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1.
Vibrio harveyi, pathogenic to fish, harbor a hemolysin gene vhh, the homologues of which are found in many species of the Genus Vibrio. In this study, we investigated the prevalence of vhh gene among V. harveyi isolated from Penaeus monodon hatcheries in India by polymerase chain reaction (PCR). The vhh was detected in 67 of the 70 V. harveyi isolates tested in this study using different combinations of PCR primers. A variant vhh gene detected in a minority of strains was cloned, sequenced, and the recombinant protein was expressed in Escherichia coli. The deduced amino acid sequence of the cloned gene was 86% similar to the previously reported amino acid sequences of VHH.
The results of this study suggest that though V. harveyi strains invariably harbor vhh, the sequence variants of the hemolysin gene exist that may impede their detection by PCR. 相似文献
2.
Felipe Lira de Sá Cavalcanti Cristina Rodríguez Mirones Elena Román Paucar Laura álvarez Montes Tereza Cristina Leal-Balbino Marcia Maria Camargo de Morais Luis Martínez-Martínez Alain Antonio Ocampo-Sosa 《Memórias do Instituto Oswaldo Cruz》2015,110(8):1003-1009
An investigation was carried out into the genetic mechanisms responsible for
multidrug resistance in nine carbapenem-resistant Pseudomonas
aeruginosaisolates from different hospitals in Recife, Brazil.
Susceptibility to antimicrobial agents was determined by broth microdilution.
Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding
β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases,
integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC
cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were
separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The
blaSPM-1, blaKPC-2 and blaGES-1
genes were detected in P. aeruginosaisolates in addition to
different AME genes. The loss of OprD in nine isolates was mainly due to frameshift
mutations, premature stop codons and point mutations. An association of loss of OprD
with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates.
Hyper-production of AmpC was also observed in three isolates. Clonal relationship of
the isolates was determined by repetitive element palindromic-PCR and multilocus
sequence typing. Our results show that the loss of OprD along with overexpression of
efflux pumps and β-lactamase production were responsible for the multidrug resistance
in the isolates analysed. 相似文献
3.
Patricia Vollú Silva Raquel Souza Cruz Luiz Sérgio Keim Geraldo Renato de Paula Bernadete Teixeira Ferreira Carvalho Leonardo Rocchetto Coelho Maria Cícera da Silva Carvalho Joel Mauricio Corrêa da Rosa Agnes Marie Sá Figueiredo Lenise Arneiro Teixeira 《Memórias do Instituto Oswaldo Cruz》2013,108(6):812-813
We analysed the antimicrobial susceptibility, biofilm formation and genotypic
profiles of 27 isolates of Staphylococcus haemolyticus obtained
from the blood of 19 patients admitted to a hospital in Rio de Janeiro, Brazil.
Our analysis revealed a clinical significance of 36.8% and a multi-resistance
rate of 92.6% among these isolates. All but one isolate carried the
mecA gene. The staphylococcal cassette chromosome
mec type I was the most prevalent mec
element detected (67%). Nevertheless, the isolates showed clonal diversity based
on pulsed-field gel electrophoresis analysis. The ability to form biofilms was
detected in 66% of the isolates studied. Surprisingly, no icaAD
genes were found among the biofilm-producing isolates. 相似文献
4.
Bacillus cereus, Bacillus thuringiensis and Bacillus anthracis are the major concerns for the food safety in terms of frequency and/or seriousness of the disease. Being members of the
same group and sharing DNA homology to a larger extent, they do create problems when their specific detection/identification
is attempted from different food and environmental sources. Numerous individual polymerase chain reaction (PCR) and few multiplex
PCR (mPCR) methods have been employed to detect these organisms by targeting toxin genes but with lack of internal amplification
control (IAC). Therefore, we attempted a mPCR with IAC for the detection of enterotoxic B. cereus group strains by selecting hbl A, nhe A and cyt K genes from B. cereus, indicative of the diarrheal potential and cry I A and pag genes, the plasmid borne phenotypic markers specific to B. thuringiensis and B. anthracis strains, respectively. Multiplex PCR assay validation was performed by simultaneous comparison with the results of single-target
PCR assays and correlated to the classical conventional and biochemical identification of the organisms. The mPCR was able
to detect as low as 101–102 organisms per ml following overnight enrichment of spiked food samples (vegetable biriyani and milk) in buffered peptone
water (BPW). The presence of these organisms could also be detected by mPCR in naturally contaminated samples of rice based
dishes and milk. The high throughput and cost-effective mPCR method described could provide a powerful tool for simultaneous,
rapid and reliable detection of enterotoxic B. cereus group organisms. 相似文献
5.
S. A. Wani I. Hussain M. A. Rather Z. A. Kabli K. Nagamani Y. Nishikawa S. D. Qureshi I. Khan 《Indian journal of microbiology》2012,52(4):587-592
Fifty-eight typical EAEC isolates from children with diarrhoea were examined for HEp-2 cell adherence assay, presence of dispersin (aap), yersiniabactin (irp2), plasmid encoded toxins (pet), Shigella enterotoxin1 (set1A) and cryptic open reading frame (shf) putative virulence genes by polymerase chain reaction as well as for biofilm production. All the isolates showed aggregative adherence pattern on HEp-2 cells. All but five isolates (91.3 %) carried aap gene. While irp2, pet, set1A and shf genes were detected in 68.9, 5.1, 39.6, and 60.3 % isolates, respectively. Thirty-three (64.7 %) isolates out of 51 tested were found to produce biofilm which was found to be significantly associated only with set1A virulence gene (P = 0.025). Highest amount of biofilm was produced by a strain that possessed all the genes studied. Out of 14 isolates in which the most frequent gene combination (aap, irp2 and shf) was observed, only six produced biofilm. It is concluded that there is significant heterogeneity in putative virulence genes of EAEC isolates from diarrhoeic children and biofilm formation is associated with multiple genes. 相似文献
6.
Nagaveni S Rajeshwari H Oli AK Patil SA Chandrakanth RK 《Indian journal of microbiology》2011,51(1):2-7
Bacterial infections of the central nervous system, especially acute infections such as bacterial meningitis require immediate,
invariably empiric antibiotic therapy due to the widespread emergence of resistance among bacterial species. Nosocomial infections
by Pseudomonas aeruginosa have been described with an increasing trend towards multidrug resistance. P. aeruginosa isolates n = 53 (66%) isolated from the cerebrospinal fluid (CSF) were used for this study. Antibiotic resistance in 53 P. aeruginosa clinical isolates from 80 CSF samples were evaluated. Of these, n = 42 (80%) of the isolates showed multidrug resistance to more than eight antibiotics and n = 17 (32%) isolates were found to be imipenem resistant P. aeruginosa (IMPR-Pa). Genotypical examination by ERIC based PCR revealed minor genetic variations. Polymicrobial infections are common
in the CSF samples. However, high prevalence of P. aeruginosa as an opportunistic pathogen has been developing with increased resistance to antimicrobial agents and thus becoming a significant
threat. 相似文献
7.
8.
Several food borne outbreaks have highlighted the importance of Listeria monocytogenes to the public health and have been recognized as an emerging, important food borne pathogen, and a causative agent of listerioses. A number of genes are involved in the manifestation of Listeria virulence, hlyA is one among them. In the present study, 111 marine fish samples including prawns, finfishes and bivalves were screened for
the presence of Listeria species. The isolates were characterized biochemically and further L. monocytogenes were confirmed by polymerase chain reaction (PCR) technique using the hlyA gene as a tool to differentiate between L. monocytogenes and other non-pathogenic Listeria species. Out of 111 samples 5 (4.5%) samples were positive for L. monocytogenes. Among the three different types of samples bivalves were found to have maximum percent (12.5) of L. monocytogenes followed by prawns (3.84) and finfishes (2.9). Among all the 111 samples, 15 (13.51%) samples were positive for other Listeria species. It was observed that Listeria occurrence is more in shellfishes than in fin fishes. All the isolates were sensitive towards five different antibiotics
in sequence ciprofloxacin > sulphafurazole > norfloxacin > ampicillin and gentamicin. 相似文献
9.
H. Lalzampuia T. K. Dutta Iadarilin Warjri Rajesh Chandra 《Indian journal of microbiology》2013,53(3):291-296
Cephalosporins are major antimicrobials used to treat serious infections. However, their effectiveness is being compromised by the emergence of extended-spectrum β-lactamases (ESBLs). A total of 138 enteric bacteria were isolated from 53 faecal samples of pigs collected from different districts of Mizoram, of which 102 (73.91 %) were Escherichia coli, 26 (18.84 %) were Salmonella spp. and 10 (7.25 %) were Klebsiella pneumoniae. Phenotypic confirmatory test (Double Discs Synergy Test) showed that 8 (5.80 %) E. coli isolates were ESBLs producer. PCR analysis confirmed that out of the eight isolate, 7 (5.07 %) harboured bla CTX-M-1 gene and/or bla TEM gene. Of the eight positive isolates, 7 (5.07 %) and 3 (2.17 %) were found to be positive for bla CTX-M-1 gene and bla TEM gene, respectively, of which 3 (2.17 %) isolates were positive for both the genes. Only 4 (2.90 %) E. coli isolates carried bla CTX-M-1 gene alone. Agarose gel electrophoresis showed that all the isolates were carrying plasmids ranging between 0.9 and ~30 kb. Out of the seven isolates positive for bla CTX-M-1 and/or bla TEM , 2 (1.84 %) isolates were confirmed for bla CTX-M-1 gene in their plasmid. Only one E. coli isolate was found to be positive for both the genes in its plasmid. The resistance plasmid could not be transferred to a recipient by in vitro horizontal gene transfer method. 相似文献
10.
Luiza Pinheiro Carla Ivo Brito Valéria Cataneli Pereira Adilson de Oliveira Carlos Henrique Camargo Maria de Lourdes Ribeiro de Souza da Cunha 《Memórias do Instituto Oswaldo Cruz》2014,109(7):871-878
This study aimed to correlate the presence of ica genes, biofilm
formation and antimicrobial resistance in 107 strains of Staphylococcus
epidermidis isolated from blood cultures. The isolates were analysed to
determine their methicillin resistance, staphylococcal cassette chromosome
mec (SCCmec) type, ica genes
and biofilm formation and the vancomycin minimum inhibitory concentration (MIC) was
measured for isolates and subpopulations growing on vancomycin screen agar. The
mecA gene was detected in 81.3% of the S.
epidermidis isolated and 48.2% carried SCCmec type III.
The complete icaADBC operon was observed in 38.3% of the isolates;
of these, 58.5% produced a biofilm. Furthermore, 47.7% of the isolates grew on
vancomycin screen agar, with an increase in the MIC in 75.9% of the isolates.
Determination of the MIC of subpopulations revealed that 64.7% had an MIC ≥ 4 μg
mL-1, including 15.7% with an MIC of 8 μg mL-1 and 2% with
an MIC of 16 μg mL-1. The presence of the icaADBC operon,
biofilm production and reduced susceptibility to vancomycin were associated with
methicillin resistance. This study reveals a high level of methicillin resistance,
biofilm formation and reduced susceptibility to vancomycin in subpopulations of
S. epidermidis. These findings may explain the selection of
multidrug-resistant isolates in hospital settings and the consequent failure of
antimicrobial treatment. 相似文献
11.
D. Esmenjaud J. C. Minot R. Voisin J. Pinochet M. H. Simard G. Salesses 《Journal of nematology》1997,29(3):370-380
Responses of 17 Prunus rootstocks or accessions (11 from the subgenus Amygdalus and 6 from the subgenus Prunophora) were evaluated against 11 isolates of Meloidogyne spp. including one M. arenaria, four M. incognita, four M. javanica, one M. hispanica, and an unclassified population from Florida. Characterization of plant response to root-knot nematodes was based on a gall index rating. Numbers of females and juveniles plus eggs in the roots were determined for 10 of the rootstocks evaluated against one M. arenaria, one M. incognita, one M. javanica, and the Florida isolate. These 10 rootstocks plus Nemaguard and Nemared were retested by growing three different rootstock genotypes together in containers of soil infested individually with each of the above four isolates. Garfi and Garrigues almonds, GF.305 and Rutgers Red Leaf peaches, and the peach-almond GF.677 were susceptible to all isolates. Differences in resistance were detected among the other rootstocks of the subgenus Amygdalus. The peach-almond GF.557 and Summergrand peach were resistant to M. arenaria and M. incognita but susceptible to M. javanica and the Florida isolate. Nemaguard, Nemared, and its two hybrids G x N no. 15 and G x N no. 22 were resistant to all but the Florida isolate. In the subgenus Prunophora, Myrobalan plums P.1079, P.2175, P.2980, and P.2984; Marianna plum 29C; and P. insititia plum AD.101 were resistant to all isolates. Thus, two different genetic systems of RKN resistance were found in the subgenus Amygdalus: one system acting against M. arenaria and M. incognita, and another system also acting against M. javanica. Prunophora rootstocks bear a complete genetic system for resistance also acting against the Florida isolate. The hypotheses on the relationships between these systems and the corresponding putative genes of resistance are presented. 相似文献
12.
The need for rapid methods in order to precisely detect methicillin-resistant Staphylococcus aureus (MRSA) is extensively
acknowledged. This study evaluated a quantitative real-time PCR assay targeting mecA (encoding high level resistance to
methicillin) and femB (a specific genomic marker for S. aureus) genes to detect MRSA from broth culture, from serum seeded with
MRSA and straight from the patient''s serum. One hundred and thirty-five clinical isolates of MRSA strains and different species
were utilised in this study. In addition, a pilot study with 9 patients'' serum samples was performed. The sensitivity and specificity
values for this assay were 99% and 100% respectively. The detection limit for this method was 1.23×102 CFU/ml from the serum
seeded with MRSA cells and the limiting concentration of DNA for detection was 18 fg, which equates to 5.14 genomic DNA
copies. In addition, this assay detected MRSA from patient''s serum (7 out of 9) with sensitivity of 77.8%. Overall, the assay was
rapid, efficient, sensitive and easy to perform. 相似文献
13.
Kanchana Rungsihirunrat Poonuch Muhamad Wanna Chaijaroenkul Jiraporn Kuesap Kesara Na-Bangchang 《The Korean journal of parasitology》2015,53(1):43-49
The aim of the study was to explore the possible molecular markers of chloroquine resistance in Plasmodium vivax isolates in Thailand. A total of 30 P. vivax isolates were collected from a malaria endemic area along the Thai-Myanmar border in Mae Sot district of Thailand. Dried blood spot samples were collected for analysis of Pvmdr1 and Pvcrt-o polymorphisms. Blood samples (100 μl) were collected by finger-prick for in vitro chloroquine susceptibility testing by schizont maturation inhibition assay. Based on the cut-off IC50 of 100 nM, 19 (63.3%) isolates were classified as chloroquine resistant P. vivax isolates. Seven non-synonymous mutations and 2 synonymous were identified in Pvmdr1 gene. Y976F and F1076L mutations were detected in 7 (23.3%) and 16 isolates (53.3%), respectively. Analysis of Pvcrt-o gene revealed that all isolates were wild-type. Our results suggest that chloroquine resistance gene is now spreading in this area. Monitoring of chloroquine resistant molecular markers provide a useful tool for future control of P. vivax malaria. 相似文献
14.
In this study, an incidence pattern of 1.7% for Yersinia
enterocolitica and 2.5% for Y. intermedia were observed in an analysis of 120 diversified food samples collected from the local market of Mysore, Southern India. Two
native isolates characterized as Y. enterocolitica belonged to biotype 1B and revealed the presence of major virulence related traits such as regulator of virulence, mucoid
Yersinia factor regulator, attachment invasion locus, heat stable enterotoxin, Yersinia type II secretory system and phospholipase A in PCR. Force type neighbor-joining phylograms generated for Y. enterocolitica based on PCR amplicons of rovA and ypl showed 100% homology with two to three strains of Y. enterocolitica and about 75% homology with several strains of Y. pestis. 相似文献
15.
污水厂产超广谱β内酰胺酶大肠杆菌通过接合水平传递耐药性 总被引:1,自引:0,他引:1
【目的】研究废水中产超广谱β-内酰胺酶大肠杆菌中可移动质粒在耐药基因水平传播机制中的作用。【方法】对污水厂分离所得的50株产ESBLs大肠杆菌进行接合试验,并对所得的接合子采用纸片扩散法测定其对15种常见药物的耐药表型,针对质粒介导的产ESBLs菌株的耐药基因设计7对特异性引物对接合子进行PCR扩增。【结果】研究结果显示,80份水样分离得50株产ESBLs大肠杆菌,共接合成功35株细菌,接合成功率高达70%。接合子与供体菌相比,均发生耐药谱型的改变,且存在丢失一种或几种药物耐药性且产生另一种或几种药物耐药性的现象。PCR扩增结果显示,接合子与供体菌相比,耐药基因型有所减少或不变,bla_(TEM)、bla_(CTX-M)基因全部接合成功,bla_(SHV)基因仅1株未接合成功,耐氟喹诺酮类基因未发生转移。【结论】本研究表明,不同的耐药基因可能位于不同的可移动质粒上,可移动质粒在大肠杆菌耐药性水平传播的过程中起到了十分重要的作用。 相似文献
16.
Sandip Madhusudan Swain Chandrasekar Singh Venkatesan Arul 《World journal of microbiology & biotechnology》2009,25(4):697-703
Occurrence of widespread epizootics among larval and cultured shrimp has put on viable preventive approaches such as application
of probiotics on a high priority in aquaculture. In the present study, four probiotics bacteria were isolated from marine
fish and shrimp intestine based on the antagonistic activity and nonpathogenic to the host. The isolates of probiotics strains
Streptococcus phocae PI80, Enterococcus faecium MC13, Lactococcus garvieae LC149, B49 and one commercial probiotics (ECOFORCE) were fed to post larvae of Penaeus monodon obtained from two different hatcheries to analyze the growth and protection against Vibrio harveyi and V. parahaemolyticus. Growth of P. monodon post larvae fed with probiotic strain S. phocae PI80 was significantly (P < 0.001) higher when compared with control and other three strains in both experiments. The treatment of post larvae with
B49 reduced the growth as well as Specific growth rate. Among the three probiotic strains S. phocae PI80 and E. faecium MC13 have effectively inhibited the pathogens. In experiment I high survival (92%) were observed in S. phocae PI80 treated post larvae when challenged with Vibrio harveyi followed by E. faecium MC13 (84%), B49 (76%) and ECOFORCE (68%) but PI80 did not protect the post larvae in the same experiment when they were exposed
to V. parahaemolyticus. The probiotic isolate of MC13 has protected the post larvae against V. parahaemolyticus when compared to other probiotics and control. Similarly in the second experiment feeding of S. phocae enhanced the survival of larvae when challenged with V.
harveyi. The laboratory studies proved that bacterial probionts S. phocae and E. faecium isolated from shrimp and brackishwater fish has potential applications for controlling pathogenic vibriosis in shrimp culture. 相似文献
17.
Monika Eliza ?ysakowska Andrzej Denys Monika Sienkiewicz 《Indian journal of microbiology》2012,52(4):612-616
Surface proteins play an important role in the pathogenesis of enterococcal infections. Some of them are candidates for a vaccine, e.g., the frequency of endocarditis in rats vaccinated with Ace protein was 75 % as 12 opposed to 100 % in those who weren’t. However, there are other components of enterococcal cells, such as Epa antigens or internalin-like proteins, which may be used in the prophylaxis of infections caused by them. However, also other virulence factors and resistance to antibiotics are important during enterococcal infection. Therefore, the relevance of ace, epa, elrA, other virulence genes, as well as resistance to antibiotics was investigated. 161 Enterococcus faecalis strains isolated from teaching hospitals in Lodz, cultured according to standard microbiological methods, were investigated for the presence of genes encoding surface proteins by PCR. Results were analyzed with χ2 test. The elrA gene was found in all clinical and environmental strains, the ace gene was also widespread among E. faecalis (96.9 %). Both tested epa genes were found in the majority of isolates (83.25 %). There was correlation between the presence of esp and ace genes (p = 0.046) as well as between epa and agg genes (p = 0.0094; χ2 test). The presence of the genes encoding surface proteins investigated in our study in the great majority of isolates implies that they would appear to be required during E. faecalis infection. Therefore, they could be excellent targets in therapy of enterococcal infections or, as some studies show, candidates for vaccines. 相似文献
18.
Ozdemir GB Oryaşın E Bıyık HH Ozteber M Bozdoğan B 《Indian journal of microbiology》2011,51(2):182-187
A collection of 57 enterococcal isolates from different origin (including river, treatment plant, spring and garbage water,
soil, animal, and vegetables from Aydın) was screened for the production of bacteriocins. Enterococci were identified at
species levels as Enterococcus faecium (34), E. hirae (6), E. casseliflavus (4), E. durans (4), E. faecalis (4), E. mundtii (3) and E. avium (2). Of the 57 isolates 40 of them inhibited the growth of at least one indicator bacterium. Based on our PCR results 54
strains possesed enterocin genes. The genes of entA and entB were the most frequently detected structural genes among the PCR positive strains (54 and 53 strains, respectively) and the
entB gene was always associated with entA gene. The highest combination of enterocin genes (24 of 54 strains) detected was entA, entB, entP and entL50A/B. The enterocins AS-48 and CylLLS genes were not found. Three enterococcal isolates, 2 E. faecium and 1 E. hirae were not harbour any of tested enterocin genes. No correlation between the presence of enterocin structural genes and the
origin of the strain was detected, also no relationship seemed to exist between the tested enterocin genes and the activity
spectra of isolates. Genes encoding bacteriocins are widely disseminated among enterocci from different origin and more studies
should be done for evaluate industrial potential of bacteriocins. 相似文献
19.
20.
Guillermo D Repizo Martín Espariz Víctor S Blancato Cristian A Suárez Luis Esteban Christian Magni 《BMC genomics》2014,15(1)