Antimicrobial resistance in bacteria causing ventilator-associated pneumonia in a tertiary care hospital: one year prospective study

Neelima Ranjan, K. P. Ranjan, Uma Chaudhary, Dhruva Chaudhry

Abstract


Background: Ventilator-associated pneumonia (VAP) is the most common infection diagnosed in intensive care units (ICUs). The causative organisms of VAP vary among different populations and are increasingly associated with resistance against various antimicrobial agents. Objective of current study was to determine the bacteriological etiology of VAP, antimicrobial susceptibility pattern of the isolates and detect the presence of extended-spectrum b-lactamases (ESBL), metallo β-lactamases (MBL) and AmpC b-lactamases in multidrug resistant isolates causing VAP in the medical ICU.

Methods: A prospective study was carried out over a year to know the various etiological agents of VAP and their drug susceptibility patterns. ESBL, MBL and AmpC b-lactamases were detected in various isolates by combination disk method, imipenem-EDTA combined disk method and AmpC disk method respectively.

Results: The majority of bacterial isolates causing VAP were found to be gram negative bacilli. Acinetobacter spp accounted for 34.28% of VAP cases followed by Pseudomonas aeruginosa which was responsible for 25.71% cases. Other gram negative bacilli isolated were Klebsiella pneumoniae, Citrobacter freundii, Enterobacter spp, and Escherichia coli. Out of the total 70 isolates, 67 (95.7%) were multidrug resistant and not even a single isolate was sensitive to all the drugs tested.

Conclusions: Most of the pathogens causing VAP in our institute were multidrug resistant and in many isolates this resistance was due to production of ESBL, MBL, and AmpC β-latamases. Polymixin-B and colistin were found to be highly effective against multidrug resistant Acinetobacter spp and P. aeruginosa.

 


Keywords


Ventilator-associated pneumonia, Intensive care unit, ESBL, MBL, AmpC b-lactamases

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References


Morehead R, Pinto S. Ventilator-associated pneumonia: review article. Arch Intern Med. 2000;160:1926-36.

Guidelines for management of adults with hospital acquired, Ventilator associated and health care associated pneumonia. Am J Respir Crit Care Med. 2005;171:388-416.

Jean Chastre, Jean Yves Fagon. Ventilator associated pneumonia. Am J Respir Crit Care Med. 2002; 165: 867-903.

Joseph P. Lynch III. Hospital-Acquired Pneumonia: Risk Factors, Microbiology, and Treatment. Chest 2001;119:373S-84S.

Institute for Healthcare Improvement: Ventilator-associated pneumonia (VAP) Rate per 1,000 ventilator days, 2011. Available at: http://www.ihi.org/IHI/ Topics/CriticalCare/IntensiveCare/Measures/Ventilator Associated Pneumonia. Accessed 2 Feb 2011.

Ibrahim EH, Ward S, Sherman G, Schaiff R, Fraser VJ, Kollef M. Experience with a clinical guideline for the treatment of ventilator associated pneumonia. Crit Care Med 2001;29:1109-15.

Collee JG, Fraser AG, Marimion BP, Simmons A. Laboratory strategy in the diagnosis of infective syndromes. In: Collee JG, Fraser AG, Marimion BP, Simmons A, eds. Mackie and McCartney Practical Medical Microbiology: 14th ed. New York: Churchill Livingstone; 1996: 53-95.

Fagon JY, Chastre J et al. Invasive and non-invasive strategies for management of suspected ventilator associated pneumonia. Ann Intern Med. 2000;132:621-30.

Marquette CH, Georges H et al. Diagnostic efficacy of endotracheal aspirates with quantitative bacterial cultures in intubated patients with suspected pneumonia. Am Rev Respir Dis. 1993;148:138-44.

Collee JG, Miles RB, Watt B. Test for identification of bacteria. In: Collee JG, Fraser AG, Marimion BP, Simmons A, eds. Mackie and McCartney Practical Medical Microbiology: 14th ed. New York: Churchill Livingstone; 1996: 131-49.

Bauer AN, Kirby WMM, Sherris J et al. Antibiotic susceptibility testing by a standardized single disk method. Am J Clin Pathol. 1966;45:493-6.

Clinical and Laboratory Standards Institute. Performance standards for antimicrobial disk susceptibility testing. Approved standards, CLSI Document 20th ed. US: Wayne PA; 2010; 30(1): M2-A7.

Sinha P, Sharma R, Rishi S, Sharma R, Sood S, Pathak D. Prevalence of extended spectrum beta lactamase and AmpC beta lactamase producers among Escherichia coli isolates in a tertiary care hospital in Jaipur. Indian J Pathol Microbiol 2008;51:367-9.

Yong D, Lee K, Yum JH, Shin HB, Rossolini GM, Chong Y. Imipenem-EDTA disk method for differentiation of metallo-β-lactamases producing clinical isolates of Pseudomonas spp and Acinetobacter spp. J Clin Microbiol 2002;40:3798-801.

Panwar R, Vidya S Nagar, Alaka K Deshpande. Incidence, clinical outcome, and risk stratification of ventilator associated pneumonia- a prospective cohort study. I J Crit Care Med 2005;9(4):211-6.

C Mukhopadhyay, A Bhargava, A Ayyagari. Role of mechanical ventilation & development of multidrug resistant organisms in hospital acquired pneumonia. Indian J Med Res 2003 December;118:229-35.

Noyal Mariya Joseph, Sujatha Sistla, Tarun Kumar Dutta, Ashok Shankar Badhe, Desdemona Rasitha, Subhash Chandra Parija. Ventilator-associated pneumonia in a tertiary care hospital in India: role of multi-drug resistant pathogens. JIDC

April;4(04):218-25.

De AS, Kumar SH, Baveja SM. Prevalence of metallo-β-lactamase producing Pseudomonas aeruginosa and Acinetobacter species in intensive care areas in a tertiary care hospital. Indian J Crit Care Med 2010;14:217-9.

Dey A, Bairy I. Incidence of multidrug-resistant organisms causing ventilator-associated pneumonia in a tertiary care hospital: A nine months' prospective study. Ann Thorac Med 2007;2:52-7.

Seifert H, Baginski R, Schulze A, Pulverer G. Antimicrobial susceptibility of Acinetobacter species. Antimicrob Agents Chemother 1993;37(4):750-3.