Reinvigorating the efficacy of Temocillin against ESBL and Amp C producing gram negative bacteria

Objective: To evaluate the in vitro efficacy of temocillin against Extended spectrum β- lactamase (ESBL) and AmpC producing gram negative bacteria (GNB) by determining its minimum inhibitory concentration (MIC). Material and Methods: This descriptive cross-sectional study was conducted in the department of Microbiology at Fauji foundation hospital Rawalpindi (FFH) Pakistan from Jan 2018 to Feb 2023. ESBL and AmpC producing GNB from various clinical samples were collected. Temocillin MIC was determined using E-test method. Results: Out of 170 clinical isolates, there were 107 (62.9%) ESBL and 63 (37.1%) Amp C producing GNB. Frequency along with percentage of sensitive and resistant ESBL producers according to MIC of temocillin was 103 (96.3%) and 4 (3.7%) respectively, whereas frequency and percentage of sensitive and resistant Amp-C producers according to MIC of temocillin was 57 (90.5%) and 6 (9.5%) respectively. Among cases with age less than 50 years, sensitive ESBL and Amp C were 69 (95.8%) and 28 (87.5%) respectively. For above 50 age group it was 34(97.1%) and 29 (93.5%). Among female cases, 66 (95.7%) of ESBL-producing isolates and 21 (84.0%) of AmpC-producing isolates were sensitive to temocillin. MIC 50 of temocillin against ESBL and AmpC producing GNB came out to be 4ug/ml and MIC 90came out to be 6ug/ml. Conclusion: Temocillin demonstrated favorable in vitro activity against ESBL and AmpC producing GNB and may be a suitable choice for treating infections by these organisms. Keywords: Temocillin, Extended spectrum β-lactamase, AmpC, Minimum inhibitory concentration, Gram negative bacilli