346 Journal of the College of Physicians and Surgeons Pakistan 2015, Vol. 25 (5): 346-349 INTRODUCTION The genus Acinetobacter are non-fermentative and non- motile, gram-negative coccobacilli, which comprises 27 known and several unnamed provisional species. Clinically, Acinetobacter baumannii (Ab) is most often identified as the cause of infection, but other clinically significant species include A. johnsonii, A. iwoffii, A. radioresistens, A. calcoaceticus, A. haemolyticus, A. lwoffii and A. junii. 1 A. baumannii is an opportunistic pathogen of emerging importance in the clinical settings and responsible for upto 20% of infections in intensive care units around the globe. 2 The majority of reported clinical cases involved ventilator associated pneumonia/ pulmonary infections, bloodstream infections, skin and soft tissue infections including burn and surgical wound infections, endocarditis, meningitis and urinary tract infec- tions. Furthermore, infections caused by Acinetobacter are not limited to the hospital settings and reports have emerged unfolding cases involving otherwise healthy individuals of all age groups, occurring in community settings, following natural disasters and during wars. 1-3 Multidrug Resistant Acinetobacter baumannii (MDR-Ab) is one of the most important healthcare-associated pathogens and are increasingly reported around the globe. Due to its remarkable abilities to colonize patients as well as healthcare associated environment, cross- transmission and prolonged environmental survival, it causes healthcare associated outbreaks. 4,5 Treatment of infections due to this pathogen is becoming a serious clinical concern, since A. baumannii is showing exten- sive resistance to many of the currently used antibiotics including cephalosporins, aminoglycosides, quinolones and carbapenems. A. baumannii is of particular concern due to its predilection to acquire antibiotic resistance determinants. 2 A. baumannii has the capacity to develop antimicrobial resistance by various mechanisms, which is mostly related to mobile genetic elements, such as insertion sequences, plasmids and antibiotic resistant islands. 6 Nosocomial MDR-Ab infection most commonly occurs in intensive care units (ICUs). Outbreaks in ICUs due to MDR-Ab have been reported to be associated with ORIGINAL ARTICLE Frequency and Antimicrobial Susceptibility Pattern of Acinetobacter Species Isolated from Pus and Pus Swab Specimens Muhammad Fayyaz 1 , Inam Ullah Khan 2 , Aamir Hussain 3 , Irfan Ali Mirza 4 , Shamshad Ali 5 and Nauman Akbar 1 ABSTRACT Objective: To evaluate the frequency and antimicrobial susceptibility pattern of Acinetobacter species isolated from pus and pus swab specimens at a tertiary care setting. Study Design: Cross-sectional observational study. Place and Duration of Study: Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from July 2008 to July 2012. Methodology: Data regarding positive culture and antimicrobial sensitivity pattern was retrieved from the pus and pus swab culture records of the Microbiology Department, AFIP, Rawalpindi. Only those pus and pus swab specimens which yielded the growth of Acinetobacter species were included in the study. Results: Out of 2781, 1848 were of pure pus while 933 were pus swab specimens. Out of 2538 culture positive isolates, 276 (10.9%) were identified as Acinetobacter species. Among 276 Acinetobacter spp., 245 (88.8%) were Acinetobacter baumannii and 31 (11.2%) were Acinetobacter johnsonii. Male/female ratio of the affected patients was 5.6:1. Doxycycline was the most sensitive antibiotic to which 45% of the tested isolates were sensitive. Sensitivity to all other antimicrobials was 15% or less. Conclusion: About 11% of soft tissue and wound infections are caused by Acinetobacter species in our set up particularly in male. Doxycycline was the most sensitive antibiotic. Sensitivity to all other antimicrobials was 15% or less. In vitro sensitivity to carbapenems is very low. Key Words: Acinetobacter spp. Nosocomial infection. Pus specimens. Wound infection. Soft tissue. 1 Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi. 2 Department of Pathology, Combined Military Hospital, Tall. 3 Department of Pathology, Combined Military Hospital, Peshawar Cantt. 4 Department of Pathology, PNS Shifa, Karachi. 5 Department of Pathology, Combined Military Hospital, Mailsi. Correspondence: Dr. Aamir Hussain, Department of Microbiology, Combined Military Hospital, Peshawar Cantt. E-mail: aamir_1766@hotmail.com Received: November 01, 2014; Accepted: March 27, 2015.