Published 31 December 2008, doi:10.1136/bmj.a2964
Cite this as: BMJ 2008;337:a2964

Practice

Lesson of the Week

Outbreak of Streptococcus pneumoniae serotype 1 pneumonia in a United Kingdom school

¹ Paediatric Respiratory Unit, Freeman Hospital, Newcastle upon Tyne NE7 7DN, ² Health Protection Agency North East, Northern Office, Citygate, Newcastle upon Tyne NE1 4WH, ³ Health Protection Agency, Centre for Infections, London NW9 5EQ, ⁴ Microbiology Laboratory Service, Northumbria Healthcare NHS Foundation Trust, North Tyneside General Hospital, North Shields NE29 8NH

Healthcare workers and teachers should report suspected outbreaks of serotype 1 pneumococcal disease early, and childhood immunisation should be considered

Pneumococcal pneumonia is not generally regarded as contagious.¹ Although epidemics of pneumococcal disease have been reported (in sub-Saharan Africa^{2 3} and Canada⁴), outbreaks of pneumococcal infection are uncommon and are generally restricted to high risk individuals such as alcoholics,⁵ residents in shelters for the homeless,⁶ and people living in close groups⁷ including military camps,⁸ prisons,⁹ day care centres,¹⁰ and nursing homes.¹¹ Recent reports have indicated that serotype 1 pneumococcus is largely responsible for the exponential increase in the incidence of empyema and complicated pneumonia seen in children in several countries over the past decade.^{12 13 14} There is also evidence of outbreaks of other forms of invasive serotype 1 disease in many countries.^{2 15 16} In contrast to most other invasive serotypes, carriage of serotype 1 is rarely detected in the nasopharynx of either adults or children, suggesting short duration of carriage or high virulence.^{17 18}

There have been no reports of outbreaks of pneumococcal pneumonia among UK children, but they have been reported in other countries.^{7 19} We describe an outbreak of serotype 1 pneumococcal pneumonia among young children in a school in northeast England.

Case reports

Clinical summary
Three cases of pneumococcal pneumonia in young children were initially reported in a primary school in North Tyneside. The dates of onset of illness were between 10 and 13 October 2006, and all three children, aged 4-5 years, attended the same reception class at the school and all were admitted to hospital with radiologically confirmed lobar pneumonia. The course of the disease was uncomplicated in two children, whose blood cultures were negative for Streptococcus pneumoniae. The third child had a positive blood culture and developed thoracic empyema (despite appropriate antibiotic treatment) requiring surgical drainage and mini-thoracotomy.

Public health action
After the notification of these three linked cases, public health action was taken to prevent further transmission of infection. The outbreak control team sought specialist advice from the Health Protection Agency Centre for Infections and arranged for all classroom contacts (64 pupils and staff) and household contacts (13) to receive rifampicin chemoprophylaxis. The uptake rate for classroom contacts was 97% (62/64) and for household contacts was 100%.

Further developments
Two further children from the school then presented on 15 and 20 November 2006, with clinical and radiological features of lobar pneumonia. Neither required inpatient hospital treatment, and both had received rifampicin chemoprophylaxis in response to the first cluster of cases.

Serotype 1 pneumococcus was detected in all five cases with a serotype-specific antigen detection assay from urine, but only one of the cases was positive for S pneumonia on blood culture. The serotype-specific assay, performed at the Health Protection Agency Centre for Infections, can detect 13 of the most common serotypes (1, 3, 4, 5, 6A, 6B, 7F/A, 8, 9V, 14, 18, 19A, 19F, and 23F)^{20 21} and was developed from an enzyme linked immunosorbent assay (ELISA).²² A pleural fluid sample from the child with a positive blood culture was also positive for serotype 1 using the serotype-specific assay. This assay has been validated but is not yet commercially available.²¹

The five urine samples were also positive on testing with the commercially available Binax NOW S pneumoniae antigen testing kit, which is reported to have 94% specificity and 86% sensitivity compared with blood culture results.²³ The two hospitalised children with negative blood culture results for S pneumoniae were also tested for respiratory viruses and mycoplasma, with negative results.

As there was evidence of ongoing transmission, the five infected children and their classroom and household contacts were offered the 23-valent pneumococcal polysaccharide vaccination (Pneumovax II), which includes serotype 1 antigen, and 77/83 (93%) received it. (None of the children had previously received the 7-valent pneumococcal conjugate vaccine.) Throat swabs were also obtained from the cases and contacts to test for carriage of the outbreak strain. Of the 81 people who provided swabs, one had evidence of carriage of S pneumoniae serotype 1 and was treated with azithromycin (12 mg/kg/day, once daily for five days) to eliminate it. No new cases of pneumococcal disease were reported after these further interventions.

Discussion

The incidence of complications associated with pneumococcal pneumonia, including necrotising pneumonia, parapneumonic effusion, thoracic empyema, and lung abscess has increased dramatically in UK children over the past decade.^{12 13 14} The reasons for this are still largely unknown, but it is at least partially related to the emergence of S pneumoniae serotype 1 as the dominant serotype. Whether this is due to changes in the host, organisms, or environment or as part of a naturally occurring cycle of dominant serotypes has yet to be determined.^{15 24}

In September 2006 the 7-valent pneumococcal conjugate vaccine was introduced for routine vaccination of UK children, but the cohort of children in this outbreak had not received it at the time of the outbreak. The vaccine contains antigen for serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F (which account for 70-80% of invasive isolates from European children), but it does not include antigen for serotype 1. After the vaccine’s introduction into the US vaccination programme in 2000, the incidence of pneumococcal parapneumonic empyema has continued to increase in US children, because of a non-significant increase in serotype 1 disease and the emergence of disease related to other serotypes not covered by the vaccine.²⁵ Enhanced pneumococcal surveillance has been in place in England and Wales for several years now in order to monitor changes in serotype prevalence after the introduction of the pneumococcal conjugate vaccine. Paediatric vaccination with a conjugate vaccine containing serotype1 antigen is not available in the UK, but such vaccines are at an advanced stage of development. It may become necessary to introduce such vaccines to prevent serotype 1 pneumococcal disease.

Antibiotic prophylaxis is not normally recommended for close family contacts of index cases of pneumococcal pneumonia. At the time of outbreak, there were no national guidelines available for the public health management of outbreaks of pneumococcal pneumonia. However, the Health Protection Agency’s Vaccine Programme Board has convened an expert group to develop evidence based guidelines.

When further cases were found in this North Tyneside outbreak, throat swabs were obtained to identify carriage of serotype 1 pneumococcus. Ideally, nasopharyngeal swabs should have been done, but this is an unpleasant procedure for children, and throat swabs were taken instead. This may have reduced the carriage detection rate. The one person who was found to be carrying serotype 1 pneumococcus was treated with azithromycin, which is effective in reducing nasopharyngeal carriage of pneumococci and was used to halt an outbreak of pneumococcal pneumonia in US marines.⁸

This report highlights the importance of early detection and notification of suspected outbreaks of pneumococcal disease to enable the early implementation of control measures. Healthcare workers and other professionals such as teachers have a vital role in reporting suspected outbreaks to public health professionals. The investigation of this outbreak was facilitated by the use of a non-invasive, multiplex, serotype-specific antigen detection assay, which identified the same serotype in all cases. The use of such tests should be considered as a diagnostic option, especially when blood samples are negative on culture testing.

This outbreak of serotype 1 pneumococcal pneumonia in children may support the need for immunisation against serotype 1 disease. Introduction of a vaccine that includes serotype 1 antigen should be considered if there is evidence that serotype 1 disease is an increasing public health problem.

Cite this as: BMJ 2008;337:a2964

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We thank Dr Michael Vincent, Northumbria Healthcare NHS Foundation Trust; Dr Mike McKean and Dr Chris O’Brien, Paediatric Respiratory Unit, Newcastle Teaching Hospitals.

Contributors: F-MK was chair of the outbreak control team that managed this outbreak and is guarantor for this article. DAS clinically managed one of the cases. F-MK and DAS had the idea for the article, AG performed the literature search and prepared the first draft of the article. The other authors contributed to the literature search and commented on the initial drafts of the manuscript.

Competing interests: RCG has been reimbursed by manufacturers of pneumococcal vaccines Wyeth and GSK (GlaxoSmithKline) for attending conferences, and his laboratory has received research funding from Wyeth. CLS has been funded by Wyeth for attending international conferences. MS has received funding from vaccine manufacturers to attend conferences and meetings. DAS has received research funding from Wyeth and funds for attending advisory boards and speaking from Wyeth and GSK. ELS has participated in a research project funded by Wyeth.

Ethical approval: Not required.

Patient consent obtained.

Provenance and peer review: Not commissioned; externally peer reviewed.

References

1. Musher DM. How contagious are common respiratory tract infections? N Engl J Med 2003;348:1256-66.[Free Full Text]
2. Leimkugel J, Adams Forgor A, Gagneux S, Pfluger V, Flierl C, Awine E, et al. An outbreak of serotype 1 Streptococcus pneumoniae meningitis in northern Ghana with features that are characteristic of Neisseria meningitidis meningitis epidemics. J Infect Dis 2005;192:192-9.[CrossRef][Web of Science][Medline]
3. Yaro S, Lourd M, Traoré Y, Njanpop-Lafourcade BM, Sawadogo A, Sangare L, et al. Epidemiological and molecular characteristics of a highly lethal pneumococcal meningitis epidemic in Burkina Faso. Clin Infect Dis 2006;43:693-700.[CrossRef][Web of Science][Medline]
4. Proulx JF, Dery S, Jette LP, Ismael J, Libman M, De Wals P. Pneumonia epidemic caused by a virulent strain of Streptococcus pneumoniae serotype 1 in Nunavik, Quebec. Can Commun Dis Rep 2002;28:129-31.[Medline]
5. Gratten M, Morey F, Dixon J, Manning K, Torzillo P, Matters R, et al. An outbreak of serotype 1 Streptococcus pneumoniae infection in central Australia. Med J Aust 1993;158:340-2.[Web of Science][Medline]
6. Mercat A, Nguyen J, Dautzenberg B. An outbreak of pneumococcal pneumonia in two men’s shelters. Chest 1991;99:147-51.[CrossRef][Web of Science][Medline]
7. Dagan R, Gradstein S, Belmaker I, Porat N, Siton Y, Weber G, et al. An outbreak of Streptococcus pneumoniae serotype 1 in a closed community in southern Israel. Clin Infect Dis 2000;30:319-21.[CrossRef][Web of Science][Medline]
8. Crum NF, Wallace MR, Lamb CR, Conlin AM, Amundson DE, Olson PE, et al. Halting a pneumococcal pneumonia outbreak among United States marine corps trainees. Am J Prev Med 2003;25:107-11.[Web of Science][Medline]
9. Hoge CW, Reichler MR, Dominguez EA, Bremer JC, Mastro TD, Hendricks KA, et al. An epidemic of pneumococcal disease in an overcrowded, inadequately ventilated jail. N Engl J Med 1994;331(10):643-8.[Abstract/Free Full Text]
10. Rauch AM, O’Ryan M, Van R, Pickering LK. Invasive disease due to multiply resistant Streptococcus pneumoniae in a Houston, Tex, day-care center. Am J Dis Child 1990;144:923-7.[Abstract/Free Full Text]
11. Nuorti JP, Butler JC, Crutcher JM, Guevara R, Welch D, Holder P, et al. An outbreak of multidrug-resistant pneumococcal pneumonia and bacteremia among unvaccinated nursing home residents. N Engl J Med 1998;338:1861-8.[Abstract/Free Full Text]
12. Eltringham G, Kearns A, Freeman R, Clark J, Spencer D, Eastham K, et al. Culture-negative childhood empyema is usually due to penicillin-sensitive Streptococcus pneumoniae capsular serotype 1. J Clin Microbiol 2003;41:521-2.[Free Full Text]
13. Tan TQ, Mason EO Jr, Wald ER, Barson WJ, Schutze GE, Bradley JS, et al. Clinical characteristics of children with complicated pneumonia caused by Streptococcus pneumoniae. Pediatrics 2002;110(1 Pt 1):1-6.[Abstract/Free Full Text]
14. Byington CL, Spencer LY, Johnson TA, Pavia AT, Allen D, Mason EO, et al. An epidemiological investigation of a sustained high rate of pediatric parapneumonic empyema: risk factors and microbiological associations. Clin Infect Dis 2002;34:434-40.[CrossRef][Web of Science][Medline]
15. Parent du Chatelet I, Traore Y, Gessner BD, Antignac A, Naccro B, Njanpop-Lafourcade BM, et al. Bacterial meningitis in Burkina Faso: surveillance using field-based polymerase chain reaction testing. Clin Infect Dis 2005;40:17-25.[CrossRef][Web of Science][Medline]
16. Hausdorff WP. The roles of pneumococcal serotypes 1 and 5 in paediatric invasive disease. Vaccine 2007;25:2406-12.[CrossRef][Web of Science][Medline]
17. Brueggemann AB, Spratt BG. Geographic distribution and clonal diversity of Streptococcus pneumoniae serotype 1 isolates. J Clin Microbiol 2003;41:4966-70.[Abstract/Free Full Text]
18. Hussain M, Melegaro A, Pebody RG, George R, Edmunds WJ, Talukdar R, et al. A longitudinal household study of Streptococcus pneumoniae nasopharyngeal carriage in a UK setting. Epidemiol Infect 2005;133:891-8.[CrossRef][Medline]
19. Cashman P, Massey P, Durrheim D, Islam F, Merritt T, Eastwood K. Pneumonia cluster in a boarding school—implications for influenza control. Commun Dis Intell 2007;31:296-8.[Medline]
20. Sheppard CL, Brown K, Harrison TG, Jones TR, Borrow R, George RC. A multiplex immunoassay for serotype-specific pneumococcal antigen detection directly from clinical specimens [abstract]. 5th International Symposium on Pneumococci and Pneumococcal diseases, 2006
21. Sheppard CL. the detection and characterisation of pneumococci in culture negative infections [PhD thesis]. London: St Mary’s College, 2006.
22. Leeming JP, Cartwright K, Morris R, Martin SA, Smith MD. Diagnosis of invasive pneumococcal infection by serotype-specific urinary antigen detection. J Clin Microbiol 2005;43:4972-6.[Abstract/Free Full Text]
23. NOW Streptococcus pneumoniae test. Scarborough ME, USA: Binax. www.binax.com/uploads/in710000_s_pneumo_pi_rev_4_6_6_07_001.pdf
24. Ramphul N, Eastham KM, Freeman R, Eltringham G, Kearns AM, Leeming JP, et al. Cavitatory lung disease complicating empyema in children. Pediatr Pulmonol 2006;41(8):750-3.[CrossRef][Web of Science][Medline]
25. Byington CL, Korgenski K, Daly J, Ampofo K, Pavia A, Mason EO. Impact of the pneumococcal conjugate vaccine on pneumococcal parapneumonic empyema. Pediatr Infect Dis J 2006;25(3):250-4.[CrossRef][Web of Science][Medline]

(Accepted 29 November 2008)

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