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AbstractArticulated sensilla occur on the pronotum of 100 species in 65 genera of membracids. The abundance of the sensilla and their universal occurrence in this group suggests that sensory reception is a significant function of the membracid pronotum. Bizarre forms of the pronotum may be a result of selection pressure to increase surface area.

An outbreak of gastroenteritis occurred in March-April 1981, in Wichita, Kansas, and involved more than 250 persons who drank raw milk from a single local dairy. Campylobacter jejuni was recovered from 60 of 116 (52%) persons in households that had one or more ill family members. A cohort study of families that belonged to a food cooperative that purchased raw milk from the implicated dairy showed a significant association between illness and having drunk raw milk. Thirty-nine of 55 (71%) persons who drank raw milk became ill compared with four of 36 (11%) persons who did not drink raw milk (p less than 0.01, t test, accounting for clustering). Peak (convalescent) antibody titers to C. jejuni, determined by indirect immunofluorescence, in 20 raw-milk drinkers showed a geometric mean of 1:27 in contrast to geometric mean titer of 1:6 in 10 well persons from the cohort who did not drink raw milk (p less than 0.002, t test). C. jejuni was recovered from 21 of 34 (66%) raw-milk drinkers, versus none of 26 people who did not drink raw milk (p less than 0.001, Fisher's exact test, one tailed). C. jejuni of the same serotype was isolated from the case-patients and from rectal swabs of cows in the dairy. These findings indicate that raw milk contaminated by Campylobacter was the vehicle for this outbreak.

A selective medium was developed and used successfully to isolate Legionella pneumophila and Legionella-like organisms from environmental specimens previously positive by animal inoculation methods. This medium consists of charcoal-yeast extract agar to which have been added cephalothin (4 micrograms/ml), colistin (16 micrograms/ml), vancomycin (0.5 microgram/ml), and cycloheximide (80 micrograms/ml). Pretreating of the environmental water samples with an acid buffer (pH 2.2), followed by plating on the selective medium, improved the rate of recovery of both Legionella and Legionella-like organisms relative to that with direct plating on selective media.

The Vibrio-like organism EF-6 was isolated from more than 500 patients with diarrhea in Bangladesh between October 1976 and June 1977. Bacteriological studies indicate that EF-6 is a member of the family Vibrionaceae and that it should be provisionally placed in the genus Vibrio. EF-6 was isolated from patients who had diarrhea, but was not conclusively implicated as the etiological agent. Pending further study, EF-6 should be considered a potential enteropathogen.

The Moore swab method was shown to be a practical and sensitive technique for the isolation of Vibrio cholerae from sewage. In each of three instances in which cholera patients lived in homes connected to municipal sewers, V. cholerae was isolated from the community sewage plant intake at the time of the patients illness. Sewer systems became negative within 1 day after patients were treated with tetracycline. Sewer surveillance using the Moore swab also found evidence of infections occurring in areas where surveillance of diarrheal illness failed to detect cholera. Culturing community sewage by the Moore swab method proved to be an economical and effective way of determining areas where V. cholerae infections were occurring.

The test for hippurate hydrolysis is critical for separation of Campylobacter jejuni and C. coli strains. Glycine and benzoic acid are formed when hippurate is hydrolyzed by C. jejuni. The test used in most laboratories is one of several variations of the ninhydrin tube test described by Hwang and Ederer (M. Hwang and G. M. Ederer, J. Clin. Microbiol. 1:114-115, 1975) for detection of glycine. We evaluated three modifications of the Hwang and Ederer method and the gas-liquid chromatographic (GLC) method described by Kodaka et al. (H. Kodaka, G. L. Lombard, and V. R. Dowell, Jr., J. Clin. Microbiol. 16:962-964, 1982) for detecting benzoic acid. Campylobacter strains comprised 22 C. jejuni, 11 C. coli, and 8 C. laridis strains. The species identification of each strain was confirmed by DNA relatedness. All strains of C. jejuni were positive and all strains of C. coli and C. laridis were negative by the GLC method for detecting hippurate hydrolysis, whereas three strains of C. jejuni gave negative or variable results in the tube tests. The GLC method is more sensitive than the tube methods for detecting hippurate hydrolysis and should be used on cultures yielding variable or questionable test results.

We compared two Campylobacter serotyping systems by using 1,405 isolates of Campylobacter collected from human, animal, and environmental sources during epidemiologic investigations and special studies. We found 96.1% of isolates to be typable by the Penner method for heat-stable antigens, which involved the use of an indirect hemagglutination technique, and 92.1% of isolates to be typable by the Lior method for heat-labile antigens, which involved the use of a slide agglutination technique and absorbed antisera. Absorbed antisera were not required for the Penner method, making that method less difficult to implement. The Lior method was simpler to perform and gave more rapid results than did the Penner method. Cultures frequently reacted in multiple antisera with the Penner method, whereas multiple reactions were rare with the Lior method. Thus, results were easier to interpret with the Lior system. Strains of a single serotype in one system were sometimes found to be multiple serotypes in the other system; hence, the two methods have the potential to be complementary. Both systems were comparable in serotyping isolates from human and nonhuman sources and for evaluating the relationship of strains collected during outbreak investigations.

Two outbreaks of hemorrhagic colitis, a newly recognized syndrome characterized by bloody diarrhea, severe abdominal pain, and little or no fever, occurred in 1982. No previously recognized pathogens were recovered from stool specimens from persons in either outbreak. However, a rare E. coli serotype, O157:H7, was isolated from 9 of 20 cases and from no controls. It was also recovered from a meat patty from the implicated lot eaten by persons in one outbreak. No recovery of this organism was made from stools collected 7 or more days after onset of illness; whereas 9 of 12 culture-positive stools had been collected within 4 days of onset of illness. The isolate was not invasive or toxigenic by standard tests, and all strains has a unique biotype. Plasmid profile analysis indicates that all outbreak-associated E. coli O157:H7 isolates are closely related. These results suggest that E. coli O157:H7 was the causative agent of illness in the two outbreaks.

Two brands of thiosulfate citrate bile salts sucrose agar and Monsur taurocholate tellurite gelatin (TTG) agar were compared with two newly developed media, sucrose tellurite teepol agar and Vibrio parahaemolyticus agar for isolation and identification of Vibrio cholerae. The thiosulfate citrate bile salts sucrose and TTG agars were the best selective media, whereas sucrose tellurite teepol agar was the poorest. Both TTG and sucrose tellurite teepol agars were good for use in follow-up serological tests, whereas only TTG agar could be used for follow-up oxidase tests. In our opinion TTG agar has more advantages for cholera research laboratories routinely culturing large numbers of patients for cholera on a daily basis and where media needs can be accurately predicted. In contrast, in smaller clinical laboratories or in laboratories investigating epidemics, thiosulfate citrate bile salts sucrose agar is best because it is commercially available and easy to prepare and can be used to distinguish colonies of suspect V. cholerae from V. parahaemolyticus.

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.

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.

To evaluate the usefulness of the indirect hemagglutination (IHA) test in the epidemiological investigation of shigellosis, single serum specimens were tested from 50 patients with Shigella dysenteriae 1 (Shiga bacillus) infections, 103 asymptomatic contacts of these cases, 267 adult and 100 student control, and serum specimens collected during two outbreaks caused by S. sonnei and one outbreak due to S. flexneri 6. In patients with S. dysenteriae 1, 74% demonstrated titers of greater than or equal to 1:40, with 50% showing titers of greater than or equal to 1:160, whereas in the controls 10.4% had titers of greater than or equal to 1:40 and only 0.3% had titers of greater than or equal to 1:160. IHA titers in serum specimens collected from patients with S. sonnei and S. flexneri 6 were too low to be considered diagnostic for individual patients, but were useful in analysis of group results. Groups of ill individuals yielded titers significantly higher than non-ill groups; however, titers from ill groups were usually less than 1:40. The IHA test for S. dysenteriae 1 antibodies serves as a valuable adjunct to the diagnosis of Shiga bacillus dysentery. In our laboratory, an IHA titer of 1:40 or 1:80 is a "borderline positive." Shiga bacillus dysentery is strongly indicated when IHA titers are greater than or equal to 1:60.

During a 2-year period, 14 biochemically atypical Campylobacter fetus subsp. fetus-like strains were received by the Campylobacter Reference Laboratory at the Centers for Disease Control. Sources of the isolates were blood, nine strains; stools, two strains; amniotic fluid, one strain; and abscesses, two strains. Atypical phenotypic characteristics exhibited by one or more strains were growth at 42 degrees C, 10 strains; no H2S by lead acetate paper, 3 strains; resistance to a 30-micrograms cephalothin disk, 2 strains; and nonmotility, 1 strain. By DNA-DNA hybridization, all 14 isolates and the type strain of C. fetus subsp. fetus (ATCC 27374) were 94 to 100% related in reassociation reactions at 50 degrees C, with 0.0 to 0.5% divergence, and were 86 to 100% related in reassociation reactions at 65 degrees C. Thus, all of these atypical strains were C. fetus subsp. fetus. MICs of 11 antimicrobial agents for these 14 strains were variable. All strains were susceptible to chloramphenicol, erythromycin, gentamicin, and tetracycline, and most were susceptible to ampicillin, clindamycin, and penicillin. Eleven strains were resistant to cephalothin (MIC greater than or equal to 16 micrograms/ml), nine were resistant to rifampin (MIC greater than or equal to 8 micrograms/ml), and all were resistant to nalidixic acid (MIC greater than 32 micrograms/ml) and vancomycin (MIC greater than 32 micrograms/ml). One can expect to see biochemical variability in C. fetus subsp. fetus strains and to encounter such strains from a variety of human sources, the most important of which appears to be blood.

No new serotypes have been added to the Shigella schema since 1958, although several provisional serotypes have been described. We conducted biochemical and serological studies on three provisional Shigella boydii serotypes. Four strains of serotype 2710-54 from four widely separated countries, 7 strains of serotype 3615-53 from three different countries, and 31 strains of serotype 1344-78 (E10163) from six different countries were included. Reactions of all three serotypes were consistent with those of S. boydii. On the basis of these results and other published research, we propose that these three provisional serotypes be admitted to the Shigella schema as S. boydii 16, 17, and 18.

In August 1974, six cases of cholera occurred on Guam. The index case had severe diarrhea and metabolic acidosis and died from pneumonia on the ninth day of illness; the other five cases had only mild to moderate diarrhea. Fish caught in Agana Bay and home-preserved was found to be the vehicle most likely responsible for the cases. Vibrio cholerae, El Tor Ogawa, was isolated from two patients, the Guam sewerage system, and a river emptying into Agana Bay. V. cholerae, El Tor Inaba, was isolated from the sewerage system, three storm drains imptying into Agana Bay, and Agana Bay. The Ogawa and Inaba isolates differed in their sucrose fermentation and hemolysis reactions, phage type and ability to produce toxin. Although this was the first reported cholera outbreak on Guam, the isolation of differentV. cholerae strains suggested that multiple introductions of V. cholerae had occurred on the island.