Changes in typing pattern of phage-type 80 staphylococci

Distribution of Phage Groups of Staphylococcus aureus in the Years 1927 through 1947

The phage typing patterns of 194 typable strains of Staphylococcus aureus isolated in the years 1927 through 1947 and preserved as stock cultures revealed that 43 strains were of phage type 80/81. The occurrence of other typable strains in the broad phage groups I, II, and III corresponded closely to the frequency distribution of staphylococci reported in 1945 by Wilson and Atkinson.

Characterization of erythromycin-resistant isolates of Staphylococcus aureus recovered in the United States from 1958 through 1969

We tested 16 erythromycin-resistant clinical isolates of S. aureus, recovered from patients hospitalized in the United States from 1958 to 1969, for the presence of ermA, ermB, and ermC by using PCR. Fifteen of 16 isolates contained at least one copy of ermA; the remaining isolate, which was also clindamycin resistant, contained ermB. Eight of the 15 isolates harboring ermA, all of which were inducible, contained a single copy of the gene in the chromosome, while the remaining seven isolates had two copies of the gene. ermB was plasmid encoded and mediated constitutive resistance to erythromycin.

Lysogeny in staphylococci

Blair, John E. (Hospital for Joint Diseases, New York, N. Y.) and Miriam Carr. Lysogeny in staphylococci. J. Bacteriol. 82:984-993. 1961.-Changes in the phage typing patterns of strains of staphylococci of the 80/81-52/52A/80/81 complex and of phage group III were produced by lysogenization with temperate phages derived from selected strains of Staphylococcus aureus. The phages used were of the serological groups A, B, and F. Certain changes of phage pattern were related to serologically specific prophage immunity; others were nonspecific, or resulted from the conversion of a strain from partial resistance to full sensitivity to certain typing phages. In addition to an alteration of their phage typing pattern, the lysogenization of certain strains by appropriate phages effected a reversal of their susceptibility to penicillin. The capacity to produce toxin was conferred upon certain nontoxigenic strains by lysogenization with a phage derived from a toxigenic strain.

THE EVOLUTION OF NEW HOSPITAL STRAINS OF STAPHYLOCOCCUS AUREUS

The emergence of new groups of strains of Staph. aureus as important causes of endemic hospital infection in Great Britain has been followed by the phage typing method. Experiments are reported which suggest the possible origin of one of them.

Labile antibiotic resistance in Staphylococcus aureus

Twenty-two isolates of Staphylococcus aureus, recovered from patients over a period of about one year, exhibited low level resistance to mupirocin, developed a salmon pink colour on culture and 21 had the same phage-type. However the plasmid profiles and associated antibiotic resistances differed. Digestion of cellular DNA with SmaI showed that two isolates from a single patient had a markedly different pattern to the remainder, and that six others differed by one band, though these formed groups of one and five isolates. This episode apparently represents a small outbreak of colonization or infection, which would have been missed but for the unusual pigmentation of the isolates recovered, and illustrates the difficulties of relying on a single typing system.

Pulsed-field gel electrophoresis as a replacement for bacteriophage typing of Staphylococcus aureus

Bacteriophage typing (BT) (World Health Organization method) has been used at the Centers for Disease Control and Prevention for over 30 years to type isolates of Staphylococcus aureus. Since studies have shown that BT patterns have poor reproducibility and because BT fails to type a high percentage (15 to 20%) of isolates, the Centers for Disease Control and Prevention has converted from using BT to using pulsed-field gel electrophoresis (PFGE) for strain typing S. aureus. We compared the results of BT with results of PFGE for typing 300 isolates of S. aureus, including strains from several well-characterized outbreaks. Ninety-six isolates were BT group I, 19 were group II, 82 were group III, 7 were group V, and 96 were nontypeable. PFGE identified subgroups within each phage group and thus was more discriminating than BT, which identified no subgroups. PFGE was able to type all isolates and distinguish related from unrelated strains of S. aureus. Our modified, standardized PFGE methodology should enable typing laboratories to obtain rapid, reliable results in 3 to 4 days when starting with an isolated colony on agar media.

Mupirocin-resistant Staphylococcus aureus in a specialist school population

Staphylococcus aureus strains resistant to mupirocin (MIC > 4000 mg l-1) were recovered from children and staff at a school for children with eczema and/or asthma or cystic fibrosis after mupirocin had been used to treat eczematous lesions. At least three distinct strains of S. aureus were involved and resistance was shown to be due in most isolates to a transmissible plasmid. The need for monitoring the extended use of this valuable antibiotic is emphasized.

Numerical analysis of electrophoretic protein patterns of methicillin-resistant strains of Staphylococcus aureus

A total of 50 strains of Staphylococcus aureus, including 41 methicillin-resistant S. aureus (MRSA) strains, were characterized by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins. The protein patterns contained 40-50 discrete bands and were highly reproducible. Partial patterns were used as the basis of a computer-assisted numerical analysis. The MRSA strains clustered into four phenons at the 83% similarity level; and further division of phenon 1, at the 86% similarity level, resulted in a total of six clusters. All of the MRSA isolates from an MRSA epidemic in the United Kingdom were found to cluster in phenon 1 together with 9 of the 12 MRSA isolates from eastern Australia and 3 other MRSA isolates from the United Kingdom. The remaining three eastern Australian isolates clustered separately in phenon 2. Phenon 3 appeared to be exclusive to strains that were both susceptible and resistant to methicillin and that reacted with group V phages, and phenon 4 comprised 11 isolates, all of which were other MRSA isolates from the United Kingdom. We conclude that computer-assisted numerical analysis by high-resolution sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins provides additional criteria for the study of the epidemiology and the evolution of MRSA.

Plasmid profiling of epidemic staphylococci from around 1960: a comparison of epidemiological techniques

Plasmid profiles have been established for 68 isolates of Staphylococcus aureus from 13 episodes of epidemic spread in hospital wards between 1958 and 1962. Despite the original lack of care in preservation of strains the profiles give, in general, the same epidemiological patterns as were established originally on the basis of phage type, antibiotic sensitivity, ward and date of isolation.

Recipient characteristics in the transduction of methicillin resistance in Staphylococcus epidermidis

Methicillin resistance (Mecr) was transduced into a methicillin-susceptible variant of the Mecr donor Staphylococcus epidermidis BS10. UV irradiation of phage stimulated Mecr transduction frequency. If loss of Cd and Hg ion resistance occurred in this recipient, or if the three markers Mecr, Cdr, and Hgr were co-eliminated from the donor, neither strain acted as a recipient for Mecr.

Changing phage typing patterns of epidemic gentamicin-resistant Staphylococcus aureus. Evidence for transmission of gentamicin resistance

In a 10-week period, infection with gentamicin resistant Staphylococcus aureus appeared in 24 adults and infants in one hospital. Medical staff were affected first, and subsequently 16 infants in the neonatal intensive-care unit. The gentamicin-resistant staphyloccal isolates showed three distinct phage susceptibility patterns in two distinct phage groups during the early, middle, and late phases of the outbreak. Although not confirmed with in-vitro or in-vivo laboratory data, this outbreak suggests that gentamicin resistance may be transferred between different strains of Staph. aureus in vivo.

Bacteriophage types and antibiotic sensitivity of staphylococci from bovine milk and human nares

The number, phage types, and antibiotic sensitivity of coagulase-positive staphylococci from grade A raw milk samples produced on 40 farms in the Athens, Ga., milkshed were determined. Counts of mannitol-positive staphylococci in milk ranged from 100 to 3,580 per milliliter, with an arithmetic mean of 1,047. Examination of the nares of 48 dairymen on 34 of the farms also revealed that 13 (27%) were carriers of coagulase-positive staphylococci. Isolates from milk (412) and from nares (39) were tested against the Coles, Seto-Wilson, and International phage sets and 87, 68, and 56%, respectively, proved typable. Nine isolates were not typable. Each of the 33 phages used lysed one or more of the isolates. Staphylococcal phage types per milk sample ranged from 0 to 5, 0 to 7, and 0 to 8, with arithmetic means of 1.9, 2.3, and 2.3, respectively. Of the 13 narial carriers, 7 harbored staphylococci of one or more of the same phage types as those isolated from the milk at the respective farms. Randomly selected isolates were tested against high and low concentrations of 12 common antibiotics. All were either moderately sensitive or resistant to polymixin B. Over 30% were moderately sensitive or resistant to dihydrostreptomycin and penicillin individually. With but few exceptions, all isolates were sensitive to chlortetracycline, bacitracin, carbomycin, chloramphenicol, erythromycin, neomycin, novobiocin, oxytetracycline, and tetracycline individually.

Drug Resistance of Staphylococci I. Transduction of Tetracycline Resistance with Phage Lysates Obtained from Multiply Resistant Staphylococci

Mitsuhashi, Susumu (Gunma University, Maebashi, Japan), Hiroshi Oshima, Umeko Kawaharada, and Hajime Hashimoto . Drug resistance of staphylococci. I. Transduction of tetracycline resistance with phage lysates obtained from multiply resistant staphylococci. J. Bacteriol. 89: 967–976. 1965.—Tetracycline resistance was found to be transduced with phage lysates obtained from multiply resistant strains of Staphylococcus aureus of human origin. With various combinations of multiply resistant donors and tetracycline (TC)-sensitive recipients, almost all of the strains were found to be competent donors. A greater percentage of group 1 staphylococci were competent recipients. Most of the TC + transductants were not lysogenic for the transducing phage and were unable to transduce TC resistance with their own phage lysates obtained by ultraviolet irradiation. However, the TC + transductants, lysogenized with transducing phage, were capable of transducing TC resistance, and some of the lysogenizations were accompanied by changes in phage type. These results suggest that the emergence of the multiply resistant staphylococci (consistently resistant to TC) can be accounted for by transduction among various strains accompanied sometimes by changes in phage typing pattern after lysogenization, and by selection through extensive use of antibiotics and chemotherapeutic agents.

THE IN VITRO EFFECT OF LYSOSTAPHIN ON CLINICAL ISOLATES OF STAPHYLOCOCCUS AUREUS

Lysostaphin, an antibiotic that is unique inasmuch as it lyses all strains of Staphylococcus aureus, has been tested against 252 strains obtained from clinical sources. The clinical isolates were phage typed and tested for in vitro susceptibility to lysostaphin and seven other antistaphylococcal antibiotics.The resistant strains, found generally in phage groups I, III, and Insensitive, were most susceptible to vancomycin, lysostaphin, ristocetin, and kanamycin. The antibiotics least effective were penicillin G, tetracycline, phenethicillin, and erythromycin. As an attempt to quantitate the susceptibility of various clinical strains of 5.S. aureus to lysostaphin, a "lysostaphin index" was devised in which, by an arbitrary criterion, the susceptibility of a clinical isolate was related to the sensitivity of S. aureus, strain FDA 209P. It was found that all isolates were lysed by lysostaphin.

PHOSPHATASE ACTIVITY OF STAPHYLOCOCCUS AUREUS : CORRELATION OF ENZYME PRODUCTION WITH RESISTANCE TO PENICILLIN AND PHAGE PATTERN

Cannon, Frances D. (The Mary Imogene Bassett Hospital, Cooperstown, N.Y.), and Clinton V. Z. Hawn . Phosphatase activity of Staphylococcus aureus : correlation of enzyme production with resistance to penicillin and phage pattern. J. Bacteriol. 86: 1052–1056. 1963.—A simplified method for the determination of the phosphatase activity in different strains of staphylococci is described. The relationship between phosphatase production and penicillin resistance was studied and found inconstant. A close relationship between phosphatase production and phage group and type was observed.

Nomenclature of Devices Which Simulate Biological Functions

The suffix -mime is proposed to create generic names for the general class of man-made devices which simulate biological functions. The suffix is used after the stem of the word that describes the organ or cell being simulated; for instance, artificial neurons are described as neuromimes.