European Committee on Antimicrobial Susceptibility Testing-Recommended Rapid Antimicrobial Susceptibility Testing of Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus From Positive Blood Culture Bottles

Park Jong-Min,Kwon Mijung,Hong Ki Ho,Lee Hyukmin,용동은 대한진단검사의학회 2023 Annals of Laboratory Medicine Vol.43 No.5

Background: Early diagnosis and treatment are important for a good prognosis of bloodstream infections. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommends rapid antimicrobial susceptibility testing (RAST) based on the disk diffusion methodology for 4, 6, and 8 hours of incubation. We evaluated EUCAST-RAST of Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus from positive blood culture bottles. Methods: Twenty strains of E. coli, K. pneumoniae, and S. aureus were tested using EUCAST-RAST. Ten antimicrobial agents against E. coli and K. pneumoniae and four agents against S. aureus were tested. The diameter of the inhibition zone (mm) was compared with the minimal inhibitory concentration (μg/mL) obtained using the Sensititre AST system (TREK Diagnostic Systems, East Grinstead, UK). Results: For E. coli, the percentage of total categorical agreement (CA) was 69.5% at 4 hours, and 87% at 8 hours. For K. pneumoniae, the total CA was 89% at 4 hours, and 95.5% at 6 hours. For S. aureus, the total CA was 100% after 4 hours. Discrepancies were observed mainly for E. coli with β-lactam antimicrobial agents, and the numbers of errors decreased over time. Conclusions: EUCAST-RAST for K. pneumoniae and S. aureus met the United States Food and Drug Administration criteria at 6 and 4 hours, respectively, whereas that for E. coli did not meet the criteria for up to 8 hours. RAST can shorten the turn-around testing time by more than one day; therefore, if applied accurately according to laboratory conditions, antimicrobial agent results can be reported faster.

국내 다제내성 및 광범위내성결핵의 최근 현황

김선영 ( Sun Young Kim ),김희진 ( Hee Jin Kim ),김창기 ( Chang Ki Kim ),윤혜령 ( Hye Ryung Yoon ),배혜경 ( Hye Gyung Bae ),이선화 ( Sun Hwa Lee ),성낙문 ( Nack Moon Sung ),김대연 ( Dae Yeon Kim ),이강영 ( Gang Young Lee ),조영수 ( 대한결핵 및 호흡기학회 2010 Tuberculosis and Respiratory Diseases Vol.68 No.3

Background: The increasing incidence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) has become a serious worldwide problem. However, there is insufficient data regarding the current status of MDR-TB and XDR-TB in Korea. This study examined the recent status of MDR- and XDR-TB using the data from 7 laboratories, in which almost all drug susceptibility tests (DST) for Mycobacterium tuberculosis were performed. Methods: The patients` identification data and DST results were collected from all 7 laboratories from 2001 to 2006 and the number of patients with MDR-TB and XDR-TB were calculated. Results: The number of DSTs was 140,638 for 6 years with an increasing incidence each year (p<0.001). The number of DST with MDR results was 18,510 and personal identifying information was obtained in 16,640 (89.9%) tests. The number of MDR-TB patients from 2001 to 2006 was 2,329, 2,496, 2,374, 2,300, 2,354, and 2,178, respectively, when counting the duplications in a year as one patient. The number of MDR-TB patients when counting the duplications in 6 years as one patient was 2,281, 1,977, 1,620, 1,446, 1,512, and 1,373, respectively. When the same method was adopted, the number of XDR-TB patients was 191, 238, 282, 260, 272, and 264, respectively, and 189, 150, 130, 90, 122, and 110 patients, respectively. Conclusion: Despite the national efforts to control TB, there are still a large number of MDR- and XDR-TB patients in Korea.

Results of Urine Culture and Antimicrobial Sensitivity Tests According to the Voiding Method Over 10 Years in Patients with Spinal Cord Injury

류경호,김윤범,양승옥,이정기,정태영 대한비뇨의학회 2011 Investigative and Clinical Urology Vol.52 No.5

Purpose: We studied the results of urine cultures and antimicrobial sensitivity tests according to the voiding method used by spinal cord injury (SCI) patients over a recent 10-year period. Materials and Methods: We retrospectively analyzed 1,236 urine samples and their antimicrobial sensitivity tests for 112 patients who had used only one voiding method between January 2000 and December 2009. The voiding methods were classified into four groups: clean intermittent catheterization (CIC), suprapubic catheterization, urethral Foley catheter, and spontaneous voiding. Results: Of the 1,236 urine samples, 925 (74.8%) were positive and 279 (30.2%) had more than one bacteria. The CIC group showed the lowest rate of bacteriuria, colony counts, and polymicrobial infection (p<0.001). Causative organisms were mostly Gram-negative bacteria (84%), including Pseudomonas aeruginosa (22.9%), Escherichia coli (21.1%), Klebsiella species (6.7%), and Citrobacter species (6.3%). The rate of Gram-positive bacterial infection was 13.6%, and major pathogenic organisms were Streptococcus species (8.6%) and Staphylococcus species (2.6%). Major pathogenic organisms and the results of antimicrobial sensitivity tests differed according to the voiding method. Conclusions: Although the patient's condition and preferences are important when choosing the method of bladder management, CIC is the best voiding method for reducing urinary tract infections in SCI patients. When immediate use of antibiotics is needed for treatment of urinary tract infections, an appropriate antibiotic can be chosen according to the voiding method on the basis of our study and can be administered before the results of an antimicrobial sensitivity test are available.

The Role of Wound Swab Microbial Cultures and Antibiotic Sensitivity Results in the Management of Sacrococcygeal Pilonidal Abscess

Chao Cheng,Jiun Miin Lai,Krinalkumar Mori 대한외상중환자외과학회 2020 Journal of Acute Care Surgery Vol.10 No.1

Purpose: Current practice for patients who present to hospitals with acute sacrococcygeal pilonidal abscess is operative management. Wound swabs are routinely taken peri-operatively and antibiotics are initiated empirically pending culture and sensitivity results. The aim of our study was to evaluate whether the results of wound swabs change post-operative antibiotic therapy for these patients, and to identify the common microorganisms. Methods: This was a retrospective analysis which included patients who presented to the Northern Hospital, Victoria, with acute sacrococcygeal pilonidal abscess between 1st January 2013 to 30th June 2016. Data was collected using hospital electronic medical records. Patients who had wound swabs taken were identified and their post-operative management analyzed. Results: There were 297 presentations identified within the study period, of which, 224 cases (224/297, 75.4%) had wound swabs taken, out of which 130 (130/297, 43.8%) cases were followed up in outpatient clinic and 1 case (1/130, 0.8%) had a subsequent change in antibiotics based on the wound swab result. Common microorganisms grown were mixed anaerobes (138/224, 61.6%) and skin flora (45/224, 20.1%). Conclusion: Wound swabs could be omitted during peri-operative care for patients with acute sacrococcygeal pilonidal abscess. The because the results of wound swabs did not change the management of these patients. Additionally, omitting wound swabs could save money for the health care. Pre-operative antibiotic therapy should have anaerobic coverage as it is the most common type of micro-organism cultured from pilonidal abscesses.

Enterobacteriaceae에 대한 β-Lactam제 감수성시험 기준 및 Extended-Spectrum β-Lactamase와 Carbapenemase 검출을 위한 전략

박연준,송원근 대한임상미생물학회 2013 Annals of clinical microbiology Vol.16 No.3

The Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) have recently revised the susceptibility interpretive criteria of oxyimino-β-lactams and carbapenems for Enterobacteriaceae. According to the new criteria, susceptibility testing results are sufficient to detect extended-spectrum β-lactamases (ESBLs) and carbapenemases; it is not necessary to perform ESBL or carbapenemase detection tests for therapeutic purposes. Thus, it has been recommended that these related tests be performed only for infection control. These changes in the susceptibility guidelines are supported by some clinical cases and the results of pharmacodynamic and animal studies. However, differences still exist between the breakpoints established by the CLSI and EUCAST with regard to some oxyimino-β-lactam and carbapenem antibiotics, in particular, the breakpoints for ceftazidime and cefepime established by the CLSI are higher than those established by the EUCAST. Also, similar numbers of successful and unsuccessful cases have been reported regarding the use of cephalosporins or carbapenems in treating infections caused by low-minimal inhibitory concentration (MIC) ESBL-producers or low-MIC carbapenemase-producers. Finally, routine susceptibility test methods are not as accurate as research-purpose test methods, showing differences in MICs ranging approximately from 1 to 8 μg/mL. In conclusion, it is strategically prudent to continue to perform ESBL and carbapenemase detection tests and to avoid the use of the corresponding antimicrobial agents for the treatment of ESBL- or carbapenemase-producing bacterial infections.

2013년 국내 분리 임균의 항균제 내성 현황과 분자역학적 특성

김효진,서영희,김완희,이양순,이혁민,이경원,정윤섭 대한임상미생물학회 2013 Annals of clinical microbiology Vol.16 No.4

Background: Antimicrobial resistance of Neisseria gonorrhoeae has become a serious problem worldwide,and ceftriaxone non-susceptible isolates have been recently reported from Japan and Europe. In this study, we evaluated the antimicrobial susceptibilities and molecular epidemiological characteristics of isolates from Korea in 2013. Methods: Sixty strains of N. gonorrhoeae were collected from Korean patients and prostitutes. Antimicrobial susceptibility was tested by the agar dilution and disk diffusion methods. N. gonorrhoeae multi-antigen sequence typing (NG-MAST) was performed in order to determine the molecular epidemiologic relatedness. Results: All of isolates were non-susceptible to penicillin G and tetracycline, and the rate of ciprofloxacinresistant isolates was 95% in 2013. The MICs of ceftriaxone were within the susceptible range for all isolates,but one isolate non-susceptible to cefixime (MIC=0.5 μg/mL) was encountered. The isolates with decreased susceptibility (MIC≤0.12 μg/mL) to cefixime or ceftriaxone accounted for 10% and 14% of the isolates tested, respectively. In NG-MAST analysis,40 different STs were encountered among the 59isolates. Isolates that belonged to tbpB110 showed higher cefixime and ceftriaxone MICs (0.12-0.5 μg/mL) as well as cefixime resistance. Conclusion: Most of the N. gonorrhoeae isolates showed susceptibility to spectinomycin and cephalosporins. Due to the emergence of isolates that are non-susceptible to cefixime and the prevalence of isolates with the tbpB110 allele belonging to ST1407, which cause cefixime and ceftriaxone treatment failure in successful global clones of N. gonorrhoeae, a continuous nationwide antimicrobial surveillance program is required to monitor the emergence of cephalosporin resistance in N. gonorrhoeae.

급성담관염의 원인균주와 항생제감수성의 시간흐름에 따른 변화

권정석 ( Jeong Seok Kwon ),한지민 ( Ji Min Han ),김태원 ( Tae Won Kim ),오지혜 ( Ji Hye Oh ),권현희 ( Hyun Hee Kwon ),정진태 ( Jin Tae Jung ),권중구 ( Joong Goo Kwon ),김은영 ( Eun Young Kim ),김호각 ( Ho Gak Kim ) 대한소화기학회 2014 대한소화기학회지 Vol.63 No.5

Background/Aims: We evaluated changes of causative pathogen in acute cholangitis and their antimicrobial susceptibility over six years and differences between community-acquired and hospital-acquired acute cholangitis at our institution. Methods: Medical records of 1,596 patients with acute cholangitis and biliary drainage between August 2006 and August 2012 were reviewed retrospectively. Cases were divided according to time: period 1 (August 2006-December 2008, n=645, 40.4%), period 2 (January 2009-August 2012, n=951, 59.6%). Cases were divided according to community-acquired cholangitis (n=1,397, 87.5%) and hospital-acquired cholangitis (n=199, 12.5%). Causative pathogens and antimicrobial susceptibility were investigated in each group. Results: Causative pathogen was isolated from bile culture in 1,520 out of 1,596 cases (95.2%). The three most frequently isolated Gram-negative bacteria were extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (n=485, 30.4%), E. coli (n=237, 13.2%), and Citrobacter freundii (n=110, 6.9%). Between periods 1 and 2, prevalence of ESBL-producing E. coli and Klebsiella pneumoniae did not show significant change (36.7% vs. 32.1%, p=0.073; 6.6% vs. 6.2%, p=0.732). C. freundii showed a significant increase from period 1 to period 2 (1.7% vs. 13.2%, p=0.000). In both time periods, imipenem was the antimicrobial agent showing the highest rate of susceptibility (93.3% vs. 93.9%, p=0.783). Higher prevalence of ESBL-producing E. coli and C. freundii was observed in the hospital-acquired cholangitis group (52.1% vs. 31.2%, p=0.000; 15.9% vs. 7.3%, p=0.001). Conclusions: The most common causative pathogen of acute cholangitis was ESBL-producing E. coli. Prevalence of C. freundii increased over the time period. Imipenem should be reserved as an alternative for resistant pathogens.

A periodontitis-associated multispecies model of an oral biofilm

박종화,이재관,엄흥식,장범석,이시영 대한치주과학회 2014 Journal of Periodontal & Implant Science Vol.44 No.2

Purpose: While single-species biofilms have been studied extensively, we know notably littleregarding multispecies biofilms and their interactions. The purpose of this study was todevelop and evaluate an in vitro multispecies dental biofilm model that aimed to mimicthe environment of chronic periodontitis. Methods: Streptococcus gordonii KN1, Fusobacterium nucleatum ATCC23726, Aggregatibacteractinomycetemcomitans ATCC33384, and Porphyromonas gingivalis ATCC33277were used for this experiment. The biofilms were grown on 12-well plates with a roundglass slip (12 mm in diameter) with a supply of fresh medium. Four different single-speciesbiofilms and multispecies biofilms with the four bacterial strains listed above were prepared. The biofilms were examined with a confocal laser scanning microscope (CLSM) andscanning electron microscopy (SEM). The minimum inhibitory concentrations (MIC) for fourdifferent planktonic single-species and multispecies bacteria were determined. The MICs ofdoxycycline and chlorhexidine for four different single-species biofilms and a multispeciesbiofilm were also determined. Results: The CLSM and SEM examination revealed that the growth pattern of the multispeciesbiofilm was similar to those of single-species biofilms. However, the multispeciesbiofilm became thicker than the single-species biofilms, and networks between bacteriawere formed. The MICs of doxycycline and chlorhexidine were higher in the biofilm statethan in the planktonic bacteria. The MIC of doxycycline for the multispecies biofilm washigher than were those for the single-species biofilms of P. gingivalis, F. nucleatum, or A. actinomycetemcomitans. The MIC of chlorhexidine for the multispecies biofilm was higherthan were those for the single-species biofilms of P. gingivalis or F. nucleatum. Conclusions: To mimic the natural dental biofilm, a multispecies biofilm composed of fourbacterial species was grown. The 24-hour multispecies biofilm may be useful as a laboratorydental biofilm model system.

A periodontitis-associated multispecies model of an oral biofilm

Park, Jong Hwa,Lee, Jae-Kwan,Um, Heung-Sik,Chang, Beom-Seok,Lee, Si-Young Korean Academy of Periodontology 2014 Journal of Periodontal & Implant Science Vol.44 No.2

Purpose: While single-species biofilms have been studied extensively, we know notably little regarding multispecies biofilms and their interactions. The purpose of this study was to develop and evaluate an in vitro multispecies dental biofilm model that aimed to mimic the environment of chronic periodontitis. Methods: Streptococcus gordonii KN1, Fusobacterium nucleatum ATCC23726, Aggregatibacter actinomycetemcomitans ATCC33384, and Porphyromonas gingivalis ATCC33277 were used for this experiment. The biofilms were grown on 12-well plates with a round glass slip (12 mm in diameter) with a supply of fresh medium. Four different single-species biofilms and multispecies biofilms with the four bacterial strains listed above were prepared. The biofilms were examined with a confocal laser scanning microscope (CLSM) and scanning electron microscopy (SEM). The minimum inhibitory concentrations (MIC) for four different planktonic single-species and multispecies bacteria were determined. The MICs of doxycycline and chlorhexidine for four different single-species biofilms and a multispecies biofilm were also determined. Results: The CLSM and SEM examination revealed that the growth pattern of the multispecies biofilm was similar to those of single-species biofilms. However, the multispecies biofilm became thicker than the single-species biofilms, and networks between bacteria were formed. The MICs of doxycycline and chlorhexidine were higher in the biofilm state than in the planktonic bacteria. The MIC of doxycycline for the multispecies biofilm was higher than were those for the single-species biofilms of P. gingivalis, F. nucleatum, or A. actinomycetemcomitans. The MIC of chlorhexidine for the multispecies biofilm was higher than were those for the single-species biofilms of P. gingivalis or F. nucleatum. Conclusions: To mimic the natural dental biofilm, a multispecies biofilm composed of four bacterial species was grown. The 24-hour multispecies biofilm may be useful as a laboratory dental biofilm model system.

만성 중이염의 원인균과 항생제 감수성 분석

이현아,정재영,이하나,변하영,이승환,정재호 대한이비인후과학회 2023 대한이비인후과학회지 두경부외과학 Vol.66 No.12

Background and Objectives Chronic suppurative otitis media (CSOM) is one of the com-mon diseases in otolaryngology, and it is important to know the species of pathogens and anti-biotic susceptibility for its appropriate treatment. Methicillin-resistant Staphylococcus aureus(MRSA) infections have increased, and pathogenic bacteria and antibiotic resistance arechanging along with the inappropriate use and overuse of antibiotics. The aim of this study isto investigate the current bacterial profile and antimicrobial susceptibility patterns of CSOM. Subjects and Method We retrospectively investigated the bacteriological results of chronicotitis media with otorrhea in 272 outpatients who visited the department of otolaryngologyfrom January 2017 to July 2022. Results A total of 272 cases were included in the study, of which 245 (90.1%) were diag-nosed with CSOM without cholesteatoma and 27 (9.9%) were diagnosed with CSOM withcholesteatoma. Out of the total, 131 (48.2%) were male patients and 141 (51.8%) were femalepatients with a mean age of 60.0±14.93 years. Microbial growth was observed in 220 (80.9%)samples, but 17 (6.3%) samples showed no growth. Among the samples that showed growth, 184(67.6%) were monomicrobial and 71 (26.1%) were polymicrobial. A total of 277 isolates wereidentified. The most common pathogenic organism was MRSA (23.1%), followed by Pseudomo-nas aeruginosa (19.5%), methicillin-sensitive Staphylococcus aureus (19.1%), and coagulase-negative staphylococci (8.3%). MRSA was highly susceptible to vancomycin, linezolid, teico-planin (100%), sulfamethoxazole/trimethoprim, rifampin (over 96%). P. aer uginosa showedhighest susceptibility to ceftazidime (100%), then cefepime (96.3%) and imipenem & amikacin(92.6%), and was most resistant to ticarcillin/clavulanic acid (57.4%) and ciprofloxacin (64.8%). Conclusion Considering the high prevalence of MRSA and Ciprofloxacin-resistant P. aer u-ginosa, primary empirical antibiotics should be used with caution. Furthermore, periodic sur-veillance on the etiological agents of CSOM and its antimicrobial susceptibility is needed.