Bacteremia Infection Research Articles

Efficacy of loading dose colistin versus carbapenems for treatment of extended spectrum beta lactamase producing Enterobacteriaceae

Colistin provides in vitro activity against numerous ESBL-producing and carbapenem-resistant bacteria. However, clinical information with respect to its utilization in infection caused by ESBL producers is limited. The aim of this study was a comparison of mortality rates of loading dose (LD) colistin and carbapenems as definitive therapies in a cohort of patients with infections caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae. A retrospective cohort study in 396 patients with ESBL-producing E.coli and K.pneumoniae infection at a university-affiliated hospital was conducted between 1 January 2005 and 30 June 2015 to compare outcomes of infected patients who received LD colistin (95 patients) with carbapenems (301 patients). The three primary outcomes were 30-day mortality, clinical response and microbiological response. The most common infection types were urinary tract infection (49.49%), followed by pneumonia (40.66%), bacteremia (13.64%), skin and soft tissue infections (4.80%) and intra-abdominal infection (3.03%). LD colistin group provided higher 30-day mortality when compared with carbapenems group (HR 7.97; 95% CI 3.68 to 17.25; P = 0.001). LD colistin was also independently associated with clinical failure (HR 4.30; 95% CI 1.93 to 9.57; P = 0.001) and bacteriological failure (HR 9.49; 95% CI 3.76 to 23.96; P = 0.001) when compared with those who received carbapenems. LD colistin treatment was associated with poorer outcomes, i.e. mortality rate, clinical response and microbiological response. Moreover, when adjusted confounding factors, LD colistin was still less effective than carbapenems. It should be noted that, however, the use of Vitek-2 to assess colistin susceptibility could provide inaccurate results. Also, the difference in baseline characteristics could still remain in retrospective study although compensation by hazard ratio adjustment was performed. Therefore, clinical utilization of LD colistin should be recommended as an alternative for treatment ESBL-producing Enterobacteriaceae only in the circumstances where carbapenems cannot be utilized, but this recommendation must be considered carefully.

An unexpected pathogen causing multiple intra-abdominal abscesses in an immunocompetent patient

Streptococcus constellatus is a member of the group now called Streptococcus anginosus. This microorganism is part of the normal oropharyngeal, gastrointestinal and genitourinary microbiota. However, it may cause serious infections such as pharyngitis, bacteremia and invasive pyogenic infections in immunocompromised patients. We report the first case in Colombia of an adult male with no relevant medical history and with an unusual presentation of infection by S. constellatus and whose laboratory results showed an important systemic inflammatory response and radiographic evidence of abdominal involvement with poor response to medical and surgical management. Since there are few reports in international medical journals about intra-abdominal infection by S. constellatus and taking into consideration the need of a multidisciplinary intervention, this report may be of interest for both clinical and surgical practitioners.

Prosthetic joint infection in culture-negative and alpha-defensin-positive patients versus culture-positive and alpha-defensin-negative patients: a retrospective cohort study of the differences in clinical characteristics and outcomes

Background: Culture-negative (CN) prosthetic joint infection (PJI) poses a challenge for the clinician for both diagnosis and management. We compared the clinical presentation and outcomes between patients with CN alpha-defensin-positive PJI and culture-positive (CP) alpha-defensin-negative PJI. Methods: This was a retrospective study of 15 patients who underwent treatment for PJI (four hips and 11 knees) at a tertiary referral center by a single surgeon from 2016 to 2019. Patients were divided into two cohorts based on their culture results: one group had negative cultures but positive alpha-defensin test (n=7) and the other had positive cultures but negative alpha-defensin test (n=8). These two cohorts were compared in terms of clinical presentation, laboratory values, treatment duration, and functional outcome. Statistical analysis was performed on variables of interest. Results: Patients in both PJI groups most commonly presented with pain and swelling of the involved joint. There was a greater proportion of CN PJI patients with a history of infection, such as bacteremia or urinary tract infection (UTI) requiring antibiotics, than CP PJI patients (42.9% vs. 0%). There was no statistically significant difference in inflammatory marker elevation for either group. Only 57% of the CN PJI patients underwent surgical debridement versus all CP PJI patients. There were no differences in outcomes at final follow-up between the two groups. Conclusions: Prior history of infection requiring antimicrobial therapy is a risk factor for negative cultures. CN PJI is not a negative prognostic indicator and results in outcomes similar to CP PJI. Level of Evidence: Level III.

Discovery and Validation of a 3-Gene Transcriptional Signature to Distinguish COVID-19 and Other Viral Infections from Bacterial Sepsis in Adults; A Case-Control then Observational Cohort Study

Background: Emergency hospital admissions for infection often lack microbiological diagnostic certainty. Novel approaches to discriminate likelihood of bacterial and viral infections are required to support antimicrobial prescribing decisions and infection control practice. We sought to derive and validate a blood transcriptional signature to differentiate bacterial infections from viral infections including COVID-19.Methods: Blood RNA sequencing was performed on a discovery cohort of adults attending the Emergency Department with confirmed bacteraemia or viral infection. Differentially expressed host genes were subjected to feature selection to derive the most parsimonious discriminating signature. RT-qPCR validation of the signature was then performed in a prospective cohort of patients presenting with undifferentiated fever and a second case-control cohort of patients with bacteraemia or COVID-19.Findings: A 3-gene transcript signature was derived from the discovery cohort of 56 definite bacterial and 27 viral infection cases. In the validation cohort, the signature differentiated bacterial and viral infections with an area under receiver operating characteristic curve (AUC) of 0.976 (95% CI: 0.919-1.000), sensitivity 97.3% and specificity of 100%. The AUC for C-reactive protein and leucocyte count was 0.833 (95% CI: 0.694-0.944) and 0.938 (95% CI: 0.840-0.986) respectively. In the second validation analysis the signature discriminated 34 SARS-CoV-2 positive COVID-19 from 35 bacterial infections with AUC of 0.953 (95% CI: 0.893-0.992), sensitivity 88.6% and specificity of 94.1%.Interpretation: This novel 3-gene signature discriminates viral infections including COVID-19 from bacterial sepsis in adults, outperforming both leucocyte count and CRP, thus potentially providing significant clinical utility in managing acute presentations with infection.Funding Statement: Work in this study was funded by the NIHR Imperial Biomedical Research Centre, the Medical Research Council, the Wellcome Trust and the European Union FP7 (EC-GA 279185) (EUCLIDS).Declaration of Interests: None of the authors have any relevant interest to declare. Ethics Approval Statement: Ethical approval was obtained to take deferred consent from patients from whom an RNA specimen had been collected (or from next of kin or nominated consultee) (REC references 14/SC/0008 and 19/SC/0116).

Analyses of the relationships among biofilm activity, antibiotic resistance and expressions of SHV, TEM, CTX and IntI in Klebsiella pneumoniae

Aim: Klebsiella pneumoniae as an opportunistic pathogen is responsible for nosocomial, urinary tract infections, pneumonia, bacteremia, liver abscesses, and respiratory and blood infections in patients. The aim of our study is to examine the antibiotic sensitivity, expression levels of IntI, TEM, SHV and CTX genes, which play a role in multidrug resistance, biofilm formation and even the relationships among them. Materials and Methods: Identification was implemented by carrying out the VITEK2 system and phenotypic confirmation of the ESBL producing isolates by using a combined disc test. Antibiotic sensitivity was implemented by disc diffusion method and microdilution methods toward various antibiotics. Furthermore, biofilm formation was examined through microtitration plate method. Results: The expressions of IntI, TEM, SHV and CTX were implemented in qRT-PCR. 19 were susceptible to all antibiotics, 17 were ESBL (+) and 16 were carbapenem-resistant among 52. The expression of these genes was upregulated in ESBL (+) strains and produced biofilm and the expression of these genes was upregulated, too. Conclusion: The results of the study revealed the potential role of the mentioned genes in biofilm formation and antibiotic resistance, enabling the development of new drugs. Further studies will be essential so as to determine when or how these systems are included in antibiotic resistance and biofilm formation.

Experiences in outpatient parenteral antimicrobial therapy (OPAT): Barriers and challenges from the front lines.

Outpatient parenteral antimicrobial therapy (OPAT) is now the standard of care for managing patients who no longer need inpatient care but require prolonged intravenous antimicrobial therapy. OPAT increases patient satisfaction, reduces the lengths of hospital stay, lowers emergency department readmission rates, and decreases total healthcare spending. To investigate Virginia Commonwealth University Health System's experience with OPAT and to highlight the obstacles patients and clinicians face when navigating and utilizing this program. We conducted this descriptive study at a large, academic, tertiary-care hospital in Central Virginia. We performed manual reviews of electronic medical records of 602 patient, and we evaluated the records of those receiving OPAT between 2017 and 2020. Reviews included antimicrobial agents, diagnoses requiring OPAT, adverse effects related to antimicrobials, adverse effects related to peripherally inserted central catheters (PICC), readmission rate, discharge destination, and death. We evaluated our program with descriptive statistics. Among 602 patients who received OPAT, most were diagnosed with bacteremia or musculoskeletal infections. Patients were either discharged home or to another healthcare facility, with the former comprising most of the rehospitalizations. Ertapenem and vancomycin were associated with the most adverse drug events among our cohort. Elevated transaminase levels were noted in 23% of patients. The rate of PICC-line adverse events in this study population was 0.05%. Our findings highlight the barriers and challenges that patients and providers face when receiving OPAT, and they can inform efforts to improve patient clinical outcomes.

Characterisation and Antibiotic Susceptibility Pattern of Enterococci in a Tertiary Care Hospital of North East India

Introduction: Enterococci are important agents of nosocomial infection, ranking as the second most common organisms causing complicated urinary tract infections, bacteraemia, endocarditis, intra-abdominal and pelvic infections, wound and soft tissue infections, neonatal sepsis, and, rarely, meningitis. Infections by enterococci have traditionally been treated with cell wall active agents (e.g., penicillin or ampicillin) in combination with an aminoglycoside (streptomycin/gentamicin); however, emergence of High Level Aminoglycoside Resistance (HLAR), β lactam antibiotics resistance and vancomycin resistance by some strains has led to failure of synergistic effects of combination therapy. Aim: To characterise enterococci up to the species level and study their antibiotic susceptibility pattern. Materials and Methods: The present study was a cross-sectional study in which a total of 14114 clinical specimens, obtained during the period from September 2018 to August 2020 in this cross-sectional study, were tested to identify and speciate enterococcal isolates using standard microbiological methodology. Antibiotic susceptibility testing was done by Kirby Bauer disc diffusion method. Data was analysed using descriptive statistics (percentage and proportion). Results: During the study period of two years, 146 enterococci were recovered from 14114 different clinical samples, accounting for an infection rate of 1.03%. Among 146 enterococcal isolates, 116 (79.5%) were obtained from urine, 13 (8.9%) from blood, 10 (6.8%) from pus, 4 (2.7%) from wound swab and 3 (2.1%) from catheter tip. The predominant isolates were E. faecalis (82.2%) followed by E. faecium (15.8%), E.durans (1.3%) and E.gallinarum (0.7%). On studying the antibiotic susceptibility pattern, most of enterococcal isolates were predominantly resistant to ampicillin and ciprofloxacin (73.9% in both) and least resistant to linezolid (3.4%). Conclusion: Enterococcus faecalis and Enterococcus faecium were the predominant species in present study and majority of the isolates was sensitive to linezolid (96.6%). Therefore, it is necessary to implement infection control measures like antimicrobial stewardship especially restricting the use of antibiotics to minimum.

Predictors of serious bacterial infections using serum biomarkers in an infant population aged 0 to 90 days: a prospective cohort study

ObjectiveYoung febrile infants represent a vulnerable population at risk for serious bacterial infections (SBI). We aimed to evaluate the diagnostic accuracy of components of the complete blood count in comparison...

Melioidosis in Australia

Melioidosis is a potentially fatal bacterial infection caused by the Gram-negative bacillus, Burkholderia pseudomallei following contact with a contaminated environmental source, normally soil or water in tropical and subtropical locations. The disease spectrum varies from rapidly progressive bacteraemic infection with or without pneumonia, to focal lesions in deep soft tissues and internal organs to superficial soft tissue infection and asymptomatic seroconversion with possible long-term dormancy. Most infections occur with a background of chronic illness such as diabetes, chronic kidney disease and alcoholic liver disease. Improvements in diagnosis, targeted antimicrobial treatment and long term follow up have improved clinical outcomes. Environmental controls following rare point source case clusters and heightened awareness of melioidosis appear to have reduced the disease burden in some parts of northern Australia. However, the impact of climate change on dispersal of environmental B. pseudomallei, and changing land use in tropical Australia is expected to change the epidemiology of melioidosis in future.

1689. Oral Beta-lactam Step Down in Bacteremic E. coli Urinary Tract Infections

BackgroundLiterature is scarce regarding oral step down to beta-lactams in bacteremic urinary tract infections. Oral fluoroquinolones are an accepted and common step down for bacteremic urinary tract infections; however, their use is associated with mounting safety concerns. We compared clinical cure in patients with E. coli bacteremic urinary tract infections who were stepped down to oral beta-lactams compared to oral fluoroquinolones.MethodsThis multicentre retrospective cohort study included patients with first positive concurrent urine and blood cultures from January 2016 to December 2016. Patients were included if they received empiric intravenous beta-lactam therapy with step down to either oral beta-lactam or fluoroquinolone for treatment completion. The primary outcome was clinical cure. Secondary outcomes were length of hospitalization, all-cause mortality and C. difficile infection. Multivariate analysis and propensity score were used to control for confounding.ResultsA total of 207 patients were identified with bacteremic E.coli urinary tract infections. Clinical cure was achieved in 72/77 (94%) in the oral beta-lactam group versus 127/130 (98%) in the oral fluoroquinolone group (absolute difference -4.2%, 95% confidence interval [CI] -10.3% to 1.9%, p=0.13). The adjusted odds ratio (OR) for clinical cure with oral beta-lactams was 0.31 (95% CI 0.05 – 1.90, p=0.21); propensity score adjusted analysis showed a similar result. There was no statistically significant difference in secondary outcomes.Table 2 Table 3 Table 4 ConclusionOral beta-lactams appear to be a safe and effective step down option in bacteremic E. coli urinary tract infections compared to oral fluoroquinolones.Disclosures All Authors: No reported disclosures

1026. Is Empiric Coverage Necessary? Incidence of Pseudomonas aeruginosa and Methicillin-Resistant Staphylococcus aureus in Foot Infections

BackgroundEmpiric antibiotics for foot infections often include coverage of Pseudomonas aeruginosa (PA) and Methicillin-resistant Staphylococcus aureus (MRSA) due to their presumed frequency and ability to cause severe infection. The purpose of this study was to: 1) determine the incidence of PA and MRSA in foot infections; 2) identify variables associated with the presence of PA or MRSA; and 3) examine empiric antibiotic trends for foot infections to determine if empiric coverage of PA and MRSA is warranted.MethodsRetrospective study of foot infections at five large urban hospitals in San Diego during 2018. Data were collected from the medical records including demographics, host factors, laboratory data, pathology and imaging data, culture results, and empiric antibiotics. Patients with a foot infection treated as an inpatient in our healthcare system who had a culture collected were included.Results310 patients with foot infections were included. Mean age was 61.6 years; 220 (71%) were male; 248 (80%) had diabetes; 40 (13%) had end-stage renal disease (ESRD), and 122 (39%) had peripheral arterial disease (PAD). PA was present in 28 (9%) cases. No patient had a positive blood culture for PA. MRSA was present in 55 (18%) cases. Only one patient had a positive blood culture for MRSA. On univariate analysis, wound location not in the forefoot (p=0.047) and presence of PAD (p=0.048) were associated with PA. These failed to remain significant in multivariate analysis (OR=0.42, p=0.074 and OR=2.54, p=0.0504, respectively). Factors associated with MRSA included shallower depth of wound (OR=0.36; p=0.043). 199/310 patients (64%) received empiric antibiotic coverage for PA while 262/310 patients (85%) received empiric MRSA coverage. Of those who received empiric anti-PA coverage, 174 were overtreated (87%). Of those who received empiric anti-MRSA coverage, 218 (83%) were overtreated.ConclusionThe incidence of PA in foot infections was overall low, and none had positive blood cultures. MRSA was more often present, however, most patients did not have bacteremia or severe infections. In our study, the majority of empiric anti-PA, as well as anti-MRSA, antibiotic coverage for foot infections was unnecessary questioning the need for upfront, empiric coverage for these pathogens in foot infections.Disclosures All Authors: No reported disclosures

883. Evaluation of Post-operative Antibiotic Prophylaxis in Patients Undergoing Urologic Procedures

BackgroundMany national guidelines do not recommend post-operative antibiotic prophylaxis due to lack of literature supporting its use; however, they are frequently prescribed at ChristianaCare for urologic procedures. Use of post-operative antibiotics has not correlated with reduction in post-operative infections, and has been show to increase risk for resistant infections, Clostridiodes difficile (C. difficile) and acute kidney injury (AKI).MethodsA single center retrospective chart review was conducted to evaluate endpoints of patients who underwent a urologic procedure and received post-operative antibiotics (intervention group) compared to those who did not (control group) from June 1st 2018 to September 1st 2019. The primary endpoint was to compare the incidence of post-operative infections, including surgical site infections (SSIs), bacteremia, and urinary tract infections (UTIs) between the intervention and control groups. The secondary endpoints included comparing the incidence of prespecified adverse outcomes, between the two groups.ResultsA total of 250 patients were included in this study. Baseline demographics were similar across a number of characteristics in both groups. There was no difference between the intervention and control groups in the incidence of post-operative bacteremia (p = 0.608), SSIs (p = 0.491) and 30 day UTIs (p = 0.307). The rate of AKI between both groups were similar. There was a higher percentage of resistant organisms seen in the intervention group compared to the control group (21.4 % vs. 16.7%). The intervention group experienced an increase in post-operative antibiotic related adverse effects. Although a small number of patients were tested for C. difficile, there was one positive C. difficile PCR in the intervention group compared to zero in the control group.ConclusionThe results of this study support withholding post-operative antibiotics in urologic procedures given no benefit in reducing post-operative infections and potential to increase adverse effects and development of resistant organisms. Efforts to change this current practice at our institution will be implemented via collaboration with the urology section and review of current order sets.Disclosures Jillian Laude, Pharm D, BCPS, Shionogi Inc (Other Financial or Material Support, Received one-time speaker fee for a round table discussion. The financial relationship does not relate to this research project.)

851. Compliance with Guidelines for Management of Staphylococcus aureus Bacteremia and its Effect on Mortality

BackgroundIn the US, Staphylococcus aureus Bacteremia (SAB) occurs in about 19.7 /100,000 people. A recent increase in methicillin-resistant Staphylococcus aureus (MRSA) bacteremia infections rate and mortality has led to more infectious diseases (ID) consultations. We assessed if an infectious diseases consultation within 7 days of initial blood culture results was associated to greater compliance with Infectious Diseases Society of America (IDSA) guidelines for managing Staphylococcus aureus bacteremia and a decrease in all-cause mortality and relapse within 90 days.MethodsA retrospective cohort of patients admitted to two community hospitals from January 2014 to June 2016 with a positive blood culture for methicillin-susceptible S. aureus (MSSA), MRSA, or coagulase-negative Staphylococcus were included in the study. I. Patients were excluded if they were immunocompromised, had a polymicrobial blood stream infection, died within first 48 hours of admission, left against medical advice during treatment or participated in another study requiring an alternative treatment strategy.ResultsA total of 331 patients were included in the analysis. A significantly higher proportion of patients with complicated SAB had an ID consult (61% vs. 17.5%, p< .0001) and for uncomplicated SAB the reverse was true (39% vs 79%, P< .0001). An ID consult was associated with increased compliance with IDSA guidelines (75% vs. 5%, p< .0001). Patients with an ID consult had a significantly higher duration of antibiotic treatment [30(14-42) vs. 5(1.5-12), p< .0001], an earlier start of treatment in number of days [0(0-7) vs. 0(0-12), p=0.036] and a lower mortality within 90 days of blood culture (61% vs. 17.5%, p< .0001). Logistic regression model showed than an ID consult reduced 90-day mortality by 69%, OR 0.313[CI 95 %(0.313-0.154), p=0.001] and transesophageal echography by 78%, OR 0.228[CI 95 %(0.228-0.052), p=0.05].Population characteristics and outcomes ConclusionID consultation in the setting of SAB has been shown to increase compliance with IDSA guidelines and reduce 90-day mortality.Disclosures All Authors: No reported disclosures

Características clínicas y microbiológicas de infecciones del torrente sanguíneo en pacientes adultos neutropénicos

Bloodstream infections (BI) are relevant in neutropenic patients because they are associated with an increased number of complications and death. The objective was determinate the epidemiologic and microbiologic features of the BI in neutropenic patients with solid neoplasm (SN) and hematologic neoplasm (HN). Retrospective study in two third level hospitals between 2009 and 2016. They were included all the patients older than 18 years-old with active oncologic disease and neutropenia, who had BI. Patients with dermatologic cancer other than melanoma where excluded. A total of 143 BI in neutropenic were observed, of which 80.4% occurred in HN. Around 97.9% of the patients had a high-risk neutropenia without differences between both groups. The most frequent site of BI was primary bacteremia (46.9%) and catheter-associated infection (21%), without significant differences between the two groups. The gram negatives bacilli (GNB) predominated over the gram positive cocci (GPC) and they represented 74.1% of the isolated bacteria, being Escherichia coli the most frequent (32.8%). Among the gram positive cocci, Staphylococcus aureus (28.1%) was the most frequent isolated, followed by coagulase-negative Staphylococci (CNS). There were no differences in microbiological isolates between both groups. With regard to the antimicrobial susceptibility 67.5% of the CNS, 17.6% of the E. coli and 27.6% of the Klebsiella pneumoniae were multiresistant with no differences between both groups. Only 11.1% of S. aureus isolates were methicillin resistant. In conclusion BI of the neutropenic patients where most frequents within patients with HN, GNB were the main microbiological isolates. High mortality was observed in neutropenic patients with BI.

Akut Odağı Olmayan Ateş Tanısı Alan Çocuklarda Klinik ve Laboratuvar Bulguların Ciddi Bakteriyel Enfeksiyonu Öngörmedeki Değerlerinin Araştırılması

Objective: Fever is among most common causes of admission to hospital in childhood. In 20% of febrile infants and children, no focus can be identified by physical examination and this group is defined as “acute fever without a focus” (AFWF). Bacteremia (5%), and serious bacterial infection (15%) is determined in of children with AFWF. Clinical scales and laboratory tests are used to detect the risk of occult bacteremia and serious bacterial infection in children with AFWF This study aimed to determine relation between biochemical indicators and YALE Observation Scale, besides, rates of clinical scales and biochemical indicators predicting serious bacterial infections, in 3-36 months children with AFWF. Material and Methods: This study was performed prospectively, in 77 cases, between 3-36 months of AFWF. Low risk criteria was evaluated by performing YALE Observation Scale in children. Complete blood count, absolute neutrophil count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), interleukin 6, procalcitonin, urine analysis, chest x-ray, cerebrospinal fluid (CSF) examination; blood, urine and CSF cultures were obtained. Results: The mean age of the patients was 11.0 (4-36) months, 64.9% (n= 50) were boys. Most commonly AFWF recovered in patients (35.0%), and urinary tract infection was diagnosed (32.5%). Severe bacterial infection was determined in 44.2%. When patient groups with and without severe bacterial infection were compared, white blood count, ESH, CRP, and procalcitonin were significantly higher in severe bacterial infection (p&lt; 0.05). Erythrocyte sedimentation rate had highest specificity (87.5%) in discriminating between groups with and without severe bacterial infection. Conclusion: In conclusion, AFWF mostly recovered in children at 3-36 months, and urinary tract infection was common cause. White cell count, ESR, CRP and procalcitonin were found valuable in predicting serious bacterial infection. Further studies are needed to predict interleukin-6 value relevant to serious bacterial infection.

Binding of Kingella kingae RtxA Toxin Depends on Cell Surface Oligosaccharides, but Not on β2 Integrins.

The Gram-negative coccobacillus Kingella kingae is increasingly recognized as an important invasive pediatric pathogen that causes mostly bacteremia and skeletal system infections. K. kingae secretes an RtxA toxin that belongs to a broad family of the RTX (Repeats in ToXin) cytotoxins produced by bacterial pathogens. Recently, we demonstrated that membrane cholesterol facilitates interaction of RtxA with target cells, but other cell surface structures potentially involved in toxin binding to cells remain unknown. We show that deglycosylation of cell surface structures by glycosidase treatment, or inhibition of protein N- and O-glycosylation by chemical inhibitors substantially reduces RtxA binding to target cells. Consequently, the deglycosylated cells were more resistant to cytotoxic activity of RtxA. Moreover, experiments on cells expressing or lacking cell surface integrins of the β2 family revealed that, unlike some other cytotoxins of the RTX family, K. kingae RtxA does not bind target cells via the β2 integrins. Our results, hence, show that RtxA binds cell surface oligosaccharides present on all mammalian cells but not the leukocyte-restricted β2 integrins. This explains the previously observed interaction of the toxin with a broad range of cell types of various mammalian species and reveals that RtxA belongs to the group of broadly cytolytic RTX hemolysins.

Mycobacterium Mucogenicum Bacteremia and Nodular Soft Tissue Infection in a Person Who Uses Tap Water to Inject Drugs.

The ongoing North American epidemic of intravenous opioid and methamphetamine use increases the occurrence of bacteremia from environmental organisms. In this study, we report a case of Mycobacterium mucogenicum bacteremia and associated nodular soft tissue infection in a person who uses tap water to inject drugs.

The pathogenesis of cardiac microlesion formation during severe bacteremic infection.

The pathogenesis of cardiac microlesion formation during severe bacteremic infection.

A non-inferiority study comparing efficacy of preoperative prophylactic antibiotics for preventing infectious complications in patients with less severe burns

While international burn injury guidelines discourage prophylactic antibiotics on admission, current surgery guidelines focusing on antimicrobial prophylaxis place thermal injury under a general plastics procedure umbrella, and require significant evidential extrapolation. The purpose of this study was to determine if withholding systemic antibiotics in patients with <20% total body surface area (TBSA) burns without invasive wound infections and undergo wound excision is non-inferior to patients that receive preoperative antibiotics. Success was defined as lack of graft loss, bacteremia, or surgical site infection. One-thousand and eighty-three patients were screened and 100 patients undergoing 133 operations remained after exclusions. Seventy-four percent were male. Median age and %TBSA was 41 years (30, 55) and 5 (1.5, 8.3), respectively. We found no differences in demographics between patients that did and did not receive preoperative antibiotics. The success rates were 81.7% and 84.3%, respectively. There was one clinically significant bacteremia in each group. Withholding preoperative antibiotics was non-inferior with a percent difference of 2.6 (95% CI; −10.4, 15.6). Patients that did not receive antibiotics were no more likely to incur infection-related complications. In patients with <20% TBSA burns and without active wound infections, withholding preoperative systemic antibiotics will preserve unneeded antimicrobial exposure without increasing risk of infection-related complications.

Limited Clinical Utility of Follow-up Blood Cultures in Patients With Streptococcal Bacteremia: An Opportunity for Blood Culture Stewardship.

BackgroundThe value of positive follow-up blood cultures (FUBCs) in streptococcal bacteremia has not been well defined. Therefore, we explored the frequency of and risk factors for positive FUBC in a retrospective cohort of patients with streptococcal bacteremia.MethodsAdults ≥18 years of age, admitted with at least 1 positive blood culture for Streptococcus spp between 2013 and 2018 followed by at least 1 FUBC, were potentially eligible. Positive FUBCs were defined as cultures positive for the same streptococcal species drawn >24 hours after the index culture. We excluded patients with polymicrobial bacteremia. We compared the characteristics of patients with and without a positive FUBC.ResultsIn our single-center cohort, we identified 590 patients with streptococcal bacteremia, and 314 patients met inclusion criteria. Ten patients had FUBC with Streptococcus spp (3.2%), 4 (1.3%) had a contaminant identified, and 3 (1.0%) had a new pathogen isolated. Endocarditis (5 of 10 [50.0%] vs 35 of 304 [11.5%]), epidural abscess (2 of 10 [20%] vs 4 of 304 [1.3%]), and discitis or vertebral osteomyelitis (3 of 10 [30.0%] vs 14 of 304 [4.6%]) were associated with positive FUBC. Patients with positive FUBC had a longer median length of stay (12.9 vs 7.1 days, P = .004) and longer duration of antibiotic treatment (14.9 vs 43.2 days, P = .03).ConclusionsFollow-up blood cultures among patients with streptococcal BSI are rarely positive. Clinicians could consider limiting follow-up blood cultures in patients at low risk for deep-seated streptococcal infections, persistent bacteremia, or endovascular infection.