BACKGROUND AND OBJECTIVE: Many opportunistic and nosocomial pathogens like Pseudomonas aeruginosa are very reliant on a bacterium-to-bacterium communication system called quorum sensing (QS). Without the aforementioned process, gene expressions associated with virulence factors will not be produced. In this study, the sub-inhibitory concentrations (sub-MICs) of methanolic leaf extract and obtained fractions from Averrhoa bilimbi (kamias) were screened for ability to inhibit quorum sensing-controlled phenotypes of P. aeruginosa ATCC 27853. METHODOLOGY: A. bilimbi crude extract was fractionated through liquid-liquid extraction, producing four (4) fractions: hexane fraction, dichloromethane (DCM) fraction, ethyl acetate (EtOAc) fraction, and water (H2O) fraction. Among the sub-MICs obtained from resazurin-based fluorimetric microtiter assay, only 50 μg/mL was utilized in evaluating the anti-QS properties of crude extract and fr RESULTS: In the swarming motility assay, hexane fraction (9.39 mm ± 0.67) and DCM fraction (10.82 mm ± 0.95) displayed restriction in the treated P. aeruginosa ATCC 27853 swarms against the control (16.20 mm ± 2.55). In the anti-pyocyanin production assay, hexane fraction exhibited an inhibition of 42.66 % ± 12.94. TLC analysis and phytochemical screening revealed that hexane fraction contains steroids, terpenes, triterpenes, and glycolipids; and DCM fraction contains cardiac glycosides, triterpenoids, terpenes, triterpenes, steroids, alkaloids, and glycolipids. CONCLUSION Hexane and DCM fractions obtained from A. bilimbi significantly inhibited swarming of P. aeruginosa ATCC 27853 while none of the extracts were able to significantly inhibit pyocyanin formation of P. aeruginosa ATCC 27853.
Pseudomonas aeruginosa ; Averrhoa bilimbi ; quorum sensing ; pyocyanin

BACKGROUND: The accurate and rapid identification (ID) of nonfermentative gram-negative bacilli (NFB) is essential for diagnostic and therapeutic purposes and for epidemiologic studies of hospital infections. Commercial identification systems of NFB are easy to use but too expensive. The aim of the study was to develop a simple system for the identification of NFB species which are frequently isolated from clinical specimens. METHODS: Eighteen biochemical tests used in NFB microplate ID system were pyocyanin in Tech media; pyoverdin in Flo media; glucose fermentation, acid formation from glucose, maltose, lactose, sucrose, and mannitol in oxidation-fermentation media; Nitrate and nitrite reduction in nitrate media; fornithine decarboxylase, lysine decarboxylase, and arginine dihydrolase in Moeller decarboxylase media; acetamide, urease, citrate, 42degrees C growth, and oxidase test. For the establishment of NFB's biochemical data in microplate ID system, 175 consecutive isolates of NFB from clinical specimens isolated during the period of April 2000 were simultaneously tested by microplate method and API 32GN. RESULTS: Ninety-two percent of clinical isolates of NFB were identified to the species level by NFB microplate ID system. CONCLUSIONS: The NFB microplate ID system is simple to use, rapid and economical. Further modification are needed to improve the accuracy and identification rate of NFB isolates.
Arginine ; Citric Acid ; Cross Infection ; Fermentation ; Glucose ; Lactose ; Lysine ; Maltose ; Mannitol ; Oxidoreductases ; Pyocyanine ; Sucrose ; Urease

Infections with Pseudomonas aeruginosa are difficult to treat not only because it is often associated with multidrug-resistant infections but also it is able to form biofilm. The aim of this study was to evaluate the antibiofilm and anti-Quorum Sensing (QS) activities of Thymbra capitata essential oils (EOs) against Beta Lactamase (BL) producing P. aeruginosa and the reference strain P. aeruginosa 10145. GC/MS analysis showed that thymol (23.25%) is the most dominant compound in T. capitata EOs. The MICs of T. capitata EOs against P. aeruginosa (BL) and P. aeruginosa 10145 were 1.11%. At sub MIC (0.041, 0.014 and 0.0046%), the EOs of T. capitata remarkably inhibited the biofilm formation of both strains tested and complete inhibition of the biofilm formation was reported at 0.041%. The EOs of T. capitata were found to inhibit the swarming motility, aggregation ability and hydrophobic ability of P. aeruginosa (BL) and P. aeruginosa 10145. Interestingly, the EOs of T. capitata reduce the production of three secreted virulence factors that regulated by QS system including pyocyanin, rhamnolipids and LasA protease. The potent antibiofilm and anti-QS activities of T. capitata EOs can propose it as a new antibacterial agent to control pseudomonas infections.
beta-Lactamases ; Biofilms ; Oils, Volatile ; Pseudomonas aeruginosa ; Pseudomonas Infections ; Pseudomonas ; Pyocyanine ; Quorum Sensing ; Thymol ; Virulence Factors ; Virulence

49 strains of Pseudomonas aeruginosa were isolated from chronic wounds associated with orthopedic surgical field at Taegu armed forces general hospital. In the present report, authors have studied the Pyocin type of isolated strains by Gillies and Govans method. Also observed various interrelationship in associaton with Pyocin type, Pyocyanine formation, Oxidase reaction and antibiotic sensitivity. The results were obtained as follows; 1) Among the 49 strains tested in term of pyocin type, 41 strains(81.6%) were found to be typable and 8 strains (16.4%) to be untypable. Among the pyocin type of 41 typables, unclassified type was the most prominent type 17 strains (41.5%) and followed by type I(11 strains), 10 (3 strains), 5 (2 strains) and other type. 2) In the relationship among pyocyanine formation, oxidase reaction and pyocin type, no definite conclusion can be reached due to the paucity of tested strains except that more strains belong to the pyocin type I of the Pyocyanine negative strains. 3) In antibiotic sensitivity of isolated strains tested by plate dilution method, most of all strains were resistant to Kanamycin and Neomycin but few strains were moderate sensitive to Colistin, Polymyxin B, and Terramycin. 4) The Pyocin type of isolated strains were not related with antibiotic sensitivity to Colistin, Polymyxin B and Terramycin substantially.
Arm ; Colistin ; Daegu ; Hospitals, General ; Kanamycin ; Methods ; Neomycin ; Orthopedics ; Oxidoreductases ; Oxytetracycline ; Polymyxin B ; Pseudomonas aeruginosa ; Pseudomonas ; Pyocins ; Pyocyanine ; Wounds and Injuries

OBJECTIVETo investigate the effect of andrographolide on virulence factors production in Pseudomonas aeruginosa.

METHODGrowth rate, pyocyanin, proteolytic activity and elastase activity were measured with or without the presence of andrographolide. The effect of andrographolide on pyocyanin production, proteolytic activity and elastase activity in PAO-JP2 was investigated simultaneously.

RESULTThe andrographolide did not affect the growth of PAO1 in planktonic culture. The production of pyocyanin, proteolytic activity and elastase activity were significanthy suppressed in P. aeruginosa cultures grown in the presence of andrographolide. However, these effects were not observed in PAO-JP2.

CONCLUSIONThe inhibiting effect of andrographolide on virulence factors production in P. aeruginosa may play a role in its anti-infection activity.

Andrographis ; chemistry ; Anti-Bacterial Agents ; pharmacology ; Diterpenes ; isolation & purification ; pharmacology ; Pancreatic Elastase ; metabolism ; Peptide Hydrolases ; metabolism ; Plants, Medicinal ; chemistry ; Pseudomonas aeruginosa ; growth & development ; metabolism ; pathogenicity ; Pyocyanine ; metabolism ; Virulence Factors ; metabolism