RICHARD OMOREGIE

The rise of antimicrobial resistance (AMR) poses a critical threat to effective infection management, with Escherichia coli recognized as a key contributor due to its role in both community and hospital-acquired infections of particular concern are extended- spectrum β-lactamase (ESBL)-producing strains, which hydrolyze third-generation cephalosporins and are frequently associated with multidrug resistance. This study investigated the relationship between the Multiple Antibiotic Resistance (MAR) index and ESBL production among E. coli isolates obtained from clinical specimens at the
University of Benin Teaching Hospital (UBTH). A total of 51 isolates were analyzed
using standard microbiological and susceptibility techniques. ESBL production was confirmed in 9 isolates (17.6%), all from urine samples, consistent with previous reports that highlight urinary tract infections as the leading source of ESBL-producing E. coli. The MAR index values ranged from 0.1 to 1.0, with 31.4% of isolates
exhibiting MAR = 1.0, underscoring the high antibiotic selection pressure in hospital environments. Although ESBL production was more frequent at higher MAR values, statistical analysis showed no significant correlation (p = 0.1677). This contrasts with
findings from other regions where ESBL producers consistently demonstrate elevated MAR indices. The presence of multidrug-resistant ESBL-producing E. coli in UBTH underscores the urgent need for robust antimicrobial stewardship and infection control strategies to mitigate treatment failures and resistance dissemination in Nigeria.

Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen of major clinical concerndue to its adaptability, virulence determinants, and increasing multidrug resistance (MDR). It isaleading cause of urinary tract infections, pneumonia, wound infections, and septicemia, particularly in hospitalized and immunocompromised patients. Its resistance mechanisms includeintrinsic traits such as efflux pumps and β-lactamase production, acquired carbapenemases, andadaptive tolerance via biofilm formation, making it one of the World Health Organization’scritical priority pathogens. This cross-sectional study was conducted at the University of BeninTeaching Hospital (UBTH) to evaluate the antibiotic resistance profile of Pseudomonasaeruginosa across clinical specimens. The clinical isolates collected were processedusingstandard microbiological and biochemical techniques. Susceptibility testing was done, withresults interpreted using CLSI guidelines. Data were statistically analyzed to assess prevalenceand resistance associations. Out of 365 isolates, 34 (9.32%) yielded Pseudomonas aeruginosa, with urine as the most common source. Isolates were more frequent in medical wards, thoughnosignificant age-related differences were noted. Resistance was extremely high: 100%to cefepime, 97.1% to cefotaxime, and 85.3% to ciprofloxacin, while ofloxacin (50%) and meropenem(52.9%) showed comparatively lower resistance. In conclusion, Pseudomonas aeruginosaisolates from UBTH exhibited high MDR levels, limiting therapeutic options. Routinesurveillance, antimicrobial stewardship, and infection control measures are essential tocurbresistance, while novel therapies such as phage treatment and β-lactam/β-lactamase inhibitorcombinations may offer future solutions