Population pharmacokinetic/pharmacodynamic target attainment analysis of IV fosfomycin for the treatment of MDR Gram-negative bacterial infections

BACKGROUND

IV fosfomycin is used against MDR Gram-negative bacilli (GNB) but has dose-limiting side effects, especially in patients with impaired kidney function.

OBJECTIVES

To determine the optimal dosage of IV fosfomycin for patients with varying degrees of kidney function.

METHODS

Adult patients receiving IV fosfomycin for treatment of GNB were eligible. Five serial blood samples were collected after at least three doses of fosfomycin; plasma was assayed by LC-MS/MS and modelled by population pharmacokinetic analysis. The PTA for AUC24/MIC of 98.9 for Escherichia coli and Klebsiella pneumoniae, and 40.8 for Pseudomonas aeruginosa were computed by Monte Carlo simulations. Cumulative fractions of response (CFR) were analysed for each pathogen using EUCAST MIC distributions.

RESULTS

A total of 24 patients were included. Creatinine clearance (CLCR) and gender significantly influenced fosfomycin clearance. The kidney function-adjusted dosing regimens are proposed by using the lowest dose that can achieve ≥90% PTA for AUC24/MIC of 98.9 at an MIC of ≤32 mg/L (EUCAST v.13 susceptibility breakpoint for Enterobacterales). For patients with normal kidney function (CLCR 91-120 mL/min), a dosage of 15 g/day is suggested. This regimen achieved 97.1% CFR against E. coli, whereas CFR was 72.9% for K. pneumoniae and 76.7% for P. aeruginosa.

CONCLUSIONS

A fosfomycin dosage of 15 g/day with adjustment according to kidney function provided high PTA and CFR when treating E. coli. This dosage is lower than that used in current practice and may improve tolerability. Higher dosages may be needed for P. aeruginosa; however, safety data are limited.

A comparison of strategies for identifying patients at risk for carbapenem-resistant or extended β-lactam-resistant Pseudomonas aeruginosa

OBJECTIVES

To assess risk factors for carbapenem-resistant Pseudomonas aeruginosa (CR) and extended-β-lactam-resistant P. aeruginosa (EBR) infection/colonization, and to develop and compare tools for predicting isolation of CR and EBR from clinical cultures.

METHODS

This retrospective study analysed hospitalized patients with positive P. aeruginosa cultures between 2015 and 2021. Two case-control analyses were performed to identify risk factors and develop scoring tools for distinguishing patients with CR versus carbapenem-susceptible (CS) P. aeruginosa and EBR versus CS P. aeruginosa. The performance of institutionally derived scores, externally derived scores and the presence/absence of key risk factors to predict CR and EBR were then compared.

RESULTS

A total of 2379 patients were included. Of these, 8.3% had a positive culture for CR, 5.0% for EBR and 86.7% for CS P. aeruginosa. There was substantial overlap in risk factors for CR and EBR. Institutional risk scores demonstrated modestly higher area under the ROC curve values than external scores for predicting CR (0.67 versus 0.58) and EBR (0.76 versus 0.70). Assessing the presence/absence of ≥1 of the two strongest predictors (prior carbapenem use or CR isolation within 90 days) was slightly inferior to scoring tools for predicting CR, and comparable for predicting EBR.

CONCLUSIONS

Clinicians concerned about CR in P. aeruginosa should consider the likelihood of EBR when making treatment decisions. A simple approach of assessing recent history of CR isolation or carbapenem usage performed similarly to more complex scoring tools and offers a more pragmatic way of identifying patients who require coverage for resistant P. aeruginosa.

Case Commentary: When Voldemort Meets Sauron: Treatment Considerations for Emerging Dual-Carbapenemase-Producing Extensively Drug-Resistant Pseudomonas aeruginosa

Infections caused by extensively drug-resistant Pseudomonas aeruginosa are difficult to treat due to limited effective treatment options. In this issue, a patient with a corneal infection caused by a Verona integron-encoded metallo-β-lactamase (VIM)- and Guiana extended-spectrum β-lactamase (GES)-coproducing P. aeruginosa strain associated with the recent artificial tears-related outbreak in the United States is described. This resistance genotype/phenotype further compromises therapeutic options, and this report provides insights into diagnostic and treatment approaches for clinicians dealing with infections due to this highly resistant P. aeruginosa.

937. Appropriateness of using a Mobile Application for Choosing Antibiotic Therapy in Hospitalized Patients at Siriraj Hospital

Background

Development of facility-specific clinical practice guidelines and incorporation of computerized clinical decision support have been recommended as the effective antimicrobial stewardship strategies. The DigitalAMSTM is a mobile-based application used to guide choosing empirical antibiotics. Before the hospital-wide implementation of DigitalAMSTM, the appropriateness and limitation of such an application needs to be evaluated.

Methods

A retrospective cross-sectional study of hospitalized adult patients who received at least one dose of antibiotic and had at least one documented site of infection were enrolled between 1 Jan and 31 Jun 2018. All necessary data was obtained via chart review. The antibiotic regimen that was prescribed by the ward physician (WARD), the regimen recommended by the DigitalAMSTM (APP), the regimen recommended by the independent infectious disease (ID) physicians before and after knowing the culture results (Emp-ID and Def-ID) were compared.

Results

A total of 401 patients of the targeted infections i.e. 98 subjects with pneumonia, 103 subjects with urinary tract infection (UTI), 98 subjects with bacteremia and 102 subjects with skin and soft tissue infection (SSTI) were enrolled. The percent agreement between the APP and the WARD was less than half in all sites of infection. The APP regimen provided approximately 80% agreement with the Emp-ID regimen among subjects with UTI (78.6%), bacteremia (85.7%) and SSSI (85.2%), while the percent agreement of the WARD regimen and the Emp-ID was approximately half in all sites of infection. The lowest percent agreement between the APP regimen and the Emp-ID regimen was found among subjects with pneumonia (59.1%). Univariate analysis did not reveal any association between subjects who received the antibiotic regimen matching to the APP recommendation and the 28-day mortality.

Conclusion

Our study confirmed that the DigitalAMSTM application could improve appropriateness of antibiotic regimens for empirical therapy for four common infections among adult hospitalized patients at Siriraj Hospital. However, some revisions need to be done to improve the appropriateness of antibiotic regimens in the APP, especially for subjects with pneumonia.

Disclosures

All Authors: No reported disclosures.

Active Surveillance for Carbapenem-Resistant Enterobacterales (CRE) Colonization and Clinical Course of CRE Colonization among Hospitalized Patients at a University Hospital in Thailand

Optimal measures for preventing and controlling carbapenem-resistant Enterobacterales (CRE) depend on their burden. This prospective observational study investigated the prevalence and clinical course of CRE colonization in hospitalized patients at Siriraj Hospital, the largest university hospital in Thailand. Stool/rectal swab samples were collected from the patients upon admission, once weekly during hospitalization and every 1–3 months after discharge, to determine the presence of CRE in the stool. Between 2018 and 2021, a total of 528 patients were included. The prevalence of CRE colonization upon admission was 15.5%, while 28.3% of patients who tested negative for CRE on admission acquired CRE during their hospitalization. CRE colonization upon admission was usually associated with prior healthcare exposure. Among CRE-colonized patients, 4.7% developed a CRE clinical infection, with 60% mortality. No cutoff period that ensured that patients were free of CRE colonization in stool was identified, and isolation precautions should only be ceased if stool tests are negative for CRE. In conclusion, the prevalence of CRE colonization among hospitalized patients at Siriraj Hospital is high. CRE-colonized patients are at risk of developing subsequent CRE infection. To prevent CRE transmission within the hospital, patients at high risk of colonization should undergo CRE screening upon admission.

JMM Profile: Fosfomycin: a potential antibiotic for multi- and extensively resistant bacteria

Fosfomycin (FOF) is the first antimicrobial of the epoxide class. It is commercially available in oral and parenteral formulations. Oral FOF is widely used to treat uncomplicated cystitis in women, while parenteral FOF is extensively utilized for upper urinary tract infections. FOF has a broad-spectrum bactericidal activity with a low risk of cross-resistance to other antimicrobial classes. Therefore, parenteral FOF is increasingly prescribed adjunctive therapy to treat extra-urinary tract infections caused by multidrug-resistant, Gram-negative bacteria.

Implementation of Clinical Practice Guidelines for Empirical Antibiotic Therapy of Bacteremia, Urinary Tract Infection, and Pneumonia: A Multi-Center Quasi-Experimental Study

A quasi-experimental study was conducted on the implementation of locally developed clinical practice guidelines (CPGs) for empirical antibiotic (ATB) therapy of common infections (bacteremia, urinary tract infection (UTI), pneumonia) in the hospitals from January 2019 to December 2020. The CPGs were developed using data from patients with these infections at individual hospitals. Relevant CPG data pre- and post-implementation were collected and compared. Of the 1644 patients enrolled in the study, 808 and 836 were in the pre- and post-implementation periods, respectively, and patient outcomes were compared. Significant reductions in the mean durations of intensive care unit stay (3.44 ± 9.08 vs. 2.55 ± 7.89 days; p = 0.035), ventilator use (5.73 ± 12.14 vs. 4.22 ± 10.23 days; p = 0.007), piperacillin/tazobactam administration (0.954 ± 3.159 vs. 0.660 ± 2.217 days, p = 0.029), and cefoperazone/sulbactam administration (0.058 ± 0.737 vs. 0.331 ± 1.803 days, p = 0.0001) occurred. Multivariate analysis demonstrated that CPG-implementation was associated with favorable clinical outcomes (adjusted odds ratio 1.286, 95% confidence interval: 1.004–1.647, p = 0.046). Among patients who provided follow-up cultures (n = 284), favorable microbiological responses were significantly less frequent during the pre-implementation period than the post-implementation period (80.35% vs. 91.89%; p = 0.01). In conclusion, the locally developed CPG implementation is feasible and effective in improving patient outcomes and reducing ATB consumption. Hospital antimicrobial stewardship teams should be able to facilitate CPG development and implementation for antimicrobial therapy for common infections.

Epidemiology of Carbapenem-Resistant Enterobacterales Infection and Colonization in Hospitalized Patients at a University Hospital in Thailand

Purpose

To investigate the epidemiology of carbapenem-resistant Enterobacterales (CRE) colonization or CRE infection relative to the natural history and clinical course of CRE colonization or CRE infection in hospitalized patients during admission and after discharge.

Material and Methods

Two adult cohorts were enrolled. Cohort I comprised hospitalized patients who had CRE isolated from their clinical specimens during 2018–2020. CRE colonization or CRE infection was based on the absence/presence of clinical features of infection. Information regarding the natural history and clinical course of these patients was collected during hospitalization. Stool samples were evaluated for CRE once a week during hospitalization, and then once every few months after discharge until negative for CRE. Cohort II comprised patients who had CRE isolated from clinical specimens during hospitalization and who were discharged during 2015–2018. CRE in stool samples collected from these patients every few months was assessed to determine duration of CRE in stool.

Results

CRE in stool was detected in 69.7% of 353 patients in cohort I. K. pneumoniae was the predominant CRE isolated from clinical samples (76.8%) and stool samples (65.7%). Among the 225 CRE-colonized patients, 20.4% developed subsequent CRE infections with a median duration from CRE colonization to CRE infection of 14 days. Among 174 CRE-infected patients, the most common infection was pneumonia with mortality at discharge of 47.7%. Duration of CRE colonization in stool was <1 year in 50.0% of cohort I patients, and <2 years in 91.4% of patients in cohort II.

Conclusion

CRE isolated from clinical specimens in hospitalized patients are more likely to cause colonization than infection. Patients with CRE colonization are at risk of subsequent CRE infection with high mortality. Stool culture for CRE is needed to verify if contact precautions can be discontinued because the duration of CRE colonization in stool varied from days to years.

Rat bite fever due to Streptobacillus notomytis complicated by meningitis and spondylodiscitis: a case report

BACKGROUND

Only three other cases of rat bite fever caused by Streptobacillus notomytis in humans have been reported since this species was identified in 2015. Data specific to the differences in clinical features and geographic distribution between S. notomytis infection and S. moniliformis infection are scarce. All previous cases of human S. notomytis infection were reported from Japan. This is the first case of S. notomytis infection reported from outside of Japan.

CASE PRESENTATION

A 72-year-old Thai woman was admitted to Siriraj Hospital (Bangkok, Thailand)-Thailand's largest university-based national tertiary referral center-in August 2020 with fever, myalgia, and polyarthralgia for 3 days, and gradually decreased consciousness for the past 1 day. Physical examination and laboratory investigations revealed septic arthritis of both knee joints, meningitis, and hepatitis. She was initially misdiagnosed as rheumatoid arthritis in the elderly since the initial investigations were unable to detect a causative pathogen. However, S. notomytis infection was later confirmed by polymerase chain reaction amplification of a part of the 16S rRNA gene and sequencing from synovial fluid. Her clinical course was also complicated by spondylodiscitis and epidural abscess caused by S. notomytis, which was detected from tissue biopsy. Therefore, rat bite fever in this patient manifested as meningitis, septic polyarthritis, hepatitis, and spondylodiscitis. The patient was treated with intravenous ceftriaxone then switched to oral amoxicillin with complete recovery.

CONCLUSIONS

The clinical manifestations of S. notomytis infection are similar to those demonstrated in S. moniliformis infection. This case also showed that arthritis caused by S. notomytis mimics rheumatoid arthritis, and that meningitis and spondylodiscitis are potential coexisting complications that can be found in S. notomytis infection.

Optical DNA Mapping of Plasmids Reveals Clonal Spread of Carbapenem-Resistant Klebsiella pneumoniae in a Large Thai Hospital

Carbapenem-resistant Klebsiella pneumoniae (CR-KP) in patients admitted to hospitals pose a great challenge to treatment. The genes causing resistance to carbapenems are mostly found in plasmids, mobile genetic elements that can spread easily to other bacterial strains, thus exacerbating the problem. Here, we studied 27 CR-KP isolates collected from different types of samples from 16 patients admitted to the medical ward at Siriraj Hospital in Bangkok, Thailand, using next generation sequencing (NGS) and optical DNA mapping (ODM). The majority of the isolates belonged to sequence type (ST) 16 and are described in detail herein. Using ODM, we identified the plasmid carrying the bla_NDM-1 gene in the ST16 isolates and the plasmids were very similar, highlighting the possibility of using ODM of plasmids as a surrogate marker of nosocomial spread of bacteria. We also demonstrated that ODM could identify that the bla_CTX-M-15 and bla_OXA-232 genes in the ST16 isolates were encoded on separate plasmids from the bla_NDM-1 gene and from each other. The other three isolates belonged to ST147 and each of them had distinct plasmids encoding bla_NDM-1.

Epidemiology, clinical characteristics, and treatment outcomes of patients with COVID-19 at Thailand's university-based referral hospital

Background

The epidemiology and outcomes of COVID-19 patients in Thailand are scarce.

Methods

This retrospective cohort study included adult hospitalized patients who were diagnosed with COVID-19 at Siriraj Hospital during February 2020 to April 2020.

Results

The prevalence of COVID-19 was 7.5% (107 COVID-19 patients) among 1409 patients who underwent RT-PCR for SARS-CoV-2 detection at our hospital during the outbreak period. Patients with COVID-19 presented with symptoms in 94.4%. Among the 104 patients who were treated with antiviral medications, 78 (75%) received 2-drug regimen (lopinavir/ritonavir or darunavir/ritonavir plus chloroquine or hydroxychloroquine), and 26 (25%) received a 3-drug regimen with favipiravir added to the 2-drug regimen. Disease progression was observed in 18 patients (16.8%). All patients with COVID-19 were discharged alive.

Conclusions

The prevalence of COVID-19 was 7.5% among patients who underwent RT-PCR testing, and 10% among those having risk factors for COVID-19 acquisition. Combination antiviral therapies for COVID-19 patients were well-tolerated and produced a favorable outcome.

Diagnostic and Prognostic Utility Compared Among Different Sepsis Scoring Systems in Adult Patients With Sepsis in Thailand: A Prospective Cohort Study

Background

The diagnostic and prognostic utility of various sepsis scores varied among different cohorts and settings.

Methods

A prospective cohort study in adult patients with sepsis at Siriraj Hospital (Bangkok, Thailand) was conducted during January to July 2019. The performance of sepsis assessments, including systemic inflammatory response syndrome (SIRS) score, sequential organ failure assessment (SOFA) score, quick sepsis-related organ failure assessment (qSOFA) score, modified early warning score (MEWS), and national early warning score (NEWS), for sepsis detection and mortality prediction were compared with agreement between 2 infectious disease (ID) specialists to determine their sepsis and septic shock status as the reference standard.

Results

Among the 470 subjects included in this study, 206 patients (43.8%) were determined by 2 ID specialists to have sepsis. Systemic inflammatory response syndrome ≥2, qSOFA ≥2, and NEWS ≥5 yielded the highest sensitivity (93.2%), specificity (81.3%), and accuracy (72.6%), respectively, for detecting sepsis. The SIRS ≥2 had the highest sensitivity (97.8%), whereas qSOFA ≥2 had the highest specificity (61%) and accuracy (69.7%) for predicting mortality among sepsis patients. Receiver operating characteristic (ROC) curve showed MEWS to have the highest discriminatory power for sepsis detection (area under the ROC curve [AUROC], 0.79; 95% confidence interval [CI], 0.74–0.83), whereas SOFA had the highest discriminatory power for predicting hospital mortality (AUROC, 0.76; 95% CI, 0.69–0.79).

Conclusions

The NEWS ≥5 and qSOFA ≥2 were the most accurate scoring systems for sepsis detection and mortality prediction, respectively. Each scoring system is useful for different specific purposes relative to early detection and mortality prediction in sepsis patients.

Disseminated histoplasmosis in a kidney transplant patient

Patients with impaired cell-mediated immunity have a higher risk of developing histoplasmosis; however, histoplasmosis after solid organ transplantation is rare. In Thailand, histoplasmosis cases are sporadic, and most cases are associated with human immunodeficiency virus (HIV) infection. Herein, we report a case of disseminated histoplasmosis in a kidney transplant Thai recipient diagnosed by fungal staining of fungal culture from bronchoalveolar lavage and bone marrow biopsy. Liposomal amphotericin B was given followed by oral itraconazole. The patient's clinical condition was improved; however, his graft function was irreversibly declined. The majority of histoplasmosis cases after solid organ transplant presented with disseminated disease with pulmonary involvement. Even in a non-endemic area of histoplasmosis, suspected cases should be early diagnosed and promptly managed in order to reduce morbidity and mortality, especially in cell-mediated immunity defect patients like solid organ transplant recipients.

Collateral damage of using colistin in hospitalized patients on emergence of colistin-resistant Escherichia coli and Klebsiella pneumoniae colonization and infection

Background

Colistin has been used for therapy of carbapenem-resistant Gram-negative infections in Thailand, especially carbapenem-resistant A. baumannii and P. aeruginosa, for more than 10 years. However, the prevalence of colistin-resistant A. baumannii or P. aeruginosa is still less than 5%. Colistin-resistant Enterobacteriaceae has been increasingly reported globally over the past few years and the use of colistin in food animals might be associated with an emergence of colistin resistance in Enterobacteriaceae. This study aimed to determine the effect of colistin exposure in hospitalized patients who received colistin on development of colistin-resistant (CoR) Escherichia coli (EC) or Klebsiella pneumoniae (KP) colonization and infection.

Methods

A prospective observational study was performed in adult hospitalized patients at Siriraj Hospital who received colistin for treatment of infections during December 2016 and November 2017. The surveillance culture samples were collected from the stool and the site of infection of each patient who received colistin at the study enrollment, days 3 and 7 after the study enrollment, and once a week thereafter for determination of CoR EC and CoR KP. CoR EC and CoR KP were also tested for a presence of mcr-1 gene.

Results

One hundred thirty-nine patients were included. Overall prevalence of CoR EC or CoR KP colonization was 47.5% among 139 subjects. Prevalence of CoR EC or CoR KP colonization was 17.3% of subjects at study enrollment, and 30.2% after study enrollment. Use of fluoroquinolones, aminoglycosides, and colistin was found to be significantly associated with CoR EC or CoR KP colonization. The mcr-1 gene was detected in 13.0% of CoR EC or CoR KP isolates, and in 27.3% of subjects with CoR EC or CoR KP colonization. CoR EC or CoR KP colonization persisted in 65.2% of the subjects at the end of the study. Five patients with CoR KP infections received combination antibiotics and they were alive at hospital discharge.

Conclusions

Prevalence of CoR EC or CoR KP colonization in hospitalized patients receiving colistin was high and it was associated with the use of colistin. Therefore, patients who receive colistin are at risk of developing CoR EC or CoR KP colonization and infection.

Lomentospora prolificans vertebral osteomyelitis with spinal epidural abscess in an immunocompetent woman: Case report and literature review

Lomentospora prolificans is a rare cause of vertebral osteomyelitis. We report a case of L. prolificans thoracic vertebral osteomyelitis with spinal epidural abscess in a patient without apparent immunodeficiency. Clinical manifestations and radiographic findings could not distinguish from other etiologic agents. Treatment is also challenging because L. prolificans is usually resistant to antifungal agents. The patient underwent surgical debridement and has been receiving a prolonged combination of antifungal therapy to prevent an infection relapse.