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PubMed1985

Bacteriophage typing of Staphylococcus aureus strains isolated from Bloemfontein dairy herds.

Bacteriophage typing was performed on 88 coagulase positive Staphylococcus aureus strains isolated during a survey of subclinical mastitis in Bloemfontein dairy herds. Phage typing was performed using two basic international phage typing sets, i.e. the human isolate phage set (HPS) and the bovine isolate phage set (BPS). The results clearly indicated that the BPS could be successfully applied for the phage typing of bovine mastitis S. aureus strains. The majority of the strains was typed as BPS phage group IV (78,4%) and HPS group III (47,7%). The high prevalence of BPS group IV strains is in agreement with other studies. The prevalence of non-typable strains was 3,4% for BPS and 28,4% for HPS. Phages 102, 117, 107, 81, 47, and 6 had high lytic activity. BPS group IV patterns (102/107/117 and 102/117) dominated. The incidence of unique phage patterns was 12,5% for BPS and 26,0% for HPS. A relatively high proportion (71,3%) of the strains was typable with the HPS. As these strains were of possible human origin it indicated the possibility of mutual human-animal transfer of the pathogens. No relationship could be found between phage groups on the one hand and multiple antibiotic resistance on the other, and no phage groups dominated within herds.

Animals↗
PubMed1998

Characterization of a gene encoding a single-subunit bacteriophage-type RNA polymerase from maize which is alternatively spliced.

Single-subunit RNA polymerases belonging to the T3/T7 bacteriophage family are thought to be common throughout eukaryotes. We report the isolation and characterization of a nucleus-encoded single-subunit RNA polymerase gene from maize. This gene is highly homologous to other single-subunit RNA polymerase genes from Arabidopsis, Chenopodium. yeast and Neurospora crassa involved in organellar transcription. Genomic Southern analysis reveals 10 to 15 hybridising fragments, suggesting that maize contains a small gene family. The isolated gene contains 19 exons and its genomic structure is highly conserved when compared to the three Arabidopsis homologues. Unlike the case in Arabidopsis, intron-12 of the maize bacteriophage-type RNA polymerase gene is alternatively spliced. Quantitative RT-PCR revealed that the resultant alternatively spliced transcript represents approximately 21 to 26% of the total polymerase mRNA in maize coleoptiles. The orthologous wheat bacteriophage-type RNA polymerase is also alternatively spliced and the intron exhibits 78% identity to maize intron-12. The conservation in alternative splicing between wheat and maize and its absence from Arabidopsis suggest a functional requirement for the alternatively spliced product.

Alternative Splicing↗
PubMed1998

Combined use of bacteriophage typing and pulsed-field gel electrophoresis in the epidemiological analysis of Japanese isolates of enterohemorrhagic Escherichia coli O157:H7.

A total of 236 enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates in Japan were investigated by bacteriophage typing, and the results were compared with those of pulsed-field gel electrophoresis (PFGE). Seven phage types (PTs) were observed in 71 isolates which were derived from 22 outbreaks. All of the isolates from ten outbreaks in the Kinki region (midwestern part of Japan) in July-August 1996 were grouped into the same PFGE type (IIa) and PT 32, while among total isolates, there were such varieties as PFGE type IIa containing five phage types and PT32 containing two PFGE types. These results suggest that the ten outbreaks should be considered to be a single outbreak, and show that the combined use of bacteriophage typing and PFGE enhances reliability in epidemiological surveys.

Bacteremia↗
PubMed1996

Molecular epidemiology of Escherichia coli O157:H7 by pulsed-field gel electrophoresis and comparison with that by bacteriophage typing.

One hundred twenty-four Escherichia coli O157:H7 isolates were characterized by pulse-field gel electrophoresis, bacteriophage typing, and PCR of verotoxin genes. Diversity indices obtained--0.786 for phage types and 0.987 for pulsed-field gel electrophoresis types--demonstrated that phage typing falls below the critical value (0.9) required for confident interpretation of results.

Animals↗
PubMed1987

New bacteriophage typing scheme for subdivision of the frequent capsular serotypes of Klebsiella spp.

A bacteriophage typing scheme for hospital isolates of Klebsiella spp. was developed. The scheme was designed specifically as a secondary typing method to discriminate between strains of serotypes K2, K3, and K21 but proved to be an efficient general typing method for strains of most serotypes. The set of 15 phages gave 87.3% typeability on 236 strains of more than 70 different serotypes. Typeability within the K2, K3, and K21 strains was 93, 89, and 91%, respectively. There was a mean of 3.2 reactions strain-1 for all phage-typeable strains. Of the serologically nontypeable strains, 76.7% were susceptible to one or more phages. The most common pattern accounted for only 7% of the strains. The lytic patterns were reproducible if strains were typed on the same day, but differences were observed if strains were stored for 1 week or more before retyping. A total of 96.5% of the strains were typeable by a combination of capsular serology and phage typing.

Bacteriophage Typing↗
PubMed1978

Comparison of bacteriophage typing, serotyping, and biotyping as aids in epidemiological surveillance of Klebsiella infections.

Bacteriophage typing was used to subdivide Klebsiella obtained from patients in a surgical intensive care unit during a 2-year period. The 15 phages employed to type the strains were propagated by a soft-agar layer technique. In all, 23 phage types were found among the 120 clinical strains. The phage types of repeat isolates were reproducible. Only 70% of the strains tested were phage typable, but when used in conjunction with capsular serotyping and biotyping, a much greater subdivision of the Klebsiella strains was achieved. The addition of phage typing to serobiotyping for epidemiological analysis suggested that the number of cross-infecting Klebsiella strains in the intensive care unit was few, but that these strains persisted in the unit for long periods of time and could infect different body sites.

Bacteriophage Typing↗
PubMed1977

Comparison of strains of Mycobacterium tuberculosis from British, Ugandan and Asian immigrant patients: a study in bacteriophage typing, susceptibility to hydrogen peroxide and sensitivity to thiophen-2-carbonic acid hydrazide.

Strains of Mycobacterium tuberculosis were obtained from 65 patients with pulmonary tuberculosis resident in Uganda, and from pulmonary and extrapulmonary tuberculosis in 42 British patients of European ethnic stock and in 67 Asian immigrants, often from Uganda, resident in Britain. The bacteriophage-type patterns of the African, British and Asian strains were different. The pattern for the Asian strains resembled that found previously in patients from South India, suggesting that there has been little interchange of organisms between the Asian community and the African and British communities alongside whom they have lived. The patterns for pulmonary and extra-pulmonary tuberculosis were similar. Strains of bacteriophage type 1, mainly obtained from Asians, were characterized by a greater susceptibility to the bactericidal activity of hydrogen-peroxide and/or a greater sensitivity to thiophen-2-carbonic acid hydrazide than strains of other types.

Asia↗
PubMed1988

Bacteriophage typing of Mycobacterium tuberculosis cultures from incidents of suspected laboratory cross-contamination.

Bacteriophage typing was performed on 235 Mycobacterium tuberculosis cultures submitted from 31 laboratories. In each instance, either the attending physician questioned the misdiagnosis of tuberculosis or the laboratory supervisor suspected that laboratory cross-contamination had occurred. Phage typing data confirmed these suspicions. Phage typing is a useful adjunct in the investigation of suspected cross-contamination of laboratory cultures of M. tuberculosis.

Bacteriophage Typing↗
PubMed1961

METABOLIC CHARACTERIZATION OF THE GENUS BRUCELLA IV. 3: Correlation of Oxidative Metabolic Patterns and Susceptibility to Brucella Bacteriophage, Type abortus, Strain.

Meyer, Margaret E. (University of California, Davis). Metabolic characterization of the genus Brucella. IV. Correlation of oxidative metabolic patterns and susceptibility to Brucella bacteriophage, type abortus, strain 3. J. Bacteriol. 82:950-953. 1961.-A total of 212 strains of brucellae that had been identified as Brucella melitensis, B. abortus, B. suis, or B. neotomae by their oxidative metabolism were tested for their susceptibility to Brucella bacteriophage, type abortus, strain 3. It was demonstrated that only those organisms that displayed the oxidative metabolic pattern that is singular for B. abortus were susceptible to this strain of phage, irrespective of their identity by the conventional methods usually employed for differentiating members of this genus. Strains of organisms that display the features of B. melitensis by the conventional determinative methods, but display the metabolic characteristics of B. abortus, are susceptible to lysis by this phage. These organisms are in fact B. abortus. Strains of organisms that display the features of B. melitensis by the classical methods, and display the metabolic pattern of B. melitensis, are not lysed by this phage. These organisms are B. melitensis. The conclusions then were drawn that B. abortus is the only species that can serve as host for this strain of phage, that oxidative metabolic patterns accurately identify the species in this genus, and that by the conventional methods of differentiation, many strains of B. abortus are misidentified as B. melitensis.

Journal Article↗
PubMed1994

Bacteriophage typing in Salmonella bareilly.

A total of 675 strains of Salmonella bareilly received from different parts of India and France during 1959-92 were phage typed using six bacteriophages. Overall typability achieved was 90.8% with 23 distinct phage types excluding a group of untypable strains. Phage types have been defined in octal code. Simpson's coefficient was applied for diversity index having a value of 0.839. This system was found to be reproducible, stable and epidemiologically useful.

Animals↗
PubMed1978

Modification of methods used in bacteriophage typing of Mycobacterium tuberculosis isolates.

A procedure in which soft agar overlays were used in bacteriophage-typing Mycobacterium tuberculosis is presented. This safer method uses commercially available media, whereas media presently used must be prepared in the laboratory. Single plaque isolations of the phage BG-1 specifying phage type A and B of M. tuberculosis were readily made by using the modified procedures. This purification and the use of prototype strain Myc 1415 as the indicator host strain have significantly enhanced the ability to discriminate among strains of phage types A and B.

Bacteriophage Typing↗
PubMed2003

Analysis of molecular epidemiology of Chilean Salmonella enterica serotype enteritidis isolates by pulsed-field gel electrophoresis and bacteriophage typing.

Human Salmonella enterica serotype Enteritidis infections emerged in Chile in 1994. S. enterica serotype Enteritidis phage type 1 isolates predominated in the north, and phage type 4 isolates predominated in the central and southern regions. A study was planned to characterize this epidemic using the best discriminatory typing technique. Research involved 441 S. enterica serotype Enteritidis isolates, including clinical preepidemic samples (n = 74; 1975 to 1993) and epidemic (n = 199), food (n = 72), poultry (n = 57), and some Latin American (n = 39) isolates. The best method was selected based on a sample of preepidemic isolates, analyzing the discriminatory power (DP) obtained by phage typing and randomly amplified polymorphic DNA and pulsed-field gel electophoresis (PFGE) analysis. The highest DP was associated with BlnI PFGE-bacteriophage typing analysis (0.993). A total of 38 BlnI patterns (B patterns) were identified before the epidemic period, 19 since 1994, and only 4 in both periods. Two major clusters were identified by phylogenetic analysis, and the predominant B patterns clustered in the same branch. Combined analysis revealed that specific B pattern-phage type combinations (subtypes) disappeared before 1994, that different genotypes associated with S. enterica serotype Enteritidis phage type 4 had been observed since 1988, and that strain diversity increased before the expansion of S. enterica serotype Enteritidis in 1994. Predominant subtype B3-phage type 4 was associated with the central and southern regions, and subtype B38-phage type 1 was associated with the north (P < 0.0001). Food and poultry isolates matched the predominant S. enterica serotype Enteritidis subtypes, but isolates identified in neighboring countries (Peru and Bolivia) did not match S. enterica serotype Enteritidis subtypes identified in the north of Chile. The results of this work demonstrate that genetic diversity, replacement, and expansion of specific S. enterica serotype Enteritidis subtypes were associated with epidemic changes.

Animals↗
PubMed1988

Immunoblots, antimicrobial resistance, and bacteriophage typing of oxacillin-resistant Staphylococcus aureus.

An immunoblotting system was developed for typing of oxacillin-resistant Staphylococcus aureus. Clinical isolates recovered during a 40-month period at a single institution were evaluated with this typing scheme. Results were compared with susceptibility patterns and with bacteriophage typing results for 100 clinical isolates and with plasmid fingerprints for 14 isolates. Immunoblotting was found to be a useful method with good reproducibility that distinguished seven major groups of patient isolates that were clinically and epidemiologically related. Susceptibility patterns showed specific correlations with other typing results but were inferior to immunoblotting and phage typing for differentiating major groups of organisms. Plasmid profiles failed to distinguish two major groups that were readily identified by immunoblots and phage typing. There was evidence of increasing antimicrobial resistance of endemic hospital strains. Immunoblotting correlated well with phage typing, offered an alternative method for typing isolates that could not be typed by phage typing, and was superior to susceptibility testing and plasmid profiles for distinguishing different groups of oxacillin-resistant S. aureus at our institution.

Bacteriophage Typing↗
PubMed1965

RAPID METHOD OF DETERMINING COAGULASE ACTIVITY DURING STAPHYLOCOCCAL BACTERIOPHAGE TYPING.

The plate test, a modification of the slide test described by Cadness-Graves was developed for the rapid identification of coagulase-positive staphylococci in conjunction with bacteriophage typing. An evaluation of 1,145 cultures by three coagulase-determination methods, the slide, tube, and plate tests, indicates that the plate test is as accurate as the slide tests, and the plate test agrees 97.7% with the tube test.

Bacteriophage Typing↗