scholarly journals Simple indictor of increased blood culture contamination rate by detection of coagulase-negative staphylococci

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kei Yamamoto ◽  
Kazuhisa Mezaki ◽  
Norio Ohmagari
Keyword(s):  
Blood Culture ◽  
Positive Blood Culture ◽  
Operating Characteristic ◽  
Characteristic Curve ◽  
Blood Cultures ◽  
Clinical Aspects ◽  
Contamination Rate ◽  
Coagulase Negative Staphylococci ◽  
Confidential Interval ◽  
Prediction Ability

AbstractCoagulase-negative staphylococci (CoNS) are the most frequent contaminating bacteria; therefore, we aimed to investigate an indicator of CoNS to predict the increase in blood culture contamination rate (ConR). We performed a retrospective study of selected patients, who underwent blood culture testing. Contamination was defined as the presence of either one of two or more sets of skin-resident bacteria, except for cases with a low likelihood of contamination based on clinical aspects. We calculated the monthly ConR [(total number of contaminated cases per month)/(total number of blood culture sets collected per month) × 100] and analysed the ConR prediction ability using the following four indicators: the number of CoNS-positive sets of blood cultures, cases with at least one CoNS-positive blood culture set, cases with only one CoNS-positive blood culture set, and cases of contamination by CoNS. Cases with CoNS-positive blood cultures correlated with ConR (r = 0.85). Although the area under the receiver operating characteristic curve for the number of cases with ConR ≥ 2.5 differed significantly from that of the number of cases contaminated by CoNS, the negative predictive value was high, reaching up to 95.5% (95% confidential interval 87.3–99.1). The number of CoNS-positive cases could help predict an increase in ConR ≥ 2.5.

Can the Number of Coagulase-negative Staphylococci Specimens Detected be an Alternative Quality Indicator to the Blood Culture Contamination Rate?

2021 ◽  
Author(s):  
Kei Yamamoto ◽  
Kazuhisa Mezaki ◽  
Norio Ohmagari
Keyword(s):  
Retrospective Study ◽  
Blood Culture ◽  
Receiver Operating Characteristic ◽  
Quality Indicator ◽  
Operating Characteristic ◽  
Blood Cultures ◽  
Contamination Rate ◽  
Coagulase Negative Staphylococci ◽  
Characteristic Curves ◽  
Receiver Operating Characteristic Curves

Abstract Purpose: Coagulase-negative staphylococci (CoNS) are the most frequent contaminating bacteria; hence, we aimed to investigate an indicator of CoNS to predict the increase in blood culture contamination rate (ConR).Methods: We performed a retrospective study of selected patients who underwent blood culture testing.Results: Cases with CoNS-positive blood cultures correlated with ConR (r=0.85). The area under the receiver operating characteristic curves for the number of cases with ConR ≥ 2.5 did not differ statistically from that of the number of cases contaminated by CoNS. Conclusion: The number of CoNS-positive cases could help predict an increase in ConR ≥2.5.

scholarly journals 81. Reducing Unnecessary Blood Cultures Through Diagnostic Stewardship

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S157-S157
Author(s):  
Sujeet Govindan ◽  
Luke Strnad
Keyword(s):  
Blood Culture ◽  
Positive Blood Culture ◽  
Cost Savings ◽  
Bloodstream Infections ◽  
Central Line ◽  
Blood Cultures ◽  
Coagulase Negative Staphylococci ◽  
Candida Sp ◽  
Daily Frequency ◽  
Oregon Health

Abstract Background At our institution, we learned the frequency of blood cultures was sometimes being changed from “Once” to “Daily” without a defined number of days. We hypothesized this led to unnecessary blood cultures being performed. Methods Over a 3 month period from 12/6/2019-3/6/2020, we retrospectively evaluated the charts of patients who had a blood culture frequency changed to “Daily”. We evaluated if there was an initial positive blood culture within 48 hours of the “Daily” order being placed and the number of positive, negative, or “contaminant” sets of cultures drawn with the order. Contaminant blood cultures were defined as a contaminant species, present only once in the repeat cultures, and not present in initial positive cultures. Results 95 unique orders were placed with 406 sets of cultures drawn from 89 adults. ~20% of the time (17 orders) the order was placed without an initial positive blood culture. This led to 62 sets of cultures being drawn, only 1 of which came back positive. 78/95 orders had an initial positive blood culture. The most common initial organisms were Staphylococcus aureus (SA) (38), Candida sp (10), Enterobacterales sp (10), and coagulase negative staphylococci (7). 43/78 (55%) orders with an initial positive set had positive repeat cultures. SA (26) and Candida sp (8) were most common to have positive repeats. Central line associated bloodstream infections (CLABSI) were found in 5 of the orders and contaminant species were found in 4 of the orders. 54% of the patients who had a “Daily” order placed did not have positive repeat cultures. The majority of the cultures were drawn from Surgical (40 orders) and Medical (35 orders) services. Assuming that SA and Candida sp require 48 hours of negative blood cultures to document clearance and other species require 24 hours, it was estimated that 51% of the cultures drawn using the "Daily" frequency were unnecessary. Cost savings over a year of removing the "Daily" frequency would be ~&14,000. Data from "Daily" blood culture orders drawn at Oregon Health & Science University from 12/6/2019-3/6/2020 Conclusion Unnecessary blood cultures are drawn when the frequency of blood cultures is changed to "Daily". Repeat blood cultures had the greatest utility in bloodstream infections due to SA or Candida sp, and with CLABSI where the line is still in place. These results led to a stewardship intervention to change blood culture ordering at our institution. Disclosures All Authors: No reported disclosures

scholarly journals “A Four-Leaf Clover” Sign for Rapid Identification of Coagulase-Negative Staphylococci by Gram Staining From Positive Blood Culture: A Cross-Sectional Study

2020 ◽  
Author(s):  
Takahiro Matsuo ◽  
Kuniyoshi Hayashi ◽  
Aki Sakurai ◽  
Masumi Suzuki Shimizu ◽  
Masaya Morimoto ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Regression Analysis ◽  
Blood Culture ◽  
Positive Predictive Value ◽  
Positive Blood Culture ◽  
Predictive Value ◽  
Blood Cultures ◽  
Coagulase Negative Staphylococci ◽  
Gram Staining ◽  
Sensitivity Specificity

Abstract Background: Coagulase-negative staphylococci (CoNS) are one of the most common contaminant microorganisms isolated from blood cultures. Few studies exploring the use of Gram staining to distinguish between Staphylococcus aureus (SA) and CoNS have been reported. Here, this study aimed to explore whether morphological features of Gram staining could identify SA or CoNS.Methods: This study was conducted at St. Luke’s International Hospital from November 2016 to September 2017. The positive blood cultures for which the Gram staining showed gram-positive cocci (GPC) in clusters were included in our study. The direct smear of Gram staining obtained from positive blood culture bottles were examined within 24 hours of positivity. We have identified and characterized the following two signs: “four-leaf clover (FLC)” if 4 GPC gathered like a planar four-leaf clover and “grapes” if the GPC gathered like grapes in a three-dimensional form. The number of fields with FLC and grapes signs in 10 fields per slide with ×1,000 power was counted, and the results in a total of 20 fields with ×1,000 power were combined. We performed a logistic regression analysis to assess whether these signs could serve as factors distinguishing between SA and CoNS. The predictive ability of these signs was evaluated based on the sensitivity, specificity, positive predictive value, and negative predictive value for CoNS via receiver operating curve analysis.Results: In total, 106 blood cultures for which Gram staining showed GPC in clusters were examined; 46 (43%) were SA, and 60 (57%) were CoNS samples. The result of multivariate logistic regression analysis showed that the FLC sign was a statistically significant marker of CoNS with an odds ratio of 1.31 (95 % confidential interval (CI): 1.07–1.61, p<0.05). In aerobic bottles, sensitivity, specificity, positive predictive value, and negative predictive value for CoNS were 0.67, 0.91, 0.92, and 0.65, respectively, and the value of area under the curve was 0.79 (95% CI: 0.67–0.91).Conclusions: To our knowledge, this is the first study to show that the FLC could be a rapid and useful indicator to identify CoNS in aerobic bottles. Thus, the presence of FLC sings could help clinicians to suspect the possibility of CoNS before the final identification by cultures.

scholarly journals Investigation of Antimicrobial Susceptibilities Among Bacteria Isolated from Blood Cultures in Hospitalized Patients, Tehran, Iran

2021 ◽  
Vol 16 (2) ◽  
Author(s):  
Shadi Aghamohammad ◽  
Maryam Nouri ◽  
Fatemeh Ashrafian ◽  
Mohtaram Sadat Kashi ◽  
Mehrdad Gholami ◽  
...  
Keyword(s):  
Blood Culture ◽  
Positive Blood Culture ◽  
Antimicrobial Agents ◽  
Clinical Laboratory ◽  
Blood Cultures ◽  
Multi Drug Resistance ◽  
National Committee ◽  
Coagulase Negative Staphylococci ◽  
Gram Positive ◽  
Cross Sectional

Background: Bacteremia is the status, which is detected via a positive blood culture test with no contamination. Centers for Disease Control and Prevention (CDC) indicates that direct medical procedures and total costs are significantly high. Antibiotic resistance can play a major role in the costs, which are related to the long duration of treatment. Objectives: The aim of this study was to investigate the rate and profiles of antimicrobial susceptibility of blood culture isolates from Tehran, Iran. Methods: In the current cross-sectional study, a total of 5,000 blood culture samples were collected from patients hospitalized in the Loghman General Hospital, Tehran, Iran, with positive blood culture results from 2012 to 2013. Susceptibility to antimicrobial agents was analyzed using National Committee for Clinical Laboratory Standards guidelines. Results: Coagulase-negative staphylococci (38.8%), Staphylococcus aureus (20.5%), Acinetobacter (11.9%), and Escherichia coli (11.7%) were the most frequent bacteria isolated from the blood cultures, collectively accounting for > 80% of the isolates. Of isolated microorganisms, 63.75% and 36.24% belonged to Gram-positive and Gram-negative bacteria, respectively. Moreover, 88% of the isolates were MRSA (oxacillin-/methicillin-resistant), and 7% were VRE (vancomycin-resistant). Conclusions: The most frequent isolated organisms were Gram-positive bacteria, and the rate of MDR (multi-drug resistance) was high. The results of the current study obviously indicate the misuse of antibiotic in society. National surveillance studies in Iran will be useful for clinicians to choose the right empirical treatment and will help control and prevent infections caused by resistant organisms.

Nosocomial Bacteremia Clinical Significance of a Single Blood Culture Positive for Coagulase-Negative Staphylococci

2005 ◽  
Vol 26 (8) ◽  
pp. 697-702 ◽  
Author(s):  
Benoît Favre ◽  
Stéphane Hugonnet ◽  
Luci Correa ◽  
Hugo Sax ◽  
Peter Rohner ◽  
...  
Keyword(s):  
Blood Culture ◽  
Clinical Significance ◽  
Positive Blood Culture ◽  
Blood Cultures ◽  
University Teaching ◽  
Coagulase Negative Staphylococci ◽  
Nosocomial Bacteremia ◽  
Single Positive ◽  
Clinically Significant ◽  
Culture Positive

AbstractObjectives:To describe the epidemiology of nosocomial coagulase-negative staphylococci (CoNS) bacteremia and to evaluate the clinical significance of a single blood culture positive for CoNS.Design:A 3-year retrospective cohort study based on data prospectively collected through hospital-wide surveillance. Bacteremia was defined according to CDC criteria, except that a single blood culture growing CoNS was not systematically considered as a contaminant. All clinically significant blood cultures positive for CoNS nosocomial bacteremia were considered for analysis.Setting:A large university teaching hospital in Geneva, Switzerland.Results:A total of 2,660 positive blood cultures were identified. Of these, 1,108 (41.7%) were nosocomial; CoNS were recovered from 411 nosocomial episodes (37.1%). Two hundred thirty-four episodes of CoNS bacteremia in the presence of signs of sepsis were considered clinically relevant and analyzed. Crude mortality and associated mortality were 24.4% and 12.8%, respectively. Associated mortality was similar among patients with one positive blood culture and those with two or more (16.2% vs 10.8%, respectively;P= .3). Mortality rates after bacteremia for patients with a single positive blood culture and for those with two or more were 15.3% and 7.0%, respectively, at day 14 (RR, 2.2; CI%, 0.87-5.46) and 20.8% and 11.3%, respectively, at day 28 (RR, 1.9; CI95, 0.9-3.8). On multivariate analysis, only age and a rapidly fatal disease were independently associated with death.Conclusion:CoNS bacteremia harbor a significant mortality and a single positive blood culture in the presence of signs of sepsis should be considered as clinically relevant.

scholarly journals Environmental Drivers of Bacillus-Positive Blood Cultures in a Cancer Hospital, Sapporo, Japan

2018 ◽  
Vol 15 (10) ◽  
pp. 2201 ◽  
Author(s):  
Takahiro Fujita ◽  
Hiroshi Nishiura
Keyword(s):  
Blood Culture ◽  
Positive Blood Culture ◽  
Characteristic Curve ◽  
Time Lag ◽  
Absolute Humidity ◽  
Blood Cultures ◽  
Japan Meteorological Agency ◽  
Environmental Drivers ◽  
Bacillus Species ◽  
Important Message

The Bacillus species is a well-documented causative pathogen of nosocomial bloodstream infection. The present study aimed to identify climatological variables that are associated with Bacillus-positive blood culture in Sapporo, Japan. All cases with Bacillus-positive blood cultures from January 2011 to December 2016 were retrospectively analysed. Climatological data from 2011 to 2016, including daily mean temperature and absolute humidity, were retrieved from the Japan Meteorological Agency. Employing a hazard-based statistical model to describe the non-homogeneous counting process in which temperature and absolute humidity act as explanatory variables, we computed all possible models with variable lengths of time lag. Akaike Information Criterion was computed to identify the best fitted model. High wavelet power at 12 months was identified for the period from 2013 onwards, which coincided with the time period in which sampling multiple sets of blood culture has been recommended. The temperature-only model with a lag of six days yielded a high sensitivity value (72.1%) and appeared to be the optimal model to predict Bacillus-positive blood culture with the highest area under the receiver operating characteristic curve value. Temperature was identified as a climatological driver of Bacillus-positive blood culture. Our statistical modelling exercise offers an important message for infection control practices to improve awareness among healthcare workers of the identified association and mechanically controlled in-room temperature.

scholarly journals An estimate for the source of coagulase-negative staphylococci in blood cultures

1987 ◽  
Vol 99 (2) ◽  
pp. 333-341 ◽  
Author(s):  
M. J. Haverkorn ◽  
M. J. Staal
Keyword(s):  
Blood Culture ◽  
Positive Blood Culture ◽  
Heart Surgery ◽  
Open Heart Surgery ◽  
Culture Technique ◽  
Blood Cultures ◽  
The Other ◽  
Open Heart ◽  
Coagulase Negative Staphylococci ◽  
Two Populations

SUMMARYAn estimate for the source of coagulase-negative staphylococci in blood cultures is presented and its use illustrated in two populations. The method estimates the probability that a positive blood culture is positive due to contamination and the probability of it being positive due to bacteraemia. The effect of changes in efficiency of the blood culture technique on these estimates is demonstrated. One of the illustrative populations consists of 537 sample pairs from 273 patients, taken after open-heart surgery in 1978–80. The other consists of 500 consecutive sample pairs taken in one of two hospitals in 1983–4.

scholarly journals Decreasing Blood Culture Contamination Rates Using A Specimen Diversion Device: A Quasi-Experimental Study

2020 ◽  
Vol 41 (S1) ◽  
pp. s468-s468
Author(s):  
Ahmed Babiker ◽  
Aditi Ramakrishnan ◽  
Jessica Howard-Anderson ◽  
Jill Holdsworh ◽  
Mini Jacob ◽  
...  
Keyword(s):  
Experimental Study ◽  
Blood Culture ◽  
Blood Cultures ◽  
Contamination Rate ◽  
Relative Reduction ◽  
Coagulase Negative Staphylococci ◽  
Total Blood ◽  
Level Change ◽  
Its Analysis ◽  
Quasi Experimental

Background: Blood culture contamination rates are frequently higher than the ≤3% standard in the emergency department (ED). Objective: We sought to determine whether the implementation of a blood diversion device that mechanically sequesters the initial aliquot of the blood culture sample decreased blood culture contamination rates. Methods: We performed a quasi-experimental study in two 500-bed hospitals. The blood-diversion device was implemented in the ED in hospital A, but not in hospital B, starting in January 2018. Preintervention data were collected over a 29-month baseline period, and postintervention data were collected for 20 months. Both hospitals provided ongoing feedback on contamination rates. Blood culture contamination was defined as presence of common skin microbiota (eg, coagulase-negative staphylococci) in only 1 of ≥2 blood culture sets collected within 24 hours. Preintervention and postintervention blood culture contamination rates were calculated based on total blood cultures collected and were compared within and between hospitals using the Wilcoxon rank-sum test. Changes in preintervention and postintervention total and ED contamination rates within hospitals were calculated as rate ratios (RRs) using interrupted time series (ITS) analysis with segmented Poisson regression. Results: Among 212,789 total blood cultures (hospital A, 70,005; hospital B, 142,784), 4,025 (1.8%) were contaminated. In hospital A, the intervention resulted in a decrease in overall median blood culture contamination rates (2.4% vs 1.4%; P < .001) and ED median blood culture contamination rates (4.7% vs 2.6%; P < .001), whereas in hospital B there was no significant change during the same period in overall (2.3% vs 2.0%) or ED (5.0% vs 5.0%) median blood culture contamination rates. In the ITS analysis, the intervention was associated with an immediate decrease in hospital A’s contamination rate by 21.3% (level change RR, 0.79; 95% CI, 0.63–0.98; P = .04) overall and 21.0% (level change RR, 0.79; 95% CI, 0.62–1.0; P =.06) in the ED. After the intervention, there was a continued decrease in hospital A’s overall (trend change RR, 0.95; 95% CI, 0.93–0.97; P < .001) and ED (trend RR, 0.94; 95% CI, 0.92–0.96; P < .001) blood culture contamination rates, but not in hospital B’s overall (trend change RR, 1.02; 95% CI, 1.00–1.02; P = .01) or ED (RR, 1.00; 95% CI, 0.99–1.02; P = .30) blood culture contamination rates during the same period. Conclusions: Implementation of the blood diversion device in the ED resulted in a >20% relative reduction from a baseline of 5% of ED blood culture contamination rates. Continued improvement after implementation suggests ongoing efforts to address the workflow and the culture of safety are needed to optimize the use of this device.Funding: NoneDisclosures: None

Distinguishing Sepsis From Blood Culture Contamination in Young Infants With Blood Cultures Growing Coagulase-Negative Staphylococci

PEDIATRICS ◽  
1990 ◽  
Vol 86 (2) ◽  
pp. 157-162
Author(s):  
Joseph W. St Geme ◽  
Louis M. Bell ◽  
Stephen Baumgart ◽  
Carl T. D'Angio ◽  
Mary Catherine Harris
Keyword(s):  
Blood Culture ◽  
Peripheral Blood ◽  
Clinical Information ◽  
Study Groups ◽  
Blood Cultures ◽  
High Risk Population ◽  
Coagulase Negative Staphylococci ◽  
Peripheral Blood Culture ◽  
Young Infants ◽  
Initial Culture

Coagulase-negative staphylococci represent the most common cause of serious nosocomial infection in many intensive care nurseries. However, these organisms are also common blood culture contaminants. To determine the value of quantitative blood cultures in distinguishing sepsis from culture contamination, we reviewed records of all infants in our nurseries who had peripheral blood isolates of coagulase-negative staphylococci during a 3-year period. Twenty-three episodes of sepsis were identified in 21 infants, and 10 infants had blood culture contamination. Colony counts from the initial peripheral blood culture were significantly different for the two study groups (P &lt; .001). In 9 of 23 episodes of sepsis, the initial peripheral blood culture grew &gt;100 colony-forming units (cfu) per mL. In the other 14 episodes, the initial culture yielded ≤50 cfu/mL. All 10 infants with culture contamination had colony counts of &lt;50 cfu/mL, and in 9 the initial peripheral blood culture grew &lt;20 cfu/mL. Infants with sepsis, including those with colony counts of ≤50 cfu/mL, were significantly more likely to have a central catheter or an abnormal hematologic value or both (P &lt; .05). Infants who lacked these clinical features were more likely to have contamination. We conclude that quantitative blood cultures in conjunction with specific clinical information may distinguish sepsis from culture contamination with coagluase-negative staphylococci in young infants. In addition, low colony-count growth should not be ignored as contamination in this high-risk population.

scholarly journals Antimicrobial Stewardship Standards and Patient Safety: A Case Study in Blood Culture Contamination

2021 ◽  
Vol 1 (S1) ◽  
pp. s36-s36
Author(s):  
Connie Schaefer
Keyword(s):  
Blood Culture ◽  
Healthcare System ◽  
Antimicrobial Stewardship ◽  
Standard Method ◽  
Broad Spectrum ◽  
Emergency Departments ◽  
Blood Cultures ◽  
Contamination Rate ◽  
Broad Spectrum Antibiotics ◽  
Contamination Events

Background: Blood culture is a crucial diagnostic tool for healthcare systems, but false-positive results drain clinical resources, imperil patients with an increased length of stay (and associated hospital-acquired infection risk), and undermine global health initiatives when broad-spectrum antibiotics are administered unnecessarily. Considering emerging technologies that mitigate human error factors, we questioned historically acceptable rates of blood culture contamination, which prompted a need to promote and trial these technologies further. In a 3-month trial, 3 emergency departments in a midwestern healthcare system utilized an initial specimen diversion device (ISDD) to draw blood cultures to bring their blood culture contamination rate (4.4% prior to intervention) below the 3% benchmark recommended by the Clinical & Laboratory Standards Institute. Methods: All emergency department nursing staff received operational training on the ISDD for blood culture sample acquisition. From June through August 2019, 1,847 blood cultures were drawn via the ISDD, and 862 were drawn via the standard method. Results: In total, 16 contamination events occurred when utilizing the ISDD (0.9%) and 37 contamination events occurred when utilizing the standard method (4.3%). ISDD utilization resulted in an 80% reduction in blood culture contamination from the rate of 4.4% rate held prior to intervention. Conclusions: A midwestern healthcare system experienced a dramatic reduction in blood culture contamination across 3 emergency departments while pilot testing an ISDD, conserving laboratory and therapeutic resources while minimizing patient exposure to unnecessary risks and procedures. If the results obtained here were sustained and the ISDD utilized for all blood culture draws, nearly 400 contamination events could be avoided annually in this system. Reducing unnecessary antibiotic use in this manner will lower rates of associated adverse events such as acute kidney injury and allergic reaction, which are possible topics for further investigation. The COVID-19 pandemic has recently highlighted both the importance of keeping hospital beds available and the rampant carelessness with which broad-spectrum antibiotics are administered (escalating the threat posed by multidrug-resistant organisms). As more ambitious healthcare benchmarks become attainable, promoting and adhering to higher standards for patient care will be critical to furthering an antimicrobial stewardship agenda and to reducing treatment inequity in the field.Funding: NoDisclosures: None

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