Biomedical subjects
Publications and source records attributed to M Gershman.
Out of 136 new phages, 80 (59%) are classified into 23 species according to morphology and physicochemical properties. Six new species are described and species beta 4, from a previous classification scheme, is renamed T1. The morphology of 36 phage species is schematically represented.
BACKGROUND: Outbreaks of invasive group A beta-hemolytic streptococcal (GABS) infections have recently been reported. We observed a high incidence of invasive GABS disease among Native Americans at a small rural community hospital between 1982 and 1991. METHODS: A retrospective chart review was performed, and all cases of invasive GABS disease were studied for their clinical features. RESULTS: Sixteen cases of invasive GABS infection were identified during the 10-year study period. The rate of invasive GABS infection was 13.3 cases per 100,000 population per year. Mortality was 25%. Nearly half of the patients presented with systemic signs of sepsis without any obvious source of infection. CONCLUSIONS: Our experience documents a high rate of invasive GABS infections in a defined Native American population. To determine whether this population has a unique susceptibility to GABS disease requires further study.
We studied the association of milkers' hands and milking unit liners as fomites, and teat skin as a reservoir, with S. aureus intramammary infections (IMI). Samples were collected from 40 commercial herds and S. aureus isolates were phage typed. Only 10 of 257 isolates were not typable. Of the milk samples, 8.4% had typable S. aureus; 4.5% and 9.2% of the skin and liner swabbings had typable S. aureus. Twenty-three different phage types were identified, 1 type was found in nearly 75% of the herds. Herds in which milking unit backflush was used were less likely to have the same phage type on the liners and the teat skin, and on the liners and milk samples, than herds that did not backflush. A greater percentage of liners had S. aureus of the same type as those causing S. aureus IMI, than skin swabbing solutions with the same type as that associated with IMI. Herds which did not use post-milking teat asepsis (teat dip) did not have a greater percentage of S. aureus isolates on the teat skin, nor were the S. aureus test skin isolates more likely to be of the same type as those causing intramammary infection. Results would suggest that the liner appears to be a significant fomite, that backflushing reduces its significance, and that teat skin is a less significant reservoir for S. aureus intramammary infection.
A phage typing set composed of 13 phages is described for characterizing Staphylococcus epidermidis. Isolates (372) from cases of bovine mastitis were used in this study. Of these, 350 or 94% were successfully delineated, and 63 phage types were observed. Twenty two cultures were not typeable.
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A phage typing set composed of 32 phages is described for differentiating Escherichia coli. Eight hundred sixty-six isolates from cases of bovine mastitis were used in this effort. Of these cultures 829, or 96%, were characterized successfully, and 178 phage types were observed. Thirty-seven isolates were not typable.
A set composed of 27 phages is described for differentiating Salmonella spp. representative of groups A, B, C1, C2, D1, D2, E1, E2, E3, E4, G1, K, and N. All of the 1,245 cultures used in this effort were typable and were differentiated on the basis of the 420 phage patterns observed. All results were reproducible. Characteristic phage patterns were produced by a variety of Salmonella serovars isolated from campus incidents and a number of hospital, family, restaurant, and processing plant outbreaks to indicate an existing epidemiological relationship.
During a survey in Jakarta, Indonesia, 158 cultures of Salmonella oranienburg, consisting of two phage types, were obtained from 150 hospitalized patients with diarrhoea. Phage type I, though found notably in young children, was found in all age groups while phage type II was found almost exclusively in young children aged 0-7 years. Phage type I may produce a more severe clinical picture affecting all age groups alike, while phage type II may result in hospitalization of only the very young, who are more susceptible to dehydration. Phage type I was significantly more resistant than phage type II to the individual antibiotics: tetracycline, chloramphenicol, kanamycin and neomycin. However, there was no difference in their respective antibiotic resistance patterns as measured by disk and MIC assay. All cultures were sensitive to gentamicin and trimethoprim-sulphamethoxazole 1:19.
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A phage-typing system is described for characterizing commonly isolated salmonellae. Fifty-eight serovars representative of groups A, B, C1, C2, D, E1, E2, E3, and E4 were delineated by using a single set of 50 phages isolated from sewage. All of the 735 cultures used in this effort were typable and were distinguished and differentiated on the basis of the 347 phage patterns observed. All results were reproducible. Characteristic phage patterns were produced by a variety of Salmonella serovars isolated from a campus incident and a number of hospital and family outbreaks to indicate an existing epidemiological relationship.
Day-old chicks were infected with Salmonella typhimurium. The impact on the intestinal mucosa was observed by scanning and transmission electron microscopy. Salmonella infected birds were characterized as having areas on their intestinal mucosal cells devoid of microvilli. The absence of microvilli probably interferes with absorption of the digesta.
A system is described for the phage typing of Salmonella enteritidis. The system was developed using a number of bacteriophages that were isolated from sewage.
Fifteen common serotypes representative of group C(1) and C(2)Salmonella were characterized using a single set of phages.
Eighteen common serotypes representative of group E(1), E(2), E(3), and E(4)Salmonella were characterized using a single set of phages.
A recently marketed reagent strip designed for clinical urinalysis, Microstix, has been found to be useful in rapid and simple examination of water sources for baby chicks.
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A system is described for the phage typing of Salmonella thompson. The system is based upon a number of bacteriophages that were isolated from sewage.
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