Streptococcal pharyngitis

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Epidemiology and prevention of streptococcal
pharyngitis Prepared by Ghada Mohamed Ahmed
BedairGhada_epi_at_yahoo.comB.Sc, Nursing, Faculty
of Nursing, Alexandria University.Master degree
in Epidemiology, High Institute of Public Health,
Alexandria University, Egypt
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Introduction
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Definition

• - Pharyngitis refers to inflammation of the
  structures of the pharynx.
• - The tonsils are most often affected.
• - The term pharyngitis, tonsillitis,
  tonsillopharyngitis and pharyngotonsillitis are
  interchangeable and do not imply an
  etiology.

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Causes

• - Up to 85 are caused by viruses.
• - Pharyngitis caused by Streptococcus pyogenes is
  the most common bacterial pharyngitis diagnosed
  in developed countries.
• SStreptococcus pyogenes , Group A- Beta
  haemolytic streptococci (GAßHS) is a gram
  positive, catalase negative, facultative
  anaerobe, that occurs in pairs or chains in
  cultures.
• GAßHS divided into more than 130
  distinct M serotypes.

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• GAßHS represent one of the most
  impressive human pathogens, it cause a wide
  array of serious infections including
• Pharyngitis
• Respiratory infection
• Skin infection (impetigo, erysipelas)
• Endocarditis
• Meningitis
• Puerperal sepsis
• Arthritis
• Scarlet fever

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PPublic health importance

• It is a precursor of two serious non-suppurative
  sequlae
• acute rheumatic fever, and
• post streptococcal glomerulonephritis.

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• Risk factors
• All group A streptococcal diseases are most
  common in setting of poverty, overcrowding, and
  low socioeconomic status, where living
  conditions promote transmission of the
  organism.
• 2. Streptococcal pharyngitis most often occurs
  in the late winter and early spring.
• 3. It affects schoolage children, particularly
  those 5-11 years old, but children and adults of
  all ages can be infected with group A
  streptococci.

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of GAßHS Mode of transmission

• GAßHS spread when a person coughs or
  sneezes infected large droplets that come into
  contact with another persons mucous membrane.
  The highest risk of transmission occurs during
  the acute stage.

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Magnitude of the Problem

• GAßHS diseases are highly prevalent in some
  regions, but may be less in others, For
  example, RHD is very common in Sub-Saharan
  Africa and the Pacific, common in
  South-Central Asia and the Middle East/North
  Africa, but less common in many Asian
  countries and Latin America.
• From 1985 through 2002, the world Health
  Organization (WHO) estimated that over 600
  million cases of symptomatic GAS pharyngitis
  occur annually worldwide.

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• GAßHS pharyngitis in some developed countries
• Acute pharyngitis is one of the most common
  illnesses for which patients seek medical advice
  in the more developed countries. accounting for
  nearly over 7 million visits to pediatricians
  each year in the United States. In this country.
• Oliver (2000) in England reported that the
  prevalence of GAßHS was 20.
• In France, Chiadmi et al (2003) stated that the
  prevalence was 33.
• In Belgium, sore-throat is one of the most
  frequent causes of consultation seen by general
  practitioner, and GAS has been isolated in 20.3
  of cases.
• In Chile, a study done by Munoz et al
  (2003-2004), streptococcus sore-throats were
  detected in 37 of cases.

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GAßHS pharyngitis in some developing countries

• In low income countries, there are few
  prospective studies that provide data on group A
  streptococcal pharyngitis, its epidemiology and
  clinical presentation.

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• In India, it is estimated that approximately 7
  sore throat episodes occur per child per year,
  there are as many as 20-30 million cases of
  streptococcal pharyngitis may occur annually in
  that country in Asia.
• In Iran (2000) Jasir et al reported a
  prevalence of 30.
• Shrestha et al in Nepal (2001) reported
  prevalence 7.2.
• Dos Santos and Berezin in Brazil (2004) found the
  prevalence of GAßHS pharyngitis (24.4) .
• In Taiwan Lin et al (2003) reported s prevalence
  of 21.4
• A study done in 3 countries from September 2001
  to August 2003, Rio de Janeiro (Brazil), Cairo
  (Egypt), Zagreb (Croatia), the proportion of
  children with a positive GAßHS culture differed
  between countries 24.6 in Brazil, 42.0 in
  Croatia, and 27.7 in Egypt.

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Clinical Pictures
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Diagnosis of streptococcal pharyngitis
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Complications of GAßHS pharyngitis
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Prevention and control of GAßHS pharyngitis

• Primary prevention
• A) Reducing overall exposure to GAS.
• 1) Improving living standards.
• 2) Adequate nutrition.
• 3) Provision of easily accessible laboratory
  facilities for diagnosis of GAßHS.
• 4) Pasteurization of milk and exclude of
  infected people from handling food.
• 5) Health education to public and health workers
  about modes of transmission and the relationship
  of streptococcal sore throat to ARF/RHD.

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• B) Immunization
• Although there have been multiple attempts
  to produce a GAßHS vaccine for approximately a
  century, none of the candidate vaccines has
  proceeded beyond preliminary animal or human
  studies until recently.

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Secondary prevention

• A- Treatment of GAßHS pharyngitis
• The gold standard of therapy for GAßHS is
  penicillin.
• Treatment of GAßHS pharyngitis should,
• 1) Relieve the symptoms of the acute illness.
• 2) Eliminate transmissibility.
• 3) Prevent both suppurative and nonsupporative
  sequelae.

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• It has been very well demonstrated that a 10
  days course of an appropriate oral antibiotic
  (usually oral penicillin V) or a single dose of
  long-acting intramuscular penicillin (benzathine
  penicillin BPG) if administered within 9 days of
  the onset of symptoms of GAßHS pharyngitis, will
  prevent most cases of ARF.

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B) Primary prophylaxis of RF

• This refers to the prevention of ARF by timely
  and complete antibiotic treatment of
  symptomatic GAßHS pharyngitis.
• CSurgical approach to recurrent GAßHS
  pharyngitis
• More clearly defined indicators for surgical
  intervention include patients with peritonsillar
  abscess or severe obstructive symptoms.

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Tertiary prevention

• This refers to measures to reduce the severity
  or long-term impact of GAS diseases. In practice,
  it mainly refers to management of patients with
  RF/ RHD.

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AIM OF THE STUDY
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• General objective
• To study group A-ß haemolytic streptococci
  (GAßHS) among school children with
  Pharyngotonsillitis in Alexandria (Egypt).

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• Specific objectives
• 1- To estimate the prevalence of GAßHS
  infection among school children with
  pharyngotonsillitis .
• 2- To identify the predictive clinical findings
  of GAßHS pharyngitis.
• 3- To determine the seasonal variations of
  GAßHS pharyngitis.

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SUBJECTS AND METHODS
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• Study design
• Cross-sectional approach
• Study setting
• School health insurance clinics in six
  educational zones in Alexandria (Egypt).
• Target population
• School children aged 6-15 years old with
  pharyngotonsillitis in primary and preparatory
  education in Alexandria.

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• Sampling design
• Based on data from the Medical Affairs for
  School Children, the sample size was calculated
  by using epi-info program, on the assumption that
  the prevalence is 17 according to the last
  study by zaher et al, the calculated sample size
  at 95 confidence interval and at degree of
  precision of 3 was found to be 600
  students.

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• To fulfill this sample size multistage sample
  technique was used. One school health insurance
  clinic was randomly chosen from each educational
  zone. Then the total sample size was
  proportionally distributed on chosen health
  clinics.

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• Ethical considerations
• 1- Getting approvals from the Medical Affairs for
  School Children.
• 2- Informed consent was taken from enrolled child
  and parents or guardian accompanying the child to
  the clinic.

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• Study tools
• 1- A predesigned questionnaire interview with
  child and his/her parent, inquiring about
• Demographic characteristics( child name, age,
  sex,.......)
• Co-morbidity and past history of diseases for
  both child and his family.
• Clinical signs and symptoms predicting GAßHS
  pharyngitis which extracted from the literature.
• 2- Throat swab was taken from each child to be
  cultured on blood agar plate.

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• Inclusion criteria
• Sore- throat and/or difficult swallowing.
• Pharyngeal erythema, exudates.
• Or tonsilar enlargement, redness with or without
  exudates.
• Fever.
• Enlarged tender anterior cervical lymph nodes.
• Exclusion criteria
• Oral antibiotic use within 3 days or
  intramuscularly administered antibiotics within
  the 20 days prior to the clinic visit.
• History of previous RF or RHD, or presence of
  another illness requiring hospitalization.

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• Implementation phase
• Selection and examining of cases were done by
  clinic physician.
• Questionnaire interview, Throat swab sampling
  and cultures were made by the researcher.
• The cultures were made in Microbiology
  Department of High Institute of Public Health.

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• Transport samples to the laboratory
• The swabs were transported to the laboratory
  within 2 hrs. If there is delay in
  transportation to the laboratory , they were put
  in transport medium (stuarts media)
• Procedure of cultivation and identification
• Swabs were streaked onto crystal violet
  blood agar plate and incubated at 37C in
  5-10 CO2 atmosphere using candle jar.
• After overnight incubation, the plate were
  examined for bacterial growth, colonial
  morphology and haemolytic characteristics.

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• Colonies that appeared on blood agar plate
  as pinpoint, transparent, circular colonies
  surrounded by wide zone of ß haemolysis were
  suspected as GAßHS, and subcultured on another
  crystal violet blood agar plate and tested for
  their sensitivity to bacitracin discs
  (0.05units).

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Interpretation of results

• Beta haemolytic streptococci strains showing
  zone of inhibition around bacitracin disc ,
  were considered to be GAßHS.

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Data analysis and interpretations

• FFrequency distribution and chi-square test
  were calculated for each signs and symptoms.
  
• LLogistic regression analysis was used to
  model the probability of GAßHS pharyngitis
  occurrence.

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Results
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• Overall prevalence of GAßHS pharyngitis
  among primary and preparatory school children
  in Alexandria during 2005-2006.

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Prevalence of GAßHS pharyngitis cases
according to educational zones among primary
and preparatory school children in
Alexandria (Egypt) during 2005-2006.
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Prevalence of GA?HS pharyngitis cases
according to sex in Alexandria during
2005-2006
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PPrevalence of GAßHS pharyngitis cases
according to educational stage among primary
and preparatory school children in Alexandria
during 2005-2006.
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Prevalence of GAßHS pharyngitis cases
according to age group among primary and
preparatory school children in Alexandria
during 2005-2006.
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PPrevalence of GAßHS pharyngitis cases
according to Season among primary and
preparatory school children in Alexandria
during 2005-2006.
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Distribution of cases according to history
of family diseases among primary and
preparatory school children in Alexandria
during 2005-2006.
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Distribution of cases according to history of
recent contact with pharyngotonsillitis among
primary and preparatory school children in
Alexandria during 2005-2006.
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Distribution of cases according to number
of sore-throat attacks per year among primary
and preparatory school children in
Alexandria during 2005-2006.
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predictors for GAßHS pharyngitis among
primary and preparatory school children in
Alexandria during 2005-2006
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CONCLUSIONS
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CONCLUSIONS

• From the present study, it could be concluded
  that
• The prevalence of GAßHS infection among selected
  primary and preparatory school children suffering
  from pharyngotonsillitis in Alexandria during
  2005-2006 was 30.3.
• The peak prevalence of GAßHS pharyngitis
  occurred in spring and winter.
• Cases who reported family history of rheumatic
  disease had the highest percent of positive
  culture of GAßHS pharyngitis (37.2).
• Cases who reported a history of recent
  contact with pharyngotonsillitis had a higher
  prevalence of GAßHS pharyngitis (58.8), compared
  to cases without such history, the prevalence of
  GAßHS among whom was 41.2.
• The predictors which were found to be highly
  associated with GAßHS pharyngitis were recent
  contact with a pharyngotonsillitis case, tender
  cervical lymph nodes, enlarged cervical lymph
  nodes, enlarged tonsils, joint/limb pain, and
  vomiting.

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• RECOMMENDATIONS

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RECOMMENDATIONS

• To encourage national authorities to include this
  disease and its complications in their public
  health priorities.
• To develop an educational materials and training
  programs for health care providers and laboratory
  personnel which include standard guidelines
  addressing recognition of GAßHS pharyngitis,
  clinical diagnosis, case management, and
  prevention of group A streptococcal sequelae.

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• 3- To Upgrade the skills of school health
  physicians and To train them on early detection
  of GAßHS pharyngitis cases depending on the
  predicting signs and symptoms.
• 4- To carry out Further research to continually
  re-evaluate continually the clinical signs and
  symptoms associated with GAßHS pharyngitis in
  light of epidemiologic and demographic
  characteristics of such infection in our
  community to reach an accurate clinical
  diagnosis.

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Thank you