Maltophilia Bloodstream Infections Research Articles

Stenotrophomonas maltophilia Bloodstream Infection Outbreak in an Acute Care Hospital — Alameda County, California 2022–2023

Background: Stenotrophomonas maltophilia is an opportunistic pathogen found in healthcare settings. During April–September 2022, nine S. maltophilia bloodstream infections (BSIs) were identified among intensive care unit (ICU) patients at a hospital in Alameda County, California. Whole genome sequencing found isolates to be highly related. Despite implementation of infection prevention and control (IPC) interventions, four additional S. maltophilia BSIs were identified during June–September 2023. We investigated to identify risk factors for infection and stop transmission. Methods: We conducted a matched case-control study. A case was defined as S. maltophilia isolated from a blood culture from an ICU patient with a fever during April 2022–September 2023; control-patient subjects were patients admitted to the ICU during the same period with hospital stay greater than or equal to their matched case. Three control subjects were matched to each case. We extracted information on risk factors for infection from medical charts and observed IPC practices in hospital locations of interest. We collected environmental samples from the ICU, radiology unit, and emergency department. Results: Among 13 cases and 39 control subjects, patients exposed to iodinated contrast Omnipaque-300 (odds ratio [OR]: 5.7; 95% CI: 1.2–28.0), injectable propofol (OR: 12.2; 95% CI: 1.5–101.4), or fentanyl (OR: 9.2; 95% CI: 1.8–Inf.) were more likely to have a S. maltophilia BSI, compared with control-subjects. IPC deficiencies included improper cleaning and storage of medical equipment, including the contrast injection system, and patient care supplies. The outbreak strain of S. maltophilia was not isolated from environmental samples. Conclusions: Although a point-source was not identified, S. maltophilia was likely transmitted through improper IPC practices involving injectable contrast or anesthesia. Recommendations on proper cleaning and disinfection of the contrast injection system and proper storage, preparation, and administration of medications were made to reduce risk for contamination.

Evaluation of Stenotrophomonas Maltophilia Bloodstream Infections in a Tertiary Pediatric Cardiovascular Surgery Intensive Care Unit in Turkey

Background: Stenotrophomonas maltophilia poses a significant challenge as a drug-resistant opportunistic bacterium, particularly in ICU settings. However, its impact on pediatric ICU patients, especially those undergoing cardiovascular surgery, are scarce. Therefore, we aimed to analyze the factors behind S. maltophilia bloodstream infections (BSI) in our tertiary pediatric cardiovascular surgery ICU by evaluating the 2-year data. Methods: In this retrospective study, we analyzed data of 11 (mean age 20.3±17.6 months) and 18 cases (mean age 22.4±18.5 months) diagnosed with S. maltophilia BSI out of 635 and 685 children who underwent cardiovascular surgery from March 2021 to February 2022, and March 2022 to February 2023, respectively. Factors including age, gender, cardiac pathologies, surgical risk scores, duration of extracorporeal membrane oxygenation (ECMO) and mechanical ventilation, length of ICU stay, and use of broad-spectrum antibiotics were compared. Results: The incidence of S. maltophilia BSI increased by 50.5% in 2022-2023 compared to the previous year. While no significant differences were noted in age, gender, or surgical frequency, notable distinctions emerged in ECMO and mechanical ventilation durations, ICU length of stay, and broad-spectrum antibiotic usage (p values<0.05). Conclusion: Prolonged ECMO and mechanical ventilation, along with extended ICU stays and broad-spectrum antibiotic administration following highrisk cardiac surgeries, emerged as significant contributors to S. maltophilia BSI in our ICU. This underscores the necessity for a comprehensive approach encompassing infection control protocols, prudent antimicrobial utilization, and strategies to minimize invasive procedures. Such a multifaceted approach is paramount in mitigating the prevalence of S. maltophilia BSI, especially in high-risk ICU environments.

Validation of a Stenotrophomonas maltophilia bloodstream infection prediction score in the hematologic malignancy population

Stenotrophomonas maltophilia (SM) bloodstream infections (BSIs) contribute to significant mortality in hematologic malignancy (HM) and hematopoietic stem cell transplantation (HSCT) patients. A risk score to predict SM BSI could reduce time to appropriate antimicrobial therapy (TTAT) and improve patient outcomes. A single center cohort study of hospitalized adults with HM/HSCT was conducted. Patients had ≥ 1 blood culture with a Gram-negative (GN) organism. A StenoSCORE was calculated for each patient. The StenoSCORE2 was developed using risk factors for SM BSI identified via logistic regression. Receiver operating characteristic (ROC) curves were plotted. Sensitivity and specificity for the StenoSCORE and StenoSCORE2 were calculated. Thirty-six SM patients and 534 non-SM patients were assessed. A StenoSCORE ≥ 33 points was 80% sensitive, 68% specific, and accurately classified 69% of GN BSIs. StenoSCORE2 variables included acute leukemia, prolonged neutropenia, mucositis, ICU admission, recent meropenem and/or cefepime exposure. The StenoSCORE2 performed better than the StenoSCORE (ROC AUC 0.84 vs. 0.77). A StenoSCORE2 ≥ 4 points was 86% sensitive, 76% specific, and accurately classified 77% of GN BSIs. TTAT was significantly longer for patients with SM BSI compared with non-SM BSI (45.16 h vs. 0.57 h; p < 0.0001). In-hospital and 28-day mortality were significantly higher for patients with SM BSI compared to non-SM BSI (58.3% vs. 18.5% and 66.7% vs. 26.4%; p-value < 0.0001). The StenoSCORE and StenoSCORE2 performed well in predicting SM BSIs in patients with HM/HSCT and GN BSI. Clinical studies evaluating whether StenoSCORE and/or StenoSCORE2 implementation improves TTAT and clinical outcomes are warranted.

Antibiotic utilization trends in Veterans Affairs patients with Stenotrophomonas maltophilia bloodstream infections.

Stenotrophomonas maltophilia is a multidrug-resistant gram-negative bacillus that can cause serious infections but has limited treatment options. This study aims to establish trends in the treatment of S. maltophilia bloodstream infections (BSI) across the United States in Department of Veterans Affairs (VA) facilities. Data was evaluated over a 10-year timeframe (2012 to 2021) in this retrospective cohort study. Veterans with ≥ 1 blood culture with S. maltophilia within a VA medical encounter were included. Microbiology, pharmacy, and patient information were collected through national VA data sources and chart review. Descriptive statistics and Poisson regression were used to summarize patient demographics, facility characteristics, microbiologic data, and treatment trends. A total of 374 blood cultures positive for S. maltophilia were identified across 75 VA facilities. Of 282 unique patients with BSI, the majority were male (93.6%), white (67.4%), with a mean age of 64 ± 13.1 years. Of those patients, 78% received treatment, 12.8% had a polymicrobial blood culture, and 5.3% had a documented sulfa allergy. Susceptibility results were most reported for trimethoprim-sulfamethoxazole (TMP-SMX), levofloxacin, and ceftazidime, with 4.5%, 4.3%, and 44.4% resistant isolates, respectively. Antibiotics most prescribed included TMP-SMX (41.5%) and levofloxacin (39.4%), followed by ciprofloxacin (13.8%) and ceftazidime (12.4%). Combination therapy was prescribed in 33% of patients. No significant trends were found with antibiotic utilization over time. TMP-SMX and levofloxacin were the most prescribed antibiotics for S. maltophilia BSI treatment. No significant changes were seen with antibiotic prescribing trends in Veterans from 2012 to 2021.

First case of persistent Stenotrophomonas maltophilia bacteraemia due to septic thrombosis successfully treated with a cefiderocol-containing regimen

There is scarce evidence in literature of what should be the best antimicrobial treatment for bloodstream infections (BSIs) sustained by Stenotrophomonas maltophilia, a peculiar pathogen that intrinsically withstands to most of the available antibiotics. Here, we describe a challenging case of a persistent S. maltophilia BSI due to septic thrombosis successfully treated with the addition of the novel siderophore cephalosporin cefiderocol to an only partially effective levofloxacin regimen. Additionally, an intra-lock therapy with trimethoprim/sulfamethoxazole was selected as a strategy to prevent recurrence of infection since complete source control was not possible. The serum bactericidal assay was also used to corroborate the in vivo efficacy of the adopted combination therapy.

Appropriate antibiotic therapy is a predictor of outcome in patients with Stenotrophomonas maltophilia blood stream infection in the intensive care unit.

The study was to assess the relationship between antibiotic therapy and the outcome in intensive care unit (ICU) patients with Stenotrophomonas maltophilia bloodstream infection (BSI). ICU patients with monomicrobial S. maltophilia BSI from January 2004 to December 2019 were included and divided into two groups-those with- and without appropriate antibiotic therapy after BSI-for comparison. The primary outcome was the relationship between appropriate antibiotic therapy and 14-day mortality. The secondary outcome was the influence of different antibiotic therapies: levofloxacin- and trimethoprim-sulfamethoxazole (TMP/SMX)-containing regimens, on 14-day mortality. A total of 214 ICU patients were included. Patients received appropriate antibiotic therapy (n=133) after BSI had a lower 14-day mortality than those (n=81) without appropriate antibiotic therapy (10.5% vs. 46.9%, p<0.001). No difference on 14-day mortality between groups of patients by time of appropriate antibiotic therapy was observed (p>0.05). After a propensity score matching, the results is consistent that 14-day mortality were lower in patients with appropriate antibiotic therapy than those without appropriate antibiotic therapy (11.5% vs. 39.3%, p<0.001). Among patients with S. maltophilia BSI receiving appropriate antibiotic therapy, there was a trend levofloxacin-containing regimens is associated with lower mortality than TMP/SMX-containing regimens (HR 0.233, 95% CI 0.050-1.084, p=0.063). Appropriate antibiotic therapy was associated with decreased 14-day mortality in ICU patients with S. maltophilia BSI regardless of time. Levofloxacin-containing regimens may be better choice than TMP/SMX -containing regimens in treating ICU patients with S. maltophilia BSI.

Outbreak of Stenotrophomonas maltophilia infections in an intensive care unit—Alameda County, California, May–October 2022

Background:Stenotrophomonas maltophilia is a gram-negative, biofilm-producing bacterium that is ubiquitous in water environments and often associated with healthcare-associated infections (HAIs). Outbreaks of S. maltophilia bloodstream infections are a rare event and raise the suspicion of a common source. We used whole-genome sequencing (WGS) for an investigation of a cluster of S. maltophilia HAIs at a single hospital. Methods: A patient was defined as an intensive care unit (ICU) patient with fever and S. maltophilia isolated from a culture and who was treated for an HAI from May to October 2022. The response to the cluster included an epidemiologic investigation, water infection control risk assessments (WICRA), and environmental sampling. We also conducted WGS to characterize and assess relatedness between clinical and environmental S. maltophilia isolates. Results: From May 5 to October 1, 2022, we identified 11 HAIs due to S. maltophilia: 9 bloodstream infections and 2 ventilator-associated pneumonia cases. The initial epidemiological investigation did not identify common medical products, procedures, or personnel as an exposure source. The WICRA identified several breaches that may have exposed patients to contaminated water from sink backsplashes in the ICU, computerized tomography (CT) rooms, and the emergency department. In the CT rooms, saline bags were sometimes used for multiple patients, as were single-use intravenous contrast solution bottles. No additional cases were identified once infection control breaches were mitigated by installing sink splashguards, disinfecting drains, dedicating sink use for handwashing, and adhering to single-patient use of pharmaceutical products in the CT rooms. Of 46 environmental water samples, 19 were culture-positive for S. maltophilia. Isolates available for WGS included 7 clinical isolates (6 blood and 1 respiratory) and 17 environmental isolates. Among the 24 isolates sequenced, 16 unique multilocus sequence types (MLSTs) were identified. The 6 blood isolates sequenced were highly related (ST239, 0–4 high-quality, single-nucleotide variants [hqSNV] over 98.99% core genome), suggesting a common source. Two clusters of related environmental isolates were identified; however, overall MLST and hqSNV analyses suggested no relatedness between clinical and environmental isolates. Conclusions: An ICU cluster of S. maltophilia bloodstream infections was likely associated with water contamination of room surfaces and use of single-use intravenous products for multiple patients in the setting of a national pharmaceutical product shortage. This investigation highlights the importance of strong surveillance and water infection control, including routine assessment of ancillary areas in which intravenous products are administered and interdisciplinary collaboration to properly mitigate nosocomial transmission.Disclosures: None

Risk Factors for Infection and Mortality Associated With Stenotrophomonas maltophilia Bloodstream Infections in Children; Comparison With Pseudomonas aeruginosa Bloodstream Infections.

The increasing incidence of Stenotrophomonas maltophilia ( S. maltophilia ) infections raises concern because of the high fatality/case ratio. This study aimed to evaluate the risk factors for infection and mortality associated with S. maltophilia bloodstream infections (BSIs) in children and compare them with Pseudomonas aeruginosa BSIs. All BSIs caused by S. maltophilia (n:73) and P. aeruginosa (n:80) were enrolled in this study between January 2014 and December 2021 at the Medical School of Ege University. Previous Pediatric Intensive Care Unit (PICU) admission, prior glycopeptide, and carbapenem use were significantly more common in patients with S. maltophilia BSIs ( P = 0.044, P = 0.009, and P = 0.001, respectively) than with P. aeruginosa BSIs. C-reactive protein (CRP) levels were significantly higher in S. maltophilia BSIs ( P = 0.002). Multivariate analysis showed that prior carbapenem use was associated with S. maltophilia BSIs ( P = 0.014, adjusted odds ratio [AOR]: 2.710; 95% confidence interval [CI]: 1.225-5.992). PICU admission because of BSI, prior carbapenem and glycopeptide use, neutropenia, and thrombocytopenia were significantly more common in patients with mortality because of S. maltophilia BSIs ( P < 0.001, P = 0.010, P = 0.007, P = 0.008, P = 0.004, respectively), while only PICU admission because of BSI, and prior glycopeptide use were significant in multivariate analysis (AOR, 19.155; 95% CI: 2.337-157.018; P = 0.006 and AOR, 9.629; 95% CI: 1.053-88.013; P = 0.045, respectively). Prior carbapenem use is a significant risk factor for developing S. maltophilia BSIs. PICU admission because of BSI and prior glycopeptide use are risk factors associated with the mortality rate in patients with S. maltophilia BSIs. Therefore, S. maltophilia should be considered in patients with these risk factors, and empirical treatment should include antibiotics for S. maltophilia .

1844. Mortality associated with Stenotrophomonas maltophilia bloodstream infection in patients with leukemia

Abstract Background Patients with leukemia are disproportionately vulnerable to infections caused by S. maltophilia and mortality approaches 100% in patients with hemorrhagic pneumonia. Trimethoprim-sulfamethoxazole (SXT) is the drug of choice for treatment of infections caused by S. maltophilia however allergies, toxicity, and resistance may preclude its use. We sought to characterize clinical outcomes of patients with leukemia and S. maltophilia bloodstream infection (BSI). Methods Patients with leukemia are disproportionately vulnerable to infections caused by S. maltophilia and mortality approaches 100% in patients with hemorrhagic pneumonia. Trimethoprim-sulfamethoxazole (SXT) is the drug of choice for treatment of infections caused by S. maltophilia however allergies, toxicity, and resistance may preclude its use. We sought to characterize clinical outcomes of patients with leukemia and S. maltophilia bloodstream infection (BSI). Results Ninety-six patients with leukemia and S. maltophilia BSI were identified. The most common diagnosis was acute myeloid leukemia (60%); 31% had prior stem cell transplant. The most common single identified source was respiratory (31%) followed by central venous catheter (CVC, 26%). A single clear source was unable to be identified in 33%.Overall 14-day mortality was 31%. After excluding eleven patients who died within 24 hours, most patients received SXT (72%), followed by ceftazidime (40%), tigecycline (TGC, 40%), and minocycline (26%). SXT was associated with reduced mortality (hazard ratio [HR] 0.15, 95% confidence interval [CI] 0.05 – 0.44, p &amp;lt; 0.01) while TGC was associated with increased mortality (HR 3.13, 95% CI 1.00 – 9.73, p = 0.05). All patients who died were neutropenic at baseline and none had a CVC infection. Conclusion S. maltophilia BSI is associated with high mortality in patients with leukemia, particularly those with neutropenia at baseline. CVC infection alone was not associated with mortality. SXT is associated with reduced mortality relative to other antimicrobials. Alternative agents should be used with caution in these vulnerable patients. Disclosures Samuel L. Aitken, PharmD, MPH, Entasis Therapeutics: Advisor/Consultant|GlaxoSmithKline: Advisor/Consultant|Melinta: Grant/Research Support|Shionogi: Advisor/Consultant Pablo C. Okhuysen, MD, AstraZeneca: Stocks/Bonds|Beam Therapeutics: Stocks/Bonds|Biontech: Stocks/Bonds|Deinove: Grant/Research Support|Ferring: Advisor/Consultant|Glaxo Smith Kleine: Stocks/Bonds|Johnson and Johnson: Stocks/Bonds|Melinta: Grant/Research Support|Merck Sharp &amp; Dohme Corp: Grant/Research Support|Moderna: Stocks/Bonds|Napo Pharmaceuticals: Advisor/Consultant|Napo Pharmaceuticals: Grant/Research Support|Novavax: Stocks/Bonds|Pfizer: Stocks/Bonds|Summit: Advisor/Consultant|Summit: Grant/Research Support.

Risk Factors for Mortality in Patients with Stenotrophomonas maltophilia Bloodstream Infections in Immunocompetent Patients.

This study aimed to evaluate bloodstream infections caused by Stenotrophomonas maltophilia in immunocompetent patients with respect to clinical features and risk factors for mortality. We reviewed bloodstream infections detected between January 1, 2012, and July 1, 2021, to identify nosocomial S. maltophilia bacteremia in Koşuyolu Research and Training Hospital. We identified a total of 97 patients with S. maltophilia bloodstream infections. Of these, 17 patients were excluded because of community-acquired infections (n=9), contamination with S. maltophilia (n=3), and insufficient data (n=5), with 80 (57.5% males) patients remaining for analysis. The source of infection was the respiratory tract in 28 (35%) patients. A central venous catheter was used in 60 (75%) patients, which required replacement in 23 patients within five days after detecting S. maltophilia bacteremia. On antimicrobial susceptibility testing, 71 strains were found to be susceptible and 9 (11.3%) resistant to trimethoprim-sulfamethoxazole. Thirty-day mortality was 33.8%. Non-survivors differed significantly from survivors with respect to higher rates of central venous catheters ( p=0.020), mechanical ventilation (p=0.006), urinary catheters (p=0.021), septic shock (p=0.001), hypoalbuminemia (p=0.026) and thrombocytopenia (p =0.039). S. maltophilia bacteremia was independently associated with mortality in patients with hypoalbuminemia, and replacement of central venous catheters had a protective role in reducing mortality. As with other bacterial infections, S. maltophilia bacteremia is associated with a considerably high mortality rate in patients with cardiac conditions. The replacement of the catheter seems to play a beneficial role in 30-day survival.

Risk Factors and Clinical Outcomes of Stenotrophomonas maltophilia Infections: Scenario in a Tertiary Care Center from South India

Stenotrophomonas maltophilia, a gram-negative non-fermenter has evolved from a colonizer to a significant pathogen over the last decade. It resides in various ecological niches both inside and outside the hospital settings. Infections due to S. maltophilia can be life-threatening, especially in immunocompromised patients. S. maltophilia is intrinsically resistant to most of the antibiotics, which limits treatment options. There are several risk factors involved. The present study was done to assess the risk factors and clinical outcomes associated with S. maltophilia blood stream infections and non-blood stream infections.How to cite this articleVarshini MK, Ganesan V, Sundaramurthy R, Rajendran T. Risk Factors and Clinical Outcomes of Stenotrophomonas maltophilia Infections: Scenario in a Tertiary Care Center from South India. Indian J Crit Care Med 2022;26(8):935–937.

The Threat of Carbapenem-Resistant Gram-Negative Bacteria in Patients with Hematological Malignancies: Unignorable Respiratory Non-Fermentative Bacteria-Derived Bloodstream Infections.

BackgroundCarbapenem-resistant Gram-negative bacteria (CRGNB) bloodstream infection (BSI) pose a significant threat to the prognosis of hematologic malignancies (HM) patients. Understanding the distribution of pathogenic bacteria, changes in carbapenem-resistant trends, risk factors for CRGNB infections, and exploring the early detection measures can help reduce mortality.MethodsWe conducted a multicenter retrospective study of Gram-negative bacteria (GNB) BSI in patients with HM in three university-affiliated hospitals in Hunan Province, China, from January 2010 to December 2020. Demographic and clinical data were collected from the hospital electronic medical records system.ResultsCRGNB caused 138 (15.3%) of 902 GNB BSI. The detection rate of CRGNB increased from 6.4% in 2010–2012 to 35.4% in 2019–2020. The 7-day mortality rate was significantly higher in patients with CRGNB BSI than in patients with carbapenem-susceptible Gram-negative bacteria (CSGNB) BSI [31.9% (44/138) vs 9.7% (74/764), P < 0.001], and the mortality rate in patients with carbapenem-resistant non-fermenting bacteria (CRNFB) bloodstream infections was generally higher than that of carbapenem-resistant Enterobacteriaceae (CRE). Urinary catheter (OR, 2.814; CI=1.395–5.680; P=0.004) and prior exposure to carbapenem (OR, 4.372; CI=2.881–6.635; P<0.001) were independent risk factors for CRGNB BSI. Analysis of co-infections showed that 50%–85% of patients with CRGNB BSI had pulmonary infections, sputum culture results suggested that sputum culture positivity rate was as high as 57.1%–66.7% in patients with carbapenem-resistant Acinetobacter baumannii (CRAB) and Stenotrophomonas maltophilia BSI, and the results of antimicrobial susceptibility testing of sputum cultures were consistent with the blood cultures.ConclusionCarbapenem resistance has dramatically increased in HM patients with GNB BSI in recent years and is associated with a worse outcome, especially for non-fermenting bacteria. In high-risk patients, early screening of the respiratory tract specimens may help to detect CRNFB colonization and protect patients from breakthrough BSI.

A practical update on the epidemiology and risk factors for the emergence and mortality of bloodstream infections from real-world data of 3014 hematological malignancy patients receiving chemotherapy.

Background: Bloodstream infection (BSI) is a common and serious complication after patients with hematologic malignancies (HM) receiving chemotherapy. This study examined real-world data seeking to characterize HM BSI and identify risk factors for BSI emergence and mortality.Methods: We retrospectively analyzed the pathogenic epidemiology, antibiotic resistance, and BSI risk factors in a single-center cohort including 3014 consecutive patients with HM receiving chemotherapy between 2013 and 2016. Results of the pathogenic epidemiology were validated via comparison to available reported data.Results: We found that 725 patients (24.1%) had BSIs. Gram-negative (G-) bacteria represented 64.7% of the 744 isolated pathogenic strains, while Gram-positive (G+) bacteria and fungi accounted for 27.7% and 7.7% of the BSIs, respectively. The most common isolates were Klebsiella pneumoniae (19.2%), and 95.1% of the multidrug-resistant strains (MDR) were extended-spectrum beta-lactamase producing strains. G- bacteria were the main microflora responsible for BSI in our cohort of Chinese HM patients compared to studies in developed countries or in neutropenic children with HM or solid tumors. Multivariate analysis revealed that male sex, age ≥ 45 and < 65 yr, hospital length of stay ≥ 9d, neutropenia ≥ 7d before cultures, ≥ 2 antibiotics, and infections (gastrointestinal, perirectal, or urinary tract) independently predicted BSI emergence. Furthermore, age ≥ 65 yr, neutropenia ≥ 7d before blood cultures, no HM remission, lower white blood cell count, ≥ 3 antibiotics, respiratory infections, and Acinetobacter baumannii and Stenotrophomonas maltophilia BSI were independent predictors of 30-day mortality.Conclusions: G- bacteria were the predominant microflora during the study period and antibiotic resistance levels of the pathogens detected were high, especially for MDR strains. The mortality of BSI patients was high in this large cohort. Close attention should be paid to the risk factors identified here to facilitate timely and effective clinical management of such patients.

Stenotrophomonas maltophilia bloodstream infections in adult recipients of umbilical cord blood transplantation

Limited data are available on Stenotrophomonas maltophilia bloodstream infections (SM-BSIs) and the therapeutic efficacy of trimethoprim–sulfamethoxazole (SXT) against SM-BSI in umbilical cord blood transplant (uCBT) recipients. Medical and microbiological records of adult patients who received uCBTs between December 2008 and December 2015 at Toranomon Hospital (Tokyo, Japan) were reviewed. The efficacy and safety of SXT were evaluated only for recipients who were treated with ≥7 days of intravenous SXT for SM-BSI (evaluation cohort). Of 561 uCBT recipients, 34 developed SM-BSI. Diabetes mellitus (P = .005) and age ≥ 60 years (P = .013) were significant independent risk factors for SM-BSI. Moreover, SM-BSI was identified as an independent risk factor for all-cause mortality up to 100 days following uCBT (P = .025). Of the 34 recipients with SM-BSI, 24 were treated with an intravenous SXT-containing regimen (iSXT-CR). Septic shock (P = .0021), pneumonia (P = .011), neutropenia (P = .0015), and systemic steroid administration (P = .018) were identified as significant independent risk factors for 7-day crude mortality. The evaluation cohort included nine recipients. Doses of SXT were 2.4 to 6.9 mg/kg/day of the trimethoprim component. Of the nine recipients, five developed SM-BSI during the pre-engraftment phase. The 30-day crude-mortality rate and clinical cure rate of the cohort were 22% and 67%, respectively. Only one of the nine recipients experienced significant neutrophil toxicity. In this study, the epidemiology of SM-BSI in uCBT recipients was determined and its negative impact on survival was demonstrated. A low- to moderate-dose iSXT-CR appeared to be a tolerable and important therapeutic option for SM-BSI in the uCBT setting, including during the pre-engraftment phase.

Risk Factors of Stenotrophomonas maltophilia Blood Stream Infections: Comparison With Other Gram-Negative Blood Stream Infections in Children.

Stenotrophomonas maltophilia, is a nonfermentative, aerobic, Gram-negative bacilli which is intrinsically resistance to several antibiotics. Treatment options for this bacteria are quite different from the other Gram-negative bacilli, which can represent a therapeutic challenge. To initiate appropriate empiric treatment and to reduce mortality, differentiation of S. maltophilia from other Gram-negative bacteria is critically important. The aim of this study is to distinguish the risk factors of S. maltophilia blood stream infections (BSI) from other Gram-negative BSI. This was a retrospective, case-control study. Patients with S. maltophilia BSI were selected as cases and patients with non-S. maltophilia Gram-negative BSI were selected as controls. Demographic and clinical characteristics of patients were recorded. Forty-eight cases with S. maltophilia BSI and 144 controls were enrolled in the study. Risk factors for S. maltophilia BSI compared with the control group includes prior use of antibiotics, especially carbapenem, pediatric intensive care unit stay, mechanical ventilator use, indwelling catheters and duration of hospitalization. Breakthrough infection by S. maltophilia can occur in severely ill patients being treated with carbapenem. In the presence of risk factors, to reduce morbidity and mortality, S. maltophilia should be kept in mind when starting empiric treatment.

The Burden of Bloodstream Infections due to Stenotrophomonas Maltophilia in the United States: A Large, Retrospective Database Study.

Background Stenotrophomonas maltophilia is an opportunistic pathogen observed in both nosocomial and community-onset infections. S. maltophilia is intrinsically resistant to many currently available broad-spectrum antibiotics and is often not included in antimicrobial resistance surveillance studies or stewardship programs’ guidelines.MethodsA retrospective cohort study of patients with S. maltophilia bloodstream infection (BSI) in the United States was conducted using the 2010–2015 US Premier Healthcare Database. This study described patient characteristics, infection characteristics, antibiotic treatment, and discharge status.Results S. maltophilia was the most common carbapenem-resistant, gram-negative pathogen causing BSIs in this database. Of 486 unique patients with S. maltophilia BSI, 44.6% were assessed as community-onset, 95% of cultures were susceptible to trimethoprim-sulfamethoxazole (TMP-SMX), and 84% were susceptible to fluoroquinolones; 39.1% of patients received a potentially effective antibiotic (fluoroquinolone, doxycycline, ceftazidime, minocycline, or TMP-SMX) during the empiric treatment period (≤3 days post–index culture date), whereas 85.8% received a potential effective antibiotics during the definitive treatment period. The most common antibiotic received as definitive treatment was levofloxacin (48.9%). TMP-SMX was used infrequently empirically (10.5%) and in 38.3% during the definitive period. Compared with BSIs caused by other carbapenem-resistant gram-negative pathogens, S. maltophilia BSIs were more likely to be community-onset, and were more likely to be discharged to home and to have a lower mortality rate.ConclusionsThis study demonstrated that patients at risk for S. maltophilia BSI are highly variable and that standard of care is not clearly defined, leading to questions regarding the appropriateness of antibiotic treatment among patients. Further efforts are needed to better recognize and treat S. maltophilia BSI.

2689. Stenotrphomonas maltophilia, The Hidden Threat Among Pediatric Cancer Patients

BackgroundStenotrophomonas maltophilia is an emerging nosocomial pathogen in immunocompromised patients. Although S. maltophilia exhibits limited pathogenicity in immunocompetent hosts, it has been shown to cause fatal infections in patients with malignancies. The objective of this study to analyze the clinical characteristics, susceptibility pattern, and treatment outcome of S. maltophilia among pediatric cancer patients.MethodsRetrospective analysis including all pediatric cancer patients treated at children cancer hospital Egypt (CCHE) with S. maltophilia bloodstream infection from June 2013 till June 2018.Results281 isolates among 135 pediatric cancer patients. Most are hematological malignancies 67(50%), solid tumors 55 (40%) and post-transplant 13(10%). Most common hematological malignancies were acute lymphoblastic leukemia 34 patients (25%) while brain tumor was the most common solid tumors 20 patients (15%). The spectrum of infections includes bacteremia in 61 patients (45%) catheter-related in 34 (25%), pneumonia in 22 (16%), skin and soft-tissue infection in 11(8%) meningitis in 5 (3%) and disseminated infections with multiorgan involvement in 4(3%) patients. 46 patients (34%) was admitted in intensive care unit (ICU), 67 inpatient (50%), 11 (8%) stem cell transplant unit and 11 patient (8%) from emergency and outpatient department. The isolates revealed 80% susceptibility to Trimethoprim-Sulfamethoxazole (TMP-SMX), 77% to ciprofloxacin, 50% to cefepime and ceftazidime, 63% to amikacin, 48% to piperacillin–tazobactam, 93% to colistin, 97% to tigecycline. Day 30 mortality (Crude mortality rate) 33 patients (25%) while S. maltophilia attributable mortality (died within 7 days of culture isolation) was 17 patients (13%). Patients with pneumonia, (TMP-SMX) resistance and ICU admission were associated with a significant risk of mortality.ConclusionStenotrphomonas bloodstream is a serious pathogen and hidden threat among pediatric cancer patients associated with high mortality rate.Disclosures All authors: No reported disclosures.

PS1279 A PRACTICAL UPDATE ON THE EPIDEMIOLOGY AND RISK FACTORS FOR THE EMERGENCE AND MORTALITY OF BLOODSTREAM INFECTIONS IN 3014 PATIENTS WITH HEMATOLOGICAL MALIGNANCY RECEIVING CHEMOTHERAPY

Background:The pathogenic epidemiology, antibiotic resistance, and risk factors of bloodstream infections (BSIs) in patients with hematologic malignancies (HMs) receiving chemotherapy is importment for clinican.Aims:To investigate the pathogenic epidemiology and antibiotic resistance of bloodstream infections (BSIs) in patients with hematologic malignancies (HMs) receiving chemotherapy, and to determine the risk factors for BSIs.Methods:Retrospective chart review of patients diagnosed with HMs (n = 3014) was performed (1/2013–12/2016), and patients classified as having BSIs (n = 725) or not (n = 2289). Clinical characteristics and pathogens were evaluated, and risk factors for BSIs identified by univariate and multivariate Logtistic and COX regression analyses.Results:BSI frequency was 24.1%, with 744 different isolated strains in 725 cases. Gram‐negative (G‐) represented 64.7% of the 744 isolated strains, while Gram‐positive (G+) and fungi were 27.7% and 7.7%, respectively. The most common isolates were Klebsiella pneumoniae (19.2%), and 90% of extended‐spectrum beta‐lactamases (ESBL)‐producing enterobacteria were multidrug‐resistant. Methicillin‐resistant Coagulase‐negative Staphylococci and Methicillin‐resistant Staphylococcus aureus accounted for 87.16% and 37.93% of the cases, respectively. Multivariate analysis revealed that male, age ≥ 45 and &lt;65 yr, hospital length of stay (LOS) ≥ 9d, neutropenia ≥ 7d before BSIs, ≥ 2 antibiotics, gastrointestinal, perirectal and urinary tract infections independently predicted BSIs emergence. Furthermore, age ≥ 65, neutropenia ≥ 7d before BSIs, no HM remission, lower white blood cell count, ≥ 3 antibiotics, respiratory infections, and Acinetobacter baumannii and Stenotrophomonas maltophilia BSIs were independent predictors of 30‐day mortality.Summary/Conclusion:Antibiotic resistance was high, outcome was poor, and mortality due to BSIs was high in this patient cohort. Therefore, close attention should be paid to the risk factors identified here during management of these patients with BSIs.image

Clinical features and prognosis of children with hematological malignancies after chemotherapy with Stenotrophomonas maltophilia blood stream infection

Objective To investigate the clinical features and prognosis of children with hematological malignancies after chemotherapy accompanied with Stenotrophomonas maltophilia blood stream infection (BSI). Methods The clinical data and antimicrobial susceptibility test of 25 hospitalized children with hematological malignancies who were diagnosed as Stenotrophomonas maltophilia BSI in the Department Pediatric Hematology of Fujian Medical University Union Hospital from January 2013 to May 2018 were analyzed retrospectively. Results A total of 25 children, including 18 males and 7 females with the median age 4 (1-11) years old were diagnosed as hematological malignancies and all received chemotherapy. The frequent risk factors of Stenotrophomonas maltophilia BSI in children with hematological malignancies included prior carbapenem antibiotic for more than 1 week (80%, 20/25), and neutropenia for more than 1 week (68%,17/25) and indwelling central venous catheter (48%, 12/25). Clinically, the main manifestations included neutropenia with fever after chemotherapy; however, anti-pseudomonas cephalosporin/carbicillin antibiotic combined with vancomycin and anti-fungal therapies were ineffective. Drug susceptibility test showed that all strains were sensitive to compound sulfamethoxazole, levofloxacin and minocycline. Before blood culture report, 3 patients died of septic shock, pulmonary hemorrhage and respiratory failure; after blood culture report, the treatment regimens were adjusted to compound sulfamethoxazole combined with cefoperazone sodium and sulbactam sodium (200-260 mg·kg-1·d-1) or levofloxacin anti-infective. Finally, 18 patient was cured, 2 patients died of the bad efficacy of underlying diseases, and 2 patients died of pulmonary hemorrhage. The overall fatality rate was 28% (7/25) and the related mortality rate caused by Stenotrophomonas maltophilia BSI was 20% (5/25). Conclusion Stenotrophomonas maltophilia BSI in children with hematological malignancies after chemotherapy has a high fatality rate, and better basic disease control and appropriate antibacterial therapy are the key to improve the prognosis. Key words: Hematologic neoplasms; Hematologic diseases; Stenotrophomonas maltophilia; Blood stream infection; Child; Prognosis

Stenotrophomonas maltophilia bacteremia and pneumonia at a tertiary-care oncology center: a review of 16years.

The aim of this study was to describe the clinical characteristics and antimicrobial patterns of Stenotrophomonas maltophilia bloodstream infections (BSI) and pneumonia episodes in patients with cancer. Patients with S. maltophilia BSI or pneumonia admitted from 1 Jan. 2000 to 31 Dec. 2016 were identified at the Instituto Nacional de Cancerología (INCan), a tertiary-care oncology hospital in Mexico City. During the study period, there were 171 isolates identified. The mean age of the whole group was 46.9 ± 17.4years; 99 (57.9%) were women. There were 95 BSI: 64 ambulatory catheter-related BSI (CRBSI), 20 nosocomial CRBSI, and 11 secondary BSI. Mortality was higher in nosocomial CRBSI (40%) vs. that in ambulatory CRBSI (7.8%) (p = 0.001). There were 76 pneumonia episodes; all were nosocomial acquired; 46 (60.5%) ventilator-associated. From all the group, nine strains (5.2%) were resistant to sulfamethoxazole/trimethoprim/(SMX/TMP). At the first month, 54 patients (31.6%) have died, 38 due to pneumonia (70%) and 16 due to BSI (30%, p < 0.001). Multivariate analysis showed that removal of central venous catheter was associated with a favorable outcome in patients with bacteremia. For patients with pneumonia, age ≥ 65years and inappropriate antimicrobial treatment were risk factors associated with 30-day mortality. S. maltophilia related with ambulatory CRBSI have a better prognosis than other sources of BSI. Older patients with pneumonia who do not receive appropriate antibiotics have higher mortality. SMX/TMP is still the antibiotic of choice.