Antibiotic Resistances and Molecular Characteristics of Clostridioides difficile in ICUs in a Teaching Hospital From Central South China

Clostridioides (C.) difficile is a major healthcare-associated pathogen inducing infectious diarrhea. Approximately 25–33% of patients with antibiotic-associated diarrhea (AAD) and 90% of patients with pseudomembranous enteritis are caused by C. difficile infection (CDI). Stool samples were collected from hospitalized adults with presumptive AAD in four nonneonatal intensive care units (ICUs). Diagnosis of CDI was based on both clinical symptoms and laboratory results. The stool specimens were transferred onto CDIF (C. difficile agar), and C. difficile was finally confirmed by the latex agglutination test. Toxin-producing genes tcdA (A), tcdB (B), and cdt (CDT) were detected by PCR, and all isolates were performed multilocus sequence typing analysis. The antibiotic susceptibility of C. difficile isolates was assessed by the agar dilution method. A total of 184 C. difficile were isolated from 857 specimens in our study, the isolation rate of C. difficile was 21.5% (184/857). The 184 C. difficile were isolated from 179 patients, among these 115 patients were toxin-positive, giving the incidence of CDI being 58.0/10,000 patient days in the four ICUs. Among these 115 toxin-positive C. difficile isolates, 100 (87.0%) isolates produced two toxins (A+B+CDT-), three (2.6%) isolates were A+B+ with binary toxin-producing (A+B+CDT+), and 12 (10.4%) isolates only produced one toxin (A-B+CDT-). A total of 27 sequencing types (STs) were obtained. The most prevalent was ST3 (34 isolates), followed by ST39 (27 isolates), ST54 (19 isolates), ST26 (16 isolates), ST35 (15 isolates), and ST2 (13 isolates). All the ST26 isolates were nontoxigenic. Meanwhile, five STs were newly discovered. Although multidrug resistance was present in ≥50% of these C. difficile isolates, all of them were susceptible to tigecycline, fidaxomicin, metronidazole, and vancomycin. In conclusion, C. difficile isolates producing two toxins (A+B+CDT-) were dominant in our hospital. The most prevalent was ST3, and all ST26 isolates were NTCD. Although multidrug resistance was present in ≥50% of the C. difficile isolates, metronidazole, tigecycline, fidaxomicin, and vancomycin were still effective treatments for CDI in our hospital.

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Prevalence, Antibiogram and Molecular Characterization of Comunity-Acquired Methicillin-Resistant Staphylococcus Aureus in AWKA, Anambra Nigeria

The Open Microbiology Journal ◽

10.2174/1874285801610010211 ◽

2016 ◽

Vol 10 (1) ◽

pp. 211-221 ◽

Cited By ~ 3

Author(s):

Blessing Ike ◽

Malachy C. Ugwu ◽

Moses N. Ikegbunam ◽

David Nwobodo ◽

Chika Ejikeugwu ◽

...

Keyword(s):

Antibiotic Resistance ◽

Binding Protein ◽

Meca Gene ◽

Latex Agglutination ◽

Diffusion Method ◽

Dilution Method ◽

Agar Dilution Method ◽

Penicillin Binding Protein ◽

Carriage Rate ◽

Molecular Features

Objectives:This study evaluated the prevalence, antibiogram and molecular features of CA-MRSA in Awka, Nigeria.Methods:Confirmation of MRSA was done by testing resistance to oxacillin (1µg), cloxacillin (5µg) and cefoxitin(30µg) on sterile Mueller Hinton agar supplemented with 4% sodium chloride. The MRSA strains were subjected to antimicrobial susceptibility testing using Kirby-Bauer disc diffusion method. Minimum inhibitory concentration was determined using agar dilution method. Penicillin binding protein 2a was detected through rapid latex agglutination assay while mecA gene was detected by polymerase chain reaction. A total of 142S. aureusisolates were obtained from 261 samples sourced from Staff, students and fomites of the Faculty of Pharmaceutical SciencesResult:The overall prevalence of MRSA was 22.6%. The carriage rate was higher in females (56.5%) than male (43.5%) and was highest in individuals of 20-30 years of age (57.65%). The MIC of the oxacillin sodium salt ranged from 4-32 μg/ml. The multi-antibiotic resistance indices show that 53.4% had Multiple Antibiotic Resistance Indexing (MARI) higher than 0.2. Penicillin binding protein 2a was detected in 8.4% of MRSA isolates, all from nasal carriage while mecA gene was detected in 5 of isolates.Conclusion:This study showed a very high prevalence of MRSA carriage among studied subjects.

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Characterization of Clinical Isolates ofEnterococciwith Special Reference to Glycopeptide Susceptibility at a Tertiary Care Center of Eastern Nepal

International Journal of Microbiology ◽

10.1155/2019/7936156 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Aasish Karna ◽

Ratna Baral ◽

Basudha Khanal

Keyword(s):

Multidrug Resistance ◽

Minimum Inhibitory Concentration ◽

Antimicrobial Susceptibility ◽

Inhibitory Concentration ◽

Tertiary Care ◽

Dilution Method ◽

Agar Dilution Method ◽

Disc Diffusion ◽

Diffusion Technique ◽

Agar Dilution

Background. Enterococci, once considered as a harmless commensal of intestine, have now emerged as medically important pathogens and are associated with both community-acquired and nosocomial infections. They bear the potential to exhibit resistance against all commonly used antibiotics either by inherent or acquired mechanism, posing a therapeutic challenge.Objectives. This study aimed to characterize enterococci up to the species level and study their antibiogram with special regard to vancomycin.Methods. A descriptive cross-sectional study was conducted in the Department of Microbiology, B.P. Koirala Institute of Health Sciences, Dharan, Nepal, from February to May 2017. A total of 91 enterococcal isolates recovered from clinical specimens were investigated in this study. Their identification and speciation were done according to standard microbiological guidelines. Kirby–Bauer disc diffusion technique was used to study antimicrobial susceptibility pattern, whereas minimum inhibitory concentration of vancomycin was determined by the agar dilution method, with reference to Clinical and Laboratory Standards Institute guidelines.Results. Seven different species of enterococci were isolated,E. faecalisandE. faeciumaccounting about 45% each. The other species encountered wereE.avium,E.cecorum,E.dispar,E.durans, andE.raffinosus. Highest proportion of antimicrobial susceptibility was recorded for linezolid (97.8%), followed by teicoplanin (95.6%) and high-level gentamicin (81.3%). Sensitivity to vancomycin was seen in 79.1% isolates. Likewise, 82.1% of urinary strains were susceptible to nitrofurantoin. A total of 4 disparities were observed between the disc diffusion technique and agar dilution method in determining vancomycin resistance. Multidrug resistance was observed in 31.9% isolates. The overall prevalence of vancomycin-resistant enterococci based on the standard minimum inhibitory concentration method was 25.3%.Conclusions.Enterococcus faecalisandE. faeciumwere the predominant species in causing enterococcal infections. The alarming rise in prevalence of vancomycin and multidrug resistance strains warrants immediate, adequate, and efficient surveillance program to prevent and control its spread.

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Antimicrobial susceptibility of Clostridioides difficile isolated from diarrhoeal stool specimens of Canadian patients: summary of results from the Canadian Clostridioides difficile (CAN-DIFF) surveillance study from 2013 to 2017

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkaa118 ◽

2020 ◽

Vol 75 (7) ◽

pp. 1824-1832

Author(s):

James A Karlowsky ◽

Heather J Adam ◽

Melanie R Baxter ◽

Christopher W Dutka ◽

Kim A Nichol ◽

...

Keyword(s):

Antimicrobial Susceptibility ◽

Susceptibility Testing ◽

Surveillance Study ◽

Dilution Method ◽

Agar Dilution Method ◽

In Vitro Susceptibility ◽

Ribotype 027 ◽

Clostridioides Difficile ◽

Vancomycin Mics ◽

Stool Specimens

Abstract Objectives To summarize data generated by the Canadian Clostridioides difficile (CAN-DIFF) surveillance study from 2013 to 2017. Methods Isolates of C. difficile (n = 2158) were cultured from toxin-positive diarrhoeal stool specimens submitted by eight hospital laboratories to a coordinating laboratory. Antimicrobial susceptibility testing was performed according to the CLSI agar dilution method (M11, 2018). Isolate ribotypes were determined using an international, standardized, high-resolution capillary gel-based electrophoresis protocol. Results Of the 2158 isolates of C. difficile, 2133 (98.8%) had vancomycin MICs ≤2 mg/L [i.e. were vancomycin susceptible (EUCAST breakpoint tables, v 9.0, 2019) or WT (CLSI M100, 29th edition, 2019)]. Fidaxomicin MICs were lower than those of all other agents tested (MIC90, 0.5 mg/L); however, one isolate with a fidaxomicin MIC of >8 mg/L was identified. Metronidazole MICs ranged from 0.12 to 4 mg/L; all isolates were metronidazole susceptible by the CLSI breakpoint (≤8 mg/L) compared with 96.8% susceptible by the EUCAST breakpoint (≤2 mg/L). In total, 182 different ribotypes were identified from 2013 to 2017. The most common ribotypes identified were 027 (19.3% of isolates) and 106 (8.2%). Ribotype 027 isolates were frequently moxifloxacin resistant (87.3% of isolates) and MDR (48.6%), associated with vancomycin (10/25, 40.0%) and metronidazole (58/69, 84.1%) resistance and from patients aged ≥80 years. The prevalence of ribotype 027 decreased significantly (P < 0.0001) from 2013 (27.5%) to 2017 (9.0%) and was replaced by increases in ribotype 106 (P = 0.0003) and multiple less common ribotypes. Conclusions Periodic surveillance is required to monitor clinical isolates of C. difficile for changes to in vitro susceptibility testing profiles and ribotype evolution.

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Department of Microbiology, Bangladesh Agricultural University, Mymensingh

Bangladesh Journal of Medical Microbiology ◽

10.3329/bjmm.v2i2.28839 ◽

2016 ◽

Vol 2 (2) ◽

pp. 3-6

Author(s):

Nahida Akther Zahan ◽

Md. Akram Hossain ◽

AKM Shamsuzzaman ◽

AKM Musa ◽

Md. Chand Mahamud ◽

...

Keyword(s):

Clinical Laboratory ◽

Methicillin Resistance ◽

Meca Gene ◽

Toxin Production ◽

Latex Agglutination ◽

Diffusion Method ◽

National Committee ◽

Dilution Method ◽

Agar Dilution Method ◽

Disk Diffusion Method

The study was done to detect different exotoxins among the strains of Staphylococcus aureus isolated in the department of Microbiology, Mymensingh Medical College in collaboration with the Department of Medicine under the Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh between the periods from July, 2006 to June, 2007. A total of 40 S. aureus isolates investigated in this study were identified by standard microbiological techniques. Antimicrobial susceptibility of the isolates to Oxacillin was carried out by disk diffusion method as per recommendation of the National Committee for Clinical Laboratory Standards. Any isolate showing resistance to Oxacillin was tested again by agar dilution method to determine minimum inhibitory concentration (MIC) of Methicillin. All strains were also tested for mecA gene by Polymerase Chain Reaction (PCR) for confirmation of Methicillin resistance. Enterotoxin (A-D) and Toxic Shock Syndrome Toxin-1 (TSST-1) were detected by Reverse Passive Latex Agglutination (RPLA) test. Out of 40 S. aureus isolates, 7 (17.5%) Methicillin Resistant S. aureus (MRSA), 1 (2.5%) Methicillin Sensitive S. aureus (MSSA) produced Staphylococcal Enterotoxin A (SE-A) and 1 MRSA isolate was positive for TSST-1. In case of combined toxin production among the S. aureus isolates, 2 (5%) MSSA were found to produce SE-A and SE-B, 2 (5%) MSSA produced SE-C and SE-D, and 1 (2.5%) MRSA, 1 (2.5%) MSSA produced SE-C and TSST-1.Bangladesh J Med Microbiol 2008; 02 (02): 3-6

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The Prevalence of Multidrug Resistance of Helicobacter pylori and Its Impact on Eradication in Korea from 2017 to 2019: A Single-Center Study

Antibiotics ◽

10.3390/antibiotics9100646 ◽

2020 ◽

Vol 9 (10) ◽

pp. 646

Author(s):

Jae Yong Park ◽

Tae-Seop Shin ◽

Ji Hyun Kim ◽

Hong Jip Yoon ◽

Beom Jin Kim ◽

...

Keyword(s):

Helicobacter Pylori ◽

Multidrug Resistance ◽

Eradication Therapy ◽

University Hospital ◽

Gastric Body ◽

Dilution Method ◽

Agar Dilution Method ◽

Line Treatment ◽

First Line ◽

H Pylori

Antimicrobial resistance is one of the major factors determining the efficacy of Helicobacter pylori eradication therapy. This study aimed to estimate the recent prevalence of multidrug resistance of H. pylori and its impact on eradication in Korea. A total of 174 patients were prospectively enrolled at Chung-Ang University Hospital from 2017 to 2019. H. pylori strains were isolated from the gastric body and antrum. The minimum inhibitory concentrations of antibiotics were determined by the serial twofold agar dilution method. Eradication results were reviewed and analyzed in connection with antibiotic resistance. The prevalence of H. pylori infection was 51.7% (90/174). The culture success rate was 77.8% (70/90). The resistance rates for clarithromycin, metronidazole, amoxicillin, tetracycline, levofloxacin, and moxifloxacin were 28.6% (20/70), 27.1% (19/70), 20.0% (14/70), 18.6% (13/70), 42.9% (30/70), and 42.9% (30/70), respectively. The multidrug resistance (resistance to two or more classes of antimicrobials) rate was 42.9% (30/70). Dual resistance to clarithromycin and metronidazole was confirmed in 8.6% (6/70). Eradication with a first-line treatment was successful in 75% (36/48), and those who received second-line treatment all achieved successful eradication. The rate of multidrug resistance is increasing, and standard triple therapy (STT) is no longer an acceptable first-line option for H. pylori eradication in Korea.

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Prevalence of Virulence Factors and Drug Resistance in Clinical Isolates of Enterococci: A Study from North India

Journal of Pathogens ◽

10.1155/2015/692612 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 12

Author(s):

Tuhina Banerjee ◽

Shampa Anupurba

Keyword(s):

Drug Resistance ◽

Multidrug Resistance ◽

Virulence Factors ◽

Virulence Genes ◽

Vancomycin Resistance ◽

North India ◽

Dilution Method ◽

Agar Dilution Method ◽

Virulence Traits ◽

High Level

Along with emergence of multidrug resistance, presence of several virulence factors in enterococci is an emerging concept. This study was undertaken to determine the prevalence of various virulence factors phenotypically and genotypically in enterococci and study their association with multidrug resistance. A total of 310 enterococcal isolates were studied, comprising 155E. faeciumand 155E. faecalis. Antimicrobial susceptibility testing was done by disc diffusion and agar dilution method. Hemolysin, gelatinase, biofilm production, and haemagglutination were detected phenotypically and presence of virulence genes, namely,asa1, gelE, cylA, esp, andhyl, was detected by multiplex PCR. Of the total, 47.41% isolates were high level gentamicin resistant (HLGRE) and 7.09% were vancomycin resistant (VRE). All the virulence traits studied were found in varying proportions, with majority inE. faecalis(p>0.05). Strong biofilm producers possessed eitherasa1orgelEgene.gelEsilent gene was detected in 41.37% (12/29). However, increase in resistance was associated with significant decrease in expression or acquisition of virulence genes. Further, acquisition of vancomycin resistance was the significant factor responsible for the loss of virulence traits. Though it is presumed that increased drug resistance correlates with increased virulence, acquisition of vancomycin resistance might be responsible for reduced expression of virulence traits to meet the “biological cost” relating to VRE.

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Emergence and rising of ceftazidime-avibactam resistant KPC-producing Pseudomonas aeruginosa in China: a molecular epidemiology study

10.1101/2020.12.15.20248268 ◽

2020 ◽

Author(s):

Yiwei Zhu ◽

Jie Chen ◽

Han Shen ◽

Zhongju Chen ◽

Qiwen Yang ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Gene Copy Number ◽

Carbapenem Resistance ◽

Multidrug Resistant ◽

Gene Copy ◽

Molecular Characteristics ◽

Dilution Method ◽

Agar Dilution Method ◽

Klebsiella Pneumoniae Carbapenemase ◽

Broth Microdilution Method

Background: Infections by Carbapenem-resistant Pseudomonas aeruginosa (CRPA) are difficult to treat and novel antibiotics are desperately needed. Till today, ceftazidime-avibactam (CAZ-AVI) has been used to treat infections caused by multidrug resistant (MDR) Gram-negative bacteria, including Klebsiella pneumoniae carbapenemase (KPC)-producing organisms. Although cases of KPC-producing P. aeruginosa (KPC-PA) have been reported sporadically, data about KPC-PA susceptibility to CAZ-AVI and its molecular characteristics are limited. Methods: CRPA were collected from seven hospitals in China from 2017 to 2018. PCR was deployed to screen for the blaKPC gene. Antimicrobial susceptibility of KPC-PA was determined by broth microdilution method or agar dilution method. We combined Illumina sequencing and Nanopore long-read sequencing to elucidate the genomic characteristics of KPC-PA strains. Results: KPC-PA strains were found in six out of seven hospitals. 151/374 (40.4%) CRPA clinical isolates harbored the blaKPC-2 gene. Among KPC-PA, ST463 (107/151) was predominant, followed by ST485 (14/151) and ST1212 (12/151). Approximately half of all KPC-PA (50.3%) were susceptible to CAZ-AVI. We found that the blaKPC-2 gene copy number correlated with CAZ-AVI MIC. In more than 90% (136/151) of the strains, we found plasmids that belonged to two types carrying blaKPC-2 gene. The Type 1 plasmid, predominant in East China, was identified in 118 strains and the Type 2 plasmid, belonged to a megaplasmid family spreading globally, was identified in 19 strains. In addition, we identified IS26-ΔTn6296 and IS6100-ΔTn6296-Tn1403 as two mobile genetic elements that mediated blaKPC-2 gene transmission. Conclusion: Our results suggest that the blaKPC-2 gene is becoming a remarkable mediator of carbapenem resistance in P. aeruginosa in China. The emergence and spread of such KPC-PA strains poses a threat on clinical therapy as CAZ-AVI becomes inefficient. It would be beneficial to screen for the blaKPC gene in CRPA strains for antimicrobial surveillance.

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Antimicrobial Susceptibility of Invasive Streptococcus pneumoniae Isolates in Portugal over an 11-Year Period

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00198-06 ◽

2006 ◽

Vol 50 (6) ◽

pp. 2098-2105 ◽

Cited By ~ 16

Author(s):

Ricardo Dias ◽

Deolinda Louro ◽

Manuela Caniça

Keyword(s):

Multidrug Resistance ◽

Streptococcus Pneumoniae ◽

Antimicrobial Susceptibility ◽

Antimicrobial Agents ◽

Invasive Disease ◽

Dilution Method ◽

Agar Dilution Method ◽

National Surveillance ◽

Agar Dilution

ABSTRACT This national surveillance study presents the in vitro activities of the main antimicrobial agents against 1,331 S. pneumoniae isolates as tested by an agar dilution method according to the guidelines of the Clinical and Laboratory Standards Institute (formerly NCCLS). The strains were isolated in several regions of Portugal from cases of invasive disease over an 11-year period (1994 to 2004). This study shows that the percentage of penicillin-nonsusceptible strains increased from 12% in 1994 to 28.5% in 2000. Then the rate declined to 17.7% in 2003 but increased again to 23.2% in 2004. Nevertheless, the rate of highly resistant isolates declined consistently, to 0.9% in 2001 to 2004. Ceftriaxone- and cefotaxime-nonsusceptible isolates became less frequent, from 4% and 8%, respectively, in 1994 to ≤1% in 2004. The macrolide-lincosamide-streptogramin B phenotype was the predominant macrolide phenotype found. The increase in the percentage of isolates that were only nonsusceptible to erythromycin (3.7% in 1994 to 1998 to 9.1% in 2002 to 2004) was similar to that for isolates with coresistance to penicillin and erythromycin (3.3% in 1994 to 1998 to 9.1% in 2002 to 2004). The nonsusceptibility to ciprofloxacin increased during recent years, from 0.5% in 2002 to 3.5% in 2004. Multidrug resistance also increased in recent years: from 7.9% in 2002 to 15.6% in 2004. The increasing use of macrolides could be causing the increase in penicillin and multidrug resistance, due to the coresistance to macrolides. The use of penicillin to treat empirical invasive pneumococci infections may need to be reconsidered.

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Pathogenic characteristics of Staphylococcus aureus isolates from arthroplasty infections

The International Journal of Artificial Organs ◽

10.1177/0391398820948877 ◽

2020 ◽

pp. 039139882094887

Author(s):

Peng Chen ◽

Fengjun Sun ◽

Wei Feng ◽

Hai Hong ◽

Bo Li ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Biofilm Formation ◽

Tertiary Care ◽

Pcr Amplification ◽

Bacterial Biofilm ◽

Molecular Characteristics ◽

Dilution Method ◽

Agar Dilution Method ◽

Great Ability ◽

Adhesion Ability

Background: Staphylococcus aureus has a great ability to form biofilms on implant-related biomaterials. This study aimed to investigate the resistance, biofilm and molecular characteristics of S. aureus strains isolated from patients with postoperative infections after arthroplasty in two Chinese tertiary care hospitals during 2017 to 2018. Methods: Antimicrobial susceptibility was determined by the agar dilution method. Bacterial biofilm formation was determined by crystal violet staining. The genes related to biofilm formation and molecular typing were analyzed by PCR amplification. Results: A total of 33 isolates were collected, 21 of which were from Henan. The strains were completely sensitive to vancomycin, linezolid, and nitrofurantoin. All the isolates had adhesion ability and could produce biofilms. Of the isolates, 75.0% from Chongqing and 85.7% from Henan had stronger biofilm formation abilities. The strains from Henan had slightly higher resistance, adhesion and biofilm-forming abilities than those from Chongqing. The strains in both hospitals carried at least two genes related to biofilm formation, and the ica and fnb genes were the most frequently detected genes. Three SCC mec types and seven sequence types (STs) were found in Henan, and two SCC mec types and six STs were found in Chongqing. ST239-SCC mec III was the main epidemic clone in the two hospitals. Conclusion: The resistance phenotype and molecular characteristics of S. aureus strains varied in different hospitals. The results reflect the potential risks of S. aureus infection in postoperative arthroplasty patients. Our study provides a powerful basis for the clinical treatment, infection control and monitoring of outbreaks of epidemic strains.

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Evaluation of the antimicrobial activity of ridinilazole and six comparators against Chinese, Japanese and South Korean strains ofClostridioides difficile

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkaa522 ◽

2020 ◽

Author(s):

Deirdre A Collins ◽

Yuan Wu ◽

Kazuhiro Tateda ◽

Hee-Jung Kim ◽

Richard J Vickers ◽

...

Keyword(s):

Antimicrobial Activity ◽

South Korea ◽

Antimicrobial Agents ◽

Specific Activity ◽

Fluoroquinolone Resistance ◽

Dilution Method ◽

Agar Dilution Method ◽

Clostridioides Difficile ◽

Ongoing Surveillance ◽

And Control

Abstract Background Clostridioides difficile is the most common cause of antimicrobial-associated diarrhoea in high-income countries. Fluoroquinolone resistance enabled the emergence and intercontinental spread of the epidemic ribotype (RT) 027 strain ofC. difficile in the early 2000s. Despite frequent inappropriate antimicrobial use in Asia, RT 027 is rarely isolated in the region, but the often fluoroquinolone- and clindamycin-resistant RT 017 strain predominates. Objectives This study evaluated the antimicrobial activity of ridinilazole, a novel antimicrobial agent with highly specific activity forC. difficile, against clinical strains ofC. difficile from Asia. Methods C. difficile strains from Japan (n = 64), South Korea (n = 32) and China (n = 44) were tested by the agar dilution method for susceptibility to ridinilazole, metronidazole, vancomycin, clindamycin, moxifloxacin, rifaximin and fidaxomicin. Results All strains were susceptible to ridinilazole, with low MICs (0.03–0.25 mg/L). Several strains showed multiresistance profiles, particularly RT 017 (100% clindamycin resistant, 91.3% moxifloxacin resistant, 82.6% rifaximin resistant) and RT 369 (94.4% clindamycin resistant, 100% moxifloxacin resistant). Rifaximin resistance was absent in all strains from Japan. Multiresistance to clindamycin, moxifloxacin and rifaximin was found in 19 RT 017 strains (from China and South Korea), 2 RT 001 strains (South Korea) and 1 RT 046 strain (South Korea). Conclusions Ridinilazole showed potent activity against a range of AsianC. difficile strains, which otherwise frequently displayed resistance to several comparator antimicrobial agents. Ongoing surveillance of antimicrobial resistance profiles is required to monitor and control the spread of resistant strains.

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