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Isolation and characterization of two anti-staphylococcal bacteriophages specific for pathogenic Staphylococcus aureus associated with bovine infections.

AIMS: The aim of this study was to isolate and characterize bacteriophages against bovine Staphylococcus aureus associated with mastitis. METHODS AND RESULTS: We describe the isolation of two anti-staphylococcal phages namely DW2 and CS1 from farmyard slurry. Both phages were characterized by electron microscopy and restriction analysis and shown to belong to the Siphoviridae family. CS1 and DW2 were lytic for representatives of all three clonal groups of Irish mastitis-associated staphylococci. These phages were compared with the previously characterized Myoviridae phage K. Infusion of a cocktail of all three phages at 10(8) PFU ml(-1) into live cow teats resulted in no detectable increase in somatic cell counts in milks indicating that the phages did not irritate the animal. CONCLUSION: Two new anti-staphylococcal phages CS1 and DW2 were isolated and characterized and tested for immunogenicity in animal teats. SIGNIFICANCE AND IMPACT OF THE STUDY: The phages isolated in this study are active against pathogenic S. aureus and may be incorporated into teat-dips or teat-washes as a non-antibiotic prophylaxis against staphylococcal bovine mastitis.

Animals↗

Nasal and cutaneous flora among hemodialysis patients and personnel: quantitative and qualitative characterization and patterns of Staphylococcal carriage.

Staphylococcal sepsis is a leading cause of morbidity and mortality among chronic hemodialysis (HD) patients. We studied nasal and cutaneous flora of HD patients and personnel and their patterns of staphylococcal carriage. HD patients had significantly increased cutaneous total bacterial colony counts (p less than 0.01) as well as both nasal (p less than 0.0001) and cutaneous (p less than 0.0001) carriage of Staphylococcus aureus compared to personnel. Cutaneous staphylococcal carriage could be significantly correlated with nasal carriage (p less than 0.01). Cutaneous streptococcal species and gram-negative bacilli were not different between patients and personnel. Staphylococcal phage typing of nasal isolates from staphylococcal carriers revealed a mean of 90% of isolates from each subject belonging to a predominant phage type. Predominant nasal staphylococcal phage types corresponded with respective predominant cutaneous phage types in 93% of HD patients carriers. These studies substantiate autoinoculation of S. aureus from the nasal vestibule to the skin overlying the vascular access site.

Adolescent↗

Experiences and observations with the typing of Staphylococcus aureus phage 94.

During a 28-month period, 5,078 cultures from a variety of anatomical sites were received for staphylococcal phage typing. Of these, 503 (10%) were not suitable for the procedure requested. Of the 4,575 viable cultures, 1,030 (23%) of the microorganisms were nontypable at both the routine test dilution (RTD) and at 100 times RTD. Of the 3,545 typable organisms, 3,061 (86%) were lysed at RTD, whereas 484 (14%) were typed only at 100 times RTD. Observations pertaining to the typing efficacy of staphylococcal phage 94 indicate that 651 (18%) of the typable microorganisms were lysed only by phage 94 at RTD or at 100 times RTD. Without the addition of this new phage to the international basic set, the number of nontypable strains (1,030 or 23%) would have been 1,681 (39%). Data regarding the geographic distribution of Staphylococcus aureus phage 94 point to the occurrence of the host strain in 13 (68%) of 19 states and 18 (62%) of the 29 hospitals submitting specimens to this laboratory. The assumed origin and speculated mode of dissemination of this microorganism are discussed.

Aerospace Medicine↗

Molecular genetics of SaPI1--a mobile pathogenicity island in Staphylococcus aureus.

The Staphylococcus aureus gene for toxic shock toxin (tst) is carried by a 15 kb mobile pathogenicity island, SaPI1, that has an intimate relationship with temperate staphylococcal phage 80alpha. During phage growth, SaPI1 is excised from its unique chromosomal site, attC, replicates autonomously, interferes with phage growth, and is efficiently encapsidated into special small phage heads commensurate with its size. Upon transfer to a recipient organism, SaPI1 integrates at attC by means of a self-coded integrase. One or more phage functions are required for excision, autonomous replication and encapsidation of the element and, thus, the overall relationship between SaPI1 and 80alpha is similar to that between coliphages P4 and P2. Among other staphylococcal phages tested, only phi13 interacts with SaPI1, inducing excision but not replication or transfer of the element.

Attachment Sites, Microbiological↗

Treatment of experimental infections of mice with bacteriophages.

Bacteriophages for Acinetobacter baumanii, Pseudomonas aeruginosa and Staphylococcus aureus were tested in experimental infections of mice to investigate their potential for the treatment of infections of man. As few as 10(2) particles of an acinetobacter phage protected mice against 5 LD50 (1 x 10(8)) of a virulent strain of A. baumanii, and phage was demonstrated to have multiplied in the mice. A pseudomonas phage protected mice against 5 LD50 of a virulent strain of P. aeruginosa, with a PD50 of 1.2 x 10(7) particles. A staphylococcal phage failed to protect mice infected with a strain of S. aureus. These studies support the view that bacteriophages could be useful in the treatment of human infections caused by antibiotic-resistant strains of bacteria.

Acinetobacter Infections↗

Effect of protein A on adsorption of bacteriophages to Staphylococcus aureus.

Experiments were performed to determine if protein A influenced the association of bacteriophages with Staphylococcus aureus. Bacteriophage adsorption was compared in a S. aureus strain rich in protein A and mutants of this strain with very little protein A, in a strain with little protein A, and in mutants of this strain with increased protein A. In addition, the effect of growth in mannitol-salt broth and trypsin digestion (known to reduce protein A) on bacteriophage absorption was measured. There was an inverse relationship between protein A content of strains and the quantity of bacteriophage absorbed. However, no inhibition of staphylococcal phages was obtained with purified soluble protein A. Protein A as a surface component rendered the bacteria more resistant to adsorption of staphylococcal typing phages presumably by masking the phage receptor sites. When protein A-deficient mutants were incubated with bacteriophages, there was survival of staphylococci with increased protein A content probably due to a selective action.

Adsorption↗

INHIBITORY ACTION OF PHAGE K ON STAPHYLOCOCCAL DEHYDROGENASES. I. EFFECT ON VARIOUS STRAINS OF STAPHYLOCOCCUS AUREUS, INCLUDING MEMBERS OF THE PHAGE-TYPING SERIES.

Ralston, D. J. (University of California, Berkeley) and B. S. Baer. Inhibitory action of phage K on staphylococcal dehydrogenases. I. Effect on various strains of Staphylococcus aureus, including members of the phage-typing series. J. Bacteriol. 86:666-672. 1963.-The polyvalent phage K was found to depress the dehydrogenase activities of a large number of Staphylococcus aureus strains, as measured by the reduction of triphenyl tetrazolium chloride to the insoluble red formazan. The inhibition occurred immediately after the absorption of a multiplicity of phage particles, and was independent of the infectibility of the strains and of the killing ability of the phage. It appeared to be closely associated with the phenomenon of sensitization-a change in the cell surface which increased the susceptibility of the wall to digestion by soluble staphylococcal lysins and simultaneously abolished the capacity to synthesize phage. The inhibitory effect occurred both in nutrient media and in a nongrowth glucose - phosphate buffer supplemented with cysteine.

Bacteriophage Typing↗