Group Milleri Streptococci in paediatric infections

Streptococcus anginosus group infections in hospitalised children and young people

AIM

The Streptococcus anginosus group (SAG) comprises three bacterial species colonising the mouth and gastrointestinal and genitourinary tracts and capable of serious pyogenic infections. Although well-described in adults, studies in children are limited. Here, we characterise paediatric SAG infections from a single Australian centre.

METHODS

Hospitalised patients aged ≤18 years with positive SAG cultures from January 2009 to December 2019 were identified from Pathology Queensland's Gold Coast Laboratory database and their medical records were reviewed.

RESULTS

Two-hundred children (62% male), median age 12 years (interquartile range 6-16), with positive SAG cultures were identified. Overall, 90% received intravenous antibiotics, 89% underwent surgical drainage, 23% were readmitted and 15% required additional surgery. The most common sites were the abdomen (39%), soft tissues (36%) and head and neck regions (21%). Since 2011, Pathology Queensland reported SAG at the species level (n = 133). Of these, S. anginosus was the most prevalent (39%), then S. constellatus (34%) and S. intermedius (27%). Compared with the other two species, S. intermedius was most commonly associated with head and neck infections (relative risk (RR) = 2.2, 95% confidence interval (CI) 1.4-3.5), while S. constellatus (RR = 1.7, 95% CI 1.2-2.4) and S. anginosus (RR = 1.5, 95% CI 1.0-2.0) were each associated with a higher risk of intra-abdominal infection than S. intermedius. Since February 2015, the number of children admitted with SAG-associated intra-abdominal infection per 1000 hospitalisations increased by 29% annually compared with an annual decline of 8% in previous years.

CONCLUSIONS

SAG infections occur at various anatomical sites. Despite antibiotics and surgical management, almost one-quarter are re-hospitalised for further treatment.

COMPLICATED PNEUMONIA WITH EMPYEMA CAUSED BY STREPTOCOCCUS ANGINOSUS IN A CHILD

Objective:

To highlight the pathogenicity of Streptococcus anginosus, which is rare in pediatric patients, but can cause severe infections that are known to have a better outcome when treated early with interventional procedures and prolonged antibiotic therapy.

Case

description: The patient is a 6-year-old boy with global developmental delay, examined in the emergency room due to fever and respiratory distress. The physical examination and diagnostic workout revealed complicated pneumonia with empyema of the left hemithorax; he started antibiotic therapy and underwent thoracic drainage. Pleural fluid cultures grew Streptococcus anginosus. On day 11, the child had a clinical deterioration with recurrence of fever, hypoxia, and respiratory distress. At this point, considering the causative agent, he was submitted to video-assisted thoracoscopic decortication, with good progress thereafter.

Comments:

Streptococcus anginosus is a commensal bacterium of the human oral cavity capable of causing severe systemic infections. Although reports of complicated thoracic infections with this agent are rare in the pediatric population, they have been increasing in adults. Streptococcus anginosus has a high capacity to form abscess and empyema, requiring different therapeutic approaches when compared to complicated pneumonia caused by other agents.

Sites of infection associated with Streptococcus anginosus group among children

Streptococcus anginosus group (SAG) are parts of normal flora of the oral cavity and associated with abscess forming in various sites on the body. Although the clinical features of infections caused by each member of the SAG in adults has been reported, it has not well been known in children. The aim of this study was to clarify the site of infections associated with individual SAG species among children. Medical records from March 2010 to July 2016 were reviewed at Tokyo Metropolitan Children's Medical Center. Any SAG species (S. anginosus, S. constellatus, or S. intermedius) isolated from clinical samples and recorded in the microbiological database were included for analysis. Analysis of 52 infectious episodes found that S. anginosus was most frequently isolated from the genitourinary tract, and 73% of genitourinary tract infection was balanoposthitis. All genitourinary tract infections were associated with S. anginosus. These findings were different from those of a previous study of adults. Of all the patients, 45 patients (87%) had polymicrobial infections. More than 70% of patients infected by S. anginosus and S. constellatus were co-infected by obligate anaerobes, in comparison with only 21% of S. intermedius cases. Among the obligate anaerobes species, Bacteroides spp. was significantly accompanied with S. anginosus. Susceptibility to penicillin, ampicillin, cefotaxime, erythromycin, clindamycin, levofloxacin, and vancomycin was 100%, 100%, 100%, 77%, 89%, 97% and 100%, respectively. S. anginosus was often isolated from balanoposthitis among children.

Epidemiologic and Microbiologic Characteristics of Occult Bacteremia Among Febrile Children in Southern Israel, Before and After Initiation of the Routine Antipneumococcal Immunization (2005-2012)

BACKGROUND

Little is known about the incidence and dynamics of occult bacteremia (OB) among infants/young children following the introduction of pneumococcal conjugate vaccines (PCVs) into the national immunization program in Israel in 2009-2010. The aim of this study was to characterize the epidemiologic and microbiologic picture of OB among febrile infants/children aged 3-36 months in southern Israel, before and after PCVs introduction.

METHODS

Retrospective study enrolling all infants/young children attending the emergency room of a tertiary medical center in southern Israel with fever without source, discharged, and reported with a positive blood culture.

RESULTS

Of 453 true bacteremias, 89 (19.6%) were defined as OB. OB rate was 0.22%; a significant decrease was recorded in OB rates, with the highest rate during 2005 (0.34%) and the lowest during 2011 (0.15%). OB cases decreased in post-PCV (2010-2012) versus prevaccination period (2005-2009) from 66/22,256 cases (0.3%) to 23/13,213 cases (0.17%; p = 0.03). Most frequent single OB pathogens were Streptococcus pneumoniae, Streptococcus viridans spp., and Kingella kingae (39.3%, 10.1%, and 9.0%, respectively); Enterobacteriaceae spp. were isolated in 10 cases (11.2%). No changes were recorded in S. pneumoniae-OB cases; K. kingae-OB decreased significantly (p = 0.047). None of the S. pneumoniae serotypes isolated during 2011-2012 belonged to 13-valent PCV (PCV13). An increase in non PCV13 serotypes was recorded during 2011-2012 (3/3, 100% vs. 7/32, 21.9%, p = 0.01).

CONCLUSION

OB rates decreased significantly following the introduction of PCVs. S. pneumoniae was the most frequent isolated pathogen in OB, but in lower percentages compared with the medical literature. No PCV13 serotypes were detected as a cause of OB during 2011-2012.