Jun Hee Woo

Viral Infection in Patients with Severe Pneumonia Requiring Intensive Care Unit Admission

RATIONALE The role of viruses in pneumonia in adults and the impact of viral infection on mortality have not been elucidated. Previous studies have significant limitations in that they relied predominantly on upper respiratory specimens. OBJECTIVES To investigate the role of viral infection in adult patients with pneumonia requiring intensive care unit (ICU) admission. METHODS A retrospective analysis of a prospective cohort was conducted in a 28-bed medical ICU. Patients with severe community-acquired pneumonia (CAP) or healthcare-associated pneumonia (HCAP) were included in the study. MEASUREMENTS AND MAIN RESULTS A total of 198 patients (64 with CAP, 134 with HCAP) were included for analysis. Of these, 115 patients (58.1%) underwent bronchoscopic bronchoalveolar lavage (BAL), 104 of whom were tested for respiratory viruses by BAL fluid reverse-transcription polymerase chain reaction (RT-PCR). Nasopharyngeal specimen RT-PCR was performed in 159 patients (84.1%). Seventy-one patients (35.9%) had a bacterial infection, and 72 patients (36.4%) had a viral infection. Rhinovirus was the most common identified virus (23.6%), followed by parainfluenza virus (20.8%), human metapneumovirus (18.1%), influenza virus (16.7%), and respiratory syncytial virus (13.9%). Respiratory syncytial virus was significantly more common in the CAP group (CAP, 10.9%; HCAP, 2.2%; P = 0.01). The mortalities of patients with bacterial infections, viral infections, and bacterial-viral coinfections were not significantly different (25.5, 26.5, and 33.3%, respectively; P = 0.82). CONCLUSIONS Viruses are frequently found in the airway of patients with pneumonia requiring ICU admission and may cause severe forms of pneumonia. Patients with viral infection and bacterial infection had comparable mortality rates.

Emergence of Antibiotic Resistance during Therapy for Infections Caused by Enterobacteriaceae Producing AmpC β-Lactamase: Implications for Antibiotic Use

ABSTRACT Enterobacter spp., Serratia marcescens, Citrobacter freundii, and Morganella morganii are characterized by chromosomally encoded AmpC β-lactamases and possess the ability to develop resistance upon exposure to broad-spectrum cephalosporins. To determine the incidences of the emergence of resistance during antimicrobial therapy for infections caused by these organisms and the effect of the emergence of resistance on patient outcomes, all patients who were admitted to the Asan Medical Center (Seoul, Republic of Korea) from January 2005 to June 2006 and whose clinical specimens yielded Enterobacter spp., S. marcescens, C. freundii, or M. morganii were monitored prospectively. The main end point was the emergence of resistance during antimicrobial therapy. A total of 732 patients with infections were included for analysis. The overall incidence of the emergence of antimicrobial resistance during antimicrobial therapy was 1.9% (14/732). Resistance to broad-spectrum cephalosporins, cefepime, extended-spectrum penicillin, carbapenem, fluoroquinolones, and aminoglycosides emerged during treatment in 5.0% (11/218), 0% (0/20), 2.0% (2/100), 0% (0/226), 0% (0/153), and 1.1% (1/89) of patients, respectively. The emergence of resistance to broad-spectrum cephalosporins occurred more often in Enterobacter spp. (8.3%, 10/121) than in C. freundii (2.6%, 1/39), S. marcescens (0%, 0/37), or M. morganii (0%, 0/21). Biliary tract infection associated with malignant bile duct invasion was significantly associated with the emergence of resistance to broad-spectrum cephalosporins (P = 0.024 at a significance level of 0.042, by use of the Bonferroni correction). Only 1 of the 14 patients whose isolates developed resistance during antimicrobial therapy died. The emergence of resistance was more frequently associated with broad-spectrum cephalosporins than with the other antimicrobial agents tested, especially in Enterobacter spp. However, the emergence of resistance was associated with a low risk of mortality.

Rapid Diagnosis of Tuberculous Meningitis by T Cell—Based Assays on Peripheral Blood and Cerebrospinal Fluid Mononuclear Cells

BACKGROUND The role of the new Myocbacterium tuberculosis-specific enzyme-linked immunosorbent spot (ELISPOT) assay for diagnosis of tuberculous meningitis (TBM) has not yet been fully assessed. Here, we conducted a prospective, blinded, observational study to evaluate the diagnostic accuracy of this assay, compared with the conventional tests, for diagnosing TBM. METHODS All adult patients with suspected TBM were enrolled at a tertiary care hospital (Seoul, South Korea) during a 12-month period. ELISPOT assays were performed on peripheral mononuclear cells and mononuclear cells from cerebrospinal fluid (CSF). RESULTS Eighty-nine patients with suspected TBM were enrolled. Of these, 31 (35%) were classified as having TBM (10 confirmed, 6 highly probable, and 15 probable cases), and 55 (62%) were classified as not having active tuberculosis. The remaining 3 (3%) with possible TBM were excluded from the final analysis. The sensitivities and specificities, respectively, of the tested methods for diagnosing TBM were as follows: CSF adenosine deaminase level >5.8 U/L, 89% (95% confidence interval [CI], 69%-98%) and 73% (95% CI, 58%-84%); peripheral mononuclear cells ELISPOT, 71% (95% CI, 51%-86%) and 57% (95% CI, 42%-70%); and CSF mononuclear cells ELISPOT assay, 59% (95% CI, 36%-79%) and 89% (95% CI, 72%-98%). The combined sensitivity of an adenosine deaminase level >5.8 U/L or a positive peripheral mononuclear cells ELISPOT assay result was 94% (95% CI, 79%-99%), conferring a negative likelihood ratio of 0.14 (95% CI, 0.03-0.55) when both test results were negative. CONCLUSION ELISPOT assays using peripheral mononuclear cells and CSF mononuclear cells are useful adjuncts to the current tests for diagnosing TBM, particularly when used in combination with the assessment of adenosine deaminase level in CSF.

Detection of qnr in clinical isolates of Escherichia coli from Korea.

ABSTRACT qnr was detected in 2 of 260 Escherichia coli clinical isolates collected from a Korean hospital during the period 2001 to 2003. The two strains were not clonally related. qnr was located in In4 family class 1 integrons of original structure, downstream of orf513 and upstream from another resistance gene (dfrA3b) and a gene of unknown function (orf105). Transfer of the qnr determinant by conjugation could be detected from only one strain.

Aspergillus galactomannan antigen assay in bronchoalveolar lavage fluid for diagnosis of invasive pulmonary aspergillosis

OBJECTIVES A recently developed bronchoalveolar lavage (BAL) galactomannan (GM) assay shows promising results. We evaluated the diagnostic performance of this assay and analyzed risk factors for false-positive results. METHODS A prospective cohort study was performed in a tertiary hospital over a 9-month period. We reviewed all adult patients who underwent GM assays of BAL. Patients were categorized with proven, probable, or possible invasive pulmonary aspergillosis (IPA) according to revised EORTC/MSG definitions. Each patient with a false-positive BAL GM result was matched with three patients with true-negative BAL GM result, and the risk factors for false-positive BAL GM results were determined. RESULTS Of 359 enrolled patients, 22 (6%) were diagnosed with IPA (1 proven, 17 probable, and 4 possible). Of the 22 patients with IPA, 17 (77%) had already received antifungal agents before the BAL GM assay was conducted. At an index cutoff value of ≥0.5, the BAL GM assay had a sensitivity of 64% (95% CI 41%-83%) and a specificity of 89% (95% CI 85%-92%). However, at an index cutoff value of ≥0.2, the BAL GM assay had a sensitivity of 86% (95% CI 65%-97%) and a specificity of 74% (95% CI 69%-79%). Of the 52 patients with positive BAL GM assay (≥0.5), 25 (7%) were false-positives. Univariate and multivariate analysis revealed that treatment with piperacillin-tazobactam or ampicillin-sulbactam was associated with false-positive BAL GM results. CONCLUSIONS The BAL GM assay appears promising for the diagnosis of IPA. However, treatment with certain antibiotics may interfere with the results of the BAL GM assay.

Diagnostic Performance of the Cytomegalovirus (CMV) Antigenemia Assay in Patients with CMV Gastrointestinal Disease

Of 149 patients with suspected cytomegalovirus (CMV) gastrointestinal disease, 51 (36%) confirmed cases, 6 (4%) probable cases, and 64 (45%) instances of non-CMV gastrointestinal disease were analyzed using the CMV antigenemia assay; 22 patients (5%) with indeterminate gastrointestinal disease were excluded. The sensitivity and specificity of the CMV antigenemia assay (defined as detection of > or =1 positive cells per 200,000 leukocytes) for diagnosis of CMV gastrointestinal disease were 54% (95% confidence interval, 41%-68%) and 88% (95% confidence interval, 77%-94%), respectively.

Risk factors for the acquisition of carbapenem-resistant Escherichia coli among hospitalized patients

Carbapenem resistance among Gram-negative bacilli has become an increasingly serious problem worldwide, and the emergence and spread of carbapenem-resistant Escherichia coli (CREC) is also becoming a serious problem. To date, however, risk factors for CREC acquisition have not been determined, so we decided to evaluate this in hospitalized patients through matched case-control study. Nosocomially acquired CREC was isolated from 46 patients between January 1997 and December 2007. For each patient, 3 matched-control subjects were selected. Previous use of carbapenem (adjusted odds ratio [AOR], 6.50) and metronidazole (AOR, 4.25), the presence of biliary drainage catheter (AOR, 4.59), and prior hospital stay (AOR 1.02) were found as independent risk factors for CREC. Our results suggest that the nosocomial acquisition of CREC may be favored by the selection pressure of carbapenems and metronidazole and also related to prior hospital stay and the presence of biliary drainage catheter.

Nosocomial Clustering of NDM-1-Producing Klebsiella pneumoniae Sequence Type 340 Strains in Four Patients at a South Korean Tertiary Care Hospital

ABSTRACT In November 2010, NDM-1-producing Klebsiella pneumoniae (NDMKP) was identified for the first time in South Korea from four patients with no history of traveling abroad who stayed for 21 to 205 days in a tertiary care hospital. All were sequence type (ST) 340 and had nearly identical XbaI pulsed-field gel electrophoresis (PFGE) patterns. The bla NDM-1-carrying plasmids were in the IncN group, with sizes ranging from 50 to 200 kb. These findings suggest that NDMKP had already been introduced into South Korea before this clustering was found.

Paradoxical responses in non-HIV-infected patients with peripheral lymph node tuberculosis

OBJECTIVES We evaluated the clinical characteristics and risk factors for the paradoxical response (PR) in non-HIV-infected patients with peripheral lymph node tuberculosis (TB). METHODS Medical records of non-HIV-infected patients aged > or =16 years with peripheral lymph node TB treated in a tertiary hospital between January 1997 and August 2007 were analysed. PR was defined as clinical or radiological worsening of pre-existing TB lesions, or development of new lesions in a patient who had received anti-TB therapy for at least 2 weeks. RESULTS Three hundred patients with lymph node TB were included. Of these, 235 patients (78%) had confirmed TB; the remaining 65 (22%) had probable TB and were excluded from the final analysis. Among the 235 study patients, their mean age (+/-standard deviation) was 37.6 (+/-13.9) years and 175 (75%) were female. PR occurred in 54 (23%; 95% confidence interval 18-28%) patients, at a median onset time of 8 weeks (interquartile range, 4-14 weeks) after starting anti-TB medication. In multivariate analysis, younger age (OR 0.96), male gender (OR 2.60), and the presence of local tenderness at the time of diagnosis (OR 2.90) were independently associated with PR. CONCLUSION PR was relatively common, occurring in one-fifth of non-HIV-infected patients with peripheral lymph node TB, and was associated with younger age, male gender, and the presence of local tenderness.

Outcomes of Moderate-to-Severe Pneumocystis Pneumonia Treated with Adjunctive Steroid in Non-HIV-Infected Patients

ABSTRACT While it is well-known that adjunctive corticosteroid use improves the outcome of moderate-to-severe Pneumocystis jirovecii pneumonia (PcP) in patients with human immunodeficiency virus (HIV), there are limited data on its efficacy in non-HIV-infected patients with PcP. Patients undergoing fiber-optic bronchoscopy with bronchoalveolar lavage for suspected PcP from January 2007 through December 2010 were reviewed retrospectively. We compared demographics, clinical characteristics, and outcomes in 88 non-HIV-infected patients with moderate-to-severe PcP with (n = 59) and without (n = 29) adjunctive corticosteroid use. Outcomes of PcP were assessed by respiratory failure and 30-day and 90-day all-cause mortality. Survival curves were analyzed by the Kaplan-Meier method and estimated by the log rank test. All-cause mortality of moderate-to-severe PcP at 90 days was lower in the solid-organ transplant recipients than in all other patients (6/26 [23%] versus 34/62 [55%], respectively; P = 0.006), and mortality at 30 days was lower in patients with hematologic malignancies than in all other patients (4/26 [15%] versus 24/62 [39%], respectively; P = 0.03). The outcomes of PcP were not significantly different in moderate-to-severe PcP patients with and without adjunctive corticosteroid use, regardless of recent corticosteroid use. Survival analysis of PcP patients with and without corticosteroid use by the Kaplan-Meier method also did not reveal any difference (log rank test; P = 0.81). There again was no difference within the subgroup of PcP patients with solid-organ transplants. Adjunctive corticosteroid use may not improve the outcome of moderate-to-severe PcP in non-HIV-infected patients.