Oropharyngeal carriage and lower airway colonisation/infection in 45 tracheotomised children

Abstract

Background: A study was undertaken to determine the oropharyngeal carrier state of potentially pathogenic microorganisms (PPM) and the magnitude of colonisation and infection rates of the lower airways with these PPM in children requiring long term ventilation first transtracheally and afterwards via a tracheotomy. Methods: A 5 year, prospective, observational cohort study was undertaken in 45 children (33 boys) of median age 6.4 months (range 0-180) over a 5 year period at the Royal Liverpool Children's NHS Trust of Alder Hey, a university affiliated tertiary referral centre. The children were first admitted to the 20-bed paediatric intensive care unit (PICU) and, following placement of a tracheotomy, they were transferred to a four bedded respiratory ward. The two main indications were neurological disorders and airway obstruction. All children were ventilated transtracheally for a median period of 12 days (range 0-103) and, after placement of the tracheotomy, for a similar period of 12 days (range 1-281). Surveillance cultures of the oropharynx were taken on admission to the PICU and on the day of placement of the tracheotomy. Throat swabs were taken twice weekly during ventilation, both transtracheal and via the tracheotomy. Tracheal aspirates were taken once weekly and when clinically indicated (in cases where the lower airway secretions were turbid). Results: Twenty five patients (55%) had abnormal flora, mainly aerobic Gram negative bacilli (AGNB), particularly Pseudomonas aeruginosa, while the community PPM Staphylococcus aureus was present in the oropharynx of 37% (17/45) of the study population. The lower airways were sterile in six children; the other 39 patients (87%) had a total of 82 episodes of colonisation. "Community" PPM significantly increased once the patients received a tracheotomy, independent of the number of patients enrolled, episodes of colonisation/infection, and the number of colonised/infected patients. "Hospital" PPM significantly decreased after tracheotomy only when episodes were compared. Conclusions: While P aeruginosa present in the admission flora caused primary endogenous colonisation/infection during mechanical ventilation on the PICU, S aureus not carried in the throat was responsible for the exogenous colonisation/infection once the patients had a tracheotomy. This is in sharp contrast to adult studies where exogenous infections are invariably caused by AGNB. This discrepancy may be explained by chronic underlying conditions such as diabetes, alcoholism, and chronic obstructive pulmonary disease which promote AGNB, whereas the children were recovering following tracheotomy.

Bacterial Isolates from Tracheal Aspirates and their Anti-microbial Susceptibility in Mechanically-Ventilated Children with Pneumonia Admitted to an Urban Critical Care Ward

“…Our isolated bacterial agents significantly differ from the common bacterial etiology of pneumonia in this age group of children [24,25]. High proportion of children with severe malnutrition (62%), a common co-morbidity of pneumonia and diarrhea in developing countries may be a factor that explains our observation- [26] -the etiology of pneumonia in under-five children is different in such children compared to those without severe malnutrition [9,27].…”

Description of Respiratory Microbiology of Children With Long-Term Tracheostomies

“…1,2,6 However, there are no studies describing the relationship between the length of time with tracheostomy and the spectrum of bacterial growth. Understanding the spectrum of bacteria growth as it compares with time with In contrast to earlier studies describing the respiratory microbiology in subjects with tracheostomies, MRSA was isolated in over half of the study population.…”

Antibiotic Resistance Pattern of Bacterial Isolates from Post- Tracheostomised Patients Attending Tertiary Care Hospital in Nepal

“…and members of Enterobacteriaceae are the frequently encountered infection causing bacteria. However, others like Streptococcus pneumoniae, Moraxella catarrhalis, Haemophilus influenzae, and methicillin sensitive S. aureus also colonise and infect the lower respiratory tract (Ionas et al 2001, Morar et al 2002, Erdem et al 2008. This work was undertaken to assess the antibiotic susceptibility of bacteria isolated from samples associated with tracheostomised patients.…”