Infections after orthotopic liver transplantation in the intensive care unit

Role of a Real-Time TDM-Based Expert Clinical Pharmacological Advice Program in Optimizing the Early Pharmacokinetic/Pharmacodynamic Target Attainment of Continuous Infusion Beta-Lactams among Orthotopic Liver Transplant Recipients with Documented or Suspected Gram-Negative Infections

(1) Objectives: To describe the attainment of optimal pharmacokinetic/pharmacodynamic (PK/PD) targets in orthotopic liver transplant (OLT) recipients treated with continuous infusion (CI) beta-lactams optimized using a real-time therapeutic drug monitoring (TDM)-guided expert clinical pharmacological advice (ECPA) program during the early post-surgical period. (2) Methods: OLT recipients admitted to the post-transplant intensive care unit over the period of July 2021-September 2023, receiving empirical or targeted therapy with CI meropenem, piperacillin-tazobactam, meropenem-vaborbactam, or ceftazidime-avibactam optimized using a real-time TDM-guided ECPA program, were retrospectively retrieved. Steady-state beta-lactam (BL) and/or beta-lactamase inhibitor (BLI) plasma concentrations (Css) were measured, and the Css/MIC ratio was selected as the best PK/PD target for beta-lactam efficacy. The PK/PD target of meropenem was defined as being optimal when attaining a fCss/MIC ratio > 4. The joint PK/PD target of the BL/BLI combinations (namely piperacillin-tazobactam, ceftazidime-avibactam, and meropenem-vaborbactam) was defined as being optimal when the fCss/MIC ratio > 4 of the BL and the fCss/target concentration (CT) ratio > 1 of tazobactam or avibactam, or the fAUC/CT ratio > 24 of vaborbactam were simultaneously attained. Multivariate logistic regression analysis was performed for testing potential variables that were associated with a failure in attaining early (i.e., at first TDM assessment) optimal PK/PD targets. (3) Results: Overall, 77 critically ill OLT recipients (median age, 57 years; male, 63.6%; median MELD score at transplantation, 17 points) receiving a total of 100 beta-lactam treatment courses, were included. Beta-lactam therapy was targeted in 43% of cases. Beta-lactam dosing adjustments were provided in 76 out of 100 first TDM assessments (76.0%; 69.0% decreases and 7.0% increases), and overall, in 134 out of 245 total ECPAs (54.7%). Optimal PK/PD target was attained early in 88% of treatment courses, and throughout beta-lactam therapy in 89% of cases. Augmented renal clearance (ARC; OR 7.64; 95%CI 1.32-44.13) and MIC values above the EUCAST clinical breakpoint (OR 91.55; 95%CI 7.12-1177.12) emerged as independent predictors of failure in attaining early optimal beta-lactam PK/PD targets. (4) Conclusion: A real-time TDM-guided ECPA program allowed for the attainment of optimal beta-lactam PK/PD targets in approximately 90% of critically ill OLT recipients treated with CI beta-lactams during the early post-transplant period. OLT recipients having ARC or being affected by pathogens with MIC values above the EUCAST clinical breakpoint were at high risk for failure in attaining early optimal beta-lactam PK/PD targets. Larger prospective studies are warranted for confirming our findings.

Effect of Blood Product Resuscitation on the Pharmacokinetics of Ampicillin-Sulbactam during Orthotopic Liver Transplantation

Background: Ampicillin-sulbactam is a piperacillin-tazobactam-sparing alternative antibiotic administered as surgical prophylaxis during orthotopic liver transplant (OLT), but limited data are available describing its pharmacokinetics and impact of blood product resuscitation. The purpose of this study was to determine the intra-operative pharmacokinetics of ampicillin-sulbactam in patients during OLT and evaluate the effects of blood resuscitation on exposure. Patients and Methods: This was a pharmacokinetic study in 10 OLT patients receiving ampicillin-sulbactam surgical prophylaxis. A 5,000-patient Monte Carlo simulation was conducted to identify optimal ampicillin-sulbactam regimens. Linear regression assessed association between blood product administration and ampicillin exposures. Results: Ampicillin and sulbactam concentrations best fitted two-compartment models. Mean ampicillin pharmacokinetic parameters were central compartment volume (V_c): 6.9 ± 2.0 L, clearance (CL): 26.6 ± 18.4 L/h, and inter-compartmental rate constants (k₁₂ and k₂₁): 4.8 ± 2.6 and 2.3 ± 1.4 h^-1. Sulbactam pharmacokinetic parameters were V_c: 8.1 ± 2.7 L, CL: 26.1 ± 7.4 L/h, k₁₂ and k₂₁: 4.9 ± 1.0 and 2.8 ± 1.1 h^-1. Participants received between 500 and 23,642 mL of total blood product. No statistical relations were observed between blood product administration and exposures (R² 0.00-0.26). Ampicillin-sulbactam 2/1 g every two hours and 2/1 g bolus followed by 6/3 g continuous infusion provided acceptable probability of target attainment up to minimum inhibitory concentrations (MICs) of 16 and 32 mcg/mL, respectively. Conclusions: High and frequent ampicillin-sulbactam doses are required to maintain 100% fT > MIC at relevant MICs during OLT and no impact of blood product resuscitation was observed on ampicillin exposure. These are the first data available to guide ampicillin-sulbactam dosing in patients undergoing OLT.

Evaluation of clinical characteristics and outcomes of postoperative ınfections in living liver donors

AIM

To analyze developing infections after living donor hepatectomy (LDH) in living liver donors (LLDs).

METHODS

Demographic and clinical characteristics of 1106 LLDs were retrospectively analyzed in terms of whether postoperative infection development. Therefore, LLDs were divided into two groups: with (n = 190) and without (n = 916) antimicrobial agent use.

RESULTS

The median age was 29.5 (min-max: 18-55). A total of 257 (23.2%) infection attacks (min-max: 1-8) was developed in 190 (17.2%) LLDs. The patients with the infection that were longer intensive care unit (ICU) and hospital stays, higher hospital admissions, emergency transplantation, invasive procedures for ERCP, PTC biloma, and abscess drainage, and the presence of relaparatomies and transcystic catheters. Infection attacks are derived from a 58.3% hepatobiliary system, 13.2% urinary system, 6.6% surgical site, and 5.8% respiratory system. The most common onset symptoms were fever, abdominal pain, nausea, and vomiting. A total of 125 positive results was detected from 77 patients with culture positivity. The most detected microorganisms from the cultures taken are Extended-Spectrum β-lactamases (ESBL) producing Klebsiella pneumonia (16.8%) and Escherichia coli (16%), Methicillin-Resistant Staphylococcus aureus [(MRSA) (9.6%)], Methicillin-susceptible S aureus [(MSSA) (9.6%)], and Pseudomonas aeruginosa (8.8%), respectively. The average number of ICU hospitalization days was 3 ± 2 (min 1-max 30, IQR:1) and hospitalization days was 14 ± 12 (min 3-max 138, IQR: 8). All infection attacks were successfully treated. No patients died because of infection or another surgical complication.

CONCLUSION

Infections commonly observed infected biloma, cholangitis, and abscess arising from the biliary system and other nosocomial infections are the feared complications in LLDs. These infections should be managed multidisciplinary without delay and carefully.

Perioperative intensive glycemic control for liver transplant recipients to prevent surgical site infection: A systematic review and meta-analysis

BACKGROUND

Surgical Site Infections (SSIs) are common among liver transplant recipients and result in adverse patient outcomes. Standard glycemic control is effective in reducing SSIs. Some studies suggest intensive glycemic control reduces the risk of SSI further.

METHODS

For this systematic review, were searched for studies comparing perioperative intensive and standard glycemic control in liver transplant recipients. Clinical trials registries and reference lists of included studies were also searched. No date or language restrictions were applied. Randomized controlled trials (RCTs) were assessed using Cochrane risk of bias tool and GRADE method. Cohort studies were assessed using the Newcastle-Ottawa Scale.

RESULTS

Two RCTs and three cohort studies met the inclusion criteria. Low-quality evidence from the two RCTs in a meta-analysis with 264 recipients found it was uncertain whether the risk of SSI was reduced by having intensive glycemic control (Risk Ratio [RR] 1.52, 95% CI 0.66-3.51). However, there was an increased risk of hypoglycemia among recipients having intensive glycemic control (RR 2.34, 95% CI 1.40-3.92) n = 264. Meta-analyses found it uncertain whether secondary outcomes, allograft rejection and death, were reduced among recipients having intensive glycemic control; (RR 0.85, 95% CI 0.48-1.50) and (RR 0.92, 95% CI 0.44-1.95), respectively. The two cohort studies were poor quality and presented conflicting outcomes on the effects of intensive blood glucose control on SSI.

CONCLUSION

There is insufficient evidence to recommend the use of intensive glycemic control among liver transplant recipients to reduce SSIs.

A Retrospective Cohort Study of Risk Factors for Surgical Site Infection Following Liver Transplantation

Background:

Surgical site infection is an important complication in the postoperative period among liver transplant recipients. However, little is known about the risk factors in this patient group. Therefore, the objective of this study was to analyze the incidence and risk factors for surgical site infections among adult liver transplant recipients.

Methods:

Medical records of adult liver transplant recipients from January 1, 2009, to December 31, 2015, were analyzed in this retrospective cohort study.

Results:

We enrolled 156 recipients’ medical records. Forty-two (26.9%) cases of surgical site infections were identified. The main isolated microorganisms were methicillin-resistant Staphylococcus species, extended spectrum β-lactamase-producing Klebsiella species, carbapenem-resistant Pseudomonas aeruginosa, carbapenem-resistant Acinetobacter baumannii, and vancomycin-susceptible Enterococcus faecalis. We found that long operative times (≥487 minutes) and differences in body mass index between donor and recipient (≥1.3 kg/m2) increased the risk for surgical site infections by approximately 5 times (odds ratio [OR], 5.5; 95% confidence interval [CI], 2.5-11.8), and capillary glycemia ≥175 mg/dL in the first 96 postoperative hours increased the risk by approximately 3 times (OR, 2.97; 95% CI, 1.43-6.17).

Conclusions:

There was a high incidence of surgical site infections among the studied population and that some risk factors identified differ from those reported in the scientific literature.

INFECÇÕES RELACIONADAS À ASSISTÊNCIA À SAÚDE E FATORES ASSOCIADOS NO PÓS-OPERATÓRIO DE TRANSPLANTE HEPÁTICO

RESUMO Objetivo: identificar a incidência das infecções relacionadas à assistência à saúde e seus fatores associados, durante o primeiro mês do pós-operatório de pacientes adultos submetidos ao transplante hepático em um hospital público de Fortaleza. Método: estudo retrospectivo, descritivo com abordagem quantitativa, realizado com 53 receptores de fígado no primeiro semestre do ano de 2015. Os dados foram coletados através dos prontuários, fichas ambulatoriais e de notificação de infecções. Resultados: dos pacientes avaliados, 15 (28,3%) apresentaram infecção durante o primeiro mês, em que o mais prevalente foi a sepse clínica (n=6; 37,4%), seguida de infecção do trato respiratório (n=3; 18,8%), trato urinário (n=3;18,8%), sítio cirúrgico (n=3; 18,8%) e por último, infecção de corrente sanguínea (n=1; 6,2%). Os que apresentaram associação estatística em relação a não ocorrência de infecções foram o grupo dos pacientes casados e a indicação de cirrose por hepatite C. A média dos dias de internação no pós-operatório, o uso do imunossupressor micofenolato de mofetil e a média do uso de alguns dispositivos invasivos, foram identificados como os fatores associados à ocorrência de infecções, sendo estatisticamente significativos para p=<0,05. Conclusão: a identificação da incidência das infecções relacionadas à assistência à saúde e seus fatores associados em pacientes submetidos ao transplante hepático, poderá subsidiar o direcionamento das ações de saúde, com a finalidade de diminuir a morbimortalidade associada às infecções e otimizando a recuperação desses pacientes.

Predictors of postoperative infectious complications in liver transplant recipients: experience of 185 consecutive cases

BACKGROUND/AIMS

Infections following liver transplant (LT) remain a major cause of mortality. This study was conducted to evaluate risk factors for infection and to review clinical characteristics.

METHODS

Medical records of patients who underwent LT from 2010 to 2014 were retrospectively analyzed. Binary logistic regression analysis was used to investigate risk factors of infection. Kaplan-Meier analysis was used to predict prognosis of infected and non-infected groups.

RESULTS

Of 185 recipients, 89 patients experienced infectious complications. The median follow-up period was 911 days (range, 9 to 2,031). The infected group had higher 1-year mortality (n = 22 [24.7%] vs. n = 8, [8.3%], p = 0.002), and longer postoperative admission days (mean: 53.7 ± 35.8 days vs. 28.3 ± 13.0 days, p &lt; 0.001), compared to the non-infected group. High preoperative Model for End-Stage Liver Disease (MELD) score (odds ratio [OR], 1.057; 95% confidence interval [CI], 1.010 to 1.105; p = 0.016), deceased-donor type (OR, 5.475; 95% CI, 2.442 to 12.279; p &lt; 0.001), and acute rejection (OR, 3.042; 95% CI, 1.241 to 7.454; p = 0.015) were independent risk factors associated with infection. Intra-abdominal infection (n = 35, 20.8%) was the major infectious complication. Among identified bacteria, Enterococcus species (28.4%) were major pathogens, followed by Escherichia coli and Klebsiella species.

CONCLUSIONS

High preoperative MELD score, deceased-donor type, and acute rejection were risk factors associated with infection. To prevent infections following surgery, it is important to determine the appropriate time of operation before the recipient has a high MELD score.

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.

Ventilator associated pneumonia following liver transplantation: Etiology, risk factors and outcome

AIM: To determine the incidence, etiology, risk factors and outcome of ventilator-associated pneumonia (VAP) in patients undergoing orthotopic liver transplantation (OLT).

METHODS: This retrospective study considered 242 patients undergoing deceased donor OLT. VAP was diagnosed according to clinical and microbiological criteria.

RESULTS: VAP occurred in 18 (7.4%) patients, with an incidence of 10 per 1000 d of mechanical ventilation (MV). Isolated bacterial etiologic agents were mainly Enterobacteriaceae (79%). Univariate logistic analysis showed that model for end-stage liver disease (MELD) score, pre-operative hospitalization, treatment with terlipressin, Child-Turcotte-Pugh score, days of MV and red cell transfusion were risk factors for VAP. Multivariate analysis, considering significant risk factors in univariate analysis, demonstrated that pneumonia was strongly associated with terlipressin usage, pre-operative hospitalization, days of MV and red cell transfusion. Mortality rate was 22% in the VAP group vs 4% in the group without VAP.

CONCLUSION: Our data suggest that VAP is an important cause of nosocomial infection during postoperative period in OLT patients. MELD score was a significant risk factor in univariate analysis. Multiple transfusions, treatment with terlipressin, preoperative hospitalization rather than called to the hospital while at home and days of MV constitute important risk factors for VAP development.

DCD liver transplant infection: experience from a single centre in China

AIM

The purpose of our study was to evaluate the incidence, timing, location and risk factors for bacterial and fungal infections after donation after cardiac death (DCD) liver transplant and clearly delineate any relationship between infection and survival in DCD liver transplant recipients.

METHODS

We retrospectively reviewed 257 consecutive patients undergoing DCD liver transplant between October 2010 and May 2015 at our centre.

RESULTS

A total of 133 patients (51.8%) developed at least one bacterial or fungal infection episode. The predominant infection site was the respiratory tract, followed by the blood stream. Most of the infections occurred within the first week after liver transplant (61.9%). A recipient respiratory support time greater than 7 days (p = 0.041), post-transplant hospital time greater than 24 days (p = 0.002) and renal failure after DCD liver transplant (p = 0.039) were independent predictors of bacterial and fungal infection. The area under the receiver operating characteristic (ROC) curve (AUC) of the transplant infection risk assessment model was 0.788. The 1- and 3-year survival rates for recipients without infection were significantly increased compared with recipients with infection (96.1% and 89.0% vs. 81.5% and 75.9%, p = 0.007).

CONCLUSION

This is the first study that offers detailed data revealing the timing and incidence of bacterial and fungal infection among adult DCD liver transplant recipients. Bacterial and fungal infection occurs at a high rate during the first week after DCD liver transplant, especially in patients with prolonged respiratory support time and renal failure, and infection is related to increased hospital stay.