Single Positive Blood Culture Research Articles

Bloodstream Infections With Vancomycin-Resistant Enterococci

To describe the population in whom bloodstream infections with vancomycin-resistant enterococci occur and the clinical and microbiologic features of infection. From June 1, 1991, to January 31, 1994, 73 patients with bloodstream infections with vancomycin-resistant enterococci were identified by retrospective review of hospital charts and microbiology records. Fifty-two (73%) of 71 patients with evaluable data were hospitalized in an intensive care, unit, the adult oncology unit, or the acquired immunodeficiency syndrome unit. Before the development of the bloodstream infection with vancomycin-resistant enterococci, patients were hospitalized and received antibiotics for a median of 26 and 25.5 days, respectively. A hematologic malignancy, respiratory failure, or renal failure requiring dialysis was present in 59 patients (83%). Acute Physiology and Chronic Health Evaluation II scores of the patients ranged from 6 to 35 (median, 17). Forty-five (63%) of the patients died. Compared with 37 patients who had only a single positive blood culture, the 34 patients with 2 or more blood cultures positive for vancomycin-resistant enterococci more often were neutropenic or had acquired immunodeficiency syndrome (74% vs 35%; P = .002). Bloodstream infections with vancomycin-resistant enterococci predominantly affect severely ill patients who have received extensive antibiotic treatment during a prolonged hospitalization. Immunocompromised patients are more likely to have a persistent blood-stream infection with vancomycin-resistant enterococci.

Secular trends in mortality associated with bloodstream infections in 4268 patients hospitalized in a cancer referral left between 1975 and 1989

OBJECTIVE: To study the trends in mortality over 15 years in hospitalized cancer patients with bloodstream infection. METHODS: The yearly incidence rates and risk of death, by type of microorganism, were calculated for 4268 cancer patients hospitalized between 1975 and 1989 in a French cancer referral center. The relative risk of death (RR) associated with each type of microorganism was estimated using the proportional hazards model, taking into account age, hospital ward, underlying disease, geographical origin and year of the first positive blood culture. RESULTS: The incidence of these infections was five-fold higher in 1989 than in 1975. The largest increases were for coagulase-negative staphylococci (CNS), yeasts and Staphylococcus aureus. For the 3756 patients who had a single-microorganism bloodstream infection, the risk of death compared with that of patients with CNS infection was significantly increased in those with Pseudomonadaceae (RR=5.0), yeasts (RR=3.4), Enterobacteriaceae (RR=3.2), S. aureus (RR=2.8) and streptococci (RR=2.1). The risk of death was not significantly different between patients with a single or several positive blood cultures nor between those with nosocomial or non-nosocomial infections. When the study period was divided in two time periods (1975 to 1982 vs 1983 to 1989), a significant variation (p=0.001) in risk of death associated with the different microorganisms was observed. Most risks were lower from 1983 to 1986 than before 1982. This decrease reached 60% for both S. aureus and Pseudomonadaceae. CONCLUSIONS: These data support of continuing use of aggressive empirical antimicrobial therapy for cancer patients with fever.

Incidence of bacteraemia or fever during transoesophageal echocardiography: a prospective study of 82 patients.

The incidence of bacteraemia during transoesophageal echocardiography (TEE) was evaluated in a prospective study of 82 consecutive patients. Three series of blood cultures were carried out for each patient: from group 1 (n = 44), prior to the examination, at the end of the examination and 15 min afterwards. For group 2 (n = 38), blood cultures were performed prior to the examination, 10 min after the start and immediately after the end. A single positive blood culture was detected in two patients. For the first patient, blood culture at the end of the examination demonstrated Corynebacteria, and for the second, Staphylococcus epidermidis was identified on cultures taken during the examination. During the first 24 h, a transient subfebrile temperature was recorded in 15% of the patients, including the patient with the Corynebacteria-positive blood culture. By mid-term (6 months) no patient had developed endocarditis. Our findings suggest that antibiotic prophylaxis during TEE is not warranted.

Value of the hybritech ICON Candida assay in the diagnosis of invasive candidiasis in high-risk patients

A total of 314 sera from 114 patients at risk for invasive candidiasis were analyzed for the presence of antigenemia using the Hybritech enzyme immunoassay (EIA) for detection of Candida mannan in serum (ICON) Candida Assay, Hybritech Inc., San Diego, CA). Fourteen patients (12%) had invasive candidiasis documented by positive blood cultures, deep biopsy culture, and histopathology or autopsy, and five patients had probable invasive candidiasis based on a single positive blood culture and no additional signs of candidiasis. Nine patients had candiduria, 43 patients had mucous membrane colonization, 25 patients were not colonized but received empiric amphotericin B, and 18 patients were not colonized and not treated with amphotericin B. All sera were enzymatically extracted, heat treated, and reacted in a solid-phase sandwich EIA. Test results were read visually and with the ICON reader. The sensitivity and specificity of the mannan EIA in detection of documented invasive candidiasis was 86% and 92%, respectively. The positive predictive value was 60% and the negative predictive value was 98%. Among all patients with invasive candidiasis (documented plus probable), the sensitivity was 68%, the positive predictive value 62%, and the negative predictive value 94%. Specimens were positive within 3 days of the first positive culture in 11 (79%) of 14 patients with documented invasive candidiasis.

Bacteraemia caused by non- aeruginosa Pseudomonas species in a cancer centre

Fifty-one episodes of bacteraemia due to Pseudomonas species other than Pseudomonas aeruginosa occurring between 1980 and 1990 in a Belgian cancer centre were reviewed. This corresponded to an incidence of 0·62 1000 admissions, or 1·5% of all bacteraemic episodes. Twenty-nine episodes, each with several positive blood culture sets were considered clinically significant, including six patients belonging to a well-documented outbreak of pseudobacteraemia with Xanthomonas maltophilia and associated with contaminated blood sampling tubes. The respiratory tract was the source in six (20·7%), an infected intravenous catheter in 10 (34·5%) and the source was unknown in seven (24·1%). Seven patients died from infection (24·1%). Twenty-three episodes with a single positive blood culture set were considered clinically not significant, although four of them were considered significant by the Centers for Disease Control (CDC) criteria because of the presence of symptoms and specific antibiotic treatment being administered. None of the patients with a single isolate died from infection despite the fact that 17 of 22 did not receive an effective antimicrobial agent. All isolates were susceptible to co-trimoxazole.

Bacteremia and Hemodialysis-Reply

In Reply. —We have categorized Dr Bernick's interesting letter as follows: Questions and Issues Raised by Bernick That Are Answerable Merely by Reading Article .—(1) As Table 1 shows, five of six patients had shaking chills with fever, three of six patients had emesis, one patient had leukocytosis, and one patient had a hypotensive episode. (2) As Results section and Table 1 show, four patients had a single positive blood culture for P stutzeri . The fourth patient had two positive blood cultures, one drawn from hemodialysis arterial line and second drawn later by venipuncture. (3) One patient had concommitant bacteremia with Pseudomonas fluorescens (which was also isolated from machine). (4) Bernick concludes that the emphasis should not be placed on environment but rather on personnel responsible for its management. 1(p1912) We merely repeat our last paragraph infection control procedures were emphasized to hemodialysis

Bacteremia in Children Following Upper Gastrointestinal Endoscopy or Colonoscopy

SummaryFifty children undergoing upper gastrointestinal endoscopy and 25 undergoing colonoscopy were studied prospectively with aerobic and anaerobic blood cultures for the development of bacteremia. Twenty‐six of the endoscopies and all the colonoscopies were done under general anesthesia. Cultures were obtained before, at 5 min, and at 30 min after the procedure. Only a single positive blood culture was obtained in an upper endoscopy patient. All cultures from the colonoscopy patients were negative. Biopsy or polypectomy were not important variables in the development of bacteremia. It is concluded that the risk of bacteremia in children following upper endoscopy or colonoscopy is minimal and should not be considered a contraindication to their performance.

Bacteremia in children following upper gastrointestinal endoscopy or colonoscopy.

Fifty children undergoing upper gastrointestinal endoscopy and 25 undergoing colonoscopy were studied prospectively with aerobic and anaerobic blood cultures for the development of bacteremia. Twenty-six of the endoscopies and all the colonoscopies were done under general anesthesia. Cultures were obtained before, at 5 min, and at 30 min after the procedure. Only a single positive blood culture was obtained in an upper endoscopy patient. All cultures from the colonoscopy patients were negative. Biopsy or polypectomy were not important variables in the development of bacteremia. It is concluded that the risk of bacteremia in children following upper endoscopy or colonoscopy is minimal and should not be considered a contraindication to their performance.

Torulopsis glabrata fungemia--a clinical pathological study.

The clinical findings, pathologic features, and outcome were investigated in 46 patients in whom Torulopsis glabrata was isolated in 131 specimens of blood. Nineteen of the patients had only a single positive blood culture and no evidence of systemic yeast infection, while 27 patients had a clinically significant fungemia based upon the occurrence of 2 or more positive blood cultures, or the combination of a positive blood culture and isolation of the organism from a closed body cavity or demonstration of the yeast in tissue sections. The predisposing factors to the development of fungemia included the presence of intravenous lines, indwelling Foley catheters, antibiotics and surgery, especially when the gastrointestinal tract was involved. Only 22% of patients received either steroids or cytostatic agents. Possible portals of entry were suggested by the prior isolation of the organism from urine, sputum, wounds, and central venous catheter tips in most of the patients. Twelve of 27 patients with clinically significant fungemia were treated. The initial mode of therapy in nine patients was removal of intravenous lines because of the clinical suspicion of catheter related sepsis. Seven of the patients improved rapidly and one more after amphotericin B was subsequently administered. Amphotericin B was the initial therapy in three cases. One patient was cured while another died of an unrelated infection. Five patients were not treated although the isolation of T. glabrata had been reported; the fact that the presence of the organism was felt to be unimportant was considered to be a factor in the delay of treatment. In the remaining 10 patients the organism was isolated only after the patient had died. Division of the patients into four groups based upon whether the individuals survived, died of unrelated disease, died with potentially lethal infection, or died with T. glabrata infection significantly contributing to death, revealed a spectrum of disease, certain signs of which appeared to be of predictive value as prognostic indices of survival and severity of the infection. Seven patients with transient fungemia experienced an acute episode of high spiking fever (greater than 102.5 degrees F), rigors and/or hypotension, six of whom improved after the intravenous catheter was removed, suggesting a catheter-related sepsis. In contrast, persistent low grade fever (less than 102.5 degrees F) characterized eight of the nine patients in whom T. glabrata infection was considered either potentially lethal, or contributing significantly to death. A deteriorating clinical course with organ failure was also associated with this latter category of patients. Catheter-induced specticemia was considered in only two patients in this category. The autopsy and clinical findings in this investigation as well as reported experimental studies suggest that T. glabrata is an organism of low virulence. The patients' underlying disease (e.g., neoplasia) and coexisting bacterial infection are the most important factors responsible for death.