There were 58 patients with R.terrigena isolated from different culture specimens. Out of those, 12 patients were identified as colonizers, remaining included in the study (see Figure-1). The median age was 61.5 years (IQR=28), with more males than females (60.9 % vs. 39.1%.) The most frequent co-morbid conditions were diabetes mellitus in n=18 (39.1%), followed by chronic kidney disease in n=16 (34.7%) and malignancy in n=11 (23.9) (see table-1). Most patients n= 34 (73.9%) had a previous history of hospitalization (within the past six months), and in the majority, n=24 (52.17%) had at least one hospital admission. 78% patients (n=36) reported antibiotic use in last 6 months. The most commonly used antibiotics were carbapenems in n=26 (56.5%). Also beta-lactam, beta-lactamase inhibitors in n=23 (50%) and glycopeptides in n=20 (43.5).
Almost n=31 (67.4%) of the patients had had a prior culture growing a multidrug-resistant organism in the last six months. The most commonly found organism was carbapenem-resistant Klebsiella pneumonia in n=13 (28.2%), followed by multidrug-resistant Acinetobacter and Pseudomonas aeruginosa n=11 (23.9%) of patients. Approximately n=35 (76.1%), had a urinary catheter in place, and central lines were present in n=22 (47.8%), surgical drains in n=14 (30.4%) , and VP shunt in n=1 (2.2%) of patients. There were 29 patients (63%) with this infection who had a recent history (past six months) of invasive procedures. Of those, n=9 (31%) had undergone skin soft tissue procedures, genitourinary surgeries in n=8 (27.6) cases, n=7 (24.1%) had abdominal procedures, and n=7 (24.1%) had central nervous system interventions.
The most common site of infection was the respiratory tract in n=13 (28.3%), followed by Urinary tract infections n=12 (26%), and bloodstream infections n=12 (26.1%.) (Table 1). Approximately n=21 (45.7%) had respiratory failure, that required mechanical ventilation in n=11 (52.4%), and non-invasive ventilation in n=10 (47.6%). N=17 patients, (37%) were in septic shock shock due to R.terrigena. Of them n=13, (76.5%) required vasopressors and n=4 (23.5%) treated with fluid resuscitation
Monomicrobial growth of Raoultella terrigena was identified from n=26 (56.5%) of culture specimens, and polymicrobial growth was identified from n=20 (43.5%) culture specimens. The most common sources were blood in 32.6%, sputum in 28.3%, and urine in 21.7%. The organism was highly resistant to most of the commonly used antibiotics. Carbapenem resistance was present in 91.3%, colistemethate resistance 65.2%. Tigecycline resistance present in 10.9% (checked in 31 strains) and fosfomycin resistance in 28.3% (checked in 29 strains) (Table-2). In most cases, sensitivities were checked for tigecycline and fosfomycin after they were resistant to colistemethate.
Out of 46 cases, eight patients lost to follow up, and treatment information was not available. The remaining 38 patients, n=31 patients (81.6%) received combination therapy, and n=6 (15.8%) received monotherapy. One patient died before starting treatment. The most frequent combination was carbapenem and colistemethate in n=11 (28.9%), followed by a combination of carbapenem with colistemethate and tigecycline in n=8 (21.1%) (Table-3). In 71.1% cases, the treatment was inappropriate for R-terrigena while the remaining 28.9%, given appropriately. Mortality association with monotherapy was (p= 0.672), and with combination therapy (p= 0.70). Out of n=14 (36.84%) cases in whom repeat cultures for clearance needed, bacteriological clearance was achieved in n=9 (64.2%) cases. There were 23 cases that needed source control of underlying infection. It was achieved in n=12 (52.1%). Two cases (5.3%) relapsed.
The average hospital stay was a median of 11.50 days (IQR=17), with a median of 3 days before positive culture. Approximately n=23 (60.52%) of patients were seriously ill, requiring intensive care unit care with a median ICU stay of 6 days (IQR=7). In-hospital mortality recorded in n=17 (44.7%) patients.
In the subgroup analysis of factors associated with death in R.terrigena infections, it was found that chronic kidney disease (CKD) ((p=.029) and septic shock (p=.005) were significantly associated with mortality. Also, persons with a high (greater or equal to three) Charlson- comorbidity index had increased mortality (p=0.002).