High positive predictive value of Gram stain on catheter-drawn blood samples for the diagnosis of catheter-related bloodstream infection in intensive care neonates

Prevalence of central venous catheter salvage in newborn with staphylococcal bloodstream infection

OBJECTIVES

to establish the prevalence of salvage of central venous catheters in newborns with bloodstream infection caused by coagulase-negative staphylococci.

METHODS

retrospective cross-sectional study with 136 newborns admitted to the Neonatal Intensive Care Unit between 2011 and 2017. The total of 143 infection events undergoing antibiotic therapy were evaluated.

RESULTS

among the 143 infection events, 39 catheters in which antibiotic therapy was used were saved and in 69 cases, the device was removed. Positive central blood culture and single lumen catheter were factors associated with salvage failure. The probability of salvage decreased with infections diagnosed from 15 days of using the catheter. Negative blood culture raised the chance of salvage by fourfold.

CONCLUSIONS

the use of antibiotic therapy in the treatment of infections resulted in a low prevalence of salvage of the central venous catheter. The probability of salvage was associated with variables of the device.

Healthcare-associated infections in high-risk neonates: Temporal trends in a national surveillance system

BACKGROUND

Increased survival of preterm neonates who require hospitalization at the Neonatal Intensive Care Unit has led to an increase in infections. This study aims to describe the temporal trend, risk factors, and outcome of healthcare-associated infections in a NICU of a high complexity hospital, with emphasis on the differences of incidence between bacterial and fungal infections.

METHODS

The study was carried out from January 2013 to December 2016, with daily follow-up of the newborns by the National Healthcare Safety Network.

RESULTS

The study included 881 newborns, of whom 214 had a bacterial infection, 19 had fungi infection, and 12 bacterial and fungal infections associated. The hospital infection rate was 12/1000 patient-days. SNAPPE>24, days of hospitalization and PICC days were independent risk factors for the development of fungal and bacterial infection, respectively, with statistical significance for bacterial and fungal infections. The mortality rate was 2.6 times higher in those who had fungal infection than in those who had a bacterial infection. The occurrence of invasive infections was higher in the years 2015 and 2016 and Gram-negative bacteria and yeasts were more frequent, impacting morbidity and mortality.

CONCLUSIONS

The use of invasive devices is a risk factor for the occurrence of HAI caused by bacteria and fungi. The frequency of deaths was higher in the group of neonates with fungal infection. These results point to the importance of constant epidemiological surveillance and measures of effective control of infections in NICU.

Development of a standardized Gram stain procedure for bacteria and inflammatory cells using an automated staining instrument

Gram stain is a subjective and poorly controlled test, and the resultant errors often perplex laboratory scientists. To reduce errors and make Gram stain a precisely controllable and meritorious test, a standardized Gram stain procedure for bacteria and inflammatory cells was developed using an automated staining instrument in this study. Freshly expectorated sputum specimens, used as the optimized targets, were smeared on slides by laboratory technicians, defining each slide loaded with uniform matrix and monolayer cell. And then, the staining and decolorizing time, as well as the stain and decolorant volume, were optimized as 15, 105, 1, and 25 s and 1.1, 1.4, 0.3, and 0.7 ml, respectively. Culture‐positive blood specimens and original purulent fluids were used for confirming the developed standardized Gram stain procedure. Distinct tinctures of bacteria and inflammatory cells adhered to slide uniformly in a monolayer were observed, and the obtained staining results of these samples were highly consistent with their cultured results. Furthermore, according to the staining results under different staining conditions, an updated molecular mechanism of Gram stain for bacteria and the probable staining mechanism for inflammatory cells were also proposed in this study.

Rectal and Naris Swabs: Practical and Informative Samples for Analyzing the Microbiota of Critically Ill Patients

Commensal microbiota are immunomodulatory, and their pathological perturbation can affect the risk and outcomes of infectious and inflammatory diseases. Consequently, the human microbiota is an emerging diagnostic and therapeutic target in critical illness. In this study, we compared four sample types-rectal, naris, and antecubital swabs and stool samples-for 16S rRNA gene microbiota sequencing in intensive care unit (ICU) patients. Stool samples were obtained in only 31% of daily attempts, while swabs were reliably obtained (≥97% of attempts). Swabs were compositionally distinct by anatomical site, and rectal swabs identified within-patient temporal trends in microbiota composition. Rectal swabs from ICU patients demonstrated differences from healthy stool similar to those observed in comparing stool samples from ICU patients to those from the same healthy controls. Rectal swabs are a useful complement to other sample types for analysis of the intestinal microbiota in critical illness, particularly when obtaining stool may not be feasible or practical.IMPORTANCE Perturbation of the microbiome has been correlated with various infectious and inflammatory diseases and is common in critically ill patients. Stool is typically used to sample the microbiota in human observational studies; however, it is often unavailable for collection from critically ill patients, reducing its utility as a sample type to study this population. Our research identified alternatives to stool for sampling the microbiota during critical illness. Rectal and naris swabs were practical alternatives for use in these patients, as they were observed to be more reliably obtained than stool, were suitable for culture-independent analysis, and successfully captured within- and between-patient microbiota differences.

Clinical usefulness of catheter-drawn blood samples and catheter tip cultures for the diagnosis of catheter-related bloodstream infections in neonatology: A systematic review

OBJECTIVES

Neonatal sepsis is the most frequent health care-associated infection in neonatal units. This study aimed to analyze articles on the clinical usefulness of catheter-drawn blood samples and catheter tip cultures for the diagnosis of intravascular catheter-related bloodstream infection (CRBSI) in neonates.

METHODS

A systematic search was performed for studies published from 1987-2017, without language restriction. Observational studies carried out in neonates with CRBSI diagnosed using catheter-drawn blood samples or catheter tip cultures were included.

RESULTS

A total of 412 articles were identified in the databases and 10 articles were included. The 7 studies that evaluated central venous catheter tip cultures and cultures of catheter fragments presented sensitivities ranging from 58.5%-100% and specificities ranging from 60%-95.7%. Three studies that evaluated catheter-drawn blood cultures, paired with peripheral blood cultures, reported sensitivity and specificity of 94% and 71% when evaluated for the differential time to positivity. When quantitative evaluation was performed, the sensitivity and specificity were 80% and 99.4%.

CONCLUSIONS

Most of the studies analyzed cultures from the central venous catheter tip and catheter fragments for the diagnosis of CRBSI in neonatal populations. The results of this review suggest that the analysis of the catheter-drawn blood samples and catheter tip cultures, paired with peripheral blood cultures, are efficient methods for the diagnosis of CRBSI in neonates.

Direct Gram staining and its various benefits in the diagnosis of bacterial infections

In the era of rapid development of molecular and other diagnostic methods, direct Gram staining (DGS) tends to remain in the background, although it can provide both microbiologists and clinicians numerous benefits. The aim of this review was to emphasize the importance of DGS for the diagnosis of many clinically important infections. A PubMed search was carried out using relevant keywords for articles published primarily since 2010. The DGS can provide early information for a timely diagnosis of infections, can reveal the causative agents of the infections even under suboptimal conditions of specimen collection, transport or identification methods, can detect the presence of rare/unusual pathogens, moreover, the method shows the specimen quality, by distinguishing between contamination and true infection, it can direct or change initial antibiotic treatment before the availability of culture results, can indicate the need of other methods for pathogen identification and, in some cases, can show the need for emergency attention such as urgent antibiotic therapy and surgical measures. Briefly, the DGS remains an easy, rapid, inexpensive and important method, which use should be encouraged in conditions of a standardized and controlled performance to avoid technical or interpretation errors.