Non-fermenting Gram-negative Bacilli Research Articles

P-297. Prospective Study on Microbiological Profile of Nosocomial Infections due to Gram negative lactose non-fermentative Bacteria in a Tertiary Care Hospital in South India

Abstract Background Non-fermentative gram-negative bacteria (NFGNB) infections that are acquired in hospitals have particularly concerning characteristics; identifying these features can aid in prevention and improve the standard of care provided within hospital premises. This study aims to find out the nosocomial infections caused by NFGNB, its sensitivity pattern, length of culture reporting time, and patients with ICU stay. Methods A prospective observational study was conducted in a tertiary care hospital located in southern India during the 4 months of January-April 2024. Data were taken from the Department of Microbiology regarding the prevalence of NFGNB isolates from different culture samples and their sensitivity pattern. The number of MDR isolates throughout the four months, their susceptibility pattern, and the duration of culture reporting time for all NFGNB isolates were examined. Descriptive analysis was used to look at patient demographics, inpatient department, and ICU admission. Statistical analysis was done by Microsoft Excel. Results Total 72(18.6%) samples were recorded as NFGNB from 386 culture positive samples isolated from the Department of Microbiology. The most common isolate was Acinetobacter spp (38.8%) followed by Pseudomonas spp (27.7%). The mean of our study participants was found to be 55 years, with a male: female ratio 2:1. The General Medicine department showed maximum isolates i.e, 25% followed by Hepatology department i.e, 16.6%. Maximum NFGNB isolates are from Urine sample (33.3%) followed by Blood sample (27.8%). The mean time of culture reporting for NFGNB was 72 hours. Out of 72 NFGNB samples, 28(38.8%) were Multi-drug resistant isolates and 29(40.2%) required ICU admission. Conclusion NFGNB function as nosocomial pathogens, their startling resistance is a concern to epidemiology and medical care. These isolated pathogens have been manually reported for a considerable amount of time. Rapid culture identification methods would assist identify resistant diseases early and improve patient outcomes in low- and middle-income countries. Future studies should focus on implementation of approaches to reduce the incidence and resistance of nosocomial infections in LMICs. Disclosures All Authors: No reported disclosures

P-426. Antimicrobial Resistance Focus in French ICU: A national surveillance network analysis on ventilator acquired pneumonia

Abstract Background The aim of this study was to perform a characterization of patients who underwent mechanical ventilation, the incidence rate of ventilator acquired pneumoniae (VAP) as well as identification of the pathogens involved, their resistance profiles, and the associated clinical outcomes. This group will be scrutinized for patterns and outcomes specifically associated with ventilator use. Cumulative incidence of VAP Methods Adult patients undergoing mechanical ventilation hospitalized in France for at least 48 hours in ICU participating to REA-REZO surveillance network between 2018 and 2021 were included in this cohort. To estimate the cumulative incidence of VAP, extubation and death were considered as competing event. Description of the cohort Results In this cohort, 98 047 patients were included. Among them, 12 251 (12.5%) had a VAP; the incidence rate for 1000 ventilation days was 18.9 cases per 1000 ventilation days. The median age of the cohort is 66 [55-75] years old with a male predominance (63.0 %). The SAPS score is 49 [36-63], the mortality is 24.4 % and the median ICU length of stay is 7 [4-15] days. Ventilated patients are more frequently admitted for medical (63.0 %) compared to surgical (37.0%) reason. At day 30, the attributable mortality associated with ventilator-associated pneumonia (VAP) was estimated at 4.9% (3.7% - 6.2%). Out of 15,575 diagnosed cases of VAP, there were 4,695 instances of polymicrobial VAP, which constitutes 30.1% of the cases. Non-fermenting Gram-negative bacteria were a significant group, contributing to 25.4% of the VAP cases, with Pseudomonas aeruginosa being the most significant contributor (3 924 cases, 76.2% of non-fermenters) Description of the microbial ecology of VAP Conclusion The development of VAP is frequent, especially in patients admitted for medical reasons, with high severity and appears to be associated with an increased use of medical devices, like urinary and central venous catheters, reflecting the complexity of their clinical management. Disclosures Xavier Bourge, PharmD, MSD France: Employee Arnaud Friggeri, MD, MSD France: Advisor/Consultant Alain Lepape, MD, MSD France: Grant/Research Support Claire Prevot, n/a, MSD France: Employee Anais Machut, n/a, MSD France: Grant/Research Support Charles-Hervé Vacheron, MD, MSD France: Grant/Research Support

P-1484. In vitro Activity of Cefiderocol and Comparator Agents Against Non-fermentative Gram-negative Bacilli Isolated from Patients Hospitalized with Pneumonia as part of the SENTRY Global Surveillance Program (2020-2022)

Abstract Background Cefiderocol (CFDC) is a siderophore-conjugated cephalosporin with broad activity against Gram-negative bacteria including non-fermenters resistant to carbapenems. The in vitro activity of CFDC and comparators was evaluated against glucose non-fermenting Gram-negative bacteria isolated from patients hospitalized with pneumonia.Table 1:Activity of cefiderocol and comparator agents against Pseudomonas aeruginosa, Acinetobacter baumannii-calcoaceticus complex, and Stenotrophomonas maltophilia isolates from patients hospitalized with pneumonia from 2020-2022 Methods 5,995 isolates were collected between 2020-2022 from pneumonia patients as part of the global SENTRY Antimicrobial Surveillance Program, including: 3,809 Pseudomonas aeruginosa (PSA), 1,092 Acinetobacter baumannii-calcoaceticus complex (ABC), 808 Stenotrophomonas maltophilia (STM), 104 Achromobacter spp. (ACHR), 81 Burkholderia cepacia complex (BURK), and 101 other isolates. Minimum inhibitory concentrations (MIC) were assessed by CLSI guidelines using broth microdilution with cation-adjusted Mueller-Hinton broth (CAMHB) for comparators and iron-depleted CAMHB for CFDC. Susceptibility was assessed according to 2024 CLSI, FDA, and EUCAST breakpoints. Carbapenem resistance (CR) was defined as resistant to meropenem and imipenem by CLSI breakpoints. Results Against PSA, CFDC and β-lactam/β-lactamase inhibitor combinations all had susceptibility >95%. However only CFDC maintained high susceptibility against CR-PSA with 99.3% of the isolates being susceptible by CLSI breakpoints. No other comparator had > 90% susceptibility against CR-PSA (Table 1). Against ABC, CFDC demonstrated 97.5% susceptibility by CLSI breakpoints. This high susceptibility was maintained against CR-ABC with 96.1% susceptibility using CLSI breakpoints. Colistin showed 75.5% susceptibility per EUCAST breakpoint, but ceftazidime and ampicillin-sulbactam had no appreciable activity. CFDC, trimethoprim-sulfamethoxazole, and minocycline all showed >90% susceptibility against STM. Against ACHR and BURK, CFDC had high activity, with MIC50/90 values of 0.03/0.5 and 0.06/1 mg/L, respectively. Conclusion CFDC demonstrated high in vitro activity against glucose non-fermenters isolated from hospitalized patients with pneumonia. In particular, CFDC maintained high susceptibility against CR isolates making it an important treatment option for pneumonia patients at risk of infection with a CR non-fermenter. Disclosures Frank Kung, PhD, Shionogi Inc: Employee Sean T. Nguyen, PharmD, Shionogi Inc.: Employee Boudewijn L. DeJonge, PhD, Shionogi Inc.: Employee Christopher M. Longshaw, PhD, Shionogi BV: Employee Jason J. Bryowsky, PharmD, MS, Shionogi: Employee Rodrigo E. Mendes, PhD, GSK: Grant/Research Support Miki Takemura, n/a, Shionogi & Co., Ltd.: Employee Yoshinori Yamano, PhD, Shionogi & Co., Ltd.: Employee

Etiological and epidemiological aspects of nosocomial bacterial infections during the COVID-19 pandemic

The most important aspect of the problem of the quality of medical care is the epidemiological safety of the therapeutic and diagnostic process. The intensive development of high-tech, invasive methods of diagnosis and treatment, combined with the widespread spread of multidrug-resistant microorganisms, determine the need for continuous improvement of the system of supervision and control of infections associated with medical care (ISMP). The aim of the study was to identify cases of ventilator-associated lower respiratory tract infections in intensive care units (ICU) when infected with ESСAPE group bacteria; to study their prevalence, etiological structure and epidemiological significance in intensive care patients with COVID-19 undergoing invasive artificial ventilation (ventilator). The results of the study showed that in COVID-19 patients who received respiratory support in the ventilator mode, representatives of the ESСAPE group of bacteria (with genetic determinants of multiantibiotic resistance) were found more than 2 times more often than in surgical patients, which indicates the important epidemiological significance of aerobic gram-negative bacteria and non-fermenting gram-negative bacteria of the ESСAPE spectrum in patients COVID-19 in the formation of colonization and ventilator-associated infection of the respiratory tract. At the same time, both in COVID-19 patients and in patients with a surgical ICU, gram-negative bacteria of the genus Klebsiella spp., producing beta-lactamase, as well as non-fermenting gram-negative microorganisms Acinetobacter spp, were prioritized in the etiological structure. and P. aegidiposa, characterized by pronounced acquired resistance to antibiotics of the carbapenem group and are the prerogative of intensive care units. To ensure the epidemiological safety of medical care during ventilation, it is necessary to implement a strategy of empirical and targeted antibiotic therapy; monitoring of antibiotic resistance; conduct continuous epidemiological surveillance in the ICU with full collection of information on etiological agents, cases of respiratory tract infection and tighten epidemiological control over the preparation and conduct of ventilation.

Bacterial contamination of mobile handwashing stations in hospital settings in the Democratic Republic of the Congo

BackgroundAs part of the containment of the COVID-19 pandemic, mobile handwashing stations (mHWS) were deployed in healthcare facilities in low-resource settings. We assessed mHWS in hospitals in the Democratic Republic of the Congo for contamination with Gram-negative bacteria.MethodsWater and soap samples of in-use mHWS in hospitals in Kinshasa and Lubumbashi were quantitatively cultured for Gram-negative bacteria which were tested for antibiotic susceptibility. Meropenem resistant isolates were assessed for carbapenemase enzymes using inhibitor-based disk and immunochromatographic tests. Mobile handwashing stations that grew Gram-negative bacteria at counts > 10,000 colony forming units/ml from water or soap were defined as highly contaminated.ResultsIn 26 hospitals, 281 mHWS were sampled; 92.5% had the “bucket with hand-operated tap” design, 50.5% had soap available. Overall, 70.5% of mHWS grew Gram-negative bacteria; 35.2% (in 21/26 hospitals) were highly contaminated. Isolates from water samples (n = 420) comprised 50.3% Enterobacterales (Klebsiella spp., Citrobacter freundii, Enterobacter cloacae), 14.8% Pseudomonas aeruginosa and 35.0% other non-fermentative Gram-negative bacteria (NFGNB, including Chromobacterium violaceum and Acinetobacter baumannii). Isolates from soap samples (n = 56) comprised Enterobacterales (67.9%, including Pluralibacter gergoviae (n = 13)); P. aeruginosa (n = 12) and other NFGNB (n = 6). Nearly one-third (31.2%, 73/234) of Enterobacterales (water and soap isolates combined) were multi-drug resistant; 13 isolates (5.5%) were meropenem-resistant including 10 New Delhi metallo-beta-lactamase (NDM) producers. Among P. aeruginosa and the other NFGNB, 7/198 (3.5%) isolates were meropenem resistant, 2 were NDM producers. Bacteria listed as critical or high priority on the World Health Organization Bacterial Priority Pathogens List accounted for 20.3% of isolates and were present in 12.0% of all mHWS across 13/26 hospitals. Half (50.5%) of highly contaminated mHWS were used by healthcare workers and patients as well as by caretakers and visitors.ConclusionsMore than one third of in-use mobile handwash stations in healthcare facilities in a low resource setting were highly contaminated with clinically relevant bacteria, part of which were multidrug resistant. The findings urge a rethink of the place of mobile handwash stations in healthcare facilities and to consider measures to prevent their contamination.

In Silico Evaluation of Potential NDM-1 Inhibitors: An Integrated Docking and Molecular Dynamics Approach.

Background/Objectives: Non-fermenting Gram-negative bacteria are resistant to most antibiotics, due to the production of enzymes such as NDM-1. Faced with this challenge, computational methods have become essential for the design of NDM-1 carbapenemase inhibitors, optimizing both the time and cost of the development of new lead molecules. Methods: In this study, molecular docking and molecular dynamics (MD) simulations were performed in order to identify effective inhibitors against the NDM-1 enzyme. Protein preparation was carried out using UCSF Chimera and AutoDockTools 1.5.7, while ligands were prepared with MarvinSketch, Avogadro, and AutoDockTools 1.5.7. Molecular docking was run with AutoDock4 and AutoDock4Zn, determining that molecules M26 (-13.23 kcal/mol with AutoDock4 and -13.11 kcal/mol with AutoDockZn) and M25 (-10.61 kcal/mol with AutoDock4 and -11.18 kcal/mol with AutoDockZn) presented the best binding energy affinities with NDM-1. The M26 molecule formed six hydrogen bonds with the enzyme. Results: MD simulations, performed with GROMACS, indicated that the NDM-1-M26, NDM-1-M35, and NDM-1-M37 complexes showed conformational stability and flexibility. Conclusions: These results suggest that the M26, M37, and M35 ligands have significant potential as leading candidates in the development of new NDM-1 inhibitors, outperforming the antibiotic Meropenem in some respects.

Etiological profile and antimicrobial susceptibility pattern of blood culture isolates for bloodstream infection

Objectives: The objective of the study is to identify and study the antimicrobial susceptibility pattern of various causative agents of bloodstream infection (BSI) in a tertiary care hospital. Materials and Methods: This was a retrospective observational study conducted from October 2022 to September 2023. Paired blood culture samples were collected aseptically and incubated in BD BACTEC FX-40, a fully automated blood culture system, for 5 days. When the bottle was “flagged positive,” gram staining was done, followed by subculture onto Blood agar and MacConkey agar. Species identification and antibiotic susceptibility testing were performed using the VITEK 2 Compact system and interpreted according to Clinical Laboratory Standard Institute guidelines. Statistical analysis: The data were analyzed using the Statistical Package for the Social Sciences version 20.0. Results: 10,449 blood cultures were received during the 1-year study period, out of which 13.2% (1378 samples) showed growth of pathogenic organisms. Gram-negative bacilli (810/1,378, 58.8%) were the most common etiological agents, and Klebsiella pneumoniae was the most predominant pathogen recovered . Candida spp. were recovered in (150/1378, 10.9%) isolates. A high rate of antimicrobial resistance (AMR) was noted, including (26/46, 56.5%) methicillin-resistant Staphylococcus aureus, (9/125, 7.2%) vancomycin-resistant enterococci, and (269/536, 50.2%) carbapenem-resistant enterobacterales. The current study also highlights high resistance among non-fermenting Gram-negative bacteria. Conclusions: Gram-negative bacilli are the most common cause of BSIs in our setup. A high level of AMR is observed among the pathogens. The formulation of an effective antimicrobial stewardship program and its strict compliance is the need of the hour.

Distribution of values of indicators of minimum suppressive concentrations of antibiotics in relation to gram-negative bacterial strains isolated from cystic fibrosis

Introduction. Cystic fibrosis is a severe chronic genetic disease, in which the microbiological status of the patient plays an important role, because it will determine the severity of the respiratory infection. In recent years, representatives of non-fermenting gram-negative bacteria (NFGNB) - P. aeruginosa, B. cenocepacia, Axylosoxidans; as well as representatives of the order Flavobacteriales - have become of great clinical importance in patients with cystic fibrosis. A feature of some representatives of NFGNB is the formation of resistance to antibacterial drugs, due to prolonged antimicrobial therapy. In addition to the acquired, there is a high level of natural resistance, and therefore the possibilities of using antibacterial drugs are significantly limited.Aim. To estimate the distribution of the values of the minimum suppressive concentrations (MSC) of cefepim / sulbactam, piperacillin / tazobactam, biapenem in relation to 100 strains of Gram-negative bacteria isolated from respiratory samples from patients with cystic fibrosis.Materials and methods. To date, new compounds have appeared with potential activity against the strains under consideration - cefepim / sulbactam, piperacillin / tazobactam, biapenem. We selected 100 bacterial strains isolated from respiratory samples from patients with cystic fibrosis from various regions of the Russian Federation. Among them, 69 strains are Pseudomonas aeruginosa, 6 - Achromobacter xylosoxidans, 14 - Burkholderia cenocepacia, 10 - Chryseobacterium spp., 1 - Elizabethkingia miricola. MSC values were determined for 3 antimicrobial drugs: cefepim / sulbactam, piperacillin / tazobactam, biapenem.Results and discussions. According to the data obtained, it was found that most strains of Pseudomonas aeruginosa, Achromobacter xylosoxidans have a high level of sensitivity to cefepim/sulbactam, piperacillin/tazobactam. The criteria for evaluating the MSC indicators of the studied drugs in relation to Burkholderia cenocepacia and representatives of the order Flavobacteriales have not been determined, however, it is worth noting that most isolates have demonstrated an achievable value of MSC indicators. This suggests the possibility of practical application of antimicrobial drugs under test.Conclusions. The data obtained indicate the microbiological efficacy of the drugs: cefepim/sulbactam, piperacillin/tazobactam, biapenem relative to NFGNB isolated from patients with cystic fibrosis.

Prevalence, Distribution and Antimicrobial Susceptibility of Enterobacteriaceae and Non-Fermenting Gram-Negative Bacilli Isolated From Environmental Samples in a Veterinary Clinical Hospital in Madrid, Spain.

Managing infections caused by multidrug-resistant Gram-negative bacilli is a major public health concern, particularly in hospitals where surfaces can act as reservoirs for resistant microorganisms. Identifying these bacteria in hospital environments is crucial for improving healthcare safety. This study aimed to analyse environmental samples from a veterinary hospital to identify prevalent microorganisms and detect antimicrobial resistance patterns. A total of 183 surface samples were collected from 26 areas at the Veterinary Clinical Hospital of Alfonso X el Sabio University in Madrid. The isolated strains were identified, and susceptibility profiles were determined via the disk diffusion method. Clonality analysis was performed using pulsed-field gel electrophoresis. In total, 109 strains were isolated: 76.15% from the Enterobacteriaceae family and 23.85% non-fermenting Gram-negative bacilli. The isolates included Klebsiella, Enterobacter, Escherichia and Pseudomonas species, which could include high-risk clones, given their ability to carry several antimicrobial resistance genes. The equine area had the highest number of isolates (n = 71), accounting for 65% of the total. High resistance indices were observed against at least five of the 16 antibiotics tested, indicating significant multidrug resistance. Clonality analysis suggested potential cross-transmission within the facility. This study sampled hospital surfaces but not personnel or animals, making contamination sources unclear. Without resampling, the effectiveness of cleaning protocols remains uncertain. Results suggest that hospital staff play a key role in bacterial transmission. The lack of specialised preventive measures in veterinary hospitals highlights a need for further research and improvement.

Biofilm Formation and Plasmid-Mediated Quinolone Resistance Genes at Varying Quinolone Inhibitory Concentrations in Quinolone-Resistant Bacteria Superinfecting COVID-19 Inpatients.

The likelihood of antimicrobial failure in COVID-19 patients with bacterial superinfection arises from both phenotypic (biofilms) and genotypic mechanisms. This cross-sectional study aimed to determine the inhibitory concentrations of quinolones-nalidixic acid, norfloxacin, ciprofloxacin, ofloxacin, and levofloxacin-in biofilm formers (minimum biofilm inhibitory concentration [MBIC]) and nonformers (minimum inhibitory concentration [MIC]) and correlate inhibitory concentrations with plasmid-mediated quinolone resistance (PMQR) genes in quinolone-resistant bacteria isolated from COVID-19 inpatients. Quinolone-resistant bacteria (n = 193), verified through disc diffusion, were tested for quinolone inhibitory concentrations using broth microdilution and biofilm formation using microtiter plate methods. The polymerase chain reaction was used to detect PMQR genes. Study variables were analyzed using SPSS v.17.0, with a significance level set at P <0.05. MIC-to-MBIC median fold increases for ciprofloxacin, ofloxacin, and levofloxacin were 128 (2-8,192), 64 (4-1,024), and 32 (4-512) in gram-positive cocci (GPC, n = 43), respectively, whereas they were 32 (4-8,192), 32 (4-2,048), and 16 (2-1,024) in fermentative gram-negative bacilli (F-GNB, n = 126) and 16 (4-4,096), 64 (2-64), and 16 (8-512) in nonfermentative gram-negative bacilli (NF-GNB, n = 24). In biofilm-forming F-GNB and NF-GNB, qnrB (10/32 versus 3/10), aac(6')-Ib-cr (10/32 versus 4/10), and qnrS (9/32 versus 0/10) genes were detected. A 32-fold median increase in the MIC-to-MBIC of ciprofloxacin was significantly (P <0.05) associated with qnrA in F-GNB and qnrS in NF-GNB. Biofilms formed by F-GNB and NF-GNB were significantly associated with the aac(6')-Ib-cr and qnrS genes, respectively. Nearly one-third of the superinfecting bacteria in COVID-19 patients formed biofilms and had at least one PMQR gene, thus increasing the need for quinolones at higher inhibitory concentrations.

Duration of Antimicrobial Treatment in Adult Patients with Pneumonia: A Narrative Review.

Pneumonia remains a major global health concern, causing significant morbidity and mortality among adults. This narrative review assesses the optimal duration of antimicrobial treatment in adults with community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), and ventilator-associated pneumonia (VAP). Current evidence about the impact of treatment duration on clinical outcomes demonstrates that shorter antibiotic courses are non-inferior, regarding safety and efficacy, compared to longer courses, particularly in patients with mild to moderate CAP, which is in line with the recommendations of international guidelines. Data are limited regarding the optimal antimicrobial duration in HAP patients, and it should be individually tailored to each patient, taking into account the causative pathogen and the clinical response. Shorter courses are found to be as effective as longer courses in the management of VAP, except for pneumonia caused by non-fermenting Gram-negative bacteria; however, duration should be balanced between the possibility of higher recurrence rates and the documented benefits with shorter courses. Additionally, the validation of reliable biomarkers or clinical predictors that identify patients who would benefit from shorter therapy is crucial. Insights from this review may lead to future research on personalized antimicrobial therapies in pneumonia, in order to improve patient outcomes.

The Clinical Impression of NDM-producing Acinetobacter baumannii in Intensive Care Units of the University Referral Hospital in North India.

Carbapenem-resistant Acinetobacter baumannii (CRAb), a major public health threat, causes severe infections in Intensive Care Unit (ICU) patients. It resists β-lactam antibiotics through mechanisms like New Delhi metallo-beta-lactamase (NDM). In ICU patients, 69 Acinetobacter species were isolated from 86 non-fermenting Gram-negative bacilli. Isolates were identified using biochemical methods and Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS), and carbapenem resistance detection was done by both phenotypic (mCIM and eCIM) and molecular methods. Out of 66 A. baumannii, 61 were carbapenem-resistant, with 20 confirmed as NDM producers. NDM-positive isolates exhibited higher resistance and were associated with significant mortality (75%). NDM-positive Acinetobacter isolates are significant ICU pathogens with poor outcomes. Key risk factors include prolonged ICU stays, prior antimicrobial use, and inadequate therapy. Early detection and infection control are crucial. NDM-positive Acinetobacter infections in ICU patients are linked to poor outcomes, highlighting the need for early detection and control measures. Singh S, Verma A, Venkatesh V, Verma S, Reddy DH, Agrawal A. The Clinical Impression of NDM-producing Acinetobacter baumannii in Intensive Care Units of the University Referral Hospital in North India. Indian J Crit Care Med 2024;28(11):1044-1049.

Detection of carbapenem-resistant gram-negative bacilli in Japan using the fully automated bacterial testing device RAISUS S4

ObjectiveWe investigated a rapid detection method for carbapenemase-producing gram-negative bacilli (CP-GNR) using meropenem (MEPM) to assess the efficiency of the antimicrobial susceptibility testing. MethodsWe used the function that can monitor the growth curve with the resistant bacteria monitoring function (RAISUS S4). Rapid detection of CP-GNR was performed using RAISUS S4 in two types of antimicrobial susceptibility testing, the RAISUS 18-hour method (18-h method) and RAISUS rapid method (rapid method) for Enterobacterales (F-GNR) and non-fermenting gram-negative bacilli (NF-GNR). ResultsWhen F-GNR were based on MEPM MIC ≥ 0.25 µg/mL, CP-GNR were detected with a sensitivity of 100% (58/58) for the 18-h method and 98.3% (57/58) for the rapid method; the shortest detection times were 5.3 and 4.0 h, respectively. When NF-GNR were based on MEPM MIC > 8 µg/mL, it was possible to detect CP-GNR with 100% sensitivity (58/58) in both methods. Furthermore, in the analysis using the 18-h method for monitoring resistant bacteria, when ≥ 2 µg/mL was used as the screening concentration for F-GNR, approximately 50% of the resistant genotypes, NDM, GES, and KPC, were detected in approximately 7 h However, detecting the IMP and VIM took 11–12 h ConclusionsThe 18-h and rapid methods with RAISUS S4 were highly correlated with the results of the microdilution method of CLSI, and CP-GNR detection was rapid using a function that can monitor the growth curve with RAISUS S4.

Bloodstream infections in a Brazilian Pediatric Tertiary Oncology Hospital: 30-month analysis regarding the classification of the infection, distribution of microorganisms and their resistance profile

Abstract Background Infections are a major cause of morbidity and mortality in pediatric oncology patients during their treatment. Bloodstream infections are the main site of infection in these patients. Bacteremia in these patients can be secondary to a primary infectious focus, result from central line associated bloodstream infections (CLABSIs) or mucosal barrier injury laboratory-confirmed bloodstream infection (MBI-LCBI). Methods Descriptive study of bloodstream infections in pediatric patients undergoing oncological treatment and hematopoietic stem cell transplantation in a tertiary pediatric oncology hospital in Brazil from January 1st, 2021 to June 30th, 2023. Infections were classified according to the Centers for Disease Control and Prevention/ National Healthcare Safety Network (CDC/NHSN) criteria into CLABSIs, MBI-LCBIs and secondary bloodstream infections. Among the bloodstream infections that met CDC/NHSN criteria for CLABSI, were analyzed separately those who also met the criteria of catheter-related bloodstream infection (CRBSI) according to Infectious Diseases Society of America (IDSA). Results During this period were diagnosed 335 episodes of bloodstream infection (123 episodes in 2021, 150 in 2022 and 62 episodes in the first 6 months of 2023). There were 378 microorganisms isolated. These infections were classified into: 35% CLABSIs, 27% MBI-LCBIs, 23% CRBSIs, and 15% secondary bloodstream infections. Among the CLABSIs, the most common microorganisms were non-fermenting gram negative bacilli (NFGNB) 38%, enterobacteriaceae 35% and coagulase-negative staphylococcus (CoNS) 11%. Between CRBSIs, there were 31% enterobacteriaceae, 22% CoNS and 19% NFGNB. Among the MBI-LCBIs there were 66% enterobacteriaceae and 23% group viridans streptococci (VGS). Streptococcus pneumoniae (33%) was the most common microorganism in secondary infections followed by Staphylococcus aureus (17%). Assessing all infections together, the main enterobacteriaceae were Klebsiella spp. (40%) and only 50% of them were sensitive to cefepime while 10% were carbapenems resistant. Among NFGNB, 13% of Pseudomonas spp. and 5% of Acinetobacter spp. were carbapenems resistant. Between the gram-positive bacteria, 77% of the S. aureus were methicillin sensitive, the same percentage of the VGS were sensitive to cefepime. Conclusion Among bloodstream infections, there were a predominance of CLABSI followed by MBI-LCBIs. Antimicrobial resistance between gram-positive bacteria, is of little concern in our institution. In the case of gram-negative bacteria, resistance to cefepime is becoming worrying among enterobacteriaceae.

Review of Association Between Urinary Tract Infections and Immunosuppressive Drugs after Heart Transplantation.

Management of infections in heart transplant recipients is complex and crucial. In this population, there is a need for a better understanding of immunosuppressive trough levels (C0), infectious complications, and urinary tract infections (UTIs). The purpose of this review was to understand the association between immunosuppressive trough levels and UTIs after heart transplantation. A review of scientific literature (n= 100) was conducted based on the topic of interest by searching PUBMED.Gov (https://pubmed.ncbi.nlm.nih.gov/), Web of Science, and Scopus. The analysis of bacterial pulmonary infection required the occurrence of new or deteriorating pulmonary infiltrates and the development of organisms in cultures of sputum specimens. The diagnosis of UTIs was based on the result of related signs, pyuria, and a positive urine culture. The incidence of UTIs was reported as 0.07 episodes/1000 regarding heart transplantation days. An eightfold increase in the rate of rejection was noted in heart transplant recipients with higher variability in tacrolimus C0. There are associations between C0 of immunosuppressive drugs and clinical presentation of infection complications. Recipients with a low metabolism of immunosuppressive drugs are more susceptible to infectious complications. Attention to the biology of herpes viruses, Escherichia coli, Enterococcus spp., Pseudomonas aeruginosa, and Staphylococcus saprophyticus after heart transplantation are important, in which some of them are the most common pathogens responsible for UTIs. Pneumocystis and cytomegalovirus affect all transplant recipients. Pneumonia due to bacterial, viral, protozoa, and fungal infections, in addition to UTIs, are more specific reported types of infections in heart transplant recipients. Bacterial infections produced by extensively drug-resistant Enterobacteriaceae, vancomycin-resistant enterococci, and non-fermenting gramnegative bacteria were reported to increase after transplantation.

Genomic characterization of an uncommon Delftia acidovorans isolate obtained from aBulgarian immunocompetent outpatient diagnosed with bronchitis.

Delftia acidovorans is an aerobic, non-fermenting Gram-negative bacterium (NFGNB), found in soil, water and hospital environments. It is rarely clinically significant, most commonly affecting hospitalized or immunocompromised patients. The present study aimed to explore the genomic characteristics of a Bulgarian clinical D. acidovorans isolate (designated Dac759) in comparison to all strains of this species with available genomes in the NCBI Genome database (n = 34). Dac759 was obtained in 2021 from the sputum of a 65-year-old female immunocompetent outpatient with bronchitis. Species identification using MALDI-TOF mass spectrometry, antimicrobial susceptibility testing, whole-genome sequencing (WGS), and phylogenomic analysis were performed. The isolate demonstrated high-level resistance to colistin (16 mg L-1); resistance to gentamicin; reduced susceptibility to piperacillin, piperacillin-tazobactam, ceftazidime, cefepime, ciprofloxacin, and levofloxacin; and susceptibility to imipenem, meropenem, amikacin, and tobramycin. The observed genome size (6.43 Mb) and GC content (66.76%) were comparable with the accessible data from sequenced D. acidovorans genomes. A limited number of resistance determinants were identified in the assembled genome as follows: blaOXA-459, emrE, oqxB, and mexCD-oprJ. The phylogenomic analysis indicated a high heterogenicity of the included D. acidovorans genomes. In conclusion, to the best of our knowledge, this is the first documented case of a clinically relevant D. acidovorans isolate in Bulgaria. Unlike the majority of reports in the literature, Dac759 affected a patient with no malignancies or other preexisting comorbidities. With this in mind, its genome sequence is a valuable resource for the fundamental study of uncommon bacterial pathogens of public health importance.

Central venous catheter-related infection: does insertion site still matter? A French multicentric cohort study.

We aim to evaluate the association between central venous catheter (CVC) insertion site and microbiological CVC complications in a nationwide cohort. This study was conducted using the healthcare-associated infection surveillance cohort "REA-REZO" involving 193 intensive care units (ICUs). All CVC inserted and removed during the same ICU stay between January 1st 2018 and December 31st 2022 were eligible but only those whose tips were sent for microbiological analysis were included. Primary objective was to describe CVC insertion sites and subsequent catheter-related bloodstream infection (CRBSI). Out of 126,997 CVCs, 71,314 were not sent for tip culture, and only 55,663 CVCs were included, (30,548 in internal jugular [IJ], 14,423 in femoral and 10,692 in subclavian [SC] sites). The incidence of CRBSI was 0.7 [0.6-0.8] in the IJ site, 0.7 [0.6-0.9] in the femoral site, and 0.6 [0.4-0.7] CRBSI per 1000 CVC days in the SC site (p = 0.248). The multivariable Poisson regression model showed no differences of CRBSI incidence rates between the three insertion sites. Microorganisms observed in CRBSI were coagulase-negative Staphylococci (27.9%), Enterobacterales (27.5%), non-fermenting Gram-negative Bacilli (10.4%), Candida sp. (16.9%), and Staphylococcus aureus (16.9%). Low CRBSI incidence rates were reported. CRBSI incidences rates were similar in the three insertion sites. Uncertainty remains due to potential selection bias since many CVCs had to be excluded.

The role of non-fermenting gram-negative bacteria Stenotrophomonas maltophilia in the etiology of infectious diseases (review)

Gram-negative bacteria Stenotrophomonas maltophilia rank third among non-fermenting gram-negative bacteria in terms of detection frequency in various infectious pathologies. This review presents information on the various virulence factors, mechanisms used by S. maltophilia for colonization and infection of the human body, multiple drug resistance, clinical manifestations of the diseases caused, and methods of bacteriological diagnosis. The importance of early identification of this pathogen for practicing physicians is emphasized. The selection of treatment for infections caused by S. maltophilia is discussed, highlighting the challenges faced by both clinicians and microbiologists. To this end, current domestic and international scientific publications were reviewed using scientific electronic library search engines such as PubMed, Google Scholar, eLIBRARY.ru, and CyberLeninka.

A Five-Year Trend Analysis of Antibacterial Resistance Patterns Among Non-fermenting Gram-Negative Bacilli: A Retrospective Study From the ICU Settings of a Tertiary Care Hospital.

Non-fermenting gram-negative bacilli (NFGNB) infections have emerged as a serious health concern in ICUs. Multi-drug resistant (MDR) strains of NFGNB can evolve by acquiring resistance genes to at least one agent in three or more antibacterial categories. This study aimed to analyse the prevalence of NFGNB, the distribution of MDR strains, and antibiotic resistance trends of NFGNB in different ICUs of a tertiary care hospital over a period of five years. This retrospective study was conducted in a tertiary care teaching hospital in eastern India, including a total of 20,256 samples received from various ICUs over five years. Data retrieved from the Laboratory Information System (LIS) of the hospital, and repetitive isolates from the same patients, were excluded. All samples were processed according to standard microbiological protocols by automated systems. Data were entered into a Microsoft Excel spreadsheet (Microsoft® Corp., Redmond, WA, USA), analysed using Epi Info software, and presented using descriptive statistics. Chi-square and Fisher's exact tests (where appropriate) were used as tests of significance, with a p-value of <0.05 considered statistically significant. A total of 18,032 culture-positive samples out of 20,256 samples showed growth of 18,659 bacteria. Out of these, 952 isolates were NFGNB. The prevalence of NFGNB was found to be 5.10% among all isolated bacteria. The predominant sources were respiratory samples (37.3%). Acinetobacter spp. emerged as the most prevalent NFGNB (46.5%), followed by Pseudomonas spp. (31%) and Burkholderia spp. (14.3%). Among the NFGNB isolates, 61.76% exhibited MDR, with the highest prevalence of MDR strains seen in Elizabethkingia spp. (94.7%). Among the most prevalent NFGNB, Acinetobacter spp., 64.8% were MDR strains. Trend analysis of antibiotic resistance patterns of Acinetobacter spp. indicated a substantial increase for trimethoprim-sulfamethoxazole by 18.5%, minocycline (44.4%), amikacin (20.4%), and ceftazidime (7.4%), whereas there was a reduced trend in resistance to carbapenems (6.5%), ciprofloxacin (4.7%), and cefepime (3.7%) over five years. In Pseudomonas spp., resistance to meropenem increased by 17.4%, and for ceftazidime (11.8%), amikacin (10.6%), and piperacillin-tazobactam (7.9%), whereas resistance to aztreonam diminished by 13.9%. Burkholderia spp. exhibited a 23.5% escalation in resistance to meropenem and ceftazidime (5.9%), while resistance to levofloxacin experienced a decrease of 30.2%. The study showed the prevalence of various NFGNB as 5.10% in ICU settings, with Acinetobacter spp. (46.5%) being the most common isolated bacteria. Notably, 61.76% of the isolates were MDR. Antibiotic trend analysis over five years showed increasing resistance of Acinetobacter spp. to trimethoprim-sulfamethoxazole, minocycline, and ceftazidime, with improved susceptibility for carbapenems, ciprofloxacin, and cefepime. Pseudomonas spp. showed increased susceptibility to aztreonam and rising resistance for meropenem, piperacillin-tazobactam, ceftazidime, and amikacin. In Burkholderia spp., there was increased susceptibility to levofloxacin and rising resistance to meropenem and ceftazidime. These findings focus on the need for vigilant antibiotic stewardship, with the adoption of appropriate infection prevention and control practices to restrict the emergence and spread of MDR NFGNB infections in ICU settings of hospitals.

Drug Resistance in Biofilm and Planktonic Cells of Achromobacter spp., Burkholderia spp., and Stenotrophomonas maltophilia Clinical Isolates.

Background: Biofilm production in nonfermenting Gram-negative bacteria influences drug resistance. The aim of this work was to evaluate the effect of different antibiotics on biofilm eradication of clinical isolates of Achromobacter, Burkholderia, and Stenotrophomonas maltophilia. Methods: Clinical isolates were identified by matrix-assisted laser desorption ionization-time of flightmass spectrometry in a third-level hospital in Monterrey, Mexico. Crystal violet staining was used to determine biofilm production. Drug susceptibility testing was determined by broth microdilution in planktonic cells and biofilm cells. Results: Resistance in planktonic cells was moderate to trimethoprim-sulfamethoxazole, and low to chloramphenicol, minocycline, levofloxacin (S. maltophilia and Burkholderia), ceftazidime, and meropenem (Burkholderia and Achromobacter). Biofilm eradication required higher drug concentrations of ceftazidime, chloramphenicol, levofloxacin, and trimethoprim-sulfamethoxazole than planktonic cells (p < 0.05). Levofloxacin showed biofilm eradication activity in S. maltophilia, minocycline and meropenem in Burkholderia, and meropenem in Achromobacter. Conclusions: Drug resistance increased due to biofilm production for some antibiotics, particularly ceftazidime and trimethoprim-sulfamethoxazole for all three pathogens, chloramphenicol for S. maltophilia and Burkholderia, and levofloxacin for Burkholderia. Some antibiotics could be used for the treatment of biofilm-associated infections in our population, such as levofloxacin for S. maltophilia, minocycline and meropenem for Burkholderia, and meropenem for Achromobacter.