Milleri group streptococcus--a stepchild in the viridans family.

The purpose of this investigation was to provide a comprehensive review of the pathogenic role and spectrum of disease of milleri group streptococci, with special attention to bloodstream invasion and to possible differential roles among the three species. All consecutive isolates of milleri group streptococci from any anatomic source, during a 37-month period, in a tertiary care teaching hospital in Tel-Aviv, Israel, were thoroughly investigated. Identification to the species level was performed by an automated system.Streptococcus anginosus constituted 82% of the 245 patient-unique isolates from hospitalized patients. All nonurinary isolates were involved in pyogenic infections mostly originating from the gastrointestinal tract, with bacteremia in 28 cases. The 71 urinary isolates represented either urinary tract infection or nonsignificant bacteriuria. No specific association could be detected between species and the infection site, except for a higher relative representation of Streptococcus constellatus in bacteremia. Milleri group streptococci are common in clinical practice and play a different pathogenic role to other viridans streptococci. Due to their invariable association with pyogenic processes, their presence in blood warrants immediate focus identification. In addition, they have a previously unappreciated clinical niche concerning urinary tract infection. The identification of viridans streptococci to the species level is of paramount clinical significance.

Are dental procedures an important risk factor for infective endocarditis? A case-crossover study.

Although infective endocarditis (IE) is often reported to develop following dental treatment, no published data have accurately defined the risk of IE from dental procedures. The purpose of this study was to examine whether dental procedures constitute significant risk factors for endocarditis. The study population was composed of 170 hospitalized patients with infective endocarditis. The frequency of dental procedures during the 3-month period immediately before admission was compared with the frequency of such procedures during earlier 3-month control periods (when no endocarditis developed), using the case-crossover design. Thirty-four out of 98 patients with available information (35%) had had 81 dental procedures during the 2 years before hospitalization, 12 (12%) of whom had had 14 procedures during the 3 months before admission. The number and types of dental procedures performed during this 3-month period were not statistically different from those carried out during any earlier 3-month period, which served as a control period. Dental procedures do not significantly increase the risk of IE.

Impact of multi-drug-resistant Acinetobacter baumannii on clinical outcomes.

We conducted a retrospective matched cohort study to examine the impact of isolation of multi-drug-resistant (MDR) Acinetobacter baumannii on patient outcomes. Cases from whom MDR A. baumannii was isolated in a clinical culture (n = 118) were compared with controls from whom MDR A. baumannii was not isolated (n = 118). Cases and controls were matched according to ward, calendar month of hospitalization, and duration of hospitalization before culture. The following outcomes were compared in multivariable analysis: in-hospital mortality, length of stay, need for mechanical ventilation, and functional status at discharge. MDR A. baumannii was determined to be a pathogen in 72% of cases. In 36% of cases, the patient died, versus 21% of controls (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.17-4.16, P = 0.014). Median length of stay for surviving cases was 17 days, versus 11 for surviving controls (multiplicative effect 1.55, 95% CI 0.99-2.44, P = 0.057). Fifty-two percent of cases required mechanical ventilation, versus 25% of controls (OR 3.72, 95% CI 1.91-7.25, P<0.001); 60% of surviving cases were discharged with reduced functional status, versus 38% of controls (OR 4.4, 95% CI 1.66-11.61, P = 0.003). In multivariable analysis, clinical isolation of MDR A. baumannii remained a significant predictor of mortality (OR 6.23, 95% CI 1.31-29.5, P = 0.021), need for mechanical ventilation (OR 7.34, 95% CI 2.24-24.0, P<0.001), and reduced functional status on discharge (OR 7.93, 95% CI 1.1-56.85, P = 0.039). Thus, MDR A. baumannii acquisition is associated with severe adverse outcomes, including increased mortality, need for mechanical ventilation, and reduced functional status.

The possible significance of Clostridium spp. in blood cultures.

The significance of Clostridium spp. in blood cultures was evaluated by two methods. In the first part of the study, a group of 80 patients with Clostridium spp. bacteraemia was compared with a group of 100 patients with Bacillus spp. in blood cultures, making the assumption that Bacillus almost invariably represents contamination (pseudobacteraemia). Significant differences were found between the two groups, suggesting that growth of Clostridium did not represent pseudobacteraemia. Patients with Clostridium bacteraemia were older, had a higher frequency of gastrointestinal disease (especially colorectal tumours), were associated more frequently with polymicrobial bacteraemia, and had a higher mortality rate. In the second part of the study, each of the 80 cases of Clostridium bacteraemia was evaluated individually for clinical relevance by an infectious diseases expert. In two-thirds of the cases, isolates of Clostridium from blood were considered to be of clinical relevance, whereas in one-third of cases, the clinical significance of this finding was doubtful. It was concluded that growth of Clostridium spp. in blood cultures, even in the absence of one of the histotoxic syndromes, is often of clinical significance, and that such findings should be properly evaluated and not ignored.

Acinetobacter baumannii: emergence and spread in Israeli hospitals 1997-2002.

The incidence of multi-drug-resistant Acinetobacter baumannii bloodstream infections (BSIs) increased two- to four-fold in three Israeli hospitals between 1997 and 2002, accounting for 3.5-18% of all hospital-acquired BSIs. This was associated with increasing carbapenem resistance reaching 35-54%, and by a dramatic increase in carbapenem consumption. In-hospital fatality rates ranged between 47% and 58% and were significantly higher than those seen with other nosocomial Gram-negative pathogens. A. baumannii was not restricted to intensive care units, but had spread to all hospital wards. Multi-drug-resistant A. baumannii has the potential to reach endemicity in hospitals and warrants more vigorous and innovative efforts to limit its spread.

Unexpected hospital-acquired bacteraemia in patients at low risk of bloodstream infection: the role of a heparin drip.

Following a cluster of cases of unexpected hospital-acquired bacteraemia suspected to be related to an intravenous (iv) heparin drip, all cases of hospital-acquired primary bloodstream infection (BSI) in patients at low risk of bacteraemia were analysed over a four-year period. Ninety-six bacteraemic patients (6%) from 1618 episodes of hospital-acquired bacteraemia had a peripheral iv line as the only risk factor. These patients were divided into two groups: 60 patients with phlebitis and 36 without local signs of inflammation. Baseline features of the two groups were comparable, but in univariate and multivariate analysis, a significant association was found between iv heparin use, predominance of Gram-negative organisms (especially Klebsiella, Serratia and Enterobacter species), and absence of phlebitis. In spite of clear statistical association, however, the means by which the heparin solution became contaminated with Gram-negative organisms remained unknown. Following implementation of infection control methods concerning heparin handling, no more cases occurred. Unexpected hospital-acquired Gram-negative bacteraemia in patients with peripheral iv lines should prompt investigation of potential infusate-related infection, especially in patients without phlebitis and those receiving iv heparin.

West Nile fever outbreak, Israel, 2000: epidemiologic aspects.

From August 1 to October 31, 2000, 417 cases of West Nile (WN) fever were serologically confirmed throughout Israel; 326 (78%) were hospitalized patients. Cases were distributed throughout the country; the highest incidence was in central Israel, the most populated part. Men and women were equally affected, and their mean age was 54+/-23.8 years (range 6 months to 95 years). Incidence per 1,000 population increased from 0.01 in the 1st decade of life to 0.87 in the 9th decade. There were 35 deaths (case-fatality rate 8.4%), all in patients >50 years of age. Age-specific case-fatality rate increased with age. Central nervous system involvement occurred in 170 (73%) of 233 hospitalized patients. The countrywide spread, number of hospitalizations, severity of the disease, and high death rate contrast with previously reported outbreaks in Israel.

Clinical characteristics of the West Nile fever outbreak, Israel, 2000.

West Nile (WN) virus is endemic in Israel. The last reported outbreak had occurred in 1981. From August to October 2000, a large-scale epidemic of WN fever occurred in Israel; 417 cases were confirmed, with 326 hospitalizations. The main clinical presentations were encephalitis (57.9%), febrile disease (24.4%), and meningitis (15.9%). Within the study group, 33 (14.1%) hospitalized patients died. Mortality was higher among patients >70 years (29.3%). On multivariate regressional analysis, independent predictors of death were age >70 years (odds ratio [OR] 7.7), change in level of consciousness (OR 9.0), and anemia (OR 2.7). In contrast to prior reports, WN fever appears to be a severe illness with high rate of central nervous system involvement and a particularly grim outcome in the elderly.

West Nile encephalitis in Israel, 1999: the New York connection.

We describe two cases of West Nile (WN) encephalitis in a married couple in Tel Aviv, Israel, in 1999. Reverse transcription-polymerase chain reaction performed on a brain specimen from the husband detected a WN viral strain nearly identical to avian strains recovered in Israel in 1998 (99.9% genomic sequence homology) and in New York in 1999 (99.8%). This result supports the hypothesis that the 1999 WN virus epidemic in the United States originated from the introduction of a strain that had been circulating in Israel.

Epidemiology of vascular catheter-related bloodstream infections in a large university hospital in Israel.

Intravascular catheter-related infection and associated bacteraemia constitute a serious and increasing problem among nosocomial infections. As a part of an ongoing survey of positive blood cultures, all catheter-related bloodstream infections (CR-BSI) were reviewed in the authors' Medical Center in 1996, in order to evaluate the magnitude and seriousness of this problem. The largest group (28%) of hospital-acquired bacteraemia by 1 source of infection during 1996 was CR-BSI, identified in 110 patients with 126 episodes. The vascular line was central in 83 (66%), peripheral in 24 (19%), tunnelled in 18 (14%) and arterial in 1 (1%). Among the 83 central CR-BSI no sign of local inflammation was detected in 65%. Gram-positive and gram-negative bacteria shared equal parts among the 145 blood isolates; Staphylococcus aureus was the most common species (43/145, 30%) followed by Klebsiella pneumoniae (15/145, 10%); 11 (8%) isolates were Candida species. Fungal isolates were more common among tunnelled catheter infections than among others (6/18, 33% vs. 5/108, 5%, p < 0.001). Crude mortality was 35% (38/110), while attributable mortality was 14% (15/110), mostly associated with central line infection. Catheter-associated bacteraemias cause significant morbidity and mortality, and have become the most common source of hospital-acquired bacteraemia. There is a need to implement more effective infection-control measures and more advanced technologies in an effort to reduce this unacceptably high incidence.

Clinical significance and antibiotic resistance patterns of Leminorella spp., an emerging nosocomial pathogen.

Although Leminorella spp., members of the family Enterobacteriaceae, were previously isolated from feces and urine specimens, clinical correlates have not been studied. We conducted a retrospective study to investigate the clinical significance and disease spectrum of these organisms, as well as their antibiotic susceptibility patterns. Identification and susceptibility testing were performed by an automated system. Eighteen cases were identified retrospectively during a 28-month period (1/97 to 4/99), representing an incidence of 11 cases per 100,000 patient admissions. The medical records of 14 patients were reviewed. The average patient age was 67 years, and 78% were males. Patients had multiple and diverse underlying conditions which might have predisposed them to infection. Leminorella spp. were classified as definite pathogens in 43% of the cases, probable pathogens in 29%, and possible pathogens in 21%. In one case of asymptomatic bacteriuria, the isolate had no clinical significance. All infections but one were nosocomial. Clinical syndromes included urinary tract infection in six patients, surgical site infection in three patients, and primary bacteremia, peritonitis, respiratory tract infection, and soft tissue infection in one patient each. Isolates were uniformly susceptible to imipenem. Other beta-lactam agents had poor activity against the isolates. We conclude that Leminorella spp. are significant nosocomial pathogens that are capable of causing a variety of clinical syndromes and are resistant to multiple antibiotic agents.

Epidemiology of ceftazidime-resistant Klebsiella pneumoniae in a large university hospital in Tel Aviv.

BACKGROUND: An increase in multiple drug-resistant Klebsiella pneumoniae due to extended spectrum beta-lactamase production has recently been reported from many centers around the world. There is no information in the literature regarding this problem in Israel. A high prevalence of ceftazidime-resistant K. pneumoniae was noted in our Intensive Care Unit in the first few months of 1995. OBJECTIVE: To describe the epidemiology of ceftazidime-resistant K. pneumoniae in our medical center, as representing the situation in tertiary care hospitals in Israel. METHODS: We vigorously restricted the use of ceftazidime in the ICU and enforced barrier precautions. The susceptibility rate of K. pneumoniae was surveyed in the ICU and throughout the hospital before and after the intervention in the ICU. RESULTS: Following the intervention, the susceptibility rate of K. pneumoniae increased from 11% (3/28) to 47% (14/30) (P < 0.01) among ICU isolates, from 55% (154/280) to 62% (175/281) (P = 0.08) among total hospital isolates, and from 61% (50/82) to 74% (84/113) (P < 0.05) among total hospital blood isolates, although no additional control measures were employed outside the ICU. CONCLUSIONS: The epidemiology of ceftazidime-resistant K. pneumoniae in our medical center is similar to that reported from other centers around the world. Early awareness to the emergence of this resistance, identification of the source of the epidemic, and prompt action at the putative source site may reduce the rate of acquisition and spread of such resistance inside and outside of the source unit.

Pseudomonas aeruginosa bacteremia: an analysis of 123 episodes, with particular emphasis on the effect of antibiotic therapy.

OBJECTIVES: To review current experience with Pseudomonas aeruginosa bacteremia and compare outcome of patients treated with single-drug, versus combination therapy. METHODS: The charts of all patients with P. aeruginosa bacteremia between 1990 and 1992 were reviewed, and pertinent demographic, clinical, and bacteriologic data were retrieved. In addition, similar data were collected from a series of patients with P. aeruginosa bacteremia from the literature of the past 20 years. RESULTS: One hundred and twenty-three episodes of P. aeruginosa bacteremia in 121 patients were identified. Most patients were older than 70 years, had at least one underlying condition, and had acquired the infection in the hospital. Attributable mortality was 34%. After exclusion for early mortality and inappropriate therapy, 57 patients remained eligible for comparison of outcome according to therapy protocol. Mortality from infection was equal between the group of 42 patients who received monotherapy and the 15 patients who received combination therapy (14% and 13%, respectively). The literature review revealed eight articles describing 21 to 410 episodes of Pseudomonas bacteremia. The clinical characteristics of these series did not differ significantly from those of the present series. CONCLUSIONS: Incidence, epidemiology, clinical characteristics, and outcome of pseudomonas sepsis did not change significantly over the past 2 decades. Appropriate monotherapy was as effective as combination drug therapy for individuals with pseudomonas bacteremia surviving the first 2 days of infection.

A randomized crossover study of disposable thermometers for prevention of Clostridium difficile and other nosocomial infections.

OBJECTIVE: To test the hypothesis that use of disposable thermometers would result in lower rates of nosocomial Clostridium difficile diarrhea and of total nosocomial infections, compared with electronic thermometers. DESIGN: Prospective randomized crossover trial. SETTING: A 700-bed university hospital providing primary and tertiary care. PATIENTS: All patients admitted to a group of 20 inpatient nursing units. INTERVENTIONS: 20 nursing units were randomized into two groups. One group randomly was assigned exclusive use of single-use disposable thermometers for patient temperature measurement, and the other group was assigned exclusive use of electronic thermometers. After 6 months, the assignments were reversed. MAIN OUTCOME MEASURES: Rates of C difficile infections, total nosocomial diarrheal episodes, and total nosocomial infections were prospectively followed in each study unit over 11 months. RESULTS: 26,350 patients were admitted to the study units and hospitalized for 120,529 patient days. There were 947 nosocomial infections (7.86 per 1,000 patient days). Nosocomial C difficile-associated diarrhea defined by positivity to both toxin B (titer > or = 1:10) and toxin A was detected in 32 patients (3.4% of all nosocomial infections). A significantly lower rate of nosocomial C difficile-associated diarrhea was observed with disposable thermometer use (0.16 per 1,000 patient days) compared with electronic thermometer use (0.37 per 1,000 patient days, relative risk [RR] = 0.44; 95% confidence interval [CI95], 0.21-0.93, P = .026). There was no difference in overall rates of nosocomial infection between the disposable and electronic groups (8.03 and 7.68 infections per 1,000 patient days, respectively; RR, 1.04; CI95, 0.92-1.19; P = .52) or in the overall rate of nosocomial diarrhea (3.34 and 3.40 per 1,000 patient days, respectively; RR, .98; CI95, 0.81-1.19; P = .87). CONCLUSIONS: The incidence of nosocomial C difficile diarrhea was reduced significantly by using single-use, disposable thermometers as compared with electronic thermometers, but there was no effect on either the overall rate of nosocomial diarrhea or the rate of total nosocomial infections.

Diagnosis of vascular catheter-related bloodstream infection: a meta-analysis.

Catheter-related bloodstream infections increased in incidence during the past decade, causing significant morbidity, mortality, and excess hospital costs. Absence of inflammation at the catheter site in most cases makes clinical diagnosis uncertain. The relative accuracy and cost-effectiveness of different microbiologic tests for confirming that bloodstream infection is catheter related have remained unclear. A meta-analysis of published studies was conducted regarding the accuracy of diagnostic test methods using pooled sensitivity and specificity and summary receiver operating characteristic (ROC) curve analysis. The cost for each test was estimated by methods published by the College of American Pathologists. Costs of catheter replacement and antibiotic therapy for false positive results were included in the cost per accurate test result. Twenty-two studies evaluating six test methods met inclusion criteria for the meta-analysis. Accuracy increased in ROC analysis for catheter segment cultures with increasing quantitation (P = 0.03) (i.e., quantitative > semiquantitative > qualitative) largely due to an increase in specificity. The highest Youden index (mean = 0.85) was observed with quantitative catheter segment culture, the only method with pooled sensitivity and specificity above 90%. For blood culture methods, there was no statistically significant trend toward increased accuracy. The unpaired quantitative catheter blood culture offered the lowest cost per accurate test result but was only 78% sensitive. In conclusion, quantitative culture was the most accurate method for catheter segment culture, and unpaired quantitative catheter blood culture was the single most cost-effective test, especially for long-term catheters.

Q fever endocarditis in Israel and a worldwide review.

The worldwide epidemiology and population-based incidence of Q fever endocarditis (QFE) have been less well studied than those for uncomplicated Q fever. An exhaustive literature review revealed 408 patients with QFE reported between 1949 and 1994, mostly from 3 large geographic areas. Underlying valvular heart disease was almost invariably present, and 38% had prosthetic valves. The most common clinical manifestations were fever and congestive heart failure. The mortality rate dropped over the years from 65% to 25%, but a meta-analysis of published data showed the death rate to be significantly lower among patients receiving combination therapy (12/65, 18%), as compared to patients treated with tetracycline alone (18/41, 44%, p = 0.005). A 10-year (1983-1992) retrospective nationwide survey of QFE in Israel revealed 35 patients with QFE, representing an annual incidence of 0.75 cases per 1 million population. Underlying heart disease, clinical manifestations and outcome in the Israeli group were not substantially different from those described in the world literature. The current state-of-the-art clinical approach includes early diagnosis, prompt initiation of combination therapy for at least 3 years, and long-term clinical and serologic follow-up. Adherence to these rules might have contributed to the improved prognosis in recent years.

Sternal wound infection: our experience with 200 cases.

More than 200 patients with sternal wound infections have been treated in the Plastic Surgery Department of our Medical Center over the years 1984-1993. Most of these were referrals from other hospitals. In recent years, the cases have become more severe, partially due to the fact that cardiac surgeons tend to operate older and sicker patients more readily than they previously did. 80% of these were post coronary bypass surgery, and the others heart and heart-lung transplants, repair of congenital heart anomalies, valve replacements etc. Several of the cases were cardiac surgery re-do's. Risk factors for developing this complication, such as diabetes, obesity, technical errors of sternal incision, prolonged intubation, the use of aortic balloon, etc. will be discussed. Many of our earlier patients had chronic fistulae following conservative therapy with old treatment modalities. In recent years, patients are usually referred at the acute stage. Most patients undergo removal of sternum and ribs. Previously, reconstruction included mainly transfer of the rectus ahdominis muscle, whereas lately the pectoralis muscles is utilized. Omentum was used in only one case. The importance of pre-operative imaging procedures has been thoroughly studied in our series. Especially important is the definition of the extent of the infection, and localization of foreign bodies causing chronic infections, such as suture material, epicardial electrodes etc. A change in infectants has also been noticed. In the first half of the study period, Pseudomonas aeruginosa comprised at least 40%.(ABSTRACT TRUNCATED AT 250 WORDS)

The significance of urine culture with mixed flora.

Urine cultures that contain more than one organism are usually considered contaminated. The frequency with which such growth truly represents mixed infection is unknown. Surprisingly few studies have evaluated the clinical significance of polymicrobial growth from urine. Such significance was demonstrated in these studies either by recovering the same combination of microorganisms from blood and urine, in cases of urosepsis, or by the reproducibility of the same mixture of bacteria from sequential urine cultures. In certain clinical settings, polymicrobial bacteriuria is not only frequently significant but its overall clinical impact seems to be substantial. Bacteriuria associated with long-term catheterization, the most common nosocomial infection in American medical care facilities, is predominantly polymicrobial. Symptomatic urinary tract infection is a common outcome of such bacteriuria and has been associated with increased risk for bloodstream infections and excess mortality. Early species identification and antimicrobial susceptibility testing of each urinary isolate may be of paramount benefit to the care of these patients. We believe that in properly collected urine samples, multiple growth often represents true mixed infection and should therefore be completely evaluated.