Here we discuss whether N terminal sequencing is appropriate as one of the conventional control methods for monoclonal antibody products. We determined the N terminal sequences of two monoclonal antibody products targeting two antigens separately with both Edman degradation and mass peptide spectrometry. We also identified the characteristic peptide fragments with mass spectrometry. Furthermore, we analyzed their heterogeneity with ion exchange chromatography, capillary zone electrophoresis and Imaged Capillary Isoelectric Focusing. Edman degradation method showed that the N terminal 15 amino acids of heavy and light chains of the two monoclonal antibodies were identical. Peptide mass spectrometry demonstrated that T1 peptide fragments of heavy and light chains of the two antibodies were also the same. But in contrast, peptide mapping and the three analytical methods for heterogeneity analysis could effectively identify and differentiate the two antibodies. The N terminal sequences of two monoclonal antibodies are identical because the number of framework sequences of humanized or human monoclonal antibodies is relatively limited, so whether N terminal sequencing analysis could be regulated as one of the practical control methods should be carefully discussed. Our work also proves that the above analytical methods could combinatorially applied to the identification of monoclonal antibody products, and are more objective compared to N terminal sequencing.
Amino Acid Sequence ; Antibodies, Monoclonal ; isolation & purification ; Chromatography, Ion Exchange ; Humans ; Isoelectric Focusing ; Mass Spectrometry ; Peptide Mapping ; Peptides ; Sequence Analysis, Protein ; methods

BACKGROUNDThe rise of the production of CTX-M class extended spectrum β-lactamases (ESBLs) has been well documented in traveling countries but no data are found for Macao, an international travel city. The objectives of this study were to identify the antimicrobial resistance pattern, and determine the prevalence, genotype and clonal relationship of ESBLs in 209 clinical Escherichia coli strains from Macao, China.

METHODSAntimicrobial susceptibility test was performed to determine the resistance patterns of the isolates using the disk diffusion method with 17 antimicrobial agents. Phenotypic detection was screened and confirmed according to the Clinical and Laboratory Standards Institute. Genotypic characterization was detected by isoelectric focusing analysis, polymerase chain reaction and sequencing. The clonal relationship between the different ESBL isolates was studied by pulsed-field gel electrophoresis (PFGE).

RESULTSImipenem and meropenem exhibited 100% susceptible among 209 strains. Overall, 82.3%, 67.3%, 52.9%, 51.2% and 51.0% of the isolates displayed resistance to ampicillin, tetracycline, ciprofloxacin, sulfamethoxazole trimethoprim and gentamycin. The prevalence rate of ESBLs was 30.1%. Antibiotic resistances were found to be significantly higher among the ESBL producing group compared to non-ESBL producing group. We detected CTX-M-14 to be the major genotypic characterization of ESBLs (76.2%). Two strains showed indistinguishable patterns by PFGE.

CONCLUSIONSThe prevalence of antimicrobial resistance is alarming high in Macao. Antimicrobial resistance is significantly higher among the ESBL producing group. This study documented CTX-M-14 as the predominant ESBL type. Although indistinguishable pattern was found between two strains, it was too small to decide whether any of the investigated strains was epidemic. Our findings may be also pertinent for other geographic areas undergoing similar travel characteristics to understand the corresponding effects on bacterial populations.

Anti-Infective Agents ; pharmacology ; China ; Drug Resistance, Microbial ; genetics ; Electrophoresis, Gel, Pulsed-Field ; methods ; Escherichia coli ; drug effects ; enzymology ; genetics ; Genotype ; Isoelectric Focusing ; Macau ; beta-Lactamases ; genetics ; metabolism

In the present study, isoelectronic focusing with different pH gradients (pH 3-5, 2-6) or migrating distances (8.5, 12 and 17 cm) and SDS-PAGE was used to separate continuous erythropoietin receptor activator (CERA), recombinant human erythropoietin (rhEPO), darbepoetin and endogenous EPO spiked in human urine with 37 degrees C overnight incubation. Double blotting and chemiluminescent visualization were used to detect the IEF and SDS-PAGE profiles. The bands of CERA profile were detected and well separated from the endogenous EPO and the other two EPO preparations with both SDS-PAGE and the IEF method using a gradient pH 3-5 and a migrating distance of 17 cm, and a significant particular band of CERA profile was found in the IEF result. These preliminary results indicated that the methods were reliable and reproducible for detecting CERA, and could be used as a routine procedure for anti-doping analysis.
Electrophoresis, Polyacrylamide Gel ; Erythropoietin ; urine ; Humans ; Isoelectric Focusing ; methods ; Polyethylene Glycols ; Recombinant Proteins

BACKGROUND: Extended-spectrum cephalosporins (ESCs)-resistant Enterobacter cloacae is one of the pathogens of nosocomial infection the incidence of which is on the rise. Moreover, plasmid-mediated quinolone resistance genes (PMQR genes) that reduce quinolone sensitivity have been shown to be widely distributed among clinical isolates of Enterobacteriaceae. This study was carried out to observe the distribution of PMQR genes in clinical isolates of E. cloacae resistant to ESCs. MATERIALS AND METHODS: Fourty-three ESCs-resistant E. cloacae strains from the blood collected during the span of 7 years, from 1994 to 2001, at Seoul National University Children's Hospital (SNUCH) were included in this study. Isoelectric focusing and enzyme specific PCR were performed to characterize beta-lactamase. The presence of qnrA, qnrB, qnrC, qnrS, qepA, and aac(6')-Ib-cr was determined by PCR, restriction enzyme analyses of PCR products, and DNA sequencing. Minimal inhibitory concentration (MIC) of several quinolones was measured by agar dilution method. RESULTS: The PMQR genes were detected in 9 (21%) of 43 ESCs-resistant E. cloacae isolates. Among them, five isolates were positive for qnrB2, and each two isolates harbored qnrB4 or qnrB5, respectively. qnrA, qnrC, qnrS or qepA was not identified. aac(6')-Ib was detected in 27 isolates, but aac(6')-Ib-cr was not found. Among the 9 qnrB-positive isolates, 5 produced SHV-12, 3 were derepressed mutants, and 1 produced pI 7.5 beta-lactamase. MIC ranges and percent resistances of nalidixic acid, ofloxacin, levofloxacin, and moxifloxacin for the PMQR genes-positive isolates were higher than PMQR genes-negative isolates. CONCLUSION: In this study, ESCs-resistant E. cloacae showed a high prevalence of PMQR genes, and qnrB was the only PMQR gene identified.
Agar ; Aza Compounds ; beta-Lactamases ; Cephalosporins ; Cloaca ; Cross Infection ; Enterobacter ; Enterobacter cloacae ; Enterobacteriaceae ; Incidence ; Isoelectric Focusing ; Nalidixic Acid ; Ofloxacin ; Polymerase Chain Reaction ; Prevalence ; Quinolines ; Quinolones ; Restriction Mapping ; Sequence Analysis, DNA

BACKGROUND: Extended-spectrum cephalosporins (ESCs)-resistant Enterobacter cloacae is one of the pathogens of nosocomial infection the incidence of which is on the rise. Moreover, plasmid-mediated quinolone resistance genes (PMQR genes) that reduce quinolone sensitivity have been shown to be widely distributed among clinical isolates of Enterobacteriaceae. This study was carried out to observe the distribution of PMQR genes in clinical isolates of E. cloacae resistant to ESCs. MATERIALS AND METHODS: Fourty-three ESCs-resistant E. cloacae strains from the blood collected during the span of 7 years, from 1994 to 2001, at Seoul National University Children's Hospital (SNUCH) were included in this study. Isoelectric focusing and enzyme specific PCR were performed to characterize beta-lactamase. The presence of qnrA, qnrB, qnrC, qnrS, qepA, and aac(6')-Ib-cr was determined by PCR, restriction enzyme analyses of PCR products, and DNA sequencing. Minimal inhibitory concentration (MIC) of several quinolones was measured by agar dilution method. RESULTS: The PMQR genes were detected in 9 (21%) of 43 ESCs-resistant E. cloacae isolates. Among them, five isolates were positive for qnrB2, and each two isolates harbored qnrB4 or qnrB5, respectively. qnrA, qnrC, qnrS or qepA was not identified. aac(6')-Ib was detected in 27 isolates, but aac(6')-Ib-cr was not found. Among the 9 qnrB-positive isolates, 5 produced SHV-12, 3 were derepressed mutants, and 1 produced pI 7.5 beta-lactamase. MIC ranges and percent resistances of nalidixic acid, ofloxacin, levofloxacin, and moxifloxacin for the PMQR genes-positive isolates were higher than PMQR genes-negative isolates. CONCLUSION: In this study, ESCs-resistant E. cloacae showed a high prevalence of PMQR genes, and qnrB was the only PMQR gene identified.
Agar ; Aza Compounds ; beta-Lactamases ; Cephalosporins ; Cloaca ; Cross Infection ; Enterobacter ; Enterobacter cloacae ; Enterobacteriaceae ; Incidence ; Isoelectric Focusing ; Nalidixic Acid ; Ofloxacin ; Polymerase Chain Reaction ; Prevalence ; Quinolines ; Quinolones ; Restriction Mapping ; Sequence Analysis, DNA

The present study was conducted to identify new target immunogenic molecules from the larval stage of the cattle tick, Boophilus annulatus (Acari: Ixodidae). Two specific larval glycoproteins (GLPs) were isolated by two-step affinity chromatography. The larval immunogens were first purified with CNBr-Sepharose coupled to rabbit anti-larval immunoglobulins, and the glycoproteins were then purified with Con-A Sepharose. These glycoproteins have molecular weights of approximately 32 and 15 kDa with isoelectric points between 6.8 and 7.2. Antibodies against the two GLPs, labeled I and II, were detected in the anti-whole tick, -whole larval, and -gut antigens through immunoblot analysis. These results suggest that these GLPs are good immunogens and can be useful in the vaccination of cattle against tick infestation.
Amino Acid Sequence ; Animals ; Cattle ; Cattle Diseases/immunology/*parasitology/prevention & control ; Chromatography, Affinity ; Electrophoresis, Polyacrylamide Gel ; Glycoproteins/immunology/*isolation & purification ; Immunoblotting ; Isoelectric Focusing ; Ixodidae/chemistry/*immunology ; Male ; Molecular Weight ; Rabbits ; Sequence Analysis, Protein ; Tick Infestations/immunology/parasitology/prevention & control/*veterinary

BACKGROUND: Prevalence of class A extended-spectrum beta-lactamases (ESBLs) has been investigated repeatedly in members of family Enterobacteriaceae in Korea, but only rarely in Acinetobacter baumannii and Pseudomonas aeruginosa. The aims of this study were to determine the prevalence of class A ESBL-producing A. baumannii and P. aeruginosa and to characterize the genotypes. METHODS: During the period of June to September 2004, clinical isolates of A. baumannii and P. aeruginosa were collected from patients in Kosin University Gospel Hospital, Busan, Korea. Antimicrobial susceptibility was determined by the disk diffusion and the agar dilution methods, and ESBLproduction by the double-disk synergy test. Transferability of ceftazidime-resistance of ESBL-producers were tested by conjugation. The isoelectric points of ESBLs were determined by isoelectric focusing. Searches for blaTEM, blaSHV, blaCTX-M, blaPER-1, blaVEB, and blaGES/IBC genes were performed by PCR amplification, and the genotypes of ESBLs were determined by a direct nucleotide sequence analysis of the amplified products. RESULTS: A total of 58 clinical isolates of A. baumannii and 77 P. aeruginosa were collected. Three (5.2%) isolates of A. baumannii and four (5.2%) P. aeruginosa isolates showed positive results in the double-disk synergy test using ceftazidime and imipenem disks, and one (1.7%) A. baumannii and two (2.6%) P. aeruginosa isolates showed positive results in that test using ceftazidime and cefoxitin disks. The most prevalent class A ESBL genotype in A. baumannii isolates was blaPER-1 (n=6), and blaSHV-12 gene was also found in one P. aeruginosa isolate. CONCLUSIONS: It is concluded that class A PER-1 ESBL-producing A. baumannii isolates are spreading, and SHV-12-producing P. aeruginosa has emerged in Korea. The spread of class A ESBLs could compromise the future usefulness of expanded-spectrum -lactam antibiotics for the treatment of A. baumannii and P. aeruginosa infections.
Acinetobacter baumannii* ; Acinetobacter* ; Agar ; Anti-Bacterial Agents ; Base Sequence ; beta-Lactamases* ; Busan ; Cefoxitin ; Ceftazidime ; Diffusion ; Enterobacteriaceae ; Genotype ; Humans ; Imipenem ; Isoelectric Focusing ; Isoelectric Point ; Korea ; Polymerase Chain Reaction ; Prevalence* ; Pseudomonas aeruginosa* ; Pseudomonas*

OBJECTIVE: Comparison of protein expressions by two-dimensional gel electrophoresis (2-DE) in normal cervix and squamous cell carcinoma tissues in Korean women. METHODS: Normal cervix and squamous cell carcinoma tissues were solubilized with 2-DE buffer and the first dimension of PROTEAN IEF CELL, isoelectric focusing (IEF), was performed using pH3-10 linear IPG strips of 17 cm. And then running 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and sliver stain. Scanned image was analyzed using PDQuest 2-D softwareTM. Protein spot spectrum was identified by assisted laser desorption/ionization-time of fighting (MALDI-TOF) and the protein mass spectrum identifications were performed by searching protein databases of Swiss-prot/TrEMBL, Mascot and MS-FIT. RESULTS: We found 9 up-regulation proteins (Alpha enolase, Keratin 19 type I, Keratin 20 type I, Keratin 13 type I, beta-actin, Aflatoxin B1 aldehyde reductase 1, Annexin A2, Squamous cell carcinoma antigen 2, unknown), 7 down-reguation proteins (Annexin 1, Myosin regulatory light chain 2, 14-3-3 protein epsilon, Heat shock 27 kDa protein, Hypothetical protein (DKFZP434C1715), Tumor necrosis factor receptor superfamily member 13B, Smoth muscle protein 22-alpha) and 6 up and down-regulation proteins (Tropomyosin 1, Tropomyosin 2, Tropomyosin 3, Serine (or cysteine) proteinase inhibitor, Phosphatidylinositol transfer protein alpha isoform, Src homology 3 domain-containing protein HIP-55) between normal cervix and squamous cell carcinoma cell tissues. CONCLUSION: 2-DE offers total protein expressions between normal cervix and squamous cell carcinoma cell tissues, and searching of differently expressed protein for the diagnostic markers of squamous cell carcinoma tissue.
14-3-3 Proteins ; Actins ; Aflatoxin B1 ; Aldehyde Reductase ; Annexin A2 ; Carcinoma, Squamous Cell ; Cervix Uteri ; Databases, Protein ; Down-Regulation ; Electrophoresis, Gel, Two-Dimensional* ; Electrophoresis, Polyacrylamide Gel ; Female ; Hot Temperature ; Humans ; Isoelectric Focusing ; Keratin-13 ; Keratin-19 ; Keratin-20 ; Mass Spectrometry* ; Muscle Proteins ; Myosin Light Chains ; Phospholipid Transfer Proteins ; Phosphopyruvate Hydratase ; Receptors, Tumor Necrosis Factor ; Running ; Serine ; Shock ; Sodium Dodecyl Sulfate ; Tropomyosin ; Up-Regulation ; Uterine Cervical Neoplasms*

BACKGROUND: The purposes of this study were to investigate the prevalence of imipenem-resistant clinical Acinetobacter baumannii isolates and to determine the mechanism of the resistance. METHODS: During the period of June to September 2004, susceptibility to imipenem of A. baumannii isolates from a hospital in Busan, Korea were investigated. The isolates were screened for the production of carbapenemase and metallo-beta-lactamase by Modified-Hodge and EDTA-disk synergy tests, respectively; minimum inhibitory concentrations (MICs) were determined by agar dilution method. Genes coding for GES, IMP, VIM, SMP-1, GIM-1 and OXA type beta-lactamases were searched by PCR amplification, and the PCR products were subjected to direct sequencing. Isoelectric points of beta-lactamases were estimated by isoelectric focusing and the epidemiological relationships of isolates were investigated by enterobacterial repetitive intergenic consensus (ERIC) PCR. RESULTS: Fifty eight strains of A. baumannii were isolated from clinical specimens during the surveillance period, and 14 isolates (24.1%) were resistant to imipenem. Of the 14 isolates, 9 were tested positive in Modified-Hodge test and 2 were also positive in EDTA-disk synergy test. Genes encoding OXA-23 and IMP-1 were detected in 7 and 2 isolates, respectively. In IEF studies, OXA-23 and IMP-1 enzymes had corresponding pIs at 6.7 and 9.0, respectively. Seven OXA-23-producing and 2 IMP-1-producing isolates showed the same ERIC PCR patterns. CONCLUSION: It is concluded that 7 and 2 A. baumannii isolates from the patients in a hospital in Busan acquired resistance to imipenem by producing OXA-23 and IMP-1 beta-lactamases, respectively. The isolates producing these beta-lactamases might be originated from a common source.
Acinetobacter baumannii* ; Acinetobacter* ; Agar ; beta-Lactamases ; Busan ; Clinical Coding ; Consensus ; Humans ; Imipenem ; Isoelectric Focusing ; Isoelectric Point ; Korea ; Microbial Sensitivity Tests ; Molecular Epidemiology* ; Polymerase Chain Reaction ; Prevalence

BACKGROUND: Spread of imipenem-resistant Pseudomonas aeruginosa isolates is an important clinical threat. The aim of this study is to survey the prevalence of carbapenem-resistant P.aeruginosa isolates in a university hospital, Busan, Korea, and to determine the mechanisms of the resistance. METHODS: P.aeruginosa isolates from the patients in Kosin University Gospel Hospital were collected during the period of June through September, 2004. Antimicrobial susceptibilities were tested by the disk diffusion method, and production of carbapenemase and metallo-beta-lactamase was determined by the modified Hodge and EDTA-disk synergy tests, respectively. MICs were determined by the agar dilution method, and pIs of beta-lactamases were determined by the isoelectric focusing. Genotypes of carbapenemases were determined by direct sequencing of amplified products. RESULTS: A total of 77 clinical isolates of P.aeruginosa were collected. Twenty-two (55.0%) and 15 (37.5%) isolates showed positive results in the modified Hodge and EDTA-disk synergy tests, re-spectively. Searches for bla OXA-23 and bla IMP-1 genes showed positive results in 15 and 12 isolates, respectively. MIC ranges of imipenem and meropenem to OXA-23-producing isolates were 8-16 microgram/mL and 2-32 microgram/mL, respectively, and those to IMP-1-producing isolates were 2-> or =256 microgram/mL and 2-128 microgram/mL, respectively. CONCLUSION: Production of OXA-23 or IMP-1 is the most prevalent mechanism of imipenem-resistance in P.aeruginosa isolates in a university hospital, Busan, Korea. Periodical surveys are necessary to monitor the spreading of imipenem-resistant isolates and emerging new mechanisms of imipenem-resistance.
Agar ; beta-Lactamases ; Busan ; Diffusion ; Genotype ; Humans ; Imipenem ; Isoelectric Focusing ; Korea ; Prevalence* ; Pseudomonas aeruginosa* ; Pseudomonas*