Association between nasal carriage of Staphylococcus aureus and infection in liver transplant recipients

Bacterial and Viral Infections in Liver Transplantation: New Insights from Clinical and Surgical Perspectives

End-stage liver disease patients undergoing liver transplantation are prone to develop numerous infectious complications because of immunosuppression, surgical interventions, and malnutrition. Infections in transplant recipients account for the main cause of mortality and morbidity with rates of up to 80%. The challenges faced in the early post-transplant period tend to be linked to transplant procedures and nosocomial infections commonly in bloodstream, surgical, and intra-abdominal sites. Viral infections represent an additional complication of immunosuppression; they can be donor-derived, reactivated from a latent virus, nosocomial or community-acquired. Bacterial and viral infections in solid organ transplantation are managed by prophylaxis, multi-drug resistant screening, risk assessment, vaccination, infection control and antimicrobial stewardship. The aim of this review was to discuss the epidemiology of bacterial and viral infections in liver transplants, infection control issues, as well as surgical frontiers of ex situ liver perfusion.

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.

Methicillin-resistant Staphylococcus aureus carriers are vulnerable to bloodstream infection after living donor liver transplantation

BACKGROUND

Bloodstream infection (BSI) is a life-threatening complication after living donor liver transplantation (LDLT). We aimed to explore the incidence and predisposing factors of BSI at our institution.

METHODS

We conducted a retrospective cohort analysis on all consecutive adults with BSI within 6 months after LDLT performed between 2005 and 2016. For antimicrobial prophylaxis, ampicillin/sulbactam, cefotaxime, and micafungin were administered. From 2011, methicillin-resistant Staphylococcus aureus (MRSA) carriers were decolonized using mupirocin ointment and chlorhexidine gluconate soap. Risk factors for BSI were identified by uni- and multivariate logistic regression.

RESULTS

Of a total of 106 LDLTs, 42 recipients (40%) suffered BSI. The BSI group demonstrated significantly higher in-hospital mortality rates compared with the non-BSI group (24% vs. 7%, P = .01). We identified MRSA carrier (odds ratio [OR], 19.1; P < .001), ABO incompatibility (OR, 2.9; P = .03), and estimated glomerular filtration rate <30 mL/min/1.73m² (OR, 15.8; P = .02) as independent risk factors for BSI. Decolonization treatment for MRSA carriers did not reduce the incidence of all-cause BSI but reduced the frequency of BSI caused by MRSA.

CONCLUSION

To our knowledge, for the first time, MRSA carriers were revealed to be highly vulnerable to BSI after LDLT.

Surgical site infections: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of post-operative surgical site infections (SSIs) in solid organ transplantation. SSIs are a significant cause of morbidity and mortality in SOT recipients. Depending on the organ transplanted, SSIs occur in 3%-53% of patients, with the highest rates observed in small bowel/multivisceral, liver, and pancreas transplant recipients. These infections are classified by increasing invasiveness as superficial incisional, deep incisional, or organ/space SSIs. The spectrum of organisms implicated in SSIs in SOT recipients is more diverse than the general population due to other important factors such as the underlying end-stage organ failure, immunosuppression, prolonged hospitalizations, organ transportation/preservation, and previous exposures to antibiotics in donors and recipients that could predispose to infections with multidrug-resistant organisms. In this guideline, we describe the epidemiology, clinical presentation, differential diagnosis, potential pathogens, and management. We also provide recommendations for the selection, dosing, and duration of peri-operative antibiotic prophylaxis to minimize post-operative SSIs.

Management of bacterial and fungal infections in end stage liver disease and liver transplantation: Current options and future directions

Patients with liver cirrhosis are susceptible to infections due to various mechanisms, including abnormalities of humoral and cell-mediated immunity and occurrence of bacterial translocation from the intestine. Bacterial infections are common and represent a reason for progression to liver failure and increased mortality. Fungal infections, mainly caused by Candida spp., are often associated to delayed diagnosis and high mortality rates. High level of suspicion along with prompt diagnosis and treatment of infections are warranted. Bacterial and fungal infections negatively affect the outcomes of liver transplant candidates and recipients, causing disease progression among patients on the waiting list and increasing mortality, especially in the early post-transplant period. Abdominal, biliary tract, and bloodstream infections caused by Gram-negative bacteria [e.g., Enterobacteriaceae and Pseudomonas aeruginosa (P. aeruginosa)] and Staphylococcus spp. are commonly encountered in liver transplant recipients. Due to frequent exposure to broad-spectrum antibiotics, invasive procedures, and prolonged hospitalizations, these patients are especially at risk of developing infections caused by multidrug resistant bacteria. The increase in antimicrobial resistance hampers the choice of an adequate empiric therapy and warrants the knowledge of the local microbial epidemiology and the implementation of infection control measures. The main characteristics and the management of bacterial and fungal infections in patients with liver cirrhosis and liver transplant recipients are presented.

Methicillin-resistant Staphylococcus aureus bacteremia among liver transplant recipients: epidemiology and associated risk factors for morbidity and mortality

Bacteremia due to Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), complicates the clinical course of liver transplantation and is associated with high morbidity and mortality. Intravascular catheters had been reported to be the most frequent source of MRSA bacteremia. Among bacteremic liver recipients, 26.3%-100% of S. aureus were MRSA. Previous studies identified pre-transplant and post-transplant acquired S. aureus carriage, greater severity of liver disease, hepatocellular carcinoma and infection with immuno-modulatory viruses as predictors of S. aureus bacteremia in liver recipients. MRSA bacteremia accompanied by pneumonia and abdominal infections was related to mortality. Vancomycin, as well as daptomycin, is a first-line antibiotic for MRSA bacteremia. The purpose of this review is to better understand the characteristics of MRSA bacteremia by summarizing the epidemiology and antimicrobial resistance of S. aureus, the primary source, and related risk factors for morbidity and mortality of MRSA bacteremia. We have also explored the diagnostic, therapeutic and preventive measures for MRSA bacteremia to improve the outcomes of liver recipients.

Impact of oral gut decontamination on Staphylococcus aureus colonisation in patients undergoing allogeneic haematopoietic stem cell transplantation

Recipients of allogeneic haematopoietic stem cell transplantation (allo-HSCT) are severely immunocompromised and are at increased risk of infection. In this prospective, observational, single-centre study including 110 allo-HSCT recipients, the rate of Staphylococcus aureus colonisation was reduced from 11.8% to 0% (P <0.001) following peritransplant oral gut decontamination. No invasive S. aureus infections were observed.

Infection Prevention and Control Issues After Solid Organ Transplantation

Infections are an important cause of morbidity and mortality in solid organ transplant recipients. Consequently, infection prevention is an essential component of any organ transplant program. Given their frequent and often prolonged contact with the healthcare system, solid organ transplant recipients are at high risk for healthcare-associated infections, including those caused by antibiotic-resistant organisms. In this chapter we review several different healthcare-associated infections of importance to transplant recipients, including those caused by bacterial, viral, and fungal organisms. We also describe infection prevention and control strategies applicable to this patient population. These practices focus on clinical interventions and environmental controls designed to prevent the spread of potentially pathogenic organisms in the healthcare setting. We also describe post-exposure interventions applicable to solid organ transplant recipients exposed to potential pathogens in order to reduce their risk of subsequent infection.

Staphylococcus aureus bacteremias following liver transplantation: a clinical analysis of 20 cases

Background

To describe the incidence, clinical characteristics, and outcomes of Staphylococcus aureus bacteremia after liver transplantation and investigate the drug resistance of S. aureus to frequently used antibiotics to provide evidence for clinical prevention and therapy.

Materials and methods

In a double-center retrospective study, blood cultures positive for S. aureus were obtained from January 1, 2001 to December 31, 2014. The BACTEC 9120 blood culture system and the Vitek-2 system were used to process blood samples and identify species, respectively. We also collected these patients’ data to confirm clinical and laboratory characteristics.

Results

Twenty of 275 (7.3%) liver recipients developed S. aureus bacteremia during the study period. The median time to the onset of S. aureus bacteremias was 6 days after liver transplantation and all episodes of bacteremias were early onset. The lung was the most common source of primary infection, followed by the intra-abdominal/biliary tract. A total of nine (45%) liver recipients died due to S. aureus bacteremias. Of these 20 S. aureus cases, 80% were methicillin-resistant. S. aureus was highly resistant to erythromycin and penicillin (resistance rate >90%). No S. aureus resistant to glycopeptides and oxazolidone antibiotics was observed. There were seven (35%) liver recipients with an inappropriate antibiotic therapy. Between the periods of 2001–2007 and 2008–2014, the distribution of methicillin-resistant S. aureus was not significantly different (P=1.000). Pneumonia as a predominant primary source, a high body temperature, abnormal blood pressure, and decreased platelets, which occurred in the early period after liver transplantation, as well as high morbidity and mortality, were the main characteristics of S. aureus bacteremias.

Conclusion

S. aureus led to severe bacteremias in liver recipients, with high morbidity and mortality, and the majority of them comprised methicillin-resistant S. aureus.

Clinical significance of surveillance culture in liver transplant recipients

BACKGROUND

Routine microbiologic surveillance is a method of infection control, but its clinical significance in transplant recipients is not known. We analyzed microbiologic data to evaluate the influence of cultured microorganisms between the point of surveillance and infectious episodes in liver transplant recipients.

METHODS

We performed surveillance culture for sputum and peritoneal fluid in liver transplant recipients from January 2009 to December 2011, at the time of transplantation (T1), 5 days (T2), and 10 days (T3) postoperatively.

RESULTS

Of the 179 recipients, 32.9% had a positive sputum culture result and 37.4% had a positive peritoneal culture result during surveillance. In the culture surveillance of sputum, 37 organisms were isolated from 35 recipients at T1, and the most common organism was Staphylococcus aureus (n = 13). At T2, 45 organisms were isolated from 39 recipients, including Klebsiella pneumoniae (n = 10), S aureus (n = 8), and Acinetobacter baumannii (n = 6). At T3, 18 organisms were isolated from 15 patients, including Stenotrophomonas maltophilia (n = 5) and K pneumonia (n = 4). In the peritoneal fluid, 11 organisms were isolated from 10 recipients at T1, including Pseudomonas aeruginosa (n = 2) and Enterococcus species (n = 2). At T2, 39 organisms were isolated from 36 recipients, including coagulase-negative Staphylococcus species (CNS; n = 8) and Enterococcus species (n = 7). At T3, 54 organisms were isolated from 51 recipients, including CNS (n = 17) and Candida species (n = 8). Among the 59 patients with positive culture results for sputum surveillance, 16.9% developed pneumonia caused by the same organisms. Among the 67 patients with positive peritoneal fluid culture, 16.4% developed an intra-abdominal infection caused by the same organisms cultured. The recipients with positive surveillance culture had a higher risk of pneumonia (20.3% [12/59] vs 1.6% [2/120]; P < .001) and intra-abdominal infection (31.3% [21/67] vs 18.7% [21/112]; P = .05).

CONCLUSIONS

Periodic microbiologic surveillance may be useful in the prediction of post-transplantation pneumonia and intra-abdominal infection and could offer a potential target for empirical antimicrobial therapy in cases of infection.

Colonization With Methicillin-Resistant Staphylococcus aureus in ICU Patients Morbidity, Mortality, and Glycopeptide Use

Objective:

To determine the impact of methicillin-resis-tant Staphylococcus aureus (MRSA) colonization on the occurrence of S aureus infections (methicillin-resistant and methicillin-suscep-tible), the use of glycopeptides, and outcome among intensive care unit (ICU) patients.

Design:

Prospective observational cohort survey.

Setting:

A medical-surgical ICU with 10 single-bed rooms in a 460-bed, tertiary-care, university-affiliated hospital.

Patients:

A total of 1,044 ICU patients were followed for the detection of MRSA colonization from July 1, 1995, to July, 1 1998.

Methods:

MRSA colonization was detected using nasal samples in all patients plus wound samples in surgical patients within 48 hours of admission or within the first 48 hours of ICU stay and weekly thereafter. MRSA infections were defined using Centers for Disease Control and Prevention standard definitions, except for ventilator-associated pneumonia and catheter-related infections, which were defined by quantitative distal culture samples.

Results:

One thousand forty-four patients (70% medical patients) were included in the analysis. Mean age was 61±18 years; mean Simplified Acute Physiologic Score (SAPS) II was 36.4±20; and median ICU stay was 4 (range, 1-193) days. Two hundred thirty-one patients (22%) died in the ICU. Fifty-four patients (5.1%) were colonized with MRSA on admission, and 52 (4.9%) of 1,044 acquired MRSA colonization in the ICU. Thirty-five patients developed a total of 42 S aureus infections (32 MRSA, 10 methi-cillin-susceptible). After factors associated with the development of an S aureus infection were adjusted for in a multivariate Cox model (SAPS II >36: hazard ratio [HR], 1.64; P=.09; male gender: HR, 2.2; P=.05), MRSA colonization increased the risk of S aureus infection (HR, 3.84; P=.0003). MRSA colonization did not influence ICU mortality (HR, 1.01; P=.94). Glycopeptides were used in 11.4% of the patients (119/1,044) for a median duration of 5 days. For patients with no colonization, MRSA colonization on admission, and ICU-acquired MRSA colonization, respectively, glycopeptide use per 1,000 hospital days was 37.7, 235.2, and 118.3 days. MRSA colonization per se increased by 3.3-fold the use of glycopeptides in MRSA-colonized patients, even when an MRSA infection was not demonstrated, compared to non-colonized patients.

Conclusions:

In our unit, MRSA colonization greatly increased the risk of S aureus infection and of glycopeptide use in colonized and non-colonized patients, without influencing ICU mortality. MRSA colonization influenced glycopeptide use even if an MRSA infection was not demonstrated; thus, an MRSA control program is warranted to decrease vancomycin use and to limit glycopeptide resistance in gram-positive cocci.

Bloodstream infections among solid organ transplant recipients: Epidemiology, microbiology, associated risk factors for morbility and mortality

Bloodstream infections (BSIs) remain important causes of morbidity and mortality among solid organ transplant (SOT) recipients and still threaten the success of SOT. In general, among SOT recipients, risk factors for BSIs are associated with prior ICU admission, catheterization, older recipient or donor age…etc. Pulmonary focus, nosocomial source of BSIs, lack of appropriate antibiotic therapy and other variables have significant impacts on BSIs-related mortality in SOT. Most of BSIs in SOT are caused by gram-negative bacteria. However, all aspects including microbiological spectrum, morbidity and mortality rates, risk factors of BSIs and BSIs-related death depend on the type of transplantation. The purpose of this review is to summarize the epidemiology, microbiologic features including antimicrobial resistance of organisms, and associated risk factors for morbidity and mortality of BSIs according to different type of transplantation to better understand the characteristics of BSIs and improve the outcomes after SOT.

MRSA and VRE colonization in solid organ transplantation: a meta-analysis of published studies

The burden of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE) colonization among the increasing number of solid organ transplant patients has not been systematically explored. We searched PubMed and EMBASE for pertinent articles, performed a meta-analysis of prevalence across eligible studies and estimated the risk of ensuing MRSA or VRE infections relative to colonization status. We stratified effects in the pretransplant and posttransplant period. Twenty-three studies were considered eligible. Seventeen out of 23 (74%) referred to liver transplants. Before transplantation, the pooled prevalence estimate for MRSA and VRE was 8.5% (95% confidence interval [CI] 3.2–15.8) and 11.9% (95% CI 6.8–18.2), respectively. MRSA estimate was influenced by small studies and was lower (4.0%; 95% CI 0.4–10.2) across large studies (>200 patients). After transplantation, the prevalence estimates were 9.4% (95% CI 3.0–18.5) for MRSA and 16.2% (95% CI 10.7–22.6) for VRE. Pretransplant as well as posttransplant MRSA colonization significantly increased the risk for MRSA infections (pooled risk ratio [RR] 5.51; 95% CI 2.36–12.90 and RR 10.56; 95% CI 5.58–19.95, respectively). Pretransplant and posttransplant VRE colonization were also associated with significant risk of VRE infection (RR 6.65; 95% CI 2.54–17.41 and RR 7.93; 95% CI 2.36–26.67, respectively). Solid organ transplantation is a high-risk setting for MRSA and VRE colonization, and carrier state is associated with infection. Upgraded focus in prevention and eradication strategies is warranted.

Clinical significance of methicillin-resistant Staphylococcus aureus colonization on hospital admission: one-year infection risk

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization among inpatients is a well-established risk factor for MRSA infection during the same hospitalization, but the long-term risk of MRSA infection is uncertain. We performed a retrospective cohort study to determine the one-year risk of MRSA infection among inpatients with MRSA-positive nasal polymerase chain reaction (PCR) tests confirmed by positive nasal culture (Group 1), patients with positive nasal PCR but negative nasal culture (Group 2), and patients with negative nasal PCR (Group 3).

METHODOLOGY/PRINCIPAL FINDINGS

Subjects were adults admitted to a four-hospital system between November 1, 2006 and March 31, 2011, comprising 195,255 admissions. Patients underwent nasal swab for MRSA PCR upon admission; if positive, nasal culture for MRSA was performed; if recovered, MRSA was tested for Panton-Valentine Leukocidin (PVL). Outcomes included MRSA-positive clinical culture and skin and soft tissue infection (SSTI). Group 1 patients had a one-year risk of MRSA-positive clinical culture of 8.0% compared with 3.0% for Group 2 patients, and 0.6% for Group 3 patients (p<0.001). In a multivariable model, the hazard ratios for future MRSA-positive clinical culture were 6.52 (95% CI, 5.57 to 7.64) for Group 1 and 3.40 (95% CI, 2.70 to 4.27) for Group 2, compared with Group 3 (p<0.0001). History of MRSA and concurrent MRSA-positive clinical culture were significant risk factors for future MRSA-positive clinical culture. Group 1 patients colonized with PVL-positive MRSA had a one-year risk of MRSA-positive clinical culture of 10.1%, and a one-year risk of MRSA-positive clinical culture or SSTI diagnosis of 21.7%, compared with risks of 7.1% and 12.5%, respectively, for patients colonized with PVL-negative MRSA (p = 0.04, p = 0.005, respectively).

CONCLUSIONS/SIGNIFICANCE

MRSA nasal colonization is a significant risk factor for future MRSA infection; more so if detected by culture than PCR. Colonization with PVL-positive MRSA is associated with greater risk than PVL-negative MRSA.

Risk factors for methicillin-resistant Staphylococcus aureus bacteraemia differ depending on the control group chosen

Methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia cause significant morbidity and mortality in hospitalized patients. Using a nested case-control design, 204 MRSA bacteraemia cases were compared to 301 unmatched methicillin-susceptible Staphylococcus aureus (MSSA) bacteraemia controls and were matched 1:2 with non-infected controls. The independent risk factors for MRSA bacteraemia compared to MSSA bacteraemia were older age (P = 0·048), major organ transplant during current hospital stay (P = 0·016) and quinolone use (P = 0·016). Cases were more likely than non-infected controls to have renal failure (P = 0·003), cirrhosis (P = 0·013), and a central venous catheter (P = 0·003) after controlling for other risk factors. This large case-control study made it possible to assess risk factors for MRSA bacteraemia using two sets of controls and showed that risk factors differed greatly depending on the control group chosen. These results confirm the need for careful selection of appropriate control groups and the need to carefully adjust for underlying severity of illness.

[Daptomycin in Gram-positive bacterial infections in oncohematological patients and transplant recipients]

Gram-positive infections are a major cause of morbidity and mortality in oncohematological patients and transplant recipients. The most frequently isolated Gram-positive organisms are the coagulase-negative staphylococci, Staphylococcus aureus and Enterococcus spp., and viridans group streptococci. Antibiotic resistance in these organisms is increasing and poses a challenge to clinicians. Daptomycin is rapidly bactericidal against a broad spectrum of gram-positive bacteria, including strains resistant to other drugs. The present article reviews some aspects of Gram-positive infections in these immunocompromised patients and provides a detailed analysis of experience with daptomycin in the treatment of these infections.

Staphylococcus aureus infections after liver transplantation

BACKGROUND

More data on the risk factors and outcomes after Staphylococcus aureus infections in liver transplantation are needed.

METHODS

Liver recipients with S. aureus infections (cases) were retrospectively identified and compared to gender-, age-, and transplant type-matched (1:2) non-S. aureus-infected controls. Risk factors associated with S. aureus infections were identified by conditional logistic regression analysis.

RESULTS

We evaluated 51 patients (median age 52 years). First S. aureus infections developed at a median time of 29 days after transplantation, with 52.94% of them in the first month; 88.24% were nosocomial, 41.18% were polymicrobial, and 47.06% were caused by methicillin-resistant S. aureus (MRSA). Surgical site infections represented 58.82% and bacteremia 23.53%. By univariate analysis, patients with S. aureus infections were intubated more frequently (odds ratio [OR] 26.92, 95% confidence interval [CI] 3.23-3,504.15, p = 0.0006), had a central line (OR 11.69, 95% CI 1.42-95.9, p = 0.02), or recent surgery (OR 26.92, 95% CI 3.23-3,504.15, p = 0.0006) compared with controls. By multivariate analysis, subjects who underwent surgery within 2 weeks prior to infection had a 26.9 times higher risk of developing S. aureus infection (95% CI 3.23-3,504.15, p = 0.0006); these results were adjusted for matched criteria. S. aureus infections did not affect graft or patient survival, but the study was not powered for such outcomes.

CONCLUSION

Only recent surgical procedure was found to be a significant independent risk factor for S. aureus infections after liver transplantation.

Infections in liver transplant recipients

Liver transplantation is a standard life-saving procedure for the treatment of many end-stage liver diseases. The success of this procedure may be limited by infectious complications. In this article, we review the contemporary state of infectious complications during the post-operative period, with particular emphasis on those that occur most commonly during the first 6 mo after liver transplantation. Bacteria, and less commonly Candida infections, remain the predominant pathogens during the immediate post-operative period, especially during the first month, and infections caused by drug-resistant strains are emerging. Infections caused by cytomegalovirus and Aspergillus sp. present clinically during the "opportunistic" period characterized by intense immunosuppression. As newer potent immunosuppressive therapies with the major aim of reducing allograft rejection are developed, one potential adverse effect is an increase in certain infections. Hence, it is essential for liver transplant centers to have an effective approach to prevention that is based on predicted infection risk, local antimicrobial resistance patterns, and surveillance. A better understanding of the common and most important infectious complications is anticipated to lead to improvements in quality of life and survival of liver transplant recipients.

Early-onset pneumonia after liver transplantation: microbiological findings and therapeutic consequences

Early-onset hospital-acquired pneumonia (E-HAP) is one of the leading causes of sepsis and mortality after liver transplantation (LT). The appropriate antimicrobial therapy is crucially important for surviving sepsis in this context. The aim of this study was to analyze microbiological findings, associated factors, and optimal antibiotic regimens for E-HAP after LT. Patients demonstrating E-HAP in a single-center cohort of 148 LT recipients were prospectively detected. The diagnosis of pneumonia relied on a combination of supportive clinical findings and a positive culture of a lower respiratory tract sample. E-HAP was considered present if pneumonia occurred within 6 days of intensive care unit (ICU) admission after LT. Twenty-three patients (15.5%) developed E-HAP, which were caused by 36 pathogens (61.1% were gram-negative bacilli, and 33.3% were classified as hospital-acquired). For patients who developed E-HAP, the duration of mechanical ventilation and the ICU stay were significantly longer. Despite a trend toward higher mortality at any time in the E-HAP group, there was no significant difference in mortality between patients with E-HAP and patients without E-HAP. Lactatemia, vasopressor requirements, Simplified Acute Physiology Score II (SAPS II) score on ICU admission, and mechanical ventilation lasting more than 48 hours after LT were associated with E-HAP. Combinations of broad-spectrum β-lactams and aminoglycosides were active against more than 91% of the encountered pathogens. However, antibiotic de-escalation was possible in more than one-third of cases after identification of the pathogens. In conclusion, E-HAP after LT is a severe condition that appears to be influenced by physiological derangements induced by the surgery, such as lactatemia, vasopressor requirements, and mechanical ventilation requirements, as well as the postoperative SAPS II score. At the time of treatment initiation, an antimicrobial regimen usually proposed for late-onset pneumonia should be followed.

Comparison of flocked and rayon swabs for detection of nasal carriage of Staphylococcus aureus among pathology staff members

Comparison of flocked swabs (E-swabs; Copan) to the standard rayon swabs (Copan) was undertaken for detection of Staphylococcus aureus nasal carriage among staff at Dorevitch Pathology in Heidelberg, Melbourne, Australia. Among 100 volunteers, 36 were found to be colonized with S. aureus by one or both swab results. The prevalence detected by E-swabs was 35%, and the prevalence through rayon swabs was 34% (95% confidence interval [CI] for the difference in proportions, -12 to 14). Thirty-three volunteers tested positive with both types of swabs, while 2 were detected on E-swabs alone and another on rayon swab testing alone. There was no evidence of a significant difference in carriage detected by E-swabs or rayon swabs.

The outcomes of methicillin-resistant Staphylococcus aureus infection after living donor liver transplantation in a Japanese center

OBJECTIVE

The objective of this study is to present results from our review of methicillin-resistant Staphylococcus aureus (MRSA) infection in living-donor liver transplant (LDLT) recipients.

METHODS

Seventy patients with primary LDLT between August 1997 and May 2007 were retrospectively reviewed.

RESULTS

Overall, 9 patients (12.9%) encountered various kinds of MRSA infection after transplantation [peritonitis (6), bacteremia (6), pneumonia (3), wound infection (3), cholangitis (1)]; 4 of these 9 patients died. Of these 4 expired patients, 3 were highly urgent cases with very poor pretransplant status under ventilator support. In one patient, linezolid was effective after teicoplanin failure for severe systemic MRSA infections (bacteremia, peritonitis, cholangitis, pneumonia, and enteritis). Of the 4 patients in whom MRSA was isolated only in a nasal swab before transplantation, none developed MRSA infection after transplantation with a 3-day course of mupirocin prophylaxis.

CONCLUSIONS

MRSA infection was a contributing factor in death after transplantation in cases with poor pretransplant status. Linezolid was effective even for treating systemic MRSA infection after LDLT. A short course of mupirocin prophylaxis seemed to be effective and did not have any adverse effects.

Microbial epidemiology and outcome of bloodstream infections in liver transplant recipients: an analysis of 259 episodes

Bloodstream infections (BSIs) are a major cause of mortality in liver transplant recipients. The incidence, microbiology, and outcome of BSIs in the first year after liver transplantation were analyzed in 704 patients who underwent transplantation at a single center between 1997 and 2007. BSIs occurred in 205 (29.1%) of the 704 patients. Overall, 259 episodes were documented, and they resulted in an incidence rate of 36.8%. Of these episodes, 39.4%, 27.8%, 17%, and 15.8% occurred in the very early period (< or = 10 days after liver transplantation), the early period (days 11-30), the intermediate period (days 31-90), and the late period (days 91-365), respectively. The most frequent pathogens were Enterobacteriaceae members (41%), Staphylococcus aureus (19.8%), enterococci (13.1%), Pseudomonas aeruginosa (8.8%), and yeasts (7.1%). The median time of onset ranged from 7 days for methicillin-resistant S. aureus to 25 days for Enterobacteriaceae. Mortality at 15 days after BSIs was 16.2%. Kaplan-Meier survival curves showed that patients with BSIs had a significantly higher 1-year mortality rate than those without BSIs (28.3% versus 16.6%, P < 0.001 with the log-rank test). When the time of BSI onset was considered, 1-year mortality was significantly associated with very early and early episodes (P < 0.001) but not with intermediate and late episodes (P = 0.47). In conclusion, BSIs are frequent and early complications after liver transplantation and are mostly caused by gram-negative bacilli. A BSI in the first posttransplant month is a significant predictor of 1-year survival.

Acquisition of methicillin-resistant Staphylococcus aureus after living donor liver transplantation: a retrospective cohort study

BACKGROUND

The incidence and risk factors of methicillin-resistant Staphylococcus aureus (MRSA) acquisition after living donor liver transplantation (LDLT) are unclear. The aim of the present study was to assess the incidence and to analyze the risk factors for the acquisition of MRSA after LDLT in adults by multivariate analysis.

METHODS

We retrospectively reviewed the data from 158 adult patients that underwent LDLT at the Tokyo University Hospital. The microbiologic and medical records of the patients from admission to 3 months after LDLT were reviewed. Uni- and multivariate analyses were performed to identify the risk factors for postoperative acquisition of MRSA.

RESULTS

Postoperative MRSA acquisition was detected in 35 of 158 patients by median postoperative day 18. Age (>or= 60 y) and perioperative dialysis and/or apheresis predicted postoperative MRSA acquisition by multivariate analysis. In contrast, postoperative use of fluoroquinolone was negatively associated with acquisition of MRSA.

CONCLUSION

MRSA arose early after LDLT in adults with a high incidence (35 of 158 patients). Surveillance culture should be checked periodically after LDLT to identify and prevent the transmission of MRSA.

The risk of infection after nasal colonization with Staphylococcus aureus

PURPOSE

Nasal, axillary, or inguinal colonization with Staphylococcus aureus generally precedes invasive infection. Some studies have found that colonization with methicillin-resistant S. aureus (MRSA) poses a greater risk of clinical infection than colonization with methicillin-susceptible S. aureus (MSSA). However, the magnitude of risk is unclear.

METHODS

We undertook a systematic review to provide an overall estimate of the risk of infection following colonization with MRSA compared with colonization by MSSA. Ten observational studies, with a total of 1170 patients, were identified that provided data on both MSSA and MRSA colonization and infection. A random-effects model was used to obtain pooled estimates of the odds ratio and 95% confidence interval.

RESULTS

Overall, colonization by MRSA was associated with a 4-fold increase in the risk of infection (odds ratio 4.08, 95% confidence interval, 2.10-7.44). Studies differed in the choice of patient population, severity of illness, and frequency of sampling to detect colonization.

CONCLUSION

Further research is needed to identify effective methods for sustained eradication of MRSA carriage to reduce the high risk of subsequent infection.

Impact of new methicillin-resistant Staphylococcus aureus carriage postoperatively after living donor liver transplantation

BACKGROUND

Preoperative carriage of methicillin-resistant Staphylococcus aureus (MRSA) is associated with an increased risk of MRSA infection after liver transplantation. It is not known, however, whether new MRSA carriage postoperatively also increases the risk of MRSA infection after liver transplantation.

METHODS

We retrospectively reviewed the data from 242 adult patients who underwent living donor liver transplantation (LDLT) including microbiological and medical records from admission to 3 months after LDLT. Uni and multivariate analyses were performed to identify independent risk factors for postoperative MRSA infection among preoperative noncarriers of MRSA.

RESULTS

Postoperative MRSA infection occurred in 18 of 219 preoperative noncarriers of MRSA by median postoperative day 26. Operation time of at least 16 hours and postoperative colonization with MRSA independently predicted postoperative MRSA infection.

CONCLUSION

Postoperative surveillance cultures should be performed periodically after liver transplantation to identify high-risk candidates for postoperative MRSA infection, even among preoperative noncarriers of MRSA.

Methicillin-resistant Staphylococcus aureus infection after living-donor liver transplantation in adults

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) infection frequently complicates the postoperative course in deceased-donor liver transplantation. The incidence and risk factors of MRSA infection after Living-donor Liver transplantation (LDLT), however, are unclear.

METHODS

We retrospectively reviewed the data from 242 adult patients who underwent LDLT at the University of Tokyo Hospital. The microbiologic and medical records of the patients from admission to 3 months after LDLT were reviewed. Uni- and multivariate analyses were performed to identify the independent risk factors for postoperative MRSA infection.

RESULTS

Postoperative MRSA infection occurred in 25 of 242 patients by median postoperative day 23. Preoperative MRSA colonization, preoperative use of antimicrobials, operation time (> or =16 h), and postoperative apheresis independently predicted postoperative MRSA infection.

CONCLUSION

Surveillance culture should be checked periodically after admission to identify patients at high risk for MRSA infection and to administer appropriate antimicrobials for perioperative infection. Postoperative apheresis, suggesting postoperative liver dysfunction, predisposed patients to MRSA infection.

Successful salvage therapy with tigecycline after linezolid failure in a liver transplant recipient with MRSA pneumonia

Pulmonary infections are a significant cause of morbidity and mortality after liver transplantation. Infections with methicillin-resistant Staphylococcus aureus (MRSA) have increased in the last 10 years. Mortality may exceed 80% in liver transplant recipients who develop MRSA pneumonia. A 57-year-old male following living-donor liver transplantation developed a right-sided MRSA pneumonia 6 weeks after transplantation, which required artificial ventilation for 14 weeks. Initially, pneumonia was treated with linezolid. However, after 12 days under current therapy, the infection spread out to both lungs. At that time. we initiated the treatment with tigecycline. Under this therapy, the patient could be cured from MRSA pneumonia and was extubated. We detected no tigecycline related hepatotoxic effect. In conclusion, this case suggests that tigecycline may be useful in the salvage therapy of pneumonia due to MRSA after linezolid failure.

Impact of an aggressive infection control strategy on endemic Staphylococcus aureus infection in liver transplant recipients

BACKGROUND

Methicillin-resistant Staphylococcus aureus has emerged as a leading pathogen in transplant recipients and has become endemic in many institutions where transplantation is performed. The role of active surveillance programs based on the detection of colonization in the prevention of S. aureus infection in liver transplant recipients has not been defined.

METHODS

A total of 47 consecutive patients who underwent liver transplantation during 1996-1999 were compared with 97 patients who received a liver transplant during 2000-2004 after implementation of an intensive intervention program that included use of surveillance cultures to detect nasal and rectal colonization, use of cohorting and contact isolation precautions, and decolonization with intranasal mupirocin therapy.

RESULTS

The rate of new acquisition of S. aureus colonization of nares after transplantation decreased from 45.6% (21 of 46 patients) during the preintervention period to 9.9% (9 of 91 patients) during the postintervention period (P<.001). An increased length of hospital stay (odds ratio, 1.03; 95% confidence interval, 1.01-1.05; P<.002) was associated with new carriage acquisition, and transplantation during the postintervention period (odds ratio, 0.21; 95% confidence interval, 0.08-0.51; P<.001) was independently protective against new carriage. The rate of infection due to S. aureus decreased from 40.4% (19 of 47 patients) during the preintervention period to 4.1% (4 of 97 patients) during the postintervention period (P<.001), and the rate of bacteremia decreased from 25.5% (12 of 47 patients) to 4.1% (4 of 97 patients), respectively (P<.001). Overall, S. aureus infections occurred more frequently among patients with new carriage than among patients who were carriers at the time of transplantation (P<.001) or patients who were noncarriers (P<.001).

CONCLUSIONS

Use of active surveillance cultures to detect colonization and implementation of targeted infection control interventions proved to be effective in curtailing new acquisition of S. aureus colonization and in decreasing the rate of S. aureus infection that was endemic in our population of liver transplant recipients.

The role of nasal carriage in Staphylococcus aureus infections

Staphylococcus aureus is a frequent cause of infections in both the community and hospital. Worldwide, the increasing resistance of this pathogen to various antibiotics complicates treatment of S aureus infections. Effective measures to prevent S aureus infections are therefore urgently needed. It has been shown that nasal carriers of S aureus have an increased risk of acquiring an infection with this pathogen. The nose is the main ecological niche where S aureus resides in human beings, but the determinants of the carrier state are incompletely understood. Eradication of S aureus from nasal carriers prevents infection in specific patient categories-eg, haemodialysis and general surgery patients. However, recent randomised clinical trials in orthopaedic and non-surgical patients failed to show the efficacy of eliminating S aureus from the nose to prevent subsequent infection. Thus we must elucidate the mechanisms behind S aureus nasal carriage and infection to be able to develop new preventive strategies. We present an overview of the current knowledge of the determinants (both human and bacterial) and risks of S aureus nasal carriage. Studies on the population dynamics of S aureus are also summarised.

Methicillin-resistant Staphylococcus aureus infection in liver transplantation: a matched controlled study

The purpose of this study was to evaluate the clinical impact of methicillin-resistant Staphylococcus aureus (MRSA) infections on transplant recipients.

METHODS

Liver and kidney recipients with MRSA infections were retrospectively identified and compared to an age, gender, UNOS status, organ transplanted, and transplant date matched (2:1) non-MRSA-infected recipient control group. All MRSA infections were initially treated with vancomycin, and four (33%) liver recipients were converted to linezolid therapy after failing to improve with vancomycin.

RESULTS

The overall MRSA infection incidence was 1.4% (24/1770) with MRSA more common in liver (3.75%; 12/320) than kidney transplants (0.8%; 12/1450) (P < .001). The most common sites of MRSA infection were blood (42%), lung (38%), and abdomen (29%). The MRSA group had a greater percentage of prior antibiotic usage (79% vs 40%; P < .0015). The MRSA group experienced more posttransplant complications (52% vs 19%; P < .011)), and exhibited a trend toward greater length of stay in the intensive care unit (7.8 vs 4.6 days; P = .09), but not overall length of stay. Survival was similar in MRSA and non-MRSA groups (75% vs 88%; P = .17). No significant differences in mortality were noted between liver and kidney recipients infected with MRSA (P = .6).

CONCLUSION

MRSA infection is associated with a higher incidence of posttransplant complications and antibiotic usage in both liver and kidney recipients compared to patients with MRSA infection.

Risk factors for Staphylococcus aureus infection in liver transplant recipients

Staphylococcus aureus is the leading cause of bacterial infection in liver transplant recipients. Preoperative nasal carriage of methicillin-resistant S. aureus (MRSA) is associated with a high risk of infection. We conducted a retrospective cohort study in order to identify independent risk factors for early-onset S. aureus infection after liver transplantation. Patients were screened preoperatively for methicillin-susceptible S. aureus (MSSA) and MRSA nasal carriage. Risk factor analysis was performed by univariate analysis followed by stepwise logistic regression. Of the 323 patients included, 63 (19.5%) patients developed S. aureus infection (36 MRSA, 27 MSSA) within 1 month of surgery. Variables significantly associated with infection in the univariate analysis were MRSA and MSSA nasal carriage, alcoholic cirrhosis, absence of hepatocellular carcinoma, decreased prothrombin ratio, and presence of ascites. In the multivariate analysis, MRSA carriage (odds ratio [OR]: 20.9, P < 0.0001), MSSA carriage (OR: 3.4, P = 0.0004), alcoholic cirrhosis (OR: 2.4, P = 0.01) and decreased prothrombin ratio (OR: 1.2, P = 0.01) were independent predictors of infection. Molecular typing showed that the infecting isolate was identical to the isolate from the nose in most patients. In conclusion, preoperative nasal carriage of MRSA and MSSA is an independent risk factor for S. aureus infection in liver transplant recipients. The infection is most often of endogenous origin. Alcoholic cirrhosis and the severity of liver failure are also associated with a high risk of infection.

Methicillin-resistant Staphylococcus aureus and beyond: what's new in the world of the golden staph?

Methicillin-resistant Staphylococcus aureus (MRSA) continues to plague our hospitals. With the appearance of isolates that are resistant to vancomycin, now, more than ever, we must direct our efforts to controlling its development and spread. New antimicrobials have become available for treatment, but may only be a short-term answer. Our efforts towards control must be directed towards infection control measures such as improved hand hygiene with user-friendly products, such as alcohol-based hand disinfectants. Intranasal mupirocin may have a place in prevention of surgical site infection, although this role has not yet been clearly defined. Other areas where MRSA control may be effected include prudent controlled use of antibiotics, including surgical prophylaxis.

Colonization with methicillin-resistant Staphylococcus aureus after liver transplantation

Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of infection after orthotopic liver transplantation (OLT). Colonization with MRSA is associated with a higher risk of infection. Previous studies have shown a high prevalence of MRSA colonization among OLT candidates. However, the risk of colonization with MRSA after OLT is still unclear. The objective of this study was to estimate the incidence and the factors associated with colonization with MRSA after OLT. This was a prospective cohort study including patients submitted to OLT between the years 2000 and 2002. Surveillance cultures of nasal swab specimens were performed within the 1st 72 hours of hospital admission and, subsequently, on weeks 2, 6, 13, and 26. Patients whose baseline cultures revealed nasal carriage of MRSA were excluded. A total of 60 patients were included in the study. The median follow-up was 72 days. A total of 9 patients (15%) became colonized. In multiple logistic regression analyses, the use of a urinary catheter for > or =5 days (P = .006), postoperative bleeding at the surgical site (P = .009), and preoperative use of fluoroquinolones (P = .08) were associated with a higher risk of colonization. Patients without any of these risk factors did not become colonized. In conclusion, nasal carriage of MRSA is frequently acquired after OLT. Periodic postoperative screening for MRSA carriage should be an integral component in programs designed to reduce nosocomial MRSA transmission in these patients. Further studies are needed to set up and validate a predictive model that could allow targeting postoperative screening to high-risk OLT recipients.

Control of endemic MRSA-what is the evidence? A personal view

Although there is extensive literature on the control of MRSA, when that concerning epidemics is excluded, only a limited amount remains regarding the control of endemic MRSA. Several guidelines have been recently published recommending stringent control measures, which are often suggested based on their success in controlling MRSA outbreaks in hospitals with few MRSA or in containing MRSA cases introduced into a hospital with no MRSA. In these settings, multiple measures are usually introduced with apparently successful results. However, results may not be generalizable to other settings and we do not know the minimum effective measures required for MRSA containment. This paper aims critically to review the literature to determine whether evidence exists for the value of the infection control measures that are widely recommended in the endemic setting. Much of this literature is based on observational studies, with few randomized, controlled trials having been conducted. More well-designed studies are required before many of the principles on which we build infection control programmes can be regarded as evidence based.

Prevalence, molecular epidemiology, and clinical significance of heterogeneous glycopeptide-intermediate Staphylococcus aureus in liver transplant recipients

We investigated the prevalence, molecular epidemiology, and clinical significance of heterogeneous glycopeptide-intermediate Staphylococcus aureus (hGISA) isolates in 48 liver transplant recipients infected or colonized with methicillin-resistant S. aureus over a 5-year period. Strains were screened for hGISA on Mueller-Hinton agar containing 5 mg of teicoplanin per liter. Heterogeneous glycopeptide resistance was confirmed by the E-test method with a dense inoculum and a simplified method of population analysis. hGISA strains were found in 13 (27%) of the 48 patients studied. Eleven of the 13 strains shared a common multiresistant phenotype with homogeneous methicillin resistance and gentamicin resistance, and they were closely related according to the results of pulsed-field gel electrophoresis. Only 2 of the 13 patients infected or colonized with hGISA strains had previously received glycopeptide therapy. Most patients were successfully treated with vancomycin, but one patient who failed to respond to vancomycin subsequently died. These results suggest that the high prevalence of hGISA among our patients was due to the clonal spread of a multiresistant strain.

Carriage of methicillin-resistant Staphylococcus aureus is associated with an increased risk of infection after liver transplantation

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of sepsis in patients with cirrhosis and after liver transplantation. The association between nasal carriage of MRSA and sepsis in these patients is unclear. The goal of this study was to investigate the relationship between MRSA carriage before liver transplantation and subsequent sepsis after transplantation. This was a retrospective study of 374 consecutive adults who underwent orthotopic liver transplantation between 1998 and 2001 and for whom full data were available. Of these, 157 had been screened for MRSA as part of a study assessing the prevalence of MRSA infection. All MRSA carriers were treated with nasal mupirocin and chlorhexidine baths. The records of MRSA carriers and noncarriers were analyzed for Child and Model for End-Stage Liver Disease (MELD) score, posttransplantation MRSA, and other infections and mortality. Of the 157 patients who had an MRSA screen, 35 patients were MRSA nasal carriers. These carriers had significantly greater MELD score (mean, 16.2 compared with 13.1; P =.02) and Child scores (mean, 10 versus 9; P =.001) than noncarriers. The incidence of posttransplantation MRSA infection was significantly higher in MRSA carriers (31% versus 9%; P =.002). The incidence of other posttransplantation infection was not significantly different in the two groups. There was no significant difference in survival between the two groups (1-year patient survival, 74% and 82%, respectively). Patients carrying MRSA are predisposed to an increased risk of sepsis after liver transplantation with a trend to increased mortality. Screening for MRSA should be considered in high-risk patients being assessed for liver transplantation.

The risk of persistent carriage of methicillin-resistant Staphylococcus aureus in hematopoietic stem cell transplantation

The clinical course of hematopoietic stem cell transplantation (HSCT) recipients was retrospectively analyzed to determine whether carriage of methicillin-resistant Staphylococcus aureus (MRSA) is a risk factor for MRSA infection during the neutropenic period. We studied four patients in whom MRSA colonies developed before HSCT. Two patients were previously diagnosed as having MRSA infection and two were carriers of MRSA. We tried to eliminate MRSA before HSCT and succeeded in eradication in two patients. MRSA infection did not develop in one patient who received prophylactic administration of vancomycin (VCM), but MRSA-induced phlegmon developed during neutropenia in one patient who did not receive prophylaxis. Of the other two patients who had been persistently positive for MRSA, MRSA did not develop in one patient who received prophylaxis, but the another patient who did not receive prophylaxis died from MRSA-induced sepsis in the early post-transplant period. We therefore recommend that MRSA be eliminated by prophylactic administration of anti-MRSA drugs such as VCM before HSCT when patients have persistent MRSA.