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1.
Young-hee Jin Young-hee Oh Ji-hun Jung Soo-jin Kim Jin-ah Kim Ki-young Han Min-young Kim Seog-gee Park Young-ki Lee 《Journal of microbiology (Seoul, Korea)》2010,48(2):236-242
A total of 66 Shigella sonnei isolates from 1999 to 2008 in Seoul was analyzed for their antimicrobial resistance, carriage of integron, and the patterns
of Pulsed-field gel electrophoresis (PFGE). A high level of antimicrobial resistance to streptomycin (100%), trimethoprim/sulfamethoxazole
(95%), tetracycline (94%), nalidixic acid (65%), and ampicillin (41%) was observed among S. sonnei isolates. Fourteen profiles of antimicrobial resistance were identified with the most common resistance profile being nalidixic
acid, streptomycin, tetracycline, and trimethoprim/sulfamethoxazole (35%). PCR and DNA sequencing analysis revealed the presence
of class 2 integron in all isolates, and class 1 and 2 integrons in 7 isolates. The class 2 integron carried two types of
gene cassettes. One cassette array was dfrI, sat2, and aadA1 (91%), and the other was dfr1 and sat1 (8%). dfrA12 and aadA2 gene cassette was found in one isolate containing class 1 integron. PFGE was carried out to examine the genetic relatedness
among isolates. All isolates except for one showed similar PFGE patterns (similarity of 80.1%). These results suggest that
the S. sonnei isolated during 1999–2008 in Seoul have similar lineages that have not undergone evolutionary changes with time. 相似文献
2.
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
3.
Hitoki Yamanaka Toshikazu Takagi Makiko Ohsawa Naoto Yamamoto Noriaki Kubo Takahira Takemoto Shoko Sasano Ritsuko Masuyama Kazutaka Ohsawa 《Experimental Animals》2014,63(3):297-304
To determine the prevalence of drug resistant bacteria colonizing laboratory mice, we
isolated and characterized vancomycin-resistant Enterococcus species
(VRE) from commercially available mice. A total of 24 VRE isolates were obtained from 19
of 21 mouse strains supplied by 4 commercial breeding companies. Of these, 19 isolates of
E. gallinarum and 5 isolates of E. casseliflavus
possessing the vanC1 and vanC2/3 genes intrinsically,
exhibited intermediate resistance to vancomycin respectively. In addition, these isolates
also exhibited diverse resistant patterns to erythromycin, tetracycline, and
ciprofloxacin, whereas the use of antibiotics had not been undertaken in mouse strains
tested in this study. Although 6 virulence-associated genes (ace,
asa, cylA, efaA,
esp, and gelE) and secretion of gelatinase and hemolysin
were not detected in all isolates, 23 of 24 isolates including the isolates of E.
casselifalvus secreted ATP into culture supernatants. Since secretion of ATP by
bacteria resident in the intestinal tract modulates the local immune responses, the
prevalence of ATP-secreting VRE in mice therefore needs to be considered in animal
experiments that alter the gut microflora by use of antibiotics. 相似文献
4.
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
5.
Fernando José Vicenzi Marcelo Pillonetto Helena Aguilar Peres Homem de Mello de Souza Jussara Kasuko Palmeiro Carlos Ant?nio Riedi Nelson Augusto Rosario-Filho Libera Maria Dalla-Costa 《Memórias do Instituto Oswaldo Cruz》2016,111(1):37-42
Cystic fibrosis (CF) patients with Burkholderia cepacia complex
(Bcc) pulmonary infections have high morbidity and mortality. The aim of this study
was to compare different methods for identification of Bcc species isolated from
paediatric CF patients. Oropharyngeal swabs from children with CF were used to obtain
isolates of Bcc samples to evaluate six different tests for strain identification.
Conventional (CPT) and automatised (APT) phenotypic tests, polymerase chain reaction
(PCR)-recA, restriction fragment length
polymorphism-recA, recAsequencing, and
matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) were applied.
Bacterial isolates were also tested for antimicrobial susceptibility.
PCR-recA analysis showed that 36 out of the 54 isolates were Bcc.
Kappa index data indicated almost perfect agreement between CPT and APT, CPT and
PCR-recA, and APT and PCR-recA to identify Bcc,
and MALDI-TOF and recAsequencing to identify Bcc species. The
recAsequencing data and the MALDI-TOF data agreed in 97.2% of the
isolates. Based on recA sequencing, the most common species
identified were Burkholderia cenocepacia IIIA
(33.4%),Burkholderia vietnamiensis (30.6%), B.
cenocepaciaIIIB (27.8%), Burkholderia multivorans
(5.5%), and B. cepacia (2.7%). MALDI-TOF proved to be a useful tool
for identification of Bcc species obtained from CF patients, although it was not able
to identify B. cenocepacia subtypes. 相似文献
6.
Anna Zawistowska-Rojek Agnieszka Kociszewska Tomasz Zarba Stefan Tyski 《Polish journal of microbiology》2022,71(3):395
Lactic acid bacteria are used in various types of probiotic products. Due to the constantly growing probiotics market, new strains with pro-health properties are sought. The present study compared 39 strains of Lactobacillus, Lacticaseibacillus, and Lactiplantibacillus, isolated from probiotic products and healthy people. The current research aimed to search for new, potentially probiotic strains. For this purpose the relationship between Lactobacillaceae strains was carried out; moreover, the basic properties of probiotic microorganisms, such as survival at low pH and bile salt environment, antibiotic susceptibility, aggregation and antagonism were estimated. The properties of these isolates were also compared with the properties of probiotic strains from the ATCC collection. In comparing the genetic relationship (PFGE method) between the tested isolates, it was observed that some of them show a high degree of similarity. All tested strains tolerated an environment with a pH value of 3.0, and the addition of 0.3% bile salt; showed auto-aggregation properties and displayed antagonism against pathogenic microorganisms. In the present study, the bacteria were susceptible to tetracycline, chloramphenicol and ampicillin; the resistance to vancomycindepended on the bacteria type. All the properties were strain-depended. Most of the tested strains had properties comparable to the reference strains. Three L. acidophilus strains isolated from cervical swabs seem to be promising candidates for probiotic strains. Key words: lactobacilli, PFGE, antimicrobial susceptibility, antagonism 相似文献
7.
Jae-Young Oh Yong-Kuk Kwon Bai Wei Hyung-Kwan Jang Suk-Kyung Lim Cheon-Hyeon Kim Suk-Chan Jung Min-Su Kang 《Journal of microbiology (Seoul, Korea)》2017,55(1):13-20
Thirty-nine human isolates of Campylobacter jejuni obtained from a national university hospital during 2007–2010 and 38 chicken isolates of C. jejuni were collected from poultry farms during 2009–2010 in South Korea were used in this study. Campylobacter genomic species and virulence-associated genes were identified by PCR. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were performed to compare their genetic relationships. All isolates were highly resistant to ciprofloxacin, nalidixic acid, and tetracycline. Of all isolates tested, over 94% contained seven virulence associated genes (flaA, cadF, racR, dnaJ, cdtA, cdtB, and cdtC). All isolates were classified into 39 types by PFGE clustering with 90% similarity. Some chicken isolates were incorporated into some PFGE types of human isolates. MLST analysis for the 39 human isolates and 38 chicken isolates resulted in 14 and 23 sequence types (STs), respectively, of which 10 STs were new. STs overlapped in both chicken and human isolates included ST-21, ST-48, ST-50, ST-51, and ST-354, of which ST-21 was the predominant ST in both human and chicken isolates. Through combined analysis of PFGE types and STs, three chicken isolates were clonally related to the three human isolates associated with food poisoning (VII-ST-48, XXII-ST-354, and XXVIII-ST-51). They were derived from geographically same or distinct districts. Remarkably, clonal spread of food poisoning pathogens between animals and humans was confirmed by population genetic analysis. Consequently, contamination of campylobacters with quinolone resistance and potential virulence genes in poultry production and consumption may increase the risk of infections in humans. 相似文献
8.
Carolina Baldisserotto Comerlato Mariah Costa Carvalho de Resende Juliana Caier?o Pedro Alves d'Azevedo 《Memórias do Instituto Oswaldo Cruz》2013,108(5):590-595
Despite the increasing importance of Enterococcus as
opportunistic pathogens, their virulence factors are still poorly understood.
This study determines the frequency of virulence factors in clinical and
commensal Enterococcus isolates from inpatients in Porto
Alegre, Brazil. Fifty Enterococcus isolates were analysed and
the presence of the gelE, asa1 and
esp genes was determined. Gelatinase activity and biofilm
formation were also tested. The clonal relationships among the isolates were
evaluated using pulsed-field gel electrophoresis. The asa1,
gelE and esp genes were identified in 38%,
60% and 76% of all isolates, respectively. The first two genes were more
prevalent in Enterococcus faecalis than in Enterococcus
faecium, as was biofilm formation, which was associated with
gelE and asa1 genes, but not with the
esp gene. The presence of gelE and the
activity of gelatinase were not fully concordant. No relationship was observed
among any virulence factors and specific subclones of E.
faecalis or E. faecium resistant to vancomycin. In
conclusion, E. faecalis and E. faecium
isolates showed significantly different patterns of virulence determinants.
Neither the source of isolation nor the clonal relationship or vancomycin
resistance influenced their distribution. 相似文献
9.
Carol H. Sandt Paula J. Fedorka-Cray Deepanker Tewari Stephen Ostroff Kevin Joyce Nkuchia M. M’ikanatha 《PloS one》2013,8(10)
Salmonellosis is one of the most important foodborne diseases affecting humans. To characterize the relationship between Salmonella causing human infections and their food animal reservoirs, we compared pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility patterns of non-typhoidal Salmonella isolated from ill humans in Pennsylvania and from food animals before retail. Human clinical isolates were received from 2005 through 2011 during routine public health operations in Pennsylvania. Isolates from cattle, chickens, swine and turkeys were recovered during the same period from federally inspected slaughter and processing facilities in the northeastern United States. We found that subtyping Salmonella isolates by PFGE revealed differences in antimicrobial susceptibility patterns and, for human Salmonella, differences in sources and invasiveness that were not evident from serotyping alone. Sixteen of the 20 most common human Salmonella PFGE patterns were identified in Salmonella recovered from food animals. The most common human Salmonella PFGE pattern, Enteritidis pattern JEGX01.0004 (JEGX01.0003ARS), was associated with more cases of invasive salmonellosis than all other patterns. In food animals, this pattern was almost exclusively (99%) found in Salmonella recovered from chickens and was present in poultry meat in every year of the study. Enteritidis pattern JEGX01.0004 (JEGX01.0003ARS) was associated with susceptibility to all antimicrobial agents tested in 94.7% of human and 97.2% of food animal Salmonella isolates. In contrast, multidrug resistance (resistance to three or more classes of antimicrobial agents) was observed in five PFGE patterns. Typhimurium patterns JPXX01.0003 (JPXX01.0003 ARS) and JPXX01.0018 (JPXX01.0002 ARS), considered together, were associated with resistance to five or more classes of antimicrobial agents: ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracycline (ACSSuT), in 92% of human and 80% of food animal Salmonella isolates. The information from our study can assist in source attribution, outbreak investigations, and tailoring of interventions to maximize their impact on prevention. 相似文献
10.
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
11.
The marine-estuarine bacterium Vibrio harveyi is an important pathogen of invertebrates, most significantly, the larvae of commercially important shrimp Penaeus monodon. In this study, we analyzed V. harveyi isolated from shrimp hatchery environments for understanding the distribution of putative virulence genes and antimicrobial
drug resistance. The putative genes targeted for PCR detection included four reversible toxin (Rtx)/hemolysin genes, a gene
encoding homologue of Vibrio
cholerae zonula occludens toxin (Zot) and a hemolysin-coregulated protein gene (hcp) by polymerase chain reaction (PCR). Of the four putative reversible toxin genes, vhh-1 was detected in 31% of the isolates, vhh-2 in 46%, vhh-3 in 23% and vhh-4 was detected in 27% of the isolates. A zot-like sequence of bacteriophage f237 was present in 15%, while hcp sequence was detected in 48% of the isolates. The antimicrobial susceptibility test revealed resistance to several groups
of antibiotics including β-lactams, cephalosporins, macrolides, quinolones, nitrofurantoin and tetracycline. 相似文献
12.
Pravin Kaldhone Rajesh Nayak Aaron M. Lynne Donna E. David Patrick F. McDermott Catherine M. Logue Steven L. Foley 《Applied microbiology》2008,74(16):5038-5046
Salmonella enterica serovar Heidelberg strains are frequently associated with food-borne illness, with recent isolates showing higher rates of resistance to multiple antimicrobial agents. One hundred eighty S. enterica serovar Heidelberg isolates, collected from turkey-associated production and processing sources, were tested for antimicrobial susceptibility and compared by pulsed-field gel electrophoresis (PFGE) and plasmid profile analysis. The potential for the transfer of resistance between strains was studied by conjugation experiments. PFGE analysis using XbaI digestion identified eight clusters (based on 90% similarity), with the largest containing 71% of the isolates. Forty-two percent of the isolates were resistant to at least 1 of the 15 antimicrobial agents tested, and 4% of the isolates were resistant to 8 or more antimicrobial agents. Resistances to streptomycin (32%), tetracycline (30%), and kanamycin (24%) were most commonly detected. Interestingly, the XbaI PFGE profiles of selective multidrug-resistant strains (n = 22) of S. enterica serovar Heidelberg from turkey-associated sources were indistinguishable from the predominant profile (JF6X01.0022) detected in isolates associated with human infections. These isolates were further differentiated into seven distinct profiles following digestion with the BlnI enzyme, with the largest cluster comprising 15 isolates from veterinary diagnostic and turkey processing environments. Conjugation experiments indicated that resistance to multiple antimicrobial agents was transferable among strains with diverse PFGE profiles. 相似文献
13.
Sara E. Gragg Guy H. Loneragan Kendra K. Nightingale Dayna M. Brichta-Harhay Henry Ruiz Jacob R. Elder Lyda G. Garcia Markus F. Miller Alejandro Echeverry Rosa G. Ramírez Porras Mindy M. Brashears 《Applied and environmental microbiology》2013,79(15):4744-4750
Lymph nodes (mandibular, mesenteric, mediastinal, and subiliac; n = 68) and fecal (n = 68) and hide (n = 35) samples were collected from beef carcasses harvested in an abattoir in Mexico. Samples were analyzed for Salmonella, and presumptive colonies were subjected to latex agglutination. Of the isolates recovered, a subset of 91 was characterized by serotyping, pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility phenotyping. Salmonella was isolated from 100% (hide), 94.1% (feces), 91.2% (mesenteric), 76.5% (subiliac), 55.9% (mandibular), and 7.4% (mediastinal) of samples. From the 87 typeable isolates, eight Salmonella enterica serotypes, including Kentucky (32.2%), Anatum (29.9%), Reading (17.2%), Meleagridis (12.6%), Cerro (4.6%), Muenster (1.1%), Give (1.1%), and Mbandaka (1.1%), were identified. S. Meleagridis was more likely (P = 0.03) to be recovered from lymph nodes than from feces or hides, whereas S. Kentucky was more likely (P = 0.02) to be recovered from feces and hides than from lymph nodes. The majority (59.3%) of the Salmonella isolates were pansusceptible; however, multidrug resistance was observed in 13.2% of isolates. Typing by PFGE revealed that Salmonella strains generally clustered by serotype, but some serotypes (Anatum, Kentucky, Meleagridis, and Reading) were comprised of multiple PFGE subtypes. Indistinguishable PFGE subtypes and, therefore, serotypes were isolated from multiple sample types, and multiple PFGE subtypes were commonly observed within an animal. Given the overrepresentation of some serotypes within lymph nodes, we hypothesize that certain Salmonella strains may be better at entering the bovine host than other Salmonella strains or that some may be better adapted for survival within lymph nodes. Our data provide insight into the ecology of Salmonella within cohorts of cattle and offer direction for intervention opportunities. 相似文献
14.
The virulence index of three Meloidogyne incognita field isolates to the resistance gene Rk in cowpea was 0%, 75%, and 120%, with the index measured as reproduction on resistant plants as a percentage of the reproduction on susceptible plants. Continuous culture of the 75% virulent isolate on susceptible tomato for more than 5 years (about 25 generations) resulted in virulence decline to about 4%. The rate of the decline in virulence was described by exponential decay, indicating the progressive loss of virulence on a susceptible host. The 120% virulent isolate declined to 90% virulence during five generations on susceptible cowpea. Following virulence decline, the two isolates were compared over 5 years in inoculated field microplots both separately and as a mixture on susceptible, gene Rk, and gene Rk2 cowpea plants. At infestation of the plots, the two isolates were 1.2% and 92.0% virulent, respectively, to gene Rk and 0.2% and 8.1% virulent, respectively, to gene Rk2. Virulence to gene Rk in the two isolates and in mixture increased under 5 years of continuous Rk cowpea plants to 129% to 172% and under Rk2 cowpea plants to 113% to 139 % by year 5. Virulence to gene Rk2 increased during continuous cropping with Rk cowpea plants to 42% to 47% and with Rk2 cowpea plants to 22% to 48% by year 5. Selection of Rk2-virulence was slower in the isolate with low itt-virulence. The virulence to both genes Rk and Rk2 in the mixed population was not different from that in the highly virulent isolate by year 5 of all cropping combinations. Selection of Rk2-virulence on plants with Rk, and vice versa, indicated at least partial overlap of gene specificity between Rk and Rk2 with respect to selection of nematode virulence. This observation should be considered when resistance is used in cowpea rotations. 相似文献
15.
Roberto Zenteno-Cuevas Francisco X Silva-Hernández Fabiola Mendoza-Damián Maria Dolores Ramírez-Hernández Karen Vázquez-Medina Lorena Widrobo-García Aremy Cuellar-Sanchez Raquel Mu?íz-Salazar Leonor Enciso-Moreno Lucia Monserrat Pérez-Navarro José Antonio Enciso-Moreno 《Memórias do Instituto Oswaldo Cruz》2013,108(6):718-723
Tuberculosis (TB) is an infectocontagious respiratory disease caused by members
of the Mycobacterium tuberculosis complex. A 7 base pair (bp)
deletion in the locus polyketide synthase
(pks)15/1 is described as polymorphic among members of the
M. tuberculosis complex, enabling the identification of
Euro-American, Indo-Oceanic and Asian lineages. The aim of this study was to
characterise this locus in TB isolates from Mexico. One hundred
twenty clinical isolates were recovered from the states of Veracruz and Estado
de Mexico. We determined the nucleotide sequence of a ± 400 bp fragment of the
locus pks15/1, while genotypic characterisation was
performed by spoligotyping. One hundred and fifty isolates contained the 7 bp
deletion, while five had the wild type locus. Lineages X (22%),
LAM (18%) and T (17%) were the most frequent; only three (2%) of the isolates
were identified as Beijing and two (1%) EAI-Manila. The wild type
pks15/1 locus was observed in all Asian lineage isolates
tested. Our results confirm the utility of locus pks15/1 as a
molecular marker for identifying Asian lineages of the M.
tuberculosis complex. This marker could be of great value in the
epidemiological surveillance of TB, especially in countries like Mexico, where
the prevalence of such lineages is unknown. 相似文献
16.
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
17.
C.R. Jackson P.J. Fedorka‐Cray J.A. Davis J.B. Barrett J.H. Brousse J. Gustafson M. Kucher 《Journal of applied microbiology》2010,108(6):2171-2179
Aims: In this study, mechanisms of antimicrobial resistance and genetic relatedness among resistant enterococci from dogs and cats in the United States were determined. Methods and Results: Enterococci resistant to chloramphenicol, ciprofloxacin, erythromycin, gentamicin, kanamycin, streptomycin, lincomycin, quinupristin/dalfopristin and tetracycline were screened for the presence of 15 antimicrobial resistance genes. Five tetracycline resistance genes [tet(M), tet(O), tet(L), tet(S) and tet(U)] were detected with tet(M) accounting for approx. 60% (130/216) of tetracycline resistance; erm(B) was also widely distributed among 96% (43/45) of the erythromycin‐resistant enterococci. Five aminoglycoside resistance genes were also detected among the kanamycin‐resistant isolates with the majority of isolates (25/36; 69%) containing aph(3′)‐IIIa. The bifunctional aminoglycoside resistance gene, aac(6′)‐Ie‐aph(2″)‐Ia, was detected in gentamicin‐resistant isolates and ant(6)‐Ia in streptomycin‐resistant isolates. The most common gene combination among enterococci from dogs (n = 11) was erm(B), aac(6′)‐Ie‐aph(2″)‐Ia, aph(3′)‐IIIa, tet(M), while tet(O), tet(L) were most common among cats (n = 18). Using pulsed‐field gel electrophoresis (PFGE), isolates clustered according to enterococcal species, source and antimicrobial gene content and indistinguishable patterns were observed for some isolates from dogs and cats. Conclusion: Enterococci from dogs and cats may be a source of antimicrobial resistance genes. Significance and Impact of the Study: Dogs and cats may act as reservoirs of antimicrobial resistance genes that can be transferred from pets to people. Although host‐specific ecovars of enterococcal species have been described, identical PFGE patterns suggest that enterococcal strains may be exchanged between these two animal species. 相似文献
18.
Regina Helena Saramago Peralta Jorge Néstor Velásquez Flavia de Souza Cunha María Laura Pantano Fernando Campos Sodré Sidnei da Silva Osvaldo Germán Astudillo José Mauro Peralta Silvana Carnevale 《Memórias do Instituto Oswaldo Cruz》2016,111(1):30-36
The identification and characterisation of Cryptosporidiumgenotypes
and subtypes are fundamental to the study of cryptosporidiosis epidemiology, aiding
in prevention and control strategies. The objective was to determine the genetic
diversity ofCryptosporidium in samples obtained from hospitals of
Rio de Janeiro, Brazil, and Buenos Aires, Argentina. Samples were analysed by
microscopy and TaqMan polymerase chain reaction (PCR) assays
forCryptosporidium detection, genotyped by nested-PCR-restriction
fragment length polymorphism (RFLP) analysis of the 18S rRNA gene and subtyped by DNA
sequencing of the gp60 gene. Among the 89 samples from Rio de
Janeiro, Cryptosporidium spp were detected in 26 by
microscopy/TaqMan PCR. In samples from Buenos Aires,Cryptosporidium
was diagnosed in 15 patients of the 132 studied. The TaqMan PCR and the
nested-PCR-RFLP detected Cryptosporidium parvum,
Cryptosporidium hominis, and co-infections of both species. In
Brazilian samples, the subtypes IbA10G2 and IIcA5G3 were observed. The subtypes found
in Argentinean samples were IbA10G2, IaA10G1R4, IaA11G1R4, and IeA11G3T3, and mixed
subtypes of Ia and IIa families were detected in the co-infections. C.
hominis was the species more frequently detected, and subtype family Ib
was reported in both countries. Subtype diversity was higher in Buenos Aires than in
Rio de Janeiro and two new subtypes were described for the first time. 相似文献
19.
Shanta Dutta Surojit Das Utpala Mitra Priyanka Jain Indranil Roy Shelley S. Ganguly Ujjwayini Ray Phalguni Dutta Dilip Kumar Paul 《PloS one》2014,9(8)
Enteric fever, caused by Salmonella enterica, remains an unresolved public health problem in India and antimicrobial therapy is the main mode of treatment. The objective of this study was to characterize the Salmonella enterica isolates from Kolkata with respect to their antimicrobial resistance (AMR), virulence profiles and molecular subtypes. Salmonella enterica blood isolates were collected from clinically suspected enteric fever patients attending various hospitals in Kolkata, India from January 2009 to June 2013 and were tested for AMR profiles by standard protocols; for resistance gene transfer by conjugation; for resistance and virulence genes profiles by PCR; and for molecular subtypes by Pulsed Field Gel Electrophoresis (PFGE). A total of 77 Salmonella enterica serovar Typhi (S. Typhi) and 25 Salmonella enterica serovar Paratyphi A (S. Paratyphi A) from Kolkata were included in this study. Although multidrug resistance (resistance to chloramphenicol, ampicillin, co-trimoxazole) was decreasing in S. Typhi (18.2%) and absent in S. Paratyphi A, increased resistance to fluoroquinolone, the current drug of choice, caused growing concern for typhoid treatment. A single, non-conjugative non-IncHI1 plasmid of 180 kb was found in 71.4% multidrug resistant (MDR) S. Typhi; the remaining 28.6% isolates were without plasmid. Various AMR markers (bla
TEM-1, catA, sul1, sul2, dfrA15, strA-strB) and class 1 integron with dfrA7 gene were detected in MDR S. Typhi by PCR and sequencing. Most of the study isolates were likely to be virulent due to the presence of virulence markers. Major diversity was not noticed among S. Typhi and S. Paratyphi A from Kolkata by PFGE. The observed association between AMR profiles and S. Typhi pulsotypes might be useful in controlling the spread of the organism by appropriate intervention. The study reiterated the importance of continuous monitoring of AMR and molecular subtypes of Salmonella isolates from endemic regions for better understanding of the disease epidemiology. 相似文献
20.
Intestinal Escherichia coli colonization in a mallard duck population over four consecutive winter seasons
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Ulrike Frömmel Jörg Weinreich Dirk Roggenbuck Sebastian Guenther Katharina Schaufler Christian Schröder Peter Schierack 《Environmental microbiology》2015,17(9):3352-3361
We report the population structure and dynamics of one Escherichia coli population of wild mallard ducks in their natural environment over four winter seasons, following the characterization of 100 isolates each consecutive season. Macro‐restriction analysis was used to define isolates variously as multi‐ or 1‐year pulsed‐field gel electrophoresis (PFGE) types. Isolates were characterized genotypically based on virulence‐associated genes (VAGs), phylogenetic markers, and phenotypically based on haemolytic activity, antimicrobial resistance, adhesion to epithelial cells, microcin production, motility and carbohydrate metabolism. Only 12 out of 220 PFGE types were detectable over more than one winter, and classified as multi‐year PFGE types. There was a dramatic change of PFGE types within two winter seasons. Nevertheless, the genetic pool (VAGs) and antimicrobial resistance pattern remained remarkably stable. The high diversity and dynamics of this E. coli population were also demonstrated by the occurrence of PFGE subtypes and differences between isolates of one PFGE type (based on VAGs, antimicrobial resistance and adhesion rates). Multi‐ and 1‐year PFGE types differed in antimicrobial resistance, VAGs and adhesion. Other parameters were not prominent colonization factors. In conclusion, the high diversity, dynamics and stable genetic pool of an E. coli population seem to enable their successful colonization of host animal population over time. 相似文献