Prevalence of blaZ gene types and the cefazolin inoculum effect among methicillin-susceptible Staphylococcus aureus blood isolates and their association with multilocus sequence types and clinical outcome.

Cefazolin treatment failures have been described for bacteraemia caused by methicillin-susceptible Staphylococcus aureus (MSSA) with type A ß-lactamase and inoculum effect (InE). We investigated the prevalence of blaZ (ß-lactamase) gene types and a cefazolin InE among MSSA blood isolates in South Korea and evaluated their association with specific genotypes. The clinical impact of the cefazolin InE was also evaluated. A total of 220 MSSA isolates were collected from a prospective cohort study of S. aureus bacteraemia. A pronounced InE with cefazolin was defined as a ≥4-fold increase in the minimum inhibitory concentration (MIC) between a standard and high inoculum, resulting in a non-susceptible MIC. Sequencing of blaZ and multilocus sequence typing (MLST) were performed. Clinical outcomes were assessed in 77 patients treated with cefazolin. The blaZ gene was detected in 92 % of the 220 MSSA isolates. Type C ß-lactamase was the most common (53 %), followed by type B (20 %) and type A (17 %). Certain genotypes were significantly associated with specific ß-lactamase types (notably, ST30 and type A ß-lactamase). A pronounced cefazolin InE was observed in 13 % of isolates. Most of these (79 %) expressed type A ß-lactamase and ST30 was the predominant (55 %) clone amongst them. Cefazolin treatment failure was not observed in patients infected with strains exhibiting a pronounced InE. These strains had no impact on other clinical outcomes. In conclusion, the prevalence of a pronounced InE with cefazolin could be dependent upon distributions of MSSA genotypes. Cefazolin can likely be used for the treatment of MSSA bacteraemia (except endocarditis), without consideration of an InE.

Clinical significance of Staphylococcus aureus bacteremia in patients with liver cirrhosis.

Patients with liver cirrhosis (LC) have impaired immunity and thus are predisposed to infections. Few studies have attempted to evaluate Staphylococcus aureus bacteremia (SAB) in LC patients. Therefore, this study prospectively evaluated the clinical characteristics and outcomes of 642 episodes of SAB from August 1, 2008 to September 31, 2010. Of 642 patients with SAB, 109 (17.0 %) were classified as LC patients whereas the remaining 533 (83.0 %) were classified as non-LC patients. The 30-day mortality rate of LC patients was significantly higher than that of patients with other diseases (32 % vs. 22 %, respectively; P = 0.047). The 30-day mortality rates of patients with MSSA bacteremia and MRSA bacteremia were not significantly different among LC patients (35.1 % with MSSA vs. 26.9 % with MRSA; P = 0.41). A univariate analysis of the 30-day mortality rate of LC patients with SAB for survivors and non-survivors showed that rapidly fatal or ultimately fatal according to the criteria of McCabe and Jackson (OR 5.0; 95 % CI 1.60-15.65), septic shock at initial presentation (OR 3.5; 95 % CI 1.18-10.39) and Child-Pugh class C (OR 2.8; 95 % CI 1.20-6.59) were associated with increased mortality. In contrast, the removal of the eradicable focus was associated with decreased mortality (OR 0.14; 95 % CI 0.04-0.52). Disease severity and liver dysfunction may be useful for predicting the prognosis of SAB in LC patients.

Tuberculosis mortality by industry in the United States, 1990-1999.

OBJECTIVE: To identify occupations and industries with elevated respiratory tuberculosis (TB) mortality in the United States for the period 1990-1999, we used National Center for Health Statistics multiple-cause-of-death data, restricted to certain states for which information on decedents' usual industry and occupational information was available and limited to US residents aged > or =15 years. DESIGN: A total of 7686 deaths between 1990 and 1999 were attributed to respiratory TB. Proportionate mortality ratios (PMRs), adjusted for age, sex, and race, were calculated from US census occupation and industry classifications. RESULTS: Industries and occupations involving potential contact with infected cases (e.g., health care workers), those with silica exposure and silicosis (e.g., mining and construction), and those associated with low socioeconomic status had significantly elevated TB mortality. CONCLUSIONS: Overall, the pattern of findings echoes that described in various prior reports, which indicates that the potential for exposure and disease development still persists among certain worker groups. The findings should be useful in guiding occupationally targeted TB prevention programs.

Prevalence of cigarette smoking by occupation and industry in the United States.

BACKGROUND: This study was undertaken to estimate the most recent prevalence of cigarette smoking by occupation and industry in the US, using the data from the third National Health and Nutrition Examination Survey (NHANES III), 1988-1994. METHODS: Included in NHANES III are data on the cigarette smoking status, occupation, industry, and other demographic information of US non-institutionalized civilians obtained through household interview surveys. The study population included 20,032 adults aged 17 years and older. To estimate the prevalence of cigarette smoking across occupation and industry groups, we used the Survey Data Analysis (SUDAAN) software. RESULTS: The prevalence of cigarette smoking was highest among material moving occupations, construction laborers, and vehicle mechanics and repairers. The lowest smoking prevalence was found among teachers. Among industry groups, the construction industry had the highest prevalence of cigarette smoking. CONCLUSIONS: These findings provide information useful for targeting education activities focusing on adverse health effects of cigarette smoking and also for indirect adjustments in analysis of morbidity and mortality by occupation. Am. J. Ind. Med. 40:233-239, 2001. Published 2001 Wiley-Liss, Inc.

Recent trends of age-specific pneumoconiosis mortality rates in the United States, 1985-1996: coal workers' pneumoconiosis, asbestosis, and silicosis.

The authors examined the temporal trends of age-specific pneumoconiosis mortality from coal worker's pneumoconiosis (CWP), asbestosis, and silicosis in the United States in 1985-1996. Mortality data were derived from the National Center for Health Statistics multiple causes of death files for the period. Age-specific mortality rates were computed for three age groups (15-44, 45-64, and > or = 65 years) among decedents with mention of CWP, asbestosis, or silicosis. Linear regression analysis was performed to examine the annual changes in age-specific mortality rates, by age group, with each specific condition. The CWP mortality rates declined significantly (p = 0.0001) in the groups 45 years old and older, but not in the age group 15-44. Asbestosis mortality rates declined significantly (p = 0.005) for the age group 45-64, while increasing (p = 0.0001) for those aged 65 years and older. However, in the younger age group 15-44, the rates showed no significant trend. Silicosis mortality rates declined significantly (p = 0.0001) for all groups. The continued occurrence of deaths from CWP, asbestosis, and silicosis among young adults may be the result of high levels of exposure to occupational risks. These results suggest that pneumoconiosis surveillance may help to evaluate the temporal pneumoconiosis mortality patterns in the United States.

Applications of occupational epidemiology.

The development of occupational epidemiology has been steadily accelerating, both with regard to methodology and the number of studies being conducted. This chapter reviews the general applications of occupational epidemiology and illustrates some of the various studies reported in the literature in order to assist in the practical application of the epidemiologic approach.

Respiratory disease risks in the construction industry.

This chapter focuses on the primary identified respiratory hazards in construction, including respiratory tract cancers, pulmonary and pleural fibrosis, airway diseases, inhalation injuries, and respiratory infection. An extensive table identifies the exposure limits specified by NIOSH, OSHA, and ACGIH for more than 30 substances.

Surveillance for occupational asthma--Michigan and New Jersey, 1988-1992.

PROBLEM/CONDITION: A case of occupational asthma is a sentinel health event indicating a need for preventive intervention. REPORTING PERIOD COVERED: 1988-1992. DESCRIPTION OF SYSTEMS: As part of the Sentinel Event Notification System for Occupational Risks (SENSOR) Program, initiated by CDC's National Institute for Occupational Safety and Health in 1987, state-based surveillance and intervention programs for occupational asthma (OA) have been under development in Michigan and New Jersey. The initial 5-year projects in these states have been completed. RESULTS: From 1988 through 1992, the SENSOR programs in these states identified a total of 535 cases of occupational asthma and related conditions. Of these 535 cases, 328 cases met the SENSOR surveillance case definition for OA. In addition, 128 cases were classified as possible OA, 42 as reactive airways dysfunction syndrome, and 37 as occupationally aggravated asthma. In both Michigan and New Jersey, manufacturing was the industrial sector with the largest proportion of cases. In Michigan, > 40% of the case-patients worked in transportation equipment manufacturing. In New Jersey, 15% of case-patients worked in manufacturing of chemicals and allied products. Overall, isocyanates were the most frequently reported asthma-causing agents (19.4% of cases). Follow-up industrial hygiene sampling measured suspect agents at airborne concentrations generally below the permissible exposure limits established by the Occupational Safety and Health Administration. INTERPRETATION: In its first 5 years, the SENSOR system has led to the identification of previously unrecognized causes of occupational asthma. Overall findings indicate the need for more comprehensive control of such well-known occupational allergens as the isocyanates. In addition, SENSOR interventions have prompted improvements in protection for workers. ACTIONS TAKEN: Approaches to state-based surveillance and intervention for OA are being developed through newly funded 5-year SENSOR projects in four states (California, Massachusetts, Michigan, and New Jersey). The goal is to develop a model for effective state-based OA surveillance that can be applied by any state health department.

The effect of pulmonary impairment on all-cause mortality in a national cohort.

The association between pulmonary impairment and all-cause mortality was investigated among white subjects in a follow-up study of a large national cohort. Pulmonary function was measured during the National Health and Nutrition Examination Survey (NHANESI) (1971 to 1975); subsequent mortality information was obtained from the 1987 NHANES I Epidemiologic Follow-up Study (1982 to 1987). Of 4,764 white sample persons, ages 25 to 74 years examined during NHANES I, 658 (13.8 percent) were identified as having pulmonary impairment defined as a FEV1/FVC < or = 69 percent. A total of 743 (15.6 percent) sample persons died during the follow-up period. The association between pulmonary impairment and all-cause mortality was examined for male and female subjects separately using the Cox proportional hazards model controlling for age, smoking, educational level, body mass index, and respiratory diseases. The analysis suggests that reduced FEV1 percent predicted was a significant risk factor for mortality among both sexes, and the FEV1/FVC ratio was significantly associated with all-cause mortality among male subjects only.

Prevalence of chronic obstructive pulmonary disease in blacks.

Chronic obstructive pulmonary disease (COPD) is a significant cause of morbidity and mortality in blacks. The prevalence of COPD among blacks was estimated from the spirometry data obtained from the first National Health and Nutrition Examination Survey (NHANES), 1971-1975. Of 873 subjects, 585 (67%) had acceptable spirometry trials. Chronic obstructive pulmonary disease was defined as a forced expiratory volume in one second (FEV1) less than 65% of the predicted value. The mean FEV1 percentage predicted was 96.7%. The overall prevalence of COPD was 5.4%; 3.7% for males and 6.7% for females. The prevalence was significantly higher with age for both males and females. The multiple logistic regression analyses showed that age and sex were associated with COPD but respiratory symptoms did not attain statistical significance.

Acceptability and reproducibility criteria of the American Thoracic Society as observed in a sample of the general population.

An analysis of spirograms of 6,486 subjects from the general population, ages 8 to 90, was conducted to determine their ability to satisfy the American Thoracic Society's (ATS) acceptability and reproducibility criteria. The results indicate that both older and younger subjects had more difficulty satisfying the ATS acceptability and reproducibility criteria. The difficulty in satisfying the ATS reproducibility criterion, particularly in younger subjects, was in part associated with their smaller heights and lung volumes. A relatively uniform within-subject variability of FVC and FEV1 in terms of the mean differences between the largest and second largest FVC and FEV1, for all heights, was observed. In addition, unlike the ATS reproducibility criterion, when a constant 200-ml reproducibility criterion for FVC and FEV1 was used, there was no longer a significant difference between the number of reproducibility criterion failures for the 14 different height groups used. These results suggest that the ATS reproducibility criterion, based on a percentage of the FVC and FEV1, may inappropriately classify a higher percentage of subjects with smaller heights and lung volumes as having a nonreproducible test. In contrast, subjects with larger heights and lung volumes are much less likely to fail the ATS reproducibility requirement. These results emphasize the importance of following the ATS recommendation of using the reproducibility criterion only as a goal during data collection, not to classify a subject as having an invalid test.

Prevalence of chronic bronchitis among US Hispanics from the Hispanic Health and Nutrition Examination Survey, 1982-84.

In the Hispanic Health and Nutrition Examination Survey (HHANES), Puerto Ricans had a higher age-adjusted prevalence of self-reported chronic bronchitis (2.9 percent, 95% CI = 2.2, 3.6) than Mexican Americans (1.7 percent, 95% CI = 1.3, 2.1) or Cubans (1.7 percent, 95% CI = 0.9, 2.5). The prevalence of chronic bronchitis was at least 2 times higher in smokers as compared to nonsmokers among Puerto Ricans and Cubans, but not for Mexican Americans.

The impact of pulmonary infections on the survival of lung cancer patients.

To determine the impact of pulmonary infections on survival in patients with lung cancer, a retrospective review of the records of 121 such patients treated at Howard University Hospital in Washington, DC, was done. There were 77 men and 44 women; 118 were black. The mean age was 63.5 years. Forty-three patients had squamous cell carcinoma, 31 had adenocarcinoma, 18 had large cell carcinoma, 19 had small cell carcinoma, and ten were unclassified. The stages were as follows: two patients in Stage 0, 15 in Stage I, seven in Stage II, 45 in Stage III, and 44 in Stage IV. Eight patients could not be staged at diagnosis. Eighty-five patients (70%) had documented infections; 37 had single episodes; and 48 had more than one. The five most common organisms recovered were alpha/gamma streptococci, Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter aerogenes, and Pseudomonas aeruginosa. The median survival of all infected patients was 4.2 months which was significantly shorter than that of uninfected patients who had a median survival of 12.9 months (P less than 0.05). When Stage III patients were analyzed separately, infected patients lived a median of 5.8 months and uninfected patients, 13.4 months (P less than 0.05). This study indicated that pulmonary infections frequently occur in patients with lung cancer and suggested that they may adversely affect survival.

Comprehensive family practice clerkship in a minority institution.

A comprehensive family practice clerkship program at Howard University College of Medicine has been conducted since 1970. This institution is one of three predominantly black institutions offering a family practice program. The senior clerkship is mandatory and at least 20 to 25 percent of each class elect to participate in a four-to six- week family practice preceptorship. As a result of the clerkship's success, over 50 percent of the program's graduates actively practice in primary medical manpower shortage or medically underserved areas.

Skin cancer in blacks in the United States.

Skin cancer is rare in blacks compared with whites in the United States. The most common form is squamous-cell carcinoma, not basal-cell carcinoma, as it is in whites. Sunlight does not appear to be an important etiologic factor in skin cancer in blacks, as most lesions occur on covered areas. Malignant melanoma is low in frequency but commonly affects acral areas and has a poor prognosis. Mycosis fungoides and dermatofibrosarcoma protuberans appear to have a high frequency among skin cancers. Squamous-cell carcinoma, malignant melanoma, and mycosis fungoides have a relatively high mortality rate in blacks. Bowen's disease and Kaposi's sarcoma occur in blacks but are rare. As there is a high frequency of squamous-cell carcinoma of the skin in blacks, prevention and early detection should benefit the patient. Considering the difficulties encountered in applying epidemiologic methods to skin cancer on a national scale, etiologic studies should be conducted in carefully selected areas. Future investigations of skin cancer in blacks should include an examination of risk factors such as burns, trauma, and diet and familial and immunologic aspects as well.

Current epidemiologic status on aging in U.S. blacks: update on hypertension and diabetes.

The total number of American blacks aged 65 years and over is estimated to be approximately 2.3 million, and the black elderly population will continue to increase faster than the white elderly population throughout the remainder of this century. During the period 1985 to 2025, the elderly population in the United States will increase to 105 percent.The prevalence of hypertension and diabetes for the elderly population (65 years and over) is much higher in blacks than in whites. During the period 1976 to 1980, 76.5 percent of black women aged 65 to 74 years had definite hypertension, compared with 53.4 percent of white women.Many factors are associated with the development of hypertension and diabetes in blacks. Specfic epidemiologic studies are necessary to identify black-white differences in risk factors, including biomedical risk, socioeconomic status, psychosocial risk, nutritional status, lifestyle, and genetic factors.

Evaluation of recent trends in cancer mortality and incidence among blacks.

Recent trends in the cancer incidence, mortality, and 5-year survival rate for the black population were evaluated using the available national data up to 1981. Blacks have the highest overall age-adjusted cancer rates in both incidence and mortality of any US population group. The overall cancer incidence rates for blacks rose 17%, while for whites it increased 13% from 1969 to 1981. The rate in black men has increased 22.9%, while the rate in black women has increased 13.1%. The overall increase is the result of increases in cancers of the lung, prostate, colon-rectum, and esophagus. The age-specific incidence of lung cancer reflects the decrease of its incidence in those between 20 and 40 years of age because of the change in smoking habits after the Surgeon General's report on smoking. The overall cancer mortality rates for blacks increased 39% during the period. Lung cancer had the highest mortality rate, having increased more than 77.8% since 1969. This trend greatly reflects the recent increase in lung cancer incidence among black women. The overall 5-year cancer survival pattern for blacks was almost unchanged from 1973 to 1981, while whites had slightly higher survival rates during this period. However, blacks had substantial increases in survival rates for cancers of the esophagus and bladder during the period.

Increased cancer risks in blacks: a look at the factors.

Incidence and mortality rates of cancer in blacks have been increasing at a faster rate than in whites. In particular, recent incidence rates of lung cancer in black men have increased, while the rates in white men decreased for the first time since 1982 to 1983. This leveling off in incidence for whites may suggest the beginning of a downturn in lung cancer because the smoking prevalence has decreased substantially since 1965.There is considerable evidence that cancer risks in blacks are higher than in whites. The major risk factors to cancer include cigarette smoking, diet, alcohol, and occupational exposure to industrial carcinogens. Other factors, including immunogenetic and unknown risks, might be associated partially with an increased incidence of cancer in blacks. Analytic epidemiologic studies addressing the relationship between genetic factors, or biomarkers, and cancer along with epidemiologic methods are warranted. Key factors that contribute to the prevention of cancer mortality should be identified and promulgated through primary or secondary cancer prevention programs.

Age and prevalence of sickle-cell trait in a large ambulatory population.

We performed hemoglobin electrophoresis in 30,400 apparently healthy black individuals in the Washington D.C. Metropolitan area, who were participating in a community based sickle-cell screening program during the period 1978-1985. The overall prevalence of sickle-cell trait was 6.7%. The frequency of sickle-cell trait in various age groups, which included young children, adults, and individuals over 65 years of age, ranged from 6.4 to 7.4%. There were no statistically significant differences in the prevalence of sickle-cell trait among the various age groups, nor did we detect a significant trend for increasing or decreasing sickle cell frequency with advancing age (P = 0.418). Thus, in this population sickle-cell trait appears to have no effect on longevity. If the various complications of sickle-cell trait reported in the literature are not fortuitous, their frequency and/or severity must be too low to affect prevalence figures.