|Year : 2012 | Volume
| Issue : 2 | Page : 86-89
Device associated nosocomial infections and patterns of antimicrobial resistance at a tertiary care hospital
Banda Venkata Ramana, Abhijit Chaudhury
Department of Microbiology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
|Date of Web Publication||11-Jul-2012|
Banda Venkata Ramana
Assistant Professor, Department of Microbiology, Sri Venkateswara Institute of Medical Sciences, Tirupati - 517507, Andhra Pradesh
Aim : This prospective study was carried out over a period of 1 year in a tertiary care teaching hospital. The aim of the study was to determine the organisms causing device-related nosocomial infections and to study their anti-microbial resistance pattern.
Materials and Methods : Patients with endotracheal intubation, and central venous catheters (CVC)/venous cut down catheters were included in the study. Colonization of the endotracheal tube and colonization of the CVC/venous cut down catheters was studied.
Results: The most common organisms isolated from endotracheal tube tips were Pseudomonas aeruginosa (35%), Klebsiella pneumoniae (18%), Escherichia coli (15%), other enterobacteriaceae (19%), non-fermenting gram-negative bacilli (NFGNB) (13%), and methicillin-resistant Staphylococcus aureus (MRSA) (40%). Pseudomonas aeruginosa was the commonest organism, which showed highest frequency of resistance to gentamicin (81%) and ceftazidime (76%). The common organisms isolated from the vascular catheter tips were pseudomonas (30%), Klebsiella pneumoniae (18%), Escherichia coli (16%), other enterobacteriaceae (25%), NFGNB (11%), and MRSA (65%). Similar to ET tubes, here also pseudomonas aeruginosa was the commonest organism with maximum frequency of resistance to ceftazidime (69%).
Conclusion: Knowledge of the resident microbial flora and their anti-microbial susceptibility pattern is necessary for formulating a rational antibiotic policy in a hospital.
Keywords: Central venous catheter, device-associated infections, nosocomial infections
|How to cite this article:|
Ramana BV, Chaudhury A. Device associated nosocomial infections and patterns of antimicrobial resistance at a tertiary care hospital. J Dr NTR Univ Health Sci 2012;1:86-9
|How to cite this URL:|
Ramana BV, Chaudhury A. Device associated nosocomial infections and patterns of antimicrobial resistance at a tertiary care hospital. J Dr NTR Univ Health Sci [serial online] 2012 [cited 2013 May 22];1:86-9. Available from: http://www.jdrntruhs.org/text.asp?2012/1/2/86/98341
| Introduction|| |
Nosocomial infections are an important public health problem in many developing countries, particularly in intensive care units (ICUs).  Nosocomial infections are frequently encountered in ICUs because of the severity of underlying diseases, the frequency of invasive interventions, and the frequent use of wide-spectrum antibiotics. It has been reported that ICUs account for 25% of nosocomial infections, even though they occupy only approximately 10% of bed capacity of the hospital. The incidence of nosocomial infections in ICUs is showing a rising trend, mainly because of increasing invasive procedures performed in the ICUs. A likely explanation for this increased risk is that critically ill patients frequently require invasive medical devices such as urinary catheters, central venous and arterial catheters and endotracheal tubes, thus compromising normal skin and mucosal barriers.  Surveillance of nosocomial infections; particularly device-associated infections (DAI) helps in determining infection rates, risk factors and in further planning the preventive strategies to ensure a quality health care in any hospital. Data on surveillance of nosocomial infections in relation to device is available from national nosocomial infection surveillance System (NNIS), which is an international data pooled from different hospitals. Such data cannot be generalized, as each hospital has its own factors that can influence the rates of nosocomial infections.  In the present study, we aimed to determine the device-associated nosocomial infection rate, as well as to identify the infectious agents isolated and their resistance rate against certain antibiotics in our hospital from January 2010 to December 2010.
| Materials and Methods|| |
This prospective study was conducted in a tertiary care teaching hospital over a period of 1 year. All patients with endotracheal tubes (with or without mechanical ventilation), and central venous catheters/venous cut-down catheters were included in the study. The common indications for insertion of the endotracheal tube were for maintenance of airway patency and for mechanical ventilation. The endotracheal tube was inserted and removed using strict aseptic technique. After extubation, the tip of the endotracheal tube was cut with a sterile blade and sent in a sterile tube for bacterial culture. The culture was done on sheep blood agar and MacConkey's agar. The culture plates were incubated overnight and examined for growth. Organisms were identified on the basis of colony characteristics and biochemical reactions. The indications for central venous catheterization/venous cut-down catheterization were- for intravenous access and/or for central venous pressure monitoring. The catheter insertion was performed under strict aseptic precautions. A short section (approximately 5 cm) of the catheter (including the area directly beneath the skin) was aseptically cut off and sent to the laboratory in a sterile tube for culture. This section of the catheter was rolled across the surface of an agar plate with sterile forceps. After overnight incubation, the colonies were counted. A positive culture was defined as more than/equal to 15CFU.  The antibiotic susceptibility of the organisms (isolated from different sites) to various antibiotics was determined using the Kirby-Bauer method (Disk diffusion technique), and the results were interpreted as per clinical laboratory standards institute (CLSI) guidelines. 
| Results|| |
In our study, 642 patients had undergone central venous/venous cut-down catheterization and endotracheal tube intubation. Among these, 266 (41%) developed nosocomial infection. The most frequently isolated microorganisms from catheter infections were Pseudomonas aeruginosa (33.3%), Klebsiella pneumoniae (18%), Escherichia More Details coli (16%), other enterobacteriaceae (21.2%), non-fermenting gram negative bacilli (NFGNB) (12.1%), and methicillin resistant Staphylococcus aureus (MRSA) (57%) [Table 1].
Among 455 patients who underwent endotracheal intubation, colonization with bacteria was seen in 171 patients (37%). The organisms commonly isolated from endotracheal tube tips were Pseudomonas aeruginosa (35%), other enterobacteriaceae (19%), Klebsiella pneumoniae (18%), Escherichia coli (15%), NFGNB (13%), and MRSA (40%). The various organisms colonizing the endotracheal tube and their antibiotic resistance pattern are presented in [Table 2]. Pseudomonas aeruginosa was the commonest organism with maximum resistance to gentamicin (81%) and ceftazidime (76%).
|Table 2: Gram-negative organisms isolated from endotracheal tube tip cultures and their antibiotic resistant pattern (%)|
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187 patients had CVC/venous cut down catheter insertion. 95 catheter tips were positive for bacterial colonization out of 187 catheter tips (50.8%). The common organisms isolated from the catheter tips were Pseudomonas aeruginosa (30%), other enterobacteriaceae (25%), Klebsiella pneumoniae (18%), Escherichia coli (16%), NFGNB (11%), and MRSA (65%). The various organisms colonizing the endotracheal tube and their antibiotic resistance pattern are presented in [Table 3]. Pseudomonas aeruginosa was the commonest organism with maximum resistance to ceftazidime (69%). The commonest organisms isolated from various sites i.e. endotracheal tube tip, CVC/venous cut-down catheter tip together with their antibiotic resistance pattern are presented in [Table 4].
|Table 3: Organisms isolated from vascular catheter tip cultures and their antibiotic resistant pattern (%)|
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|Table 4: Common organisms isolated from various sites i.e. Endotracheal tube tip, cvc/Venous cut-down catheter tip together with their antibiotic resistance percentages|
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| Discussion|| |
Nosocomial infections are becoming an increasing problem for hospitalized patients, especially in the ICU, particularly those acquired following insertion of devices, are serious cause of concern for hospitals.  Pseudomonas aeruginosa was the commonest organism infecting endotracheal tube in our study, followed by Klebsiella pneumoniae and Escherichia coli. Most of the previous studies had isolated Pseudomonas aeruginosa as the commonest organism. ,,,
Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and MRSA to be commonest organisms colonizing the CVC/venous cut-down catheters in our study. Bentley et al., Darbyshire et al., Dillon et al., and Moran et al. have isolated Staphylococcus as the commonest organism colonizing the CVC. ,,, Moran et al. have also isolated Enterococcus, Proteus, and Pseudomonas.  Pseudomonas aeruginosa was the commonest organism from endotracheal tube tips with maximum resistance to gentamycin (81%) and ceftazidime (76%). The commonest organism isolated from CVC/venous cut down catheter was Pseudomonas aeruginosa with maximum resistance to ceftazidime (69%).
| Conclusions|| |
Gram-negative bacteria are common causes of device-associated nosocomial infections. Prevention is more important than management of device-associated infections, simple measures of asepsis while insertion of catheters and general management of hygiene can decrease the incidence of nosocomial infections. We recommended that education and awareness among health care workers as well as adherence to standard guidelines for prevention of nosocomial infections.
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[Table 1], [Table 2], [Table 3], [Table 4]