Evaluation of Diagnostics Colistin MIC-Strip Test for Colistin Susceptibility Testing

Günümüzde çoklu ilaç direncine sahip Gram negatif mikroorganizmaların neden olduğu enfeksiyonların tedavisinde kullanılacak antimikrobiyallerin kısıtlı olması nedeniyle kolistin gibi eski antibiyotikler sıklıkla tercih edilmeye başlanmıştır. Ancak, kolistinin katyonik yapısı nedeniyle rutin laboratuvarda sıklıkla kullanılan antibiyotik duyarlılık testlerinde (disk difüzyon, gradient test, otomatize sistemler) birtakım sorunlar yaşanmaktadır. Bu nedenle European Committee on Antimicrobial SusceptibilityTesting (EUCAST) ve Clinical and Laboratory Standards Institute (CLSI) tarafından kolistin duyarlılığınısaptamak için sadece sıvı mikrodilüsyon testi önerilmektedir. Ancak sıvı mikrodilüsyon testlerininzaman alıcı ve zahmetli olması nedeniyle rutin laboratuvarlarında hızlı ve güvenilir kolistin duyarlılığısonucu sağlayabilen testlere ihtiyaç duyulmaktadır. Bu çalışmada, Klebsiella pneumoniae veAcinetobacter baumannii kökenlerinde kolistin duyarlılığının saptanmasında ticari olarak hazır olaraküretilen Diagnostics MIC-COL (Diagnostics I.n.c., Galanta, Slovakya) testinin performansının değerlendirilmesi amaçlanmıştır. Rutin laboratuvarımızda 2016-2019 yılları arasında çeşitli klinik örneklerden izole edilen K.pneumoniae (n=22) ve A.baumannii (n=28) kökenleri çalışmaya dahil edilmiştir.Kökenlerin kolistin minimum inhibitör konsantrasyonları (MİK) hem referans yöntem olan sıvı mikrodilüsyon yöntemi ile hem de ticari olarak üretilen Diagnostics MIC-COL testi ile çalışılmıştır. Elde edilensonuçlar karşılaştırılarak testin temel uyum, kategorik uyum, büyük hata ve çok büyük hata oranlarıhesaplanmıştır. Sıvı mikrodilüsyon yöntemi ile karşılaştırıldığında Diagnostics MIC-COL testinin temeluyumu % 84, kategorik uyumu % 98, büyük hata oranı % 3,8 olarak tespit edilirken çok büyük hatatespit edilmemiştir. Rutin laboratuvarlarda hızlı ve güvenilir kolistin duyarlılığının tespit edilerek tedavinin yönlendirilmesi oldukça önemlidir. Çalışmamızda kullanılan ticari test kullanımı kolay ve zamanalıcı olmayan bir testtir. Ayrıca strip şeklinde olması sayesinde her izolat ayrı çalışılabilmektedir.Büyük hata oranının beklenilen değerlerin üzerinde olması nedeniyle daha fazla sayıda ve farklıdirenç düzeylerine sahip kökenlerle yapılacak ileri çalışmalarla bu oranların yeniden değerlendirilmesi faydalı olacaktır.Due to the limited number of antimicrobials to be used in the treatment of infections caused by_x000D_ Gram-negative microorganisms with multi-drug resistance recently, old antibiotics such as colistin_x000D_ have started to be preferred frequently. However, some problems are encountered in antibiotic_x000D_ susceptibility tests (disk diffusion, gradient test, automated systems) which are frequently used in the_x000D_ routine laboratory due to the cationic nature of colistin. For this reason, only the broth microdilution_x000D_ test is recommended by European Committee on Antimicrobial Susceptibility Testing (EUCAST) and_x000D_ Clinical and Laboratory Standards Institute (CLSI) for the detection of colistin susceptibility. Since_x000D_ broth microdilution tests are time consuming and inconvenient, tests that can provide fast and_x000D_ reliable colistin susceptibility result is needed in routine laboratories. In this study, it was aimed to_x000D_ evaluate the performance of the commercially produced Diagnostics MIC-COL test (Diagnostics I.n.c,_x000D_ Galanta, Slovakia) for the detection of colistin susceptibility in Klebsiella pneumoniae and_x000D_ Acinetobacter baumannii strains. The strains of K.pneumoniae (n = 22) and A.baumannii (n = 28)_x000D_ isolated from various clinical specimens between 2016 and 2019 in our routine laboratory were_x000D_ included in the study. Colistin minimum inhibitory concentrations (MIC) of the strains were studied_x000D_ with both the reference broth microdilution method and the commercially produced Diagnostics_x000D_ Colistin MIC-COL test. The essential agreement, categorical agreement, major error, and very major_x000D_ error rates of the test were calculated by comparing the obtained results. The essential agreement_x000D_ of the Diagnostics Colistin MIC-Strip test was determined as 84 %, categorical agreement as 98 %,_x000D_ and major error rate as 3.8 %, while no very major error was detected. İt is very important to guide_x000D_ antimicrobial treatment with rapid and reliable detection of colistin susceptibility. The commercial_x000D_ test used in our study is easy to use and not time-consuming. Also, due to its strip from, each isolate_x000D_ can be studied separately. Because of the major error rate being above the expected values, it will be_x000D_ useful to re-evaluate these rates with further studies to be conducted with a larger number of strains_x000D_ with different resistance levels

Results from the Survey of Antibiotic Resistance (SOAR) 2011-13 in Turkey

Objectives: Data are presented from the Survey of Antibiotic Resistance (SOAR) for respiratory tract infection pathogens collected in 2011-13 from Turkey. Methods: MICs were determined using Etest (R). Susceptibilitywas assessed using CLSI, EUCASTand pharmacokinetic/pharmacodynamic (PK/PD) interpretive criteria. Results: Rates of antibiotic susceptibility were very low among 333 isolates of Streptococcus pneumoniae tested: penicillin 38% using CLSI (oral) and EUCAST breakpoints; erythromycin 51% using CLSI and EUCAST criteria; and cefuroxime 64.6% using CLSI and PK/PD and 46.9% using EUCAST. Of the isolates, >90% were susceptible to amoxicillin/clavulanic acid, ceftriaxone (except using EUCAST criteria: 76%), levofloxacin and high-dose intravenous penicillin. Among 339 Haemophilus influenzae isolates, 6.8% were beta-lactamase positive while 9.1% were beta-lactamase negative but ampicillin resistant (BLNAR) by CLSI (14.7% by EUCAST) criteria. Amoxicillin/clavulanic acid susceptibility was similar to 90% by CLSI (with or without BLNAR adjustment, EUCAST and high-dose PK/PD) but lower, at 82.9%, by EUCAST with BLNAR adjustment. Levofloxacin susceptibility was 96% using all three breakpoints. Dramatic differences in rates of susceptibility, depending on the breakpoints used, were seen for cefaclor [ 94% by CLSI (86.4% BLNAR adjusted), 23% by PK/PD] and cefuroxime [97% by CLSI (89.1% BLNAR adjusted), 85% by PK/PD, 15% by EUCAST (13.0% BLNAR adjusted)]. Streptococcus pyogenes (n = 222) and Moraxella catarrhalis (n = 40) isolates remained highly susceptible to amoxicillin/clavulanic acid, cephalosporins and levofloxacin, with only erythromycin susceptibility dropping below 95% for S. pyogenes. Conclusions: Overall, amoxicillin/clavulanic acid and levofloxacin were themost active antibiotics based on all three breakpoints against these pathogens. Although susceptibility was not universally low in Turkey, high resistance rates were found in S. pneumoniae and, when using PK/PD and EUCAST breakpoints, in other respiratory pathogens

EUCAST rapid antimicrobial susceptibility testing (RAST) in blood cultures

Abstract Objectives When bloodstream infections are caused by resistant bacteria, rapid antimicrobial susceptibility testing (RAST) is important for adjustment of therapy. The EUCAST RAST method, directly from positive blood cultures, was validated in a multi-laboratory study in Europe. Methods RAST was performed in 40 laboratories in northern Europe (NE) and 15 in southern Europe (SE) from clinical blood cultures positive for Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus or Streptococcus pneumoniae. Categorical results at 4, 6 and 8 h of incubation were compared with results for EUCAST standard 16–20 h disc diffusion. The method, preliminary breakpoints and the performance of the laboratories were evaluated. Results The total number of isolates was 833/318 in NE/SE. The number of zone diameters that could be read (88%, 96% and 99%) and interpreted (70%, 81% and 85%) increased with incubation time (4, 6 and 8 h). The categorical agreement was acceptable, with total error rates in NE/SE of 2.4%/4.9% at 4 h, 1.1%/3.5% at 6 h and 1.1%/3.3% at 8 h. False susceptibility at 4, 6 and 8 h of incubation was below 0.3% and 1.1% in NE and SE, respectively, and the corresponding percentages for false resistance were below 1.9% and 2.8%. After fine-tuning breakpoints, more zones could be interpreted (73%, 89% and 93%), with only marginally affected error rates. Conclusions The EUCAST RAST method can be implemented in routine laboratories without major investments. It provides reliable antimicrobial susceptibility testing results for relevant bloodstream infection pathogens after 4–6 h of incubation

Three-year study of health care-associated infections in a Turkish pediatric ward

Introduction: Health care-associated infections (HCAIs) can cause an increase in morbidity, mortality and costs, especially in developing countries. As information on the epidemiology of HCAIs in pediatric patientsinTurkey is limited, we decided to study the annual incidence and antibiotic resistance patterns in our pediatric ward at Marmara University Hospital. Methodology: All hospitalized patients in the pediatric ward were assessed with regard to HCAIs betweenJanuary 1, 2008 and December 31, 2010. Data was prospectively collected according to standard protocols of the National Nosocomial Infections Surveillance System (NosoLINE). Results: A total of 16.5% of all hospitalized patients developed HCAIs in the three years studied. The most frequent HCAIs were urinary tract infections (UTI) (29.3%), bloodstream infections (27%) and pneumonias (21%). While the most frequent agent isolatedfrom UTI was Escherichia coli (26%), the most common agent in blood stream infections was Staphylococcus epidermidis (30.4%). Vancomycin resistance was found in 73.3% of all Enterococcus faecium strains. Extended-spectrum beta-lactamase was detected in 58.3% of Klebsiella pneumoniae and E. coli isolates. Conclusions: Continual HCAI surveillance is important to determineits rate. Knowledge of the HCAI incidence can influence people's use of broad-spectrum antibiotics and encourage antibiotic rotation. Moreover, the knowledge of HCAI incidence may support the infection control programmes, including education and isolation methods which ultimately may help to reducethe rate of the HCAIs

Molecular characterization and risk factors for carbapenem-resistant Gram-negative bacilli colonization in children: emergence of NDM-producing Acinetobacter baumannii in a newborn intensive care unit in Turkey

Background: Multidrug-resistant Gram-negative bacilli are responsible for more than 50% of healthcare-associated infections. Colonization dynamics, characteristics, and risk factor data for CR-GNB are scarce in children. Aim: To examine the molecular characteristics of, and risk factors for nosocomial colonization with, carbapenem-resistant Gram-negative bacilli (CR-GNB) in hospitalized paediatric patients in a tertiary university hospital's paediatric units in Turkey. Methods: A prospective case-control study was performed at a university hospital in Istanbul, Turkey. Findings: A total of 1840 rectal swab specimens were collected from all 762 hospitalized children between March 2013 and October 2013. Among them, 176 (23%) patients were colonized with CR-GNB. Of these, 72 (9%) patients were colonized with carbapenem-resistant Enterobacteriaceae, 138 (18%) with CR-non-fermenter Gram-negative bacilli (CR-NF) and 34 (4%) with both. The median CR-GNB colonization time was 10 days (range: 1-116). The median duration of rectal colonization with CR-GNB was 8 days (range: 1-160). NDM (31%) was the second most frequent carbapenemase identified in Acinetobacter baumannii isolates, and has not previously been detected in Turkey. All of the 17 patients colonized with NDM-producing A. baumannii were newborns in the neonatal intensive care unit. Independent risk factors for CR-GNB colonization were: age <1 year, nasogastric tube placement, presence of underlying chronic diseases, ampicillin usage, surgical intervention, and carbapenem use

Recurrent Bacterial Meningitis in a Child with Mondini Dysplasia

Mondini dysplasia, also known as Mondini malformation, is a developmental abnormality of the inner and middle ears that can cause hearing loss, cerebrospinal fluid (CSF) leakage, and recurrent bacterial meningitis (RBM), which is defined as two or more episodes of meningitis separated by a period of convalescence and the complete resolution of all signs and symptoms. An accurate diagnosis of the underlying pathology is crucial to prevent further episodes from occurring. Herein, we present a three-year-old boy with RBM and unilateral sensorineural hearing loss. During the evaluation to determine the etiology of the RBM, cystic malformation in the cochlea and vestibular dilatation consistent with Mondini dysplasia were detected via computerized tomography (CT) of the temporal bone

Investigation of IBC-1, a Rare Plasmid-Mediated Class A Beta-lactamase in Members of Enterobacterales

Amaç: Bu çalışmanın amacı, tüm dünyada sıklıkla gözlemlenen geniş spektrumlu beta laktamazları (GSBL) TEM, SHV ve CTX-M ve nadir görülen IBC-1 beta laktamaz enziminin varlığını araştırmaktır. Gereç ve Yöntem: Marmara Üniversitesi Hastanesinde yatan hastaların klinik örneklerinden izole edilen, fenotipik olarak GSBL üreten ve IBC-1 fenotipi gösteren 30 köken çalışmaya dahil edilmiştir. Antibiyotik duyarlılık testleri disk difüzyon ve agarda dilüsyon yöntemi ile gerçekleştirilmiştir. GSBL enzimlerinin fenotipik olarak saptanmasında E-test ve çift disk sinerji yöntemi kullanılmıştır. GSBL üretiminden sorumlu olan genlerinin varlığını saptamak amacıyla polimeraz zincir reaksiyonu (PZR) yapılmıştır.Bulgular: Kökenlerin tamamı, imipeneme duyarlı bulunurken, ampisilin, amoksisilin klavulanik asit, piperasilin, seftazidim ve trimetoprim sülfametaksazole dirençli olarak; saptanmıştır. E-test yöntemiyle 4 köken tanımsız, 26 köken ise GSBL pozitif saptanmıştır. Çift disk sinerji yöntemi ile 2 köken fenotipik olarak IBC-1 pozitif iken, 5 köken şüpheli pozitif olarak belirlenmiştir. Kökenlerimizin blaTEM, blaSHV ve blaCTX-M genlerini taşıma oranı sırasıyla %73,3, %60 ve %56,6 olarak belirlenmiştir. blaIBC geni ise hiçbir kökende saptanmamıştır. Sonuç: İlk olarak Yunanistan’da saptanan IBC-1 enzimi ülkemiz için henüz bir tehlike oluşturmazken GSBL pozitif kökenlerde TEM, SHV ve CTX-M enzimlerinin oranı oldukça yüksek olarak tespit edilmiştir.Objective: The aim of the study was to investigate the presence of _x000D_ extended -spectrum beta-lactamases (ESBL) TEM, SHV, and CTX-M _x000D_ which are frequently observed all over the world, and the rare IBC?1 beta-lactamase enzyme. _x000D_ Material and Method: Thirty strains that isolated from various _x000D_ clinical samples from inpatient at Marmara University Hospital, _x000D_ which were phenotypically positive for ESBL, and IBC-1were in?cluded in the study. Antimicrobial susceptibility tests were per?formed both by disk diffusion and agar dilution tests. E-test and _x000D_ double-disc synergy method (DDS) were used for phenotypic _x000D_ detection of ESBLs. The presence of ESBL genes was detected by _x000D_ polymerase chain reaction (PCR)._x000D_ Results: All strains were susceptible to imipenem while ampicil?lin, amoxicillin-clavulanic acid, piperacillin, ceftazidime, and tri?methoprim-sulfamethoxazole were resistant. While 4 strains were _x000D_ unidentified, 26 strains were detected as ESBL positive by E-test. _x000D_ Two strains were phenotypically positive for IBC-1 with DDS, while _x000D_ 5 strains were identified as doubtful. The rate of carrying the blaTEM, _x000D_ blaSHV, and blaCTX-M genes of strains was 73.3%, 60%, and 56.6%, _x000D_ respectively. The blaIBC gene was not detected in any of the strains._x000D_ Conclusion: While the IBC-1 enzyme, which was first detected in _x000D_ Greece, have not caused a threat to our country yet, the rate of _x000D_ TEM, SHV, and CTX-M enzymes were found to be quite high

Evaluation of phenotypic tests for detection of carbapenemases: New modifications with new interpretation

Introduction: The emergence and spread of carbapenemase-producing Enterobacterales (CPE) is a worldwide public health threat. Rapid and accurate detection of CPE is essential to prevent their dissemination within health care settings. The aim of this study was to evaluate the performance of CIM, mCIM and mCIM with ammonium bicarbonate (mCIM-A) methods by using different interpretation criteria for detection of carbapenemases. Methods: One hundred and fifty-three Klebsiella pneumoniae isolates previously characterized by molecular tests, including 133 carbapenemase producers and 20 non-carbapenemase producers, were collected in this study. CIM and mCIM tests were performed as described previously. mCIM-A by adding 50 mM ammonium bicarbonate to the bacterial suspension prepared in tryptic soy broth. The inhibition zone diameter of around meropenem disc was measured and interpreted as positive according to i) Pierce and colleagues (<19 mm), ii) EUCAST meropenem susceptibility breakpoint (<22). Results: CIM, although seems to be good for carbapenemases other than OXA-48-like and NDM, is not satisfactory (42.3% and 83.4%, respectively) for those enzymes with any of the interpretation criteria. OXA-48-like and NDM were detected with a better performance (88.7% and 92.8, respectively) with mCIM when results were interpreted according to <22 mm zone diameter for OXA-48-like and NDM. The best results were obtained with mCIM-A using <22 mm criteria without any difference in the results of other enzymes and negative strains. Conclusions: mCIM- A method interpreted with <22 mm meropenem zone diameter seems to be preferable compared to CIM and mCIM. mCIM-A is simple and useful tool for identification of CPEs in clinical microbiology laboratories. (C) 2020 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved