Cervical secretions in pregnant women colonized rectally with group B streptococci have high levels of antibodies to serotype III polysaccharide capsular antigen and protein R

Group B streptococci (GBS) colonizing the female genital tract will often infect newborn infants during delivery. In 200 pregnant women studied, 14% were colonized with GBS in the cervix, 12% in the rectum, and 9% in both cervix and rectum. We have previously reported that antibody levels to GBS serotypes Ia, II, and III in sera and cervical secretions were increased in women colonized in the rectum and/or cervix, when analyzed by a whole-cell ELISA. Here, we report the levels of antibodies to GBS serotype III capsular polysaccharide antigen (CPS III) and to protein antigen R4, which are present in most GBS III strains. Compared to culture-negative women, the group of women colonized rectally had markedly elevated levels of immunoglobulin (Ig)A and IgG antibodies in cervical secretions to both CPS III and protein R4 (P < 0.01 and P < 0.001, respectively). In sera, the corresponding differences between culture-negative and culture-positive women were less pronounced, or not present. In contrast to antibody levels to whole-cell GBS, antibody levels to CPS III and protein R4 in cervical secretions were not significantly increased in women colonized only in the cervix, except that IgA antibodies to protein R4 were slightly elevated (P < 0.05). These findings suggest that capsular type-specific polysaccharides and protein R4 in a mucosal vaccine might induce protective antibodies against GBS colonization of the uterine cervix.

Antibiotic and prednisolone therapy of erysipelas: a randomized, double blind, placebo-controlled study

112 patients admitted to hospital with a diagnosis of erysipelas, were randomized to 8 days treatment with prednisolone or placebo in addition to antibiotics. 108 patients received the study drugs and were evaluated for time to cure, which was the primary end-point. The median healing time was significantly shorter in the prednisolone group, 5 days, vs 6 days in the placebo group (p < 0.01). The 90th percentile healing time was 10.0 days in the prednisolone group vs 14.6 days in the control group. The prednisolone-treated patients had a median length of hospital stay (secondary end-point) of 5 days vs 6 for the placebo-treated (p < 0.01). The median treatment time with intravenous antibiotics (secondary end-point) was 4 days in the placebo group, which was 1 day longer than in the prednisolone group (p < 0.05). 13 patients, 7 of whom received placebo, relapsed during the observation period of 3 weeks. The frequency of side effects attributable to the study drug was not higher in the prednisolone group.

The relationship between the use of flucloxacillin, vancomycin, aminoglycosides and ciprofloxacin and the susceptibility patterns of coagulase-negative staphylococci recovered from blood cultures

Antibiotic use is a cause of selection of multiresistant bacterial strains. Over three years (1990-1992) we studied the relation between the use of flucloxacillin, vancomycin, aminoglycosides and ciprofloxacin and the susceptibility of coagulase-negative staphylococci (CNS) recovered from blood cultures. Although there was no increase in the use of flucloxacillin, the susceptibility of CNS to this antibiotic decreased from 25% to 6%. No increase in aminoglycoside use was seen, though the use in the non-surgical intensive care unit was 40 times the average use in the hospital. The susceptibility to gentamicin declined from 36% to 15% for the rest of the hospital and to zero for the non-surgical intensive care unit. Vancomycin use did not change in the hospital as a whole, but the use in the haematological unit was about ten times that in the rest of the hospital. No single resistant strain (vancomycin MIC > or = 4 mg/L) was found. A three-fold increase in ciprofloxacin use was seen. After a decline in the susceptibility to ciprofloxacin from 72% to 58% in 1991, there was a small recovery to 62% in 1992. The use in the haematological unit was about 20 times that in the rest of the hospital. Ciprofloxacin susceptibility declined from 40% to 25% in that unit in 1991. In 1992 there was a small recovery to 29%.

Use of physiologic variables to predict milk yield after clinical mastitis in dairy cattle

OBJECTIVE

To determine the association between intramammary infections caused by various bacteria and hepatic damage, as measured by serum sorbitol dehydrogenase (SDH) activity, WBC counts, and PCV and the association of clinical variables with milk production after a case of clinical mastitis.

DESIGN

Prospective, cohort study.

ANIMALS

82 cows with clinical mastitis.

PROCEDURE

Information on milk production, mastitis status, and selected physiologic variables was collected during a 1-year period. Milk samples for bacteriologic evaluation were collected on day 1 of an episode of clinical mastitis. Physical examination was performed and blood samples for laboratory evaluation were collected on days 1, 5, and 9. Primary outcome was mature equivalent 305-day (ME305) milk production. Correlations were assessed using a multiple regression model.

RESULTS

Higher WBC counts were associated with higher ME305 values. For cows with coliform mastitis, increases in SDH values were associated with higher ME305 values. For cows with coliform and streptococci/staphylococci mastitis, PCV was associated with ME305 values. Higher PCV values were associated with lower ME305 values for streptococci/ staphylococci and coliform infections.

CLINICAL IMPLICATIONS

The association between milk production and WBC count indicated that cows mobilizing WBC were better able to neutralize mammary gland infections, which may result in better milk production. The association between milk production and PCV suggested that maintaining hydration in cows with clinical mastitis may be a critical aspect of treating all cows with mastitis.

Effect of transportation on lower respiratory tract contamination and peripheral blood neutrophil function

OBJECTIVE

To evaluate the effect of transportation on lower respiratory tract contamination and peripheral blood neutrophil function in horses and to compare results from transported horses with those obtained in earlier experiments from horses confined with heads elevated.

DESIGN

A prospective study.

PROCEDURE

Six horses were transported by road for 12 h. Clinical and haematological examination, transtracheal aspiration and cell function studies were conducted before and after transportation. Results obtained after transportation were compared to pre-transportation values.

RESULTS

After transportation, peripheral blood leucocyte and neutrophil numbers were increased and rectal temperatures were evaluated. Transtracheal aspirates showed an accumulation of purulent respiratory tract secretions with increased numbers of bacteria, particularly beta-haemolytic Streptococcus spp and members of the Pasteurellaceae family. Three horses also had increased numbers of bacteria from the Enterobacteriaceae family relative to corresponding samples from earlier studies. Phagocytosis by peripheral blood neutrophils was significantly reduced, while the oxidative burst activity of peripheral blood leucocytes was either unchanged or enhanced.

CLINICAL IMPLICATIONS

Bacterial contamination of the lower respiratory tract occurs as a routine consequence of transportation of horses and is likely to be an important determinant in the development of transport-associated respiratory disease. Inflammatory airway secretions and increased numbers of bacteria were rapidly cleared, without clinical evidence of significant pulmonary disease and without additional treatment, in normal horses that were allowed to lower their heads after transportation. Peripheral blood neutrophilia and a reduction in neutrophil phagocytic function were evident for at least 36 h after transportation, suggesting that horses may require a number of days to recover from the stress of transportation. As the potential role of bacteria from the Enterobacteriaceae family in the development of transport-associated respiratory disease has not been elucidated, horses which develop clinical disease following transportation should undergo thorough bacteriological investigation to ensure appropriate treatment.

Therapeutic potential of human antisera to group B streptococcal glycoconjugate vaccines in neonatal mice

Experimental immunoglobulin preparations for treatment of group B streptococcal (GBS) infections contain low levels of functional antibody and exhibit lot-to-lot variability. GBS capsular polysaccharide-protein conjugate vaccines have recently been shown to produce high serum levels of type-specific antibody in healthy volunteers. Treatment of neonatal mice 4 h after inoculation with an ordinarily lethal dose of GBS type Ia, Ib, or III with pooled human serum from adults who had received GBS type Ia capsular polysaccharide-tetanus toxoid vaccine (Ia CPS-TT), Ib CPS-TT, or III CPS-TT resulted in 63%, 70%, and 75% survival, respectively. In contrast, < or = 17% of the infected mice treated with normal human serum or saline survived. These results demonstrate the therapeutic activity of GBS polysaccharide conjugate vaccine-induced antiserum and provide a rationale for the use of these vaccines in producing a functional, high-titered intravenous immunoglobulin preparation for clinical use.

Blood-brain barrier permeability during the development of experimental bacterial meningitis in the rat

In an attempt to examine whether routes of bacterial entry into the central nervous system have any bearing on subsequent changes in blood-brain barrier permeability, we examined cerebrospinal fluid (CSF) penetration of circulating 125I-albumin in two different models of experimental meningitis due to K1 Escherichia coli, type III group B streptococcus, or Haemophilus influenzae type b in infant rats: hematogenous meningitis subsequent to subcutaneous inoculation of bacteria vs meningitis induced by direct inoculation of bacteria into the CSF via the cisterna magna. In the model of hematogenous meningitis, the mean CSF penetration was significantly greater in animals with H. influenzae type b meningitis than in those with meningitis due to K1 E. coli or type III group B streptococcus. In contrast, the mean CSF penetration was significantly enhanced in all animals with meningitis induced by intracisternal inoculation regardless of infecting pathogens. Tumor necrosis factor activity in CSF appeared to correlate with the functional penetration of circulating albumin across the blood-brain barrier in both models of experimental meningitis. These findings suggest that the alterations of blood-brain barrier permeability during development of experimental meningitis may vary for different models of inducing meningitis and that the mechanisms responsible for these different permeability changes may be multifactorial.

Circulating neutrophils in septic preterm neonates: comparison of two reference ranges

OBJECTIVE

To study the effect of sepsis on circulating neutrophils in very low birth weight neonates and to assess the usefulness of recently revised reference ranges for circulating neutrophils in the diagnosis of sepsis in this population by comparison with previously reported reference ranges.

METHODS

Neutrophil parameters (absolute total neutrophils, absolute total immature neutrophils, and the immature:total neutrophil proportion) were analyzed retrospectively in 202 sepsis episodes in 192 neonates (birth weight = 1055 +/- 246 g, X +/- SD; estimated gestational age = 29 +/- 2 weeks) between birth and 30 days of age. The percentage of values lying outside the reference ranges reported recently by Mouzinho et al and previously by Manroe et al were compared. To more accurately assess possible differences in specificity between the two reference ranges, neonates with early-onset group B streptococcal infection (n = 19) were compared with a matched control group (n = 51) using conditional logistic regression.

RESULTS

Greater sensitivity was observed using the previous reference ranges of Manroe et al over the entire study period (0 to 720 hours) both for the initial and the second complete blood count (CBC). The previous reference ranges also were more sensitive than the revised ranges for the initial CBC at 0 to 72 and at 73 to 720 hours and for infections attributable to coagulase-negative staphylococci. However, specificity in neonates without group B streptococcal infection was significantly greater with the revised reference ranges compared with those of Manroe et al (initial CBC, 73% vs 45%; serial CBCs, 59% vs 10%).

CONCLUSION

The observed differences in sensitivities may be of limited clinical significance because very low birth weight infants often are begun on antibiotic therapy regardless of laboratory values. However, the striking differences in specificity using the revised reference ranges suggest that these ranges may be clinically useful in determining length of antimicrobial therapy in infants in whom cultures remain sterile.

Acute-phase proteins in perinatal human plasma

Plasma from eight newborns (4 pre-term and 4 full-term) with early-onset (< 72 h) sepsis and six apparently healthy controls was analyzed. The presence of spots identified as haptoglobin and serum amyloid A protein was the electrophoretic result most consistently associated with disease. Time course monitoring showed rises, peaks and declines of spot intensity as expected for acute-phase proteins induced by transient stimuli. Haptoglobin beta chains appear to be undersialated in pre-term newborns, whereas post-translational modifications of alpha chains and serum amyloid A protein are similar to those observed in adults. The undersialation of beta chain and occurrence of alpha chain phenotypes different from those found in maternal serum indicate that perinatal haptoglobin originates from neonatal synthesis.

Urinary nitrite excretion in low birth weight neonates with systemic inflammatory response syndrome

Increased nitric oxide (NO) levels are thought to play an important role in the pathophysiology of the systemic inflammatory response syndrome (SIRS) which is caused by disseminated vascular endothelial damage. Clinical studies have shown that urinary nitrite (NO2-) and nitrate (NO3-) excretions can be utilized as indexes of NO formation. The SIRS and NO relationship was investigated in 15 neonates with SIRS, gestational age 32.5 +/- 4.4 weeks and weight 1,737 +/- 753 g. The control group comprised 18 neonates with a gestational age of 32.8 +/- 3.5 weeks and a weight of 1,778 +/- 538 g. There was no significant difference in birth weights and gestational ages between the two groups (p > 0.05 and p > 0.05). The urinary nitrite levels obtained in the subjects were normalized for urinary creatinine concentrations. The mean urinary nitrite levels in the control group neonates were found to be 4.22 +/- 1.8 micromol/mmol creatinine on the 1st day, 4.09 +/- 2.28 on the 2nd, 3.62 +/- 1.6 on the 3rd, and 4.01 +/- 1.12 micromol/mmol creatinine on the 7th day. There were no statistically significant differences between these levels (p > 0.05). We determined urinary levels of nitrite in neonates in the study group within the first 24 h of SIRS symptoms and found these levels (18.35 +/- 11.16 micromol nitrite/mmol creatinine) to be elevated as compared with those of the control subjects on the 7th day of life (p < 0.0005). In conclusion, urinary nitrite excretion is significantly elevated in neonates with SIRS due to septic events, and these results suggest that NO might play a part in SIRS.

[Serologic study in patients with streptococcal infective endocarditis]

BACKGROUND

Infective endocarditis is a systemic disease in which there are a continuously antigenic stimulation of immunologic system. Streptococcus is still the most frequent cause of infective endocarditis.

PATIENTS AND METHODS

We investigated the presence of antibody (AB), total and IgM by indirect immune fluorescence technique, in four groups of population: streptococcal infective endocarditis (SIE), streptococcal bacteraemia (SB), Staphylococcus aureus endocarditis, and healthy people. Antigens used were: 1) their own strain isolated from the blood of patients with SIE and SB ¿homologous AB¿, and; 2) seven species of Streptococcus: Streptococcus intermedius, Streptococcus salivarius, Streptococcus bovis, Streptococcus sanguis I, Streptococcus sanguis II, nutritional dependent streptococci and Enterococcus faecalis (heterologous AB).

RESULTS

Homologous antibodies: titers > or = 1/512 were found in all patients with SIE and only in 2 with SB (sensitivity 100% and specificity 93%). IgM titer (threshold 1/32) was positive only in patients with SIE (sensitivity 75,5% and specificity 100%). The fall of the AB titer was continuous and slow, despite the good clinical evolution of patients. (AB titers were > or = 1/512 and IgM > or = 1/64 in 30% of patients 1 year later). Heterologous AB: in spite of statistically significant difference found in SIE versus the other groups, sensitivity of this test (threshold 1/256) is low, confidence interval include expected random value (50%), specificity is 88%.

CONCLUSIONS

The utility of homologous AB for diagnosing infective endocarditis is demonstrated. On the contrary for heterologous AB, antigenic common fractions must be found in the different species.

Equine herpesvirus type 2: prevalence and seroepidemiology in foals

Whole blood and serum were collected from foals to determine the prevalence of Equine herpesvirus type 2 (EHV 2) infection in foals, age at which infection can first be identified and serological responses to infection. Equine herpesvirus type 2 was isolated from peripheral blood mononuclear cells (PBMC) from 68 of 69 foals, 1-8-months-old, sampled once. Virus isolation was performed twice at intervals of 2-7 months on PBMCs from 33 foals and EHV2 was isolated on both occasions in all but one foal (negative, then positive). Regression analysis of log2-transformed reciprocal serum EHV2 virus neutralising (VN) titres revealed that in foals age 1-7 months, EHV2 VN antibody titre was positively correlated with age (r = 0.94). Paired serum samples were obtained from 58 foals, with the first samples collected age 1-6 months and the second samples collected 2-4 months later. There were significant (P < 0.05) increases in mean VN titres to EHV2 in foals sampled initially at age 1-4. Eight foals had blood sampled prior to sucking and at age 7, 20, 30 and 45 days. Each foal was negative for EHV2 in PBMC and each foal had a negative serum EHV2 VN titre immediately after birth. Each foal was positive for EHV2 in PBMC by age 45 days, with the earliest isolation at 25 days. Tracheal aspirate fluid and peripheral blood were collected from 20 foals without clinical signs of respiratory disease and from 30 foals with clinical signs of lower respiratory disease. In 20 foals without clinical signs of respiratory disease, EHV2 was isolated from tracheal aspirates (1/20 foals) and PBMC (20/20 foals) and in 30 foals with such clinical signs, from trachea aspirates (20/30 foals: P < 0.01) and from PBMC (30/30 foals). In one 6-month-old foal, EHV1, but not EHV2, was isolated from the tracheal aspirate, 3 months after EHV2 had been isolated from a tracheal aspirate. These results demonstrate a greater prevalence of EHV2 in lower respiratory secretions in foals with clinically apparent lower respiratory disease, but a cause and effect relationship between the virus and lower respiratory disease remains to be elucidated. It is noteworthy, however, that of virus isolations performed on 50 tracheal aspirates, a virus (EHV1) other than EHV2 was isolated only once.

Levels of cytokines and cytokine inhibitors in the neutropenic patient with alpha-hemolytic streptococcus shock syndrome

The pathogenesis of alpha-hemolytic streptococcus shock syndrome (SS), a life-threatening complication in neutropenic patients following aggressive chemotherapy that is caused by viridans streptococci, is unknown. We measured serum concentrations of proinflammatory and antiinflammatory cytokines and T cell activation markers in two patients with lethal alpha-hemolytic streptococcus SS. The results were compared with those for controls, two neutropenic patients with uncomplicated bacteremia due to gram-positive organisms and four patients with neutropenia and bacteremia due to gram-negative organisms (two of whom had lethal septic shock). In patients with alpha-hemolytic streptococcus SS, levels of interleukin (IL) 1 were undetectable, levels of tumor necrosis factor (TNF) alpha were only slightly elevated, and IL-6 was the only proinflammatory cytokine that was found in high concentrations and had a late peak level at the time of clinical deterioration. IL-6 levels were much higher in patients with alpha-hemolytic streptococcus SS than in controls with uncomplicated bacteremia due to gram-positive organisms but were comparable with those in controls with bacteremia due to gram-negative organisms. Soluble TNF receptor fragments and IL-1 receptor antagonist apparently were not protective despite high serum concentrations.

Optimal gentamicin therapy in preterm neonates includes loading doses and early monitoring

Recent studies have suggested the inadequacy of an initial gentamicin 2.5 mg/kg standard dose in neonates and the need for a loading dose. The purpose of this prospective, randomized study was to compare initial peak and initial trough serum gentamicin concentrations (SGC) in neonates after a standard dose (2.5 mg/kg) or a loading dose (4 mg/kg) on the first day of life. A secondary objective of the study was to evaluate the use of two SGC drawn after the first dose in designing individualized dosage regimens, despite the many changes in gentamicin disposition that occur over the first week of life. Forty infants admitted to the NICU were randomized to receive either 2.5 or 4 mg/kg gentamicin. Individual gentamicin pharmacokinetic parameters were determined after the first dose. Initial peak SGC were > 5 mcg/ml in only 6% of neonates receiving 2.5 mg/kg, versus 94% of neonates receiving 4 mg/kg. The initial trough after the first dose was < 2 mcg/ml in 100% of patients receiving 2.5 mg/kg and only 39% of patients receiving 4 mg/kg. Using two SGC after the first dose successfully predicted steady state peaks in 13/16 infants and steady state troughs in 14/16 infants. Thus, standard treatment of 2.5 mg/kg gentamicin yields initial peak serum gentamicin concentrations < 5 mcg/ml in neonates while a 4 mg/kg gentamicin loading dose, combined with pharmacokinetic monitoring after the first dose, optimizes gentamicin therapy in neonates.

Antibiotic susceptibility of pneumococci isolated in Austria over a four-year period

The antibiotic susceptibility of pneumococci isolated from clinical specimens from 1991 through 1994 was investigated. Of 305 strains tested by the agar dilution method, 16 (5.2%) were resistant to penicillin (MICs > or = 0.12 mg/l). Of the resistant strains, 0.3% showed high-level resistance (MIC > or = 2 mg/l). The rate of resistance to erythromycin (MIC > or = 4 mg/l) was 2.3%, to tetracycline (MIC > or = 8 mg/l) 8.5%, to chloramphenicol (MIC > or = 8 mg/l) 1.0%, and to trimethoprim sulfamethoxazole (MIC > or = 3.2/64 mg/l) 3.3%. Penicillin-resistant strains showed significantly higher resistance to the other antibiotics tested. Resistance to penicillin was higher in isolates from the respiratory tract than in those from blood and cerebrospinal fluid (6.2% vs. 2.4%, respectively). There was no increase in penicillin resistance from 1991 through 1994 (5.3% vs. 4.9%, respectively).

Toxic shock syndrome due to group C streptococci. A case report

BACKGROUND

Streptococcal toxic shock-like syndrome is a life-threatening illness which is on the increase. In early reports, only group A beta-hemolytic streptococcus was associated with the disease, but recent evidence indicates non-A streptococci groups are also involved.

OBSERVATIONS

We describe the first reported case of streptococcal toxic shock-like syndrome caused by a group C strain in Italy. Prior to the disease, the patient, a 46-year-old man, had been in good health and had only a 3-day history of sore throat, low grade fever, vomiting, diarrhea, and myalgia before admission. Initially, diagnosis was based only on clinical evidence: shock, multiorgan failure, profound hypothermia, and no apparent signs of infection. Toxic cardiomyopathy was also present.

RESULTS

Positive throat swab and blood culture confirmed a "definite case" following established criteria. Anamnesis showed a diagnosis of monoclonal gammopathy. Antibiotic treatment was begun immediately on admission of the patient, who was discharged 20 days later in good health.

CONCLUSIONS

This case illustrates how an early diagnosis and prompt antibiotic therapy can determine a more favorable outcome.

Volume of blood required to detect common neonatal pathogens

OBJECTIVE

To determine the minimum volume of blood and the absolute number of organisms required for detection of bacteremia and fungemia by an automated colorimetric blood culture system (BacT/Alert, Organon Teknika).

DESIGN

Common neonatal pathogens, Escherichia coli, Streptococcus agalactiae (group B streptococcus (GBS): one American Type Culture Collection (ATCC) strain and one clinical isolate), Staphylococcus epidermidis, and Candida albicans, were seeded into blood to produce bacteremia or fungemia with low colony counts (1 to 3 colony-forming units (CFU) per milliliter) and ultra-low colony counts (<1 CFU/ml). For each organism, 96 culture bottles were inoculated with either 0.25, 0.5, 1.0, or 4.0 ml of the two seeded blood concentrations. Blood culture bottles were incubated in the BacT/Alert device for 5 days, and time to positivity was noted when applicable. All bottles were subcultured on plated media.

DATA ANALYSIS

The Poisson statistic was used to calculate the probability of finding at least one viable CFU per inoculated culture bottle. The fraction of culture bottles with positive findings per group was divided by the probability of one or more organisms present to give the positivity index.

RESULTS

Plated subculture identified no growth of organisms not detected by the colorimetric detection system. The false-positive rate for the automated device was less than 1%. The positivity index for the GBS clinical isolate was 1.13, for the GBS ATCC isolate 0.96, for S. epidermidis 0.94, for C. albicans 0.97, and for E. coli 0.95. There was a statistically significant difference with time to positivity and inocula volume (p <0.01), but the difference was not clinically important.

CONCLUSIONS

If one or two viable colony-forming units are in the blood inoculated into culture media, the BacT/Alert system will detect growth rapidly. Because there appears to be a sizable subset of neonates who are at risk of sepsis with a colony count less than 4 CFU/ml, then a 0.5 ml inoculum of blood into the culture media is inadequate for sensitive and timely detection of bacteremia. One to two milliliters of blood should increase microorganism recovery in the face of low-colony-count sepsis.

Role of gamma interferon in a neonatal mouse model of group B streptococcal disease

The aim of this study was to assess the role of gamma interferon (IFN-gamma) in a neonatal mouse model of group B streptococcal (GBS) sepsis. IFN-gamma was produced by spleen cells at 24, 48, and 72 h after GBS challenge. Treatment with anti-IFN-gamma at 6 h before challenge totally abrogated the IFN-gamma response but did not affect survival. Subcutaneous administration of recombinant IFN-gamma (2,500 IU per pup) at 18 h after challenge resulted in increased survival time and reduced blood colony counts at 48 and 72 h. In vitro preincubation of neonatal whole blood with IFN-gamma before the addition of GBS resulted in significant restriction of bacterial growth. These data indicate that administration of recombinant IFN-gamma can partially restore impaired host defenses against GBS in neonatal mice. This cytokine may be useful for the treatment of neonatal infections.

[Benign increase of tumor marker Ca 12-5 in pelvic peritonitis with ascites]

Two patients suffering from pelveoperitonitis had ascites and elevated CA 12-5 serum level mimicking epithelial ovarian cancer. Both were treated successfully with antibiotics, after laparoscopic confirmation.

Detection of antibody isotypes to streptolysin O by dot ELISA

The presence of antibody isotypes (IgG, IgA and IgM) to streptolysin O was determined by dot ELISA in 222 serum samples from patients with different levels of anti-streptolysin O (SLO) antibodies as measured by the neutralizing assay (NA), from patients with diseases not related to nonsuppurative complications of Streptococcus pyogenes infection, and from clinically healthy individuals. Immunoglobulin G antibodies were found in 72% of sera from patients with SLO antibodies higher than 333 Todd units (TU), and IgA antibodies were also detected in 53%, but no IgM antibodies were demonstrable. High copositivity (0.94), conegativity (0.97), and positive (0.96) and negative (0.96) predictive values were observed when IgG and IgA findings were combined. The dot ELISA gave highly reproducible results. The present data suggest that the assay may be of practical value for routine detection of SLO antibodies when employed with an anti-human immunoglobulin light chain peroxidase conjugate.