Children who have developmental disabilities and aggressive or self-injurious behavior are treated in Unit 1. Inpatient capacity is 17, and <5 outpatients are sometimes present during the day for group and individual therapy. The unit employs >100 staff members. Patients require constant supervision and intensive help with activities of daily living.
At the beginning of this investigation, we established outbreak case definitions. We defined confirmed pneumococcal disease as IPD (isolation of S. pneumoniae from a normally sterile site such as blood) or noninvasive (laboratory confirmation of S. pneumoniae from a nonsterile site in the setting of a compatible clinical illness, such as isolation from ear drainage samples from a patient with otitis media). We defined confirmed pneumonia as pneumonia diagnosed by a clinician, using chest radiographs confirmed as showing pneumonia by a radiologist. We defined suspected pneumonia as pneumonia diagnosed by a clinician with no radiologic studies obtained. Cases occurred in Unit 1 staff, patients, and visitors during the study period. We maintained active surveillance through May 1, but no cases occurred after February 23.
To identify risk factors for pneumococcal disease (3
), we abstracted medical records of all Unit 1 patients (n = 30) during November 1, 2010–January 30, 2011. Unit 1 staff members completed questionnaires about respiratory illnesses experienced during December–February. The hospital informed families of then-current Unit 1 patients of the outbreak. Family members or visitors who reported illness were interviewed. All pertinent medical records were reviewed.
We collected available clinical specimens and conducted a survey to identify respiratory pathogens carried by patients and staff (). We collected nasopharyngeal and oropharyngeal calcium alginate swab specimens from then-current Unit 1 patients (n = 16) and staff with ongoing respiratory symptoms (n = 4) during January 29–February 2. For pneumococcal carriage, swab specimens were processed as described (5
). Three pneumococcal isolates were recovered (2 from blood, 1 from ear drainage samples). Swab specimens and isolates underwent specific real-time PCR that targeted the lytA
), PCR-based serotyping (7
), and multilocus sequence type determination (9
). Antibacterial drug susceptibility testing was performed by using broth microdilution (10
). Additional swabs stored in viral transport media were tested by solid-phase real-time PCR on TaqMan Array Cards (Life Technologies, Carlsbad, CA, USA), for 20 additional respiratory pathogen targets (11
Figure 1 Respiratory pathogen carriage survey related to Streptococcus pneumoniae serotype 15A outbreak in a pediatric psychiatric hospital, Rhode Island, USA, December 25, 2010–January 31, 2011, performed on Unit 1 patients (n = 16) and symptomatic staff (more ...)
Twenty patients resided on Unit 1 during December 25, 2010–January 31, 2011 (). Among Unit 1 patients, staff, and visitors, the following cases were identified: 3 confirmed pneumococcal disease, 6 confirmed pneumonia, and 2 suspected pneumonia (). Three case-patients were hospitalized (2 with IPD, 1 with confirmed pneumonia). Among the 20 patients, the cases of 5 (attack rate 25%) met an outbreak case definition (). In addition, 1 staff member had IPD, 1 had confirmed pneumonia, and 1 had suspected pneumonia (, attack rate <3%). These staff members provided direct care to all Unit 1 patients. Three visitors had confirmed pneumonia. Adults (3 staff and 3 visitors) who became ill during the outbreak and for whom ages were available (5 of 6) ranged in age from 27 to 56 years.
Characteristics of 20 psychiatric unit patients during Streptococcus pneumoniae serotype 15A outbreak, Rhode Island, USA, December 25, 2010–January 31, 2011
Figure 2 Epidemic curve of Streptococcus pneumoniae outbreak in a pediatric psychiatric hospital, Rhode Island, USA, December 25, 2010–January 31, 2011, for invasive pneumococcal disease, noninvasive pneumococcal disease, confirmed pneumonia, and suspected (more ...)
Cases, clinical isolates, and results of pneumococcal carriage and respiratory pathogen survey associated with Streptococcus pneumoniae serotype 15A outbreak, Rhode Island, USA, December 25, 2010–January 31, 2011*
All 3 clinical isolates were identified as S. pneumoniae serotype 15A, sequence type 63, () with matching antimicrobial drug susceptibility patterns. Nine (45%) of 20 persons tested carried pneumococcus; of those, 6 (30%) carried serotype 15A. Rhinovirus, Streptococcus pyogenes, and Mycoplasma pneumoniae were additional pathogens most frequently identified by using TaqMan Array Cards (, ).
We assessed Unit 1 infection control practices; in particular, for staff compliance with hand and respiratory hygiene. The hand hygiene audit revealed that staff members had performed hand hygiene in 4 (24%) of 17 instances before patient contact and 11 (79%) of 14 times after patient contact, for an overall compliance of 15 (48%) of 31 opportunities. In addition,, supplies (e.g., gloves) were kept in locked cabinets because of safety concerns. Staff reported that patients, because of their developmental delays, were often unable to appropriately manage their respiratory secretions.
The presence of 6 carriers of serotype 15A on Unit 1 during the carriage survey indicated the potential for continued transmission and disease. The hospital mandated hand and respiratory hygiene training for all Unit 1 staff, administered during February 4–8. We recommended high-dose amoxicillin prophylaxis (90 mg/kg/day divided into 2 doses, maximum of 1,000 mg, for 5 days) for all Unit 1 patients, which began on February 7. After control measures were fully implemented, 1 case of pneumonia was confirmed in a patient’s parent on February 23, but the etiology was not identified. No additional cases occurred among Unit 1 patients and staff members during the subsequent 3 months.