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Biomedical subjects

A M Yinnon

Publications and source records attributed to A M Yinnon.

At least 19 recordsLinked to original sources
PubMed2003

Use of time-trend analysis in the design of empirical antimicrobial treatment of urinary tract infection.

Selection of empirical treatment of hospitalized patients with urinary tract infection (UTI) is usually based on the results of urine culture as obtained from the local microbiology laboratory. In order to improve the precision and reliability of traditional methods, we analyzed temporal changes in the results of urine culture and antibiograms and stratified the results by inpatient department and the presence/absence of an indwelling catheter. The database consisted of urine cultures obtained during the first 3 months of each year over a 10-year period between 1991 and 2000. Only urine samples that grew a single organism at a concentration of >10(5) cfu were included in the analysis. Trend statistical tools, readily available but thus far not used for microbiological analyses, were applied to assess the decay in activity of individual antibiotic agents over time and to calculate susceptibility rates of organisms in subsets of urine samples. Organisms, antimicrobial susceptibility rates and the degree of decay in antimicrobial susceptibility rates varied significantly according to the location of the patient in the hospital and the presence of an indwelling catheter. Stratified trend analysis is a useful tool that can be helpful in designing and adapting clinical guidelines for the selection of appropriate empirical antibiotic treatment for the individual patient with urinary tract infection.

Anti-Bacterial Agents↗
PubMed2002

Changing epidemiology of infective endocarditis: a retrospective survey of 108 cases, 1990-1999.

The aim of this study was to report the experience with infective endocarditis over the past decade, describe the changing clinical and epidemiological features of the disease, and attempt to determine the optimal number of blood culture sets required for diagnosis. All cases diagnosed during a 10-year period were reviewed clinically and microbiologically. In addition, a retrospective assessment of blood culture data was performed. From the period 1990-1999, 108 cases that met the von Reyn or Duke's criteria were recorded. The major underlying cardiac condition was the presence of a prosthetic valve ( n=33 patients, 31%). Among patients with native valves, nonrheumatic valvular heart disease of the elderly was the most common underlying factor ( n=19 patients, 25%). Overall, 13 patients (11%) died. Predictors on admission for increased mortality were shortness of breath, age >60 years, time to defervescence, erythrocyturia, hemoglobin level <10 g/dl, and leukocytosis >15,000 (all P<0.05). Analysis of blood culture data showed that the diagnostic yield among groups from whom either only one or more than six blood culture sets were drawn was reduced compared with that among groups from whom between two and five culture sets had been taken. The outcome of endocarditis in this series from a community hospital was much more favorable compared with that reported in surveys from large tertiary centers. Moreover, obtaining more than two or three blood cultures is neither helpful nor cost-effective in the initial assessment of patients with suspected endocarditis.

Aged↗
PubMed2002

Risk factors for nephrotoxicity in elderly patients receiving once-daily aminoglycosides.

BACKGROUND: There remain concerns about the safety of once-daily dosing of aminoglycosides (AGs) in the elderly. AIM: To assess the safety of once-daily AGs in elderly patients and evaluate possible risk factors for nephrotoxicity. DESIGN: Prospective, non-interventional surveillance study. METHODS: All patients receiving AGs were monitored over 4 months. Clinicians determined the AG dose for each patient after estimating patient weight and calculating creatinine clearance (CrCl) using the Cockcroft-Gault formula. Parallel figures were calculated by the investigators using measured weight. Clinicians obtained an AG trough level 24 h after initiation of treatment, and, if non-toxic, every 5-7 days thereafter. AG toxicity was defined as an increase in serum creatinine of > or =50%. RESULTS: In the study period, 249 consecutive patients received an AG: 116 (47%) males, mean+/-SD age 75+/-16 years. Forty-two (17%) received amikacin and 207 (83%) gentamicin. An increase of > or =50% in serum creatinine was detected in 31/249 (12.4%); maximal creatinine was < or =177 micromol/l in 16/249 (6.4%), 186-265 micromol/l in nine (3.6%), and >265 micromol/l in six (2.4%). None developed oliguric renal failure. Renal damage correlated with a high AG trough level (>1.1 microg/ml) (p<0.001); haemoglobin level <10 g/dl (p<0.05); hospital admission >7 days prior to AG treatment (p<0.005); and AG treatment > or =11 days (p<0.05). Mean CrCl based on estimated weight was 52+/-18 ml/min; that based on actual weight was 71+/-37 ml/min. Despite this, mean AG dose was 1.3+/-0.6 higher than optimal. CONCLUSIONS: Oliguric and/or lasting renal toxicity is rare in elderly patients receiving once-daily aminoglycosides for <11 days, if regular trough drug levels are monitored.

Adult↗
PubMed2001

Whither infectious diseases consultations? Analysis of 14,005 consultations from a 5-year period.

During a 5-year period, data from all infectious disease (ID) consultations were recorded in a computerized database, which included 9068 new and 4937 additional consultations. The purpose of these 14,005 consultations was therapy (for 58%), diagnosis (for 13%), both (for 24%), and prophylaxis (for 4%); 51% were performed at the bedside, and the remainder were by discussion (19%) or telephone (30%). Recommendations included the following: initiation, change, or discontinuation of antibiotics (in 46%); performance of diagnostic tests (in 20%) or surgical procedures (in 1%); prophylaxis (in 3%); or no change (in 29%). Analysis of new versus additional consultations revealed significant differences. A new ID consultation was given at a rate of 6.0 consultations per 100 hospitalized patients; the rate per department correlated with the expenditure on antimicrobials per patient admission. During the study period, expenditure on antimicrobials per admission steadily decreased, from $44 in 1995 to $30 in 1999, a 35% reduction. In conclusion, analysis of data from ID consultations enables the ID service to evaluate its activity and to direct efforts to departments with high rates of nosocomial infections, antimicrobial resistance, and/or antimicrobial use.

Anti-Infective Agents↗
PubMed2001

Adult patients with occult bacteremia discharged from the emergency department: epidemiological and clinical characteristics.

To determine the epidemiological and clinical characteristics of patients who were discharged from the emergency department (ED) and subsequently proved to have bacteremia, we prospectively assessed all patients examined in the ED during an 18-month period from whose blood cultures a significant organism was isolated. Discharged patients were contacted and reevaluated. Two case-control studies were conducted, in which each study patient was matched with a total of 4 control patients. During the study period, 46,336 patients were examined in the ED; 78% were adults and 22% were children. Blood cultures were performed for 25% of the adult patients and for 44% of the children. Although the occurrence of occult bacteremia in patients who were discharged from the ED is 3.7 times more common in children than in adults, the absolute numbers of discharged adults and children with occult bacteremia are similar. Careful clinical assessment will not prevent discharge of some of these patients; however, these patients in general do well and can be safely recalled for reevaluation and complementation of therapy.

Adolescent↗
PubMed2001

Longitudinal surveillance of antibiotic use in the hospital.

We evaluated antimicrobial use in our hospital by department, including indications for use, source of infections, use of the microbiology laboratory, and appropriateness of prescribing, in a prospective, comparative, non-interventional study of all patients receiving antimicrobial agents. We excluded departments where antimicrobial use was negligible. The other 19 departments were followed for 3 (n=4) or 4 (n=15) months, including 2 consecutive months in the spring-summer and either 1 or 2 in the autumn-winter. Antimicrobial therapy was followed from initiation, through possible adaptations, and possible change from intravenous to oral therapy, until discontinuation of treatment. Overall, 6376 antibiotics were given to 2306 patients. Of the surveyed hospitalized patients, 62%+/-22% received antibiotics, with a range of 4-100% per department. Antibiotics were prescribed for infections acquired in the community (3037 instances, 47%), in the hospital (2182, 34%), in a nursing home (575, 9%), and for prophylaxis continued post-operatively (582, 9%). The most common indications for antimicrobial use were: respiratory tract infection (1729, 27%), urinary tract infection (955, 15%), sepsis (701, 11%), intra-abdominal infections (663, 10%), prophylaxis 582 (9%), soft-tissue infection (572, 9%), and surgical site infection (319, 5%). Univariate indicators for appropriateness of treatment were: age, department, site of infection, source of infection, antimicrobial drug and serum creatinine (all p<0.001). Forty-nine antimicrobials were prescribed in 279 combinations, 58% as single agent and 42% as drug combinations. Half of all antimicrobial use consisted of four agents: cefuroxime (19.1%), metronidazole (11.3%), gentamicin (10.6%) and ampicillin (10.2%), which together accounted for 20% of expenditure on antibiotics. Although use of as many as 53% of antimicrobials (26/49) surveyed was restricted, use in this category accounted for only 29% of all antimicrobial courses. Of 6376 antibiotic courses, 4101 (64%) were given intravenously and 2275 (36%) orally. Appropriateness of use of restricted drugs was lower (70%) than of unrestricted ones (84%, p<0.001). Of 24571 defined daily doses (DDD) given orally, 4587 (19%) were restricted, compared to 7264 (34%) of 21602 DDDs given intravenously (p<0.001). Antibiotic treatment in our hospital appears to be substantial and increasing, justifying efforts to improve appropriateness of therapy and improve clinical and financial results.

Administration, Oral↗
PubMed2001

Incidence of immunoglobulin G antibodies to Chlamydia pneumoniae in acute myocardial infarction patients.

BACKGROUND: Recent studies have suggested a possible association between Chlamydia pneumoniae infection and coronary heart disease. OBJECTIVES: To determine titers of antibodies to C. pneumoniae in patients with acute myocardial infarction compared with titers in several control groups. METHODS: This prospective case-control study investigated 209 individuals. We assessed the serum IgG antibody titers to C. pneumoniae in 57 consecutive patients admitted with AMI to our intensive coronary care unit during a 4 month period. A serum sample was drawn upon admission and after 6 weeks. Results were compared with those of four control groups: a) patients admitted with community-acquired pneumonia (n = 18), b) patients with community-acquired urinary tract infection (n = 42), c) patients with angiographically normal coronary artery disease (n = 44), and d) patients with stable coronary artery disease (n = 48). Serum immunoglobulin G antibody titers to C. pneumoniae were determined using standard micro-immunofluorescence technology. RESULTS: Of 57 patients with AMI, 32 (56%) had a high IgG titer to C. pneumoniae (> or = 1:256) on the initial test, which remained unchanged (62%) after 6 weeks. The percentage of patients with high titers was significantly lower in the control groups: 5 of 18 patients (28%) in the pneumonia group (P < 0.01), 11 of 42 (26%) in the urinary tract infection group (P < 0.01), 11 of 44 (25%) with normal coronary arteries (P < 0.01), and 17 of 48 (35%) with stable chronic ischemic heart disease (P < 0.05). CONCLUSION: The detection of high titers of IgG antibodies to C. pneumonia in many patients with AMI, compared to control groups, suggests that chronic Chlamydia pneumoniae infection plays a role in the pathogenesis of atherosclerosis and acute ischemic events.

Antibodies↗
PubMed2000

The use of the arterial line as a source for blood cultures.

OBJECTIVE: To determine the reliability of blood cultures obtained through indwelling arterial lines as compared to that of blood cultures obtained by venipuncture. DESIGN: A prospective observational study. SETTING: Six-bed mixed medical surgical intensive care unit (ICU) of a 550-bed university-affiliated medical center. MEASUREMENTS: During a 3-month period blood culture sets, when clinically indicated, were drawn in parallel from indwelling arterial catheters and one-time venipuncture and the results compared. Each blood sample consisted of 15 ml and was distributed equally between three blood culture bottles: aerobic, anaerobic and one aerobic resin-containing bottle. Blood culture results from the two sources were compared according to preset definitions. MAIN RESULTS: During the study period 90 parallel blood culture sets (540 bottles) were obtained from 36 patients. Forty-three (16%) venipuncture bottles were positive versus 88 (32%) arterial line culture bottles (p < 0.001). Of the parallel sets, 83% yielded equivalent results - either both sterile or both growing the same organism. Amongst the discordant sets, the arterial line cultures grew 37 gram-positive and 18 gram-negative isolates not found in venipuncture sets (i.e. 50% of 109 arterial line isolates), while only two gram-positive isolates were solely grown in venipuncture cultures (4% of all 55 venipuncture isolates, p < 0.001). On clinical correlation, all the gram-positive organisms in the discordant cultures were found not to reflect bacteremia, while five of the 18 gram-negative isolates (28%) grown only in arterial line cultures probably did reflect ongoing bacteremia. CONCLUSION: The results of blood cultures taken from the arterial line are frequently equivalent to those taken from venipuncture. When discordant, the growth of gram-positive bacteria almost certainly reflects contamination or arterial line colonization, whereas the growth of gram-negative bacteria may have to be considered as reflecting bacteremia.

Bacteremia↗
PubMed2000

Prospective surveillance of vancomycin-resistant enterococci in a neonatal intensive care unit.

A point-prevalence study of vancomycin-resistant enterococci colonization of the gastrointestinal tract in an Israeli hospital revealed that 14.7% of the 320 inpatients were colonized. Vancomycin-resistant enterococci colonization was detected in most departments except the neonatal intensive care unit. Hence, a prospective longitudinal study of the prevalence of vancomycin-resistant enterococci colonization in the neonatal intensive care unit was conducted. A rectal swab was obtained from every newborn on admission to the neonatal intensive care unit and once weekly thereafter until the patient was discharged. Enterococci were isolated and tested for susceptibility to vancomycin. A total of 84 neonates were enrolled and monitored on average for 3 weeks (SD +/- 3.9, range 1-20 weeks). Mean gestational age was 35.7 weeks (SD +/- 3.9, range 25-42 weeks), and mean birth weight was 2.4 kg (SD +/- 0.9, range 0.45-4.1 kg). Most patients had one or more of the known risk factors associated with colonization with vancomycin-resistant enterococci. Eighty percent of the patients received antibiotics during the study, and 14.3% received vancomycin. The median duration of vancomycin treatment was 12.5 days (SD +/- 16.8, range 5-55 days). Fifty-one of 84 (61%) patients acquired enterococci sensitive to vancomycin during the study period, but no newborn had vancomycin-resistant enterococci. Possible explanations for this finding may be physical isolation of the neonatal intensive care unit from the rest of the hospital, intrinsic differences in the bowel milieu of this age group and the lack of exposure to food and other environmental sources of vancomycin-resistant enterococci from the community.

Adolescent↗
PubMed2000

Assessment of knowledge of guidelines for the prevention of infective endocarditis amongst clinicians in a teaching hospital.

A significant minority of instances of endocarditis appear to be the result of invasive procedures performed in susceptible patients with underlying cardiac conditions. Absence, or inappropriate administration, of antimicrobial prophylaxis could expose the patient to the development of a potentially lethal infection. This study was formulated, therefore, to assess the knowledge of guidelines for the prevention of infective endocarditis among hospital-based physicians and surgeons. A multiple choice test was developed, including: (1) cardiac conditions at increased risk for development of infection; (2) procedures more likely to be associated with bacteraemia and endocarditis; and (3) type and route of antimicrobials prescribed when endocarditis prophylaxis is indicated. The quality of the test was determined in several ways. Success was defined as a pass rate of 11 of 18 questions (61%). The test was taken by 153 of 251 (60%) physicians employed by the hospital; 95 (62%) passed the test. No significant difference in success rates was found according to sex, professional status or medical school. Internists performed substantially better (with a pass rate of 41 of 53, 77%) than both paediatricians (13 of 26, 50%, P<0.05) and surgeons (41 of 74, 55%, P<0.01). The range of success varied from 100% to 36% according to specialty (P<0.001). The mean score was 69+/-21 in the study group and 94+/-10 in a control group of 20 infectious disease physicians (P<0.001). In conclusion, this study demonstrates the need for improved education of hospital-based clinicians regarding endocarditis prophylaxis recommendations.

Antibiotic Prophylaxis↗
PubMed2000

Practical guidelines for vancomycin usage, with prospective drug-utilization evaluation.

To strengthen guidelines for vancomycin use, practical guidelines were developed. A prospective survey was conducted of all patients receiving vancomycin during two 1-month periods, 1 year apart, during which significant improvements were noted. Practical guidelines may contribute to appropriateness of vancomycin use, serve as educational tools, and facilitate improved surveillance.

Drug Utilization Review↗
PubMed2000

Cefuroxime utilization evaluation: impact of physician education on prescribing patterns.

BACKGROUND: Cefuroxime is a second-generation cephalosporin antibiotic used widely for the treatment of various infections. OBJECTIVES: To assess the appropriateness of cefuroxime usage as well as the long-term impact of re-feeding the results to prescribing physicians. METHODS: Drug utilization evaluation involved three data-collecting periods, each comprising 6 weeks, during which all patients receiving cefuroxime were evaluated. Results of phase I were distributed to all physicians in a newsletter and departmental lectures; phase II was announced and conducted 6 months later. An identical phase III was unannounced and conducted one year after phase II. The study included all patients receiving cefuroxime during the three phases. The main outcome measure was appropriateness of initiation, and continuation beyond 3 days, of empirical treatment. Appropriateness was determined according to a prepared list of indications based on the literature and the hospital's protocols. RESULTS: Cefuroxime was initiated appropriately in 104 of 134 patients (78%) in phase I, in 85 of 100 (85%) in phase II, and in 93 of 100 (93%) in phase III (P < 0.001). Cefuroxime was continued appropriately after 3 days in 58/134 (43%), 57/100 (57%) and 70/100 (70%) respectively (P < 0.001). The total number of appropriate treatment days out of all treatment days increased from 516 of 635 (81%) in phase I, to 450 of 510 (88%) in phase II, to 485 of 509 (95%) in phase III (P < 0.001). The principal reason for cefuroxime usage was community-acquired respiratory tract infection. CONCLUSION: Drug utilization evaluation may provide valuable data on the usage of a particular drug. This information, once re-fed to physicians, may improve utilization of the particular drug. This positive effect may be prolonged beyond the immediate period of observation.

Cefuroxime↗
PubMed1999

Ten-year follow-up study of hepatitis B virus infection and vaccination status in hospital employees.

We sought to determine the incidence of infection with hepatitis B virus (HBV) amongst hospital employees over a 10-year period and to assess the extent and efficacy of vaccination against HBV in this population. In 1984 a cohort of 301 hospital employees was tested for hepatitis B surface antibody (anti HBs), hepatitis B core antibody (anti HBc), and hepatitis B surface antigen (HBsAg). Ten years later, 160 (53%) of these workers remained at the hospital and were re-tested. In addition, they were tested for hepatitis C virus antibody (anti HCV). Records of the hospital vaccination program were inspected to determine the rate and effectiveness of vaccination in these workers. Over the ten year period two of the 160 retested workers (1.25%) had sero-converted to anti HBc positive, yielding an incidence density of 0.27 cases per 100 person-years exposed in unvaccinated workers. While the overall seroprevalence of anti HBc did not change significantly between 1984 (81/301, 27%) and 1994 (39/160, 24%), it was much greater than that of the general population (10%). A significantly greater percentage of Jews of Sephardi ancestry (22/65, 34%) were positive for anti HBc than those of Ashkenazi ancestry (15/90, 17%, P < 0.05). In addition, doctors were found to be less likely to be anti HBc positive than nurses (4% vs. 25%, respectively, P < 0.01). Two cases of anti HCV positivity were discovered yielding a prevalence of 1.25% in the 1994 cohort as compared to 0.15% in the population of healthy blood donors. Of the 93 employees of the 1994 cohort eligible for vaccination (i.e., anti HBc-negative and employed in an occupation involving potential exposure to HBV), 53 (57%) had received vaccination and showed protective antibody titers (anti HBs > or = 10 i.u./ml). 17/52 workers with documented vaccinations (33%) did not have detectable antibody levels one to eight years after vaccination. In conclusion, the seroprevalence of anti HBc and anti HCV is significantly higher in this cohort of hospital employees than in the general population. The relatively low vaccination rate among at-risk personnel emphasizes the need for more effective vaccination programs.

Adult↗
PubMed1999

In-vitro activity of cefepime and other broad-spectrum antimicrobials against several groups of gram-negative bacilli and Staphylococcus aureus.

The in vitro activity of cefepime was compared with that of amikacin, ceftazidime, imipenem, ciprofloxacin, and piperacillin-tazobactam by using the E-test against five groups of carefully selected organisms: Klebsiella pneumoniae (68 isololates), Pseudomonas aeruginosa (62), methicillin-susceptible Staphylococcus aureus (MSSA) (60), and two groups of Enterobacteriaceae (60 and 62 isolates, respectively). The bacteria were subdivided according to whether the infection was nosocomial or community-acquired, applying accepted and predefined criteria. These isolates were obtained from patients admitted to our medical center throughout 1998. We retrospectively compared antimicrobial susceptibilities of the study sample with those of the +/- 3000 bacterial strains isolated from blood stream infections since 1990: the study sample appeared to represent adequately the clinical databank. Presence of extended-spectrum beta-lactamase (ESBL) was determined in all groups of Enterobacteriaceae with the ESBL screening E-test strip. Of the 252 Gram-negative bacilli tested, 242 (96%) were susceptible to cefepime, whereas only 168 (67%) were susceptible to ceftazidime, 211 (84%) to amikacin, and 220 (87%) to piperacillin-tazobactam (p < 0.001). Imipenem was slightly superior to cefepime with only seven isolates resistant (3%), six of which were P. aeruginosa. Cefepime was more active against Enterobacteriaceae than ceftazidime (93% vs. 72%, p < 0.001). This superiority was most evident against nosocomial strains of K. pneumoniae, against which cefepime was > three times more active than ceftazidime. The high level of resistance seen in nosocomial isolates of K. pneumoniae is consistent with high rates of ESBL production (69%, compared with 15-26% in other Enterobacteriaceae). The MIC90 of cefepime to methicillin-sensitive S. aureus was 1.5 micrograms/mL, whereas that of ceftazidime was 4 micrograms/mL; the susceptibility rate of both was 100%. In conclusion, cefepime possesses in vitro potencies against MSSA and current clinical strains of Gram-negative bacilli, many of which harbor resistance to other antimicrobial agents. Hence, it seems very suitable for empiric coverage of serious nosocomial infections.

Cefepime↗
PubMed1999

Cost-effectiveness of blood cultures for adult patients with cellulitis.

To assess the cost-effectiveness of blood cultures for patients with cellulitis, a retrospective review was conducted of clinical and microbiological data for all 757 patients admitted to a medical center because of community-acquired cellulitis during a 41-month period. Blood cultures were performed for 553 patients (73%); there were a total of 710 blood samples (i.e., a mean of 1.3 cultures were performed per patient). In only 11 cases (2.0%) was a significant patient-specific microbial strain isolated, mainly beta-hemolytic streptococci (8 patients [73%]). An organism that was considered a contaminant was isolated from an additional 20 culture bottles (3. 6%). The cost of laboratory workup of the 710 culture sets was $36, 050. Isolation of streptococci led to a change from empirical treatment with cefazolin to penicillin therapy for 8 patients. All patients recovered. In conclusion, the yield of blood cultures is very low, has a marginal impact on clinical management, and does not appear to be cost-effective for most patients with cellulitis.

Adolescent↗