Richard P. Wenzel

Bio: Richard P. Wenzel is an academic researcher from University of Maryland, Baltimore. The author has contributed to research in topics: Vibrio cholerae & Diarrhea. The author has an hindex of 1, co-authored 1 publications receiving 305 citations.

Response of man to infection with Vibrio cholerae. I. Clinical, serologic, and bacteriologic responses to a known inoculum.

Abstract: The spectrum of illness and the immunologic response produced by cholera in volunteers were studied. The strains of Vibrio cholerae used were classical Inaba 569B and classical Ogawa 395. An oral dose of 108 organisms in buffered saline was required to induce the diarrhea of cholera. When given with live organisms, NaHCO3 lowered the infecting dose from 108 to 104 organisms. Clinical manifestations of infection varied from culturally positive formed stools to "rice water" diarrhea. Severe diarrhea did not have an explosive onset but rather progressively increased in volume during a 24-hr period. In 45% of cases the stool was positive for V. cholerae before the onset of diarrhea. Titers of vibriocidal antibody rose after diarrhea, peaked the second week after challenge, and rapidly fell during the next four weeks.

Plasmid-controlled colonization factor associated with virulence in Esherichia coli enterotoxigenic for humans.

Abstract: An enterotoxin-producing strain of Escherichia coli isolated from a case of cholera-like diarrhea (E. coli strain H-10407) was found to possess a surface-associated colonization factor. Colonization was manifested as the ability of small inocula (10(5) bacteria) to attain large (10(9)) populations in the infant rabbit intestine with a concomitant diarrheal response. A laboratory-passed derivative of E. coli H-10407, designated H-10407-P, failed to exhibit an increase in population in the infant rabbit and also failed to induce diarrhea. Cell-free culture supernatant fluids of E. coli H-10407 and H-10407-P produced equivalent enterotoxic responses in infant and in adult rabbits. Specific anti-colonization factor antiserum was produced by adsorbing hyperimmune anti-H-10407 serum with both heat-killed and living cells E. coli H-10407-P. This specific adsorbed serum protected infant rabbits from challenge with living E. coli H-10407 although the serum did not possess bactericidal activity. The anti-colonization factor serum did not agglutinate a strain of E. coli K-12 possessing the K88 colonization factor peculiar to E. coli enterotoxigenic for swine. By electron microscopy it was demonstrated that E. coli H-10407, but not H10407-, possessed pilus-like surface structures which agglutinated with the specific adsorbed (anti-colonization factor) antiserum. E. coli H-10407 possessed three species of plasmid deoxyribonucleic acid, measuring 60 X 10(6), 42 X 10(6), and 3.7 X 10(6) daltons, respectively. E. coli H-10407-P possessed only the 42 X 10(6)- and the 3.7 X 10(6)-dalton plasmid species. Spontaneous loss of the specific H-10407 surface-associated antigen was accompanied by loss of the 60 X 10(6)-dalton species of plasmid deoxyribonucleic acid and loss of colonizing ability. Thus, it is concluded that the E. coli colonization factor described here is a virulence factor which may play an important and possibly essential role in naturally occurring E. coli enterotoxic diarrhea in man.

Infections of the Gastrointestinal Tract

Abstract: laboratory diagnosis of gastrointestinal infections escherichia coli contacting microvilli on the surface of chapter 11 gastrointestinal tract infections wiley: home simultaneous gastrointestinal infections in children and gastrointestinal tract infections gastro-intestinal tract parasitic infections of gastrointestinal tract infections of the gastrointestinal tract microbiology infections of the gastrointestinal tract infections of the gastrointestinal tract blwood viral infections of the gastrointestinal tract springer acute and chronic infections of the gastrointestinal tract gastrointestinal tract infections link.springer protozoan infections of the gastrointestinal tract saludesa infections of the gastro-intestinal tract afrivip book reviews practical gastroenterology gastrointestinal tract infections acute diarrhea and article nosocomial infections in the neonatal intensive shortand long-term effects of bacterial gastrointestinal infections of the gastrointestinal tract springer abdominal infections university of california, los angeles infections of the gastrointestinal tract konsool gastrointestinal tract infections pharmadivh infections of the gastrointestinal tract microbiology acute and chronic infections of the gastrointestinal tract infections of the gastrointestinal tract microbiology the infections of the gastrointestinal tract aoke a guide to utilization of the microbiology laboratory for pathophysiology of gastrointestinal nematode infections in infections of the gastrointestinal tract in the infections of the gastrointestinal tract campen ltc gastrointestinal (gi) tract & norovirus infection guidelines for prevention of nosocomial pneumonia infections of the gastro-intestinal tract afrivip infectious diseases: digestive system pediatric urinary tract infections stanford medicine virus infections of the gastrointestinal tract of poultry therapeutics of pediatric urinary tract infections preventing infections in non-hospital settings: long-term care prolonged and exclusive breastfeeding reduces the risk of ltc gastrointestinal (gi) tract infection worksheet basidiobolomycosis: an emerging fungal infection of the urinary tract infection michigan medicine gastrointestinal tract: bacterial infections bacterial infections of the digestive tract

Ecological relationships between Vibrio cholerae and planktonic crustacean copepods.

Abstract: Strains of Vibrio cholerae, both O1 and non-O1 serovars, were found to attach to the surfaces of live copepods maintained in natural water samples collected from the Chesapeake Bay and Bangladesh environs. The specificity of attachment of V. cholerae to live copepods was confirmed by scanning electron microscopy, which revealed that the oral region and egg sac were the most heavily colonized areas of the copepods. In addition, survival of V. cholerae in water was extended in the presence of live copepods. Attachment of viable V. cholerae cells to copepods killed by exposure to -60 degrees C was not observed. Furthermore, survival of V. cholerae was not as long in the presence of dead copepods as in the live copepod system. A strain of Vibrio parahaemolyticus was also seen to attach to copepod surfaces without effect on survival of the organism in water. The attachment of vibrios to copepods was concluded to be significant since strains of other bacteria, including Pseudomonas sp. and Escherichia coli, did not adhere to live or dead copepods. Attachment of V. cholerae to live copepods is suggested to be an important factor of the ecology of this species in the aquatic environment, as well as in the epidemiology of cholera, for which V. cholerae serovar O1 is the causative agent.

Cholera transmission: the host, pathogen and bacteriophage dynamic

Abstract: Zimbabwe offers the most recent example of the tragedy that befalls a country and its people when cholera strikes The 2008–2009 outbreak rapidly spread across every province and brought rates of mortality similar to those witnessed as a consequence of cholera infections a hundred years ago In this Review we highlight the advances that will help to unravel how interactions between the host, the bacterial pathogen and the lytic bacteriophage might propel and quench cholera outbreaks in endemic settings and in emergent epidemic regions such as Zimbabwe