Results
During the study period of 7 years, 307,299 patients were admitted to the various wards of the hospital. Of these stool samples from patients suspected to have CDI by the treating team were sent to our laboratory for C. difficile toxin assay. The study retrospectively looked if specific underlying diseases had any bearing on C. difficile toxin positivity. We thus accessed 2036 patients’ record data scrutinized on the basis of eligibility criteria. CDI was positive in 440 (21.6%) of the 2036 samples tested. Statistically adequate sample power was provided by this large number of patients available and even disease-wise the sample size is ≥ 245. Estimation of sample size was also done considering the association of 50%, 10% error and 95% CI and adjusted for design effect. The estimated sample size thus obtained for this extreme condition is 192. Therapies received by the patients were also reviewed.
Pancreatic disease patients
Of the 340 pancreatic disease patients analyzed in the study, 232 (68.2%) were males and 108 (31.8%) females. The age range of the patients was 10–85 years (mean ± SD: 41 ± 14). There were 327 (96.2%) hospitalized patients, 6 (1.8%) outpatients and 7 (2.0%) patients with hospitalization status unknown. Major antibiotics received by these patients were nitroimidazoles (n = 107), penicillins (n = 88), carbapenems (n = 87), fluoroquinolones (n = 24), cephalosporins (n = 22), polymyxins (n = 11), aminoglycosides (n = 10), oxazolidinones (n = 8) and lincosamides (n = 6). Antifungals and proton pump inhibitors (PPI) were received by 5 each of the patients. However no patient received any form of immunosuppressant drugs or steroid treatment.
Hepatic disease patients
In the patients with liver diseases (n = 245; M:F 188:57) the age ranged from 9 to 83 years (mean ± SD: 45 ± 14). There were 233 (95%) hospitalized patients, 6 (2.5%) outpatients and 6 (2.5%) patients whose hospitalization status was not known. Major antibiotics received by these patients were penicillins (n = 35), cephalosporins (n = 19), nitroimidazoles (n = 17), polymyxins (n = 11), carbapenems (n = 10), fluoroquinolones (n = 9), oxazolidinones (n = 2) and lincosamides (n = 2). Ten patients received PPI and 4 received immunosuppressants. But no patient received any form of steroid treatment.
Renal disease patients
In the patients with renal disorders (n = 408; M:F 280:128) the age ranged from 10 to 90 years (mean ± SD: 42 ± 16). There were 318 (77.9%) hospitalized patients, 73 (17.9%) outpatients and 17 (4.2%) patients with unknown hospitalization status. Major antibiotic received by these patients were penicillins (n = 107), nitroimidazoles (n = 98), fluoroquinolones (n = 79), glycopeptides (n = 44), cephalosporins (n = 39), carbapenems (n = 29), aminoglycosides (n = 8), lincosamides and polymyxins (n = 5 each) and oxazolidinones (n = 2). Patients receiving antifungals were 3, antivirals 2 and antiprotozoal 1. Immunosuppressants were received by 19 and steroid treatment by 9 of the patients.
Malignancy group patients
In the patients with malignancies (n = 517; M:F 350:167) the age ranged from 3 to 86 years (mean ± SD: 34 ± 23). There were 487 (94.2%) hospitalized patients, 20 (3.9%) outpatients and 10 (1.9%) patients with hospitalization status unknown. Major antibiotics received by these patients were carbapenems (n = 42), cephalosporins (n = 38), glycopeptides (n = 24), penicillins (n = 22), nitroimidazoles (n = 16), fluoroquinolones and aminoglycosides (n = 13 each), polymyxins (n = 10), oxazolidinones and lincosamides (n = 2 each). Antifungals were received by 5, antiviral by 13, steroids by 7 and immunosuppressant by a lone patient.
Miscellaneous disease patients
There were 526 patients (M:F 325:201) who did not have IBD or any other above grouped co-morbidities. The age of the patients ranged from 3 to 103 years (mean ± SD: 41 ± 19). There were 432 (82.2%) hospitalized patients, 77 (14.6%) out patients and 17 (3.2%) patients with hospitalization status unknown. Major antibiotic received by these patients were penicillins (n = 55), glycopeptides (n = 53), nitroimidazole (n = 51), cephalosporins (n = 49), fluoroquinolones (n = 26), carbapenems (n = 18), aminoglycosides (n = 16), lincosamides and polymyxins (n = 4) and oxazolidinones (n = 3). Other drugs received by the patients were antifungals (n = 8), antivirals (n = 16), antiprotozoals (n = 2), PPI (n = 45), steroids (n = 38) and immunosuppressants (n = 16).
Association of C. difficile toxin status and underlying disease conditions
We have also performed the logistic regression analysis to cross check and the result is not different as explained through stratified tabular results. Logistic regression with C. difficile versus disease conditions provides p-value < 0.05 only for patients with pancreatic diseases. Whereas adjusted p-value using rest of variables have similar findings. The odd ratio and adjusted odd ratio are 1.77 (1.29, 2.42) and 1.91 (1.35, 2.67). In addition bloody diarrhea is also reported significant (p-value < 0.05) irrespective to underlying diseases condition.
Association between patients’
C. difficile toxin status and underlying disease conditions, irrespective to all observed factors is depicted in Table
1 and found to be significant (p < 0.05). Distribution of patients with underlying disease conditions highlighted that proportion of hepatic disease patients was the smallest (12.0%) while those with miscellaneous disease was the highest (25.9%). Chi-square p-value of < 0.05 explained that the underlying disease condition is a risk factor for
C. difficile toxin status and further post hoc analysis showed that pancreatic disease group was significant (p < 0.05) in association with the other underlying disease conditions. To comprehend the variation based on age groups, the patients were divided into four groups i.e. (i) < 20 years (ii) 20 to < 40 years (iii) 40 to < 60 years (iv) 60 years and above. Association of
C. difficile toxin status with gender, age groups and antibiotic receipt, irrespective to underlying disease conditions (Table
2) was not found to be significant (p > 0.05).
Table 1
Association between patients’ CDT status and underlying disease condition irrespective to all observed factors
Pancreatic diseases | 340 (16.7) | 104 (30.6) | 236 (69.4) | < 0.05* |
Hepatic diseases | 245 (12.0) | 48 (19.6) | 197 (80.4) |
Renal diseases | 408 (20.0) | 73 (17.9) | 335 (82.1) |
Malignancies | 517 (25.4) | 110 (21.3) | 407 (78.7) |
Miscellaneous diseases | 526 (25.9) | 105 (20) | 421 (80) |
Total | 2036 (100) | 440 (21.6) | 1596 (78.4) | |
Post Hoc analysis* Adjusted p-value* | Pancreatic diseases | Hepatic diseases | < 0.05* |
Renal diseases |
Malignancies |
Miscellaneous diseases |
Hepatic diseases | Renal diseases | 0.71 |
Miscellaneous diseases | 0.92 |
Malignancies | Hepatic diseases | 0.71 |
Renal diseases | 0.42 |
Miscellaneous diseases | 0.71 |
Miscellaneous diseases | Renal diseases | 0.71 |
Table 2
Association of CDT status with gender, age and antibiotic receipt, irrespective to underlying diseases conditions
Gender |
Male | 1375 (67.5) | 1073 (78.0) | 302 (22.0) | 0.617 |
Female | 661 (32.5) | 523 (79.1) | 138 (20.9) |
Total | 2036 (100) | 1596 (78.4) | 440 (21.6) | |
Age groups in years |
2 to < 20 | 294 (14.4) | 227 (14.2) | 67 (15.2) | 0.773 |
20 to < 40 | 668 (32.8) | 522 (32.7) | 146 (33.2) |
40 to < 60 | 729 (35.8) | 580 (36.4) | 149 (33.9) |
60 and above | 345 (17) | 267 (16.7) | 78 (17.7) |
Total | 2036 (100) | 1596 (78.4) | 440 (21.6) | |
Antibiotics receipt |
Nil | 437 (21.5) | 352 (80.6) | 85 (19.4) | 0.461 |
Single | 689 (33.8) | 535 (77.6) | 154 (22.4) |
Multiple | 910 (44.7) | 709 (77.9) | 201 (22.1) |
Total | 2036 (100) | 1596 (78.4) | 440 (21.6) | |
Association between patients’ clinical symptoms and
C. difficile toxin status, irrespective of underlying diseases condition is presented in Table
3 and that between patients’ gender, age groups and antibiotics receipt with underlying disease conditions, irrespective to
C. difficile toxin status in Table
4. Underlying disease conditions irrespective to
C. difficile toxin status are highlighted in Table
5.
Table 3
Association between patients’ symptoms and CDT status, irrespective to underlying diseases condition
Bloody diarrhea | |
Absent | 1912 (93.9) | 1508 (94.5) | 404 (91.8) | 0.05* | |
Present | 124 (6.1) | 88 (5.5) | 36 (8.2) | |
Total | 2036 (100) | 1596 (78.4%) | 440 (21.6%) | | |
Watery diarrhea | |
Absent | 768 (37.7) | 613 (38.4) | 155 (35.2) | 0.25 | |
Present | 1268 (62.3) | 983 (61.6) | 285 (64.8) | |
Total | 2036 (100) | 1596 (78.4%) | 440 (21.6%) | | |
Mucus in stool | |
Absent | 1364 (67.0) | 1065 (66.7) | 299 (68) | 0.67 | |
Present | 672 (33.0) | 531 (33.3) | 141 (32) | |
Total | 2036 (100) | 1596 (78.4%) | 440 (21.6%) | | |
Abdominal pain | |
Absent | 1193 (58.6) | 951 (59.6) | 242 (55) | 0.09 | |
Present | 843 (41.4) | 645 (40.4) | 198 (45) | |
Total | 2036 (100) | 1596 (78.4%) | 440 (21.6%) | | |
Fever | |
Absent | 1174 (57.7) | 922 (57.8) | 252 (57.3) | 0.90 | |
Present | 862 (42.3) | 674 (42.2) | 188 (42.7) | |
Total | 2036 (100) | 1596 (78.4%) | 440 (21.6%) | | |
Frequency | Median (IQR) | 6 (4–8) | 6 (4–8) | Ranksum test | 0.521 |
Duration | Median (IQR) | 3 (2–7) | 3 (2–6) | 0.119 |
Table 4
Association between patients’ characteristics with underlying diseases condition, irrespective to CDT status (n = 2036)
Gender |
Male | 232 (68.2) | 188 (76.7) | 280 (68.6) | 350 (67.7) | 325 (61.8) | < 0.05* |
Female | 108 (31.8) | 57 (23.3) | 128 (31.4) | 167 (32.3) | 201 (38.2) |
Total | 340 (100) | 245 (100) | 408 (100) | 517 (100) | 526 (100) | |
Age groups in years |
2 to < 20 | 12 (3.5) | 5 (2) | 24 (5.9) | 184 (35.6) | 69 (13.1) | < 0.05* |
20 to < 40 | 157 (46.2) | 73 (29.9) | 157 (38.5) | 98 (18.9) | 183 (34.8) |
40 to < 60 | 129 (37.9) | 128 (52.2) | 164 (40.2) | 143 (27.7) | 165 (31.4) |
60 and above | 42 (12.4) | 39 (15.9) | 63 (15.4) | 92 (17.8) | 109 (20.7) |
Total | 340 (100) | 245 (100) | 408 (100) | 517 (100) | 526 (100) | |
Antibiotics received |
Nil | 50 (14.7) | 36 (14.7) | 117 (28.7) | 80 (15.5) | 154 (29.3) | < 0.05* |
Single | 123 (36.2) | 111 (45.3) | 104 (25.5) | 153 (29.6) | 198 (37.6) |
Multiple | 167 (49.1) | 98 (40) | 187 (45.8) | 284 (54.9) | 174 (33.1) |
Total | 340 (100) | 245 (100) | 408 (100) | 517 (100) | 526 (100) | |
Table 5
Association between patients’ clinical symptoms and underlying diseases condition, irrespective to CDT status
Bloody diarrhea | | |
Absent | 324 (95.3) | 236 (96.3) | 389 (95.3) | 484 (93.6) | 479 (91.1) | 0.01* | | |
Present | 16 (4.7) | 9 (3.7) | 19 (4.7) | 33 (6.4) | 47 (8.9) | | |
Watery diarrhea | | |
Absent | 113 (33.2) | 100 (40.8) | 144 (35.3) | 207 (40) | 204 (38.8) | 0.17 | | |
Present | 227 (66.8) | 145 (59.2) | 264 (64.7) | 310 (60) | 322 (61.2) | | |
Mucus in stool | | |
Absent | 190 (55.9) | 165 (67.3) | 299 (73.3) | 355 (68.7) | 355 (67.5) | < 0.05* | | |
Present | 150 (44.1) | 80 (32.7) | 109 (26.7) | 162 (31.3) | 171 (32.5) | | |
Abdominal pain | | |
Absent | 156 (45.9) | 148 (60.4) | 263 (64.5) | 309 (59.8) | 317 (60.3) | < 0.05* | | |
Present | 184 (54.1) | 97 (39.6) | 145 (35.5) | 208 (40.2) | 209 (39.7) | | |
Fever | | |
Absent | 172 (50.6) | 171 (69.8) | 277 (67.9) | 240 (46.4) | 314 (59.7) | < 0.05* | | |
Present | 168 (49.4) | 74 (30.2) | 131 (32.1) | 277 (53.6) | 212 (40.3) | | |
Frequency | Median (IQR) | 5 (4–8) | 6 (5–8) | 6 (4–8) | 5 (4–8) | 5 (4–8) | Kruskal–Wallis test | 0.006* |
Duration | Median (IQR) | 3 (2–10) | 3 (2–5) | 3 (2–5) | 3 (2–4.5) | 5 (3–15) | < 0.001* |
Association between patients’ gender, age groups and antibiotic receipt with underlying disease conditions, respective to
C. difficile toxin status (Table
6) showed significance in relation to male gender (p < 0.05), age 40 to < 60 years (p = 0.03) and receipt of single (p = 0.09) and multiple antibiotics (p = 0.07). But association between patients’ clinical symptoms and CDI respective to underlying diseases conditions (Table
7) was found to be non-significant (p > 0.05) in relation to clinical symptoms. The association of CDI was stratified based on the underlying disease conditions and further on gender, age-group and number of antibiotics used.
Table 6
Association between patients’ characteristics and CDT status infection respective to underlying diseases condition
Gender |
Male |
CDT pos | 302 | 74 | 37 | 54 | 71 | 66 | < 0.05* |
CDT neg | 1073 | 158 | 151 | 226 | 279 | 259 |
Total | 1375 | 232 | 188 | 280 | 350 | 325 | |
Female |
CDT pos | 138 | 30 | 11 | 19 | 39 | 39 | 0.23 |
CDT neg | 523 | 78 | 46 | 109 | 128 | 162 |
Total | 661 | 108 | 57 | 128 | 167 | 201 | |
Age groups in years |
2 to < 20 |
CDT pos | 67 | 5 | 1 | 6 | 40 | 15 | 0.75 |
CDT neg | 227 | 7 | 4 | 18 | 144 | 54 |
Total | 294 | 12 | 5 | 24 | 184 | 69 | |
20 to < 40 |
CDT pos | 149 | 36 | 25 | 24 | 32 | 32 | 0.13 |
CDT neg | 581 | 93 | 103 | 141 | 111 | 133 |
Total | 730 | 129 | 128 | 165 | 143 | 165 | |
40 to < 60 |
CDT pos | 146 | 50 | 13 | 30 | 20 | 33 | 0.03* |
CDT neg | 521 | 107 | 60 | 126 | 78 | 150 |
Total | 667 | 157 | 73 | 156 | 98 | 183 |
60 and above |
CDT pos | 78 | 13 | 9 | 13 | 18 | 25 | 0.82 |
CDT neg | 267 | 29 | 30 | 50 | 74 | 84 |
Total | 345 | 42 | 39 | 63 | 92 | 109 | |
Antibiotics receipt |
Nil | | | | | | | |
CDT pos | 85 | 13 | 8 | 19 | 16 | 29 | 0.80 |
CDT neg | 352 | 37 | 28 | 98 | 64 | 125 |
Total | 437 | 50 | 36 | 117 | 80 | 154 | |
Single |
CDT pos | 154 | 39 | 23 | 16 | 34 | 42 | 0.09 |
CDT neg | 535 | 84 | 88 | 88 | 119 | 156 |
Total | 689 | 123 | 111 | 104 | 153 | 198 | |
Multiple |
CDT pos | 201 | 52 | 17 | 38 | 60 | 34 | 0.07 |
CDT neg | 709 | 115 | 81 | 149 | 224 | 140 |
Total | 910 | 167 | 98 | 187 | 284 | 174 | |
Table 7
Association between patients’ symptoms and CDT status respective to underlying diseases condition (n = 2036)
Bloody diarrhea |
Pos | 6 | 4 | 4 | 7 | 15 | 0.65 |
Neg | 10 | 5 | 15 | 26 | 32 |
Total | 16 | 9 | 19 | 33 | 47 | |
Watery diarrhea |
Pos | 69 | 30 | 50 | 65 | 71 | 0.06 |
Neg | 158 | 115 | 214 | 245 | 251 |
Total | 227 | 145 | 264 | 310 | 322 | |
Mucus in stool |
Pos | 42 | 17 | 20 | 31 | 31 | 0.29 |
Neg | 108 | 63 | 89 | 131 | 140 |
Total | 150 | 80 | 109 | 162 | 171 | |
Abdominal pain |
Pos | 55 | 28 | 27 | 49 | 39 | 0.07 |
Neg | 129 | 69 | 118 | 159 | 170 |
Total | 184 | 97 | 145 | 208 | 209 | |
Fever |
Pos | 49 | 17 | 23 | 58 | 41 | 0.18 |
Neg | 119 | 57 | 108 | 219 | 171 |
Total | 168 | 74 | 131 | 277 | 212 | |
Discussion
Clostridium difficile is largely spread by the feco-oral route and it is believed that underlying disease is a risk factor for CDI development [
5]. The reduction of risk factors upon exposure to microbes is important to control CDI [
8]. Though there are several co-morbidities associated with CDI, the available studies are mostly related to IBD [
6,
9,
10] malignancy [
11‐
13] or solid organ transplantation [
14,
15]. In the present study we evaluated CDI in patients with specific underlying co-morbidities like pancreatic, hepatic and renal diseases and patients with malignancies and compared them with patients having other miscellaneous conditions.
In general, male gender was found to be strongly associated with various underlying diseases compared to females.
C. difficile toxin positivity was not found to be significantly associated with the clinical symptoms and with the use of antibiotics in all the underlying disease groups. In an earlier study involving 3044 patients with suspected CDI, Vaishnavi et al. [
7] found that fever (41%) was the most significant clinical symptom present, followed by abdominal pain (37.9%) in
C. difficile toxin positive cases and was highly associated with renal diseases (20.8%), hepatic disorders (18.5%) and cancers (17.6%). In the present study
C. difficile toxin status irrespective to the underlying diseases was neither dependent on gender, age-group or the number of antibiotics used.
The association of CDI based on 2036 patients’ data was computed 21.6% which is not the correct representation because the distribution of CDI prevalence depends on the underlying co-morbidities of the patients. The association of CDI stratified based on the underlying disease condition and further based on gender, age-groups and the number of antibiotics used showed highest association (30.6%) in pancreatic disease group and lowest in the renal disease group (17.9%). It was thus clear that pancreatic disease condition is a risk factor for CDI as compared to other underlying diseases. Similar condition was noted for association of CDI for pancreatic disease group when stratified by patients’ clinical symptoms. Association between patients’ gender, age and antibiotics received with underlying diseases condition, respective to C. difficile toxin status showed significance in relation to male gender (p < 0.05), in age 40 to < 60 years (p = 0.03) and receipt of single (p = 0.09) and multiple antibiotics (p = 0.07).
Clostridium difficile infection is commonly reported as nosocomial [
3] and community acquired [
4] with 22% hospital acquired cases in liver transplant patients [
16]. The Canadian Nosocomial Infection Surveillance Program reported that of 1430 cases 62 (4%) CDI patients had underlying hepatic disease [
17]. Musa et al. [
18] reported CDI to be significantly more common amongst cirrhotics with hepatorenal syndrome. Bajaj et al. [
19] observed that CDI independently increased the mortality in cirrhotic hospitalized patients. In the present study,
C. difficile toxin was positive in 19.6% of the hepatic patients and the use of antibiotics in this group was found to be highly significant compared to the control miscellaneous disease group.
Keven et al. [
14] in a 4 year study period reported 39 (5.5%) CDI cases among 600 kidney and 102 pancreas–kidney allograft transplants, with the latter patients having a slightly higher incidence of CDI than recipients of kidney alone. Arrich et al. [
20] described CDI in an 82 year old man with acute renal failure. Eui et al. [
21] retrospectively (2004–2008) investigated 85 CDI patients and reported a highly significant difference in chronic kidney disease prevalence between CDI and non-CDI patients, suggesting that chronic kidney disease as an independent risk factor for CDI development. Several other workers have also reported that patients with chronic kidney diseases have a higher risk of CDI and rise in nosocomial morbidity and mortality [
22,
23]. In the present study in patients with renal disease,
C. difficile toxin was positive in 17.9% of them and the duration of diarrhea was also significant compared to other co-morbid groups, except the miscellaneous disease group which was similar to the renal group.
There is hardly any literature available relating CDI with pancreatic diseases. In the present study, C. difficile toxin positivity (30.6%) in the pancreatic disease group was found to be highly significant compared to all the other specific groups (malignancies, renal and hepatic diseases) as well as the control patients. The use of antibiotics was also found to be significant in the pancreatic disease patients compared to those in the renal disease group and the control miscellaneous disease patients.
Patients with hematological malignancies [
11,
13,
24,
25], post-transplant [
26] post-chemotherapy patients [
27,
28] and those with solid cancers [
15,
29] can be predominantly vulnerable to CDI. This is due to the presence of multiple risk factors for CDI, which include extended hospital stays, exposure to multiple antibiotics and repeated cycles of chemotherapy. Gastrointestinal mucosal damage occurs from conditioning regimen/radiation or graft-versus-host disease of the gastrointestinal tract [
30], and serve as independent risk factors for the development of CDI [
5,
31]. Receiving antibiotics in addition can further increase the risk of acquiring CDI. In the present study the use of antibiotics was found to be highly significant in all the underlying disease groups irrespective of
C. difficile toxin positivity status.
Antibiotics have been established as a risk factor for development of CDI [
5,
32]. Bajaj et al. [
33] reported that in-patient antibiotic use was an independent predictor of CDI in cirrhotic patients. Daniel and Rapose [
34] retrospectively analyzed 100 CDI patients in a community hospital and observed that patients who had taken antibiotics in the previous 6 months constituted 74% of the total study population. In the present study, the use of antibiotics was significant in all the groups with specific underlying diseases. Though we did not find that antibiotic use precipitated CDI, these findings imply that CDI must be ruled out in all diarrheic patients with underlying diseases, as underlying diseases can themselves precipitate CDI. Therefore, these patients should be treated aggressively before the infection becomes complicated.
Reduced gastric acid due to PPI use leads to survival of any ingested
C. difficile [
35‐
37]. Apart from this, PPIs may also suppress the immune response to infection [
38]. One study evaluating the relationship between PPI use and CDI in hepatic disease patients revealed that outpatient PPI use was an independent risk factor for CDI [
39]. Daniel and Rapose [
34] reported that more than 50% patients were on PPIs at the time of admission among 100 CDI patients analyzed with co-morbidities including malignancy (28%), diabetes mellitus (25%) and chronic renal disease (23%). In the present study PPI was used by 45 of the miscellaneous disease patients, 10 of the hepatic patients and 5 of the pancreatic disease patients.
Immunosuppressant medication is often required in certain patients with underlying diseases and is an important risk factor for CDI [
40]. In the present study immunosuppressants were used by 19 of the renal group patients, 16 of the miscellaneous disease group patients, 4 of the hepatic group patients and 1 of the malignancy group patients. Similarly, corticosteroid is also a significant risk factor for patients with underlying disease [
41]. In the present study, 38 patients in the miscellaneous disease group, 9 in the renal group and 7 in the malignancy group received steroids. However, no patient in the pancreatic group or the hepatic group received any form of steroid treatment.
The high association of CDI thus reported in patients with various underlying diseases, particularly the pancreatic group followed by malignancy group, and the considerable rate of severe cases, signifies the requirement for precautionary policies, such as antimicrobial stewardship programs, strict compliance with hand hygiene and environmental decontamination particularly involving this patient group. But despite the routine steps being taken to curb infection with a Hospital Infection Control Committee to constantly check the compliance, actually no decrease in the cases of CDI has been noted. Various factors may account for this. Our institute is a tertiary care hospital catering to the people of the northern region of India, inclusive of Chandigarh, Punjab, Haryana, Himachal Pradesh, Jammu and Kashmir, western parts of Uttar Pradesh and some parts of Rajasthan. Thus patients are referred from other lower centers where implementation of infection surveillance is not available. These patients are on antibiotics previously by the time they reach our hospital. Because of uncontrolled use of antibiotics, the difficulty in controlling antibiotic resistance occurs, despite adequate care being taken in our hospital.
The strength of this study is that this is the first analysis of its kind investigating CDI in underlying disease patients. However there are some limitations of this study. Firstly, the use of ELISA has its own limitations in detecting the toxins, but this method is widely used the world over. Moreover the kits we used had sensitivity up to 98% and specificity up to 92% and the assay was performed by a dedicated trained medical technician and therefore was largely reliable. Though molecular tests can also detect and confirm cases, the use of polymerase chain reaction to detect toxin A or toxin B genes has a potential for false positive results, given its high sensitivity, as PCR will detect even low number of C. difficile organisms transiently present in other hospitalized individuals with no CDI, and thus lead to wrong CDI diagnosis.
Secondly, of all the admitted patients, we had access to only those referred to us for C. difficile toxin assay. If it was surveillance or screening for C. difficile toxin, then the total number of patients with different diseases would be important. But this would have also resulted in tremendous cost to the hospital, which was not feasible in a low budget country.
Thirdly, the cases were not classified according to severity as the data assessment was limited to laboratory details of the patients without access to details on further clinical complications. Thus we had no access to the mortality rate data also. Some data of the patients’ prescriptions could also have been lost due to some likely incomplete records. But, as it is a tertiary care hospital, every effort is routinely made to maintain the demographic and clinical records for future use. However, as this is a preliminary study, further study based on severity classification will be carried out for individual group of diseases.