Pathogens In Bloodstream Infections Research Articles

Bloodstream infections and antibiotic resistance patterns: a six-year surveillance study from southern Italy

ABSTRACT Bloodstream infections (BSI) are associated with high morbidity and mortality. This study aimed to describe the epidemiology of BSI and antimicrobial resistance patterns amongst its common bacterial causes. We conducted a retrospective record review of blood culture results of patients hospitalized with BSI at University Hospital ‘L. Vanvitelli’ from 2016 to 2021. For each patient records were obtained from the database using microbiological information. Gram-positive bacteria were the most predominant pathogens followed by Gram-negative bacteria. Among all isolates, bacterial pathogens most frequently identified included coagulase-negative Staphylococci (CoNS), Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and enterococci. We noted a general decrease in antimicrobial resistance amongst BSI pathogens in the latter years of the study. High levels of macrolide and aminoglycoside resistance amongst CoNS were reported. Carbapenem resistance amongst E. coli was barely reported, while resistance rates amongst K. pneumoniae declined considerably between 2018 and 2021. The prevalence of methicillin-resistant S. aureus decreased during the study period while that of methicillin-resistant CoNS remained relatively high throughout. The prevalence of extended spectrum ß-lactamase – producing E. coli increased considerably between 2016 and 2018 but showed a slight decrease thereafter. Conversely, there was a general decline in the resistant rates of extended spectrum ß-lactamase – producing K. pneumoniae between 2016 and 2018 with a similar trend being noted for carbapenem resistance in K. pneumoniae. Continuously monitoring the changes in the trends in BSI microbiological profiles, including pathogen profiles and the associated antibiotic resistance patterns, can help diagnostic approaches, treatment strategies and prevention programs.

Highly versus less bioavailable oral antibiotics in the treatment of gram-negative bloodstream infections: a propensity-matched cohort analysis

ObjectivesIn this study, we evaluated the clinical outcomes associated with the use of highly bioavailable oral antibiotics (fluoroquinolones and trimethoprim-sulfamethoxazole) compared with the less-bioavailable oral antibiotics (β-lactams) in gram-negative bloodstream infections (BSIs). MethodsAmong hospitalized older adult patients in Ontario, Canada, discharged home on oral treatment for gram-negative BSI between 1 January 2017 and 31 December 2019, we used a matched cohort design to compare outcomes among those receiving highly versus less-bioavailable agents; hard-matching 1:1 on sex, BSI pathogen (Escherichia coli vs. non–E. coli), and infection source (urinary vs. non-urinary/unknown source) along with a propensity score, incorporating specific pathogen, patient, and infection characteristics. The primary outcome was the composite of 90-day all-cause mortality, recurrent BSI with the same pathogen (genus and species), and re-admission to any Ontario hospital. ResultsA total of 2012 patients were included in the study (1006 in each bioavailability category). Those who received highly (compared with less) bioavailable antibiotics at discharge had lower rates of the composite outcome (171/1006 [17.0%] vs. 216/1006 [21.5%]), adjusted odds ratio being 0.74 (95% CI, 0.60–0.92). Recurrent BSI at 90 days was the main driver for the composite outcome occurring in 64 (5.4%) and 107 (9.4%) patients of the highly and less-bioavailable groups, respectively (p < 0.001) (adjusted odds ratio, 0.56; 95% CI, 0.40–0.78). DiscussionUse of highly (compared with less) bioavailable antibiotics at discharge was associated with significantly better clinical outcomes among patients with gram-negative BSIs.

Adoptive immunotherapy overcomes genetic susceptibility to bloodstream infections due to fc-gamma receptor polymorphisms after liver transplantation

Single nucleotide polymorphisms (SNPs) in FCGR3A can predict the susceptibility of liver transplant (LT) recipients to bloodstream infections (BSI) and clinical outcomes following living-donor LT (LDLT). Here, we retrospectively analyzed the relationship of adoptive immunotherapy with activated natural killer (NK) cells from perfusate effluents of liver allografts against BSI following LDLT. Higher BSI incidence and lower survival were observed in LT recipients with FcγRIIIa (158F/F or F/V) (n=81) who did not receive adoptive immunotherapy (n=55) than in those who did (n=26) (BSI frequency, 36.4% vs. 11.5%; p =.033; log-rank p =.047). After matching patient background using propensity score, similar results were obtained (BSI ratio, 41.7% vs. 12.5%; p =.049; log-rank p=.039). The predominant BSI pathogens in patients who did and did not receive adoptive immunotherapy were gram-negative rods (n=3, 100%) and gram-positive cocci (GPC) (n=15, 65.2%), respectively. The proportion of NK cells administered to patients with BSI was significantly lower than that administered to patients without BSI (Number: 80.3 (29.9-239.2)× 106 cells vs. 37.1 (35.6-50.4)× 106 ; p=.033, percentage; 14.1 (13.3-17.8)% vs. 34.6 (16.5-47)%, p=.0078). Therefore, adoptive immunotherapy with NK cells was associated with the reduced post-transplant BSI related to GPCs due to FcγRIIIa SNP in LT recipients.

A diagnostic test of real-time PCR detection in the diagnosis of clinical bloodstream infection

Blood culture remains the standard for diagnosing bloodstream infections, but it is difficult to identify bacteria directly and timeliness. The real-time polymerase chain reaction (PCR) has the potential to fill this diagnostic gap. This study intends to explore the sensitivity and specificity of PCR in detecting bloodstream infection pathogens and to compare it with routine blood culture to explore its clinical application value. A total of 126 patients with bloodstream infections collected from various clinical departments of The First Hospital of Hebei Medical University. The patient's sample was divided into two parts. The one for multiplex PCR detection was performed using the Pathogeno Elite Multiplex PCR kit. Another blood culture was a fully automatic blood culture system from Autobio company. Among the 126 patients, a total of 17 pathogens were detected by PCR and blood culture both methods. PCR detected a total of 43 positive samples and 83 negative samples. Five samples were positive with blood culture, and 81 were negative. The negative predictive value of PCR was 0.98, with a sensitivity of 0.71 and a specificity of 0.68. A total of 38 specimens were positive for PCR but negative for blood culture, and 2 samples were positive for blood culture but negative for PCR. The top 5 pathogens with PCR detection were Epstein-Barr virus (27 cases), Human herpes virus 5 (9 cases), Klebsiella pneumoniae (5 cases), Staphylococcus (5 cases), and Stenotrophomonas maltophilia (4 cases). PCR detection can rapidly identify more pathogens and even multi-pathogen infections. Therefore, PCR testing may improve pathogen detection in patients with suspected bloodstream infections, enabling targeted treatment of patients.

Identification of selected primary bloodstream infection pathogens in patients attending Kisii level five and Homa Bay county hospitals

Background: Bloodstream infection (BSI) contributes to a substantial proportion of mortality in sub-Saharan Africa and is marked by the presence of bacterial and/or fungal microorganisms in the blood. Because BSI can be life threatening, it requires a timely, reliable and accurate diagnosis. This study retrospectively analyzed data of identified BSI pathogens and compared the performance of the different diagnostic technologies used in terms of accuracy, sensitivity, turnaround time (TAT) and cost. Methods: Currently, culture followed by analytical profile index biochemical strips (API), (BioMerieux) are used as the conventional standard diagnostics in Kenyan public hospitals and labs. We compared the results of this standard to that of the BioFire FilmArray (FA) (BioFire Diagnostics) and MicroScan WalkAway-40 plus System (MS) (Beckman Coulter) used in diagnosis of BSI. The FA technology was able to identify 150/152 bacterial and yeast isolates with an overall accuracy of 99.04% (95% CI: 96.59-99.88%), sensitivity of 98.68% (95% CI: 95.33-99.84%), mean TAT of 8 hours 40 minutes per eight samples and running cost per sample of USD 140.11. The MS identified 150/152 isolates with an overall accuracy of 98.56% (95% CI: 95.86-99.70%), sensitivity of 98.68% (95% CI: 95.30-99.84%), mean TAT per sample was 42 hours and running cost per sample of USD 28.05. API detected 150/152 isolates, with an overall accuracy of 99.04% (95% CI: 96.59-99.88%), sensitivity of 98.68% (95% CI: 95.33-99.84%) and the mean TAT per sample was 53 and 103 hours for bacterial and yeast samples, respectively, with a running cost per sample of USD 28.05.Conclusions: The findings in this paper suggest that the FA and MS platforms should be able to perform adequately in Kenya referral hospitals and medical clinics as a rapid diagnostic tool.

Effective Rapid Diagnosis of Bacterial and Fungal Bloodstream Infections by T2 Magnetic Resonance Technology in the Pediatric Population.

Children are prone to bloodstream infections (BSIs), the rapid and accurate diagnosis of which is an unmet clinical need. The T2MR technology is a direct molecular assay for identification of BSI pathogens, which can help to overcome the limits of blood culture (BC) such as diagnostic accuracy, blood volumes required, and turnaround time. We analyzed results obtained with the T2Bacteria (648) and T2Candida (106) panels in pediatric patients of the Bambino Gesù Children's Hospital between May 2018 and September 2020 in order to evaluate the performance of the T2Dx instrument with respect to BC. T2Bacteria and T2Candida panels showed 84.2% and 100% sensitivity with 85.9% and 94.1% specificity, respectively. The sensitivity and specificity of the T2Bacteria panel increased to 94.9% and 98.7%, respectively, when BC was negative but other laboratory data supported the molecular result. T2Bacteria sensitivity was 100% with blood volumes <2 mL in neonates and infants. T2Bacteria and T2Candida provided definitive microorganism identification in a mean time of 4.4 and 3.7 h, respectively, versus 65.7 and 125.5 h for BCs (P < 0.001). T2 panels rapidly and accurately enable a diagnosis of a pediatric BSI, even in children under 1 year of age and for very small blood volumes. These findings support their clinical use in life-threatening pediatric infections, where the time to diagnosis is of utmost importance, in order to improve survival and minimize the long-term sequalae of sepsis. The T2 technology could be further developed to include more bacteria and fungi species that are involved in the etiology of sepsis.

Talaromyces marneffei is the Persistent Overwhelming Bloodstream Infection Pathogen Among HIV Inpatients in Fujian, China

PurposeThis study aimed to investigate the epidemiology and etiological spectrums of BSI in Fujian over the past 6 years in the post antiretroviral treatment (ART) era.MethodsA retrospective, observational study was conducted to include positive BSI inpatients with HIV between September 2015 and August 2021 in Mengchao Hepatobiliary Hospital of Fujian Medical University, the largest designated HIV/AIDS care hospital in Fujian, China. Demographic data and laboratory data including gender, age, blood cell counts, biochemistry results, CD4 and CD8 cell counts, HIV-RNA loads, pathogen isolates, procalcitonin (PCT) levels and c-reactive protein (CRP) levels were collected. Continuous variables were expressed as median (range) and Kruskal–Wallis or Mann–Whitney test was used to analyze the differences between groups. Categorical data were expressed as numbers (percentage) and the differences between groups were analyzed by Pearson’s chi-squared test.ResultsIn total, 3681 HIV inpatients with blood culture data were included and 683 strains identified from 646 inpatients were further analyzed. The median age of patients was 38 years and male accounted for 86.84%. The pooled prevalence of BSI was 18.55% (12.01%–22.36% during the six-year period). The overall isolated rate of Talaromyces marneffei (TM) in blood culture was 12.42% (8.3%–15.00% during the study period). TM was the persistent dominant BSI pathogen from 2015 to 2021 (accounting for 63.04% to 71.43%), followed by Cryptococcus neoformans (responsible for 10.00% to 20.83%). Compared to patients with other organisms BSI, those with TM BSI were younger and had lower CD4 counts, WBC counts, HB and CRP level, but higher HIVRNA loads.ConclusionBSI is still a major problem in the post ART era in hospitalized patients with HIV/AIDS in Fujian, China. TM is the predominant pathogen. This underlines the importance of an early diagnosis of opportunistic pathogen to avoid BSI in HIV-infected populations with a low immune status.

Epidemiological characteristics of bloodstream infection in patients with somatic diseases

In 1999, at the conference of the European Working Group on Nosocomial Infections, the term "bloodstream infection" was proposed in the presence of clinical symptoms and microorganisms in the bloodstream. The first classification of bloodstream infection consisted of 3 categories: hospital, iatrogenic and out-of-hospital. Then theywere classified into 5 categories. At the same time, bloodstream infection that occurred during the first 48 hours after the patient's admission to the medical organization were divided into 4 groups (AD). "Group C" included bacteremia associated with invasive procedures and was classified into 5 subgroups.&#x0D; The number of episodes of IR. The number of episodes of bloodstream infection in the world is growing depending on the geographical location of the country (from 1995 to 2002 increased by 40%, by 2007 ― by 14.3%). Among the sources of infection, the role of the respiratory, hepatobiliary, gastrointestinal, urogenital and urinary tracts, the presence of intravascular devices and pneumonia. Bloodstream infection is characterized by frequent infestation of men, staphylococcal etiology, catheter-association, and the presence of comorbid diseases. Re-episodes of Gram-negative bloodstream infection are more likely to occur within 3 months. Until 2004, Staphylococcus aureus was the leading pathogen of bloodstream infection; after 2005, Escherichia coli dominated.&#x0D; These two pathogens succeeded each other in different years. Currently, pathogens of bloodstream infection in patients with therapeutic profile are gram-positive cocci, including CNS, S. aureus, enterococci, fungi and anaerobes. Bloodstream infection is characterized by polymicrobiality (35.7%), including bacterial-fungal (22%).

Clinical validation of a multiplex droplet digital PCR for diagnosing suspected bloodstream infections in ICU practice: a promising diagnostic tool

BackgroundDroplet digital PCR (ddPCR) has emerged as a promising tool of pathogen detection in bloodstream infections (BSIs) in critical care medicine. However, different ddPCR platforms have variable sensitivity and specificity for diverse microorganisms at various infection sites. There is still a lack of prospective clinical studies aimed at validating and interpreting the discrepant ddPCR results for diagnosing BSI in intensive care unit (ICU) practice.MethodsA prospective diagnostic study of multiplex ddPCR panels was conducted in a general ICU from May 21, 2021, to December 22, 2021. Paired blood cultures (BCs) and ddPCRs (2.5 h) were obtained synchronously to detect the 12 most common BSI pathogens and three antimicrobial resistance (AMR) genes. Firstly, ddPCR performance was compared to definite BSI. Secondly, clinical validation of ddPCR was compared to composite clinical diagnosis. Sensitivity, specificity, and positive and negative predictive values were calculated. Thirdly, the positive rate of AMR genes and related analysis was presented.ResultsA total of 438 episodes of suspected BSIs occurring in 150 critical patients were enrolled. BC and ddPCR were positive for targeted bacteria in 40 (9.1%) and 180 (41.1%) cases, respectively. There were 280 concordant and 158 discordant. In comparison with BCs, the sensitivity of ddPCR ranged from 58.8 to 86.7% with an aggregate of 72.5% in different species, with corresponding specificity ranging from 73.5 to 92.2% with an aggregate of 63.1%. Furthermore, the rate of ddPCR+/BC− results was 33.6% (147/438) with 87.1% (128 of 147) cases was associated with probable (n = 108) or possible (n = 20) BSIs. When clinically diagnosed BSI was used as true positive, the final sensitivity and specificity of ddPCR increased to 84.9% and 92.5%, respectively. In addition, 40 blaKPC, 3blaNDM, and 38 mecA genes were detected, among which 90.5% were definitely positive for blaKPC. Further, 65.8% specimens were predicted to be mecA-positive in Staphylococcus sp. according to all microbiological analysis.ConclusionsThe multiplexed ddPCR is a flexible and universal platform, which can be used as an add-on complementary to conventional BC. When combined with clinical infection evidence, ddPCR shows potential advantages for rapidly diagnosing suspected BSIs and AMR genes in ICU practice.

Capsule type defines the capability of Klebsiella pneumoniae in evading Kupffer cell capture in the liver.

Polysaccharide capsule is the main virulence factor of K. pneumoniae, a major pathogen of bloodstream infections in humans. While more than 80 capsular serotypes have been identified in K. pneumoniae, only several serotypes are frequently identified in invasive infections. It is documented that the capsule enhances bacterial resistance to phagocytosis, antimicrobial peptides and complement deposition under in vitro conditions. However, the precise role of the capsule in the process of K. pneumoniae bloodstream infections remains to be elucidated. Here we show that the capsule promotes K. pneumoniae survival in the bloodstream by protecting bacteria from being captured by liver resident macrophage Kupffer cells (KCs). Our real-time in vivo imaging revealed that blood-borne acapsular K. pneumoniae mutant is rapidly captured and killed by KCs in the liver sinusoids of mice, whereas, to various extents, encapsulated strains bypass the anti-bacterial machinery in a serotype-dependent manner. Using capsule switched strains, we show that certain high-virulence (HV) capsular serotypes completely block KC's capture, whereas the low-virulence (LV) counterparts confer partial protection against KC's capture. Moreover, KC's capture of the LV K. pneumoniae could be in vivo neutralized by free capsular polysaccharides of homologous but not heterologous serotypes, indicating that KCs specifically recognize the LV capsules. Finally, immunization with inactivated K. pneumoniae enables KCs to capture the HV K. pneumoniae. Together, our findings have uncovered that KCs are the major target cells of K. pneumoniae capsule to promote bacterial survival and virulence, which can be reversed by vaccination.

Bloodstream Infections in a COVID-19 Non-ICU Department: Microbial Epidemiology, Resistance Profiles and Comparative Analysis of Risk Factors and Patients' Outcome.

Background: Bloodstream infections (BSI) caused by highly resistant pathogens in non-ICU COVID-19 departments pose important challenges. Methods: We performed a comparative analysis of incidence and microbial epidemiology of BSI in COVID-19 vs. non-COVID-19, non-ICU departments between 1 September 2020-31 October 2021. Risk factors for BSI and its impact on outcome were evaluated by a case-control study which included COVID-19 patients with/without BSI. Results: Forty out of 1985 COVID-19 patients developed BSI. The mean monthly incidence/100 admissions was 2.015 in COVID-19 and 1.742 in non-COVID-19 departments. Enterococcus and Candida isolates predominated in the COVID-19 group (p < 0.001 and p = 0.018, respectively). All Acinetobacter baumannii isolates were carbapenem-resistant (CR). In the COVID-19 group, 33.3% of Klebsiella pneumoniae was CR, 50% of Escherichia coli produced ESBL and 19% of Enterococcus spp. were VRE vs. 74.5%, 26.1% and 8.8% in the non-COVID-19 group, respectively. BSI was associated with prior hospitalization (p = 0.003), >2 comorbidities (p < 0.001), central venous catheter (p = 0.015), severe SARS-CoV-2 pneumonia and lack of COVID-19 vaccination (p < 0.001). In the multivariate regression model also including age and multiple comorbidities, only BSI was significantly associated with adverse in-hospital outcome [OR (CI95%): 21.47 (3.86–119.21), p < 0.001]. Conclusions: BSI complicates unvaccinated patients with severe SARS-CoV-2 pneumonia and increases mortality. BSI pathogens and resistance profiles differ among COVID-19/non-COVID-19 departments, suggesting various routes of pathogen acquisition.

Microbiologically confirmed infections and antibiotic-resistance in a national surveillance study of hospitalised patients who died with COVID-19, Italy 2020–2021

BackgroundPatients hospitalised for COVID-19 may present with or acquire bacterial or fungal infections that can affect the course of the disease. The aim of this study was to describe the microbiological characteristics of laboratory-confirmed infections in hospitalised patients with severe COVID-19.MethodsWe reviewed the hospital charts of a sample of patients deceased with COVID-19 from the Italian National COVID-19 Surveillance, who had laboratory-confirmed bacterial or fungal bloodstream infections (BSI) or lower respiratory tract infections (LRTI), evaluating the pathogens responsible for the infections and their antimicrobial susceptibility.ResultsAmong 157 patients with infections hospitalised from February 2020 to April 2021, 28 (17.8%) had co-infections (≤ 48 h from admission) and 138 (87.9%) had secondary infections (> 48 h). Most infections were bacterial; LRTI were more frequent than BSI. The most common co-infection was pneumococcal LRTI. In secondary infections, Enterococci were the most frequently recovered pathogens in BSI (21.7% of patients), followed by Enterobacterales, mainly K. pneumoniae, while LRTI were mostly associated with Gram-negative bacteria, firstly Enterobacterales (27.4% of patients, K. pneumoniae 15.3%), followed by A. baumannii (19.1%). Fungal infections, both BSI and LRTI, were mostly due to C. albicans. Antibiotic resistance rates were extremely high in Gram-negative bacteria, with almost all A. baumannii isolates resistant to carbapenems (95.5%), and K. pneumoniae and P. aeruginosa showing carbapenem resistance rates of 59.5% and 34.6%, respectively.ConclusionsIn hospitalised patients with severe COVID-19, secondary infections are considerably more common than co-infections, and are mostly due to Gram-negative bacterial pathogens showing a very high rate of antibiotic resistance.

Metabolic preference assay for rapid diagnosis of bloodstream infections

Bloodstream infections (BSIs) cause >500,000 infections and >80,000 deaths per year in North America. The length of time between the onset of symptoms and administration of appropriate antimicrobials is directly linked to mortality rates. It currently takes 2–5 days to identify BSI pathogens and measure their susceptibility to antimicrobials – a timeline that directly contributes to preventable deaths. To address this, we demonstrate a rapid metabolic preference assay (MPA) that uses the pattern of metabolic fluxes observed in ex-vivo microbial cultures to identify common pathogens and determine their antimicrobial susceptibility profiles. In a head-to-head race with a leading platform (VITEK 2, BioMérieux) used in diagnostic laboratories, MPA decreases testing timelines from 40 hours to under 20. If put into practice, this assay could reduce septic shock mortality and reduce the use of broad spectrum antibiotics.

Diagnosis of Bloodstream Infections: An Evolution of Technologies towards Accurate and Rapid Identification and Antibiotic Susceptibility Testing.

Bloodstream infections (BSI) are a leading cause of death worldwide. The lack of timely and reliable diagnostic practices is an ongoing issue for managing BSI. The current gold standard blood culture practice for pathogen identification and antibiotic susceptibility testing is time-consuming. Delayed diagnosis warrants the use of empirical antibiotics, which could lead to poor patient outcomes, and risks the development of antibiotic resistance. Hence, novel techniques that could offer accurate and timely diagnosis and susceptibility testing are urgently needed. This review focuses on BSI and highlights both the progress and shortcomings of its current diagnosis. We surveyed clinical workflows that employ recently approved technologies and showed that, while offering improved sensitivity and selectivity, these techniques are still unable to deliver a timely result. We then discuss a number of emerging technologies that have the potential to shorten the overall turnaround time of BSI diagnosis through direct testing from whole blood—while maintaining, if not improving—the current assay’s sensitivity and pathogen coverage. We concluded by providing our assessment of potential future directions for accelerating BSI pathogen identification and the antibiotic susceptibility test. While engineering solutions have enabled faster assay turnaround, further progress is still needed to supplant blood culture practice and guide appropriate antibiotic administration for BSI patients.

Single Center Clinical Analysis of Bloodstream Infection Pathogens in Children with Acute Leukemia

To investigate the clinical features, distribution of pathogenic bacteria, and drug resistance of bloodstream infection in children with acute leukemia. Clinical data of 93 blood culture-positive children with acute leukemia from January 2015 to December 2019 in Department of Pediatrics, The Second Hospital of Anhui Medical University were analyzed retrospectively. In these 93 cases, 78 cases were in the period of neutrophil deficiency. There were 54 Gram-negative bacteria (G-) (58.1%) found through blood culture, and the top 4 strains were Escherichia coli (15.1%), Klebsiella pneumoniae (13.9%), Pseudomonas aeruginosa (6.5%), and Enterobacter cloacae (6.5%). There were 39 Gram-positive bacteria (G+) (41.9%) detected, and the top 4 strains were Staphylococcus epidermidis (10.8%), Streptococcus pneumoniae (6.5%), Staphylococcus hemolyticus (5.4%), and Staphylococcus human (5.4%). Among 74 strains of pathogenic bacteria from acute lymphoblastic leukemia (ALL) children, there were 29 strains of G+ bacteria (39.2%) and 45 strains of G- bacteria (60.8%). While in 19 strains from acute myeloblastic leukemia (AML) patients, G- bacteria accounted for 47.4% and G+ bacteria accounted for 52.6%. In 15 ALL children without neutropenia, G+ bacteria made up the majority of the strains (66.7%). In the 93 strains of pathogenic bacteria, 13 (13.9%) strains were multidrug-resistant. Among them, extended-spectrum β-lactamases accounted for 42.9%, carbapenemase-resistant enzyme Klebsiella pneumoniae 15.4%, and carbapenemase-resistant enzyme Enterobacter cloacae strains 33.3%, which were detected from G- bacteria. While, 13.3% of methicillin-resistant coagulase-negative Staphylococci accounted for 13.3% detected from G+ bacteria, but linezolid, vancomycin, teicoplanin Staphylococcus and Enterococcus resistant were not found. The average procalcitonin (PCT) value of G- bacteria infection was (11.02±20.282) ng/ml, while in G+ infection it was (1.81±4.911) ng/ml, the difference was statistically significant (P<0.05). The mean value of C-reactive protein (CRP) in G- infection was (76.33±69.946) mg/L, and that in G+ infection was (38.34±57.951) mg/L. The prognosis of active treatment was good, and only one case died of septic shock complicated with disseminated intravascular coagulation (DIC) and gastrointestinal bleeding caused by carbapenemase-resistant enzyme enterobacteriaceae. G- is the major bacteria in acute leukemia children with bloodstream infection, but the distribution of ALL and AML strains is different. G- bacteria dominates in ALL, while G+ bacteria and G- bacteria are equally distributed in AML. Non-agranulocytosis accompanied by bloodstream infections is dominant by G+ bacteria. The mean value of PCT and CRP are significantly higher in G- bacteria infection than in G+ bacteria.

Epidemiology and Drug Resistance of Neonatal Bloodstream Infection Pathogens in East China Children's Medical Center From 2016 to 2020.

IntroductionTo analyze the pathogen distribution and drug resistance of newborns with bloodstream infection (BSI) to help clinicians choose the appropriate empirical antibiotic therapy for clinical infection control.MethodsA total of 707 neonatal BSI cases were retrospectively analyzed. The bacteria in blood culture-positive samples were cultured, identified, and analyzed for drug sensitivity by routine methods. Statistical software was used to compare and analyze the basic data, pathogenic information, and drug resistance of the main bacteria.ResultsThe 5-year average positive rate of neonatal blood culture was 2.50%. The number of specimens submitted for inspection in 2020 significantly decreased. The top five infectious pathogens with the highest proportion were coagulase-negative Staphylococcus (67.35%), of which Staphylococcus epidermidis had the highest proportion (31.26%), followed by Escherichia coli (12.87%), Klebsiella pneumoniae (9.05%), Streptococcus agalactiae (8.63%), and Staphylococcus aureus (3.25%). Gram-positive (G+) bacteria were dominant, accounting for 69.45%. The main G+ bacteria had a higher rate of resistance to erythromycin and penicillin G. The main Gram-negative (G–) bacteria had a high resistance rate to a variety of antibacterial drugs, especially cephalosporin antibiotics. The overall resistance of K. pneumoniae was higher than that of E. coli. The top two fungi detected were Candida parapsilosis and Candida albicans. C. parapsilosis did not appear to be resistant to antibiotics, while C. albicans was resistant to multiple antibiotics. The type of microbial infection had a statistically significant difference in the positive rate among the age at delivery and wards (p < 0.05). There were significant differences in the detection of fungi among these groups (p < 0.05). The positive rate of G+ bacteria in the term newborns was significantly higher than that in the preterm newborns (p < 0.05). Preterm newborns are more susceptible to pneumonia.ConclusionG+ bacteria are the main pathogens of neonatal BSI. Preterm newborns are more likely to be infected with G– bacteria. E. coli and K. pneumoniae are the most common G– bacteria, and both have a high resistance rate to a variety of antibacterial drugs. According to the distribution characteristics and drug resistance, it is very important to select antibiotics reasonably.

Distribution and drug resistance profiles of pathogens causing bloodstream infection after chemotherapy in children with acute lymphoblastic leukemia.

To study the changes in the distribution and drug resistance profiles of pathogens causing bloodstream infection after chemotherapy in children with acute lymphoblastic leukemia. The medical data were collected from the children with acute lymphoblastic leukemia who were admitted to the First Affiliated Hospital of Zhengzhou University between January 2015 and December 2020 and developed bloodstream infection after chemotherapy. The samples were divided into the first three years group and the next three years group according to the time of testing to investigate the differences in the distribution and drug resistance profiles of pathogens as time. A total of 235 strains of pathogens were isolated, among which there were 159 Gram-negative strains (67.7%; mainly Escherichia coli and Klebsiella pneumoniae), 61 Gram-positive strains (26.0%; mainly Staphylococcus epidermidis), and 15 strains of fungi (6.4%; mainly Candida albicans). There were no significant differences between the first three years group and the next three years group in the detection rate of Gram-negative bacteria (68.8% vs 66.9%, P>0.05) or Gram-positive bacteria (29.2% vs 23.7%, P>0.05). Compared with the first three years group, the next three years group had significant increases in the detection rate of Streptococcus mitis (5.8% vs 0.0%, P<0.05) and fungi (9.4% vs 2.1%, P<0.05). There was no significant difference in the drug resistance rate of Gram-negative or Gram-positive bacteria between the two groups (P>0.05). Enterobacteriaceae bacteria are the main pathogens of bloodstream infection after chemotherapy in children with acute lymphoblastic leukemia, while the detection rates of Streptococcus mitis and fungi tend to increase as time, which needs to be taken seriously in clinical practice.

Blood culture surveillance in a secondary care hospital in Benin: epidemiology of bloodstream infection pathogens and antimicrobial resistance

BackgroundAlthough global surveillance of antimicrobial resistance (AMR) is considered key in the containment of AMR, data from low- and middle-income countries, especially from sub-Saharan Africa, are scarce. This study describes epidemiology of bloodstream infections and antimicrobial resistance rates in a secondary care hospital in Benin.MethodsBlood cultures were sampled, according to predefined indications, in BacT/ALERT FA Plus and PF Plus (bioMérieux, Marcy-l’Etoile, France) blood culture bottles (BCB) in a district hospital (Boko hospital) and to a lesser extent in the University hospital of Parakou. These BCB were incubated for 7 days in a standard incubator and twice daily inspected for visual signs of growth. Isolates retrieved from the BCB were processed locally and later shipped to Belgium for reference identification [matrix-assisted laser desorption/ionization time-of-flight spectrometry (MALDI-TOF)] and antibiotic susceptibility testing (disk diffusion and E-tests).ResultsFrom October 2017 to February 2020, 3353 BCB were sampled, corresponding to 3140 blood cultures (212 cultures consisting of > 1 BCB) and 3082 suspected bloodstream infection (BSI) episodes. Most of these cultures (n = 2471; 78.7%) were sampled in children < 15 years of age. Pathogens were recovered from 383 (12.4%) cultures, corresponding to 381 confirmed BSI. 340 of these pathogens were available and confirmed by reference identification. The most common pathogens were Klebsiella pneumoniae (n = 53; 15.6%), Salmonella Typhi (n = 52; 15.3%) and Staphylococcus aureus (n = 46; 13.5%). AMR rates were high among Enterobacterales, with resistance to third-generation cephalosporins in 77.6% of K. pneumoniae isolates (n = 58), 12.8% of Escherichia coli isolates (n = 49) and 70.5% of Enterobacter cloacae isolates (n = 44). Carbapenemase production was detected in 2 Escherichia coli and 2 Enterobacter cloacae isolates, all of which were of the New Delhi metallo-beta lactamase type. Methicillin resistance was present in 22.4% of S. aureus isolates (n = 49).ConclusionBlood cultures were successfully implemented in a district hospital in Benin, especially among the pediatric patient population. Unexpectedly high rates of AMR among Gram-negative bacteria against commonly used antibiotics were found, demonstrating the clinical and scientific importance of clinical bacteriology laboratories at this level of care.

Antimicrobial resistance monitoring of potential pathogens causing bloodstream infections

Microbiological monitoring, being an integral component of epidemiological surveillance of healthcare associated infection (HAI), is one of the most important components in hospital patient safety. The purpose of monitoring is the etiological interpretation of pathogens, the identification of microbial hospital strains and development of strategies as well as tactics for combating them. In modern conditions development of healthcare and humanity as a whole, the most important problem is the steady increase in the number of HAI caused by antimicrobial drug-insensitive pathogens and decreased drug effectiveness used in therapy. The structure of infectious conditions in the hospital is specific and is determined by the profile and nature of the treatment, nosology and age of patients. The main pathogens in the etiological structure of HAI are Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumanii, Enterococcus faecalis and Enterococcus faecium. The study estimated the prevalence of bloodstream infections pathogens resistant to antimicrobial agents in healthcare facilities in St. Petersburg. We retrospectively analyzed data on the antimicrobial resistance for the six clinically significant HAI pathogens that were detected in the blood samples at the 50 hospitals of St. Petersburg during the years 2016–2019. It was found that the use of β-lactam antibiotics is not effective in the treatment of patients with bloodstream infections (BSI) caused by S. aureus (in 21.9% of BSI cases), E. coli (2.1%), Klebsiella spp. (39.6%), P. aeruginosa (40.5%), Acinetobacter spp. (66.7%), Enterococcus spp. (4.4%). This article shows that targeted microbiological monitoring of HAI caused by resistant pathogens should be considered as an effective organizational mechanism for timely detection and prevention of complications that are observed in medical care to patients at high risk for bloodstream infections. Identification of the features of the epidemic process for purulentseptic infections in medical organizations contributes to the improved preventive measures in order to improve the quality of medical care. Microbiological monitoring data are necessary for the development and implementation of measures to curb the further growth of antimicrobial resistance of infectious disease pathogens.

Scavenging of bacteria or bacterial products by magnetic particles functionalized with a broad-spectrum pathogen recognition receptor motif offers diagnostic and therapeutic applications

Sepsis is a dysregulated host response of severe bloodstream infections, and given its frequency of occurrence and high mortality rate, therapeutic improvements are imperative. A reliable biomimetic strategy for the targeting and separation of bacterial pathogens in bloodstream infections involves the use of the broad-spectrum binding motif of human GP-340, a pattern-recognition receptor of the scavenger receptor cysteine rich (SRCR) superfamily that is expressed on epithelial surfaces but not found in blood. Here we show that these peptides, when conjugated to superparamagnetic iron oxide nanoparticles (SPIONs), can separate various bacterial endotoxins and intact microbes (E. coli, S. aureus, P. aeruginosa and S. marcescens) with high efficiency, especially at low and thus clinically relevant concentrations. This is accompanied by a subsequent strong depletion in cytokine release (TNF, IL-6, IL-1β, Il-10 and IFN-γ), which could have a direct therapeutic impact since escalating immune responses complicates severe bloodstream infections and sepsis courses. SPIONs are coated with aminoalkylsilane and capture peptides are orthogonally ligated to this surface. The particles behave fully cyto- and hemocompatible and do not interfere with host structures. Thus, this approach additionally aims to dramatically reduce diagnostic times for patients with suspected bloodstream infections and accelerate targeted antibiotic therapy. Statement of significanceSepsis is often associated with excessive release of cytokines. This aspect and slow diagnostic procedures are the major therapeutic obstacles. The use of magnetic particles conjugated with small peptides derived from the binding motif of a broad-spectrum mucosal pathogen recognition protein GP-340 provides a highly efficient scavenging platform. These peptides are not found in blood and therefore are not subject to inhibitory mechanisms like in other concepts (mannose binding lectine, aptamers, antibodies). In this work, data are shown on the broad bacterial binding spectrum, highly efficient toxin depletion, which directly reduces the release of cytokines. Host cells are not affected and antibiotics not adsorbed. The particle bound microbes can be recultured without restriction and thus be used directly for diagnostics.