Biomedical subjects

P S Hayes

Publications and source records attributed to P S Hayes.

At least 19 recordsLinked to original sources

PubMed1995

Listeria monocytogenes infection and serotype distribution among HIV-infected persons in Los Angeles County, 1985-1992.

Persons infected with human immunodeficiency virus (HIV) are at greater risk of infection with Listeria monocytogenes (LM) than the general population. We quantify the risk of listeriosis in persons with acquired immune deficiency syndrome (AIDS) and HIV infection in Los Angeles County (LAC) and report the LM serotype distribution among HIV-infected patients with listeriosis. Active surveillance for listeriosis was performed in LAC during most of the period from 1985 through 1992. Thirty-four (10%) of 351 nonperinatal cases of listeriosis reported in LAC from 1985 through 1992 were in HIV-infected persons, 25 of whom met the 1987 AIDS case definition. The incidence of listeriosis was 95.8 and 8.8 cases per 100,000 person-years among persons with AIDS and all HIV-infected persons, respectively, but only 1.0 case per 100,000 person-years in the total population. Excluding cases from a 1985 listeriosis epidemic associated with consumption of contaminated Mexican-style cheese, 11 (65%) of 17 HIV-infected persons with available isolates were infected with LM serotype 1/2b, whereas only 64 (31%) of 208 other persons with listeriosis and available isolates were infected with LM serotype 1/2b (odds ratio = 4.1; 95% confidence interval = 1.3-14.1). LM serogroup 1/2b may have been more common among HIV-infected persons in LAC than among other persons with listeriosis because of differences in diet or sexual practices, or to chance alone. Persons with HIV-infection, especially those with AIDS, should be educated in avoiding foods at high risk of listerial contamination, such as soft cheeses, foods sold from delicatessen counters, and undercooked chicken.

Adolescent↗

PubMed1992

Role of foods in sporadic listeriosis. II. Microbiologic and epidemiologic investigation. The Listeria Study Group.

OBJECTIVE: To evaluate the role of foods in sporadic listeriosis. DESIGN: Microbiologic survey of foods collected from refrigerators of patients with listeriosis identified through active laboratory-based surveillance. Patient and food Listeria monocytogenes isolates were subtyped to identify foods contaminated with the same strain of L monocytogenes that caused illness in the patient; samples of these foods were obtained from the retail source. SETTING: Multistate population-based study conducted between 1988 and 1990. RESULTS: Listeria monocytogenes grew from at least one food specimen in the refrigerators of 79 (64%) of 123 listeriosis patients; 11% of more than 2000 food specimens collected in the study contained L monocytogenes. Twenty-six (33%) of 79 refrigerators with foods that grew L monocytogenes contained at least one food isolate of the same strain as that in the corresponding patient, a frequency much higher than would be expected by chance (P less than .001). Multivariate analysis showed that of the food specimens that grew L monocytogenes, foods that were ready-to-eat, foods that grew L monocytogenes by a direct-plating method (a measure of the level of contamination), and foods that contained serotype 4b isolates were independently associated with an increased likelihood of containing the patient-matching strain. CONCLUSION: We identified specific food and L monocytogenes isolate characteristics--ready-to-eat foods, foods containing higher concentrations of L monocytogenes, and foods containing serotype 4b--which were associated with disease-causing strains. These results can provide guidance to industry and regulatory agencies in developing strategies to prevent listeriosis.

Food↗

PubMed1991

Comparison of cold enrichment and U.S. Department of Agriculture methods for isolating Listeria monocytogenes from naturally contaminated foods. The Listeria Study Group.

We compared the cold enrichment (CE) and U.S. Department of Agriculture (USDA) methods for isolating Listeria monocytogenes by examining 402 food samples. The food samples were collected from refrigerators of listeriosis patients as part of a multistate active surveillance project to determine the role of foods in sporadic listeriosis in the United States. L. monocytogenes was isolated from 51 food samples (13%). The USDA method was significantly better (P less than 0.001) than the CE method. The isolation efficiencies of the USDA and CE methods were 96 and 59%, respectively. Quantitation of L. monocytogenes in the food samples revealed that many food samples containing less than 0.3 CFU/g were negative as determined by the CE method but positive as determined by the USDA method.

Cold Temperature↗

PubMed1989

Investigation of an outbreak of listeriosis: new hypotheses for the etiology of epidemic Listeria monocytogenes infections.

From December 1986 to March 1987 an outbreak of Listeria monocytogenes infection occurred in the Philadelphia metropolitan area. A patient-control study showed patients were more likely than controls to have had an ill family member and to have used antidiarrheal medication during the month before their illness. Diet histories showed patients were significantly more likely to have eaten ice cream or salami than were controls, and to have shopped at one grocery store chain. Subtyping of L. monocytogenes isolates of patients showed no predominant strain, and cultures of food products eaten by patients were negative except for Brie cheese eaten by one patient. With no predominant strain of L. monocytogenes in the patients, a common source for this outbreak is unlikely. Thus, the identified risk factors may have been associated with carriage of L. monocytogenes and a coinfecting organism may have precipitated disseminated disease. Possible cofactors should be considered in investigations of future outbreaks of listeriosis.

Adolescent↗

PubMed1987

Commercial latex agglutination tests for detection of Haemophilus influenzae type b and Streptococcus pneumoniae antigens in patients with bacteremic pneumonia.

The validity of commercial latex agglutination kits for detection of Haemophilus influenzae type b and Streptococcus pneumoniae antigens in serum and urine specimens was studied. We tested serum and urine specimens from 44 patients with bacteremic pneumonia (23 S. pneumoniae, 13 H. influenzae type b, 11 other) with commercial latex agglutination kits (Directigen, Bactigen) for S. pneumoniae and H. influenzae type b antigens. All specimen samples were randomized and read blindly by two readers. Interreader reproducibility was 100%. The sensitivity and specificity of both kits for H. influenzae type b antigens in serum and urine were greater than 90%. None of the 24 urine samples from S. pneumoniae bacteremic patients were positive by either kit, although 6 ng of type 3 polysaccharide could be detected in spiked urine. Sensitivity for S. pneumoniae antigens in serum was 27% for Directigen and 38% for Bactigen. Specificity for S. pneumoniae antigens in serum was 95% for Directigen and 74% for Bactigen. The results suggest that the kits are useful in diagnosing H. influenzae type b pneumonia. However, the commercially available S. pneumoniae reagents tested appear to have limited utility for diagnosing S. pneumoniae pneumonia because both kits lack sensitivity and Bactigen lacks specificity, as well.

Acute Disease↗

PubMed1986

Isolation of Listeria monocytogenes from raw milk.

During a recent outbreak of listeriosis, we examined 121 raw milk samples and 14 milk socks (filters). Listeria monocytogenes was recovered from 15 (12%) of 121 milk specimens and 2 (14%) of 14 milk socks. The optimal processing method consisted of cold enriching diluted milk for 1 month with culture to selective broth, followed by plating.

Agar↗

PubMed1985

Staphylococcus aureus isolates from patients with nonmenstrual toxic shock syndrome. Evidence for additional toxins.

Although toxic shock syndrome toxin-1 (TSST-1) has been proposed as the toxin responsible for toxic shock syndrome, its role in this disease has not been proved. To study this question, we examined Staphylococcus aureus strains isolated from normally sterile sites in patients with nonmenstrual toxic shock syndrome for the presence of TSST-1 production. Only 20 (62.5%) of 32 produced TSST-1, compared with 41 (93%) of 44 vaginal isolates from patients with menstrual toxic shock syndrome. Of strains of S aureus from patients with nonmenstrual toxic shock syndrome, TSST-1-negative isolates were more likely to be associated with a fatal outcome and to not be phage group 1 than TSST-1-positive isolates. Seven of the TSST-1-negative strains were evaluated in a rabbit subcutaneous chamber model of toxic shock syndrome. Fifteen (60%) of 25 rabbits developed a toxic shock syndrome-like illness and nine died. Clinical signs and histopathologic findings in the rabbits were similar to those seen in rabbits inoculated with TSST-1-positive S aureus isolates. These results suggest that other, as yet unrecognized, toxins play a role in toxic shock syndrome, and that TSST-1 production may not be essential to the pathogenesis of toxic shock syndrome.

Adolescent↗

PubMed1985

Pasteurized milk as a vehicle of infection in an outbreak of listeriosis.

Between June 30th and August 30th, 1983, 49 patients in Massachusetts acquired listeriosis. Seven cases occurred in fetuses or infants and 42 in immunosuppressed adults; 14 patients (29 per cent) died. Of 40 Listeria monocytogenes isolates available for testing, 32 were serotype 4b. Two case-control studies, one matching for neighborhood of residence and the other for underlying disease, revealed that the illness was strongly associated with drinking a specific brand of pasteurized whole or 2 per cent milk (odds ratio = 9, P less than 0.01 for the neighborhood-matched study; odds ratio = 11.5, P less than 0.001 for the illness-matched study). The association with milk was further substantiated by four additional analyses that suggested the presence of a dose-response effect, demonstrated a protective effect of skim milk, associated cases with the same product in an independent study in another state, and linked a specific phage type with the disease associated with milk. The milk associated with disease came from a group of farms on which listeriosis in dairy cows was known to have occurred at the time of the outbreak. Multiple serotypes of L. monocytogenes were isolated from raw milk obtained from these farms after the outbreak. At the plant where the milk was processed, inspections revealed no evidence of improper pasteurization. These results support the hypothesis that human listeriosis can be a foodborne disease and raise questions about the ability of pasteurization to eradicate a large inoculum of L. monocytogenes from contaminated raw milk.

Adult↗

PubMed1985

Infections with Mycobacterium chelonei in patients receiving dialysis and using processed hemodialyzers.

Between April and November 1982, 27 of 140 patients in a hemodialysis center in Louisiana were infected with rapidly growing mycobacteria; 14 had bacteremia alone, 3 had soft-tissue infections, 1 had an access-graft infection, and 9 had widely disseminated disease. Of 26 identified isolates, 25 were Mycobacterium chelonei ssp. abscessus, and one was an M. chelonei-like organism. One factor common to all patients was exposure to processed hemodialyzers (artificial kidneys). Environmental sampling of the water-treatment system showed widespread contamination with nontuberculous mycobacteria, which were also recovered from the patient's side (blood compartment) of five of 31 hemodialyzers that had been processed and were ready for use. The formaldehyde concentration was less than 2% in two of three such contaminated dialyzers tested. We hypothesize that patients became infected when their blood circulated through processed dialyzers that contained viable rapidly growing mycobacteria. This outbreak demonstrates that hemodialysis patients may be at risk for developing infections with rapidly growing mycobacteria and that such infections may go unrecognized when routine culture methods are used. It also emphasizes the importance of using effective procedures to disinfect dialyzers in hemodialysis centers.

Adult↗

PubMed1985

Risk of group A meningococcal disease: bacterial interference and cross-reactive bacteria among mucosal flora.

During outbreaks of group A meningococcal disease in Seattle, Wash., and Portland, Oreg., we studied the mucosal flora of the affected population and comparison groups to identify possible determinants of susceptibility and resistance to disease. Antimeningococcal immunoglobulin A can block the bactericidal activity of specific antibodies of other classes and has been associated with susceptibility in adults. We used immunoprecipitation and fluorescent-antibody techniques to detect mucosal microorganisms cross-reactive with group A meningococci that might have stimulated such antibodies. Cross-reactive strains of Bacillus pumilus and Streptococcus faecalis were found. Bacterial interference on mucosal surfaces has been shown to reduce susceptibility to other pathogens. With an agar overlay technique, we sought nasopharyngeal microorganisms that inhibited the growth of group A meningococci. Forty-five percent of subjects carried inhibitory strains representing at least nine different species. Inhibitory strains were less common (32%) in residents from "skid row" areas (see D.J. Bogue, Skid Row in American Cities, University of Chicago Press, for a comprehensive definition of these areas) than in a comparison group that did not experience meningococcal disease (61%), suggesting that their presence may be associated with resistance to acquisition of meningococci or to meningococcal disease.

Adult↗

PubMed1984

Production of toxic-shock-associated protein(s) in Staphylococcus aureus strains isolated from 1956 through 1982.

A total of 281 Staphylococcus aureus strains selected from those submitted to the Centers for Disease Control for phage typing between 1956 and 1982 were tested for the production of toxic-shock-associated protein (TSAP) by isoelectric focusing (IEF) and solid-phase radioimmunoassay. The results suggest that the observed temporal trends in the incidence of toxic-shock syndrome were not primarily due to changes in the distribution of TSAP-positive strains of S. aureus. Overall, 39 (14%) were TSAP positive by both methods. The earliest positive strain was an isolate submitted in 1957. TSAP-positive strains were most prevalent in the group of isolates submitted in 1976 for which 29% reacted, but the percent positive subsequently declined for isolates submitted in later years. TSAP production was more frequent among strains of phage types 29, 29/52, and 52 than among other strains. The use of IEF to identify TSAP detected false-positive proteins. Seven strains were positive by IEF and negative by solid-phase radioimmunoassay, whereas only one was positive by solid-phase radioimmunoassay and negative by IEF.

Bacterial Proteins↗

PubMed1984

Trans-isolate medium: a new medium for primary culturing and transport of Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae.

A diphasic medium, Trans-Isolate medium, was developed for the transport of primary cultures of cerebrospinal fluids from patients with bacterial meningitis. It consists of a charcoal-starch agar slant and soybean-casein digest-gelatin broth buffered at pH 7.2 with 0.1 M 3-(N-morpholino)propanesulfonic acid buffer. In the laboratory, this medium supported the growth and survival of stock cultures of Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae for at least 3 months. Under field conditions in Africa, cerebrospinal fluids from patients suspected of having bacterial meningitis were inoculated directly onto plates of chocolate agar medium and into bottles of Trans-Isolate medium. An etiological agent was isolated from 52 spinal fluids by direct plating. After shipment to Atlanta, Ga., 2 to 4 weeks later, the same etiological agents were recovered from 38 bottles of Trans-Isolate medium.

Bacteriological Techniques↗

PubMed1983

A 1957 outbreak of Legionnaires' disease associated with a meat packing plant.

Retrospective study shows that a 1957 outbreak of pneumonia in Austin, Minnesota, was Legionnaires' disease. Between June 7 and August 9, 1957, 78 persons were hospitalized with acute respiratory disease of unknown cause. Most had fever, headache, cough, and pneumonitis; two died. Ages ranged from 14-83 years; half of the patients were aged 55 years or older. Eighty-seven per cent were men. There were no secondary cases. Forty-six (59%) of the 78 patients were employees at a local meat packing plant, in distinction to the area's total working population (32%). Serosurvey of 15 of the 1957 outbreak cases and 30 controls matched for age, sex, and either occupation or residence was carried out in 1979. Antibody titers were determined for Legionella pneumophila serogroups 1-4 by means of indirect immunofluorescence. Twelve (80%) of the 15 cases and 13 (43%) of the 30 controls had antibody titers of 1:64 or greater to one or more of the L. pneumophila serogroups. Significant differences in L. pneumophila antibody titers (prevalence and level) were found between cases and control groups matched for residence (serogroups 1-3) or occupation (serogroups 2 and 3). Only three of 20 Austin residents with pneumonia diagnosed between 1978 and 1980 had L. pneumophila antibody titers of 1:128 or greater (p less than 0.001), in comparison to cases. These serologic data and the 1957 clinical and epidemiologic observations support the contention that this is the earliest documented outbreak of Legionnaires' disease.

Adolescent↗

PubMed1983

Toxic shock syndrome: modification and comparison of methods for detecting marker proteins in Staphylococcus aureus.

Development of a new medium and modification of incubation conditions increased production of toxic shock syndrome marker proteins and enabled detection of small volumes of pyrogenic exotoxin C (PEC) by isoelectric focusing and staphylococcal enterotoxin F (SEF) by a newly developed solid-phase radioimmunoassay. The results were compared with those obtained with previously described methods. The results were identical, and all PEC-positive isolates were SEF positive. In a second study of 262 randomly selected Staphylococcus aureus isolates examined by isoelectric focusing and solid-phase radioimmunoassay but grown in fresh beef heart medium, 47 (17.9%) isolates were PEC and SEF positive; however, 9 (3.4%) were PEC positive and SEF negative, and 3 (1.1%) were SEF positive and PEC negative. When grown in buffered beef heart yeast extract medium, six of the previously PEC-positive and SEF-negative isolates were PEC negative. Autoradiographic analysis of selected isolates demonstrated that PEC- and SEF-positive strains bound SEF antitoxin to the protein at isoelectric point 7.2, suggesting that in staphylococci from patients with toxic shock syndrome, PEC and SEF are the same protein. In screening staphylococci for toxic shock syndrome marker proteins, isoelectric focusing to identify PEC may detect false-positive proteins and may be more susceptible to technical variation than immunological methods to detect SEF.

Bacterial Proteins↗

PubMed1982

Resistance of Mycobacterium chelonei-like organisms to formaldehyde.

Mycobacterium chelonei-like organisms have been isolated from patients in two outbreaks of peritonitis involving chronic peritoneal dialysis machines routinely disinfected with 2 to 3% formaldehyde. Susceptibility studies revealed that water-adapted M. chelonei-like organism strains could survive 2 h of exposure to 10% formaldehyde.

Ascitic Fluid↗

PubMed1982

In-vitro studies of interactions between tampons and Staphylococcus aureus.

In-vitro studies were done to investigate the role of tampons and Staphylococcus aureus in toxic shock syndrome. Tampons did not enhance the growth of S. aureus in nutrient broth or human blood. Intrinsic contamination of tampons with S. aureus was not found among the 504 tampons cultured (95% confidence limits of fraction contaminated; 0 to 0.007). Toxin-producing S. aureus persisted significantly longer on artificially contaminated Rely tampons (Procter & Gamble) than on the other brands tested. The proportion of clinical isolates of S. aureus capable of producing toxin increased from two of 36 in 1960 to eight of 20 in 1979 (p = 0.002, Fisher's exact test). This general increase in the proportion of toxin-producing strains may partially explain the increase in cases of toxic shock syndrome in recent years.

Bacillus↗

PubMed1981

Epidemic Legionnaires' disease. Airborne transmission down a chimney.

Between June 18 and July 9, 1979, Legionnaires' disease (LD) developed in 13 persons who had visited a hotel complex in Wisconsin. All had visited the part of the hotel that contains the restaurants and meeting rooms (building A). Legionnaires' disease occurred in 1% who had been exclusively in the meeting rooms and in 0.1% who had eaten only at the hotel restaurants. Furthermore, 1.5% exposed to meeting room 1 and none of those exposed only to the other meeting rooms had LD. Legionella pneumophila was isolated from water in the cooling tower on top of building A. Located within 5 m downwind of the cooling-tower exhaust, a chimney with an open damper allowed cooling-tower exhaust (as demonstrated by air tracer studies) to enter meeting room 1 via the fireplace. Although cases did not occur after the cooling-tower water was treated by continuous hyperchlorination and the chimney was sealed, a seven-day lag occurred between treatment and elimination of the organism from the tower water.

Aged↗

PubMed1981

Transmission of group B streptococci. Traced by use of multiple epidemiologic markers.

During a three-week period, septicemia caused by group B Streptococcus, serotype III, developed in four infants born at a community hospital. The first infant had early-onset disease; late-onset disease that appeared, from epidemiologic data, to be nosocomial developed in the other three infants. Bacteriophage typing and antimicrobial susceptibility testing confirmed the relatedness of the isolates. A prospective study designed to differentiate between vertical and nosocomial transmission of group B Streptococcus showed that of 82 infants, 21 (26%) were culture-positive during their hospitalization, and nine of these infants (43%) had been culture-negative at birth. Although serotype III strains were recovered from four of nine infants with apparently nosocomial acquisition, none of the isolates displayed an antibiogram or bacteriophage type similar to that of the isolates involved in the recent cluster. Bacteriophage typing and antimicrobial susceptibility testing in addition to the use of serotyping may be helpful in epidemiologic studies of group B Streptococcus.

Bacteriological Techniques↗