Antibiotic Resistance Patterns of Bacterial Isolates in Adult Intensive Care Unit at Nizwa Hospital, Oman

Background and Objectives: Infection is a commonly encountered problem for patients in intensive care units (ICUs) and Multidrug-resistant (MDR) bacterial infection is predominant. The aim of this study was to detect the frequency of different bacterial isolates and their antibiotic susceptibility pattern from patients admitted to adult ICU in a 5 year period from January 2008 to December 2012 at Nizwa hospital, Oman.

Materials and Methods: Different microbiological samples were collected and analyzed by routine conventional methods at microbiology section, laboratory department; Nizwa hospital. Antibiotic susceptibility (ABS) test was done using modified Kirby-Bauer disk diffusion method as per Clinical and Laboratory Standards Institute (CLSI) guidelines.

Results: Total (3930) clinical samples were processed, out of which 12.8% (504/3930) showed evidence of infection, 73.6% (371/504) were Gram-negative bacteria, 22.8% (115/504) were Gram-positive and 3.6% (18/504) were Candida species. Respiratory tract infection was the most common site of infection. Among the isolates, the most commonly found microorganism was Pseudomonas aeruginosa in respiratory samples, pus and wound infection, However Klebsiella spp. and Escherichia coli were predominant in urinary tract infection. Coagulase negative Staphylococcus was the predominant in blood. Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli, Klebsiella spp. and Proteus occurred in 43.2% (29/67), 28.6% (18/63) and 45.5% (5/11) of total Escherichia coli, Klebsiella spp. and Proteus isolates. While 16.6% of Staphylococcus aureus isolates were Methicillin Resistant Staphylococcus aureus (MRSA).

Conclusion: Adult ICUs are faced with the increasingly rapid emergence and spread of antibiotic-resistant bacteria. Excellent antibiotic policy and infection control implementation are important priorities for these critically ill patients.