Clinical Laboratory Standards Institute Research Articles

Surveillance of healthcare associated infections at a tertiary care teaching hospital from 2014 to 2016: Prevalence, microbiological spectrum and antibiogram

Background: Healthcare-associated infections have emerged as a significant cause of mortality in the recent years. One of the major concerns in the prevalence of such infections is the development of multidrug-resistant microorganisms. Aim: The present surveillance study was conducted to assess the prevalence, microbiological spectrum, and antimicrobial susceptibility aminoof the microorganisms at a tertiary care hospital. Methods: The study was conducted between May 2014 and December 2016 including 466 patients (255 men and 211 women) diagnosed with healthcare-associated infections. Data related to sex, age, time of admission, type of surgery, and complication were collected. Samples of the pus, urine, and blood were collected and sent for isolation and characterization of microorganisms. Antimicrobial sensitivity was conducted by following the Clinical Laboratory Standards Institute (CLSI) guidelines. Data obtained were recorded in Microsoft Excel and analyzed using R 3.3.1; P < 0.05 indicative of significant differences. Result: Mean age of the patients was 41.01 ± 18.11 years. Prevalence results were highest in surgical site infec-tion (79.18%) and gram-negative organisms (80.92%) were the prevalent causes of infection. Escherichia coli (21.54%), Pseudomonas aeruginosa (15.76%), and Acinetobacter sp. (12.22%) were the predominant organ-isms with maximum sensitivity towards carbapenems, aminoglycosides, and cotrimoxazole, respectively. E. coli was the prevalent producer of AmpC and extended-spectrum beta-lactamases. Conclusion: Reduced sensitivity to the majority of antimicrobials has led to the prevalence of gram-negative organisms in the healthcare-associated infections. However, carbapenems and chloramphenicol along with aminoglycosides remain the effective broad-spectrum antimicrobials. Further studies are required strategies to minimize antibiotic resistance, which can lead to improvement in therapeutic methods. Keywords: Escherichia coli, Carbapenems, Surgical site infection, Lactamases

Antimikrobiyal Aktivitenin Belirlenmesinde Cross-Streak Metodu Kullanımı

Antimikrobiyal duyarlılık testleri, ilaçların keşfedilmesi, epidemiyoloji ve terapötik sonuçların tahmini için kullanılabilmektedir. Günümüzde mikrobiyal yaşamdaki dirençlilik artış göstermekte olduğu için antimikrobiyal bileşikler etkilerini kaybetmekte ve bu durum onları tehlikeye sokmaktadır. Ayrıca, antimikrobiyal ajanların etkileri, çoklu ilaca dirençli bakterilerle ilişkili tedavilerde başarısızlık göstermektedir. Bu durum, halk sağlığı için küresel bir endişe olma durumuna gelmiştir. Bu yüzden, yeni antimikrobiyal ajanların keşfedilmesi ve antimikrobiyal duyarlılık testlerinin yaygın olarak kullanılması ve geliştirilmesi gerekmektedir. Antimiktobiyal aktivitenin belirlenmesi için birçok teknik bulunmaktadır. Duyarlı mikroorganizmaları inhibe etmek amacıyla uygulanan bu tekniklerden çoğu, katı ya da yarı katı üretim ortamındaki difüzyon ile ilişkili metodlara dayalıdır. Bu teknikler arasında Cross-streak ise yeni antibiyotik keşfi için yapılan araştırmalarda kültürlerin nispeten hızlı bir şekilde taranmasını sağlayan kolay bir tekniktir. Fakat Cross-streak testinin en büyük dezavantajı, niceliksel verilerin elde edilmesindeki güçlüktür. Çünkü inhibisyon bölgesinin kenarları genellikle çok bulanık ve belirsizdir. Bazı antimikrobiyal duyarlılık test teknikleri, bu alandaki dikkat çekici adımlar belirlenerek Clinical Laboratory Standards Institute (CLSI) ve European Committee on Antimicrobial Susceptibility Testing (EUCAST) tarafından standardizasyona tabi tutulmuştur. Bu test prosedürü, spesifik test koşullarının ve metotlarının kullanımına gereksinim duymaktadır. Ayrıca, besiyeri ve inkübasyon koşulları ile zaman bu gereksinimler arasındadır. Hali hazırda kullanılan aktivite belirleme yöntemlerinden Cross-streak yönteminin iyi anlaşılıp geliştirilmesi önem arz etmektedir.

Acute rise in Multiple Drug Resistance Typhoid fever in Children in Rural Sindh: an Alarming Situation

Objective: Evaluation of the frequency of antimicrobial drug resistance in Salmonella typhiamong children of rural Sindh. Study Design: Cross sectional / observational study Place and Duration: At Department of Pediatric medicine Civil Hospital Mirpurkhas, Sindh from January 2019 to July 2019 Methodology: With approval of ethical committee and informed consent from parents/attendant blood samples (5ml) of 55 children with age between 0 to 15 years are obtained at outpatient department (OPD) or admitted in the ward with suspected enteric fever. The blood samples were used to obtain bacterial culture and antibiotic sensitivity was performed at diagnostic and research laboratory (DRC) of Liaquat University of Medical and Health Sciences (LUMHS). Blood culture and Antibiotic Susceptibility testing was performed according to standard protocol of Clinical Laboratory Standard Institute (CLSI) guidelines. Results: Among study population (n=55), 32 (58.2% were in age group 0 to 5 years, 20(36.4%) in age group of 6 to 10 years while only 3(5.5%) were in the age group of 11 to 15 years.While regarding gender,29(52.7%) were male while 26(36.4%) were females. S. typhi exhibited high resistance against ampicillin (93% n=51) and cotrimazole-trimethoprim (91%n= 50). About 82% (n=46) of culture was observed resistant to ciprofloxacin, whereas 84% (n=46) showed resistance to ceftriaxone, 84% (n=46) were resistant to cefixime. Out of these 55, 45(82%) showed antimicrobial sensitivity to meropenem, 34 (62%) to azithromycin, 10(18%) to ciprofloxacin, 09 (16%) to cefixime and ceftriaxone each, while only 05 patients showed sensitivity to (9%) to cotrimazole-trimethoprim and 04(7%) to Amoxicillin/clavulanic acid. Conclusion: Multiple drug resistance in S. typhiis high alert situation in our setup and needs prompt initiatives to combat.

PSVI-25 Antimicrobial resistance profiles of Pasteurella multocida, Mannheimia haemolytica and Moraxella spp. of bovine origin pre- and post- treatment with antimicrobials in calves

Abstract The current production system involves movement of calves combined with mixing animals, favouring the transmission of respiratory pathogens and increasing the risk of using antimicrobials. The aim of the study was to determine the presence and resistant profiles of Pasteurella multocida, Mannheimia haemolytica and Moraxella in the lungs of calves at arrival to the farm and after treatment with tulathromycin and florfenicol. Thoracic ultrasonography was performed in two batches of calves (n = 65 and 120, age=26±11.0, weight=45-55kg) at arrival, to select 27 calves/batch with lesions from low to severe. Bronchoalveolar lavage fluid (BALF) was collected on arrival (D0), D20 and D34, and also on D7 for the second batch. Pasteurella, Mannheimia and Moraxella were identified by VITEK. Detection of Mycoplasma bovis was performed by PCR. Minimal inhibitory concentration (MIC) was determined for 18 antimicrobials. Clinical breakpoints were defined by Clinical Laboratory Standards Institute. ERIC-PCR was performed in all isolates to assess similarities. Time effect was analysed by MIXED Procedure (SAS). At D0, 16 out of 54 BALFs contained P. multocida (n = 11), M. haemolytica (n = 5) and Moraxella (n = 4). The number of calves positive for primary pathogens decreased (P < 0.001) at D7 and D20, whereas by D34 positive animals leapt up to 21. MIC results demonstrated that P. multocida and M. haemolytica obtained at D0 were pansusceptible. Isolates of P. multocida collected after treatment, exhibited resistance to oxytetracycline, tilmicosin, tulathromycin, danofloxacin and enrofloxacin. ERIC-PCR demonstrated similar profiles of P. multocida and Moraxellain the two batches of calves after D7. Primary pathogens were susceptible to the initial treatment, however M. bovis was detected in all animals after D7. Resistant species appeared to recolonize the lungs after D34. ERIC-profile demonstrated that isolates recovered after treatment were different from those colonizing the lungs at arrival, suggesting recirculation of resistant bacteria between batches.

Detection of SHV and TEM-type Extended spectrum β-lactamase in bacterial isolates recovered from clinical samples of patients attending military hospitals

BackgroundMulti-drug resistant bacterial strains have been increasingly implicated in clinical infections worldwide and beta-lactamase production is one of the commonest mechanisms of resistance in these strains. This study investigated the prevalence of extended spectrum â-lactamase (ESBL)-producing isolates and determined the temoneira (TEM) and sulfhydryl variable (SHV) types implicated in two military hospitals in South-South Nigeria. MethodsThree-hundred and eighty (380) consecutive non-duplicate bacterial isolates (Gram negative bacilli) recovered from clinical samples were identified following standard techniques. Antimicrobial susceptibility tests were performed for each isolate following the Clinical Laboratory Standards Institute guidelines. Bacterial isolates recovered which comprised Escherichia coli, Klebsiella spp, Proteus spp and Pseudomonas aeruginosa were screened for ESBL using a phenotypic method (double disc synergy test). All positive isolates were screened for TEM and SHV genes by PCR method. ResultsSixty-five isolates (17.1%) were ESBL producing using phenotypic method, E. coli showed the highest ESBL prevalence (24.3%). One isolate was SHV positive (1.5%), 8 (12.3%) were TEM positive while 3 (4.6%) isolates harbored both SHV and TEM genes. Fluoroquinolone - ofloxacin showed marked activity against ESBL-producing isolates (90.8%) while the least active were ceftriaxone (9.2%), ceftazidime (3.1%) and ampicillin (1.5%). ConclusionThis study demonstrated that 17.1% of Gram-negative bacilli were ESBL producers. Screening of clinical isolates for ESBL should be implemented. The findings of this study suggest the need for caution in the use of antimicrobial agents in order to curb the incidence of antimicrobial resistance.

Bacteriological profile and antimicrobial resistance patterns of burn wound infections in a tertiary care hospital

BackgroundThe bacterial infections that prevail in the burnt patients continue to be a critical complication in the burnt patients and vary with time and place. Identification of bacterial pathogens with information of their antimicrobial susceptibility of burn wounds can help clinicians to select appropriate medication procedure as in providing them with suitable antibiotic for empirical treatment. MethodsRetrospective study of thirty-one months (Jan 2015 to July 2017) was designed to evaluate bacteria involved in burnt wound infection and its antimicrobial susceptibilities in a Burn Intensive Care Unit of Eastern India. Pus samples were cultured on cysteine Lactose electrolyte deficient agar (Hi-Media, India). Positive bacteria cultures were identified and tested for antimicrobial susceptibility using VITEK®2 (bioMerieux, Durham, NC, USA) and interpreted according to Clinical Laboratory Standards Institute guidelines. ResultsTwo hundred and seventy-two wound swabs from burnt patients were received, out of which 62.8% (n = 185) were revealed as positive for the presence of bacteria. Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii and E. coli were discovered to be the most common organisms in patients. Isolated bacteria were least resistant to TIGECYCLINE and COLISTIN. ConclusionData regarding the incidence of pathogens and their resistance patterns would benefit the clinicians to prescribe appropriate antibiotics, articulating policies for empirical antimicrobial therapy to control the different types of infections.

Hematological and Biochemical Reference Intervals for Mules in Chile.

Hematological and biochemical reference intervals are an important tool for health assessment and treatment decision-making in veterinary medicine. Lack of information about reference intervals (RI) in mules force professionals to apply reference intervals developed for horses or donkeys, with the risk of misinterpretation. Thus, the aim of this study was to determine hematological and biochemical RI for healthy mules and compare them with those proposed in literature for horses, donkeys and mules. A total of 142 healthy mules (mixed breed mares × Baudet du Poitou) of both sex, all between 7 and 22 years of age and between 290 and 500 kg of live weight were sampled and 32 blood parameters analyzed in order to calculate reference intervals according to the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and the Clinical Laboratory Standards Institute (CLSI) standards. The values obtained for Chilean mules were within the RI in three of the 21 variables where data was available for UK donkeys and for three of 22 RI available for working horses in Pakistan; no similarities were found with those from Portuguese mules. In the case of Chilean working horses RI, mules values were within range for 11 of 25 variables. The differences found in blood biochemistry may be explained by husbandry conditions, diet, type of work and biological features. Differences between mules' reference intervals and those from donkeys and working horses highlight the importance of having specific reference values for this equid hybrid and the need to develop further research in mules under different working conditions and genetic background.

Evaluation of Bio-Rad® discs for antimicrobial susceptibility testing by disc diffusion and the ADAGIO™ system for the automatic reading and interpretation of results.

The disc diffusion test is used for antimicrobial susceptibility testing worldwide. In this study, the performance of both Bio-Rad® antibiotic discs (as compared with Oxoid® discs) and the ADAGIO™ automated system for the reading of disc diffusion test results was evaluated with American Type Culture Collection (ATCC) quality control (QC) and wild strains of bacteria. Inhibition zones of both disc brands were read manually and through use of the ADAGIO™ system. Categorized interpretation of the results for each strain and antibiotic combination was summarized according to the Clinical Laboratory Standards Institute MS-100 (2017 update) manual and ADAGIO™ readings. Eight ATCC QC strains and 120 different wild strains were evaluated, to give a total of 1226 antibiotic/bacteria combinations and 2486 manual readings. One major error and four minor errors (0.08% and 0.34%, respectively) were detected via manual readings of the Bio-Rad® discs as compared with the Oxoid® discs. For the same number of antibiotic/bacteria combinations, five minor errors and one major error (0.42% and 0.08%, respectively) were detected with the Bio-Rad® discs read by the ADAGIO™ system. In addition, the number of times the automatic reading needed manual edition with Bio-Rad® discs was statistically lower than it did with Oxoid® discs (3.7% vs. 5.7%, p < 0.05). These findings support the hypothesis that Bio-Rad discs are not inferior to Oxoid® discs, and the performance of the ADAGIO™ system is comparable to that of manual readings with both disc brands.

Prevalence and Resistance Profiles of Vancomycin-resistant Enterococcal Isolates in Iran; An Eight-month Report from Nine Major Cities.

Enterococcal infections comprise a wide range of diseases with increasing importance due to the growing frequency of health-care-associated infections and the increasing incidence of antimicrobial resistance. Vancomycin-resistant Enterococcus (VRE) is an emerging drug-resistant organism responsible for increasing numbers of nosocomial infections in both adults and children. Few data are available on the epidemiology and impact of VRE infections in Iranians. In the present study, attempts were made to evaluate the prevalence and molecular characterization of VRE isolates from patients referred to several hospitals in Iran. Eight hundred and fourteen enterococcal clinical isolates from different patients were selected for this cross-sectional study during June 2018 and February 2019. Antimicrobial susceptibility testing was performed by standard methods according to the Clinical Laboratories Standards Institute (CLSI) guidelines. The vanA and vanB genes in VRE isolates were amplified by PCR. Our findings indicated that 20.7% of the isolates were collected from hospitalized patients in the ICU. Among all the isolates, 254 (30%) were identified as VRE strains. All of the VRE isolates were sensitive to linezolid. Moreover, only 39.9% of the VRE isolates harbored the vanA gene, while none of them carried the vanB gene. The present study reports the highest range of VRE infections in Iran. The constant surveillance and monitoring of VRE strains are recommended to limit the occurrence and spread of VRE clones within and among hospitals and community settings.

Characteristics and Antibiogram Studies of Bacteria Associated with Vegetables Stored In Raffia Baskets in Nigeria

Raffia baskets are used in rural communities to preserve fresh vegetables for a given period of time. This method of storage is aimed at extending the shelf life of the vegetables until they are used. Thus, this study was aimed at determining the microbial succession during storage and susceptibility pattern of bacterial isolates from stored leafy vegetables to various antibiotics. Five (5) leafy vegetables namely, Bitter leaf (Vernomia anydalira), Water leaf (Talinum triangulare), Fluted pumpkin leaf, (Telfairia occidentalis), Okazi leaf (Gnetum africana) and Scent leaf (Ocimum gratissimum) were obtained from the Nigerian Stored Products Research Institute (NSPRI) farm, Port Harcourt. These vegetables were stored in a raffia basket for fourteen (14) days while another set of the vegetables were left in the open air as control. This set up was monitored for changes to occur. Standard microbiological techniques were employed for the various analyses of the vegetable samples. Both cultural and molecular characterizations of the isolates were done. The disc diffusion method was used in determining the susceptibility pattern of the bacterial isolates. The results of the predominant microorganisms identified were of the genus; Bacillus, Pseudomonas, Enterococcus, Enterobacter, Bordetella, Staphylococcus, Myroides, Escherichia, Serratia, Micrococcus and Acetobacter. Also, Bacillus species occurred in all the vegetables while Enterococcus faecalis, Acetobacter orientalis, Bordetella pertussis, Myroides xuanwuensis and Bacillus flexus were isolated on the third day of storage from the vegetables. The total heterotrophic bacterial counts ranged from 1.8 x106 cfu/g to 1.25 x107 cfu/g (bitter leaf), 9x105 cfu/g to 9.0 x106 cfu/g (Scent leaf), 7 x105 cfu/g to 1.88 x107 cfu/g (Okazi), 3.2x106 cfu/g to 1.05x107 cfu/g (Fluted pumpkin leaf) and 8.4 x106 cfu/g to 2.04 x107 cfu/g (water leaf). Antibiogram of bacterial isolates revealed that they were resistant to Augmentin and Ceftazidime according to Clinical Laboratory Standard Institute schemes. Combination of the antibiotics showed that most of the isolates were 100% susceptible to ciprofloxacin + erythromycin, and ciprofloxacin + ceftriaxone. The study revealed that for all the vegetables, those stored in the basket lasted longer and were fresher compared to those kept in the open space. This study revealed that the raffia baskets are suitable for storage and preservation of leafy vegetables, but microbial succession occurred as a result of increase in the period of storage leading to the proliferation of microorganisms. This could be from aerosols or by chance inoculation, through handling or materials used or other microorganisms which are inherent in the vegetables because of their contact with the soil or water used in the washing of the leaves.

Bacterial Profile And Antibiotic Susceptibility Pattern Of Urinary Tract Infection Among Children Attending Felege Hiwot Referral Hospital, Bahir Dar, Northwest Ethiopia.

BackgroundUrinary tract infection (UTI) is a common and important clinical problem in pediatrics. Recurrent UTIs may lead to renal scarring, hypertension, and end-stage renal dysfunction later in life. The objective of the study was to determine bacterial profile and antimicrobial susceptibility pattern of urinary tract infections (UTIs) among children attending Felege Hiwot Referral Hospital (FHRH).MethodsA cross-sectional study was conducted from February 2013 to May 2013 among children 5–15 years of age with symptoms of UTI. Samples were processed for culture and identification. Antimicrobial susceptibility was done for positive urine cultures by the Kirby-Bauer’s disk diffusion method based on standards of the Clinical Laboratory Standard Institute (CLSI). Data were entered into Epi-data version 3.2.1 and exported to the Statistical Package for the Social Science (SPSS) version 20 statistical software. Fisher’s exact test and binary logistic regression test results were used.ResultsA total of 259 urine samples were collected from children with UTI. The result revealed 41 (15.8%) samples had significant bacteriuria, among which the most prevalent pathogen was E. coli 14 (34.1%) followed by Pseudomonas species. Gram-negative bacteria showed high level of sensitivity to ciprofloxacin (70), norfloxacin (63.4%) and ceftriaxone (60%), whereas the level of resistance was high to ampicillin (80%) and nitrofurantoin (70%). Gram-positive isolates showed high sensitivity to ciprofloxacin (77.8%), penicillin (72.8%) and erythromycin (72.7%). Multiple drug resistance (MDR) for Gram-positive and Gram-negative bacteria was 100% and 83.1%, respectively.ConclusionE. coli is the predominant bacteria isolated in the present study. The results showed that the prevalence of resistance to at least one antibiotic to commonly prescribed antimicrobials was high. Hence, the guidelines for empiric treatment of UTI should be re-evaluated periodically based on local studies.

Occurrence of Multi-drug Resistant Bacteria in Some Selected Street Food Samples

Antimicrobial resistance is a subject of great concern in the public health. The prevalence of antimicrobial resistance among food pathogens has increased during recent decades.&#x0D; Studying the incidence and antibiotic resistance pattern of bacterial species isolated from fish and vended street fruits. &#x0D; Eleven fish swabs and thirteen sliced fruit samples were collected and prepared for isolation of bacterial species through inoculation onto selective and non-selective nutrient media. The grown colonies were purified through subculturing on nutrient agar plates then identified by morphological and biochemical methods. The obtained pure cultures were then kept on nutrient agar slants. Testing antibiotic resistance of the isolated bacterial strains was studied by Kirby-Bauer disk diffusion method on Mueller Hinton agar using ten antibiotics belonging to different classes. The resultant inhibition zone was interpreted according to Clinical Laboratory Standard Institute.&#x0D; Twenty-eight bacterial cultures were isolated from the collected food samples. The conventional identification using morphological and biochemical methods of these cultures revealed presence of three Gram positive species; Staphylococcus aureus, Streptococcus sp. and Bacillus subtilis in addition to four Gram negative; Escherichia coli, Brucella sp., Enterococcus faecalis and Proteus mirabilis. The incidence of the obtained bacterial species was arranged as 29.16% for both S. aureus and E. faecalis followed by Brucella sp. 16.66%; B. subtilis &amp; E. coli 12.5% then Streptococcus sp. and P. mirabilis with an incidence of 8.33% each. Testing antibiotic resistance pattern of seven bacterial species against ten antibiotics showed that, among three Gram positive bacterial species, only one (33.33%) strain S. aureus exhibited resistance to six antibiotics; amoxicillin, erythromycin, ciprofloxacin, ceftriaxone, fluconazole and dicloxacillin. Among four Gram negative bacterial strains only one (25.0%) strain Enterococcus faecalis exhibited resistance to eight antibiotics; amoxicillin, streptomycin, chloramphenicol, cotrimoxazole, ciprofloxacin, ofloxacin, sparfloxacin and cloxacillin.&#x0D; Occurrence of multi-drug resistant bacteria in fish and vended street fruits poses not only risk of disease to the foods but public health hazard to food handlers and consumers in general. Also the result of this study recommended augmentin and cephazolin as good choice antibiotics for treatment of infection in the study area.

1608. Use of Selective Reporting of Antimicrobial Susceptibilities and Its Impact on Antimicrobial Resistance Surveillance—National Healthcare Safety Network, 2017–2018

BackgroundSelective reporting (SR), recommended by the 2016 IDSA/SHEA antimicrobial stewardship guidelines, is a strategy to guide prescribing decisions by limiting the antimicrobial susceptibility testing (AST) results available to prescribers. Yet, SR carries risks that cumulative antibiograms reflect only partial AST results. The Clinical Laboratory Standards Institute (CLSI) M100 performance standards stipulate that AST results should be routinely reported for some antimicrobials (Group A agents) while SR is appropriate for other antimicrobials (Group B agents). We assessed the extent of SR use and its impact on national antimicrobial resistance (AR) surveillance.MethodsWe used Enterobacteriaceae (EB) and Staphylococcus aureus (SA) blood culture AST results that hospitals reported for group A and B agents to the CDC’s National Healthcare Safety Network’s AR option from 2017 through 2018. Routine reporting for an organism-agent combination was defined as results reported for ≥ 90% isolates for the hospital’s most frequently reported agents. SR was defined as a shortfall of > 20% in results reported for an agent compared with a routinely reported agent in a hospital that reported ≥ 30 isolates. We compared hospital antibiograms between SR and non-SR hospitals. We also identified isolate characteristics associated with AST reporting in SR hospitals.ResultsAmong 242 and 185 hospitals reported ≥ 30 isolates, many showed patterns of SR (Figure 1). Of 437 and 425 hospitals reported ≥ 1 isolate, only 112 (26%) and 152 (36%) routinely reported AST results for all group A agents for EB and SA, respectively. For EB, 345 (79%) hospitals routinely reported AST results for ciprofloxacin or levofloxacin, although both are group B agents. For SA, 324 (76%) routinely reported vancomycin (Figure 2). Antibiograms for many agents differed between SR and non-SR hospitals (Figure 3, 4). In SR hospitals, non-susceptibility to narrower-spectrum drugs, patient location, age, and some species among EB were associated with AST reporting.ConclusionAST results reporting vary across hospitals and agents, and CLSI’s SR standards are used inconsistently. For AR surveillance, complete reporting calls for solutions that bypass SR. In the meantime, SR should be taken into account in national AR benchmarking. Disclosures All authors: No reported disclosures.

528. Longitudinal Evaluation of Chlorhexidine Resistance Among Multidrug-Resistant Organisms in Relation to Intervention of Daily Chlorhexidine Bathing in Adult Intensive Care Units

BackgroundChlorhexidine digluconate (CHG), the most widely used antiseptic, has recently been applied to patient washing to decolonize the multidrug-resistant organisms (MDROs), but there are little data on susceptibilities of MDROs to CHG. The purpose of this study was to evaluate CHG resistance among MDROs before and after the intervention of daily CHG bathing in adult intensive care units (ICUs).MethodsThe intervention of daily body washing with 2% CHG cloths were taken in adult patients the medical or surgical ICU of 23-bed by a crossover manner for 6 months (MICU, July to December 2017; SICU, January to June 2018) in a 1,050-bed, university hospital in the Republic of Korea. Available MDRO isolates were randomly selected from clinical cultures of ICU patients within 6 months before, during and after the intervention, including MRSA, MR-CoNS, VRE, Carbapenem-resistant Pseudomonas aeruginosa (CR-PA), CR-Acinetobacter baumannii (CR-AB). Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method set by the Clinical Laboratory Standards Institute. Determination of the minimum bactericidal concentrations (MBCs) was performed by subculturing 10 µL from each well without visible microbial growth. Cumulative amounts of CHG used in both ICUs was estimated across the study period from January 2008 to June 2018.ResultsThe cumulative CHG consumption from both ICUs increased sharply from 27,503 g to 29,556 g after one-year intervention. The ranges of MICs and MBCs of CHG among MDRO clinical isolates selected by a 6-month phase are summarized in Table 1. Particularly, CR-PA and CR-AB isolates revealed four to eight times higher MICs and MBCs compared with the majority of Gram-positives excepting some VRE isolates. On the other hand, neither MICs and MBCs ranges of CHG from the MDRO isolates nor the monthly incidence of the MDROs from both ICUs were significantly increased before and after the intervention of daily CHG bathing.ConclusionThis study indicates that some Gram-negative MDRO isolates with higher MICs and MBCs of CHG might be from longstanding exposure to CHG or efflux pumps. Although 2% daily CHG bathing uses over 1,000 times higher concentrations than the lethal concentration, it might be needed to monitor CHG resistance among MDROs. Disclosures All authors: No reported disclosures.

1467. Antimicrobial Susceptibility and Molecular Characterization of Extended-Spectrum β-Lactamase of Escherichia coli and Klebsiella pneumoniae of Urine Samples Isolated from Community Patients in South Brazil

BackgroundEnterobacteriaceae is the main pathogens of UTI. It is important to be aware the local epidemiological data for an appropriate initial treatment. Resistance to antimicrobial agents has increased, especially to first-choice antibiotics in the treatment of cystitis. Our objective is to asses the antimicrobial susceptibility profile from uropathogens isolated in community and evaluated the dissemination of extended-spectrum ß lactamase (ESBL), in E. coli and K. pneumoniae in south of Brazil.MethodsFrom June 2016 to June 2017, all urine samples collected in the Basic Health Units and Emergency Departments were sent to a Central Laboratory. Identification and susceptibility tests were performed on the VITEK® 2 (bioMérieux, France) system. Clinical Laboratory Standards Institute (CLSI) breakpoints were used for the interpretation of susceptibility. Positive cultures were defined as those demonstrating ≥105 CFU / mL (colony-forming units). The presence of ESBL was also subjected to the Chrom ID BLEE® agar plate test (bioMérieux- Marcyl’Etoile, France). PCR technique uses specific primers for genes blaTEM and blaSHV. Detection of the blaCTX-M genes was performed by multiplex PCR.ResultsA total of 56,555 microbiologic tests were performed, 8189 were positive. Women were responsible for 89.4%, and 10% were pregnant. Table 1 shows uropathogens isolated. Graphic 1 shows antimicrobial susceptibility. Extended-spectrum ß lactamase production was present in 6.7% (n = 489). People older than 60 years had ESBL more frequent (P <0.05) as well as being pregnant is not related to ESBL (P <0.05). Table 2 shows the distribution of the bla genotypes. Table 3: Distribution of blaCTX-M. Among blaCTX-M1 genotype, blaCTX-M15 was the most frequent.ConclusionIn this study, the most frequent uropathogen isolated was E. coli followed by K. pneumoniae. Cotrimoxazol had high rates of resistance and nitrofurantoin the lowest. Quinolone resistance is more than 10%. Sensitivity to aminoglycosides and carbapenems remains high.We found relevant frequency of ESBL, CTX-M-1-group most commonly found. Among CTX-M-1, blaCTX-M15 was the most isolated. Disclosures All authors: No reported disclosures.

634. Incidence of vanC-Mediated Vancomycin-Resistant Enterococcus Bloodstream Infections at Children’s Hospital of Colorado and Implications for Empiric Enterococcal Therapy

BackgroundThe most well-known Enterococcal species, E. faecium and E. faecalis, can harbor high-level vancomycin resistance mediated by acquired vanA and vanB operons. However, other Enterococcal species such as E. gallinarum and E. casseliflavus (VCE), harbor intrinsic low-level vancomycin resistance mediated by an intrinsic vanC operon, and the incidence of these pathogens among pediatric patients is not clear. As the antibiotic resistance pattern of VCE is different than E. faecium and E. faecalis, a high prevalence of VCE may have implications for antibiotic therapy. We describe the incidence and susceptibility of VCE bloodstream infections at a large children’s hospital and compare to E. faecalis and E. faecium.MethodsPositive blood culture results from 2013 to 2018 were obtained from the Children’s Hospital of Colorado data warehouse. All first-time positive cultures for Enterococcus were analyzed for species, susceptibility, and hospital unit location. First-time positive was defined as being at least 2 weeks after any previous positive Enterococcus blood culture. Susceptibilities were categorized by clinical laboratories standards institute (CLSI) guidelines.ResultsOf 240 positive isolates, 7% were ampicillin susceptible and vancomycin nonsusceptible (resistant or intermediate), vs. 6% that were ampicillin resistant and vancomycin susceptible. An additional 3% of isolates were not susceptible to either antibiotic; all of these were E. faecium. VCE accounted for 12% of our isolates while E. faecalis and E. faecium accounted for 66% and 16%, respectively. All VCE were susceptible to ampicillin, but 52% were nonsusceptible to vancomycin. VCE incidence, ampicillin resistance, and vancomycin nonsusceptibility were most prevalent in our hematology, oncology, and bone marrow transplant (BMT) units.ConclusionAt our institution, an as yet unspeciated Enterococcus is equally likely to be ampicillin susceptible and vancomycin nonsusceptible as ampicillin resistant and vancomycin susceptible. This is driven by a significant incidence of VCE, especially on our hematology, oncology, and BMT units. Therefore, vancomycin may not provide adequate empiric Enterococcal coverage on these units, and the addition of ampicillin will be recommended. Disclosures All authors: No reported disclosures.

2030. Impact of an Antimicrobial Stewardship Program on Carbapenem Susceptibility in a National Hospital in Bhutan

BackgroundThe overuse of broad-spectrum antibiotics drives antimicrobial resistance (AMR), and the prevalence of highly-resistant Gram-negative infections is increasing across the world, especially in low- and middle-income countries (LMIC). Carbapenem resistance is of particular concern since these are often the last line agents. Antimicrobial restriction is an antimicrobial stewardship intervention (AMS) that aims to reduce the use of broad-spectrum antibiotics to preserve antimicrobial susceptibility.MethodsThis is retrospective, observational study of antibiotic consumption and prevalence of antibiotic resistance of bacterial isolates from inpatients at Jigme Dorji Wangchuck National Referral Hospital, a 350-bed multi-specialty hospital in Thimphu, Bhutan. Antibiotic consumption and antimicrobial susceptibility were monitored from January 2015 to December 2017 by the pharmacy department and the microbiology lab, respectively. Antibiotic consumption was measured using defined daily doses (DDD) and expressed as DDDs per 1,000 persons per day. The antibiotic susceptibility was determined using the Clinical Laboratory Standards Institute (CLSI) guideline. A hospital AMS program with multidisciplinary team and good hospital managerial/ leadership support were initiated in 2016 and interventions included antimicrobial restrictions, educations, guidelines for use, post prescription review, de-escalation, audit and feedback.ResultsFrom 2015 to 2016, the DDDs of carbapenems and piperacillin–tazobactam (PTZ) increased while ceftriaxone decreased (Figure 1). After the AMS program was implemented in 2016, the annual DDDs of carbapenems decreased while PTZ and ceftriaxone increased. Antimicrobial susceptibility of Klebsiella pneumoniae and Escheriachia coli blood isolates to carbapenems and ceftriaxone increased from 2016 to 2017: 50/61 (82%) vs. 45/49 (92%) and 24/91 (26%) vs. 31/92 (34%), respectively.ConclusionImplementing an AMS program that restricted the use of carbapenems resulted in a decrease in carbapenem use and increased antimicrobial susceptibility for carbapenems and ceftriaxone. AMS interventions can be successful to decrease carbapenem-resistance in LMIC.

1594. Ceftolozane–Tazobactam Demonstrates Higher In Vitro Susceptibility than Ceftazidime–Avibactam Against Pseudomonas aeruginosa Isolated from Respiratory Tract of Adult Cystic Fibrosis Patients

Background Pseudomonas aeruginosa is a commonly isolated pathogen in adults with cystic fibrosis (CF). Antimicrobial resistance is an escalating problem due to chronic colonization and frequent antimicrobial exposure. Ceftolozane–tazobactam (C/T) and ceftazidime–avibactam (CZA) exhibit promising activity against antimicrobial-resistant organisms, including P. aeruginosa. In this study, we compared in vitro activity of C/T and CZA against P. aeruginosa isolated from respiratory cultures obtained from adult patients with CF.MethodsThis is a retrospective study of respiratory cultures positive for P. aeruginosa collected from adult CF patients between January 1, 2015 to November 30, 2018. The first isolate per patient per year that underwent susceptibility testing for C/T, CZA, and colistin were included in the study. All isolates underwent in-house susceptibility testing for 9 anti-pseudomonal agents according to the methodology established by the Clinical Laboratory Standards Institute (CLSI). Susceptibility testing of C/T, CZA, and colistin were performed by a reference lab. Isolates were classified into 3 drug-resistant categories using the following definition: multidrug-resistant (MDR) non-susceptible (NS) to ≥1 agent in ≥3 different antimicrobial classes, extensive drug-resistant (XDR) NS to 4 or 5 different classes, and pan drug-resistant (PDR) NS to all 6 classes except colistin.ResultsForty-two P. aeruginosa respiratory isolates from 32 patients with CF were included. The overall susceptibility to C/T and CZA was 59.5% and 42.9%, respectively. Thirty-eight (90%) isolates were considered MDR with susceptibility of 55.3% to C/T and 44.7% to CZA. Among the 11 XDR isolates, susceptibility to C/T was 81.8% vs. CZA 72.7%. Susceptibility to C/T vs. CZA was also higher (37.5% vs. 25%) among the 24 PDR isolates.ConclusionAmong P. aeruginosa isolated from CF respiratory cultures, C/T appears to have better in vitro activity compared with CZA, and remained true among isolates considered XDR and PDR. These results suggest using C/T while awaiting susceptibilities when standard anti-pseudomonal agents cannot be used. Future studies evaluating clinical outcomes for the treatment of pulmonary CF exacerbations are needed to assess the applicability of in vitro susceptibility data.Disclosures All authors: No reported disclosures.

1955. Novel Compound Reverses Vancomycin Resistance in Vancomycin-resistant Enterococci (VRE)

Background Enterococcus causes 14% of all hospital-associated infections (HAIs) according to Centers for Disease Control and Prevention (CDC) data. 35.5% of these HAIs are caused by Vancomycin-resistant Enterococci (VRE) including highly fatal bacteremia, surgical site infections, and urinary tract infections. We present a novel synthetic compound, HSD 03-21 that could make VRE completely susceptible to vancomycin in-vitro.MethodsHSD 03-21 was synthesized de novo from a hydroxybenzylidene – indolinone backbone in our laboratory. The minimum inhibitory concentration (MIC) of HSD 03-21 and vancomycin against VRE were determined according to clinical laboratory standards institute (CLSI) guidelines. The standard checkerboard assay was used to determine vancomycin-HSD 03-21 interactions against VRE. Briefly, HSD 03-21 and vancomycin at 10 mg/mL were prepared and diluted serially along the ordinate and abscissa of 96-well microtiter plates, respectively. Bacteria was standardized using the 0.5 McFarland standard, diluted (1:100), aliquoted into respective wells and incubated at 37oC for 18–20 hours. All assays were run in triplicates. The fractional inhibitory concentration (FIC) index was calculated for each combination. The FIC of either agent was calculated as: FIC (vancomycin) = MIC of vancomycin in combination/MIC of vancomycin alone and FIC (HSD 03-21) = MIC of HSD 03-21 in combination/MIC of HSD 03-21 alone. The cumulative FIC index ∑FICI was then calculated as: ∑FIC = FIC(vancomycin) + FIC(HSD 03-21). The calculated ∑FIC indices were interpreted as synergistic if ∑FIC: ≤ 0.5.ResultsThe MIC of vancomycin for VRE faecalis was 256 μg mL−1 while that of HSD 03-21 was 128 μg mL−1. When vancomycin was combined with HSD 03-21 at 8 μg mL−1 (1/16 MIC), there was a reduction in MIC of vancomycin to 0.5 μg mL−1. The combination showed excellent synergy with ∑FIC of 0.06.ConclusionHSD 03-21 reduced the MIC of vancomycin from 256 to 0.5 μg mL−1. This has an immense potential of changing the way we use vancomycin and in the treatment of VRE infections. Translation of this novel compound could save thousands of lives from VRE and the failures and inherent toxicities of current doses of vancomycin. Disclosures All Authors: No reported Disclosures.

630. Clinical and Molecular Characteristics of Carbapenem-Resistant Enterobacteriaceae in Qatar: A Retrospective and Prospective Observational Study

BackgroundThere are limited data describing carbapenem-resistant Enterobacteriaceae (CRE) from the Arabian Gulf region. Our aims were to describe the clinical, microbiological and molecular characteristics of CRE infections and to characterize the gene displaying resistance to carbapenem.MethodsRetrospective and prospective review of clinical, microbiological and molecular characteristics of CRE isolated between April 2015 and November 2017 at 7 tertiary hospitals in Qatar. Susceptibility testing was performed and interpreted according to Clinical Laboratory Standards Institute methodology and breakpoints. Carbapenemase genes were identified using PCR. Whole-genome sequencing followed by bioinformatics analysis was performed on a subset of samples for accurate detection of resistant genes. SPSS V.21.0 was used for all statistical analyses.ResultsA total of 144 nonrepeating CRE strains were recovered from 137 individuals over the study period, of which 35 (24.3%) represented colonization. Klebsiella spp. (98, 68.1%) and E. coli (38, 26.4%) were the most predominant. The most prevalent carbapenemases were NDM (69, 47.9%), OXA-48 (36, 25.0%), and KPC (15, 10.4%). Sixteen (11.1%) strains possessed multiple carbapenemase genes but none were detected in 37 (25.7%) strains. Genomic analysis also detected the presence of NDM-7, NDM-5, NDM1, VIM4, and OXA48-like carbapenemase genes among 34 clinical samples. The majority of the strains were susceptible to tigecycline (124, 86.1%), fosfomycin (122, 84.7%) and amikacin (102, 70.8%). There were 109 CRE infections involving the urinary tract (40, 36.7%), bloodstream (31, 28.4%), and respiratory tract (17, 15.6%). Fifty-seven (52.3%) were males and the median age was 57 years (range 3–97). Baseline comorbidities included diabetes (57, 52.3%), chronic kidney disease (27, 24.8%), and cancer (27, 24.8%) (Table 1). Within the 30 days preceding CRE infection, 38 (34.9%) had received carbapenem therapy, 65 (59.6%) had undergone invasive procedures and 33 (30.3%) had had surgery. All-cause 30-day mortality was 29.4%. The only variable independently associated with mortality was baseline SAPS Score (Table 2).ConclusionNDM and OXA-48 are the predominant carbapenemases in Qatar. CRE infections are associated with high overall mortality. Disclosures All authors: No reported disclosures.