Efficacy of Influenza Vaccination among Chronic Ill Patients: Retrospective Case Control Study / 감염과화학요법

BACKGROUND: Influenza is one of the preventable respiratory disease by annual vaccination. Elderly people and patients with chronic medical disease are the primary target for influenza vaccination according to ACIP (Advisory Committee on Immunization). This study was done to determine whether influenza vaccination affects hospitalization due to influenza like illness or it's related complications among chronic ill patients. MATERIALS AND METHODS: Retrospective, case-control study was conducted for 5 months (Nov. 1999-Mar. 2000). Physicians from two-university hospitals in Korea were instructed to collect clinical data, sera from subjects presenting with a flu-like illness or flu-related exacerbation in patients with chronic underlying diseases. We compared the vaccination history of case patients with control. Logistic regression analysis was used to calculate the odd ratio and efficacy of influenza vaccination. RESULTS: Hospitalization due to ILI (influenza like illness) or it's related complications were observed more frequently in patients with chronic lung disease (25.3%) and chronic cardiac disease (31.3%) compared to others. Influenza vaccination resulted in fewer hospitalization with ILI or ILI-related acute exacerbation of underlying disease in chronic ill patients (adjusted odd ratio, 0.328 [CI, 0.14 to 0.73]) during influenza seasons. CONCLUSION: For patients with chronic disease, influenza vaccination is associated with substantial health benefit including fewer hospitalization. Health care providers should take advantage of all opportunities to immunize these high-risk patients.

Factors Influencing Decision Regarding Influenza Vaccination: A Survey of Healthcare Workers in One Hospital / 감염과화학요법

BACKGROUND: In spite of yearly recalls, influenza immunization rate among healthcare workers (HCWs) remained low in Korea University Guro Hospital. This study was conducted to identify the causes of non-compliance against influenza immunization and to analyze the barrier factors for the immunization. MATERIALS & METHODS: Questionnaires were distributed in March of 2000 at Korea University Guro Hospital. We evaluated factors associated with acceptance of influenza vaccination and opinions regarding influenza prevention (knowledge about influenza vaccination efficacy, que to action in vaccinee, perceptible benefit, barrier to vaccination). RESULTS: 309 completed questionnaires from HCWs were returned. Mean age and mean duration of work in hospital were higher and longer among vaccinee than non-vaccinee. Even though the necessity of influenza vaccination among HCWs were accepted well in vaccinee compared to non- vaccinee, the accurate reasons for vaccination were not quite understood among HCWs regardless of compliance. Vaccine campaign (30.8%) and advise from doctors (24.7%) were important for the promotion of vaccination among vaccinee. However, major reason for non-compliance among nursing staff and was mis-confidence that their bodies' self defense mechanisms would ward off infection (33.5%) and 'too busy to get injection' for doctors (65%). CONCLUSION: We conclude that regular education about perceptible benefits and wrong concerns about influenza vaccination among HCW's and easy accessibility to vaccination were important determinants to improve the influenza vaccination. On-site availability of a vaccination-nurse also proved to be important.

Efficacy of Influenza Vaccination among Chronic Ill Patients: Retrospective Case Control Study / 감염과화학요법

BACKGROUND: Influenza is one of the preventable respiratory disease by annual vaccination. Elderly people and patients with chronic medical disease are the primary target for influenza vaccination according to ACIP (Advisory Committee on Immunization). This study was done to determine whether influenza vaccination affects hospitalization due to influenza like illness or it's related complications among chronic ill patients. MATERIALS AND METHODS: Retrospective, case-control study was conducted for 5 months (Nov. 1999-Mar. 2000). Physicians from two-university hospitals in Korea were instructed to collect clinical data, sera from subjects presenting with a flu-like illness or flu-related exacerbation in patients with chronic underlying diseases. We compared the vaccination history of case patients with control. Logistic regression analysis was used to calculate the odd ratio and efficacy of influenza vaccination. RESULTS: Hospitalization due to ILI (influenza like illness) or it's related complications were observed more frequently in patients with chronic lung disease (25.3%) and chronic cardiac disease (31.3%) compared to others. Influenza vaccination resulted in fewer hospitalization with ILI or ILI-related acute exacerbation of underlying disease in chronic ill patients (adjusted odd ratio, 0.328 [CI, 0.14 to 0.73]) during influenza seasons. CONCLUSION: For patients with chronic disease, influenza vaccination is associated with substantial health benefit including fewer hospitalization. Health care providers should take advantage of all opportunities to immunize these high-risk patients.

Factors Influencing Decision Regarding Influenza Vaccination: A Survey of Healthcare Workers in One Hospital / 감염과화학요법

BACKGROUND: In spite of yearly recalls, influenza immunization rate among healthcare workers (HCWs) remained low in Korea University Guro Hospital. This study was conducted to identify the causes of non-compliance against influenza immunization and to analyze the barrier factors for the immunization. MATERIALS & METHODS: Questionnaires were distributed in March of 2000 at Korea University Guro Hospital. We evaluated factors associated with acceptance of influenza vaccination and opinions regarding influenza prevention (knowledge about influenza vaccination efficacy, que to action in vaccinee, perceptible benefit, barrier to vaccination). RESULTS: 309 completed questionnaires from HCWs were returned. Mean age and mean duration of work in hospital were higher and longer among vaccinee than non-vaccinee. Even though the necessity of influenza vaccination among HCWs were accepted well in vaccinee compared to non- vaccinee, the accurate reasons for vaccination were not quite understood among HCWs regardless of compliance. Vaccine campaign (30.8%) and advise from doctors (24.7%) were important for the promotion of vaccination among vaccinee. However, major reason for non-compliance among nursing staff and was mis-confidence that their bodies' self defense mechanisms would ward off infection (33.5%) and 'too busy to get injection' for doctors (65%). CONCLUSION: We conclude that regular education about perceptible benefits and wrong concerns about influenza vaccination among HCW's and easy accessibility to vaccination were important determinants to improve the influenza vaccination. On-site availability of a vaccination-nurse also proved to be important.

Clinical Characteristics and Risk Factors of Death among Patients with Vancomycin-Resistant Enterococci (VRE) during 8 Years (1994-2001) in a University Hospital / 감염과화학요법

BACKGROUND: Vancomycin-resistant enterococci (VRE) infection is an emerging nosocomial problem. VRE usually multidrug-resistant, poses therapeutic dilemmas. The gene that encodes the resistance against vancomycin may spread the resistance to Staphylococcus aureus. However, there are no well-organized studies on the clinical manifestations and the factors that contribute to mortality in Korea. Herein, this study was focused on the clinical manifestations and mortality risks of patients with VRE infection during 8 years (1994-2001) in a university hospital. Understanding of the epidemiology and clinical manifestations of VRE would help develop control strategy of VRE outbreak in a hospital. METHOD: Sixty seven cases that had the VRE infection in Korea University Guro Hospital from January 1, 1994to December 12, 2001, were reviewed. We analyzed the risk factors of VRE infection and death by using univariable and multivariable statistic analyses. RESULTS: VRE infections have recently been increasing. Most of VRE infections were caused by Enterococcus faecium (85.1%) and Enterococcus faecalis (10.4%). Among 67 cases, 40 cases (59.7%) expressed VanA phenotype, 23 cases (34.3%) expressed VanB phenotype, and 3 cases expressed VanC phenotype (6%). The risk factors for death were renal dysfunction, central venous catheter insertion, and tracheostomy by using univariable analysis. The risk factor for death was renal dysfunction by using multivariable analysis. CONCLUSION: VRE has been increasing during the late 1990s in Korea. The VRE infection occurs especially in the patients who have renal dysfunction, long-term hospitalization, and ICU care. The implementation of careful isolation, infection control measures, prudent use of antibiotics, especially vancomycin, and periodic screening of patients populations are required to control VRE infection.

Evaluation of the Appropriateness of Approved Antibiotic Usage Guidlines in Korea: Comparison of Domestic Package Inserts with Physicians' Desk Reference / 감염과화학요법

BACKGROUND: The appropriate usage of antibiotics needs informations such as its effectiveness for a given infection, administration route, the amount of effective dose, and the dose intervals. In this study, in order to find any significant discrepancy regarding to the details of explanation of the necessary information for appropriate antibiotic usages, we compares informations about 51 antibiotics, one from package inserts in Korea and the other from physician's desk reference (PDR) certified by FDA in the United States of America. MATERIALS AND METHODS: Package inserts about antibiotics, only oral or parenteral agent, were perused to collect three categories of data: the recommended dosage, dose interval, and adjustment of dose to indications or the severity of infection. These data available in Korea were compared with 61 antibiotics (32 oral and 29 parenteral agents) cited in PDR. RESULTS: Package inserts for 51 antibiotics were gathered, because the remaining 10 antibiotics in PDR are not domestically commercialized. Among data on antibiotics comparable with those in PDR, 59% (30 cases:15 oral and 15 parenteral agents) suggested the dose similar to that of PDR, 37% (19 cases:8 oral and 11 parenteral agents) recommend less dose, and 4% in only 2 oral agents showed more dose. About half of the drugs recommending lower dosage were imported from Japanese pharmaceutical company, and the recommended doses of these antimicrobial agents were similar to those in Japan. About 59% (30 cases: 15 oral and 15 parenteral agents) directed dose interval or duration similar to those of PDR and 17% (9 parenteral agents) suggested less administration or longer duration. Surprisingly, in contrast to only 6% (3 cases) of PDR, 24% (12 cases:10 oral and 2 parenteral agents) recommended more administration or shorter duration. About 39% (24 cases:13 oral and 7 parenteral agents) revealed no information for dose adjustment commens to indications or the severity of infection. CONCLUSION: This study revealed that many guidelines in Korea recommend lower doses and/or unreasonable dose intervals. In future studies, improved antibiotic usage guidelines should be established based on pharmacokinetic and pharmacodynamic researches, on the aspect of optimal dosage, dose interval, and dose adjustment commensurate to the indications and the severity of the infection.

In vitro Antimicrobial Activity of Linezolid (Zyvox(R)) against Multidrug Resistant Gram-Positive Organism / 감염과화학요법

BACKGROUND: The emergence of multi-drug resistant Gram-positive cocci, such as MRSA, VRE, and VRSA, necessitated to develop new antibiotics, which could replace the glycopeptide. As a result, a new antibiotics named linezolid was developed. Linezolid is different line of oxazolidinones with a good oral bioavailability, compared to other antibiotics. Since appropriate oral antibiotics are not presently available for MRSA, which is a major cause of nosocomial and community acquired infections, the introduction of linezolid will have favorable effect on treatment of infections such as pneumonia or skin infections. In this study, we investigated the antibiotic effect of linezolid on MRSA and VRE isolated from patients who were treated in Korea University Guro Hospital. MATERIAL AND METHODS: By using broth microdilution and agar dilution method we measured minimum inhibitory concentration (MIC) with sixty S. aureus, forty three Enterococcus spp., and twenty five S. pneumoniae isolates from patients who were diagnosed as skin, soft tissue, respiratory, and urinary infections in Korea University Guro Hospital from January, 1998 to December, 2002. RESULTS: All of S. aureus used in this study were MRSA, and MIC90 of linezolid was below 2 microgram/ml (MIC ranged between 1-2 microgram/ml). All of Enterococcus spp. were VRE, and had MIC90 of 2 microgram/ml (MIC ranged between 1 to 4 microgram/ml). One of the VRE showed intermediate susceptibility with MIC of 4 microgram/ml. However, none was resistant with MIC breakpoint above 8 microgram/ml. All of S. pneumoniae were resistant to penicillin, but they were susceptible to linezolid with MIC90 of 1 microgram/ml(MIC range 0.5-1 microgram/ml). CONCLUSION: In conclusions, linezolid has an excellent in vitro antibiotic effect on multi-drug resistant Gram-positive cocci, such as MRSA, PRSP, and VRE.

Antimicrobial Susceptibility of Causative Microorganisms in Adults with Acute Pyelonephritis at One University-Affiliated Hospital in Southwestern Seoul / 감염과화학요법

BACKGROUND: The purpose of this study is to recommend the initial therapeutic regimen for adult patients with acute pyelonephritis (APN) according to the changes of antimicrobial susceptibility patterns of causative microorganisms isolated from patients with APN. METHODS: We reviewed medical charts of 229 APN patients, who had been treated at Korea University Guro Hospital from 1st of January, 1999 to 31st of December, 2001. We investigated the demographic data, clinical findings, durations of hospital treatment, antimicrobial susceptibility patterns of the causative microorganisms and initial antibiotic regimens in patients with APN. RESULTS: In this study, 229 adult patients with APN were classified into simple APN patients (118 patients, 51.5%) and complicated APN patients (111 patients, 48.4%). Mean age of patients with simple APN was 38.2+/-14.1 years old and that of patients with complicated APN was 56.1+/-14.9 years old. Mean age of patients with complicated APN was significantly higher than that of simple APN patients (P<0.0001). Escherichia coli was the most common microorganism both in simple APN (96.7%) group and in complicated APN (90.6%) group. Antimicrobial susceptibility of E. coli was at the low level of ampicillin (31%/20%) and trimethoprim-sulfamethoxazole (42.6%/34.2%) in each group. In contrast, ciprofloxacin (11.5%/22.7%), gentamicin (16.4%/22%) and cefotaxime (0%/8.2%) resistance remained at relatively lower level. In comparison of simple APN with complicated APN, ciprofloxacin and gentamicin resistances were higher in complicted APN group. Average duration of hospitalization (5.9+/-2.3 days/8.2+/-4.6 days) and duration of antibiotic use (12.1+/-3.9 days/15.3+/-10.0 days) were significantly longer in complicated APN. CONCLUSIONS: The results of this study suggests that 3rd cephalosporin, aminoglycoside or quinolone antibiotic would considered as one of the initial therapeutic regimen for patients with simple APN in southwestern Seoul.

Clinical Characteristics and Risk Factors of Death among Patients with Vancomycin-Resistant Enterococci (VRE) during 8 Years (1994-2001) in a University Hospital / 감염과화학요법

BACKGROUND: Vancomycin-resistant enterococci (VRE) infection is an emerging nosocomial problem. VRE usually multidrug-resistant, poses therapeutic dilemmas. The gene that encodes the resistance against vancomycin may spread the resistance to Staphylococcus aureus. However, there are no well-organized studies on the clinical manifestations and the factors that contribute to mortality in Korea. Herein, this study was focused on the clinical manifestations and mortality risks of patients with VRE infection during 8 years (1994-2001) in a university hospital. Understanding of the epidemiology and clinical manifestations of VRE would help develop control strategy of VRE outbreak in a hospital. METHOD: Sixty seven cases that had the VRE infection in Korea University Guro Hospital from January 1, 1994to December 12, 2001, were reviewed. We analyzed the risk factors of VRE infection and death by using univariable and multivariable statistic analyses. RESULTS: VRE infections have recently been increasing. Most of VRE infections were caused by Enterococcus faecium (85.1%) and Enterococcus faecalis (10.4%). Among 67 cases, 40 cases (59.7%) expressed VanA phenotype, 23 cases (34.3%) expressed VanB phenotype, and 3 cases expressed VanC phenotype (6%). The risk factors for death were renal dysfunction, central venous catheter insertion, and tracheostomy by using univariable analysis. The risk factor for death was renal dysfunction by using multivariable analysis. CONCLUSION: VRE has been increasing during the late 1990s in Korea. The VRE infection occurs especially in the patients who have renal dysfunction, long-term hospitalization, and ICU care. The implementation of careful isolation, infection control measures, prudent use of antibiotics, especially vancomycin, and periodic screening of patients populations are required to control VRE infection.

Evaluation of the Appropriateness of Approved Antibiotic Usage Guidlines in Korea: Comparison of Domestic Package Inserts with Physicians' Desk Reference / 감염과화학요법

BACKGROUND: The appropriate usage of antibiotics needs informations such as its effectiveness for a given infection, administration route, the amount of effective dose, and the dose intervals. In this study, in order to find any significant discrepancy regarding to the details of explanation of the necessary information for appropriate antibiotic usages, we compares informations about 51 antibiotics, one from package inserts in Korea and the other from physician's desk reference (PDR) certified by FDA in the United States of America. MATERIALS AND METHODS: Package inserts about antibiotics, only oral or parenteral agent, were perused to collect three categories of data: the recommended dosage, dose interval, and adjustment of dose to indications or the severity of infection. These data available in Korea were compared with 61 antibiotics (32 oral and 29 parenteral agents) cited in PDR. RESULTS: Package inserts for 51 antibiotics were gathered, because the remaining 10 antibiotics in PDR are not domestically commercialized. Among data on antibiotics comparable with those in PDR, 59% (30 cases:15 oral and 15 parenteral agents) suggested the dose similar to that of PDR, 37% (19 cases:8 oral and 11 parenteral agents) recommend less dose, and 4% in only 2 oral agents showed more dose. About half of the drugs recommending lower dosage were imported from Japanese pharmaceutical company, and the recommended doses of these antimicrobial agents were similar to those in Japan. About 59% (30 cases: 15 oral and 15 parenteral agents) directed dose interval or duration similar to those of PDR and 17% (9 parenteral agents) suggested less administration or longer duration. Surprisingly, in contrast to only 6% (3 cases) of PDR, 24% (12 cases:10 oral and 2 parenteral agents) recommended more administration or shorter duration. About 39% (24 cases:13 oral and 7 parenteral agents) revealed no information for dose adjustment commens to indications or the severity of infection. CONCLUSION: This study revealed that many guidelines in Korea recommend lower doses and/or unreasonable dose intervals. In future studies, improved antibiotic usage guidelines should be established based on pharmacokinetic and pharmacodynamic researches, on the aspect of optimal dosage, dose interval, and dose adjustment commensurate to the indications and the severity of the infection.

In vitro Antimicrobial Activity of Linezolid (Zyvox(R)) against Multidrug Resistant Gram-Positive Organism / 감염과화학요법

BACKGROUND: The emergence of multi-drug resistant Gram-positive cocci, such as MRSA, VRE, and VRSA, necessitated to develop new antibiotics, which could replace the glycopeptide. As a result, a new antibiotics named linezolid was developed. Linezolid is different line of oxazolidinones with a good oral bioavailability, compared to other antibiotics. Since appropriate oral antibiotics are not presently available for MRSA, which is a major cause of nosocomial and community acquired infections, the introduction of linezolid will have favorable effect on treatment of infections such as pneumonia or skin infections. In this study, we investigated the antibiotic effect of linezolid on MRSA and VRE isolated from patients who were treated in Korea University Guro Hospital. MATERIAL AND METHODS: By using broth microdilution and agar dilution method we measured minimum inhibitory concentration (MIC) with sixty S. aureus, forty three Enterococcus spp., and twenty five S. pneumoniae isolates from patients who were diagnosed as skin, soft tissue, respiratory, and urinary infections in Korea University Guro Hospital from January, 1998 to December, 2002. RESULTS: All of S. aureus used in this study were MRSA, and MIC90 of linezolid was below 2 microgram/ml (MIC ranged between 1-2 microgram/ml). All of Enterococcus spp. were VRE, and had MIC90 of 2 microgram/ml (MIC ranged between 1 to 4 microgram/ml). One of the VRE showed intermediate susceptibility with MIC of 4 microgram/ml. However, none was resistant with MIC breakpoint above 8 microgram/ml. All of S. pneumoniae were resistant to penicillin, but they were susceptible to linezolid with MIC90 of 1 microgram/ml(MIC range 0.5-1 microgram/ml). CONCLUSION: In conclusions, linezolid has an excellent in vitro antibiotic effect on multi-drug resistant Gram-positive cocci, such as MRSA, PRSP, and VRE.

Antimicrobial Susceptibility of Causative Microorganisms in Adults with Acute Pyelonephritis at One University-Affiliated Hospital in Southwestern Seoul / 감염과화학요법

BACKGROUND: The purpose of this study is to recommend the initial therapeutic regimen for adult patients with acute pyelonephritis (APN) according to the changes of antimicrobial susceptibility patterns of causative microorganisms isolated from patients with APN. METHODS: We reviewed medical charts of 229 APN patients, who had been treated at Korea University Guro Hospital from 1st of January, 1999 to 31st of December, 2001. We investigated the demographic data, clinical findings, durations of hospital treatment, antimicrobial susceptibility patterns of the causative microorganisms and initial antibiotic regimens in patients with APN. RESULTS: In this study, 229 adult patients with APN were classified into simple APN patients (118 patients, 51.5%) and complicated APN patients (111 patients, 48.4%). Mean age of patients with simple APN was 38.2+/-14.1 years old and that of patients with complicated APN was 56.1+/-14.9 years old. Mean age of patients with complicated APN was significantly higher than that of simple APN patients (P<0.0001). Escherichia coli was the most common microorganism both in simple APN (96.7%) group and in complicated APN (90.6%) group. Antimicrobial susceptibility of E. coli was at the low level of ampicillin (31%/20%) and trimethoprim-sulfamethoxazole (42.6%/34.2%) in each group. In contrast, ciprofloxacin (11.5%/22.7%), gentamicin (16.4%/22%) and cefotaxime (0%/8.2%) resistance remained at relatively lower level. In comparison of simple APN with complicated APN, ciprofloxacin and gentamicin resistances were higher in complicted APN group. Average duration of hospitalization (5.9+/-2.3 days/8.2+/-4.6 days) and duration of antibiotic use (12.1+/-3.9 days/15.3+/-10.0 days) were significantly longer in complicated APN. CONCLUSIONS: The results of this study suggests that 3rd cephalosporin, aminoglycoside or quinolone antibiotic would considered as one of the initial therapeutic regimen for patients with simple APN in southwestern Seoul.

Clinical Aspects and Prognostic Factors of Neutropenic Fever in Leukemic Patients: 1996~2001 / 감염

BACKGROUND: Cancer therapy-related infections due to neutropenia is a well known problem in cancer treatment. Leukemia increases the risk furthermore because of its nature of bone marrow involvement. Therefore knowledge of the aspects of infections in neutropenic leukemic patients are important in preventing morbidity and mortality. METHODS: This study was conducted by reviewing clinical records of 69 cases of 49 leukemic patients who had neutropenic fever during 1996~2001. Each case was reviewed and analyzed in terms of clinical status & treatment, laboratory results, origins of fever and pathogens (if origin was infectious), final outcome and prognostic factors. RESULTS: Of 69 cases of 49 leukemic patients with neutropenic fever, mortalilty was 29%. Microbiologically defined infection (MDI) was 45% and clinically defined infection (CDI) was 30.4%, which meant a increase in MDIs compared with the previous study. Major focuses of fever were lung, blood and catheter-related, which were similar to those of 1988~1995. The major pathogens were gram negative bacilli (43.2%), followed by gram positive cocci (29.7%), but the proportion of gram positive pathogens had increased. Age, usage of selective gut decontamination and colony-stimulating factors (CSFs), and the presence of bone marrow recovery were related to prognosis by univariate analysis. Multivariate logistic regression analysis revealed that the bone marrow recovery was the only significantly related to patient's outcome, which was the same as the previous study (P<0.001). CONCLUSION: Proportions of pathogens in febrile neutropenic patients were similar with the previous study, but gram positive infections are increasing recently. Bone marrow recovery was the only significant prognostic factor in these patients. And, the benefits of selective gut decontamination or CSF usage is still questionable.

Clinical and Microbiological Feature of Quinolone-Resistant Klebsiella pneumoniae Pneumonia in a University Hospital / 감염

BACKGROUND: Klebsiella pneumoniae is an opportunistic pathogen which causes a spectrum of extra- intestinal infections. Since early 1980s, many outbreaks of extended-spectrum beta-lactamase (ESBL) producing K. pneumoniae have been reported. Using quinolone as an alternative therapeutic antibiotics also induced increased resistance to quinolones. Therefore, we evaluatedted the clinical and microbiological features of pneumonia caused by quinolone-resistant K. pneumoniae (QRKP). METHODS: From March of 1998 to April of 2000, 345 cases of K. pneumoniae pneumonia had been admitted to Korea University Guro Hospital. We retrospectively reviewed medical records of 75 cases. Thirty patients with pneumonia due to QRKP (case patients) were compared to 45 patients with pneumonia due to quinolone-susceptible K. pneumoniae (QSKP: control patients). We also performed antimicrobial susceptibility test (disc diffusion method and agar dilution method) and RAPD (random amplified polymorphic DNA) analysis to differentiate the isolates in resistant strains. RESULTS: Of 345 episodes of pneumonia, 30 (8.7 %) were caused by QRKP. Multivariate analysis re-vealed that prior antibiotics use was an independent risk factor for QRKP pneumonia. Among prior antibiotics, quinolone and the third generation cephalosporin were independently related to quinolone resistance. Although mortality rate was not high, QRKP pneumonia was associated with a significantly longer treatment duration and poor treatment response (P=0.009 and 0.007 respectively). According to the antimicrobial susceptibility test, quinolone resistance was significantly associated with the multi-drug resistance. RAPD analysis showed that 28 quinolone resistant strains belonged to only 4 genotypes, suggesting that patient- to-patient transmission of a few strains within the hospital occurred. CONCLUSION: QRKP pneumonia had a significant impact on clinical outcome and quinolone resistance was associated with multiple resistance to other antibiotics. It should be emphasized that judicious use of antibiotics as well as barrier precautions is required to reduce future outbreak and spread of QRKP.

Colonization Rate, Risk Factor for Acquisition and Genetic Diversity of Vancomycin-Resistant Enterococci (VRE) Isolated from Rectal Culture of Patients in Intensvie Care Units from Ten Large Hospitals in Korea / 감염

BACKGROUND: VRE have become an emerging nosocomial pathogen in Korea, but there has not been nationwide study on the colonization of VRE among high risk groups of hospitalized patients. The purpose of this study was to determine the prevalence of rectal colonization of VRE among patients hospitalized in the intensive care unit (ICU), to study the risk factors for nosocomial acquisition of VRE among those patients, to define the genetic diversity of VRE strains in major hospitals in Korea. METHODS: Between January the 20th and 30th of 2000, a point surveillance study was conducted in the ICU of the ten large hospitals, which were located nationwide. Surveillance rectal swab cultures for detecting VRE were obtained among 214 patients admitted to the ICU during the study period. To isolate VRE, rectal swab cultures were performed on Enterococcosel(R) agar that containing 6 microgram/mL of vancomycin. Minimal inhibitory concentrations (MICs) of vancomycin and teicoplanin were determined by agar dilution method. For the genotyping of VRE isolates, the detection of vanA, vanB, vanC1 and vanC2 gene by polymerase chain reaction was done. Pulsed-field gel electrophoreis (PFGE) was used for elucidating the genetic relatedness of VRE isolates. To identify the risk factors for rectal VRE colonization, patients harboring VRE were compared to patients who were not colonized with this organism. RESULTS: The rectal colonization rate of VRE was variable from 9.7% to 51.9% according to hospital. 64 VRE strains which were isolated from 63 patients included 37 E. feacium. 26 E. gallinarum and 1 E. casseliflavus isolates. Therefore the colonization rate of clinically significant vanA type VRE was 17.3% (37/ 214). 37 E. feacium. 26 E. gallinarum and 1 E. casseliflavus isolates were presented as vanA, vanC1 and vanC2 genotypes, respectively. Risk factors for rectal VRE colonization included the presence of chronic illness, previous use of broad spectrum antibioitcs es-pecillay vancomycin, and prolonged stay in ICU. Various PFGE patterns are noted among vanA type VRE isolates, so individual acquisition of VRE during stay in the majority of ICUs were suggested. But there is some evidence of focal VRE spread within the ICU and between hospitals. CONCLUSION: This study demonstrated the high rectal colonization rate (17.3%) of clinically significant vanA type VRE among patients admitted to the ICUs of ten large hospitals located nation-widely. This study suggested that practicing HICPAC guidelines, restricted vancomycin usage and periodic surveillance cultures in patients with high risk factors are important in preventing the emergence and spread of VRE infection among ICU patients.

Clinical Features of VRE Infection, Microbiologic Characteristics and Genetic Relatedness of VRE Isolates from Six University Hospitals / 감염

BACKGROUND: In recent years, vancomycin-resistant enterococci (VRE) have become one of major nosocomial pathogens in Korea. VRE infection presents as an increasingly difficult clinical problem in the treatment and management. The purpose of this study was to determine the clinical features, microbiologic characteristics, and genetic relatedenss of clinical VRE isolates which were collected from six university hospitals, distributed nationwide in Korea. In addition, we aimed to elucidate the possibility of VRE dissemination between hospitals. METHODS: During one year (January, 1999 to January, 2000), 107 clinically suspected VRE isolates were collected from six university hospitals and were subjected to vancomycin resistance genotyping by vanA, vanB, vanC1 and vanC2 PCR. Those 70 isolates with vanA genotype were examined antimicrobial susceptibility by agar dilution method. Pulsed-field gel electrophoreis (PFGE) were used for discriminating the genetic relatedness of VRE isolates. Clinical characteristics of the 61 patients with vanA VRE infection were analyzed for the identification of risk factors for VRE infection. RESULTS: Out of 107 clinical VRE isolates from six hospitals, 70 isolates (65.4%) were vanA genotype VRE (67 E. faecium, 3 E. faecalis). Their MIC90 of vancomycin, teicoplanin and ampicillin were >512 microgram mL, 512 microgrammL and >512 microgrammL respectively. The prevalance of high-level resistance to gentamicin and streptomycin were 96.9% and 78.1%, respectively. Prolonged hospital stay, cerebro-vascular disease, use of third generation cephalosporins, use of Foley catheter and levin tube were associated with VRE infection. 64 vanA VRE (61 E. faecium, 3 E. faecalis) had unique PFGE pattern within each hospital and showed no evidence of VRE transmission between hospitals. CONCLUSION: This study demonstrated the most common vancomycin resistance genotype among clini-cal VRE isolates in Korea were vanA type VRE. vanA genotype VRE had unique PFGE pattern within each hospital and showed no evidence of inter-hospital transmission. This study suggested that maintaining HICPAC guidelines, restricted vancomycin usage and periodic surveillance in patients with high risk factors are important in preventing the emergence and spread of VRE infection within hospitals.

Servey of HIV Exposure and Postexposure Prophylaxis among Health Care Workers in Korea / 병원감염관리

BACKGROUND: As of 30 September 2001, a total of 1,515 human immunodeficiency virus(HIV) infected persons has been reported in Korea. The number of newly infected persons tends to increase year by year, with the result that the contacts between HIV infected persons and health care workers (HCW) become more frequent. This survey was to investigate the current state of occupational HIV exposure and postexposure management among HCW in Korea. METHODS: We surveyed retrospectively the cases of occupational HIV exposure reported until the first half of 2001, in total 14 tertiary teaching hospitals. We reviewed these cases for the details about ; i) exposure type. medium and depth of injuty, ii) postexposure prophylaxis(PEP) and follow up serologic test and iii) source patients. RESULTS: Forty-eight cases(65% female, no pregnant woman) of occupational HIV exposure were identified. The number of cases tends to increase rapidly in recent two years. The majority of the exposure occurred in nurses and doctors, after percutaneous needle stick injury. The mean time from exposure to administration of PEP drugs was 20 hours. Of 39 cases receiving the PEP drug, 62% completed all of the drugs as initially prescribed and 31% discontinued all PEP drugs. The reasons for discontinuation included adverse events(9 cases), health care provider judgment(1case), and source patient HIV negative(1case). There was at least one adverse event in 59% of cases receiving the PEP drugs. The most frequent adverse events were gastrointestinal symptoms such as nausea. vomiting, anorexia, and indigestion. So far. there has been no HCW infected with HIV via occupational exposure. Conelusion: Although primary prevention remains the best strategy for protecting HCW from occupational HIV transmission, exposures are nevertheless likely to occur. Systematized PEP programs that include written protocols for prompt reporting, evaluation, counseling, treatment. and follow-up of occupational exposures will be needed for the secondary prevention.

Nationwide Questionnaire Survey for the Prevalence, Detection Methods, and Infection Control Program of VRE Among Hospitals / 감염

BACKGROUND: Vancomcyin-resistantenterococci (VRE) have been an important nosocomial pathogen in the 1990s. Recently, VRE have become an emerging nosocomial pathogen in Korea, but there have been no nationwide study about the status of VRE in Korea. This nationwide questionnaire survey was aimed to determine the prevalence of VRE, the appropriateness of detection method for VRE, and to evaluate the infection control program in hospitals of various size in Korea. METHODS: During 4 weeks (September 1 to October 1, 1999), a questionnaire surveillance study was conducted. We had sent the questionnaire to 200 large hospitals in Korea, which were distributed nationwide. Questionnaire included the prevalence of VRE within the hospital, the detection method for VRE, method of enterococci isolation, antibiotics-susceptibility test and infection control method of VRE. RESULTS: The response rate to questionnaire was 42%. The species identification of enterococci was capable in 62.3% but the accurate enterococcal speciation were capable in 18%. Appropriate antibiotic-susceptibility test were produced only in 6.5%. Total 746 VRE were detected in 42 hospitals during 1-year despite of low sensitivity of detection methods. VRE was noted in 54.4% of hospitals at least. The isolation programme of VRE infected patients was presented in 20.3%, regular surveillance of VRE in high-risk population was produced only in 16.5%. CONCLUSOIN: The prevalence of enterococci among microorganisms isolated from clinical specimens were increased up to 27.7% in Korea. VRE has been emerged in many big cities as well as in Seoul. The microbiological methods that include the speciation of enterococcal isolates, antimicrobial susceptibility test, and VRE detection appeared to be inappropriate in many hospitals. And, proper control and prevention methods were presented in a few hospitals. Education and training about accurate detection of VRE as well as proper infection control programs for VRE are urgently needed.

Clinical and Genetic Characteristics of Infection by Penicillin-resistant Streptococcus pneumoniae from Community and Hospital / 감염

BACKGROUND: During the last three decades, the resistance of S. pneumoniae to penicillin has been rapidly increasing in many parts of the world, especially in Korea. To characterize the clinical features and epidemiology of penicillin-resistant S. pneumoniae (PRSP) infections in the community and hospital, as well as to investigate the possible spread of resistant clone, we performed the antimicrobial susceptibility tests, pulsed filed gel electrophoresis (PFGE) and penicillin-binding protein (PBP) profile analysis of PRSP isolates. METHODS: A total 48 PRSP isolates from patients who visited or were admitted to Korea University Guro hospital during the period form July 1998 to June 1999 were studied. Anitimicrobial susceptibility tests for 48 isolates were performed with microbroth dilution method to determine the minimal inhibitory concentration of 11 antibiotics. 39 isolates and 35 isolates were subjected to PFGE and PBP profile analysis, respectively to investigate the genetic relatedness between PRSP isolates. RESULTS: Pneumonia was most common site of infection in the community and the hospital as 50%. There were no significant differences of clinical features and prognosis between community and hospital isolates. But, patients with serious underlying diseases had poor prognosis despite of acquisition site. High level penicillin resistance were observed in 69%, multi-drug resistance were 64.6% of isolates. PFGE showed that 13 of 29 community acquired infection were identical PFGE pattern but not that of 23F Spanish clone. There were various PFGE patterns were observed from community and hospital acquired infection isolates. Some of them were existed in both. PBP profiles showed more diverse, even if in isoaltes of the same PFGE pattern. CONCLUSOIN: In our study, high level penicillin resistance and multi-drug resistance were observed in PRSP clinical isolates. No clinical and prognostic differeces were observed between community and hospital acquired infections. Molecular epidemiology study were suggest the there were various genotypes of PRSP within our society. Some of them were observed in the hospital and community. Therefore, there was an evidence of communication of PRSP clones between the community and hospital.

A Longitudinal Molecular Epidemiologic Study of Methicillin-resistant Staphylococcus aureus (MRSA) Isolates from a University Hospital / 감염

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important nosocomial pathogens and establishs the endemicity within many large hospitals in Korea. The identification and eradication of infection source is essential to prevent and control the spread of MRSA infection. So it is necessary to know how many MRSA clones have existed and how these clones have changed. The aim of this study is to determine the molecular epidemiology of MRSA over a 8-years period from 1991 to 1998 by using pulsed-field gel electrophoresis (PFGE) typing method in a university hospital. METHODS: MRSA isolates from various clinical specimens were collected during 8 years from 1991 to 1998 in Korea University Guro Hospital. The identification of S. aureus was done by catalase and coagulase test. Methicillin resistance was tested by oxacillin disk diffusion method. Pulsed field gel electrophoresis (PFGE) using SmaI was performed for molecular typing. We determined the clonality of MRSA strains by dendrogam analysis. RESULTS: One hundred four MRSA isolates were collected from clinical specimens. PFGE typing showed 8 types and 13 subtypes totally. Type A and type B were the major clonal strains, which comprized of 41.3% (43 strains) and 37.5% (39 strains), respectively, and other types were isolated in small numbers. In 1991, type A and type B were encountered in 36.8% (7/19) each, respectively. In 1994, type A was 65.2% (15/23) and type B was 21.7% (5/23). In 1998, type A was 75.0%(18/24) and type B was 4.2%(1/24). Total types and subtypes according to years were 4 types and 6 subtypes in 1991, 5 types and 6 subtypes in 1992, 4 types and 4 subtypes in 1993, 4 types and 6 subtypes in 1994 and 4 types and 7 subtypes in 1998, respectively. CONCLUSION: The diversity of MRSA strains were observed over 8 years. Type A and type B have been isolated as dominant clones in a university hospital during 8 years. It is presumed that they have isolated from clinical specimens continuously and established the endemicity in this hospital. So it is necessary to prevent the spread of dominant clones intensively, to study the difference of virulence between the dominant and minor clones, and to determine the introduction and spread of MRSA from the community and other hospitals. The PFGE technique was a useful epidemiologic tool for tracking and typing the MRSA isolates.