Antimicrobial Susceptibility Data Research Articles

Clinical Implication of Drug Resistance for H. pylori Management.

Rates of antimicrobial-resistance among H. pylori strains are increasing worldwide, resulting in declining eradication rates with current therapies, especially those containing clarithromycin or levofloxacin. To improve H. pylori management, a paradigm shift is needed, from the empiric approaches formerly employed, to regimen selection based upon knowledge of local and patient-level antimicrobial susceptibility data. We review the mechanisms of H. pylori antimicrobial resistance and the available worldwide pattern of resistance to key antimicrobials used in H. pylori therapy. The practicalities and challenges of measuring susceptibility in clinical practice is discussed, including not only conventional culture-based techniques but also novel sequencing-based methods performed on gastric tissue and stool samples. Though clinical trials of "tailored" (susceptibility-based) treatments have yet to show the clear superiority of tailored over empiric regimen selection, the ability to measure and modify treatment based upon antimicrobial susceptibility testing is likely to become more frequent in clinical practice and should lead to improved H. pylori management in the near future.

High rate of fluoroquinolone resistant Neisseria gonorrhoeae detected by molecular surveillance of antimicrobial resistance determinants in Bulgaria

Antimicrobial-resistant Neisseria gonorrhoeae is a major public health concern. The surveillance of antimicrobial resistance benefits from rapid and accurate molecular techniques in molecular diagnostics to facilitate individualised medicine and antimicrobial stewardship. To support the recommendations for empirical treatment of gonococcal infections in Bulgaria, we investigated N. gonorrhoeae-positive clinical specimens from 2018 to 2021 for the presence of genetic determinants associated with antimicrobial resistance. N. gonorrhoeae-positive samples stored at the National Center of Infectious and Parasitic Diseases during the four-year study period were retrospectively analysed by polymerase chain reaction and DNA sequencing assays for resistance determinants to fluoroquinolones, third-generation cephalosporins and macrolides. The detected determinants indicated a high rate of fluoroquinolone resistance (59%), very low level of decreased susceptibility to third-generation cephalosporins (3%) but no macrolide resistance (0%). These findings validate the utilisation of the international guidelines’ recommendations for empirical dual therapy with ceftriaxone/cefixime and azithromycin in Bulgaria. Because of the high fluoroquinolone resistance rate, ciprofloxacin should only be considered as treatment if phenotypic or molecular antimicrobial susceptibility data indicate susceptibility to ciprofloxacin. For the purposes of surveillance and individualised medicine, molecular assays for resistance determinants could complement culture-based phenotypic gonococcal antimicrobial resistance testing.

Revisiting conventional microbiology techniques in the era of molecular testing

The diagnosis of infectious diseases has always been a matter of concern for clinicians worldwide. Although the conventional techniques like microscopy and culture have served the purpose since ages, they have been found to be inadequate now with the advent of modern technology including automated identification systems and molecular testing. The newer technology including Matrix-Assisted Laser Desorption Ionization – Time of Flight and molecular tests such as multiplex polymerase chain reactions and Next Generation Sequencing, has undoubtedly paved the way for diagnosis and discovery of various novel pathogens. This has subsequently given rise to a mindset that the conventional techniques are redundant and hence, should be abandoned. The authors, through the current review, would like to present a perspective in favour of the conventional techniques which still are one of the simplest, most inexpensive methods for diagnosing infectious diseases and provide us with the precious antimicrobial susceptibility data to guide our antimicrobial stewardship programmes. Further, considering the limited availability of the state-of-the-art molecular testing facilities across the country, it is recommended that rather than using them exclusively or separately, conventional methods and the molecular tests be used in conjunction wherever available and feasible.

Epidemiological Cutoff Values for Standard Broth Microdilution Susceptibility Testing of Flavobacterium columnare Isolated from Fishes.

Flavobacterium columnare, the causative agent of columnaris disease in a large variety of freshwater fish, is a major problem in commercial aquaculture. A limited number of antimicrobial therapies are available to control this disease; therefore, these agents must be used judiciously. To facilitate effective monitoring for changes in susceptibility, the Clinical Laboratory Standards Institute (CLSI) has a standard broth microdilution test method specific for F. columnare. However, there are no CLSI-approved criteria (termed epidemiological cutoff values [ECVs]) to interpret results. Nevertheless, researchers have developed provisional ECVs based on testing by one laboratory. To satisfy CLSI data requirements, three laboratories used the standard method to generate additional antimicrobial susceptibility data against ampicillin, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, oxolinic acid, oxytetracycline, sulfadimethoxine/ormetoprim, and sulfamethoxazole-trimethoprim using 109 F. columnare isolates. The new data combined with previously published data from 120 F. columnare isolates were analyzed and ECVs proposed to CLSI. Of the 10 antimicrobials, ECVs were approved for ampicillin, enrofloxacin, erythromycin, florfenicol, flumequine, oxolinic acid, and oxytetracycline, which were published in the 2020 edition of the CLSI document VET04 performance standards. These ECVs will help microbiologists categorize decreased antimicrobial susceptibility among F. columnare and will help in surveillance efforts to ensure judicious antimicrobial use.

The Microbiological Etiology of Fracture-Related Infection.

PurposeFracture-related infection (FRI) is an important complication related to orthopaedic trauma. Although the scientific interest with respect to the diagnosis and treatment of FRI is increasing, data on the microbiological epidemiology remains limited. Therefore, the primary aim of this study was to evaluate the microbiological epidemiology related to FRI, including the association with clinical symptoms and antimicrobial susceptibility data. The secondary aim was to analyze whether there was a relationship between the time to onset of infection and the microbiological etiology of FRI.MethodsFRI patients treated at the University Hospitals of Leuven, Belgium, between January 1st 2015 and November 24th 2019 were evaluated retrospectively. The microbiological etiology and antimicrobial susceptibility data were analyzed. Patients were classified as having an early (<2 weeks after implantation), delayed (2-10 weeks) or late-onset (> 10 weeks) FRI.ResultsOne hundred ninety-one patients with 194 FRIs, most frequently involving the tibia (23.7%) and femur (18.6%), were included. Staphylococcus aureus was the most frequently isolated pathogen, regardless of time to onset (n=61; 31.4%), followed by S. epidermidis (n=50; 25.8%) and non-epidermidis coagulase-negative staphylococci (n=35; 18.0%). Polymicrobial infections (n=49; 25.3%), mainly involving Gram negative bacilli (GNB) (n=32; 65.3%), were less common than monomicrobial infections (n=138; 71.1%). Virulent pathogens in monomicrobial FRIs were more likely to cause pus or purulent discharge (n=45;54.9%; p=0.002) and fistulas (n=21;25.6%; p=0.030). Susceptibility to piperacillin/tazobactam for GNB was 75.9%. Vancomycin covered 100% of Gram positive cocci.ConclusionThis study revealed that in early FRIs, polymicrobial infections and infections including Enterobacterales and enterococcal species were more frequent. A time-based FRI classification is not meaningful to estimate the microbiological epidemiology and cannot be used to guide empiric antibiotic therapy. Large multicenter prospective studies are necessary to gain more insight into the added value of (broad) empirical antibiotic therapy.

National surveillance of Neisseria gonorrhoeae antimicrobial susceptibility and epidemiological data of gonorrhoea patients across Brazil, 2018-20.

ObjectivesTo (i) describe the nationwide antimicrobial susceptibility of Neisseria gonorrhoeae (NG) isolates cultured across Brazil in 2018–20 and compare it with NG antimicrobial resistance data from 2015–16, and (ii) present epidemiological data of the corresponding gonorrhoea patients in 2018–20.MethodsTwelve representative sentinel sites cultured NG isolates from men with urethral discharge. Susceptibility to eight antimicrobials was examined using agar dilution method, according to WHO standards. The consenting participants were invited to provide epidemiological data.ResultsIn total, 633 NG isolates (one isolate per participant) were analysed, and 449 (70.9%) questionnaires were answered. Heterosexual (68.2%) and homosexual (23.1%) sexual orientations were common, and most prevalent types of unprotected sexual intercourse were vaginal insertive (69.9%), oral giving (56.6%) and anal insertive (47.4%). The levels of in vitro NG resistance to ciprofloxacin, tetracycline, benzylpenicillin, azithromycin, cefixime, gentamicin, spectinomycin and ceftriaxone were 67.3%, 40.0%, 25.7%, 10.6%, 0.3%, 0%, 0% and 0%, respectively. Compliance with the recommended first-line ceftriaxone 500 mg plus azithromycin 1 g therapy was high (90.9%).ConclusionsCompared with 2015–16, ciprofloxacin resistance has remained high and azithromycin and cefixime resistance rates have increased in Brazil. Resistance remained lacking to ceftriaxone, gentamicin and spectinomycin, which all are gonorrhoea treatment options. The increasing azithromycin resistance in Brazil and internationally may threaten the future use of azithromycin in dual regimens for treatment of gonorrhoea. Consequently, continued and enhanced quality-assured surveillance of gonococcal AMR, and ideally also treatment failures and including WGS, is imperative in Brazil and worldwide.

Uropathogens and the Antibiogram Profile from a Tertiary Care Hospital

Background: Urinary tract infections (UTIs) are one of the most common bacterial infections in humans, both in the community and the hospital settings. The distribution of antimicrobial susceptibility data of UTI-causing microorganisms changes from time to time and from place to place. The susceptibility data provided by regional microbiology laboratories helps to choose the empirical antimicrobials to treat UTI. Aim and Objectives: To determine the prevalence and antimicrobial drug susceptibility pattern of the bacterial uropathogens isolated from a tertiary care hospital. Material and Methods: A retrospective analysis over a period of two months (Jan-Feb 2021) was performed in the Department of Microbiology of a tertiary care hospital, East part of Delhi. These two months were immediately following conversion of this facility to a non COVID centre from a dedicated COVID centre. Culture results of the urine samples received during the study period were analyzed. The samples were processed according to standard guidelines. The data were entered into micro soft excel for analysis. Results: A total of 1650 urine samples from suspected UTIs were analyzed retrospectively for isolation and identification of bacteria and antimicrobial susceptibility testing. 271 (16.4%) grew significant microorganisms including fungus. In both male and female patients E. coli (n = 46, 17%) was the most commonly isolated microorganism, followed by Staphylococcus spp. (n = 45, 16%). Isolated resistance to uropathogens was common with Cotrimoxazole (60%), Nitrofurantoin (50%), ciprofloxacin (50%), tetracycline (45%), Imipenem and cefotaxime (35%) Conclusions: UTI is one of the most common infectious diseases that clinicians are dealing with. Increasing antimicrobial resistance among uropathogens implicated in UTI is a matter of concern. Periodic monitoring of etiology and drug susceptibility is recommended.

Epidemiology, Antimicrobial Resistance, and Virulence Determinants of Group B Streptococcus in an Australian Setting.

Streptococcus agalactiae [group B Streptococcus (GBS)] is a major neonatal pathogen and also causes invasive disease in non-pregnant adults. One hundred GBS isolates (n = 50 invasive disease and n = 50 colonizing pregnant women) were characterized using capsular serotyping by latex agglutination, antimicrobial susceptibility testing, and whole genome sequencing (WGS). All isolates were susceptible to penicillin, 32% were resistant to clindamycin. Of these, two isolates had reduced susceptibility to ceftriaxone (MIC 0.75 mg/L) and were found to have unique alleles at pbp2X and pbp1A. Capsular serotypes Ia (18%), III (18%), Ib (14%), V (12%), and VI (11%) were most common and comparison of latex agglutination and capsular genotyping by WGS showed 71% agreement. Less common capsular genotypes VI–VIII represented 15% of isolates, indicating that a significant proportion may not be targeted by the proposed pentavalent or hexavalent vaccines under development. WGS is a useful aid in GBS surveillance and shows correlation to phenotypic serotyping and antimicrobial susceptibility data.

Mass spectrometry in research laboratories and clinical diagnostic: a new era in medical mycology.

Diagnosis by clinical mycology laboratory plays a critical role in patient care by providing definitive knowledge of the cause of infection and antimicrobial susceptibility data to physicians. Rapid diagnostic methods are likely to improve patient. Aggressive resuscitation bundles, adequate source control, and appropriate antibiotic therapy are cornerstones for success in the treatment of patients. Routine methods for identifying clinical specimen fungal pathogen are based on the cultivation on different media with the subsequent examination of its phenotypic characteristics comprising a combination of microscopic and colony morphologies. As some fungi cannot be readily identified using these methods, molecular diagnostic methods may be required. These methods are fast, but it can cost a lot. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is suitable for high-throughput and rapid diagnostics at low costs. It can be considered an alternative for conventional biochemical and molecular identification systems in a microbiological laboratory. The reliability and accuracy of this method have been scrutinized in many surveys and have been compared with several methods including sequencing and molecular methods. According to these findings, the reliability and accuracy of this method are very high and can be trusted. With all the benefits of this technique, the libraries of MALDI-TOF MS need to be strengthened to enhance its performance. This review provides an overview of the most recent research literature that has investigated the applications and usage of MT-MS to the identification of microorganisms, mycotoxins, antifungal susceptibility examination, and mycobiome research.

Bacterial genotypic and patient risk factors for adverse outcomes in Escherichia coli bloodstream infections: a prospective molecular epidemiological study.

Objectives Escherichia coli bloodstream infections have shown a sustained increase in England, for reasons that are unknown. Furthermore, the contribution of MDR lineages such as ST131 to overall E. coli disease burden and outcome is undetermined.MethodsWe genome-sequenced E. coli blood isolates from all patients with E. coli bacteraemia in north-west London from July 2015 to August 2016 and assigned MLST genotypes, virulence factors and AMR genes to all isolates. Isolate STs were then linked to phenotypic antimicrobial susceptibility, patient demographics and clinical outcome data to explore relationships between the E. coli STs, patient factors and outcomes.ResultsA total of 551 E. coli genomes were analysed. Four STs (ST131, 21.2%; ST73, 14.5%; ST69, 9.3%; and ST95, 8.2%) accounted for over half of cases. E. coli genotype ST131-C2 was associated with phenotypic non-susceptibility to quinolones, third-generation cephalosporins, amoxicillin, amoxicillin/clavulanic acid, gentamicin and trimethoprim. Among 300 patients from whom outcome was known, an association between the ST131-C2 lineage and longer length of stay was detected, although multivariable regression modelling did not demonstrate an association between E. coli ST and mortality. Several unexpected associations were identified between gentamicin non-susceptibility, ethnicity, sex and adverse outcomes, requiring further research.ConclusionsAlthough E. coli ST was associated with defined antimicrobial non-susceptibility patterns and prolonged length of stay, E. coli ST was not associated with increased mortality. ST131 has outcompeted other lineages in north-west London. Where ST131 is prevalent, caution is required when devising empiric regimens for suspected Gram-negative sepsis, in particular the pairing of β-lactam agents with gentamicin.

Prediction of antimicrobial minimal inhibitory concentrations for Neisseria gonorrhoeae using machine learning models

The lowest concentration of an antimicrobial agent that can inhibit the visible growth of a microorganism after overnight incubation is called as minimum inhibitory concentration (MIC) and the drug prescriptions are made on the basis of MIC data to ensure successful treatment outcomes. Therefore, reliable antimicrobial susceptibility data is crucial, and it will help clinicians about which drug to prescribe. Although few prediction studies based on strategies have been conducted, however, no single machine learning (ML) modelling has been carried out to predict MICs in N. gonorrhoeae. In this study, we propose a ML based approach that can predict MICs of a specific antibiotic using unitigs sequences data. We retrieved N. gonorrhoeae genomes from European Nucleotide Archive and NCBI and analysed them combined with their respective MIC data for cefixime, ciprofloxacin, and azithromycin and then we constructed unitigs by using de Brujin graphs. We built and compared 35 different ML regression models to predict MICs. Our results demonstrate that RandomForest and CATBoost models showed best performance in predicting MICs of the three antibiotics. The coefficient of determination, R2, (a statistical measure of how well the regression predictions approximate the real data points) for cefixime, ciprofloxacin, and azithromycin was 0.75787, 0.77241, and 0.79009 respectively using RandomForest. For CATBoost model, the R2 value was 0.74570, 0.77393, and 0.79317 for cefixime, ciprofloxacin, and azithromycin respectively. Lastly, using feature importance, we explore the important genomic regions identified by the models for predicting MICs. The major mutations which are responsible for resistance against these three antibiotics were chosen by ML models as a top feature in case of each antibiotics. CATBoost, DecisionTree, GradientBoosting, and RandomForest regression models chose the same unitigs which are responsible for resistance. This unitigs-based strategy for developing models for MIC prediction, clinical diagnostics, and surveillance can be applicable for other critical bacterial pathogens.

Whole-genome sequencing of Chlamydia trachomatis isolates from persistently infected patients

Current understanding of the causes of treatment failure in Chlamydia trachomatis is poor and antimicrobial susceptibility data are lacking. We used genome sequencing to seek evidence of antimicrobial resistance in isolates sourced from patients who were persistently infected. Genomic DNA was extracted from C. trachomatis isolates cultured in McCoy cell monolayers. Sequencing libraries were prepared using the SureSelectXT Illumina paired-end protocol. Paired reads were mapped against a reference genome and single nucleotide variants (SNVs) were identified. Seven isolates from persistently infected patients and five isolates from successfully treated patients were sequenced. No previously reported SNVs associated with antimicrobial resistance were found. A unique SNV was identified in the gyrA gene of one treatment failure isolate but was located outside of the quinolone resistance determining region; this SNV has been previously reported in other members of the Chlamydiaceae family. No genomic evidence was found to explain the differences in clinical outcome for our two groups of patients. A mutation unrelated to antimicrobial susceptibility was found in an isolate from a persistently infected patient. The cause of these persistent infections with C. trachomatis remains unclear.

Increment Antimicrobial Resistance During the COVID-19 Pandemic: Results from the Invifar Network.

Aim: This study aims to assess the changes in antimicrobial resistance among some critical and high-priority microorganisms collected previously and during the coronavirus disease 2019 (COVID-19) pandemic in Mexico. Methods: We collected antimicrobial susceptibility data for critical and high-priority microorganisms from blood, urine, respiratory samples, and from all specimens, in which the pathogen may be considered a causative agent. Data were stratified and compared for two periods: 2019 versus 2020 and second semester 2019 (prepandemic) versus the second semester 2020 (pandemic). Results: In the analysis of second semester 2019 versus the second semester 2020, in blood samples, increased resistance to oxacillin (15.2% vs. 36.9%), erythromycin (25.7% vs. 42.8%), and clindamycin (24.8% vs. 43.3%) (p ≤ 0.01) was detected for Staphylococcus aureus, to imipenem (13% vs. 23.4%) and meropenem (11.2% vs. 21.4) (p ≤ 0.01), for Klebsiella pneumoniae. In all specimens, increased ampicillin and tetracycline resistance was detected for Enterococcus faecium (p ≤ 0.01). In cefepime, meropenem, levofloxacin, and gentamicin (p ≤ 0.01), resistance was detected for Escherichia coli; and in piperacillin-tazobactam, cefepime, imipenem, meropenem, ciprofloxacin, levofloxacin, and gentamicin (p ≤ 0.01), resistance was detected for Pseudomonas aeruginosa. Conclusion: Antimicrobial resistance increased in Mexico during the COVID-19 pandemic. The increase in oxacillin resistance for S. aureus and carbapenem resistance for K. pneumoniae recovered from blood specimens deserves special attention. In addition, an increase in erythromycin resistance in S. aureus was detected, which may be associated with high azithromycin use. In general, for Acinetobacter baumannii and P. aeruginosa, increasing resistance rates were detected.

Clinical Implication of the Relationship between Antimicrobial Resistance and Infection Control Activities in Japanese Hospitals: A Principal Component Analysis-Based Cluster Analysis.

There are few multicenter investigations regarding the relationship between antimicrobial resistance (AMR) and infection-control activities in Japanese hospitals. Hence, we aimed to identify Japanese hospital subgroups based on facility characteristics and infection-control activities. Moreover, we evaluated the relationship between AMR and hospital subgroups. We conducted a cross-sectional study using administrative claims data and antimicrobial susceptibility data in 124 hospitals from April 2016 to March 2017. Hospitals were classified using cluster analysis based the principal component analysis-transformed data. We assessed the relationship between each cluster and AMR using analysis of variance. Ten variables were selected and transformed into four principal components, and five clusters were identified. Cluster 5 had high infection control activity. Cluster 2 had partially lower activity of infection control than the other clusters. Clusters 3 and 4 had a higher rate of surgeries than Cluster 1. The methicillin-resistant Staphylococcus aureus (MRSA)/S. aureus detection rate was lowest in Cluster 1, followed, respectively, by Clusters 5, 2, 4, and 3. The MRSA/S. aureus detection rate differed significantly between Clusters 4 and 5 (p = 0.0046). Our findings suggest that aggressive examination practices are associated with low AMR whereas surgeries, an infection risk factor, are associated with high AMR.

Staphylococcus lugdunensis Endocarditis: Lower Mortality in the Contemporary Era?

BackgroundStaphylococcus lugdunensis is a virulent coagulase-negative Staphylococcus that is a rare cause of infective endocarditis (IE) associated with high mortality. A linear growth of IE has occurred over the past several years in Saskatchewan, with overlapping epidemics of human immunodeficiency virus (HIV)/hepatitis C virus driven by injection drug use (IDU). We hypothesized that given the unique challenges faced by our population with IDU and inequitable healthcare access, our cases of S. lugdunensis IE might differ from those in the published literature. MethodsWe retrospectively reviewed the cases of S. lugdunensis endocarditis admitted at our tertiary care hospitals in Saskatoon over a 6-year period and analyzed their baseline characteristics, antimicrobial susceptibility data, management, and outcome data, where available, for each patient. ResultsOf the 24 blood cultures positive for S. lugdunensis, as identified by our laboratory, we verified 6 cases of definite IE, and 2 cases of probable IE, applying the modified Duke’s criteria. A total of 5 of 8 cases involved native valves, with only 1 infection of the bioprosthetic mitral valve, seen in patient with IDU. A total of 5 of 8 cases involved the left-sided valves, with 1 of 8 involving the tricuspid valve. Only 1 death was recorded. ConclusionsThe male predominance and primarily left-sided valve infection we noted in our review were similar to results in the published literature. We noted a lower rate of surgical intervention and mortality than previously observed, which merits further study. We did not find coinfection with HIV and/or hepatitis C virus as an epidemiologic risk factor, likely owing to the low rate of IDU in our study.

Antimicrobial Resistance Among Pathogens Causing Bloodstream Infections: A Multicenter Surveillance Report Over 20 Years (1998-2017).

PurposeBloodstream infections (BSIs) are a common consequence of infectious diseases and cause high morbidity and mortality. Appropriate antibiotic use is critical for patients’ treatment and prognosis. Long-term monitoring and analysis of antimicrobial resistance are important in guiding physicians to choose appropriate antibiotics and understand the changes in antimicrobial resistance and infection control. Here, we report a retrospective study on the trends of antimicrobial resistance in the common BSI-associated pathogens.MethodsThe identification of strains and antimicrobial susceptibility tests were performed in each anticipating hospital independently. Data from the Hubei Province Antimicrobial Resistance Surveillance System (HBARSS) from 1998 to 2017 were retrospectively analyzed using WHONET 5.6 software.ResultsData from HBARSS (1998–2017) revealed that 40,518 Gram-positive bacteria and 26,568 Gram-negative bacteria caused BSIs, the most common of which were Staphylococcus aureus and Escherichia coli. Salmonella typhi was a predominant BSI-associated pathogen in 1998–2003. Antimicrobial susceptibility data showed that the resistance rates of E. coli and Klebsiella pneumoniae to cefotaxime were significantly higher than those to ceftazidime. The proportion of strains of special antimicrobial resistance phenotypes including difficult-to-treat resistance (DTR), carbapenem-resistant (CR), extended-spectrum cephalosporin resistant (ECR) and fluoroquinolone resistant (FQR) in E. coli was 0.18%, 0.26%, 13.95%, 22.78% while in K. pneumoniae was 11.95%, 14.00%, 31.91% and 11.40%, respectively. In 2013–2017, K. pneumoniae showed resistance levels reaching 15.8% and 17.5% to imipenem and meropenem, respectively, and Acinetobacter baumannii showed high resistance rates ranging from 60 to 80% to common antibiotics. The detection rate of Salmonella typhi resistance to third-generation cephalosporins and fluoroquinolones was less than 5%. Control of methicillin-resistant Staphylococcus aureus (MRSA) remains a major challenge, and in 2009–2017, the MRSA detection rate was 40–50%.ConclusionPrevalence of CR K. pneumoniae has increased significantly in recent years. Resistance rates of A. baumannii to common antimicrobial agents have increased exponentially, reaching high levels. MRSA remains a challenge to control. For K. pneumoniae, DTR, CR, ECR and FQR were antimicrobial resistance phenotypes that could not be ignored while for E. coli DTR and CR were rare antimicrobial resistance phenotypes. CR K. pneumoniae, A. baumannii and MRSA present major challenges for controlling BSIs.

The Inhibitory Effect of Poly (DMAA-co-MMA) on Bacteria, Yeast and Dermatophyte Fungi Which Cause Serious Illnesses in People

In this study, it was researched the inhibitor effects of solutions including dichloromethane of poly dimethylacrylamide-co-methylmethacrylate P(DMAA-co-MMA) on microorganisms such as bacteria, yeast and dermatophyte fungi which cause serious illnesses in people. This solution, which was examined by the disc diffusion method, has antimicrobial feature upon preventing the proliferation of all bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus) and dermatophyte fungi except Bacillus megaterium and Klebsiella pneumoniae. In antimicrobial susceptibility data; poly P(DMAA-co-MMA) dissolved in dichloromethane has an inhibitory effect against the growth of yeast and dermatophyte fungi (on Candida spp. with 11.3 mm / inhibition area - 12.3 mm / inhibition area and 11.3 mm / inhibition area on Epidermophyton sp. - 11.3 mm / inhibition area on Trichophyton sp.) (P &amp;lt;0.001). MIC (Minimal inhibition concentration) breakpoints that strengthen the disk diffusion method are 50-100 μL (4500– 9000 μg in 10 mL) as the smallest value that inhibits the growth of bacteria, yeasts, dermatophyta. The antimicrobial compound can be of great advantage to illuminate future studies in this area. The polymer used in the study will provide a promising new addition to antimicrobial polymers that fight microorganisms that cause inflammation and fungal infections.

Clinical and bacteriological profile of urinary tract infection in children at a tertiary care hospital

Background: Urinary tract infection (UTI) is common in children and is an important cause of morbidity. UTI at young age can lead to renal injury and scarring, and ultimately lead to end stage renal disease in adulthood. Aim of the study The objectives of this study were to study the clinical and bacteriological profile of UTI in children.Methods: This prospective study was done in Sher-E-Bangla medical college hospital, Barishal from January 2018 to July 2019. A urine sample was included in our dataset if it demonstrated pure growth of a single organism and accompanying antimicrobial susceptibility and subject demographic data were available.Result: UTI was more common in female (70.0%) than in male (33.0%). Half were in the age group 1-5 years. Fever was the most common presentation (64.0%) followed by abdominal pain (42.0%), dysuria /increased frequency (34%), decreased appetite (28%). Escherichia coli was the most common (64%) bacterial isolate followed by Klebsiella sp. (20.0%) and Proteus sp. (14.0%). E. coli was highly sensitive to ofloxacin, cefotaxime and amikacin (94.0%). Klebsiella was 100% sensitive to ciprofloxacin and amikacin. Greater degree of resistance was seen to ampicillin, cotrimoxazole and nalidixic acid.Conclusions: Though various microorganisms are responsible for UTI in children, E. coli is the most common causative agent. Antimicrobial resistance has already emerged against many antibiotics, making empiric treatment of these infections challenging.

150. Improved Susceptibility of Pseudomonas aeruginosa to Cefepime (CEF) at a Veterans Tertiary Care Hospital, over a 7-Year Period (2011-2017): The Impact of Antibiotic Rotation/Cycling and Reversal of Drug Resistance in P. aeruginosa

Abstract Background Background: Pseudomonas aeruginosa continues to be an important cause of nosocomial infections associated with a high morbidity and mortality. Despite the availability of ceftazidime-avibactam (CAZ-AVI) and ceftolozone-tazobactam (CFT-TAZO), CEF continues to be an empiric agent of choice in several institutions. Aim: To evaluate the prevalence and trend in susceptibilities of P. aeruginosa to CEF over a 7-year period, identify possible correlation with the use of CAZ, AZT, PTZ, CIP, and CAR, (DOT/1000 patient days), as a quality improvement (QI) measure for optimizing CEF use, introduce antibiotic cycling as a tool to avoid emergence of drug-resistance in P. aeuriginosa. Methods A retrospective review of antimicrobial susceptibility data of all isolates of P. aeruginosa, (inpatient and outpatient) at the Detroit VAMC pre and post implementation of antibiotic cycling, over a 7-year period (2011-2017) was performed. Susceptibility testing was performed by reference broth micro-dilution methods in a central laboratory. Data analysis was performed using Pearson correlation coefficient score. Being a QI project, clinical data were not reviewed. Results A total of 977 isolates were identified during the study period. (drug usage are in DOT/1000 PD); CAZ and AZT use surged during 2013-14 from 5 to 8 dropping in 2015-17 to &amp;lt; 3; PTZ usage increased to 100 during 2011-14 but dropped to 38 in 2015-17 (drug shortage); CAR use averaged at 10 until 2016 and dropped to 8 in 2017; CIP use dropped by 50% from 30 in 2012 to 15 in 2017; P. aeruginosa susceptible to CEF decreased from 88% in 2012 to 81% in 2014 mirroring the increased use of CEF, AZT, CAZ, and CIP; AG use was very low at &amp;lt; 5. With restrictions on the use of AZT, CAZ, and CIP, from 2014-15, CEF susceptibility increased significantly to 95.5% in 2015. Drug shortage of PTZ in 2015 and increased use of CEF from 2015-17 led to a drop in susceptibility to (82%); P. aeruginosa susceptible to CAR and AG averaged at 88% and 97% respectively (2011-17). However, reintroduction PTZ, resulted in improved susceptibility of P. aeuruginosa to CEF by 40% within a year. Conclusion Judicious antimicrobial use and antibiotic rotation play a significant role in reversing drug resistance in P. aeuruginosa. Disclosures All Authors: No reported disclosures

The Path of More Resistance: a Comparison of National Healthcare Safety Network and Clinical Laboratory Standards Institute Criteria in Developing Cumulative Antimicrobial Susceptibility Test Reports and Institutional Antibiograms.

In the absence of antimicrobial susceptibility data, the institutional antibiogram is a valuable tool to guide clinicians in the empirical treatment of infections. However, there is a misunderstanding about how best to prepare cumulative antimicrobial susceptibility testing reports (CASTRs) to guide empirical therapy (e.g., routine antibiogram) versus monitoring antimicrobial resistance, with the former following guidance from the Clinical and Laboratory Standards Institute (CLSI) and the latter from the Centers for Disease Control and Prevention's National Healthcare Safety Network (NHSN). These criteria vary markedly in their exclusion or inclusion of isolates cultured repeatedly from the same patient. We compared rates of nonsusceptibility (NS) using annual data from a large teaching health care system subset to isolates eligible by either NHSN criteria or CLSI criteria. For a panel of the three most prevalent Gram-negative pathogens in combination with clinically relevant antimicrobial agents (or priority pathogen-agent combinations [PPACs]), we found that the inclusion of duplicate isolates by NHSN criteria yielded higher NS rates than when CLSI criteria (for which duplicate isolates are not included) were applied. Patients with duplicate isolates may not be representative of antimicrobial resistance within a population. For this reason, users of CASTR data should carefully consider that the criteria used to generate these reports can impact resulting NS rates and, therefore, maintain the distinction between CASTRs created for different purposes.