Changing types of nephritogenic streptococci in Trinidad

The relation of seven different M types of streptococci to acute glomerulonephritis associated with skin lesions in South Trinidad has been studied by means of type-specific antibody assays as well as by isolation and identification of the strains. The data indicate that, one after another, five of these strains have prevailed among patients with acute glomerulonephritis during the past five years. At least three of the strains (M-types 55,49,57, and/or 60) were associated with epidemic increases in nephritis cases. The appearance of five consecutively predominant types of nephritogenic streptococci during a relatively short period of time is in contrast to the continuing prevalence of M-type 12 strains among nephritogenic streptococci primarily associated with respiratory infections in temperate zones. These observations suggest that the skin sores commonly found on children in tropical Trinidad, provide a particularly suitable environment for development of nephritogenic types. It remains to be seen whether these types will recur or whether new types will continue to emerge in Trinidad. (AU)

Streptococcal strains associated with different phases of epidemic acute nephritis in Trinidad

We will present bacteriological evidence for an association of acute glomerulonephritis with several streptococcal strains isolated from skin lesions in Trinidad; Types 52 and 55 during the first wave and type 49 during the second wave of the 1964-65 epidemic; atypical "type 2" in a sub-epidemic rise in cases during an endemic year; type 57 during a subsequent epidemic period; and type 60 most recently. Immunological confirmation of association of these strains with acute glomerulonephritis was obtained only for type 55. Low incidence of serum type specific antibodies to types 49 and "type 2" may be attribued to their poor antigenicity. However, this is not the case with type 57. Emergence of at least five and perhaps six apparently new types of nephritogenic streptococci during a relatively short period suggests that each recurrent epidemic wave of acute nephritis is the result of a newly introduced or newly developed strain of nephritogenic streptococci. Several questions might be asked: From where do these different types come?. Are they brought into Trinidad from outside or do they represent local mutants? Does a skin infection represent a particularly suitable environment for development of new streptococcal antigens? (AU)

Streptococcal skin infections and epidemic acute nephritis in Trinidad

We have presented bacteriological evidence for an association of acute glomerulonephritis with several streptococcal strains isolated from skin lesions in Trinidad: Types 52 and 55 during the first wave and type 49 during the second wave of the 1964-65 epidemic; atypical "type 2" in a sub-epidemic rise in cases during an endemic year; type 57 during a subsequent epidemic period; and type 60 most recently. Immunological confirmation of association of these strains with acute glomerulonephritis was obtained only for type 55. Low incidence of serum type specific antibodies to types 49 and "type 2" may be attributed to their poor antigenicity. However, this is not the case with type 57. Emergence of at least five and perhaps six apparently new types of nephritogenic streptococci during a relatively short period suggests that each recurrent epidemic wave of acute nephritis is the result of a newly introduced or newly developed strain of nephritogenic streptococci. Several questions might be asked: From where do these different types come? Does a skin infection represent a particularly suitable environment for development of new streptococcal antigens? (Summary)

Streptococcal surveillance of two South Trinidad school populations: a preliminary report

An Intensive Streptococcal Surveillance of two South Trinidad Schools differing in topographical surroundings and ethnic composition has been done for five months. Throat and skin sore cultures were obtained from samples of children of volunteer families. Additional cultures were obtained from non-sample schoolmates who developed skin sores. The data and findings are as follows: 1. Skin sores were found mainly on the extremities. 2. Males have more skin sores than females in a ratio of over 2:1 for males versus females. 3. The highest incidence of skin sores, was found in the five to six (5-6) year old population. 4. In the school sample 22.7 percent developed skin sore, 68.8 percent were positive for Beta-hemolytic Streptococci and 79.4 percent were Group-A. 5. 78.9 percent of all skin sores contained Beta-hemolytic Streptococci. 6. 77.3 percent of Beta-hemolytic Streptococci were Group-A. 7. The prevalence and incidence of skin sores, Beta-hemolytic Streptococci and Group-A Streptococci was highest at the end of December. (The end of the wet season). 8. 18.7 percent of the subject studied had Beta-hemolytic Streptococci in their throats; of these 25.4 percent were Group-A. 9. Of other streptococcal groups - throat cultures were high in Group-G while skin sores were high in Group-C. 10. The mean length of time that Beta-hemolytic Streptococci remained in skin sore was four (4) weeks. Sores themselves may be the reservoir for Group-A Streptococci. 11. The mean length of time that Beta-hemolytic Streptococci remained in the throat was two (2) weeks(Summary)

Staphylococci and streptococci in skin sores of South Trinidad acute glomerulonephritis patients and members of their families

These findings represented a study covering a period of ca. 5 months beginning September 1966. In this time, 75 cases of acute glomerulonephritis were investigated. Skin lesions of these patients were examined for B-hemolytic streptococci and coagulase-positive staphylococci. The families of the patients, totalling 486 individuals (exclusive of the patients) were similarly studied. Patients were cultured immediately on admission to hospital while their families were cultured usually within 4-5 days of admission of the patient. The majority of the lesions were traumatic in origin being the result of arthropod bites, cuts and bruises. Lesions were far more prevalent on the legs than elsewhere. Together, the legs and arms accounted for 90 percent and more of the lesions, 41.3 percent of the patients had lesions, this being twice the rate amongst the families .The occurrence of streptococci alone or staphylococci alone were rare events. However, the occurrence of staphylococci or streptococci in a skin lesion were independent events. Amongst cases, streptococci were found in 67.7 percent of the skin lesion, staphylococci in 93.5 percent, both organisms being found together in 61.3 percent. Comparable figures for the family group 66.0 percent, 74.2 percent, and 52.6 percent respectively. In both patients and families, skin sore if they contained streptococci, then the chances were high that the organisms would be Group A. Coagulase-positive staphylococci were found to occupy all categories with respect to pigmentation and heamolysis of sheep RBC, namely, white non-haemolytic, white haemolytic, golden heamolytic and the most common golden haemolytic. Haemolysis of sheep RBC and pigmentation of staphylococci did not influence the independence of staphylococci and streptococci. We were unable to commit ourselves as to whether staphylococci played any specific role in the aetiology or the course of the illness. Several hypotheses were suggested, for example, a synergestic action between staphylococcal products and streptococcal antigens, genome exchange between staphylococci and streptococci inducing nephritogenicity in the streptococci and immobilization of host defences by staphylococci leaving the host open to streptococcal attack. It was suggested that since skin sores acted as reservoirs for streptococci, antibiotic therapy of individuals with skin sores could control the disease. We point out that the widespread presence of staphylococci constituted a factor of immense importance to be considered in any prophylaxis and control programme. Any large-scale control programme using antibiotics could be expected to lead to the emergence of resistant staphylococci which would not only nullify the programme but would lead to other public health problems (AU)

Acute glomerulonephritis studies of the streptococcal disease unit

The Streptococcal Disease Unit of San Fernando, Trinidad, is a part of the National Nephritis Control Programme of the Ministry of Health of Government of Trinidad and Tobago. During the last fiscal year the Unit has reconstructed the descriptive epidemiology of recent acute glomerulonephritis and acute rheumatic fever. It has also investigated and followed up hospital cases of acute nephritis, visited families of nephritics, and kept under surveillance a probability sample of South Trinidad families and two schools. The 1965 acute nephritis epidemic wave in South Trinidad was bimodal and contained over 1,000 cases. The wave began in August (1964) crested in February, throughed in June, and recrested in September before descending to the former endemic level. Acute rheumatic fever followed a paradoxical course with 1964 admissions significantly exceeding 1965 admissions. Acute nephritis was most common in preschool children, males, East Indians. No primary geographic focus for the epidemic could be discovered. Analysis of socioeconomic facets of 1966 cases revealed that nephritis families were larger, had more preschool children, earned less, were more crowded, and more rural. On the other hand, nephritis and surveillance families did not differ in housing quality, nearby agriculture, or water supply. When antistreptolysin O titers among nephritis families and cases are compared to the surveillance population, titers among cases and their families are distinctly higher. Bouts of skin sores frequently preceded acute nephritis but not acute rheumatic fever. Age adjusted skin sore prevalence is significant greater among nephritis families than among surveillance families. Skin sores are most prevalent in preschool children and are unusual after age 15. Five per cent of all studied individuals have group A beta hemolytic streptococci in the pharynx. However, group a streptococci from skin sores, as well as skin sores, are significantly more prevalent in nephritis patients and members of their families. Skin sores harbour over one-half the group A streptococci present in the general population, over three-quarters among nephritis families, and over four-fifths among nephritis patients. Skin sore group A streptococci are largely if not completely independent of group A streptococci in the pharynx or external nares. This independence is not a feature of colonization by group C or group G streptococci. The external nares are infrequently colonized with group A streptococci. Pharyngeal colonization is short-lived but skin sores of a single individual may contain group A streptococci for several months. Thus, skin sores are the most important reservoir of group A streptococci in the studied population (see later paper). Genesis of skin sore pivots about arthropod bites, (i.e. mosquitoes, sandflies,) and host hypersensitivity. Bacterial invasion of skin sores results from direct contact with another infected person or from feeding flies of the genus Hippelates. Skin sores cannot be prevented but invasion by group A streptococci may be preventable. Thus most acute nephritis also may be preventable. Subsequent investigations of the unit wil be devoted towards the goal of preventing group A streptococcal colonization of skin sores (AU)