Bacteriophage sensitivity patterns among bacteria isolated from marine waters

Phage-host cross-reaction tests were performed with 774 bacterial strains and 298 bacteriophages. The bacteria (bacteriophages) were isolated at different times from water samples collected in the Atlantic Ocean between the European continental shelf and the Sargasso Sea: 733 (258) strains; in the North Sea near Helgoland: 31 (31) strains; and in the Bay of Biscay: 10 (9) strains. Of the Atlantic Ocean bacteria 326 were found to be susceptible to one or more Atlantic Ocean bacteriophage(s). The bacteriophage sensitivity patterns of these bacteria vary considerably, placing 225 of them in two large clusters of bacteriophage-host systems. Taking all into account, 250 of the 326 Atlantic Ocean bacteria are different from each other. This high degree of variation among the bacteria distinguishes microbial populations derived from widely separated eastern and western regions of the Atlantic Ocean. It also sets apart from each other the populations derived from samples collected at successive stations some 200 miles apart, although to a lesser degree. With bacterial populations found from samples collected on the way back and forth between Europe and the Sargasso Sea a gradual change was observed from "western" phage sensitivity patterns to "eastern" ones. Sixty-nine Atlantic Ocean bacteria are sensitive to bacteriophages isolated from the North Sea and the Bay of Biscay; of these only 26 strains are also susceptible to Atlantic Ocean phages. The interpretation of the results is based on the hydrographical conditions prevailing in the northern Atlantic Ocean including the North Sea, and on the assumption that the microbial populations investigated have undergone genetic changes while being transported within water masses from west to east.     

New waterborne bacteriophages active on Yersinia enterocolitica.

Seven bacteriophages active on Yersinia enterocolitica (YE) were isolated from surface water samples collected in Granada, Spain. A comparison of the respective host ranges of these new phages and of reference phages used for YE phage typing showed that YE strains belonging to various phage types, grown at either 37 or 25 degrees C, expressed susceptibility to reference sewage water phages whereas susceptibility to new waterborne phages, as well as to reference phages from lysogenic YE, was only demonstrated in YE strains grown at 25 degrees C. A YE strain isolated by stool culture from a pig was lysogenic for a bacteriophage which behaved like waterborne phages and reference phages from lysogenic YE strains. The possibility that the isolation of waterborne bacteriophages might, in certain circumstances, reflect the presence of lysogenic YE was raised.     

Bacteriophages of methanotrophic bacteria

Bacteriophages of methanotrophic bacteria have been found in 16 out of 88 studied samples (underground waters, pond water, soil, gas and oil installation waters, fermentor cultural fluids, bacterial paste, and rumen of cattle) taken in different geographic zones of the Soviet Union. Altogether, 23 phage strains were isolated: 10 strains that specifically lysed only Methylosinus sporium strains, 2 strains that each lysed 1 of 5 Methylosinus trichosporium strains studied, and 11 strains that lysed Flavobacterium gasotypicum and, at the same time, 1 M. sporium strain. By fine structure, the phages were divided into two types (with very short or long noncontractile tails); by host range and serological properties, they fell into three types. One-step growth characteristics of the phages differed only slightly; the latent period varied from 6 to 8 h, the rise period varied from 4 to 6 h, and the average burst size was 100. All phages had guanine- and cytosine-rich double-stranded deoxyribonucleic acid consisting of common nitrogen bases. The molecular mass of the deoxyribonucleic acid as determined by restriction endonuclease analysis was 29.4 X 10(6) for M. sporium phages and 44 X 10(6) for F. gasotypicum phages. By all of the above-mentioned properties, all phages within each of the groups were completely identical to one another, but differed from phages of other groups. Bacteriophages lysing M. sporium and M. trichosporium GB2 were identical to phages M1 and M4, respectively, which were isolated earlier in the German Democratic Republic on the same methanotrophic species.     

Lytic and inhibition responses to bacteriophages among marine bacteria,with special reference to the origin of phage-host systems

The results of phage-host cross-reaction tests reported by Moebus & Nattkemper (1981) were re-examined using serially diluted bacteriophage suspensions to elicit the actual type of reaction between the bacteria and phage lysates tested. More than 1450 phage-host systems were studied at 25 °C incubation temperature. Among the nearly 300 phage strains used, 29 were identified as temperate ones. In about 65 % of the phage-host systems bacteriophage propagation was indicated by plaque formation. The remaining systems were characterized by the inhibition reaction of bacteria to phage lysates indicated by homogenously reduced bacterial growth within the test area without production of progeny phages. Since crude phage lysates had to be used, it remains obscure whether agents other than infective phage particles (defective ones or bacteriocins) caused this reaction. Among 269 systems of the inhibition type which were also tested at 5° and 15 °C, 54 were observed to propagate phages at one of or both the lower temperatures. Plaques produced at 15 °C with several phage-host systems were found to yield only few progeny phages which generally could not be propagated to produce high-titer phage stocks. With one system temperature-sensitive phage mutants were isolated. The probability of inhibition reactions occurring was found to be higher with phage-host systems isolated east of the Azores than with systems derived from the western Atlantic. With systems from the last mentioned area the proportion of inhibition versus lytic responses of bacteria to phages was observed to increase with the distance between the stations where both parts of the systems were derived. The latter findings are discussed in view of the assumption that bacterial and bacteriophage populations undergo genetic changes while being transported from west to east.     

Improved method for the isolation of Campylobacter jejuni and Campylobacter coli bacteriophages

A centrifugation and filtration method of isolating Campylobacter phages has been developed. Forty-nine Campylobacter phages were isolated from 272 effluent samples of which 42 produced lysis with Campylobacter jejuni strains and seven with C. coli strains. Phages were recovered from pig manure, abattoir effluents, human faeces, sewage and poultry manure. Phages were not isolated from water samples, cattle and sheep faeces or farm pasture soil.     

Bacteriophages Isolated in China for the Control of Pectobacterium carotovorum Causing Potato Soft Rot in Kenya

Soft rot is an economically significant disease in potato and one of the major threats to sustainable potato production. This study aimed at isolating lytic bacteriophages and evaluating methods for and the efficacy of applying phages to control potato soft rot caused by Pectobacterium carotovorum. Eleven bacteriophages isolated from soil and water samples collected in Wuhan, China, were used to infect P. carotovorum host strains isolated from potato tubers showing soft rot symptoms in Nakuru county, Kenya. The efficacy of the phages in controlling soft rot disease was evaluated by applying individual phage strains or a phage cocktail on potato slices and tubers at different time points before or after inoculation with a P. carotovorum strain. The phages could lyse 20 strains of P. carotovorum, but not Pseudomonas fluorescens control strains. Among the 11 phages, Pectobacterium phage Wc5 r, interestingly showed cross-activity against Pectobacterium atrosepticum and two phage-resistant P. carotovorum strains. Potato slice assays showed that the phage concentration and timing of application are crucial factors for effective soft rot control. Phage cocktail applied at a concentration of 1 9 109 plaque-forming units per milliliter before or within an hour after bacterial inoculation on potato slices, resulted in C 90%reduction of soft rot symptoms. This study provides a basis for the development and application of phages to reduce the impact of potato soft rot disease.     

Phage types of Staphylococcus aureus strains and their antibiotic resistance in carriers of medical students population

The phage types of 78 S. aureus strains isolated from nose swabs obtained from a medical students in 2005 -2006 was determined and antibiotic resistance of the phage types was analysed. 680 students were tested in order to obtain the strains and 11.5% of them were carriers of S. aureus. Phage typing was performed using basic set of23 phages and 3 additional phages: 88, 89 and 187. Drug resistance was determined by the disc-diffusion method. The most frequent in studied population were the group III (21.8%) and strains lysed by phages belonging to varied groups (21.8%). Highly different phage patterns were observed among strains belonging to each of the group. Strains belonging to the group III as the strains lysed by phages from varied groups were most frequently resistant only to penicillin (52,9% respectively). Resistance to penicillin was also most often observed in the strains belonging to another groups and phage types. Usefulness of the additional phages 88,89 and 187 was in the investigations as no more than 51% of strains was lysed by this phages.     

Distribution of RNA coliphages in Senegal, Ghana, and Madagascar

The distribution patterns of RNA coliphages (phages) in Senegal, Ghana, and Madagascar were investigated by collecting sewage samples from domestic drainage in November, 1980. In Senegal, among 65 sewage samples collected mainly from Dakar and its vicinity, 14 (22%) contained RNA phages (16 strains). By serological analysis, 13 of 16 strains were found to belong to group III. This is consistent with the distribution pattern of RNA coliphages in tropical and subtropical regions of Asia. In Ghana, however, among 106 samples collected from Accra, Suhum, and their vicinities, only seven (7%) contained RNA phages (seven strains) (groups I, II, and III [1:3:3]). In Madagascar, among 124 samples collected from Antananarivo, Moramanga, and their vicinities, seven (6%) contained RNA phages (seven strains) (groups I, II, III, and IV [1:1:1:4]). In spite of the low isolation frequency, it can be said that Madagascar appears to have a unique distribution pattern (abundance of group IV phages) which differs from that of any other countries we have examined. The generality of the distribution pattern of RNA phages in the tropical region (abundance of group III phages) was thus verified at least in Senegal.     

Homogeneity of the morphological groups of bacteriophages infecting Bacteroides fragilis strain HSP40 and strain RYC2056

Bacteriophages infecting Bacteroides fragilis strains RYC2056 and HSP40 have been proposed as indicators of water quality. To accomplish this function, homogeneity of the group of phages detected by these strains is necessary to ensure that the final results are not due to the different kinetics of inactivation of the phages. To evaluate homogeneity, we observed by electron microscopy bacteriophages isolated from sewage with two Bacteroides fragilis strains (HSP40 and RYC2056). A predominant group of phages was observed, Siphoviridae with slightly curved tails. Detection of other minority groups, which could be present in the sample, was done with neutralization experiments by using antiserum against the majority group and with host mutants resistant to infection with the predominant phage. Although two other minority groups were observed, results showed that bacteriophages infecting B. fragilis strain HSP40 and strain RYC2056 form a homogeneous group, Siphoviridae with slightly curved tails being the most predominant in sewage.     

Bacterial host strains that support replication of somatic coliphages

Somatic coliphages detected by Escherichia coli strain WG5 have been proposed as potential indicators of water quality. Their potential replication in the water environment is considered a drawback for their use as indicators. However, the contribution of replication outside the gut to the total numbers has never been quantified. It has not been determined either the fraction of bacterial strains that might support replication of phages detected by strain WG5 in the water environment. We examined the sensitivity of 291 host strains to 25 phages by streaking slants of the presumptive host strain onto an agar layer that contains bacteriophages, which gives a total of 7275 combinations (sensitivity tests). Only a 3.02% of the tests showed sensitivity. Additionally, six environmental strains were used as hosts to count phages in sewage and seawater. Phages isolated on these strains were used to infect strain WG5. The environmental strains detected 1 log₁₀ fewer phages than strain WG5 in sewage and seawater. The fraction of phages that were detected by the six strains and that also infected strain WG5 ranged from < 0.07% to < 2.0% of the total amount of bacteriophages detected by strain WG5 in the same samples. Our results confirm that less than 3% of naturally occurring hosts support replication of phages infecting E. coli. We conclude that the contribution of replication to the number of somatic coliphages detected in the aquatic environment is negligible. This revised version was published online in June 2006 with corrections to the Cover Date.     

Bacteriophages of Erwinia amylovora

Fifty bacteriophage isolates of Erwinia amylovora, the causal agent of fire blight, were collected from sites in and around the Niagara region of southern Ontario and the Royal Botanical Gardens, Hamilton, Ontario. Forty-two phages survived the isolation, purification, and storage processes. The majority of the phages in the collection were isolated from the soil surrounding trees exhibiting fire blight symptoms. Only five phages were isolated from infected aerial tissue in pear and apple orchards. To avoid any single-host selection bias, six bacterial host strains were used in the initial isolation and enrichment processes. Molecular characterization of the phages with a combination of PCR and restriction endonuclease digestions showed that six distinct phage types, described as groups 1 to 6, were recovered. Ten phage isolates were related to the previously characterized E. amylovora PEa1, with some divergence of molecular markers between phages isolated from different sites. A study of the host ranges of the phages revealed that certain types were unable to efficiently lyse some E. amylovora strains and that some isolates were able to lyse the epiphytic bacterium Pantoea agglomerans. Representatives from the six molecular groups were studied by electron microscopy to determine their morphology. The phages exhibited distinct morphologies when examined by an electron microscope. Group 1 and 2 phages were tailed and contractile, and phages belonging to groups 3 to 6 had short tails or openings with thin appendages. Based on morphotypes, the bacteriophages of E. amylovora were placed in the order Caudovirales, in the families Myoviridae and PODOVIRIDAE:     

Host ranges of Listeria-specific bacteriophages from the turkey processing plant environment in the United States

Even though at least 400 Listeria phages have been isolated from various sources, limited information is available on phages from the food processing plant environment. Phages in the processing plant environment may play critical roles in determining the Listeria population that becomes established in the plant. In this study, we pursued the isolation of Listeria-specific phages from environmental samples from four turkey processing plants in the United States. These environmental samples were also utilized to isolate Listeria spp. Twelve phages were isolated and classified into three groups in terms of their host range. Of these, nine (group 1) showed a wide host range, including multiple serotypes of Listeria monocytogenes, as well as other Listeria spp. (L. innocua, L. welshimeri, L. seeligeri, and L. ivanovii). The remaining phages mostly infected L. monocytogenes serotype 4b as well as L. innocua, L. ivanovii, and/or L. welshimeri. All but one of the strains of the serotype 4b complex (4b, 4d, 4e) from the processing plant environment could be readily infected by the wide-host-range phages isolated from the environment of the processing plants. However, many strains of other serotypes (1/2a [or 3a] and 1/2b [or 3b]), which represented the majority of L. monocytogenes strains isolated from the environmental samples, were resistant to infection by these phages. Experiments with two phage-resistant strains showed reduced phage adsorption onto the host cells. These findings suggest that phage resistance may be an important component of the ecology of L. monocytogenes in the turkey processing plants.     

Homogeneity of the Morphological Groups of Bacteriophages Infecting <Emphasis Type="Italic">Bacteroides fragilis</Emphasis> Strain HSP40 and Strain RYC2056

Bacteriophages infecting Bacteroides fragilis strains RYC2056 and HSP40 have been proposed as indicators of water quality. To accomplish this function, homogeneity of the group of phages detected by these strains is necessary to ensure that the final results are not due to the different kinetics of inactivation of the phages. To evaluate homogeneity, we observed by electron microscopy bacteriophages isolated from sewage with two Bacteroides fragilis strains (HSP40 and RYC2056). A predominant group of phages was observed, Siphoviridae with slightly curved tails. Detection of other minority groups, which could be present in the sample, was done with neutralization experiments by using antiserum against the majority group and with host mutants resistant to infection with the predominant phage. Although two other minority groups were observed, results showed that bacteriophages infecting B. fragilis strain HSP40 and strain RYC2056 form a homogeneous group, Siphoviridae with slightly curved tails being the most predominant in sewage. Received: 7 March 2002 / Accepted: 5 August 2002     

Microsatellite Variation in Populations of Atlantic Salmon from North Europe

Our aim was to investigate the level of genetic differentiation in northern European populations of Atlantic salmon, to establish the genetic relationship among major salmon populations in Russia and North Norway, and to compare these to populations from the western Atlantic lineage. Samples were collected along an east—west axis, from Pechora River in Russia to Restigouche River in Quebec, Canada. A total of 439 individual salmon were collected from seven rivers (sample sizes from 50 to 84 individuals). The samples were analysed for variation at four microsatellite loci; Ssa13.37, Ssa14, Ssa171 and Ssa171. Significant differences were found between most of the European populations, and the populations from the Tana and Pechora Rivers were most distinct. The samples from the Rivers Mezenskaya Pizhma and Emtsa in Arkhangelsk oblast in Russia were not significantly different from each other in an exact test of population differences. All other river pairs were significantly different. These results confirmed the deep genetic divergence between American and European salmon populations demonstrated in earlier studies, with alleles specific to continent found in three of the microsatellites.     

Isolation of Escherichia coli bacteriophages from the stool of pediatric diarrhea patients in Bangladesh

A 3-week coliphage survey was conducted in stool samples from 140 Bangladeshi children hospitalized with severe diarrhea. On the Escherichia coli indicator strain K803, all but one phage isolate had 170-kb genomes and the morphology of T4 phage. In spot tests, the individual T4-like phages infected up to 27 out of 40 diarrhea-associated E. coli, representing 22 O serotypes and various virulence factors; only five of them were not infected by any of these new phages. A combination of diagnostic PCR based on g32 (DNA binding) and g23 (major capsid protein) and Southern hybridization revealed that half were T-even phages sensu strictu, while the other half were pseudo-T-even or even more distantly related T4-like phages that failed to cross-hybridize with T4 or between each other. Nineteen percent of the acute stool samples yielded T4-like phages, and the prevalence was lower in convalescent stool samples. T4-like phages were also isolated from environmental and sewage water, but with low frequency and low titers. On the enteropathogenic E. coli strain O127:K63, 14% of the patients yielded phage, all of which were members of the phage family Siphoviridae with 50-kb genomes, showing the morphology of Jersey- and beta-4 like phages and narrow lytic patterns on E. coli O serotypes. Three siphovirus types could be differentiated by lack of cross-hybridization. Only a few stool samples were positive on both indicator strains. Phages with closely related restriction patterns and, in the case of T4-like phages, identical g23 gene sequences were isolated from different patients, suggesting epidemiological links between the patients.     

Biodiversity of Lactococcus lactis bacteriophages in Polish dairy environment

We present here the results of an exploration of the bacteriophage content of dairy wheys collected from milk plants localized in various regions of Poland. Thirty-three whey samples from 17 regions were analyzed and found to contain phages active against L. lactis strains. High phage titer in all whey samples suggested phage-induced lysis to be the main cause of fermentation failures. In total, over 220 isolated phages were examined for their restriction patterns, genome sizes, genetic groups of DNA homology, and host ranges. Based on DNA digestions the identified phages were classified into 34 distinct DNA restriction groups. Phage genome sizes were estimated at 14-35 kb. Multiplex PCR analysis established that the studied phages belong to two out of the three main lactococcal phage types--c2 and 936, while P335-type phages were not detected. Yet, analyses of bacterial starter strains revealed that the majority of them are lysogenic and carry prophages of P335-type in their chromosome. Phage geographical distribution and host range are additionally discussed.     

A sub-division ofSalmonella typhimurium into phage types based on the method of craigie and yen; Phages adaptable to species of the B and D group ofSalmonella; Phase adsorption as diagnostic aid

Summary and conclusions Phages were isolated which were adsorbed bySalmonella strains of groups B and D. These phages were adaptable to strains of species from these groups. The behaviour of some adaptations of these phages on strains ofS. paratyphi B has been described. A typing scheme forS. typhimurium has been established. So far, this consists of 32 types which have all been demonstrated with adaptations of a single phage.     

Differentiation of methicillin-resistant strains of Staphylococcus aureus by prophage specificity]

By inducing with mitomycin C the following phages were isolated from all the tested 32 methicillin resistant strains of S. aureus: the serogroup B phage was isolated from 2 strains, the serogroup B and F phages were isolated from 5 strains and the serogroup F phage was isolated from 25 strains. The phages were divided into 5 groups by the antiphage immunity. In group 1 of the phages 4 additional phages were specified. By the specificity of the prophages in the cultures all the strains were divided into 5 groups. Group 1 of the cultures was divided into 5 subgroups (A, B, C, D and E).     

Bacteriophages of Erwinia amylovora

Fifty bacteriophage isolates of Erwinia amylovora, the causal agent of fire blight, were collected from sites in and around the Niagara region of southern Ontario and the Royal Botanical Gardens, Hamilton, Ontario. Forty-two phages survived the isolation, purification, and storage processes. The majority of the phages in the collection were isolated from the soil surrounding trees exhibiting fire blight symptoms. Only five phages were isolated from infected aerial tissue in pear and apple orchards. To avoid any single-host selection bias, six bacterial host strains were used in the initial isolation and enrichment processes. Molecular characterization of the phages with a combination of PCR and restriction endonuclease digestions showed that six distinct phage types, described as groups 1 to 6, were recovered. Ten phage isolates were related to the previously characterized E. amylovora PEa1, with some divergence of molecular markers between phages isolated from different sites. A study of the host ranges of the phages revealed that certain types were unable to efficiently lyse some E. amylovora strains and that some isolates were able to lyse the epiphytic bacterium Pantoea agglomerans. Representatives from the six molecular groups were studied by electron microscopy to determine their morphology. The phages exhibited distinct morphologies when examined by an electron microscope. Group 1 and 2 phages were tailed and contractile, and phages belonging to groups 3 to 6 had short tails or openings with thin appendages. Based on morphotypes, the bacteriophages of E. amylovora were placed in the order Caudovirales, in the families Myoviridae and Podoviridae.