Prevalence of multidrug-resistant gram-negative bacilli producing extended-spectrum β-lactamases (ESBLs) and ESBL genes in solid organ transplant recipients

Challenges of Antimicrobial Resistance and Stewardship in Solid Organ Transplant Patients

Purpose of Review

Without effective antimicrobials, patients cannot undergo transplant surgery safely or sustain immunosuppressive therapy. This review examines the burden of antimicrobial resistance in solid organ transplant recipients and identifies opportunities for antimicrobial stewardship.

Recent Findings

Antimicrobial resistance has been identified to be the leading cause of death globally. Multidrug-resistant pathogens are associated with significant morbidity and mortality in transplant recipients. Methicillin-resistant S. aureus affects liver and lung recipients, causing bacteremia, pneumonia, and surgical site infections. Vancomycin-resistant enterococci is a nosocomial pathogen primarily causing bacteremia in liver recipients. Multidrug-resistant Gram-negative pathogens present urgent and serious threats to transplant recipients. Extended-spectrum beta-lactamase-producing E. coli and K. pneumoniae commonly cause bacteremia and intra-abdominal infections in liver and kidney recipients. Carbapenemase-producing Enterobacterales, mainly K. pneumoniae, are responsible for infections early-post transplant in liver, lung, kidney, and heart recipients. P. aeruginosa and A. baumannii continue to be critical threats. While there are new antimicrobial agents targeting resistant pathogens, judicious prescribing is crucial to minimize emerging resistance. The full implications of the COVID-19 global pandemic on antimicrobial resistance in transplant recipients remain to be understood. Currently, there are no established standards on the implementation of antimicrobial stewardship interventions, but strategies that leverage existing antimicrobial stewardship program structure while tailoring to the needs of transplant recipients may help to optimize antimicrobial use.

Summary

Clinicians caring for transplant recipients face unique challenges tackling emerging antimcirobial resistance. Coordinated antimicrobial stewardship interventions in collaboration with appropriate expertise in transplant and infectious diseases may mitigate against such threats.

Multidrug-resistant organisms: A significant cause of severe sepsis in pediatric intestinal and multi-visceral transplantation

Severe sepsis in immunocompromised children is associated with increased mortality. This paper describes the epidemiology landscape, clinical acuity, and outcomes for severe sepsis in pediatric intestinal (ITx) and multi-visceral (MVTx) transplant recipients requiring admission to the pediatric intensive care unit (PICU). Severe sepsis episodes were retrospectively reviewed in 51 ITx and MVTx patients receiving organs between 2009 and 2015. Twenty-nine (56.8%) patients had at least one sepsis episode (total of 63 episodes) through December 2016. Bacterial etiologies accounted for 66.7% of all episodes (n = 42), occurring a median of 122.5 days following transplant (IQR 59-211.8 days). Multidrug-resistant organisms (MDROs) accounted for 73.8% of bacterial infections; extended spectrum beta-lactamase producers, vancomycin-resistant enterococcus, and highly-resistant Pseudomonas aeruginosa were the most commonly identified. Increased mechanical ventilation and vasoactive requirements were noted in MDRO episodes (OR 3.03, 95% CI 1.09-8.46 and OR 3.07, 95% CI 1.09-8.61, respectively; p < .05) compared to non-MDRO episodes. PICU length of stay was significantly increased for MDRO episodes (7 vs. 3 days, p = .02). Graft loss was 24.1% (n = 7) and mortality was 24.1% (n = 7) in patients who experienced severe sepsis. Further attention is needed for MDRO risk mitigation and modification of sepsis treatment guidelines to ensure MDRO coverage for this population.

Antibiotic-Resistant Infections and Treatment Challenges in the Immunocompromised Host: An Update

This article reviews antibiotic resistance and treatment of bacterial infections in the growing number of patients who are immunocompromised: solid organ transplant recipients, the neutropenic host, and persons with human immunodeficiency virus and AIDS. Specific mechanisms of resistance in both gram-negative and gram-positive bacteria, as well as newer treatment options are addressed elsewhere and are only briefly discussed in the context of the immunocompromised host.

High prevalence of multidrug-resistant gram-negative bacterial infection following pediatric liver transplantation

Bacterial infection has been identified as one of the most significant complications of liver transplantation (LT). Multidrug-resistant (MDR) gram-negative bacteria (GNB) infection remains problematic issue following LT in the adults. However, data in children are scarce. We aimed to examine the prevalence and associated factors of MDR-GNB infection among pediatric LT recipients.We performed a single-center retrospectively study of 118 children who underwent LT between January 2010 and December 2018. Data on the prevalence, clinical characteristics, types, and sites of MDR-GNB infection within 3 months after LT as well as the treatment outcomes were collected. Multidrug resistance was defined as acquired non-susceptibility to at least 1 agent in 3 or more antibiotic classes.In total, 64 (53.7%) patients developed 96 episodes of culture-proven bacterial infection with 93 GNB isolates. Moreover, there were 58 (62.4%) MDR-GNB isolates, with a predominance of Klebsiella pneumoniae (32.7%), Escherichia coli (31%), and Pseudomonas aeruginosa (10.3%). Interestingly, 10 (17.2%) isolates were determined to be carbapenem-resistant Enterobacteriaceae. The median time to MDR-GNB infection was 9 (interquartile range: 5-33) days. The most common type of infection was intra-abdominal infection (47.9%). In the multivariate analysis, the significant variables associated with post-LT MDR-GNB infection include exposure to third-generation cephalosporins (hazard ratio [HR]: 2.16, P = .023), operative time (hazard ratio [HR] 1.20, P = .009), and length of intensive care unit stay (HR 1.03, P = .049). With a focus on carbapenem-resistant Enterobacteriaceae infection, a pediatric end-stage liver disease score >21 was the only significant 6 variable in the multivariate analysis (HR 11.48, P = .024). The overall 3-month mortality rate was 6.8%.This study has highlighted the high prevalence rate of MDR-GNB infection after pediatric LT. Therefore, caution on the emergence of MDR-GNB infection should be paid in at-risk children. Moreover, knowledge regarding the prevalence of MDR-GNB infection and resistant patterns is essential for guideline development to prevent and minimize the risk of MDR-GNB infection in this group of patients.

Early Bacterial Infections After Pediatric Liver Transplantation in the Era of Multidrug-resistant Bacteria: Nine-year Single-center Retrospective Experience

BACKGROUND

Early bacterial infection is a major and severe complication after liver transplantation (LT). The rise of antimicrobial resistance, especially extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE), is a growing concern for these patients. This study aimed to assess the epidemiology of early bacterial infections in a pediatric population, including those caused by multidrug-resistant (MDR) pathogens, and to identify risk factors for infection.

METHODS

We conducted a monocentric retrospective study including 142 consecutive LTs performed in 137 children between 2009 and 2017.

RESULTS

Ninety-three bacterial infections occurred after 67 (47%) LTs. Among the 82 isolated pathogens, the most common was Klebsiella pneumoniae (n = 19, 23%). Independent risk factors for early bacterial infection were low weight [odds ratio (OR) = 0.96; 95% confidence interval (CI): 0.9-0.99; P = 0.03] and the presence of a prosthetic mesh (OR = 2.4; 95% CI: 1.1-5.4; P = 0.046). Sixty-one children (45%) carried MDR bacteria and 16 infections were caused by MDR pathogens, especially ESBL-producing K. pneumoniae (n = 12). ESBL-PE stool carriage was associated with ESBL-PE infection (OR = 4.5; 95% CI: 1.4-17.4; P = 0.02). Four children died from an infection, three due to ESBL-producing K. pneumoniae.

CONCLUSIONS

This study confirmed a shift toward a predominance of Gram-negative early bacterial infections after pediatric LT. The risk factors for infection were low weight and the presence of a prosthetic mesh. ESBL-PE stool carriage was associated with ESBL-PE infection. Adapted antimicrobial prophylaxis and personalized antibiotherapy are mandatory to reduce infection prevalence and mortality.

Minocycline, focus on mechanisms of resistance, antibacterial activity, and clinical effectiveness: Back to the future

OBJECTIVES

The increasing crisis regarding multidrug-resistant (MDR) and extensively drug-resistant microorganisms leads to appealing therapeutic options.

METHODS

During the last 30 years, minocycline, a wide-spectrum antimicrobial agent, has been effective against MDR Gram-positive and Gram-negative bacterial infections. As with other tetracyclines, the mechanism of action of minocycline involves attaching to the bacterial 30S ribosomal subunit and preventing protein synthesis.

RESULTS

This antimicrobial agent has been approved for the treatment of acne vulgaris, some sexually transmitted diseases and rheumatoid arthritis. Although many reports have been published, there remains limited information regarding the prevalence, mechanism of resistance and clinical effectiveness of minocycline.

CONCLUSION

Thus, we summarize here the currently available data concerning pharmacokinetics and pharmacodynamics, mechanism of action and resistance, antibacterial activity and clinical effectiveness of minocycline.

Multidrug-resistant Gram-negative bacterial infections in solid organ transplant recipients-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of infections due to multidrug-resistant (MDR) Gram-negative bacilli in the pre- and post-transplant period. MDR Gram-negative bacilli, including carbapenem-resistant Enterobacteriaceae, MDR Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii, remain a threat to successful organ transplantation. Clinicians now have access to at least five novel agents with activity against some of these organisms, with others in the advanced stages of clinical development. No agent, however, provides universal and predictable activity against any of these pathogens, and very little is available to treat infections with MDR nonfermenting Gram-negative bacilli including A baumannii. Despite advances, empiric antibiotics should be tailored to local microbiology and targeted regimens should be tailored to susceptibilities. Source control remains an important part of the therapeutic armamentarium. Morbidity and mortality associated with infections due to MDR Gram-negative organisms remain unacceptably high. Heightened infection control and antimicrobial stewardship initiatives are needed to prevent these infections, curtail their transmission, and limit the evolution of MDR Gram-negative pathogens, especially in the setting of organ transplantation.

Infections in live donor liver transplant recipients: A study of timeline, aetiology and antimicrobial resistance of bacterial and fungal infections from the developing world

Infections are the leading cause of morbidity and mortality in liver transplant (LT) recipients. We studied timeline, spectrum of infection, system involved, and antimicrobial resistance in 64 patients undergoing live donor LT with 6-month follow-up. Of 64 patients, 38 (59.5%) patients had 103 infectious episodes, 10 patients had single infectious episode and 28 patients had two or more infectious episodes. 96 (93.2%) were bacterial and Candida infections were in 7 (6.8%). Early phase had 30 (29.1%) episodes; intermediate phase 25 (24.2%) and late phase 48 (46.6%). Mortality was 11/64 (17.1%). Knowledge of timeline, aetiological agent and antimicrobial resistance is useful to guide empirical therapy and infection prevention.

Antibiotic-Resistant Infections and Treatment Challenges in the Immunocompromised Host

This article reviews antibiotic resistance and treatment of bacterial infections in the growing number of patients who are immunocompromised: solid organ transplant recipients, the neutropenic host, and persons with human immunodeficiency virus and AIDS. Specific mechanisms of resistance in both gram-negative and gram-positive bacteria, as well as newer treatment options are addressed elsewhere, and are only briefly discussed in the context of the immunocompromised host.

Infections in pediatric solid-organ transplant recipients

Solid-organ transplantation in pediatrics can be a life-saving procedure, but it cannot be accomplished without risk of infection-related morbidity and mortality. Evaluation of the recipient during candidacy and donor during evaluation can assist with identification of risk. Further, risk of infection from the surgical procedure can be mitigated through careful planning and attention to infection prevention processes. Finally, early recognition of infection posttransplant can limit the impact of these events.

Management of multidrug resistant Gram-negative bacilli infections in solid organ transplant recipients: SET/GESITRA-SEIMC/REIPI recommendations

Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant (MDR) Gram-negative bacilli (GNB), as they are frequently exposed to antibiotics and the healthcare setting, and are regulary subject to invasive procedures. Nevertheless, no recommendations concerning prevention and treatment are available. A panel of experts revised the available evidence; this document summarizes their recommendations: (1) it is important to characterize the isolate's phenotypic and genotypic resistance profile; (2) overall, donor colonization should not constitute a contraindication to transplantation, although active infected kidney and lung grafts should be avoided; (3) recipient colonization is associated with an increased risk of infection, but is not a contraindication to transplantation; (4) different surgical prophylaxis regimens are not recommended for patients colonized with carbapenem-resistant GNB; (5) timely detection of carriers, contact isolation precautions, hand hygiene compliance and antibiotic control policies are important preventive measures; (6) there is not sufficient data to recommend intestinal decolonization; (7) colonized lung transplant recipients could benefit from prophylactic inhaled antibiotics, specially for Pseudomonas aeruginosa; (8) colonized SOT recipients should receive an empirical treatment which includes active antibiotics, and directed therapy should be adjusted according to susceptibility study results and the severity of the infection.

Factors influencing mortality in abdominal solid organ transplant recipients with multidrug-resistant gram-negative bacteremia

Background

Although multidrug-resistant (MDR) gram-negative bacteremia (GNB) has been recognized as an important cause of morbidity and mortality among abdominal solid organ transplant (ASOT) recipients, there are no data on its prognostic factors after an interim standard definition of MDR was proposed in 2012. The objective of this study was to describe the epidemiology, microbiology, and predictors of infection-related 30-day mortality in ASOT recipients with MDR GNB.

Methods

We performed a retrospective, double-center analysis of ASOT patients with MDR GNB over a 13-year study period. Univariate and multivariate analyses were performed to identify the risk factors for mortality.

Results

During the observational period, 2169 subjects underwent ASOT. Ninety-nine episodes of MDR GNB were diagnosed in 91 (4.6%) ASOT recipients, with a predominance of E.coli (29 isolates, 29.3%) and A.baumanii (24 isolates, 24.2%). The median age of these 91 recipients was 45 years (interquartile range 35–54). Mortality after the first episode of MDR GNB was 39.6% (36 deaths). The univariate analysis identified the following variables as predictors of MDR GNB-related mortality: lung focus (P = 0.001),nosocomial origin (P = 0.002), graft from donation after cardiac death or deceased donors (P = 0.023), presence of other concomitant bloodstream infection (P < 0.001), temperature of 40 °C or greater at the onset of MDR GNB (P = 0.039), creatinine > 1.5 mg/dl (P = 0.006), albumin < 30 g/L (P = 0.009), platelet count < 50,000/mm³ (P < 0.001), and septic shock (P < 0.001). In the multivariate logistic regression analysis, septic shock (odds ratio (OR) = 160.463, 95% confidence interval (CI) = 19.377–1328.832, P < .001), as well as creatinine > 1.5 mg/dl (OR = 24.498, 95% CI = 3.449–173.998, P = 0.001), nosocomial origin (OR = 23.963, 95% CI = 1.285–46.991, P = 0.033), and presence of other concomitant bloodstream infections (OR = 27.074, 95% CI = 3.937–186.210, P = 0.001) were the variables associated with MDR GNB-related 30-day mortality.

Conclusions

MDR GNB was associated with high morbidity and mortality in ASOT recipients, with a predominant causative organisms being E.coli and A.baumanii. Nosocomial origin, as well as presence of other concomitant bloodstream infections, increased creatinine level and septic shock were the main predictors of MDR GNB-related 30-day mortality.

C7 genotype of the donor may predict early bacterial infection after liver transplantation

Post-transplantation infection causes high mortality and remains a significant challenge. High clinical risk factors for bacterial infection in recipients are often found in critically ill patients. However, for some recipients, bacterial infections are inevitable. It is conceivable that this susceptibility may be related to the genetics of the donor and recipient. Using expression quantitative trait loci (eQTL) analysis, we found that the C7 rs6876739 CC genotypes and mannan-binding lectin (MBL2) gene polymorphisms of liver donors were significantly associated with bacterial infection in recipients. In an extended validation group of 113 patients, donor C7 rs6876739 genetic variation was an independent risk factor for bacterial infection. The donor C7 rs6876739 CC genotype was associated with lower levels of recipient C7 protein, soluble membrane attack complex (MAC), and IL-1β expression compared with the donor C7 rs6876739 TT genotype. In vitro, the MAC significantly triggered NLRP3 inflammasome activation and IL-1β release, suggesting that the mechanism by which C7 defends against bacteria may involve MAC formation, leading to NLRP3 inflammasome activation and IL-1β release. Our findings may be helpful in identifying transplantation recipients at risk of bacterial infection prior to surgery and may contribute to novel infection prevention strategies and the improvement of postoperative outcomes.

Multidrug-resistant Acinetobacter baumannii infections in lung transplant patients in the cardiothoracic intensive care unit

BACKGROUND

Multidrug-resistant (MDR) gram-negative bacteria are a growing threat to solid organ transplantation (SOT) patients in the intensive care unit (ICU). We aimed to examine the mortality rates of gram-negative MDR bacterial infection in SOT patients compared with patient population undergoing other cardiothoracic surgeries and hospitalized under similar ICU conditions.

METHODS

A retrospective study from a single medical center, including patients with MDR Acinetobacter baumannii and carbapenem-resistant Klebsiella pneumoniae infection, hospitalized in the cardiothoracic ICU. Data were collected from computerized databases, and data were verified using the hospitalization files. Microbiological data were provided by the microbiology laboratory.

RESULTS

During the study period, 205 SOT patients and 5031 other patients were hospitalized in the cardiothoracic ICU. Active infection with gram-negative MDR bacteria was identified in 147 patients, of which 37 underwent SOT (18% of total transplant recipients) and 110 underwent another cardiothoracic surgery (2% of total patients who are not transplant recipients). Mortality rates were high among both groups of patients, with no significant difference between them.

CONCLUSIONS

Infection with resistant bacteria is more prevalent among patients following SOT compared with patients following other cardiothoracic surgeries. Mortality is high in all patients regardless of the immunocompromised condition.

Bacterial infection after liver transplantation

Infectious complications are major causes of morbidity and mortality after liver transplantation, despite recent advances in the transplant field. Bacteria, fungi, viruses and parasites can cause infection before and after transplantation. Among them, bacterial infections are predominant during the first two months post-transplantation and affect patient and graft survival. They might cause surgical site infections, including deep intra-abdominal infections, bacteremia, pneumonia, catheter-related infections and urinary tract infections. The risk factors for bacterial infections differ between the periods after transplant, and between centers. Recently, the emergence of multi-drug resistant bacteria is great concern in liver transplant (LT) patients. The instructive data about effects of infections with extended-spectrum beta lactamase producing bacteria, carbapenem-resistant gram-negative bacteria, and glycopeptide-resistant gram-positive bacteria were reported on a center-by-center basis. To prevent post-transplant bacterial infections, proper strategies need to be established based upon center-specific data and evidence from well-controlled studies. This article reviewed the recent epidemiological data, risk factors for each type of infections and important clinical issues in bacterial infection after LT.

Multidrug-resistant bacterial infections after liver transplantation: An ever-growing challenge

Bacterial infections are a leading cause of morbidity and mortality among solid organ transplant recipients. Over the last two decades, various multidrug-resistant (MDR) pathogens have emerged as relevant causes of infection in this population. Although this fact reflects the spread of MDR pathogens in health care facilities worldwide, several factors relating to the care of transplant donor candidates and recipients render these patients particularly prone to the acquisition of MDR bacteria and increase the likelihood of MDR infectious outbreaks in transplant units. The awareness of this high vulnerability of transplant recipients to infection leads to the more frequent use of broad-spectrum empiric antibiotic therapy, which further contributes to the selection of drug resistance. This vicious cycle is difficult to avoid and leads to a scenario of increased complexity and narrowed therapeutic options. Infection by MDR pathogens is more frequently associated with a failure to start appropriate empiric antimicrobial therapy. The lack of appropriate treatment may contribute to the high mortality occurring in transplant recipients with MDR infections. Furthermore, high therapeutic failure rates have been observed in patients infected with extensively-resistant pathogens, such as carbapenem-resistant Enterobacteriaceae, for which optimal treatment remains undefined. In such a context, the careful implementation of preventive strategies is of utmost importance to minimize the negative impact that MDR infections may have on the outcome of liver transplant recipients. This article reviews the current literature regarding the incidence and outcome of MDR infections in liver transplant recipients, and summarizes current preventive and therapeutic recommendations.