Antimicrobial-Resistant Pathogens in Intensive Care Units in Canada: Results of the Canadian National Intensive Care Unit (CAN-ICU) Study, 2005-2006

Abstract

, 19 medical centers collected 4,180 isolates recovered from clinical specimens from patients in intensive care units (ICUs) in Canada. The 4,180 isolates were collected from 2,292 respiratory specimens (54.8%), 738 blood specimens (17.7%), 581 wound/tissue specimens (13.9%), and 569 urinary specimens (13.6%). The 10 most common organisms isolated from 79.5% of all clinical specimens were methicillin-susceptible Staphylococcus aureus (MSSA) (16.4%), Escherichia coli (12.8%), Pseudomonas aeruginosa (10.0%), Haemophilus influenzae (7.9%), coagulase-negative staphylococci/Staphylococcus epidermidis (6.5%), Enterococcus spp. (6.1%), Streptococcus pneumoniae (5.8%), Klebsiella pneumoniae (5.8%), methicillin-resistant Staphylococcus aureus (MRSA) (4.7%), and Enterobacter cloacae (3.9%). MRSA made up 22.3% (197/884) of all S. aureus isolates (90.9% of MRSA were health care-associated MRSA, and 9.1% were community-associated MRSA), while vancomycin-resistant enterococci (VRE) made up 6.7% (11/255) of all enterococcal isolates (88.2% of VRE had the vanA genotype). Extended-spectrum ␤-lactamase (ESBL)-producing E. coli and K. pneumoniae occurred in 3.5% (19/536) and 1.8% (4/224) of isolates, respectively. All 19 ESBL-producing E. coli isolates were PCR positive for CTX-M, with bla CTX-M-15 occurring in 74% (14/19) of isolates. For MRSA, no resistance against daptomycin, linezolid, tigecycline, and vancomycin was observed, while the resistance rates to other agents were as follows: clarithromycin, 89.9%; clindamycin, 76.1%; fluoroquinolones, 90.1 to 91.8%; and trimethoprim-sulfamethoxazole, 11.7%. For E. coli, no resistance to amikacin, meropenem, and tigecycline was observed, while resistance rates to other agents were as follows: cefazolin, 20.1%; cefepime, 0.7%; ceftriaxone, 3.7%; gentamicin, 3.0%; fluoroquinolones, 21.1%; piperacillin-tazobactam, 1.9%; and trimethoprim-sulfamethoxazole, 24.8%. Resistance rates for P. aeruginosa were as follows: amikacin, 2.6%; cefepime, 10.2%; gentamicin, 15.2%; fluoroquinolones, 23.8 to 25.5%; meropenem, 13.6%; and piperacillin-tazobactam, 9.3%. A multidrug-resistant (MDR) phenotype (resistance to three or more of the following drugs: cefepime, piperacillin-tazobactam, meropenem, amikacin or gentamicin, and ciprofloxacin) occurred frequently in P. aeruginosa (12.6%) but uncommonly in E. coli (0.2%), E. cloacae (0.6%), or K. pneumoniae (0%). In conclusion, S. aureus (MSSA and MRSA), E. coli, P. aeruginosa, H. influenzae, Enterococcus spp., S. pneumoniae, and K. pneumoniae are the most common isolates recovered from clinical specimens in Canadian ICUs. A MDR phenotype is common for P. aeruginosa isolates in Canadian ICUs.

Gram-negative bacilli causing infections in an intensive care unit of a tertiary care hospital in Istanbul, Turkey

“…Other studies reported similar resistance rates of P. aeruginosa [24,25]. In contrast to our results, the resistance rates of A. baumannii and P. aeruginosa are low in many developed countries [2,17]. P. aeruginosa and A. baumannii isolated from centers in the United States in the MYSTIC program (1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008) were characterized by higher susceptibilities to meropenem 85.4% and 45.7%, respectively [28].…”

“…The spectrum of pathogens in ICUs may change from country to country with time and by hospital, type of ICU, and specific patient population [15][16][17][18][19][20].…”

Antibacterial activity of amphiphilic tobramycin

“…Tobramycin, kanamycin-A and neomycin-B were purchased from Sigma Aldrich Canada Ltd (Oakville, Ontario, Canada). 10 …”

“…10 Stock solutions of amphiphilic aminoglycosides were prepared to a concentration of 512 mg ml À1 in water. Organisms were subcultured and isolated on blood agar, suspended in 3 ml of Mueller-Hinton broth at the turbidity of a 0.5 M McFarland standard, and diluted to approximately 10 5 CFU ml À1 before introduction into tubes containing serially diluted lipopeptide antibiotic in Mueller-Hinton broth.…”

Risk factors for methicillin-resistant Staphylococcus aureus bacteremia: A multicenter matched case-control study

“…MRSA bacteremia emergence among ICU patients has been associated with several factors, which can be classified according to three groups: a) those related to the microorganisms, primarily the spread of resistant clones (8); b) those associated with the host, which include age, sex, presence of comorbidities (particularly chronic illnesses), previous use of antibiotics and invasive devices (9)(10)(11)(12), and c) the characteristics of hospital and community environments (9,11,13), particularly previous use of antibiotics given the high risk associated with this factor and the control of crosstransmission of microorganisms.…”