Infection patterns during the first year after adult liver transplantation: a retrospective analysis

Background

Methods

Results

Conclusions

Clinical impact of and microbiological risk factors for qacA/B positivity in ICU-acquired ST5-methicillin-resistant SCCmec type II Staphylococcus aureus bacteremia

Concern about resistance to chlorhexidine has increased due to the wide use of the latter. The impact of the qacA/B and smr chlorhexidine tolerance genes on the outcome of methicillin-resistant Staphylococcus aureus (MRSA) infections is unclear. We evaluated the prevalence and clinical impact of, and microbiological risk factors for, qacA/B tolerance in MRSA bacteremia. MRSA bacteremia that occurred more than two days after intensive care unit admission between January 2009 and December 2018 was identified from a prospective cohort of S. aureus bacteremia in a tertiary-care hospital from South Korea. A total of 183 MRSA blood isolates was identified, and the major genotype found was ST5-MRSA-II (87.4%). The prevalences of qacA/B and smr were 67.2% and 3.8%, respectively. qacA/B-positive isolates were predominantly ST5-MRSA-II (96.7% [119/123]), the dominant hospital clone. In a homogenous ST5-MRSA-II background, qacA/B positivity was independently associated with septic shock (aOR, 4.85), gentamicin resistance (aOR, 74.43), and non-t002 spa type (aOR, 74.12). qacA/B positivity was found to have decreased significantly in ST5-MRSA-II in association with a decline in qacA/B-positive t2460, despite the increasing use of chlorhexidine since 2010 (P < 0.001 for trend). Continuous surveillance of the qac genes, and molecular characterization of their plasmids, are needed to understand their role in MRSA epidemiology.

Clinical and virological characteristics of SARS-CoV-2 B.1.617.2 (Delta) variant: a prospective cohort study

Background

Data on the clinical and virological characteristics of the Delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are limited. This prospective cohort study compared the characteristics of the Delta variant to other variants.

Methods

Adult patients with mild coronavirus disease 2019 (COVID-19) who agreed to daily saliva sampling at a community isolation facility in South Korea between July and August 2021 were enrolled. Scores of 28 COVID-19-related symptoms were recorded daily. The genomic RNA and subgenomic RNA from saliva samples were measured by real-time reverse-transcription polymerase chain reaction (PCR). Cell cultures were performed on saliva samples with positive genomic RNA results.

Results

A total of 141 patients (Delta group, n = 108 [77%]; non-Delta group, n = 33 [23%]) were enrolled. Myalgia was more common in the Delta group than in the non-Delta group (52% vs 27%, P = .03). Total symptom scores were significantly higher in the Delta group between days 3 and 10 after symptom onset. Initial genomic RNA titers were similar between the 2 groups; however, during the late course of disease, genomic RNA titers were higher in the Delta group. Negative conversion of subgenomic RNA was slower in the Delta group (median 9 vs 5 days; P < .001). The duration of viral shedding in terms of positive viral culture was also longer in the Delta group (median 5 vs 3 days; P = .002).

Conclusions

COVID-19 patients infected with the Delta variant exhibited prolonged viable viral shedding with more severe symptoms than those infected with non-Delta variants.

Fluvoxamine Treatment of Patients with Symptomatic COVID-19 in a Community Treatment Center: A Preliminary Result of Randomized Controlled Trial

Background

This study aimed to evaluate whether fluvoxamine reduces clinical deterioration in adult patients with mild to moderate coronavirus disease 2019 (COVID-19), and to identify risk factors for clinical deterioration in patients admitted to a community treatment center (CTC).

Materials and Methods

A randomized, placebo-controlled trial was conducted in a CTC, in Seoul, Korea from January 15, 2021, to February 19, 2021. Symptomatic adult patients with positive results of severe acute respiratory syndrome coronavirus 2 real time-polymerase chain reaction within 3 days of randomization were assigned at random to receive 100 mg of fluvoxamine or placebo twice daily for 10 days. The primary outcome was clinical deterioration defined by any of the following criteria: oxygen requirement to keep oxygen saturation over 94.0%, aggravation of pneumonia with dyspnea, or World Health Organization clinical progression scale 4 or greater.

Results

Of 52 randomized participants [median (interquartile range) age, 53.5 (43.3 - 60.0) years; 31 (60.0%) men], 44 (85.0%) completed the trial. Clinical deterioration occurred in 2 of 26 patients in each group (P >0.99). There were no serious adverse events in either group. Clinical deterioration occurred in 15 (6.0%) of 271 patients admitted to the CTC, and all of them were transferred to a hospital. In multivariate analysis, age between 55 and 64, fever and pneumonia at admission were independent risk factors for clinical deterioration.

Conclusion

In this study of adult patients with symptomatic COVID-19 who were admitted to the CTC, there was no significant differences in clinical deterioration between patients treated with fluvoxamine and placebo (ClinicalTrials.gov Identifier: NCT04711863).

Kinetics of Glycoprotein-Specific Antibody Response in Patients with Severe Fever with Thrombocytopenia Syndrome

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tickborne disease in East Asia that is causing high mortality. The Gn glycoprotein of the SFTS virus (SFTSV) has been considered to be an essential target for virus neutralization. However, data on anti-Gn glycoprotein antibody kinetics are limited. Therefore, we investigated the kinetics of Gn-specific antibodies compared to those of nucleocapsid protein (NP)-specific antibodies. A multicenter prospective study was performed in South Korea from January 2018 to September 2021. Adult patients with SFTS were enrolled. Anti-Gn-specific IgM and IgG were measured using an enzyme-linked immunosorbent assay. A total of 111 samples from 34 patients with confirmed SFTS were analyzed. Anti-Gn-specific IgM was detected at days 5–9 and peaked at day 15–19 from symptom onset, whereas the anti-NP-specific IgM titers peaked at days 5–9. Median seroconversion times of both anti-Gn- and NP-specific IgG were 7.0 days. High anti-Gn-specific IgG titers were maintained until 35–39 months after symptom onset. Only one patient lost their anti-Gn-specific antibodies at 41 days after symptom onset. Our data suggested that the anti-Gn-specific IgM titer peaked later than anti-NP-specific IgM, and that anti-Gn-specific IgG remain for at least 3 years from symptom onset.

Comparison of the Clinical Outcomes of Patients With Positive Xpert Carba-R Tests for Carbapenemase-Producing Enterobacterales According to Culture Positivity

Background

We aimed to compare the clinical outcomes of patients with positive Xpert Carba-R assay results for carbapenemase-producing Enterobacterales (CPE) according to CPE culture positivity.

Methods

We retrospectively collected data for patients with positive CPE (positive Xpert Carba-R or culture) who underwent both tests from August 2018 to March 2021 in a 2700-bed tertiary referral hospital in Seoul, South Korea. We compared the clinical outcomes of patients positive for Xpert Carba-R according to whether they were positive (XPCP) or negative (XPCN) for CPE culture.

Results

Of 322 patients with CPE who underwent both Xpert Carba-R and culture, 313 (97%) were positive for Xpert Carba-R for CPE. Of these, 87 (28%) were XPCN, and 226 (72%) were XPCP. XPCN patients were less likely to have a history of previous antibiotic use (75.9% vs 90.3%; P = .001) and to have Klebsiella pneumoniae carbapenemase (21.8% vs 48.9%; P < .001). None of the XPCN patients developed infection from colonization within 6 months, whereas 13.4% (29/216) of the XPCP patients did (P < .001). XPCN patients had lower transmission rates than XPCP patients (3.0% [9/305] vs 6.3% [37/592]; P = .03). There was no significant difference in CPE clearance from positive culture results between XPCN and XPCP patients (40.0% [8/20] vs 26.7% [55/206]; P = .21).

Conclusions

Our study suggests that XPCN patients had lower rates of both infection and transmission than XPCP patients. The Xpert Carba-R assay is clinically useful not only for rapid identification of CPE but also for predicting risks of infection and transmission when performed along with culture.

Optimal duration of antiviral treatment in patients with gastrointestinal cytomegalovirus disease at a low and high risk of relapse

We evaluated the association between antiviral treatment duration and relapse of gastrointestinal (GI) cytomegalovirus (CMV) disease by analyzing the risk factors for relapse.Patients who were diagnosed with GI CMV disease at a tertiary hospital from January 2008 to April 2019 were retrospectively enrolled. Patients with relapsed disease were those with a recurrence of GI CMV disease at least 4 weeks after the initial antiviral treatment.Of 238 participants, including 145 (51.9%) with upper and 93 (48.1%) with lower GI CMV diseases, 27 (11.3%) had experienced relapses. The difference in antiviral treatment duration between the relapsed and nonrelapsed GI CMV groups was not significant (median days, 21.0 vs 17.0, P = .13). Multivariate analysis revealed that hematologic malignancy (odds ratio, 3.73; P = .026) and ulcerative colitis (odds ratio, 4.61; P = .003) were independent risk factors for relapse. Participants with at least one of these risk factors and those with no independent risk factors were classified under the high- (relapse rate, 25.9%) and low-risk of relapse groups (relapse rate, 6.7%), respectively. Accordingly, we further stratified 180 (75.6%) and 58 (24.4%) participants under the low- and high-risk of relapse groups, respectively. There was no significant difference in relapse rates between the high- and low-risk groups according to antiviral treatment duration.Approximately 10% of the participants experienced relapses after antiviral treatment, with hematologic malignancy and ulcerative colitis featuring as risk factors. Therefore, prolonged antiviral treatment might not be helpful in preventing GI CMV disease relapse.

Clinical features of patients with Legionnaires disease showing initial clinical improvement but radiological deterioration: A retrospective single-center analysis

Patients with Legionnaires disease occasionally experience initial clinical improvement but radiological progression. However, data on this issue are so far limited. The aim of this study was to investigate changes in chest radiograph findings in patients with Legionnaires disease who showed initial clinical improvement and to identify risk factors and outcomes in these patients.All patients diagnosed with Legionnaires disease at a tertiary hospital in South Korea between March 2011 and May 2020 were retrospectively enrolled. Legionnaires disease was defined as abnormal chest radiographs accompanied by a positive finding on at least one of the following tests: urinary antigen test, sputum Legionella polymerase chain reaction, and sputum Legionella culture. Clinical improvement was defined as defervescence and decreased C-reactive protein level. Clinical and radiological records were reviewed on treatment days 7 and 14 and at discharge. We describe the characteristics of patients with clinical improvement but radiological deterioration on treatment for Legionnaires disease and compared them with patients with initial clinical improvement and stable or resolving chest radiograph findings.Of 140 patients with Legionnaires disease, 33 (24%) showed initial clinical deterioration, while the remaining 107 (76%) showed initial clinical improvement on day 7. The latter 107 patients were analyzed in this study; 22 (21%) showed radiological progression despite the clinical improvement. Risk factors for these patients were a high pneumonia severity index score and the use of mechanical ventilation. Mortality did not significantly differ between those with initial clinical improvement but radiological deterioration and those with both initial clinical and radiological improvement (28% vs 12%, P = .49).About one-fifth of patients with Legionnaires disease, especially those who had a high pneumonia severity index score and underwent mechanical ventilation, showed radiological deterioration despite of clinical improvement 1 week after appropriate treatment, while outcomes were not significantly worse in these patients. Therefore, our findings support that close monitoring without modification of antibiotics use is warranted in those who have clinical improvement regardless of radiologic findings.

In Vitro Activities of Ceftazidime-Avibactam and Aztreonam-Avibactam at Different Inoculum Sizes of Extended-Spectrum β-Lactam-Resistant Enterobacterales Blood Isolates

β-lactam–avibactam combinations have been proposed as carbapenem-sparing therapies, but little data exist on their in vitro activities in infections with high bacterial inocula. We investigated the in vitro efficacies and the inoculum effects of ceftazidime–avibactam and aztreonam–avibactam against extended-spectrum β-lactam-resistant Enterobacterales blood isolates. A total of 228 non-repetitive extended-spectrum β-lactam-resistant Escherichia coli and Klebsiella pneumoniae blood isolates were prospectively collected in a tertiary center. In vitro susceptibilities to ceftazidime, aztreonam, meropenem, ceftazidime–avibactam, and aztreonam–avibactam were evaluated by broth microdilution method using standard and high inocula. An inoculum effect was defined as an eightfold or greater increase in MIC when tested with the high inoculum. Of the 228 isolates, 99% were susceptible to ceftazidime–avibactam and 99% had low aztreonam–avibactam MICs (≤8 mg/L). Ceftazidime–avibactam and aztreonam–avibactam exhibited good in vitro activities; MIC₅₀/MIC₉₀ values were 0.5/2 mg/L, 0.125/0.5 mg/L, and ≤0.03/0.25 mg/L, respectively, and aztreonam–avibactam was more active than ceftazidime–avibactam. The frequencies of the inoculum effect with ceftazidime–avibactam and aztreonam–avibactam were lower than with meropenem (14% vs. 38%, p < 0.001 and 30% vs. 38%, p = 0.03, respectively). The β-lactam-avibactam combinations could be useful as carbapenem-sparing strategies, and aztreonam–avibactam has the better in vitro activity but is more subject to the inoculum effect than ceftazidime–avibactam.

817. Appropriate Sites for the Active Surveillance of Carbapenemase-producing Enterobacteriaceae

Background

Active surveillance tests for carbapenemase-producing Enterobacteriaceae (CPE) are recommended in patients showing risk factors for colonization by these bacteria. There are limited data however on whether surveillance tests for anatomic sites other than the stool would be useful to detect CPE colonization, and we investigated this in our present study.

Methods

Retrospective analysis was performed on cases at our tertiary care hospital during a 5-year period. The study patients with CPE colonization had been admitted to our surgical intensive care unit (SICU) or sub-ICU for liver transplantation in this period and undergone surveillance tests for both the stool and other sites. Patients were grouped as stool CPE negative (but which included CPE positive cases from initial sputum and other site tests) or positive.

Results

Among the total study cohort of 158 patients, 138 (87.3%) were included in the stool CPE positive group and the remaining 20 (12.7%) in the stool CPE negative group. While the sensitivity of CPE surveillance testing of the stool was 87.3% (95% CI 81.1-92.1), the sensitivity when combining stool and sputum samples was 93.7% (88.7-96.9). The transmission rates were similar for patients showing CPE positivity in the stool, sputum and other sites, at 4.8% (27/557), 4.7% (3/64), and 6.7% (1/15), respectively (p = 0.95).

Conclusion

The sensitivity of CPE detection in a stool sample is suboptimal for ruling out CPE colonization and the transmission rates are similar between stool-positive or -negative cases. Combining surveillance of the stool with other sites may be needed for detecting CPE.

Disclosures

All Authors: No reported disclosures

61. Short- versus prolonged-courses of antimicrobial therapy for patients with uncomplicated Pseudomonas aeruginosa bloodstream infection

Background

The optimal duration of antimicrobial therapy for uncomplicated Pseudomonas aeruginosa bloodstream infection (BSI) is unknown. We compared the outcomes of short and prolonged courses of antimicrobial therapy in adults with uncomplicated pseudomonal BSI.

Methods

All patients with uncomplicated P. aeruginosa BSI admitted at a tertiary-care hospital from May 2016 to September 2020 were included. We compared the rate of recurrent P. aeruginosa infection and 30-day mortality among patients who underwent short (7‒11 days) and prolonged (12‒21 days) courses of antimicrobial therapy using propensity score analysis with the inverse probability of treatment weighting (IPTW) method.

Results

We evaluated 1,477 patients with uncomplicated P. aeruginosa BSI; of them, 290 met the eligibility criteria, including 97 (33%) who underwent short-course therapy (9 [interquartile range (IQR), 8‒11] days) and 193 (67%) who underwent prolonged-course therapy (15 [IQR, 14‒18] days). We found no significant difference in the risk of recurrence or 30-day mortality between the prolonged-course and short-course groups (n=10, 11% vs. n=32, 16%; IPTW-adjusted hazard ratio (HR) 0.61; 95% confidence interval (CI) 0.30−1.24; p=0.17). The recurrence of P. aeruginosa infection at any site within 180 days of completing therapy occurred significantly more in the prolonged-course group (n=10, 10% vs. n=38, 20%; IPTW-adjusted HR 0.48; 95% CI 0.24−0.96, p=0.04). The resistance acquisition in subsequent P. aeruginosa isolates was more frequent in the prolonged-course group, although the difference was not statistically significant (n=2, 20% vs. n=12, 32%; p=0.70).

Conclusion

Short-course antimicrobial therapy could be as effective as prolonged-course therapy for uncomplicated P. aeruginosa bloodstream infection.

Disclosures

All Authors: No reported disclosures

Molecular diagnosis of Coxiella burnetii in culture negative endocarditis and vascular infection in South Korea

BACKGROUND

Q fever endocarditis is a major cause of culture-negative endocarditis. The role of Coxellia burnetii is underestimated because it is difficult to diagnose. We investigated the significance of C. burnetii as the cause of culture-negative endocarditis and vascular infection by examining blood and tissue specimens using serological testing and polymerase chain reaction (PCR).

METHODS

All patients with infective endocarditis or large vessel vasculitis were prospectively enrolled at a tertiary-care hospital from May 2016 through September 2020. Q fever endocarditis and vascular infection were diagnosed based on: (1) positive PCR for a cardiac valve or vascular tissue, (2) positive PCR for blood or phase I immunoglobulin G (IgG) ≥ 6400, or (3) phase I IgG ≥ 800 and < 6400 with morphologic abnormality. PCR targeted C. burnetii transposase gene insertion element IS1111a.

RESULTS

Of the 163 patients, 40 (25%) had culture-negative endocarditis (n = 35) or vascular infection (n = 5). Of the 40 patients, 24 (60%) were enrolled. Eight (33%) were diagnosed with Q fever endocarditis or vascular infection. Of these 8 patients, 6 had suspected acute Q fever endocarditis or vascular infection with negative phase I IgG. Six patients were not treated for C. burnetii, 4 were stable after surgery. One patient died due to surgical site infection after 5 months post-operatively and one died due to worsening underlying disease.

CONCLUSIONS

Approximately one-third of patients with culture-negative endocarditis and vascular infection was diagnosed as Q fever. Q fever endocarditis and vascular infection may be underestimated in routine clinical practice in South Korea.KEY MESSAGEQ fever endocarditis and vascular infection may be underestimated in routine clinical practice, thus, try to find evidence of C. burnetti infection in suspected patients by all available diagnostic tests including PCR.

Viral and Immunologic Factors Associated with Fatal Outcome of Patients with Severe Fever with Thrombocytopenia Syndrome in Korea

Significant progress has been made on the molecular biology of the severe fever with thrombopenia virus (SFTSV); however, many parts of the pathophysiological mechanisms of mortality in SFTS remain unclear. In this study, we investigated virologic and immunologic factors for fatal outcomes of patients with SFTS. We prospectively enrolled SFTS patients admitted from July 2015 to October 2020. Plasma samples were subjected to SFTSV RNA RT-PCR, multiplex microbead immunoassay for 17 cytokines, and IFA assay. A total of 44 SFTS patients were enrolled, including 37 (84.1%) survivors and 7 (15.9%) non-survivors. Non-survivors had a 2.5 times higher plasma SFTSV load than survivors at admission (p < 0.001), and the viral load in non-survivors increased progressively during hospitalization. In addition, non-survivors did not develop adequate anti-SFTSV IgG, whereas survivors exhibited anti-SFTSV IgG during hospitalization. IFN-α, IL-10, IP-10, IFN-γ, IL-6, IL-8, MCP-1, MIP-1α, and G-CSF were significantly elevated in non-survivors compared to survivors and did not revert to normal ranges during hospitalization (p < 0.05). Severe signs of inflammation such as a high plasma concentration of IFN-α, IL-10, IP-10, IFN-γ, IL-6, IL-8, MCP-1, MIP-1α, and G-CSF, poor viral control, and inadequate antibody response during the disease course were associated with mortality in SFTS patients.

Clinical and Microbiological Characteristics of Hospital-Acquired Methicillin-Resistant Staphylococcus aureus Bacteremia Caused by a Community-Associated PVL-Negative Strain

Background

ST72-SCCmecIV, a community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strain in Korea, originated in the community and has been spreading in health care settings. Herein, we describe the clinical and microbiological characteristics of patients with hospital-acquired MRSA bacteremia (MRSAB) caused by community-associated strains.

Methods

We analyzed hospital-acquired MRSAB cases caused by ST72-SCCmecIV using a prospective cohort of patients with SAB in a tertiary hospital in Korea from July 2008 to December 2018. We compared the clinical and microbiological characteristics of ST72-SCCmecIV with ST5-SCCmecII, a representative hospital-associated genotype strain.

Results

Of the 1782 S. aureus bacteremia (SAB) cases, 628 (35.2%) were hospital-acquired MRSAB. Of the 628 isolates, 431 (68.6%) were ST5-SCCmecII and 152 (24.2%) were ST72-SCCmecIV. Patients with ST72-SCCmecIV were younger than those with ST5-SCCmecII and less likely to have a history of recent surgery, antibiotic treatment, nasal MRSA colonization, and central venous catheter placement. Compared with ST5-SCCmecII, ST72-SCCmecIV isolates were more likely to have vancomycin MICs ≤1.0 mg/L (P < .001). Osteoarticular infection as the site of infection (7.2% [11/152] vs 1.4% [6/431]) was more common in patients with ST72-SCCmecIV. There were no significant differences in the rate of recurrence (≤90 days), persistent bacteremia (≥7 days), or 30- and 90-day mortality rates between the 2 groups.

Conclusions

Osteoarticular infections were more prevalent in ST72-SCCmecIV MRSAB. Mortality rates between the ST72-SCCmecIV and ST5-SCCmecII groups were not significantly different.

Dynamics of Viral Shedding and Symptoms in Patients with Asymptomatic or Mild COVID-19

We conducted a prospective cohort study at a community facility designated for the isolation of individuals with asymptomatic or mild COVID-19 between 10 January and 22 February 2021 to investigate the relationship of viral shedding with symptom changes of COVID-19. In total, 89 COVID-19 adult patients (12 asymptomatic, 16 presymptomatic, 61 symptomatic) were enrolled. Symptom scores, the genomic RNA and subgenomic RNA of SARS-CoV-2 from saliva samples with a cell culture were measured. Asymptomatic COVID-19 patients had a similar viral load to symptomatic patients during the early course of the disease, but exhibited a rapid decrease in viral load with the loss of infectivity. Subgenomic RNA and viable virus by cell culture in asymptomatic patients were detected only until 3 days after diagnosis, and the positivity of the subgenomic RNA and cell culture in symptomatic patients gradually decreased in both from 40% in the early disease course to 13% at 10 days and 4% at 8 days after the symptom onset, respectively. In conclusion, symptomatic patients have a high infectivity with high symptom scores during the early disease course and gradually lose infectivity depending on the symptom. Conversely, asymptomatic patients exhibit a rapid decrease in viral load with the loss of infectivity, despite a similar viral load during the early disease course.

Risk Factors for Mortality in Patients with Klebsiella pneumoniae Carbapenemase-producing K. pneumoniae and Escherichia coli bacteremia

Background

Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales bacteremia is associated with significant mortality; however, no optimal antibiotic strategy is available. We aimed to evaluate the clinical outcomes according to the antibiotic regimens and identify risk factors for mortality in patients with KPC-producing K. pneumoniae and Escherichia coli bacteremia.

Materials and Methods

This retrospective cohort study included all adult patients with monomicrobial bacteremia (KPC-producing K. pneumoniae or E. coli) between January 2011 and March 2021 at a 2,700-bed tertiary center.

Results

Ninety-two patients were identified; 7 with E. coli bacteremia, and 85 with K. pneumoniae bacteremia. Thirty-day mortality was 38.0% (35/92). Non-survivors were more likely to have had nosocomial infection (88.6% vs. 63.2%, P = 0.01), high APACHE II scores (mean [interquartile range], 22.0 [14.0 - 28.0] vs. 14.0 [11.0 - 20.5], P <0.001), and septic shock (51.4% vs. 26.3%, P <0.001) and less likely to have been admitted to the surgical ward (5.7% vs. 22.8%, P = 0.04), undergone removal of eradicable foci (61.5% vs. 90.6%, P = 0.03), and received appropriate combination treatment (57.1% vs. 78.9%, P = 0.03) than survivors. No significant difference in mortality was observed according to combination regimens including colistin, aminoglycoside, and tigecycline. In multivariable analysis, high APACHE II scores (adjusted odds ratio [aOR], 1.14; 95% confidence interval [CI], 1.06 - 1.23, P <0.001), and appropriate definitive treatment (aOR, 0.25; CI, 0.08 - 0.74, P = 0.01) were independent risk factors for mortality.

Conclusion

High APACHE II scores and not receiving appropriate definitive treatment were associated with 30-day mortality. Mortality did not significantly differ according to combination regimens with conventional drugs such as aminoglycoside and colistin.

Short versus prolonged courses of antimicrobial therapy for patients with uncomplicated Pseudomonas aeruginosa bloodstream infection: a retrospective study

BACKGROUND

The optimal duration of antimicrobial therapy for uncomplicated Pseudomonas aeruginosa bloodstream infection (BSI) is unknown. We compared the outcomes of short and prolonged courses of antimicrobial therapy in adults with uncomplicated pseudomonal BSI.

METHODS

All patients with uncomplicated P. aeruginosa BSI admitted at a tertiary-care hospital from April 2010 to April 2020 were included. We compared the primary outcome (a composite of the rate of recurrent P. aeruginosa infection and mortality within 30 days after discontinuing antimicrobial therapy) among patients who underwent short (7‒11 days) and prolonged (12‒21 days) courses of antimicrobial therapy using propensity score analysis with the inverse probability of treatment weighting (IPTW) method.

RESULTS

We evaluated 1477 patients with P. aeruginosa BSI; of them, 290 met the eligibility criteria who received antimicrobial agents with in vitro activity, including 97 (33%) who underwent short-course therapy [median of 9 (IQR = 8‒11) days] and 193 (67%) who underwent prolonged-course therapy [median of 15 (IQR = 14‒18) days]. We found no significant difference in the risk of recurrence or 30 day mortality between the prolonged-course and short-course groups [n = 30 (16%) versus n = 11 (11%); IPTW-adjusted HR = 0.68, 95% CI = 0.34 - 1.36, P = 0.28]. The prolonged-course therapy did not significantly reduce the risk of the recurrence of P. aeruginosa infection within 180 days compared with short-course therapy [n = 37 (19%) versus n = 12 (12%); IPTW-adjusted HR = 0.57, 95% CI = 0.29 - 1.10, P = 0.09].

CONCLUSIONS

Short-course antimicrobial therapy could be as effective as prolonged-course therapy for uncomplicated P. aeruginosa BSI.

Risk of tuberculosis in patients with cancer treated with immune checkpoint inhibitors: a nationwide observational study

BACKGROUND

While some recent studies have reported the development of tuberculosis (TB) in patients exposed to immune checkpoint inhibitors (ICIs), there is limited evidence to date. Therefore, we evaluated the risk of TB in patients with cancer exposed to ICIs using the National Health Insurance claims data in South Korea.

METHODS

Patients with diagnostic codes for non-small cell lung cancer, urothelial carcinoma or melanoma between August 2017 and June 2019 were identified. The incidence rate and standardized incidence ratio (SIR) of TB were calculated for both the ICI exposure and non-exposure groups. The risk of TB according to ICI exposure was assessed using a multivariable Cox regression model.

RESULTS

During the study period, 141 550 patients with cancer and 916 new TB cases were identified. Among the 5037 patients exposed to ICIs, 20 were diagnosed with TB at a median of 2.2 months after the ICI was initiated. The crude incidence rate of TB per 100,000 person-years was 675.8 (95% CI 412.8 to 1043.8) for the ICI exposure group and 599.1 (95% CI 560.5 to 639.6) for the non-exposure group. The SIR for TB was 8.1 (95% CI 8.0 to 8.2) in the ICI exposure group. After adjusting for potential confounding factors, ICI treatment was not significantly associated with an increased risk of TB (HR: 0.73; 95% CI 0.47 to 1.14).

CONCLUSIONS

While the incidence of TB in cancer patients exposed to ICIs was eightfold higher than in the general population, the risk of patients with cancer developing TB did not significantly differ according to ICI exposure.

Comparison of the characteristics of patients with invasive infections and noninvasive infections caused by Trichosporon asahii

We performed retrospective study to identify the characteristics of invasive Trichosporon asahii infection. A total of 102 patients with T. asahii were identified including 18 (18%) with invasive infection. Invasive infection was associated with indwelling central venous catheter (94% vs 54%, P = .001), prior antifungal agent use (50% vs 18%, P = .01), hematologic malignancy (33% vs 7%, P = .006), and end-stage renal disease (28% vs 7%, P = .02). Patients with invasive infections had higher in-hospital mortality than patients with noninvasive infections (61% vs 27%, P = .006). Those with the above risk factors should be monitored for the development of invasive T. asahii infection.

LAY SUMMARY

Patients with indwelling central venous catheter, prior antifungal agent use, hematologic malignancy, and end-stage renal disease were associated with invasive Trichosporon asahii infection. Patients with invasive infections had higher in-hospital mortality than patients without invasive infection.

Changing characteristics of S. aureus bacteremia caused by PVL-negative, MRSA strain over 11 years

Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) has emerged as an important cause of infection. We conducted a longitudinal study to evaluate changes in clinical and microbiological characteristics as well as outcomes of sequence type (ST) 72 MRSA bacteremia. We reviewed adult patients enrolled in a prospective cohort with ST72 MRSA bacteremia from August 2008 to December 2018 at Asan Medical Center, Seoul, South Korea. Changes in clinical characteristics, outcomes, and microbiological characteristics of patients over time were evaluated. Generalized linear and linear regression models were used to evaluate changes. Of the 1,760 isolates, 915 (62%) were MRSA bacteremia and 292 (31.9%) were ST72 MRSA. During the study period, the relative risk (RR) of MRSA bacteremia decreased annually by 3.7%; however, among MRSA bacteremia, RR of ST72 MRSA increased annually by 8.5%. Vancomycin minimum inhibitory concentration (MIC) decreased over the study period. Metastatic infection, persistent bacteremia, and recurrence of bacteremia within 12 weeks decreased significantly. There were no significant changes in 30-d and 12-week mortality. Antibiotic susceptibility of ST72 MRSA was evaluated, and the resistance rate to erythromycin decreased significantly. ST72 MRSA incidence increased annually; its vancomycin MIC and erythromycin resistance rate decreased over the 11 years.

Comparison of clinical outcomes of patients infected with KPC- and NDM-producing Enterobacterales: a retrospective cohort study

OBJECTIVES

We aimed to compare clinical outcomes of patients with Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales and those with New Delhi metallo-β-lactamase (NDM)-producing Enterobacterales.

METHODS

We performed a retrospective cohort study of all adult patients with KPC- or NDM-producing Enterobacterales isolates in a 2700-bed tertiary referral hospital in Seoul, South Korea, between 2010 and 2019. The primary outcome was 30-day mortality after first isolation of KPC- or NDM-producing Enterobacterales. The secondary outcome was the development of infection within 30 days by the colonizing isolates, among colonized patients. We performed Cox regression analysis for 30-day mortality and competing risk analysis for development of infection.

RESULTS

A total of 859 patients were identified during the study period; 475 (55%) had KPC and 384 (45%) had NDM. Thirty-day mortality was significantly higher in the KPC group than in the NDM group (17% (81/475) vs 9% (33/384); p < 0.001). The KPC group developed infection within 30 days from the initial colonization after first isolation more frequently than the NDM group (8% (27/353) vs. 3% (10/295); p 0.02). Multivariable analysis revealed that independent risk factors for 30-day mortality were solid cancer (adjusted hazard ratio (aHR) 2.51; 95% confidence interval (CI) 1.66-3.79; p < 0.001), solid organ transplant (aHR 0.32; 95% CI 0.17-0.61; p < 0.001), a high APACHE II score (aHR 1.11; 95% CI 1.08-1.13; p < 0.001), KPC-producing Enterobacterales (aHR 1.69; 95% CI 1.02-2.79; p 0.04), previous carbapenem use within 3 months (aHR 1.86; 95% CI 1.26-2.75; p < 0.001) and site of KPC- or NDM-producing Enterobacterales infection at the time of the first culture (p < 0.001).

DISCUSSION

Our study suggests that KPC-producing Enterobacterales is significantly associated with poorer outcomes than NDM-producing Enterobacterales.