Streptococcal infection and renal disease markers in Australian aboriginal children

OBJECTIVE

To demonstrate an association between markers of streptococcal infection and markers of glomerulonephritis in Aboriginal children.

DESIGN

A cross-sectional study of Aboriginal children of school age.

SETTING

Three Aboriginal communities in the Northern Territory--two, coastal and one, desert.

PARTICIPANTS

Sixty children, randomly selected from the school roll, were studied in each community; thus there were 180 children in total, aged 5-17 years. Midstream urine and venous blood was collected and swabs were taken from the pharynx and from impetiginous skin lesions or axillary skin in the absence of impetigo. Clinical records were examined for evidence of past glomerulonephritis.

MAIN OUTCOME MEASURES

Swabs were cultured for beta-haemolytic streptococci and isolates were grouped; serum was tested for titres of antistreptolysin O (ASO) and antideoxyribonuclease B (anti-DNaseB). Protein and creatinine levels were measured in urine, and a ratio of protein to creatinine (UPC) of more than 50 mg protein per mmol creatinine was taken as a measure of significant proteinuria. Urine was examined microscopically for glomerular haematuria (greater than 10 red blood cells per microL with at least 20% dysmorphic red cells).

RESULTS

Group A beta-haemolytic streptococci were isolated from the throat swabs of two children and from skin swabs of 25 (13.9%) children; 20 of these were from impetiginous lesions and five from normal axillary skin. beta-Haemolytic streptococci of group C or G were grown from the throat swabs of 13 (8.1%) children. The median titre of ASO (256 IU) was raised compared with a reference level, and the median titre of anti-DNaseB (3172 IU) was particularly high; ASO titres were significantly higher in 31 children with impetigo than in 149 children without impetigo. Significant proteinuria was present in 7 (3.9%) children and glomerular haematuria in 16 (8.9%). Glomerular haematuria was present in 2/7 (28%) children with proteinuria, 4/21 (19%) children with a past history of post-streptococcal glomerulonephritis, in 5/31 (16%) of those with impetigo and in 4/25 (16%) of those with positive skin cultures. However, none of these prevalences was significantly greater than the prevalence of glomerular haematuria among the other children. The prevalence of proteinuria differed significantly between communities and increased significantly with age. Furthermore, the differences in childhood proteinuria observed between communities in this study were parallel with community differences in the prevalence of proteinuria in a related study of adults.

CONCLUSIONS

Group A streptococci are important causes of impetigo in Aboriginal children. Streptococcal skin infection may contribute to glomerular haematuria, proteinuria and persistent glomerulonephritis in Aboriginal children, and possibly to chronic glomerulonephritis in adult life. Public health programs are needed to reduce the prevalence of impetigo and group A streptococcal infections in Aboriginal communities; longitudinal studies are needed to test the relationship between streptococcal skin infection in Aboriginal children and chronic renal disease in later life.

[Common cold: diagnostic steps? Antibiotics?]

The common cold is caused by more than 100 virus types. However, the clinical manifestation is always similar with rhinorrhea, stuffiness, sneezing, pharyngitis, laryngitis and cough. The local inflammatory reactions are not due to the presence of virus but caused by locally produced inflammatory mediators. Bacterial superinfections may cause otitis or sinusitis. Bacterial nasopharyngitis has been described in children. This entity possibly exists also in adults. Traditional viral cultures are rarely positive and are not recommended in the daily routine. In children, antigen detection for adenovirus, respiratory syncytial virus, parainfluenza and influenza virus are recommended to confirm the viral etiology or for epidemiological surveillance. The presence of group-A streptococci must be proven by culture or antigen detection before treatment with penicillin. Antiviral treatment is limited to interferon or ribavirin. New antiviral substances are in development. Today, treatment of common cold is limited to symptomatic measures, and antibiotic treatment is not justified.

[Antistreptolysin O]

Automated analyzers based on the quantitative immunochemical methods have been developed and can allow quantitative measurements of antistreptolysin O concentrations in the clinical laboratories. Automated ASO determinations improve in point of operation, time, effort, precision and accuracy, compared with the usual semiquantitative methods of tube dilution techniques based on the method of Rantz and Randall or some modification thereof, microtitration of the Edward method and agglutination test using latex or other particles. However, confusion and many kinds of problems have been brought about by the rapid development of automated ASO measurements in routine use. The principle quantitative immunochemical measurements of automated ASO determinations are immune agglutination assays, which are nephelometric immunoassay (NIA), latex agglutination photometric immunoassay (LAPIA) and turbidimetric immunoassay (TIA). Principles and methods of these automated immunoassay, reagents, ASO standard serum, automated analyzers, precision and accuracy, the present conditions and problems of automated analysis in the clinical laboratories were discussed in comparison with usual semiquantitative measurements. There was a good correlation between automated immune agglutination assay (NIA, LAPIA and TIA) and the usual semiquantitative assay. However, the quantitative accuracy of automated immune agglutination assay was decreased in the regions of low and high ASO values. Availability, precision and accuracy of ASO measurement were improved by the automated analysis. However, the methods of ASO measurements were increased and varied by the automated assay. Therefore, it is necessary to standardize the automated ASO measurements. The limitation and the clinical significance of the automated immune agglutination assay of ASO have to be studied for practical use in the future.

[From qualification to quantification in immunoserological testings]

During the 1980's, quantifications of immunoserological testings, especially C reactive protein, rheumatoid factor and antistreptolysin O, progressed rapidly. However, marked interlaboratory differences in these quantifications have been observed. In this brief review, difficulties to satisfy requirements for good quantitative performance in immunochemical assays are discussed.

[Relation between foci of chronic oral infection, rheumatic fever and general or local anesthesia]

We make a study about Rheumatic fever diagnostical on boys who need an exeresis of bucals focus, which we make under general or local anaesthesia effects, and we verify the quantity of ASLO descent which depended on type of anaesthesia and the number of sessi that we make.

Evaluation of a new latex agglutination test for detection of streptolysin O antibodies

Acute- and convalescent-phase serum specimens were collected from 50 patients with group A streptococcal pharyngitis. The anti-streptolysin O (ASO) titer for each serum specimen was determined by using both the standard neutralization assay and the latex agglutination (LA) test (Rheumagen ASO; Biokit Inc., New Britain, Conn.). When the ASO titers derived by the two methods were compared, the correlation coefficient was 0.93. When the ability of the LA test to demonstrate a significant ASO titer rise (greater than or equal to 2 dilutions) was compared with that of the standard neutralization assay, the LA test had a sensitivity of 91%, a specificity of 86%, a positive predictive value of 83%, and a negative predictive value of 92%. Triplicate LA test determinations were performed on a subset of 31 serum specimens, and for 29 (94%), the repeated ASO titers were all within 1 dilution of each other; the width of the 95% confidence interval for the triplicate measurements of each serum specimen was +/- 32.8 IU. We found the Rheumagen ASO to be a simple, rapid LA procedure for measuring ASO titers that produces results that are highly reproducible, show little lot-to-lot variability, and are comparable to the ASO titers obtained with the standard neutralization assay.

[A critical review of the methods used in evaluating the antistreptolysin titre as a diagnostic index]

Authors review the most common laboratory tests showing an immunologic response caused by group A beta-hemolytic streptococcus infections. After a preliminary evaluation on characteristics and peculiarities of different methods the results obtained are compared with the usually employed systems. The survey of most common analytical methods and personal experience lead to confirm and emphasize the laboratory results supporting and confirming, without substituting, the clinical data.

Waning significance of anti-streptolysin O (ASO) titres in diagnosing streptococcal infections in Lagos, Nigeria

A total of 200 serum specimens comprising 100 specimens from patients with streptococcal disease conditions, 50 from patients with other diseases and another 50 specimens from apparently healthy individuals were collected from Lagos University Teaching Hospital and from various areas of Lagos metropolis and screened for the presence of anti-streptolysin O (ASO). For streptococcal disease conditions, other diseases and for apparently healthy persons, anti-streptolysin O titres above 250 iu/ml recorded for each category of clinical conditions in terms of the number examined were 34%, 36% and 28% respectively. It is therefore suggested that high anti-streptolysin O (ASO) titres occur in apparently healthy individuals with no history of streptococcal infection and individuals with disease conditions other than those of streptococcal origin. Consequently the diagnosis of streptococcal diseases based on high titres of ASO in Lagos, is not pathognomonic, should be interpreted with caution and must not be definitive since healthy individuals and others without streptococcal infections develop high ASO titres.

[Possibilities and prospects of multiparameter immunologic examination in the diagnosis and prognosis of rheumatoid arthritis]

The authors have analysed data from literature and their own results concerning multiparameter examination of the patients with rheumatoid arthritis. An effort has been made to establish a correlative relationship between changes in the following immunologic values: the level of rheumatoid factor, circulating immune complexes, antibodies to streptolysin-0 and immunoglobulin G; the number of T-lymphocytes and the quantity of natural cells of the killers and the hormone regulatory activity of thymus. Positive interdependence between the presence of rheumatoid factor and that of antibodies to streptolysin-0 as well as an increase in the content of circulating hormone complexes has been determined. In view of absence of one value which is strictly specific and compulsory for rheumatoid arthritis, it is only complex investigation that allows to describe the trends in changes of the immunologic state of the patient with rheumatoid arthritis.

Comparison of latex and haemolysin tests for determination of anti-streptolysin O (ASO) antibodies

A latex agglutination test was compared with the micro-titration haemolysin inhibition method for the detection of anti-streptolysin O (ASO) antibodies in 428 serum samples. After slight modification of the latex method to produce maximal agglutination good agreement was shown between the results obtained by the two methods. The latex test had a sensitivity of 83.6%, a specificity of 93.3%, a predictive positive value of 86.5% and a predictive negative value of 91.6%. It was convenient, required less labour than the haemolysin test, and permitted economic testing of small numbers of sera.

Immunological abnormalities in children with acute rheumatic carditis and acute post-streptococcal glomerulonephritis

Immunological functions were investigated in 10 children with acute rheumatic fever and 11 children with acute nephritis to try and elucidate the cause of heart damage in acute rheumatic fever. Children with acute rheumatic fever and carditis showed an increase in serum IgG, IgA and antistreptococcal antibodies during the acute stage. Lymphocyte transformation responses to phytohaemagglutinin and streptococcal antigens were reduced but this was due to a serum suppressor effect. After recovering from acute rheumatic fever a lymphocytosis and an increased lymphocyte blastogenic response to streptococcal antigen were found. T-cells, T-helper cells and T-suppressor cells showed some changes in acute rheumatic fever but these were not statistically significant in our study. None of the changes in immunological responses that were seen in acute rheumatic fever were found in acute nephritis. These results support the hypothesis that an abnormal immune response to streptococcal products is involved in the development of carditis and the other phenomena observed in acute rheumatic fever.

Comparison of three rapid methods for detection of antibodies to streptolysin O and DNase B

Three commercial systems were compared for ability to detect antibodies to streptolysin O (ASO) and DNase B (ADB). Streptozyme (Wampole Laboratories, Cranbury, N.J.) exhibited high sensitivity (100%) for detecting ASO but low sensitivity for ADB (22.2%). The LeapStrep (Organon Teknika, Malvern, Pa.) and Check-Spectra (Diagnostic Technology, Hauppauge, N.Y.) tests had low sensitivities for detecting ASO (35.3 and 21.4%, respectively) and ADB (22.2 and 33.3%, respectively).

Sera from patients with high titers of antibody to streptolysin O react with listeriolysin

Sera of patients with suspected rheumatic fever and elevated titers of antibody to streptolysin O were examined by an immunoblotting technique. All but two serum samples, which yielded relatively low titers, bound to a 60-kilodalton protein in the supernatant from a culture of Listeria monocytogenes, which presumably represents the listeriolysin.

The group A streptococcal carrier state. A reexamination

Streptococcal infection usually is defined as a positive throat culture with a serologic response to group A beta-hemolytic streptococci, and a patient with a positive throat culture and no serologic response is a streptococcal carrier. Studies suggest that streptococcal carriers should show little clinical response to antibiotic therapy when compared with patients with true streptococcal infections. Patients with acute pharyngitis were divided into three groups: group 1--38 patients with negative throat cultures; group 2--72 patients with a positive throat culture and a significant rise in streptococcal antibody titers; and group 3--77 patients with positive throat cultures and no significant rise in streptococcal antibody titers. Patients in group 2 and group 3 had a comparable and dramatic clinical response to antibiotic therapy that was considerably greater than the clinical response in the patients in group 1. These findings raise questions about the appropriateness of using streptococcal antibody responses to distinguish between the streptococcal carrier state and a true streptococcal infection.

Homogeneous liposome lysis assay for determination of anti-streptolysin O antibody titer in serum

We developed a liposome lysis assay for determining anti-streptolysin O antibodies (ASO) in human sera involving the use of carboxyfluorescein-entrapped multilamellar liposomes. This assay system was based on the inhibition of streptolysin O-induced liposome lysis by ASO. Briefly, after incubation of a given amount of streptolysin O with ASO for 30 min at 37 degrees C, carboxyfluorescein-entrapped liposomes composed of egg yolk phosphatidylcholine and cholesterol in a molar ratio of 1:1 were added to the mixture to determine the residual streptolysin O activity. Liposome lysis, detected as carboxyfluorescein release from the liposomes, was inversely proportional to the ASO titer. The results of within-run and between-run precision studies indicated that the liposome lysis assay is accurate and gives reproducible data. Bilirubin, hemoglobin, and triglycerides did not interfere with the liposome lysis assay. The ASO titers of 100 patient sera, evaluated by our new method and the Rantz-Randall method, showed good correlation.

Bacteriological and serological aspects of group A streptococcal pharyngotonsillitis caused by group A streptococci

Several bacteriological and serological variables were studied in connection with a clinical treatment trial in 212 patients with group A streptococcal pharyngotonsillitis. Anaerobic incubation was not superior to incubation in 5% CO2 in air for the detection of group A streptococci. Saliva cultures were inferior to conventional throat cultures in detecting group A streptococci. No strains from patients with recurrences were found to be tolerant to penicillin. In several patients (all asymptomatic), group C and G streptococci were found in follow-up cultures. Group A streptococci serology was more often positive after two months than after one month, also in patients without recurrence.

Immunological relation between serum antibodies against pneumolysin and against streptolysin O

The immunological relation between serum antibodies to pneumolysin and to streptolysin O was studied in patients with pneumococcal pneumonia (n = 40), patients with infections due to beta-haemolytic streptococci (n = 35), healthy human controls (n = 60) and in rabbits immunized with pneumolysin. There was no correlation between anti-pneumolysin and anti-streptolysin O titers (r = -0.279). The distribution of anti-pneumolysin titers in patients with high anti-streptolysin O titers did not differ from healthy controls. However, there was a tendency to increased or rising anti-streptolysin O titers in patients with pneumococcal infection. Antibodies obtained during pneumococcal infection might thus give false-positive reactions in the streptolysin O neutralization test. Serum antibodies to streptolysin O do not cross-react with pneumolysin in an ELISA. The pneumolysin ELISA for detection of pneumococcal disease will therefore not be disturbed by false-positive reactions due to antibodies directed against beta-haemolytic streptococci.

Characterisation of various intravenous immunoglobulin preparations

Five commercially available immunoglobulin preparations are characterised with regard to molecular weight distribution, immunoglobulin subclass distribution and antibody content. Preparations processed utilising enzymic or chemical modification demonstrate considerable variance of molecular weight species and subclass distribution when compared to native preparations. Similarly, cytomegalovirus and anti-streptolysin O antibody content is dramatically reduced in the modified preparations. Possible reasons for the differences are discussed. In-process inactivation of Human Immunodeficiency Virus is reviewed with regard to one of the native preparations.

Tests for streptolysin-O antibodies in health and suspected streptococcal infections in Saudi Arabia

'Upper limits of normal' antistreptolysin-O (ASO) titres were determined in various age groups in Saudi Arabia using the conventional haemolysin and the newer, passive agglutination (Blue-ASO) tests. The upper limit of normal values were found to vary with age, being the highest (166 Todd units or 1:320) among the school age children. Serum samples from 744 patients with various clinical manifestations associated with streptococcal infections such as rheumatic fever, glomerulonephritis, tonsillitis, rheumatoid arthritis and polyarthritis were tested by both methods, with the geometric mean titres (GMT) being determined in each age group. In case of school age children with suspected rheumatic fever, and found positive by the tests, a GMT of 458 Todd units (1:1080) was obtained--much higher than the ASO levels detected in positives with glomerulonephritis or tonsillitis. Apart from its relative simplicity, rapidity and ease of performance, the Blue-ASO test was able to detect positivity in 15% of sera from patients of various age groups with suspected rheumatic fever, polyarthritis and tonsillitis who exhibited insignificant levels of ASO by the haemolysin test.

Dilemmas of streptococcal pharyngitis

Although the Group A beta-hemolytic streptococcus is the most common cause of acute bacterial pharyngitis in childhood, the clinical diagnosis is often not straightforward and throat cultures are advisable. To avoid unnecessary antibiotics, treatment should be delayed until culture results are available. Patients with negative cultures should discontinue any antibiotics already started on clinical grounds. Positive cultures may represent a carrier state, which can be identified by serologic studies.