A prospective observational study was conducted in the Microbiology Laboratory at Tertiary Care Hospital, for a period of two years from January 2018–December 2019. Institutional Ethical Clearance was obtained (KAMSRC/IEC/17/2017). Informed consent was obtained from the patients to use their clinical information for the study.

Urine specimen received from the patients, were inoculated by semi-quantitative method on chromogenic agar (CPSID, bioMerieux, France). The plates were incubated at 37°C for 24 hours. A growth of an isolate with more than 1 lac Colony Forming Units per milliliter (>10⁵ CFU/mL) of urine was considered as significant bacteriuria [10]. Two sets FA plus (resin aerobic) and FN plus (resin anaerobic) of Bact/Alert blood cultures (bioMerieux, USA) were received from each patient. The bottles were loaded into BacT/Alert system and incubated at 37°C for five days. The samples flagged positive were unloaded from the system and subcultured on blood agar and chromogenic agar. The plates were incubated at 37°C for 24 hours. Any amount of growth of pathogenic bacteria on the plates was considered as significant [10].

All patients with simultaneously positive urine and blood cultures with an identical bacterial isolate were included in the study. Repeat isolates from the same patient were excluded from the study. The isolates were identified by VITEK 2 system (bioMerieux, France) using Identification cards for GNB (ID GN) (for GNBs) and Identification cards for GPC (ID GP) cards (for Gram Positive Cocci (GPCs) were used. Antimicrobial susceptibility testing was performed on the isolates on the VITEK2 system using the AST 628 (for GPCs) and AST 280 and 281 (for GNBs). The classes of antibiotics tested against GNB were Cephalosporins (3^rd and 4^th generation), Carbapenems, Polymyxins, Aminoglycosides, Quinolones and Beta lactam-Beta lactamase inhibitor combinations [11]. For GPCs, the antibiotic classes were Beta lactams, Aminoglycosides, Macrolides, Quinolones, Glycopeptides and Tetracyclines [11]. Multidrug resistance was documented in isolates showing resistance to more than three classes of antibiotics [12]. The details of clinical presentation, antibiotic therapy and other relevant information such as CRP (latex CRP Mono Reagent, Life labs, India) and PCT (Chemiluminescence Beckman Coulter, USA) values were recorded. The severity of sepsis was correlated with the levels of the proinflammatory markers, CRP (>100 mg/L) and PCT (>10 ng/mL). The levels of PCT were graded as mild or local bacterial infection (<0.5 ng/mL), SIRS (0.5-1.9 ng/mL), Sepsis (2-10 ng/mL) and severe sepsis (>10 ng/mL) [13].

Percentages were calculated using Microsoft office excel 2013.

Out of the total 4033 urine cultures obtained from suspected UTI patients during the study period, 1402 (34.76%) had significant bacteriuria. Out of 1402 patients, 53 (3.78%) patients also had positive blood cultures with the same organism(s) and hence fulfilled the definition of urosepsis. These 53 patients were included in the study for further analysis. The mean age of the patients was 63.92 years. [Table/Fig-1] shows age and sex distribution of the patients. Of these 53 patients, 37 (69.8%) patients were >60 years of age. The male to female distribution was 1:1.12. (25 Males and 28 Females). Common risk factors for developing urosepsis is shown in [Table/Fig-2]. Out of the 53 patients, 43.4% (23/53) had more than one of the risk factors associated with severe sepsis and poor prognosis.

All 53 patients had a monomicrobial infection (51 GNB and 2 Enterococcus). [Table/Fig-3] shows the distribution of the isolates and [Table/Fig-4] shows the antibiotic susceptibility profile of the GNB. There was a 52.94% (27/51) multidrug resistance (Carbapenem resistance) among GNB isolates. Of the 51 GNB isolates, Enterobacteriaceae isolates were 49 (96.08%) and among these, E. coli was the commonest isolate (43/49, 87.75%). Of the total 43 E. coli isolates, 4/43 (9.3%) were only ESBL producers and 23/43 (53.49%) were ESBL and Carbapenemase producers. Of the total 6 K.pneumoniae isolates, 1/6 (16.67%) was only ESBL producer and 3/6 (50%) were ESBL and Carbapenemase producers.

Out of the 53 patients, 75.5% (40/53) progressed to severe sepsis leading to septic shock and multi-organ failure and of which 26/40 (65%) had a fatal outcome {20/26 (77%) females and 6/26 (23%) males}. Severe sepsis and high mortality of 84.6% (22/26), were associated with resistant phenotypes (ESBL and Carbapenemases producers {E.coli (23) and Klebsiellapneumonia (3)}. Of the 2 Pseudomonas aeruginosa isolates, 1 isolate showed resistance to carbapenems. Both these patients with Pseudomonas aeruginosa infection had severe sepsis and a fatal outcome with significant levels of proinflammatory markers (PCT and CRP). In all, there were 2 Enterococcus isolates and both were resistant to Beta lactams and Macrolides but susceptible to vancomycin, teicoplanin and linezolid. Both these patients succumbed to the sepsis with significant levels of proinflammatory markers (PCT and CRP). In the present study, as shown in [Table/Fig-5], 22.6% (12/53) had PCT values 2-10 ng/mL (Sepsis) and 28/53 patients (52.8%) had a value of >10 ng/mL (Severe sepsis). A direct correlation between the PCT levels and poor clinical out-come of the patients in these two groups with severe sepsis was noted with a 65% mortality (26/40). A mean PCT of 17 ng/mL and a mean CRP of 194 mg/L were observed in all the 26 patients who succumbed to the urosepsis. Remainder of the PCT values were <0.5 ng/mL among 8 (15.1%) patients (Local infection) and 0.5-2 ng/mL among 5 (9.5%) patients (SIRS) [Table/Fig-5]. [Table/Fig-6] shows a correlation between the PCT and CRP values with the severity of sepsis. In case of severe sepsis with a PCT of >10 ng/mL, a proportionate increase of serum CRP was noted with an average of 208.3 mg/L. Similarly, in case of sepsis with PCT of 2-10 ng/mL, the mean CRP was 116.4 mg/L. In case of local infection and SIRS, there was no significant rise of CRP, which was 66.1 mg/L and 105.2 mg/L respectively.

[Table/Fig-6]:

PCT vs CRP values.

Urosepsis resulting from complicated UTI in patients with associated underlying risk factors increases morbidity and mortality. The condition can be usually identified early in its course with a basic diagnostic evaluation comprising of risk factor analysis, urine and blood cultures and proinflammatory marker levels for sepsis. Successful management of patients with urosepsis depends on isolating the causative agent and instituting early and specific antibiotic therapy, along with eliminating the infectious foci in the urinary tract [14].

Age of the patients is one of the risk factors. In the present study, 37/53 (69.8%) of the patients were ≥60 years of age with a mean age of 63.92 years, and a mortality of 26/37 (70.3%). Other studies observed a mean age range of 60–83.6 years [15-17], with a mortality rate of 33% [16]. Underlying co-morbid conditions, especially diabetes mellitus has been shown to be associated with development of pyelonephritis and further progressing to urosepsis [15,18]. In the present study, Type 2 DM was a major risk factor among 34/53 (64%) patients. Of the 34 diabetic patients, 32/34 (94.11%) were elderly patients (>60 years), of which 23 patients (71.88%) died of urosepsis.

In the present study, all the 53 cases were of monomicrobial infections with GNB being the predominant isolates 51/53 (96.2%). E. coli was the commonest causative organism, 43/53 (81.1%). The isolation rate of E. coli from other studies were 46.1% [16], 69% [19], 75% [15] and 79% [17]. Multidrug resistant urosepsis is being increasingly reported in various studies [15,19]. This can be attributed to recurrent infections, repeated hospitalisations of the patients and indiscriminate use of antibiotics [20].

PCT is a valuable proinflammatory marker in the diagnosis of bacterial sepsis, determining the severity of sepsis and the duration of antibiotic administration [21]. During an infection, PCT is released up to a thousand fold increase from nearly all tissues and cell types in the host in response to cytokines and bacterial products [22]. Patients with urosepsis and shock also exhibit a significantly higher CRP as compared with urosepsis patients without shock [22-24]. A direct correlation between the levels of PCT and CRP in sepsis and septic shock and mortality was also documented by Brunkhorst FM et al., [22].

In the present study, 40/53 (75.5%) patients progressed to severe sepsis leading to septic shock and multi-organ failure. A mean PCT of 17 ng/mL and a mean CRP of 194 mg/L were observed in all the 26/53 patients who succumbed to the urosepsis, in the present study. The values were low among the survivors, as was also documented by another Indian study (PCT of 12 ng/mL) [23]. and the mortality rate of the patients associated with these resistant isolates was 22/26 (84.6%) [23,24].

There is high mortality rate associated with Multidrug resistant organisms (MDROs) for which a combination therapy of carbapenem plus a Polymyxin B would be effective. Similar studies done on MDROs causing blood stream infections showed a 2-3 fold increase in mortality rate and treatment failure [25,26]. To decrease the mortality rate among MDROs various studies [27,28], have shown effective therapy in such cases to be a combination therapy with Carbapenem plus a Polymyxin B compared to monotherapy.

This study had certain limitations. There was no control group, (UTI with negative blood cultures) to compare the risk factors and values of the biomarkers which can further improve the diagnosis for the clinicians in order to treat patients on risk.

Early recognition of symptoms followed by accurate diagnosis and early goal directed therapy is essential to decrease morbidity and mortality from urosepsis. Patients with existing co-morbid conditions must be educated on the possible risk of UTI leading to urosepsis. They must be advised to seek early intervention in order to avoid poor outcome. A multidisciplinary team including microbiologists, surgeons, infectious disease physicians and radiologists with a coordinated effort is essential for a favourable outcome.