The relationship between age and fever magnitude

BACKGROUND

Infections are an important cause of morbidity and mortality in older people; however, they are often difficult to diagnose because the signs and symptoms of infection in older people are frequently atypical. Fever, one of the most important signs of infection, is a case in point. Preliminary evidence suggests that the febrile response in older persons is blunted, leading to the clinical maxim, "the older, the colder." The objective of this study was to assess the effect of age on the febrile response to moderate-to-severe pneumonia in hospitalized patients adjusted for the effect of anatomic site at which the temperature was measured.

METHODS

This is a retrospective cohort study of 320 hospitalized patients with moderate-to-severe pneumonia. The study was designed to assess the effect of age on the febrile response to moderate-to-severe pneumonia in hospitalized patients, adjusting for the effect of the anatomic location of the temperature measurement. The highest temperature of each day and the anatomic sites at which temperatures were taken (axillary, oral, rectal, or other) on days 1 and 2 of infection and at hospital discharge. Baseline demographic information, including age, were obtained for each patient.

RESULTS

There were 320 patients (median age, 64 years; range, 18-97 years). Using a linear regression model, significant inverse correlations were found between age and the temperature for patients on the first and second days of hospitalization (P < 0.001). For each decade increase in age, the average temperature on the first 3 days of infection was lower by 0.15 degrees C. Temperature at discharge, a surrogate for baseline temperature, also decreased at an equal rate with age.

CONCLUSION

In this study, the febrile response to infections was reduced with increasing age and baseline temperatures were generally lower in older patients.

MRSA colonization and the risk of MRSA bacteraemia in hospitalized patients with chronic ulcers

A cohort study of patients with chronic ulcers was performed to estimate the risk of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia in a population colonized with MRSA. During a five-year period (January 1990-May 1995), 911 patients with chronic ulcers (CU), as determined by ICD9-CM code search, were admitted to an acute care hospital. Sixty percent (545/911) of these patients with CU had their CU cultured to detect MRSA and 30% (166/545) of these were colonized with MRSA. Among patients with surveillance cultures, those with MRSA colonization had significantly more days of hospitalization and were also more likely to have a central venous catheter during hospitalization compared with patients without MRSA colonization. MRSA bacteraemia occurred in 4% (36/911) of CU patients during the study period and in 6% (32/545) of cultured CU patients. Among the 545 patients who had surveillance cultures, the risk ratio for MRSA bacteraemia when there was MRSA colonization of their chronic ulcer was 16 (95% CI 6-45). Among patients with MRSA colonization, central venous catheter use was the only significant risk factor for MRSA bacteraemia. In 16 of the 28 patients with MRSA bacteraemia and MRSA colonization, the MRSA colonization was identified more than seven days before the bacteraemia. This cohort study identifies MRSA colonized CU patients in an acute care setting as a high-risk population for MRSA bacteraemia.

A survey on handwashing practices and opinions of healthcare workers

Studies have consistently demonstrated rates of handwashing compliance are less than 50%. The objective of this study was to gain the following information about handwashing: self-reported compliance; attitudes towards handwashing in different patient settings; and attitudes towards interventions aimed at increasing compliance. A 74-question survey was administered to healthcare workers in two tertiary care hospitals. One hundred and ninety nine healthcare workers completed the survey and 89% reported that handwashing is an important means of preventing infection. Sixty-four percent believed that they washed their hands as often as their peers and 2% believed that they washed less often than their peers. Patients with diarrhoea, AIDS or patients on antibiotics led to increased handwashing. Relative to potential interventions, 76% reported that rewards for handwashing would have no effect, 73% reported that punishment would have no effect and 80% reported that easy access to sinks and availability of washing facilities would lead to increased compliance. This survey suggests that healthcare workers understand the importance of handwashing, but tend to overestimate their own compliance. Healthcare workers are not in favour of interventions involving rewards and punishments, but are more attracted to interventions that make handwashing easier.

Predicting methicillin resistance and the effect of inadequate empiric therapy on survival in patients with Staphylococcus aureus bacteremia

BACKGROUND

The restriction of vancomycin hydrochloride use is recommended as a measure to decrease the emergence of vancomycin resistance in gram-positive organisms; however, vancomycin also is the treatment of choice for methicillin-resistant Staphylococcus aureus (MRSA) infections. If vancomycin use is restricted to patients with documented infections due to methicillin-resistant organisms, then patients with MRSA infections may not initially receive vancomycin. This study was performed to determine factors that predict MRSA bacteremia and if ineffective empiric antibiotic therapy increased the risk of death in patients with S aureus bacteremia.

METHODS

We conducted a retrospective cohort study of all patients with clinically significant S aureus bacteremia (132 episodes in 128 patients) diagnosed between October 1, 1995, and January 1, 1998, at an urban acute care Veterans Affairs medical center (approximately 200 acute care beds) in Baltimore, Md. During the study period, vancomycin was a restricted antibiotic. Empiric use had to be approved by an attending physician specializing in infectious diseases.

RESULTS

Compared with patients who had methicillin-sensitive S aureus bacteremia, patients with MRSA bacteremia were significantly older (70 vs 58 years; P<.01), more likely to have a history of MRSA (47% vs 6%; P<.01) and a nosocomial infection (76% vs 50%; P<.01), and less likely to use injection drugs (8% vs 32%; P<.01). In addition, compared with patients who had methicillin-sensitive S aureus bacteremia, patients with MRSA bacteremia were significantly less likely (45% vs 98%; P<.01) to receive effective antibiotic therapy during the first 48 hours of hospitalization. However, the risk of death due to ineffective empiric therapy was less than 1 (relative risk, 0.82; 95% confidence interval, 0.36-1.88) and did not change significantly when adjusted for age, occurrence of sepsis, or nosocomial infection.

CONCLUSIONS

The results of this study support the safety of the restriction of vancomycin use in patients with clinically significant S aureus bacteremia. However, patients with a history of MRSA are more likely to have future MRSA infections and should receive empiric therapy using vancomycin for possible S aureus infections, particularly for nosocomial infections.

Improved tuberculosis infection control practices in Maryland acute care hospitals

BACKGROUND

In 1992 and 1993, the Maryland Hospital Association and the Maryland Department of Health and Mental Hygiene conducted 2 surveys of tuberculosis prevention practices in Maryland hospitals that showed poor compliance with the 1990 Centers for Disease Control and Prevention's guidelines for preventing transmission of tuberculosis in health care facilities.

OBJECTIVE

The objective of this study was to assess compliance in 1997 with the Centers for Disease Control and Prevention's guidelines in Maryland acute care hospitals.

METHODS

A written questionnaire with 3 components-Infection Control, Employee Health, and Microbiology Laboratory-was mailed to 56 Maryland acute care hospitals.

RESULTS

Seventy-three percent of the surveys were returned. One hundred percent of responding hospitals with tuberculosis isolation rooms reported negative pressure ventilation, 6 air exchanges per hour, and air exhausted to the outside or through high-efficiency particulate air filters. One hundred percent of the responding hospitals reported providing National Institute for Occupational Safety and Health-approved respiratory protection for health care workers; this compared with 24% in 1992 (P <.01). One hundred percent of the responding hospitals reported performing at least annual tuberculin skin testing; this compared with 50% in 1992 (P <. 01).

CONCLUSIONS

The survey results demonstrate excellent compliance with the 1994 Centers for Disease Control and Prevention recommendations for tuberculosis control in Maryland acute care hospitals, even in those facilities determined to be at minimal to low risk for tuberculosis exposure. The proposed Occupational Safety and Health Administration regulations are unlikely to further reduce the risk of tuberculosis exposure to health care workers in Maryland acute care hospitals.

Adherence to asthma guidelines in general practices

Adherence to asthma practice guidelines is low. Improved compliance could potentially improve care of patients with asthma. The purpose of this study was to determine if patients managed in a general practice with an associated asthma clinic are more likely to use asthma medications according to clinical practice guidelines than patients managed in the general surgery of the practice. A cross-sectional study of adult asthmatics, aged 18-55 years, was conducted in six British general practices. Prescription data on all asthma medication was collected for a 6-month period. Information on asthma clinic attendance, age, sex, employment status, other medical illness, and how patients used their inhaled beta2-agonist was collected through questionnaire. The prescription data for asthma medication and patient use of inhaled beta2-agonist were compared to the British Thoracic Society's (BTS) Guidelines for Management of Asthma in Adults to determine if the patient's asthma medication regimen was appropriate. There was no significant association found between appropriate asthma medication and asthma clinic attendance or other patient characteristics. Adherence to the BTS guidelines was low. Fifty-eight percent of the asthma patients used asthma medication regimens that were not consistent with the BTS guidelines published 1 year earlier. Adherence to the BTS guidelines was low regardless of patient characteristics, including asthma clinic attendance, age, sex, employment status, other medical illness, or individual practice. These findings underscore the need to document the utility of clinical practice guidelines which may improve physician compliance.

A randomized trial of surgical antimicrobial prophylaxis with and without vancomycin in organ transplant patients

BACKGROUND

Gram-positive organisms, including vancomycin-resistant enterococci (VRE), have emerged as major pathogens on the organ transplant service at our institution. We hypothesized that our use of vancomycin as part of routine surgical prophylaxis increased the risk of VRE colonization and infection; conversely, there was concern that failure to use vancomycin prophylaxis would increase peri-operative morbidity due to gram-positive organisms.

METHODS

Renal transplant recipients (n = 88) were randomized to receive either a) vancomycin/ceftriaxone or b) cefazolin; and pancreas transplants (n = 24) to receive either a) vancomycin/gentamicin or b) cefazolin/gentamicin. Stool samples or rectal swabs were obtained for culture for enterococci within 24 h of transplantation and weekly while hospitalized.

RESULTS

Enterococci were isolated on stool culture from 38 (34%) of 102 patients at the time of transplantation; 4 (11%) of the isolates were VRE. The percentage of patients who subsequently acquired VRE was low (1-7% per wk) but remained constant during hospitalization. There was no association between new VRE detection and vancomycin use for either prophylactic or therapeutic purposes. Forty-four patients (39%) had a post-operative infection with 46% of these infections due to gram-positive organisms; rates were unaffected by prophylactic vancomycin use. Pancreas transplant patients who did not receive vancomycin prophylaxis had a significantly longer initial hospitalization (p = 0.03); however, differences were not statistically significant when total length of stay (LOS) within the first 90 d of transplantation was compared.

CONCLUSIONS

Vancomycin surgical prophylaxis does not appear to have an effect on VRE colonization or infection, or on rates of infection with gram-positive bacteria. Elimination of vancomycin prophylaxis in renal transplant patients may be a reasonable part of an overall program to limit vancomycin usage, although as a single measure, its impact may be minimal. Vancomycin surgical prophylaxis may be of greater importance in pancreas transplants.

Decreased seroprevalence for Toxoplasma gondii in Seventh Day Adventists in Maryland

Despite its widespread prevalence, uncertainties remain about the relative contribution of various routes of transmission to the overall rate of infection with Toxoplasma gondii, particularly in developed countries. To explore the hypothesis that meat consumption is an important risk factor for infection, a cross-sectional seroprevalence study was performed on healthy adults in one region in the state of Maryland. The population included Seventh Day Adventists who as a group follow a diet containing no meat, and control community volunteers who were not Seventh Day Adventists. Thirty-one percent of the population had serologic evidence of T. gondii infection. People with T. gondii infection were older (49 versus 42 years old; P < 0.01, by t-test) and less likely to be Seventh Day Adventists (24% versus 50%; P < 0.01, by chi-square test) than people without T. gondii infection. When adjustments were made for age and gender through multiple logistic regression, Seventh Day Adventists had a significantly decreased risk of T. gondii infection (odds ratio = 0.21, 95% confidence interval = 0.09-0.46, P = 0.0001) compared with the controls. While the basis for this effect remains to be determined, one possible protective factor is the general adherence of Seventh Day Adventists to a diet that does not contain meat.

Vancomycin use in a hospital with vancomycin restriction

We evaluated vancomycin use in a hospital with endemic vancomycin-resistant enterococci and a vancomycin restriction program. Only 68% of vancomycin was prescribed appropriately. Inappropriate use was due primarily to empirical therapy. In the patients with a microbiological diagnosis following empirical therapy, 83% (25/30) had infections due to bacteria sensitive to an appropriate antibiotic other than vancomycin. However, only 60% (15/25) of these patients had their vancomycin orders changed.

Colonization with vancomycin-resistant enterococci in chronic hemodialysis patients

Vancomycin-resistant enterococcus (VRE) has been identified with increased frequency in dialysis populations, but the risk factors for VRE colonization are not well defined in hemodialysis patients. Patients from a university-affiliated outpatient dialysis center had surveillance stool or rectal cultures for VRE during April 1994 and January 1996. The combined cohort of 168 patients was followed-up for all-cause mortality, subsequent hospitalization, and VRE infection. Demographic and risk factor information, including age, gender, race, diabetes, coronary artery disease (CAD), and human immunodeficiency virus (HIV) infection, were collected on all patients. Sixteen patients had surveillance cultures grow vancomycin-resistant Enterococcus faecium or E faecalis (VREF), and nine additional patients had clinical cultures positive for VREF. The median follow-up time for patients with positive surveillance or clinical cultures for VREF was 421 days versus 423 days for those without VREF. Patients with positive surveillance cultures for VREF had less time on hemodialysis before screening (median = 207 days v 822 days; P < 0.01), and more hospitalization in the year before screening (median = 19 days v 3 days, P < 0.01) compared with those without VREF. Patients with VREF colonization were more likely to develop infection with VREF (25% v 1%, P < 0.01) than those without VREF colonization. However, adjusting for age, diabetes, coronary artery disease, and acquired immune deficiency syndrome (AIDS) using Cox-proportional hazards models, the presence of VREF on screening culture was not associated with increased risk of death (RR = 1.1, P = 0.86). Thus after adjusting for other comorbidities, VREF colonization was not associated with increased mortality. Patients with end-stage renal disease (ESRD) on hemodialysis who are hospitalized are more likely to have VREF, but longer duration on hemodialysis was not associated with presence of this organism. This suggests that VRE transmission occurs predominantly in the inpatient setting.

Clostridium difficile infection is a risk factor for bacteremia due to vancomycin-resistant enterococci (VRE) in VRE-colonized patients with acute leukemia

A cohort study was conducted in a cancer center to identify risk factors for bacteremia with vancomycin-resistant enterococci (VRE) in neutropenic cancer patients colonized with VRE. There were 10 patients with VRE bacteremia among 56 colonized with VRE, of whose charts 51 were available for review. One hundred percent of patients with VRE bacteremia (10 of 10) vs. 56% of patients without VRE bacteremia (23 of 41) had acute leukemia (P = .01, Fisher's exact test). Four of the 10 patients with VRE bacteremia had a positive Clostridium difficile toxin assay within 6 days of their first positive VRE blood culture. Both C. difficile infection and antimicrobial (vancomycin and ciprofloxacin) use during VRE colonization were significant risk factors for VRE bacteremia in univariate analysis. When a Cox proportional hazards model was used to account for differences in follow-up time, C. difficile infection was the only statistically significant risk factor (risk ratio, 8.2; P = .007) for VRE bacteremia in VRE-colonized patients with acute leukemia.

Ty1 transposition in Saccharomyces cerevisiae is nonrandom

A large collection of Ty1 insertions in the URA3 and LYS2 loci was generated using a GAL1-Ty1 fusion to augment the transposition frequency. The sites of insertion of most of these Ty elements were sequenced. There appears to be a gradient of frequency of insertion from the 5' end (highest frequency) to the 3' end (lowest frequency) of both loci. In addition we observed hotspots for transposition. Twelve of the 82 Ty1 insertions in the URA3 locus were inserted in exactly the same site. Hotspots were also observed in the LYS2 locus. All hotspots were in the transcribed part of the genes. Alignment of the sites of insertion and of the neighboring sequences only reveals very weak sequence similarities.

Effects of estradiol and tamoxifen on creatine kinase in rodent mammary carcinomas

The effects of altered estrogenic environments on creatine kinase (CK) and adenylate kinase (AK) were studied in two rodent mammary tumor systems, R3230AC and primary 7,12-dimethylbenz(a)anthracene (DMBA)-induced carcinomas, to determine whether response of these enzymes could be related to their hormone dependence. The hormonal perturbations studied were ovariectomy and administration of various doses of estradiol valerate or the antiestrogen tamoxifen. Total CK activity and AK activity were assessed by a spectrophotometric assay followed by electrophoretic separation of the CK isozymes to determine their relative activities. In the ovarian-independent R3230AC tumors, estrogen treatment produced a dose-related decrease in CK activity, whereas CK was not responsive in ovarian-dependent DMBA-induced tumors. Adenylate kinase activity remained unchanged regardless of the hormonal perturbation. Glucose-6-phosphate dehydrogenase and lactate dehydrogenase, which were studied for comparative purposes, were both estrogen responsive. While both estrogenic and antiestrogenic effects on enzyme activities were observed in the DMBA-induced tumors, the effect of tamoxifen in the R3230AC tumors was generally estrogenic. We conclude that the effect of estrogen on CK-BB in DMBA-induced tumors is not sufficient to be used as a biochemical marker of hormone dependence.

Comparison of latex agglutination and counterimmunoelectrophoresis for the detection of pneumococcal antigen in elderly pneumonia patients

A Streptococcus pneumoniae latex agglutination (LA) test (Bactigen; Wampole Laboratories, Div. Carter-Wallace, Inc., Cranbury, N.J.) and counterimmunoelectrophoresis (CIE) were compared for the detection of pneumococcal antigen in serum and urine specimens from 68 elderly patients with pneumococcal pneumonia. The cases were categorized according to the presumptive role of S. pneumoniae: definite, putative, questionable (poor score), or questionable (mixed flora). Serum and urine samples were collected on days 1 to 3, 4 to 6, and 7 to 9 of illness and screened in parallel by LA and CIE. LA detected pneumococcal antigen in the serum or urine or both from 31 (46%) of the 68 pneumococcal pneumonia cases compared with 10 (15%) of cases detected by CIE. The highest rates of detection were noted in the 17 definite (bacteremic) cases: 88% by LA and 38% by CIE. The detection rates for both tests were lower in the other nonbacteremic pneumonia categories. Pneumococcal antigen was detected more often in urine specimens than in serum specimens by LA and CIE and was detected in the urine of 92 and 46% of definite cases, respectively, after 7 to 9 days of illness despite antibiotic therapy. Both tests were specific when tested with nonpneumococcal pneumonia cases, but LA detected pneumococcal antigen in two of seven chronic bronchitis cases. This study suggests that LA is as specific and more sensitive than CIE and is useful for detecting antigen in the elderly with proven bacteremic pneumococcal pneumonia. LA is less sensitive for detecting nonbacteremic pneumococcal pneumonia and, therefore, would be of limited value in the care and study of the institutionalized elderly.