Extended-spectrum beta-lactamase-producing bacterial infections in adult solid organ transplant recipients

Molecular Epidemiology, Natural History, and Long-Term Outcomes of Multidrug-Resistant Enterobacterales Colonization and Infections Among Solid Organ Transplant Recipients

BACKGROUND

Multidrug-resistant Enterobacterales (MDR-E), including carbapenem-resistant and third-generation cephalosporin-resistant Enterobacterales (CRE, CefR-E), are major pathogens following solid organ transplantation (SOT).

METHODS

We prospectively studied patients who underwent lung, liver, and small bowel transplant from February 2015 through March 2017. Weekly perirectal swabs (up to 100 days post-transplant) were cultured for MDR-E. Whole-genome sequencing (WGS) was performed on gastrointestinal (GI) tract-colonizing and disease-causing isolates.

RESULTS

Twenty-five percent (40 of 162) of patients were MDR-E GI-colonized. Klebsiella pneumoniae was the most common CRE and CefR-E. Klebsiella pneumoniae carbapenemases and CTX-M were leading causes of CR and CefR, respectively. Thirty-five percent of GI colonizers developed MDR-E infection vs 2% of noncolonizers (P < .0001). The attack rate was higher among CRE colonizers than CefR-E colonizers (53% vs 21%, P = .049). GI colonization and high body mass index were independent risk factors for MDR-E infection (P ≤ .004). Thirty-day mortality among infected patients was 6%. However, 44% of survivors developed recurrent infections; 43% of recurrences were late (285 days to 3.9 years after the initial infection). Long-term survival (median, 4.3 years post-transplant) did not differ significantly between MDR-E-infected and MDR-E-noninfected patients (71% vs 77%, P = .56). WGS phylogenetic analyses revealed that infections were caused by GI-colonizing strains and suggested unrecognized transmission of novel clonal group-258 sublineage CR-K. pneumoniae and horizontal transfer of resistance genes.

CONCLUSIONS

MDR-E GI colonization was common following SOT and predisposed patients to infections by colonizing strains. MDR-E infections were associated with low short- and long-term mortality, but recurrences were frequent and often occurred years after initial infections. Findings provide support for MDR-E surveillance in our SOT program.

Clinical prediction tool for extended-spectrum beta-lactamase-producing enterobacterales as the etiology of a bloodstream infection in solid organ transplant recipients

BACKGROUND

Multidrug-resistant Gram-negative bacterial infections are increasingly common among solid organ transplant (SOT) recipients, leading to challenges in the selection of empiric antimicrobial therapy. We sought to develop a clinical tool to predict which SOT recipients are at high risk for extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales (EB) bloodstream infection (BSI).

METHODS

A multicenter case-control study was performed. The source population included SOT recipients with an EB BSI between 2005 and 2018. Cases were those with ESBL-EB BSI; controls were those with non-ESBL EB BSI. The population was subdivided into derivation and validation cohorts based on study site. The predictive tool was developed in the derivation cohort through iterative multivariable logistic regression analyses that maximized the area under the receiver-operating curve (AUC). External validity was assessed using the validation cohort.

RESULTS

A total of 897 SOT recipients with an EB BSI were included, of which 539 were assigned to the derivation cohort (135, 25% ESBL-EB) and 358 to the validation cohort (221, 62% ESBL-EB). Using multivariable analyses, the most parsimonious model that was predictive of ESBL-EB BSI consisted of 10 variables, which fell into four clinical categories: prior colonization or infection with EB organisms, recent antimicrobial exposures, severity of preceding illness, and immunosuppressive regimen. This model achieved an AUC of 0.81 in the derivation cohort and 0.68 in the validation cohort.

CONCLUSIONS

Though further refinements are needed in additional populations, this tool shows promise for guiding empiric therapy for SOT recipients with EB BSI.

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.

Treatment of multidrug-resistant gram-negative bacilli after solid organ transplant: Outcomes and complications

BACKGROUND

Infections caused by multidrug-resistant gram-negative bacilli (GNB) cause significant morbidity and mortality in solid organ transplant (SOT) recipients.

METHODS

We retrospectively collected data from all SOT recipients at a single center from 1 January 2007 to 15 April 2017 treated for infections caused by multi-drug-resistant GNB. This study examined the effects of specific antibiotics on nephrotoxicity, neurotoxicity, 30-day mortality, and length of stay in the hospital and intensive care unit.

RESULTS

A total of 225 infections were identified among 143 patients. Carbapenem-sensitive organisms were present in 112 (49.8%) infections and were associated with decreased 30-day mortality (OR 0.35, 95% CI 0.16-0.75). Neurotoxicity was associated with polymyxin use with an 8% increase in odds of neurotoxicity per day of exposure (P=.03). There was no relationship between nephrotoxicity and any individual antibiotic class. Increased hospital length-of-stay occurred among patients exposed to aminoglycosides (β-statistic = 0.48 (0.23); P = .04), while there was no relationship between antibiotic class and intensive care unit (ICU) length-of-stay. Mortality at 30 days occurred in 37 infections (16%). Carbapenem exposure was associated with decreased 30-day mortality (OR 0.93; 95% CI 0.90-0.98; P = .02). No other antibiotic class had a significant impact on 30-day mortality.

CONCLUSIONS

Carbapenems appear to be a safe and effective treatment for solid-organ transplant recipients with infections caused by carbapenem-sensitive multidrug-resistant GNB; treatment of carbapenem-resistant gram-negatives remains challenging.

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.

Infections in Liver Transplantation

Liver transplantation has become an important treatment modality for patients with end-stage liver disease/cirrhosis, acute liver failure, and hepatocellular carcinoma. Although surgical techniques and immunosuppressive regimens for liver transplantation have improved significantly over the past 20 years, infectious complications continue to contribute to the morbidity and mortality in this patient population. The use of standardized screening protocols for both donors and recipients, coupled with targeted prophylaxis against specific pathogens, has helped to mitigate the risk of infection in liver transplant recipients. Patients with chronic liver disease and cirrhosis have immunological deficits that place them at increased risk for infection while awaiting liver transplantation. The patient undergoing liver transplantation is prone to develop healthcare-acquired infections due to multidrug-resistant organisms that could potentially affect patient outcomes after transplantation. The complex nature of liver transplant surgery that involves multiple vascular and hepatobiliary anastomoses further increases the risk of infection after liver transplantation. During the early post-transplantation period, healthcare-acquired bacterial and fungal infections are the most common types of infection encountered in liver transplant recipients. The period of maximal immunosuppression that occurs at 1–6 months after transplantation can be complicated by opportunistic infections due to both primary infection and reactivation of latent infection. Severe community-acquired infections can complicate the course of liver transplantation beyond 12 months after transplant surgery. This chapter provides an overview of liver transplantation including indications, donor-recipient selection criteria, surgical procedures, and immunosuppressive therapies. A focus on infections in patients with chronic liver disease/cirrhosis and an overview of the specific infectious complications in liver transplant recipients are presented.

Epidemiological Analysis of Extended-Spectrum Beta-Lactamase-Producing Bacterial Infections in Adult Live Donor Liver Transplant Patients

Introduction:

Bacterial infections are a leading cause of morbidity and mortality in patients receiving solid-organ transplants. Extended-spectrum beta-lactamases (ESBL) pathogens are the most important pathogenic bacteria infecting these patients.

Aim:

This study aims to evaluate for the incidence and characteristics of ESBL-positive organism, to look for the clinical outcomes in ESBL-positive infected cases, and to evaluate and draft the antibiotic policy in posttransplant patients during the first 28 days posttransplant.

Materials and Methods:

This is a retrospective data analysis of liver transplant recipients infected with ESBL culture-positive infections. All the culture sites such as blood, urine, and endotracheal tube aspirates were screened for the first ESBL infection they had and noted. This data were collected till day 28 posttransplant. The antibiotic susceptibility pattern and the most common organism were also noted.

Results:

A total of 484 patients was screened and 116 patients had ESBL-positive cultures. Out of these, 54 patients had infections and 62 patients were ESBL colonizers. The primary infection site was abdominal fluid (40.7%), with Klebsiella accounting for most of the ESBL infections. Colistin was the most sensitive antibiotic followed by tigecycline. The overall mortality was 11.4% and 31 out of 54 ESBL-infected patients died.

Conclusions:

Infections with ESBL-producing organism in liver transplant recipients has a high mortality and very limited therapeutic options.

Urinary tract infections caused by ESBL-producing Enterobacteriaceae in renal transplant recipients: A systematic review and meta-analysis

BACKGROUND

Urinary tract infections (UTIs) are the most common infectious complications among renal transplant recipients (RTR). UTIs caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-PE) have been associated with inferior clinical outcomes and increased financial burden.

METHODS

We performed a systematic review and meta-analysis by searching through the PubMed and EMBASE databases (to May 20, 2016) and identifying studies that reported data on the number of RTR who developed an ESBL-PE UTI.

RESULTS

Our analysis included seven studies, out of 357 non-duplicate articles, that provided data on 2824 patients. Among them, 10% (95% confidence interval [CI] 4%-17%) developed an ESBL-PE UTI over their follow-up periods. The proportion of RTR affected by an ESBL-PE UTI was 2% in North America (95% CI 1%-3%), 5% in Europe (95% CI 4%-6%), 17% in South America (95% CI 10%-27%), and 33% in Asia (95% CI 27%-41%). In addition, patients affected with an ESBL-PE UTI were 2.75-times (95% CI 1.97-3.83) more likely to suffer a recurrent UTI.

CONCLUSIONS

Based on a limited number of studies, one in 10 RTR will develop a UTI caused by an ESBL-PE, and these patients face an almost 3 times greater risk of recurrence. A more rigorous monitoring of RTR, both during and after resolution of their infection, should be evaluated in order to reduce the incidence and the clinical impact of these resistant infections.

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.

Colonization and infection with extended-spectrum beta-lactamase producing Enterobacteriaceae in patients with malignancy

INTRODUCTION

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) constitute a global threat and are prevalent in both nosocomial and community settings. These pathogens have been associated with delays in initiation of appropriate antimicrobial therapy and worse clinical outcomes. Patients with solid or hematologic malignancy represent a high-risk population for both colonization and infection with ESBL-PE. Areas covered: A description of the microbiology and epidemiology of the ESBL-PE is presented. Also, we explore studies on ESBL-PE colonization and infection, and examine areas where future research is needed. Expert commentary: ESBL-PE constitute an increasing threat to patients with malignancy. Unfortunately, substantial geographic variations as well as knowledge gaps in certain regions of the world limit our ability to reach conclusions that are valid globally. Furthermore, there is limited evidence regarding the optimal ways to prevent and manage infections caused by ESBL-PE. Research is urgently needed to elucidate these areas and allow the institution of appropriate infection control and antimicrobial stewardship policies and recommendations.

Colonization with extended-spectrum beta-lactamase-producing Enterobacteriaceae in solid organ transplantation: A meta-analysis and review

BACKGROUND

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) may cause severe infections, often preceded by ESBL-E gastrointestinal (GI) colonization.

METHODS

We conducted a review of the literature, investigating the prevalence of ESBL-E GI colonization in solid organ transplant (SOT) patients and the risk for subsequent ESBL-E infection. We searched the PubMed and EMBASE databases (to April 1, 2016) looking for studies that contained data on ESBL-E colonization among transplant patients.

RESULTS

Of 341 non-duplicate citations, four studies reporting data on 1089 patients fulfilled our inclusion criteria. Among them, the pooled prevalence for ESBL-E colonization was 18% (95% confidence interval [CI] 5%-36%). Stratifying by transplant type, we identified an ESBL-E colonization rate of 17% (95% CI 3%-39%) among liver transplant recipients and 24% (single report) among kidney transplant recipients.

CONCLUSIONS

Among SOT patients, approximately one in five patients is colonized with ESBL-E, although this finding may be skewed by reporting bias from centers with high ESBL-E prevalence. ESBL-E screening in SOT patients should be considered and evaluated in future studies.

Solid organ transplant patients: are there opportunities for antimicrobial stewardship?

OBJECTIVE

Rising incidence of Clostridium difficile and multidrug-resistant organisms' infections and a dwindling development of new antimicrobials are an impetus for antimicrobial stewardship in organ transplant recipients. We sought to understand antimicrobial prescribing practices and identify opportunities for interdisciplinary collaboration among the transplant, antimicrobial stewardship, and infectious diseases teams.

METHODS

In 2013, two assessors conducted four real-time audits on all antimicrobial therapy in transplant patients, assessing each regimen against stewardship principles established by the Centers for Disease Prevention and Control, supplemented by applicable transplant-specific infection guidelines. Chi-square test was used to compare stewardship-concordant and stewardship-discordant audit results relative to transplant infectious diseases consultation.

RESULTS

Analysis was performed on 176 audits. Fifty-eight percent (103/176) received at least one antimicrobial, of which 69.9% (72/103) were stewardship-concordant. Infections were confirmed or suspected in 52.3% (92/176). Of those, 98.9% (91/92) received antimicrobials, and 41.8% (38/91) were prescribed by transplant clinicians. Infectious diseases consultation was associated with more stewardship-concordant prescriptions (78.5% vs. 59.6%, p = 0.03). The most common stewardship-discordant categories were lack of de-escalation, empiric antimicrobial spectrum being too broad, and therapy duration being too long.

CONCLUSIONS

Opportunities exist for antimicrobial stewardship in transplant recipients, especially those who do not require infectious diseases consultation.

Risk factors and outcome of infections with Klebsiella pneumoniae carbapenemase-producing K. pneumoniae in kidney transplant recipients

INTRODUCTION

Solid organ transplant recipients are especially susceptible to healthcare-associated infections with Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp-HAIs). The aim of the study was to evaluate risk factors and outcome of these infections in kidney transplant recipients.

METHODS

This was a retrospective cohort of kidney transplant (KTx) recipients between January 2009 and December 2013. Cases were defined as patients who developed KPC-Kp-HAI, confirmed by PCR for bla( KPC) gene after KTx during the study period. We analysed variables related to recipient; induction immunosuppressant therapy; delayed graft function; use of invasive devices; SOFA score on the first day of infection; type of therapy; time from positive culture to appropriate antimicrobial therapy; bacteraemia; and concomitant infection. Outcome measures were the occurrence of KPC-Kp-HAI and 30-day mortality after KPC-Kp-HAI.

RESULTS

A total of 1,101 were submitted to KTx in the period, 21 patients were classified as infected with KPC-Kp. Another ten patients had KPC-Kp-HAI in the period and were transplanted before 2009. Of those 31 patients, 48.4 % showed evidence of prior colonization and 38.7 % had bacteraemia. The most common site of infection was the surgical wound. Risk factors for KPC-Kp-HAI were multi-organ transplantation and the use of a ureteral stent. Eight of the infected patients experienced recurrence of the infection. The 30-day mortality rate was 41.9 %. Survival was significantly lower among the patients with KPC-Kp-HAI (72 vs. 89.1 %; P = 0.002). The only risk factor independently associated with 30-day mortality was an elevated SOFA score on the first day of infection.

CONCLUSIONS

In KTx recipients, the occurrence of KPC-Kp-HAI was related to invasive devices and type of transplant; these infections had a high rate of recurrence and reduced survival after KTx.

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.

Diagnostic bronchoscopy in solid-organ and hematopoietic stem cell transplantation

Fiberoptic bronchoscopy is a valuable diagnostic tool in solid-organ and hematopoietic stem cell transplant recipients presenting with a range of pulmonary complications. This article provides a comprehensive overview of the utility and potential adverse effects of diagnostic bronchoscopy for transplant recipients. Recommendations are offered on the selection of patients, the timing of bronchoscopy, and the samples to be obtained across the spectrum of suspected pulmonary complications of transplantation. Based on review of the literature, the authors recommend early diagnostic bronchoscopy over empiric treatment in transplant recipients with evidence of certain acute, subacute, or chronic pulmonary processes. This approach may be most critical when an underlying infectious etiology is suspected. In the absence of prompt diagnostic information on which to base effective treatment, the risks associated with empiric antimicrobial therapy, including medication side effects and the development of antibiotic resistance, compound the potential harm of delaying targeted management.

Transplantation-associated long-term immunosuppression promotes oral colonization by potentially opportunistic pathogens without impacting other members of the salivary bacteriome

Solid-organ transplant recipients rely on pharmacological immunosuppression to prevent allograft rejection. The effect of such chronic immunosuppression on the microflora at mucosal surfaces is not known. We evaluated the salivary bacterial microbiome of 20 transplant recipients and 19 nonimmunosuppressed controls via 454 pyrosequencing of 16S rRNA gene amplicons. Alpha-diversity and global community structure did not differ between transplant and control subjects. However, principal coordinate analysis showed differences in community membership. Taxa more prevalent in transplant subjects included operational taxonomic units (OTUs) of potentially opportunistic Gammaproteobacteria such as Klebsiella pneumoniae, Pseudomonas fluorescens, Acinetobacter species, Vibrio species, Enterobacteriaceae species, and the genera Acinetobacter and Klebsiella. Transplant subjects also had increased proportions of Pseudomonas aeruginosa, Acinetobacter species, Enterobacteriaceae species, and Enterococcus faecalis, among other OTUs, while genera with increased proportions included Klebsiella, Acinetobacter, Staphylococcus, and Enterococcus. Furthermore, in transplant subjects, the dose of the immunosuppressant prednisone positively correlated with bacterial richness, while prednisone and mycophenolate mofetil doses positively correlated with the prevalence and proportions of transplant-associated taxa. Correlation network analysis of OTU relative abundance revealed a cluster containing potentially opportunistic pathogens as transplant associated. This cluster positively correlated with serum levels of C-reactive protein, suggesting a link between the resident flora at mucosal compartments and systemic inflammation. Network connectivity analysis revealed opportunistic pathogens as highly connected to each other and to common oral commensals, pointing to bacterial interactions that may influence colonization. This work demonstrates that immunosuppression aimed at limiting T-cell-mediated responses creates a more permissive oral environment for potentially opportunistic pathogens without affecting other members of the salivary bacteriome.

Losing ground: multidrug-resistant bacteria in solid-organ transplantation

PURPOSE OF REVIEW

Multidrug-resistant (MDR) bacteria can cause serious infections in solid-organ transplant recipients. This review focuses on the role of MDR bacteria in posttransplant infections.

RECENT FINDINGS

The incidence of MDR bacterial infections among solid-organ transplant recipients is increasing steadily. There is wide variability in the specific MDR bacteria causing infection based on the organ transplanted, geography, timing with respect to transplantation, and additional risk factors. Rarely these infections can be transmitted via the transplanted organ. Prompt recognition and early appropriate treatment of MDR bacterial infections are especially critical in this immunosuppressed population. In order to promptly initiate appropriate antimicrobial therapy for these organisms, high-risk patients should receive appropriate broad-spectrum antibiotics.

SUMMARY

MDR bacterial infections vary widely and require careful antibiotic selection to reduce mortality.