their type six secretion system (T6SS) in microbial competition against non-pandemic and 7th pandemic strains. We report that classical V. cholerae underwent sequential mutations in T6SS genetic determinants that initially exposed 2nd pandemic strains to microbial attack by non-pandemic strains and subsequently caused 6th pandemic strains to become vulnerable to El Tor biotype V. cholerae intraspecific competition. The chronology of these T6SS-debilitating mutations agrees with the decline of 6th pandemic classical strains and the emergence of 7th pandemic El Tor V. cholerae.


Subject(s)
Type VI Secretion Systems/physiology , Vibrio cholerae/physiology , Mutation/genetics , Type VI Secretion Systems/genetics , Vibrio cholerae/genetics
6.
Microbiol Resour Announc ; 10(22): e0030821, 2021 Jun 03.
Article in English | MEDLINE | ID: mdl-34080905

ABSTRACT

Vibrio cholerae is the etiologic agent of cholera, an acute and often fatal diarrheal disease that affects millions globally. We report the draft genome sequences of 13 non-O1/O139 V. cholerae strains isolated from the Rio Grande Delta in Texas. These genomes will aid future analyses of environmental serovars.

7.
Ann Ital Chir ; 92: 1-5, 2021.
Article in English | MEDLINE | ID: mdl-33746124

ABSTRACT

INTRODUCTION: Laparoscopy appendectomy (LA) is the most widely used method for the treatment of acute appendicitis (AA). The interest has shifted towards the mini-incision open method (MOA). MATERIALS AND METHODS: A retrospective study was conducted considering all patients who underwent surgery due to suspected appendicitis from December 2014 to January 2019. The final analysis included 234 patients. The following data were collected: patient age, sex, surgery duration, hospitalization time, wound infections, and mortality. RESULTS: The average time of surgery was 69.89 minutes in the LA group and 62.17 minutes in the MOA group, while the average time of postoperative hospitalization was respectively 5.579 days and 5.143 days. Wound infections occurred in 2 patients in the LA group and in 3 patients in the MOA group. CONCLUSION: Laparoscopic appendectomy has a similar operating time, hospitalization time and wound infections as Mini-incision open appendectomy. Therefore,both techniques are to be considered valid. KEY WORDS: Appendicitis, Laparoscopic appendectomy, Appendectomy, Instrumentation, Open approach.


Subject(s)
Appendicitis , Laparoscopy , Appendectomy , Appendicitis/surgery , Humans , Length of Stay , Postoperative Complications/epidemiology , Postoperative Complications/etiology , Retrospective Studies , Treatment Outcome
8.
Updates Surg ; 69(2): 211-215, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28646422

ABSTRACT

Complications of thyroidectomy are hypoparathyroidism, recurrent laryngeal nerve palsy, and hemorrhage. These complications have a low incidence. Hypoparathyroidism is the most frequent complication of total thyroidectomy. Its incidence varies between 0.5 and 65%. This complication is also visible after reoperation for recurrent disease and in patients previously treated with radioiodine. Damage to the recurrent laryngeal nerve can be temporary or permanent, unilateral or bilateral. The bilateral lesion, associated with severe episodes of breathlessness, is a rare complication (0.4%). Intraoperative control of nerves is crucial to prevent damage. The hematoma creates an obstacle to venous and lymphatic flow and consequently breathing difficulties. The preventive hemostasis during surgery is important. Therapeutic treatment is described.


Subject(s)
Postoperative Complications/prevention & control , Thyroidectomy , Hemorrhage/prevention & control , Hemostasis, Surgical/methods , Humans , Hypoparathyroidism/prevention & control , Vocal Cord Paralysis/prevention & control
9.
Toxicon ; 135: 84-92, 2017 Sep 01.
Article in English | MEDLINE | ID: mdl-28633930

ABSTRACT

Two phospholipase A2s (PLA2s), Asp49 (D49) and Lys49 (K49), were purified by one-step reverse-phase high performance liquid chromatography (RP-HPLC) from the venom of each of the three subspecies of cottonmouth snake, Western cottonmouth (Agkistrodon piscivorus leucostoma; Apl), Eastern cottonmouth (Agkistrodon piscivorus piscivorus; App) and Florida cottonmouth (Agkistrodon piscivorus conanti; Apc). Venom protein profiles and PLA2s elution pattern of the three cottonmouth snakes were remarkably similar displaying four similar sharp and two wide peaks; in all cases K49 PLA2 eluted first followed by D49 PLA2. The yields of K49 and D49 PLA2s were, respectively, 13.2 and 17.5 mg/g venom from the Western cottonmouth, 16.8 and 19.2 mg/g from the Eastern cottonmouth, and 17.3 and 22.7 mg/g from the Florida cottonmouth. Biochemical and enzymatic techniques were used to characterize the purified PLA2. The amino acid sequences of all three K49PLA2s were identical; App-D49 and Apc-D49 were also identical but displayed a single amino acid difference with Apl-D49. To our knowledge, this is the first report on the amino acid sequence and molecular mass of Apc-D49 and Apc-K49 PLA2s from Florida cottonmouth venom. As expected, PLA2 enzymatic analysis revealed that D49 PLA2s from all three venoms hydrolyze phospholipids to a similar extent, whereas no phospholipid hydrolysis was detectable by any of the K49 PLA2s purified. Cottonmouth snake venoms contain abundant PLA2 isoforms, thus the identification of PLA2s in these venoms is of interest to facilitate the purification of specific PLA2 from rich sources of subspecies venom for future biological and biomedical research. Results of this study also contribute towards the understanding of venom protein profiles, variation, and evolution in subspecies of venomous snakes.


Subject(s)
Agkistrodon , Crotalid Venoms/enzymology , Phospholipases A2/chemistry , Phospholipases A2/isolation & purification , Amino Acid Sequence , Animals , Protein Isoforms
10.
Sci Rep ; 7: 45133, 2017 03 22.
Article in English | MEDLINE | ID: mdl-28327641

ABSTRACT

Type VI secretion systems (T6SS) enable bacteria to engage neighboring cells in contact-dependent competition. In Vibrio cholerae, three chromosomal clusters each encode a pair of effector and immunity genes downstream of those encoding the T6SS structural machinery for effector delivery. Different combinations of effector-immunity proteins lead to competition between strains of V. cholerae, which are thought to be protected only from the toxicity of their own effectors. Screening of all publically available V. cholerae genomes showed that numerous strains possess long arrays of orphan immunity genes encoded in the 3' region of their T6SS clusters. Phylogenetic analysis reveals that these genes are highly similar to those found in the effector-immunity pairs of other strains, indicating acquisition by horizontal gene transfer. Extensive genomic comparisons also suggest that successive addition of effector-immunity gene pairs replaces ancestral effectors, yet retains the cognate immunity genes. The retention of old immunity genes perhaps provides protection against nearby kin bacteria in which the old effector was not replaced. This mechanism, combined with frequent homologous recombination, is likely responsible for the high diversity of T6SS effector-immunity gene profiles observed for V. cholerae and closely related species.


Subject(s)
Immunity/genetics , Type VI Secretion Systems/genetics , Type VI Secretion Systems/immunology , Vibrio cholerae/genetics , Vibrio cholerae/immunology , Computational Biology/methods , Gene Transfer, Horizontal , Genome, Bacterial , Genomics/methods , Molecular Sequence Annotation , Phylogeny , Recombination, Genetic , Vibrio cholerae/classification
11.
Int Microbiol ; 20(3): 130-137, 2017 Sep.
Article in English | MEDLINE | ID: mdl-29446804

ABSTRACT

Vibrio cholerae is a diverse species that inhabits a wide range of environments from copepods in brackish water to the intestines of humans. In order to remain competitive, V. cholerae uses the versatile type-VI secretion system (T6SS) to secrete anti-prokaryotic and anti-eukaryotic effectors. In addition to competing with other bacterial species, V. cholerae strains also compete with one another. Some strains are able to coexist, and are referred to as belonging to the same compatibility group. Challenged by diverse competitors in various environments, different V. choleare strains secrete different combination of effectors - presumably to best suit their niche. Interestingly, all pandemic V. cholerae strains encode the same three effectors. In addition to the diversity displayed in the encoded effectors, the regulation of V. cholerae also differs between strains. Two main layers of regulation appear to exist. One strategy connects T6SS activity with behavior that is suited to fighting eukaryotic cells, while the other is linked with natural competence - the ability of the bacterium to acquire and incorporate extracellular DNA. This relationship between bacterial killing and natural competence is potentially a source of diversification for V. cholerae as it has been shown to incorporate the DNA of cells recently killed through T6SS activity. It is through this process that we hypothesize the transfer of virulence factors, including T6SS effector modules, to happen. Switching of T6SS effectors has the potential to change the range of competitors V. cholerae can kill and to newly define which strains V. cholerae can co-exist with, two important parameters for survival in diverse environments.


Subject(s)
Bacterial Proteins , Type VI Secretion Systems , Vibrio cholerae/genetics , Virulence Factors , DNA, Bacterial , Genotype
12.
Nat Commun ; 5: 3549, 2014 Apr 01.
Article in English | MEDLINE | ID: mdl-24686479

ABSTRACT

Vibrio cholerae is a Gram-negative bacterial pathogen that consists of over 200 serogroups with differing pathogenic potential. Only strains that express the virulence factors cholera toxin (CT) and toxin-coregulated pilus (TCP) are capable of pandemic spread of cholera diarrhoea. Regardless, all V. cholerae strains sequenced to date harbour genes for the type VI secretion system (T6SS) that translocates effectors into neighbouring eukaryotic and prokaryotic cells. Here we report that the effectors encoded within these conserved gene clusters differ widely among V. cholerae strains, and that immunity proteins encoded immediately downstream from the effector genes protect their host from neighbouring bacteria producing corresponding effectors. As a consequence, strains with matching effector-immunity gene sets can coexist, while strains with different sets compete against each other. Thus, the V. cholerae T6SS contributes to the competitive behaviour of this species.


Subject(s)
Bacterial Proteins/metabolism , Bacterial Secretion Systems , Cholera/microbiology , Vibrio cholerae/metabolism , Bacterial Proteins/genetics , Gene Expression Regulation, Bacterial , Humans , Molecular Sequence Data , Phylogeny , Vibrio cholerae/classification , Vibrio cholerae/genetics , Vibrio cholerae/isolation & purification , Virulence Factors/genetics , Virulence Factors/metabolism
13.
Front Microbiol ; 4: 384, 2013.
Article in English | MEDLINE | ID: mdl-24368907

ABSTRACT

Diarrheal diseases are the second-most common cause of death among children under the age of five worldwide. Cholera alone, caused by the marine bacterium Vibrio cholerae, is responsible for several million cases and over 120,000 deaths annually. When contaminated water is ingested, V. cholerae passes through the gastric acid barrier, penetrates the mucin layer of the small intestine, and adheres to the underlying epithelial lining. V. cholerae multiplies rapidly, secretes cholera toxin, and exits the human host in vast numbers during diarrheal purges. How V. cholerae rapidly reaches such high numbers during each purge is not clearly understood. We propose that V. cholerae employs its bactericidal type VI secretion system to engage in intraspecies and intraguild predation for nutrient acquisition to support rapid growth and multiplication.

14.
J Vis Exp ; (80)2013 Oct 08.
Article in English | MEDLINE | ID: mdl-24146001

ABSTRACT

Electroporation has become a widely used method for rapidly and efficiently introducing foreign DNA into a wide range of cells. Electrotransformation has become the method of choice for introducing DNA into prokaryotes that are not naturally competent. Electroporation is a rapid, efficient, and streamlined transformation method that, in addition to purified DNA and competent bacteria, requires commercially available gene pulse controller and cuvettes. In contrast to the pulsing step, preparation of electrocompetent cells is time consuming and labor intensive involving repeated rounds of centrifugation and washes in decreasing volumes of sterile, cold water, or non-ionic buffers of large volumes of cultures grown to mid-logarithmic phase of growth. Time and effort can be saved by purchasing electrocompetent cells from commercial sources, but the selection is limited to commonly employed E. coli laboratory strains. We are hereby disseminating a rapid and efficient method for preparing electrocompetent E. coli, which has been in use by bacteriology laboratories for some time, can be adapted to V. cholerae and other prokaryotes. While we cannot ascertain whom to credit for developing the original technique, we are hereby making it available to the scientific community.


Subject(s)
Bacteriological Techniques/methods , Electroporation/methods , Escherichia coli/physiology , Vibrio cholerae/physiology , Escherichia coli/cytology , Escherichia coli/genetics , Escherichia coli/growth & development , Transformation, Bacterial , Vibrio cholerae/cytology , Vibrio cholerae/genetics , Vibrio cholerae/growth & development
15.
Soft Matter ; 9(14): 3871-3876, 2013 Apr 14.
Article in English | MEDLINE | ID: mdl-23894249

ABSTRACT

Biofilms are surface-mounted, multicellular communities of microbes. Biofilms are often associated with chronic infections that resist treatment, evade the immune system, and damage host tissue. An essential characteristic of the biofilm state is that constituent organisms are bound in a polymeric matrix. This matrix gives the system spatial structure and clusters bacteria near each other, facilitating intercellular interactions. The Pseudomonas aeruginosa strain PAO1 is widely studied as a model biofilm-forming organism. The polymeric matrix of PAO1 biofilms is dominated by two bacteria-produced extracellular polymers, Pel and Psl. We use a combination of optical and atomic force microscopy to examine the roles of these polymers in very early biofilm development. In agreement with other researchers, we find that Psl mediates strong attachment to a glass surface. We find that Pel alone can mediate some attachment, but not as permanent as that mediated by Psl. Unexpectedly, we find that Pel promotes symmetric attachment, in the form of rod-shaped bacteria lying down flat on the surface, and that the presence of Pel makes attachment forces more short-ranged than they are with Psl alone. We suggest that these effects may result from synergistic interactions of Pel with the Psl polymeric matrix.

16.
J Med Microbiol ; 62(Pt 7): 1011-1014, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23538564

ABSTRACT

Cholera toxin (CT), the principal virulence factor secreted by Vibrio cholerae, is an A-B5 type exotoxin that binds to host cell GM1-gangliosides and is responsible for cholera diarrhoea. We tested the hypothesis that the cyclic hexasaccharide α-cyclodextrin (α-CD), but not the cyclic heptasaccharides methyl-ß-cyclodextrin (MD-ß-CD) and hydroxypropyl-ß-cyclodextrin (HP-ß-CD) inhibit binding of CT to GM1-gangliosides. We report that α-CD decreases CT binding to GM1-ganglioside-coated microtitre plate wells and on the surface of fixed HeLa cells in a concentration-dependent manner, suggesting that this may be a promising lead for the development of compounds with therapeutic properties.


Subject(s)
Cholera Toxin/chemistry , Gangliosides/chemistry , alpha-Cyclodextrins/pharmacology , 2-Hydroxypropyl-beta-cyclodextrin , Enzyme-Linked Immunosorbent Assay , HeLa Cells , Humans , alpha-Cyclodextrins/chemistry , beta-Cyclodextrins/chemistry
17.
PLoS One ; 7(10): e48320, 2012.
Article in English | MEDLINE | ID: mdl-23110230

ABSTRACT

The type VI secretion system (T6SS) mediates protein translocation across the cell membrane of Gram-negative bacteria, including Vibrio cholerae - the causative agent of cholera. All V. cholerae strains examined to date harbor gene clusters encoding a T6SS. Structural similarity and sequence homology between components of the T6SS and the T4 bacteriophage cell-puncturing device suggest that the T6SS functions as a contractile molecular syringe to inject effector molecules into prokaryotic and eukaryotic target cells. Regulation of the T6SS is critical. A subset of V. cholerae strains, including the clinical O37 serogroup strain V52, express T6SS constitutively. In contrast, pandemic strains impose tight control that can be genetically disrupted: mutations in the quorum sensing gene luxO and the newly described regulator gene tsrA lead to constitutive T6SS expression in the El Tor strain C6706. In this report, we examined environmental V. cholerae isolates from the Rio Grande with regard to T6SS regulation. Rough V. cholerae lacking O-antigen carried a nonsense mutation in the gene encoding the global T6SS regulator VasH and did not display virulent behavior towards Escherichia coli and other environmental bacteria. In contrast, smooth V. cholerae strains engaged constitutively in type VI-mediated secretion and displayed virulence towards prokaryotes (E. coli and other environmental bacteria) and a eukaryote (the social amoeba Dictyostelium discoideum). Furthermore, smooth V. cholerae strains were able to outcompete each other in a T6SS-dependent manner. The work presented here suggests that constitutive T6SS expression provides V. cholerae with an advantage in intraspecific and interspecific competition.


Subject(s)
Bacterial Secretion Systems/physiology , Vibrio cholerae/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Bacterial Secretion Systems/genetics , Gene Expression Regulation, Bacterial/genetics , Gene Expression Regulation, Bacterial/physiology , Vibrio cholerae/genetics , Vibrio cholerae/physiology
18.
J Med Chem ; 55(18): 7998-8006, 2012 Sep 27.
Article in English | MEDLINE | ID: mdl-22954387

ABSTRACT

Protective antigen (PA), lethal factor, and edema factor, the protein toxins of Bacillus anthracis , are among its most important virulence factors and play a key role in infection. We performed a virtual ligand screen of a library of 10000 members to identify compounds predicted to bind to PA and prevent its oligomerization. Four of these compounds slowed PA association in a FRET-based oligomerization assay, and two of those protected cells from intoxication at concentrations of 1-10 µM. Exploration of the protective mechanism by Western blot showed decreased SDS-resistant PA oligomer on cells and, surprisingly, decreased amounts of activated PA. In vitro assays showed that one of the inhibitors blocked furin-mediated cleavage of PA, apparently through its binding to the PA substrate. Thus, we have identified inhibitors that can independently block both PA's cleavage by furin and its subsequent oligomerization. Lead optimization on these two backbones may yield compounds with high activity and specificity for the anthrax toxins.


Subject(s)
Antigens, Bacterial/chemistry , Antigens, Bacterial/metabolism , Bacterial Toxins/chemistry , Bacterial Toxins/metabolism , Protein Multimerization/drug effects , Proteolysis/drug effects , Small Molecule Libraries/pharmacology , Animals , Antigens, Bacterial/toxicity , Bacterial Toxins/antagonists & inhibitors , Bacterial Toxins/toxicity , Cell Line , Computational Biology , Drug Evaluation, Preclinical , Humans , Mice , Molecular Docking Simulation , Porosity , Protein Structure, Quaternary , Small Molecule Libraries/metabolism
19.
Infect Immun ; 76(8): 3595-605, 2008 Aug.
Article in English | MEDLINE | ID: mdl-18490456

ABSTRACT

Vibrio cholerae is a gram-negative human intestinal pathogen that causes the diarrheal disease cholera. Humans acquire cholera by ingesting V. cholerae-contaminated food or water. Upon ingestion, V. cholerae encounters several barriers to colonization, including bile acid toxicity and antimicrobial products of the innate immune system. In many gram-negative bacteria, resistance to the antimicrobial effects of these products is mediated by RND (resistance-nodulation-division) family efflux systems. In this study we tested the hypothesis that the V. cholerae RND efflux systems are required for antimicrobial resistance and virulence. The six V. cholerae genes encoding RND efflux pumps were deleted from the genome of the O1 El Tor strain N16961, resulting in the generation of 14 independent RND deletion mutants, including one RND-null strain. Determination of the antimicrobial susceptibilities of the mutants revealed that the RND efflux systems were responsible for resistance to multiple antimicrobial compounds, including bile acids, antimicrobial peptides, and antibiotics. VexB (VC0164) was found to be the RND efflux pump primarily responsible for the resistance of V. cholerae to multiple antimicrobial compounds in vitro. In contrast, VexD (VC1757) and VexK (VC1673) encoded efflux pumps with detergent-specific substrate specificities that were redundant with VexB. A strain lacking VexB, VexD, and VexK was attenuated in the infant mouse model, and its virulence factor production was unaffected. In contrast, a V. cholerae RND-null strain produced significantly less cholera toxin and fewer toxin-coregulated pili than the wild type and was unable to colonize the infant mouse. The decreased virulence factor production in the RND-null strain was linked to reduced transcription of tcpP and toxT. Our findings show that the V. cholerae RND efflux systems are required for antimicrobial resistance, optimal virulence factor production, and colonization of the infant mouse.


Subject(s)
Drug Resistance, Multiple, Bacterial , Intestine, Small/microbiology , Membrane Transport Proteins/physiology , Vibrio cholerae O1/physiology , Virulence Factors/metabolism , Animals , Animals, Newborn , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/biosynthesis , Cholera/microbiology , Cholera Toxin/metabolism , Fimbriae, Bacterial/metabolism , Gene Deletion , Gene Expression Profiling , Gene Order , Genetic Complementation Test , Membrane Transport Proteins/genetics , Mice , Sequence Homology, Amino Acid , Transcription Factors/biosynthesis , Vibrio cholerae O1/drug effects , Vibrio cholerae O1/metabolism , Vibrio cholerae O1/pathogenicity
20.
Microbiol Immunol ; 50(12): 899-927, 2006.
Article in English | MEDLINE | ID: mdl-17179659

ABSTRACT

Cholera, a diarrheal disease, is known for explosive epidemics that can quickly kill thousands. Endemic cholera is a seasonal torment that also has a significant mortality. Not all nations with extensive rural communities can achieve the required infrastructure or behavioral changes to prevent epidemic or endemic cholera. For some communities, a single-dose cholera vaccine that protects those at risk is the most efficacious means to reduce morbidity and mortality. It is clear that our understanding of what a protective cholera immune response is has not progressed at the rate our understanding of the pathogenesis and molecular biology of cholera infection has. This review addresses V. cholerae lipopolysaccharide (LPS)-based immunogens because LPS is the only immunogen proven to induce protective antibody in humans. We discuss the role of anti-LPS antibodies in protection from cholera, the importance and the potential role of B cell subsets in protection that is based on their anatomical location and the intrinsic antigen-receptor specificity of various subsets is introduced.


Subject(s)
B-Lymphocytes/immunology , Cholera Vaccines/immunology , Cholera/immunology , Lipopolysaccharides/immunology , Vibrio cholerae/immunology , Antibodies, Bacterial/biosynthesis , B-Lymphocytes/drug effects , Cholera Vaccines/administration & dosage , Humans
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