Streptococcal serotypes newly associated with epidemic post-streptococcal acute glomerulonephritis.

The increasing incidence of reported scabies in Trinidad, from 24.2/100,000 population in 1984 to 59.5/100,000 in 1985, led to a careful monitoring in 1986 of all patients with post-streptococcal acute glomerulonephritis (PSAGN). There were 181 cases of PSAGN; 84 beta-haemolytic streptococcal isolates from 72 patients were sent to the Central Public Health Laboratory, Colindale, for grouping and serotyping. The PSAGN epidemic of 1986 was bimodal. Streptococci of M-type 73 appeared to be associated with the first phase (March-May) and comprised 20% of the isolates serotyped. New to Trinidad, streptococci of M-type 48 (4% of the isolates serotyped) preceded the first phase of the epidemic and were isolated from two patients with PSAGN. Provisional type (PT) 5757, also new to Trinidad, had been previously identified only among serotypes from the United Kingdom and the Federal Republic of Germany. This type was isolated from seven patients, in six from skin lesions and in one from the throat. PT 5757 occurred during the first wave of the epidemic and comprised 14% of the strains serotyped. Thus, the first wave of the bimodal epidemic involved serotypes M73, M48 and PT 5757. The more intense second phase (July-October) was associated with the previously documented nephritogenic M-type 55.