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Biomedical subjects

L W Wannamaker

Publications and source records attributed to L W Wannamaker.

At least 91 records · Page 5Linked to original sources
PubMed1972

Experimental infection of the skin in the hamster simulating human impetigo. IV. Cellular responses after streptococcal and staphylococcal infections.

Various cellular responses to skin infections in an experimental animal model were explored. Total leukocyte counts varied after group A streptococcal infections, but a depression was commonly seen after M type 12 impetigo. Staphylococcus aureus infections resulted in moderate leukocytosis. A marked neutrophilia was universal with streptococcal or staphylococcal disease. A positive nitroblue tetrazolium (NBT) response appeared 24 hr after infection, reached a peak in 48 hr, and then declined. This occurred in the absence of extensive cellulitis or bacteremia. An increase in the percentage and absolute number of NBT-positive neutrophils occurred. M type 57 streptococcus produced a more strongly positive NBT test than did M type 12. Cell-free filtrates of a broth culture of M type 57 streptococcus produced NBT responses in hamsters comparable to the responses seen after injection of live organisms. These studies indicate the usefulness of this animal model to study various parameters of the NBT test.

Animals↗
PubMed1972

Antibody responses to group A streptococcal infections in the hamster.

The immune response after streptococcal infections of the skin and of the joints was studied in an experimental animal model. Hamsters were challenged intradermally or intra-articularly with different streptococcal serotypes, and antibodies for streptolysin O (ASO), deoxyribonuclease B (anti-deoxyribonuclease B), and group A carbohydrate (anti-group A CHO) were determined. After a single injection at either site, 7 of 48 animals (14%) developed group A-CHO antibodies; however, none of the animals developed detectable levels of ASO or anti-deoxyribonuclease B. After repeated infections of the skin or joint, anti-deoxyribonuclease B antibodies were detectable in 13% (4 of 30) and 30% (5 of 17) of the animals, respectively. Elevations of ASO occurred after repeated joint infections in 4 of 16 animals (25%), whereas none of 30 hamsters repeatedly infected intradermally developed antibodies against streptolysin O. For all three antibodies tested, elevated levels were more frequently noted after repeated joint infections than after repeated skin infections with the same streptococcal serotype. These data, similar to ones previously noted in human impetigo, indicate that ASO responses are feeble after streptococcal skin infections and that the site of infection per se, rather than the infecting strain, appears to be responsible for this poor response.

Animals↗
PubMed1972

Natural history of impetigo. I. Site sequence of acquisition and familial patterns of spread of cutaneous streptococci.

The appearance on and spread of Group A streptococci among different body sites in relationship to the development of impetigo were studied prospectively in 31 children in five families. During July and August 1969 intensive clinical, bacteriological, and serological observations were made, including cultures taken at least every other day. In individual children, site sequence of spread of Group A streptococci was from normal skin to lesions and finally to respiratory tract. Streptococci were recovered from normal skin before development of lesions (mean interval of 10 days) in 74% of episodes. Recovery of streptococci from nose and throat followed (by means of 14 and 20 days, respectively) skin acquisition of streptococci (97% of episodes) and lesions (74% of episodes).Distribution of positive normal skin sites among wrist, ankle, and back was similar (28-37%) although 62% of lesions were on the legs. Recovery of a serotype from normal skin was associated with a high risk (76%) of subsequent development of lesions due to that type. New streptococcal serotypes usually entered a family during the peak or decline of a preceding serotoype with a tendency of one to predominate. Among family members the mean interval from index to secondary skin acquisition of streptococci was 4.8 days, but 21 days elapsed from first appearance to last acquisition of skin disease. In the population as a whole, streptococci were recovered in high frequency from normal skin before the increase in prevalence of lesions and also later in the fall when cutaneous infections were absent.

Adolescent↗
PubMed1972

Natural history of impetigo. II. Etiologic agents and bacterial interactions.

Intensive observations on 37 children in a population with endemic skin infections provided an opportunity to study the interrelationships between and the significance of the bacterial genera commonly associated with impetigo. Cultures of the respiratory tract, three normal skin sites, and lesions, when present, were taken three times weekly from July to October 1969. Impetigo developed in all 37 children. Group A streptococci alone were recovered from 21% of 361 lesions, Staphylococcus aureus alone from 8%, Staphylococcus epidermidis alone from 5% and mixtures of streptococci and staphylococci from 61%. Vesicular or pustular lesions were more often pure streptococcal than pure staphylococcal. Streptococci alone were more often recovered from early stage lesions rather than from later ones. The pure staphylococcal lesions characteristically occurred early in the season whereas streptococcal or mixed lesions had later peaks.Serial observations on 74 lesions revealed longer persistence of streptococci than staphylococci in mixed lesions. In 85% of the instances the same streptococcal serotype was recovered repeatedly from an individual lesion, whereas staphylococcal types changed in 57% of instances. Phage type 75 accounted for the majority of staphylococcal isolates from all sites, whereas phage type 54 was recovered only from skin lesions. In contrast to streptococci, the site sequence of staphylococcal spread was from the nose to normal skin to skin lesions. These studies reveal important differences in the migration of staphylococci (as compared with streptococci) to various body sites and suggest a subsidiary role for staphylococci in nonbullous impetiginous lesions yielding both organisms.

Adolescent↗
PubMed1971

Experimental infection of the skin in the hamster simulating human impetigo. III. Interaction between staphylococci and group A streptococci.

The interaction between staphylococci and Group A beta hemolytic streptococci in mixed lesions was investigated in an experimental impetigo model. A strain of staphylococcus of phage Type 71, which has been shown in vitro to produce a bacteriocin for streptococci and other Gram-positive organisms, eliminates or reduces Group A streptococci in mixed lesions. In contrast, staphylococcal strains of phage Types 75 and 81, which do not produce a demonstrable bacteriocin in vitro, exhibit no such effect. Some variation was noted in the in vivo response of two different streptococcal M Types to the bactericidal effect of phage Type 71 staphylococci. Bacterial antagonism is more pronounced when staphylococci and streptococci are injected simultaneously into animals than when staphylococci are superimposed on preexisting streptococcal lesions. Marked variations were found in the numbers of viable streptococci (colony-forming units) recovered from individual lesions containing identical mixtures of streptococci and phage Type 71 staphylococci. The frequency of a demonstrable bactericidal effect was related to the number of streptococci injected. With small inocula of streptococci, the tendency towards an all-or-none effect was particularly striking. No evidence of selection of streptococcal or staphylococcal mutants which might explain this phenomenon was obtained. These observations suggest that the bactericidal effect of phage Type 71 staphylococci on other Gram-positive organisms, previously demonstrated in vitro, appears to operate also in vivo.

Animals↗
PubMed1970

Bactericidal substance from Staphylococcus aureus. Biological properties.

A bactericidal substance previously isolated from phage type 71 Slaphylococcus aureus has been further identified and characterized. Staphylococci belonging to phage type 71 produce the substance in higher titers than staphylococci lysed by other phages in group II in addition to phage 71. Other staphylococci do not produce the bactericidal substance. The bactericidal substance shares several of the properties of bacteriocins but differs from this group of antibiotic substances in some respects. A combination of ammonium sulfate fractionation and gel filtration on a Sephadex G-100 column resulted in considerable degree of purification of the bactericidal substance. The substance is a previously unrecognized product of S. aureus and is distinct from other extracellular products of this organism.

Bacteria↗
PubMed1970

The role of normal skin in the spread of streptococcal pyoderma.

The primary body site of acquisition of group A streptococci was examined prospectively in a population with endemic streptococcal pyoderma. Weekly cultures were obtained during the skin infection season from apparently normal upper respiratory and cutaneous sites (and from skin lesions when present) in 44 children and adults living on the Red Lake Indian Reservation.During the 9-week period of the study 705 of a total of 2305 cultures were positive for group A streptococci. The percentage of positive cultures from the various sites were: throat (20%); nose (24%); wrist (32%); ankle (35%); back (22%); and skin lesions (81%). Group A streptococci were also isolated from fingernail dirt, clothing and bedding as well as from a few household pets and insects.Analysis of serial cultures obtained from the same individuals at weekly intervals suggested that the strains isolated from skin lesions first appeared on normal skin in the 2 weeks preceding the lesion. Spread to the nose and throat followed skin acquisition and/or skin lesions.The high prevalence of group A streptococci on normal skin in the absence as well as the presence of pyoderma, and their appearance on normal skin before recovery from either skin lesions or the upper respiratory tract are consistent with the view that skin acquisition was a primary predisposing factor to pyoderma. Since the literature indicates that group A streptococci are rarely part of the normal skin flora, these findings raise the possibility of unique biological properties of these and perhaps other pyoderma strains, as distinct from other group A streptococci.

Adolescent↗