ABSTRACT A multistate outbreak of listeriosis occurred in the United States in 1998 with illness onset dates between August and December. The outbreak caused illness in 108 persons residing in 24 states and caused 14 deaths and four miscarriages or stillbirths. This outbreak was detected by public health officials in Tennessee and New York who observed significant increases over expected listeriosis cases in their states. Subsequently, the Centers for Disease Control and Prevention (CDC) began laboratory characterization of clinical isolates of Listeria monocytogenes by serotyping and restriction fragment length polymorphism analysis using pulsed-field gel electrophoresis (PFGE). For the purpose of this investigation, outbreak-related isolates were defined as those that had a specific AscI-PFGE pattern and indistinguishable or highly similar (no more than 2 band difference in 26 bands) ApaI-PFGE patterns when their DNA was restricted by AscI and ApaI restriction enzymes. Timely availability of molecular subtyping results enabled epidemiologists to separate outbreak cases from temporally associated sporadic cases in the same geographic areas and facilitated the identification of contaminated hot dogs manufactured at a single commercial facility as the source of the outbreak. During the investigation of this outbreak, a standardized protocol for subtyping L. monocytogenes by PFGE was developed and disseminated to public health laboratories participating with CDC's PulseNet network; these laboratories were requested to begin routine PFGE subtyping of L. monocytogenes.

There is no standard immunoassay for evaluating immune responses to meningococcal vaccines. We developed an enzyme-linked immunosorbent assay to measure total levels of antibody to Neisseria meningitidis group A capsular polysaccharide. Five laboratories measured the antibody levels in six paired pre- and postvaccination serum samples by using the enzyme-linked immunosorbent assay. Methylated human serum albumin was used to bind native group A polysaccharide to microtiter plate surfaces. The between-laboratory coefficients of variation for pre- and postvaccination sera had ranges of 31 to 91 and 17 to 31, respectively. The mean laboratory coefficients of variation for pre- and postvaccination sera, respectively, were 17 and 11 (Molecular Biology Laboratory, Centers for Disease Control), 12 and 15 (Immunodiagnostic Methods Laboratory, Centers for Disease Control), 22 and 19 (Dana-Farber Cancer Institute), 38 and 38 (Bacterial Polysaccharide Laboratory, U.S. Food and Drug Administration), and 11 and 10 (Praxis Biologics, Inc.). Standardization of this enzyme-linked immunosorbent assay should allow interlaboratory comparison of meningococcal vaccine immunogenicity, thus providing a laboratory-based assessment tool for evaluating meningococcal vaccines.

A panel of strains for evaluating Neisseria gonorrhoeae serologic reagents was developed. The strains selected for the panel were antigenically diverse and representative of strains isolated worldwide and had been isolated from a variety of anatomic sites. A few strains with characteristics that can cause problems in serologic tests were included. The panel of 52 gonococcal and 20 nongonococcal strains was used to evaluate two commercially produced kits with monoclonal antibody reagents, GonoGen and Phadebact, and one Phadebact kit with absorbed rabbit antiserum. The GonoGen reagent correctly identified all gonococcal strains and did not react with any of the nongonococcal strains. The Phadebact absorbed antiserum reagent correctly identified 47 of 48 gonococcal strains but reacted with 2 of the 20 nongonococcal strains. The Phadebact monoclonal antibody reagent correctly identified all the gonococcal strains; however, it gave positive reactions with 8 and trace reactions with 4 of the 20 nongonococcal strains.

Journal Article Frequency and Distribution in the United States of Strains of Neisseria gonorrhoeae with Plasmid-Mediated, High-Level Resistance to Tetracycline Get access Joan S. Knapp, Joan S. Knapp Sexually Transmitted Diseases Laboratory Program, Center for Infectious Diseases, and the Epidemiology Research Branch, Center for Prevention Services, Centers for Disease Control, Atlanta, Georgia Please address requests for reprints to Dr. Joan S. Knapp, Center for Infectious Diseases, Neisseria Research Laboratory, Sexually Transmitted Diseases Laboratory Program, Building 1, Room 3254, Centers for Disease Control, Atlanta, Georgia 30333. Search for other works by this author on: Oxford Academic PubMed Google Scholar Jonathan M. Zenilman, Jonathan M. Zenilman Sexually Transmitted Diseases Laboratory Program, Center for Infectious Diseases, and the Epidemiology Research Branch, Center for Prevention Services, Centers for Disease Control, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar James W. Biddle, James W. Biddle Sexually Transmitted Diseases Laboratory Program, Center for Infectious Diseases, and the Epidemiology Research Branch, Center for Prevention Services, Centers for Disease Control, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar Goldie H. Perkins, Goldie H. Perkins Sexually Transmitted Diseases Laboratory Program, Center for Infectious Diseases, and the Epidemiology Research Branch, Center for Prevention Services, Centers for Disease Control, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar Wallis E. DeWitt, Wallis E. DeWitt Sexually Transmitted Diseases Laboratory Program, Center for Infectious Diseases, and the Epidemiology Research Branch, Center for Prevention Services, Centers for Disease Control, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar Myrtle L. Thomas, Myrtle L. Thomas Sexually Transmitted Diseases Laboratory Program, Center for Infectious Diseases, and the Epidemiology Research Branch, Center for Prevention Services, Centers for Disease Control, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar Steve R. Johnson, Steve R. Johnson Sexually Transmitted Diseases Laboratory Program, Center for Infectious Diseases, and the Epidemiology Research Branch, Center for Prevention Services, Centers for Disease Control, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar Stephen A. Morse Stephen A. Morse Sexually Transmitted Diseases Laboratory Program, Center for Infectious Diseases, and the Epidemiology Research Branch, Center for Prevention Services, Centers for Disease Control, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Infectious Diseases, Volume 155, Issue 4, April 1987, Pages 819–822, https://doi.org/10.1093/infdis/155.4.819 Published: 01 April 1987 Article history Received: 09 June 1986 Revision received: 05 September 1986 Published: 01 April 1987

Between January 1983 and October 1984, 446 cases of infection due to chromosomally mediated resistance in Neisseria gonorrhoeae (CMRNG) were reported in 23 states. Eighty percent were detected as primary penicillin or ampicillin treatment failures. Gonococcal isolates were submitted from 175 (40%) for confirmation of resistance, susceptibility testing, gonococcal strain typing using monoclonal antibodies specific for outer membrane Protein I, and auxotyping. All were typed as Protein I serogroup IB (WII/WIII), and the majority were proline or prototrophic auxotypes. All were resistant in vitro to less than 1 microgram/ml of either penicillin or tetracycline. Comparing CMRNG with penicillinase-producing Neisseria gonorrhoeae (PPNG), we found that CMRNG were significantly more resistant to tetracycline and erythromycin, but PPNG were more resistant to penicillin (P less than .01). Because of increasing reports of gonococcal resistance in the United States, improved surveillance of clinical and laboratory resistance is needed in support of control and treatment recommendations for gonorrhea.

Three strains of Neisseria gonorrhoeae carried novel plasmids of 7.8 megadaltons (mdal) molecular mass in addition to plasmids previously observed in this organism. The presence of the 7.8-mdal plasmids was not accompanied by any distinguishable phenotype in the strain possessing them. Analysis of plasmid DNA with restriction endonucleases showed that these plasmids were composed of three directly repeated copies of a 2.6-mdal cryptic plasmid frequently found in N. gonorrhoeae. In addition, the 7.8-mdal plasmids exhibited characteristics common to the 2.6-mdal plasmid, structural lability and sites resistant to cleavage with HpaII. The concatemeric forms of the cryptic plasmid appear to be stable in these strains and do not undergo internal recombination to produce the 2.6-mdal monomer, nor were higher concatemers detected.

The discovery of 11 persons infected with Vibrio cholerae serogroup O1 (biotype El Tor, serotype Inaba) in southwestern Louisiana in 1978 provided an opportunity to evaluate the serologic response to this agent in North Americans with naturally acquired infection. One antibacterial assay (vibriocidal assay) and two antitoxin assays (enzyme linked immunosorbent assays [ELISA] and rabbit skin permeability factor assay) were used. Antitoxin levels were elevated longer than vibriocidal antibody levels, and asymptomatic infected persons had levels of antitoxin and vibriocidal antibody levels, and asymptomatic infected persons had levels of antitoxin and vibriocidal antibody as high as those of persons with clinical cholera. With use of serologic criteria derived from these studies, one additional person infected with V. cholerae O1 was discovered, and a relatively low (4%-7%) prevalence rate of elevated levels of vibriocidal antibody and antitoxin was found in a serum survey of a community with several known cases. Comparison of the results from the ELISA and the rabbit skin permeability factor assay demonstrated similar rates of elevated levels of antitoxin, but the ELISA required less time and less serum per sample analyzed.

A laboratory investigation was conducted on cultures collected from travelers before, during, and after a trip to Mexico to characterize the etiology of traveler's diarrhea. Four laboratory methods for detecting enterotoxigenicity of Escherichia coli were evaluated: the infant mouse assay, the Chinese hamster ovary (CHO) cell assay, the Y1 adrenal cell assay, and the rabbit ileal loop. Although a number of common enteric pathogens were identified as a cause of traveler's diarrhea, including six serotypes of Salmonella, two serotypes of Shigella, Vibrio parahaemolyticus, Giardia lamblia, and Entamoeba histolytica, enterotoxigenic Escherichia coli was most commonly isolated. Strains were identified that produced only heat-labile enterotoxin (LT), only heat-stable enterotoxin (ST), or both LT and ST. The infant mouse assay yielded results falling into two distinct groups, providing a clear separation of positive and negative cultures. The CHO assay also formed two groups, with positive cultures producing 11% or more of the elongated cells. There was good agreement between the CHO and the Y1 adrenal cell assays for detection of LT. The adrenal cell system for detection of LT was more suitable than the CHO assay for processing large numbers of specimens because of the miniculture modification of this method utilized in this study. The infant mouse method was a simple and reliable method for detecting ST.

In this study we utilized the salt-tolerant characteristics of vibrios to develop a more selective medium by addition of NaCl to thiosulfate citrate bile salts sucrose (TCBS) agar. The effect of adding salt to TCBS agar varied greatly among brands of TCBS agar and between lots of the same brand. The addition of salt at concentrations as high as 1.5% (2.5% total NaCl) caused the inhibition of growth of three species of commonly encountered normal bowel flora and one strain of classical Vibrio cholerae but did not compromise the use of TCBS agar for isolation of V. cholerae biotype El Tor.

Between June 23 and June 30, 1973, 90% of 650 passengers and at least 35% of 299 crew members experienced a diarrheal illness during a 7-day Caribbean cruise aboard a passenger cruise liner. Symptoms were consistent with shigellosis, and Shigella flexneri 6, Boyd 88 biotype, was isolated from rectal swabs taken from 8 to 35 ill passengers and 33 of 294 crew members. Epidemiologic evidence incriminated the ship's water, including ice, as the probable vehicle of transmission, and elevated coliform counts were found in potable water samples obtained aboard the vessel at the peak of the outbreak. Potential sources of contamination of the vessel's potable water supply were investigated, and improvements in the loading and chlorination of potable water were recommended.

The first naturally acquired case of cholera reported in the United States since 1911 occurred in a 51-year-old resident of Port Lavaca, Texas. Extensive epidemiologic investigation of the patient's contacts and environment did not identify a cholera carrier of elucidate a pathway of transmission, but several avenues of investigation suggested possible means by which the patient may have acquired his infection. No secondary spread resulted from this case, and its occurrence did not endanger the community at large.

Bender, T. R. (CDC, 225 Eagle St., Anchorage, Alaska 99501), T. S. Jones, W. E. DeWitt, G. J. Kaplan, A. R. Saslow, S. E. Nevius, P. S. Clark and E. J. Gangarosa. Salmonellosis associated with whale meat in an Eskimo community. Serologic and bacteriologic methods as adjuncts to an epidemiologic investigation. Am J Epidemiol 96: 153–160, 1972.—In August 1969, an outbreak of Salmonella enteritidis gastroenteritis occurred in Tununak, Alaska, a small Eskimo village on the Bering Sea. Illness histories obtained from all 265 villagers revealed that 105 persons had symptoms compatible with salmonellosis for an overall attack rate of 40%. Symptoms consisted of fever, chills, nausea, vomiting, cramps, and diarrhea. Of the 99 persons who ate whale meat, 93( 94%) became ill. S. enteritidis was cultured from samples of the meat. Rectal swabs randomly collected from 135 persons were positive for S. enteritidis in 65 (48%) of the cases. Of the 17 villagers hospitalized, all had positive stools and three had positive blood cultures. A comparative study of three stool transport media one month after the start of the epidemic yielded positive isolations as follows: Hajna's (12%), Cary-Blair (17%), and tetrathionate (18%). A bacterial agglutination test was particularly useful in the retrospective evaluation of the epidemic and fourfold rises in antibody titer correlated well with clinical and bacteriologic findings.

Fecal specimens for culture of Vibrio cholerae may be transported to the laboratory with the expectation of a high rate of recovery, depending on the type of transport medium used. Alkaline, bile-salt, tellurite peptone broth has proved to be the method of choice at the Pakistan-SEATO Cholera Research Laboratory. This medium is ideal for transporting specimens from field to laboratory and for short-term enrichment. Other media are also useful, especially if long delays are anticipated; in this study, alkaline, bile-salt peptone broth with tellurite-impregnated swabs, Cary-Blair medium, and the sea-salt medium of Venkatraman and Ramakrishnan maintained V. cholerae as long as 4 weeks. Buffered glycerol saline solution proved too inhibitory for either short-term or long-term holding.

Eugene J. Gangarosa, Wallis E. DeWitt, John C. Feeley, and Mary R. Adams From the Epidemiology Program, National Communicable Disease Center, Health Services and Mental Health Administration, Public Health Service, U.S. Department of Health, Education, and Welfare, Atlanta, Georgia; and the Division of Biologies Standards, National Institutes of Health, Public Health Service, U.S. Department of Health, Education, and Welfare, Bethesda, Maryland

Microtiter hemagglutination tests employing formalinized sheep erythrocytes sensitized with either crude or purified cholera toxin were used to assay the cholera antitoxin content of human sera. Comparable results were obtained with either crude or purified toxin-sensitized cells with the exception of two sera that gave unusually high hemagglutination titers with the crude toxin. Sera from 13 convalescent cholera patients showed a high degree of correlation between antitoxin levels as determined in vitro by the hemagglutination test and in vivo by the skin permeability factor neutralization test. Fourfold or greater rises in antitoxin levels between acute and convalescent sera were detected in 9 of 15 patients with bacteriologically proven cholera. No significant increases in titer were observed in 14 cases of noncholera diarrhea. Cholera antitoxin was detected by hemagglutination in only 1 of 33 sera, obtained from eight countries, containing vibriocidal antibodies. Formalinized sheep erythrocytes sensitized with toxin and stored at 4 C in the presence of 1:10,000 thimerosal were stable and sensitive for at least 6 months (the longest time tested).

TCBS medium has been shown to be as effective as two other widely used and well established media for isolating Vibrio cholerae. This study gives an objective basis for using a simplified isolation method that has already found wide acceptance in a large part of the infected and threatened areas of the world. There are important implications for cholera surveillance.

Epidemic of febrile gastroenteritis due to Salmonella java traced to smoked whitefish. E J Gangarosa, A L Bisno, E R Eichner, M D Treger, M Goldfield, W E DeWitt, T Fodor, S M Fish, W J Dougherty, J B Murphy, J Feldman, and H VogelCopyRight https://doi.org/10.2105/AJPH.58.1.114 Published Online: August 29, 2011