Screening of Probiotic Bacteria from Intestine and Culture Environment of Hoeven’s slender carp Leptobarbus hoeveni Blkr to Control Pathogenic Bacteria

The ability of probiotic bacteria to control disease infection has been used in aquaculture. This experiment was conducted to isolate and characterize probiotic bacteria; the competition test its ability probiotic bacteria against pathogenic bacteria; and to improve survival rate of Leptobarbus hoeveni. The bacteria were isolated from Leptobarbus hoeveni and its culture environment, and then tested to know its ability to inhibit bacterial fish pathogen in-vitro. Furthermore, the selected probiotic bacteria were tested in vivo to evaluate their ability to inhibit pathogen of Leptobarbus hoeveni. The result showed that probiotic bacteria inhibit the growth of Streptococcus iniae, Flexibacter columnaris, Mycobacterium fortuitum and Aeromonas hydrophila in vitro. Isolate DD3 was the best of candidate probiotic because of the ability to inhibit pathogen, especially A. hydrophila, the most virulent bacteria in Leptobarbus hoeveni. Key Words : probiotic bacteria, Leptobarbus hoeveni, pathogenic bacteria Abstrak Kemampuan bakteri probiotik untuk mengendalikan penyakit infeksi telah digunakan dalam akuakultur. Tujuan penelitian ini adalah mengisolasi dan mengkarakterisasi bakteri probiotik, menguji kemampuan bakteri probiotik terhadap bakteri patogen, sehingga dapat meningkatkan tingkat kelangsungan hidup ikan jelawat. Bakteri diisolasi dari usus ikan jelawat dan lingkungan budaya, kemudian diuji kemampuannya menghambat bakteri patogen secara in-vitro. Selanjutnya bakteri probiotik yang dipilih diuji secara in vivo untuk mengevaluasi kemampuannya dalam menghambat patogen di dalam tubuh ikan jelawat. Dari hasil penelitian diperoleh bakteri probiotik yang diisolasi dari usus dan lingkungan budaya ikan jelawat menunjukkan penghambatan pertumbuhan terhadap Streptococcus iniae, Flexibacter columnaris, Mycobacterium fortuitum dan Aeromonas hydrophila secara in vitro. Isolat DD3 merupakan kandidat probiotik terbaik, karena mempunyai kemampuan untuk menghambat bakteri patogen, khususnya bakteri A. hydrophila adalah bakteri yang paling viluren bagi ikan jelawat. Kata Kunci: bakteri probiotik, ikan jalawat dan baktri patogen

Download Full-text

Application of Bacillus probiotic to prevent Aeromonas hydrophilla infection in Clarias sp.

Jurnal Akuakultur Indonesia ◽

10.19027/jai.13.105-114 ◽

2015 ◽

Vol 13 (2) ◽

pp. 105 ◽

Cited By ~ 3

Author(s):

Mohammad Faizal Ulkhaq ◽

, Widanarni ◽

Angela Mariana Kusumastuti

Keyword(s):

Aeromonas Hydrophila ◽

Pathogenic Bacteria ◽

Clarias Gariepinus ◽

Positive Control ◽

Negative Control ◽

Probiotic Bacteria ◽

African Catfish ◽

Control Application

ABSTRACT The aim of this study was to test the effectiveness of a probiotic Bacillus for the prevention of motile aeromonad septicemia (MAS) disease caused by Aeromonas hydrophila in African catfish (Clarias gariepinus). The study consisted of the inhibition testing of A. hydrophila by Bacillus (in vitro) and the application of probiotic in African catfish (in vivo). The in vivo test, consisted of five treatments such as the addition of probiotic Bacillus P4I1 RifR, Bacillus P4I2 RifR, Bacillus P4I1 RifR + Bacillus P4I2 RifR (Kom), positive control (K+; only added with A. hydrophila) and negative control (K-; without probiotic nor A. hydrophila addition). African catfish (13.35±2.80 g) was maintained in 15 aquariums (40 L in volume) with 30 fishes each for 30 days. Probiotic bacteria was applied in water once a day, whereas pathogenic bacteria A. hydrophila RifR (103 cfu/mL) were added once in earlier treatment (except for the negative control). The result showed that the optimal concentration of Bacillus to inhibit A. hydrophila on in vitro test was 104 cfu/mL. In vivo test showed that the addition of probiotic in media of cultivation could reduce the number of A. hydrophila, improve immune response, and also increase the survival of African catfish compared to positive control. Application of probiotic P4I1 RifR showed the highest survival (92.23%) of all treatments. Keywords: Bacillus, Clarias gariepinus, motile aeromonad septicemia, probiotic ABSTRAK Penelitian ini bertujuan untuk menguji efektivitas probiotik Bacillus dalam pencegahan penyakit motile aeromonad septicaemia (MAS) yang disebabkan oleh Aeromonas hydrophila pada ikan lele dumbo (Clarias gariepinus). Penelitian terdiri atas pengujian penghambatan bakteri probiotik Bacillus terhadap A. hydrophila secara in vitro, dilanjutkan dengan aplikasi pada budidaya ikan lele dumbo (in vivo). Pada uji in vivo, penelitian terdiri atas lima perlakuan yaitu budidaya ikan lele dumbo dengan penambahan probiotik Bacillus P4I1 RifR, Bacillus P4I2 RifR, kombinasi probiotik Bacillus P4I1 RifR + Bacillus P4I2 RifR (Kom), kontrol positif (K+; hanya ditambahkan A. hydrophila) dan kontrol negatif (K-; tanpa pemberian probiotik dan A. hydrophila). Ikan lele dumbo (13,35±2,80 g) dipelihara pada akuarium volume 40 L dengan kepadatan 30 ekor/akuarium selama 30 hari. Bakteri probiotik ditambahkan pada media pemeliharaan ikan setiap hari, sedangkan bakteri patogen A. hydrophila RifR (103 cfu/ mL) diberikan sekali pada awal pemeliharaan (kecuali pada kontrol negatif). Hasil penelitian menunjukkan bahwa konsentrasi terbaik pada penghambatan in vitro adalah dengan penambahan Bacillus 104 cfu/mL. Hasil uji in vivo menunjukkan perlakuan penambahan probiotik pada media budidaya efektif dapat menekan jumlah bakteri A. hydrophila, memperbaiki respons imun, dan meningkatkan kelangsungan hidup ikan lele dumbo dibanding kontrol positif. Perlakuan probiotik P4I1 RifR memberikan hasil terbaik dengan tingkat kelangsungan hidup tertinggi yaitu 92,23%. Kata kunci: Bacillus, Clarias gariepinus, motile aeromonad septicemia, probiotik

Download Full-text

STUDI BACILLUS FIRMUS SEBAGAI KANDIDAT PROBIOTIK DALAM MENGHADAPI Aeromonas hydrophila PADA MEDIA BUDIDAYA The Study of Bacillus firmus as Probiotic Candidate in Supressing Aeromonas hydrophila in Culture Media

SAINTEK PERIKANAN Indonesian Journal of Fisheries Science and Technology ◽

10.14710/ijfst.11.2.111-114 ◽

2016 ◽

Vol 11 (2) ◽

pp. 111

Author(s):

Alfabetian Harjuno Condro Haditomo ◽

Angela Mariana Lusiastuti ◽

Widanarni Widanarni

Keyword(s):

Aeromonas Hydrophila ◽

Pathogenic Bacteria ◽

Culture Media ◽

Inhibition Zone ◽

Probiotic Bacteria ◽

Bacterial Disease ◽

Second Phase ◽

Bacillus Firmus ◽

Culture Methods

ABSTRAK Pengendalian penyakit bakterial yang umum dilakukan dengan pemakaian antibiotik atau bahan kimia sudah tidak diperbolehkan lagi karena menimbulkan patogen yang resisten terhadap bahan kimia tersebut, terlebih jika penggunaan tidak sesuai dengan anjuran yang diberikan. Dampak negatif terhadap kesehatan konsumen berupa residu antibiotik juga menjadi pertimbangan yang harus diperhatikan. Manipulasi terhadap populasi mikroba yang berada di perairan guna pencegahan sebelum terjadinya serangan bakteri yang bersifat mematikan perlu dilakukan sebagaimana konsep probiotik sebagai biokontrol. Tujuan penelitian ini adalah menguji kandidat probiotik dalam menekan atau menghambat bakteri patogen Aeromonas hydrophila. Penelitian ini dilaksananakan dalam dua tahap. Tahap pertama adalah tahap pengujian bakteri kandidat probiotik secara in vitro menggunakan metode zona hambat dan kultur bersama pada media agar. Tahap kedua adalah uji tentang bakteri kandidat probiotik dengan patogen pada media budidaya. Hasil terbaik penelitian tahap pertama pada uji kultur bersama antara kandidat probiotik B. firmus dengan A. hydrophila pada skala in vitro adalah dengan penambahan probiotik B. firmus sebanyak 108 cfu/ml. Sedangkan pada penelitian tahap kedua didapatkan hasil berturut-turut perlakuan D dengan tingkat kelangsungan hidup (SR) mencapai 90%, perlakuan C dengan SR 75%, perlakuan A dengan SR 50% dan perlakuan K dengan SR 50%. Kata kunci: Bacillus firmus, probiotik, Aeromonas hydrophila, media budidaya ABSTRACT Controlling bacterial disease with the use of antibiotics or chemicals is no longer allowed as it results in pathogens that are resistant to the chemicals, especially when not in accordance with the recommendations provided. The negative impactsof the antibiotics residues on the consumers’ health also need to be considered. Manipulation of microbial populations present in the waters as preventation before the lethal attack of bacteria needs to be done which is in accordance with the concept of probiotics as biocontrol.The purpose of this study was to test the probiotic candidates in suppressing or inhibiting pathogenic bacteria Aeromonas hydrophila. This study was conducted in two stages. The first stage was to test a candidate probiotic bacteria in vitro using culture methods and inhibition zone on the media together. The second stage wasto test candidate probiotic bacteria to pathogens on the cultivation media. The best results in the first phase of the research is shared culture test between probiotic candidate B. FIRMUS with A. hydrophila on vitro scale is the addition of the probiotic B. FIRMUS 108 cfu / ml. While in the second phase of the research results obtained successively: treatment D with a survival rate (SR) reaches 90%, treatment C with SR 75%, treatment A with SR 50% and treatment K with SR 50%. Keywords: Bacillus FIRMUS, probiotics, Aeromonas hydrophila, media cultivation

Download Full-text

In vitro antibacterial activities of ethanol extract of iranian propolis (EEIP) against fish pathogenic bacteria (Aeromonas hydrophila, Yersinia ruckeri & Streptococcus iniae)

Brazilian Journal of Microbiology ◽

10.1590/s1517-83822010000400030 ◽

2010 ◽

Vol 41 (4) ◽

pp. 1086-1092 ◽

Cited By ~ 9

Author(s):

Amir Tukmechi ◽

Abdolghaffar Ownagh ◽

Ali Mohebbat

Keyword(s):

Aeromonas Hydrophila ◽

Pathogenic Bacteria ◽

Ethanol Extract ◽

Antibacterial Activities ◽

Streptococcus Iniae ◽

Yersinia Ruckeri

Download Full-text

Selection of lactic acid bacteria as a probiotic and evaluated its performance on gnotobiotic catfish Clarias sp.

Jurnal Akuakultur Indonesia ◽

10.19027/jai.17.1.68-80 ◽

2018 ◽

Vol 17 (1) ◽

pp. 68

Author(s):

Enita Romasni Turnip ◽

Widanarni, Widanarni ◽

Anja Meryandini

Keyword(s):

Growth Rate ◽

Lactic Acid ◽

Survival Rate ◽

Lactic Acid Bacteria ◽

Aeromonas Hydrophila ◽

Pathogenic Bacteria ◽

Challenge Test ◽

Feed Conversion

ABSTRACT This study aimed to select lactic acid bacteria (LAB) as a potential probiotic that producing anti‒microbial compounds in order to treat motile aeromonads septicemia diseases caused by Aeromonas hydrophila on catfish Clarias sp. and evaluated its performance on gnotobiotic catfish. The in vitro assay was done to select several LAB isolates based on antagonistic activity against pathogenic bacteria. The selected isolate was tested in vivo to observe their ability to improve growth performances of catfish. The study was conducted with five treatments consists of K‒ (normal catfish without addition probiotic, without challenge test), K+ (normal catfish without addition of probiotic, with challenge test), Np (normal catfish with addition of probiotic and challenge test), G (gnoto catfish without addition of probiotic, with challenge test), and Gp (gnoto catfish with addition of probiotic and challenge test). The results showed that the addition of Pediococcus pentosaceus E2211 as selected probiotic could increase survival rate, specific growth rate, and immune response towards infection of A. hydrophila. The best survival rate after challenge test was obtained in Np and Gp treatments (88.46%), followed by G treatment (65.38%), while the K+ was only 53.84%. The conclusion of this study was P. pentosaceus E2211 potentially used as a probiotic candidate for normal and gnotobiotic catfish. The presence of normal microflora with P. pentosaceus E2211 in Np treatment showed the best probiotic performance with daily growth rate 3.28%, feed conversion ratio 1.79, and total intestinal bacteria reached 108 CFU/mL significantly different from other treatments (P<0.05).Keywords: Aeromonas hydrophila, catfish, LAB, probiotic, screening ABSTRAKTujuan penelitian ini adalah menyeleksi bakteri asam laktat (BAL) sebagai probiotik potensial penghasil senyawa antimikrob guna menanggulangi penyakit motile aeromonad septicemia akibat Aeromonas hydrophila pada ikan lele Clarias sp. dan evaluasi kinerjanya pada ikan lele gnotobiotik. Pengujian in vitro dilakukan untuk menyeleksi beberapa isolat BAL sebagai kandidat probiotik berdasarkan aktivitas antagonis terhadap bakteri patogen. Isolat terpilih kemudian diuji in vivo untuk mengetahui kemampuannya dalam meningkatkan performa tumbuh ikan lele. Penelitian ini menggunakan rancangan acak lengkap dengan lima perlakuan, yaitu: K‒ (lele normal tanpa probiotik dan tanpa tanpa diuji tantang), K+ (lele normal tanpa probiotik dan diuji tantang), Np (lele normal diberi probiotik dan diuji tantang), G (lele gnoto tanpa probiotik dan diuji tantang), dan Gp (lele gnoto diberi probiotik dan diuji tantang). Hasil penelitian menunjukkan pemberian probiotik terpilih BAL Pediococcus pentosaceus E2211 mampu meningkatkan sintasan, laju pertumbuhan, dan respons imun ikan lele terhadap infeksi A. hydrophila. Sintasan terbaik pascauji tantang diperoleh pada perlakuan Np dan Gp yaitu sebesar 88,46%, diikuti perlakuan G sebesar 65,38%, sementara pada K+ hanya mencapai 53,84%. Kesimpulan dari penelitian ini ialah isolat BAL terpilih P. pentosaceus E2211 berpotensi sebagai kandidat probiotik untuk ikan lele normal dan lele gnotobiotik Clarias sp. Keberadaan mikroflora normal yang berasosiasi dengan P. pentosaceus E2211 pada perlakuan Np menunjukkan kinerja probiotik terbaik dengan nilai laju pertubuhan harian 3,28%, rasio konversi pakan 1,79 dan total bakteri usus mencapai 108 CFU/mL yang berbeda signifikan dibanding perlakuan lainnya (P<0,05).Kata kunci: A. hydrophila, BAL, ikan lele, probiotik, seleksi

Download Full-text

PENAMBAHAN KANDIDAT PROBIOTIK Bacillus methylothrophicus SECARA BERKALA PADA MEDIA PEMELIHARAAN UNTUK PENCEGAHAN INFEKSI BAKTERI Aeromonas hydrophila PADA IKAN NILA (Oreochromis niloticus)

Sains Akuakultur Tropis ◽

10.14710/sat.v3i2.4069 ◽

2019 ◽

Vol 3 (2) ◽

Cited By ~ 1

Author(s):

Femy Musthofa Ardy ◽

Desrina Desrina ◽

Alfabetian Harjuno Condro Haditomo

Keyword(s):

Aeromonas Hydrophila ◽

Oreochromis Niloticus ◽

Pathogenic Bacteria ◽

Survival Rates ◽

Average Weight ◽

In Vitro Test ◽

In Vivo Test ◽

Short Period

Aeromonas hydrophila is a bacteria that causes of MAS disease (motile aeromonad septicemia) in freshwater fish cultivation and can cause mass death in a fairly short period of time in some species including tilapia. There are several alternative strategies in prevention, one of which is the use of probiotic bacteria as agents for controlling or preventing this disease. One candidate for probiotics that has been molecularly identified as 16sRNA and is known to have the ability to inhibit pathogenic bacteria is B. methylotrhrophicus. The aim of this research was to study B.methylotrophicus in inhibiting A. hydrophila in Oreochromis niloticus culture. This research consisted of in vitro and in vivo test that used experiment method with completely randomized design with 4 treatments (density of 1 fishes/l) and 3 replications. The treatment consisted of a mixture of A. hydrophila 102 CFU/mL with B. methylotrophicus 109 CFU/mL (a) without addition of B. methylotrophicus (b) Addition every 3 days, (c) Addition every 5 days, (d) Addition every 7 day. 120 fishes at average weight of 17,5±1,9 g was used as experimental animals. Based on the in vitro test, the most powerful concentration of B. methylotrophicus to inhibit A. hydrophila was 109 cfu/mL with clear zone of 24,9±4,2 mm. In vivo tests show that the addition of B. methylotrophicus periodecally does not significantly affect survival rates, but can slow the gowth of A. hydrophila. Treatment D showed the highest survival rate (13.33%), followed by treatment A (6.66%), B (3.33%), and C (3.33%). These results indicate that B.methylotrophicus can prevent the gowth of A. hydrophila in vitro, and can increase SR by 6.66% in the in vivo test.

Download Full-text

Bacteriophages with Potential to Inactivate Aeromonas hydrophila in Cockles: In Vitro and In Vivo Preliminary Studies

Antibiotics ◽

10.3390/antibiotics10060710 ◽

2021 ◽

Vol 10 (6) ◽

pp. 710

Author(s):

João Duarte ◽

Carla Pereira ◽

Pedro Costa ◽

Adelaide Almeida

Keyword(s):

Aeromonas Hydrophila ◽

Pathogenic Bacteria ◽

Culture Medium ◽

Phage Therapy ◽

Maximum Reduction ◽

Liquid Culture Medium ◽

Resistant Mutants ◽

Bivalve Shellfish

The recurrent emergence of infection outbreaks associated with shellfish consumption is of extreme importance for public health. The present study investigated the potential application of phages AH-1, AH-4, and AH-5 to inactivate Aeromonas hydrophila, a causative agent of infections in humans associated with bivalve shellfish consumption. The inactivation of A. hydrophila was assessed in vitro, using a liquid culture medium, and in vivo, using artificially contaminated cockles with A. hydrophila ATCC 7966. In the in vitro experiments, all phages were effective against A. hydrophila, but phage AH-1 (with a maximum reduction of 7.7 log colonies forming units CFU/mL) was more effective than phages AH-4 and AH-5 (with reductions of 4.9 and 4.5 log CFU/mL, respectively). The cocktails AH-1/AH-4, AH-1/AH-5, AH-4/AH-5, and AH-1/AH-4/AH-5 were slightly more effective than the single phage suspensions. The phages presented a low emergence rate of phage-resistant mutants. When artificially contaminated cockles were treated in static seawater with phage AH-1, around 44% of the added A. hydrophila (1.0 log CFU/g) was inactivated. The results of this study suggest that phage therapy can be an effective alternative to control human pathogenic bacteria during depuration.

Download Full-text

The Effectiveness of Candidate Probiotic Bacteria to Control Vibriosis Disease

Aquatic Science and Technology ◽

10.5296/ast.v5i2.11594 ◽

2017 ◽

Vol 5 (2) ◽

pp. 1

Author(s):

Mulyati Mulyati ◽

Suryati Suryati ◽

Irfani Baga

Keyword(s):

Survival Rate ◽

Sea Water ◽

Challenge Test ◽

Probiotic Bacteria ◽

Pathogenicity Test ◽

Inhibitory Ability ◽

Significant Difference ◽

Portunid Crab

The study aims to isolate, characterize, and examine probiotic bacteria's inhibitory ability against Vibrio harveyi bacteria, both in-vitro and in vivo. Methods used in the study consist of 1) An Isolation of Candidate Probiotic Bacteria, 2) An Antagonistic Test of Candidate Probiotic Bacteria in vitro, 3) An Identification of Bacteria, 4) A Pathogenicity Test of Candidate Probiotic Bacteria, 5) An Antagonistic Test of Candidate Probiotic Bacteria against V. harveyi in vivo. According to the isolation of candidate probiotic bacteria, there are 18 isolated candidate probiotic. After being tested for its inhibitory ability in vitro, there are 8 isolates with zone of inhibition as follows: isolate MM 7 from intestine (22 mm), isolate MM 6 from intestine (12 mm), isolate MM 10 from sea water (10 mm), isolate MM 5 from intestine (9 mm), isolate MM 4 from intestine (8 mm), isolate MM 3 from intestine (7 mm), isolate MM 2.2 from intestine (7 mm), isolate MM 2.1 from intestine (7 mm). Eight genera of the candidate probiotic bacteria is derived from Portunid crab, they are Staphylococcus, Streptococcus, bacillus, vibrio, Alcaligenes, Lactobacillus, micrococcus. Before proceeding the V. harveyi bacterial challenge test in vivo, three potential isolates consisting of MM6, MM7 and MM10 as the probiotic bacteria are pathogenicity-tested against V. harveyi. The survival rate of Portunid crab on pathogenicity test using MM6, MM7 and MM10 generates 91.11-100%, while the control generates 100% survival rate. Variance analysis result through post-hoc Tukey's Honest Significant Difference (HSD) test at 95% confidence interval indicates that isolate MM7 and MM10 are significantly able to increase hatchling Portunid crab's survival rate.

Download Full-text

Extract from phyllosphere bacteria with antibiofilm and quorum quenching activity to control several fish pathogenic bacteria

BMC Research Notes ◽

10.1186/s13104-021-05612-w ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Olivia Nathalia ◽

Diana Elizabeth Waturangi

Keyword(s):

Streptococcus Agalactiae ◽

Aeromonas Hydrophila ◽

Biofilm Formation ◽

Pathogenic Bacteria ◽

Vibrio Harveyi ◽

Quorum Quenching ◽

Indicator Bacteria ◽

Antibiofilm Activity ◽

Fish Pathogen ◽

Phyllosphere Bacteria

Abstract Objective The objective of this research were to screen quorum quenching activity compound from phyllosphere bacteria as well as antibiofilm activity against several fish pathogen bacteria such as Aeromonas hydrophila, Streptococcus agalactiae, and Vibrio harveyi. Results We found eight phyllosphere bacteria isolates with potential quorum quenching activity to inhibit Chromobacterium violaceum as indicator bacteria. Crude extracts (20 mg/mL) showed various antibiofilm activity against fish pathogenic bacteria used in this study. Isolate JB 17B showed the highest activity to inhibit biofilm formation of A. hydrophila and V. harveyi, meanwhile isolate JB 3B showed the highest activity to inhibit biofilm of S. agalactiae. From destruction assay, isolate JB 8F showed the highest activity to disrupt biofilm of A. hydrophila isolate JB 20B showed the highest activity to disrupt biofilm of V. harveyi, isolate JB 17B also showed the highest activity to disrupt biofilm of S. agalactiae.

Download Full-text

Attenuation of Aeromonas hydrophila Infection in Carassius auratus by YtnP, a N-acyl Homoserine Lactonase from Bacillus licheniformis T-1

Antibiotics ◽

10.3390/antibiotics10060631 ◽

2021 ◽

Vol 10 (6) ◽

pp. 631

Author(s):

Mengfan Peng ◽

Wentao Tong ◽

Zhen Zhao ◽

Ling Xiao ◽

Zhaoyue Wang ◽

...

Keyword(s):

Virulence Factors ◽

Bacillus Licheniformis ◽

Aeromonas Hydrophila ◽

Biofilm Formation ◽

Carassius Auratus ◽

Quorum Quenching ◽

Inhibition Rate ◽

Sequence Identity

In this experiment, the quorum quenching gene ytnP of Bacillus licheniformis T-1 was cloned and expressed, and the effect against infection of Aeromonas hydrophila ATCC 7966 was evaluated in vitro and vivo. The BLAST results revealed a 99% sequence identity between the ytnP gene of T-1 and its homolog in B.subtilis sub sp. BSP1, and the dendroGram showed that the similarity in the YtnP protein in T-1 was 100% in comparison with B.subtilis 3610, which was categorized as the Aidc cluster of the MBL family. The AHL lactonase activity of the purified YtnP was detected as 1.097 ± 0.7 U/mL with C6-HSL as the substrate. Otherwise, purified YtnP protein could significantly inhibit the biofilm formation of A.hydrophila ATCC 7966 with an inhibition rate of 68%. The MIC of thiamphenicol and doxycycline hydrochloride against A. hydrophila reduced from 4 μg/mL and 0.5 μg/mL to 1 μg/mL and 0.125 μg/mL, respectively, in the presence of YtnP. In addition, YtnP significantly inhibited the expression of five virulence factors hem, ahyB, ast, ep, aerA of A. hydrophila ATCC 7966 as well (p < 0.05). The results of inhibition on virulence showed a time-dependence tendency, while the strongest anti-virulence effects were within 4–24 h. In vivo, when the YtnP protein was co-injected intraperitoneally with A. hydrophila ATCC 7966, it attenuated the pathogenicity of A. hydrophila and the accumulated mortality was 27 ± 4.14% at 96 h, which was significantly lower than the average mortality of 78 ± 2.57% of the Carassius auratus injected with 108 CFU/mL of A. hydrophila ATCC 7966 only (p < 0.001). In conclusion, the AHL lactonase in B. licheniformis T-1 was proven to be YtnP protein and could be developed into an agent against infection of A. hydrophila in aquaculture.

Download Full-text

Staphylococcus aureus Serves as an Iron Source for Pseudomonas aeruginosa during In Vivo Coculture

Journal of Bacteriology ◽

10.1128/jb.187.2.554-566.2005 ◽

2005 ◽

Vol 187 (2) ◽

pp. 554-566 ◽

Cited By ~ 174

Author(s):

Lauren M. Mashburn ◽

Amy M. Jett ◽

Darrin R. Akins ◽

Marvin Whiteley

Keyword(s):

Staphylococcus Aureus ◽

Pseudomonas Aeruginosa ◽

Pathogenic Bacteria ◽

Iron Acquisition ◽

Low Oxygen ◽

Dialysis Membrane ◽

Opportunistic Human Pathogen ◽

The Impact

ABSTRACT Pseudomonas aeruginosa is a gram-negative opportunistic human pathogen often infecting the lungs of individuals with the heritable disease cystic fibrosis and the peritoneum of individuals undergoing continuous ambulatory peritoneal dialysis. Often these infections are not caused by colonization with P. aeruginosa alone but instead by a consortium of pathogenic bacteria. Little is known about growth and persistence of P. aeruginosa in vivo, and less is known about the impact of coinfecting bacteria on P. aeruginosa pathogenesis and physiology. In this study, a rat dialysis membrane peritoneal model was used to evaluate the in vivo transcriptome of P. aeruginosa in monoculture and in coculture with Staphylococcus aureus. Monoculture results indicate that approximately 5% of all P. aeruginosa genes are differentially regulated during growth in vivo compared to in vitro controls. Included in this analysis are genes important for iron acquisition and growth in low-oxygen environments. The presence of S. aureus caused decreased transcription of P. aeruginosa iron-regulated genes during in vivo coculture, indicating that the presence of S. aureus increases usable iron for P. aeruginosa in this environment. We propose a model where P. aeruginosa lyses S. aureus and uses released iron for growth in low-iron environments.

Download Full-text