Multidrug-resistant bacteria in solid organ transplant recipients

Incidence, risk factors and clinical outcome of multidrug-resistant organisms after heart transplantation

BACKGROUND

Transplant recipients commonly harbor multidrug-resistant organisms (MDROs), as a result of frequent hospital admissions and increased exposure to antimicrobials and invasive procedures.

AIM

To investigate the impact of patient demographic and clinical characteristics on MDRO acquisition, as well as the impact of MDRO acquisition on intensive care unit (ICU) and hospital length of stay, and on ICU mortality and 1-year mortality post heart transplantation.

METHODS

This retrospective cohort study analyzed 98 consecutive heart transplant patients over a ten-year period (2013-2022) in a single transplantation center. Data was collected regarding MDROs commonly encountered in critical care.

RESULTS

Among the 98 transplanted patients (70% male), about a third (32%) acquired or already harbored MDROs upon transplantation (MDRO group), while two thirds did not (MDRO-free group). The prevalent MDROs were Acinetobacter baumannii (14%), Pseudomonas aeruginosa (12%) and Klebsiella pneumoniae (11%). Compared to MDRO-free patients, the MDRO group was characterized by higher body mass index (P = 0.002), higher rates of renal failure (P = 0.017), primary graft dysfunction (10% vs 4.5%, P = 0.001), surgical re-exploration (34% vs 14%, P = 0.017), mechanical circulatory support (47% vs 26% P = 0.037) and renal replacement therapy (28% vs 9%, P = 0.014), as well as longer extracorporeal circulation time (median 210 vs 161 min, P = 0.003). The median length of stay was longer in the MDRO group, namely ICU stay was 16 vs 9 d in the MDRO-free group (P = 0.001), and hospital stay was 38 vs 28 d (P = 0.006), while 1-year mortality was higher (28% vs 7.6%, log-rank-χ 2: 7.34).

CONCLUSION

Following heart transplantation, a predominance of Gram-negative MDROs was noted. MDRO acquisition was associated with higher complication rates, prolonged ICU and total hospital stay, and higher post-transplantation mortality.

Diagnosing and Managing Urinary Tract Infections in Kidney Transplant Recipients

In the article, the authors review antibiotic treatment options for both acute uncomplicated UTI and complicated UTI. In addition, they review alternative regimens which are needed in the setting of drug-resistant pathogens including vancomycin-resistant Enterococcus, -extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E), carbapenem-resistant Enterobacterales, and carbapenem-resistant Pseudomonas, which are encountered with more frequency.

Effect of preservation fluid contamination and associated possible donor-derived infections on early postoperative prognosis in kidney transplant recipients

BACKGROUND

The study aims to analyze the epidemiology of preservation fluid (PF) contamination and investigate the impact of PF contamination and possible donor-derived infections(p-DDI) on early postoperative prognosis in kidney transplant (KT) recipients.

METHODS

A total of 256 PF samples were collected for microbiological evaluation from all KT recipients who received deceased donor donations in our hospital from June 2018 to August 2022. Data on the baseline and clinical characteristics of these PF corresponding to recipients and donors were extracted from the electronic medical record. It mainly included the early postoperative complications and prognosis of KT recipients.

RESULTS

From June 2018 to August 2022, 597 kidney transplants were performed in our center, with 260 recipients receiving kidney transplantation from donation after citizens' death. A total of 256 samples of PF were collected, of which 64.5% (165/256) were culture positive, and 24.6% (63/165) of the culture-positive PF were polymicrobial contamination. A total of 238 strains were isolated, of which coagulase-negative staphylococci (CoNS) had the highest proportion of 34.0% (81/238), followed by Klebsiella pneumoniae with 20.6% (49/238) and Escherichia coli with 8.8% (21/238). Recipients with culture-positive PF had a significantly higher incidence of postoperative infection (55.8% vs. 20.9%, P < 0.001) and DGF (38.2% vs. 24.2%, P = 0.023). In addition, the incidence of p-DDI was 12.9% (33/256). CRKP was the most common pathogen causing p-DDI. The recipients who developed p-DDI had a higher rate of graft loss (9.1% vs. 0.4%, P < 0.001), mortality (12.1% vs. 3.1%, P = 0.018), and longer postoperative hospital stay (30 days (19.5-73.5) vs. (22 days (18-32), P < 0.05) compared with recipients who did not develop p-DDI.

CONCLUSIONS

Culture-positive PF is potentially significant for KT recipients, and p-DDI may increase the risk of poor prognosis for recipients. Prophylactic anti-infective treatment should be actively performed for highly virulent or multidrug-resistant (MDR) pathogens (especially Carbapenem-resistant Klebsiella pneumoniae, CRKP) in PF to avoid the occurrence of p-DDI.

Efficacy and safety of carrimycin in ten patients with severe pneumonia following solid organ transplantation

BACKGROUND

The number of patients undergoing solid organ transplantation has increased annually. However, infections in solid organ transplant recipients can have a severe effect on patient survival owing to the continued use of immunosuppressants. Carrimycin is a novel macrolide antibiotic produced by genetically engineered streptomyces spiramyceticus harboring a 4''-O-isovaleryltransferase gene (ist) from streptomyces thermotoleran. Carrimycin has good antibacterial and antiviral effects. However, no relevant studies have been conducted on the efficacy and safety of carrimycin in patients with severe pneumonia (SP) after solid organ transplantation.

AIM

To explore the efficacy and safety of carrimycin in patients with SP after solid organ transplantation to provide a medication reference for clinical treatment.

METHODS

In March 2022, ten patients with SP following solid-organ transplantation were treated at our hospital between January 2021 and March 2022. When the condition was critical and difficult to control with other drugs, carrimycin was administered. These ten patients' clinical features and treatment protocols were retrospectively analyzed, and the efficacy and safety of carrimycin for treating SP following solid organ transplantation were evaluated.

RESULTS

All ten patients were included in the analysis. Regarding etiological agent detection, there were three cases of fungal pneumonia, two cases of bacterial pneumonia, two cases of Pneumocystis pneumonia, and three cases of mixed infections. After treatment with carrimycin, the disease in seven patients significantly improved, the course of the disease was significantly shortened, fever was quickly controlled, chest computed tomography was significantly improved, and oxygenation was significantly improved. Finally, the patients were discharged after curing. One patient died of acute respiratory distress syndrome, and two patients discontinued treatment.

CONCLUSION

Carrimycin is a safe and effective treatment modality for SP following solid organ transplantation. Carrimycin may have antibacterial and antiviral effects in patients with SP following solid organ transplantation.

Klebsiella pneumoniae infections after liver transplantation: Drug resistance and distribution of pathogens, risk factors, and influence on outcomes

BACKGROUND

Liver transplantation (LT) is the only curative treatment for end-stage liver disease. However, LT recipients are susceptible to infection, which is the leading cause of early mortality after LT. Klebsiella pneumoniae infections (KPIs) in the bloodstream are common in LT recipients. We hypothesized that KPIs and carbapenem-resistant Klebsiella pneumoniae (CRKP) infections may affect the outcomes of LT recipients.

AIM

To assess KPI incidence, timing, distribution, drug resistance, and risk factors following LT and its association with outcomes.

METHODS

This retrospective study included 406 patients undergoing LT at The Third Xiangya Hospital of Central South University, a tertiary hospital, from January 2015 to January 2023. We investigated the risk factors for KPIs and assessed the impact of KPIs and CRKP infections on the prognosis of LT recipients using logistic regression analysis.

RESULTS

KPI incidence was 7.9% (n = 32), with lung/thoracic cavity the most frequent site of infection; the median time from LT to KPI onset was 7.5 d. Of 44 Klebsiella pneumoniae isolates, 43 (97.7%) and 34 (77.3%) were susceptible to polymyxin B or ceftazidime/avibactam and tigecycline, respectively; > 70% were resistant to piperacillin/ tazobactam, ceftazidime, cefepime, aztreonam, meropenem, and levofloxacin. Female sex [odds ratio (OR) = 2.827, 95% confidence interval (CI): 1.256-6.364; P = 0.012], pre-LT diabetes (OR = 2.794, 95%CI: 1.070-7.294; P = 0.036), day 1 post-LT alanine aminotransferase (ALT) levels ≥ 1500 U/L (OR = 3.645, 95%CI: 1.671-7.950; P = 0.001), and post-LT urethral catheter duration over 4 d (OR = 2.266, 95%CI: 1.016-5.054; P = 0.046) were risk factors for KPI. CRKP infections, but not KPIs, were risk factors for 6-month all-cause mortality post-LT.

CONCLUSION

KPIs occur frequently and rapidly after LT. Risk factors include female sex, pre-LT diabetes, increased post-LT ALT levels, and urethral catheter duration. CRKP infections, and not KPIs, affect mortality.

Tobramycin Systemic Absorption in Lung Transplant Recipients Treated With Inhaled Tobramycin: A Cohort Study

Inhaled tobramycin treatment has been associated with nephrotoxicity in some case reports, but limited data are available about serum levels and its possible systemic absorption in lung transplant recipients (LTR). We conducted a single-center, observational and retrospective study of all adult (>18 years old) LTR treated with inhaled tobramycin for at least 3 days between June 2019 and February 2022. Trough serum levels were collected and >2 μg/mL was considered a high drug level. The primary outcome assessed the presence of detectable trough levels, while the secondary outcome focused on the occurrence of acute kidney injury (AKI) in individuals with detectable trough levels. Thirty-four patients, with a median age of 60 years, were enrolled. The primary indications for treatment were donor bronchial aspirate bacterial isolation (18 patients) and tracheobronchitis (15 patients). In total, 28 patients (82%) exhibited detectable serum levels, with 9 (26%) presenting high levels (>2 μg/mL). Furthermore, 9 patients (26%) developed acute kidney injury during the treatment course. Median trough tobramycin levels were significantly elevated in invasively mechanically ventilated patients compared to non-ventilated individuals (2.5 μg/mL vs. 0.48 μg/mL) (p < 0.001). Inhaled tobramycin administration in LTRs, particularly in those requiring invasive mechanical ventilation, may result in substantial systemic absorption.

Gram-negative bacterial colonizations before bilateral lung transplant. The impact of 'targeted' versus 'standard' surgical prophylaxis

BACKGROUND

Infections are one of the most common causes of death after lung transplant (LT). However, the benefit of 'targeted' prophylaxis in LT recipients pre-colonized by Gram-negative (GN) bacteria is still unclear.

METHODS

All consecutive bilateral LT recipients admitted to the Intensive Care Unit of the University Hospital of Padua (February 2016-2023) were retrospectively screened. Only patients with pre-existing GN bacterial isolations were enrolled and analyzed according to the antimicrobial surgical prophylaxis ('standard' vs. 'targeted' on the preoperative bacterial isolation).

RESULTS

One hundred eighty-one LT recipients were screened, 46 enrolled. Twenty-two (48%) recipients were exposed to 'targeted' prophylaxis, while 24 (52%) to 'standard' prophylaxis. Overall prevalence of postoperative multi-drug resistant (MDR) GN bacteria isolation was 65%, with no differences between the two surgical prophylaxis (p = 0.364). Eleven (79%) patients treated with 'standard' prophylaxis and twelve (75%) with 'targeted' therapy reconfirmed the preoperative GN pathogen (p = 0.999). The prevalence of postoperative infections due to MDR GN bacteria was 50%. Of these recipients, 4 belonged to the 'standard' and 11 to the 'targeted' prophylaxis (p = 0.027).

CONCLUSIONS

The administration of a 'targeted' prophylaxis in LT pre-colonized recipients seemed not to prevent the occurrence of postoperative MDR GN infections.

New Antibiotics Against Multidrug-Resistant Gram-Negative Bacteria in Liver Transplantation: Clinical Perspectives, Toxicity, and PK/PD Properties

Antimicrobial resistance is a growing global health problem, and it is especially relevant among liver transplant recipients where infections, particularly when caused by microorganisms with a difficult-to-treat profile, are a significant cause of morbidity and mortality. We provide here a complete dissection of the antibiotics active against multidrug-resistant Gram-negative bacteria approved over the last years, focusing on their activity spectrum, toxicity profile and PK/PD properties, including therapeutic drug monitoring, in the setting of liver transplantation. Specifically, the following drugs are presented: ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam, cefiderocol, and eravacycline. Overall, studies on the safety and optimal employment of these drugs in liver transplant recipients are limited and especially needed. Nevertheless, these pharmaceuticals have undeniably enhanced therapeutic options for infected liver transplant recipients.

A metagenomic prospective cohort study on gut microbiome composition and clinical infection in small bowel transplantation

Two-thirds of small-bowel transplantation (SBT) recipients develop bacteremia, with the majority of infections occurring within 3 months post-transplant. Sepsis-related mortality occurs in 31% of patients and is commonly caused by bacteria of gut origin, which are thought to translocate across the implanted organ. Serial post-transplant surveillance endoscopies provide an opportunity to study whether the composition of the ileal and colonic microbiota can predict the emergence as well as the pathogen of subsequent clinical infections in the SBT patient population. Five participants serially underwent aspiration of ileal and colonic bowel effluents at transplantation and during follow-up endoscopy either until death or for up to 3 months post-SBT. We performed whole-metagenome sequencing (WMS) of 40 bowel effluent samples and compared the results with clinical infection episodes. Microbiome composition was concordant between participants and timepoint-matched ileal and colonic samples. Four out of five (4/5) participants had clinically significant infections thought to be of gut origin. Bacterial translocation from the gut was observed in 3/5 patients with bacterial infectious etiologies. In all three cases, the pathogens had demonstrably colonized the gut between 1-10 days prior to invasive clinical infection. Recipients with better outcomes received donor grafts with higher alpha diversity. There was an increase in the number of antimicrobial resistance genes associated with longer hospital stay for all participants. This metagenomic study provides preliminary evidence to support the pathogen translocation hypothesis of gut-origin sepsis in the SBT cohort. Ileal and colonic microbiome compositions were concordant; therefore, fecal metagenomic analysis could be a useful surveillance tool for impeding infection with specific gut-residing pathogens.

Antimicrobial Stewardship in Immunocompromised Patients: Current State and Future Opportunities

Immunocompromised (IC) patients are high risk for complications due to a high rate of antibiotic exposure. Antimicrobial stewardship interventions targeted to IC patients can be challenging due to limited data in this population and a high risk of severe infection-related outcomes. Here, the authors review immunocompromised antimicrobial stewardship barriers, metrics, and opportunities for antimicrobial use and testing optimization. Last, the authors highlight future steps in the field.

A joint program of antimicrobial stewardship and hospital-acquired infection control to reduce healthcare-associated infections after kidney transplantation: The Hipomenes study

Infection is a common complication in kidney transplant recipients (KTRs). The usefulness of antimicrobial stewardship programs (ASP) and hospital-acquired infection control (HAIC) initiatives in the general inpatient population is well established. We performed a quasi-experimental study to evaluate a joint ASP/HAIC initiative focused on KTRs. A dedicated ASP team optimized antimicrobial prescriptions in consecutive KTRs during the intervention period (June 2015-March 2016). A multifaceted, evidence-based HAIC program was concurrently implemented. Results were compared with the preceding period (June 2014-March 2015). We included 96 and 100 KTRs in the intervention and preintervention periods, respectively. There was a reduction in the consumption of meropenem (rate ratio [RR]: 0.63; 95% confidence interval [CI]: 0.53-0.75; P <.0001), ceftazidime (RR: 0.31; 95% CI: 0.21-0.45; P <.0001), vancomycin (RR: 0.65; 95% CI: 0.53-0.8; P <.0001), and ciprofloxacin (RR: 0.66; 95% CI: 0.55-0.81; P <.0001) and an increase of fosfomycin (RR: 1.80; 95% CI: 1.17-2.76; P =.008) during the intervention period. The incidence of cystitis (RR: 0.30; 95% CI: 0.28-0.33; P <.001) and upper urinary tract infection (RR: 0.56; 95% CI: 0.33-0.95; P =.04) decreased. A specific ASP/HAIC initiative was effective in optimizing antimicrobial use and reducing the incidence of common bacterial infections among KTRs.

Peri-transplant Treatment with Ceftaroline in Kidney Transplant Recipients at Risk of Donor-derived MRSA Infections: A Case Series

The rising prevalence of MDR pathogens has a significant impact on the recipients' outcome, as this increases the risk of graft complications and makes the management of the peri-transplant phase more difficult. Among the different MDR germs, Methicillin-resistant Staphylococcus aureus (MRSA) represents one of the most frequently isolated pathogens. We report for the first time the off-label use of Ceftaroline in six kidney transplant recipients with donor peritransplantation MRSA bacteremia at the Division of Kidney Transplant Unit of Federico II University Hospital of Naples, Italy, between September and December 2022. Each patient was followed up for the next three months after transplantation, monitoring the clinical and laboratory outcome, the risk of infection, and the efficacy and safety profile of the treatment performed. In the subsequent three months of follow-up to the transplant, none of the six patients showed donor-related infections. In particular, none of the six patients showed MRSA bacteremia or other related MRSA infections. In conclusion, our real-life experience shows that Ceftaroline could represent a valid therapeutic option in the management of solid organ transplant patients with a risk of donor-derived MRSA infection. However, despite the few cases considered, this approach deserves further investigation in ad hoc studies or clinical trials due to our positive results.

Investigating infectious outcomes in adult patients undergoing solid organ transplantation: A retrospective single-center experience, Paris, France

OBJECTIVES

This study described the demographic characteristics, clinical presentation, treatment, and outcomes of solid organ transplant recipients who were admitted to our center for infection. It also determined factors associated with a poor outcome, and compares early and late period infections.

METHODS

In this retrospective observational study, conducted at a tertiary care center in France between October 2017 and March 2019, infectious outcomes of patients with solid organ transplant where studied.

RESULTS

A total of 104 patients were included with 158 hospitalizations for infection. Among these 104 patients, 71 (68%) were men. The median age was 59 years old. The most common symptoms on admission were fever (66%) and chills (31%). Lower respiratory tract infections were the most common diagnosis (71/158 hospitalizations). Urinary tract infections were frequently seen in kidney transplant recipients (25/60 hospitalizations). One or more infectious agents were isolated for 113 hospitalizations (72%): 70 bacteria, 36 viruses and 10 fungi, with predominance of gram-negative bacilli (53 cases) of which 13 were multidrug-resistant. The most frequently used antibiotics were third generation cephalosporins (40 cases), followed by piperacillin-tazobactam (26 cases). We note that 25 infections (16%) occurred during the first 6 months (early post-transplant period). Patients admitted during the early post-transplant period were more often on immunosuppressive treatment with prednisone (25/25 VS 106/133) (p = 0.01), mycophenolic acid (22/25 VS 86/133) (p = 0.03), presented for an urinary tract infection (10/25 VS 25/133) (p = 0.04) or a bacterial infection (17/25 VS 53/133) (p = 0.01). Patients with later infection had more comorbidities (57/83 VS 9/21) (p = 0.03), cancer (19/83 VS 0/21) (p = 0.04) or were on treatment with everolimus (46/133 VS 0/25) (p = 0.001). During 31 hospitalizations (20%), patients presented with a serious infection requiring intensive care (n = 26; 16%) or leading to death (n = 7; 4%). Bacteremia, pulmonary and cardiac complications were the main risk factors associated with poor outcome.

CONCLUSION

Infections pose a significant challenge in the care of solid organ transplant patients, particularly those with comorbidities and intensive immunosuppression. This underscores the crucial importance of continuous surveillance and epidemiologic monitoring within this patient population.

Colonization of extended-spectrum β-lactamase-producing Enterobacteriaceae does not affect subsequent infection and liver transplant outcomes: a retrospective observational cohort study

Objective

To investigate the colonization rate of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E), subsequent infections by ESBL-E and ESBL-producing gram-negative bacilli (ESBL-GNB), and the effect of ESBL-E colonization on clinical outcomes in liver transplantation (LT) recipients.

Methods

This is a retrospective cohort study that included patients who underwent LT at Shanghai Renji Hospital between July 2016 and December 2017. Rectal swabs from LT patients at the postoperative ICU enrollment were screened anonymously for ESBL-E carriage. Demographics data, laboratory indexes, operative complications, and clinical course information were also obtained. The extent of ESBL-E colonization, the subsequent infection rates of ESBL-E and ESBL-GNB, and the clinical outcomes were compared between ESBL-E colonized and non-colonized patients.

Results

In total, 496 liver transplant recipients (387 males) were included in this study. ESBL-E colonization was detected in 240 patients (48.4%). There was no significant difference between the rates of ESBL-E infection (5.8 vs. 3.1%, p = 0.143), Ischemia-reperfusion ≥ 3 (27.9 vs. 24.6%, p = 0.403), acute kidney injury (39.6 vs. 38.7%, p = 0.835), acute rejection (2.1 vs. 1.6%, p = 0.664), graft versus host reaction (1.3 vs. 1.2%, p = 0.937), duration of hospitalization (22 vs. 23 days, p = 0.568), 90-day mortality (7.1 vs. 4.7%, p = 0.262) and 1-year mortality (12.9 vs. 9.3%, p = 0.265) in patients with and without ESBL-E colonization. Though the ESBL-GNB infection rate was higher in ESBL-E colonized patients (12.1 vs. 6.6%, p = 0.037), multivariate analysis showed that ESBL-E colonization did not increase the risk of ESBL-GNB infection (Model 1: aOR 1.755, 95% CI: 0.911-3.380, p = 0.093; Model 2: aOR 1.556, 95% CI: 0.761-3.181, p = 0.226). The ESBL-producing bacteria spectrum of colonization was significantly different from that of infections occurring after LT, with only three colonization events leading to infection by the same pathogen identified.

Conclusion

ESBL-E colonization in liver transplant patients is not associated with ESBL-E infection, nor is it a risk factor for post-transplant ESBL-GNB infection. Additionally, ESBL-E colonization does not lead to worse prognoses when compared with non-colonized patients.

Clinical trial registration

Chinese Clinical Trial Registry, Identifier [ChiCTR2100043034].

Treatment of Asymptomatic Bacteriuria after Kidney Transplantation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background and Objectives: Asymptomatic bacteriuria (ASB) is prevalent in kidney transplant recipients (KTRs) and is hypothesized to heighten the risk of subsequent urinary tract infections (UTIs). Whether antibiotic treatment of ASB in KTRs is beneficial has not been elucidated. Materials and Methods: We carried out a systematic review and meta-analysis of all randomized controlled trials (RCTs) and quasi-RCTs that examined the merits of managing asymptomatic bacteriuria in KTRs. The primary outcomes were rates of symptomatic urinary tract infections (UTIs) and antimicrobial resistance. Results: Five studies encompassing 566 patients were included. No significant difference in symptomatic UTI rates was found between antibiotics and no treatment groups (relative risk (RR) 1.05, 95% confidence interval (CI) = 0.78-1.41), with moderate heterogeneity (I2 = 36%). Antibiotic treatment was found to present an uncertain risk for the development of drug-resistant strains (RR = 1.51, 95% CI = 0.95-2.40, I2 = 0%). In all trials, no significant difference between study arms was demonstrated regarding patient and graft outcomes, such as graft function, graft loss, hospitalization due to UTI, all-cause mortality, or acute rejection. Conclusions: The practice of screening and treating kidney transplant patients for asymptomatic bacteriuria does not curtail the incidence of future symptomatic UTIs, increase antimicrobial resistance, or affect graft outcomes. Whether early treatment of ASB after kidney transplantation (<2 months) is beneficial requires more RCTs.

Multidrug-resistant organisms in lung transplant: a narrative review

PURPOSE OF REVIEW

The purpose of this narrative review is presenting the current knowledge of multidrug-resistant (MDR) pathogens in lung transplant recipients, considering both Gram-positive and Gram-negative bacteria.

RECENT FINDINGS

Overall prevalence of Gram-negative pathogens has increased remarkably (4.33/1000 recipient-days) in solid organ transplant recipients, while the prevalence of Gram-positive bacteria seems to be decreasing (0.20 cases/100 transplant-years). In lung transplant, the prevalence of postoperative infections due to MDR-GN bacteria has been assessed between 31 and 57%, and the incidence of carbapenem-resistant Enterobacterales is between 0.4 and 20%, with a related mortality up to 70%. MDR Pseudomonas aeruginosa is common in lung transplant recipients with cystic fibrosis and may contribute to bronchiolitis obliterans syndrome. The prevalence of MDR Gram-positive bacteria is around 30% (predominantly Methicillin-resistant Staphylococcus aureus and Coagulase-negative staphylococcus).

SUMMARY

Survival after lung transplant, although lower than in other SOT, is increasing and currently at 60% at 5 years. This review highlights the potential clinical and social burden of postoperative infections in lung transplant recipients, and confirmed that a PI due to MDR bacteria negatively affects survival. A prompt diagnosis, prevention and management of these MDR pathogens should remain the cornerstone for higher goals of care.

Carriage of multidrug-resistant Gram-negative bacilli: duration and risk factors

Identification of risk factors influencing the duration of carriage of multidrug-resistant Gram-negative bacilli (MDR-GNB) may be useful for infection control. The aim of this study is to estimate the impact of several factors collected for routine hospital surveillance on the duration of carriage of selected MDR-GNB. From January 2015 to July 2021, patients with at least two clinical/surveillance samples positive for MDR-GNB different from ESBL-producing E. coli or AmpC - exclusively producing Enterobacterales were assessed. Microorganisms, age, number of admissions, clinical or rectal sample, sex, and admission service were evaluated as risk factors. Multivariate analysis was performed by a Cox proportional hazard model. A total of 1981 episodes of colonization were included. Involved microorganisms were ESBL-Klebsiella pneumoniae (KP) in 1057 cases (53.4%), other ESBL-non-E. coli Enterobacterales in 91 (4.6%), OXA-48-KP in 263 (13.3%), KPC-KP in 90 (4.5%), VIM-KP in 29 (1.5%), carbapenemase-producing non-KP Enterobacterales (CP-non-KP) in 124 (6.3%), and MDR Pseudomonas aeruginosa (MDR-PAER) in 327 (16.5%). No differences in duration of colonization were observed among ESBL-KP (median colonization time 320 days), ESBL-non-E. coli Enterobacterales (226 days), OXA48-KP (305 days), and MDR-PAER (321 days). For each group, duration of colonization was significantly longer than that of KPC-KP (median colonization time 60 days), VIM-KP (138 days), and CP-non-KP (71 days). Male sex (HR = 0.88; 95% CI 0.78-0.99), detection in Hepatology-Gastroenterology (HR = 0.71; 95% CI 0.54-0.93), clinical sample (HR = 0.61; 95% CI 0.53-0.69), and > 2 admissions after first detection (HR = 0.47; 95% CI 0.42-0.52) were independent predictors of longer carriage, whereas VIM-KP (HR = 1.61; 95% CI 1.04-2.48), KPC-KP (HR = 1.85; 95% CI 1.49-2.3), and CP-non-KP (HR = 1.92; 95% CI 1.49-2.47) were associated with shorter colonization time. Duration of colonization was significantly longer for ESBL-KP, other ESBL-non-E. coli Enterobacterales, OXA-48-KP, and MDR-PAER. For these microorganisms, prolonging surveillance up to 2.5-3 years should be considered. Male sex, clinical sample, multiple readmissions, admission service, and type of microorganism are independent predictors of the duration of carriage.

Case Report: Successful Treatment of Recurrent Urinary Tract Infection Due to Extensively Drug-Resistant Klebsiella Pneumoniae in a Kidney Transplant Recipient Using Chloramphenicol

Effective therapies for multidrug-resistant (MDR) microorganisms, especially Gram-negative bacteria, are becoming rare. Also, solid-organ transplant recipients are at high risk of MDR Gram-negative bacilli infection. Urinary tract infections are the most frequent bacterial infections in kidney transplant recipients and are an important cause of mortality after renal transplantation. We describe a case of complicated urinary tract infection in a kidney transplant patient due to extensively drug-resistant (XDR) K. pneumoniae treated successfully with a regimen comprising a combination of chloramphenicol and ertapenem. We do not recommend chloramphenicol as a first-line choice for treating complicated urinary tract infections. Still, we believe it is an alternative for infections caused by MDR and/or XDR pathogens in renal transplant patients, as other options are nephrotoxic.

High rates of extensively drug-resistant Acinetobacter baumannii in a Peruvian hospital 2013–2019

Multidrug-resistant (MDR) Acinetobacter baumannii has become a major concern of hospital care. The objective of the study was to evaluate the evolution of antimicrobial resistance of A. baumannii in a Peruvian hospital from 2013 to 2019. A total of 993 A. baumannii clinical isolates were recovered. Antimicrobial resistance levels were extremely high, except for colistin. Among the remaining antibacterial agents, ampicillin plus sulbactam (AMS) was the most active (71.4% of resistance), with resistance levels to the remaining agents ranging from 75.9% to amikacin to 99.2% to ertapenem. The presence of significant differences was observed in extensively drug-resistant (XDR) A. baumannii according to samples origin. No association was observed between MDR or XDR isolates and seasonality. An impressive rate of XDR A. baumannii isolates was found, including a growing number of only-colistin-susceptible isolates highlighting the urgent need for new therapeutic alternatives.

Multidrug-Resistant and Extended-Spectrum β-Lactamase Gram-Negative Bacteria in Bilateral Lung Transplant Recipients: Incidence, Risk Factors, and In-Hospital Mortality

BACKGROUND

In recent decades, the incidence of multidrug-resistant (MDR) and extended-spectrum β-lactamase (ESBL) gram-negative (GN) bacteria has increased progressively among lung transplantation (LT) recipients. A prompt diagnosis, prevention, and management of these pathogens remain the cornerstone for successful organ transplantation.

RESEARCH QUESTION

What are the incidence of MDR and ESBL GN bacteria within the first 30 days after LT and related risk of in-hospital mortality? What are the potential clinical predictors of isolation of MDR and ESBL GN bacteria?

STUDY DESIGN AND METHODS

All consecutive LT recipients admitted to the ICU of the University Hospital of Padua (February 2016-December 2021) were screened retrospectively. Only adult patients undergoing the first bilateral LT and not requiring invasive mechanical ventilation, extracorporeal membrane oxygenation, or both before surgery were included. MDR and ESBL GN bacteria were identified using in vitro susceptibility tests and were isolated from the respiratory tract, blood, urine, rectal swab, or surgical wound or drainage according to a routine protocol.

RESULTS

One hundred fifty-three LT recipients were screened, and 132 were considered for analysis. Median age was 52 years (interquartile range, 41-60 years) and 46 patients (35%) were women. MDR and ESBL GN bacteria were identified in 45 patients (34%), and 60% of patients demonstrated clinically relevant infection. Pseudomonas aeruginosa (n = 22 [49%]) and Klebsiella pneumoniae (n = 17 [38%]) were frequently isolated after LT from the respiratory tract (n = 21 [47%]) and multiple sites (n = 18 [40%]). Previous recipient-related colonization (hazard ratio [HR], 2.48 [95% CI, 1.04-5.90]; P = .04) and empirical exposure to broad-spectrum antibiotics (HR, 6.94 [95% CI, 2.93-16.46]; P < .01) were independent predictors of isolation of MDR and ESBL GN bacteria. In-hospital mortality of the MDR and ESBL group was 27% (HR, 6.38 [95% CI, 1.98-20.63]; P < .01).

INTERPRETATION

The incidence of MDR and ESBL GN bacteria after LT was 34%, and in-hospital mortality was six times greater. Previous recipient-related colonization and empirical exposure to broad-spectrum antibiotics were clinical predictors of isolation of MDR and ESBL GN bacteria.

Role of bacteriophage therapy for resistant infections in transplant recipients

PURPOSE OF REVIEW

Multidrug-resistant organisms (MDROs) are prevalent in transplant recipients and associated with poor outcomes. We review recent cases of phage therapy used to treat recalcitrant infections in transplant recipients and explore the future role of such therapy in this setting.

RECENT FINDINGS

Individual case reports and small case series suggest possible efficacy of phage therapy for the treatment of MDRO infections in pre and posttransplant patients. Importantly, there have been no serious safety concerns in the reported cases that we reviewed. There are no applicable randomized controlled trials (RCTs) to better guide phage therapy at this time.

SUMMARY

Given the safety and possibility of successful salvage therapy of MDRO infections using bacteriophages, it is reasonable to pursue phage therapy for difficult-to-treat infections on a compassionate use basis, but RCT data are critically needed to better inform management.

Influencing mechanism of the use behavior of clinical practice guidelines on antimicrobials: evidence from the integration of theory of reasoned action and organizational readiness for change

Background

To confront the serious challenge of antimicrobial resistance, using clinical practice guidelines (CPGs) standardizing the prescription behavior is vital. However, the overall mechanisms remains largely unknown as to how guidelines' use behavior can be improved. This study aimed to identify the determinants and investigate their relationship to bridge the knowledge gap of overall influencing mechanism of the use behavior of CPGs on antimicrobials.

Methods

By integrating theory of reasoned action (TRA) and organizational readiness for change (ORC), a structured questionnaire was developed to cover potential determinants that affect physicians’ use behaviors of CPGs on antimicrobials at the individual-level (attitude, subjective norm, and behavioral intention) and organizational-level (top management support and organizational resource allocation). A multi-stage random sampling was implemented to collect data from physicians in secondary and tertiary hospitals from eastern, central and western China. Structural equation model (SEM) was used to test the proposed hypotheses, and to analyze the relationship and mechanism among the factors.

Result

In total, 815 physicians were included. Most physicians demonstrated a positive tendency toward the use of CPGs on antimicrobials, with a mean score of 3.95 (SD = 0.70). The reliability and validity analysis showed the questionnaire constructed from the integrated theoretical model of TRA and ORC was acceptable. The SEM validation results also showed that the top management support (β = 0.688, P < 0.001), organizational resource allocation (β = 0.129, P < 0.001), individual attitudes (β = 0.164, P < 0.001), subjective norms (β = 0.322, P < 0.001), and behavioral intentions (β = 0.424, P < 0.001) were positively associated with physicians’ use behaviors of CPGs on antimicrobials. Besides, top management support, organizational resource allocation, attitudes and subjective norms showed their mediating effects on regarding use behavior, which was 0.305, 0.129, 0.164 and 0.201, respectively.

Conclusions

This study revealed the influence mechanism of the use of CPGs on antimicrobials from the individual and organizational perspectives. These findings will not only help formulate future strategies to promote the use of CPGs on antimicrobials, but also provide clues for more effective prescription interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12911-022-02019-w.

Current state of antimicrobial stewardship and organ transplantation in Spain

INTRODUCTION

Solid-organ transplantation (SOT) remains the best therapeutic option for end-stage organ disease. Regrettably, SOT recipients are disproportionately affected by nosocomial infections produced by multidrug-resistant (MDR) microorganisms and antimicrobial adverse events. Both have a negative impact on the patient´s outcome.

METHODS

Description of data concerning the antimicrobial stewardship program (ASP) in SOT recipients of the University Hospital "12 de Octubre", and review of other Spanish ASPs.

RESULTS

From May 2017 to December 2021, the ASP issued 2.785 recommendations. Approximately, 4.9% were aimed at improving the antimicrobial treatment administered to SOT recipients. Treatment discontinuation or change to a better therapeutic regimen was recommended in 51.8% and 26.3% of cases, respectively. The acceptance rate of the recommendations was close to 92%. Between June 2015 and March 2016, a quasi-experimental study consisting of a joint ASP and hospital-acquired infection control (HAIC) initiative, which included kidney transplant recipients, reported a significant reduction in the consumption of meropenem, vancomycin and ciprofloxacin, and a reduction in the incidence of global bacterial infections, upper urinary tract infections, and cystitis. Although Spain has several robust regional ASPs (e.g., VINCat and PIRASOA), data specifically concerning SOT patients is lacking.

CONCLUSION

ASP coupled with HAIC programs have proven to be effective in SOT, and should be implemented in centers that perform transplantation. Since data is scarce, Spanish centers which have ASP should report their experience in SOT. Understanding the efficacy and safety of the Spanish ASP´s intervention in the SOT population is essential and deserves further study.

The Association of Organ Preservation Fluid Pathogens with Early Infection-Related Events after Kidney Transplantation

(1) Background: The need to elucidate the microbial patterns in preservation fluid and explore their relationship with early infection-related events post kidney transplant and investigate antimicrobial resistance and the effects of preemptive antibiotic therapy. (2) Methods: This retrospective study analyzed the clinical data of 514 kidney transplant donors and 808 recipients from April 2015 to October 2020. Clinical data of donor and recipient characteristics, preservation fluid microbes, early infections (≤30 days), probable donor-derived infections (P-DDIs), antimicrobial resistance and preemptive antibiotic therapy was collected. (3) Results: The incidence of bloodstream (10.3% versus 5.2%, p = 0.006) and graft-site infections (9.7% versus 4.6%, p = 0.004) was significantly higher in recipients with culture-positive preservation fluid. In addition, recipients with ESKAPE pathogens or Candida species had a notably higher rate of bloodstream infections (14.1% versus 6.9%, p = 0.033) and graft-site infections (16.7% versus 3.5%, p < 0.01) than those with other positive pathogens. Preemptive antibiotic therapy decreased the bloodstream infection rate (11.8% versus 35.7%, p = 0.047) when preservation fluid was positive for ESKAPE pathogens. (4) Conclusions: Culture-positive preservation fluid has potential implications for kidney transplant recipients. ESKAPE pathogens or Candida species in preservation fluid as well as their antimicrobial resistance properties and non-preemptive antibiotic therapy could pose a risk of early infection-related events.

Systematic review and meta-analysis of the diagnostic accuracy of procalcitonin for post-operative sepsis/infection in liver transplantation

BACKGROUND

Post-operative infection is a major cause of morbidity and mortality in Liver Transplantation (LT). Early diagnosis and antimicrobial treatment improves outcomes and ruling out sepsis aids immunosuppression decisions. Procalcitonin (PCT) has recently become part of such decision making in COVID-19 pneumonia but its role in LT is not established. We assessed the diagnostic accuracy of PCT as a diagnostic biomarker for infection or sepsis following LT.

METHODS

A systematic search was conducted for studies reporting diagnostic performance of PCT for infection/sepsis following LT. Studies were assessed for reporting of diagnostic accuracy, relevance and quality.

RESULTS

Eight studies with 363 participants reported data on the diagnostic accuracy of PCT, with pooled sensitivity, specificity, diagnostic odds ratio and summary receiver operator curve of 70% (95% CI 62-78), 77% (95% CI 73-83), 15.82 (95% CI 5.82-43.12) and 0.871 respectively. There was variability in the timing of sampling (post-operative day 1-8) and range of cut-off values (0.48 to 42.8 ng/mL). Heterogeneity was reduced when only studies with adult LT recipients were considered.

CONCLUSIONS

PCT performs moderately well as a diagnostic test for postoperative infection/sepsis following LT. This marker is more suited for use in adult LT populations.

Effects of Bacterial Urinary Tract Infection on Clinical Outcome and Survival of Kidney Transplant Patients

BACKGROUND

There is no consensus on whether the development of urinary tract infections (UTIs) leads to high mortality or graft loss in kidney transplant patients. A high incidence of multidrug resistant (MDR) infections was observed worldwide and is associated with these complications. The aim of this study was to analyze the effects of UTIs on the clinical outcome and survival in kidney transplant patients.

METHODS

This retrospective study evaluated 601 kidney transplant patients who were categorized as follows: group 1 (G1) patients without a UTI, group 2 (G2) patients with a UTI, and group 3 (G3) recipients with a recurrent UTI. Patients were followed up for at least 1 year after transplantation. Graft survival, risk of graft loss, and risk of developing a UTI were analyzed by the Kaplan-Meier method, Cox regression, and logistic regression methods, respectively. Differences with P < .05 were considered statistically significant.

RESULTS

The proportion of rejection episodes was higher in G3 (32.35%) than in G1 (20.89%) and G2 (21.88%) (P < .001). The graft survival after the 10-year follow-up was better in G1 (73.29%) than in G3 (61.62%) (P = .019). UTI recurrent episodes increased the risk of graft loss >2.5-fold. Women and those who received a kidney from a deceased donor (DD) were at risk of at least 1 UTI event during follow-up. A greater proportion of MDR infections was observed in G3 than in G2 (P < .001).

CONCLUSIONS

The risk factors for developing a UTI were female sex, receiving a DD kidney, susceptibility to other infections, episodes of rejection, and delayed graft function. Moreover, a UTI, especially a recurrent UTI, was an important risk factor for allograft loss.

Risk Factors and Outcomes of Acute Graft Pyelonephritis with Bacteremia Due to Multidrug-Resistant Gram-Negative Bacilli among Kidney Transplant Recipients

Acute graft pyelonephritis (AGP) is the leading cause of bloodstream infection in kidney transplant (KT) recipients. The prevalence of urinary tract infections caused by multidrug-resistant (MDR) Gram-negative bacilli is increasing. This 14-year prospective observational study sought to determine the clinical characteristics, risk factors, and outcomes of AGP with bacteremia due to MDR Gram-negative bacilli. Overall, 278 episodes of AGP with bacteremia due to MDR Gram-negative and non-MDR Gram-negative bacilli were identified and compared in 214 KT recipients; MDR Gram-negative bacilli were the cause in 28.4%. Overall 30-day mortality was low (1.1%). Risk factors independently associated with AGP due to MDR Gram-negative bacilli were male sex (OR 3.08; 95%CI 1.60–5.93), previous episode of bacteremic AGP (OR 2.11, 95%CI 1.09–4.09), prior antibiotic therapy in the preceding month (OR 2.47, 95%CI 1.33–4.57), and nosocomial acquisition (OR 2.03, 95%CI 1.14–3.62). Forty-three percent of MDR Gram-negative episodes received inappropriate empirical antibiotic therapy. The risk factors identified in this study may help physicians when selecting empirical antibiotic treatment for AGP. Previous antibiotic use was the main modifiable factor. Its presence highlights the importance of avoiding unnecessary antibiotics in order to bring down the high rates of MDR Gram-negative bacilli infections in this population.

Incidence, Clinicomicrobiological Characteristics, Risk Factors, and Treatment ‎Outcomes of Bacterial Infections Following Liver Transplantation in Pediatrics: A ‎Retrospective Cohort Study

Background: Liver transplantation (LT) is the definitive treatment for patients with advanced liver failure. Bacterial infections are common consequences of organ transplantation resulting from immune suppression and prolonged hospitalization. Methods: This retrospective cohort study examined the records of all liver transplant pediatrics under 18 years of age in Abu-Ali Sina hospital, Shiraz, Fars province, Iran, from April 2019 to February 2020. Demographic, laboratory, and clinical data were extracted along with the administered therapeutic approach for the patient. Results: Of 80 enrolled patients, 52 were male, and 28 were female, with a median age of 60 months. An incidence of 67.9% of bacterial infections was recorded. Gram-negative and Gram-positive pathogens accounted for 64.06% and 35.93% of infections, respectively. Surgical site infections were the most common ones. The length of ICU stay, hospitalization, mechanical ventilation duration, and re-hospitalization were significantly higher in the infected group than in non-infected pediatrics (P-value < 0.05). Multivariate regression analysis showed that the only risk factor for bacterial infections after LT was the length of ICU stay. The mortality rate was 22%, which was significantly higher among the infection group (P = 0.008). Conclusions: A high rate of bacterial infections and an increasing prevalence of nosocomial and antibiotic-resistant pathogens were detected in the early period after LT.

Epidemiology, Risk Factors and Outcome Due to Multidrug Resistant Organisms in Paediatric Liver Transplant Patients in the Era of Antimicrobial Stewardship and Screening

(1) Background: Multidrug-resistant organisms (MDRO) are a growing problem in liver transplant recipients (LTR), associated with high morbidity and mortality. We reviewed the impact of antimicrobial stewardship (AMS) and active screening of MDRO on the epidemiology and outcomes in paediatric LTR. (2) Methods: Single-centre retrospective review of paediatric LTR from January 2017 to December 2018. (3) Results: Ninety-six children were included; 32 (33%) patients were colonised with ≥1 MDRO and 22 (23%) patients had MDRO infections. Median (IQR) duration for start of infection was 9.5 (1.8−16.0) days. Colonisation rate with Gram-positive MDRO was 15.6%, with infection rate of 6.2%; majority due to Vancomycin-Resistant Enterococcus faecium (VRE). Colonisation with Gram-negative MDRO was 27.0%, with infection rate of 16.6%; majority due to extended-spectrum β-lactamase producing Enterobacteriaceae. Colonisation and infection rate due to Carbapenem-resistant Enterobacteriaceae was 6% and 3%, respectively, during screening and AMS, compared to historical control of 25% and 30%, respectively, without screening and AMS. There was significant reduction in VRE and CRE infection during AMS period in comparison to historical control. Pre-transplant risk factors including bacterial infections pre-transplant (p < 0.01), diagnosis of biliary atresia (p = 0.03), exposure to antibiotics (p < 0.01), EBV viraemia (p = 0.01), and auxiliary transplantation (p < 0.01) were associated with post-transplant MDRO infections. Patients with MDRO infections had longer length of hospital and paediatric intensive care unit stay days (p < 0.01) but associated with no mortality. (4) Conclusions: Our results demonstrate low incidence of colonisation and infections with MDRO, which were associated with high morbidity but no mortality in paediatric LTR. There was significant reduction in MRSA, VRE, and CRE during AMS period compared to pre-AMS era. Some risk factors are unavoidable but antibiotic overuse, early initiation of appropriate antibiotic therapy and effective infection prevention strategies can be monitored with multifaceted approach of AMS and screening of MDRO. With limited therapeutic options for MDRO and efficacy data of newer antibiotics in paediatric LTR, robust infection control practices are of paramount importance.

Bacterial and fungal co-infections with SARS-CoV-2 in solid organ recipients: a retrospective study

Background

SARS-CoV-2, a novel corona virus, has caused clusters of fatal pneumonia worldwide. Immune compromised patients are among the high risk groups with poor prognosis of the disease. The presence of bacterial or fungal co-infections with SARS-CoV-2 is associated with increased mortality.

Methods

The electronic data of the liver and kidney recipients, hospitalized in COVID-19 intensive care unit in an 8-month period in 2020 were retrospectively assessed. The documented bacterial or fungal infections alongside with outcome and risk factors were recorded and analyzed by binary logistic regression model and multivariate analyses.

Results

Sixty-Six liver and kidney recipients with positive RT-PCR for SARS-CoV-2 were included this study. Twenty one percent of the patients had at least one episode of co-infection during their COVID-19 course. Bacterial and fungal co-infections contributed to a significantly higher mortality. Urine and sputum were the most common sites of pathogen isolation (45.45% and 36.36%; respectively). The majority of infections were caused by vancomycin- resistant Enterococci (30%). Escherichia coli stood in the next position with 23.3%. Prior hospitalization and high doses of corticosteroids were associated with co-infections (p < 0.001 and p = 0.02; respectively.)

Conclusions

Bacterial and fungal co-infections with COVID-19 are more prevalent in solid organ recipients compared to the general population. Prior hospitalizations and use of broad-spectrum antimicrobial agents lead to emergence of multi-drug resistant pathogens in this susceptible patient population. Early detection and treatment of co-infections as well as antibiotic stewardship is recommended in solid organ recipients.

How to adapt an intestinal microbiota transplantation programme to reduce the risk of invasive multidrug-resistant infection

BACKGROUND

Vulnerable patients with intestinal colonization of multidrug-resistant organisms (MDROs) are recognized to be at increased risk of invasive MDRO-driven infection. Intestinal microbiota transplantation (IMT, also called faecal microbiota transplant) is the transfer of healthy screened donor stool to an affected recipient, and recent interest has focused on its impact on the reduction of invasive MDRO infection.

OBJECTIVES

To describe how to establish a clinical IMT pathway for patients at risk of MDRO invasive infection, with special considerations for optimizing administration and assessment of endpoints.

SOURCES

Expert guidelines and peer-reviewed clinical studies are encompassed and discussed.

CONTENT

IMT is offered to patients with MDROs detected on rectal or stool screening and either at risk of MDRO invasive infection due to altered immune status or those with recurrent MDRO-mediated invasive disease and considered at risk of further disease. Donor screening should include pathogens with theoretical or demonstrated risk of transmission (including MDROs themselves and SARS-CoV-2) and take into consideration the relative immunosuppressed state of potential recipients. Delivery of IMT is timed for when the patient is free from active infection, but no additional antibiotics are indicated. If administered when future immunosuppression is to take place, IMT is aligned at least 2 weeks beforehand to ensure sufficient time for engraftment. Patients are followed up in terms of adverse effects from IMT and clinicians are advised to discuss with the IMT multidisciplinary team on choice of antibiotics if needed to take into consideration the impact upon the intestinal microbiome. Prevention of invasive disease is the primary measure of success, rather than using intestinal decolonization as a binary outcome. Repeat IMT is considered case by case.

IMPLICATIONS

Future research areas should include randomized studies that consider clinical outcomes and cost-effectiveness, and better understanding of mechanisms to identify markers of treatment success and functional microbiome components that could be used therapeutically.

Diagnostic Value of Procalcitonin in Transplant Patients Receiving Immunosuppressant Drugs: A Retrospective Electronic Medical Record-Based Analysis

OBJECTIVES

To evaluate concentrations of procalcitonin (PCT) in transplant recipients receiving immunosuppressive therapy compared with nonimmunosuppressed patients.

METHODS

We analyzed a data set of 9,500 inpatient encounters to compare levels of PCT and other biomarkers of infection (C-reactive protein [CRP], WBC count, and absolute neutrophil count [ANC]) between immunosuppressed and nonimmunosuppressed cohorts. We also assessed the correlation between PCT and clinical variables in immunosuppressed patients.

RESULTS

Patients receiving immunosuppressive drugs had significantly higher levels of maximal and minimal PCT compared with the nonimmunosuppressed patients (P < .0001 and P = .0019, respectively). However, CRP levels, WBC count, and ANC were significantly lower in immunosuppressed patients compared with the nonimmunosuppressed patients (P = .0003, P < .0019, and P = .0001, respectively).

CONCLUSIONS

Our results from real-world data demonstrated that PCT dynamics remain intact despite immunosuppressive therapy, in contrast to other biomarkers such as CRP, WBC, and ANC. In addition, higher PCT levels are associated with systemic infections and reflect disease severity.

Alteration of the gut microbiome in mycophenolate-induced enteropathy: impacts on the profile of short-chain fatty acids in a mouse model

BACKGROUND

Mycophenolic acid (MPA) is the most widely used immunosuppressive drug in transplantation and for autoimmune diseases. Unfortunately, more than 30% of patients experience a typical gastrointestinal adverse effect also referred to as mycophenolate-induced enteropathy. Due to its antibacterial, antifungal, and antiviral properties, MPA exposure is associated with intestinal dysbiosis characterized by a decrease in density and diversity of the microbiome regarding the main bacterial phyla (Firmicutes and Bacteroidetes). These bacterial phyla are known for their metabolic role in maintaining the homeostasis of the digestive tract, particularly through the production of short-chain fatty acids (SCFA) that could contribute to the pathophysiology of mycophenolate-induced enteropathy. Our study aimed at deciphering short-chain fatty acids (SCFA) profile alterations associated with gastrointestinal toxicity of MPA at the digestive and systemic levels in a mouse model.

METHODS

Ten-week old C57BL/6 (SOPF) mice were randomly assigned in 2 groups of 9 subjects: control, and mycophenolate mofetil (MMF, 900 mg/kg/day). All mice were daily treated by oral gavage for 7 days. Individual faecal pellets were collected at days 0, 4 and 8 as well as plasma at day 8 for SCFA profiling. Additionally, after the sacrifice on day 8, the caecum was weighted, and colon length was measured. The proximal colon was cut for histological analysis.

RESULTS

MMF treatment induced around 10% weight loss at the end of the protocol associated with a significant decrease in caecum weight and a slight reduction in colon length. Histological analysis showed significant architectural changes in colon epithelium. Moreover, we observed an overall decrease in SCFA concentrations in faecal samples, especially regarding acetate (at day 8, control 1040.6 ± 278.161 μM versus MMF 384.7 ± 80.5 μM, p < 0.01) and propionate (at day 8, control 185.94 ± 51.96 μM versus MMF 44.07 ± 14.66 μM, p < 0.001), and in plasma samples for butyrate (at day 8, control 0.91 ± 0.1 μM versus MMF 0.46 ± 0.1 μM, p < 0.01).

CONCLUSIONS

These results are consistent with functional impairment of the gut microbiome linked with digestive or systemic defects during MMF treatment.

Clinical impact of vancomycin-resistant enterococci colonization in nonliver solid organ transplantation and its implications for infection control strategies: A single-center, 10-year retrospective study

BACKGROUND

Vancomycin-resistant enterococci (VRE) colonization in nonliver solid organ transplantation (SOT) is poorly defined. Infection control management of these patients is influenced by the association of VRE with adverse outcomes in liver transplantation. This study examines the frequency and clinical impact of VRE colonization specifically on nonliver SOT patients and discusses implications for nosocomial VRE control.

METHODS

We retrospectively reviewed all nonliver SOT patients at a single transplant center from 2005 to 2015. We determined colonization rates in the peritransplant period and the rate of VRE infections. The association between VRE colonization with 90-day mortality and other clinical outcomes was examined.

RESULTS

There were 1786 nonliver SOTs from 2005 to 2015, with 81 (4.6%) colonized with VRE in the peritransplantation period. The colonization prevalence varied by organ type: 45 of 423 lung (10.6%), 12 of 352 heart (3.4%), one of 18 heart-lung (5.6%), 20 of 884 kidney (2.3%), three of 63 kidney-pancreas (4.8%), zero of 11 pancreas, zero of five small bowel, and zero of 11 multivisceral. Peritransplant VRE colonization was not associated with 90-day mortality odds ratio = 2.35 (95% CI = 0.53, 10.29) and adjusted odds ratio = 1.52 (95% CI = 0.34, 6.88). In the multivariable logistic regression, there was no association with mortality at 1 year or 5 years, hospital length of stay, rehospitalization, or days alive out of hospital. There were 14 inpatient VRE infections up to 1 year after transplantation.

CONCLUSION

Nonliver SOT patients have lower rates of VRE colonization than liver SOT, and colonization was not associated with increased adverse clinical outcomes. Although infection control strategies for VRE in hospital remain controversial, nonliver SOT should be considered among typical hospitalized patients when designing strategies for prevention.

Short versus prolonged antibiotic treatment for complicated urinary tract infection after kidney transplantation

There is no consensus regarding the optimal duration of antibiotic therapy for urinary tract infection (UTI) following kidney transplantation (KT). We performed a retrospective study comparing short (6-10 days) versus prolonged (11-21 days) antibiotic therapy for complicated UTI among KT recipients. Univariate and inverse probability treatment weighted (IPTW) adjusted multivariate analysis for composite primary outcome of all-cause mortality or readmissions within 30 days and relapsed UTI 180 days were performed. Overall, 214 KT recipients with complicated UTI were included; 115 short-course treatment (median 8, interquartile range [IQR] 6-9 days), 99 prolonged course (median 14, IQR 12-21 days). The composite outcome occurred in 33 (28.6%) in the short-course group and 30 (30%) in the prolonged-course group; relapsed UTI occurred in 19 (16.5%) vs. 21 (21%), respectively. Duration of antibiotic treatment was not associated with any of these outcomes. The only risk factor for mortality/readmissions in multivariate analysis was deceased donor. No differences between groups were demonstrated for length of hospital stay, rates of bacteraemia, resistance development, and serum creatinine at 30 and 90 days. In conclusion, we found no difference in clinical outcomes between KT recipients treated for complicated UTI with short-course antibiotic (6-10 days) versus longer course (11-21 days).

Chest Infections after Lung Transplantation

Despite substantial progress in the long-term follow-up strategies for lung transplant recipients, morbidity and mortality remain high mostly due to the elevated infectious risk and to the development of chronic lung allograft dysfunction. The high immunosuppressive levels necessary to prevent acute rejection and the graft's constant exposure to the environment come at the high price of frequent infectious complications. Moreover, some infectious agents have been shown to trigger acute rejection or chronic allograft dysfunction. A rapid diagnostic approach followed by an early treatment and follow-up strategy are of paramount importance. They are, however, challenging endeavors due to the vast spectrum of possible pathogens and to the discrete clinical features as a consequence of transplant recipients' impaired immune response. This review proposes a stratified diagnostic strategy, discusses the most relevant pathogens and the corresponding therapeutic approaches while also offering an insight in the infection prevention strategies: vaccination, prophylaxis, preemptive therapy, antibiotic stewardship.

Outbreaks in Health Care Settings

Outbreaks and pseudo-outbreaks in health care settings are complex and should be evaluated systematically using epidemiologic and molecular tools. Outbreaks result from failures of infection prevention practices, inadequate staffing, and undertrained or overcommitted health care personnel. Contaminated hands, equipment, supplies, water, ventilation systems, and environment may also contribute. Neonatal intensive care, endoscopy, oncology, and transplant units are areas at particular risk. Procedures, such as bronchoscopy and endoscopy, are sources of infection when cleaning and disinfection processes are inadequate. New types of equipment can be introduced and lead to contamination or equipment and medications can be contaminated at the manufacturing source.

New drugs for difficult bugs: management of multidrug-resistant gram-negative infections in solid organ transplant recipients

PURPOSE OF REVIEW

Multidrug-resistant Gram-negative bacteria remain a significant threat to patient and allograft survival. Management of these infections in solid organ transplant (SOT) recipients remains challenging due to a limited antimicrobial pipeline and reliance on novel agents, which have not been systematically evaluated in the transplant population.

RECENT FINDINGS

Novel antimicrobials, including the second-generation β-lactam/β-lactamase inhibitors, cefiderocol, plazomicin and eravacycline, have been developed to combat infections due to multidrug-resistant Gram-negative infections, but each has microbiologic and therapeutic niches and warrant further study in SOT recipients.

SUMMARY

This review summarizes therapeutic options for extended-spectrum β-lactamase-producing Enterobacterales, carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa with difficult-to-treat resistance in SOT recipients and emphasizes recently approved antimicrobial agents.

In vitroassessment of green polyhydroxybutyrate/chitosan blend loaded with kaempferol nanocrystals as a potential dressing for infected wounds

Despite the major medical advancements in recent decades, treating infected wounds successfully remains a challenge. In this research, a functional blend of Polyhydroxybutyrate (PHB) and Chitosan (Cs) was developed for wound infection mitigation with tailored biological and physicochemical properties. Water insoluble kaempferol (KPF) was pre-formulated to water soluble KPF nanocrystals (KPF-NCs) with fine particle size of 145 ± 11 nm, and high colloidal stability (-31 ± 0.4 mV) to improve its drug transdermal delivery. PHB-Cs-KPF-NCs (1:2 ratio) film owned the best physical properties in terms of high breathability, thermal stability and mechanical strength (33 ± 1 MPa). Besides, XRD and FTIR findings indicated the interaction between Cs, PHB and KPF, reducing the film crystallinity. The scanning electron microscopy of the film displayed a highly interconnected porous morphology. KPF-NCs were integrated in PHB-Cs matrix with a marked encapsulation efficiency of 96.6%. The enhanced drug-loading film showed a sustain release pattern of KPF-NCs over 48 h. Interestingly, the developed blend possessed an impressive blood clotting capacity within 20 min. Furthermore, we presented a new naturally-sourced mixture of Cs+KPF-NCs with powerful antibacterial effects against MDRStaphylococcus aureusandAcentibacter baumanniiat very low concentrations. The membrane evidenced a remarkable antibacterial naturein vitrowith almost 100% cell viability reduction against the study strains after 48 h. By virtue of these advantages, this green blend is highly proposed for optimal wound care.

Asymptomatic Bacteriuria in Post Renal Transplant Patients: To Treat or Not?

Urinary tract infections (UTIs) can commonly occur within the first few weeks following kidney transplantation procedures. Although the management of asymptomatic bacteriuria and acute graft pyelonephritis is important to reduce the risk of graft rejections following kidney transplantation, the efficacy of antibiotics administration remains controversial among studies in the literature. The aim of this review is to elaborate more on asymptomatic bacteriuria following kidney transplantation and try to formulate proper evidence about the efficacy of antibiotics administration on eliminating the frequency of infections and enhancing the quality of care for patients. Most studies in the literature are observational, which are usually biased in the interventions. However, the current evidence regarding the management and screening of asymptomatic bacteriuria seems to discourage such an approach. Almost all of the included studies reported that antibiotic administration did not significantly lower the rates of secondary symptomatic UTIs or enhance the functions of the graft. In addition, there is no significant impact on mortality and other clinical outcomes. Lastly, the frequent administration of antibiotics can significantly increase the risk of recurrence due to the emergence of novel strains of bacteria that are resistant to the currently administered antibiotics making it unfavorable.

Risk Factors and Outcome of Multidrug-Resistant Infections after Heart Transplant: A Contemporary Single Center Experience

(1) Background: The aim of this study was to assess risk factors for multidrug-resistant/extensively drug-resistant (MDR/XDR) bacterial infections in heart transplant (HT) patients within three months after surgery and its impact on patient outcome. (2) Methods: Retrospective analysis of clinical, hemato-chemical, imaging, treatment and outcome data from 47 heart transplant recipients from January 2016 to December 2018. MDR/XDR infections were compared to non-MDR/XDR and noninfected patients. (3) Results: Most participants were males, median age 51 years: 35 (74.5%) developed an infection after HT; 14 (29.8%) were MDR/XDR infections. Prolonged hospital stay before HT correlated to MDR/XDR infection (p < 0.001). Sequential organ failure assessment (SOFA) score at sampling day was higher in MDR/XDR (p = 0.027). MDR/XDR were mostly blood-stream (BSI) (p = 0.043) and skin-soft tissue (SSTI) (p = 0.047) infections. Gram-negative infections were the most frequent, specifically carbapenem-resistant Klebsiella pneumoniae. Antibiotic therapy duration for MDR/XDR infections was longer (p = 0.057), eradication rate lower (p = 0.083) and hospital stay longer (p = 0.005) but not associated with a worse outcome. (4) Conclusions: MDR/XDR infections affect compromised HT recipients with a history of prolonged hospitalization, causing a lower rate of eradication and increased hospital stay. These frequently present as BSI and SSTI. We emphasize the need to prevent contamination of central venous catheters and the surgical site.

Incidence and risk factors for respiratory tract bacterial colonization and infection in lung transplant recipients

To evaluate incidence of and risk factors for respiratory bacterial colonization and infections within 30 days from lung transplantation (LT). We retrospectively analyzed microbiological and clinical data from 94 patients transplanted for indications other than cystic fibrosis, focusing on the occurrence of bacterial respiratory colonization or infection during 1 month of follow-up after LT. Thirty-three percent of patients developed lower respiratory bacterial colonization. Bilateral LT and chronic heart diseases were independently associated to a higher risk of overall bacterial colonization. Peptic diseases conferred a higher risk of multi-drug resistant (MDR) colonization, while longer duration of aerosol prophylaxis was associated with a lower risk. Overall, 35% of lung recipients developed bacterial pneumonia. COPD (when compared to idiopathic pulmonary fibrosis, IPF) and higher BMI were associated to a lower risk of bacterial infection. A higher risk of MDR infection was observed in IPF and in patients with pre-transplant colonization and infections. The risk of post-LT respiratory infections could be stratified by considering several factors (indication for LT, type of LT, presence of certain comorbidities, and microbiologic assessment before LT). A wider use of early nebulized therapies could be useful to prevent MDR colonization, thus potentially lowering infectious risk.

Infective endocarditis in patients with solid organ transplantation. A nationwide descriptive study

BACKGROUND

Solid organ transplantation (SOT) implies immunosuppression and frequent health care contact. Our aim was to compare the characteristics of patients with infective endocarditis (IE) and SOT against those without SOT.

METHODS

We used data from the Spanish Collaboration on Endocarditis during the period 2008-2018.

RESULTS

We identified 4794 cases of IE, 85 (1.8%) in SOT (56 kidney, 18 liver, 8 heart, 3 lung). Thirteen patients with other transplantation types (bone marrow, hematopoietic precursors, and cornea) were excluded from the analysis. Compared with patients without SOT, patients with SOT had lower median age (61 vs. 69 years, p<0.001), more comorbidities (mean age-adjusted Charlson index 5.7±2.9 vs. 4.9±2.9, p=0.004), a lower prevalence of native valvular heart disease (29.4 vs. 45.4%, p=0.003), more in-hospital and healthcare-related IE (70.5% vs. 36.3%, p<0.001) and staphylococcal etiology (57.7% vs. 39.7%, p=0.001). Patients with SOT had more frequent kidney function worsening (47.1% vs. 34.6%, p=0.02), septic shock (25.9% vs. 12.1 %, p<0.001), sepsis (27.1% vs. 17.2%, p=0.02), and less surgery indication (54.1% vs 66.3%, p=0.02) and surgery (32.9% vs. 46.3%, p=0.01) than patients without SOT. There were no significant differences in mortality: inhospital (30.6% SOT vs. 25.6% without SOT, p=0.31), 1-year (38.8% SOT vs. 31.9% without SOT, p=0.18).

CONCLUSIONS

Most IE in SOT recipients are nosocomial and over 70% are health care-related. Half have previously normal heart valves and almost 60% are due to Staphylococcus spp. infections. Mortality seems to be similar to non-SOT counterparts.

Efficacy and safety of oral fosfomycin for asymptomatic bacteriuria in kidney transplant recipients: Results from a Spanish multicenter cohort

Current guidelines recommend against systematic screening or treating asymptomatic bacteriuria (AB) among kidney transplant (KT) recipients, although the evidence regarding episodes occurring early after transplantation or in the presence of anatomical abnormalities is inconclusive. Oral fosfomycin may constitute a good option for the treatment of post-transplant AB, particularly due to the emergence of multidrug-resistant (MDR) uropathogens. Available clinical evidence supporting its use in this specific setting, however, remains scarce. We performed a retrospective study in 14 Spanish institutions from January 2005 to December 2017. Overall, 137 episodes of AB diagnosed in 133 KT recipients treated with oral fosfomycin (calcium and trometamol salts) with a test-of-cure urine culture within the first 30 days were included. Median time from transplantation to diagnosis was 3.1 months (interquartile range [IQR]: 1.1 - 10.5). Most episodes (96.4% [132/137]) were caused by gram-negative bacteria (GNB), and 56.9% (78/137) were categorized as MDR (extended-spectrum β-lactamase-producing Enterobacterales [20.4%] and carbapenem-resistant GNB [2.9%]). Rate of microbiological failure at month 1 was 40.1% (95% confidence interval [95%CI]: 31.9 - 48.9) for the whole cohort and 42.3% (95%CI: 31.2 - 54.0) for episodes due to MDR pathogens. Previous urinary tract infection (odds ratio [OR]: 2.42; 95%CI: 1.11 - 5.29; P-value = 0.027) and use of fosfomycin as salvage therapy (OR: 8.31; 95%CI: 1.67 - 41.35; P-value = 0.010) were predictors of microbiological failure. No severe treatment-related adverse event were detected. Oral fosfomycin appears to be a suitable and safe alternative for the treatment (if indicated) of AB after KT, including those episodes due to MDR uropathogens.

Clinical Outcome of Vancomycin-Resistant Enterococcus Colonization Among Liver Transplant Recipients at Shiraz Organ Transplant Center

OBJECTIVES

Liver transplant recipients are more susceptible to vancomycin-resistant enterococci colonization than healthy individuals. We investigated the prevalence of vancomycin-resistant enterococci colonization and its effect on the outcomes of liver transplant recipients.

MATERIALS AND METHODS

Patients who had undergone primary liver transplant at the Shiraz Organ Transplant Center from 2015 to 2017 were enrolled in this study. Demographic characteristics, laboratory test results, duration of stay in the intensive care unit, total duration of hospital stay, and clinical outcome data were extracted from the Shiraz Organ Transplant Center database. Posttransplant outcomes such as graft rejection, mortality, hospital stay, and kidney function tests were included for the first 90 days after transplant.

RESULTS

A total of 753 liver transplant recipients (470 males and 283 females) were included in this study. Vancomycin-resistant enterococci colonization was identified in 51 patients (6.8%) after transplant at the time of intensive care unit admission. Our study found no significant difference between outcomes for patients with vancomycin-resistant enterococci colonization and outcomes for patients without colonization, including graft rejection, mortality, hospital stay, and kidney function tests.

CONCLUSIONS

Our study revealed that asymptomatic vancomycin-resistant enterococci colonization in liver transplant patients has no adverse effect on the duration of posttransplant hospital stay, early mortality rate, graft rejection rate, or kidney function compared with noncolonized patients.

Gut microbiota profiling in hematopoietic stem cell transplant recipients: Towards personalized medicine

BACKGROUND

Antibiotic resistance in bacteria is a cause for concern, especially in hematopoietic stem cell transplant (HSCT) patients. Endogenous bowel microflora in HSCT patients get replaced by hospital multidrug resistant flora and pose risk of serious bacterial infection during the pre-engraftment stage. For decades, many methods to reduce the translocation of gut microbiota in HSCT patients have been attempted. Despite the logic, of using prophylactic antibiotics, there is no consensus on standard regimen. Personalized antibiotic prophylaxis-based on gut microbiota and clinical profile has been suggested by researchers. In this study, gut microbiota in HSCT recipients has been studied with antimicrobial susceptibility testing and detection of various antibiotic resistance phenotypes.

METHODS

Seventy-six HSCT patients (2016-2018) were included. Stool surveillance cultures and antibiotic susceptibility testing were performed. Bacterial isolates were classified into various antibiotic resistance phenotypes.

RESULTS

This study revealed that 73.75% HSCT recipients had gut colonized with antibiotic resistance microbiota which included extended-spectrum β-lactamase-, multidrug- and extensively drug-resistant phenotypes.

CONCLUSION

This study reiterates the importance of individual profiling of gut microbiota in HSCT patients.

Oral decontamination with colistin plus neomycin in solid organ transplant recipients colonized by multidrug-resistant Enterobacterales: a multicentre, randomized, controlled, open-label, parallel-group clinical trial

OBJECTIVES

To evaluate the efficacy of oral colistin-neomycin in preventing multidrug-resistant Enterobacterales (MDR-E) infections in solid organ transplant (SOT) recipients.

METHODS

Multicentre, open-label, parallel-group, controlled trial with balanced (1:1) randomization in five transplant units. SOT recipients were screened for MDR-E intestinal colonization (extended-spectrum β-lactamase or carbapenemase producing) before transplantation and +7 and + 14 days after transplantation and assigned 1:1 to receive treatment with colistin sulfate plus neomycin sulfate for 14 days (decolonization treatment (DT) group) or no treatment (no decolonization treatment (NDT) group). The primary outcome was diagnosis of an MDR-E infection. Safety outcomes were appearance of adverse effects, mainly diarrhoea, rash, nausea and vomiting. Patients were monitored weekly until 30 days after treatment. Intention-to-treat analysis was performed.

RESULTS

MDR-E rectal colonization was assessed in 768 SOT recipients; 105 colonized patients were included in the clinical trial, 53 receiving DT and 52 NDT. No significant decrease in the risk of infection by MDR-E was observed in the DT group (9.4%, 5/53) compared to the NDT group (13.5%, 7/52) (relative risk 0.70; 95% confidence interval 0.24-2.08; p 0.517). Four patients (5.6%), three (5.6%) in the DT group and one (1.9%) in the NDT group, developed colistin resistance. Twelve patients (22.7%) in the DT group had diarrhoea, eight related to treatment (15.0%); one patient (1.8%) developed skin rash and another (1.8%) nausea and vomiting. Two patients (3.8%) in the NDT group developed diarrhoea.

CONCLUSIONS

DT does not reduce MDR-E infections in SOT. Colistin resistance and adverse effects such as diarrhoea are a potential issue that must be taken seriously.