NG outbreaks
Between 2009 and 2011, there were 8 outbreaks: 3 in 2009, 3 in 2010, and 2 in 2011. Between 2009 and 2011, NG outbreaks occurred in 6 of the 19 facilities (32%), with outbreaks occurring in two consecutive years in 2 of the facilities. In all 6 facilities where NG outbreaks occurred, NG prevention measures were implemented the year when the outbreaks occurred. These facilities had a mean capacity of 102 (range: 95 to 120) residents, a median average occupancy rate of 98% (25th percentile, 95%; 75th percentile, 104%), with mean nursing care levels similar to those of all 19 facilities. Of 8 outbreaks, 7 occurred from December to January of the following year and 1 outbreak occurred in February. Six of the 8 outbreaks resulted in restricting the acceptance of new residents, with a median restriction period of 20 days (25th percentile, 13 days; 75th percentile, 38 days); the duration of restriction was not known in one of six outbreaks.
Infected residents
The number of infected residents in each facility is shown in Table 1. From 2009 to 2011, there were 146 infected residents in 6 facilities where NG outbreaks occurred. In the 5 facilities (Facilities A to E) that granted permission to examine patients’ medical records, the clinical course and treatment were investigated for 107 patients (A: 4, B: 41, C: 2, D: 24, E: 36). Of these 107 individuals, 21 (20%) were men, and 86 (81%) were women, with a mean age of 85.4 (range: 68 to 101) years, 42 (39%) could communicate but required assistance in carrying out some activities of daily living (ADL), 58 (54%) had difficulty communicating and required assistance in carrying out all ADL, and 7 (7%) could not communicate and required assistance in carrying out all ADL. NG was diagnosed using a diagnostic kit in 32 (30%) of the patients and on the basis of symptoms only in 75 (70%) of the patients. Among 32 patients diagnosed using a diagnostic kit, 17(53%) had positive.
Symptoms exhibited by infected residents
Of the 107 patients whose records were examined, 106 (99%) presented with vomiting or diarrhea (both vomiting and diarrhea 52 (49%), diarrhea only 37 (35%), vomiting only 17 (16%)). Associated symptoms of some kind were observed in 84 (79%) patients, with some patients presenting with multiple symptoms (decreased appetite 69 (65%), fever of 37.0°C or greater 59 (55%), general malaise 47 (44%), and vomiting of blood 2 (2%)). Median symptom duration for the 107 patients was 4 days (25th percentile, 2 days; 75th percentile, 6 days).
Isolation of infected residents
The number of isolated infected residents is shown in Table 1. The most common isolation method used was to place infected residents in the same room. However, in cases where same-room placement was deemed difficult due to room shortages, divider curtains around the beds were used to set off areas for infected residents. Of the 107 patients, 72 (67.3%) were isolated. Median isolation duration was 4 days (25th percentile, 3 days; 75th percentile, 5 days).
Treatment of infected residents
Of the 107 patients, 81 (76%) received some sort of medication or transfusion. No substantial difference was observed in the characteristics of residents who received or did not receive medication or transfusion (Table 2). A higher proportion of residents receiving medical treatment was isolated than residents not receiving medical treatment (p = 0.008). No other differences were observed between the two groups of residents.
Drugs were administered in one of three ways: intravenously, orally, or as a suppository. Ten (9%) patients administered as a suppository were administered only once during fever. The number of patients receiving drugs, treatment duration, and costs of each drug are presented in Table 3. Treatment was administered intravenously to 67 (63%) patients, orally to 47 (44%) patients, and both intravenously and orally to 33 (31%) patients. Median treatment durations for drugs administered intravenously and orally were 2 and 3 days, respectively. The drug types administered, in order of most to least common, were infusion (67 patients, 63%), antibiotics (30 patients, 28%), antidiarrheals (27 patients, 25%), antipyretic (19 patients, 17%), and antiemetics (17 patients, 16%). The antibiotics administered consisted of new quinolones (21 patients, 70%), macrolides (6 patients, 20%), tetracyclines (2 patients, 3%), penicillins (2 patients, 3%), cephems (2 patients, 3%), and aminoglycosides (1 patient, 1%), with 4 of the 30 patients (13%) being prescribed two types of antibiotics.
The median cost of all drugs administered was USD 4.4, and the median cost of drugs per infected resident per day was USD 2.0. Median drug cost over the entire treatment duration was the highest for antibiotics, at USD 8.6.
Outcomes
Of the 107 patients, 99 (93%) recovered in facility, 1 (1%) died in facility, and 7 (6%) were transferred to hospitals. Of the 7 patients transferred to hospitals, 1 died in hospital.