Trop Doct 2008;38:233-235
doi:10.1258/td.2008.070395
© 2008 Royal Society of Medicine Press
Epidemiology of nosocomial infections in medicine intensive care unit at a tertiary care hospital in northern India
Shabina Habibi MD *
Naveet Wig MD MPH *
Sunil Agarwal MD *
Surendra K Sharma MD PhD *
Rakesh Lodha MD 
Ravindra M Pandey MSc PhD *
Arti Kapil MD 
* Department of Medicine;
Department of Paediatrics;
Department of Microbiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
Correspondence to: Naveet Wig, Department of Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India Email: naveet_wig{at}yahoo.com
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SUMMARY
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This prospective observational study describes the rates of
nosocomial infections (NI), the sites of infection, the pathogens
involved, their antibiogram and the risk factors at a tertiary
care hospital in northern India. In 62 of the 182 enrolled patients
95 episodes of NI were recorded (incidence rate 28.6/1000 person
days): pneumonia (77%); urinary tract infection (24%) and blood
stream infection (24%). All isolates of Acinetobacter, Pseudomonas
and Klebsiella and 83.3%
of Escherichia coli were resistant
to the third generation cephalosporins. An increased duration
of the time spent in intensive care units and days of intervention
were associated with incident NI.
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Introduction
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Nosocomial infections (NIs) result in increased morbidity, mortality
and length of hospital stay.
1 The Incidence of NIs, their risk
factors and the antibiogram patterns vary across and within
countries.
2 Furthermore, intensive care units (ICUs) act as
epicentres for NI and the development of antimicrobial resistance
due to prolonged hospitalization, serious illness and a high
use of antibiotics.
3
There are very few published studies on the epidemiology of NIs from India. In this study, we report rates, infection sites, pathogens, risk factors and the antibiotic sensitivity of NI in ICU patients of at a tertiary care hospital in northern India.
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Methods
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This prospective observational study was done at an eight-bed
medical ICU of a tertiary care referral hospital in northern
India. An open cohort of all patients admitted to the unit from
January 2004 to July 2005 was followed for NIs, until either
discharge from the ICU or death. Patients who died or were transferred
from the ICU within 48 hours of their entry were excluded from
the study. Those who already had had an infection within <48
hours were followed for superadded infections. Active surveillance
was carried out to identify the NI according to the definitions
of the Center for Disease Control and Prevention (CDC).
4
Baseline cultures of blood, urine and tracheal aspirate (for intubated patients) were sent for the isolation of pathogens, and antimicrobial sensitivity testing, in accordance with Clinical and Laboratory Standard Institute Guidelines.5 Further samples were tested according to the suspected sites of infection, in patients with a clinical suspicion of infection. Pneumonia was defined based on the CDC definition.
The association between the clinical factors, interventions and NIs was tested using chi-squared test. The relationship between the duration of ICU stay and NIs was tested using a linear model with transformations. SAS version 9.1.3 (Cary, NC, USA) was used for analysis.
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Results
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One hundred and eighty-two (58.3%) of the 312 patients admitted
to ICU during study duration met the inclusion criteria. All
study participants/their proxies (for comatose patients) gave
informed consent.
The demographic and clinical characteristics of patient are as follows: men 64.3%, mean age 48.8 years, mean Acute Physiology and Chronic Health Evaluation (APACHE II score) 14 (range: 4–52). Hypotension and type II respiratory failure were the most common indications for ICU admission. Sixty-two patients (34.1%) had had one or more NI episodes (total 95 episodes). The incidence rate (IR) of NI was 28.6/1000 patient days at risk.
Common infection sites were: pneumonia (77.4%, 63 episodes, IR = 22.1/1000 patient days); urinary tract infection (UTI) (33.9%, 23 episodes, IR = 9.7/1000 patient days); and catheter-related blood stream infection (BSI) (19.4%, nine episodes, IR = 2.3/1000 patient days).
Ninety-eight percent of the intubated patients and 43.8% of patients with tracheostomy had pneumonia (IR = 31.4/1000 ventilator days). All patients with nosocomial UTI had a urinary catheter in situ (IR = 11.3/1000 urinary catheter-days). All patients with nosocomial BSIs had a central line and 80% had a peripheral intravenous line (IR = 3.4/1000 central venous pressure (CVP) line days).
Acinetobacter (58.3% episodes), Pseudomonas (43.7% episodes), E. coli (10.4% episodes) and Enterococci (1.2% episodes) were the most common pathogens isolated from patients with pneumonia. Similarly, Candida spp. (90.4% of the episodes), Pseudomonas (14.2% episodes) and E. coli (4.76% episodes) were isolated from nosocomial UTI. Organisms causing nosocomial BSIs were Pseudomonas (33.3% episodes), and Acinetobacter, E. coli, Candida spp., Coagulase-negative staphylococci and Staphylococcus aureus caused one episode each. These BSI organisms were isolated from cultures of blood and the CVP line tip.
The antibiogram of the pathogens to the commonly used antibiotics is shown in Table 1. Additionally, both coagulase-negative staphylococcus and Staphylococcus aureus were methicillin resistant but showed in vitro sensitivity to linezolid and vancomycin.
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Table 1 The antibiotic resistance pattern of common pathogens isolated in 62 bacterial isolates of patients admitted to the intensive care unit of a tertiary care hospital in northern India
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The analysis of the few risk factors is shown in Table
2.
Importantly, the length of stay in ICU was linearly associated
with NI (
P for trend <0.001). Notably, no patient staying
less than five days in ICU developed NI. Intubation and mechanical
ventilation (relative risk [RR] = 12.4 [1.6, 93.9]), tracheostomy
(RR = 5.59 [2.3, 13.2]) and nasogastric tube insertion (RR =
5.48 [1.7–42.8]), were associated with a risk of developing
nosocomial pneumonia. Similarly, urinary catheterization was
associated with nosocomial UTI (RR = 2.50 [1.02–6.1]).
Also, central venous catheterization (but not a peripheral venous
line) was associated with development of nosocomial BSI (RR
= 4.38 [2.2–8.7]).
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Table 2 Risk factors for the development of a nosocomial infection (NI) in an intensive care unit (ICU) in northern India (n = 182)
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The mean duration of at-risk ICU stay for those who developed
NI was 20.1 days (range 5–68 days) compared with eight
days for those who did not develop NI (range 3–28 days).
A total of 105/182 (57.6%) patients died during the follow-up
period. Of the 62 patients with NI, 32 (53.3%) died and 28.8%
of these deaths were attributed to the infection. Mortality
in patients without NI was 69.5% and was not statistically different
from those without NI (
P = 0.57).
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Discussion
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NIs are seen worldwide but are less studied and are given less
emphasis in developing countries. This study reports a high
IR of NI, as well as high antibiotic resistance, in ICU settings
of a tertiary care hospital in northern India. The relatively
high incidence of NI observed in this study may be a reflection
of the higher severity of illness, poorer nutritional status,
more interventions, fewer staff and, possibly, poor adherence
to aseptic measures. Also, the high proportion of mechanical
ventilation (84.1%) could partly account for higher IR of nosocomial
pneumonia. The ICU of low resource countries may have to cope
with patients with severe illness coupled with the lack of resources
and expertise needed to control NI.
Decreasing ICU stay duration and patient days on intervention are important for reducing the incidences of NI.6 Furthermore, the resistance pattern is alarming: four of the most common isolates are almost resistant to the third generation cephalosporins, i.e. ceftazidine and cefotaxime. The empirical treatment of choice in serious NI in ICUs would be cefoperazone-sulbactam. A study of antibiotic sensitivity patterns is vital for the effective management of NIs and the decision to use antibiotic cycling to reduce NIs.7
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Conclusion
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It is important to study NIs in developing countries in order
to adapt strategies to reduce the risk of NIs and antimicrobial
resistance.
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References
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- Weinstein RA. Nosocomial infection update. Emerg Infect Dis 1998;4:416–20[Medline]
- Emori TG, Culver DH, Horan TC, et al. National nosocomial infections surveillance system (NNIS): Description of surveillance methods. Am J Infect Control 1991;19:19–35[Medline]
- Kollef MH, Fraser VJ. Antibiotic resistance in the intensive care unit. Ann Intern Med 2001;134:298–314[Abstract/Free Full Text]
- Garner JS, Jarvis WR, Emori TG, Horan TC, Hughes JM. CDC definitions for nosocomial infections 1988. Am J Infect Control 1988;16:128–40[Medline]
- National Committee for Clinical Laboratory Standards. Performance Standards for Antimicrobial Susceptibility Testing: Twelfth Informational Supplement M100-S12. Wayne, PA: NCCLS, 2002
- Freeman J, McGowan JEJr. Risk factors for nosocomial infection. J Infect Dis 1978;138:811–9[Medline]
- Kollef MH. Time to get serious about infection prevention in the ICU. Chest 2006;130:1293–6[Medline]
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SUMMARY
Introduction
