Health care associated infections pose a major threat to patient safety contributing to significant morbidity, mortality and economic burden. The occurrence of these infections is associated with various factors among which an important one is the increasing use of invasive medical devices. These foreign devices which seem to be a blessing in disguise are responsible for device associated infections (DAIs). About 60-70% of nosocomial infections are associated with implanted medical devices (1). In this population of patients, 95% of cases of urinary tract infection are catheter related, 87% of cases of bloodstream infection are associated with indwelling vascular catheters, and 86% of cases of pneumonia are due to mechanical ventilation (2). The management of these infections is a big challenge as they may lead to persistent and resistant infections by providing a safe shelter to the microorganisms inside the biofilm formed on the device. These biofilms act as a nidus for chronic infections which are recalcitrant to antimicrobial therapy (3). A thick biofilm is formed within 24 hours on the entire surface of these plastic devices even with a small initial number of bacteria spreading at a rate of up to 0.5 cm per hour (4). The hazards associated with use of medical devices might far exceed those arising from device failures.
Though majority of studies on device-associated infections are from developed countries, the problem may even be grave in developing countries. The rates of DAIs have been assessed in a multicenter prospective cohort surveillance study of 46 hospitals in Central and South America, India, Morocco, and Turkey, between 2002 and 2005 (5). An overall rate of 14.7 percent or 22.5 infections per 1000 ICU days, was observed.
Indian Council of Medical Research, Department of Health Research has issued the ICMR Antimicrobial Guidelines for Device Associated Infections. Following are the major recommendations :
Case definitions :
Healthcare-associated infections : A localized or systemic condition resulting from an adverse reaction to the presence of an infectious agent(s) or its toxin(s) that occurs in a patient in a healthcare setting (e.g., a hospital or outpatient clinic), and was not found to be present or incubating at the time of admission unless the infection was related to a previous admission to the same setting (1).
Device associated infection (DAI) : An infection in a patient with a device (e.g., ventilator or central line) that was used within the 48-hour period before onset of infection. If the interval is longer than 48 hours, there must be compelling evidence that the infection was associated with device use. There is no minimum period of time that these devices must be in place for the infections to be considered device-associated (6).
Central line associated blood stream infection (CLABSI) : CLABSI is defined when a patient with a central line in place (or in the 48 hours after line removal) has a recognized pathogen cultured from one or more blood cultures that is not related to an infection at another site, or has at least one of the following signs or symptoms: fever >38°C, chills, hypotension, and a common skin contaminant is cultured from two or more blood cultures drawn on separate occasions, when signs, symptoms, and positive laboratory results are not related to an infection at another site (7).
Catheter related bloodstream infections (CRBSI) are defined on the basis of following criteria :
- A positive semi quantitative (>15 colony-forming units [CFU]/catheter segment) or quantitative (>103 CFU/catheter segment) cultures whereby the same organism (species and similar antibiogram) is isolated from the catheter segment and peripheral blood
- Simultaneous quantitative blood cultures with a ≥5:1 ratio CVC versus peripheral
- For automated systems a differential period of CVC culture versus peripheral blood culture positivity where CVC culture flags positive before peripheral blood culture by >2 hours
Table 1 Common pathogens associated with DAIs:
|Gram-positive cocci||Gram-negative bacilli||Fungi|
|Staphylococcus aureus||Escherichia coli and Klebsiella species||Candida species|
|Coagulase negative Staphylococcus||Pseudomonas aeruginosa||Aspergillus species|
|Enterococcus faecalis/E. faecium||Enterobacter species||Malassezia furfur|
Uncommon pathogens are: Mycobacterium spp., Flavobacterium spp., Corynebacterium spp. and Ochrobacterum anthropi (8).
Ventilator-associated pneumonia (VAP) is a common complication of ventilatory support for patients with acute respiratory failure. Ventilator-associated pneumonia (VAP) is common in the intensive care unit (ICU), affecting 8 to 20% of ICU patients and up to 27% of mechanically ventilated patients. Common pathogens include Pseudomonas species and other highly resistant Gramnegative bacilli, the Enterobacteriaceae, staphylococci, streptococci, and Haemophilus species. Atypical bacteria, viruses, and fungi also have been implicated as causes of VAP, but their role is presently unclear (9).
Diagnosis and treatment : Several criteria have been proposed for diagnosing VAP in clinical settings, including clinical manifestations, imaging techniques, methods to obtain and interpret bronchoalveolar specimens, and biomarkers of host response. But the accuracy of these methods in diagnosing VAP is controversial because of non-availability of a gold standard. Quantitative cultures of bronchoalveolar lavage (BAL) seem to be fairly equivalent in diagnosing VAP, while blood cultures are relatively insensitive. If VAP is suspected, obtain lower respiratory tract samples for quantitative and semiquantitative cultures and microscopy. Begin empirical antimicrobial therapy, unless there is very low suspicion of pneumonia and microscopy of LRT sample is negative. Assess the clinical improvement at 48-72 hours. If patient shows improvement, and culture is negative, stop the antibiotics and if culture is positive reassess the patient after giving antibiotics for 7-8 days. If there is no clinical improvement, search for other pathogens or complications (10).
CRBSI and CLABSI
Intravascular devices are commonly used these days to administer IV fluids, medications, blood products, parenteral nutrition, and to monitor the hemodynamic status of critically ill patients. These patients usually have a compromised immune system making them predisposed to DAIs. Accurate diagnosis is essential in the management of these infections.
Diagnostic investigations for CRBSI:
The diagnosis of CRBSI is very challenging. The clinical diagnosis is not a reliable method as the fever and chills associated with CRBSI are not specific and local catheter site inflammation has a sensitivity of ≤ 3%. Therefore, it is important to follow microbiological techniques to establish the catheter as the source of blood stream infections. These techniques include (11):
A. Catheter sparing diagnostic methods
- Qualitative blood culture through the device
- Quantitative blood cultures through the device
- Simultaneous quantitative blood cultures
- Differential time to positivity with automated culture systems
- Acridine orange leukocyte spin
- Endoluminal brush
B. Diagnostic methods requiring catheter removal
- Semi-quantitative roll plate catheter culture
- Quantitative catheter segment culture
- Microscopy of stained catheters
Quantitative blood cultures through the device : The blood sample drawn only through the CVC is cultured by lysis centrifugation method and the colony count of >100 CFU/ml helps in diagnosing CRBSI. But, this method cannot distinguish CRBSI from high grade bacteremia especially in immunocompromised patients with high grade sepsis. Sensitivity of this method is 77% and specificity is 90%.
Simultaneous quantitative blood culture : Paired blood samples are obtained simultaneously from CVC and peripheral vein. If both the cultures show growth of similar organism with a colony count that is five-fold or greater from blood culture drawn through the CVC versus peripheral vein is indicative of CRBSI. The pooled sensitivity and specificity for short-term catheters 75% and 97%, respectively, and for long-term catheters 93% and 100%, respectively.
Differential time to positivity : It is a simple technique and involves simultaneous qualitative blood cultures drawn through the catheter and a peripheral vein. Definite diagnosis of CRBSI is established when the blood culture drawn from the CVC becomes positive at least 2 hours earlier than the blood culture drawn from the peripheral vein. A meta-analysis found the pooled sensitivity and specificity for this method of diagnosing CRBSI in short-term catheters to be 89% and 87%, respectively, compared with 90% and 72%, respectively, for long-term catheters. Automated blood culture systems used for this excludes any extra cost or labour for this method.
Acridine orange leukocyte cytospin : Acridine orange leukocyte cytospin (AOLC) is a rapid diagnostic microscopy method. In this 1 ml blood sample is drawn through CVC, centrifuged and stained with acridine orange. Under fluorescence microscope, if any bacteria are seen, it is considered to be positive. This method has a sensitivity of 87% and specificity of 94%. This is a recent method and currently under investigation.
Endoluminal brush technique : This is not a widely used method because of the various side effects associated with it. In this, a tapered nylon brush on a steel wire is passed through the catheter hub and lumen, withdrawn and placed in a buffered container. This solution is cultured onto blood agar plates after sonication and vortexing. Colony counts >100 CFU/ml are considered positive for CRBSI. Kite and colleagues reported sensitivity for this test of 95% and a specificity of 84%.
Semiquantitative roll plate culture technique : In this method, the distal segment of the CVC is cut and rolled against a blood agar plate at least four times and then the plate is incubated overnight. After incubation a colony count of ≥15 CFU/ ml suggests that the catheter is colonized with the organism grown. But the same organism must grow from the peripheral blood culture to label it as CRBSI. The pooled sensitivity and specificity for roll-plate catheter culture in was calculated to be 84% and 85%, respectively (9).
Quantitative catheter segment culture : Several methods such as centrifugation, vortexing, and sonication have been used to retrieve organisms from both the external and internal surfaces of the catheter. A 5 cm catheter segment is removed, flushed or sonicated with the broth, serially diluted and plated on blood agar. The plates are incubated at 35°C and a count of ≥100 CFU per catheter segment is deemed positive. The pooled sensitivity and specificity of quantitative catheter segment culture for short-term catheters were 82% and 89%, respectively, and 83% and 97% for long-term catheters, respectively (9).
Microscopy of stained catheters : Gram staining and acridine orange staining are also used for diagnosis of CRBSI. Gram staining has been reported to show 100% sensitivity and 97% specificity while acridine orange has a sensitivity of 84% and specificity of 99%.
A recent meta-analysis found that paired quantitative blood culture is the most accurate method for the diagnosis of CRBSI, followed by quantitative blood culture through the catheter and quantitative or semiquantitative catheter segment cultures(12).
Relevant IDSA guidelines (8) for diagnosis of CRBSI include:
Catheter culture :
- For central venous catheters (CVCs), the catheter tip should be cultured, rather than the subcutaneous segment.
- For cultures of an anti-infective catheter tip, use specific inhibitors in the culture media.
- When catheter infection is suspected and there is a catheter exit site exudate, swab the drainage to collect specimens for culture and Gram staining.
Blood Culture :
- The blood samples should be obtained prior to the initiation of antibiotic therapy, taking aseptic precautions.
- For suspected CRBSI, paired blood samples, drawn from the catheter and a peripheral vein, should be cultured before initiation of antimicrobial therapy, and the bottles should be appropriately marked to reflect the site from which the samples were obtained.
- If a blood sample cannot be drawn from a peripheral vein, it is recommended that ≥2 blood samples should be drawn through different catheter lumens. It is unclear whether blood cultures should be drawn through all catheter lumens in such circumstances.
- A definitive diagnosis of CRBSI requires that the same organism grow from at least 1 percutaneous blood culture and from a culture of the catheter tip, or that 2 blood samples be drawn (one from a catheter hub and the other from a peripheral vein) that, when cultured, meet CRBSI criteria for quantitative blood cultures or differential time to positivity (DTP).
- Alternatively, 2 quantitative blood cultures of samples obtained through 2 catheter lumens in which the colony count for the blood sample drawn through one lumen is at least 3-fold greater than the colony count for the blood sample obtained from the second lumen should be considered to indicate possible CRBSI. In this circumstance, the interpretation of blood cultures that meet the DTP criteria is an unresolved issue.
- For quantitative blood cultures, a colony count of microbes grown from blood obtained through the catheter hub that is at least 3-fold greater than the colony count from blood obtained from a peripheral vein best defines CRBSI.
- Before starting antimicrobial therapy, it is recommended to do quantitative blood cultures and/or DTP.
Prevalent antimicrobial resistance status among common pathogens :
According to the International Nosocomial Infection Control Consortium (INICC), the overall resistance pattern of the common pathogens was found as follows (13) :
- 87.5% of all Staphylococcus aureus HCAIs were caused by methicillinresistant strains,
- 71.4% of Enterobacteriaceae were resistant to ceftriaxone and 26.1% to piperacillin–tazobactam;
- 28.6% of the Pseudomonas aeruginosa strains were resistant to ciprofloxacin, 64.9% to ceftazidime and 42.0% to imipenem.
Table 2: The following table shows ICMR surveillance network reports in 2014:
|Resistant Pathogen||Resistance (%) in 2014|
|Vancomycin Resistant Enterococci (VRE)||8.6 %|
|Methicillin resistan Staphylococcus aureus (MRSA)||35.7 %|
|P. aeruginosa resistant to imipenem||37 %|
|A. baumannii resistant to carbapenems||63 %|
|Enterobacteriaceae resistant to third generation cephalosporins, mainly extendedspectrum beta-lactamase producers||83 % (K. pneumoniae)
80 % (Escherichia coli)
|Enterobacteriaceae resistant to carbapenems (CREs)
|35 % (K. pneumoniae)
18 % (Escherichia coli)
This increasing trend of resistance points towards a dire need to strictly follow the infection control practices.
Treatment of CRBSI (14) :
The three important considerations in the management of CRBSIs include :
- Removal of the indwelling device or catheter
- Salvage of the device
- Antimicrobial chemotherapy (type and duration of therapy)
- Removal or salvage of the catheter depends upon various factors:
- The type of catheter used (tunnelled or non-tunnelled) In most cases of non-tunnelled CVC–related bacteremia and fungemia, the CVC should be removed.For management of blood stream infections from a tunneled catheter or implantable device, such as a port, the decision to remove the catheter or device should be based on the severity of the patient’s illness, documentation that the vascular-access device is infected, assessment of the specific pathogen involved, and presence of complications, such as endocarditis, septic thrombosis, tunnel infection, etc
- The organism isolated in blood culture : Catheter removal is recommended in all infections caused by S. aureus, gram negative bacilli, Enterococcus spp. and Candida spp. The catheter may be retained with CoNS, if systemic antimicrobial therapy is given along with antibiotic lock therapy.
- Hemodynamic or immune status of the patient : The importance of catheter for the survival of the patient also helps in deciding that whether the catheter can be removed or not.
- Long-term catheters should be removed from patients with CRBSI associated with any of the following conditions: severe sepsis; suppurative thrombophlebitis; endocarditis; bloodstream infection that continues despite >72 h of antimicrobial therapy to which the infecting microbes are susceptible; or infections due to S. aureus, P. aeruginosa, fungi, or mycobacteria.
- Short-term catheters should be removed from patients with CRBSI due to gram-negative bacilli, S. aureus, enterococci, fungi, and mycobacteria.For long-term and short-term CRBSI due to less virulent microbes that are difficult to eradicate (e.g., Bacillus species, Micrococcus species, or propionibacteria), catheters should generally be removed after blood culture contamination is ruled out on the basis of multiple positive culture results, with at least 1 blood culture sample drawn from a peripheral vein.
Catheter salvage : Removal of device is not always the preferred option, sometimes salvage of catheter is the preferred option. In uncomplicated CRBSI involving long-term catheters due to pathogens other than S. aureus, P. aeruginosa, Bacillus species, Micrococcus species, propionibacteria, fungi, or mycobacteria, patients undergoing hemodialysis or other patients who require long term intravascular access for survival, catheter should be retained in place with use of antimicrobial lock therapy.
- For patients with CRBSI for whom catheter salvage is attempted, additional blood cultures should be obtained, and the catheter should be removed if blood culture results (e.g., two sets of blood cultures obtained on a given day; one set of blood cultures is acceptable for neonates) remain positive with blood
- If a catheterized patient has a single positive blood culture that grows coagulase-negative Staphylococcus species, additional cultures of blood samples obtained through the suspected catheter and from a peripheral vein should be performed before the initiation of antimicrobial therapy and/or catheter removal (8).
- Urokinase and other thrombolytic agents are not recommended as adjunctive therapy for patients with CRBSI(8).
- Empirical antimicrobial therapy (8) : After appropriate cultures of blood and catheter samples are done, empirical i/v antimicrobial therapy should be initiated. This therapy is based on the severity of illness and the potential pathogens involved.
- Vancomycin is usually recommended as the empirical antimicrobial therapy in areas with an increased incidence of methicillin-resistant staphylococci.
- Linezolid is not recommended as empirical therapy in patients suspected to have CRBSI.
- Daptomycin acts as an alternative for institutions where MRSA isolates have vancomycin minimum inhibitory concentration (MIC) values of >2 µg/mL.
- In the absence of methicillin-resistant S. aureus, penicillinaseresistant penicillins, such as nafcillin or oxacillin, or a first generation cephalosporin like cefazolin should be used.
- Empirical coverage for gram-negative bacilli should be based on local antimicrobial susceptibility data and the severity of disease (e.g., a fourth-generation cephalosporin, carbapenem, or β- lactam/β-lactamase combination, with or without an aminoglycoside).
- Empirical combination antibiotic coverage for multidrug-resistant (MDR) gram-negative bacilli, such as Pseudomonas aeruginosa, should be used when CRBSI is suspected in neutropenic patients, severely ill patients with sepsis, or patients known to be colonized with such pathogens, until the culture and susceptibility data are available and de-escalation of the antibiotic regimen can be implemented.
- In cases of suspected CRBSI involving femoral catheters a broad coverage for gram-positive pathogens, gram-negative bacilli, as well as for Candida species is recommended.
- Empirical therapy for suspected catheter-related candidemia should be used for septic patients with any of the following risk factors: total parenteral nutrition, prolonged use of broadspectrum antibiotics, hematologic malignancy, bone marrow or solid-organ transplant, femoral catheterization, or colonization due to Candida species at multiple sites.
- For empirical treatment of suspected catheter-related candidemia, use an echinocandin or, in selected patients, fluconazole. Fluconazole can be used for patients without azole exposure in the previous 3 months and in health care settings where the risk of Candida krusei or Candida glabrata infection is very low.
- Use of amphotericin B or, for selected patients, iv fluconazole should also be considered for empirical treatment when fungemia is suspected. Initial antimicrobial therapy should be given intravenously, but once the patient is clinically stable and antibiotic susceptibilities are known, an oral quinolone, such as ciprofloxacin, trimethoprim-sulfamethoxazole, or linezolid, could be administered.
When a catheter-related infection is documented and a specific pathogen is identified, systemic antimicrobial therapy should be narrowed and consideration given for antibiotic lock therapy, if the CVC or implantable device is not removed.
Table 3 Pathogen-specific antimicrobial therapy according to the pathogen isolated (8).
|Pathogen||Preferred therapy with dosage||Alternative therapy|
|MSSA (Methicillin Sensitive Staphylococcus aureus)||Oxacillin, 2 g q4h
|Cefazolin, 2 g q8h; or vancomycin, 15 mg/kg q12h. For patients receiving hemodialysis, administer: Cefazolin, 20 mg/kg (actual weight), round to nearest 500-mg increment, after dialysis.|
|MRSA(Methicillin Resistant Staphylococcus aureus)||Vancomycin, 15 mg/kg q12h||Daptomycin, 6–8 mg/kg per day, or linezolid; or vancomycin plus rifampin (or gentamicin); or TMP-SMZ alone (if susceptible).|
|MS-CoNS (Methicillin Sensitive Coagulase negative staphylococci)||Oxacillin, 2 g q4h
|First-generation cephalosporin or vancomycin or TMP-SMZ (if susceptible). MR-CoNS (Methicillin Resistant Coagulase negative staphylococci) Vancomycin, 15 mg/kg iv q12h Daptomycin 6|
|Enterococcus faecalis/E. faecium: Ampicillin susceptible:
Ampicillin resistant vancomycin susceptible
|Ampicillin, 2 g q4h or q6h; or Ampicillin+/- Gentamicin, 1 mg/kg q8h;
Vancomycin, 15 mg/kg iv q12h+/-gentamicin, 1 mg/kg q8h
Linezolid, 600 mg q12h; or daptomycin 6 mg/kg per day
Linezolid or daptomycin 6 mg/kg per day
Quinupristin-dalfopristin 7.5 mg/kg q8h
|E. coli/ Klebsiella spp.: Extended spectrum beta
lactamase (ESBL) negative:
|Ceftriaxone, 1–2 g per day Cefoperozone
Sulbactam 2g q8h Ertapenem, 1 g per day; imipenem, 500 mg q6h; meropenem, 1 g q8h; or doripenem, 500 mg q8h;
|Enterobacter spp. and Serratia marcescens||Ertapenem, 1 g per day; imipenem, 500 mg q6h; meropenem, 1 g q8h;||Cefepime or ciprofloxacin|
|Cefepime, 2 g q8h; or imipenem, 500 mg q6h; or meropenem, 1 g q8h; or piperacillintazobactam, 4.5 g q6h, amikacin, 15 mg/kg q24h or tobramycin 5–7 mg/kg q24h|
|Acinetobacter spp.||Ampicillin/sulbactam, 3 g q6h; or imipenem, 500 mg q6h; meropenem, 1 g q8h|
|Stenotrophomonas maltophilia||TMP of 3–5 mg/kg q8h and 15 to 25 mg of SMX q8h||Ticarcilllin and clavulanic acid|
|Candida albicans or Candida spp.
|Caspofungin, 70-mg loading dose, then 50 mg per day; micafungin, 100 mg per day; anidulafungin, 200 mg loading dose followed by 100 mg per day; or fluconazole, 400–600 mg per day (6-12 mg/kg/day)||Lipid AmpB preparations
|Corynebacterium spp.||Vancomycin, 15 mg/kg q12h; alternative: linezolid (based on in vitro activity)|
|Burkholderia cepacia||TMP-SMZ, 3–5 mg/kg q8h; or imipenem, 500 mg q6h; or meropenem, 1 g q8h|
|Chryseobacterium spp. or Flavobacterium spp.||Levofloxacin750 mg q24h; alternative: TMPSMZ or imipenem or meropenem|
|Ochrobactrum anthropi||TMP-SMZ, 3–5 mg/kg q8h; or ciprofloxacin, 400 mg q12h; alternative: imipenem, meropenem, ertapenem, or doripenem plus aminoglycoside|
|Malassezia furfur||Amphotericin B||Voriconazole|
|Mycobacterium spp.||Susceptibility varies by species|
Duration of antimicrobial therapy in individual pathogens (11):
When denoting duration of antimicrobial therapy, day 1 is the first day on which negative blood culture results are obtained (8).
Vancomycin is the drug of choice for empirical treatment of CoNS related CRBSI and change to semisynthetic penicillin if the isolate is susceptible. The duration of therapy is 5-7 days if the catheter is removed, while the duration is 10-14 days along with antibiotic lock therapy, if the catheter is retained. Dalbavancin and daptomycin are alternative treatment options. Minocycline and EDTA, ethanol, or triple combination of minocycline and EDTA in 25% ethanol, constitutes alternative lock therapy (9).
S. aureus is frequently associated with septic thrombosis and endocarditis. Trans-esophageal echocardiography (15) should be done to identify patients with complicated bacteremia and requiring 4-6 weeks of treatment. In cases of negative TEE, duration of therapy is two weeks. Catheter removal is usually recommended and is associated with a rapid response and a lower relapse rate. The antibiotics recommended for S aureus bacteremia are the β-lactam antibiotics (antistaphylococcal penicillin or cefazolin, if allergic to penicillin). For patients with serious allergy to β-lactams and for those with methicillin-resistant S. aureus, vancomycin is the drug of choice.
Gram-negative bacilli and miscellaneous pathogens
Catheter removal and appropriate antimicrobial therapy for 10-14 days is recommended for patients with catheter-related, gram-negative bacteremia with non-tunnelled CVCs. Catheter salvage can be done in suspected CRBSI in hemodynamically unstable patients with tunneled CVCs and can be treated for 14 days with systemic and antibiotic lock therapy. The preferred antibiotics include quinolones, such as ciprofloxacin with or without rifampin. This treatment duration is increased to 4-6 weeks if bacteremia is prolonged even after appropriate antimicrobial therapy and catheter removal, especially in the presence of underlying valvular heart disease.
Antibiotic lock therapy : Intraluminal colonization is the major mechanism for the occurrence of CRBSIs in patients with long-term devices. Parenteral antimicrobials or antiseptics (e.g., ethanol) with or without anticoagulants are infused into the catheter hub and allowed to dwell at supratherapeutic concentrations. Antibiotic lock solutions are not recommended to be used routinely to prevent CRBSI. These are indicated in patients with long-term cuffed or tunneled catheter, or port with a history of multiple infections and in CRBSI patients in whom catheter salvage is recommended (16). The antimicrobial concentration used in lock solution is 100-1000 times the minimum inhibitory concentration (MIC) to kill the bacteria within the biofilm. The risks of using antimicrobial lock therapy include potential toxicity and the potential to develop resistance. Various solutions used are; heparin (10 IU/ml), heparin-vancomycin (25μg/ml) and heparin-vancomycin-ciprofloxacin (2 μg/ml). A combination of minocycline hydrochloride and EDTA was found to be synergistic against resistant Gram-positive and Gram-negative bacteria and C. albicans. Other such solutions include: gentamicin and citrate, cefotaxime and heparin, taurolidine and citrate, and heparin (17).
Alternative treatment options : With the emergence of antimicrobial resistance, the enzymes like lysostaphin have been found to show good antistaphylococcal activity. Also ultrasound waves with a frequency of >20 KHz have been used to disrupt organisms from the surface of medical devices, especially if applied as high intensity ultrasound (>10W/cm2)(14).
Conclusion : The medical devices are an indispensable part of our health-care system. A large number of patients have to be managed with indwelling medical devices. In such unavoidable situations, recommended guidelines must be followed for proper use and maintenance of these devices and removal when no longer indicated.
Guidelines by Indian Council of Medical Research :
Dr Soumya Swaminathan, Director General, Indian Council of Medical Research Secretary, Department of Health Research