Aeromonas hydrophila infection has been increasingly found, in particular among patients with various underlying diseases. Many characteristics of this organism are quite similar to those of Enterobacteriaceae and Vibrio, making an accurate identification difficult. In a period of 2 years, the authors obtained a total of 27 isolates of A. hydrophila from clinical materials, and their cultural and biochemical characteristics are herewith reported. Some of the most important clues to suspect this organism were a wide zone of complete hemolysis on blood agar, partially alkaline slant, acid butt, and small amount of gas in trip1e sugar iron agar (TSI), weak indole reaction, and negative ornithine decarboxylase in motility indole ornithine medium (MIO), and usually positive citrate utilization. It is concluded that the identification of this organism should be possible on the basis of deoxyribonuclease (DNase), oxidase, and a few other tests. Our isolates showed a similar antibiotic susceptibility to those reported in other countries; i.e., a11 were resistant to ampicillin and most were susceptible to other antibiotics, excluding cephalothin.
Aeromonas/drug effects ; Aeromonas/isolation & purification* ; Aeromonas/physiology ; Antibiotics/pharmacology ; Culture Media ; Human ; Microbial Sensitivity Tests

Chondroitinase has been used as an important tool in the study of the structure, function and distribution of glycosaminoglycans for many years. Recently, the enzyme has been reported to be a potential enzyme for chemonucleolysis, an established treatment for intervertebral disc protrasion. In this paper, a chondroitinase had been purified from the culture supernatant of Aeromonas sobria YH311 using a simple purification procedure of ammonium sulfate precipitation, QAE-Sephadex A50 ion exchange chromatography and Sephadex G-150 gel filtration. The immobilization of purified chondroitinase using sodium alginate or cellulose as carriers has also been studied. The chondroitinase obtained from Aeromonas sobria YH311 was purified 55-fold to 95.3% pure, the specific activity of the purified enzyme was 31.86u/mg and the yield was 37%. The molecular weight of chondroitinase from Aeromonas sobria YH311 was determined by SDS-PAGE to be 80kD, which was almost the same as those chondroitinase AC from Arthrobacter aurescens, Aeromonas liquefaciens and Flavobacterium heparinum. But its isoelectric point was 4.3 - 4.6, which was far lower than the microbial chondroitinase AC. After the immobilization on sodium alginate or cellulose, the properties of chondroitinase changed greatly. The optimum temperature and pH of the free enzyme were 50 degrees C and 7.0 respectively, and about 10% activity remained after heat treatment at 80 degrees C for 20 minutes, and 47% activity remained after two weeks storage at 4 degrees C. The chondroitinase immobilized on sodium alginate had the optimum temperature and pH of 40 degrees C and 7.0 respectively, about 50% activity remained after 80 degrees C heat treatment for 120 minutes and 50% remained after 30 days storage at 4 degrees C. The chondroitinase immobilized on cellulose had the optimum temperature and pH of 70 degrees C and 6.0 respectively, and more than 70% activity remained after heat treatment at 80 degrees C and 30 days storage at 4 degrees C. The yield of the immobilization was very low, with 18.56% for alginate and 18.86% for cellulose.
Aeromonas ; enzymology ; Chondroitinases and Chondroitin Lyases ; isolation & purification ; metabolism ; Enzyme Stability ; Enzymes, Immobilized ; metabolism ; Temperature

No abstract available.
Aeromonas/isolation & purification ; *Drug Resistance, Bacterial ; Gram-Negative Bacteria/drug effects/isolation & purification ; Humans ; Korea ; Methicillin Resistance ; Peritonitis/drug therapy/*microbiology

PURPOSE: The genus Aeromonas is a pathogen that is well known to cause severe clinical illnesses, ranging from gastroenteritis to sepsis. Accurate identification of A. hydrophila, A. caviae, and A. veronii is important for the care of patients. However, species identification remains difficult using conventional methods. The aim of this study was to compare the accuracy of different methods of identifying Aeromonas at the species level: a biochemical method, matrix-assisted laser desorption ionization mass spectrometry-time of flight (MALDI-TOF MS), 16S rRNA sequencing, and housekeeping gene sequencing (gyrB, rpoB). MATERIALS AND METHODS: We analyzed 65 Aeromonas isolates recovered from patients at a university hospital in Korea between 1996 and 2012. The isolates were recovered from frozen states and tested using the following four methods: a conventional biochemical method, 16S rRNA sequencing, housekeeping gene sequencing with phylogenetic analysis, and MALDI-TOF MS. RESULTS: The conventional biochemical method and 16S rRNA sequencing identified Aeromonas at the genus level very accurately, although species level identification was unsatisfactory. MALDI-TOF MS system correctly identified 60 (92.3%) isolates at the species level and an additional four (6.2%) at the genus level. Overall, housekeeping gene sequencing with phylogenetic analysis was found to be the most accurate in identifying Aeromonas at the species level. CONCLUSION: The most accurate method of identification of Aeromonas to species level is by housekeeping gene sequencing, although high cost and technical difficulty hinder its usage in clinical settings. An easy-to-use identification method is needed for clinical laboratories, for which MALDI-TOF MS could be a strong candidate.
Aeromonas/classification/*genetics/isolation & purification ; DNA, Bacterial/genetics ; Genes, Essential/*genetics ; Humans ; Molecular Typing/*methods ; Phylogeny ; RNA, Ribosomal, 16S/*genetics ; Republic of Korea ; Sensitivity and Specificity ; Sequence Analysis, DNA/*methods ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/*methods

OBJECTIVETo study the status of beta-lactamase produced by multiresistant Aeromonas selected from cirrhosis patients to provide reference for treatment and reduce resistance and control spreading.

METHODSFour multiresistant Aeromonas strains isolated from serious liver cirrhosis patients from the No. 302 hospital. The TEM resistant genes were detected by PCR and agarose gel electrophoresis.

RESULTSThree TEM-1 positive strains were detected from four multiresistant Aeromonas isolates consisting of one Aeromonas sobria and three Aeromonas hydrophila isolated from blood and ascites. This was further confirmed by gene sequencing. The multiresistance to antibiotics was higher in four Aeromonas isolates. All strains tested were resistant to ampicillin, cefazolin and cefmetazole.The cirrhosis patients who suffered from Aeromonas infection had poor prognosis and had mortality rate of 3/4.

CONCLUSIONThe beta-lactamase TEM-1 resistant genes was detected in clinical multiresistant Aeromonas strain isolated from serious cirrhosis patients.The results suggested that TEM-1 was the main resistance mechanism of Aeromonas strain and was reduced by adding enzyme inhibitor.

Adult ; Aeromonas ; drug effects ; genetics ; isolation & purification ; Anti-Bacterial Agents ; pharmacology ; Drug Resistance, Bacterial ; genetics ; Gram-Negative Bacterial Infections ; microbiology ; Humans ; Liver Cirrhosis ; microbiology ; Male ; Middle Aged ; Prognosis ; beta-Lactamases ; genetics

Objective: This study aimed to evaluate the genetic diversity, virulence, and antimicrobial resistance of isolates from clinical patients, tap water systems, and food. Methods: Ninety isolates were obtained from Ma'anshan, Anhui province, China, and subjected to multi-locus sequence typing (MLST) with six housekeeping genes. Their taxonomy was investigated using concatenated sequences, while their resistance to 12 antibiotics was evaluated. Ten putative virulence factors and several resistance genes were identified by PCR and sequencing. Results: The 90 isolates were divided into 84 sequence types, 80 of which were novel, indicating high genetic diversity. The isolates were classified into eight different species. PCR assays identified virulence genes in the isolates, with the enterotoxin and hemolysin genes , , , and found in 47 (52.2%), 13 (14.4%), 22 (24.4%), and 12 (13.3%) of the isolates, respectively. The majority of the isolates (≥ 90%) were susceptible to aztreonam, imipenem, cefepime, chloramphenicol, gentamicin, tetracycline, and ciprofloxacin. However, several resistance genes were detected in the isolates, as well as a new variant. Conclusions Sequence type, virulence properties, and antibiotic resistance vary in isolates from clinical patients, tap water systems, and food.
Aeromonas ; drug effects ; genetics ; isolation & purification ; pathogenicity ; Anti-Bacterial Agents ; pharmacology ; China ; Drinking Water ; microbiology ; Drug Resistance, Bacterial ; Food Microbiology ; Genetic Variation ; Gram-Negative Bacterial Infections ; microbiology ; Species Specificity ; Virulence