en علوم پایه پزشکی Basic medical sciences پژوهشي Research <div style="text-align: justify;"><strong>Introduction:</strong> Antimicrobial resistance in bacterial pathogens is associated with high morbidity and mortality. We aimed to evaluate antibiotic resistance and &beta;-lactamase production in clinical isolates of a tertiary care hospital in Central India. <strong>Materials and Methods:</strong> Clinical isolates (n=6472 isolates) from patients with infection were identified using standard microbiological techniques. Antibiotic susceptibility testing was performed according to the CLSI guidelines using the Kirby-Bauer disc diffusion technique. AmpC production in <em>Enterobacteriaceae</em> isolates was tested in screening test. Cloxacillin combined disc diffusion test was performed for both inducible and non-inducible AmpC using cefoxitin disc with and without cloxacillin. Metallo-&beta;-lactamase production in <em>Enterobacteriaceae</em> isolates was tested in screening test (positive= zone diameter of <u><</u> 21 mm for meropenem). Non-fermenting Gram-negative isolates were tested by combined disc test using imipenem and imipenem-EDTA discs. <strong>Results: </strong>Majority of the bacteremia cases were caused by <em>Staphylococcus aureus</em> (43.13%), non-fermenting spp. (27.44%) and coagulase-negative staphylococci (11.76%). <em>Escherichia coli </em>(55.85%) was the main cause of urinary tract infection followed by <em>Acinetobacter</em> spp. (11.71%) and <em>Klebsiella pneumoniae</em> (10.36%). No resistance to linezolid was seen in Gram-positive isolates. Frequency of vancomycin-resistance was about 9% in <em>Enterococcus</em> spp. Methicillin resistance was seen in 19% of <em>S. aureus</em> isolates. <em>Enterobacteriaceae</em> and <em>Citrobacter freundii</em> isolates were completely resistant to aminopenicillin, first and second-generation cephalosporins and cefamycin. Moreover, <em>Klebsiella</em> isolates were resistant to aminopenicillin. <em>Enterobacteriaceae</em> isolates showed resistance to aminopenicillin (89.87%), cephalosporins (54-90%) and cephamycin (37-45%). <em>E. coli</em> isolates were sensitive to PIT (87-96%) and imipenem (99.68-100%). ESBL production was seen in 166 <em>Enterobacteriaceae</em> isolates (30.24%) in DDST and CPCT. AmpC production was seen in 15 (2.73%) <em>Enterobacteriaceae</em> isolates.&nbsp; Total &beta;-lactamase production was found in 19.23% of the isolates tested. The frequency of &beta;-lactamase production was highest in <em>K. pneumoniae</em> (51.67%). Co-production of &beta;-lactamases was not observed. <strong>Conclusions:</strong> It is necessary to closely monitor drug resistance and &beta;-lactamase production. Moreover, it is recommended to perform routine &beta;-lactamase testing in microbiology laboratories for determining prevalence of antibiotic resistance and controlling their spread.</div> Antibiotic Resistance, ESBL, β-lactamase, Enterobacteriaceae 1 5 http://jcbr.goums.ac.ir/browse.php?a_code=A-10-59-3&slc_lang=en&sid=1 Vaibhavi Vijay Nanoty ویجی نانوتی 10031947532846001137 10031947532846001137 No 1. Department of Microbiology, Government Medical College Akola, Collector Office Road, Near Ashok Vatika, Akola, Maharashtra, India Gopal Nandlal Agrawal گوپال آگرووال 10031947532846001138 10031947532846001138 Yes 2. Department of Microbiology, Government Medical College Nagpur, Hanuman Nagar, Nagpur, Maharashtra, India Supriya Sanjay Tankhiwale سنجای تنخیوال 10031947532846001139 10031947532846001139 No