scholarly journals Prevalence of Antimicrobial-Resistant Pathogens in Canadian Hospitals: Results of the Canadian Ward Surveillance Study (CANWARD 2007)

2009 ◽  
Vol 20 (suppl a) ◽  
pp. 9A-19A ◽  
Author(s):  
George G Zhanel ◽  
James A Karlowsky ◽  
Mel DeCorby ◽  
Kim A Nichol ◽  
Aleksandra Wierzbowski ◽  
...  

BACKGROUND: Canadian hospitals as well as hospitals worldwide are increasingly faced with antibiotic-resistant pathogens, including multidrug-resistant (MDR) strains. OBJECTIVES: To assess the prevalence of pathogens, including the resistance genotypes of methicillin-resistantStaphylococcus aureus(MRSA), vancomycin-resistant enterococci (VRE) and extendedspectrum beta-lactamase (ESBL)-producingEscherichia coliin Canadian hospitals, as well as their antimicrobial resistance patterns. MEtHODS: Bacterial isolates were obtained between January 1, 2007, and December 31, 2007, inclusive, from patients in 12 hospitals across Canada as part of the Canadian Ward Surveillance Study (CANWARD 2007). Isolates were obtained from bacteremic, urinary, respiratory and wound specimens and underwent antimicrobial susceptibility testing. Susceptibility testing was assessed using the Clinical and Laboratory Standards Institute broth microdilution method. RESULTS: In total, 7881 isolates were recovered from clinical specimens of patients attending Canadian hospitals. The 7881 isolates were collected from respiratory (n=2306; 29.3%), blood (n=3631; 46.1%), wounds/tissue (n=617; 7.8%) and urinary (n=1327; 16.8%) specimens. The 10 most common organisms isolated from 76.5% of all clinical specimens wereE coli(21.6%), methicillin-susceptibleS aureus(13.9%),Streptococcus pneumoniae(8.9%),Pseudomonas aeruginosa(8.0%),Klebsiella pneumoniae(5.8%), MRSA (4.9%),Haemophilus influenzae(4.3%), coagulase-negative staphylococci/taphylococcus epidermidisS (4.0%),Enterococcus species(3.0%) andEnterobacter cloacae(2.1%). MRSA made up 26.0% (385 of 1480) of allS aureus(genotypically, 79.2% of MRSA were health care-associated MRSA and 19.5% were community-associated MRSA), and VRE made up 1.8% of all enterococci (62.5% of VRE had thevanA genotype). ESBLproducingE colioccurred in 3.4% ofE coliisolates. The CTX-M type was the predominant ESBL, with CTX-M-15 as the predominant genotype. With MRSA, no resistance was observed to daptomycin, linezolid, tigecycline and vancomycin, while resistance rates to other agents were: clarithromycin 91.4%, clindamycin 61.8%, fluoroquinolones 88.6% to 89.6%, and trimethoprim-sulfamethoxazole 12.2%. WithE coli, no resistance was observed to ertapenem, meropenem and tigecycline, while resistance rates to other agents were: amikacin 0.1%, cefazolin 14.2%, cefepime 2.0%, ceftriaxone 8.9%, gentamicin 10.6%, fluoroquinolones 23.6% to 24.5%, piperacillin-tazobactam 1.3% and trimethoprim-sulfamethoxazole 26.6%. Resistance rates withP aeruginosawere: amikacin 7.6%, cefepime 11.7%, gentamicin 20.8%, fluoroquinolones 23.4% to 25.1%, meropenem 8.1% and piperacillin- tazobactam 7.3%. A MDR phenotype (resistance to three or more of cefepime, piperacillin-tazobactam, meropenem, amikacin or gentamicin, and ciprofloxacin) occurred frequently inP aeruginosa(10.6%) but uncommonly inE coli(1.2%),K pneumoniae(1.5%),E cloacae(0%) orH influenzae(0%). CONCLUSIONS:E coli,S aureus(methicillin-susceptible and MRSA),S pneumoniae,P aeruginosa,K pneumoniae,H influenzaeandEnterococcusspecies are the most common isolates recovered from clinical specimens in Canadian hospitals. The prevalence of MRSA was 26.0% (of which genotypically, 19.5% was community-associated MRSA), while VRE and ESBL-producingE colioccurred in 1.8% and 3.4% of isolates, respectively. A MDR phenotype is common withP aeruginosain Canadian hospitals.

2010 ◽  
Vol 54 (11) ◽  
pp. 4684-4693 ◽  
Author(s):  
George G. Zhanel ◽  
Melanie DeCorby ◽  
Heather Adam ◽  
Michael R. Mulvey ◽  
Melissa McCracken ◽  
...  

ABSTRACT A total of 5,282 bacterial isolates obtained between 1 January and 31 December 31 2008, inclusive, from patients in 10 hospitals across Canada as part of the Canadian Ward Surveillance Study (CANWARD 2008) underwent susceptibility testing. The 10 most common organisms, representing 78.8% of all clinical specimens, were as follows: Escherichia coli (21.4%), methicillin-susceptible Staphylococcus aureus (MSSA; 13.9%), Streptococcus pneumoniae (10.3%), Pseudomonas aeruginosa (7.1%), Klebsiella pneumoniae (6.0%), coagulase-negative staphylococci/Staphylococcus epidermidis (5.4%), methicillin-resistant S. aureus (MRSA; 5.1%), Haemophilus influenzae (4.1%), Enterococcus spp. (3.3%), Enterobacter cloacae (2.2%). MRSA comprised 27.0% (272/1,007) of all S. aureus isolates (genotypically, 68.8% of MRSA were health care associated [HA-MRSA] and 27.6% were community associated [CA-MRSA]). Extended-spectrum β-lactamase (ESBL)-producing E. coli occurred in 4.9% of E. coli isolates. The CTX-M type was the predominant ESBL, with CTX-M-15 the most prevalent genotype. MRSA demonstrated no resistance to ceftobiprole, daptomycin, linezolid, telavancin, tigecycline, or vancomycin (0.4% intermediate intermediate resistance). E. coli demonstrated no resistance to ertapenem, meropenem, or tigecycline. Resistance rates with P. aeruginosa were as follows: colistin (polymyxin E), 0.8%; amikacin, 3.5%; cefepime, 7.2%; gentamicin, 12.3%; fluoroquinolones, 19.0 to 24.1%; meropenem, 5.6%; piperacillin-tazobactam, 8.0%. A multidrug-resistant (MDR) phenotype occurred frequently in P. aeruginosa (5.9%) but uncommonly in E. coli (1.2%) and K. pneumoniae (0.9%). In conclusion, E. coli, S. aureus (MSSA and MRSA), P. aeruginosa, S. pneumoniae, K. pneumoniae, H. influenzae, and Enterococcus spp. are the most common isolates recovered from clinical specimens in Canadian hospitals. The prevalence of MRSA was 27.0% (of which genotypically 27.6% were CA-MRSA), while ESBL-producing E. coli occurred in 4.9% of isolates. An MDR phenotype was common in P. aeruginosa.


2008 ◽  
Vol 52 (4) ◽  
pp. 1430-1437 ◽  
Author(s):  
George G. Zhanel ◽  
Mel DeCorby ◽  
Nancy Laing ◽  
Barb Weshnoweski ◽  
Ravi Vashisht ◽  
...  

ABSTRACT Between 1 September 2005 and 30 June 2006, 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 β-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.


2020 ◽  
Vol 22 (1) ◽  
pp. 40-45
Author(s):  
N.V. Ivanchik ◽  
M.V. Sukhorukova ◽  
А.N. Chagaryan ◽  
А.V. Dekhnich ◽  
R.S. Kozlov ◽  
...  

Objective. To evaluate antimicrobial resistance patterns of clinical Streptococcus pyogenes isolates from different regions of Russia during 2014–2017. Materials and Methods. A total of 792 clinical S. pyogenes isolates from 14 Russian cities were included in the study. Susceptibility testing was performed using reference broth microdilution method (ISO 207761:2006). Susceptibility testing results were interpreted using EUCAST v.10.0 breakpoints. Results. Penicillin G was active against all tested isolates with the MIC50–90 values of 0.016 mg/l and the highest MIC value of 0.25 mg/l. No resistance to linezolid, tedizolid and vancomycin were observed. Respiratory fluoroquinolones, moxifloxacin and levofloxacin, showed a high activity with the only 0.3% and 0.8% of resistant isolates, respectively. Almost all isolates (99.9%) were susceptible to trimethoprim/ sulfamethoxazole. The resistance rates to 14- and 15-membered macrolides varied from 12.1% to 17.2%. The only 2.4% of isolates were resistant to clindamycin. Resistance to chloramphenicol was 6.1%, to tetracycline – 17.2%. Conclusions. The comparison of this study results with the previously published Russian data on antimicrobial resistance of S. pyogenes shows there were no significant changes in the susceptibility of this pathogen over the past two decades, with the exception of macrolides. The growing resistance to 14and 15-membered macrolides raises a question on the further use of this antibiotic class for the empiric treatment of streptococcal infections in Russia.


1999 ◽  
Vol 10 (2) ◽  
pp. 122-127 ◽  
Author(s):  
Donald E Low ◽  
Joyce de Azavedo ◽  
Canadian Bacterial Surveillance Network ◽  
Ross Davidson

OBJECTIVE: To determine the in vitro activity of cefepime against multidrug-resistant Gram-negative bacilli and Gram-positive cocci obtained from an ongoing cross-Canada surveillance study.DESIGN: Clinical isolates of aerobic Gram-negative bacilli with inducible and constitutive chromosomally mediated cephalosporinases, viridans group streptococci andStreptococcus pneumoniaewere collected from laboratories serving hospitals, nursing homes and physician offices in the community from across Canada during 1996 and 1997. Laboratories were asked to submit only clinically relevant nonduplicate isolates for susceptibility testing. In vitro antimicrobial susceptibility testing was carried out on all isolates of Gram-negative and viridans group streptococci.S pneumoniaewere characterized as penicillin susceptible, intermediately resistant or highly resistant. Nonsusceptible isolates were defined as being intermediately or highly resistant (minimal inhibitory concentrations [MIC] greater than 0.06 mg/L). Only isolates ofS pneumoniaethat were nonsusceptible to penicillin were selected for further study. MICs were determined using a microbroth dilution technique according to the National Committee of Clinical Laboratory Standards.RESULTS: A total of 727 Gram-negative bacilli samples were collected. No resistance to cefepime was detected withCitrobacter freundii,Serratia marcescens,Morganella morganiiandEnterobacterspecies. Of these strains,Enterobacterspecies andC freundiiwere the most resistant to ceftazidime, cefotaxime and ceftriaxone with MIC90Sof 32 mg/L or greater and resistance rates of 6% or greater. Resistance rates ofPseudomonas aeruginosaandAcinetobacterspecies to cefepime were 4.8% and 3%, respectively. The two organisms had similar rates of resistance to ceftazidime. Less than 3% of the Gram-negative bacilli were resistant to imipenem and meropenem. There were 153 viridans group streptococci, of which 22 (14.4%) were resistant to penicillin. Of 1287S pneumoniaesamples, 193 (15%) were nonsusceptible to penicillin. Cefepime, ceftriaxone and cefotaxime had comparable activity against all isolates of viridans group streptococci andS pneumoniae.CONCLUSIONS: Cefepime demonstrated excellent in vitro activity against Gram-negative bacilli with inducible and constitutive chromosomally mediated cephalosporinases, and had equal or superior activity versus comparator beta-lactams against all isolates of viridans group streptococci andS pneumoniae.


Antibiotics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 152 ◽  
Author(s):  
Ramona Iseppi ◽  
Alessandro Di Cerbo ◽  
Patrizia Messi ◽  
Carla Sabia

Background: We investigated the virulence factors, genes, antibiotic resistance patterns, and genotypes (VRE and ESBL/AmpC) production in Enterococci and Enterobacteriaceae strains isolated from fecal samples of humans, dogs, and cats. Methods: A total of 100 fecal samples from 50 humans, 25 dogs, and 25 cats were used in the study. MICs of nine antimicrobials were determined using the broth microdilution method. Polymerase chain reaction was used for the detection of genes responsible for antibiotic resistance (VRE and ESBL/AmpC) and virulence genes both in Enterococcus species, such as cytolysin (cylA, cylB, cylM), aggregation substance (agg), gelatinase (gelE), enterococcal surface protein (esp), cell wall adhesins (efaAfs and efaAfm), and in Enterobacteriaceae, such as cytolysin (hemolysin) and gelatinase production (afa, cdt, cnf1, hlyA, iutA, papC, sfa). Results: Enterococcus faecium was the most prevalent species in humans and cats, whereas Enterococcus faecalis was the species isolated in the remaining samples. A total of 200 Enterobacteriaceae strains were also detected, mainly from humans, and Escherichia coli was the most frequently isolated species in all types of samples. In the Enterococcus spp, the highest percentages of resistance for ampicillin, amoxicillin/clavulanate, erythromycin, tetracycline, ciprofloxacin, teicoplanin, and vancomycin were detected in cat isolates (41.6%, 52.8%, 38.9%, 23.6%, 62.5%, 20.8%, and 23.6% respectively), and in E. coli, a higher rate of resistance to cefotaxime and ceftazidime emerged in cat and dog samples, if compared with humans (75.4% and 66.0%, 80.0% and 71.4%, and 32.0% and 27.2%, respectively). Regarding the total number of enterococci, 5% and 3.4% of the strains were vancomycin and teicoplanin resistant, and the vancomycin resistance (van A) gene has been detected in all samples by PCR amplification. All the Enterobacteriaceae strains were confirmed as ESBL producers by PCR and sequencing, and the most frequent ESBL genes in E. coli strains from humans and pet samples were blaCTX-M-1 and blaCTX-M-15. Conclusions: Our results provide evidence that one or more virulence factors were present in both genera, underlining again the ability of pet strains to act as pathogens.


2009 ◽  
Vol 20 (suppl a) ◽  
pp. 20A-30A
Author(s):  
George G Zhanel ◽  
Mel DeCorby ◽  
Kim A Nichol ◽  
Aleksandra Wierzbowski ◽  
Patricia J Baudry ◽  
...  

BACKGROUND: Antimicrobial resistance is a growing problem in North American hospitals as well as hospitals worldwide. OBJECTIVES: To assess the antimicrobial susceptibility patterns of commonly used agents against the 20 most common organisms isolated from Canadian hospitals. METHODS: In total, 7881 isolates were obtained between January 1, 2007, and December 31, 2007, from 12 hospitals across Canada as part of the Canadian Ward Surveillance Study (CANWARD 2007). Of these, 6685 isolates (20 most common organisms) obtained from bacteremic, urinary, respiratory and wound specimens underwent antimicrobial susceptibility testing. Susceptibility testing was assessed using the Clinical and Laboratory Standards Institute broth microdilution method. RESULTS: The most active (based upon minimum inhibitory concentration [MIC] data only) agents against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) were dalbavancin, daptomycin, linezolid, telavancin, tigecycline and vancomycin, with MICs required to inhibit the growth of 90% of organisms (MIC90) of 0.06 μg/mL and 0.06 μg/mL, 0.25 μg/mL and 0.25 μg/mL, 4 μg/mL and 1 μg/mL, 0.25 μg/mL and 0.25 μg/mL, 0.5 μg/mL and 0.25 μg/mL, and 1 μg/mL and 2 μg/mL, respectively. The most active agents against vancomycin-resistant enterococci were daptomycin, linezolid and tigecycline with MIC90sof 2 μg/mL, 4 μg/mL and 0.12 μg/mL, respectively. The most active agents againstEscherichia coliwere amikacin, cefepime, ertapenem, meropenem, piperacillin-tazobactam and tigecycline with MIC90sof 4 μg/mL, 2 μg/mL, 0.06 μg/mL or less, 0.12 μg/mL or less, 4 μg/mL and 1 μg/mL, respectively. The most active agents against extendedspectrum beta-lactamase-producing E coli were ertapenem, meropenem and tigecycline with MIC90sof 0.12 μg/mL or less, 0.12 μg/mL or less and 1 μg/mL, respectively. The most active agents againstPseudomonas aeruginosawere amikacin, cefepime, meropenem and piperacillin-tazobactam with MIC90sof 32 μg/mL, 32 μg/mL, 8 μg/mL and 64 μg/mL, respectively. The most active agents againstStenotrophomonas maltophiliawere tigecycline and trimethoprimsulfamethoxazole and levofloxacin with MIC90sof 8 μg/mL, 8 μg/mL and 8 μg/mL, respectively. The most active agents againstAcinetobacter baumanniiwere amikacin, fluoroquinolones (eg, levofloxacin), meropenem, and tigecycline with MIC90sof 2 μg/mL or less, 1 μg/mL, 4 μg/mL and 2 μg/mL, respectively. CONCLUSIONS: The most active agents versus Gram-positive cocci from Canadian hospitals were vancomycin, linezolid, daptomycin, tigecycline, dalbavancin and telavancin. The most active agents versus Gram-negative bacilli from Canadian hospitals were amikacin, cefepime, ertapenem (notP aeruginosa), meropenem, piperacillintazobactam and tigecycline (notP aeruginosa). Colistin (polymyxin E) was very active againstP aeruginosaandA baumannii.


2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Andrew Walkty ◽  
James A. Karlowsky ◽  
Melanie R. Baxter ◽  
Heather J. Adam ◽  
George G. Zhanel

ABSTRACTThe Clinical and Laboratory Standards Institute (CLSI) broth microdilution method was used to evaluate thein vitroactivities of plazomicin and comparator antimicrobial agents against 7,712 Gram-negative and 4,481 Gram-positive bacterial pathogens obtained from 2013 to 2017 from patients in Canadian hospitals as part of the CANWARD Surveillance Study. Plazomicin demonstrated potentin vitroactivity againstEnterobacteriaceae(MIC90≤ 1 µg/ml for all species tested exceptProteus mirabilisandMorganella morganii), including aminoglycoside-nonsusceptible, extended-spectrum β-lactamase (ESBL)-positive, and multidrug-resistant (MDR) isolates. Plazomicin was equally active against methicillin-susceptible and methicillin-resistant isolates ofStaphylococcus aureus.


2021 ◽  
Vol 22 (6) ◽  
Author(s):  
Widodo Suwito ◽  
WIDAGDO SRI NUGROHO ◽  
AGNESIA ENDANG TRI HASTUTI WAHYUNI ◽  
BAMBANG SUMIARTO

Abstract. Suwito W, Nugroho WS, Wahyuni AETH, Sumiarto B. 2021. Antimicrobial resistance in coagulase-negative staphylococci isolated from subclinical mastitis in Ettawa Crossbred goat (PE) in Yogyakarta, Indonesia. Biodiversitas 22: 3418-3422. Subclinical mastitis (SCM) in Ettawa Crossbred Goat (PE) is most frequently caused by staphylococci with a significant reduction in milk yield. The aim of this study is to determine antimicrobial resistance patterns of coagulase-negative staphylococci (CoNS) from PE goat SCM. A total of 36 CoNS isolates originating from PE goat SCM were collected in semisolid tube use in this study. All CoNS isolates were further examined for antimicrobial susceptibility testing by the Kirby-Bauer disc diffusion method. Antibiotic susceptibility of CoNS isolated samples according to Clinical Laboratory Standards Institute (CLSI). The CoNS isolates showed the highest resistance rate against sulfamethoxazole (65%), ampicillin (55.56%), penicillin (45%), cefoxitin (33.33%), erythromycin (25%), oxytetracycline (20%), tetracycline (15%), gentamicin and neomycin (11.11%), while oxacillin was sensitive. The highest of multiple antimicrobials resistance observed 15% in ampicillin, penicillin and tetracycline, then 5-10% in ampicillin, penicillin, erythromycin, tetracycline and oxytetracycline. The majority of CoNS in this study were resistant to sulfamethoxazole and then, followed by ampicillin, penicillin, cefoxitin, erythromycin, oxytetracycline, tetracycline, gentamicin and neomycin. In addition, most isolates were penicillin-resistant and multidrug-resistant (MDR).


2019 ◽  
Vol 21 (4) ◽  
pp. 317-323
Author(s):  
Nataly V. Ivanchik ◽  
Marina V. Sukhorukova ◽  
Aida N. Chagaryan ◽  
Andrey V. Dekhnich ◽  
Roman S. Kozlov ◽  
...  

Objective. To evaluate antimicrobial resistance patterns of clinical Haemophilus influenzae isolates from different regions of Russia during 2014–2017. Materials and Methods. We included in the study 185 clinical H. influenzae isolates from 13 Russian cities. Susceptibility testing was performed by reference broth microdilution method (ISO 207761:2006). Susceptibility testing results were interpreted using EUCAST v. 10.0 breakpoints. Results. H. influenzae isolates were highly susceptible to all (96.8%-100%) β-lactams tested (amoxicillin/ clavulanate, cefixime, ceftaroline, ceftibuten, cefditoren, ertapenem) with the exception of ampicillin (15.1% isolates were resistant). Fluoroquinolones, – ciprofloxacin, levofloxacin, moxifloxacin were active against 95.7%, 94.6% and 97.9% of isolates, respectively. Chloramphenicol was active against 97.9% of isolates, tetracycline – against 98.4% of isolates. Activity of trimethoprim/sulfamethoxazole was low (69.2% of susceptible isolates). Conclusions. In general, we can state the favorable situation with the susceptibility of H. influenzae to antimicrobials in Russia. However, the increasing of resistance to aminopenicillins and emerging of quinolone-resistant strains could become a problem in the future. Study Results are deposited at on-line resource AMRmap (http://AMRmap.ru).


Author(s):  
Serap Süzük Yıldız ◽  
Can Hüseyin Hekimoğlu ◽  
Zekiye Bakkaloğlu ◽  
Emine Alp

AbstractThe selection of therapeutic agent to be used for the treatment of multidrug-resistant bacteria is a major concern. Polymyxin B use has been commenced in Turkey, although its clinical breakpoint is not listed in the EUCAST. This study aimed to determine the correlation between the MIC values of polymyxin B and colistin. A total of 505 isolates, including 122 isolates of Escherichia coli and 383 isolates of Klebsiella pneumoniae were included in the present study. All the isolates were assessed for colistin and polymyxin B using the broth microdilution method. The categorical agreement in the E. coli isolates was 98.4%, and the rate of very major error was 33.3%. The categorical agreement in the K. pneumoniae isolates was 99.5%, the rate of major error was 0.36%, and the rate of very major error was 0.98%. In the evaluation of the essential agreement, 1.6% error in E. coli and 2.3% error in K. pneumoniae were observed. It was concluded that polymyxin B should never be used in the treatment of the isolates reported as colistin-resistant, and if the MIC values are above 4 mg/L in E. coli and K. pneumoniae. Our results indicate importance of reporting both polymyxin B and colistin susceptibility results of clinical isolates.


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