Background and Objectives: This study was designed to determine the in vitro efficacy of mecillinam against extended spectrum beta lactamse producing Enterobacterales. Materials and Methods: After proper permission from Ethical Review Committee of the Institute, all samples yielding growth of ESBL producingEnterobacterales were part of the study and were processed according to routine microbiological procedures. Routine antibiotic sensitivity testing was done onMuller Hinton Agar by Modified Kirby Bauer Method. All Gram negative isolates were subjected to concomitant detection of ESBL production by doubledisc synergy method. All ESBL producers were then subjected to the mecillinam Minimum Inhibitory Concentration (MIC) determination by E test. The results were interpreted as per CLSI Guidelines. Results: A total of 120 ESBL producing Enterobacterales isolates were included in the study. The mean age of patients with ESBL infection was 45 ± 18.7years. There were 44% male and 55% female patients. Majority of the ESBL producing Enterobacterales were isolated from urine samples (56%), followed bypus. Among the isolated organisms, Escherichia coli (45%) was the most frequently isolated organism followed by Klebsiella spp. (22%). Overall 83% of theisolates turned out to be sensitive to mecillinam. MIC50 of mecillinam against ESBL producing Gram negative rods (GNR) turned out to be 1 ug/ml and MIC90 turned out to be 2 ug/ml. Conclusion: Mecillinam shows good in vitro efficacy against ESBL producing Enterobacterales in our study. Further studies with more sample size and from diverse areas across the country should be done to evaluate its efficacy.

Abstract Objectives: To determine frequency of Endogenous Methicillin Resistant Staphylococcus aureus (MRSA) in pre operative patients and its frequency in Surgical Site Infections (SSIs) Post operatively. Methods: It was a descriptive cross sectional conducted at Department of Microbiology, Fauji Foundation Hospital Rawalpindi (FFH), Pakistan. Samples were collected from 1st November-31st May 2018. Total 75 samples were collected during the period. Consecutive non-probability sampling technique was utilized. Specimens were collected from nose, axilla and groin of preoperative patients. Methicillin Resistant Staphylococcus aureus was identified if only isolated from these sites. Patients were followed till his/her discharge from the hospital and if they developed infection post operatively, pus specimen from infected site was also collected and identified.Results: Out of 75 specimen preoperatively, 14.7% (n=11) were identified as endogenous MRSA. From these, 44% (n=33) developed Surgical site infections (SSIs), among them 57% (n=19) were MRSA (09 endogenous, 10 exogenous), 21.2% (n=7) were Escherichia coli, 9.1% (n=3) were Klebsiella pneumoniae, 9.1% (n=3) were Enterococcus faecalis and 3% (n=1) was Methicillin Sensitive Staphylococcus aureus. Conclusion:  The results of this study determined that Endogenous Methicillin Resistant Staphylococcus aureus (MRSA) could be isolated from patients going for surgery if microbiological screening was done at the time of admission. This could prevent patients from Surgical Site Infection Post operatively by these endogenous MRSA. This search and wipe out strategy is able to curtail the events of outbreak, reduce hospital stay and decrease budget of the hospital by providing guidance in choice of empirical therapy for infection. Continuous...