Surgical site infection (SSI) is a common, generic postoperative event that causes considerable morbidity but seldom leads to death. Surveillance of SSI is an important infection control activity [
The study was carried out prospectively in the Department of Microbiology and Department of Obstetrics and Gynaecology, Lady Hardinge Medical College and Smt. Sucheta Kriplani Hospital, New Delhi, from November 2008 to March 2010. The study protocol was approved by institutional ethical committee.
500 consecutive patients undergoing emergency/elective LSCS were included in the study irrespective of the indication. At this hospital more than 10,000 deliveries are conducted in a year. SSI rate has been found to be between 15 and 20% by institutional infection control team. Assuming 15% as the basic percentage of development of surgical site infections in postcaesarean patients requesting a 95% confidence interval for the proportion with width no higher than 15% and power of 90%, the minimum sample size needed is 491. A conservative estimate gave a minimum sample size as 500. The patients were assessed postoperatively. Informed consent was taken from every patient enrolled in the study. None of the patients declined to be part of the study. Surgical wound was inspected at the time of first dressing and daily thereafter till discharge of the patient and then all patients were followed up in postnatal clinic till the 30th postoperative day. All patients who developed SSI following surgery were included as cases. All patients who underwent LSCS but did not develop SSI after 30 days were included in the control group. Data was collected from every patient regarding the various risk factors and demographic details by means of a detailed questionnaire.
Surgical site infection was detected on the basis of the criteria given in the modified CDC definition, 1992 [
Purulent discharge was collected from the surgical incision site 48 hours postoperatively with sterile cotton swabs. Thereafter sample was collected every 48 hours till the patient was discharged. Blood sample for blood culture was collected as and when the possibility of septicemia or bacteremia as suggested by the presence of fever, shock, or other signs and symptoms of sepsis associated with the surgical wound was taken a note of. The bacterial isolates obtained were identified as per standard identification procedures [
Antibiotic susceptibility of the incriminated organism was done using standard disc diffusion method as per Clinical Laboratory Standards Institute (CLSI) guidelines [
Data was recorded on a predesigned study questionnaire and managed on an excel spreadsheet. Quantitative variables were assessed for approximate normal distribution and summarized as mean and standard deviation. Categorical variables were summarized by frequency (percentage). Association of each of the potential risk factors with infection as the study outcome was assessed using Pearson’s chi-square test. Comparison of quantitative data was done through Student’s
500 patients included in the study were in the age group 18 years to more than 30 years. The mean age of patients who underwent LSCS was
102 patients out of 500 were found to have infection at the surgical site during their stay in the hospital within 7 days of surgery. 19 patients with surgical site infection were detected by postdischarge surveillance. Thus SSIs were identified in 121 (24.2%) women who underwent LSCS. Table
Isolation of various pathogens causing surgical site infections.
Organisms isolated | Number |
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21 (16.4%) |
Coagulase negative |
6 (4.68%) |
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4 (3.12%) |
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24 (18.75%) |
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19 (14.8%) |
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4 (3.12%) |
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1 (0.78%) |
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8 (6.25%) |
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41 (32.03%) |
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Total isolates | 128 |
(a) Resistance pattern in Gram-positive organisms (in %). (b) Resistance pattern in Gram-negative organisms (in %).
Org. | V | P | M | E | At | C | T | G | Co | Cp | Cu | Ac | Am |
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0 | 66.7 | 23.8 | 15.8 | 14.28 | 66.67 | 28.6 | 25 | 44.4 | 56.25 | 64.3 | 35.7 | 46.7 |
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0 | 50 | — | 100 | 0 | 0 | 0 | 66.7 | 50 | 100 | 0 | 0% | 0 |
CONS | 0 | 16.6 | — | 0 | 16.67 | 0 | 0 | 0 | 0 | 60 | 100 | 60 | 66.67 |
V: vancomycin, P: penicillin, E: erythromycin, At: azithromycin, C: chloramphenicol, T: tetracycline, G: gentamicin, Co: cotrimoxazole, Cp: cephalexin, Ac: amoxicillin-clavulanic acid, and Am: amoxicillin.
Org. | Ak | Cf | Ci | Ce | Co | As | A | I | Ac | Nt | Sc | Pb | Ca | Ao |
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14.28 | 12.5 | 20.8 | 14.28 | 61.9 | 50 | 64.7 | 0 | 38.5 | 33.3 | 0 | 0 | 0 | 60 |
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16.67 | 16.67 | 33.3 | 0 | 72.2 | 5.5 | — | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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25 | 0 | 75 | 0 | 50 | 0 | 66.7 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 100 | 100 |
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0 | 14.28 | 14.28 | 100 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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36.58 | 31.7 | 68.29 | 81.8 | 67.6 | 9.3 | 91.67 | 0 | 0 | 0 | 9 | 20 | 18.7 | 50 |
Ak: amikacin, Cf: ciprofloxacin, Ci: ceftriaxone, Co: cotrimoxazole, As: ampicillin-sulbactam, A: ampicillin, I: imipenem, Ac: amoxicillin-clavulanic acid, Nt: netilmicin, Sc: sparfloxacin, Pb: polymyxin b, Ca: ceftazidime, and Ao: aztreonam.
Risk factor analysis of surgical site infections following LSCS.
Risk factor present | SSI present (out of 121) | SSI absent (out of 379) |
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Emergency procedure | 96 (79.3) | 319 (84.1) | <0.05 |
BMI > 25 | 21 (17.3) | 17 (4.5) | <0.05 |
Prolonged preop. hospital stay (3.11 ± 4.05 days) | 17 (14.1) | 34 (8.9) | <0.05 |
Prolonged total duration of stay after surgery (13.08 ± 4.71 days) | 8 (6.6) | 7 (1.8) | <0.05 |
Vertical skin incision | 24 (19.8) | 28 (7.4) | <0.05 |
PROM > 24 hrs (22.94 ± 2.4 hrs) | 31 (25.6) | 48 (12.7) | <0.05 |
Failure of timely antibiotic prophylaxis | 71 (58.7) | 40 (10.5) | <0.05 |
Preexisting medical illness | 5 (4.1) | 4 (1.1) | <0.05 |
Intraoperative blood transfusion | 17 (14) | 30 (7.9) | <0.05 |
Hb < 11 g% (10.43 ± 2.4) | 52 (43) | 121 (31.9) | >0.05 |
P/V > 3 | 33 (27.2) | 112 (29.5) | >0.05 |
General anaesthesia | 3 (2.5) | 4 (1) | >0.05 |
By multivariate logistic regression premature rupture of membrane (PROM), antibiotics given earlier than 2 hours and increased duration of stay in the hospital were found to be significant. It was interpreted that PROM > 24 hrs is likely to increase the chances of infection by 182.9% (odds ratio = 2.829,
Besides increase in morbidity and mortality, nosocomial infections prolong the hospital stay of patients and increase bed occupancy rate. Also, 7–12% of hospitalized patients end up with hospital acquired infections globally with more than 1.4 million people suffering from infectious complications acquired in the hospital [
The infection rate in the present study was 24.2% including postdischarge surveillance and compares favorably with other reported rates ranging from 2.5 to 41.9% [
Multivariate logistic regression of significant risk factors.
Variables in the equation | |||||||
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S.E. |
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Odds ratio | 95.0% C.I. for odds ratio | |||
Lower | Upper | ||||||
Step 1a | Duration_Hospital_Stay | 0.563 |
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Constant |
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Step 2b | Duration_Hospital_Stay |
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Preop_Stay_2(1) |
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Constant |
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Step 3c | Antibiotic_2(1) |
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Duration_Hospital_Stay |
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Preop_Stay_2(1) |
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Constant |
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Step 4d | PROM_24 hrs(1) |
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Antibiotic_2(1) |
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Duration_Hospital_Stay |
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Preop_Stay_2(1) |
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Constant |
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aVariable(s) entered on step 1: Duration_Hospital_Stay.
bVariable(s) entered on step 2: Preop_Stay_2.
cVariable(s) entered on step 3: Antibiotic_2.
dVariable(s) entered on step 4: PROM_24 hrs.
The incidence of caesarean section has dramatically increased in modern medicine and is attributed to many maternal and fetal factors. In the present study, out of 500 patients, 83.4% women underwent emergency LSCS and the rest were electively operated. Emergency LSCS predisposes more to SSI as compared to elective surgery [
Body mass index of more than 25 has been shown to affect the outcome of surgery [
Patients with anaemia were seen to be more prone to SSI. Anaemia diminishes resistance to infection and is frequently associated with puerperal sepsis. Preoperative anaemia is an important predictor of infection and has been proved by several other studies [
Premature rupture of membranes is associated with the largest bacterial inoculum and liquor gets infected and infection supervenes [
The surgeon may choose either a vertical or a transverse skin incision. Vertical incision may be infraumbilical midline or paramedian. Transverse, modified Pfannenstiel incision is made 3 cm above the symphysis pubis. A transverse incision has less chance of wound dehiscence [
Antibiotic prophylaxis in surgical patients has always been a matter of debate. For prophylactic antibiotic the current recommendation states that the parenteral antibiotic must be given within 2 hours of incision so as to attain high tissue and serum levels during surgery [
Shapiro et al. reported that with each hour of surgery the infection rate almost doubles [
A prolonged preoperative stay with exposure to hospital environment, its ubiquitous diagnostic procedures, therapies, and microflora, including multidrug resistant organisms, have been shown to increase the rate of SSI [
Several studies have reported an increased SSI rate in patients operated under general anaesthesia as compared to patients operated under regional anaesthesia [
Patients with multiple per vaginal examinations were not seen to be more predisposed to SSI and were contradictory to studies that have proved this association [
Lilani et al. found that mean postoperative stay of patients who developed infection was almost 4 times (24.82 days) as compared to patients who did not develop SSI, where mean postoperative stay was 6.19 days [
Patients with preexisting illnesses like diabetes mellitus, bronchial asthma, and jaundice or immunocompromised status were seen to be more prone to infection in the present study. Hyperglycaemia has several deleterious effects upon host immune function, most notably on neutrophil function. Poor control of glucose during surgery and in the perioperative period increases the risk of infection and worsens outcome from sepsis. Hypertension, preexisting or pregnancy induced, HIV, and other comorbid states have been associated with SSI in several studies [
The relationship between blood products and SSIs has been a matter of debate for more than two decades. Several studies have supported the association between the use of blood products and the development of postoperative surgical site infections. Allogeneic blood products have immunomodulatory effects that may increase the risk of nosocomial infections [
Common causative organisms leading to post-LSCS SSI include Gram-negative bacteria, anaerobes, and
Polymicrobial etiology was found in 7 out of 121 SSIs identified. Lilani et al. found a polymicrobial etiology in 2 out of 7 SSIs. One of the most prevalent bacteria isolated was
To conclude a proper assessment of risk factors that predispose to SSI and their modification may help in reduction of SSI rates. Also, frequent antimicrobial audit and qualitative research could give an insight into the current antibiotic prescription practices and the factors affecting these practices.