Eun-Jeong Joo

Impact of de-escalation therapy on clinical outcomes for intensive care unit-acquired pneumonia

IntroductionDe-escalation therapy is a strategy currently used for the management of nosocomial pneumonia. In this study, we evaluated clinical outcomes and risk factors related to de-escalation therapy in patients with intensive care unit (ICU)-acquired pneumonia.MethodsThis was a retrospective observational cohort study of ICU patients who developed pneumonia more than 48 hours after admission to the ICU at Samsung Medical Center from September 2004 to December 2007.ResultsThe 137 patients comprised 44 (32.1%) who received de-escalation therapy and 93 in the non-de-escalation group. The de-escalation group showed a lower pneumonia-related mortality rate than the non-de-escalation group by day 14 (2.3% vs. 10.8%, respectively; P = 0.08) and by day 30 (2.3% vs. 14%, respectively; P = 0.03) after the diagnosis of pneumonia. The variables independently associated with ICU-acquired pneumonia-related mortality included the Acute Physiology and Chronic Health Evaluation II (APACHE II) score and the modified Clinical Pulmonary Infection Score (CPIS) after 5 days with pneumonia. The non-de-escalation group had significantly higher APACHE II score and modified CPIS after 5 days with ICU-acquired pneumonia compared to the de-escalation group. Among all patients, 20.4% (28 of 137) had negative cultures for pathogens, and 42.9% (12 of 28) received de-escalation therapy. The latter 12 patients received de-escalation therapy and survived 30 days after the diagnosis of pneumonia.ConclusionsPatients in the de-escalation group showed a significantly lower mortality rate compared to patients in the non-de-escalation group. De-escalation therapy can be safely provided to patients with ICU-acquired pneumonia if they are clinically stable by day 5, even in those whose respiratory specimen cultures yield no specific pathogens.

Risk factors for mortality in patients with Pseudomonas aeruginosa bacteremia: clinical impact of antimicrobial resistance on outcome.

Despite the high prevalence of antimicrobial resistance among Pseudomonas aeruginosa bacteremia, the clinical consequence of resistance remains unclear. The purpose of this study was to identify predictors of mortality and evaluate the clinical impact of antimicrobial resistance on outcome in P. aeruginosa bacteremia. A retrospective cohort study including patients with P. aeruginosa bacteremia was performed. The risk factors for antimicrobial resistances were evaluated, and the impact of the respective resistances on mortality was assessed. Of 202 P. aeruginosa bacteremia cases, the resistance rates to ceftazidime, piperacillin, imipenem, fluoroquinolone, and aminoglycoside were 36.6%, 22.3%, 22.8%, 23.8%, and 17.8%, respectively. A prior use of fluoroquinolones and an indwelling urinary catheter were common risk factors for all types of antimicrobial resistance. The overall 30-day mortality rate was 25.2% (51/202), and the risk factors for mortality were corticosteroid use, nosocomial acquisition, polymicrobial infection, an increasing Charlsons weighted co-morbidity index, and intensive care unit care (pu2009<u20090.05). As compared with the susceptible group, ceftazidime-, piperacillin-, or imipenem-resistant groups had a higher mortality (pu2009<u20090.05). A multivariate analysis showed that resistance to ceftazidime or imipenem remained a significant factor associated with mortality (odds ratio, 2.96; 95% confidential interval, 1.20-7.31; and odds ratio, 2.74; 95% confidential interval, 1.02-7.31, respectively). Antimicrobial resistance, especially to ceftazidime or imipenem, adversely affected outcome in patients with P. aeruginosa bacteremia.

Duration of colonization and risk factors for prolonged carriage of vancomycin-resistant enterococci after discharge from the hospital

BACKGROUNDnThere are no available studies on the duration and risk factors of vancomycin-resistant enterococci (VRE) carriage after hospital discharge. In this study we investigated the duration of colonization with VRE and the risk factors for prolonged carriage in the outpatient clinic after discharge from the hospital.nnnMETHODSnThe study took place from January 2008 to September 2009. Patients were included if they were identified as persistent VRE carriers by follow-up rectal swab or stool cultures in the outpatient setting, after discharge from the hospital without clearance of VRE. The probability of culture positivity and clearance was analyzed from the discharge date. Cox regression was performed to determine the risk factors for prolonged carriage. VRE clearance was defined as VRE-negative rectal (or stool) cultures on at least three consecutive occasions a minimum of 1 week apart.nnnRESULTSnOne hundred twenty-seven patients were included in this study. Follow-up cultures were conducted for a median of 8.86 weeks (range 1-90 weeks) after hospital discharge. The median duration of culture positivity of VRE was 5.57 weeks (range 0-50.14 weeks). Ninety-six out of 127 patients (75.6%) showed the first negative culture result at a median time of 4.86 weeks (range 0-66 weeks) after discharge. Among these patients, 15 were lost to follow-up after the first negative culture and eight were lost after the second negative culture. Sixty-eight patients (53.5%) were confirmed to have clearance of VRE during follow-up in the outpatient clinic. The median time to clearance after discharge was 8.86 weeks (range 2-90 weeks). In the cleared cases, the median time to the first negative VRE culture result was 4.71 weeks (range 0-66 weeks). Ninety percent of patients showed the first negative culture result at 25 weeks and VRE clearance at 30 weeks after discharge. Surgery or antibiotic use during admission (p = 0.048 and p = 0.001, respectively), dialysis (p = 0.046), and discharge to a nursing home or other health care institution (p = 0.025) were independently associated with prolonged colonization with VRE.nnnCONCLUSIONSnThe median duration of VRE colonization was 5.57 weeks after hospital discharge. In the cases with clearance during follow-up, the median time to clearance after discharge was 8.86 weeks. Risk factors for prolonged carriage were surgery, antibiotic use during admission, dialysis, and discharge to a nursing home or other health care institution. Therefore, patients with these risk factors should be managed more carefully to prevent transmission of VRE in the outpatient clinic.

Impact of inappropriate empiric antimicrobial therapy on outcome in Pseudomonas aeruginosa bacteraemia: a stratified analysis according to sites of infection

BackgroundThe purpose of this study was to evaluate the impact of inappropriate empiric antimicrobial therapy on the outcome of Pseudomonas aeruginosa bacteraemia according to the primary infection site.MethodsA retrospective cohort study including 202 patients with P. aeruginosa bacteraemia was performed. High-risk sites of infection were defined as the lung, intra-abdominal non-hepatobiliary tract or unknown source.ResultsOf the 202 patients with P. aeruginosa bacteraemia, 80 (39.6%) had received inappropriate empiric antimicrobial therapy. No significant difference in the 30-day mortality rate was found between the inappropriate therapy group and the appropriate therapy group (19/80 [23.8%] vs. 32/122 [26.2%], Pxa0=xa00.692). Patients with pneumonia or non-hepatobiliary tract intra-abdominal infection showed significant association with high mortality, while those with urinary tract or hepatobiliary tract infection showed negative associations with mortality. In the subgroup analysis including 98 patients with high-risk sites of infection, the mortality rate of the inappropriate therapy group was significantly higher than that of the appropriate therapy group (14/26 [53.8%] vs. 23/72 [31.9%], Pxa0=xa00.035). Inappropriate empiric antimicrobial therapy was also found to be one of the independent risk factors for mortality in patients with high-risk sites of infection (odds ratio [OR] 8.69; 95% confidence interval [CI] 1.86–40.59), along with renal disease, corticosteroid use, polymicrobial infection and higher Pitt bacteraemia score.ConclusionInappropriate empiric antimicrobial therapy adversely affected the outcome of P. aeruginosa bacteraemia in patients with high-risk sites of infection. Our data suggest that the impact of inappropriate antimicrobial therapy on the outcome of P. aeruginosa bacteraemia may be dependent on the primary site of infection.

Community-associated Panton–Valentine leukocidin-negative meticillin-resistant Staphylococcus aureus clone (ST72-MRSA-IV) causing healthcare-associated pneumonia and surgical site infection in Korea

BACKGROUNDnCommunity-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) has emerged as an important pathogen worldwide in a continent-specific manner. Clinical characteristics of infections caused by CA-MRSA other than USA300, especially in healthcare settings, have not been well established.nnnAIMnTo conduct a retrospective cohort study to determine the clinical characteristics of infections caused by Panton-Valentine leukocidin (PVL)-negative, multilocus sequence type (ST) 72 staphylococcal cassette chromosome mec (SCCmec) type IV, a major CA-MRSA clone in Korea.nnnMETHODSnST72-IV isolates, which were susceptible to fluoroquinolones, gentamicin, rifampicin, and cotrimoxazole, were presumptively identified among 4667 MRSA isolates and then confirmed by SCCmec typing and multilocus sequence typing. A total of 124 cases of ST72-IV infections were analysed.nnnFINDINGSnThe annual incidence of infections by ST72-IV per 100,000 admissions increased from 45.5 to 66.3 cases during 2007-2009. The most frequently occurring type of infection was skin and soft tissue infection (SSTI) (46.0%), followed by pneumonia (27.4%) and bone and joint infection (9.7%). Surgical site infection accounted for 22.6% and 32.5% of community-onset (CO) healthcare-associated infection and hospital-onset (HO) infection, respectively. Pneumonia was most frequent (45.0%) among HO infection. Multivariate analysis showed that pneumonia increased the odds of all-cause mortality (odds ratio: 18.8; 95% confidence interval: 2.6-133.9) compared with other types of infection.nnnCONCLUSIONSnIncreasing trends were observed in annual incidence of CO and HO infections by ST72-IV in Korea. Pneumonia was the most frequent among HO infection and was associated with higher mortality. These findings pose important implications for successful antibiotic therapy and infection control in the era of CA-MRSA.

Clinical implications of healthcare-associated infection in patients with community-onset acute pyelonephritis

Abstract Background: Clinical and microbiological characteristics of healthcare-associated acute pyelonephritis (HCA-APN) have not been described in detail yet. We sought to delineate the differences between community-associated (CA)- and HCA-APN with specific interest in antibiotic resistance of causative microorganisms. Methods: We conducted a retrospective cohort study during a 1-y period at a large referral center. Patients who visited the emergency department with symptoms and signs of APN were included in the study population. Results: Among 319 cases with community-onset APN, 201 cases (63%) were classified as HCA-APN. Patients with HCA-APN had higher SOFA (sequential organ failure assessment) scores, longer length of hospital stay and a lower rate of complete response to antimicrobial therapy. Patients with complicated APN also had characteristics similar to those seen in HCA-APN. However, 14-day mortality rates were not different between CA-APN vs HCA-APN and between uncomplicated APN vs complicated APN. With regard to microbiological characteristics, Escherichia coli were less common in HCA-APN than in CA-APN (62.7% vs 93.2%, p < 0.001). Among E. coli isolates, quinolone resistance and extended-spectrum beta-lactamase (ESBL) production were more common in HCA-APN than in CA-APN (38.9% vs 12.7%, p < 0.001; 15.9% vs 0.8%, p < 0.001, respectively). Conclusions: HCA-APN, and complicated APN, represents a distinct subset of urinary tract infections with more antibiotic-resistant pathogens and worse outcomes, which physicians should consider to provide optimal treatment.

Epidemiology and Clinical Features of Community-Onset Bacteremia Caused by Extended-Spectrum β-Lactamase–Producing Klebsiella pneumoniae

There is limited clinical information regarding community-onset bacteremia caused by extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae. This study was performed to evaluate risk factors and clinical outcomes of community-onset bacteremia caused by ESBL-producing K. pneumoniae. A total of 435 patients with community-onset K. pneumoniae bacteremia were included and data from patients with ESBL-producing K. pneumoniae bacteremia were compared to those with non-ESBL-producing bacteremia. Isolates with ESBLs were microbiologically characterized. Of 435 patients with community-onset K. pneumoniae bacteremia, 33 (7.6%) were infected with ESBL producers, of which 25 were further classified as healthcare-associated infections. The most common underlying diseases were solid tumors (nu2009=u200920, 60.6%) and diabetes mellitus (nu2009=u200910, 30.3%), and the most common infection was intra-abdominal infection (nu2009=u200920, 60.6%). Multivariate analysis showed that corticosteroid use (odds ratio [OR]u2009=u200913.73, 95% confidence interval [CI]u2009=u20091.93-97.6, pu2009=u20090.009), percutaneous tubes (ORu2009=u20097.30, 95% CIu2009=u20092.41-22.12, pu2009<u20090.001), and prior receipt of antibiotics (ORu2009=u20095.65, 95% CIu2009=u20092.43-14.16, pu2009<u20090.001) were significant factors associated with ESBL producers. When the 30-day mortality rate was evaluated, no significant difference was found between ESBL group and non-ESBL group (12.1% [4/32] vs. 16.0% [35/192]; pu2009=u20090.429). Among 16 isolates, for which the ESBL characterization was performed by PCR, the most common types of ESBLs were SHV (nu2009=u200916) and cefotaxime-M-2 (nu2009=u20095). Pulsed-field gel electrophoresis analysis of the ESBL-producing organisms showed extensive clonal diversity. ESBL-producing K. pneumoniae is a significant cause of bacteremia, even in patients with community-onset infections, particularly in patients with corticosteroid use, percutaneous tube, prior receipt of antibiotics, or healthcare-associated infections.

Tacrolimus as a risk factor for tuberculosis and outcome of treatment with rifampicin in solid organ transplant recipients.

The purpose of this study was to investigate the incidence, risk factors, and treatment outcome of tuberculosis (TB) in solid organ transplant (SOT) recipients treated with rifampicin.

High vancomycin minimum inhibitory concentration is a predictor of mortality in meticillin-resistant Staphylococcus aureus bacteraemia.

Failure of vancomycin in the treatment of meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia has been reported despite full susceptibility of the organism to vancomycin. A retrospective observational cohort study including 137 patients with MRSA bacteraemia was performed at two centres in South Korea during 2009-2010. A total of 137 patients with MRSA bacteraemia receiving vancomycin therapy were enrolled during the study period. Isolates from 13 (9.5%) of the 137 patients had minimum inhibitory concentrations (MICs) ≥1 μg/mL. The 30-day cumulative survival was 53.8% for patients infected with isolates having a MIC≥1 μg/mL and 79.8% for patients infected with isolates having a MIC<1 μg/mL (log-rank test, P=0.026). Vancomycin MIC≥1 μg/mL [hazard ratio (HR)=7.0, 95% confidence interval (CI) 2.2-22.1; P=0.001], nosocomial acquisition of bacteraemia (HR=5.4, 95% CI 1.4-20.1; P=0.013), rapidly fatal underlying diseases (HR=20.5, 95% CI 3.9-106.4; P<0.001), presentation with septic shock (HR=8.4, 95% CI 3.0-23.3; P<0.001), presence of complicated infections (HR=5.6, 95% CI 2.0-15.8; P=0.001) and persistent MRSA bacteraemia for ≥3 days (HR=4.2, 95% CI 1.4-12.7; P=0.012) were independent predictors of 30-day mortality in patients with MRSA bacteraemia. In patients with high Pitt bacteraemia scores (Pitt score ≥2), the delay in initiation of vancomycin therapy was significantly different between non-survivors and survivors (2.4 days vs. 1.1 days; P=0.012). Vancomycin MIC≥1 μg/mL had a significant impact on mortality of patients with MRSA bacteraemia. These findings support early consideration of alternative anti-MRSA agents in patients with MRSA bacteraemia who have high vancomycin MICs as well as prompt initiation of anti-MRSA treatment in patients with MRSA bacteraemia, especially those with high Pitt scores.

Post-influenza Pneumonia Caused by the USA300 Community-Associated Methicillin-Resistant Staphylococcus aureus in Korea

Panton-Valentine leukocidin (PVL)-positive USA300 clone has been the most successful community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) clone spreading in North America. In contrast, PVL-negative ST72-CA-MRSA has been predominant in Korea, and there has been no report of infections by the USA300 strain except only one case report of perianal infection. Here, we describe the first case of pneumonia caused by the USA300 strain following pandemic influenza A (H1N1) in Korea. A 50-year-old man was admitted with fever and cough and chest radiograph showed pneumonic consolidation at the right lower lung zone. He received a ventilator support because of respiratory failure. PCR for pandemic influenza A (H1N1) in nasopharyngeal swab was positive, and culture of sputum and endotracheal aspirate grew MRSA. Typing of the isolate revealed that it was PVL-positive, ST 8-MRSA-SCCmec type IV. The analysis of the PFGE patterns showed that this isolate was the same pulsotype as the USA300 strain.