Ji-Young Rhee

Scoring systems for prediction of mortality in patients with intensive care unit-acquired sepsis: a comparison of the Pitt bacteremia score and the Acute Physiology and Chronic Health Evaluation II scoring systems.

This study compares the effectiveness of the Pitt bacteremia score, the Charlson weighted index of comorbidity, and the Acute Physiology and Chronic Health Evaluation II (APACHE II) scoring systems for the prediction of mortality in intensive care unit (ICU) patients with sepsis using the retrospective observational method on 134 patients with ICU-acquired sepsis. The statistical analyses show several important findings. First, Pitt bacteremia score is significantly correlated with the APACHE II scoring system (correlation coefficient = 0.738, P < 0.001). Second, the APACHE II scoring system, the Pitt bacteremia score, and the Charlson weighted index of comorbidity are independently correlated with mortality. Third, the Pitt bacteremia score and the APACHE II scores are positively related to mortality in patients with ICU-acquired sepsis. As the result of the analyses, the mortality rate in patients with sepsis in the ICU is better predicted with the Pitt bacteremia score because it provides better estimation of sensitivity and specificity than the APACHE II scoring system and the Charlson weighted index of comorbidity.

KPC-Producing Extreme Drug-Resistant Klebsiella pneumoniae Isolate from a Patient with Diabetes Mellitus and Chronic Renal Failure on Hemodialysis in South Korea

The prevalence of extended-spectrum β-lactamases (ESBLs) has limited the available therapeutic options and necessitated the increased use of carbapenems against Klebsiella pneumoniae infections. In response to use of carbapenems, carbapenem resistance has developed and flourished. In 1996, a new β-lactamase termed “K. pneumoniae carbapenemase” (KPC) was reported in New York, NY (12). Subsequently, KPC-producing K. pneumoniae has been spread worldwide (9). However, it has not hitherto been reported in South Korea. We report a case of infection with a KPC-producing extreme drug-resistant (XDR) K. pneumoniae isolate in a tertiary care hospital in South Korea. A 65-year-old male patient who had diabetes mellitus and chronic renal failure on hemodialysis visited the emergency room because of persistent watery diarrhea. Upon admission, blood pressure was 80/55 mm Hg and body temperature was 37.8°C. Blood pressure became 100/65 mm Hg after a massive fluid administration. Sigmoidoscopy showed whitish dirty mucous membrane, compatible with pseudomembranous colitis. The patient was admitted to the intensive care unit under the diagnosis of sepsis due to pseudomembranous colitis. The patient received oral vancomycin because of refractoriness of metronidazole. On postadmission day 7, the patient exhibited vomiting and chest pain. An electrocardiogram and blood work revealed an acute myocardial infarction and ventricular tachycardia. An emergency angiography was performed uneventfully. Postoperatively, the patient displayed purulent sputum, tachypnea, and fever up to 39.5°C. A chest radiogram revealed infiltration on the right lower lobe. Meropenem was initiated to treat the hospital-acquired pneumonia. Six days later, a chest radiogram revealed expansion of the infiltration to the middle and upper lobes. The patient displayed a fever of 39.2°C and blood pressure of 70/40 mm Hg. The patient was treated as for septic shock with a mechanical ventilator, inotropics, and administration of broad-spectrum antibiotics including vancomycin and colistin. Gram stain of bronchial aspirates revealed one to three Gram-negative organisms per high-power field. The patients condition did not improve, and he was discharged with a poor prognosis. During hospitalization, antimicrobial susceptibility testing was performed by a broth microdilution method according to CLSI guidelines (3). The isolate, Kpn-DK2, was nonsusceptible to all antimicrobial agents tested (Table ​(Table1)1) and displayed intermediate resistance even to tigecyline (MIC of 4 mg/liter). The isolate could be defined as XDR (11). Kpn-DK2 was ESBL positive (3) but metallo-β-lactamase (MBL) negative (2). Kpn-DK2 was positive for blaTEM, blaSHV, and blaCTX-M but was negative for blaCMY, blaP99, blaVIM, blaIMP, and blaACT (5, 7) As a result of sequencing, Kpn-DK2 was proven to contain blaCTX-M-15 as an ESBL gene, and blaTEM-1 and blaSHV-11 were also evident. In addition, blaKPC-2 was also present, which is the first detection in South Korea. TABLE 1. Antimicrobial resistance of K. pneumoniae isolate Kpn-DK2 To investigate the genotype of Kpn-DK2, multilocus sequence typing (MLST) was performed as described previously (4), which revealed ST11. MLST has demonstrated that many KPC-producing K. pneumoniae isolates belong to ST258 (1, 6, 8, 10). Although ST11 KPC-producing K. pneumoniae isolates have not been previously reported, to our knowledge, ST258 and ST11 are single locus variants of each other that differ in the tonB allele, and both are widespread clonal groups. Notably, ST11 is the most common clone of ESBL-producing K. pneumoniae isolates in South Korea (unpublished data). Despite lack of evidence of the spread of KPC-producing isolates, it is worrisome that a KPC-producing K. pneumoniae isolate has been found in a common ESBL-producing clone in South Korea.

Characterization of Staphylococcus aureus nasal carriage from children attending an outpatient clinic in Seoul, Korea.

Nasal swabs were collected to isolate S. aureus in 296 children, who visited the pediatrics department with a variety of symptoms. Staphylococcus aureus was isolated from 95 children (32.1%). Of the isolates, 18 were methicillin-resistant S. aureus (MRSA) (18.9%). Antimicrobial susceptibility testing was performed for all S. aureus cultured and the molecular characteristics were investigated. Forty-nine spa types were identified among the S. aureus isolates, and were classified into 13 spa groups (A-L). The most prevalent clone (34 isolates, 35.8%) belonged to the spa group B (spa repeat motif, WG/FKAOMQ), which corresponded to sequence type 30 (ST30) and its variants. Sixteen different spa types, within the spa group B, suggested that this group has evolved over a long period of time. In addition, all S. aureus isolates belonging to the spa group B were methicillin-susceptible, indicating that this group might represent successful adaptation of this clone in the community setting with low antibiotic pressure. The most frequently found clone in the MRSA group was spa group C (spa repeat motif, DMGGM) and SCCmec type IVA, which represented half of the MRSA isolates and corresponded to ST72. ST5-MRSA-II, the most prevalent MRSA clone in Korean hospitals, was found in only two isolates. These findings suggest that strains of S. aureus nasal carriage in Korean children visiting an outpatient pediatric department were different from the strains identified in hospital infections.

Impact of inappropriate antimicrobial therapy on outcome in patients with hospital-acquired pneumonia caused by Acinetobacter baumannii.

OBJECTIVES The purpose of this study was to evaluate the impact of inappropriate antimicrobial therapy on the outcome of patients with hospital-acquired pneumonia (HAP) caused by Acinetobacter baumannii. METHODS All cases of HAP caused by A. baumannii from January 2000 to March 2006 at the Samsung Medical Center (Seoul, Korea) were analyzed retrospectively. RESULTS A total of 116 patients with clinically significant Acinetobacter HAP were enrolled. Among the A. baumannii isolates, 60.3% showed multi-drug resistance (MDR), 16.4% were found to have imipenem resistance, and 15.5% had pan-drug resistance (PDR). The mean APACHE II score of the patients was 22.3 +/- 7.9. The overall in-hospital and pneumonia-related mortality rates were 47.4% and 37.9%, respectively. The univariate analysis showed that the factors associated with pneumonia-related mortality were: MDR, PDR, high APACHE II score, inappropriate empirical antimicrobial therapy, and inappropriate definitive antimicrobial treatment (All p < 0.05). Among these, a high APACHE II score and inappropriate definitive antimicrobial therapy were found to be independent factors associated with a high mortality, after adjustment for other variables. CONCLUSIONS The appropriate definitive antimicrobial therapy should be provided in patients with HAP caused by A. baumannii.

The Fifth Outbreak of Trichinosis in Korea

Trichinosis is a food-borne zoonotic disease caused by the nematode, Trichinella spp., and had been reported several times in Korea. Recently, there was an additional outbreak, involving 5 patients, the findings from which are reported herein. On 30 November 2010, 8 persons ate sashimi of the meat of a wild boar. Then, 2-3 weeks later, they complained of myalgia and fever. Unfortunately, muscle biopsy was not performed, but ELISA was performed using their sera. Two people among 8 were positive for Trichinella on the 34th day post-infection (PI), and 3 patients who initially revealed negative ELISA were additionally proved to be positive for trichinosis on the 42nd day PI. Hence, the confirmed patients of trichinosis were 5 in total in the present outbreak. They were treated with albendazole and discharged uneventfully. This was the fifth outbreak of trichinosis in Korea.

Spontaneous Bacterial Peritonitis due to Ochrobactrum anthropi : A Case Report

We report a case of spontaneous bacterial peritonitis from Ochrobactrum anthropi. O. anthropi is recognized as an emerging pathogen in immunocompromised patients. In contrast to most previously described cases, the patient reported here had no indwelling catheter. To our knowledge, no case of O. anthropi spontaneous bacterial peritonitis has been reported in the medical literature until now.

Distinct groups and antimicrobial resistance of clinical Stenotrophomonas maltophilia complex isolates from Korea.

One hundred and twenty-one isolates of Stenotrophomonas maltophilia complex were collected from seven Korean hospitals. Species and groups were identified using partial gyrB gene sequences and antimicrobial susceptibility testing was performed using a broth microdilution method. Based on partial gyrB gene sequences, 118 isolates were identified as belonging to S. maltophilia complex, including S. maltophilia, S. pavanii, Pseudomonas beteli, P. geniculata and P. hibisciola. The S. maltophilia isolates were further divided into three groups, I to III. S. maltophilia groups II and III were clustered into clade A with S. pavanii and P. beteli; S. maltophilia group I was clustered into clade B with P. geniculata and P. hibisciola. For all S. maltophilia complex isolates, the resistance rate to trimethoprim/sulfamethoxazole (TMP/SMX) was very high (30.5%). Antimicrobial resistance rates varied among species or groups of S. maltophilia complex. Isolates of clade A showed significantly lower antimicrobial resistance rates than those of clade B; while 25% of clade A isolates were multidrug resistant, 46% of clade B isolates were multidrug resistant (P=0.001). The finding of high antimicrobial resistance rates, particularly to TMP/SMX, among S. maltophilia complex isolates from Korea, and the existence of distinct groups among the isolates, with differences in antimicrobial resistance rates, suggests consideration of alternative agents to TMP/SMX to treat S. maltophilia infections and indicates the importance of accurate identification for appropriate selection of treatment options.

Clinical Usefulness of Plasma Quantitative Polymerase Chain Reaction Assay: Diagnosis of Cytomegalovirus Infection in Kidney Transplant Recipients

BACKGROUND Preemptive therapy is used to prevent cytomegalovirus (CMV) disease in transplant recipients. The CMV antigenemia assay, which has been commonly used as a predictive marker for preemptive therapy, requires intensive labor and immediate processing. We compared the cutoff value of plasma CMV polymerase chain reaction (PCR) with CMV antigenemia in kidney transplant recipients. METHODS We compared two diagnostic methods for CMV infection in kidney transplant recipients: quantitative PCR (qPCR) versus antigenemia. We evaluated the optimal cutoff value of plasma CMV qPCR by using receiver-operating characteristic curves for specific antigenemia values. All kidney transplant recipients from January 2004 to January 2005 were enrolled and followed with CMV antigenemia and plasma CMV qPCR. RESULTS The analyses were performed on 899 samples collected from 111 patients in the early posttransplant period, matching 84.1% of patients for the results of CMV antigenemia and plasma CMV qPCR. For patients with symptomatic CMV infection and disease, who showed ≥25 positive cells in the antigenemia assay, the cutoff value for qPCR was 17.8 copies/μL with a sensitivity of 97.1%, a specificity of 89.1%, and a positive predictive value of 26.6%. CONCLUSIONS Diagnostic assays for CMV such as CMV antigenemia and quantitative plasma PCR, showed similar diagnostic values. They are the methods of choice for the diagnosis and monitoring of active CMV infection after kidney transplantation. However, because of the relatively low positive predictive value of qPCR, this test may lead to unnecessary preemptive treatment in kidney transplant recipients.

Panipenem Versus Cefepime as Empirical Monotherapy in Adult Cancer Patients with Febrile Neutropenia : A Prospective Randomized Trial

OBJECTIVE To compare the efficacy and safety of panipenem/betamipron with cefepime as empirical monotherapy for adult cancer patients with febrile neutropenia, a randomized, open-label, comparative trial was performed. METHODS All enrolled patients were randomly assigned to receive either panipenem or cefepime. All febrile episodes were classified as microbiologically defined infection (MDI), clinically defined infection (CDI) or unexplained fever (UF). Clinical responses to antibiotic therapy were defined as success, initial response but regimen modified or failure. RESULTS A total of 116 patients were enrolled: 55 patients in the panipenem group and 61 patients in the cefepime group. Demographic and clinical characteristics were similar in the two groups (P > 0.05). In the final evaluation, the success rate for the panipenem group (89.1%) was similar to that of the cefepime group (91.8%) (non-inferiority, P = 0.002, 95% confidence interval: -13.48%, 10.35%). Of the 18 bacterial isolates, nine (50%) were gram-positive and nine (50%) were gram-negative. The prevalence of adverse events in the panipenem group (23.6%) were similar to those in the cefepime group (23.0%) (P = 0.93). All of the adverse events were well tolerated and transient. CONCLUSIONS Although larger studies are necessary, panipenem appeared to be as effective and safe as cefepime for empirical monotherapy in the treatment of adult cancer patients with febrile neutropenia.

Characteristics of community-onset NDM-1-producing Klebsiella pneumoniae isolates.

Multilocus sequence typing and in vitro antimicrobial susceptibility testing were performed for three community-onset New Delhi metallo-β-lactamase-1 (NDM-1)-producing Klebsiella pneumoniae isolates from Korea. The genetic structure surrounding the blaNDM-1 gene was determined in blaNDM-1-harbouring plasmids. Three NDM-1-producing K. pneumoniae isolates were found to belong to the same clone (sequence type 340). Each of these isolates showed the same genetic structure surrounding the blaNDM-1 gene. The genes blaNDM-1, bleMBL, trpF and dsbC were flanked by two intact insertion sequences, ISAba125 and IS26, which may promote horizontal gene transfer. The blaNDM-1-harbouring plasmids conferred antimicrobial resistance to carbapenems, cephalosporins, aminoglycosides and aztreonam in transconjugants. It can be speculated that either the entire blaNDM-1-harbouring plasmids or just the part of the plasmid containing the blaNDM-1 gene may have transferred between K. pneumoniae and Escherichia coli. Following the transfer, the isolate disseminated throughout Korea. This study suggests the need for monitoring the dissemination of NDM-1-producing isolates across countries or continents due to their potential transferability via ISAba125- and IS26-associated transposons.