Tularemia in a mule deer.

A case of tularemia was confirmed in a 51-year-old man who acquired the disease from a mule deer, Odocoileus hemionus. Francisella tularensis was isolated from bone marrow of the deer carcass.

Yersinia enterocolitica isolates from humans in California, 1968-1975.

This paper reports on the serological and biochemical characteristics of 24 human isolates of Yersinia enterocolitica submitted to the California Department of Health from 1968 through 1975. Nine different serotypes were represented. The majority of strains were serotype O:8 (six strains) and serotype O:5 (five strains). Sources of the isolates included feces (12 cases), blood (3), sputum or throat (3), bile or bowel drainage (2), wounds (2), breast abscess (1), and skin abscess (1). Clinical histories indicated a number of different syndromes. Underlying medical conditions existed in 13 cases. Results of selected biochemical tests and antimicrobial susceptibility tests on the strains indicated grouping compatible with the O serotypes of the organisms.

Yersiniosis in California.

Thirty-three strains of Yersinia enterocolitica representing 11 different serotypes were identified from human isolates in California between 1968 and mid-1977. The most frequently encountered serotype, 0:5,27, was identified in 8 cases. Twenty-one strains, representing five serotypes, were esculin- and salicin-negative, and were considered to be the primary cause of disease in the majority of these cases. The remaining strains, representing six serotypes, were esculin- and salicin-positive, and appeared to be 'opportunistic' organisms. They were isolated from 12 patients, 8 of whom had underlying conditions, and 4 or whom were asymptomatic. From 1968 to 1977, 13 strains of Y. pseudotuberculosis isolated from humans were submitted to our laboratory for identification or confirmation. Ten were serotype I and three, serotype III. Sources of isolation included blood (6); blood and liver abscess (1); blood and urine, and liver at autopsy (1); feces (2); biopsy of terminal ileum (1); abdomonal abscess (1); and neck abscess (1). The results of serotyping and biochemical characteristics of the strains, as well as the clinical histories of the patients, are discussed.

Characterization of Borrelia burgdorferi strains isolated from Ixodes pacificus ticks in California.

In a survey of 1,714 adult Ixodes pacificus ticks collected in northern California, 24 (1.4%) were found to be infected with spirochetes that reacted with an anti-Borrelia burgdorferi polyvalent conjugate in direct immunofluorescence tests. Eleven isolates of B. burgdorferi from these ticks were characterized by monoclonal antibody, polyacrylamide gel electrophoresis, and Western blot (immunoblot) analyses. Ten of the isolates had molecular and antigenic characteristics similar to those of other U.S. isolates. One strain, cloned by limiting-dilution techniques, was different from any previously reported U.S. strain, but similar to reported European strains. The cloned strain, DN127-Cl9-2, did not react with monoclonal antibodies to Osp A and Osp B major proteins found in most of the U.S. strains. It exhibited an abundant protein with an apparent molecular weight of 25,000.

Development of antigens in human cells infected with Simian virus 40.

Bissett, Marjorie L. (University of Michigan, Ann Arbor), and Francis E. Payne. Development of antigens in human cells infected with simian virus 40. J. Bacteriol. 91:743-749. 1966.-An explanation for the apparent infrequency with which human cells transform in response to exposure to simian virus 40 (SV40) was sought by following the development of virus-induced antigens in human euploid cells, strain CR. For about 8 weeks after exposure to a high multiplicity of SV40, only a small proportion of the cells produced tumor (T) or viral (V) antigen detected by immunofluorescence. Double-tracer staining techniques revealed that the development of T and V antigen in about 1% of the CR cells resembled that in green monkey kidney cells, strain BS-C-1, in which SV40 replicates and destroys all the cells. T antigen was detected before V antigen; both antigens were detected in the nucleus, but only V antigen appeared later in the cytoplasm. All intact cells that contained V antigen also contained T antigen. Infected CR cell cultures, before and after transformation or when in "crisis," contained only 0.1 to 1.0% of cells with both V and T antigen. Some CR cells contained only T antigen, and by 8 days after exposure to virus these cells were present as loose foci associated with an occasional cell containing V antigen. The proportion of CR cells with only T antigen increased from about 1% during the first 4 weeks to 8% at 7 weeks, and to nearly 100% at 11 weeks, when essentially all of the cells were epithelioid. Foci of epithelioid cells were first recognized in the 9th week. It was concluded that those CR cells that contained T antigen at any given time represented (i) a few cells that subsequently produced V antigen and lysed, and (ii) a progressively increasing population that produced only T antigen. If the latter population, in whole or in part, gave rise to the epithelioid transformed cells, then its initial size could account, at least in part, for the apparent infrequency with which human cells transform in response to SV40.

Antimicrobial resistance and R factors in Salmonella isolated in California (1971-1972).

The antimicrobial resistance of 2,246 strains of Salmonella isolated from humans in California was determined. Resistance to one or more of the 12 antimicrobial agents tested was found in 32% of the isolates. Salmonella typhimurium strains represented 31% of the serotypes isolated; 49% of these strains were resistant. Fifty-one percent of S. heidelberg, 42.5% of S. newport, and 40% of S. saint paul strains were resistant. Seventy-seven percent of all resistant serotypes were resistant to two or more of the antimicrobial agents tested. R factors were demonstrated in 70% of the multiply resistant strains. Resistance of the Salmonella strains to one or more of the 12 antimicrobials tested and the frequency of resistance to tetracycline and ampicillin were significantly greater than resistance reported in other studies performed in this country. Chloramphenicol resistance was encountered in 33 (1.5%) of the Salmonella isolates; 19 of these were S. typhi demonstrating a pattern of resistance to streptomycin, sulfisoxazole, tetracycline, and chloramphenicol and carrying an R factor capable of transferring the complete pattern of resistance.

New serogroup of Legionella pneumophila, serogroup 8.

A strain of Legionella pneumophila (designated Concord 3) was isolated from a postmortem lung specimen of a patient with pneumonia. Direct fluorescent-antibody and immunoelectrophoresis tests, using absorbed and unabsorbed reagents prepared to this and other strains of legionellae, indicated that the Concord 3 strain represents a new serogroup of L. pneumophila, serogroup 8.

Immunofluorescent identification of Salmonella typhi during a typhoid outbreak.

Immunofluorescence and conventional bacteriological methods were compared for their ability to detect Salmonella typhi in 134 fecal specimens from 105 individuals associated with an outbreak of typhoid fever. Smears prepared from untreated fecal material (direct method) and after a preliminary incubation in selenite F broth (delayed method) were tested with an anti-Vi serum conjugated with fluorescein isothiocyanate. The delayed method was more sensitive than the direct method in detecting S. typhi. The delayed method was positive in 40 of 41 patients positive by culture methods, but gave positive or questionable reactions in 11 presumably uninfected individuals. The fluorescent-antibody test employing a Vi conjugate is a satisfactory screening procedure for detecting S. typhi, but all positives must be confirmed bacteriologically.

Laboratory identification of aeromonads from man and other animals.

Forty-eight isolates of aeromonads from clinical specimens were studied. The laboratory procedures employed and the results obtained are reported in the hope that they may be of assistance to other workers in the field of diagnostic microbiology. Capability of identifying these organisms in the laboratory will contribute to a better understanding of the role of this group of organisms in human disease as well as in diseases in other animals.

Epidemiologic investigations of Yersinia enterocolitica and related species: sources, frequency, and serogroup distribution.

During an 11-year period (1978 to 1989), over 300 strains of Yersinia spp. (excluding Y. pestis and Y. pseudotuberculosis) were recovered from a variety of gastrointestinal and extraintestinal sites in patients in California. Over the 11-year period, Y. enterocolitica serogroup O:3 predominated, although a shift in the relative frequency of this serogroup was observed during this interval, increasing dramatically during the years 1984 to 1989. Of the remaining Y. enterocolitica isolates, over 40% were identified as belonging to serogroups generally considered to be nonpathogenic, although many of these isolates were recovered in association with milder cases of gastroenteritis. The results suggest a changing and expanding spectrum of Y. enterocolitica serogroups associated with various gastrointestinal and systemic infections.

Legionella longbeachae species nova, another etiologic agent of human pneumonia.

A new species of bacteria that is an etiologic agent of human pneumonia has been isolated and characterized. Clinical symptoms of infection with this organism are not readily distinguishable from those caused by Legionella pneumophila infection. The organism was isolated from respiratory tract specimens from four patients. Two cases of infection apparently originated in California and one in Georgia, and a fourth was of unknown geographic origin. The name Legionella longbeachae species nova is proposed for this organism. The type strain of L. longbeachae is Long Beach 4 (= American Type Culture Collection 33462).

Chloramphenicol-resistant Salmonella newport traced through hamburger to dairy farms. A major persisting source of human salmonellosis in California.

Animal-to-human transmission of drug-resistant salmonella and the role of antimicrobial use in food animals in the emergence of these bacteria are controversial subjects. Investigation of a 4.9-fold increase in Salmonella newport isolations from Californians in 1985 showed that 87 percent of the isolates had an unusual antimicrobial-resistance pattern (including chloramphenicol resistance) and a single, identical plasmid. Interviews of 45 patients and 89 matched controls in Los Angeles County showed that illness was associated with penicillin or tetracycline use during the month before onset (P less than 0.001) and with eating ground beef during the week before onset (P = 0.052). The epidemic strain was isolated from hamburger products eaten by cases, abattoirs where the animals from which the meat came were slaughtered, dairies that sent cows for slaughter on days when culture-positive products were processed, and ill dairy cows. Isolation of salmonella from beef carcasses in abattoirs correlated with the proportion of dead or moribund animals received for slaughter (r = 0.60, P less than 0.05). Isolation of chloramphenicol-resistant salmonella from dairy farms was associated with the use of chloramphenicol at those dairies. We conclude that food animals are a major source of antimicrobial-resistant salmonella infections in humans and that these infections are associated with antimicrobial use on farms.

Molecular epidemiology of antibiotic resistance in salmonella from animals and human beings in the United States.

We collected serotyped isolates of salmonella from reference laboratories in the United States, tested their susceptibility to antibiotics, and extracted plasmids from isolates that were resistant to a different combination of antibiotics from each of three serotypes. Restriction-endonuclease digestion showed that within each of the three groups, plasmid molecules from animal and human isolates were often identical or nearly identical. One serotype-plasmid combination appeared to be endemic in cattle in 20 states and infected 26 persons in two states. The human cases, which were not recognizably related except for their common plasmids, appeared to be clustered in time but geographically dispersed, like cases in previous outbreaks spread by food products. These findings suggest that resistance plasmids may be extensively shared between animal and human bacteria, and that spread of multiresistant strains of salmonella among animals and human beings, as observed in Britain, may have been undetected in the United States for lack of comparable surveillance.