Table 2. Characteristics of patients with invasive non-typhoidal Salmonella infections among malaria vaccine trial (vaccine trial), central nervous system infection study (CNS study), and International Emerging Infections Program (surveillance program) participants during 2009–2014, Siaya county, Kenya.
| Characteristics | Study | Ceftriaxone-resistant infection n/N (%) | Ceftriaxone-susceptible infection n/N (%) | Odds ratioa (95% confidence interval) |
|---|---|---|---|---|
| Number of invasive NTS infection cases | Vaccine trial | 16/90 (18) | 74/90 (82) | |
| CNS study | 16/18 (89) | 2/18 (11) | ||
| Surveillance program | 11/178 (6) | 167/178 (94) | ||
| Demographics | ||||
| Age in months, median (range) | Vaccine trialb | 35 (4–53) | 15 (2–47) | |
| CNS study | 16 (3–62) | 15 (2–28) | ||
| Surveillance program | 42 (18–437) | 50 (4–918) | ||
| Male gender | Vaccine trial | 6/16 (38) | 35/74 (47) | 0.7(0.2–2.0) |
| CNS study | 10/16 (63) | 0/2 (0) | 8.1(0.3–196.2) | |
| Surveillance program | 6/11 (55) | 78/167 (47) | 1.4(0.4–4.7) | |
| Host and maternal factors | ||||
| HIV positivec | Vaccine trial | 2/16 (13) | 7/70 (10) | 1.3(0.2–6.9) |
| Has an HIV-positive mother | Vaccine trial | 9/16 (56) | 19/74 (26) | 3.7(1.2–11.4) |
| Had malaria within 2 weeks before invasive NTS infection diagnosis | Vaccine trial | 10/16 (63) | 46/74 (62) | 1.0(0.3–3.1) |
| Had malaria at the time of invasive NTS infection diagnosisc | Vaccine trial | 8/16 (50) | 37/74 (50) | 1.0(0.3–3.0) |
| Surveillance program | 3/5 (60) | 14/49 (29) | 3.8(0.6–24.9) | |
| Exposure to antimicrobials before visiting a clinic/hospital | ||||
| Took antibiotics before arriving to hospitalc | CNS study | 5/9 (56) | 1/1 (100) | 0.4(0.0–12.6) |
| Taken a medication for this illness | Surveillance program | 5/11 (45) | 85/167 (51) | 0.8(0.2–2.7) |
| Sulfadoxine/pyrimethaminec | Surveillance program | 0/4 (0) | 2/75 (3) | 3.3(0.1–78.7) |
| Trimethoprim-sulfamethoxazolec | Surveillance program | 2/4 (50) | 7/74(9) | 9.6(1.2–78.9) |
| Penicillinc | Surveillance program | 0/4 (0) | 8/76 (11) | 0.9(0.0–18.1) |
| Other antimicrobialsc | Surveillance program | 0/4 (0) | 3/74 (4) | 2.3(0.1–51.0) |
| Clinical history and symptoms | ||||
| Feverc | CNS study | 14/16 (88) | 2/2 (100) | 1.2(0.0–32.1) |
| Surveillance program | 11/11 (100) | 157/166 (95) | 1.4(0.1–25.4) | |
| Temperature in Celsius, median (range) c | Vaccine trial | 38 (36–41) | 38 (35–41) | |
| CNS study | 38 (36–40) | 39 (39–39) | ||
| Surveillance program | 39 (37–40) | 39 (35–41) | ||
| Stiff neckc | CNS study | 7/15 (47) | 1/2 (50) | 0.9(0.0–16.7) |
| Diarrheac | Vaccine trial | 8/15 (53) | 34/73 (47) | 1.3(0.4–4.0) |
| CNS study | 6/14 (43) | 2/2 (100) | 0.2(0.0–3.8) | |
| Surveillance program | 0/11 (0) | 44/166 (27) | 0.1(0.0–2.1) | |
| Vomitingc | Surveillance program | 1/11 (9) | 48/166 (29) | 0.2(0.0–2.0) |
| Outcome | ||||
| Admitted to hospitalc | Surveillance program | 5/11 (45) | 49/166 (30) | 2.0(0.6–6.8) |
| Duration of hospitalization, days (median, range) c | Surveillance program | 3 (2–7) | 3 (0–9) | |
| Discharged without sequelaec | Surveillance program | 4/4 (100) | 46/49 (94) | 0.7(0.0–15.3) |
| Death | Vaccine trial | 0/16 (0) | 3/74 (4) | 0.6(0.0–12.6) |
Data are presented as No. (%) unless otherwise indicated.
CNS, central nervous system.
aCalculated by X2 test or Fisher’s exact test, as appropriate.
bThe older age of patients with ceftriaxone-resistant NTS infection among the vaccine trial participants may have been related to the emergence of resistance relatively late (2013 and 2014) in the study when the participants of this longitudinal study in general have grown older.
cMissing data were excluded from the analyses.