Insensitivity of rapid antigen detection methods and single blood agar plate culture for diagnosing streptococcal pharyngitis.

OBJECTIVE--To compare the sensitivity of five group A streptococcal antigen detection systems and single blood agar plate culture with a two-plate culture method for diagnosis of streptococcal pharyngitis. DESIGN--Two simultaneous throat swabs were obtained from consecutive patients with suspected streptococcal pharyngitis. One swab was tested for streptococcal antigen by physicians' office nurses and the other was cultured on both aerobic blood agar and anaerobic trimethoprim-sulfamethoxazole blood agar plates. SETTING--Community office practice and community hospital laboratory. PARTICIPANTS--Consecutive outpatients seen by one of four pediatricians or a family practice physician. MAIN OUTCOME MEASURES--Results of rapid streptococcal antigen tests were compared with culture results either on a single aerobic blood agar plate or on the two-plate culture method. RESULTS--On throat swabs from 755 consecutive outpatients, the two-plate culture method detected 261 cases (defined as 100%) of group A streptococcal pharyngitis. The anaerobic trimethoprim-sulfamethoxazole plate alone, read at 1 and 2 days, detected 245 cases (94%). The blood agar plate used alone detected 189 cases (72%) at 2 days and 151 cases (58%) at 1 day. Antigen detection test results were positive for 106 throat specimens (41%), with individual kit sensitivity ranging from 31% to 50% compared with the two-plate culture method. Antigen detection test sensitivity decreased with decreasing colony counts. Antigen kit false-positivity rates varied from 0 to 28%. CONCLUSIONS--We conclude that the single blood agar plate culture and the antigen detection tests are insensitive, possibly leading the physician toward undertreatment and risking immunologic, local, or distant sequelae. The two-plate culture method should be the standard of practice to rule out streptococcal pharyngitis.     

I. Clinical evaluation

A study was undertaken to evaluate the therapy of streptococcal pharyngitis. The compliance of 118 patients with beta-hemolytic streptococcal pharyngitis to follow-up was 72%. Of 74 patients checked by means of urine tests 66 took their oral medication. No differences were detected in the clinical and bacteriological results (>98% streptococcal eradication) after the 7th or 10th day of therapy after taking either cephalexin or penicillin.

It was concluded that: (a) for effective surveillance and follow-up special attention should be given to the uncooperative segment of the patient population; (b) a seven-day course of penicillin may be satisfactory in the eradication of BHS from the throat; and (c) cephalexin appears to be an effective alternative to penicillin for the treatment of streptococcal pharyngitis.

     

Streptococcal pharyngitis--rapid diagnosis by Gram stain.

Group A beta-haemolytic streptococci were isolated from 51 (9.8%) of 519 patients with pharyngitis. Throat culture results showed the mean sensitivity, specificity and predictive value of a positive Gram-stained smear of pharyngeal secretions as 70%, 89% and 69%. The data suggest that Gram staining of a smear directly from the swab is as accurate as and more speedy than a culture from the pharyngeal secretion for diagnosis of streptococcal pharyngitis.     

Streptococcal pharyngitis. Placebo-controlled double-blind evaluation of clinical response to penicillin therapy

Forty-four children with a clinical diagnosis of streptococcal pharyngitis had throat cultures performed at the initial evaluation and were assigned by randomization to receive either oral penicillin or a placebo for 72 hours. The treating physician, who remained blind to the treatment regimen, recorded the child's temperature and assessed the presence and severity of other signs and symptoms initially and at 24, 48, and 72 hours. The throat culture was positive for group A beta-hemolytic streptococci in 26 (59%) of the initial study group, and most of these children developed a fourfold or greater titer rise in antistreptococcal antibodies in their serum, confirming the diagnosis of streptococcal pharyngitis. Statistically significant clinical improvement was observed in the group of 11 children who were later shown to have been taking penicillin compared with the group of 15 who had taken the placebo. Significant differences in the presence and degree of fever and severity of symptoms persisted in the placebo-treated group for 48 hours. We conclude that early penicillin treatment of children with streptococcal pharyngitis significantly alters the acute clinical course of the disease.     

Treatment of sore throat in light of the Cochrane verdict: is the jury still out?

There are few good-quality studies of the effectiveness of antibiotic treatment of proven group A streptococcal (GAS) pharyngitis in children; available data suggest that antibiotics may reduce symptom duration. While there is limited justification for antibiotic treatment of GAS pharyngitis to prevent acute rheumatic fever in non-Indigenous Australians, there is no justification for routine antibiotic treatment of all patients with sore throat. Two strategies are open to clinicians: not to treat GAS pharyngitis with antibiotics, in which case no investigations should be done; or to treat cases of sore throat with clinical features that suggest GAS, in which case diagnosis should be confirmed with a throat swab, and penicillin started while awaiting the result. Penicillin should be discontinued if the swab is negative, or continued for 10 days if it is positive for GAS. Surveillance of GAS infections and acute rheumatic fever is needed in Australia, as are further studies of effectiveness (including cost-effectiveness) of antibiotic treatment of proven GAS pharyngitis.     

Acute rheumatic fever in Wisconsin

Medical records of patients discharged from Children's Hospital of Wisconsin from January 1980 to May 1988 who fulfilled the revised Jones criteria for acute rheumatic fever were reviewed. A total of 13 patients were hospitalized with a first attack of acute rheumatic fever during this period. Migratory polyarthritis was present in 92% of the patients and carditis in 62%. Mitral regurgitation was present in all cases of carditis. Only six patients (46%) had a history of a preceding streptococcal infection, half of whom were treated with antibiotics. While there is no evidence to support a new outbreak of acute rheumatic fever in Wisconsin, our data demonstrate that the disease is still prevalent within the eastern region of the state. Patients with Group A streptococcal pharyngitis must be identified and treated to prevent this disease from increasing in incidence.     

Scarlet fever can mimic toxic shock syndrome

We describe a patient who presented with a widespread erythematous rash, diarrhoea, confusion, pre-renal uraemia and hyponatraemia. The diagnosis of staphylococcal toxic shock syndrome seemed likely as she was menstruating and there was no evidence of pharyngitis. A rising ASO titre confirmed a streptococcal aetiology and thus 'toxic' scarlet fever. Toxic shock syndrome and toxic scarlet fever are compared.     

Treatment of streptococcal pharyngitis revisited

Penicillin has remained the drug of choice for treatment of patients with streptococcal pharyngitis for the past four decades. From the early 1950s into the 1970s, a single injection of intramuscular penicillin G benzathine, alone or in combination with penicillin G procaine, was the preferred treatment. Because this regimen consistently produced the highest cure rate and because compliance was assured, it evolved as the gold standard with which other treatment regimens were compared. In the late 1960s and the 1970s, studies showed that in private practice settings with counseling as to the need to take oral penicillin for a full ten days to prevent rheumatic fever, good compliance with results equal to intramuscular penicillin G benzathine could be achieved. By the early 1980s, oral treatment was preferred by most primary physicians in the United States. Oral penicillin V in a dosage of 250 mg, twice daily for ten days, affords optimal treatment for children. In areas where rheumatic fever is still prevalent, particularly in poor and crowded inner-city populations where medical care is episodic, follow-up may be lacking, and compliance in taking oral penicillin cannot be relied on, treatment with intramuscular penicillin G benzathine remains preferred. Studies now confirm that early treatment of streptococcal pharyngitis can reduce the duration of symptoms to less than 24 hours in most cases, decrease the incidence of suppurative complications, limit spread of the disease in the family and community, and permit earlier return of the child to school. Recently developed tests that permit rapid, laboratory-confirmed diagnosis of streptococcal pharyngitis directly on the throat swab at the initial clinic visit may soon guide early treatment with these inherent benefits.     

Molecular Epidemiological Analysis of Group A Streptococci Isolated from Children in Chaoyang District of Beijing, 2011: emm Types, Virulence Factor Genes and Erythromycin Resistant Genes

Group A streptococcus(GAS)causes a wide range of diseases in the human population.GAS diseases are more common in children than in adults,with clinical manifestations ranging from pharyngitis and impetigo to invasive infections and post streptococcal sequelae,such as acute rheumatic fever and acute post-streptococcal glomerulonephritis[1].GAS harbors a host of virulence factors that contribute to its complex pathogenicity and differences in the disease severity and frequency.M protein,one of the major virulence factors,is encoded by the emm gene induces a type of specific host immune response and confers antiphagocytic properties.Sequence analysis of the emm gene has become an important     

Streptococcal pharyngitis and acute rheumatic fever in Rhode Island

A comprehensive survey of physicians, laboratories, and hospital records in Rhode Island showed that more than 157,000 throat cultures for a population of 930,000 people were done in 1980. Eighty-seven percent of primary care physicians prescribed antibiotic therapy before culture results were known, and almost 40% continued antibiotic therapy for ten days regardless of culture results. The throat culture positivity rate for beta-hemolytic Streptococcus was 17% statewide in 1980. Only three definite and seven possible cases of acute rheumatic fever were identified by hospital chart reviews and a physician survey covering the five years 1976 through 1980. Current throat culture practices probably have little influence on treatment of streptococcal pharyngitis and control of rheumatic fever in the state.     

The accuracy of experienced physicians' probability estimates for patients with sore throats. Implications for decision making

Ten physicians recorded their treatment decisions and estimated probabilities of streptococcal infection for patients with sore throats. Of 308 throat cultures, 15 (4.9%) were positive for group A streptococci. The physicians overestimated the probability of a positive culture for 81% of their patients and their estimates and treatment decisions were strongly associated. Of 104 patients treated before culture results were available, only eight had positive cultures. Probability overestimation may have been due to neglect of the low culture-positive rate, assignment of undue importance to weakly predictive or highly intercorrelated clinical features, and a value-induced bias, occurring when features important for treatment are erroneously linked to the likelihood of disease. Cognitive limitations in information processing may limit the effectiveness of pharyngitis management protocols that require subjective estimates of disease probability.     

The comparative cost-effectiveness of statistical decision rules and experienced physicians in pharyngitis management

We examined whether probability-based decisions for streptococcal pharyngitis, using probabilities derived from predictive models along with Tompkins' decision rules, could be more cost-effective than the actual decisions of ten physicians. We retrospectively calculated the probability of a positive throat culture ("disease") for each of 310 patients using four different models based on discriminant analysis (1), a branching algorithm (2), and logistic regression (3 and 4). "Projected decisions" were based on these probabilities and Tompkins' rules. We calculated direct medical and indirect costs per correct action taken (diseased patient-treated or nondiseased patient-not-treated). Two models' projected decisions were more cost-effective than the physicians'. Model 1 primarily would have reduced treatment costs (leaving no diseased patient untreated); model 4 primarily would have reduced throat culture costs (with 15% projected undertreatment). While using statistical decision rules may be cost-effective in this setting, their adoption should be consistent with physician and patient priorities.     

人体成分与RFS低阳性评分慢性咽炎的相关性

目的 观察人体成分与反流体征指数评分(RFS)量表低阳性评分慢性咽炎的相关性。方法 选取2020年7月至2021年9月期间成都大学附属医院收治临床诊断为慢性咽炎,且RFS评分为8～10分的患者250例为病例组,以同期健康体检人群为对照组。比较两组研究对象的一般资料、人体成分等相关指标,采用多因素logistic回归分析法分析各危险因素对RFS低阳性慢性咽炎的影响。结果 两组研究对象性别、年龄、吸烟史和饮酒史等比较,差异无统计学意义(P>0.05)。病例组焦虑和失眠症的比例分别为15.6%和19.2%,对照组分别为6.8%和8.8%,病例组高于对照组,差异有统计学意义(P＜0.05)。病例组体脂肪量、体脂百分比以及内脏脂肪均高于健康对照组,差异有统计学意义(P＜0.05)。多因素logistic回归分析显示内脏脂肪量是RFS低阳性慢性咽炎的独立危险因素(OR=1.095;95% CI:1.019~1.179;P=0.014)。结论 人体成分中内脏脂肪是RFS低阳性评分慢性咽炎的危险因素。     

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.     

复方余甘子含片对人体口咽部菌群调节作用的初步研究

目的通过观察复方余甘子含片对人体口咽部菌群的调节作用,初步探讨其防治慢性咽炎的作用机理。方法选择健康人群及慢性咽炎人群含服复方余甘子含片,观察含片前后口咽部菌群的变化情况;同时进行含片对口咽部常见致病菌及优势菌甲型链球菌的体外抑菌实验。结果复方余甘子含片在体外对金黄色葡萄球菌、乙型溶血性链球菌、肺炎链球菌有一定的抑制作用,但对优势菌甲型链球菌无抑制作用;对慢性咽炎人群有促进优势菌甲型链球菌生长的作用。结论复方余甘子含片通过对口咽部优势菌甲型链球菌的生长促进,恢复局部菌群平衡,从而对慢性咽炎有一定的防治作用。     

呼吸道粘膜固有微生物种群与咽炎发病的关系

目的 探讨呼吸道粘膜微生物种群丰度和密度的变化与咽炎的病理学关系。方法 对急性咽炎和慢性咽炎病人及正常人群咽后壁微生物种群进行定位、定性、定量分析。结果 正常人咽粘膜菌群为4－5个菌属,6－9个菌种,以α－溶血性链球菌群、奈瑟菌属、棒状杆菌属、葡萄球菌属、厌氧链球菌群和梭状杆菌属为主,分别占可培养微生物的40％－60％、20％－30％、5％－10％、4％－8％和0％－40％。急性咽炎病原菌检出率流感嗜血杆菌占65％。结论 外籍菌与原籍菌的演替和消长与急性咽炎的发生、发展有着直接关系;固有微生物群落急性感染的微群落构象与慢性感染有显著差别。群落内部紊乱是慢性炎症的特征性指标。     

误诊为咽炎的亚急性甲状腺炎28例分析

目的：探讨导致亚急性甲状腺炎误诊为咽炎的主要原因。方法回顾性分析2010年12月～2013年6月昆明医科大第一附属医院28例亚急性甲状腺炎误诊为咽炎患者的临床资料,研究并总结导致亚急性甲状腺炎误诊为咽炎的主要原因。结果发生亚急性甲状腺炎误诊为咽炎的患者大多为青年或（和）中年妇女,发生误诊的女性数量约是男性数量的8倍。亚急性甲状腺炎的特点主要是咽喉疼痛,另外,还合并一侧或双侧甲状腺肿大,出现TSA下降,T 3及T 4升高。结论亚急性甲状腺炎的临床症状不明显、发病隐匿,由于耳鼻喉科医生检查不仔细,对该病缺乏认识,常导致亚急性甲状腺炎被误诊为咽炎。     

Managing sore throat: a literature review. I. Making the diagnosis.

OBJECTIVE: To assess the justification for the routine use of investigations in the diagnosis of bacterial causes of sore throat. DATA SOURCES: The literature from 1945 to 1990 was systematically screened to identify studies that addressed diagnosis of bacterial infection and the efficacy of antibiotics in sore throat, using the key-words "pharyngitis" and "tonsillitis". RESULTS: Difficulties were identified with clinical methods and investigations that identify streptococcal infections. The practice of throat-swab culture--the "gold standard"--appears to have developed as a strategy to protect patients from acute rheumatic fever. However, this method may be limited in its usefulness for protection against acute rheumatic fever because: (i) in many cases in which the streptococcus is isolated from symptomatic patients there is no serological evidence of infection; (ii) there are very high asymptomatic carrier rates of the streptococcus; (iii) even after adequate treatment with penicillin there are high bacteriological failure rates; and (iv) those organisms that can be isolated from the mucosal surface are a poor representation of organisms lying deep in the tissues. Evaluation of other diagnostic techniques such as Gram's stain and rapid antigen testing, as well as decision analysis, has also been hampered by the difficulties encountered with use of this inadequate gold standard. CONCLUSION: There is little indication from the literature that any routine system of identifying bacterial causes of sore throat is helpful to the clinician.     

Can group A beta haemolytic streptococcal sore throats be identified clinically?

OBJECTIVE: To differentiate the clinical manifestations of a Group A beta haemolytic streptococcal throat infection from viral and other bacterial infections. SETTING: Outpatients' department, Lady Ridgeway Hospital, Colombo. PATIENTS AND METHODS: Children aged 3 to 12 years attending with a sore throat. Throat swabs were taken and relevant details were obtained using a questionnaire. They were examined for significant cervical lymphadenopathy and tonsillar exudate. RESULTS: Group A beta haemolytic streptococci were isolated from 61 (44.5%) throat swabs. Clinical differentiation of Group A beta haemolytic streptococcal sore throats was not possible as none of the symptoms or signs were significantly associated with the presence of this organism. CONCLUSIONS: Group A beta haemolytic streptococcal sore throats cannot be identified clinically, so that throat swabs for culture are necessary in children with sore throat. In the absence of this facility, it is reasonable to treat sore throats in children as for beta haemolytic streptococci.     

Poststreptococcal reactive arthritis

Acute rheumatic fever is a delayed inflammatory disease that follows streptococcal infection of the throat. Poststreptococcal reactive arthritis is a sterile arthritis associated with antecedent streptococcal infection in patients not fulfilling the Jones criteria for acute rheumatic fever. Poststreptococcal reactive arthritis has been reported to have lower-extremity predominance and, therefore, should be included in the differential diagnosis of patients with lower-extremity arthritis. A review of the literature, distinguishing poststreptococcal reactive arthritis from acute rheumatic fever, and treatment options are discussed here. A case report is also presented.