Discrimination Of Genotypes Research Articles

Genetic diversity of Santalum album using random amplified polymorphic DNAs

Santalum album is a parasitic, evergreen tree growing primarily in south Central India, in the dry forest of the Decan plateau. Sandalwood is found distributed all over the country with over 90% of the area in Karnataka and Tamil Nadu. It is of great economic importance because of its fragrant heartwood and oil. In the present study Random Amplified Polymorphic DNA (RAPD) technique was used to accesses the genetic diversity among 30 accessions of S. album collected from different parts of South India. A total of 248 polymorphic amplicons were obtained from 30 primers. The value of Jaccard coefficient ranged from 0.66 to 0.99. Similarity results indicated the high level of genetic diversity existing in S. album. Cluster analysis using UPGMA separated the accession into 2 major groups. These results promote the initiative to integrate this RAPD markers in the discrimination of genotypes which can be exploited in the improvement of S. album.

Occurrence of Mycobacterium avium subspecies paratuberculosis across host species and European countries with evidence for transmission between wildlife and domestic ruminants

BackgroundMycobacterium avium subspecies paratuberculosis (Map) causes an infectious chronic enteritis (paratuberculosis or Johne's disease) principally of ruminants. The epidemiology of Map is poorly understood, particularly with respect to the role of wildlife reservoirs and the controversial issue of zoonotic potential (Crohn's disease). Genotypic discrimination of Map isolates is pivotal to descriptive epidemiology and resolving these issues. This study was undertaken to determine the genetic diversity of Map, enhance our understanding of the host range and distribution and assess the potential for interspecies transmission.Results164 Map isolates from seven European countries representing 19 different host species were genotyped by standardized IS900 - restriction fragment length polymorphism (IS900-RFLP), pulsed-field gel electrophoresis (PFGE), amplified fragment length polymorphisms (AFLP) and mycobacterial interspersed repeat unit-variable number tandem repeat (MIRU-VNTR) analyses. Six PstI and 17 BstEII IS900-RFLP, 31 multiplex [SnaBI-SpeI] PFGE profiles and 23 MIRU-VNTR profiles were detected. AFLP gave insufficient discrimination of isolates for meaningful genetic analysis. Point estimates for Simpson's index of diversity calculated for the individual typing techniques were in the range of 0.636 to 0.664 but a combination of all three methods increased the discriminating power to 0.879, sufficient for investigating transmission dynamics. Two predominant strain types were detected across Europe with all three typing techniques. Evidence for interspecies transmission between wildlife and domestic ruminants on the same property was demonstrated in four cases, between wildlife species on the same property in two cases and between different species of domestic livestock on one property.ConclusionThe results of this study showed that it is necessary to use multiple genotyping techniques targeting different sources of genetic variation to obtain the level of discrimination necessary to investigate transmission dynamics and trace the source of Map infections. Furthermore, the combination of genotyping techniques may depend on the geographical location of the population to be tested. Identical genotypes were obtained from Map isolated from different host species co-habiting on the same property strongly suggesting that interspecies transmission occurs. Interspecies transmission of Map between wildlife species and domestic livestock on the same property provides further evidence to support a role for wildlife reservoirs of infection.

Comparative Analysis of RAPD and ISSR Markers for Characterization of Sesame (Sesamum indicum L) Genotypes

The determination of genetic differences among crop genotypes has become the primary need to grant patent and the protection of Plant Breeder Rights (PBR). In the present study RAPD and ISSR markers were employed for the characterization of 16 sesame genotypes. Twenty six RAPD and 17 ISSR primers that generated clear and reproducible banding patterns amplified 194 and 163 bands, respectively among 16 sesame genotypes. Both RAPD and ISSR primers showed maximum discrimination power, and produced putative variety specific bands, which could be used for the identification of all the sesame genotypes, individually. However, only AG and CA based ISSR primers were found effective in the discrimination of genotypes. A poor correlation was observed between the matrices produced by RAPD and ISSR primers, which might be due to the array of different sites of the genome. Though, there was greater similarity among sesame genotypes (0.78 for RAPD and 0.71 for ISSR), the observed genetic diversity (0.22 for RAPD and 0.29 for ISSR), was found effective for the characterization of sesame genotypes. It is suggested that putative variety specific RAPD and ISSR markers could be converted to Codominant sequence characterized amplified region/sequence tagged site (SCAR /STS) markers to develop robust variety specific markers.

Consistency of genotypic performance of lowland rice in wet and dry season in Lao PDR

Lowland rice in Laos as in some other SE Asian countries is grown mostly under rainfed conditions in wet season (WS), but some crops are grown under irrigated conditions in dry season (DS). In Laos, the rice breeding program is concentrating on development of photoperiod insensitive varieties which can be grown in both WS and DS, nevertheless most selection is conducted in WS. In order to determine consistency of genotypic performance between WS and DS, 23 advanced breeding lines and varieties were grown in both seasons for 2–3 years at four locations in the country. All experiments in DS showed significant genotypic variation for grain yield, while genotypic variation was smaller and often not significant in each experiment in WS. The heritability was also higher in DS than in WS. Significant genotype-by-environment interaction was found, and some of this interaction was due to long duration genotypes being affected by extreme temperature conditions in DS particularly at a high altitude location in Northern Laos. Cluster analyses indicate that the genotypic discrimination was large in experiments with intermediate yield levels (mean yield of 2.9–3.8 t/ha). It is concluded that the use of DS trials should be increased to improve the efficiency of selection for widely adapted varieties in the lowland rice breeding program in Laos and other countries of similar growing conditions.

OBJECTIVE EVALUATION MEASURES OF GENETIC MARKER SELECTION IN LARGE-SCALE SNP GENOTYPING

High-throughput single nucleotide polymorphism (SNP) genotyping systems provide two kinds of fluorescent signals detected from different alleles. In current technologies, the process of genotype discrimination requires subjective judgments by expert operators, even when using clustering algorithms. Here, we propose two evaluation measures to manage fluorescent scatter data with nonclear plot aggregation. The first is the marker ranking measure, which provides a ranking system for the SNP markers based on the distance between the scatter plot distribution and a user-defined ideal distribution. The second measure, called individual genotype membership, uses the membership probability of each genotype related to an individual plot in the scatter data. In verification experiments, the marker ranking measure determined the ranking of SNP markers correlated with the subjective order of SNP markers judged by an expert operator. The experiment using the individual genotype membership measure clarified that the total number of unclassified individuals was remarkably reduced compared to that of manually unclassified ones. These two evaluation measures were implemented as the GTAssist software. GTAssist provides objective standards and avoids subjective biases in SNP genotyping workflows.

Characterization of Tomentosa cherry ( Prunus tomentosa Thunb.) genotypes using SSR markers and morphological traits

A collection of 44 Tomentosa cherry ( Prunus tomentosa Thunb.) accessions from 10 eco-geographical regions was evaluated using morphological descriptors. Ten quantitative and eight qualitative traits were analyzed and significant differences among populations were found for most traits. The highest variation observed was in fruit weight, fruit width and leaf width. P. tomentosa is distributed in at least five northern Chinese provinces and different accessions have their own specific morphological features. It was possible to identify several highly distinct accessions based on morphological characters. Genetic variation among the 44 Tomentosa cherries and 7 accessions from 3 related species ( P. humilis, P. japonica and P. glandulosa) was characterized by simple sequence repeat (SSR) markers developed from peach, sweet cherry, sour cherry and apricot. Forty-four out of 110 SSR markers (40%) could be transferred to Tomentosa cherry and the other 3 species. A total of 250 alleles were detected with an average of 5.68 alleles per locus and an average polymorphism information content of 0.52. The results demonstrated the cross-species transferability of SSR primers developed in cultivated species to wild species in Prunus for the discrimination of different genotypes. Unweighted pair group method with arithmetic average (UPGMA) analysis of SSR data clustered the P. humilis, P. japonica and P. glandulosa into one group and the accessions of P. tomentosa into another parallel group with strong bootstrap support (93–100%). Within P. tomentosa, the weeping accessions formed a subgroup and the rest formed several groups that generally reflected their geographical origins.

Genetic diversity and phylogenic relationships in date-palms ( Phoenix dactylifera L.) as assessed by random amplified microsatellite polymorphism markers (RAMPOs)

Random amplified microsatellite polymorphisms (RAMPOs) were used to assess genetic diversity among 30 date-palm cultivars and 10 male trees. Using 18 primers combinations, 197 bands were scored and 186 were polymorphic suggesting the high level of polymorphism among studied cultivars. Moreover, taking into account the high percentage of polymorphic bands (ppb), the resolving power ( R p) together with the polymorphism information content (PIC) scored values, all the tested primer sets contribute strongly in the discrimination of date-palm genotypes. In addition, the topology of the derived UPGMA dendrogram exhibited cultivars’ clustering made independently both from the geographical origin and/or from the sex of trees. The present data support the Mesopotamian origin of the date-palm domestication. Thus we assume that the used method is efficient to assess genetic diversity within date-palm cultivars. Data are discussed in relation with the opportunity of the RAMPO method to provide additional molecular markers suitable in the improvement of the date-palms germplasm characterisation.

Determination of Mega‐Environments for Peanut Breeding Using the CSM‐CROPGRO‐Peanut Model

Breeding for locally adapted cultivars requires a subdivision of the target region into mega‐environments. Crop models could assist in generating the required data for mega‐environment determination. The objective of this study was to determine whether subdividing the peanut (Arachis hypogaea L.) production areas in Thailand into mega‐environments using a crop simulation model would be justified. The Cropping System Model (CSM) CROPGRO‐Peanut was used to simulate pod yield of 17 diverse peanut lines for 130 locations covering all peanut production areas in Thailand. The data were statistically analyzed, and the genotype and genotype × environment (GGE) biplot method was used to subdivide the peanut production areas into subregions. The results reveal that the genotype × location interaction accounted for only a small proportion of total yield variation for all years. The analyses of yearly data by the GGE biplot shows inconsistent results across years for location grouping as well as for the winning genotypes of the individual location‐groups. The GGE biplot analysis of the mean data over 30 yr also indicates a similarity in genotype discrimination for all the locations. The results from this study show that the subdivision of peanut production areas into mega‐environments is not justified for Thailand. Therefore, for peanut breeding, Thailand should be considered as one mega‐environment.

Location Contributions Determined via GGE Biplot Analysis of Multienvironment Sugarcane Genotype‐Performance Trials

Selection for productive sugarcane (Saccharum spp.) cultivars in Florida has been more successful for organic than for sand soils. The objectives of this study were to assess the contributions of a sand‐soil location to the final stage of multienvironment testing of sugarcane genotypes in Florida, and to identify locations with organic soils that, if replaced with a sand‐soil location, would be least likely to compromise superior cultivar selection for organic soils in Florida. Sixteen genotypes were harvested in two or three crop cycles from 2002 to 2005 at nine locations. Traits analyzed were cane and sucrose yields (Mg ha−1) and theoretical recoverable sucrose (TRS) (g kg−1). The sand‐soil location, Lykes, was generally neither highly representative of locations nor highly discriminating of genotypes. Results revealed the desirability of replacing an organic‐soil location with a sand‐soil location in the final testing stage of this sugarcane breeding and selection program. Caution must be exercised, however, to ensure that such action would not compromise genotype discrimination for TRS and sucrose yield. Ability to identify productive cultivars on organic soils by the Florida sugarcane selection program would be least compromised by replacing either Osceola or Knight with a sand‐soil location.

Assessing for genetic and environmental effects on ruminant feed quality in barley (Hordeum vulgare)

Grain samples from a combined intermediate and advanced stage barley breeding trial series, grown at two sites in two consecutive years were assessed for detailed grain quality and ruminant feed quality. The results indicated that there were significant genetic and environmental effects for “feed” traits as measured using grain hardness, acid detergent fibre (ADF), starch and in-sacco dry matter digestibility (ISDMD) assays. In addition, there was strong genotypic discrimination for the regressed feed performance traits, namely Net Energy (NE) and Average Daily Gain (ADG). There was considerable variation in genetic correlations for all traits based on variance from the cultivars used, sites or laboratory processing effects. There was a high level of heritability ranging from 89% to 88% for retention, 60% to 80% for protein and 56% to 68% for ADF. However, there were only low to moderate levels of heritability for the feed traits, with starch 30–39%, ISDMD 55–63%, ADF 56–68%, particle size 47–73%, 31–48% NE and ADG 44–51%. These results suggest that there were real differences in the feed performance of barleys and that selection for cattle feed quality is potentially a viable option for breeding programs.

Application of metabolomics to genotype and phenotype discrimination of birch trees grown in a long-term open-field experiment

The principal objectives of the study were to develop metabolomics tool and to test its efficiency for discrimination and biochemical pattern recognition of genotypes and phenotypes of silver birch trees (Betula pendula Roth). In the experiment were used two birch genotypes (GT 2 and GT 5) that have been grown over seven years on the two open fields A and B. The metabolomics tool was applied also to study biochemical responses of the GT 2 to elevated (1.5 × ambient) concentration of ozone as an environmental stress factor. These trees were treated with ozone over seven years using an open-air exposure system. The developed metabolomics tool was based on the analyses of lipophilic and polar compounds of birch leaves with GC-MS and HPLC-DAD (polar phenolics only). The metabolome database included 331 chemical traits and was analyzed with descriptive and multivariate statistics. Application of cluster and principle component analyses clearly discriminated genetically different birch trees. In addition, the genotype clusters were further divided into two subclusters corresponding to trees from field A and field B. Formation of these phenotypes was due to the differences in some environmental conditions between the field A and field B. Biochemical discrimination between phenotypes of control and ozone-treated birch trees of GT 2 was found also. However, distances between these phenotypes, as well as between phenotypes of control trees from the field A and field B were found to be considerably smaller than between birch genotypes. Metabolites with the largest contribution to birch genotype/phenotype discrimination were determined and some were identified.

N605ab, a specific molecular marker for Phytophthora infestans, distinguishes three genotypes in Japan

Random amplified polymorphic DNA (RAPD) analysis using the OPG-06 primer generated specific patterns for Japanese genotypes US-1, JP-1, and a new A1 (JP-2, JP-3, and JP-4) of Phytophthora infestans. N605, a specific RAPD fragment, was cloned and sequenced. PCR primers BD1/BD2 were constructed based on the N605 sequence and were used to clarify the genotypes. PCR products using the BD1/BD2 primers (N605ab marker) easily distinguished the new A1 from US-1 and JP-1. This technique provides a simple and effective method for rapid genotype discrimination that can be used in ecological experiments and forecasts for the occurrence of late blight.

Sequence Polymorphism Systems for Quantitative Real-Time Polymerase Chain Reaction to Characterize Hematopoietic Chimerism—High Informativity and Sensitivity As Well As Excellent Reproducibility and Precision of Measurement

Sequence polymorphisms (SPs) can serve as genetic markers for quantitative polymerase chain reactions (qPCR) for chimerism analysis, providing a significantly higher sensitivity compared to short tandem repeat PCR. In this study, a panel of 29 selected markers was evaluated in 317 patients with leukemia and myelodysplastic syndrome, who received allogeneic stem cell transplantation. In total, 5415 posttransplantation samples were analyzed. Recipient genotype discrimination was possible in 96% with a mean number of 2.5 (1-7) informative markers per recipient/donor pair. Marker specific standard dilution series from volunteers' DNA served as standard for quantification of chimerism. Sensitivity of the method was < or =1 x 10-3 (0.1% of recipient cells) in 83.3% of the assays. By this method, it was possible to very accurately detect autologous signals in the range from 0% to 0.5% (95% confidence interval [CI] +/-0.2), from 0.5% to 1% (95% CI +/-0.4), from 1% to 2% (95% CI +/-0.6) and from 2% to 5% (95% CI +/-1.2). Reproducibility of the quantified autologous signals was independent from the amount of DNA. This is the first report on a SP-based chimerism system allowing for the performance of chimerism analyses for virtually all patients with high sensitivity, excellent reproducibility, and precision of measurement.

Asian Pacific Association for the Study of the Liver consensus statements on the diagnosis, management and treatment of hepatitis C virus infection

Asian Pacific Association for the Study of the Liver consensus statements on the diagnosis, management and treatment of hepatitis C virus infection

Potato varietal discrimination using ground based multiband radiometer

The potential usefulness of spectral properties and vegetation indices in varietal discrimination of potato genotypes was studied in the field experiment. Spectral measurements were recorded in different bands in blue (450–520 nm), green (520–590 nm), red (620–680 nm) and infrared (770–860 nm) of the electromagnetic spectrum at different stages during crop growth period. A ground based hand held multiband radiometer (Model/041) was used for the purpose. The mean per cent green reflectance value among different genotypes was lowest in genotype MS/86-89, while it was observed highest in genotype JX-216. Significant difference among these genotypes was found at all growth stages except 6 week after planting. Consequent to variation in spectral reflectance the vegetation indices like, NDVI, RVI, TVI and DVI showed significant difference among genotypes at all growth stages except at 8th week after planting. The vegetation indices are good indicators of crop growth and condition. Similarly, fresh weight, dry weight, and leaf area index were also highest in MS/86-89, followed by KUFRI Bahar and KUFRI Sutlej while in case of leaf area index it was followed by Kufri Sutlej and Kufri Bahar. JX-23 was highest in chlorophyll content and tuber yield followed by MS/86-89 and JW-160, while lowest chlorophyll content was seen in MS/89-1095 and poorest tuber yield in MS/89-60. Most of the genotypes exhibited considerable variation in their spectral response and vegetation indices thereby indicating the possibility of their discrimination through remote sensing technique.

Genetic diversity in ecotypes of Tunisian date-palm (Phoenix dactylifera L.) assessed by AFLP markers

SummaryAmplified fragment length polymorphisms (AFLP) were used successfully to survey genetic diversity in 40 ecotypes of date-palm (Phoenix dactylifera L.) collected from oases in Tunisia. Six primer pairs were screened to assess their ability to detect polymorphism in this tree crop. As a result, a total of 428 AFLPs have been generated and used to estimate genetic distances which ranged from 0.07 – 0.63. A large, and typically continuous, range of genetic diversity characterises Tunisian date-palm germplasm. In addition, the UPGMA dendrogram derived from these data exhibited two clusterings of ecotypes independent of their geographic origin or the sex of the trees. These data corroborate the hypothesis of the origin of date-palm domestication being in Mesopotamia. Moreover, taking into account the high percentage of polymorphic bands, together with their resolving power (Rp), all the primer pairs tested contributed to the discrimination of date-palm genotypes, suggesting that the AFLP method is efficient in assessing genetic diversity in this crop. The data are discussed in relation to the use of AFLP molecular markers in the management and improvement of date-palm.

Identification and Characterization of Bacterial Pathogens Causing Bloodstream Infections by DNA Microarray

Bloodstream infections are potentially life-threatening and require rapid identification and antibiotic susceptibility testing of the causative pathogen in order to facilitate specific antimicrobial therapy. We developed a prototype DNA microarray for the identification and characterization of three important bacteremia-causing species: Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The array consisted of 120 species-specific gene probes 200 to 800 bp in length that were amplified from recombinant plasmids. These probes represented genes encoding housekeeping proteins, virulence factors, and antibiotic resistance determinants. Evaluation with 42 clinical isolates, 3 reference strains, and 13 positive blood cultures revealed that the DNA microarray was highly specific in identifying S. aureus, E. coli, and P. aeruginosa strains and in discriminating them from closely related gram-positive and gram-negative bacterial strains also known to be etiological agents of bacteremia. We found a nearly perfect correlation between phenotypic antibiotic resistance determined by conventional susceptibility testing and genotypic antibiotic resistance by hybridization to the S. aureus resistance gene probes mecA (oxacillin-methicillin resistance), aacA-aphD (gentamicin resistance), ermA (erythromycin resistance), and blaZ (penicillin resistance) and the E. coli resistance gene probes blaTEM-106 (penicillin resistance) and aacC2 (aminoglycoside resistance). Furthermore, antibiotic resistance and virulence gene probes permitted genotypic discrimination within a species. This novel DNA microarray demonstrates the feasibility of simultaneously identifying and characterizing bacteria in blood cultures without prior amplification of target DNA or preidentification of the pathogen.

Carbon isotope discrimination of two-rowed and six-rowed barley genotypes under irrigated and non-irrigated field conditions

Carbon isotope discrimination (Δ) has been widely used to estimate the water-use efficiency (WUE) of C3 cereals including barley (Hordeum vulgare L.). Genetic lines of barley belong to two phenotypic classes for ear morphology, either two-rowed or six-rowed, a simply inherited trait. We tested the value of Δ as a predictor of grain yield and WUE for these two types of barley under different conditions of water availability. We also investigated if differences in plant morphology and yield parameters between these two types resulted in different carbon dynamics and different Δ values for grain, awn and flag leaf. We conducted field experiments for 3 consecutive years with genetic lines of both ear types in northern Utah and southeastern Idaho under irrigated and non-irrigated conditions, including two line-source sprinkler experiments. Correlations between grain yield and Δ values of flag leaf, awn and grain were stronger in combined analyses across ear types than in analyses within two-rowed (2R) and six-rowed (6R) types. Nevertheless, we found that Δ of mature awns and grains were a good predictor of yield for both barley types under low to moderate water stress. However, Δ was not a reliable predictor for barley yield under severe water stress. Pearson’s correlations were used to test associations between Δ values and several yield parameters (heading date, above-ground dry matter, harvest index, grain mass per fertile tiller). Our data indicated that among the field-grown genetic lines tested, the two types of barley differed in Δ values for grain, awn and flag leaf. Values of Δ for 2R barley were usually lower, suggesting higher WUE, than those for 6R types. Fundamental differences in sink size or grain mass per fertile tiller between 2R and 6R cultivars probably have important consequences on carbon/water metabolism at the whole tiller level. Key words: Barley, carbon isotope discrimination, yield, awn, drought, irrigation

Optimizing Controlled Environment Assessment of Levels of Resistance to Yam Anthracnose Disease Using Tissue Culture‐derived Whole Plants

AbstractStudies were conducted to determine the timing and frequency of disease assessment required to effectively identify levels of resistance to yam anthracnose using tissue culture‐derived whole plant inoculation assay. The effects of inoculation methods (paint brush and spray), and disease scoring methods [individual leaf area (ILA) and whole plant area (WPA)] were also assessed. Spray inoculation resulted in rapid infection and higher variations among yam genotypes, leading to earlier discrimination of genotypes than with the paintbrush method. Both the ILA and WPA scoring methods showed variation among yam genotypes, and association between the two methods gave a high positive correlation (r &gt; 0.90). However, the WPA was faster and had the advantage of detecting differences in reactions of yam genotypes to less aggressive pathogen isolates to which the ILA method showed no variation. A single disease evaluation at 7 days after inoculation was as good as the area under the disease progress curve (AUDPC) and the disease progress rate (Rd) derived from multiple evaluations. However, a significant time–genotype interaction, suggests a need for more than a single assessment for effective comparison of genotypes. AUDPC derived from two assessments (5 and 7 DAI) was better than AUDPC from three assessments (5, 7 and 9 DAI) in separating genotypes reactions to a less aggressive pathogen isolate. This study showed that the use of spray inoculation method, the WPA scoring method, and AUDPC derived from two assessments (5 and 7 DAI) provided best conditions for evaluating yam genotypes for levels of anthracnose resistance with the tissue culture‐derived whole plant assay.

Detection of the frequency, antimicrobial susceptibility, and genotypic discrimination of Aeromonas strains isolated from municipally treated tap water samples by cultivation and AP-PCR

The frequency, antibiotic susceptibility, and genotypic discrimination of Aeromonas strains isolated from municipally treated drinking tap water distribution systems were investigated in this study. We have analyzed 148 tap water samples collected from 8 different locations by bacterial cultivation and arbitrarily primed polymerase chain reaction (AP-PCR). Gram negative, hemolytic, oxidase (+) and catalase (+) bacterial colonies were applied to the study. Identification of bacterial colonies was done by conventional biochemical method and API ID 20E panel (BioMerieux-France). Molecular epidemiological discrimination of the isolates was done by AP-PCR. Aeromonas spp. was detected in 6 of 148 (4%) tap water samples from 8 different locations. Five isolates were identified as Aeromonas hydrophila and one isolate was identified as Vibrio fluvialis by conventional biochemical method. These data were also confirmed by API 20E panel. One of 6 isolates was resistant to gentamicin, 2 of 6 isolates were resistant to trimethoprim/sulfamethoxazole, 4 of 6 isolates were resistant to ampicillin and ampicillin-sulbactam and all of 6 isolates were resistant to cephalothin. All isolates were found to be susceptible to amikacin, aztreonam, ceftazidime, ceftriaxone, ciprofloxacin. All 6 strains of Aeromonas were discriminated by AP-PCR and were determined that all isolates were from different genotypic sources. Although the frequency of the isolates was under the standard limits, the results indicate that hemolytic A. hydrophila are present in municipally treated tap water samples in Mersin City. While all strains were genotypically distinct, all of them were resistant to first generation beta lactam antibiotics tested in this study.