Kenneth L. Vosti

Gal-Gal binding and hemolysin phenotypes and genotypes associated with uropathogenic Escherichia coli

To determine whether uropathogenic strains of Escherichia coli exhibit a distinctive constellation of phenotypes, we examined 44 urinary isolates from women with radiologically normal urinary tracts and pyelonephritis, cystitis, or asymptomatic bacteriuria and 73 fecal isolates from healthy control subjects. The strains were characterized by their O serogroup, by their binding specificity (as determined by adhesins), and by their production of hemolysin and colicin V. In addition, the strains were assessed for homologous gene sequences by means of DNA-hybridization probes prepared from cistrons that encode hemolysin and the Gal-Gal binding adhesin--two determinants of virulence, which cause tissue injury and promote bacterial colonization of uroepithelia, respectively. In contrast to most isolates from normal feces and from the urine of patients with asymptomatic bacteriuria, pyelonephritis strains belong to a small number of O serogroups; all express the Gal--Gal binding adhesin and 75 per cent are hemolytic. A gene probe for the Gal--Gal binding adhesin, derived from the chromosome of one strain from a patient with pyelonephritis, hybridized with the DNA of all other pyelonephritis strains. The probe for the hemolysin gene hybridized with DNA from all other hemolytic strains. These data indicate that most cases of pyelonephritis are due to a small number of pathogenic clones that express critical determinants of virulence, and that the nucleotide sequences for hemolysin and the Gal--Gal binding adhesin in heterologous strains share homology. We are tempted to speculate that the gene products of these shared regions of the genome might form the basis for a vaccine against pyelonephritis.

Bacterial infections in pediatric Hodgkin's disease. Relationship to radiotherapy, chemotherapy and splenectomy

The occurrence of bacterial infections (B.I.) among 181 children with Hodgkins disease (121 with splenectomy, 60 without splenectomy) was analyzed. Twenty‐seven B.I. occurred among 22 children and included 15 episodes of bacteremia‐meningitis in 14 children. B.I. occurred in all age groups, but bacteremia‐meningitis occurred most commonly in splenectomized children 10 years of age or less. The frequency of B.I. in splenectomized children receiving radiotherapy was 1.4%, compared to 18.3% among those receiving chemotherapy (p < 0.05). the frequency of B.I. among non‐splenectomized children receiving radiotherapy was 2.8%, compared to 23.1% among those receiving chemotherapy (p < 0.05). There was no difference in the probability of B.I. as a function of splenectomy for the corresponding groups, although all cases of streptococcus pneumoniae and hemophilus influenzae bacteremia‐meningitis in splenectomized children. Overwhelming postsplenectomy bacteremia infection not related to active disease or treatment occurred in 3/121 (2.5%) children, accounting for only one fatality (0.8%).

Characterization of Postsplenectomy Bacteremia among Patients with and without Lymphoma

Abstract The medical records of 494 patients who underwent splenectomy, including 269 patients with lymphoma, were analyzed for the occurrence of postsplenectomy bacteremia. Twenty-three episodes of bacteremia were identified among patients in the nonlymphoma group, and 12 episodes in the lymphoma group. Five cases of pneumococcal bacteremia were identified, and all occurred in patients with lymphoma. The fatality rate did not differ among patients with or without lymphoma in whom bacteremia developed after splenectomy. The findings do not indicate that splenectomy alters the fatality rate in patients with serious associated disease in whom bacteremia subsequently develops.

Factitious and fraudulent fever

The task of elucidating the etiology of fever of undertermined origin remains a major undertaking. Factitious fever is uncommonly considered of major importance in the differential diagnosis of fever of undetermined origin although it is a readily identifiable, syndrome and one that is easily excluded one it has been considered. Early identification may reduce the necessity for prlonged, expensive and potentially hazardous hospitalizations for such patients. A retrospective study identified 2.2 per cent (11 of 506) of all patients whose fever on their charts was coded as fever of undetermined origin as having factitious fever. These patients either created factitious fever by manipulation of the thermometer or fraudulent fever by self-induced means. A review of the literature yielded an additional 70 cases in which fever was either the sole factitious sign or part of a larger, more complex factitious illness. Patients were typically young, female and often associated with the medical profession. Patients with factitious fever differ from those with the stereotyped Munchausens syndrome and may be difficult to recognize. Signs leading to the recognition of this syndrome are emphasized. Since the nature of the psychiatric illness may vary from patient to patient, early discovery may facilitate psychiatric intervention as such patients may be more amenable to therapy.

Prosthetic Valve Endocarditis Caused by Legionella pneumophila

Prosthetic valve endocarditis due to Legionella pneumophila occurred in a woman who had aortic and mitral valve replacements with porcine xenografts. During surgery for persistent fever and aortic regurgitation due to presumed endocarditis, she had vegetations involving both the aortic and mitral valve prostheses with a circumferential abscess of the aortic annulus. Cultures, Dieterle stain, and direct fluorescent antibody stain of valve tissue, and subsequent measurements of serum antibody levels confirmed L. pneumophila as the infecting organism. This infection occurred in the absence of pneumonia. Legionella pneumophila must be considered a potential cause of culture-negative prosthetic valve endocarditis and should be sought in appropriate clinical circumstances.

The importance of sample size in studies based upon the serologic classification of escherichia coli.

Summary The total number of different serological O groups in individual specimens was determined by a study of Escherichia coli isolated from feces, urines, the vagina, and blood. The serologic heterogeneity of the fecal coliform flora was confirmed. Ninety percent of urines contained only a single E. coli group regardless of the number of organisms present. The vaginal flora was composed of a single group less frequently than the organisms isolated from urine, but was not so heterogenous as that of the feces. E. coli recovered from blood was invariably of a single group. The importance of sample size was demonstrated in the study of stool specimens. Most O groups present were identified by an examination of only 5 colonies but the possibility of identifying additional strains was not exhausted by a study of as many as 25 colonies. The chances of finding new O groups by a study of more than 5 colonies were greater in those specimens that initially contained more than one O group.

Elution of Glomerular Bound Antibodies in Experimental Streptococcal Glomerulonephritis

lmmnunoglobulin G, eluted from glomeruli of rats with streptococcal glomerulonephritis, reacts with type 12 M protein of the streptococcus but not with other streptococcal or renal antigens. Thtrefore, this disease may be madiated by fixation of antigen-antibody complexes consisting of streptococcal M protein and type-specific antibody.

Arizona hinshawii Infections: New Cases, Antimicrobial Sensitivities, and Literature Review

Although disease caused by Arizona hinshawii is known to resemble the spectrum of clinical syndromes seen with Salmonella infections, little is known of their sensitivity to antimicrobials. We present three cases that are illustrative of Arizona sepsis, localized infection, or both; review the literature; and report sensitivities to 12 antimicrobials for 32 human and animal isolates of Arizona hinshawii from various geographic areas. With the exception of erythromycin and streptomycin, most strains were sensitive to many of the commonly used antibiotics. As with Salmonella infections, ampicillin or chloramphenicol appear to be the initial antimicrobial agents of choice for severe infections with A. hinshawii. Definitive antimicrobial therapy must be individualized on the basis of sensitivity testing and with regard to host factors.

Uropathogenic Escherichia coli: molecular mechanisms of adherence.

Escherichia coli isolated from endogenous infections of the urinary tract usually originate in the colon (1–3). From the stool, uropathogenic strains colonize the vaginal introitus and periurethral region (4). Colonization of uroepithelium may ensue, leading to bacteriuria. Symptoms arise when invasion of mucosa, cell death, and inflammation occur in the bladder or kidney. Therefore, cystitis and pyelonephritis may be viewed as the culmination of a sequence of events mediated by specific determinants of microbial virulence. It follows that uropathogenic E. coli are not simply the most prevalent fecal stains. Instead, they appear to manifest a pathogenic phenotype: they usually belong to a restricted number of O and K antigen serogroups (3–5); they are resistant to the bactericidal action of normal human serum (6–8); they secrete hemolysin (9–11), produce colicin V (12–13), and ferment salicin (14); and they attach to uroepithelial cells in vitro (15–17).

Host-Parasite Interaction among Infections Caused by Escherichia Coli.

Excerpt The ability to serologically identify some 140 different O groups has greatly facilitated the study of host-parasite interaction with infections due to E. coli. We studied 277 patients with...