Outcome Of Bloodstream Infections Research Articles

Impact of Early Initiation of Appropriate Antibiotic Therapy on Outcome of Bloodstream Infections

Impact of Early Initiation of Appropriate Antibiotic Therapy on Outcome of Bloodstream Infections

Microbiological Profile and Susceptibility Pattern of Bacterial Blood Culture Isolates in COVID-19 Patients with Septicemia from a Designated COVID Hospital in Pune

In severe Coronavirus disease 2019 (COVID-19), bloodstream infections (BSIs) are an increasing cause of morbidity and mortality. In critically ill patients with COVID-19, we aimed to evaluate the prevalence, clinical profiles, and outcomes of BSIs. This single-center prospective investigation was conducted at a tertiary care hospital in Western India. All patients (>18 years of age) hospitalized in the intensive care unit (ICU) or ward with RT-PCR-confirmed COVID-19 were included. Demographic information, clinical proficiency, and antibiotic resistance patterns were assessed. Of the 550 patients admitted to the COVID ICU, subsequent BSIs occurred in 7.45% of patients. Gram-negative pathogens comprised a significant proportion of BSIs (53/73, 72.6%). The most frequent isolates were Klebsiella pneumoniae (22/73, 30.1%), Acinetobacter baumannii (11/73,15.06%), and Escherichia coli (7/23, 9.58%). In 57.8% of the cases, multidrug-resistant organisms (MDRO) were discovered. The Enterococcus and K. pneumoniae families comprise the majority of MDRO. Gram-negative bacteria (30.18% [16/53]) were resistant to carbapenems. Increased total leukocyte count, mechanical ventilation, and the presence of comorbidities were significantly associated with the incidence of BSIs. In COVID-19-linked BSIs, we discovered a high frequency of A. baumannii. Clinicians should be aware of potential BSIs in the presence of comorbidities, elevated leukocyte count, and mechanical ventilation. To improve the results, empirical antibiotics must be started promptly, and the situation must be de-escalated quickly. The most frequent isolates were A. baumannii and K. pneumoniae ([11/73, 15.06%] and [22/73, 30.1%], respectively). To reduce the incidence of MDRO, infection control procedures should be strictly followed in patients with multidrug resistance.

Gram-negative bacteremia, the risk factors, and outcome in children

We aimed to determine the epidemiology and resistance patterns of Gram-negative bacteria, the risk factors and outcome of bloodstream infection (BSI). In all, 412 episodes in children who were hospitalized with the diagnosis of bacteremia were analyzed. The most common microorganisms were Klebsiella spp. (43.9%), Escherichia coli (13.5 %) and Acinetobacter spp. (10.6 %). Among isolates, 41.2 % were multidrug-resistant, 13.5 % were extensively drug-resistant and 0.4 % were pan-drug-resistant. Carbapenem resistance was revealed in 27.6 % of isolates. Carbapenem and colistin resistance increased over the years. The most common risk factors were the presence of a central-venous catheter and pediatric intensive care unit admission. Clinical response and infection-related mortality were significantly different in cases infected with carbapenem-resistant gram-negative (CRGN) vs carbapenem-susceptible gram-negative bacteria. The increase in multi-resistant Klebsiella spp. seems to be the biggest obstacles in fight against nosocomial infections. The increasing number of CRGN infections over the years affects both the clinical response and mortality rate of BSI.

Risk factors and outcomes of bloodstream infection from a urinary source in kidney transplant recipients.

Bacteriuria is common among kidney transplant recipients (KTR). Risk factors and outcomes associated with bloodstream infection due to a urinary source (BSIU) in KTR are poorly understood. This single center case-control study from 2010 to 2022 compared KTR with BSIU to those with bacteria without bloodstream infection (BU). Multivariable logistic regression identified BSIU risk factors, and Cox models assessed its impact on graft failure. Among 3435 patients, who underwent kidney transplantation at Emory Hospital, 757 (22%) developed bacteriuria, among whom 142 (18.8%) were BSIU. Male sex, presence of Escherichia coli, Klebsiella pneumoniae, or Pseudomonas species in urine culture, urethral stricture, neuromuscular bladder disorder, and history of diabetes-induced renal failure were independently associated with increased odds of BSIU (Male sex: aOR 2.29, 95% CI 1.52, 3.47, E. coli: aOR 5.14, 95% CI 3.02, 9.13; K. pneumoniae aOR 3.19, 95% CI 1.65, 6.27, Pseudomonas spp aOR 3.06, 95% CI 1.25, 7.18; urethral stricture: 4.10, 95% CI 1.63, 10.3, neuromuscular bladder disorder aOR 1.98, 95% CI 1.09, 3.53, diabetes: aOR 1.64, 95% CI 1.08, 2.49). BSIU was associated with increased hazard of graft failure (HR 1.52, 95% CI 1.05, 2.20). Close monitoring is warranted for male KTR with bacteriuria, those with urine cultures positive for Pseudomonas spp, K. pneumoniae, or E. coli, as well as KTR with a history of diabetes-induced renal failure, urethral stricture, or neuromuscular bladder disorder due to their risk for developing BSIU. Future research should explore strategies to mitigate BSIU risk in these high-risk KTR and reduce the associated risk of long-term graft failure.

Bacteriological Profile and Antibiogram of Aerobic Blood Culture Isolates among Suspected Blood Stream Infections: A Cross-sectional Study

Introduction: Bloodstream Infections (BSIs) are important causes of morbidity and mortality worldwide. Blood culture is the most important diagnostic tool for BSI. The epidemiology and outcome of BSI are constantly changing due to increasing antimicrobial resistance, changing patterns of antibiotic drug usage, and the increased use of transient or permanent medical devices. Thus, regular monitoring of the bacterial aetiology of BSI and their antibiograms is necessary. Aim: To determine the bacteriological profile and antibiotic susceptibility patterns among suspected BSI patients. Materials and Methods: A hospital-based cross-sectional study was carried out in the Department of Microbiology, Jawaharlal Nehru Institute of Medical Sciences (JNIMS), Imphal, Manipur, India, from September 2018 to August 2020. A total of 481 suspected BSI patients were included in the study. The blood culture samples were collected under aseptic conditions and cultured for seven days. The isolates were identified using conventional biochemical tests, and the antibiotic susceptibility pattern was determined by the Kirby-Bauer disk diffusion method and the epsilometer test (E-test). Methicillin resistance among the staphylococcal isolates was detected using the cefoxitin disk diffusion method. Data analysis was performed using EpiInfoTM version 7.0, and the Chi-square test was used as a statistical test. Results: A total of 150 (31.2%) blood samples were culture positive out of the 481 samples processed from suspected BSI patients. The predominant isolates were gram-positive, accounting for 113/150 (75.3%), while gram-negatives accounted for 37/150 (24.7%). Staphylococcus aureus, Pseudomonas aeruginosa, and Coagulase Negative Staphylococci (CoNS) were the primary pathogens isolated. Methicillin resistance was detected in 59 (54.6%) of the staphylococcal isolates {52 (54.7%) were Methicillin Resistant S. aureus (MRSA), and out of the 13 CoNS isolates, 7 (53.9%) were Methicillin Resistant CoNS (MRCoNS)}. The most susceptible drugs for gram-positives were vancomycin and linezolid, while aminoglycosides and imipenem were the most susceptible drugs for gram-negatives. Conclusion: The study highlighted the prevalence and pattern of aerobic bacterial isolates in BSI cases at JNIMS Hospital, as well as, the antibiotic susceptibility patterns of the isolates. Regular epidemiological studies of BSIs, regarding the pathogens and their antibiotic susceptibility patterns, are necessary to guide clinicians in choosing appropriate empirical therapy and to update the hospital antibiotic policy from time to time. This promotes rational antibiotic use and reduces resistance among bacteria.

176. Impact of Rapid Blood Culture Identification Panel on Antibiotic Treatment and Clinical Outcomes in Bloodstream Infections, Particularly Those Associated with Multidrug-resistant Microorganisms

Abstract Background The FilmArray Blood Culture Identification (BCID) panel (BioFire Diagnostics, USA) can detect 19 bacteria, five Candida spp., and three antimicrobial resistance determinants (mecA, vanA/B, and bla-KPC). This study evaluated the impact of BCID on the time to effective antibiotic administration and clinical outcomes in bloodstream infections, particularly carbapenem-resistant Enterobacterales (CRE), vancomycin-resistant enterococci (VRE) and carbapenem-resistant Acinetobacter baumannii (CRAB) bacteremia. Methods The clinical outcomes and time to effective antibiotic administration for bloodstream infections were retrospectively compared between patients who had undergone BCID testing and conventional culture method (control group). Further, we compared the 30-day mortality and time to effective antibiotic administration between BCID and conventional methods in CRE, CRAB, and VRE bacteremia. Results We compared 144 and 214 patients who had undergone BCID testing and the conventional culture method, respectively. The median time until the administration of effective antibiotics (3 h for both BCID and conventional culture, P = 0.789), appropriate antibiotics (BCID: 37 h vs. conventional culture: 44 h, P = 0.727), and 30-day mortality (BCID: 9.7% vs. conventional culture: 10.7%, P = 0.755) did not differ significantly between the groups. Multivariable analysis revealed that BCID was not associated with 30-day mortality after adjusting for Pitt bacteremia and Charlson comorbidity index (adjusted OR: 0.833, CI: 0.398–1.743) (Table 1). BCID did not reduce the risk of 30-day mortality in any subgroup: patients with ICU stay, hematologic department admissions, hospital-acquired infections, gram-positive and gram-negative bacteremia. Time to effective antibiotic administration was significantly reduced on using BCID in patients with CRE and VRE bacteremia, while no difference was observed in patients with CRAB bacteremia (Table 2). Conclusion BCID did not improve the clinical outcomes of overall bloodstream infections. However, it contributed to the early administration of effective antibiotics in patients with CRE and VRE bacteremia. BCID may be useful in selected patients in whom infection with multidrug-resistant microorganism is suspected. Disclosures All Authors: No reported disclosures

The Impact of the Rapid Blood Culture Identification Panel on Antibiotic Treatment and Clinical Outcomes in Bloodstream Infections, Particularly Those Associated with Multidrug-Resistant Micro-Organisms

We evaluated the impact of the FilmArray blood culture identification (BCID) panel on the time taken to administer effective antibiotics and the clinical outcomes of bloodstream infections. We retrospectively screened patients with bloodstream infections who underwent BCID testing and compared them to a historical control group that received conventional culture testing. A total of 144 and 214 patients who underwent BCID and conventional cultures, respectively, were compared. The 30-day mortality (BCID: 9.7% vs. conventional method: 10.7%, p = 0.755), time to effective antibiotic administration (3 h for both BCID and conventional method, p = 0.789), and time to appropriate antibiotic administration did not differ significantly between the groups. BCID was not significantly associated with 30-day mortality after adjusting for the Pitt bacteremia score and the Charlson comorbidity index (adjusted OR = 0.833, CI; 0.398–1.743). Compared with conventional methods, BCID reduced the time to administration of effective antibiotics in cases of carbapenem-resistant Enterobacterales (CRE) (39 h vs. 93 h, p = 0.012) and vancomycin-resistant enterococci (VRE) (50 h vs. 92 h, p < 0.001) bacteremia. BCID did not affect the clinical outcomes of overall bloodstream infections; however, it contributed to the early administration of effective antibiotics in cases of CRE and VRE bacteremia.

Incidence, Etiology, Risk Factors, and Outcomes of Bloodstream Infection after a Second Hematopoietic Stem Cell Transplantation.

Objective Infections after a second hematopoietic stem cell transplantation (HSCT) occur commonly and are associated with high mortality. However, studies on bloodstream infection (BSI) after a second HSCT are lacking. We therefore evaluated the details of BSI after a second HSCT. Methods We retrospectively evaluated the incidence, etiology, risk factors, and outcomes of BSI after a second HSCT. Patients Fifty-two adult patients with hematological malignancies who underwent allogeneic HSCT, including cord blood transplantation (CBT; n=33), as the second transplantation were enrolled. The second transplantation was limited to allogeneic HSCT. Patients who underwent HSCT for graft failure were excluded. Results The median HSCT interval was 438 (range: 39-3893) days. Overall, 31 (59.6%) patients received autologous HSCT as the first HSCT. The cumulative incidence of BSI was 40.4% at 100 days after the second HSCT, with Gram-positive bacteria accounting for the majority (30.8%) of pathogens. Overall, 92.0% of BSIs occurred during the pre-engraftment period, and Enterococcus faecium accounted for 29.6% of pathogens. On a multivariate analysis, CBT was most closely associated with pre-engraftment BSI after the second HSCT (hazard ratio: 3.43, 95% confidence interval: 1.05-11.23, P=0.042). The 1-year survival rate after the second HSCT was lower in patients with BSI than in patients without BSI (P=0.10). Conclusion BSI is common after a second HSCT, especially with CBT. During the pre-engraftment period, BSI caused by pathogens such as E. faecium should be anticipated and appropriately treated to improve transplant outcomes.

Incidence and Outcomes of Bloodstream Infection After Arterial Aneurysm Repair: Findings From a Population-Based Study.

Limited research has focused on bloodstream infection (BSI) in patients with arterial grafts. This study aims to describe the incidence and outcomes of BSI after arterial aneurysm repair in a population-based cohort. The expanded Rochester Epidemiology Project (e-REP) was used to analyze aneurysm repairs in adults (aged ≥18 years) residing in 8 counties in southern Minnesota from January 2010 to December 2020. Electronic records were reviewed for the first episode of BSI following aneurysm repair. BSI patients were assessed for vascular graft infection (VGI) and followed for all-cause mortality. During the study, 643 patients had 706 aneurysm repairs: 416 endovascular repairs (EVARs) and 290 open surgical repairs (OSRs). Forty-two patients developed BSI during follow-up. The 5-year cumulative incidence of BSI was 4.7% (95% confidence interval [CI], 3.0%-6.4%), with rates of 4.0% (95% CI, 1.8%-6.2%) in the EVAR group and 5.8% (95% CI, 2.9%-8.6%) in the OSR group (P = .052). Thirty-nine (92.9%) BSI cases were monomicrobial, 33 of which were evaluated for VGI. VGI was diagnosed in 30.3% (10/33), accounting for 50.0% (8/16) of gram-positive BSI cases compared to 11.8% (2/17) of gram-negative BSI cases (P = .017). The 1-, 3-, and 5-year cumulative post-BSI all-cause mortality rates were 22.2% (95% CI, 8.3%-34.0%), 55.8% (95% CI, 32.1%-71.2%), and 76.8% (95% CI, 44.3%-90.3%), respectively. The incidence of BSI following aneurysm repair was overall low. VGI was more common with gram-positive compared to gram-negative BSI. All-cause mortality following BSI was high, which may be attributed to advanced age and significant comorbidities in our cohort.

Clinical Outcomes of Third-Generation Cephalosporin Definitive Therapy for Bloodstream Infections Due to Enterobacterales with Potential AmpC Induction: A Single-Center Retrospective Study.

The recommended therapy for severe infections caused by AmpC-inducible Enterobacterales (AmpC-E) typically involves cefepime or carbapenems. In an era of emerging resistance to these antimicrobials, we aim to assess the impact of third-generation cephalosporins (3GCs) vs. alternative antibiotics on clinical outcomes in bloodstream infections (BSIs) due to AmpC-E. We retrospectively included hospitalized adult patients with BSIs caused by 3GC-susceptible AmpC-E between 2012 and 2022, comparing the outcomes of 3GC and non-3GC definitive therapies. The primary outcome was overall treatment failure (OTF), encompassing 90-day all-cause mortality, 90-day reinfection, and 90-day readmission. Secondary outcomes comprised components of the OTF, in-hospital all-cause mortality, and length-of-stay. Within a total cohort of 353 patients, OTF occurred in 46.5% and 41.5% in the 3GC- and non-3GC-therapy groups, respectively (p = 0.36). The 3GC-therapy group exhibited a longer length-of-stay (38 vs. 21 days, p = 0.0003) and higher in-hospital mortality (23.3% vs. 13.4%, p = 0.019). However, the 90-day mortality, 90-day reinfection, and 90-day readmission were comparable between the therapy groups. Subgroup analyses involving high-risk AmpC-E and 3GC vs. standard-of-care yielded similar conclusions. Overall, our findings suggest that 3GC definitive therapy may not result in poorer clinical outcomes for the treatment of BSIs caused by AmpC-E.

Understanding the impact of antimicrobial resistance on outcomes of bloodstream infections in low- and middle-income countries.

Marlieke de Kraker discusses a systematic review and meta-analysis reporting the magnitude and consequences of bloodstream infections in low- and middle-income countries.

Bloodstream infection burden among cancer clinic patients with PICC Lines: A prospective, observational study

Background: Oncology patients are at high risk for bloodstream infection (BSI) due to immunosuppression and frequent use of central venous catheters. Surveillance in this population is largely relegated to inpatient settings and limited data are available describing community burden. We evaluated rates of BSI, clinic or emergency department (ED) visits, and hospitalizations in a large cohort of oncology outpatients with peripherally inserted central catheters (PICCs). Methods: In this prospective, observational study, we followed a convenience sample of adults (age>18) with PICCs at a large academic outpatient oncology clinic for 35 months between July 2015 and November 2018. We assessed demographics, malignancy type, PICC insertion and removal dates, history of prior PICC, and line duration. Outcomes included BSI events (defined as >1 positive blood cultures or >2 positive blood cultures if coagulase-negative Staphylococcus), ED visits (without hospitalization), and unplanned hospitalizations (excluding scheduled chemotherapy hospitalizations). We used χ2 analyses to compare the frequency of categorical outcomes, and we used unpaired t tests to assess differences in means of continuous variable in hematologic versus solid-tumor malignancy patients. We used generalized linear mixed-effects models to assess differences in BSI (clustered by patient) separately for gram-positive and gram-negative BSI outcomes. Results: Among 478 patients with 658 unique PICC lines and 64,190 line days, 271 patients (413 lines) had hematologic malignancy and 207 patients (232 lines) had solid-tumor malignancy. Cohort characteristics and outcomes stratified by malignancy type are shown in Table 1. Compared to those with hematologic malignancy, solid-tumor patients were older, had 47% fewer clinic visits, and had 32% lower frequency of prior PICC lines. Overall, there were 75 BSI events (12%; 1.2 per 1,000 catheter days). We detected no significant difference in BSI rates when comparing solid-tumor versus hematologic malignancies (P = 0.20); BSIs with gram-positive pathogen were 69% higher in patients with solid tumors. Gram-negative BSIs were 41% higher in patients with hematologic malignancy. Solid-tumor malignancy was associated with 4.5-fold higher odds of developing BSI with gram-positive pathogen (OR, 4.48; 95% CI, 1.60–12.60; P = .005) compared to those with hematologic malignancy, after adjusting for age, sex, history of prior PICC, and line duration. Differences in gram-negative BSI were not significant on multivariate analysis. Conclusions: The burden of all-cause BSIs in cancer clinic adults with PICC lines was 12% or 1.2 per 1,000 catheter days, as high as nationally reported inpatient BSI rates. Higher risk of gram-positive BSIs in solid-tumor patients suggests the need for targeted infection prevention activities in this population, such as improvements in central-line monitoring, outpatient care, and maintenance of lines and/or dressings, as well as chlorhexidine bathing to reduce skin bioburden.Disclosures: None

Bloodstream Infection and Gram-Negative Resistance: The Role for Newer Antibiotics.

Gram-negative resistance remains a major challenge. Rates of in vitro resistance to commonly utilized antibiotics have skyrocketed over the last decade. Clinicians now encounter multidrug-resistant organisms routinely. Fortunately, newer agents, such as ceftazidime-avibactam, ceftolozone-tazobactam, meropenem-vaborbactam, and cefiderocol, have been developed and are now available for use against these pathogens. Clinical trials with these novel therapies have focused on multiple infection types ranging from complicated urinary tract infections to nosocomial pneumonia. Nonetheless, there remains little information about the efficacy of these drugs for bacteremia. To better appreciate the types and limitations of the evidence supporting the role for these unique molecules in bloodstream infection, one requires an appreciation of the initial clinical trials supporting the regulatory approval of these antibiotics. Furthermore, physicians must understand the subsequent case series and reports specifically focusing on outcomes for patients with bacteremia treated with these drugs. Despite the limitations of the data and reports relating to treatment for bacteremia with these antibiotics, each agent appears to be efficacious and can provide good outcomes in bloodstream infections due to resistant pathogens.

Epidemiology, Resistance Profiles, and Outcomes of Bloodstream Infections in Community-Onset Sepsis in the United States.

To describe frequency of positive blood cultures, patterns of pathogens' characteristics and their resistance profile in patients with blood cultures drawn due to a presumed diagnosis of community-onset sepsis, and to examine the association between blood culture-positive pathogens and hospital mortality. Retrospective cohort study. Two hundred one U.S. hospitals from 2016 to 2020 using the Premier Healthcare Database. Adult patients presenting with community-onset sepsis who had blood cultures collected within 2 days of hospital admission. We defined sepsis using the U.S. Centers for Disease Control Adult Sepsis Event Surveillance criteria. None. We identified 147,061 patients with community-onset sepsis. The number of blood culture-positive sepsis episodes was 21,167 (14%) and the number of nonblood culture-positive sepsis episodes was 20,326 (14%). Among patients with blood culture-positive sepsis, Gram-negative rods were isolated in 55% of patients, Gram-positive cocci were isolated in 47%. Of those, methicillin-resistant Staphylococcus aureus (MRSA) was 11%, ceftriaxone-resistant Enterobacterales /extended-spectrum β-lactamase was 7%, and carbapenem-resistant Enterobacterales was 1.3%. The crude in-hospital mortality was 17% for culture-negative sepsis, 13% for nonblood culture-positive sepsis, and 17% for blood culture-positive sepsis. In multilevel logistic regression models, compared with culture-negative sepsis, blood culture-positive sepsis (adjusted odds ratio [aOR], 0.89; 95% CI, 0.85-0.94) and nonblood culture-positive sepsis (aOR, 0.82; 95% CI, 0.78-0.87) were associated with lower odds of in-hospital mortality. Acinetobacter species, Pseudomonas aeruginosa , methicillin-sensitive Staphylococcus aureus , and MRSA were associated with higher in-hospital mortality, whereas Escherichia coli , Klebsiella species, Proteus species, and Streptococcus species were associated with lower in-hospital mortality. In patients hospitalized with community-onset sepsis, the prevalence of blood culture-positive sepsis was 14%. Among positive blood culture sepsis resistant organisms were infrequent. Compared with culture-negative sepsis, blood culture-positive sepsis and nonblood culture-positive sepsis were associated with lower in-hospital mortality.

Incidence, Risk Factors and Outcome of Bloodstream Infections in Patients After Hematopoietic Stem-Cell Transplantation: A Single Center Study.

The bloodstream infections (BSIs) are among the most common infectious complications after hematopoietic stem-cell transplantation (HSCT), often associated with high mortality rates. The aim of this study was to evaluate the incidence, risk factors and outcome of BSIs in HSCT recipients from the Transplantation Center of the University Hospital in Varna, Bulgaria during the period January 2019-December 2021. The role of patient- and transplantation-related variables was studied as potential risk factors for BSIs and survival after HSCT. Seventy-four patients were included in the study. The cumulative incidence of BSIs was 35%. The mean period of BSI onset after HSCT was 8days. The Gram-positive bacteria were more commonly isolated as causative agents (52.3%). The mortality rate 30days after the diagnosis of BSI was 23%. Fecal colonization with multidrug-resistant (MDR) bacteria (p = 0.005) and pre-transplant BSI (p = 0.05) were associated with significantly increased risk for post-HSCT BSIs. The overall 4-month survival was 86.5%. A statistical significance was found between the type of the underlying disease (acute leukemia and lymphoma, p = 0.043), previous HSCT (p = 0.001) and 4-month survival. This study confirms that the fecal colonization with MDR bacteria before transplantation and pre-transplant BSIs are independent risk factors for the occurrence of BSI in the early period after HSCT. Pre- and posttransplant monitoring of the patient fecal colonization status with MDR organisms, could contribute considerably to the prevention and successful management of the infectious complications in patients after HSCT.

Impact of Adding a Rapid PCR-Based Blood Culture Identification Panel to the Antimicrobial Stewardship Program of Patients with Febrile Neutropenia in a Peruvian Referral Hospital.

The addition of Biofire® FilmArray® Blood Culture Identification panel 2 (BCID2) to the antimicrobial stewardship program (ASP) could improve outcomes in bloodstream infections (BSI) of patients with febrile neutropenia (FN). A pre- and post-quasi-experimental single-center study was conducted at a reference hospital in Peru. Three groups were considered: patients with BSI before ASP intervention (control group), patients with BSI after ASP intervention (group 1), and patients with BSI after ASP intervention plus BCID2 PCR Panel implementation (group 2). Overall, 93 patients were identified (32 control, 30 group 1, 31 group 2). The median time to effective therapy was significantly shorter in group 2 compared to group 1 and control group, respectively (3.75 vs. 10 h, p = 0.004; 3.75 vs. 19 h, p < 0.001). No significant differences in terms of relapse of bacteremia, in-hospital mortality (all cause), and 30-day-all-cause hospital readmission between the three study periods were found. The appropriateness of empirical antimicrobial use, adding or change, and the following de-escalation or discontinuation was significant when the two intervention periods were compared with the control group (p < 0.001). In addition to the lack of local studies documenting the microbiological profile of FN episodes, adding syndromic panels-based testing could allow for the consolidation of ASP strategies.

Phenotypic and genotypic antibiotic susceptibility profiles of Gram-negative bacteria isolated from bloodstream infections at a referral hospital, Lusaka, Zambia.

Bloodstream infections (BSI) caused by antimicrobial-resistant (AMR) Gram-negative bacteria (GNB) are a significant cause of morbidity and mortality. Third-generation cephalosporins (3GCs) have been used as empiric treatment for BSI and other invasive infections for years; however, their overuse could promote the emergence of extended-spectrum beta-lactamases (ESBLs). Thus, this study aimed to determine the epidemiological, clinical and microbiological features and the effects of antimicrobial resistance on the outcomes of BSIs at a referral hospital in Lusaka, Zambia. This was a six-month prospective facility-based study undertaken at a referral hospital in Lusaka, Zambia. As part of the routine diagnosis and patient care, blood samples for bacteriological culture were collected from patients presenting with fever and processed for pathogen identification and antimicrobial susceptibility testing using the VITEK 2 Compact instrument. ESBLs and plasmid-mediated quinolone resistance (PMQR) associated genes were determined using the polymerase chain reaction method. Patient information was collected using a structured data collection sheet and entered in CSpro 7.6. Data were analysed in WHOnet and STATA version 14. A total of 88 GNB were isolated, of which 76% were Enterobacterales, 14% Acinetobacter baumannii and 8% Pseudomonas aeruginosa. Resistance to third and fourth-generation cephalosporins was 75% and 32%, respectively. Noteworthy was the high prevalence (68%) of inappropriate empirical treatment, carbapenem resistance (7%), multi-drug resistance (83%) and ESBL-producers (76%). In comparison to E. coli as a causative agent of BSI, the odds of death were significantly higher among patients infected with Acinetobacter baumannii (OR = 3.8). The odds of death were also higher in patients that received 3GCs as empiric treatment than in those that received 4GCs or other (none cephalosporin) treatment options. Structured surveillance, yearly antibiogram updates, improved infection control and a well functional antimicrobial stewardship (AMS) program, are of utmost importance in improving appropriate antimicrobial treatment selection and favourable patient outcomes.

1833. Evaluating the Impact of Reported Beta-Lactam Allergies on Clinical Outcomes in Gram-Negative Bloodstream Infections: A Retrospective Cohort Study

Abstract Background Approximately 15% of hospitalized patients are labeled as beta-lactam (BL) allergic. Despite this, it is estimated that &amp;gt; 90% of patients do not have clinically significant hypersensitivity reactions and are BL-tolerant. The BL allergy label is associated with a host of downstream consequences, including receipt of suboptimal antibiotic therapy, healthcare-associated infections, and bacterial resistance. There are limited data investigating the impact of this allergy label on clinical outcomes in bloodstream infections caused by Gram-negative pathogens (GN-BSI). Methods This was a retrospective, single center, cohort study evaluating the impact of BL allergies on clinical outcomes in patients with GN-BSI from January 2017 to August 2021. Adult inpatients with index blood cultures positive for Pseudomonas species or Enterobacterales who received intravenous antibiotics with Gram-negative activity were included. The primary endpoint was time to effective therapy (defined as treatment with in vitro activity against a causative pathogen, as determined by phenotypic susceptibilities) and the key secondary endpoint was 30-day all-cause mortality. Results Overall, 120 patients were included, representing 30 BL-allergic (BL-A) and 90 BL-non-allergic (BL-NA) patients. Blood cultures positive for Pseudomonas species or Enterobacterales were evenly distributed (Table 1). Among Enterobacterales, Escherichia coli was implicated in 25% of cases overall. The most common source of infection was intra-abdominal infection. Across groups, median quick Pitt Bacteremia Score was 1 (IQR 0-2). Infectious Diseases was consulted in 37% of BL-A patients vs. 29% of BL-NA patients. Of BL allergies reported, 86% were classified as likely immunoglobulin E (IgE) mediated reactions. Allergy was not consulted in any of these cases. Median time to effective therapy was 162 minutes (IQR 20-824 minutes) vs. 103 minutes (IQR 27-775 minutes) in the BL-A and BL-NA groups, respectively. Thirty-day mortality occurred in 31% of BL-A and 21% of BL-NA patients. Conclusion Increased time to effective therapy and mortality rates were observed among patients with reported BL allergies. These findings highlight the importance of allergy clarification in antibiotic stewardship. Disclosures Kathleen Degnan, MD, Gilead: Grant/Research Support.

Clinical Characteristics, Microbiology, and Risk Factors for Mortality of Pre-Engraftment and Post-Engraftment Bloodstream Infection in Hematopoietic Stem Cell Transplantation Recipients.

Bloodstream infection (BSI) is a common and serious complication that may lead to high mortality during the different phases after hematopoietic stem cell transplant (HSCT). We investigated BSI in patients undergoing HSCT to provide an appropriate clinical anti-infection experience and improve the prognosis of recipients with BSI after HSCT. A total of 105 patients with BSI after HSCT at our center from January 2015 to June 2020 were included in this retrospective study. We analyzed the clinical and microbiological data, and the risk factors for mortality at 3 months after BSI. Of the 1141 HSCT recipients, 105 (9.2%) patients presented with 122 episodes of BSI, of which we isolated 85 (65.9%) gram-negative bacteria, 32 (24.8%) gram-positive bacteria and 12 (9.3%) fungi. Multidrug-resistant bacteria (MDR) were more than 70% of all pathogens and carbapenem-resistant organisms (CRO) were 25.6%. There were 55 episodes of BSI in the pre-engraftment phase and 67 episodes in the post-engraftment phase. The mortality of post-engraftment BSI was significantly higher than that of pre-engraftment (56.7% vs 32.7%, p = 0.005). Through multivariate analysis, the independent risk factors for all-cause mortality at 3 months after BSI were higher levels of procalcitonin (PCT), failure to cover appropriate antibiotics timely, and CRO BSI in pre-engraftment period or multidrug-resistant gram-negative bacteria (MDRGNB) BSI in post-engraftment period. Although the incidence of BSI was lower after HSCT, MDR-dominated BSI had a high mortality rate. Rapid identification of infection or pathogens' classification with various testing methods and the more sensible and timely antibiotic cover are critical to the outcome of BSI after HSCT.

Interspecies differences in clinical characteristics and risk factors for third-generation cephalosporin resistance between Escherichia coli and Klebsiella pneumoniae bloodstream infection in patients with liver cirrhosis.

This retrospective study aimed to clarify the interspecies differences in the clinical characteristics and risk factors of bloodstream infection (BSI) due to third-generation cephalosporin-resistant (3GC-R) Escherichia coli (EC) and Klebsiella pneumoniae (KP) in patients with liver cirrhosis (LC). KP BSI had more comorbidities and higher treatment failure rate than EC BSI. Non-alcoholic LC was a risk factor for treatment failure in EC, whereas it was not associated with KP. Risk factors for BSI due to 3GC-R strain were nosocomial infection in EC, and β-lactam/fluoroquinolone treatment ≤ 30days in KP. These results could help predict outcomes of BSI and improve clinical practice.