Correlation of Neutrophil CD64 with Clinical Profile and Outcome of Sepsis Patients during Intensive Care Unit Stay

Introduction:

Neutrophil CD64 (nCD64) has been found to identify sepsis from nonseptic patients. It is also reported to be a predictor of survival and severity of sepsis. The goal of this study was to correlate serial nCD64 with Intensive Care Unit (ICU) outcome and severity of sepsis.

Materials and Methods:

A prospective observational study was conducted in 12-bedded critical care unit of a tertiary care center. Adult patients with sepsis were included in this study. Demographics, illness severity scores, clinical parameters, laboratory data, and 28-day outcome were recorded. Serial nCD64 analysis was done (on days 0, 4, and 8) in consecutive patients.

Results:

Fifty-one consecutive patients were included in the study. Median Acute Physiology and Chronic Health Evaluation II was 16 (12–20) and mean Sequential Organ Failure Assessment was 9 (8–10). Compared to survivors, nonsurvivors had higher nCD64 on day 8 (P = 0.001). nCD64 was higher in the septic shock group compared to sepsis group on days 0 and 8 (P < 0.05). Survivors showed improving trend of nCD64 over time while nonsurvivors did not. This trend was similar in the presence or absence of septic shock. nCD64 count was a good predictor of the septic shock on day 0 (area under the curve [AUC] = 0.747, P = 0.010) and moderate predictor at day 8 (AUC = 0.679, P = 0.028).

Conclusion:

Monitoring serial nCD64 during ICU stay may be helpful in determining the clinical course of septic patients.

Sending repeat cultures: is there a role in the management of bacteremic episodes? (SCRIBE study)

Background

In the management of bacteremia, positive repeat blood cultures (persistent bacteremia) are associated with increased mortality. However, blood cultures are costly and it is likely unnecessary to repeat them for many patients. We assessed predictors of persistent bacteremia that should prompt repeat blood cultures.

Methods

We conducted a retrospective cohort study of bacteremias at an academic hospital from April 2010 to June 2014. We examined variables associated with patients undergoing repeat blood cultures, and with repeat cultures being positive. A nested case control analysis was performed on a subset of patients with repeat cultures.

Results

Among 1801 index bacteremias, repeat cultures were drawn for 701 patients (38.9 %), and 118 persistent bacteremias (6.6 %) were detected. Endovascular source (adjusted odds ratio [aOR], 7.66; 95 % confidence interval [CI], 2.30-25.48), epidural source (aOR, 26.99; 95 % CI, 1.91-391.08), and Staphylococcus aureus bacteremia (aOR, 4.49; 95 % CI, 1.88-10.73) were independently associated with persistent bacteremia. Escherichia coli (5.1 %, P = 0.006), viridans group (1.7 %, P = 0.035) and β-hemolytic streptococci (0 %, P = 0.028) were associated with a lower likelihood of persistent bacteremia. Patients with persistent bacteremia were less likely to have achieved source control within 48 h of the index event (29.7 % vs 52.5 %, P < .001), but after variable reduction, source control was not retained in the final multivariable model.

Conclusions

Patients with S. aureus bacteremia or endovascular infection are at risk of persistent bacteremia. Achieving source control within 48 h of the index bacteremia may help clear the infection. Repeat cultures after 48 h are low yield for most Gram-negative and streptococcal bacteremias.

Epidemiological Evaluation of Blood Culture Patterns among Neonates Receiving Vancomycin

The objective of this study was to assess the frequency of blood culture (BC) collection among neonates who received vancomycin. Demographic, clinical, microbiologic, and pharmacy data were collected for 1275 neonates (postnatal age 0-27 days) who received vancomycin at an Intermountain Healthcare facility between 1/2006 and 9/2011. Neonates treated with vancomycin had a BC collected 94 % (n = 1198) of the time, of which 37 % (n = 448) grew one or more bacterial organisms (BC positive). Of these, 1 % (n = 5) grew methicillin-resistant Staphylococcus aureus (MRSA), 71 % (n = 320) grew coagulase-negative Staphylococci (CoNS), 9 % (n = 40) grew methicillin-sensitive Staphylococcus aureus (MSSA), and 22 % (n = 97) grew other bacterial species (total exceeds 100 % due to co-detection). In patients with negative BC or no BC, vancomycin therapy was extended beyond 72 h 52 % of the time. The median duration of vancomycin therapy for patients with a negative BC was 4 (IQR: 2-10) days. BCs were frequently obtained among neonates who received vancomycin. Vancomycin therapy beyond the conventional 'empiric' treatment window of 48-72 h was common without isolation of resistant gram-positive bacteria.

Impact of prior antibiotic use in culture-negative endocarditis: review of 86 cases from southern Pakistan

BACKGROUND

A large number of patients treated at our hospital for endocarditis have negative cultures. Taking into consideration the fact that many of these patients receive antibiotics prior to referral, we decided to study culture-negative endocarditis in Pakistan.

METHODS

The medical records of all patients admitted to the Aga Khan University Hospital, Pakistan, for the period from 1988 to 2001, with an underlying diagnosis of infective endocarditis (IE) and negative cultures, were reviewed.

RESULTS

Of the 159 patients diagnosed with IE by revised Duke criteria, 86 (54.1%) had persistent negative cultures. More than half of these patients (52%) had received antibiotics before being referred to our center. Patients with culture-negative endocarditis were less likely to be classified as definite endocarditis by revised Duke criteria (p<0.001, 95% CI 0.07-0.3) or to have large vegetations (p=0.021, 95% CI 0.05-0.5), and more likely to have a mitral valve prolapse (p=0.003, 95% CI 1.6-2.3). Definite endocarditis (p=0.042, 95% CI 1.02-7.4), heart failure (p=0.008, 95% CI 1.4-12.7), renal failure (p=0.017, 95% CI 1.16-40.7), embolism (p=0.019, 95% CI 1.2-38.8), and neurological complications (p=0.02, 95% CI 1.16-9.2) were associated with an increased mortality.

CONCLUSION

Culture-negative endocarditis is very common among patients with IE in Pakistan. The presentation, laboratory findings, and complications are similar to those for culture-positive endocarditis. It is postulated that previous antibiotic treatment is the most common cause of culture-negative endocarditis in our hospital.

Swedish guidelines for diagnosis and treatment of infective endocarditis

Swedish guidelines for diagnosis and treatment of infective endocarditis (IE) by consensus of experts are based on clinical experience and reports from the literature. Recommendations are evidence based. For diagnosis 3 blood cultures should be drawn; chest X-ray, electrocardiogram, and echocardiography preferably transoesophageal should be carried out. Blood cultures should be kept for 5 d and precede intravenous antibiotic therapy. In patients with native valves and suspicion of staphylococcal aetiology, cloxacillin and gentamicin should be given as empirical treatment. If non-staphylococcal etiology is most probable, penicillin G and gentamicin treatment should be started. In patients with prosthetic valves treatment with vancomycin, gentamicin and rifampicin is recommended. Patients with blood culture negative IE are recommended penicillin G (changed to cefuroxime in treatment failure) and gentamicin for native valve IE and vancomycin, gentamicin and rifampicin for prosthetic valve IE, respectively. Isolates of viridans group streptococci and enterococci should be subtyped and MIC should be determined for penicillin G and aminoglycosides. Antibiotic treatment should be chosen according to sensitivity pattern given 2-6 weeks intravenously. Cardiac valve surgery should be considered early, especially in patients with left-sided IE and/or prosthetic heart valves. Absolute indications for surgery are severe heart failure, paravalvular abscess, lack of response to antibiotic therapy, unstable prosthesis and multiple embolies. Follow-up echocardiography should be performed on clinical indications.

Laboratory testing in the intensive care unit

Laboratory testing is ubiquitous among hospitalized patients and is more common among patients in the intensive care unit (ICU). Despite its high cost and prevalence, there are few data to support the current practice of laboratory testing in most ICUs. Although testing offers considerable potential benefits, it is not without risk, including misleading results, iatrogenic anemia, and therapeutic actions of uncertain benefit. Laboratory testing should be conducted as part of a therapeutic approach to a clinical problem, mindful of pretest probability of disease, the performance of the selected test, and the relative benefits and risks of testing. Considering the indication for a particular test can lead to a more rational approach to laboratory testing and better use of available tests.

Characteristics of infective endocarditis in a developing country-clinical profile and outcome in 192 Indian patients, 1992–2001

Total 198 episodes of Duke "definite" infective endocarditis (IE) in 192 patients observed over last 10 years were studied [141 males and 51 females, mean age 27.6+/-12.7 years (range 4-68 years)]. Majorities of patients (76.5%) were below 40 years of age. Rheumatic heart disease (RHD) was the commonest underlying heart disease (present in 46.9% patients). Probable source of infection could be identified in only 16.6% episodes. None of our patient was intravenous drug abuser. Fever (90.0%), anemia (81.0%), clubbing (58.1%), splenomegaly (60.6%), changing/new murmur (22.7%) were the common clinical findings. Vegetations were present in 89.9% episodes. Blood cultures were positive in 134 (67.7%) episodes (streptococci in 23.2%, staphylococci in 19.7%, gram negative in 13.6%, enterococci in 8.1%, polymicrobial and fungal in 1.5% episodes each). Complications were cardiovascular [congestive heart failure (CHF) in 41.9%, atrioventricular block in 1.5%, cardiac temponade and acute myocardial infarction in 0.5% each), neurological in 16.6%, renal in 13.1% and embolisms in total 21.7% episodes. Total 182 (91.9%) episodes in 176 patients were managed completely [(medical in 140 (76.9%) and surgical in 42 (23.1%) episodes] while patients in remaining 16 (8.1%) episodes left against medical advises before completion of therapy. Total 21% patients (37 out of 176 completely treated patients) died during therapy (cause of deaths; CHF in 11, septicemia in 10, cerebral embolism in 7, post cardiac surgery in 5, ruptured cerebral mycotic aneurysm in 2, ventricular tachycardia in 2 patients). On stepwise logistic regression analysis; cardiac abscess and CHF were independent predictors of cardiac surgery. Similarly, CHF, renal failure and prosthetic valve dysfunction were independent predictors of mortality. To conclude, spectrum of IE in our country is different from the west, but quite similar as reported from developed countries about 40 years ago. IE in our country occurs in relatively younger population with RHD as the commonest underlying heart disease. Streptococci are still the commonest responsible microorganisms. Morbidity and mortality are still high. Early cardiac surgery, whenever indicated, helps in improving outcome of these patients.

Repeating blood cultures during hospital stay: practice pattern at a teaching hospital and a proposal for guidelines

Guidelines for blood culture (BC) address the appropriate frequency, number and volume, but no guidelines exist for repeating BCs. The pattern of repeated BCs was studied in all patients hospitalised in December 2001 to determine the extent of and reasons for repeating cultures. BC was repeated in 127 (31.6%) of 405 adults with an initial BC during the study period. All patients with available records (n = 96; 75.6%) were included. The average patient age was 62.2 +/- 15.9 years. In total, 295 BC sets (one to four BCs/set) were obtained, comprising 96 initial and 199 repeats (one to nine repeats/patient). Sixty-nine (34.7%) repeats were taken within 24 h, and 89 (44.7%) within 2-4 days. The most common reason (32.2%) was persistent fever. The result of repeated cultures was: no growth (83.4%), same pathogen (9.1%), new pathogen (2.5%) or contamination (5.0%). Thus, BC repeats accounted for one-third of all BCs handled in the laboratory, with little additional yield. Guidelines for repeating BCs may decrease unnecessary testing.

Surgical emergencies in the intravenous drug user

Numerous surgical complications arise from parenteral drug use. Some complications have severe sequelae and most prove to be a diagnostic challenge. It is likely that these problems will remain a significant burden on the health care system as a result of continued widespread drug abuse. EPs must always maintain vigilance when evaluating medical complaints in the IVDU.

Usefulness of cytokines interleukin-6 and interleukin-2R concentrations in diagnosing active infective endocarditis involving native valves

The most important diagnostic value in infective endocarditis (IE) is isolation of the causative microorganism. Because premature antibiotic treatment is commonly administered before the assessment of blood cultures, the percentages of isolated microorganisms has decreased significantly within the last decades. Therefore, additional criteria for the diagnosis of IE may be helpful. It was hypothesized that assessment of interleukin-6 (IL-6) and interleukin-2R (IL-2R) may provide new diagnostic criteria for inflammation in IE. IL-6 and IL-2R serum concentrations, white blood cell count (WBC), and C-reactive protein (CRP) were measured in the blood of 47 patients with IE at the time of diagnosis and during treatment. WBC and CRP were elevated in patients with IE at the time of diagnosis. Both parameters were higher (p <0.05) in patients with positive blood cultures when compared with negative cultures. The differences persisted during the first week of treatment (p <0.01). In contrast, IL-6 and IL-2R concentrations were elevated (p <0.001) independently of the status of blood cultures. Serum concentrations of IL-6 and IL-2R decreased continuously during antibiotic treatment. Assessment of IL-6 and IL-2R could thus provide new diagnostic criteria for inflammation in IE, and these interleukins could also be suitable for monitoring the course of inflammation during treatment.

Rapid serodiagnosis of gram-positive bacterial endocarditis

OBJECTIVES

To characterize a serological test for diagnosing endocarditis caused by Gram-positive cocci.

METHODS

We have developed an indirect enzyme-linked immunosorbent assay (ELISA) for the serological detection of Gram-positive infections. The test measures serum IgG directed towards lipid S, a recently identified exocellular glycolipid antigen which is related to lipoteichoic acid. We have previously shown the test to be of value in serodiagnosis of central venous catheter-associated sepsis and infection of orthopaedic prostheses caused by coagulase-negative staphylococci. We now describe the application of this test in endocarditis.

RESULTS

Serum IgG levels to lipid S were significantly elevated in 34 patients with Gram-positive bacterial endocarditis confirmed as 'definite' by the Duke criteria as compared to 50 control patients. The test had a sensitivity of 88% and a specificity of 88%.

CONCLUSIONS

The assay is independent of culture results or endocardial imaging, making it complementary to currently used investigations. It may therefore be possible to refine the current Duke criteria for diagnosing endocarditis. We describe an algorithm which incorporates lipid S serology into a positive diagnostic strategy.

Advances in medical and antibiotic management of infective endocarditis

Infective endocarditis remains a serious medical problem despite advancements in laboratory detection, echocardiographic techniques, and newer antibiotic agents. This article summarizes the microbial agents in infective endocarditis, in addition to developments in medical and antibiotic management.

Evaluation of new clinical criteria for the diagnosis of infective endocarditis

PURPOSE

The clinical diagnosis of infective endocarditis (IE) can be difficult. A new diagnostic schema for IE (the Duke criteria) has been proposed, utilizing clinical, microbiologic, and echocardiographic data. We evaluated the Duke criteria in a cohort of prospectively enrolled patients suspected of having IE and compared the diagnostic efficiency of these criteria with the previously published criteria of von Reyn.

PATIENTS

Sixty-three febrile patients with suspected IE at a non-referral, municipal hospital were evaluated. All patients had the following parameters defined: the presence and nature of underlying heart disease; recent abuse of intravenous drugs; peripheral stigmata of IE; blood culture results; findings on two-dimensional transthoracic and transesophageal echocardiography (TTE, TEE); and the results of open heart surgery.

RESULTS

Twelve of 63 patients underwent open heart surgery, at which time IE was pathologically confirmed in 10 patients and excluded in 2 patients. All 10 patients with pathologically confirmed IE were classified as "clinically definite" by Duke criteria, whereas 5 of 10 were rejected by von Reyn criteria (p < 0.05). Among the remaining 51 patients suspected of IE and evaluated by both von Reyn and Duke clinical criteria, significantly more cases were classified as "definite" IE by Duke criteria than by von Reyn criteria (p < 10(-5)). Similarly, significantly fewer cases were rejected as IE by the Duke criteria as compared with the von Reyn criteria (p < 10(-6). Duke criteria were also significantly better at diagnosing IE than von Reyn criteria in the following clinical settings: suspected right-sided IE (p < 0.01); suspected left-sided IE (p = 0.014); suspected culture-negative IE (p < 10(-2); and IE complicating Staphylococcus aureus or viridans streptococcal bacteremias (p < 10(-5); p < 0.05, respectively). Among 30 cases defined as clinically definite by the Duke criteria, the presence of blood culture positivity and echocardiographically defined vegetations was important in this classification of 77% and 57% of cases, respectively. Among the 17 patients in the clinically definite category with vegetative endocarditis observed by echocardiography, 7 (41%) had vegetations defined only by TEE.

CONCLUSION

The Duke criteria are superior to the von Reyn criteria for the clinical diagnosis of IE, predominantly reflecting use of two-dimensional echocardiographic demonstration of valvular vegetations in the Duke schema.