Imaging protein statistical substate occupancy in a spectrum-function phase space.

Hemeprotein ligand rebinding studies reveal varying IR absorbance and rebinding functions across a cryogenic ensemble. Since IR-active vibrations and rebinding barriers couple to structural coordinates, spectral and functional heterogeneity arise from conformational heterogeneity. Modeling rebinding data as a spectrally resolved superposition of first-order rate processes and employing maximum entropy regularization, protein heterogeneity is imaged as an ensemble occupancy of a spectrum-function phase space. Results from myoglobin rebinding carbon monoxide are discussed.

Nationwide outbreak of listeriosis due to contaminated meat.

We used molecular subtyping to investigate an outbreak of listeriosis involving residents of 24 US states. We defined a case as infection with Listeria monocytogenes serotype 4b yielding one of several closely related patterns when subtyped by pulsed-field gel electrophoresis. Patients infected with strains yielding different patterns were used as controls. A total of 108 cases were identified with 14 associated deaths and four miscarriages or stillbirths. A case-control study implicated meat frankfurters as the likely source of infection (OR 17.3, 95% CI 2.4-160). The outbreak ended abruptly following a manufacturer-issued recall, and the outbreak strain was later detected in low levels in the recalled product. A second strain was recovered at higher levels but was not associated with human illness. Our findings suggest that L. monocytogenes strains vary widely in virulence and confirm that large outbreaks can occur even when only low levels of contamination are detected in sampled food. Standardized molecular subtyping and coordinated, multi-jurisdiction investigations can greatly facilitate detection and control of listeriosis outbreaks.

An outbreak of Yersinia enterocolitica O:8 infections associated with pasteurized milk.

In October 1995, an outbreak of Yersinia enterocolitica O:8 infections occurred in the Upper Valley of Vermont and New Hampshire. Ten patients were identified, median age 9 years (range, 6 months-44 years). Three patients were hospitalized; 1 underwent an appendectomy. Consumption of bottled pasteurized milk from a local dairy was associated with illness (matched odds ratio undefined; lower 95% confidence interval, 1.9). No deficiencies in pasteurization procedures or equipment were detected. Y. enterocolitica O:8 was isolated from 1 raw-milk sample and from a fecal sample from 1 dairy pig. The route of contamination was not determined; this outbreak likely resulted from postpasteurization contamination of milk. Dairy pigs were the most likely source of contamination. Milk bottles were likely contaminated by rinsing with untreated well water prior to filling or by other environmental routes. Educating dairy owners about Y. enterocolitica and postpasteurization contamination is necessary to prevent further outbreaks.

Geographic variation in allergic fungal rhinosinusitis.

Allergic fungal rhinosinusitis (AFRS) has a worldwide distribution. This survey of 20 otolaryngologic practices throughout the United States confirmed a variation in the frequency of AFRS relative to endoscopic sinus procedures performed for all other diagnoses. The highest incidence occurred in Memphis, Tennessee at 23%, with three other southern practices reporting a frequency of at least 10%. In the northern locations the frequency ranged from 0 to 4%. No correlation with mould counts was demonstrated, possibly because of incomplete mould data relative to most of the surgical locations.

Cardiovascular disease risk factors are lower in African-American vegans compared to lacto-ovo-vegetarians.

OBJECTIVE: This study was undertaken to determine if African-American strict vegetarians (vegans) exhibit lower blood pressure (BP) and a more favorable serum lipid profile than their lacto-ovo vegetarian (LOV) counterparts, and if plasma ascorbic acid (AA) concentrations could explain any group differences in these cardiovascular disease (CVD) risk factors. METHODS: Habitual dietary intake, anthropometric characteristics, blood pressure, and blood lipids and ascorbic acid concentrations were determined in African-American study participants (male vegans, n = 14, age = 45.6 years; male LOV, n = 49, age = 49.8; female vegans, n = 31, age = 51.1, female LOV, n = 94, age = 52.1) recruited from Seventh-Day Adventist Churches in several cities in the northeastern United States. RESULTS: Body mass index (BMI) was significantly lower in the vegans (24.7 +/- 1.9 kg/m2) compared to LOV (26.4 +/- 0.45 kg/m2). There were no diet or gender differences in BP. Serum total cholesterol (3.75 +/- 0.12 vs. 4.51 +/- 0.10 mmol/L), LDL-cholesterol (2.06 +/- 0.13 vs. 2.65 +/- 0.09 mmol/l), and triglycerides (0.94 +/- 0.07 vs. 1.17 +/- 0.04 mmol/L) were significantly (p < 0.05) lower in vegans compared to LOV, but there were no dietary group differences in HDL-C. The ratio of total to HDL-cholesterol was significantly lower in vegans than in LOV (3.0 +/- 0.13 vs. 3.7 +/- 0.13). There were no dietary group differences in plasma AA concentrations. However, in the entire sample, plasma AA was inversely associated with BP (SBP: r = -0.46, p < 0.001, DBP: r = -0.32, p < 0.001), but unrelated to the serum lipid concentrations. CONCLUSION: African-American vegans exhibit a more favorable serum lipid profile than lacto-ovo-vegatarians and plasma AA is inversely related to BP in African-American vegetarians but does not explain any of the differences in CVD risk factors between vegans and lacto-ovo vegetarians.

An outbreak of salmonellosis among children attending a reptile exhibit at a zoo.

OBJECTIVE: In January 1996, an outbreak of diarrhea caused by Salmonella Enteritidis occurred in children attending a Komodo dragon exhibit at a metropolitan zoo. We sought to determine the extent of the outbreak and mode of transmission. STUDY DESIGN: A case-control study was conducted. Controls were randomly selected from zoo membership lists and matched to patients by age group and date of exhibit visit. RESULTS: Of 65 patients identified, 39 had confirmed and 26 had suspected cases. The median age was 7 years (range, 3 months to 48 years); 55% were enrolled in the case-control study. No patients and two (4%) controls reported touching a dragon; however, 83% of patients but only 52% of controls touched the wooden barrier that surrounded the dragon pen (odds ratio = 4.0, 95% CI 1.2 to 13.9). Washing hands at the zoo after visiting the dragons was highly protective (OR = 0.14, 95% CI 0.03 to 0.7). Cultures from the patients, one dragon, and the exhibit barriers yielded Salmonella Enteritidis, phage type 8. On the basis of an attack rate of 4.3% among exhibit attendees under 13 years old on whom data were collected, we estimate that 315 additional cases of salmonellosis occurred among visitors in this age group. CONCLUSION: This large outbreak demonstrates the importance of environmental contamination in the transmission of Salmonella from reptiles, and the protective value of hand washing. Recommendations regarding reptile exhibits and reptilian pets should emphasize this indirect route.

Emergence of multidrug-resistant Salmonella enterica serotype typhimurium DT104 infections in the United States.

BACKGROUND: Strains of salmonella that are resistant to antimicrobial agents have become a worldwide health problem. A distinct strain of Salmonella enterica serotype typhimurium, known as definitive type 104 (DT104), is resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline and has become a major cause of illness in humans and animals in Europe, especially the United Kingdom. METHODS: To characterize typhimurium DT104 infections in the United States, we analyzed data collected by local and state health departments and public health laboratories between 1979 and 1996 in national surveys of the antimicrobial-drug resistance of salmonella. Selected typhimurium isolates with the five-drug pattern of resistance were phage typed. RESULTS: The prevalence of typhimurium isolates with the five-drug pattern of resistance increased from 0.6 percent in 1979-1980 to 34 percent in 1996. In 1994-1995, such isolates were identified in samples from 36 of the 46 surveillance sites (78 percent). Thirty-nine of 43 typhimurium isolates with the five-drug pattern of resistance identified in 1994-1995 and 1996 were phage type DT104 or a closely related phage type. CONCLUSIONS: Multidrug-resistant typhimurium DT104 has become a widespread pathogen in the United States. More prudent use of antimicrobial agents in farm animals and more effective disease prevention on farms are necessary to reduce the dissemination of multidrug-resistant typhimurium DT104 and to slow the emergence of resistance to additional agents in this and other strains of salmonella.

Molecular subtyping of Neisseria meningitidis serogroup B: comparison of five methods.

In order to compare methods for subtyping Neisseria meningitidis serogroup B isolates, 96 isolates obtained from various locations in the United States and northwestern Europe were subtyped by five methods: monoclonal antibody (MAb)-based serotyping and serosubtyping, DNA macrorestriction analysis by pulsed-field gel electrophoresis (PFGE), multilocus enzyme electrophoresis (MEE), ribotyping, and PCR-restriction fragment length polymorphism of the internally transcribed spacer region of the rRNA operon (ITS PCR-RFLP). All N. meningitidis serogroup B isolates were typeable by PFGE, MEE, ribotyping, and ITS PCR-RFLP. Only 44.8% of the isolates were completely typeable (both serotype and serosubtype determination) by MAb-based serotyping and serosubtyping. 60.4% of the isolates could be serotyped but not serosubtyped, and 90.6% of the isolates could be either serotyped or serosubtyped. Simpson's discrimination indices of diversity for the methods were as follows: PFGE, 99.7%; MEE, 99.4%; ribotyping, 98.8%; MAb serotyping, 75.8%; MAb serotyping and/or serosubtyping 97.5%; and ITS PCR-RFLP, 84.2%. The high degree of diversity observed by PFGE, MEE, and ribotyping can be explained by the fact that isolates were collected from different geographic locations at various times. PFGE, MEE, and ribotyping showed greater discriminatory abilities than MAb-based serotyping and serosubtyping or ITS PCR-RFLP.

Decline in meningococcal antibody levels in African children 5 years after vaccination and the lack of an effect of booster immunization.

Antibodies to group A meningococcal polysaccharide were measured by hemagglutination (HA) and by ELISA in sera obtained from Gambian children before vaccination and 3 weeks, 2 years, and 5 years after vaccination with a group A + group C meningococcal capsular polysaccharide vaccine. Children were 1-4 years old at the time of vaccination. Most showed a good initial response to vaccination, including those aged 1-2 years. However, antibody titers declined progressively during follow-up, and 5 years after vaccination, antibody titers measured by both HA and ELISA had returned to prevaccination levels. This decline was not influenced significantly by a booster dose of vaccine given 2 years after initial immunization. Administration of malaria chemoprophylaxis reduced the rate at which antibody levels fell after initial immunization. Sustained protection of children against group A meningococcal disease will require the development of vaccines that are immunogenic in infants and that can induce T cell memory.

Epidemic meningococcal disease in Nairobi, Kenya, 1989. The Kenya/Centers for Disease Control (CDC) Meningitis Study Group.

An epidemic of meningococcal disease occurred in Nairobi, Kenya, during 1989, outside the "meningitis belt" of sub-Saharan Africa. About 3800 cases occurred between April and November (250/100,000 population). The case-fatality rate was 9.4% among hospitalized patients. Areas that included Nairobi's largest slums had particularly high attack rates. The epidemic displayed an unusual age distribution, with high attack rates among those 20-29 years old. A vaccination campaign was conducted. By early January, the weekly case count had fallen to 25 from a high of 272 (in September). A case-control study estimated the vaccine efficacy to be 87% (95% confidence interval, 67%-95%). A model estimated that the vaccination campaign reduced the number of cases by at least 20%. Multilocus enzyme electrophoretic typing demonstrated that the strain responsible for this large epidemic is closely related to strains that caused other recent epidemics, documenting further spread of what may be a particularly virulent clonal complex of group A Neisseria meningitidis.

Immunoaffinity purification, stabilization and comparative characterization of listeriolysin O from Listeria monocytogenes serotypes 1/2a and 4b.

We developed a simple and highly effective procedure for stabilizing the haemolytic activity of listeriolysin O (LLO) from Listeria monocytogenes after immunoaffinity purification. The haemolytic activity of LLO was stabilized by eluting it directly into tubes containing an alkaline buffer (5 mM lysine, 140 mM KCl, 50% ethylene glycol, pH 11.5). The purified LLO retained 100% of its haemolytic activity after 6 weeks of storage at -20 degrees C. LLO purified from a strain of L. monocytogenes serotype 1/2a (ATCC 43249) and LLO purified from a strain of L. monocytogenes serotype 4b (F 2365) isolated from a Mexican-style cheese, showed no significant differences in pH and temperature stability. When incubated in buffers at pH values from 4 to 12 at 4 degrees C and 25 degrees C, LLO from serotypes 1/2a and 4b retained maximal haemolytic activity at pH 8 after 4 h of incubation. LLO from both serotypes lost their haemolytic activity after incubation at 50 degrees C for 25 min.

Multicenter comparison of levels of antibody to the Neisseria meningitidis group A capsular polysaccharide measured by using an enzyme-linked immunosorbent assay.

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.

Respiratory viruses and mycoplasma as cofactors for epidemic group A meningococcal meningitis.

To investigate the role of coincident respiratory viral and mycoplasmal agents in the pathogenesis of meningococcal meningitis, we performed a matched case-control study of 62 patients with group A meningococcal meningitis during an epidemic in Chad. Case patients were more likely than controls to have nasal colonization or infection with respiratory viruses and Mycoplasma species (matched odds ratio, 23; 95% confidence interval, 3.1 to 170). Respiratory pathogens were found more commonly in older patients with meningitis (odds ratios were 2.9 for children under age 5 years and 46.5 in those over age 15 years), consistent with the increasing risk of meningitis with age during epidemics. In controls, the presence of respiratory pathogens increased the risk of upper-respiratory-tract symptoms but did not significantly increase meningococcal carriage.

Panel of reference strains for evaluating serologic reagents used to identify gonococci.

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.

Haemophilus ducreyi infection in south Florida: a rare disease on the rise?

Increased numbers of patients with genital ulcers sought medical attention in the Palm Beach County, Florida, Sexually Transmitted Disease clinics from Aug 1, 1982 to Aug 31, 1983. We established that a small proportion of subsequent cases of genital ulcers were caused by Haemophilus ducreyi, the etiologic agent associated with chancroid. We also set up a surveillance system to monitor this sexually transmitted infection, and have illuminated several recent cases of chancroid occurring in that area. This outbreak of chancroid suggest that clinicians practicing in south Florida consider chancroid (generally a rare disease in the United States) in their differential diagnoses of genital ulcers.

Chromosomally mediated resistance in Neisseria gonorrhoeae in the United States: results of surveillance and reporting, 1983-1984.

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.

Correlation of auxotype and protein I type with expression of disease due to Neisseria gonorrhoeae.

To explore the correlation of outer membrane protein I (PI) type and auxotype to clinical expression of infection with Neisseria gonorrhoeae, we characterized nutritional requirements by auxotyping and PI serovars by coagglutination assay with monoclonal antibodies of 325 consecutive clinical isolates of N. gonorrhoeae. The clinical status of each infected individual was determined by chart review. The predominant auxotype required proline, citrulline, and uracil with or without hypoxanthine (Pro-Cit-Ura-[Hyx-]) and accounted for 22% of all gonococcal strains. Pro-Cit-Ura-(Hyx-) strains were recovered from seven of 15 men with asymptomatic urethral infections (P less than .01). Of the 325 strains, 33% were PIA and 67% were PIB serovars. All five isolates in disseminated gonococcal infection were PIA serovars (P less than .01). Three percent of 168 urethral infections in men were complicated by epididymitis, and 17% of 135 cervical infections in women were complicated by pelvic inflammatory disease (P less than .0005). Neither of these complications was associated with a particular auxotype or PI serovar.