Antibiotic Consumption and Development of Resistance among Gram-Negative Bacilli in Intensive Care Units in Oman

Abstract

Since the discovery of antimicrobial agents, microorganisms have developed virtually unlimited resistance to them.1 Hospitals and particularly intensive care units are an important breeding ground for the development of antibiotic-resistant bacteria. This is the consequence of heavy antibiotic use. In addition, a high-density patient population in frequent contact with health care staff and the attendant risk of cross-infection contributes to the spread of antibiotic-resistant micro-organisms. This in turn increases the morbidity and mortality associated with infections, and contributes to rising costs of health care.2,3 The aim of this study was to investigate the prevalence of antibiotic resistance among gram-negative bacteria in relation to antibiotic use in the intensive care unit (ICU) at the Royal Hospital, the main referral hospital in Oman. Materials and MethodsThe Royal Hospital is a 630-bed tertiary care hospital consisting of major medical and surgical departments, in addition to specialized units such as intensive care, neonatal, renal, cardiac and oncology. The intensive care unit (ICU) at the Royal Hospital is a general unit admitting both medical and surgical patients, and has a capacity of 12 beds divided between adults and pediatrics. Specimen Collection and Identification of IsolatesOne hundred consecutive gram-negative bacterial isolates from different sites were collected from patients admitted to the adult ICU at the Royal Hospital. The clinical significance of the isolates was confirmed by analysis of patients' records and discussion with the treating clinician. All bacterial strains were identified by their colonial morphology, gram reaction, the oxidized and other biochemical reactions as performed by either API 20E, or API 20NE (bioMerieux, France). Susceptibility TestingThe susceptibilities of the strains to 12 antibiotics (co-amoxiclav, cefuroxime, cefotaxime, ceftriaxone, ceftazidime, aztreonam, piperacillin, piperacillin/tazobactam, imipenem, gentamicin, amikacin, and ciprofloxacin) were performed by determining the minimum inhibitory concentration (MIC), using the E-test (AB BIODISK, Sweden), with E. coli NCTC 10418 and P. aeruginosa NCTC 10662 as controls. The interpretation standards for MICs of the NCCLS were used to determine antibiotic susceptibilities. 4 To detect extended spectrum β-lactamases (ESBL), ceftazidime-resistant strains of E. coli and Klebsiella spp. were further tested against ceftazidime/clavulanic acid. Isolates with a reduction of ceftazidime MIC by >3 two-fold dilutions in the presence of clavulanic acid were considered ESBL producers, and thus resistant to other cephalosporins. Antibiotic ConsumptionThe quantities of antibiotics consumed in the ICU during the period of the study were obtained from the hospital pharmacy records, and the numbers of the patients discharged were obtained from the hospital records. The estimated days of antibiotic treatment were calculated from the antibiotic daily dose, the total amount consumed and the number of patients who lef...

Antimicrobial susceptibility patterns among bacteria isolated from intensive care units of the largest teaching hospital at the northwest of Iran

“…These findings are in agreement with those of the study conducted by Streit et al in North America (Streit et al, 2004). However, in a report from Oman, Escherichia coli and Pseudomonas aeruginosa were the pathogens most commonly found in the urinary and respiratory tracts of ICU patients (Al-Lawati, Crouch, Elhag, 2000). Whereas, Klebsiella and Pseudomonas were the microorganisms most commonly found in the urine of patients admitted to the ICU of Imam Khomeini Hospital in Tehran (Hadadi et al, 2008).…”

“…Moreover, the resistance rate to cephalosporins (79.5%-87.8%) was comparable to that in Iran (Hadadiet al, 2008), but higher than reported in foreign studies (Gunseren et al, 1999;Al-Lawati, Crouch, Elhag, 2000;Glupczynski et al, 2001;Patzer, Dzierzanowska,Turner, 2002;Gonlugur et al, 2004;Karlowsky et al, 2003;Meric et al, 2005). C u r r e n t r e s u l t s a l s o s h o w e d t h a t 2 5 .…”

Antimicrobial Susceptibility Pattern of Six Threatening Pathogens at Mofid Children’s Hospital, Tehran, Iran

“…The rates of imipenem susceptibility in our study were different from those reported in previous studies showing that the isolates of Klebsiella spp. and E. coli were fully susceptible to imipenem (30,31). The cause of these differences may be due to higher carbapenem prescription for patients in our study hospital and subsequently the emergence of carbapenem-resistant strains.…”

Infeksi Bakteri Gram Negatif di ICU Anak: epidemiologi, manajemen antibiotik dan pencegahan

“…7,8 Bila antibiotik diberikan berlebihan, tidak adekuat, monoton (satu jenis terus menerus) maka akan mengurangi efektifitasnya sehingga menimbulkan resistensi terutama bakteri Gram negatif. 1,9 Bakteri Gram negatif yang paling sering diisolasi di ICU anak adalah Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, dan Klebsiella pneumoniae. Sumber bakteremia tersering adalah infeksi saluran kemih dan pneumonia.…”