Urinary Tract Infections Caused by K. pneumoniae in Kidney Transplant Recipients – Epidemiology, Virulence and Antibiotic Resistance

Clinical and Microbiological Characteristics of Carbapenem-Resistant Klebsiella pneumoniae Associated Recurrent Urinary Tract Infections

Background

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a major pathogen responsible for urinary tract infections (UTIs). However, its role and characteristics in recurrent urinary tract infections (rUTIs) remain poorly understood. Investigating its features in rUTIs may provide insights into effective prevention strategies.

Methods

We analyzed a cohort of patients with rUTIs caused by Klebsiella pneumoniae from April 2020 to April 2024. Antibiotic susceptibility of the isolates was evaluated. Biofilm Formation Assay and Galleria mellonella infection models were employed to assess the virulence of the strains. Polymerase Chain Reaction (PCR) and whole-genome sequencing (WGS) were utilized to determine multilocus sequence typing (MLST) and capsular serotyping, as well as to identify resistance genes, virulence genes, and plasmid replicons. Phylogenetic relationships among the isolates were also established.

Results

A total of 41 patients with rUTIs were included, with 56.1% caused by CRKP. 97.01% of CRKP carry the blaKPC-2 gene. Compared to patients infected with carbapenem-susceptible Klebsiella pneumoniae (CSKP), those infected with CRKP had a higher prevalence of underlying diseases and complications. Both groups of strains exhibited a high degree of antibiotic resistance. CRKP strains demonstrated enhanced biofilm formation capacity and greater lethality in Galleria mellonella infection models. The predominant phenotype of the CRKP strain was ST11 KL64, whereas the CSKP strain showed multiple phenotypes in different patients. Sequencing analyses revealed that both groups of strains carried a wide range of virulence genes, resistance genes, and plasmid replicons. Among the cases of rUTIs, 31 were identified as relapses caused by the same strain, with no significant differences between the initial and final infection strains.

Conclusion

This study demonstrates that patients with rUTIs caused by CRKP present significant complexity in terms of clinical features, strain resistance and virulence properties. When managing UTIs caused by CRKP, special care needs to be taken to manage recurrent infections.

Case Report: Management of recurrent UTI with tigecycline in a kidney transplant recipient

This case report describes a 37-year-old man who underwent renal transplantation and subsequently developed complicated recurrent urinary tract infections (UTIs) caused by multidrug-resistant (MDR) Klebsiella pneumoniae. Despite initial treatment with fosfomycin and meropenem, the patient experienced persistent UTIs, leading to multiple hospitalizations. The management of these recurrent infections eventually required the use of tigecycline. Although tigecycline is not typically considered a urinary antibiotic owing to its limited urinary excretion, it was successfully employed in this case to manage the recurrent infections. The patient was treated with tigecycline for several episodes of UTI, which provided a crucial therapeutic option in the context of antibiotic resistance. This case underscores the challenges of managing recurrent MDR UTIs in immunocompromised patients and highlights tigecycline as an effective treatment strategy when standard therapies fail.

Case Report: Management of a case of multidrug-resistant Klebsiella pneumoniae infection in a second-kidney transplant patient

This case report on recurrent urinary tract infections (UTIs) caused by multidrug-resistant (MDR) Klebsiella pneumoniae in a post-renal transplant patient underscores the significant clinical challenge of managing MDR infections in immunocompromised individuals, particularly in the context of renal transplantation. The patient was treated with an extended infusion of meropenem, which offers prolonged drug exposure and enhances bactericidal activity against MDR pathogens. This approach is critical in overcoming the resistance mechanisms inherent to Klebsiella pneumoniae, thereby improving the likelihood of therapeutic success. The findings presented here highlight the potential efficacy of extended meropenem infusion in treating MDR infections, providing a valuable therapeutic option for clinicians facing similar cases. This report contributes to the growing evidence supporting advanced antibiotic administration techniques in managing complicated urinary tract infections in transplant in resource limited countries.

Review of Association between Urinary Tract Infections and Immunosuppressive Drugs after Heart Transplantation

Management of infections in heart transplant recipients is complex and crucial. In this population, there is a need for a better understanding of immunosuppressive trough levels (C0), infectious complications, and urinary tract infections (UTIs). The purpose of this review was to understand the association between immunosuppressive trough levels and UTIs after heart transplantation. A review of scientific literature (n= 100) was conducted based on the topic of interest by searching PUBMED.Gov (https://pubmed.ncbi.nlm.nih.gov/), Web of Science, and Scopus. The analysis of bacterial pulmonary infection required the occurrence of new or deteriorating pulmonary infiltrates and the development of organisms in cultures of sputum specimens. The diagnosis of UTIs was based on the result of related signs, pyuria, and a positive urine culture. The incidence of UTIs was reported as 0.07 episodes/1000 regarding heart transplantation days. An eightfold increase in the rate of rejection was noted in heart transplant recipients with higher variability in tacrolimus C0. There are associations between C0 of immunosuppressive drugs and clinical presentation of infection complications. Recipients with a low metabolism of immunosuppressive drugs are more susceptible to infectious complications. Attention to the biology of herpes viruses, Escherichia coli, Enterococcus spp., Pseudomonas aeruginosa, and Staphylococcus saprophyticus after heart transplantation are important, in which some of them are the most common pathogens responsible for UTIs. Pneumocystis and cytomegalovirus affect all transplant recipients. Pneumonia due to bacterial, viral, protozoa, and fungal infections, in addition to UTIs, are more specific reported types of infections in heart transplant recipients. Bacterial infections produced by extensively drug-resistant Enterobacteriaceae, vancomycin-resistant enterococci, and non-fermenting gramnegative bacteria were reported to increase after transplantation.

A combined therapy of meropenem-ZnO nanoparticles efficiently eliminates carbapenem-resistant Klebsiella pneumoniae biofilms, with reduced nephrotoxicity (in vitro)

In response to the World Health Organization's research agenda of antimicrobial resistance in human health, this study appraised the antibacterial and antibiofilm synergistic activity of meropenem and ZnO nanoparticles (ZnO-NPs) combination against carbapenem-resistant Klebsiella pneumoniae (CRKP). The minimum inhibitory concentration (MIC) of meropenem in combination was found to be ~1/12 of its MIC alone. The results of microtiter dilution assay showed that the combination was more efficient in reducing the biofilm biomass than meropenem alone or ZnO-NPs alone. The scanning-electron-microscopy micrographs elucidated that the combination of meropenem with ZnO-NPs has significantly enhanced its competence in eradicating the preformed biofilms of CRKP strains. In addition, the relative gene expression results showed that the combination compared to the meropenem alone and ZnO-NPs alone eloquently down-regulated the expression of biofilm genes (mrkA, fimA, and ecpA). Besides, the MTT-assay demonstrated that the combination has limited cytotoxicity against Vero-cells (in vitro). Overall, this study represents an efficient safe enhancement of meropenem to tackle the growing health threat of CRKP and carbapenem-resistant Enterobacterals prevalence.

Urinary Tract Infections in Kidney Transplant Patients: An Open Challenge-Update on Epidemiology, Risk Factors and Management

Urinary tract infections are one of the main complications in kidney transplant patients, with a significant impact on graft function and survival. In fact, it is estimated that up to 74% of kidney transplant patients experience at least one episode of UTIs in the first year after transplantation, with an increased risk of graft loss and an increased risk of mortality. Several risk factors have been identified, such as female gender, old age, diabetes mellitus, immunosuppression, pre-transplant UTIs, urinary tract abnormalities, and prolonged dialysis. The worsening burden of antimicrobial resistance is also in itself a risk factor and a major complication in evolution and management. The management of prophylaxis, asymptomatic bacteriuria, and UTIs is still an open challenge, with some points to be clarified. Faced with such scenarios, our review aimed to evaluate the current epidemiology, examine the risk factors, and consider all the possibilities and methods of management, giving a current view and evaluation of the topic.

Assessment of Posttransplant Bacteremia Caused by Extended-Spectrum Beta-Lactamase-Producing Gram-Negative Bacteria Among Kidney Transplant Recipients

BACKGROUND

Extended-spectrum beta-lactamase-producing gram-negative rods (ESBL-GNR) are a rising cause of bacteremia in kidney transplant recipients (KT). The study purpose was to examine patient mortality, allograft survival, estimated glomerular filtration rate (eGFR) at the end of 1 year, and readmission rates while looking at treatment strategies among KTs with ESBL-GNR and non-ESBL-GNR bacteremia at our institution.

METHODS

This study was a retrospective, cohort analysis of KTs with gram-negative bacteremia from January 1, 2020, to December 31, 2021. The primary outcome of the study was mortality. Patient outcomes were assessed for 365 days after positive blood cultures.

RESULTS

The study included 63 patients. Of these, 18 (29%) patients had bacteremia caused by an ESBL-GNR and 45 (71%) patients had bacteremia caused by a non-ESBL-GNR. Patient survival at 90 days was 94% in the ESBL-GNR group and 96% in the non-ESBL-GNR group. Ciprofloxacin was the most common antimicrobial therapy at discharge (68.9%) in the non-ESBL-GNR group whereas ertapenem was the most common in the ESBL-GNR group (44.5%). Median eGFR at discharge was 41 mL/min/1.73 m2 in the ESBL-GNR group and 48 mL/min/1.73 m2 in the non-ESBL-GNR group. Ninety-day readmission occurred in 9 (50%) ESBL-GNR patients and 14 (32%) non-ESBL-GNR patients. None of the above comparisons are statistically significant (p > 0.05). Eleven (61%) ESBL-GNR and 2 (4%) non-ESBL-GNR patients used outpatient parenteral antimicrobial therapy (p < 0.001).

CONCLUSIONS

Among KTs with ESBL-GNR bacteremia, no significant difference was detected in mortality or allograft function compared to non-ESBL-GNR bacteremia.

Hybrid Sequencing-Based Genomic Analysis of Klebsiella pneumoniae from Urinary Tract Infections Among Inpatients at a Tertiary Hospital in Beijing

Background

Urinary tract infection (UTI) associated with Klebsiella pneumoniae poses a serious threat for inpatients. This study aimed to describe the genomic characteristics of K. pneumoniae causing UTI in a tertiary-care hospital in Beijing, China.

Methods

A total of 20 K. pneumoniae strains collected from 2020 to 2021 were performed whole-genome sequencing. The Antibiotic susceptibility of 19 common antimicrobial agents was tested against all strains. The multi-locus sequence types (MLSTs) and serotypes were determined from the WGS data. De novo assemblies were used to identify resistance and virulence genes. The presence and characteristics of the plasmids were detected using hybrid assembly of long and short-read data.

Results

These K. pneumoniae strains were clustered into nine sequence types (STs) and twelve K-serotypes. All the carbapenem-resistant K. pneumoniae (CRKP) strains acquired carbapenemase blaKPC-2 (n=7). Two CRKP strains exhibited increased resistance to Polymyxin B with MIC ≥ 4 mg/L due to insertion of an IS5-like sequence in the mgrB gene, and they were also involved in a transmission event in Intensive Care Unit. Long-read assemblies identified many plasmids co-carrying multiple replicons. Acquisition of a new IncM2_1 type blaCTX-M-3 positive plasmid was observed after transfer from ICU to neurovascular surgery by comparing the two strains collected from the same patient.

Conclusion

K. pneumoniae is a significant pathogen responsible for urinary tract infections. The ST11-KL47 strain, prevalent at our hospital, exhibits a combination of high drug resistance and hypervirulence. It is imperative to enhance ongoing genomic surveillance of urinary tract infection-causing pathogens.

Clinical Characteristics of Uncomplicated Acute Pyelonephritis Caused by Escherichia coli and Klebsiella pneumoniae

INTRODUCTION

This study compared the clinical characteristics and antimicrobial susceptibility of uncomplicated acute pyelonephritis (APN) caused by Escherichia coli and Klebsiella pneumoniae.

METHODS

We retrospectively reviewed the medical records of patients with uncomplicated APNs caused by E. coli and K. pneumoniae admitted to Keimyung University Dongsan Hospital between February 2014 and December 2021.

RESULTS

We enrolled 497 patients (372 with E. coli infection, 125 with K. pneumoniae infection). Male, healthcare-associated infection, solid tumors, liver cirrhosis, chronic renal disease, solid organ transplantation, and antibiotic usage within the last 3 months were more strongly associated with K. pneumoniae uncomplicated APNs than with E. coli. Bacteremia and fever occurred more frequently in E. coli uncomplicated APNs. Antimicrobial resistance rates to piperacillin/tazobactam and carbapenem were higher in K. pneumoniae. Antimicrobial resistance rates to aztreonam and ciprofloxacin were lower in K. pneumoniae. Thirty-day mortality was more observed in K. pneumoniae group in univariate analysis, but this difference was not observed after adjustment. Male sex, ultimately fatal disease in McCabe, and prior antibiotic use within 3 months were more associated with K. pneumoniae.

CONCLUSIONS

Male, underlying diseases, and prior antibiotic use was more associated with K. pneumoniae. Further study will be needed that microbiome of each situation and the related with the distribution of the strains.

Comprehensive Review of Urinary Tract Infections in Renal Transplant Recipients: Clinical Insights and Management Strategies

Urinary tract infections (UTIs) pose a significant challenge in the care of renal transplant recipients. This comprehensive review explores this population's multifaceted landscape of UTIs, emphasizing the importance of early diagnosis and tailored management strategies. Renal transplant recipients face an elevated risk of UTIs due to immunosuppression, altered urinary tract anatomy, and complex comorbidities. Complications of UTIs can lead to graft dysfunction and systemic illness, underscoring the need for effective management. The emergence of multidrug-resistant uropathogens adds complexity to treatment, highlighting the importance of targeted antibiotic therapy. Antibiotics are the most commonly prescribed drugs for UTIs, with nitrofurantoin, fosfomycin, amoxicillin, and amoxicillin-clavulanate potassium being some of the commonly used antibiotics. However, the emergence of multidrug-resistant uropathogens has led to the exploration of alternative treatments, such as bacteriophage therapy, as a potential alternative against multidrug-resistant uropathogenic bacteria. Analgesics such as phenazopyridine can be prescribed to relieve discomfort associated with UTIs. Estrogen therapy has also been suggested as a potential treatment option for UTIs, particularly in postmenopausal women. Trimethoprim-sulfamethoxazole or trimethoprim is recommended as first-line therapy for uncomplicated UTIs. The choice of drug and therapy for UTIs depends on the severity of the infection, the causative organism, and the presence of antibiotic resistance. Preventive measures encompass pre-transplant evaluation, perioperative strategies, post-transplant follow-up, and vaccination. A multidisciplinary approach involving transplant specialists, infectious disease experts, pharmacists, and patient engagement is vital for successful care. The future of UTI management lies in ongoing research, exploring personalized medicine, novel therapies, and innovative prevention strategies. By implementing these strategies and advancing research, healthcare providers can improve graft and patient survival, enhancing the quality of care for renal transplant recipients.

Asymptomatic Bacteriuria in Kidney Transplant Recipients-A Narrative Review

Urinary tract infections (UTIs) are the most prevalent complications in kidney transplant (KTx) recipients. The most frequent finding in this group of patients is asymptomatic bacteriuria (ASB). Here, we provide an overview of the available evidence regarding ASB in KTx recipients, including its etiopathology, clinical impact and management. There is a growing body of evidence from clinical trials that screening for and treating ASB is not beneficial in most KTx recipients. However, there are insufficient data to recommend or discourage the use of a "screen-and-treat strategy" for ASB during the first 1-2 months post-transplant or in the case of an indwelling urinary catheter. Despite its frequency, ASB after KTx is still an understudied phenomenon.

Epidemiology and Risk Factors of UTIs in Children-A Single-Center Observation

Urinary tract infections (UTIs) are one of childhood’s most common bacterial infections. The study aimed to determine the clinical symptoms, laboratory tests, risk factors, and etiology of different UTIs in children admitted to pediatric hospitals for three years. Methods: Patients with positive urine cultures diagnosed with acute pyelonephritis (APN) or cystitis (CYS) were analyzed for clinical symptoms, laboratory tests, risk factors, and etiology, depending on their age and sex. Results: We studied 948 children with UTIs (531 girls and 417 boys), with a median age of 12 (IQR 5−48 months). A total of 789 children had clinical symptoms; the main symptom was fever (63.4% of patients). Specific symptoms of UTIs were presented only in 16.3% of patients. Children with APN had shown significantly more frequent loss of appetite, vomiting, lethargy, seizures, and less frequent dysuria and haematuria than children with CYS. We found significantly higher median WBC, CRP, and leukocyturia in children with APN than with CYS. The risk factors of UTIs were presented in 46.6% of patients, of which 35.6% were children with APN and 61.7% with CYS. The main risk factor was CAKUT, more frequently diagnosed in children with CYS than APN, mainly in children <2 years. The most commonly isolated bacteria were Escherichia coli (74%). There was a higher percentage of urine samples with E. coli in girls than in boys. Other bacteria found were Klebsiella species, Pseudomonas aeruginosa, Proteus mirabilis, and Enterococcus species. Conclusions: Patients with APN were younger and had higher inflammatory markers. Often, fever is the only symptom of UTI in children, and other clinical signs are usually non-specific. The most common UTI etiology is E. coli, regardless of the clinical presentation and risk factors.

Comparative Analysis of Complicated Urinary Tract Infections Caused by Extensively Drug-Resistant Pseudomonas aeruginosa and Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae

The objective was to compare clinical characteristics, outcomes, and economic differences in complicated urinary tract infections (cUTI) caused by extensively drug-resistant Pseudomonas aeruginosa (XDR P. aeruginosa) and extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-K. pneumoniae). A retrospective study was conducted at a tertiary care hospital. Patients with XDR P. aeruginosa and ESBL-K. pneumoniae cUTIs were compared. The primary outcome was clinical failure at day 7 and at the end of treatment (EOT). Secondary outcomes: 30- and 90-day mortality, microbiological eradication, and economic cost. Two-hundred and one episodes were included, of which 24.8% were bloodstream infections. Patients with XDR P. aeruginosa cUTI more frequently received inappropriate empirical therapy (p < 0.001). Nephrotoxicity due to antibiotics was only observed in the XDR P. aeruginosa group (26.7%). ESBL-K. pneumoniae cUTI was associated with worse eradication rates, higher recurrence, and higher infection-related readmission. In multivariate analysis, XDR P. aeruginosa was independently associated with clinical failure on day 7 of treatment (OR 4.34, 95% CI 1.71−11.04) but not at EOT, or with mortality. Regarding hospital resource consumption, no significant differences were observed between groups. XDR P. aeruginosa cUTI was associated with worse early clinical cures and more antibiotic side effects than ESBL-K. pneumoniae infections. However, no differences in mortality or in hospitalization costs were observed.