agr functionality affects clinical outcomes in patients with persistent methicillin-resistant Staphylococcus aureus bacteraemia.

Methicillin-resistant Staphylococcus aureus bacteremia (MRSAB) often persists despite appropriate antibiotic therapy. It is unclear what microbiological factors contribute to poor clinical outcomes in persistent MRSAB (pMRSAB). We aimed to identify clinical and microbiological risk factors for in-hospital mortality in pMRSAB. We analysed MRSAB cases prospectively collected between 2009 and 2016 at 11 hospitals in Korea, defining cases of pMRSAB as MRSAB lasting ≥5 days despite administration of effective antibiotics. The first blood isolates from the pMRSAB cases were tested for staphylococcal cassette chromosome mec type, staphylococcal protein A type, accessary gene regulator (agr) type, genes for Panton-Valentine leukocidin and phenol-soluble modulin-mec, vancomycin minimum inhibitory concentration, vancomycin heteroresistance, and agr functionality. We also collected clinical information for each case. Of 960 MRSAB cases, 152 pMRSAB were finally eligible. Univariable analysis revealed that in-hospital mortality was significantly associated with Charlson's comorbidity-weighted index (CCWI) score, Pitt bacteremia score, sequential organ failure assessment score, presentation with septic shock, pneumonia, agr dysfunction, and vancomycin heteroresistance. Bone and joint infections were negatively associated with in-hospital mortality. Multivariable analysis revealed the following independent risk factors for in-hospital mortality: CCWI score [adjusted odds ratio (aOR), per one point, 1.25; 95% confidence interval (CI), 1.08-1.44; P = 0.003), Pitt bacteremia score (aOR, per one point, 1.33; 95% CI, 1.09-1.62; P = 0.005), non-eradicated foci of infection (aOR, 3.12; 95% CI, 1.18-8.27; P = 0.022), and agr dysfunction (aOR, 2.48; 95% CI, 1.12-5.47; P = 0.025). agr dysfunction is an independent risk factor for in-hospital mortality in pMRSAB.

Disease burden of bacteraemia with extended-spectrum beta-lactamase-producing and carbapenem-resistant Enterobacterales in Korea.

BACKGROUND: Despite the significant impact of multi-drug-resistant bacteraemia, especially extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) and carbapenem-resistant Enterobacterales (CRE), the burden of disease has not been investigated thoroughly. AIM: To evaluate the clinical outcomes and socio-economic burden of ESBL-E and CRE bacteraemia nationwide in the Republic of Korea. METHODS: A search was undertaken for all cases of ESBL-E and CRE bacteraemia and matched controls in 10 hospitals in the Republic of Korea over 6 months. Patients with ESBL-E or CRE bacteraemia were classified as the R group, and matched controls with antibiotic-susceptible bacteraemia and without infection were classified as the S and N groups, respectively. Patients' clinical data were collected, and the economic burden was estimated based on medical expenses, loss of productivity and total costs. FINDINGS: In total, 795 patients were identified, including 265 patients with ESBL-E or CRE bacteraemia and their matched controls. The mean total length of stay for patients with ESBL-E and CRE in the R group was 1.53 and 1.90 times that of patients in the S group, respectively. The 90-day mortality rates for ESBL-E in the R and S groups were 12.1% and 5.6%, respectively, and the corresponding figures for CRE were 28.6% and 12.0%. There were significant differences in the total costs between the R, S and N groups for both ESBL-E and CRE (ESBL-E: $11,151 vs $8712 vs $6063, P=0.004; CRE: $40,464 vs $8748 vs $7279, P=0.024). CONCLUSION: The clinical and economic burden imposed by ESBL-E or CRE bacteraemia was extremely high. These findings suggest that efforts to control resistant bacteraemia are necessary to reduce this burden.

Impact of discontinuing isolation in a private room for patients infected or colonized with vancomycin-resistant enterococci (VRE) on the incidence of healthcare-associated VRE bacteraemia in a hospital with a predominantly shared-room setting.

BACKGROUND: Isolating patients infected or colonized with vancomycin-resistant enterococci (VRE) in a private room or cohort room to prevent hospital transmission is controversial. AIM: To evaluate the effect of a relaxed isolation policy for VRE-infected or colonized patients on healthcare-associated (HA) VRE bacteraemia in an acute care hospital with a predominantly shared-room setting. METHODS: The incidence of HA VRE bacteraemia was compared during a private isolation era (October 2014-September 2017), a cohort isolation era (October 2017-June 2020), and a no isolation era (July 2020-June 2022). Using Poisson regression modelling, an interrupted time-series analysis was conducted to analyse level changes and trends in incidences of HA VRE bacteraemia for each era. FINDINGS: The proportion of VRE-infected or -colonized patients staying in shared rooms increased from 18.3% in the private isolation era to 82.6% in the no isolation era (P < 0.001). There was no significant difference in the incidences of HA VRE bacteraemia between the private isolation era and the cohort isolation era (relative risk: 1.01; 95% confidence interval: 0.52-1.98; P = 0.977) or between the cohort isolation era and the no isolation era (0.99; 0.77-1.26; P = 0.903). In addition, there was no significant slope increase in the incidence of HA VRE bacteraemia between any of the eras. CONCLUSION: In a hospital with predominantly shared rooms, the relaxation of isolation policy did not result in increased HA VRE bacteraemia, when other infection control measures were maintained.

Risk factors for 30-day mortality in adult patients with pneumococcal bacteraemia, and the impact of antimicrobial resistance on clinical outcomes.

The clinical impact of antimicrobial resistance on the outcome of pneumococcal bacteraemia has remained unclear. This study aimed to evaluate risk factors for mortality and determine the impact of antimicrobial resistance on clinical outcomes. A total of 150 adult patients with pneumococcal bacteraemia were identified over a period of 11 years at Seoul National University Hospital. Of the 150 patients, 122 (81.3%) had penicillin-susceptible (Pen-S) strains and 28 (18.7%) penicillin-non-susceptible (Pen-NS) strains; 43 (28.7%) had erythromycin-susceptible (EM-S) strains and 107 (71.3%) erythromycin-non-susceptible (EM-NS) strains. On multivariate analysis, elevated APACHE II score [odds ratio (OR) 1.24, 95% confidence interval (CI) 1.14-1.34, P<0.001) and presence of solid organ tumour (OR 2.99, 95% CI 1.15-7.80, P=0.025) were independent risk factors for mortality. Neither erythromycin resistance nor penicillin resistance had a significant effect on clinical outcomes. However, for the 76 patients with pneumococcal pneumonia, the time required for defervescence was significantly longer in the EM-NS group than in the EM-S group (5.45 ± 4.39 vs. 2.93 ± 2.56, P=0.03 by log rank test). In conclusion, antimicrobial resistance does not have an effect on mortality in adult patients with pneumococcal bacteraemia.

Reduction in the acquisition rate of carbapenem-resistant Acinetobacter baumannii (CRAB) after room privatization in an intensive care unit.

BACKGROUND: Acinetobacter baumannii is one of the major pathogens responsible for healthcare-associated infections, especially in intensive care units (ICUs). AIM: To evaluate the effect of room privatization in an ICU on the acquisition of carbapenem-resistant A. baumannii (CRAB). METHODS: Between March and August 2017, a medical ICU was renovated from a multi-bed bay room to single rooms. Acquisition of CRAB was compared between patients admitted to the ICU over 18 months pre-renovation (September 2015 to February 2017) and post-renovation (September 2017 to February 2019). A Cox proportional hazard model was used with adjustment for demographics and comorbidities. FINDINGS: Of the 901 patients, who contributed 8276 patient-days, 95 (10.5%) acquired CRAB during their ICU stay. The CRAB acquisition rate was significantly higher during the pre-renovation period (1.87 per 100 patient-days) than during the post-renovation period (0.39 per 100 patient-days) (P<0.001). In the multi-variable Cox regression model, CRAB acquisition was significantly associated with the presence of a feeding tube (adjusted hazard ratio (aHR), 6.08; 95% confidence interval (CI), 2.46-15.06; P<0.001), continuous renal replacement therapy (aHR, 1.66; 95% CI, 1.09-2.53; P=0.019) and admission after renovation of the ICU to single rooms (aHR, 0.23; 95% CI, 0.12-0.41; P<0.001). CONCLUSIONS: Renovation of ICUs to single rooms is an efficient strategy to prevent transmission of multi-drug-resistant organisms and hospital-acquired infections.

Investigation on the transmission rate of carbapenemase-producing carbapenem-resistant Enterobacterales among exposed persons in a tertiary hospital using whole-genome sequencing.

BACKGROUND: To reduce transmission of carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE), screening is recommended for patients sharing rooms with CP-CRE-detected patients and healthcare workers caring for them. AIM: The aim of this study was to investigate the transmission rate of CP-CRE among exposed people in a tertiary hospital using whole-genome sequencing. METHODS: This study was conducted in a 1751-bed tertiary teaching hospital from January 2017 to December 2019. Index patients were defined as those with positive results in CP-CRE tests during hospitalization. When an index patient was detected in a shared room, we performed CRE screening tests for patients whose stay overlapped with an index patient's stay for at least one day. Where a second case was found, healthcare worker contacts were also screened. CP-CRE were confirmed, and the carbapenemase type identified, by PCR. Whole-genome sequencing was used to compare isolates from index and exposed patients. RESULTS: During the study period, 47 index patients were identified, and they had been in contact with 152 patients in shared rooms and 54 healthcare workers. None of the healthcare workers had CRE. Among the 152 exposed patients, four patients had the same type of carbapenemases as their CP-CRE index patients and all of them were KPC. Whole-genome sequencing revealed that three of these four pairs showed genotypic accordance between the index and the exposed. CONCLUSION: The CP-CRE transmission rate among the exposed patients was calculated as 2.0% (= 3/152).

One-step lateral window approach for removal of benign minor sinus pathologies combined with transcrestal sinus floor elevation without bone grafts: a retrospective study.

The aim of this study was to evaluate the clinical and radiographic outcomes of a lateral window approach for removal of benign minor sinus pathologies combined with transcrestal sinus floor elevation. From 2014 to 2018, all patients who received sinus pathology removal via a lateral window approach combined with transcrestal sinus floor elevation were screened. The serous exudate or minor sinus pathology was drained or removed via lateral window approach. Subsequently, transcrestal sinus floor elevation without grafting and simultaneous implant placement were performed. Panoramic radiographs and cone-beam computed tomography were taken preoperatively, immediately after surgery, and after prosthesis delivery. Twelve patients were included in this study. The decrease in Schneiderian membrane thickness was statistically significant (P<0.001). Endo-sinus bone formation was observed on the buccal (1.35±2.31mm) and palatal (1.61±2.65mm) sites of the implant. The implant survival rate was 100%. All implants survived for an average of 21.83±11.11 months. Within the limitations of this study, we suggest that the lateral window approach for minor sinus pathology removal combined with transcrestal sinus floor elevation has several advantages including endo-sinus bone gain without bone graft, minimal patient discomfort, reduced postoperative complications and shorter treatment period.

Risk factors for the delayed diagnosis of extrapulmonary TB.

BACKGROUND: Extrapulmonary TB (EPTB) is more difficult to diagnose than pulmonary TB. The delayed management of EPTB can lead to complications and increase the socio-economic burden.METHODS: Patients newly diagnosed with EPTB were retrospectively enrolled from 11 general hospitals in South Korea from January 2017 to December 2018. The basic characteristics of patients were described. Univariable and multivariable analyses were performed between early and delayed diagnosis groups to identify risk factors for delayed diagnosis and treatment in EPTB.RESULTS: In total, 594 patients were enrolled. Lymph node TB (28.3%) was the predominant form, followed by abdominal (18.4%) and disseminated TB (14.5%). Concurrent lung involvement was 17.8%. The positivity of diagnostic tests showed no significant difference between the two groups. Acute clinical manifestations in disseminated, pericardial and meningeal TB, and immunosuppression were associated with early diagnosis. Delayed diagnosis was associated with outpatient clinic visits, delayed sample acquisition and diagnostic departments other than infection or pulmonology.CONCLUSION: The delay in diagnosis and treatment of EPTB was not related to differences in microbiological characteristics of Mycobacterium tuberculosis itself; rather, it was due to the indolent clinical manifestations that cause referral to non-TB-specialised departments in the outpatient clinic and delay the suspicion of TB and diagnostic testing.

Enhanced antimicrobial stewardship based on rapid phenotypic antimicrobial susceptibility testing for bacteraemia in patients with haematological malignancies: a randomized controlled trial.

OBJECTIVES: Recently, rapid phenotypic antimicrobial susceptibility testing (AST) based on microscopic imaging analysis has been developed. The aim of this study was to determine whether implementation of antimicrobial stewardship programmes (ASP) based on rapid phenotypic AST can increase the proportion of patients with haematological malignancies who receive optimal targeted antibiotics during early periods of bacteraemia. METHODS: This randomized controlled trial enrolled patients with haematological malignancies and at least one positive blood culture. Patients were randomly assigned 1:1 to conventional (n = 60) or rapid phenotypic (n = 56) AST. The primary outcome was the proportion of patients receiving optimal targeted antibiotics 72 hr after blood collection for culture. RESULTS: The percentage receiving optimal targeted antibiotics at 72 hr was significantly higher in the rapid phenotypic AST group (45/56, 80.4%) than in conventional AST group (34/60, 56.7%) (relative risk (RR) 1.42, 95% confidence interval (CI) 1.09-1.83). The percentage receiving unnecessary broad-spectrum antibiotics at 72 hr was significantly lower (7/26, 12.5% vs 18/60, 30.0%; RR 0.42, 95% CI 0.19-0.92) and the mean time to optimal targeted antibiotic treatment was significantly shorter (38.1, standard deviation (SD) 38.2 vs 72.8, SD 93.0 hr; p < 0.001) in the rapid phenotypic AST group. The mean time from blood collection to the AST result was significantly shorter in the rapid phenotypic AST group (48.3, SD 17.6 vs 83.1, SD 22.2 hr). DISCUSSION: ASP based on rapid phenotypic AST can rapidly optimize antibiotic treatment for bacteraemia in patients with haematological malignancy. Rapid phenotypic AST can improve antimicrobial stewardship in immunocompromised patients.

Active surveillance for carbapenem-resistant Enterobacteriaceae, vancomycin-resistant enterococci and toxigenic Clostridium difficile among patients transferred from long-term care facilities in Korea.

A 10-month active surveillance study was conducted to assess carriage of carbapenemase-producing Enterobacteriaceae (CPE), vancomycin-resistant enterococci (VRE) and toxigenic Clostridium difficile colonization among patients transferred to hospital from long-term care facilities (LTCFs). Four (1.4%) patients with carbapenem-resistant Enterobacteriaceae (none of which were CPE), 59 (21%) patients with VRE and 20 (7.1%) patients colonized with toxigenic C. difficile were identified from 282 rectal specimens. There was no outbreak of VRE infection during the study period. The low prevalence of CPE carriage suggests that screening all admissions from LTCFs for CPE would not be cost-effective, and that screening and use of contact precautions for VRE should be reconsidered.

Comparative outcomes of cefazolin versus nafcillin for methicillin-susceptible Staphylococcus aureus bacteraemia: a prospective multicentre cohort study in Korea.

OBJECTIVES: No randomized controlled trials have evaluated the comparative outcomes of cefazolin versus nafcillin for methicillin-susceptible Staphylococcus aureus (MSSA) bacteraemia. METHODS: A prospective observational cohort study including all S. aureus bacteraemia was conducted at 10 hospitals. Patients (≥15 years) with MSSA bacteraemia who received cefazolin or nafcillin as definitive antibiotics were included. The rates of treatment failure (premature discontinuation of antibiotics because of adverse effects, switching of antibiotics because of clinical failure, all-cause mortality within 1 month, or recurrence) were compared between the cefazolin and nafcillin groups. Propensity score matching analyses were performed to balance the factors influencing the selection of antibiotics. RESULTS: Among the 242 included cases, the bones and joints (36.8%) were the most common sites of infection and 60.7% of the patients had sepsis. The overall treatment failure rate was 43.8% (106/242). All-cause mortality within 1 month was 6.2% (15/242). After propensity score matching, the treatment failure rate of cefazolin was lower than that of nafcillin (30.4% (24/79) vs. 49.4% (39/79), p 0.015) because of a higher rate of discontinuation caused by adverse events. When the data were limited to patients with sepsis, the treatment failure rates of both groups were not significantly different. Approximately 22% (24/110) of MSSA isolates exhibited a cefazolin-inoculum effect (CIE) that had significant impact on the failure rate and mortality of the cefazolin group. CONCLUSIONS: Cefazolin might be recommended as an adequate and better-tolerated treatment for MSSA bacteraemia in the absence of CIE.

Risk factors for suboptimal drug concentration of posaconazole oral suspension in patients with hematologic malignancy.

Absorption of posaconazole oral suspension is influenced by several factors including diet, medications, and mucosal integrity. However, there are few prospective data about which is the most important modifiable factor in routine clinical practice. We prospectively analyzed clinical risk factors associated with low posaconazole trough concentrations in 114 patients receiving anticancer chemotherapy due to acute myeloid leukemia or myelodysplastic syndrome who received posaconazole oral suspension. In multivariate analyses, risk factors for drug level<500ng/mL included low calorie intake, mucositis≥grade 2, H2 blocker famotidine and proton-pump inhibitor. The only significant risk factor for drug level<700ng/mL was famotidine use (adjusted relative risk, 3.18; 95% confidence interval, 1.07-9.11; P=0.038). In conclusion, medication of H2 blocker famotidine should be cautious in patients with hematologic malignancy receiving posaconazole suspension.

Outcome of inappropriate empirical antibiotic therapy in patients with Staphylococcus aureus bacteraemia: analytical strategy using propensity scores.

Patients with Staphylococcus aureus bacteraemia (SAB) who received either inappropriate or appropriate empirical therapy were compared by using two risk stratification models: (1) a cohort study using a propensity score to adjust for confounding by empirical treatment assignment; and (2) a propensity-matched case-control study. Inappropriate empirical therapy was modelled on the basis of patient characteristics, and included in the multivariate model to adjust for confounding. For case-matching analysis, patients with inappropriate empirical therapy (cases) were matched to those with appropriate empirical therapy (controls) on the basis of the propensity score (within 0.03 on a scale of 0-1). In total, 238 patients with SAB were enrolled in the cohort study. Characteristics associated with inappropriate empirical therapy were methicillin resistance, underlying haematological malignancy, no history of colonisation with methicillin-resistant S. aureus, and a long hospital stay before SAB. These variables were included in the propensity score, which had an area under the receiver operating characteristics curve of 85%. In the cohort study, SAB-related mortality was 39% (45/117) for inappropriate empirical therapy vs. 28% (34/121) for appropriate empirical therapy (odds ratio (OR) 1.60; 95% CI 0.93-2.76). After adjustment for independent predictors for mortality and the propensity score, inappropriate empirical therapy was not associated with mortality (adjusted OR 1.39; 95% CI 0.62-3.15). In the matched case-control study (50 pairs), SAB-related mortality was 32% (16/50) for inappropriate empirical therapy and 28% (14/50) for appropriate empirical therapy (McNemar's test; p 0.85; OR 1.15; 95% CI 0.51-2.64). In conclusion, inappropriate empirical therapy resulted in only a slight tendency towards increased mortality in patients with SAB.

Clinical features and outcome of patients with community-acquired Pseudomonas aeruginosa bacteraemia.

Cases of community-acquired Pseudomonas aeruginosa bacteraemia (n = 39) that occurred at a tertiary-care hospital during a 5-year period were analysed retrospectively. The commonest underlying diseases were solid tumour (41%) and haematological malignancy (18%). Most (44%) of the patients were neutropenic, and 39% had septic shock at initial presentation. The 30-day attributable mortality rate was 39%. Two previously healthy patients were identified with fatal P. aeruginosa pneumonia with bacteraemia. P. aeruginosa bacteraemia is a fatal infection that should be considered in the differential diagnosis of patients presenting from the community with rapidly progressive sepsis.

Educational intervention as an effective step for reducing blood culture contamination: a prospective cohort study.

BACKGROUND: Contaminated blood cultures lead to diagnostic challenges and place a burden on healthcare services. AIM: To determine the impact of introducing a clinical skills test (CST) as part of the medical licensing examination and an institutional education programme on the contamination rates of blood cultures. METHODS: A prospective cohort study was conducted from 2009 through 2013 in all wards of a tertiary-care teaching hospital. We evaluated the effects of the CST, which was added to the National Medical Licensing Examination in Korea (KMLE) in 2010 and our institutional education programme, which began in 2013. The medical interns in charge of collection of blood for culture were divided in three groups with presence or absence of CST and the institutional education programme. The primary outcome was the percentage of blood cultures contaminated in each group, which were compared using the Poisson regression model. Participants' self-rated scores for the blood draw procedure were also analysed. FINDINGS: Although introduction of the CST in the KMLE failed to reduce blood culture contamination rate (1.36% vs 1.35%; P = 0.734), the institutional education programme significantly reduced the contamination rate (1.35% vs 1.00%; P < 0.0001). Most participants answered that they always followed each step correctly except for waiting the recommended contact time after applying the antiseptic. CONCLUSION: The educational intervention, not the introduction of CST in the KMLE, was effective in reducing overall contamination rates.

Which tissues are best for microbiological diagnosis in patients with pyogenic vertebral osteomyelitis undergoing needle biopsy?

Identification of the causative microorganism is important in the management of pyogenic vertebral osteomyelitis (PVO). The aim of this study was to investigate whether culture positive rates differ between needle biopsy sites in patients with PVO, and which tissues are best for microbiological diagnosis. Between January 2005 and December 2013, we conducted a retrospective cohort study of PVO patients who had soft-tissue abscesses (paraspinal or psoas abscesses) and who received needle biopsy for microbiological diagnosis. Needle biopsy sites were classified into two anatomical categories: vertebral bodies, or soft tissues (intervertebral discs, paraspinal abscesses, or psoas abscesses). A generalized estimating equation model was developed to identify factors associated with tissue-culture positivity. During the study period a total of 136 tissues were obtained by needle biopsy from 128 PVO patients with soft-tissue abscesses. The culture positive rates of vertebral bodies and soft tissues were 39.7% (29/73), and 63.5% (40/63), respectively (p < 0.05). In a multivariate analysis, male gender (adjusted odds ratio (aOR) 2.24, 95% CI 1.00-5.02), higher C-reactive protein (aOR 1.07, 95% CI 1.01-1.15), positive blood culture (aOR 2.57, 95% CI 1.01-6.59), and soft tissues as biopsy site compared with vertebral bodies (aOR 2.28, 95% CI 1.08-4.78) were independent factors associated with tissue culture positivity. Soft tissues were the best sites for microbiological diagnosis in PVO patients undergoing needle biopsy.

Inhibition of tumor growth and metastasis by Korean mistletoe lectin is associated with apoptosis and antiangiogenesis.

The mistletoe lectins are major active components in the extract of European mistletoes that have been widely used in adjuvant chemotherapy of cancer. This study was performed to investigate the mechanism of anticancer and antimetastatic activity of the purified Korean mistletoe lectin (Viscum album L. coloratum agglutinin, VCA). C57BL6 mice inoculated with B16-BL6 melanoma cells and treated with VCA were assessed for survival and metastasis. The induction of apoptosis of B16-BL6 cells by VCA was investigated by morphological changes, DNA fragmentation characteristics, and cell cycle analysis. The antiangiogenic activity of VCA was also measured by the CAM (choriallantoic membrane) assay. Length of survival of mice was increased and lung metastasis was inhibited by VCA. Treatment of cells with VCA resulted in growth suppression, nuclear morphological changes, DNA fragmentation, and an increased fraction of cells in sub-G1 consistent with apoptosis. Antiangiogenesis of VCA was assessed by CAM assay, where vessel growth induced by fat emulsion was decreased. These results suggest that VCA inhibits tumor growth and metastasis by increasing apoptosis and inhibiting angiogenesis.

Dissociation and complexation of fluoroquinolone analogues.

The dissociation and the complexation behaviours of four fluoroquinolone antibiotics have been studied. The acid dissociation constants of ciprofloxacin, enoxacin, norfloxacin and ofloxacin were determined by conventional potentiometric and conductometric techniques. Increasing the Hammett substituent constant, the pKa values were decreased. The absorption of fluoroquinolones in the intestinal tract are probably transported by pH-dependent mechanisms. Formation constants of the iron(III) complexes (1:1) of the fluoroquinolone analogues were determined by spectrophotometry. The optimum pH for complexation was 3.80.

Isolation and characterization of beta-galactoside specific lectin from Korean mistletoe (Viscum album var. coloratum) with lactose-BSA-sepharose 4B and changes of lectin conformation.

Lectins and its A- and B-chains from Korean mistletoe (Viscum album var. coloratum) were isolated by affinity chromatography on the Sepharose 4B modified by lactose-BSA conjugate synthesized by reductive amination of ligand (lactose) to epsilon-amino groups of lysine residues of spacer (BSA) after reduction by NaCNBH3. The lactose-BSA conjugate was coupled to Sepharose 4B activated by cyanogen bromide. The molecular weight determined by SDS-PAGE were a 31 kD of A-chain and a 35 kD of B-chain. Amino acid analysis and N-terminal sequencing were performed. The effects of pH, temperature and guanidine chloride on the conformation of the lectin were investigated by measuring its intrinsic fluorescence and compared with its hemagglutinating activities. Blue shift was detected on the acidic pH and there was a close relationship between activities and conformation of the lectin. Under denaturing conditions, the tryptophan emission profile of lectin showed typical denaturational red shift which also correspond to the conformations and activity of lectin.