European Journal of Biotechnology and Bioscience  ~ 33 ~  Volume: 3, Issue: 5, 33-36 May 2015 www.biosciencejournals.com ISSN: 2321-9122 Impact Factor: 3.742 Kanaan Mansoor MD, Causality Medical Officer, Department of Emergency Medicine, Dr Ziauddin Medical University Hospital, Karachi, Sindh, Pakistan -75600. Syed Bilal Tanvir House Officer, Department of Surgery, Dr Ziauddin Medical University Hospital, Karachi, Sindh, Pakistan- 75600 Ali Shariq Assistant Professor Microbiology Department, Dr Ziauddin Medical University Hospital, Karachi, Sindh, Pakistan -75600 Arif Hussain Professor, Director Clinical Laboratories, Dr Ziauddin University Hospital, Karachi, Sindh, Pakistan -75600 Badar Jahan Farooqi Professor, Head of Department, Medical Microbiology, Dr Ziauddin University Hospital, Karachi, Sindh, Pakistan -75600 Sumera Ahmed Senior resident Gastroenterology Department, Dr Ziauddin Medical University Hospital, Karachi, Sindh, Pakistan-75600 Roofia Tanvir 3 rd year M.B,B.S Student, Ziauddin Medical University, Karachi, Sindh, Pakistan-75600 Correspondence: Kanaan Mansoor MD, Causality Medical Officer, Department of Emergency Medicine, Dr Ziauddin Medical University Hospital, Karachi, Sindh, Pakistan -75600. Frequency and susceptibility pattern of Multidrug Resistant Pseudomonas aeruginosa in isolates of patients from a tertiary care hospital of Karachi, Pakistan Kanaan Mansoor, Syed Bilal Tanvir, Ali Shariq, Arif Hussain, Badar Jahan Farooqi, Sumera Ahmed, Roofia Tanvir Abstract Objective: To determine the frequency and susceptibility pattern of multidrug resistant P.aeruginosa isolates from clinical specimens in a tertiary care hospital in Karachi, Pakistan. Methods: A cross sectional study was performed over a time frame of 2 years, from January 2013 to January 2015 at a tertiary care private hospital in Karachi. These specimens were collected from three different tertiary care units situated at three different locations of the city. Standard and specific microbiological methods were used to identify the clinical isolates. The isolates were cultured on chocolate and MacConkey agar. The susceptibility patterns were deduced by utilizing the Kirby Bauer Disc diffusion method on Mueller-Hinton Agar. Results: A total of 634 isolates of P. aeruginosa were cultured during this study’s time frame ranging from January 2013 to January 2015. Positive cultures were then tested against 9 antibiotics from the following classes of drugs: B-Lactams, Carbapenems, Aminoglycosides and Fluoroquinolones. 36.5% of the samples that were found to be resistant to 3 or more antibiotics, were labeled as MDR P. aeruginosa. The most sensitive drug was Colistin (100%), followed by Ciprofloxacin (66.8%), Piperacillin/Tazonbactam (49.1%), Cefaperazone/Sulbactum (47.4%) and Cefepime (44%). Conclusions: MDR P. aeruginosa isolates show a progressive trend as compared to previous studies. The increased resistance pattern of isolates to multiple drugs was noteworthy. Keywords: P. aeruginosa; Multidrug resistance Introduction Pseudomonas aeruginosa is a non-fermenter, pleomorphic gram negative rod. It is ubiquitous in nature i.e. it is widely distributed in nature as well as in the hospital environment and thus it is a prevalent cause of nosocomial infections, particularly amongst patients on ventilator support in intensive care units and high dependency units 1 .In the United States P. aeruginosa is one of the most common causative pathogens for hospital acquired infections ranging from urinary tract infections to bacteremia 2-3 . Patients that are infected with drug resistant and multidrug resistant (MDR) P.aeruginosa have a 34% mortality compared to 22% mortality when infected with drug susceptible P.aeruginosa 4 . Resistant P.aeruginosa can also be considered as a marker for increased in-hospital mortality 4 . Patients who have long hospital stays, require ventilator support and have previously used antibiotics are at risk of developing ventilator associated pneumonia (VAP) 5-7 . VAP is mostly caused by multidrug resistant Pseudomonas aeruginosa and other multidrug resistant organisms, such as E.Coli, K.pneumoniae and Acinetobacter species 6-8 . Currently it is seen that MDR P.aeruginosa is evolving 9 . P.aeruginosa is a complicated pathogen due to the risk of emergence of resistance during treatment 10 . MDR P. aeruginosa is defined as isolates which are resistant to at least three drugs of the following classes: B- Lactams, Carbapenems, Aminoglycosides and Fluoroquinolones 11 . MDR P.aeruginosa produces inactivating enzymes such as extended spectrum beta lactamases and metalobetalactamases which render it resistant to the Beta lactam and Carbapenem group of drugs 12 . When patients are provided with initial therapy which is insufficient in covering resistant or MDR P.aeruginosa, it leads to poor clinical outcomes, high costs and extended hospitalization 13 . This study was aimed at observing the pattern of P. aeruginosa in the ICU and HDU departments of Ziauddin Hospital.