Acute pharyngitis

Improved diagnostic accuracy of group A streptococcal pharyngitis with use of real-time biosurveillance

BACKGROUND

Clinical prediction rules do not incorporate real-time incidence data to adjust estimates of disease risk in symptomatic patients.

OBJECTIVE

To measure the value of integrating local incidence data into a clinical decision rule for diagnosing group A streptococcal (GAS) pharyngitis in patients aged 15 years or older.

DESIGN

Retrospective analysis of clinical and biosurveillance predictors of GAS pharyngitis.

SETTING

Large U.S.-based retail health chain.

PATIENTS

82 062 patient visits for pharyngitis.

MEASUREMENTS

Accuracy of the Centor score was compared with that of a biosurveillance-responsive score, which was essentially an adjusted Centor score based on real-time GAS pharyngitis information from the 14 days before a patient's visit: the recent local proportion positive (RLPP).

RESULTS

Increased RLPP correlated with the likelihood of GAS pharyngitis (r(2) = 0.79; P < 0.001). Local incidence data enhanced diagnostic models. For example, when the RLPP was greater than 0.30, managing patients with Centor scores of 1 as if the scores were 2 would identify 62, 537 previously missed patients annually while misclassifying 18, 446 patients without GAS pharyngitis. Decreasing the score of patients with Centor values of 3 by 1 point for an RLPP less than 0.20 would spare unnecessary antibiotics for 166, 616 patients while missing 18, 812 true-positive cases.

LIMITATIONS

Analyses were conducted retrospectively. Real-time regional data on GAS pharyngitis are generally not yet available to clinicians.

CONCLUSION

Incorporating live biosurveillance data into clinical guidelines for GAS pharyngitis and other communicable diseases should be considered for reducing missed cases when the contemporaneous incidence is elevated and for sparing unnecessary antibiotics when the contemporaneous incidence is low. Delivering epidemiologic data to the point of care will enable the use of real-time pretest probabilities in medical decision making.

Evaluation of short-term clinical efficacy of 3-day therapy with azithromycin in comparison with 5-day cefcapene-pivoxyl for acute streptococcal tonsillopharyngitis in primary care

Group A streptococcal (GAS) tonsillopharyngitis is one of the few conditions for which antibiotics are advocated among common upper respiratory infections. Although a 3-day course of azithromycin is attracting attention as a treatment of choice for the condition, it is not clear if the efficacy of the treatment is comparable with that of treatment with cephalosporins. A prospective, randomized, comparative multicenter study was conducted to compare the efficacy of azithromycin (AZM) given once daily for 3 days with that of cefcapene-pivoxyl (CFPN-PI) divided into three daily doses for 5 days. 88 patients (male: 38, mean age: 16.5) were treated with AZM and 69 (male: 34, mean age: 16.9) with CFPN-PI. The symptoms of all but 5 (2 for AZM and 3 for CFPN-PI) of the patients were resolved by the 8th day of the treatment. By the 4th day of the treatment, criteria for clinical efficacy were fulfilled in 71 (80.7%) subjects who were treated with AZM and in 48 (67.6%) of those treated with CFPN-PI (p = 0.07). The same figures on the 8th day of the treatment were 86 (97.7%) and 68 (95.8%), respectively (p = 0.66), confirming there was no significant difference in clinical efficacy between the two treatments. Mild adverse reactions were reported by two patients treated with AZM and by none treated with CFPN-PI. The clinical efficacy of a 3-day course with AZM was comparable with that of a 5-day course of CFPN-PI for GAS tonsillopharyngitis.

Analysis of group A Streptococcus gene expression in humans with pharyngitis using a microarray

Pharyngitis caused by group A streptococci (GAS) is one of the most common infections around the world. However, relatively little is known about which genes are expressed and which genes regulate expression during acute infection. Due to their ability to provide genome-wide views of gene expression at one time, microarrays are increasingly being incorporated in GAS research. In this study, a novel electrochemical detection-based microarray was used to identify gene expression patterns among humans with culture-confirmed GAS pharyngitis. Using 14 samples (11 GAS-positive and three GAS-negative) obtained from subjects seen at the Brooke Army Medical Center paediatric clinic, this study demonstrated two different clusters of gene expression patterns. One cluster expressed a larger number of genes related to phages, immune-system evasion and survival among competing oral flora, signifying a potentially more virulent pattern of gene expression. The other cluster showed a greater number of genes related to nutrient acquisition and protein expression. This in vivo genome-wide analysis of GAS gene expression in humans with pharyngitis evaluated global gene expression in terms of virulence factors.

A comparison between the Strep A Rapid Test Device and conventional culture for the diagnosis of streptococcal pharyngitis

BACKGROUND

Rapid antigen detection tests are frequently used to diagnose pharyngitis due to Streptococcus pyogenes. Because a large number of kits are available commercially, performance characteristics may vary considerably. The present study evaluated one such kit currently in use in Canadian laboratories for which published evaluations are not available.

OBJECTIVE

To evaluate the performance characteristics of the Strep A Rapid Test Device (SARTD) (Nova Century Scientific Inc, Canada).

METHODS

Pharyngeal swabs from 818 patients with suspected streptococcal pharyngitis were tested. Swabs were initially inoculated onto the surface of a blood agar plate and then used to perform the rapid antigen test. The test was performed in accordance with the product monograph. Beta-hemolytic colonies were identified as S pyogenes using conventional means.

RESULTS

Four hundred ninety specimens were obtained from children and 328 from adults. S pyogenes was recovered from 171 (21%) patients. The SARTD detected S pyogenes antigens in 123 of 171 specimens from which S pyogenes was isolated on culture; the screen was negative in 610 of 647 specimens from which cultures were negative. The positive and negative predictive values of the SARTD were 76.9% and 92.7%, respectively.

CONCLUSIONS

The SARTD was much less sensitive (72%) than was suggested in the product monograph (90%). Laboratories should vigorously evaluate such products in-house, optimize specimen collection and transport, and choose more sensitive kits for use.

Predicting streptococcal pharyngitis in adults in primary care: a systematic review of the diagnostic accuracy of symptoms and signs and validation of the Centor score

BACKGROUND

Stratifying patients with a sore throat into the probability of having an underlying bacterial or viral cause may be helpful in targeting antibiotic treatment. We sought to assess the diagnostic accuracy of signs and symptoms and validate a clinical prediction rule (CPR), the Centor score, for predicting group A β-haemolytic streptococcal (GABHS) pharyngitis in adults (> 14 years of age) presenting with sore throat symptoms.

METHODS

A systematic literature search was performed up to July 2010. Studies that assessed the diagnostic accuracy of signs and symptoms and/or validated the Centor score were included. For the analysis of the diagnostic accuracy of signs and symptoms and the Centor score, studies were combined using a bivariate random effects model, while for the calibration analysis of the Centor score, a random effects model was used.

RESULTS

A total of 21 studies incorporating 4,839 patients were included in the meta-analysis on diagnostic accuracy of signs and symptoms. The results were heterogeneous and suggest that individual signs and symptoms generate only small shifts in post-test probability (range positive likelihood ratio (+LR) 1.45-2.33, -LR 0.54-0.72). As a decision rule for considering antibiotic prescribing (score ≥ 3), the Centor score has reasonable specificity (0.82, 95% CI 0.72 to 0.88) and a post-test probability of 12% to 40% based on a prior prevalence of 5% to 20%. Pooled calibration shows no significant difference between the numbers of patients predicted and observed to have GABHS pharyngitis across strata of Centor score (0-1 risk ratio (RR) 0.72, 95% CI 0.49 to 1.06; 2-3 RR 0.93, 95% CI 0.73 to 1.17; 4 RR 1.14, 95% CI 0.95 to 1.37).

CONCLUSIONS

Individual signs and symptoms are not powerful enough to discriminate GABHS pharyngitis from other types of sore throat. The Centor score is a well calibrated CPR for estimating the probability of GABHS pharyngitis. The Centor score can enhance appropriate prescribing of antibiotics, but should be used with caution in low prevalence settings of GABHS pharyngitis such as primary care.

Dispersal of Group A streptococcal biofilms by the cysteine protease SpeB leads to increased disease severity in a murine model

Group A Streptococcus (GAS) is a Gram-positive human pathogen best known for causing pharyngeal and mild skin infections. However, in the 1980's there was an increase in severe GAS infections including cellulitis and deeper tissue infections like necrotizing fasciitis. Particularly striking about this elevation in the incidence of severe disease was that those most often affected were previously healthy individuals. Several groups have shown that changes in gene content or regulation, as with proteases, may contribute to severe disease; yet strains harboring these proteases continue to cause mild disease as well. We and others have shown that group A streptococci (MGAS5005) reside within biofilms both in vitro and in vivo. That is to say that the organism colonizes a host surface and forms a 3-dimensional community encased in a protective matrix of extracellular protein, DNA and polysaccharide(s). However, the mechanism of assembly or dispersal of these structures is unclear, as is the relationship of these structures to disease outcome. Recently we reported that allelic replacement of the streptococcal regulator srv resulted in constitutive production of the streptococcal cysteine protease SpeB. We further showed that the constitutive production of SpeB significantly decreased MGAS5005Δsrv biofilm formation in vitro. Here we show that mice infected with MGAS5005Δsrv had significantly larger lesion development than wild-type infected animals. Histopathology, Gram-staining and immunofluorescence link the increased lesion development with lack of disease containment, lack of biofilm formation, and readily detectable levels of SpeB in the tissue. Treatment of MGAS5005Δsrv infected lesions with a chemical inhibitor of SpeB significantly reduced lesion formation and disease spread to wild-type levels. Furthermore, inactivation of speB in the MGAS5005Δsrv background reduced lesion formation to wild-type levels. Taken together, these data suggest a mechanism by which GAS disease may transition from mild to severe through the Srv mediated dispersal of GAS biofilms.

Update on the management of acute pharyngitis in children

Streptococcal pharyngitis is a very common pathology in paediatric age all over the world. Nevertheless there isn't a joint agreement on the management of this condition. Some authors recommend to perform a microbiological investigation in suspected bacterial cases in order to treat the confirmed cases with antibiotics so to prevent suppurative complications and acute rheumatic fever. Differently, other authors consider pharyngitis, even streptococcal one, a benign, self-limiting disease. Consequently they wouldn't routinely perform microbiological tests and, pointing to a judicious use of antibiotics, they would reserve antimicrobial treatment to well-selected cases. It has been calculated that the number of patients needed to treat to prevent one complication after upper respiratory tract infections (including sore throat), was over 4000. Even the use of the Centor score, in order to evaluate the risk of streptococcal infection, is under debate and the interpretation of the test results may vary considerably. Penicillin is considered all over the world as first line treatment, but oral amoxicillin is also accepted and, due to its better palatability, can be a suitable option. Macrolides should be reserved to the rare cases of proved allergy to β-lactams. Cephalosporins can be used in patients allergic to penicillin (with the exception of type I hypersensibility) and have been also proposed to treat the relapses.

Decreasing incidence of adenotonsillar problems in Dutch general practice: real or artefact?

BACKGROUND

The incidence of hypertrophy and recurrent infections of the tonsils/adenoids appears to be decreasing in the Netherlands. It is uncertain whether this is a 'real' decrease in the incidence of disease or an 'artefact'.

AIM

To investigate possible causes of the decreasing incidence of adenotonsillar problems among Dutch children.

DESIGN OF STUDY

Observational.

SETTING

A nationally representative general practice database.

METHOD

Incidence rates were calculated over 2002-2005 among children aged 0-14 years. Multilevel Poisson regression analyses were used to examine the following possible causes of changing incidence rates: change in recording (more substitution codes), change in the demand for care (fewer visits to the GP), and change in the supply of care (fewer antibiotic prescriptions and referrals). Indications for a 'real' change in the incidence of disease were examined by calculating incidence rates of other clinical manifestations of microbial pathogens that may cause adenotonsillar problems.

RESULTS

The incidence rate decreased significantly (P = 0.017) from 3.0 to 1.3 per 1000 children per year. Correcting for demand for and supply of care led to a smaller decline in yearly incidence, from 2.9 to 1.7 per 1000 children per year (P = 0.105). No clearly similar trend was found in other clinical manifestations of viruses and bacteria that may cause adenotonsillar problems.

CONCLUSION

Part of the declining trend can be explained by a change in the demand for and supply of care, but no apparent causal clue emerged for the residual declining trend in the incidence of disease.

The patient with sore throat

Sore throat is a common medical complaint seen by the emergency practitioner, internist, pediatrician, and otolaryngologist. The differential for sore throat is vast. However, with a directed history this can often be narrowed down to 2 to 3 possible diagnoses. By paying particular attention to the associated symptoms and duration of symptoms, common self-limited etiologies like viral pharyngitis and nonstreptococcal tonsillitis can be distinguished from those that require more investigation, such as supraglottitis and tonsillar cancer. A sore throat is most commonly caused by an infectious, inflammatory, or neoplastic etiologic factor.

Effectiveness of corticosteroid treatment in acute pharyngitis: a systematic review of the literature

OBJECTIVES

The objective was to examine the effectiveness of corticosteroid treatment for the relief of pain associated with acute pharyngitis potentially caused by group A beta-hemolytic Streptococcus (GABHS).

METHODS

This was a systematic review of the literature. Data sources used were electronic databases (Cochrane Library, MEDLINE, EMBASE, Biosis Previews, Scopus, and Web of Science), controlled trial registration websites, conference proceedings, study references, experts in the field, and correspondence with authors. Selection criteria consisted of randomized controlled trials (RCTs) in which corticosteroids, alone or in combination with antibiotics, were compared to placebo or any other standard therapy for treatment of acute pharyngitis in adult patients, pediatric patients, or both. Two reviewers independently assessed for relevance, inclusion, and study quality. Weighted mean differences (WMDs) were calculated and are reported with corresponding 95% confidence intervals (CIs).

RESULTS

From 272 potentially relevant citations, 10 studies met the inclusion criteria. When compared to placebo, corticosteroids reduced the time to clinically meaningful pain relief (WMD = -4.54 hours; 95% CI = -7.19 to -1.89); however, they provided only a small reduction in pain scores at 24 hours (WMD = -0.90 on a 0-10 visual analog scale; 95% CI = -1.5 to -0.3). Heterogeneity among pooled studies was identified for both outcomes (I(2) = 81 and 74%, respectively); however, the GABHS-positive subgroup receiving corticosteroid treatment did have a significant mean reduction in time to clinically meaningful pain relief of 5.22 hours (95% CI = -7.02 to -3.42; I(2) = 0%). Short-term side effect profiles between corticosteroids and placebo groups were similar.

CONCLUSIONS

Corticosteroid administration for acute pharyngitis was associated with a relatively small effect in time to clinically meaningful pain relief (4.5-hour reduction) and in pain relief at 24 hours (0.9-point reduction), with significant heterogeneity in the pooled results. Decision-making should be individualized to determine the risks and benefits; however, corticosteroids should not be used as routine treatment for acute pharyngitis.

Haemophilus influenzae and Haemophilus haemolyticus in tonsillar cultures of adults with acute pharyngotonsillitis

OBJECTIVE

The aim of this study was to evaluate the clinical implication of Haemophilus haemolyticus, one of the closest relative of Haemophilus influenzae, on acute pharyngotonsillitis.

METHODS

We applied polymerase chain reaction (PCR) for 16S ribosomal DNA (rDNA) and IgA protease gene (iga) to distinguish H. haemolyticus and H. influenzae.

RESULTS

Among the 199 Haemophilus spp. isolated from 214 patients with acute pharyngotonsillitis, 52 (24.3%) H. influenzae strains and 23 (10.7%) H. haemolyticus strains were identified by polymerase chain reaction (PCR) for 16S rDNA and IgA protease gene (iga). All H. haemolyticus strains showed hemolysis on horse blood agar and there were no other Haemophilus spp., nonhemolytic H. haemolyticus and H. influenzae variant strains that had absent iga gene. H. hemolyticus showed close genetic relationship with H. influenzae evaluated by pulsed field gel electrophoresis (PFGE). The cases of acute pharyngotonsillitis showing WBC=7000/mm(3) or CRP=8 mg/dl were frequently found among cases with H. influenzae rather than cases with H. haemolyticus.

CONCLUSION

H. haemolyticus is a pharyngeal commensal that is isolated frequently from adults with acute pharyngotonsillitis.

Sensitivity and Specificity of Rapid Antigen Detection Testing for Diagnosing Pharyngitis in the Emergency Department

Acute pharyngitis in adults is primarily a viral infection; only about 10% of cases are of bacterial etiology. Most cases of bacterial pharyngitis are caused by group A beta-hemolytic streptococci (GABHS). One laboratory method for the diagnosis of GABHS is rapid antigen diagnostic testing (RADT), which can be processed during an emergency department visit and which has become a popular alternative to throat swab cultures. We conducted a study to define the sensitivity and specificity of RADT, using throat culture results as the gold standard, in 100 emergency department patients who presented with symptoms consistent with streptococcal pharyngitis. We found that RADT had a sensitivity of 68.2% (15 of 22), a specificity of 89.7% (70 of 78), a positive predictive value of 65.2% (15 of 23), and a negative predictive value of 90.9% (70 of 77). We conclude that RADT is useful in the emergency department when the clinical suspicion is GABHS, but results should be confirmed with a throat culture in patients whose RADT results are negative.

Herpes simplex virus infection in a university health population: clinical manifestations, epidemiology, and implications

OBJECTIVE

The authors described clinical presentations of oral and genital herpes simplex virus (HSV) infections in a university health population and implications of these findings.

PARTICIPANTS AND METHODS

Using a standardized data collection tool, 215 records of patients with symptomatic culture-positive HSV infections were reviewed.

RESULTS

HSV-1 accounted for 78% of female and 85% of male genital herpes (GH) infections, and oral herpes (OH) infections presented as an acute febrile illness (AFI) in 51% of those 18 to 24 years old. HSV-2 accounted for 68% of GH infections among adults 25 or older.

CONCLUSIONS

As seroprevalence for both HSV-1 and HSV-2 in the United States is decreasing, a growing college age cohort is at risk for primary HSV-1 infection. The proportion of GH caused by HSV-1 also continues to increase. This understanding has implications for clinical care, sexual health programming, and counseling strategies.

Comparative Study of 5-Day and 10-Day Cefditoren Pivoxil Treatments for Recurrent Group A beta-Hemolytic Streptococcus pharyngitis in Children

Efficacy of short-course therapy with cephalosporins for treatment of group A beta-hemolytic streptococcus (GABHS) pharyngitis is still controversial. Subjects were 226 children with a history of at least one episode of GABHS pharyngitis. Recurrence within the follow-up period (3 weeks after initiation of therapy) occurred in 7 of the 77 children in the 5-day treatment group and in 1 of the 149 children in the 10-day treatment group; the incidence of recurrence being significantly higher in the 5-day treatment group. Bacteriologic treatment failure (GABHS isolation without overt pharyngitis) at follow-up culture was observed in 7 of the 77 children in the 5-day treatment group and 17 of the 149 children in the 10-day treatment group. There was no statistical difference between the two groups. A 5-day course of oral cephalosporins is not always recommended for treatment of GABHS pharyngitis in children who have repeated episodes of pharyngitis.

In vitro evaluation of five rapid antigen detection tests for group A beta-haemolytic streptococcal sore throat infections

BACKGROUND

Using accurate and easy to use rapid antigen detection tests (RADTs) to identify group A beta-haemolytic Streptococci (GABHS) sore throat infections could reduce unnecessary antibiotic prescribing and antimicrobial resistance. Although there is no international consensus on the use of RADTs, these kits have been widely adopted in Finland, France and the USA. Yet in the UK, the Clinical Knowledge Summaries, that provide the main online guidance for GPs, discourage RADTs use, citing their poor sensitivity and inability to impact on prescribing decisions in acute sore throat infections.

OBJECTIVE

The purpose of this study was to evaluate the ease of use and in vitro accuracy (sensitivity and specificity) of the five most commonly used RADTs in Europe (OSOM Ultra, Quickvue Dipstick, Streptatest, Clearview Exact Strep A and IMI Test Pack).

METHODS

To ensure the RADTs were evaluated objectively, a standardized in vitro method using known concentrations of GABHS was used to remove the inherent biases associated with clinical studies.

RESULTS

The IMI Test Pack was the easiest RADT to use overall. The ability to detect all positive GABHS (sensitivity) varied considerably between kits from 95% [95% confidence interval (CI): 88-98%], for the IMI Test Pack and OSOM, to 62% (95% CI: 51-72%) for Clearview, at the highest GABHS concentration. None of the RADTs gave any false-positive results with commensal flora-they were 100% specific.

CONCLUSIONS

The IMI Test Pack is most suitable for use in primary care, as it had high sensitivity, high specificity and was easy to use.

Infectious disease and boxing

There are no unique boxing diseases but certain factors contributing to the spread of illnesses apply strongly to the boxer, coach, and the training facility. This article examines the nature of the sport of boxing and its surrounding environment, and the likelihood of spread of infection through airborne, contact, or blood-borne routes of transmission. Evidence from other sports such as running, wrestling, and martial arts is included to help elucidate the pathophysiologic elements that could be identified in boxers.

Infectious mononucleosis with secondary cold agglutinin disease causing autoimmune haemolytic anaemia

This case report describes a 20-year-old woman whose initial clinical, laboratory, and radiological presentation suggested obstructive jaundice. However, she was subsequently found to be suffering from autoimmune haemolytic anaemia resulting from an Epstein-Barr virus infection complicated by cold agglutinin disease. The patient went on to make a complete clinical recovery after discharge.

Corticosteroids for pain relief in sore throat: systematic review and meta-analysis

OBJECTIVE

To evaluate whether systemic corticosteroids improve symptoms of sore throat in adults and children.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Cochrane Central, Medline, Embase, Database of Reviews of Effectiveness (DARE), NHS Health Economics Database, and bibliographies.

OUTCOME MEASURES

Percentage of patients with complete resolution at 24 and 48 hours, mean time to onset of pain relief, mean time to complete resolution of symptoms, days missed from work or school, recurrence, and adverse events.

RESULTS

We included eight trials, consisting of 743 patients in total (369 children, 374 adults). 348 (47%) had exudative sore throat, and 330 (44%) were positive for group A beta-haemolytic streptococcus. In addition to antibiotics and analgesia, corticosteroids significantly increased the likelihood of complete resolution of pain at 24 hours (four trials) by more than three times (relative risk 3.2, 95% confidence interval 2.0 to 5.1), and at 48 hours (three trials) to a lesser extent (1.7, 1.3 to 2.1). Corticosteroids (six trials) reduced mean time to onset of pain relief by more than 6 hours (95% confidence interval 3.4 to 9.3, P<0.001), although significant heterogeneity was present. The mean time to complete resolution was inconsistent across trials and a pooled analysis was not undertaken. Reporting of other outcomes was limited.

CONCLUSIONS

Corticosteroids provide symptomatic relief of pain in sore throat, in addition to antibiotic therapy, mainly in participants with severe or exudative sore throat.

Prospective surveillance of streptococcal sore throat in a tropical country

BACKGROUND

Acute rheumatic fever and rheumatic heart disease cause a high burden of disease in Fiji and surrounding Pacific Island countries, but little is known about the epidemiology of group A streptococcal (GAS) pharyngitis in the region. We designed a study to estimate the prevalence of carriage of beta-hemolytic streptococci (BHS) and the incidence of BHS culture-positive sore throat in school aged children in Fiji.

METHODS

We conducted twice-weekly prospective surveillance of school children aged 5 to 14 years in 4 schools in Fiji during a 9-month period in 2006, after an initial phase of pharyngeal swabbing to determine the prevalence of BHS carriage.

RESULTS

We enrolled 685 children. The prevalence of GAS carriage was 6.0%, while the prevalence of group C streptococcal (GCS) and group G streptococcal (GGS) carriage was 6.9% and 12%, respectively. There were 61 episodes of GAS culture-positive sore throat during the study period equating to an incidence of 14.7 cases per 100 child-years (95% CI, 11.2-18.8). The incidence of GCS/GGS culture-positive sore throat was 28.8 cases per 100 child-years (95% CI, 23.9-34.5). The clinical nature of GAS culture-positive sore throat was more severe than culture-negative sore throat, but overall was mild compared with that found in previous studies. Of the 101 GAS isolates that emm sequence typed there were 45 emm types with no dominant types. There were very few emm types commonly encountered in industrialized nations and only 9 of the 45 emm types found in this study are emm types included in the 26-valent GAS vaccine undergoing clinical trials.

CONCLUSIONS

GAS culture-positive sore throat was more common than expected. Group C and group G streptococci were frequently isolated in throat cultures, although their contribution to pharyngeal infection is not clear. The molecular epidemiology of pharyngeal GAS in our study differed greatly from that in industrialized nations and this has implications for GAS vaccine clinical research in Fiji and other tropical developing countries.

SpeB of Streptococcus pyogenes differentially modulates antibacterial and receptor activating properties of human chemokines

Background

CXC chemokines are induced by inflammatory stimuli in epithelial cells and some, like MIG/CXCL9, IP–10/CXCL10 and I–TAC/CXCL11, are antibacterial for Streptococcus pyogenes.

Methodology/Principal Findings

SpeB from S. pyogenes degrades a wide range of chemokines (i.e. IP10/CXCL10, I-TAC/CXCL11, PF4/CXCL4, GROα/CXCL1, GROβ/CXCL2, GROγ/CXCL3, ENA78/CXCL5, GCP-2/CXCL6, NAP-2/CXCL7, SDF-1/CXCL12, BCA-1/CXCL13, BRAK/CXCL14, SRPSOX/CXCL16, MIP-3α/CCL20, Lymphotactin/XCL1, and Fractalkine/CX3CL1), has no activity on IL-8/CXCL8 and RANTES/CCL5, partly degrades SRPSOX/CXCL16 and MIP-3α/CCL20, and releases a 6 kDa CXCL9 fragment. CXCL10 and CXCL11 loose receptor activating and antibacterial activities, while the CXCL9 fragment does not activate the receptor CXCR3 but retains its antibacterial activity.

Conclusions/Significance

SpeB destroys most of the signaling and antibacterial properties of chemokines expressed by an inflamed epithelium. The exception is CXCL9 that preserves its antibacterial activity after hydrolysis, emphasizing its role as a major antimicrobial on inflamed epithelium.

Antibacterial activity of cefditoren against major community-acquired respiratory pathogens recently isolated in Italy

In this study we evaluated the in vitro activities of cefditoren--a broad-spectrum oral cephalosporin--and other comparator agents against 2,396 fresh isolates from community-acquired respiratory tract infections, collected from 6 clinical Italian microbiology laboratories. On penicillin-susceptible pneumococci and Streptococcus pyogenes, cefditoren demonstrated to be the most active antibiotic (MIC(90)values of 0.03 and 0.06 mg/L respectively), showing only a slight decrease in potency on penicillin-intermediate and resistant pneumococci (MIC(90)value 0.5 mg/L, 1.0 mg/L respectively). All the other comparators displayed MIC(90 )values of 4 - 8 mg/L for penicillins and of 4 to >64 mg/L for the oral cephalosporins. Cefditoren and levofloxacin were the most active against MSSA (MIC(90)0.5 mg/mL). Cefditoren displayed a uniformly potent inhibitory activity (MIC(90)of 0.03 mg/L) against all strains of Haemophilus influenzae, regardless of their ampicillin resistance (mediated or not by beta-lactamase production), while against Moraxella catarrhalis MIC(90)values were higher against beta-lactamase-positive (0.25 mg/L). Cefditoren was active also against Klebsiella pneumoniae and Escherichia coli : in this case its activity was comparable with that of levofloxacin. In conclusion, cefditoren, due to its potent activity, is a new effective therapeutic option for the treatment of respiratory tract infections.

Pharyngotonsillitis in children: view from a sample of pediatricians and otorhinolaryngologists

Acute pharyngotonsillitis is a common upper airway infection in children.

AIM

To analyze opinions and practices of pediatricians and otorhinolaryngologists from Sao Paulo State, Brazil, concerning diagnosis, treatment and prevention of pharyngotonsillitis and their complications in children.

METHODS

We randomly selected 1,370 pediatricians and 1,000 otolaryngologists from Sao Paulo State, Brazil. A questionnaire was mailed to the specialists.

STUDY DESIGN

Cross-sectional.

RESULTS

95.8% of the pediatricians and 91.5% of the otolaryngologists do not perform routine laboratory diagnosis for acute pharyngotonsillitis in children. The antimicrobials more commonly prescribed by pediatricians for treatment of bacterial pharyngotonsillitis were: oral penicillin for 10 days (33.6%) and s single injection of benzathine penicillin G (19.7%). The antimicrobials prescribed more often by otorhinolaryngologists for treatment were: oral penicillin for 10 days (35.4%) and oral penicillin for 7 days (25.7%). Tonsillectomy was considered the most effective measure for prevention of bacterial pharyngotonsillitis by more than half of pediatricians and otolaryngologists. Repeated pharyngotonsillitis was the main reason for otolaryngologists to indicate tonsillectomy for school-aged children and adolescents (49.3% and 53.4% respectively).

CONCLUSIONS

It is necessary to standardize the practices of pediatricians and otolaryngologists regarding diagnosis and treatment of pharyngotonsillitis in children.

A scoring system for management of acute pharyngo-tonsillitis in adults

Objectives

The aim of this study was to develop and evaluate a scoring system for the management of acute pharyngo-tonsillitis.

Methods

We conducted a prospective study between May 2004 and June 2005. Patients with acute pharyngo-tonsillitis were evaluated for causative pathogens and were assessed clinical symptoms and pharyngo-tonsillar finding by a clinical scoring system.

Results

A total 214 adult patients were enrolled in this study. Streptococcus pyogenes were identified at 13.6%. Thirty-one viruses were also identified by PCR. They were adenovirus (4.8%), influenza virus (1.0%), RS virus (6.3%), and human metapneumovirus (2.9%). Numbers of total white blood cells and levels of C-reactive protein showed a significant positive correlation with clinical scores (p < 0.001) and were also higher in cases with S. pyogenes. The clinical scores rapidly improved after the antimicrobial treatments in moderate cases and severe cases.

Conclusion

The current study strongly suggested that the clinical scoring system reflected disease severity well and would be very useful for evaluating clinical course and decision making for the antimicrobial treatment of acute pharyngo-tonisllitis.

Economic burden of adult pharyngitis: the payer's perspective

OBJECTIVES

Although not recommended by practice guidelines, physicians frequently prescribe an antibiotic for adults with viral pharyngitis. The financial burden of this practice, from the payer's perspective, has not been previously evaluated. The purpose of this study was to estimate those expenditures.

METHODS

A cost-of-illness study was performed to estimate annual expenditures of pharyngitis management from the payer's perspective. National Ambulatory Care Survey data were used to represent current patterns of ambulatory care visits and antibiotic prescriptions for adult pharyngitis. Direct and antibiotic resistance costs were summed to estimate total expenditures for pharyngitis management. Resistance costs were calculated using a model linking the effect of antibiotic consumption to the cost consequences of resistant Streptococcus pneumoniae infection. Sensitivity analyses compared cost outcomes of current practice, adherence to pharyngitis management guidelines from the Infectious Diseases Society of America (IDSA), and nonantibiotic treatment.

RESULTS

In the base-case analysis, reflecting current practice patterns, total expenditures were $1.2 billion with antibiotic resistance contributing 36% ($426 million). IDSA guideline adherence decreased costs to $559 million with resistance accounting for 6.8% ($37.9 million). Guideline adherence plus reducing office visits by 30% decreased costs to $372 million, with only 1.4% ($5.3 million) due to resistance. Additional cost-savings of $88 million were realized by using a nonantibiotic treatment strategy.

CONCLUSIONS

Current practice imposed a substantial economic burden on the payer, while guideline adherence resulted in cost reductions, especially in terms of resistance, emphasizing that antibiotic prescribing habits have broad economic consequences. Relevant stakeholders, payers, physicians, and other health-care providers should revisit efforts to encourage adherence to pharyngitis guidelines to reduce health-care costs.

PDIA3, HSPA5 and vimentin, proteins identified by 2-DE in the valvular tissue, are the target antigens of peripheral and heart infiltrating T cells from chronic rheumatic heart disease patients

Rheumatic fever (RF) is a post-infectious autoimmune disease due to sequel of group A streptococcus (GAS) pharyngitis. Rheumatic heart disease (RHD), the major manifestation of RF, is characterized by inflammation of heart valves and myocardium. Molecular mimicry between GAS antigens and host proteins has been shown at B and T cell level. However the identification of the autoantigens recognized by B and T cells within the inflammatory microenvironment of heart tissue in patients with RHD is still incompletely elucidated. In the present study, we used two-dimensional gel electrophoresis (2-DE) and mass spectrometry to identify valvular tissue proteins target of T cells from chronic RHD patients. We could identify three proteins recognized by heart infiltrating and peripheral T cells as protein disulfide isomerase ER-60 precursor (PDIA3), 78kD glucose-regulated protein precursor (HSPA5) and vimentin, with coverage of 45%, 43 and 34%, respectively. These proteins were recognized in a proliferation assay by peripheral and heart infiltrating T cells from RHD patients suggesting that they may be involved in the autoimmune reactions that leads to valve damage. We also observed that several other proteins isolated by 2-DE but not identified by mass spectrometry were also recognized by T cells. The identified cardiac proteins are likely relevant antigens involved in T cell-mediated autoimmune responses in RF/RHD that may contribute to the development of RHD.

The intrinsic immunoglobulin g endopeptidase activity of streptococcal Mac-2 proteins implies a unique role for the enzymatically impaired Mac-2 protein of M28 serotype strains

IdeS, a secreted cysteine protease of the important human pathogen Streptococcus pyogenes, interferes with phagocytic killing by specifically cleaving the heavy chain of immunoglobulin G (IgG). Two allelic variants of the enzyme have been described, the IgG-specific endopeptidase, IdeS (or Mac-1) and Mac-2, a protein with only weak IgG endopeptidase activity, which has been suggested to interfere with opsonophagocytosis by blocking Fcgamma receptors of phagocytic cells. However, despite the fact that Mac-2 proteins interact with Fcgamma receptors, no inhibition of reactive oxygen species (ROS) production, opsonophagocytosis, or streptococcal killing by Mac-2 has been reported. In the present study, Mac-2 proteins are shown to contain IgG endopeptidase activity indistinguishable from the enzymatic activity exhibited by IdeS/Mac-1 proteins. The earlier reported weak IgG endopeptidase activity appears to be unique to Mac-2 of M28 serotype strains (Mac-2(M28)) and is most likely due to the formation of a disulfide bond between the catalytic site cysteine and a cysteine residue in position 257 of Mac-2(M28). Furthermore, Mac-2 proteins are shown to inhibit ROS production ex vivo, independently of the IgG endopeptidase activity of the proteins. Inhibition of ROS generation per se, however, was not sufficient to mediate streptococcal survival in bactericidal assays. Thus, in contrast to earlier studies, implicating separate functions for IdeS and Mac-2 protein variants, the current study suggests that Mac-2 and IdeS are bifunctional proteins, combining Fcgamma receptor binding and IgG endopeptidase activity. This finding implies a unique role for Mac-2 proteins of the M28 serotype, since this serotype has evolved and retained a Mac-2 protein lacking IgG endopeptidase activity.

Current status of group A streptococcal vaccine development

We now have a much more detailed understanding of the molecular pathogenesis of GAS infections. These discoveries have led to the identification of several vaccine candidates which are in various stages of development. One of the leading candidate antigens is the surface M protein, which confers protection against infection in animal models. In addition, M antibodies in human serum correlate with protection against infection with the homologous serotype of GAS. Molecular techniques have been used to genetically engineer highly complex multivalent M protein-based vaccines that appear to be free of potentially harmful tissue crossreactive epitopes. A 26-valent vaccine has been shown to be well-tolerated and immunogenic in adult volunteers and is now being considered for pediatric trials, which is the primary target group for the vaccine. Ongoing efforts are now addressing the epidemiology of GAS infections in developing countries so that new vaccines can be designed to prevent the infections that may trigger ARF and RHD. Successful deployment of safe and effective vaccines to prevent GAS infections and their complications could potentially have a significant impact on the health of millions of people around the world.

Quality of care in the retail health care setting using national clinical guidelines for acute pharyngitis

Rates of adherence to an acute pharyngitis practice guideline in the retail clinic setting were measured as an indicator of clinical quality. An analysis of 57,331 patient visits for the evaluation of acute pharyngitis was conducted. In 39,530 patients with a negative rapid strep test result, nurse practitioner and physician assistant staff adhered to guidelines in 99.05% of cases by withholding unnecessary antibiotics. Of 13,471 patients with a positive rapid strep test result, 99.75% received an appropriate antibiotic prescription. The combined guideline adherence rate for groups with positive and negative rapid strep test results was 99.15%. Strep cultures were performed on 99.1% of patients with a negative rapid strep test result, and 96.2% of patients with a positive culture were treated with an antibiotic. Finally, 0.95% of patients with a negative rapid strep test result were provided an antibiotic outside clinical guidelines; however, approximately half of these prescriptions (n = 190) were supported by documentation of clinical concerns for which an antibiotic was a reasonable choice.

Diagnostic evaluation of mononucleosis-like illnesses

Clinicians face a diagnostic challenge when a patient with the classic fever, pharyngitis, and lymphadenopathy triad of infectious mononucleosis has a negative "spot" heterophile antibody test. This screening test, although commonly considered sensitive for the presence of Epstein-Barr virus (EBV) infection, may be negative early after infection. A growing number of pathogens have been reported to cause heterophile-negative mononucleosis-like illnesses, including cytomegalovirus (CMV), human herpesvirus 6 (HHV-6), human immunodeficiency virus (HIV), adenovirus, herpes simplex virus (HSV), Streptococcus pyogenes, and Toxoplasma gondii. Other infectious and noninfectious disorders also may present in ways that mimic mononucleosis, but fail to generate EBV's archetypal triad of clinical findings. A systematic approach to the diagnosis of mononucleosis-like illnesses ensures that conditions warranting specific therapy are distinguished from others requiring only supportive care.

Microbiologic investigations for head and neck infections

A variety of methods, including direct examination of stained smears, antigen detection, routine and special cultures, and histopathologic evaluation are available for investigation of head and neck infections. Newer rapid molecular techniques with increased sensitivity and specificity are becoming available at many centers. Evaluation of specific causes in head and neck infections is complicated by the tendency for polymicrobial infections, difficulty in obtaining adequate specimens, and the presence of a diverse endogenous microflora at various mucosal sites that also can include true pathogens. These aspects of laboratory investigation for head and neck infections are reviewed in this article.

New understanding of the group A Streptococcus pathogenesis cycle

Group A Streptococcus (GAS) has long been recognized as a human pathogen causing an exceptionally broad range of infections. Despite intense research, however, the molecular mechanisms of GAS disease remain unclear. Recently, many important discoveries have been made that shed light on GAS pathogenesis and open exciting avenues for future research. Advances in genome sequencing, microarray technology and proteomic analysis, in combination with the development of more suitable animal models, have markedly increased our knowledge of the mechanisms underlying GAS pathogenesis. The information gained from these studies will translate into improved diagnostics and new targets for therapeutic drugs and vaccines.

Tonsillectomy versus watchful waiting in recurrent streptococcal pharyngitis in adults: randomised controlled trial

OBJECTIVE

To determine the short term efficacy and safety of tonsillectomy for recurrent streptococcal pharyngitis in adults. Design Randomised controlled trial.

SETTING

Academic referral centre in Finland.

PARTICIPANTS

70 adults with documented recurrent episodes of streptococcal group A pharyngitis.

INTERVENTION

Instant tonsillectomy (n=36) or remaining on waiting list as control (n=34).

MAIN OUTCOME MEASURES

Percentage change in the risk of an episode of streptococcal pharyngitis at 90 days. Rates of all episodes of pharyngitis and days with symptoms and adverse effects.

RESULTS

The mean (SD) follow-up was 164 (63) days in the control group and 170 (12) days in the tonsillectomy group. At 90 days, streptococcal pharyngitis had recurred in 24% (8/34) in the control group and 3% (1/36) in the tonsillectomy group (difference 21%; 95% confidence interval 6% to 36%). The number needed to undergo tonsillectomy to prevent one recurrence was 5 (3 to 16). During the whole follow-up, the rates of other episodes of pharyngitis and days with throat pain and fever were significantly lower in the tonsillectomy group than in the control group. The most common morbidity related to tonsillectomy was postoperative throat pain (mean length 13 days, SD 4).

CONCLUSIONS

Adults with a history of documented recurrent episodes of streptococcal pharyngitis were less likely to have further streptococcal or other throat infections or days with throat pain if they had their tonsils removed.

TRIAL REGISTRATION

Clinical Trials NCT00136877.