Comparison of efficacy and safety between daptomycin plus β-lactam and daptomycin monotherapy for bloodstream infections due to gram-positive cocci: A systematic review and meta-analysis

Objectives

We performed a comprehensive systematic review and meta-analysis to evaluate the clinical or microbiological outcomes and safety of a combination of daptomycin (DAP) and β-lactams compared to DAP monotherapy in patients with blood stream infection (BSI) due to gram-positive cocci (GPC).

Methods

We searched Scopus, PubMed, EMBASE, CINAHL, and Ityuushi databases up to January 30, 2023. Outcomes included all-cause mortality, clinical failure, and creatine phosphokinase (CPK) elevation.

Results

Six cohorts or case-control studies fulfilled the inclusion criteria and were included in the final meta-analysis. Combination therapy of DAP and β-lactams significantly reduced the mortality and clinical failure rate for all BSI due to GPC compared with the DAP monotherapy (mortality, odds ratio [OR] = 0.63, 95 % confidence interval [CI] = 0.41-0.98; clinical failure, OR = 0.42, 95 % CI = 0.22-0.81). In contrast, no significant difference was noted in the incidence of CPK elevation between the two groups (OR = 0.85, 95 % CI = 0.39-1.84).

Conclusion

Altogether, combination therapy of DAP and β-lactams can improve the prognosis for patients with BSI due to GPC compared with DAP alone. Therefore, it should be considered as an option for the empirical treatment of BSI caused by GPC.

Predicting community acquired bloodstream infection in infants using full blood count parameters and C-reactive protein; a machine learning study

Early recognition of bloodstream infection (BSI) in infants can be difficult, as symptoms may be non-specific, and culture can take up to 48 h. As a result, many infants receive unneeded antibiotic treatment while awaiting the culture results. In this study, we aimed to develop a model that can reliably identify infants who do not have positive blood cultures (and, by extension, BSI) based on the full blood count (FBC) and C-reactive protein (CRP) values. Several models (i.e. multivariable logistic regression, linear discriminant analysis, K nearest neighbors, support vector machine, random forest model and decision tree) were trained using FBC and CRP values of 2693 infants aged 7 to 60 days with suspected BSI between 2005 and 2022 in a tertiary paediatric hospital in Dublin, Ireland. All models tested showed similar sensitivities (range 47% - 62%) and specificities (range 85%-95%). A trained decision tree and random forest model were applied to the full dataset and to a dataset containing infants with suspected BSI in 2023 and showed good segregation of a low-risk and high-risk group. Negative predictive values for these two models were high for the full dataset (> 99%) and for the 2023 dataset (> 97%), while positive predictive values were low in both dataset (4%-20%).   Conclusion: We identified several models that can predict positive blood cultures in infants with suspected BSI aged 7 to 60 days. Application of these models could prevent administration of antimicrobial treatment and burdensome diagnostics in infants who do not need them. What is Known: • Bloodstream infection (BSI) in infants cause non-specific symptoms and may be difficult to diagnose. • Results of blood cultures can take up to 48 hours. What is New: • Machine learning models can contribute to clinical decision making on BSI in infants while blood culture results are not yet known.

[Pyogenic spondylitis after Corynebacterium striatum blood stream infection following allogeneic hematopoietic stem cell transplantation for malignant lymphoma]

Patient 1 was a 70-year-old woman with refractory diffuse large B-cell lymphoma who received allogeneic peripheral blood stem cell transplantation from an HLA-haploidentical related donor. Upper back pain appeared on day63, and Th8-Th9 pyogenic spondylitis was diagnosed based on magnetic resonance imaging (MRI). Blood culture on day14 identified Corynebacterium striatum as the causative bacteria of blood stream infection (BSI). The pyogenic spondylitis resolved after treatment with daptomycin for 2 months. Patient 2 was a 65-year-old man with relapsed angioimmunoblastic T-cell lymphoma who received bone marrow transplantation from an HLA-DR single-antigen-mismatched unrelated donor. Lower back pain appeared on day30, and L4-L5 pyogenic spondylitis was diagnosed based on MRI. Blood culture was negative. Daptomycin and clindamycin were selected for treatment based on the drug susceptibility of bacteria that had caused pre-engraftment BSI (Escherichia coli on day3 and Corynebacterium striatum on day9), and the pyogenic spondylitis resolved after 6 months of this treatment. Pyogenic spondylitis should be considered in the differential diagnosis of back pain accompanied by BSI before engraftment in allogeneic hematopoietic stem cell transplant recipients.

Dissecting bloodstream infections in febrile neutropenic patients with hematological malignancies, a decade-long single center retrospective observational study (2009-2019)

BACKGROUND

The use of ill-suited antibiotics is a significant risk factor behind the increase in the mortality, morbidity, and economic burden for patients who are under treatment for hematological malignancy (HM) and bloodstream infections (BSI). Such unfitting treatment choices intensify the evolution of resistant variants which is a public health concern due to possible healthcare-associated infection spread to the general population. Hence, this study aims to evaluate antibiograms of patients with BSI and risk factors associated with septicemia.

METHODS

A total of 1166 febrile neutropenia episodes (FNE) among 513 patients with HM from the National Center for Cancer Care and Research (NCCCR), Qatar, during 2009-2019 were used for this study. The socio-demographic, clinical, microbial, and anti-microbial data retrieved from the patient's health records were used.

RESULTS

We analyzed the sensitivity of gram-negative and gram-positive bacilli reported in HM-FN-BSI patients. Out of the total 512 microorganisms isolated, 416 (81%) were gram-negative bacteria (GNB), 76 (15%) were gram-positive bacteria (GPB) and 20 (4%) were fungi. Furthermore, in 416 GNB, 298 (71.6%) were Enterobacteriaceae sp. among which 121 (41%) were ESBL (Extended Spectrum Beta-Lactamase) resistant to Cephalosporine third generation and Piperacillin-Tazobactam, 54 (18%) were Carbapenem-resistant or multidrug-resistant organism (MDRO). It's noteworthy that the predominant infectious agents in our hospital include E. coli, Klebsiella species, and P. aeruginosa. Throughout the study period, the mortality rate due to BSI was 23%. Risk factors that show a significant correlation with death are age, disease status, mono or polymicrobial BSI and septic shock.

CONCLUSION

Decision pertaining to the usage of antimicrobials for HM-FN-BSI patients is a critical task that relies on the latest pattern of prevalence, treatment resistance, and clinical outcomes. Analysis of the antibiogram of HM-FN-BSI patients in Qatar calls for a reconsideration of currently followed empirical antibiotic therapy towards better infection control and antimicrobial stewardship.

Rapid development of cefiderocol resistance in a carbapenem-resistant Pseudomonas aeruginosa isolate associated with mutations in the pyoverdine biosynthesis pathway

Here we report the in vivo development of cefiderocol resistance within 11 days after therapy initiation in a critically ill patient with bloodstream infection, infection of peri-anal fistula, and pneumonia caused by a VIM-2 harbouring, carbapenem-resistant Pseudomonas aeruginosa. Compared to a cefiderocol-naïve P. aeruginosa blood culture isolate, agar diffusion susceptibility testing found a reduced cefiderocol inhibition zone diameter in a P. aeruginosa recovered from peri-anal abscess tissue cultures after initiation of cefiderocol therapy. Subsequent whole-genome sequencing suggested that both isolates were of clonal origin. Comparison of genomes found an accumulation of missense mutations within pvdP, pvdE, pvdJ, and pvdD (i.e. genes associated with biosynthesis of pyoverdine), the main siderophore produced by P. aeruginosa. Quantification of pyoverdine production under iron-depleted conditions showed a significantly (P = 0.0003) higher pyoverdine production by the cefiderocol-resistant isolate. While pyoverdine quantity alone appears not to be decisive for cefiderocol resistance, the reported case highlights the potentially rapid emergence of cefiderocol resistance in P. aeruginosa and points towards a potential involvement of iron up-take systems in this process.

Candida auris Blood stream infection- a descriptive study from Qatar

BACKGROUND

Candida auris is an emerging yeast pathogen that can cause invasive infections, particularly candidemia, in healthcare settings. Candida auris is characterized by resistance to multiple classes of antifungal drugs and high mortality.

OBJECTIVE

To describe the risk factors, clinical characteristics, antifungal susceptibility pattern and outcomes of Candida auris blood stream infection.

METHODS

We conducted a retrospective review of electronic medical records of C. auris fungemia cases in the facilities under Hamad Medical corporation, Qatar from 1/11/2018 to 31/7/2021. Demographic data, risk factors, antibiogram and 30-day outcome are described.

RESULTS

We identified 36 patients with C. auris fungemia. Most of the patients were in intensive care unit following severe COVID-19 pneumonia and had received steroids and broad-spectrum antibiotics. Most cases were central line related. Over 90% of isolates were non-susceptible to fluconazole, while amphotericin B resistance reached 85%. Factors associated with high mortality included initial SOFA score of 9 or above and absence of source control.

CONCLUSION

Our study reveals a concerning 41.6% mortality rate within 30 days of C. auris candidemia. Furthermore, the prevalence of amphotericin B resistance in Qatar exceeds what has been reported in the literature necessitating further exploration. Echinocandins retains nearly 100% susceptibility and should be prioritized as the treatment of choice. These findings emphasize the need for vigilant monitoring and appropriate management strategies to combat C. auris infections and improve patient outcomes.

Difficult-to-treat resistant gram-negative blood stream infections - the beginning of a superbug era - a prospective observational study

INTRODUCTION

Carbapenem resistant gram-negative bacterial infections are a growing concern worldwide. However, India is already in the era of a shortage of effective antibiotics for the management of these infections. Moreover, Difficult-to-Treat Resistance (DTR) gram-negative infections, which are not much studied, further complicate the scenario. This study emphasized the incidence and outcomes of DTR infections.

METHODOLOGY

This is a single-center prospective observational study. The study included hospitalised patients aged ≥18 years with gram-negative bacterial bloodstream infections (GNBSI). Blood cultures with the growth of contaminants and/or single positive culture taken from the femoral site were excluded. Incidences of DTR infections and outcomes in the form of 30-day mortality were analysed.

RESULTS

Two hundred forty patients with GNBSI episodes were recorded. The Incidence of DTR GNBSI was 37.9% (91/240). Multivariate analysis found that Hospital-acquired infections, ICU admission and mechanical ventilation were independent risk factors for DTR GNBSI. The most common DTR GNB isolates were Klebsiella pneumoniae (31/49, 63.3%) and Acinetobacter baumannii (26/52, 50%). The adjusted relative risk of mortality was remarkably high in DTR GNBSI (aRR 3.9; 95% CI 1.9-7.9) as compared to CR+/DTR- GNBSI (aRR 0.3; 95% CI 0.1-1.0) and ESCR/CS GNBSI (aRR 1.1; 95% CI 0.5-2.4).

CONCLUSION

DTR GNB infections are growing concern in India and this need to be evaluated in multicentric studies. Moreover, DTR GNBSI was associated with significantly higher mortality and there is need of further empowerment of antibiotic stewardship practices.

Blood cultures with one venipuncture instead of two: a prospective clinical comparative single-center study including patients in the ICU, haematology, and infectious diseases departments

OBJECTIVES

Blood culture is a key method for diagnosing bloodstream infections. In this prospective study, we aimed to investigate whether blood cultures collected with the one-puncture method results in fewer contaminants, i.e. microorganisms from the skin or the environment, and the same detection of relevant pathogens compared to the two-puncture method. Further, we aimed to investigate if the time to blood culture positivity could be useful in evaluating contaminants.

METHODS

Patients planned for blood cultures were asked to participate in the study. From each recruited patient, six blood culture bottles were drawn, bottles 1-4 from the first venipuncture and bottles 5-6 from the second venipuncture. Within each patient, bottles 1-4 were compared to bottles 1, 2, 5, and 6 for contaminants and relevant pathogens. A sub-analysis was conducted on patients admitted to the ICU and those in the haematology department. We also assessed time-to-positivity for coagulase-negative staphylococci.

RESULTS

In the final analysis, 337 episodes from 312 patients were included. Relevant pathogens were identified in 62/337 (18.4%) episodes in both methods. Contaminants were detected in 12 (3.6%) and 19 episodes (5.6%) using the one-puncture and two-puncture method (p = .039), respectively. Corresponding results were observed in the sub-analysis. Notably, relevant coagulase-negative staphylococci demonstrated a shorter time-to-positivity compared to contaminant coagulase-negative staphylococci.

CONCLUSION

Blood cultures obtained using the one-puncture method resulted in significantly fewer contaminants and detected relevant pathogens equally to the two-puncture method. Time-to-positivity may be a useful additive indicator for predicting coagulase-negative staphylococci contamination in blood cultures.

Clinical features of febrile neutropenia and bloodstream infection in autologous hematopoietic cell transplantation: Comparison to those in intensive chemotherapy for acute myeloid leukemia

BACKGROUND

In autologous hematopoietic cell transplantation (HCT), myelosuppression and mucosal damage are more severe than those in conventional chemotherapy because of high-dose chemotherapy, but the duration of neutropenia is shorter due to stem cell rescue.

METHODS

We retrospectively evaluated febrile neutropenia (FN) and bloodstream infection (BSI) in 208 patients who underwent their first autologous HCT at our institution between 2007 and 2019. They were compared to those in patients who underwent intensive chemotherapy for acute myeloid leukemia (AML) (130 induction/salvage and 191 consolidation).

RESULTS

The median neutropenic period in autologous HCT, AML induction/salvage and consolidation was 9, 26.5, and 19 days, respectively. The incidence of FN was 93.8%, 92.3%, and 81.7%, and that of BSI in initial FN was 7.2%, 7.5% and 26.3%, respectively. The incidence of oral mucositis (≥ grade 2) was 63.1%, 9.2% and 12.2%, and that of diarrhea (≥ grade 2) was 53.3%, 9.2% and 6.4%, respectively. Although there were significant differences in the incidence of shaking chills, the degree of fever and the value of CRP between patients with and without BSI in initial FN of AML chemotherapy, no significant risk factors or predictive factors for BSI were identified in autologous HCT.

CONCLUSIONS

The profile of infectious complications in autologous HCT was characterized by a high incidence of FN maybe due to mucosal damage. On the other hand, the incidence of BSI was lower compared to that in AML consolidation chemotherapy.

Clearance of blood stream infections in patients receiving extracorporeal membrane oxygenation: a retrospective single-center cohort study

BACKGROUND

There are limited data on the treatment of blood stream infections (BSIs) in patients receiving extracorporeal membrane oxygenation (ECMO). Current guidance recommends documenting clearance only in fungal and Gram-positive BSIs. This study investigates the incidence and clinical significance of blood stream infections with positive repeat cultures (BSIPRC) in ECMO as well as clinical factors that may predict positive repeat cultures.

METHODS

All BSIs in patients receiving ECMO at Brooke Army Medical Center between September 2012 and October 2021 were included in this study. BSIPRC was defined as re-isolation of the same organism on repeat blood cultures following an initial positive blood culture.

RESULTS

A total of 60 patients developed 87 BSI (38.5 BSI per 1000 ECMO days). Of the 80 (92%) BSIs who had repeat blood cultures drawn, patients had BSIPRC in 35 (44%) of cases. Fever, leukocytosis, and vasopressor requirement on day of repeat culture were not associated with persistent positivity. There was no difference in survival to discharge for patients with BSIPRC as compared to single day BSI (58% vs. 63%, p = 0.78). 19% of patients with Gram-negative bacteremia had BSIPRC, and gram-negative bacteremia in general was associated with an 83% morality.

CONCLUSIONS

There were no clinical findings that differentiated patients with BSIPRC from those who had a single day of positivity. BSI was associated with high mortality in patients with Gram-negative bacteremia. Given high incidence of positive repeat cultures being seen in Gram-negative BSIs, repeat blood cultures have utility for all BSIs in patients receiving ECMO.

High-risk international clones ST66, ST171 and ST78 of Enterobacter cloacae complex causing blood stream infections in Spain and carrying blaOXA-48 with or without mcr-9

BACKGROUND

In the last years, Enterobacter cloacae complex has become an important threat associated with nosocomial infections (including bacteraemia). These bacteria have the ability to acquire mobile genetic elements with antimicrobial resistance genes, reducing the number of therapies available for treatment of the infections they cause. Multidrug resistant isolates of the E. cloacae complex have been causing blood stream infections in a hospital in northern Spain. The aim of this study was to report the spread of E. cloacae complex isolates carrying bla_OXA-48 with or without mcr-9 which were involved in blood stream infections, in a Spanish hospital.

METHODS

All Enterobacter spp. isolates recovered from blood cultures of patients admitted to a tertiary Spanish hospital, over a five-year period were recovered. Of those, OXA-48-producing isolates were selected for further analysis (19 E. xiangfangensis isolates and a single E. hoffmannii). Bacterial identification, antimicrobial susceptibility, DNA sequencing, molecular typing, resistome analysis and plasmid characterization was performed.

RESULTS

20 isolates were positive for bla_OXA-48, harbored by IncL/M plasmids. They belonged to the international high-risk clones ST66, ST171 and ST78. They produced the extended-spectrum β-lactamases CTX-M-15 and/or CTX-M-9 and 40 % of them (n = 8) also carried the mcr-9 gene, located on IncHI2 plasmids. However, they were susceptible to colistin.

CONCLUSION

The presence of bla_OXA-48, together with at least one bla_CTX-M gene in our multidrug resistant high-risk E. cloacae complex clones is worrisome. Also, the additional presence of mcr-9 in some of them is of concern as it could potentially be transferred into other hosts or acquire mutations that might led to emerging colistin resistance. Surveillance systems are essential to detect these difficult-to-treat bacteria which, apart from causing live-threatening infections, can spread important resistance threats.

Bacterial incidence and drug resistance from pathogens recovered from blood, cerebrospinal and pleural fluids in 2019-2020. Results of the Invifar network

Background

Antimicrobial resistance is a global concern. Analysis of sterile fluids is essential because microorganisms are defined as significant in most cases. Blood, cerebrospinal, and pleural fluids are frequently received in the microbiology lab because they are associated with considerable rates of morbi-mortality. Knowledge of epidemiology in these samples is needed to choose proper empirical treatments due to the importance of reducing selection pressure.

Methods

We used retrospective laboratory data of blood, CSF, and pleural fluid collected from patients in Mexico between 2019 and 2020. Each laboratory identified the strains and tested susceptibility using its routine methods. For Streptococcus pneumoniae, a comparative analysis was performed with data from the broth microdilution method.

Results

Forty-five centers participated in the study, with 30,746 clinical isolates from blood, 2,429 from pleural fluid, and 2,275 from CSF. For blood and CSF, Staphylococcus epidermidis was the most frequent. For blood, among gram negatives, the most frequent was Escherichia coli. Among Enterobacterales, 9.8% of K. pneumoniae were carbapenem-resistant. For S. pneumoniae, similar resistance percentages were observed for levofloxacin, cefotaxime, and vancomycin. For CSF, the most frequent gram-negative was E. coli. In Acinetobacter baumannii, carbapenem resistance was 71.4%. The most frequent species detected for pleural fluid was E. coli; in A. baumannii, carbapenem resistance was 96.3%.

Conclusion

Gram-negative bacteria, with E. coli most prevalent, are frequently recovered from CSF, blood, and pleural fluid. In S. pneumoniae, the routine, conventional methods showed good agreement in detecting resistance percentages for erythromycin, levofloxacin, and vancomycin.

Reducing catheter related bloodstream infection risk of infant with a prophylactic antibiotic therapy before removing peripherally inserted central catheter: A retrospective study

PURPOSE

This study examined the efficacy of prescribing antibiotics, specifically a single dose of vancomycin, in reducing the incidence of culture-positive and culture-negative sepsis prior to the removal of peripherally inserted central catheters (PICCs).

MATERIALS AND METHODS

We retrospectively reviewed charts of infants who had PICCs in a tertiary level hospital during the period from 2010 to 2019. The incidence of post-catheter removal clinical sepsis between the groups with or without antibiotics was compared. The antibiotic group was defined by receiving a single dose of vancomycin or any other antibiotic prior to line removal.

RESULTS

We enrolled 585 PICC removal episodes in 546 infants for analysis. Antibiotics were given prior to removal in 257 cases (43.9%) and not given prior to removal in 328 cases (56.1%). There were 13 episodes of post-catheter removal clinical sepsis detected within 72 h (2.2%), 2 of which were culture-positive (0.3%). A 9.3-fold decrease in the odds for clinical sepsis was observed in the antibiotic group (p = 0.01). The incidence of post-catheter removal sepsis was decreased by a single prophylactic dose of vancomycin (p = 0.02), whereas the use of other antibiotics showed no effect (p = 0.35). Logistic regression analysis demonstrated that comorbidities with gastrointestinal diseases (p = 0.01), PICC insertion sites in the scalp and neck (p = 0.04), and no vancomycin administration prior to line removal (p = 0.02) were independent risk factors for subsequent clinical sepsis.

CONCLUSION

A single prophylactic dose of vancomycin prior to PICC line removal might reduce clinical sepsis events in infants.

The cost of hospitalizations for treatment of hemodialysis catheter-associated blood stream infections in children: a retrospective cohort study

BACKGROUND

Hospitalization costs for treatment of hemodialysis (HD) catheter-associated blood stream infections (CA-BSI) in adults are high. No studies have evaluated hospitalization costs for HD CA-BSI in children or identified factors associated with high-cost hospitalizations.

METHODS

We analyzed 160 HD CA-BSIs from the Standardizing Care to Improve Outcomes in Pediatric End-stage Kidney Disease (SCOPE) collaborative database linked to hospitalization encounters in the Pediatric Health Information System (PHIS) database. Charge-to-cost ratios were used to convert hospitalization charges reported in PHIS database to estimated hospital costs. Generalized linear mixed modeling was used to assess the relationship between higher-cost hospitalization (cost above 50^th percentile) and patient and clinical characteristics. Generalized linear regression models were used to assess differences in mean service line costs between higher- and lower-cost hospitalizations.

RESULTS

The median (IQR) length of stay for HD CA-BSI hospitalization was 5 (3-10) days. The median (IQR) cost for HD CA-BSI hospitalization was $18,375 ($11,584-$36,266). ICU stay (aOR 5.44, 95% CI 1.62-18.26, p = 0.01) and need for a catheter procedure (aOR = 6.08, 95% CI 2.45-15.07, p < 0.001) were associated with higher-cost hospitalization.

CONCLUSIONS

Hospitalizations for HD CA-BSIs in children are often multiple days and are associated with substantial costs. Interventions to reduce CA-BSI may reduce hospitalization costs for children who receive chronic HD. A higher resolution version of the Graphical abstract is available as Supplementary information.

Ceftolozane/tazobactam for the treatment of bacteremia: a systematic literature review (SLR)

Background

Bloodstream infections (BSIs), or bacteremia, are responsible for considerable disease burden. Increasing rates of antibiotic resistance and delays in selection of appropriate treatment lead to increased morbidity, mortality, and costs. Due to limitations of current standard treatments, especially for bacteremia caused by resistant pathogens, a systematic literature review (SLR) was conducted to understand the utilization of ceftolozane/tazobactam (C/T) in bacteremia.

Methods

Electronic database searches of EMBASE^®, MEDLINE^®, CCTR and Northern Lights, as well as hand searches of conference proceedings from the last two annual meetings (i.e., 2018, 2019) of the European Congress of Clinical Microbiological and Infectious Diseases (ECCMID) and the Infectious Diseases Society of America’s annual meeting (IDWeek) were conducted. A total of 23 studies reporting on patients with bacteremia receiving C/T were included in the review.

Results

Most studies were observational (k = 20 studies), though few interventional studies were also identified (k = 3). Heterogeneity was ubiquitous with respect to source of bacteremia (i.e., primary or secondary), source of infection (for secondary bacteremia), pathogen type, antibiotic resistance, C/T dose, and outcome definitions. This heterogeneity, along with limited data, and small sample sizes (n = 1 to 31) made it difficult to draw any substantial conclusions, though overall results were favorable to C/T with respect to the outcomes of interest. Nineteen studies reported clinical cure or success (primary bacteremia: k = 6, reported range: 33.3% to 100%; secondary bacteremia: k = 8, 60% to 100%; mixed/unspecified bacteremia: k = 10, 50% to 91.7%). Eight studies reported microbiological cure or eradication rates (primary: k = 3, all reporting 100%; secondary: k = 4, 68% to 80%; mixed/unspecified: k = 5, 60% to 80%). Thirteen studies reported mortality (primary: k = 4, 0% to 14%; secondary: k = 7, 0% to 100%; or mixed/unspecified bacteremia: k = 7, 0% to 51.6%). One study each also reported composite clinical response, relapse, hospital re-admission, and hospital length of stay.

Conclusions

Although the available evidence and observed trends for C/T in bacteremia should be interpreted with caution, the direction of effect would support the utilization of C/T for these difficult to treat infections. Future research should supplement the existing evidence by considering the impact of key treatment effect modifiers without contributing to the observed heterogeneity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-022-00528-0.

Dental caries as a risk factor for bacterial blood stream infection (BSI) in children undergoing hematopoietic cell transplantation (HCT)

Background

Hematopoietic cell transplantation (HCT) is a potentially curative therapy for a wide range of pediatric malignant and nonmalignant diseases. However, complications, including blood stream infection (BSI) remain a major cause of morbidity and mortality. While certain bacteria that are abundant in the oral microbiome, such as S. mitis, can cause BSI, the role of the oral microbial community in the etiology of BSI is not well understood. The finding that the use of xylitol wipes, which specifically targets the cariogenic bacteria S. mutans is associated with reduced BSI in pediatric patients, lead us to investigate dental caries as a risk factor for BSI.

Methods

A total of 41 pediatric patients admitted for allogenic or autologous HCT, age 8 months to 25 years, were enrolled. Subjects with high dental caries risk were identified as those who had dental restorations completed within 2 months of admission for transplant, or who had untreated decay. Fisher's exact test was used to determine if there was a significant association between caries risk and BSI. Dental plaque and saliva were collected on a cotton swab from a subset of four high caries risk (HCR) and four low caries risk (LCR) children following pretransplant conditioning. 16SrRNA sequencing was used to compare the microbiome of HCR and LCR subjects and to identify microbes that were significantly different between the two groups.

Results

There was a statistically significant association between caries risk and BSI (p < 0.035) (Fisher's exact test). Multivariate logistic regression analysis showed children in the high dental caries risk group were 21 times more likely to have BSI, with no significant effect of age or mucositis severity. HCR subjects showed significantly reduced microbial alpha diversity as compared to LCR subjects. LEfse metagenomic analyses, showed the oral microbiome in HCR children enriched in order Lactobacillales. This order includes Streptococcus and Lactobacillus, both which contain bacteria primarily associated with dental caries.

Discussion

These findings support the possibility that the cariogenic microbiome can enhance the risk of BSI in pediatric populations. Future metagenomic analyses to measure microbial differences at, before, and after conditioning related to caries risk, may further unravel the complex relationship between the oral microbiome, and whether it affects health outcomes such as BSI.

Epidemiology, aetiology and clinical characteristics of clostridial bacteraemia: a 6-year population-based observational study of 386 patients

The objective of this study is to provide a population-based clinical, epidemiological and microbiological overview of clostridial bacteraemia. All cases of bacteraemia in the Skåne Region between 2014 and 2019 with a species currently belonging to the Clostridium genus were identified in the regional clinical microbiology database. Clinical data were retrieved by medical chart-review. A total of 386 unique episodes of clostridial bacteraemia were found resulting in an incidence rate of 4.9/100.000 person-years. The median age was 76 with 56% males. The incidence rate ratio was 34.3 for those aged 80 + vs 0–59. The minimum inhibitory concentrations varied between species but were universally low for metronidazole and carbapenems. Malignancy was the most common co-morbidity, in 47% of patients and most pronounced for C. septicum. Criteria for sepsis and septic shock were met in 69% and 17%, respectively. The 28-day mortality was 26%. High age, absence of fever, high C-reactive protein and high SOFA-score were all significantly associated with mortality. We present the highest incidence rate of clostridial bacteraemia to date. Clostridial bacteraemia is a severe condition with acute onset, affecting elderly with co-morbidities, most pronounced malignancies. Mortality is related to acute manifestations rather than to background factors.

Gastrointestinal colonization of Extended-Spectrum Beta lactamase producing bacteria among children below five years of age hospitalized with fever in Dar es Salaam, Tanzania

BACKGROUND

Gastrointestinal colonization of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) is of concern because prior colonization increases risk for subsequent infections. To date, the link between ESBL-PE fecal carriage and the risk of subsequent ESBL-PE infection has not been well established, and information on carriage of such pathogens among children with invasive infections such as blood stream infections (BSI) remains to be explored worldwide.

METHODS

This cross-sectional study was conducted among childrenunder the age of 5 years admitted for febrile illness in Dar es Salaam, Tanzania, between March 2017 and July 2018. We used rectal swabs to screen for ESBL-PE using selective media, ChromID® ESBL. Bacterial isolates were identified by MALDI-TOF.Blood cultures were drawn from all children. Antimicrobial susceptibility testingwas done using disk diffusion method. ESBL alleles were identified by Real-Time PCR and sequencing.

RESULTS

The overall prevalence of ESBL-PE carriage was 56% (112/200) and washighestamong children 4-6 months old (17/21, 81%) (p =0.05). Children with BSI had high ESBL-PE carriage (78.4%) compared to those without BSI (53.1%)(p=0.02; AOR 3.4, 95% CI1.20-9.58).The most common isolate was E.coli (64/112, 45%). Sixteen pairs of ESBL-PEisolates(from the gut and from blood)had similar antimicrobial susceptibility profile. We detectedbla_CTX-M gene in 97% of all phenotypically detected ESBL-PE; among those,bla_CTX-M-15 was dominant (99%).

CONCLUSIONS

We report a high prevalence of ESBL-PEfecal carriage among children with BSI in Tanzania. Colonization of ESBL-PEwasa risk factor for ESBL-BSI.

Clinical utility of oral management in allogeneic hematopoietic stem cell transplantation recipients: microbiological evidence based on molecular analysis of oral bacteria

PURPOSE

This study aimed to clarify the clinical utility of oral management to prevent bloodstream infections by oral bacteria microbiologically in patients undergoing allogeneic hematopoietic stem cell transplantation (ASCT).

METHODS

Ten consecutive patients with hematological malignancies undergoing ASCT were enrolled in this study. We implemented dental treatments before transplantation, if required, and carried out oral hygiene instructions and oral management every other day after transplantation. Molecular analysis of bacterial DNA for seven oral species using a polymerase chain reaction (PCR) assay was performed for oral samples and peripheral blood once a week for 3 weeks after transplantation.

RESULTS

Periodontitis was found in all 10 patients (mild grade in 3 and middle grade in 7) for whom basic periodontal therapy was conducted. Necessary dental procedures, including tooth extraction were performed in 5 patients. After transplantation, oral mucositis occurred in 10 patients (grade 1 in 3, grade 2 in 2, and grade 3 in 5) for whom oral hygiene instruction and oral care were continued every other day. PCR-identified three to six bacterial species in oral samples from nine patients, but none in peripheral blood from any patient during the observation period.

CONCLUSIONS

Our study suggests that oral management could prevent bloodstream infections by oral bacteria in ASCT recipients despite the existence of periodontitis or oral mucositis. Its utility was confirmed by microbiological evidence based on molecular data.

Intensive oral care can reduce bloodstream infection with coagulase-negative staphylococci after neutrophil engraftment in allogeneic hematopoietic stem-cell transplantation

PURPOSE

Bloodstream infection (BSI) is a major complication of allogeneic hematopoietic stem-cell transplantation (allo-SCT). There are several causes of BSI; in particular, severe oral mucositis (OM) can induce BSI due to coagulase-negative staphylococci (CoNS). The OM severity may be reduced with intensive oral care. Thus, we evaluated whether the type of oral care affects the BSI incidence eventually.

METHOD

We performed retrospective analysis on 206 recipients who underwent allo-SCT from 2006 to 2017 at our institute. Intensive oral care by a dental specialist was performed for 111 recipients (intensive-care group) and self-oral care was performed by 95 recipients (self-care group). Incidence of BSI was assessed by type of the oral care, before neutrophil engraftment (pre-E-BSI) and after neutrophil engraftment (post-E-BSI) period until 180 days after allo-SCT.

RESULT

A total of 112 BSI occurred in 90 of the 206 recipients and 120 bacteria were identified, with CoNS being the most prevalent. There was no significant difference in the incidence of pre-E-BSI between the self-care and intensive-care groups (30.8% and 30.6%, respectively; P = 0.508). Meanwhile, the incidence of post-E-BSI was significantly lower in the intensive-care group than in the self-care group (14.3% and 28.6%; P = 0.008). In addition, the intensive-care group had significantly lower incidence of post-E-BSI with CoNS than the self-care group (8.5% and 21.5%, respectively; P = 0.009).

CONCLUSION

Intensive oral care through the period of allo-HCT can significantly reduce the post-E-BSI occurrence, especially due to CoNS.

Hemoadsorption with CytoSorb® and the early course of linezolid plasma concentration during septic shock

Hemoadsorption with CytoSorb^® becomes increasingly established in treatment of various, predominantly inflammation-associated diseases. In septic shock, results suggest improvements in hemodynamics and organ function. However, little is known about the in vivo adsorption properties for various antibiotics. We present the case of a 61-year-old female patient with known Ulrich Turner syndrome who treated supportively with CytoSorb^® and with linezolid due to a Staphylococcus epidermidis bloodstream infection as part of her intensive care treatment for septic shock. After establishment of a new adsorber, 600 mg of linezolid administered over 1 h. Linezolid levels measured before adsorber inlet (c_pre) and after adsorber outlet (c_post) at 0, 15, 60, 120 and 480 min after starting infusion. Out of the ten samples, only the cpre samples 60 min (3.25 mg/l) and 120 min (4.7 mg/l) showed sufficiently high linezolid levels (therapeutic range 3–9 mg/l). After 480 min, cpre decreased to 2.8 mg/l, cpost increased to 1.85 mg/l, and thus clearance decreased to 67.86 ml/min (from 200 ml/min at 60 min), with greatly reduced adsorption capacity of CytoSorb^® after 8 h. A loading dose (additional 600 mg) would have been urgently needed. Linezolid therapy under hemadsorption with CytoSorb^® requires a clear indication and close monitoring of levels to avoid underdosing.

The appropriate frequency of dressing for percutaneous central venous catheters in preventing catheter-related blood stream infection in NICU - A randomized controlled trial

BACKGROUND

Complications of percutaneous central venous catheters (PCVCs) include catheter-related blood stream infection (CRBSI), occlusion, leakage, and phlebitis, which may lead to sepsis or prolonged hospitalization. The primary objective of this randomized controlled trial was to determine the appropriate frequency of dressing for percutaneous central venous catheters in preventing CRBSI, every week regularly vs. non-regularly, in premature neonates in NICU.

METHODS

Patients in NICU requiring PCVCs from March 2019-May 2020 were enrolled. Enrolled patients were randomly assigned into 2 groups: regular dressing group (RD), for which dressings were changed every week regularly, or additionally when oozing was noticed; and non-regular dressing group (ND), for which dressings were changed only when oozing was visible. The incidence of CRBSI, occlusion, leakage, and phlebitis were compared between the two groups using the Chi-squared test. The incidence of catheter-related complications was defined as numbers of episodes per 1000 catheter-days.

RESULTS

A total of 197 PCVCs were enrolled. The ND and RD groups had 99 and 98 PCVCs, respectively. The average CD interval was 9.3 days in ND group and 5.8 days in RD group. The incidence of CRBSI in RD group was 0‰, which was significantly lower than that of ND group, which was 2.0‰ (p = 0.048), but no significant differences were found between groups in the incidence of occlusion, leakage, and phlebitis of PCVCs.

CONCLUSION

Regular dressing changes every week and when oozing occurs while maintaining the protocol of maximum sterile barrier precautions is the best method and frequency of dressings of PCVCs.

Validation of an Isothermal Amplification Platform for Microbial Identification and Antimicrobial Resistance Detection in Blood: A Prospective Study

Background: Recent advances in nucleic acid amplification technique (NAAT)-based identification of pathogens in blood stream infections (BSI) have revolutionized molecular diagnostics in comparison to traditional clinical microbiology practice of blood culture. Rapid pathogen detection with point-of-care diagnostic-applicable platform is prerequisite for efficient patient management. The aim of the study is to evaluate an in-house developed, lyophilized OmiX-AMP pathogen test for the detection of top six BSI-causing bacteria along with two major antimicrobial resistance (AMR) markers of carbapenem and compare it to the traditional blood culture-based detection.

Materials and methods: One hundred forty-three patients admitted to the Medical Intensive Care Unit, Narayana Hrudayalaya, Bangalore, with either suspected or proven sepsis, of either gender, of age ≥18 years were enrolled for the study. Pathogen DNA extracted from blood culture sample using OmiX pReP method was amplified at isothermal conditions and analyzed in real time using OmiX Analysis software.

Results: Among the processed 143 samples, 54 were true negative, 83 were true positive, 3 were false negative, and 2 were false positive as analyzed by OmiX READ software. Gram-negative bacteria (91.3%) and gram-positive bacteria (75%) were detected with 100% specificity and 95.6% sensitivity along with the AMR marker pattern with a turnaround time of 4 hours from sample collection to results.

Conclusion: OmiX-AMP pathogen test detected pathogens with 96.5% concordance in comparison to traditional blood culture. Henceforth, OmiX-AMP pathogen test could be used as a readily deployable diagnostic kit even in low-resource settings.

How to cite this article: Maheshwarappa HM, Guru P, Mundre RS, Lawrence N, Majumder S, Sigamani A, et al. Validation of an Isothermal Amplification Platform for Microbial Identification and Antimicrobial Resistance Detection in Blood: A Prospective Study. Indian J Crit Care Med 2021;25(3):299–304.

The Seraph®-100 Microbind Affinity Blood Filter Does Not Affect Vancomycin, Tacrolimus, and Mycophenolic Acid Plasma Concentrations

Extracorporeal blood purification is considered an adjunct therapy in critically ill patients with life-threatening conditions such as sepsis and septic shock. It consists of cytokine removal, removal of endotoxins, a combination of both, or the removal of pathogens themselves. The latter technique was introduced for clinical application very recently. This case study describes a case of a 69-year-old female lung transplant recipient patient with a persistent VV-ECMO-related septic deep vein thrombosis with continuous renal replacement therapy-dependent acute kidney injury initiated on the Seraph®-100 Microbind Affinity Filter in order to control the persistent bacteraemia with coagulase-negative staphylococci. Drug plasma concentrations (vancomycin, tacrolimus, and mycophenolic acid) were measured before and after the device to calculate absorber-related drug clearance.

Effectiveness of a central line associated blood stream infection protocol in a pediatric population

BACKGROUND

Central line associated bloodstream infections are a common cause of bacteremia and sepsis in pediatric patients with intestinal failure, secondary to long-term CVC use.

METHODS

An IRB approved retrospective chart review was conducted on TPN-dependent patients with IF who had an identified CLABSI and presented to Children's of Alabama's emergency department (ED) and were admitted to the hospital.

RESULTS

Forty-four patients were included in the study, 28 in the first 18-month period and 26 in the second, with 10 in both populations. After implementation, mean time from ED presentation to antibiotic ordered and ED admission to antibiotic administered were lower. Mean time between antibiotic administration and admission to the floor was greater, and number of infectious disease consultations was greater. Floor-ICU transfers were lower, readmissions within 30 days was similar, and mean length of stay was similar.

CONCLUSION

A collaborative, multidiscipline-supported protocol for the care of patients with IF presenting to the ED enhances efficiency of antibiotic ordering/administration, as well as reduces the number of unplanned floor-ICU transfers.

The first Indian viridescent Acinetobacter lwoffii

Many pathogenic organisms do produce different types of the pigments, helpful in the presumptive laboratory diagnosis of the microorganisms. These pigments are malevolent as well as benevolent to the mankind. Most of the time, the pigmented organisms do display resistance to the many classes of the drugs in vitro and in vivo. Most of Acinetobacter sp are nonpigmented. Few strains produce diffusible brown pigment and rarely produce black and indigo coloured pigments (Liu1 and Nizet, 2009; Nosanchuk and Casadevall, 2003; Moazamian et al., 2018; Saviola, 2018; Saviola, 2014; Kirti et al., 2014; German et al., 2018; Coelho-Souza et al., 2014) [1-8]. This is the first Indian human case report is of "The Viridescent Acinetobacter lwoffii" (dark green pigmented) isolated from the central line blood culture which was susceptible to the many classes of the drugs in vitro and correlated well with in vivo compliance.

Prevalence of infective endocarditis in patients with positive blood cultures: a Danish nationwide study

AIMS

Increasing attention has been given to the risk of infective endocarditis (IE) in patients with certain blood stream infections (BSIs). Previous studies have been conducted on selected patient cohorts, yet unselected data are sparse. We aimed to investigate the prevalence of IE in BSIs with bacteria typically associated with IE.

METHODS AND RESULTS

By crosslinking nationwide registries from 2010 to 2017, we identified patients with BSIs typically associated with IE: Enterococcus faecalis (E. faecalis), Staphylococcus aureus (S. aureus), Streptococcus spp., and coagulase negative staphylococci (CoNS) and examined the concurrent IE prevalence. A trend test was used to examine temporal changes in the prevalence of IE. In total 69 021, distributed with 15 350, 16 726, 19 251, and 17 694 BSIs were identified in the periods of 2010-2011, 2012-2013, 2014-2015, and 2016-2017, respectively. Patients with E. faecalis had the highest prevalence of IE (16.7%) followed by S. aureus (10.1%), Streptococcus spp. (7.3%), and CoNS (1.6%). Throughout the study period, the prevalence of IE among patients with E. faecalis and Streptococcus spp. increased significantly (P = 0.0005 and P = 0.03, respectively). Male patients had a higher prevalence of IE for E. faecalis, Streptococcus spp., and CoNS compared with females. A significant increase in the prevalence of IE was seen for E. faecalis, Streptococcus spp., and CoNS with increasing age.

CONCLUSION

For E. faecalis BSI, 1 in 6 had IE, for S. aureus BSI 1 in 10 had IE, and for Streptococcus spp. 1 in 14 had IE. Our results suggest that screening for IE seems reasonable in patients with E. faecalis BSI, S. aureus BSI, or Streptococcus spp. BSI.

Peripheral intravenous catheter needleless connector decontamination study-Randomized controlled trial

BACKGROUND

Needleless connectors (NCs) were introduced to reduce health care work needlestick injuries (NSIs). If not decontaminated prior to use, NCs can be a portal for patient blood stream infections. The optimal disinfectant, and its application duration, for NC decontamination has not been empirically established.

METHODS

Factorial design randomized controlled trial comparing 70% isopropyl alcohol (IPA) and 2% chlorhexidine gluconate (CHG) in 70% IPA for 5, 10, or 15 seconds, in adult medical patients with peripheral intravenous catheters.

RESULTS

At baseline, 153 of 300 NCs (51%) grew microorganisms commonly found on the skin. Decontamination was successful in 150/153 (98%). There was no significant difference in decontamination between 70% IPA or 2% CHG in 70% IPA (P = .62), or decontamination for 5, 10, or 15 seconds (P = .21).

CONCLUSIONS

There was no difference in the effectiveness of 70% IPA and 2% CHG in 70% IPA for NC decontamination for peripheral intravenous catheters in the clinical environment. Successful decontamination was not different for applications of 5, 10, and 15 seconds; 15 seconds did not always remove all microorganisms. Factors such as cost, feasibility of compliance, and low risk of allergy support 5 seconds decontamination with 70% IPA as an acceptable approach.

A comparison of the incidence of midline catheter-associated bloodstream infections to that of central line-associated bloodstream infections in 5 acute care hospitals

In a retrospective study conducted over 12 months in a multi-hospital system, the incidence of bloodstream infections associated with midline catheters was not significantly lower than that associated with central venous catheters (0.88 vs 1.10 infections per 1,000 catheter-days). Additional research is needed to further characterize the infectious risks of midline catheters and to determine optimal strategies to minimize these risks.

Analysis of a large database

BACKGROUND

The global burden of death due to sepsis is considerable. Early diagnosis is essential to improve the outcome of this deadly syndrome. Yet, the diagnosis of sepsis is fraught with difficulties. Patients with blood stream infection (BSI) are at an increased risk of complications and death. The aim of this study was to determine the diagnostic accuracy of four readily available biomarkers to diagnose BSI in patients with suspected sepsis.

METHODS

In this retrospective, observational, Electronic Medical Record based study we compared the accuracy of procalcitonin (PCT), serum lactate concentration, total white blood cell (WBC) count and the neutrophil-lymphocyte count ratio (NLCR) to diagnose BSI in adult patients presenting to hospital with suspected sepsis. Based on the blood culture results patients were classified into 1 of the following 5 groups: i) negative blood cultures, ii) positive for a bacterial pathogen, iii) positive for a potential pathogen, iv) fungal pathogen and v) potential contaminant. Group 2 was further divided into Gram -ve and Gram +ve pathogens. Receiver operating characteristic (ROC) curves were constructed to compare the diagnostic performance of the biomarkers.

RESULTS

There were 1767 discreet patient admissions. The median PCT concentration differed significantly across blood culture groups (p < 0.0001). The highest median PCT concentration was observed in patients with a Gram-negative pathogen (17.1 ng/mL; IQR 3.6-49.7) and the lowest PCT in patients with negative blood cultures (0.6 ng/mL; IQR 0.2-2.8). The AUROC was 0.83 (0.79-0.86) for PCT, 0.68 (0.64-0.72) for the NLCR, 0.55 (0.51-0.60) for lactate concentration and 0.52 (0.48-0.57) for the WBC count. The AUROC for PCT was significantly greater than that of the NLCR (p < 0.0001). A PCT less than 0.5 ng/mL had a negative predictive value of 95% for excluding BSI. The best cut-off value of PCT for predicting BSI was 1.5 ng/ml.

CONCLUSION

Our results suggest that PCT of less than 0.5 ng/mL may be an effective screening tool to exclude BSI as the cause of sepsis, while the diagnosis of BSI should be considered in patients with a PCT above this threshold. The total WBC count and blood lactate concentration may not be reliable biomarkers for the diagnosis of BSI. The NLCR may be a useful screening test for BSI when PCT assays are not available.

Mass spectrometry-based microbiological testing for blood stream infection

BACKGROUND

The most successful application of mass spectrometry (MS) in laboratory medicine is identification (ID) of microorganisms using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) in blood stream infection. We describe MALDI-TOF MS-based bacterial ID with particular emphasis on the methods so far developed to directly identify microorganisms from positive blood culture bottles with MALDI-TOF MS including our own protocols. We touch upon the increasing roles of Liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) as well.

MAIN BODY

Because blood culture bottles contain a variety of nonbacterial proteins that may interfere with analysis and interpretation, appropriate pretreatments are prerequisites for successful ID. Pretreatments include purification of bacterial pellets and short-term subcultures to form microcolonies prior to MALDI-TOF MS analysis. Three commercial protocols are currently available: the Sepsityper® kit (Bruker Daltonics), the Vitek MS blood culture kit (bioMerieux, Inc.), and the rapid BACpro® II kit (Nittobo Medical Co., Tokyo). Because these commercially available kits are costly and bacterial ID rates using these kits are not satisfactory, particularly for Gram-positive bacteria, various home-brew protocols have been developed: 1. Stepwise differential sedimentation of blood cells and microorganisms, 2. Combination of centrifugation and lysis procedures, 3. Lysis-vacuum filtration, and 4. Centrifugation and membrane filtration technique (CMFT). We prospectively evaluated the performance of this CMFT protocol compared with that of Sepsityper® using 170 monomicrobial positive blood cultures. Although preliminary, the performance of the CMFT was significantly better than that of Sepsityper®, particularly for Gram-positive isolates. MALDI-TOF MS-based testing of polymicrobial blood specimens, however, is still challenging. Also, its contribution to assessment of susceptibility and resistance to antibiotics is still limited. For this purpose, liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) should be more useful because this approach can identify as many as several thousand peptide sequences.

CONCLUSION

MALDI-TOF MS is now an essential tool for rapid bacterial ID of pathogens that cause blood stream infection. For the purpose of assessment of susceptibility and resistance to antibiotics of the pathogens, the roles of liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) will increase in the future.

A nosocomial cluster of Roseomonas mucosa bacteremia possibly linked to contaminated hospital environment

Roseomonas, a genus of pink-pigmented glucose non-fermentative bacteria, has been associated with various primary and hospital-acquired human infections; however, to our knowledge, its nosocomial transmission has never been reported. Clinical and epidemiological investigations were carried out after two cases of R. mucosa bacteremia occurred in our hospital in 2018. Environmental samples were taken of environmental surfaces prone to water contamination in the wards and cultured. The two clinical isolates and all environmental isolates that showed growth of pink colonies were identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry and 16S rRNA gene sequencing. Pulse-field gel electrophoresis (PFGE) was performed and fingerprinting software was used to analyze the DNA restriction patterns and determine their similarity. Two patients who developed R. mucosa bacteremia had received care from the same treatment team. Of 126 environmental samples, five showed growth of R. mucosa. Using 80% similarity as the cut-off, PFGE analysis revealed that the isolates from the two patients' blood cultures and three environmental isolates belonged to the same clone. The hospital water environment was contaminated with the same clone of R. mucosa that caused bacteremia in the two patients, suggesting nosocomial transmission linked to contaminated environment. Increased vigilance is needed to monitor the emergence of Roseomonas in healthcare settings.

Evaluation of 16S rRNA broad range PCR assay for microbial detection in serum specimens in sepsis patients

BACKGROUND

Early and accurate laboratory diagnosis and appropriate management of infection improves the survival rate in sepsis. In this study we evaluated broad range 16S rRNA and 16 S-23 S intergenic spacer region (ISR) PCR assays followed by nucleotide sequencing directly from patients' serum and automated blood culture for laboratory diagnosis in admitted sepsis patients.

METHODS

A broad range 16S rRNA PCR and 16 S-23 S ISR PCR assay followed by nucleotide sequencing was used directly from patients' serum in hospital admitted patients in 62 sepsis and 16 suspected blood stream infection (sBSI) patients. Automated blood culture was also used in the same patients. Nucleotide sequences were analyzed against NCBI Genbank database and organisms were identified using CLSI MM18A guidelines.

RESULTS

Bacterial culture were positive in 10/62 (16.12%) sepsis and 3/16 (18.75%) suspected BSI patients along with 3 detected fungi (2 in sepsis and 1 in suspected BSI group). PCR assay was positive in 36/62 (58.06%) sepsis and 6/16 (37.5%) suspected BSI patients respectively. All but 2 bacteria (both from culture negative patients) detected by PCR assay could be identified from nucleotide sequencing. Survival in sepsis patients was 77%. PCR assay could detect bacteria in 9/14 (64.28%) of sepsis patients with death.

CONCLUSION

Broad range PCR assay was far superior for early diagnosis of infection. The bacteria which could not be detected by culture and were not commonly reported from this centre, were detected by the broad range PCR assays. Detection of these rare bacteria/fungi had significant clinical correlation with patient's underlying clinical conditions, immune status and prognosis. The tests could provide definitive diagnosis of infection in >58% of sepsis patients, which helped in patient management and better survival.

Fusobacterium bloodstream infections: A literature review and hospital-based case series

BACKGROUND

Infections with Fusobacterium, an anaerobic bacterium, have various clinical presentations, including bacteremia and Lemierre syndrome. Here, we report a case series of Fusobacterium bacteremia (FBB) from the largest academic center in Riyadh, Saudi Arabia, and provide a review of cases in the available literature.

METHOD

Records were retrospectively reviewed for all patients with at least one blood culture positive for Fusobacterium spp. admitted at King Khalid University Hospital, Riyadh, Saudi Arabia, between May 2015 to April 2019.

LITERATURE REVIEW

We conducted a MeSH Search on MedLine using the following terms: ("Bacteremia"[Mesh]) AND "Fusobacterium"[Mesh] for studies conducted from January 1, 1990, until March 30, 2019, excluding articles that lacked adequate clinical or microbiological details for individuals patients. Odds ratios and results of Chi-Square testing obtained in SPSS (Version 23.0, SPSS, Inc., Chicago, IL, USA) were considered statistically significant at p-values < 0.05.

RESULTS

Seven cases from our center and 205 cases from the literature were reviewed in this first reported case series for the region. Our patient series was similar to previous ones in terms of median age (45 vs. 45.5 years) and male predominance (85% vs. 65.9%). The species of Fusobacterium cultured from our cases were F. nucleatum (4 cases), F. varium (1 case), F. mortiferum (1 case), and one that could not be identified to the species level (1 case). We also report one case of FBB with renal vein thrombosis resembling that of atypical Lemierre syndrome. Analysis of literature cases revealed that bacteremia caused by the species most commonly associated with FBB, F. necrophorum, tended to be present in patients less than 40 years of age and be associated with head and neck infections and other complications, whereas F. nucleatum tended to affect people more than 40 years of age and be associated with mortality.

CONCLUSION

Although FBB is rarely reported in the literature, this case series and review of the literature suggests it is associated with morbidity and mortality. The type and duration of therapy used in these cases are underreported. Further research is needed to determine the most appropriate screening approach for FBB-associated complications and explore the relationship between FBB and specific malignancies, as well as optimal treatment type and duration.

Tunneled hemodialysis catheter care practices and blood stream infection rate in children: results from the SCOPE collaborative

OBJECTIVE

The Standardizing Care to Improve Outcomes in Pediatric End Stage Renal Disease (SCOPE) collaborative seeks to reduce hemodialysis (HD) catheter-associated blood stream infections (CA-BSI) by increasing implementation of standardized HD catheter care bundles. We report HD catheter care practices and HD CA-BSI rates from SCOPE.

METHODS

Catheter care practices and infection events were collected prospectively during the study period, from collaborative implementation in June 2013 through May 2017. For comparative purposes, historical data, including patient demographics and HD CA-BSI events, were collected from the 12 months prior to implementation. Catheter care bundle compliance in 5 care bundle categories was monitored across the post-implementation reporting period at each center via monthly care observation forms. CA-BSI rates were calculated monthly, and reported as number of infections per 100 patient months. Changes in CA-BSI rates were assessed using generalized linear mixed model (GLMM) techniques.

RESULTS

Three hundred twenty-five patients with tunneled HD catheters [median (IQR) age 12 years (6, 16), M 53%, F 47%] at 15 centers were included. A total of 3996 catheter care observations over 4170 patient months were submitted with a median (IQR) 5 (2, 14) observations per patient. Overall bundle compliance was high at 87.6%, with a significant and progressive increase (p < 0.001) in compliance for 4/5 bundle categories over the 48-month study period. The adjusted CA-BSI rate significantly decreased over time from 3.3/100 patient months prior to implementation of the care bundles to 0.8/100 patient months 48 months after care bundle implementation (p < 0.001).

CONCLUSIONS

Using quality improvement methodology, SCOPE has demonstrated a significant increase in compliance with a majority of HD catheter care practices and a significant reduction in the rate of CA-BSI among children maintained on HD.

Bloodstream infections caused by Escherichia coli carrying mcr-1 gene in hospitalized patients in northern Italy from 2012 to 2018

PURPOSE

The recurrence of multi-drug resistant (MDR) pathogens to the latest antibiotics and the limited development of new antibacterial agents have reduced the options for the treatment of severe infections. The reintroduction of old antibiotics, such as colistin, represents an effective strategy, since the latest antibiotics are over-consumed and ineffective against MDR pathogens. In 2015, Liu (Lancet Infect Dis 16:161-168, 2016) reported Escherichia coli (E. coli) isolates carrying plasmid-mediated colistin resistance gene mcr-1. The first of mcr-1 positive colistin-resistant (col-R) E. coli from a human blood culture was observed in 2012 in Latin America, while in Italy was reported for the first time by our center in 2016. The present study aimed to describe the prevalence of mcr-1 positive col-R strains in E. coli-related bloodstream infection among patients hospitalized in Fondazione IRCCS Policlinico San Matteo in Pavia, Italy, from 2012 to 2018, including the three cases already published.

METHODS

All col-R E. coli strains isolated from blood cultures collected during the study period were analyzed. The minimal inhibitory concentration of colistin was determined using broth microdilution and detection of mcr-1 and mcr-2 genes was performed by PCR. The sequence type of E. coli mcr-1 positive was determined according to Multilocus sequence typing.

RESULTS

Out of 1557 samples, 14 strains (0.90%) were col-R. and positive for the presence of the mcr-1 gene, with no mcr-2 detected. The most common ST was ST10 (n = 3), followed by ST410 (n = 2). The remaining strains exhibited different MLST profiles, indicating that they were genetically unrelated.

CONCLUSIONS

Proper reporting of the presence of mcr-1 genes is an essential component to anticipate the spread of colistin resistance. This public health issue is particularly alarming in Italy due to the consistent circulation of MDR bacteria.

Untargeted accurate identification of highly pathogenic bacteria directly from blood culture flasks

To improve the preparedness against exposure to highly pathogenic bacteria and to anticipate the wide variety of bacteria that can cause bloodstream infections (BSIs), a safe, unbiased and highly accurate identification method was developed. Our liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method can identify highly pathogenic bacteria, their near-neighbors and bacteria that are common causes of BSIs directly from positive blood culture flasks. The developed Peptide-Based Microbe Detection Engine (http://proteome2pathogen.com) relies on a two-step workflow: a genus-level search followed by a species-level search. This strategy enables the rapid identification of microorganisms based on the analyzed proteome. This method was successfully used to identify strains of Bacillus anthracis, Brucella abortus, Brucella melitensis, Brucella suis, Burkholderia pseudomallei, Burkholderia mallei, Francisella tularensis, Yersinia pestis and closely related species from simulated blood culture flasks. This newly developed LC-MS/MS method is a safe and rapid method for accurately identifying bacteria directly from positive blood culture flasks.

Clinical characteristics in blood stream infections caused by Klebsiella pneumoniae, Klebsiella variicola, and Klebsiella quasipneumoniae: a comparative study, Japan, 2014-2017

Background

Klebsiella variicola and K. quasipneumoniae are new species distinguishable from K. pneumoniae but they are often misidentified as K. pneumoniae in clinical settings. Several reports have demonstrated the possibility that the virulence factors and clinical features differ among these three phylogroups. In this study, we aimed to clarify whether there were differences in clinical and bacterial features between the three phylogroups isolated from patients with bloodstream infections (BSIs) in Japan.

Methods

Isolates from all patients with BSIs caused by K. pneumoniae admitted to two hospitals between 2014 and 2017 (n = 119) were included in the study. Bacterial species were identified via sequence analysis, and their virulence factors and serotypes were analyzed via multiplex PCR results. Clinical data were retrieved from medical records.

Results

Of the 119 isolates, 21 (17.7%) were identified as K. variicola and 11 (9.2%) as K. quasipneumoniae; K1 serotype was found in 16 (13.4%), and K2 serotype in 13 (10.9%). Significant differences in the prevalence of rmpA, iutA, ybtS, entB and kfu (p < 0.001), and allS genes (p < 0.05) were found between the three phylogroups. However, there were no significant differences in clinical features, including the 30-day mortality rate, between the three organisms, although K. variicola was more frequently detected in patients over 80 years old compared with other Klebsiella species (p < 0.005), and K. quasipneumoniae more frequently occurred in patients with malignancy (p < 0.05).

Conclusions

Our findings demonstrated the differences in bacterial pathogenicity and clinical features among these three phylogroups. Further epidemiological studies into BSI caused by Klebsiella species are warranted.

First case report of bacteremia caused by Solobacterium moorei in China, and literature review

Background

Solobacterium moorei, the only species in the genus Solobacterium, is a Gram-positive, non-spore-forming, strict anaerobic, short to long bacillus. It has rarely been documented to cause blood stream infections. Here we report the first case of bacteremia caused by S.moorei in China.

Case presentation

A 61-year-old male presented to Peking Union Medical College Hospital (Beijing) with thrombotic thrombocytopenic purpura (TTP) and several other underlying diseases. He also had persistent coma accompanied by intermittent convulsions, halitosis, and intermittent fever. Blood cultures taken when the patient had a high fever were positive, with the anaerobic bottle yielding an organism identified as S.moorei by 16S rRNA gene sequencing, whilst the aerobic bottle grew Streptococcus mitis. After replacement of venous pipeline, and empirical use of vancomycin and meropenem, the patient’s body temperature and white blood cell count returned to normal. Unfortunately, the patient died of severe TTP.

Conclusion

This is the first case report of S. moorei isolation from blood stream in China. 16S rRNA gene sequencing is the only method that can identify S. moorei. Blood cultures must be taken before administration of antibiotics, and anaerobic culture should be considered for such rare pathogens in patients with oral diseases and immune deficiency.

Influence of antibiotic treatment on the detection of S. aureus in whole blood following pathogen enrichment

Background

Early pathogen detection and identification are crucial for an effective and targeted antibiotic therapy in patients suffering from blood stream infection. Molecular diagnostic methods can accelerate pathogen identification as compared to blood culture, but frequently suffer from the inhibition of polymerase chain reation (PCR) by sample matrix components, such as host DNA, anticoagulants, or plasma proteins. To overcome this limitation, molecular diagnostic methods commonly rely on pathogen enrichment by selective lysis of blood cells and pelleting of intact pathogens prior to analysis.

Results

Here, we investigated the impact of antibiotic treatment on the recovery of pathogen DNA using an established pathogen enrichment protocol. Based on the hypothesis that induction of bacterial cell wall disintegration following antibiotic administration leads to incomplete pelleting of pathogen DNA, S. aureus was grown in human whole blood with or without addition of cell wall active (vancomycin, piperacillin) or non cell wall active (ciprofloxacin, clindamycin) antibiotics at clinically relevant concentrations. Pathogen detection remained unaffected by non cell wall active antibiotics or even increased in the presence of cell wall active antibiotics, indicating improved accessibility of pathogen DNA. Likewise, mechanical lysis of S. aureus prior to pathogen enrichment resulted in increased recovery of pathogen DNA. Quantification of pathogen and human DNA after selective lysis of blood cells and pathogen enrichment confirmed partial depletion of human DNA, leading to a net enrichment of pathogen DNA over human DNA.

Conclusion

Concurrent antibiotic administration does not reduce the recovery of pathogen DNA during pathogen enrichment by selective lysis and centrifugation.

Leads to a 10-fold human DNA depletion as compared to pathogen DNA. Moreover, we confirm that the recovery of pathogen DNA after pathogen enrichment is not negatively influenced by concurrent antibiotic administration.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1559-7) contains supplementary material, which is available to authorized users.

Multiplex polymerase chain reaction to diagnose bloodstream infections in patients after cardiothoracic surgery

Background

Sepsis and other infectious complications are major causes of mortality and morbidity in patients after cardiac surgery. Whereas conventional blood culture (BC) suffers from low sensitivity as well as a reporting delay of approximately 48–72 h, real-time multiplex polymerase chain reaction (PCR) based technologies like “SeptiFast” (SF) might offer a fast and reliable alternative for detection of bloodstream infections (BSI). The aim of this study was to compare the performance of SF with BC testing in patients suspected of having BSI after cardiac surgery.

Methods

Two hundred seventy-nine blood samples from 169 individuals with suspected BSI were analyzed by SF and BC. After excluding results attributable to contaminants, a comparison between the two groups were carried out. Receiver operating characteristic (ROC) curves were generated to determine the accuracy of clinical and laboratory values for the prediction of positive SF results.

Results

14.7% (n = 41) of blood samples were positive using SF and 17.2% (n = 49) using BC (n.s. [p > 0.05]). In six samples SF detected more than one pathogen. Among the 47 microorganisms identified by SF, only 11 (23.4%) could be confirmed by BC. SF identified a higher number of Gram-negative bacteria than BC did (28 vs. 12, χ² = 7.97, p = 0.005). The combination of BC and SF increased the number of detected microorganisms, including fungi, compared to BC alone (86 vs. 49, χ² = 13.51, p < 0.001). C-reactive protein (CRP) (21.7 ± 11.41 vs. 16.0 ± 16.9 mg/dl, p = 0.009), procalcitonin (28.7 ± 70.9 vs. 11.5 ± 30.4 ng/dl, p = 0.015), and interleukin 6 (IL 6) (932.3 ± 1306.7 vs. 313.3 ± 686.6 pg/ml, p = 0.010) plasma concentrations were higher in patients with a positive SF result. Using ROC analysis, IL-6 (AUC 0.836) and CRP (AUC 0.804) showed the best predictive values for positive SF results.

Conclusion

The SF test represent a valuable method for rapid etiologic diagnosis of BSI in patients after cardiothoracic surgery. In particular this method applies for individuals with suspected Gram-negative blood stream. Due to the low performance in detecting Gram-positive pathogens and the inability to determine antibiotic susceptibility, it should be used in addition to BC only (Pilarczyk K, et al., Intensive Care Med Exp ,3(Suppl. 1):A884, 2015).

[Distribution and drug resistance of pathogens of blood stream infection in patients with hematological malignancies after chemotherapy]

Objective: To investigate the distribution and resistance of pathogens isolated from blood cultures in patients with hematological malignancies after chemotherapy in Union Hospital of Fujian Medical University so as to understand the real situation of blood stream infection (BSI) and provide the basis for rational use of antibiotics in clinic. Methods: The data of 657 strains isolated from blood culture specimens of patients with hematological malignancies from January 2013 to December 2016 were collected analyzed. Results: A total of 657 cases of blood culture positive bacterial strains were included in the study, involving 410 cases (62.4%) with single Gram-negative bacteria (G(-) bacteria) , 163 cases (24.8%) with single Gram-positive bacteria (G(+) bacteria) , 50 cases (7.6%) with single fungi. The most common 5 isolates in blood culture were Klebsiella pneumoniae (17.5%) , Escherichia coli (17.2%) , Coagulase negative staphylococci (CNS) (14.9%) , Pseudomonas aeruginosa (14.2%) and Staphylococcus aureus (3.5%) . The extended-spectrum beta-lactamase (ESBL) production rates of Klebsiella pneumoniae and Escherichia coli were 25.2% and 55.8%, respectively. ESBL producing strains were almost more resistant than non-ESBL producing strains. The resistance rates of Enterobacteriaceae to carbapenems, piperacillin/tazobactam and tigecycline were lower than 14.0%. The resistance rates of Pseudomonas aeruginosa to a variety of drugs were lower than 12.0%. Tigecycline-resistant Acinetobacter baumannii bacteria were not detected, and the resistance rates of Acinetobacter baumannii to cefixime and cefotaxime were 7.1%. Methicillin-resistant strains in CNS (MRCNS) and in Staphylococcus aureus (MRSA) accounted for 84.7% and 43.5%, respectively. Vancomycin, linezolid and tigecycline-resistant G(+) bacteria were not detected. Conclusion: The pathogens isolated from blood culture were widely distributed. Most of them were G(-) bacteria, and the resistance to antibiotics was quite common. Furhermore, vancomycin, linezolid and tigecycline can be chosen empirically to treat patiens who ar suspected to have G(+) bacterial BSI.

[Incidence of blood stream infections of 1265 patients with hematopoietic stem cell transplantation and analysis of pathogenic bacteria]

目的

分析造血干细胞移植（HSCT）患者血流感染的发生率、病原菌分布及药敏情况，为临床血流感染的经验性治疗提供依据。

方法

对2013–2015年在苏州大学附属第一医院行HSCT的1 265例患者进行血流感染发生率、血培养阳性率、病原菌种类和耐药情况分析。

结果

1 265例HSCT患者中，有784例（61.98%）共发生1 422例次血流感染，464例（59.2%）患者处于粒细胞缺乏期（ANC<0.5×10⁹/L）。2013–2015年病原菌检出率逐年上升，总体为20.07%。检出的401株病原菌中，革兰阴性菌221株（55.1%），革兰阳性菌165株（41.2%），真菌15株（3.7%）。排名前三位为大肠埃希菌（16.0%）、表皮葡萄球菌（15.5%）和肺炎克雷伯菌（11.2%）；细菌耐药情况严峻，多重耐药的鲍曼不动杆菌和嗜麦芽窄食单胞菌比例分别为64.70%与63.64%，耐甲氧西林金黄色葡萄球菌（MRSA）比例为57.14%，均超过50.0%。耐万古霉素肠球菌（VRE）与耐碳青霉烯类抗生素肠杆菌科细菌（CRE）比例分别为14.29%、6.78%。革兰阴性菌中肠杆菌科细菌对三、四代头孢类药物耐药率较高，对碳青霉烯类抗生素耐药率较低（6.4%）。非发酵菌对抗菌药物耐药情况差别较大，对碳青霉烯类抗生素耐药率较高（47.8%）；葡萄球菌属菌株对万古霉素、替考拉宁和利奈唑胺的敏感率均为100.0%。

结论

HSCT患者血流感染发生率较高，病原菌仍以革兰阴性菌为主，非发酵菌的占比也较高，未检测到对万古霉素、替考拉宁和利奈唑胺耐药的葡萄球菌。

Risk of death after first-time blood stream infection in incident dialysis patients with specific consideration on vascular access and comorbidity

Background

The mortality following blood stream infection (BSI) and risk of subsequent BSI in relation to dialysis modality, vascular access, and other potential risk factors has received relatively little attention. Consequently, we assessed these matters in a retrospective cohort study, by use of the Danish nation-wide registries.

Methods

Patients more than 17 years of age, who initiated dialysis between 1.1.2010 and 1.1.2014, were grouped according to their dialysis modality and vascular access. Survival was modeled in time-dependent Cox proportional hazard analyses. Potential risk factors confined by a modified Charlson comorbidity index (MCCI), were subsequently assessed in stepwise selection models.

Results

At baseline, 764 patients received peritoneal dialysis (PD), and 434, 479, and 782 hemodialysis (HD) patients were dialyzed by use of arteriovenous fistulas (AVFs), tunneled catheters (TCs), and non-tunneled catheters (NTCs), respectively. We identified 1069 BSIs with an overall incidence rate of 17.7 episodes per 100 person years, and 216 BSIs occurred more than one time in the same patient. HRs of post BSI mortality relative to PD were 3.20 (95% CI 1.86–5.50; p < 0.001) with NTCs; whereas no associations were found for AVF and TC. The risk of subsequent BSIs was higher with NTCs [HR 2.29 (95% CI 1.09–4.82), p = 0.030], and no significant difference was found for AVF and TC, in relation to PD. There was an increased risk of both outcomes with TC relative to AVF [death: 1.57 (95% CI 1.07–2.29, P < 0.021); BSI: 1.78 (95% CI 1.13–2.83, P < 0.014], and risk of death was reduced in patients who changed to AVF after first-time BSI. The MCCI was significantly associated with the risk of subsequent BSI and post BSI death; however, only some of the variables contained in the index were found to be significant risk predictors when analyzed in the fitted model.

Conclusions

While NTC was the most predominant risk factor for subsequent BSI and post BSI mortality, AVF appeared protective.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3594-7) contains supplementary material, which is available to authorized users.

Risk factors and microbial profile of central venous catheter related blood stream infection in medical cardiac care units, National Heart Institute, Egypt

INTRODUCTION

Catheter related blood stream infection (CRBSI) is the main complication of central venous catheter (CVC) use. The aim of the study is to improve the safety of patients with central venous catheter in National Heart Institute (NHI) medical cardiac care units.

METHODS

A Prospective cohort study was conducted on one hundred and eleven cardiac patients in (NHI) cardiac care units from August 2017 to February 2018. All patients subjected to central venous catheter (CVC) in cardiac care units, NHI, were included except: 1. Patients with obvious source of infection, 2. Immunocompromised patients, 3. patients having infective endocarditis, 4. patients whose catheter was put outside NHI.

RESULTS

Noncompliance of health care providers to care bundle elements of CVC of Centers for Disease Control and Prevention (CDC) represents a risk factor for CRBSI occurrence. Coagulase negative staphylococci was the most common isolated organism.

CONCLUSION

Health care providers should adhere care bundle elements recommended by CDC during insertion and handling of CVC. This will in turn decrease CRBSI.

IL-13 attenuates early local CXCL2-dependent neutrophil recruitment for Candida albicans clearance during a severe murine systemic infection

To investigate the role of IL-13 during a severe systemic Candida albicans infection, BALB/c control and IL-13^-/- mice were examined for colony forming units (CFU) in the kidneys and survival days after intravenous infection. Proinflammatory mediators and cell recruitment into the tissue were measured by quantitative real-time PCR, a multiple ELISA system, and morphological cell differentiation. The IL-13^-/- group exhibited a lower CFU number in the kidneys at 4 days and survived longer than the control mice, which was accompanied by significantly higher expression of C-X-C motif ligand 2 (CXCL2), IFN-γ, and polymorphonuclear neutrophils (PMNs) in the infected kidneys. By contrast, the expression of transforming growth factor β (TGF-β) and IL-17 A on day 10 were significantly higher in the control mice than in the IL-13^-/- group. When using an intratracheal infection model, the IL-13^-/- group recruited a greater number of PMNs in 6 h, with rapidly increased CXCL2 in the alveolar space. In vitro testing with cultured bone-marrow-derived cells demonstrated rapid CXCL2 mRNA upregulation at 3 h after contact with C. albicans, which decreased with recombinant IL-13 pretreatment, whereas rIL-13 retained TGF-β upregulation. In a murine model of Candida systemic infection, preexistent IL-13 limits both the rapid CXCL2 elevation and PMN aggregation in the target organ to suppress inflammatory mediators, which also attenuates local pathogen clearance within four days.

Rapid detection of carbapenemases directly from positive blood cultures by the β-CARBA test

The rapid detection of blood stream infections (BSI) by carbapenemase-producing Enterobacterales (CPE) is indispensable to early optimize antibiotic treatment and to improve survival. While phenotypic tests are time-consuming and PCR is expensive and not available in many routine laboratories, colorimetric tests (e.g., Carba NP test) can provide rapid results at moderate cost. However, up to now, the detection of CPE-BSI requires a further 3-h incubation in broth supplemented with zinc sulfate and imipenem after a blood culture has become positive, thereby causing delay and additional hands-on time. The purpose of this study was to develop and evaluate a new method for the detection of CPE directly from positive blood culture without the need for incubation in broth, based on the commercially available colorimetric β-CARBA test. For the evaluation, blood cultures spiked with 140 different Enterobacterales isolates producing diverse beta-lactamases were tested with the new method. Of these, 70 were CPE (OXA-48-like, NDM, KPC, VIM, and GIM). After blood cultures turned positive, blood culture fluid was drawn, and erythrocytes were hemolyzed with SDS, washed, and equilibrated before the β-CARBA was performed on the bacterial pellet. All carbapenemases were reliably detected, including weak carbapenemases of the OXA-48 group. The sensitivity was 100% (95% CI 94.9-100) and the specificity 94.3% (95% CI 89.2-99.4). The time to result was 20 to 45 min. Carbapenemases can rapidly and reliably be detected directly from blood cultures using the new method, which could help to improve the outcome of these difficult-to-treat infections.

Significant infections in liver transplant recipients undergoing endoscopic retrograde cholangiography are few and unaffected by prophylactic antibiotics

INTRODUCTION

Current practice guidelines recommend prophylactic antibiotics prior to endoscopic retrograde cholangiopancreatography (ERCP) in liver transplant recipients (LTR). This study evaluated the risk of clinically significant infections after ERCP in LTR who received antibiotic prophylaxis compared to those who did not.

METHODS

This retrospective case-cohort study evaluated all LTR who underwent elective, outpatient ERCP from 2008 to 2015. Hospitalized patients, pediatric allograft recipients and patients with cholangitis or incomplete biliary drainage were excluded. The primary outcome was unanticipated hospitalization from procedure-related clinically significant infection occurring within 3 days of ERCP.

RESULTS

Sixty-nine patients (48 males; mean age 60.5 ± 7.4 years) underwent 191 ERCPs after liver transplantation. Prophylactic antibiotics were administered during 82 ERCPs and not administered for 109 ERCPs. Unscheduled admissions for fever within 3 days occurred in 4 patients. Only 2 patients had documented bacteremia, of which only 1 patient received prophylactic antibiotics and also met primary outcome. Interventions during ERCP, patient demographics, and time from transplantation were not associated with increased risk of hospitalization from infections or bacteremia.

CONCLUSIONS

The risk of infectious complications after ERCP in LTR is low and not affected by administration of prophylactic antibiotics. A tailored approach to antibiotic prophylaxis may be more appropriate than universal prophylaxis in selected LTR at low risk of infections.