DraI Restriction Research Articles

Molecular Identification of Trichostrongylus Species Among Small Ruminants in Mazandaran Province, Iran

Background: Trichostrongylus is an intestinal parasite that is highly prevalent in humans and livestock worldwide. There is limited information about the prevalence and epidemiology of Trichostrongylus species among the infected livestock in Mazandaran Province, northern Iran. This study aimed to identify Trichostrongylus spp. among small ruminants using morphometric and molecular methods. Materials and Methods: Small intestinal organs of sheep and goats, slaughtered in Mazandaran Province, were examined for infectivity with Trichostrongylus parasites. Primary species identification was conducted based on the morphological characterization of the male worms. The internal transcribed spacer (ITS) II regions of the ribosomal DNA of the worm tissues were amplified using the polymerase chain reaction (PCR) assay and then the product was subjected to sequencing. Subsequently, the PCR products of the ITS II region were subjected to digestion by HinfI and DraI restriction enzymes using the PCR-restriction fragment length polymorphism (RFLP). Results: Of 180 samples, 98 (54.44%) were confirmed positive for Trichostrongylus based on the conventional PCR. The digestion of the PCR products with HinfI and DraI facilitated the identification of three Trichostrongylus species, namely Trichostrongylus colubriformis (35%, 90.81%), Trichostrongylus axei (4%, 4.08%), and Trichostrongylus vitrinus (5%, 5.1%). Both morphometric and RFLP techniques resulted in the differentiation of the three Trichostrongylus species. Conclusion: The present study was the 1st attempt in the last 30 years for the identification of Trichostrongylus species in small ruminants in Mazandaran Province. The findings of this study can be helpful for epidemiological and ecological studies, the establishment of effective control programs, and the management of gastrointestinal parasites in Mazandaran Province.

Short Communication: Prolactin and x-collagen genes polymorphism in Central Javanese local ducks, Indonesia

Abstract. Susanti R, Yuniastuti A. 2020. Short Communication: Prolactin and x-collagen genes polymorphism in Central Javanese local ducks, Indonesia. Biodiversitas 21: 605-610. Genetic conservation is an effective approach to preserve unique and protected species in Indonesia, including indigenous duck (Anas platyrhynchos Linnaeus, 1758). One of the most important things is an identification effort by studying genetic characteristics to support genetic resource conservation programs. This study aim was to analyze the genetic polymorphisms of Central Javanese local duck based on prolactin (PRL) and collagen-x (COLX) genes. A total of 35 local ducks in Central Java was collected as samples, the duck’s calamus feathers were taken for tissue DNA isolation. Polymorphism analysis of PRL and COLX genes were performed using single nucleotide polymorphism (SNP) markers and PCR-RFLP method. The amplicons were then digested with DraI restriction enzyme (AhaIII) (5'TTT/ AAA) for PRL gene, and HaeIII (BsuRI) enzyme (5'GG/ CC-3 ') for COLX gene. The genotype was determined based on RFLP PCR amplicon band results from each target gene. For each gene, data on genotype frequencies, allele frequencies, expected heterozygosities (HE), and Hardy-Weinberg equilibrium were analyzed using PopGene32 software. Based on the PRL gene, there were 25 ducks (71.43%) with BB genotype and 10 ducks (28.57%) with AB genotype. While based on the COLX gene, as many as 25 ducks (71.43%) had TT genotypes, 9 ducks (25.71%) had TC types and 1 duck (1.86%) had CC types. Both PRL and COLX genotypes were clustered the Central Javanese local ducks into 5 haplotypes (A-E). The high allele frequency has belonged to B allele (85.71%) of the PRL gene and T allele (84.25%) of the COLX gene that showed high egg production and quality. Allele B (PRL gene) and T allele (COLX gene) could be predicted as weight eggs’ alleles marker.

Highly GC-rich heterochromatin in chili peppers ( Capsicum -Solanaceae): A cytogenetic and molecular characterization

Abstract Capsicum comprises 35 species of chili peppers and five of them are cultivated worldwide as spices or vegetables. Diploid karyotypes based in x = 12 and x = 13 are common in Capsicum and the constitutive heterochromatin (cHet) is of particular interest in the genus since it is largely variable, particularly its highly GC-rich fraction. However, the repetitive DNA components of this heterochromatic regions are unknown. Given the co-localization of rDNA loci with the CMA+DAPI– heterochromatic bands, we tested the hypothesis that the highly GC-rich cHet fraction is composed of the whole 18S-25S ribosomal DNA (rDNA) unit or some of its components. Here we report on a novel satellite for Capsicum and Solanaceae composed of the complete rDNA unit. We physically mapped six Capsicum derived specific 18S-25S rDNA probes that covered the entire span of the rDNA unit and analysed a DraI restriction product on eight chromosomally different taxa of Capsicum, representative of the major phylogenetic clades of chili peppers. The co-localization of every gene and spacer probes of the 18S-25S rDNA unit suggest their structural function as a major repetitive component of the highly GC-rich cHet in Capsicum species with x = 12. In addition, analyses of the clones derived from restriction assays in C. pubescens suggested that the differential functional status of 18S-25S rDNA loci (nucleolar organizer regions -NORs- or cHet) in this species is related to a divergence in a short sequence upstream the regulatory transcription initiation site (TIS) of the intergenic spacer (IGS). The results here provided evidence that an rDNA mega satellite played a significant role in the evolution of the karyotype features of x = 12 Capsicum species. The finding of a mega satellite family derived from the whole rDNA unit is a novelty for plant genomes.

Molecular Characterization of MSTN Gene in Holstein Friesians and Brown Swiss Cattle Breeds

This research was carried out to investigate polymorphisms of Myostatin gene in Holstein Friesians and Brown Swiss cattle breeds. PCR-RFLP methods were used to investigate of MSTN gene. DraI restriction enzyme were used to detected of MSTN gene polymorphism. The result showed that there were two genotypes (AA and AB) of MSTN gene in two cattle breeds. The allele frequencies in Holstein Friesians was 0.97 and 0.3. while The allele frequencies in brown swiss was 0.88 and 0.12. This result can be used in the future to improve meat properties and growth characteristics in the cattle breeds.

Ankara Tavukçuluk Araştırma Enstitüsü‘nde Yetiştirilen Yumurtacı Saf Tavuk Hatlarında Yumurta Verimi ile İlişkili IGF-I ve NPY Aday Genlerindeki Polimorfizmlerin Belirlenmesi

İnsülin benzeri büyüme faktörü-I (IGF-I) ve nöropeptid Y (NPY) tavuklarda üreme özellikleri ile ilişkili aday genlerdir. Bu çalışmanın amacı Ankara Tavukçuluk Araştırma Enstitüsü‘nde yetiştirilen yumurtacı saf hatlarda IGF-I ve NPY genlerindeki polimorfizmlerin PCR-RFLP yöntemi kullanılarak belirlenmesidir. Bu amaçla IGF-I (5' untranslated region) ve NPY genleri için sırasıyla 621 ve 248 bç büyüklüğündeki bantlar çoğaltılmıştır. PCR ürünleri IGF-I ve NPY genleri üzerindeki tek nükleotid polimorfizmlerini (SNP) belirlemek için sırasıyla PstI ve DraI restriksiyon enzimleri ile kesildi. IGF-I geni için Brown ve D-229 dışındaki tüm hatlar polimorfik bulunmuştur. Kahverengi yumurtacı saf hatlarda IGF-I geni için A allelinin frekansı 0,344 (COL) ile 0,906 (RIRII) aralığında değişirken, beyaz yumurtacı saf hatlarda 0,781 (Maroon) ile 1,000 (D-229, Brown) aralığında bulunmuştur. Bu çalışmada NPY geni için tüm kahverengi yumurtacı saf hatlar polimorfik iken, beyaz yumurtacı tavuk hatlarında sadece Maroon hattı monomorfik bulunmuştur. NPY geni için T allelinin frekansı kahverengi yumurtacılarda 0,200 (BARI) ile 0,985 (COL), beyaz yumurtacılarda ise 0,397 (D-229) ile 1,000 (Maroon) aralığında değişmiştir. Uygulanan ki-kare testine (χ2) göre polimorfik populasyonlarda Hardy-Weinberg dengesinden sapma gözlenmemiştir. Sonuç olarak Ankara Tavukçuluk Araştırma Enstitüsü‘nde yetiştirilen yumurtacı saf hatlarda IGF-I ve NPY genlerindeki polimorfizmler ilk kez gösterilmiştir.

New approach to the mitotype classification in black honeybee Apis mellifera mellifera and Iberian honeybee Apis mellifera iberiensis

The black honeybee Apis mellifera mellifera L. is today the only subspecies of honeybee which is suitable for commercial breeding in the climatic conditions of Northern Europe with long cold winters. The main problem of the black honeybee in Russia and European countries is the preservation of the indigenous gene pool purity, which is lost as a result of hybridization with subspecies, A. m. caucasica, A. m. carnica, A. m. carpatica, and A. m. armeniaca, introduced from southern regions. Genetic identification of the subspecies will reduce the extent of hybridization and provide the gene pool conservation of the black honeybee. Modern classification of the honeybee mitotypes is mainly based on the combined use ofthe DraI restriction endonuclease recognition site polymorphism and sequence polymorphism of the mtDNA COI-COII region. We performed a comparative analysis of the mtDNA COI-COII region sequence polymorphism in the honeybees ofthe evolutionary lineage M from Ural and West European populations of black honeybee A. m. mellifera and Spanish bee A. m. iberiensis. A new approach to the classification of the honeybee M mitotypes was suggested. Using this approach and on the basis of the seven most informative SNPs of the mtDNA COI-COII region, eight honeybee mitotype groups were identified. In addition, it is suggested that this approach will simplify the previously proposed complicated mitotype classification and will make it possible to assess the level of the mitotype diversity and to identify the mitotypes that are the most valuable for the honeybee breeding and rearing.

Practical identification of human originated Lactobacillus species by amplified ribosomal DNA restriction analysis (ARDRA) for probiotic use.

Probiotics are gaining popularity and increasing the importance of their accurate speciation. Lactobacillus species are commonly used as probiotic strains mostly of clinical importance. Present knowledge indicates that at least 14 Lactobacillus species are associated with the human intestinal tract. Currently, researchers are interested in developing efficient techniques for screening and selecting probiotics bacteria, but unfortunately most of these methods are time-consuming, labor-intensive and costly. The aim of this study is to develop reliable, rapid and accurate method to identify 14 references Lactobacillus species that could have been found in the human alimentary tract by 16S ribosomal DNA restriction analysis. In this study, to develop an effective method for the genotype-based identification of the reference Lactobacillus species, 1.5kb of 16S rRNA nucleotide sequences of 14 Lactobacillus were collected from the Gene Bank aligned, in silico restricted and analyzed in respect to their 16S-rRNA restriction fragment polymorphism. In silico restriction profiles of 16S-rRNA indicated that FspBI, HinfI and DraI restriction enzymes (RE) are convenient for differentiation of 14 Lactobacillus species in human intestinal tract except Lb. casei and Lb. paracasei. The patterns of our experimental findings obtained from 16S PCR-ARDRA completely confirmed our in silico patterns. The present work demonstrated that 16S PCR-ARDRA method with FspBI, HinfI and DraI RE is a rapid, accurate and reliable method for the identification of Lactobacillus species from human alimentary tract, especially during the identification of large numbers of isolates and any laboratory equipped with a thermo cycler for probiotic use.

Lack of Association between Polymorphisms of Hepatic Lipase with Lipid Profile in Young Jordanian Adults.

The human hepatic lipase (LIPC) gene encodes hepatic lipase, an enzyme involved in lipoprotein metabolism and regulation. Therefore, variants in LIPC gene may influence plasma lipoprotein levels. In this study, the association of LIPC C-514T and G-250A polymorphisms with plasma lipid profiles in 348 young Jordanians was investigated. Genotyping of C-514T and G-250A was performed by polymerase chain reaction and subsequent digestion with DraI and NiaIII restriction enzymes, respectively, while Roche analyzer was used to determine plasma total cholesterol, triglycerides, low-and high-density lipoprotein. The G-250 and C-514 alleles were most abundant in Jordanians with 79 and 80% frequencies, respectively. Additionally, no difference was found in the lipid–lipoprotein profile between the different genotype groups of C-514T or G-250A polymorphisms, even when males and females were examined separately (P > 0.05). In young Jordanian adults, the examined LIPC polymorphisms seem to play a limited role in determining the lipid profile.

Characterisation of avian Pasteurella multocida strains with PCR-RFLP analysis of the ompH gene

The 16 somatic serotype type strains and 60 field isolates of Pasteurella multocida, representing various avian species and geographic regions in Hungary, were characterised by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of the ompH gene with DraI restriction endonuclease. The type strains yielded eight different (I-VIII) profiles. Strains whose PCR fragment was uncut by DraI (profile IV) could be differentiated with HindIII and PvuII restriction endonucleases. Five of the eight PCR-RFLP profiles (I, III, V, VI and VII) were detected among the field strains. Only a correlation of limited strength was found between the classical somatic serotypes and the PCR-RFLP profiles. However, the results confirmed that molecular methods could confidently distinguish serotype A:1 strains from the other serotypes. Moreover, the specific relationship between somatic serotypes and PCR-RFLP types among isolates from turkey raises the possibility of the existence of host-specific clones within the P. multocida population.

DETECTION OF PEAR S-ALLELES BY SETTING UP A REVISED IDENTIFICATION SYSTEM

Pear (Pyrus communis L.) cultivars are self-incompatible and their adequate fruit set depends on the presence of pollinizer trees with compatibility of bloom period and alleles. This research was carried out in order to identify the self-incompatibility alleles in pear cultivars of the Iranian National Pear Collection. Partial or complete sequences of more than 200 pear S-alleles have been obtained from NCBI and aligned by ClustalW2 in order to compare their conserved regions for categorization of the sequences and subsequent primer design. All deposited S-alleles were separated based on the original species and sequence in 63 divergent sequences, and C2 and C3 conserved regions were used for FB-F/FB-R2 non-specific primer designing. Following PCR amplification of S-alleles, DraI, EcoRI, MspI and HaeIII restriction maps of amplified regions were compared to expected maps from previously identified S-alleles. The results showed homonym groups of alleles, also synonymous alleles such as S22 and S3 in the data bank. Detection of S-alleles in pear cultivars demonstrated 21, 10.5, 13.1 and 7.8% of frequencies, respectively for S1, S2, S4 and S5 alleles. Interestingly, the S42 rare allele from P. ussuriensis was detected in cultivar 'Konjuni' originating from central areas of Iran.

Search Region of Origin Honey Bee A. mellifera in Indonesia Region Using Mitochondrial DNA intergenic cox1/cox2

Apis mellifera is a favourite honey bee for the beekeepers throughout many countries. This species comprise of 24 subspecies. Based on phylogeography and morphometric evidences, these subspecies have been grouped into four lineage; namely the African (A), Western and Northern Europe (M), Southeastern Europe (C), and Near Eastern (O). Apis mellifera have been imported to Indonesia since 1972, and mostly from Australia. However, until recently there are no data about the A. mellifera subspecies and the origin. Therefore the objective of this research is to determine the lineage of A. mellifera in Indonesia based on mtDNA intergenic region between cox1/cox2 genes. In this region there are two DNA fragments, P and Q fragnant, that can be used to determine the A. mellifera lineage. The methodology used consist of samples collection, DNA isolation, DNA amplification, DNA restriction using DraI enzyme, DNA sequencing, and DNA alignment using Clustal X and MEGA spftwares. DNA fragment amplified by using E2 and H1 primer revealed a 863 bp. Digestion of the region with the DraI restriction enzyme revealed one haplotype, which consist of five DNA fragments. Based on DNA sequences and DNA alignment, A. mellifera in Indonesia was homologue with the C lineage . Its subspecies is A. m. ligustica that lived natively in Italy, they were imported to Indonesia from Australia

Comparative molecular analysis of Fusarium solani isolates by RFLP and RAPD

Fusarium solani is an important pathogen causing wilt disease of guava in India. In this work, we analyzed seven representative isolates of F. solani, collected from different places of India, by restriction fragment length polymorphism (RPLP) using HindIII or DraI restriction endonucleases and random amplified polymorphic DNA (RAPD). Pattern of restriction enzyme revealed a similar restriction cut type cluster in the isolate namely, Allahabad (isolate-3), Faizabad (isolate-4), Unnao (isolate-5) and Lucknow (isolate-6) region, while other cluster was consist of isolate from Ranchi (isolate-2) and Ludhiana (isolate-7). Slightly variable results were obtained when 10 randomly amplified polymorphic DNA markers (OPA01–OPA10) tested in the genome of Fusarium solani and grouped on basis of obtained allelic data. RAPD fingerprinting showed a higher variability than RFLP, and each isolate had a unique electrophoretic pattern with five of the ten primers used. Our results show that RAPD much efficient to distinguish between all F. solani isolate tested.

Mitochondrial DNA Variation in the CoxI–CoxII Intergenic Region among Turkish and Iranian Honey Bees (Apis mellifera L.)

The western honey bee, Apis mellifera L., is native to Africa, the Near and Middle East, and Europe. Based on morphometrics, the Near Eastern subspecies, Anatolian (A. m. anatoliaca), Caucasian (A. m. caucasica), and Iranian (A. m. meda), were grouped within the Middle Eastern O branch (Ruttner 1988; Kauhausen-Keller et al. 1997); however, mtDNA analysis has shown that they belong to the East Mediterranean C lineage (Smith et al. 1997; Palmer et al. 2000; Franck et al. 2000, 2001; Kandemir et al. 2006; Ozdil et al. 2009). According to Ruttner’s (1988) morphometric analysis, A. m. anatoliaca occupies nearly all of Turkey, A. m. caucasica is found in the northeastern part of Turkey, and A. m. meda is found primarily in Iran but also in the southeastern part of Turkey. Length and restriction site polymorphisms within the CoxI–CoxII intergenic region of the honey bee mitochondrial genome have been particularly useful in differentiating evolutionary lineages and groups of subspecies (Cornuet and Garnery 1991; Hall and Smith 1991; Garnery et al. 1992, 1993; Franck et al. 2000, 2001; Palmer et al. 2000). For example, DraI restriction of this region revealed more than 50 haplotypes in lineages A and M (Garnery et al. 1992, 1993; Franck et al. 2000, 2001) but only six haplotypes in lineage C (Franck et al. 2000; Kandemir et al. 2006; Ozdil et al. 2009), including one discovered recently (Ozdil et al. 2009).

Genetic Characterization of Commercial Honey Bee (Hymenoptera: Apidae) Populations in the United States by Using Mitochondrial and Microsatellite Markers

Abstract Genetic diversity levels within and between the two commercial breeding areas in the United States were analyzed using the DraI restriction fragment length polymorphism of the COI-COII mitochondrial region and 10 polymorphic microsatellite loci. The western commercial breeding population (WCBP) and the southeastern commercial breeding population (SCBP) were sampled in 1993–1994 and again in 2004–2005. The goal of this study was to characterize the genetic composition of these populations and to measure potential changes in genetic diversity and composition across the sampling period. The mitochondrial DNA haplotypes C1 and C2, characteristic of the most popular bee strains (Italians and Carniolans, respectively) sold in the United States, were the dominant haplotypes at both sample dates. The frequency of Apis mellifera mellifera M haplotypes, M4, M7, and M7′, decreased during the 10-yr span. An A1 haplotype characteristic of Africanized bees was found in the SCBP from 2005. Microsatellite analysis showed there was a loss of alleles in both the WCBP and SCBP, but the losses were not significant due to simultaneous gains of new alleles into these populations between 1993 and 2005. Genetic differences that occurred between the 1993–1994 WCBP and SCBP were still detectable in these populations sampled a decade later, suggesting that these populations could be useful sources of diversity for each other in the future.

Molecular Genetic Characterization of the Merozoite Surface Protein 1 Gene of Plasmodium vivax from Reemerging Korean Isolates

Plasmodium vivax merozoite surface protein 1 (PvMSP-1) has been considered a major candidate for the development of an antimalaria vaccine, but the molecule exhibits antigenic diversity among isolates. The extent of genetic polymorphism in the region between interspecies conserved blocks 4 and 5 (ICB4 and ICB5) of the PvMSP-1 gene was analyzed for 30 Korean isolates. Two genotypes, SK-A and SK-B, were identified on the basis of amino acid substitution. Almost all the amino acid sequences of the Korean isolates were nearly identical to those of the Solomon Island isolate Solo-83 (97.8 to 99.9% similarity) and Philippine isolates Ph-79, Ph-52-2, and Ph-49 (97.3 to 99.8% similarity). Also, we report two sequences in the isolates that were characterized on the basis of restriction fragment length polymorphism (RFLP). The RFLP profiles following digestion with the DraI restriction enzyme produced two distinguishable patterns. This study might be the first report of the region between ICB4 and ICB5 of the MSP-1 gene of P. vivax in South Korea.

Mitochondrial DNA support for genetic reserves of Apis mellifera/syriaca in Jordan

SummaryWe analyzed mitochondrial DNA variation in honey bee colonies in Jordan using DraI restriction profiles of the COI-COII intergenic region. Seven different haplotypes were observed, three of which belonged to the C mitochondrial lineage. Samples displaying haplotypes of the C lineage were concentrated in the north of the country where frequent importations of European bees have occurred. We conclude that the C mitochondrial haplotypes found in the study reflect past or recent importations of non-native honey bees. No C haplotypes were detected in areas that have been identified as possible source populations for the conservation of original A. m. syriaca in the south of the sampling region, thus confirming the existence of comparatively pure genetic resources of this subspecies in Jordan.

Morphometric and genetic variability of honey bee (Apis mellifera L.) populations from northern Iran

SummarySamples from seven honey bee populations; five Apis mellifera meda from Iran and two from Turkey, one belonging to A. m. meda and one to A. m. caucasica, were investigated using morphometric, mtDNA, and microsatellite analyses. Morphometric analysis revealed three distinct clusters. The first included all Iranian populations, whilst the second and third contained the meda and caucasica bees from Turkey. No variation was observed in the DraI restriction of COI-COII intergenic region in mitochondrial DNA, yielding a single C lineage mitotype. The analysis of microsatellite loci, A7, A24, A28, A43 and A113 revealed, a considerable level of genetic diversity, with average expected heterozygosity ranging from 0.596±0.188 to 0.695±0.174 and average number of alleles per locus from 4.4 to 8.0 among Iranian honey bee populations.

Visualization of the Detailed Structure of Plasmid DNA

We report results from scanning tunneling microscopy experiments in which supercoiling of the plasmid, pTNT, leads to localized duplex denaturation at a single location. Measurements of the imaged strand-separated region suggest an extent of approximately 60 base pairs (bp's), in excellent agreement with the prediction of a statistical mechanical analysis of the pTNT base sequence that accounts for the topology-mediated global coupling of melting behaviors. Notwithstanding that the sequence of pTNT includes a 30-bp run of poly-A, where thermodynamic considerations alone predict significant instability, based on the statistical result, we propose the location of denaturation is an approximately 60-bp run, spanning positions 2050-2110, that is 82% AT-rich, terminally flanks the beta-lactamase coding region, and is known to contain two sites susceptible to cleavage by the DraI restriction enzyme.

Comparison of the Spirochete Borrelia burgdorferi S. L. Isolated From the Tick Ixodes scapularis in Southeastern and Northeastern United States

Thirty-five strains of the Lyme disease spirochete Borrelia burgdorferi sensu lato (B. burgdorferi s. l.) were isolated from the blacklegged tick vector Ixodes scapularis in South Carolina, Georgia, Florida, and Rhode Island. They were characterized by PCR-restriction fragment length polymorphism (RFLP) analysis of rrf (5S)-rrl (23S) intergenic spacer amplicons. PCR-RFLP analysis indicated that the strains represented at least 3 genospecies (including a possible novel genospecies) and 4 different restriction patterns. Thirty strains belonged to the genospecies B. burgdorferi sensu stricto (B. burgdorferi s. s.), 4 southern strains were identified as B. bissettii, and strain SCCH-5 from South Carolina exhibited MseI and DraI restriction patterns different from those of previously reported genospecies. Complete sequences of rrf-rrl intergenic spacers from 14 southeastern and northeastern strains were determined and the phylogenetic relationships of these strains were compared. The 14 strains clustered into 3 separate lineages on the basis of sequence analysis. These results were confirmed by phylogenetic analysis based on 16S rDNA sequence analysis.

Achromobacter xylosoxidans respiratory tract infections in cystic fibrosis patients

Achromobacter xylosoxidans is a ubiquitous Gram-negative non-fermenting rod, recently characterized as an emerging pathogen in cystic fibrosis (CF) patients. Its pathogenic potential and prevalent transmission routes are still unclear. This study investigated the PFGE genetic pattern and antimicrobial resistance profile of 42 A. xylosoxidans isolates obtained over 4 years from the respiratory tract of 22 CF patients. By genotypic analysis, 31 isolates were attributed to 8 distinct PFGE patterns (A-H), whereas 11 isolates were not typable because their DNA was not restricted by XbaI and DraI restriction enzymes. The majority of the isolates showed multidrug resistance; imipenem and piperacillin were the most active drugs. During the course of A. xylosoxidans chronic infection forced expiratory volume and body mass index values were not significantly lowered. The demonstration of widespread antibiotic resistance underscores the importance of antibiogram-directed therapy. Our data suggest that in some cases the infection may have been acquired from other patients or from a common contaminated source. Further epidemiological studies may be important for the design and implementation of prophylactic measures in CF centers.