Oral vs Intravenous Antibiotics for Patients With Klebsiella pneumoniae Liver Abscess: A Randomized, Controlled Noninferiority Study

Improving antimicrobial treatment in terms of antimicrobial stewardship and health costs by an OPAT service

PURPOSE

Outpatient parenteral antimicrobial therapy (OPAT) is a standard for antimicrobial therapy internationally. With this prospective cohort study, we aimed to assess the impact of an OPAT service as part of antimicrobial stewardship (AMS) and evaluate the safety and efficiency of the program while illuminating the financial benefit for the hospital.

METHODS

Socio-demographic data, treatment regimen and outcomes were prospectively recorded for all patients assigned to the program of the OPAT unit of the University Hospital of Zurich between November 2018 and September 2022.

RESULTS

In total, we recorded 303 OPAT assignments of which 260 resulted in effective OPAT episodes. The 260 OPAT episodes were further optimized toward the choice of antimicrobial agent (n = 18) and length of therapy (n = 6). Moreover, OPAT resulted in alteration of patient assessment and care led by AMS strategies in 247 of 260 episodes (95%). While the bed days saved per year increased consistently with time, a total of 3934 in-hospital treatment days were saved amounting to a cost saving of 9,835,000 CHF over 47 months. Adverse events were recorded in 46 cases whilst only two of these have been the reason for readmission during OPAT treatment. Clinical cure was noted in 77% (199/260) and was negatively associated with Charlson Comorbidity Index (CCI; OR per 1 unit higher 0.85 (95% CI 0.78-0.93)).

CONCLUSION

This study demonstrates the impact of an OPAT service in the framework of AMS as well as its benefits for the hospital whilst preserving safety and efficacy for the patient's parenteral antimicrobial treatment.

Efficacy of empirical Ciprofloxacin or Cefixime plus Metronidazole therapy for the treatment of liver abscess: a randomized control clinical trial

Liver abscess is a potentially life-threatening medical emergency. Prompt empirical antimicrobial with or without percutaneous aspiration or drainage is therapeutic. The rational for using empirical intravenous broad-spectrum antimicrobials upfront instead of oral Fluoroquinolone or Cephalosporin is contentious. In this double blind randomized control clinical trial 69 participants received Ciprofloxacin (500 mg q 12 hourly) and 71 participants received Cefixime (200 mg q 12 hourly) orally for 2 weeks. Both the group received oral Metronidazole (800 mg q 8 hourly) for 2 weeks and percutaneous drainage or aspiration of the abscess was done as per indication and followed-up for 8 weeks. Out of 140 participants, 89.3% (N = 125) achieved clinical cure, 59 (85.5%) in Ciprofloxacin group and 66 (93%) in Cefixime group (p = 0.154). Mean duration of antimicrobial therapy was 16.2 ± 4.3 days, 15.1 ± 4.5 days in Ciprofloxacin group and 16.0 ± 4.2 days in Cefixime group (p = 0.223). Total 15 (10.7%) participants had treatment failure, 10 (14.5%) in Ciprofloxacin group and 5 (7.0%) in Cefixime group (p = 0.154). The most common reason for treatment failure was need of prolong (> 4 weeks) antimicrobial therapy due to persistent hepatic collection requiring drainage, which was significantly (p = 0.036) higher in Ciprofloxacin (14.5%, N = 10) group, compared to the Cefixime (4.2%, N = 3) group. In conclusion, both, the Ciprofloxacin or Cefixime plus Metronidazole for duration of 2-3 weeks were efficacious as empirical oral antimicrobial regimen along with prompt percutaneous drainage or aspiration for the treatment of uncomplicated liver abscess with similar efficacy. Oral Cefixime was better than Ciprofloxacin in term of lesser chance of treatment failure due to persistent collection which is required to be investigated further in larger clinical trial.Trial registration: clinicaltrials.gov PRS ID: NCT03969758, 31/05/2019.

The Rapid Emergence of Hypervirulent Klebsiella Species and Burkholderia pseudomallei as Major Health Threats in Southeast Asia: The Urgent Need for Recognition as Neglected Tropical Diseases

The World Health Organization (WHO)'s list of neglected tropical diseases (NTDs) highlights conditions that are responsible for devastating health, social and economic consequences, and yet, they are overlooked and poorly resourced. The NTD list does not include conditions caused by Gram-negative bacilli (GNB). Infections due to GNB cause significant morbidity and mortality and are prevalent worldwide. Southeast Asia is a WHO region of low- and middle-income countries carrying the largest burden of NTDs. Two significant health threats in Southeast Asia are Burkholderia pseudomallei (causing melioidosis) and hypervirulent Klebsiella pneumoniae (HvKp). Both diseases have high mortality and increasing prevalence, yet both suffer from a lack of awareness, significant under-resourcing, incomplete epidemiological data, limited diagnostics, and a lack of evidence-based treatment. Emerging evidence shows that both melioidosis and HvKp are spreading globally, including in high-income countries, highlighting the potential future global threat they pose. In this article, we review both conditions, identifying current trends and challenges in Southeast Asia and areas for future research. We also argue that melioidosis and HvKp merit inclusion as NTDs, and that mandatory global surveillance and reporting systems should be established, and we make an urgent call for research to better understand, detect, and treat these neglected diseases.

Carbapenem-resistant hypervirulent ST23 Klebsiella pneumoniae with a highly transmissible dual-carbapenemase plasmid in Chile

BACKGROUND

The convergence of hypervirulence and carbapenem resistance in the bacterial pathogen Klebsiella pneumoniae represents a critical global health concern. Hypervirulent K. pneumoniae (hvKp) strains, frequently from sequence type 23 (ST23) and having a K1 capsule, have been associated with severe community-acquired invasive infections. Although hvKp were initially restricted to Southeast Asia and primarily antibiotic-sensitive, carbapenem-resistant hvKp infections are reported worldwide. Here, within the carbapenemase production Enterobacterales surveillance system headed by the Chilean Public Health Institute, we describe the isolation in Chile of a high-risk ST23 dual-carbapenemase-producing hvKp strain, which carbapenemase genes are encoded in a single conjugative plasmid.

RESULTS

Phenotypic and molecular tests of this strain revealed an extensive resistance to at least 15 antibiotic classes and the production of KPC-2 and VIM-1 carbapenemases. Unexpectedly, this isolate lacked hypermucoviscosity, challenging this commonly used hvKp identification criteria. Complete genome sequencing and analysis confirmed the K1 capsular type, the KpVP-1 virulence plasmid, and the GIE492 and ICEKp10 genomic islands carrying virulence factors strongly associated with hvKp. Although this isolate belonged to the globally disseminated hvKp clonal group CG23-I, it is unique, as it formed a clade apart from a previously reported Chilean ST23 hvKp isolate and acquired an IncN KPC-2 plasmid highly disseminated in South America (absent in other hvKp genomes), but now including a class-I integron carrying blaVIM-1 and other resistance genes. Notably, this isolate was able to conjugate the double carbapenemase plasmid to an E. coli recipient, conferring resistance to 1st -5th generation cephalosporins (including combinations with beta-lactamase inhibitors), penicillins, monobactams, and carbapenems.

CONCLUSIONS

We reported the isolation in Chile of high-risk carbapenem-resistant hvKp carrying a highly transmissible conjugative plasmid encoding KPC-2 and VIM-1 carbapenemases, conferring resistance to most beta-lactams. Furthermore, the lack of hypermucoviscosity argues against this trait as a reliable hvKp marker. These findings highlight the rapid evolution towards multi-drug resistance of hvKp in Chile and globally, as well as the importance of conjugative plasmids and other mobile genetic elements in this convergence. In this regard, genomic approaches provide valuable support to monitor and obtain essential information on these priority pathogens and mobile elements.

Hypervirulent Klebsiella pneumoniae employs genomic island encoded toxins against bacterial competitors in the gut

The hypervirulent lineages of Klebsiella pneumoniae (HvKp) cause invasive infections such as Klebsiella-liver abscess. Invasive infection often occurs after initial colonization of the host gastrointestinal tract by HvKp. Over 80% of HvKp isolates belong to the clonal group 23 sublineage I that has acquired genomic islands (GIs) GIE492 and ICEKp10. Our analysis of 12 361 K. pneumoniae genomes revealed that GIs GIE492 and ICEKp10 are co-associated with the CG23-I and CG10118 HvKp lineages. GIE492 and ICEKp10 enable HvKp to make a functional bacteriocin microcin E492 (mccE492) and the genotoxin colibactin, respectively. We discovered that GIE492 and ICEKp10 play cooperative roles and enhance gastrointestinal colonization by HvKp. Colibactin is the primary driver of this effect, modifying gut microbiome diversity. Our in vitro assays demonstrate that colibactin and mccE492 kill or inhibit a range of Gram-negative Klebsiella species and Escherichia coli strains, including Gram-positive bacteria, sometimes cooperatively. Moreover, mccE492 and colibactin kill human anaerobic gut commensals that are similar to the taxa found altered by colibactin in the mouse intestines. Our findings suggest that GIs GIE492 and ICEKp10 enable HvKp to kill several commensal bacterial taxa during interspecies interactions in the gut. Thus, acquisition of GIE492 and ICEKp10 could enable better carriage in host populations and explain the dominance of the CG23-I HvKp lineage.

Antibiotic treatment durations for pyogenic liver abscesses: A systematic review

Background

We sought to systematically review the existing research on pyogenic liver abscesses to determine what data exist on antibiotic treatment durations.

Methods

We conducted a systematic review and meta-analysis of contemporary medical literature from 2000 to 2020, searching for studies of pyogenic liver abscesses. The primary outcome of interest was mean antibiotic treatment duration, which we pooled by random-effects meta-analysis. Meta-regression was performed to examine characteristics influencing antibiotic durations.

Results

Sixteen studies (of 3,933 patients) provided sufficient data on antibiotic durations for pooling in meta-analysis. Mean antibiotic durations were highly variable across studies, from 8.4 (SD 5.3) to 68.9 (SD 30.3) days. The pooled mean treatment duration was 32.7 days (95% CI 24.9 to 40.6), but heterogeneity was very high (I2 = 100%). In meta-regression, there was a non-significant trend towards decreased mean antibiotic treatment durations over later study years (-1.14 days/study year [95% CI -2.74 to 0.45], p = 0.16). Mean treatment duration was not associated with mean age of participants, percentage of infections caused by Klebsiella spp, percentage of patients with abscesses over 5 cm in diameter, percentage of patients with multiple abscesses, and percentage of patients receiving medical management. No randomized trials have compared treatment durations for pyogenic liver abscess, and no observational studies have reported outcomes according to treatment duration.

Conclusions

Among studies reporting on antibiotic durations for pyogenic liver abscess, treatment practices are highly variable. This variability does not seem to be explained by differences in patient, pathogen, abscess, or management characteristics. Future RCTs are needed to guide optimal treatment duration for patients with this complex infection.

Management of Pyogenic Liver Abscesses: Contemporary Strategies and Challenges

Pyogenic liver abscesses (PLAs) are a suppurative infection of the hepatic parenchyma responsible for significant morbidity and mortality. PLAs are categorized into a variety of mechanisms: (1) via the portal vein, (2) through the biliary tract, (3) via the hepatic artery, (4) from trauma, (5) contiguously via direct extension, and (6) cryptogenically. The pathogenesis of PLA, which informs treatment, can often be discerned based on host factors, clinical presentation, and causative microorganisms. The Streptococcus anginosus group, hypervirulent Klebsiella pneumoniae , and multidrug-resistant gram-negative pathogens have emerged as microbiologically challenging organisms to treat. The identification of hypervirulent K. pneumoniae should prompt for assessment for metastatic spread and consideration of prolonged antimicrobial treatment. Abdominal imaging is indispensable in characterizing PLAs and facilitating source control interventions. Source control remains the most critical aspect of PLA management, followed by antimicrobial therapy. Empiric antibiotics for PLAs are informed by the suspected etiology of PLA formation. Duration of antimicrobial therapy is individualized and dependent on multiple components, including the success of achieving source control, host factors, mechanism of PLA development, and the illness course of the individual-factoring in clinical, biochemical, and radiographic parameters.

Cost-minimization analysis of oral versus intravenous antibiotic treatment for Klebsiella pneumoniae liver abscess

A cost-minimization analysis was conducted for Klebsiella pneumoniae liver abscess (KLA) patients enrolled in a randomized controlled trial which found oral ciprofloxacin to be non-inferior to intravenous (IV) ceftriaxone in terms of clinical outcomes. Healthcare service utilization and cost data were obtained from medical records and estimated from self-reported patient surveys in a non-inferiority trial of oral ciprofloxacin versus IV ceftriaxone administered to 152 hospitalized adults with KLA in Singapore between November 2013 and October 2017. Total costs were evaluated by category and payer, and compared between oral and IV antibiotic groups over the trial period of 12 weeks. Among the subset of 139 patients for whom cost data were collected, average total cost over 12 weeks was $16,378 (95% CI, $14,620-$18,136) for the oral ciprofloxacin group and $20,569 (95% CI, $18,296-$22,842) for the IV ceftriaxone group, largely driven by lower average outpatient costs, as the average number of outpatient visits was halved for the oral ciprofloxacin group. There were no other statistically significant differences, either in inpatient costs or in other informal healthcare costs. Oral ciprofloxacin is less costly than IV ceftriaxone in the treatment of Klebsiella liver abscess, largely driven by reduced outpatient service costs.Trial registration: ClinicalTrials.gov Identifier NCT01723150 (7/11/2012).

Klebsiella invasive syndrome: a challenging diagnosis

Klebsiella invasive syndrome is a rare condition that typically presents as a liver abscess with metastatic infection, with mortality rates as high as 14% potentially due to diagnostic delay by clinicians. Here, we present a case of a woman in her 60s, who presented with symptoms and signs consistent with meningitis, imaging findings suggestive of possible leptomeningeal carcinomatosis a long with areas of lung consolidation and abdominal nodules and lymphadenopathy, presumably metastatic malignancy. We diagnosed Klebsiella invasive syndrome and treated it conservatively with medical management, including a long course of intravenous antibiotic therapy and supportive care. This is an infrequently encountered clinical entity with potentially fatal consequences, and we hope to add to the existing literature on the subject and drive home the point that it should be considered in the differential diagnoses in the appropriate clinical scenario.

Liver Abscess Caused by Klebsiella Pneumoniae in the Absence of Hepatobiliary Disease

Klebsiella pneumoniae is notorious for causing abscesses in patients without any previous hepatobiliary disease and is a cause of liver abscesses. We report the case of a 70-year-old man with a past medical history of hypertension and benign prostatic hyperplasia who presented with a cough and fever lasting two weeks. The findings from his physical examination were unremarkable, but his laboratory investigations were significant for elevated inflammatory markers. A computed tomography scan of his abdomen revealed a complex septated cyst in the right lobe of his liver, and his blood culture was positive for K. pneumoniae. He responded well to drainage and intravenous and oral antibiotics. His abscess resolved fully. Cases of K. pneumoniae in the United States are rare, and studies are necessary to explore its epidemiology. Atypical symptoms make diagnosis a challenge, and physicians are urged to retain high levels of suspicion to diagnose and treat such cases early.

Current Positioning against Severe Infections Due to Klebsiella pneumoniae in Hospitalized Adults

Infections due to Klebsiella pneumoniae have been increasing in intensive care units (ICUs) in the last decade. Such infections pose a serious problem, especially when antimicrobial resistance is present. We created a task force of experts, including specialists in intensive care medicine, anaesthesia, microbiology and infectious diseases, selected on the basis of their varied experience in the field of nosocomial infections, who conducted a comprehensive review of the recently published literature on the management of carbapenemase-producing Enterobacterales (CPE) infections in the intensive care setting from 2012 to 2022 to summarize the best available treatment. The group established priorities regarding management, based on both the risk of developing infections caused by K. pneumoniae and the risk of poor outcome. Moreover, we reviewed and updated the most important clinical entities and the new antibiotic treatments recently developed. After analysis of the priorities outlined, this group of experts established a series of recommendations and designed a management algorithm.

Cefazolin versus ceftriaxone as definitive treatment for Klebsiella pneumoniae bacteraemia: a retrospective multicentre study in Singapore

BACKGROUND

Ceftriaxone is the preferred treatment for bacteraemia caused by non-MDR (antibiotic-susceptible) Klebsiella pneumoniae. Excessive and widespread ceftriaxone use creates selection pressure for ESBLs. Cefazolin is an alternative, although there are theoretical concerns that SHV-1 β-lactamase in K. pneumoniae may inactivate cefazolin in an inoculum-dependent manner.

OBJECTIVES

In this retrospective study, we investigated the outcomes in K. pneumoniae bacteraemia patients treated with IV cefazolin versus IV ceftriaxone as definitive therapy.

METHODS

A total of 917 patients infected with K. pneumoniae from 1 January to 31 December 2016 in three public acute care hospitals in Singapore were screened for study eligibility. Consecutive unique episodes of monomicrobial bacteraemia caused by cefazolin- and/or ceftriaxone-susceptible K. pneumoniae were analysed (n = 284).

RESULTS

There were 143 patients (50.4%) in the cefazolin group and 141 patients (49.6%) in the ceftriaxone group. Demographics, baseline illness severity and risk factors for healthcare-associated bacteraemia were comparable in the two treatment groups. The primary outcome of 28 day all-cause mortality was not significantly different between the cefazolin and ceftriaxone groups (10.5% versus 7.1%, P = 0.403). Both in the crude analysis and using a multivariable logistic regression model with inverse probability weighting based on propensity score, cefazolin treatment was not associated with increased risk of 28 day mortality (OR 1.51 with ceftriaxone as the reference group, 95% CI 0.67-3.53; adjusted OR 1.55, 95% CI 0.33-7.40).

CONCLUSIONS

Cefazolin may be a ceftriaxone-sparing alternative treatment for antibiotic-susceptible K. pneumoniae bacteraemia. This observation may provide sufficient clinical equipoise for a randomized controlled trial.

Utility of Acute Physiology and Chronic Health Evaluation (APACHE II) in Predicting Mortality in Patients with Pyogenic Liver Abscess: A Retrospective Study

Pyogenic liver abscess (PLA) is a major life-threatening disease with varied clinical features. This study aimed to determine predictors of mortality in patients with PLA using criteria determined upon admission. We retrospectively examined the data of 324 hospitalized adults in whom liver abscesses were confirmed using abdominal ultrasound and/or computed tomography. The relationship between various risk factors was assessed using multivariate analysis. A total of 109 (33.6%) patients were admitted to the intensive care unit (ICU). The overall mortality rate was 7.4% and was higher among ICU patients than non-ICU patients (21.1% vs. 0.5%, p < 0.001). PLA patients with an Acute Physiology and Chronic Health Evaluation (APACHE) II score ≥18 had a 19.31-fold increased risk, and those with concomitant infections had a 34.33-fold increased risk of 30-day mortality according to multivariate analysis. The estimated area under the receiver operating characteristic curve for predicting 30-day mortality revealed that APACHE II score ≥18 (sensitivity of 75% and specificity of 84%, p < 0.0001) had better discriminative power than Sequential Organ Failure Assessment (SOFA) ≥6 (sensitivity of 81% and specificity of 66%, p < 0.0001). APACHE II has shown better discrimination ability than SOFA in predicting mortality in PLA patients. To improve outcomes in patients with PLA, future management strategies should focus on high-risk patients.

Measuring antimicrobial prescribing quality in outpatient parenteral antimicrobial therapy (OPAT) services: development and evaluation of a dedicated national antimicrobial prescribing survey

Background

Antimicrobial stewardship programmes are important in driving safety and quality of antimicrobial prescribing. The National Antimicrobial Prescribing Survey (NAPS) is a point-prevalence audit of inpatient antimicrobial prescribing in Australian hospitals.

Objectives

To design and adapt the NAPS tool for use in the outpatient parenteral antimicrobial therapy (OPAT) and hospital-in-the-home (HITH) setting.

Methods

An inter-disciplinary working group with expertise in OPAT and HITH services was established to adapt the NAPS template for use in the OPAT setting—called HITH-NAPS. This was initially trialled in 5 HITH services, subsequently adapted following participant feedback, then offered nationally to 50 services in 2017.

Results

There were 1154 prescriptions for 715 patients audited via the HITH-NAPS. The most common antimicrobials prescribed were cefazolin (22%), flucloxacillin (12%), piperacillin/tazobactam (10%) and ceftriaxone (10%). The most common infections treated were cellulitis (30%) and respiratory tract infections (14%). Eighty-seven percent of prescriptions were assessed as appropriate, 11% inappropriate and 2% not assessable. Prolonged durations of antimicrobials and unnecessarily broad-spectrum antibiotics were used in 9% of prescriptions.

Conclusions

The HITH-NAPS pilot project revealed that auditing of this type is feasible in HITH. It showed that antibiotic use in these HITH services was generally appropriate, but there are some areas for improvement. A national OPAT/HITH-NAPS can facilitate benchmarking between services, identify potentially inappropriate prescribing and help guide quality improvement.

Fluoroquinolones as an alternative treatment for Klebsiella pneumoniae liver abscess and impact on hospital length of stay

Klebsiella pneumoniae liver abscess (KPLA) is an endemic disease in East Asia. Patients with KPLA usually require prolonged intravenous (i.v.) β-lactam therapy and hospitalisation. Fluoroquinolones have high oral bioavailability and the potential to shorten the duration of i.v. therapy. The aim of this study was to investigate the feasibility of fluoroquinolones as an alternative treatment for KPLA in Taiwan. Consecutive patients with KPLA in a medical centre in Taiwan between July 2012 and August 2019 were retrospectively enrolled. Clinical characteristics and outcomes were compared between cases treated with β-lactams and fluoroquinolones. A multivariate logistic regression model and propensity-score adjusted analysis were performed to identify independent risk factors for prolonged hospitalisation. A total of 234 patients with KPLA were identified during the study period. Most patients received β-lactams (n = 199; 85.0%), whilst only 35 (15.0%) received fluoroquinolones as the major therapy. Fluoroquinolones had similar clinical efficacy to β-lactams even in critically ill patients. Patients treated with fluoroquinolones had a shorter i.v. antibiotics duration (18.9 ± 7.6 days vs. 28.5 ± 14.7 days; P < 0.001) and hospital length of stay (LOS) (20.9 ± 8.3 days vs. 29.5 ± 16.2 days; P < 0.001) than patients treated with β-lactams. Major therapy with fluoroquinolones was an independent protective factor for hospital LOS > 14 days in all patients and for hospital LOS > 21 days in critically ill patients. In conclusion, fluoroquinolones were an effective alternative treatment for KPLA that resulted in a shorter duration of i.v. therapy and hospital LOS.