Hee Jin Cheong

Long-term immunogenicity of influenza vaccine among the elderly: Risk factors for poor immune response and persistence ☆

The elderly have been considered as the priority group for influenza vaccination, but their influenza vaccine-induced antibody was believed to decline more rapidly. Long-term immunogenicity of the influenza vaccine among the elderly was evaluated as compared to young adults. Serum hemagglutinin inhibition (HI) titers were determined at pre- and post-vaccination periods (at 1, 6, and 12 months after vaccination). Of the 1018 subjects, 716 (70.3%) were followed up during a 12-month period. Seroprotection rates at 1 month post-vaccination ranged from 70.1% to 90.3% depending on the age group and influenza vaccine virus strain. At 6 months post-vaccination, seroprotection rates for all three strains had declined significantly in adults >or=65 years (P<0.01), but still met the EMEA criteria. Low pre-vaccination HI titer (<1:40) and advanced age were associated with early decline of HI titers, falling below seroprotective levels around 6 months after vaccination.

Influenza vaccine coverage rates and perceptions on vaccination in South Korea

Summary Objective This survey was performed to assess the level of influenza vaccine coverage, to understand the driving forces and barriers to vaccination and determine vaccination interventions for the following year in Korean population. Methods A national sample of 1720 community dwelling adults of age 18 and older were surveyed by individual visits during April 2005. Demographics, state of influenza vaccination, reasons for vaccination or non-vaccination and perceptions on vaccinations were asked by questionnaire. Results Influenza vaccination coverage in general population and high risk group was 34.3% and 61.3%, respectively. Predictors for vaccination were ≥65 of age, performance of regular exercise, vaccination in the previous season, experience of influenza-like illness, belief that vaccine can prevent common cold and opinion that vaccine must be taken annually. The most common reason for vaccination for both whole population and high risk groups was to prevent both influenza and common cold, while the most common reason for non-vaccination was the thought that he/she was healthy enough not to be in need for vaccination. Having more information on influenza and vaccination as well as doctors recommendation for vaccination appeared to be the most important modus operandi to encourage influenza vaccination among non-vaccinees. Conclusions Doctors recommendation was the most important factor in encouraging people to be vaccinated against influenza. Doctors should be geared up with precise information and actively encourage high risk population in order to increase vaccination coverage.

An outbreak of post-acupuncture cutaneous infection due to Mycobacterium abscessus

BackgroundDespite the increasing popularity of acupuncture, the importance of infection control is not adequately emphasized in Oriental medicine. In December 2001, an Oriental medical doctor in Seoul, South Korea, encountered several patients with persistent, culture-negative skin lesions on the trunk and extremities at the sites of prior acupuncture treatment. We identified and investigated an outbreak of Mycobacterium abscessus cutaneous infection among the patients who attended this Oriental medicine clinic.MethodsPatients were defined as clinic patients with persistent cutaneous infections at the acupuncture sites. Medical records for the previous 7 months were reviewed. Clinical specimens were obtained from the patients and an environmental investigation was performed. M. abscessus isolates, cultured from patients, were compared by pulsed-field gel electrophoresis (PFGE).ResultsForty patients who attended the Oriental medicine clinic and experienced persistent cutaneous wound infections were identified. Cultures from five of these patients proved positive, and all other diagnoses were based on clinical and histopathologic examinations. All environmental objects tested were negative for M. abscessus, however, most were contaminated by various nosocomial pathogens. Molecular analysis using PFGE found all wound isolates to be identical.ConclusionWe have identified a large outbreak of rapidly growing mycobacterial infection among patients who received acupuncture at a single Oriental medicine clinic. Physicians should suspect mycobacterial infections in patients with persistent cutaneous infections following acupuncture, and infection control education including hygienic practice, should be emphasized for Oriental medical doctors practicing acupuncture.

Red blood cell transfusions are associated with lower mortality in patients with severe sepsis and septic shock: a propensity-matched analysis*.

Objectives:To evaluate the effects of transfusions in patients with severe sepsis and septic shock on mortality. Design:Propensity-matched analysis of a prospective observational database (April 2005 to February 2009). Setting:Twenty-two medical and surgical intensive care units in 12 teaching hospitals in Korea. Patients:One thousand fifty-four patients with community-acquired severe sepsis and septic shock. InterventionsNone. Measurements and Main Results:Of the 1,054 patients, 407 (38.6%) received a blood transfusion. The mean pretransfusion hemoglobin level was 7.7 ± 1.2 g/dL. Transfused patients had higher 28-day and in-hospital mortality rates (32.7% vs. 17.3%; p < .001, 41.3% vs. 20.3%; p < .001, respectively) and a longer duration of hospital stay (21 [interquartile range, 10–35] vs. 13 [interquartile range, 8–24] days; p < .001), but were more severely ill at admission (lower systolic blood pressure, higher Acute Physiology and Chronic Health Evaluation II score, and Sequential Organ Failure Assessment score at admission). In 152 pairs matched according to the propensity score depending on patient transfusion status, transfused patients had a lower risk of 7-day (9.2% vs. 27.0%; p < .001), 28-day (24.3% vs. 38.8%; p = .007), and in-hospital mortality rates (31.6% vs. 42.8%; p = .044). After adjusting for blood transfusion as a time-dependent variable in multivariable analysis, blood transfusion was independently associated with lower risk of 7-day (hazard ratio 0.42, 95% confidence interval 0.19–0.50, p = .026), 28-day (hazard ratio 0.43, 95% confidence interval 0.29–0.62, p < .001), and in-hospital mortality (hazard ratio 0.51, 95% confidence interval 0.39–0.69, p < .001). Conclusions:In this observational study of patients with community-acquired severe sepsis and septic shock, red blood cell transfusions were associated with lower risk of mortality.

Efficacy of monotherapy and combined antibiotic therapy for carbapenem-resistant Acinetobacter baumannii pneumonia in an immunosuppressed mouse model

Acinetobacter baumannii is an important cause of nosocomial infection with increasing carbapenem resistance. The aim of this study was to compare the efficacy of colistin+rifampicin and imipenem+rifampicin combinations with that of several other antibiotic regimens against carbapenem-resistant A. baumannii pneumonia using an immunosuppressed mouse model. Three different A. baumannii strains with diverse resistance mechanisms (OXA-51-, IMP-1- and VIM-2-type beta-lactamases) were used. Among the monotherapy regimens, only rifampicin significantly reduced the bacterial load in lungs 24 h after infection with the OXA-51-producing strain. Addition of rifampicin to either imipenem or colistin yielded synergistic results after 48 h. Rifampicin was bactericidal against the IMP-1-producing strain, and only the imipenem+rifampicin combination yielded synergistic effects. In contrast, rifampicin alone was not effective against the VIM-2-producing strain, but the imipenem+rifampicin combination was bacteriostatic even at 24 h post-infection. Tigecycline and amikacin were not effective against any of the three strains. Rifampicin-based combinations were effective against A. baumannii bacteraemia and improved survival regardless of the strain type. Contrary to the similar minimum inhibitory concentration results, the antibacterial effects of rifampicin were quite different according to the strains; a tailored antibiotic strategy must be considered in treatment. Addition of rifampicin to either imipenem or colistin would be effective.

Characteristics of Non-typhoidal Salmonella Isolates from Human and Broiler-chickens in Southwestern Seoul, Korea

Non-typhoidal Salmonella (NTS) is an important commensal microorganism. The purpose of this study was to determine the epidemiological relation between NTS isolates from livestock and NTS isolates from human by analyzing antimicrobial susceptibilities and performing molecular typing. We determined the serotypes of 36 human clinical isolates and 64 livestock isolates, performed antimicrobial susceptibility testing against 8 antibiotics, and determined the molecular types of isolated NTS spp. by pulsed field gel electrophoresis (PFGE). In human isolates, S. enteritidis was the most common serotype (17 isolates; 47.2%) and S. typhimurium the second most (8 isolates; 22.2%). In livestock isolates, S. typhimurium was the most common serotype (15 isolates; 23.44%), and S. enteritidis was the second most (14 isolates; 21.88%). Ampicillin and tetracycline resistance were 50% (32/64 isolates) each among broiler-chicken NTS isolates. No human or livestock NTS isolates showed resistance to ciprofloxacin, TMP-SMX, or ceftriaxone. However, 19.4% (7/36) and 46.8% (30/64) of the human and livestock NTS isolates were resistant to nalidixic acid (MIC ≥16 mg/mL), respectively. The presence of the three identical PFGE molecular types from human and broiler-chicken NTS isolates suggests the possibility of transmission from livestock to humans.

Clinical outcome and predictive factors of recurrence among patients with Kikuchi's disease.

OBJECTIVES To evaluate the clinical outcome and predictive factors of recurrence among patients with Kikuchis disease. METHODS Between January 2001 and December 2006, all patients with Kikuchis disease were included in the study. Data were collected on co-morbidities, clinical manifestations, and ultrasound/laboratory findings, and the differences were compared between recurrent disease and non-recurrent disease groups. RESULTS The study included 102 patients with a mean age of 26.7 years. Among these patients, three developed systemic lupus erythematosus during the follow-up period, while two cases were later associated with tuberculosis. Eight patients (7.8%) experienced early relapse and 13 (12.7%) showed late recurrence. Patients with recurrent episodes were more likely to have fever and fatigue with extranodal involvement. Compared to the non-recurrent cases, recurrent cases remained symptomatic for a rather longer duration. The positive rate of the fluorescence anti-nuclear antibody (FANA) test was significantly higher in the recurrent disease group compared to the non-recurrent disease group. CONCLUSIONS Kikuchis disease took a self-limiting clinical course in most cases, but the recurrence rate found in the present study was higher than that of previous reports. Kikuchis disease might be a phenotype of diverse disease entities. The prognosis is different according to the underlying cause. The FANA test would be useful in predicting recurrence.

Prognostic Significance of Infection Acquisition Sites in Spontaneous Bacterial Peritonitis: Nosocomial versus Community Acquired

Spontaneous bacterial peritonitis (SBP) is an ascitic fluid infection as a complication of end stage liver disease. The outcome is related to the severity of hepatorenal function, gastrointestinal bleeding, and many others; however it is not well known whether the infection acquisition sites have an effect on the prognosis of SBP. In order to identify the prognostic significance of the acquisition sites, we studied 106 patients who were diagnosed as culture positive SBP between October 1998 and August 2003. Thirty-two episodes were nosocomial and 74 were community acquired. Gram-negative bacilli such as Escherichia coli were dominant in both of the nosocomial and community-acquired SBPs. Despite significantly higher resistance to cefotaxime in nosocomial isolates compared to community-acquired isolates (77.8% vs. 13.6%, p=0.001), no difference was found regarding short or long term prognosis. Infection acquisition sites were not related to short or long term prognosis either. Shock, gastrointestinal bleeding and renal dysfunction were related to short term prognosis. Only Child-Pugh class C was identified as an independent prognostic factor of long-term survival.

Colistin and rifampicin combination in the treatment of ventilator-associated pneumonia caused by carbapenem-resistant Acinetobacter baumannii

f VRE. A quantitative drug usage evaluation performed ndependently in our hospital from 2004 to 2006 revealed 104% increase in vancomycin usage. The qualitative rug usage evaluation results indicated that only 40% of he patients were prescribed vancomycin for one of the pproved indications according to the Hospital Infection ontrol Practices Advisory Committee (HICPAC) guidelines 7]. Having a malignant disease remained protective for RE in the multivariate model (OR 0.26, 95% CI 0.07– .97). The crude associated mortality rate was higher in atients with VRE infections (VRE 53.1% vs. VSE 32.3%; = 0.047). The total hospital stay (VRE 51.5 ± 27.8 days vs. SE 37.6 ± 29.6 days) was longer in VRE-infected patients han in those with VSE infections (P = 0.028).

Effectiveness of the pandemic influenza A/H1N1 2009 monovalent vaccine in Korea

The 2009 influenza pandemic was caused by a novel triple-reassortant influenza A/H1N1 virus that was further recombined with a Eurasian pig flu virus. Vaccination is a key countermeasure for disease; however, little data assessing vaccine effectiveness (VE) against the pandemic H1N1 virus are available. We conducted a matched case-control study to assess effectiveness of the 2009 influenza A/H1N1 monovalent vaccine against laboratory-confirmed, medically attended influenza patients. Subjects included in the study were ≥ 10 years of age and were treated at five university hospitals in the Republic of Korea (ROK) from December 2009 through March 2010. For subjects visiting outpatient clinics with influenza-like illness (ILI), real time reverse transcription polymerase chain reaction (rRT-PCR) was used to diagnose 2009 H1N1 influenza virus infection. Subjects with positive rRT-PCR were classified as cases, while those testing negative were controls. A valid vaccination corresponded to ≥ 14 days between receiving a dose of vaccine and symptom onset. Overall, 416 ILI subjects were analyzed, and 60 (14.4%) were vaccinated with the 2009 influenza A/H1N1 monovalent vaccine. The overall VE against pandemic 2009 A/H1N1 virus illness after adjustment for age group and presence of chronic medical conditions was 73.4% (95% confidence interval [CI]=49.1-86.1%). Both vaccine formulations (unadjuvanted and MF-59 adjuvanted) showed a statistically significant VE. In conclusion, the 2009 influenza A/H1N1 monovalent vaccine was substantially protective against pandemic influenza in the ROK during the 2009-2010 season.