Epidemiology and Clinical Significance of Blood Cultures Positive for Coagulase-Negative Staphylococcus

1985 ◽  
Vol 6 (12) ◽  
pp. 479-486 ◽  
Author(s):  
Louis V. Kirchhoff ◽  
John N. Sheagren
Keyword(s):  
Blood Culture ◽  
Medical Center ◽  
Antibiotic Sensitivity ◽  
Blood Cultures ◽  
Coagulase Negative Staphylococcus ◽  
Coagulase Negative Staphylococci ◽  
Prosthetic Valves ◽  
Short Period ◽  
True Blood ◽  
Intravascular Devices

AbstractCoagulase-negative staphylococci are frequently isolated from blood cultures. As these organisms may occasionally cause serious disease, differentiating bacteremia from contamination is very important but often difficult. Over a 26-month period, of 29,542 blood cultures processed at the University of Michigan Medical Center, 2,875 (9.7%) were positive, and of those, 694 (from 527 patients) grew coagulase-negative staphylococci. Isolates from the 439 patients with only one blood culture positive for coagulase-negative staphy-lococci and those from the 18 patients with two positive cultures 10 days or more apart were deemed contaminants. Review of the records of the remaining 70 patients with multiple isolates indicated that 33 had had an episode of true bacteremia, 29 (87.9%) of which were associated with intravascular catheters or prosthetic valves. Overall, 85% of all coagulase-negative staphylococci isolated during the study period were judged to be contaminants. Seventy-one percent of the blood cultures drawn during the episodes of bacteremia were positive for coagulase-negative staphylococci as opposed to only 34% in the patients with contaminated cultures (p < 0.01). Moreover, coagulase-negative staphylococci grew in both aerobic and anaerobic bottles in 85% of blood culture sets drawn during episodes of bacteremia, but in only 30% of the cultures thought to be contaminated (p < 0.001). Growth of coagulase-negative staphylococci in less than 48 hours was also significantly associated with bacteremia (p < 0.01). Antibiotic sensitivity patterns were not useful in differentiating bacteremia from contamination. Thus, clinicians should consider coagulase-negative staphylococci as true blood pathogens in patients with intravascular devices who have a high proportion of blood cultures positive for this organism over a short period of time, and whose cultures became positive in less than 48 hours, with a high percent positive in both bottles. Microbiology laboratories can conserve considerable resources by limiting sensitivity studies to isolates from such patients.

scholarly journals Five-year evaluation of the antimicrobial susceptibility patterns of bacteria causing bloodstream infections in Iran

2011 ◽  
Vol 6 (02) ◽  
pp. 120-125 ◽  
Author(s):  
Babak Pourakbari ◽  
Alireza Sadr ◽  
Mohammad Taghi Haghi Ashtiani ◽  
Setareh Mamishi ◽  
Mahdi Dehghani ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Blood Culture ◽  
Infection Control ◽  
Medical Center ◽  
Pediatric Population ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Coagulase Negative Staphylococci ◽  
Antimicrobial Drug Resistance ◽  
Oxacillin Resistance

Introduction: Bloodstream infections (BSI) are a serious cause of morbidity and mortality worldwide. Emerging antimicrobial drug resistance among bacterial pathogens causing BSI can limit therapeutic options and complicate patient management. Methodology: To encourage the prudent use of appropriate antibiotics in our pediatric population at Children's Medical Center Hospital, Tehran, Iran, we studied the frequency and antibiogram patterns of blood culture isolates from January 2001 to December 2005. Results: Of 25,223 blood cultures examined, 2,581 (10.23 %) were positive for bacterial growth. The frequency of Gram-positive bacteria isolated was 47.6% (1228 of 2581) and that for Gram-negatives was 52.4% (1353 of 2581). The rates of methicillin (oxacillin) resistance in Staphylococcus aureus and coagulase-negative staphylococci (CoNS) were 79% and 89%, respectively. About 45% of Streptococcus pneumoniae were resistant to trimethoprim-sulfamethoxazole and approximately 66% to penicillin. Among the Gram-negative isolates, Pseudomonas aeruginosa was most frequently isolated, representing 943 (36.7%) over five years. This possibly represents an unrecognized hospital outbreak or contamination of blood culture bottles or other products such as skin disinfectants. Additionally, this pathogen showed extremely high rates of antimicrobial resistance. There were notable differences in frequency of the five most common microorganisms isolated from blood cultures, which can help set priorities for focused infection control efforts. Conclusions: Our findings underscore the need to monitor blood culture isolates and their antimicrobial resistance patterns to observe resistance trends that would influence appropriate empiric treatment and infection control strategies for bacteremic children.  

Quality Improvement Project Demonstrate that Prolonged Pre-Analytical Time Does Not Lead to False Negative Blood Cultures

2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S140-S140
Author(s):  
E Abada ◽  
M Y Khan ◽  
N Yerrapotu ◽  
V Pardeshi ◽  
F Zaiem ◽  
...  
Keyword(s):  
Blood Culture ◽  
Medical Center ◽  
False Negative ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Coagulase Negative Staphylococcus ◽  
Blood Collection ◽  
Improvement Project ◽  
Negative Culture ◽  
Analytical Time

Abstract Introduction/Objective Bacterial infection is a significant cause of morbidity and mortality. Prompt identification of microorganisms and their susceptibilities to antimicrobial therapies is critical in the management of patients with bloodstream infections. Blood cultures are collected in paired aerobic and anaerobic bottles. However, transport delays might allow some organisms to grow extensively prior to incubation in the blood culture instruments, leading to false-negative culture results. The Detroit Medical Center utilizes the BD Bactec™ instruments for blood culture incubation and the Verigene DNA-based molecular assay for the identification of bacteria and major resistance genes. It has a core microbiology lab that serves 6 hospitals, however, 2 of the hospitals are remotely located. The aim of this project was to determine if transportation delays led to significant false-negative culture results. If significant false negativity occurred, additional Bactec™ instruments would need to be purchased. Methods For one month, we tracked the collection of blood cultures to incubation time at one of the remote hospitals. All blood cultures that remain negative after 164 hours of incubation are routinely discarded. However, in this case, they were subcultured to a Petri plate containing chocolate agar for 30 days. Any organisms that grew were identified by standard lab techniques. Results Of the 547 negative culture bottles that were subcultured for possible false-negative results, only 3 (0.5%) bottles grew bacteria. All three were isolated from different patients. The mean time from blood collection to incubation in the instrument was 4-8 hours. The isolates either met criteria for contaminated cultures, or they grew the same pathogen that had previously been identified in the paired bottle from the same culture. The organisms isolated include coagulase negative Staphylococcus species, Staphylococcus pettenkoferi, and Pseudomonas aeruginosa. No unexpected pathogenic organisms were detected. Conclusion Our results demonstrate that prolonged pre-analytical time does not lead to false-negative blood culture results. The patients’ diagnoses were not changed, therefore, the purchase of additional blood culture instruments was not necessary. However, transportation time from the patient floors to the main microbiology lab needs to be improved to meet the recommended 2 hours pre-analytical time.

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 Molecular epidemiology of catheter-related bloodstream infections caused by coagulase-negative staphylococci in haematological patients with neutropenia

2004 ◽  
Vol 132 (5) ◽  
pp. 921-925 ◽  
Author(s):  
M. MÜLLER-PREMRU ◽  
P. ČERNELČ
Keyword(s):  
Blood Culture ◽  
Staphylococcus Epidermidis ◽  
Clinical Signs ◽  
Bloodstream Infections ◽  
Venous Catheter ◽  
Blood Cultures ◽  
Peripheral Vein ◽  
Central Venous ◽  
Coagulase Negative Staphylococci ◽  
Haematological Patients

Catheter-related bloodstream infection (CRBSI) caused by coagulase-negative staphylococci (CNS) is common in haematological patients with febrile neutropenia. As the clinical signs of CRBSI are usually scarce and it is difficult to differentiate from blood culture contamination, we tried to confirm CRBSI by molecular typing of CNS isolated from paired blood cultures (one from a peripheral vein and another from the central venous catheter hub). Blood cultures were positive in 59 (36%) out of 163 patients. CNS were isolated in 24 (40%) patients; in 14 from paired blood cultures (28 isolates) and in 10 from a single blood culture. CNS from paired blood cultures were identified as Staphylococcus epidermidis. Antimicrobial susceptibility was determined and bacteria were typed by pulsed-field gel electrophoresis (PFGE) of bacterial genomic DNA. In 13 patients, the antibiotic susceptibility of isolates was identical. The PFGE patterns from paired blood cultures were identical or closely related in 10 patients, thus confirming the presence of CRBSI. In the remaining four patients they were unrelated, and suggested a mixed infection or contamination. Since CNS isolates from three patients had identical PFGE patterns, they were probably nosocomially spread amongst them.

Increased Antimicrobial Resistance of Pathogenic Coagulase-Negative Staphylococci From Blood Cultures (1961–1981)

1984 ◽  
Vol 5 (3) ◽  
pp. 142-143 ◽  
Author(s):  
D.J. Flournoy
Keyword(s):  
Staphylococcus Aureus ◽  
Blood Culture ◽  
Prosthetic Heart Valve ◽  
Bacterial Endocarditis ◽  
Blood Cultures ◽  
Coagulase Negative Staphylococci ◽  
Difficult Decision ◽  
Antimicrobial Susceptibilities ◽  
Cons Isolate ◽  
Intravenous Catheters

Coagulase-negative staphylococci (CONS) have only recently gained notoriety as pathogens. Several reports have established their pathogenicity in bacterial endocarditis, prosthetic heart valve endocarditis, intraventricular shunts for treatment of hydrocephalus and intravenous catheters. One difficult decision for physicians is determining whether a particular CONS isolate is pathogenic or contaminant. The differentiation of pathogenic and contaminant CONS has recently been noted, but further studies are needed to aid in this differentiation. Data on antimicrobial susceptibilities of positive blood culture isolates were recently compiled at this institution. This report compares antimicrobial susceptibilities of pathogenic and contaminant CONS and Staphylococcus aureus blood culture isolates from 1961-1981 at this institution.

Rate of positive blood cultures after 3 days of empiric antibiotics in pediatric cancer

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 9535-9535
Author(s):  
B. Kanathezhath ◽  
J. Feusner
Keyword(s):  
Blood Culture ◽  
Pediatric Oncology ◽  
Broad Spectrum ◽  
Signs And Symptoms ◽  
Blood Cultures ◽  
Coagulase Negative Staphylococcus ◽  
Cell Transplant ◽  
Hematopoietic Stem ◽  
Broad Spectrum Antibiotics ◽  
Related Mortality

9535 Background: Infections continue to be a major cause of morbidity and mortality in pediatric oncology patients (pts) with febrile neutropenia (FN). The proportion of such pts who have bacteremia documented after 72 hours (hrs) of broad-spectrum antibiotics, in the absence of local or systemic signs of infection, has not been previously reported. Methods: We conducted a retrospective analysis of all FN oncology pts admitted to our hospital during the period of August 1999 to October 2006. Blood cultures (BCs) from pts who were persistently febrile more than 3 days after initiation of empiric broad-spectrum antibiotics (ceftazidime and tobramycin) were analyzed. Medical records of pts with positive late blood cultures (LBCs) after 72 hrs were reviewed for onset of new signs and symptoms of infection. Hematopoietic stem cell transplant and HIV pts were excluded. Results: Ninety-seven episodes of persistent fever occurred in 71 FN pts. The total number of positive BCs in the first 72 hours was 24 (33.8%). Three (4.2%) of the persistently febrile pts had positive LBC. Of these 3 pts, one had preceding new signs and symptoms. Another had a probable contaminant (only 1 positive BC for coagulase-negative staphylococcus). Only one pt (1.4%) had positive LBC without any new local or systemic signs of infection. The observed frequency of positive LBC was 4.2% for pts and 0.8% (3/391) for total cultures obtained after 72 hours. There were no changes made in the antibiotic regimen of pts with positive LBC and none of them suffered from sepsis related mortality. Conclusions: This is the first report of late blood culture results in FN pediatric oncology pts. The practice of obtaining daily blood culture in such pts who are stable after 72 hrs of broad- spectrum antibiotics has a low yield (<5%), and even lower (<2%) if pts with new signs or symptoms at the LBC are excluded. This observation, if confirmed by larger studies from other centers, could lead to a more efficient, risk based strategy for following these pts. No significant financial relationships to disclose.

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.

Antibody Coated Bacteria in Otitis Media with Effusions

1980 ◽  
Vol 89 (3_suppl) ◽  
pp. 104-109 ◽  
Author(s):  
J. M. Bernstein ◽  
D. Myers ◽  
R. Nisengard ◽  
D. Kosinski ◽  
K. Wicher
Keyword(s):  
Otitis Media ◽  
Middle Ear ◽  
Otitis Media With Effusion ◽  
Antibiotic Sensitivity ◽  
Coagulase Negative Staphylococcus ◽  
Antibody Activity ◽  
Biochemical Tests ◽  
Coagulase Negative Staphylococci ◽  
Corynebacterium Species ◽  
External Canal

The significance of bacterial isolates of coagulase negative Staphylococcus epidermidis and Corynebacterium species in middle ear fluids remains controversial. This study was undertaken to evaluate the possible role of these organisms in different effusions. Cultures were obtained from the external cartilaginous ear, bony canal, tympanic membrane, middle ear fluids, tonsils and nasopharynx of 93 patients at the time of myringotomy for otitis media with effusion. Isolates of coagulase negative staphylococci from the middle ear, external ear and posterior aural skin were evaluated in regard to antibiotic sensitivity, biochemical tests and phage typing. Furthermore, in another series of patients in whom these organisms were isolated, specific antibody activity in both middle ear washings and corresponding sera were measured, using the technique of indirect immunofluorescence. The results suggest that the isolates from the middle ear and ear canal are not always identical. There is some evidence that specific IgM and IgG as well as IgA responses to these organisms are present in middle ear washings and not in corresponding serum. These results suggest that coagulase negative Staphylococcus and Corynebacterium species in middle ear effusions may not be contaminants from the external canal and that a local immune response may be produced by these organisms. Whether or not these organisms represent etiologic agents responsible for otitis media with effusion cannot be ascertained from this data. One very interesting point is the presence of IgE coating of organisms in some effusions.

Multidrug resistant coagulase-negative Staphylococcus spp. isolated from cases of chronic rhinosinusitis in humans. Study from Poland

2021 ◽  
Keyword(s):  
Chronic Rhinosinusitis ◽  
Pathogenic Bacteria ◽  
Medical Center ◽  
Multidrug Resistant ◽  
Coagulase Negative Staphylococcus ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant ◽  
Resistant Strains ◽  
Ethmoid Sinuses ◽  
Staphylococcus Spp

Abstract For many years, coagulase-negative staphylococci (CoNS) have been considered non-pathogenic bacteria. However, recently, CoNS are becoming more common bacteriological factors isolated from cases of chronic rhinosinusitis in humans. Moreover, most of them represent the multidrug-resistant or/and methicillin-resistant profile, which significantly increases the therapeutic difficulties. The aim of the study was to characterize profile of resistant coagulase-negative staphylococci isolated from cases of chronic rhinosinusitis in patients treated in a Medical Center in Warsaw in 2015–2016. The study material was derived from patients with diagnosed chronic rhinosinusitis treated at the MML Medical Center in Warsaw. The material was obtained intraoperatively from maxillary, frontal, and ethmoid sinuses. In total, 1,044 strains were isolated from the studied material. Coagulase-negative staphylococci were predominant, with the largest share of Staphylococcus epidermidis. Isolated CoNS were mainly resistant to macrolide, lincosamide, and tetracycline. Among the S. epidermidis strains, we also showed 35.6% of MDR and 34.7% of methicillin-resistant strains. The same values for other non-epidermidis species were 31.5% and 18.5%, respectively and the percentage of strains with MAR >0.2 was greater in S. epidermidis (32.6%) than S. non-epidermidis (23.9%). Although the percentage of strains resistant to tigecycline, glycopeptides, rifampicin and oxazolidinones was very small (2.3%, 1.9%, 1.4% and 0.7% respectively), single strains were reported in both groups. The study has shown a high proportion of MDR and methicillin-resistant CoNS strains, which indicates a large share of drug-resistant microorganisms in the process of persistence of chronic rhinosinusitis; therefore, isolation of this group of microorganisms from clinical cases using aseptic techniques should not be neglected.

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