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Biomedical subjects

J A Elliott

Publications and source records attributed to J A Elliott.

At least 37 records · Page 2Linked to original sources
PubMed1998

Sudden increase in isolation of group B streptococci, serotype V, is not due to emergence of a new pulsed-field gel electrophoresis type.

Until recently, group B streptococcus, serotype V (GBS-V), was an infrequent cause of disease. It is now recognized as a significant cause of infections in both children and adults. To determine if this increase was due to the recent introduction and spread of a single clone of GBS-V, we analyzed, by pulsed-field gel electrophoresis (PFGE), the SmaI chromosomal DNA digests of 45 bacteria: 41 isolated from human infections between 1986 and 1996 in the United States, 2 from human infections in Argentina, and 2 from naturally infected mice. Seventeen patterns were found and arbitrarily designated patterns A to Q. Pattern N constituted 24 (53%) of the isolates and was found in all of the years tested and from all surveillance areas, as well as in both isolates from Argentina, and was very similar to the GBS-V isolated from a mouse. Pattern P was found in three isolates, pattern F was found in two, and the remaining patterns were found in one isolate each. We concluded that the majority of isolates of GBS-V are of one PFGE subtype and that this subtype was predominate before the increase in disease caused by GBS-V and that GBS-V disease is caused by several different subtypes.

Adult↗
PubMed1997

Blunted phase-shift responses to morning bright light in premenstrual dysphoric disorder.

Patients with premenstrual dysphoric disorder (PMDD) respond therapeutically to sleep deprivation and light therapy. They have blunted circadian rhythms of melatonin. The authors sought to test the hypothesis that these disturbances are a reflection of a disturbance in the underlying circadian pacemaker or, alternatively, that they reflect a disturbance in the input pathways to the clock. To test these hypotheses, after a 2-month diagnostic evaluation, 8 patients who met DSM-IV criteria for PMDD and 5 normal control (NC) subjects underwent two studies to determine whether PMDD subjects showed (1) altered melatonin sensitivity to light suppression (Study 1) and (2) altered phase-shift responses to morning light as a measure of the functional capacity of the underlying pacemaker (Study 2). In both studies, measurements were made during asymptomatic follicular and symptomatic luteal menstrual cycle phases in PMDD patients. The results of Study 1 showed no significant effect of group or menstrual cycle phase on the amount or percentage of suppression of melatonin by light. The results of Study 2 showed that with respect to the variable of offset time, PMDD subjects, when symptomatic, showed a reduced and directionally altered melatonin phase-shift response to a morning bright light stimulus; in 4 of 5 NC subjects, melatonin offset was advanced by bright morning light, whereas in PMDD subjects, it was delayed (3 subjects) or not shifted (5 subjects) (group effect, p = .045). Study 2 also revealed that area under the curve also changed differentially in PMDD versus NC subjects. In summary, the primary findings from this pilot study suggest that in PMDD there is a maladaptive (directionally altered and blunted) response to light in the symptomatic luteal phase. Because the suppressive effects of light were similar in PMDD and NC subjects, the previously observed low melatonin levels in this disorder do not likely represent a disturbance in pineal reactivity to suprachiasmatic nucleus efferents. Instead, the findings support a possible disturbance in PMDD in the clock itself or its coupling mechanisms.

Adult↗
PubMed1996

Risk factors for carriage of drug-resistant Streptococcus pneumoniae among children in Memphis, Tennessee.

OBJECTIVES: To determine risk factors for carriage of drug-resistant Streptococcus pneumoniae to understand better the factors promoting spread of these isolates. STUDY DESIGN: We obtained medical and demographic information and nasopharyngeal swab specimens from 216 children less than 6 years old with upper respiratory tract infections, seeking medical care at five Memphis, Tenn, study sites. We evaluated risk factors for carriage of penicillin-nonsusceptible S. pneumoniae (NSSP) among 100 children with S. pneumoniae isolates. Patterns of antimicrobial prescription were recorded for enrolled children. RESULTS: Independent risk factors for carriage of NSSP included an increased number of antimicrobial treatment courses during the previous 3 months and white race. Day care attendance approached statistical significance (p = 0.07). Most children with upper respiratory tract infection received a prescription for antimicrobial drugs. These prescriptions were more common for white children than for black children. CONCLUSIONS: Increased use of antimicrobial drugs enhances the risk of carriage of NSSP. This may contribute to the higher risk among white children of NSSP infection; however, after control for antimicrobial use, white children were still at an increased risk of infection with NSSP, possibly through greater exposure to resistant strains.

Anti-Bacterial Agents↗
PubMed1996

The continued emergence of drug-resistant Streptococcus pneumoniae in the United States: an update from the Centers for Disease Control and Prevention's Pneumococcal Sentinel Surveillance System.

As part of ongoing national surveillance, serotyping and antimicrobial susceptibility testing were done on all pneumococcal isolates recovered from normally sterile body sites of patients at 12 hospitals in 11 states during 1993-1994. Of 740 isolates, 14.1% were penicillin-nonsusceptible Streptococcus pneumoniae (PNSP; MIC > or = 0.1 microgram/mL), 3.2% were penicillin-resistant (MIC > or = 2.0 micrograms/mL), and 25.5% were nonsusceptible to more than one antimicrobial agent. PNSP were more prevalent among children < 6 years old (18.4%) than patients > or = 18 years old (11.7%) and among white persons (16.2%) than black persons (12.1%). PNSP represented 15 serotypes, but 89% of PNSP were serotypes in the 23-valent pneumococcal vaccine. The proportion of isolates with reduced susceptibility and the number of serotypes of nonsusceptible strains are increasing in the United States. Improved local surveillance for PNSP infections, judicious use of antibiotics, and development and use of effective pneumococcal vaccines will be required to treat and prevent disease caused by these strains.

Adolescent↗
PubMed1996

Risk factors for nasopharyngeal carriage of resistant Streptococcus pneumoniae and detection of a multiply resistant clone among children living in the Yukon-Kuskokwim Delta region of Alaska.

BACKGROUND: Children < 2 years old living in the Yukon-Kuskokwim Delta (YKD) region of Alaska have one of the highest pneumococcal bacteremia rates of in the world. METHODS: To determine the prevalence of and risk factors for infection with intermediate or resistant Streptococcus pneumoniae in the YKD, we cultured nasopharyngeal secretions of healthy children < or = 5 years old, reviewed their hospital records and administered questionnaires to accompanying parents. RESULTS: Of 185 children evaluated we obtained 95 pneumococcal isolates; drug susceptibility patterns and serotyping results were available for 92. Of these, 33 (36%) were intermediate or resistant to at least one drug class tested; 27 isolates were intermediate (minimum inhibitory concentration 0.1 to 1.0 mg/l) and none were resistant to penicillin. Compared with other isolates, capsular serotype 6B isolates were more likely to be intermediate or resistant to at least one drug (relative risk, 5.3; P < 0.001) and to more than one drug (relative risk, 17.0; P < 0.001). The majority of 6B isolates had identical pneumococcal surface protein A patterns. Carriage of intermediate or resistant pneumococcus was associated with age < 2 years (relative risk, 3.0; P < 0.001) but not with antibiotic use or other evaluated risk factors. CONCLUSIONS: Young age but not antibiotic use was associated with carriage of intermediate or resistant S. pneumoniae in the YKD region of Alaska. Much of the intermediate or resistant pneumococcus in the YKD may have resulted from the proliferation of a single capsular serotype 6B clone.

Alaska↗
PubMed1996

Sex differences in alcohol preference and drinking patterns emerge during the early postpubertal period.

Young male and female Sprague-Dawley rats (30 days old) were assigned randomly to three treatment groups: (1) alcohol treatment--received beer with 5% ethanol added, food, and water ad libitum; (2) pair-fed treatment--received nonalcoholic beer plus sucrose and food to match intake by the alcohol-treated animals; and (3) control treatment--received food and water ad libitum. Animals were tested for alcohol preference for 24 hr and then received their assigned treatments for a period of 30 days, followed by a period of abstinence before alcohol preference testing again at 74 days of age. Males given free access to beer and water did not drink large quantities of beer. Females given free access to beer and water drank a lot of beer on the first day, but decreased intake until approximately 52 days of age. A developmental change in young female rats at approximately 52 days of age resulted in increased voluntary ethanol intake, possibly caused by hormonal changes associated with the establishment of estrous cycles. When the animals were tested for alcohol preference at 74 days of age after a period of abstinence, males and females in the pair-fed group had greater alcohol preference than animals in the other groups. Females in the pair-fed group had greater alcohol intake based on body weight than males in the pair-fed group and males and females in all other groups. These results provide insight into sex differences in the development of voluntary drinking behavior and responses of drinking behavior to the early stress of pair-feeding.

Age Factors↗
PubMed1996

Antimicrobial susceptibilities of Lactococcus lactis and Lactococcus garvieae and a proposed method to discriminate between them.

The MICs of antimicrobial agents contained in the SCEPTOR Streptococcus MIC panels (Becton Dickinson Microbiology Systems) were determined for Lactococcus lactis, L. garvieae, and unknown Lactococcus species. Several isolates had reduced susceptibilities to many of the antimicrobial agents contained in the panel. For L. garvieae, the MICs of penicillin and, possibly, cephalothin were higher than for L. lactis, and unlike L. lactis, L. garvieae was resistant to clindamycin, indicating that knowledge of the Lactococcus species causing an infection might influence the choice of antimicrobial therapy. Susceptibility to clindamycin can also be used to differentiate between L. lactis and L. garvieae.

Bacteriological Techniques↗
PubMed1995

Relapsing invasive group B streptococcal infection in adults.

OBJECTIVE: To study recurrent group B streptococcal infection in adults. DESIGN: Patients with more than one reported group B streptococcal infection were identified through active surveillance for this infection. Sterile-site group B streptococcal isolates were evaluated for serotype and molecular subtyping using restriction endonuclease analysis of chromosomal DNA (REAC). SETTING: All acute-care hospitals in Maryland. PATIENTS: Nonpregnant residents of Maryland 18 years of age or older. RESULTS: 22 adults had at least two group B streptococcal episodes that were separated by 2 to 95 weeks (mean, 24 weeks). Of 395 patients with invasive group B streptococcal infection who survived the first episode and were followed for at least 1 year, 17 (4.3% [95% CI, 2.6% to 6.9%]) had more than one episode. Several patients were found to have endocarditis or osteomyelitis during the second episode. Group B streptococcal isolates from both episodes were obtained from 18 of 22 patients. Of the 18 isolate pairs, 13 (72% [CI, 46% to 90%]) had identical REAC patterns; the probability that at least 13 matches would be found by chance alone was less than 0.000001. Among patients with recurrent infection caused by the same strain, the interval between episodes was shorter (mean, 14 weeks) than that among patients with recurrent infection caused by another strain (mean, 43 weeks; P = 0.05). CONCLUSIONS: Recurrent group B streptococcal infection is common among adults and in most cases appears to be caused by relapse. The optimal management of adults with a first episode of group B streptococcal infection needs to be further defined to minimize the likelihood of recurrent disease.

Adolescent↗
PubMed1995

The prevalence of drug-resistant Streptococcus pneumoniae in Atlanta.

BACKGROUND: Streptococcus pneumoniae is a major cause of illness, and the emergence of drug-resistant strains threatens to complicate the management of pneumococcal infections. We conducted a laboratory-based surveillance for drug-resistant S. pneumoniae among patients with invasive pneumococcal infections in Atlanta. METHODS: From January through October 1994, pneumococcal isolates from 431 patients with invasive disease in metropolitan Atlanta were serotyped and tested to determine their susceptibility to various antimicrobial agents. Susceptibility to the antimicrobial agents was defined according to guidelines established by the National Committee for Clinical Laboratory Standards. RESULTS: The annual incidence of invasive pneumococcal infection was 30 cases per 100,000 population. Isolates from 25 percent of the patients were resistant to penicillin (7 percent were highly resistant), and isolates from 26 percent were resistant to trimethoprim-sulfamethoxazole (7 percent highly resistant). Fifteen percent of the isolates were resistant to erythromycin, 9 percent to cefotaxime (4 percent were highly resistant), and 25 percent to multiple drugs. Drug-resistant pneumococci were found in both children and adults. Children under six years of age were more likely than older children and adults to have isolates resistant to multiple drugs or cefotaxime. Whites were more likely than blacks to have invasive pneumococcal infections caused by drug-resistant organisms. Among white children younger than six years, 41 percent of the S. pneumoniae isolates were resistant to penicillin. CONCLUSIONS: Drug-resistant strains of S. pneumoniae are common among both children and adults in Atlanta. Although blacks had a higher incidence of invasive pneumococcal infections than whites, whites were more likely to be infected with a drug-resistant isolate. Control of drug-resistant pneumococci will require more judicious use of antimicrobial agents and wider use of the pneumococcal polysaccharide vaccine.

Adolescent↗
PubMed1995

High prevalence of multidrug-resistant Streptococcus pneumoniae among children in a rural Kentucky community.

In 1992 drug-resistant Streptococcus pneumoniae was cultured with increasing frequency from aspirates of middle ear fluid from children with acute otitis media in a rural Kentucky community. To determine the prevalence of carriage of drug-resistant S. pneumoniae in the community, we obtained nasopharyngeal swabs from 158 (70%) of 227 children attending a child daycare center and from 82 children attending the county health center. S. pneumoniae was isolated from 126 children. Among 123 isolates tested 65 (53%) were penicillin-resistant, including 41 (33%) strains that were highly resistant; 61 (50%) were multidrug-resistant. Serotypes 19F, 6B, 23F and 6A comprised 89% of the penicillin-resistant isolates. Detection of a variety of serotypes and drug resistance patterns among nasopharyngeal isolates of S. pneumoniae suggests that multidrug-resistant pneumococcal strains are endemic in this community. Surveillance for drug-resistant pneumococci with the use of respiratory secretions obtained by nasopharyngeal swab may provide useful information on the prevalence of drug-resistant strains causing invasive disease and otitis media. Such information could be used to guide empiric therapy of pneumococcal infections.

Carrier State↗
PubMed1995

Identification, classification, and clinical relevance of catalase-negative, gram-positive cocci, excluding the streptococci and enterococci.

Several new genera and species of gram-positive, catalase-negative cocci that can cause infections in humans have been described. Although these bacteria were isolated in the clinical laboratory, they were considered nonpathogenic culture contaminants and were not thought to be the cause of any diseases. Isolation of pure cultures of these bacteria from normally sterile sites has led to the conclusion that these bacteria can be an infrequent cause of infection. This review describes the new bacteria and the procedures useful for clinical laboratories to aid in their identification. The clinical relevance and our experience with the various genera and species are reviewed and discussed.

Animals↗
PubMed1994

An epidemic of pneumococcal disease in an overcrowded, inadequately ventilated jail.

BACKGROUND: In the United States many correctional facilities now operate at far over capacity, with the potential for living conditions that permit outbreaks of respiratory infections. We investigated an outbreak that was identified in an overcrowded Houston jail after two inmates died of pneumococcal sepsis on the same day. Outbreaks of pneumococcal disease have been rare in the era of antibiotics. METHODS: We assessed risk factors for pneumococcal disease in both a case-control and a cohort study. Ventilation was evaluated by measuring carbon dioxide levels and air flow to the living areas of the jail. The extent of asymptomatic infection was determined by culturing pharyngeal specimens from a random sample of inmates. Type-specific immunity was determined with an enzyme immunoassay. RESULTS: Over a four-week period, 46 inmates had either acute pneumonia or invasive pneumococcal disease due to Streptococcus pneumoniae serotype 12F. The jail's capacity had been set at 3500 inmates, but it housed 6700 at the time of the outbreak; the inmates had a median living area of only 34 ft2 (3.2 m2) (interquartile range, 28 to 56 ft2 [2.6 to 5.2 m2]) per person. There were significantly fewer cases of disease among inmates with 80 ft2 (7.4 m2) per person or more (P = 0.030). Carbon dioxide levels ranged from 1100 to 2500 ppm (acceptable, < 1000), and the ventilation system delivered a median of only 6.1 ft3 of outside air per minute per person (interquartile range, 4.4 to 8.5 ft3; recommended, > or = 20 ft3). The attack rate was highest among inmates in cells with the highest carbon dioxide levels and the lowest volume of outside air delivered by the ventilation system (relative risk, 1.94; 95 percent confidence interval, 1.08 to 3.48). Of underlying medical conditions, intravenous drug use was most strongly associated with disease (odds ratio, 4.50). The epidemic strain (serotype 12F) was cultured from 7 percent of the asymptomatic inmates. Of 11 case patients tested with the enzyme immunoassay, 9 (82 percent) lacked preexisting immunity to this strain. CONCLUSIONS: Severe overcrowding, inadequate ventilation, and altered host susceptibility all contributed to this outbreak of pneumococcal disease in a large urban jail.

Adult↗
PubMed1994

Emergence of drug-resistant pneumococcal infections in the United States.

OBJECTIVE: To estimate drug susceptibility patterns of Streptococcus pneumoniae in selected hospitals in the United States and to characterize the epidemiology of invasive drug-resistant pneumococcal infections. DESIGN: Minimum inhibitory concentrations (MICs) for a variety of commonly used antimicrobial drugs were determined for pneumococcal isolates submitted to the Centers for Disease Control and Prevention (CDC). Risk factors for drug-resistant pneumococcal infection were evaluated. SETTING: Hospital laboratories in the United States submitting pneumococcal isolates to the CDC between October 1, 1991, and September 30, 1992. PARTICIPANTS: A total of 544 persons with pneumococci isolated from normally sterile sites. RESULTS: A total of 13 hospitals in 12 states actively participated in an ongoing pneumococcal surveillance study. Resistance to penicillin was detected in 6.6% of isolates, including 1.3% of isolates with MICs of 2.0 micrograms/mL or more (compared with < 0.02% of isolates with MIC > or = 2.0 micrograms/mL identified by CDC surveillance from 1979 to 1987). A total of 16.4% were resistant to at least one of the following drugs or drug classes: penicillin, cephalosporins, macrolides, combination trimethoprim and sulfamethoxazole, and chloramphenicol. Six serotypes (6B, 23F, 14, 9V, 19A, and 19F) accounted for nearly 85% of strains resistant to at least one drug class. Children were more likely than adults to be infected with strains resistant to trimethoprim-sulfamethoxazole, erythromycin, or chloramphenicol. CONCLUSIONS: Emergence of drug-resistant pneumococcal infections will present critical challenges to clinicians for treating patients with pneumococcal disease. Widened and intensified surveillance is needed. These data suggest that current recommendations for use of 23-valent pneumococcal capsular polysaccharide vaccines should be aggressively promoted and that development and evaluation of new conjugate pneumococcal vaccines may be a crucial part of strategies for prevention.

Anti-Bacterial Agents↗
PubMed1994

Complex circadian regulation of pineal melatonin and wheel-running in Syrian hamsters.

Circadian regulation of pineal melatonin content was studied in Syrian hamsters (Mesocricetus auratus), especially melatonin peak width and the temporal correlation to wheel-running activity. Melatonin was measured by radioimmunoassay in glands removed at different circadian times with respect to activity onset (= CT 12). Pineal melatonin peak width (h; for mean > or = 125 pg/gland) and activity duration (alpha) were both 4-5 h longer after 12 or 27 weeks than after 5 or 6 days in continuous darkness (DD). Increased peak width was associated with a delay in the morning decline (M) of melatonin to baseline, correlated with a similar delay in wheel-running offset. In contrast, the evening rise (E) in melatonin occurred at approximately the same circadian phase regardless of the length of DD. Fifteen min light pulses produced similar phase-shifts in melatonin and activity. In a phase advance shift, M advanced at once, while E advanced only after several days of adjustment. Independent timing of shifts in the E and M components of the melatonin rhythm suggest that these events are controlled separately by at least two circadian oscillators whose mutual phase relationship determines melatonin peak width. This two-oscillator control of melatonin peak width is integral to the circadian mechanism of hamster photoperiodic time measurement.

Animals↗
PubMed1994

Postarteriographic femoral pseudoaneurysms: treatment with ultrasound-guided compression.

Pseudoaneurysms following femoral arterial catheterization are increasingly common and are related to factors such as catheter size, periprocedural anticoagulation, hypertension, and improper technique. Ultrasound-guided compression as a noninvasive technique for repair of these lesions was prospectively evaluated in 16 patients whose mean age was 61 years. Nine patients were on anticoagulants and six had hypertension. All patients presented with an enlarging groin hematoma, a pulsatile mass, and/or a bruit following femoral catheterization. Seventeen femoral artery pseudoaneurysms, including one with an associated arteriovenous fistula, were detected using color-flow Doppler imaging. Three pseudoaneurysms thrombosed spontaneously. The remaining 14 were managed with compressive therapy lasting from 20 to 100 minutes. No complications were encountered during the compressions and 10 false aneurysms (71%) responded completely (mean time to thrombosis of 38 minutes). Two lesions responded partially to compression and there were two failures, the latter associated with excessive anticoagulation in one patient and a well-established pseudoaneurysm in the second patient. Only one pseudoaneurysm (6%) in the series required surgical correction. Ultrasound-guided compression of acute pseudoaneurysms in the groin is a safe, inexpensive, and effective method of treatment.

Adult↗
PubMed1993

Outbreak of pyogenic abscesses after diphtheria and tetanus toxoids and pertussis vaccination.

Nine children who received diphtheria and tetanus toxoids and pertussis vaccine from the same vial at a clinic in Colorado developed pyogenic abscesses at the site of injection. Eight abscesses required surgical drainage and five children were hospitalized. Group A Streptococcus (GAS) was cultured from eight wounds and Staphylococcus aureus was also isolated from four. Epidemiologic investigation revealed that within the hour of the first child's vaccination, three children had been diagnosed in the clinic with GAS pharyngitis. GAS recovered from repeat throat swabs from two of these children and the eight case-isolates were all serotype M-12, T-12 and had identical immunoblot patterns on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Laboratory simulation studies demonstrated that GAS can survive for at least 4 days on the external surface of a vaccine vial rubber stopper and contaminate needles inserted through the stopper. Swabbing the stopper with 70% isopropyl alcohol resulted in effective disinfection. To prevent potential contamination meticulous attention to sterile technique is important when withdrawing vaccine from multidose vaccine vials.

1-Propanol↗